National Library of Energy BETA

Sample records for volatile sub stances

  1. Interfacial charge-mediated non-volatile magnetoelectric coupling in Co<sub>0.3sub>Fe>0.7sub>/Ba>0.6sub>Sr>0.4sub>TiO>3sub>/Nb:SrTiO>3sub> multiferroic heterostructures

    SciTech Connect (OSTI)

    Zhou, Ziyao; Howe, Brandon M.; Liu, Ming; Nan, Tianxiang; Chen, Xing; Mahalingam, Krishnamurthy; Sun, Nian X.; Brown, Gail J.

    2015-01-13

    The central challenge in realizing non-volatile, E-field manipulation of magnetism lies in finding an energy efficient means to switch between the distinct magnetic states in a stable and reversible manner. In this work, we demonstrate using electrical polarization-induced charge screening to change the ground state of magnetic ordering in order to non-volatilely tune magnetic properties in ultra-thin Co<sub>0.3sub>Fe>0.7sub>/Ba>0.6sub>Sr>0.4sub>TiO>3sub>/Nb:SrTiO>3sub> (001) multiferroic heterostructures. A robust, voltage-induced, non-volatile manipulation of out-of-plane magnetic anisotropy up to 40 Oe is demonstrated and confirmed by ferromagnetic resonance measurements. This discovery provides a framework for realizing charge-sensitive order parameter tuning in ultra-thin multiferroic heterostructures, demonstrating great potential for delivering compact, lightweight, reconfigurable, and energy-efficient electronic devices.

  2. An advanced hybrid reprocessing system based on UF{sub 6} volatilization and chromatographic separation

    SciTech Connect (OSTI)

    Wei, Yuezhou; Liu, Ruiqin; Wu, Yan; Zu, Jianhua; Zhao, Long; Mimura, Hitoshi; Shi, Weiqun; Chai, Zhifang; Yang, Jinling; Ding, Youqian

    2013-07-01

    To recover U, Pu, MA (Np, Am, Cm) and some specific fission products FPs (Cs, Sr, Tc, etc.) from various spent nuclear fuels (LWR/FBR: Oxide, Metal Fuels), we are studying an advanced hybrid reprocessing system based on UF6 volatilization (Pyro) and chromatographic separation (Aqueous). Spent fuels are de-cladded by means of thermal and mechanical methods and then applied to the fluorination/volatilization process, which selectively recovers the most amount of U. Then, the remained fuel components are converted to oxides and dissolved by HNO{sub 3} solution. Compared to U, since Pu, MA and FPs are significantly less abundant in spent fuels, the scale of the aqueous separation process could become reasonably small and result in less waste. For the chromatographic separation processes, we have prepared different types of porous silica-based organic/inorganic adsorbents with fast diffusion kinetics, improved chemical stability and low pressure drop in a packed column. So they are advantageously applicable to efficient separation of the actinides and FP elements from the fuel dissolved solution. In this work, adsorption and separation behavior of representative actinides and FP elements was studied. Small scale separation tests using simulated and genuine fuel dissolved solutions were carried out to verify the feasibility of the proposed process. (authors)

  3. Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. I. Electronic structures and properties of MCl{sub 4} and MOCl{sub 2} (M = Ti, Zr, Hf, and Rf)

    SciTech Connect (OSTI)

    Pershina, V.; Borschevsky, A.; Iliaš, M.

    2014-08-14

    Relativistic, infinite order exact two-component, density functional theory electronic structure calculations were performed for MCl{sub 4} and MOCl{sub 2} of group-4 elements Ti, Zr, Hf, and element 104, Rf, with the aim to predict their behaviour in gas-phase chromatography experiments. RfCl{sub 4} and RfOCl{sub 2} were shown to be less stable than their lighter homologs in the group, tetrachlorides and oxychlorides of Zr and Hf, respectively. The oxychlorides turned out to be stable as a bent structure, though the stabilization energy with respect to the flat one (C{sub 2v}) is very small. The trend in the formation of the tetrachlorides from the oxychlorides in group 4 is shown to be Zr < Hf < Rf, while the one in the formation of the oxychlorides from the chlorides is opposite. All the calculated properties are used to estimate adsorption energy of these species on various surfaces in order to interpret results of gas-phase chromatography experiments, as is shown in Paper II.

  4. Experimental studies of actinide volatilities with application to mixed waste oxidation processors

    SciTech Connect (OSTI)

    Krikorian, O.H.; Ebbinghaus, B.B.; Condit, R.H.; Adamson, M.G.; Fontes, A.S. Jr.; Fleming, D.L.

    1993-04-30

    The transpiration technique is used to measure volatilities of U from U{sub 3}O{sub 8}(s), Pu from PuO{sub 2}(s) and Pu and Am from PuO{sub 2}/2%AmO{sub 2}(s) in the presence of steam and oxygen at temperatures ranging from 900 to 1300{degree}C.

  5. Volatile fluoride process for separating plutonium from other materials

    DOE Patents [OSTI]

    Spedding, F. H.; Newton, A. S.

    1959-04-14

    The separation of plutonium from uranium and/or fission products by formation of the higher fluorides off uranium and/or plutonium is described. Neutronirradiated uranium metal is first converted to the hydride. This hydrided product is then treated with fluorine at about 315 deg C to form and volatilize UF/sub 6/ leaving plutonium behind. Thc plutonium may then be separated by reacting the residue with fluorine at about 5004DEC and collecting the volatile plutonium fluoride thus formed.

  6. Oil Price Volatility

    U.S. Energy Information Administration (EIA) Indexed Site

    Speculation and Oil Price Volatility Robert J. Weiner Robert J. Weiner Professor of International Business, Public Policy & Professor of International Business, Public Policy & Public Administration, and International Affairs Public Administration, and International Affairs George Washington University; George Washington University; Membre Associ Membre Associ é é , GREEN, Universit , GREEN, Universit é é Laval Laval EIA Annual Conference Washington Washington 7 April 2009 7 April

  7. Fluorination behavior of UO{sub 2}F{sub 2} in the presence of F{sub 2} and O{sub 2}

    SciTech Connect (OSTI)

    Matsuda, Minoru; Sato, Nobuaki; Kirishima, Akira; Tochiyama, Osamu

    2007-07-01

    To apply the fluoride volatility process to the spent nuclear fuel, fluorination of UO{sub 2} by fluorine has been studied. In this reaction, it is possible that the U-O-F compounds, such as UO{sub 2}F{sub 2}, are produced. Therefore, study of such compounds is useful in order to know the fluorination behavior of UO{sub 2}. This paper presents the fluorination behavior of UO{sub 2}F{sub 2} in the presence of F{sub 2} and O{sub 2}, analyzed by thermogravimetry and differential thermal analysis (TG-DTA) method using anti-corrosion type differential thermo-balance. In fluorine gas, exothermic peaks appeared and volatilization of UF{sub 6}. In oxygen gas, only slowly pace decomposition was measured from UO{sub 22} to UF{sub 6} and UO{sub 3}. (authors)

  8. ARM - Measurement - Volatile organic compounds

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The quantity or concentration measure of volatile organic compounds including both man-made and naturally occurring chemical compounds (this is inclusive of hydrocarbons)....

  9. Volatile chemical reagent detector

    DOE Patents [OSTI]

    Chen, Liaohai; McBranch, Duncan; Wang, Rong; Whitten, David

    2004-08-24

    A device for detecting volatile chemical reagents based on fluorescence quenching analysis that is capable of detecting neutral electron acceptor molecules. The device includes a fluorescent material, a contact region, a light source, and an optical detector. The fluorescent material includes at least one polymer-surfactant complex. The polymer-surfactant complex is formed by combining a fluorescent ionic conjugated polymer with an oppositely charged surfactant. The polymer-surfactant complex may be formed in a polar solvent and included in the fluorescent material as a solution. Alternatively, the complex may be included in the fluorescent material as a thin film. The use of a polymer-surfactant complex in the fluorescent material allows the device to detect both neutral and ionic acceptor molecules. The use of a polymer-surfactant complex film allows the device and the fluorescent material to be reusable after exposing the fluorescent material to a vacuum for limited time.

  10. Combustion of volatile matter during the initial stages of coal combustion

    SciTech Connect (OSTI)

    Marlow, D.; Niksa, S.; Kruger, C.H.

    1990-08-01

    Both the secondary pyrolysis and combustion of the volatiles from a bituminous coal will be studied. Devolatilization and secondary pyrolysis experiments will be conducted in a novel flow reactor in which secondary pyrolysis of the volatiles occurs after devolatilization is complete. This allows unambiguous measurements of the yields from both processes. Measurements will be made for reactor temperatures from 1500 to 1700 K, and a nominal residence time of 200 msec. These conditions are typical of coal combustion. Yields of tar, soot, H{sub 2}, CO, CH{sub 4}, and C{sub 2} and C{sub 3} hydrocarbons will be determined as a function of reactor temperature. The yields will be reported as a function of the temperature of the reactor. The instrumentation for temperature measurements will be developed during future studies. Combustion studies will be conducted in a constant volume bomb, which will be designed and constructed for this study. Tar and soot will be removed before introducing the volatiles to the bomb, so that only the combustion of the light gas volatiles will be considered. The burning velocities of light gas volatiles will be determined both as functions of mixture stoichiometry and the temperature at which the volatiles are pyrolysed. 90 refs., 70 figs., 13 tabs.

  11. Investigation on coal pyrolysis in CO{sub 2} atmosphere

    SciTech Connect (OSTI)

    Lunbo Duan; Changsui Zhao; Wu Zhou; Chengrui Qu; Xiaoping Chen [Institute for Thermal Power Engineering of Southeast University, Nanjing (China)

    2009-07-15

    Considerable studies have been reported on the coal pyrolysis process and the formation of SO{sub 2} and NOx processors such as H{sub 2}S, COS, SO{sub 2}, HCN, and NH{sub 3} in inert atmospheres. Similar studies in CO{sub 2} atmosphere also need to be accomplished for better understanding of the combustion characteristics and the SO{sub 2}/NOx formation mechanism of oxy-fuel combustion, which is one of the most important technologies for CO{sub 2} capture. In this study, thermogravimetry coupled with Fourier Transform Infrared (TG-FTIR) analysis was employed to measure the volatile yield and gas evolution features during coal pyrolysis process in CO{sub 2} atmosphere. Results show that replacing N{sub 2} with CO{sub 2} does not influence the starting temperature of volatile release but seems to enhance the volatile releasing rate even at 480{sup o}C. At about 760{sup o}C, CO{sub 2} prevents the calcite from decomposing. In CO{sub 2} atmosphere, the volatile yield increases as the temperature increases and decreases as the heating rate increases. COS is monitored during coal pyrolysis in CO{sub 2} atmosphere while there are only H{sub 2}S and SO{sub 2} formed in N{sub 2} atmosphere. The COS is most likely formed by the reaction between CO{sub 2} and H{sub 2}S. No NH{sub 3} was monitored in this study. In CO{sub 2} atmosphere, the gasification of char elevates the conversion of char-N to HCN. The HCN yield increases as the temperature increases and decreases as the heating rate increases. 20 refs., 13 figs., 3 tabs.

  12. Volatile organic compound sensor system

    DOE Patents [OSTI]

    Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.; Wong, Gregory K.

    2011-03-01

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  13. Volatile organic compound sensor system

    DOE Patents [OSTI]

    Schabron, John F. (Laramie, WY); Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Laramie, WY); Sorini-Wong, Susan S. (Laramie, WY)

    2009-02-10

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  14. Uncorrelated volatile behavior during the 2011 apparition of comet C/2009 P1 Garradd

    SciTech Connect (OSTI)

    Feaga, Lori M.; A'Hearn, Michael F.; Farnham, Tony L.; Bodewits, Dennis; Sunshine, Jessica M.; Gersch, Alan M.; Protopapa, Silvia [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Yang, Bin [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Drahus, Michal [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Schleicher, David G., E-mail: feaga@astro.umd.edu [Lowell Observatory, Flagstaff, AZ 86001 (United States)

    2014-01-01

    The High Resolution Instrument Infrared Spectrometer (HRI-IR) on board the Deep Impact Flyby spacecraft detected H{sub 2}O, CO{sub 2}, and CO in the coma of the dynamically young Oort Cloud comet C/2009 P1 (Garradd) post-perihelion at a heliocentric distance of 2 AU. Production rates were derived for the parent volatiles, Q {sub H2O} = 4.6 0.8 10{sup 28}, Q {sub CO2} = 3.9 0.7 10{sup 27}, and Q {sub CO} = 2.9 0.8 10{sup 28} molecules s{sup 1}, and are consistent with the trends seen by other observers and within the error bars of measurements acquired during a similar time period. When compiled with other observations of Garradd's dominant volatiles, unexpected behavior was seen in the release of CO. Garradd's H{sub 2}O outgassing, increasing and peaking pre-perihelion and then steadily decreasing, is more typical than that of CO, which monotonically increased throughout the entire apparition. Due to the temporal asymmetry in volatile release, Garradd exhibited the highest CO to H{sub 2}O abundance ratio ever observed for any comet inside the water snow line at ?60% during the HRI-IR observations. Also, the HRI-IR made the only direct measurement of CO{sub 2}, giving a typical cometary abundance ratio of CO{sub 2} to H{sub 2}O of 8% but, with only one measurement, no sense of how it varied with orbital position.

  15. CVD method for forming B.sub.i -containing oxide superconducting films

    DOE Patents [OSTI]

    Wessels, Bruce W. (Wilmette, IL); Marks, Tobin J. (Evanston, IL); Richeson, Darrin S. (Evanston, IL); Tonge, Lauren M. (Sanford, MI); Zhang, Jiming (Chicago, IL)

    1994-01-01

    Films of high T.sub.c Bi-Sr-Ca-Cu-O superconductor have been prepared by MOCVD using volatile metal organic precursors and water vapor. The metal organic precursors are volatized along with a bismuth source, such as Bi(C.sub.6 H.sub.5).sub.3, deposited on a heated substrate to form a film, and annealed.

  16. Volatile organic compound sensing devices

    DOE Patents [OSTI]

    Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

    1995-08-29

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

  17. Volatile organic compound sensing devices

    DOE Patents [OSTI]

    Lancaster, Gregory D.; Moore, Glenn A.; Stone, Mark L.; Reagen, William K.

    1995-01-01

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

  18. Role of SrMoO{sub 4} in Sr{sub 2}MgMoO{sub 6} synthesis

    SciTech Connect (OSTI)

    Vasala, S.; Yamauchi, H.; Karppinen, M.

    2011-05-15

    Here we investigate the elemental and phase compositions during the solid-state synthesis of the promising SOFC-anode material, Sr{sub 2}MgMoO{sub 6}, and demonstrate that molybdenum does not notably evaporate under the normal synthesis conditions with temperatures up to 1200 {sup o}C due to the formation of SrMoO{sub 4} as an intermediate product at low temperatures, below 600 {sup o}C. However, partial decomposition of the Sr{sub 2}MgMoO{sub 6} phase becomes evident at the higher temperatures ({approx}1500 {sup o}C). The effect of SrMoO{sub 4} on the electrical conductivity of Sr{sub 2}MgMoO{sub 6} is evaluated by preparing a series of Sr{sub 2}MgMoO{sub 6} samples with different amounts of additional SrMoO{sub 4}. Under the reducing operation conditions of an SOFC anode the insulating SrMoO{sub 4} phase is apparently reduced to the highly conductive SrMoO{sub 3} phase. Percolation takes place with 20-30 wt% of SrMoO{sub 4} in a Sr{sub 2}MgMoO{sub 6} matrix, with a notable increase in electrical conductivity after reduction. Conductivity values of 14, 60 and 160 S/cm are determined at 800 {sup o}C in 5% H{sub 2}/Ar for the Sr{sub 2}MgMoO{sub 6} samples with 30, 40 and 50 wt% of added SrMoO{sub 4}, respectively. -- Graphical abstract: SrMoO{sub 4} is formed at low temperatures during the synthesis of Sr{sub 2}MgMoO{sub 6}, which prevents the volatilization of Mo from typical precursor mixtures of this promising SOFC anode material. SrMoO{sub 4} is insulating and it is often found as an impurity in Sr{sub 2}MgMoO{sub 6} samples. It is however readily reduced to highly conducting SrMoO{sub 3}. Composites of Sr{sub 2}MgMoO{sub 6} and SrMoO{sub 3} show increased electrical conductivities compared to pure Sr{sub 2}MgMoO{sub 6} under the reductive operation conditions of an SOFC anode. Display Omitted Highlights: {yields} Sr{sub 2}MgMoO{sub 6} is a promising SOFC anode material. {yields} During the Sr{sub 2}MgMoO{sub 6} synthesis SrMoO{sub 4} is formed at low temperatures. {yields} Formation of SrMoO{sub 4} effectively prevents volatilization of Mo at high temperatures. {yields} Insulating SrMoO{sub 4} reduces to highly conductive SrMoO{sub 3} under SOFC-anode conditions. {yields} Composites of Sr{sub 2}MgMoO{sub 6} and SrMoO{sub 3} show high electrical conductivities.

  19. Comparative Toxicity of Combined Particle and Semi-Volatile Organic...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Toxicity of Combined Particle and Semi-Volatile Organic Fractioins of Gasoline and Diesel Emissions Comparative Toxicity of Combined Particle and Semi-Volatile Organic Fractioins ...

  20. Securing non-volatile memory regions

    DOE Patents [OSTI]

    Faraboschi, Paolo; Ranganathan, Parthasarathy; Muralimanohar, Naveen

    2013-08-20

    Methods, apparatus and articles of manufacture to secure non-volatile memory regions are disclosed. An example method disclosed herein comprises associating a first key pair and a second key pair different than the first key pair with a process, using the first key pair to secure a first region of a non-volatile memory for the process, and using the second key pair to secure a second region of the non-volatile memory for the same process, the second region being different than the first region.

  1. Modelling of volatility in monetary transmission mechanism

    SciTech Connect (OSTI)

    Dobešová, Anna; Klepáč, Václav; Kolman, Pavel; Bednářová, Petra

    2015-03-10

    The aim of this paper is to compare different approaches to modeling of volatility in monetary transmission mechanism. For this purpose we built time-varying parameter VAR (TVP-VAR) model with stochastic volatility and VAR-DCC-GARCH model with conditional variance. The data from three European countries are included in the analysis: the Czech Republic, Germany and Slovakia. Results show that VAR-DCC-GARCH system captures higher volatility of observed variables but main trends and detected breaks are generally identical in both approaches.

  2. Reactive flash volatilization of fluid fuels

    DOE Patents [OSTI]

    Schmidt, Lanny D.; Dauenhauer, Paul J.; Dreyer, Bradon J.; Salge, James R.

    2013-01-08

    The invention provides methods for the production of synthesis gas. More particularly, various embodiments of the invention relate to systems and methods for volatilizing fluid fuel to produce synthesis gas by using a metal catalyst on a solid support matrix.

  3. Partitioning of Volatile Organics in Diesel Particulate and Exhaust

    Broader source: Energy.gov [DOE]

    Evaluation of how sampling details affect the measurement of volatile organic compounds in diesel exhaust

  4. Volatility literature of chlorine, iodine, cesium, strontium, technetium,

    Office of Scientific and Technical Information (OSTI)

    and rhenium; technetium and rhenium volatility testing (Technical Report) | SciTech Connect Volatility literature of chlorine, iodine, cesium, strontium, technetium, and rhenium; technetium and rhenium volatility testing Citation Details In-Document Search Title: Volatility literature of chlorine, iodine, cesium, strontium, technetium, and rhenium; technetium and rhenium volatility testing × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a

  5. Experimental studies and thermodynamic modelling of volatilities of uranium, plutonium, and americium from their oxides and from their oxides interacted with ash

    SciTech Connect (OSTI)

    Krikorian, O.H.; Ebbinghaus, B.B.; Adamson, M.G.; Fontes, A.S. Jr.; Fleming, D.L.

    1993-09-15

    The purpose of this study is to identify the types and amounts of volatile gaseous species of U, Pu, and Am that are produced in the combustion chamber offgases of mixed waste oxidation processors. Primary emphasis is on the Rocky Flats Plant Fluidized Bed Incinerator. Transpiration experiments have been carried out on U{sub 3}O{sub 8}(s), U{sub 3}O{sub 8} interacted with various ash materials, PuO{sub 2}(s), PuO{sub 2} interacted with ash materials, and a 3%PuO{sub 2}/0.06%AmO{sub 2}/ash material, all in the presence of steam and oxygen, and at temperatures in the vicinity of 1,300 K. UO{sub 3}(g) and UO{sub 2}(OH){sub 2}(g) have been identified as the uranium volatile species and thermodynamic data established for them. Pu and Am are found to have very low volatilities, and carryover of Pu and Am as fine dust particulates is found to dominate over vapor transport. The authors are able to set upper limits on Pu and Am volatilities. Very little lowering of U volatility is found for U{sub 3}O{sub 8} interacted with typical ashes. However, ashes high in Na{sub 2}O (6.4 wt %) or in CaO (25 wt %) showed about an order of magnitude reduction in U volatility. Thermodynamic modeling studies were carried out that show that for aluminosilicate ash materials, it is the presence of group I and group II oxides that reduces the activity of the actinide oxides. K{sub 2}O is the most effective followed by Na{sub 2}O and CaO for common ash constituents. A more major effect in actinide activity lowering could be achieved by adding excess group I or group II oxides to exceed their interaction with the ash and lead to direct formation of alkali or alkaline earth uranates, plutonates, and americates.

  6. A new model for thermal volatilization of solid particles undergoing flash-pyrolysis

    SciTech Connect (OSTI)

    Villermaux, J.; Antoine, B.; Lede, J.; Soulignac, F.

    1983-01-01

    The authors propose a new model describing the volatilization of a solid by thermal penetration (VTP model). This model was initially imagined for interpreting flash-pyrolysis of sawdust particles. Actually, it could be applied to any kind of solid reactions where volatilization is controlled by heat conduction from the outer surface. Although relying on very simple assumptions, the VTP model makes it possible to estimate the rate of consumption of solid particles as a function of physicochemical parameters. Evidence for the existence of two volatilization regimes is provided, depending on the value of the thermal Thiele Modulus M and the thermal Biot number B. The ablation regime is achieved if both M = t /SUB T/ /t /SUB R/ and B = hL /SUB o/ /lambda are large (M, B > 100). In this regime, the shrinking velocity is constant and the reaction takes place only in a thin layer at the solid surface. Experimental data on wood pyrolysis obtained with sawdust or with massive rods confirm the existence of these two regimes (see companion paper). Total consumption times estimated in a cyclone reactor or direct measurement of ablation velocities are in agreement with theoretical predictions of the VPT model. These preliminary results have been obtained with very simple numerical methods which are not best adapted to the ''stiff'' conditions encountered in the ablation regime (M and B both large). Further improvements are in progress, which will make it possible to perform more accurate simulations in a broader range of variation of parameters.

  7. Volatile Species Retention During Metallic Fuel Casting

    SciTech Connect (OSTI)

    Randall S. Fielding; Douglas L. Proter

    2013-10-01

    Metallic nuclear fuels are candidate transmutation fuel forms for advanced fuel cycles. Through the operation of the Experimental Breeder Reactor II metallic nuclear fuels have been shown to be robust and easily manufactured. However, concerns have been raised concerning loss of americium during the casting process because of its high vapor pressure. In order to address these concerns a gaseous diffusion model was developed and a series of experiments using both manganese and samarium as surrogates for americium were conducted. The modeling results showed that volatility losses can be controlled to essentially no losses with a modest overpressure. Experimental results also showed volatile species retention down to no detectable losses through overpressure, although the loss values varied from the model results the same trend was seen. Bases on these results it is very probably that americium losses through volatility can be controlled to no detectable losses through application of a modest overpressure during casting.

  8. Non-volatile memory for checkpoint storage

    DOE Patents [OSTI]

    Blumrich, Matthias A.; Chen, Dong; Cipolla, Thomas M.; Coteus, Paul W.; Gara, Alan; Heidelberger, Philip; Jeanson, Mark J.; Kopcsay, Gerard V.; Ohmacht, Martin; Takken, Todd E.

    2014-07-22

    A system, method and computer program product for supporting system initiated checkpoints in high performance parallel computing systems and storing of checkpoint data to a non-volatile memory storage device. The system and method generates selective control signals to perform checkpointing of system related data in presence of messaging activity associated with a user application running at the node. The checkpointing is initiated by the system such that checkpoint data of a plurality of network nodes may be obtained even in the presence of user applications running on highly parallel computers that include ongoing user messaging activity. In one embodiment, the non-volatile memory is a pluggable flash memory card.

  9. Remarkably robust and correlated coherence and antiferromagnetism in (Ce<sub>1-xsub>Lax)Cu>2sub>Ge>2sub>

    SciTech Connect (OSTI)

    Hodovanets, H.; Budko, S. L.; Straszheim, W. E.; Taufour, V.; Mun, E. D.; Kim, H.; Flint, R.; Canfield, P. C.

    2015-06-08

    We present magnetic susceptibility, resistivity, specific heat, and thermoelectric power measurements on (Ce<sub>1-xsub>Lax)Cu>2sub>Ge>2sub> single crystals (0 ? x ? 1). With La-substitution, the antiferromagnetic temperature T<sub>N> is suppressed in an almost linear fashion and moves below 0.36 K, the base temperature of our measurements for x > 0.8. Surprisingly, in addition to robust antiferromagnetism, the system also shows low temperature coherent scattering below T<sub>coh> up to ~0.9 of La, indicating a small percolation limit ~9% of Ce. T<sub>coh> as a function of magnetic field was found to have different behavior for x < 0.9 and x > 0.9. Remarkably, (T<sub>coh>)2 at H = 0 was found to be linearly proportional to T<sub>N>. In conclusion, the jump in the magnetic specific heat ?C<sub>m> at T<sub>N> as a function of T<sub>K/TN> for (Ce<sub>1-xsub>Lax)Cu>2sub>Ge>2sub> follows the theoretical prediction based on the molecular field calculation for the S = 1/2 resonant level model.

  10. Development of very high J<sub>c> in Ba(Fe<sub>1-xsub>Cox)>2sub>As>2sub> thin films grown on CaF<sub>2sub>

    SciTech Connect (OSTI)

    Tarantini, C.; Kametani, F.; Lee, S.; Jiang, J.; Weiss, J. D.; Jaroszynski, J.; Hellstrom, E. E.; Eom, C. B.; Larbalestier, D. C.

    2014-12-03

    Ba(Fe<sub>1-xsub>Cox)>2sub>As>2sub> is the most tunable of the Fe-based superconductors (FBS) in terms of acceptance of high densities of self-assembled and artificially introduced pinning centres which are effective in significantly increasing the critical current density, J<sub>c>. Moreover, FBS are very sensitive to strain, which induces an important enhancement in critical temperature,T<sub>c>, of the material. In this study we demonstrate that strain induced by the substrate can further improve J<sub>c> of both single and multilayer films by more than that expected simply due to the increase in T<sub>c>. The multilayer deposition of Ba(Fe<sub>1-xsub>Cox)>2sub>As>2sub> on CaF<sub>2sub> increases the pinning force density (F<sub>p=Jc> x μ₀H) by more than 60% compared to a single layer film, reaching a maximum of 84 GN/m3 at 22.5 T and 4.2 K, the highest value ever reported in any 122 phase.

  11. Thermal Stabilization of {sup 233}UO{sub 2}, {sup 233}UO{sub 3}, and {sup 233}U{sub 3}O{sub 8}

    SciTech Connect (OSTI)

    Thein, S.M.

    2000-07-26

    This report identifies an appropriate thermal stabilization temperature for {sup 233}U oxides. The temperature is chosen principally on the basis of eliminating moisture and other residual volatiles. This report supports the U. S. Department of Energy (DOE) Standard for safe storage of {sup 233}U (DOE 2000), written as part of the response to Recommendation 97-1 of the Defense Nuclear Facilities Safety Board (DNFSB), addressing safe storage of {sup 233}U. The primary goals in choosing a stabilization temperature are (1) to ensure that the residual volatiles content is less than 0.5 wt % including moisture, which might produce pressurizing gases via radiolysis during long-term sealed storage; (2) to minimize potential for water readsorption above the 0.5 wt % threshold; and (3) to eliminate reactive uranium species. The secondary goals are (1) to reduce potential future chemical reactivity and (2) to increase the particle size thereby reducing the potential airborne release fraction (ARF) under postulated accident scenarios. The prevalent species of uranium oxide are the chemical forms UO{sub 2}, UO{sub 3}, and U{sub 3}O{sub 8}. Conversion to U{sub 3}O{sub 8} is sufficient to accomplish all of the desired goals. The preferred storage form is U{sub 3}O{sub 8} because it is more stable than UO{sub 2} or UO{sub 3} in oxidizing atmospheres. Heating in an oxidizing atmosphere at 750 C for at least one hour will achieve the thermal stabilization desired.

  12. Proboscis extension reflex platform for volatiles and semi-volatiles detection

    DOE Patents [OSTI]

    Wingo, Robert M.; McCabe, Kirsten J.; Haarmann, Timothy K.

    2010-11-30

    The present invention provides an apparatus for the detection of volatile and semi-volatile chemicals using the olfactory abilities of honey bees that are trained to respond to the presence of a specific chemical in a sample of gas with the proboscis extension reflex (PER). In particular, the geometry and arrangement of the parts of the apparatus are such that the amount of surface area in contact with the sample of gas prior to its introduction to the bees is minimized to improve the detection of particular volatile and semi-volatile that have a tendency to "stick" to contacting surfaces, especially certain chemicals associated with explosives and narcotics. According to another aspect of the present invention, a pre-concentrating means is incorporated with the device to effectively increase the concentration of "sticky" chemicals presented to the insects.

  13. Extended Research on Detection of Deception Using Volatile Organic...

    Office of Scientific and Technical Information (OSTI)

    Language: English Subject: 98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION; CENTRAL NERVOUS SYSTEM; DETECTION; ORGANIC COMPOUNDS; TESTING; VOLATILE MATTER deception, ...

  14. Structure symmetry determination and magnetic evolution in Sr<sub>2sub>Ir>1–xsub>RhxO>4sub>

    SciTech Connect (OSTI)

    Ye, Feng; Wang, Xiaoping; Hoffmann, Christina; Wang, Jinchen; Chi, Songxue; Matsuda, Masaaki; Chakoumakos, Bryan C.; Fernandez-Baca, Jaime A.; Cao, Gang

    2015-11-23

    We use single-crystal neutron diffraction to determine the crystal structure symmetry and to study the magnetic evolution in the rhodium doped iridates Sr<sub>2sub>Ir>1–xsub>RhxO>4sub> (0 ≤ x ≤ 0.16). Throughout this doping range, the crystal structure retains a tetragonal symmetry (space group I4<sub>1sub>/a) with two distinct magnetic Ir sites in the unit cell forming staggered IrO<sub>6sub> rotation. Upon Rh doping, the magnetic order is suppressed and the magnetic moment of Ir4+ is reduced from 0.21 μ<sub>B>/Ir for x = 0 to 0.18 μ<sub>B>/Ir for x = 0.12. As a result, the magnetic structure at x = 0.12 is different from that of the parent compound while the moments remain in the basal plane.

  15. Partitioning of Volatile Organics in Diesel Particulate and Exhaust...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Evaluation of how sampling details affect the measurement of volatile organic compounds in ... Identification of the Soluble Organic Fraction of Particulate Matter on DPF ...

  16. Volatiles in hydrothermal fluids- A mass spectrometric study...

    Open Energy Info (EERE)

    Volatiles in hydrothermal fluids- A mass spectrometric study of fluid inclusions from active geothermal systems Jump to: navigation, search OpenEI Reference LibraryAdd to library...

  17. Rhenium volatilization in waste glasses (Journal Article) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Rhenium volatilization in waste glasses Citation Details In-Document ... OSTI Identifier: 1252517 Type: Publisher's Accepted Manuscript Journal Name: Journal of ...

  18. Princeton and PPPL launch center to study volatile space weather...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Princeton and PPPL launch center to study volatile space weather and violent solar storms ... - a complex and frequently violent region of space that encompasses the solar system. ...

  19. Analysis of Price Volatility in Natural Gas Markets

    Reports and Publications (EIA)

    2007-01-01

    This article presents an analysis of price volatility in the spot natural gas market, with particular emphasis on the Henry Hub in Louisiana.

  20. Reducing volatilization of heavy metals in phosphate-pretreated...

    Office of Scientific and Technical Information (OSTI)

    The results showed that the volatilization behavior in phosphate-pretreated MSWI fly ash ... Resource Type: Journal Article Resource Relation: Journal Name: Waste Management; Journal ...

  1. Emission of volatile sulfur compounds during composting of municipal solid waste (MSW)

    SciTech Connect (OSTI)

    Zhang, Hongyu; Schuchardt, Frank; Li, Guoxue; Yang, Jinbing; Yang, Qingyuan

    2013-04-15

    Highlights: ? We compare the volatile sulfur compounds (VSCs) emissions during three types of municipal solid wastes (MSWs) composting. ? The VSCs released from the kitchen waste composting was significantly higher than that from 1580 mm fraction of MSW. ? Among the five VSCs, H{sub 2}S was the most abundant compound with 39.043.0% of total VSCs released. ? Addition of 20% cornstalks could significantly reduce the VSCs emissions during kitchen waste composting. - Abstract: Volatile sulfur compounds (VSCs) are the main source for malodor from composting plants. In this study, the VSCs generated from composting of 1580 mm municipal solid waste (T0), kitchen waste (T1) and kitchen waste mixed dry cornstalks (T2) were measured in 60 L reactors with forced aeration for a period of 30 days. The VSCs detected in all treatments were hydrogen sulfide (H{sub 2}S), methyl mercaptan (MM), dimethyl sulfide (DMS), carbon bisulfide (CS{sub 2}) and dimethyl disulfide (DMDS). Over 90% of the VSCs emissions occurred during the first 15 days, and reached their peak values at days 47. The emission profiles of five VSCs species were significantly correlated with internal materials temperature and outlet O{sub 2} concentration (p < 0.05). Total emissions of the VSCs were 216.1, 379.3 and 126.0 mg kg{sup ?1} (dry matter) for T0, T1 and T2, respectively. Among the five VSCs, H{sub 2}S was the most abundant compound with 39.043.0% of total VSCs released. Composting of kitchen waste from separate collection posed a negative influence on the VSC and leachate production because of its high moisture content. An addition of dry cornstalks at a mixing ratio of 4:1 (wet weight) could significantly reduce the VSCs emissions and avoid leachate. Compared to pure kitchen waste, VSCs were reduced 66.8%.

  2. Agency Sub-

    Energy Savers [EERE]

    February 2015 Agency Sub- agency Title Of Initiative/Rule or ICR RIN/OMB Control Number Summary of Initiative Status of Initiative -- New to this update, Ongoing, or Completed Target Completion Date (if completed, please add the publication date and cite in Federal Register for example) Does the Initiative include regulatory flexibilities such as pilot projects, safe harbor exemptions, sunset provisions, trigger provisions, streamlined requirements, state flexibilities, or other similar

  3. Agency Sub-

    Energy Savers [EERE]

    July 2015 Agency Sub- agency Title Of Initiative/Rule or ICR RIN/OMB Control Number Summary of Initiative Status of Initiative -- New to this update, Ongoing, or Completed Target Completion Date (if completed, please add the publication date and cite in Federal Register for example) Does the Initiative include regulatory flexibilities such as pilot projects, safe harbor exemptions, sunset provisions, trigger provisions, streamlined requirements, state flexibilities, or other similar strategies?

  4. Agency Sub-

    Energy Savers [EERE]

    Report as of March 2016 Agency Sub- agency Title Of Initiative/Rule or ICR RIN/OMB Control Number Summary of Initiative Status of Initiative -- New to this update, Ongoing, or Completed Target Completion Date (if completed, please add the publication date and cite in Federal Register for example) Does the Initiative include regulatory flexibilities such as pilot projects, safe harbor exemptions, sunset provisions, trigger provisions, streamlined requirements, state flexibilities, or other

  5. GeO{sub 2}/Ge structure submitted to annealing in deuterium: Incorporation pathways and associated oxide modifications

    SciTech Connect (OSTI)

    Bom, N. M.; Soares, G. V.; Hartmann, S.; Bordin, A.; Radtke, C.

    2014-10-06

    Deuterium (D) incorporation in GeO{sub 2}/Ge structures following D{sub 2} annealing was investigated. Higher D concentrations were obtained for GeO{sub 2}/Ge samples in comparison to their SiO{sub 2}/Si counterparts annealed in the same conditions. Oxygen vacancies produced during the annealing step in D{sub 2} constitute defect sites for D incorporation, analogous to defects at the SiO{sub 2}/Si interfacial region. Besides D incorporation, volatilization of the oxide layer is also observed as a consequence of D{sub 2} annealing, especially in the high temperature regime of the present study (>450?C). In parallel to this volatilization, the stoichiometry and chemical structure of remnant oxide are modified as well. These results evidence the broader impact of forming gas annealing in dielectric/Ge structures with respect to SiO{sub 2}/Si counterparts.

  6. WRF-Chem model predictions of the regional impacts of N<sub>2sub>O>5sub> heterogeneous processes on night-time chemistry over north-western Europe

    SciTech Connect (OSTI)

    Lowe, Douglas; Archer-Nicholls, Scott; Morgan, Will; Allan, James D.; Utembe, Steve; Ouyang, Bin; Aruffo, Eleonora; Le Breton, Michael; Zaveri, Rahul A.; di Carlo, Piero; Percival, Carl; Coe, H.; Jones, Roderic L.; McFiggans, Gordon

    2015-02-09

    Chemical modelling studies have been conducted over north-western Europe in summer conditions, showing that night-time dinitrogen pentoxide (N<sub>2sub>O>5sub>) heterogeneous reactive uptake is important regionally in modulating particulate nitrate and has a~modest influence on oxidative chemistry. Results from Weather Research and Forecasting model with Chemistry (WRF-Chem) model simulations, run with a detailed volatile organic compound (VOC) gas-phase chemistry scheme and the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) sectional aerosol scheme, were compared with a series of airborne gas and particulate measurements made over the UK in July 2010. Modelled mixing ratios of key gas-phase species were reasonably accurate (correlations with measurements of 0.70.9 for NO<sub>2sub> and O<sub>3sub>). However modelled loadings of particulate species were less accurate (correlation with measurements for particulate sulfate and ammonium were between 0.0 and 0.6). Sulfate mass loadings were particularly low (modelled means of 0.50.7 ?g kg?1<sub>air>, compared with measurements of 1.01.5 ?g kg?1<sub>air>). Two flights from the campaign were used as test cases one with low relative humidity (RH) (6070%), the other with high RH (8090%). N<sub>2sub>O>5sub> heterogeneous chemistry was found to not be important in the low-RH test case; but in the high-RH test case it had a strong effect and significantly improved the agreement between modelled and measured NO<sub>3sub> and N<sub>2sub>O>5sub>. When the model failed to capture atmospheric RH correctly, the modelled NO<sub>3sub> and N<sub>2sub>O>5sub> mixing ratios for these flights differed significantly from the measurements. This demonstrates that, for regional modelling which involves heterogeneous processes, it is essential to capture the ambient temperature and water vapour profiles.

    The night-time NO<sub>3sub> oxidation of VOCs across the whole region was found to be 100300 times slower than the daytime OH oxidation of these compounds. The difference in contribution was less for alkenes ( 80) and comparable for dimethylsulfide (DMS). However the suppression of NO<sub>3sub> mixing ratios across the domain by N<sub>2sub>O>5sub> heterogeneous chemistry has only a very slight, negative, influence on this oxidative capacity. The influence on regional particulate nitrate mass loadings is stronger. Night-time N<sub>2sub>O>5sub> heterogeneous chemistry maintains the production of particulate nitrate within polluted regions: when this process is taken into consideration, the daytime peak (for the 95th percentile) of PM<sub>10sub> nitrate mass loadings remains around 5.6 ?g kg?1<sub>air>, but the night-time minimum increases from 3.5 to 4.6 ?g kg?1<sub>air>. The sustaining of higher particulate mass loadings through the night by this process improves model skill at matching measured aerosol nitrate diurnal cycles and will negatively impact on regional air quality, requiring this process to be included in regional models.

  7. Infrared Spectroscopy of Wild 2 Particle Hypervelocity Tracks in Stardust Aerogel: Evidence for the presence of Volatile Organics in Comet Dust

    SciTech Connect (OSTI)

    Bajt, S; Sandford, S A; Flynn, G J; Matrajt, G; Snead, C J; Westphal, A J; Bradley, J P

    2007-08-28

    Infrared spectroscopy maps of some tracks, made by cometary dust from 81P/Wild 2 impacting Stardust aerogel, reveal an interesting distribution of volatile organic material. Out of six examined tracks three show presence of volatile organic components possibly injected into the aerogel during particle impacts. When particle tracks contained excess volatile organic material, they were found to be -CH{sub 2}-rich. Off-normal particle tracks could indicate impacts by lower velocity particles that could have bounced off the Whipple shield, therefore carry off some contamination from it. However, this theory is not supported by data that show excess organic-rich material in normal and off-normal particle tracks. It is clear that the population of cometary particles impacting the Stardust aerogel collectors also include grains that contained little or none of this volatile organic component. This observation is consistent with the highly heterogeneous nature of the collected grains, as seen by a multitude of other analytical techniques. We propose that at least some of the volatile organic material might be of cometary origin based on supporting data shown in this paper. However, we also acknowledge the presence of carbon (primarily as -CH{sub 3}) in the original aerogel, which complicates interpretation of these results.

  8. Hollow-fiber gas-membrane process for removal of NH{sub 3} from solution of NH{sub 3} and CO{sub 2}

    SciTech Connect (OSTI)

    Qin, Y.; Cabral, J.M.S.; Wang, S.

    1996-07-01

    A hollow-fiber supported gas membrane process for the separation of NH{sub 3} from aqueous solutions containing both NH{sub 3} and CO{sub 2} was investigated theoretically and experimentally. A lumen laminar flow and radial diffusion model was applied to calculate the membrane wall transfer coefficient from the data stripping a single volatile component, NH{sub 3} or CO{sub 2}, from their individual aqueous solutions. Influence of the type of membranes and operating conditions on mass-transfer rate were discussed, especially the influence of the membrane transfer coefficient on the film mass-transfer coefficient in the lumen. Appropriate configurations of the hollow-fiber modules for stripping of a single component were analyzed to optimize mass transfer. To predict the stripping of NH{sub 3} from a solution containing NH{sub 3} and CO{sub 2}, a mathematical model incorporating local chemical equilibria and Nernst-Planck diffusion was developed to describe the mass transport. The models described the experimental data fairly well. The experimental results showed that the supported gas membrane process can be used to remove NH{sub 3} effectively from aqueous media containing NH{sub 3} and CO{sub 2}.

  9. Plasma regenerated particulate trap and NO.sub.x reduction system

    DOE Patents [OSTI]

    Penetrante, Bernardino M.; Vogtlin, George E.; Merritt, Bernard T.; Brusasco, Raymond M.

    2000-01-01

    A non-catalytic two-stage process for removal of NO.sub.x and particulates from engine exhaust comprises a first stage that plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons, and a second stage, which preferably occurs simultaneously with the first stage, that converts NO.sub.2 and carbon soot particles to respective environmentally benign gases that include N.sub.2 and CO.sub.2. By preconverting NO to NO.sub.2 in the first stage, the efficiency of the second stage for NO.sub.x reduction is enhanced while carbon soot from trapped particulates is simultaneously converted to CO.sub.2 when reacting with the NO.sub.2 (that converts to N.sub.2). For example, an internal combustion engine exhaust is connected by a pipe to a chamber where carbon-containing particulates are electrostatically trapped or filtered and a non-thermal plasma converts NO to NO.sub.2 in the presence of O.sub.2 and hydrocarbons. Volatile hydrocarbons (C.sub.x H.sub.y) from the trapped particulates are oxidized in the plasma and the remaining soot from the particulates reacts with the NO.sub.2 to convert NO.sub.2 to N.sub.2, and the soot to CO.sub.2. The nitrogen exhaust components remain in the gas phase throughout the process, with no accompanying adsorption.

  10. Fragile structural transition in Mo<sub>3sub>Sb>7sub>

    SciTech Connect (OSTI)

    Yan, Jiaqiang -Q.; McGuire, Michael A; May, Andrew F; Parker, David S.; Mandrus, D. G.; Sales, Brian C.

    2015-08-10

    Mo<sub>3sub>Sb>7sub> single crystals lightly doped with Cr, Ru, or Te are studied in order to explore the interplay between superconductivity, magnetism, and the cubic-tetragonal structural transition. The structural transition at 53 K is extremely sensitive to Ru or Te substitution which introduces additional electrons, but robust against Cr substitution. We observed no sign of a structural transition in superconducting Mo<sub>2.91sub>Ru>0.09sub>Sb>7sub> and Mo<sub>3sub>Sb>6.975sub>Te>0.025sub>. In contrast, 3 at.% Cr doping only slightly suppresses the structural transition to 48 K while leaving no trace of superconductivity above 1.8 K. Analysis of magnetic properties suggests that the interdimer interaction in Mo<sub>3sub>Sb>7sub> is near a critical value and essential for the structural transition. Futhermore, all dopants suppress the superconductivity of Mo<sub>3sub>Sb>7sub>. The tetragonal structure is not necessary for superconductivity.

  11. Sub-to super-ambient temperature programmable microfabricated gas chromatography column

    DOE Patents [OSTI]

    Robinson, Alex L.; Anderson, Lawrence F.

    2004-03-16

    A sub- to super-ambient temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by combining a thermoelectric cooler and temperature sensing on the microfabricated column. Sub-ambient temperature programming enables the efficient separation of volatile organic compounds and super-ambient temperature programming enables the elution of less volatile analytes within a reasonable time. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

  12. Nitrogen Trifluoride-Based Fluoride- Volatility Separations Process: Initial Studies

    SciTech Connect (OSTI)

    McNamara, Bruce K.; Scheele, Randall D.; Casella, Andrew M.; Kozelisky, Anne E.

    2011-09-28

    This document describes the results of our investigations on the potential use of nitrogen trifluoride as the fluorinating and oxidizing agent in fluoride volatility-based used nuclear fuel reprocessing. The conceptual process uses differences in reaction temperatures between nitrogen trifluoride and fuel constituents that produce volatile fluorides to achieve separations and recover valuable constituents. We provide results from our thermodynamic evaluations, thermo-analytical experiments, kinetic models, and provide a preliminary process flowsheet. The evaluations found that nitrogen trifluoride can effectively produce volatile fluorides at different temperatures dependent on the fuel constituent.

  13. VOLATILE CHLORIDE PROCESS FOR THE RECOVERY OF METAL VALUES

    DOE Patents [OSTI]

    Hanley, W.R.

    1959-01-01

    A process is presented for recovering uranium, iron, and aluminum from centain shale type ores which contain uranium in minute quantities. The ore is heated wiih a chlorinating agent. such as chlorine, to form a volatilized stream of metal chlorides. The chloride stream is then passed through granular alumina which preferentially absorbs the volatile uranium chloride and from which the uranium may later be recovered. The remaining volatilized chlorides, chiefly those of iron and aluminum, are further treated to recover chlorine gas for recycle, and to recover ferric oxide and aluminum oxide as valuable by-products.

  14. Fe<sub>2sub>O>3sub>–TiO>2sub> core–shell nanorod arrays for visible light photocatalytic applications

    SciTech Connect (OSTI)

    Yao, Kun; Basnet, Pradip; Sessions, Henry; Larsen, George K.; Murph, Simona E. Hunyadi; Zhao, Yiping

    2015-11-11

    By using the glancing angle deposition technique and post-deposition annealing, Fe<sub>2sub>O>3sub>–TiO>2sub> core-shell nanorod arrays with specific crystalline states can be designed and fabricated. The Fe<sub>2sub>O>3sub>–TiO>2sub> core-shell samples annealed at temperatures greater than 450°C formed α-Fe<sub>2sub>O>3sub> and anatase TiO<sub>2sub>, and showed higher catalytic efficiency for the degradation of methylene blue (MB) under visible light illumination when compared with pure anatase TiO<sub>2sub> or α-Fe<sub>2sub>O>3sub> nanorod arrays. Solar conversion of carbon dioxide and water vapor in the presence of Fe<sub>2sub>O>3sub>–TiO>2sub> core-shell nanorod arrays was also investigated. Carbon monoxide, hydrogen, methane, and methanol along with other hydrocarbons were produced after only several hours’ exposure under ambient sunlight. It was determined that the core-shell structure showed greater efficiency for solar CO<sub>2sub> conversion than the pure TiO<sub>2sub> nanorod arrays.

  15. FDATMOS16 non-linear partitioning and organic volatility distributions...

    Office of Scientific and Technical Information (OSTI)

    These few available volatility distributions suggest that urban OA may be only slightly super-linear, with most values of the sensitivity exponent in the range 1.1-1.3, also ...

  16. In Vitro Genotoxicity of Particulate and Semi-Volatile Organic...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Organic Compound Exhaust Materails from a Set of Gasoline and a Set of Diesel Engine Vehicles Operated at 30F In Vitro Genotoxicity of Particulate and Semi-Volatile Organic ...

  17. Volatility of Vanadia from Vanadia-Based SCR Catalysts under...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Vanadia from Vanadia-Based SCR Catalysts under Accelerated Aging Conditions Volatility of Vanadia from Vanadia-Based SCR Catalysts under Accelerated Aging Conditions TiO2-supported ...

  18. Evaluation of Models for Solubility and Volatility of Copper Compounds

    Office of Scientific and Technical Information (OSTI)

    Under Steam Generation Conditions (Conference) | SciTech Connect Evaluation of Models for Solubility and Volatility of Copper Compounds Under Steam Generation Conditions Citation Details In-Document Search Title: Evaluation of Models for Solubility and Volatility of Copper Compounds Under Steam Generation Conditions The loss in efficiency of power plants with mixed metallurgy, due to transport and deposition of copper and its oxides in HP turbines, has been recognized as one of the key

  19. VOLATILE FLUORIDE PROCESS FOR SEPARATING PLUTONIUM FROM OTHER MATERIALS

    DOE Patents [OSTI]

    Spedding, F.H.; Newton, A.S.

    1959-04-14

    The separation of plutonium from uranium and/or tission products by formation of the higher fluorides of uranium and/or plutonium is discussed. Neutronirradiated uranium metal is first convcrted to the hydride. This hydrided product is then treatced with fluorine at about 315 deg C to form and volatilize UF/sup 6/ leaving plutonium behind. The plutonium may then be separated by reacting the residue with fluorine at about 500 deg C and collecting the volatile plutonium fluoride thus formed.

  20. Reducing volatilization of heavy metals in phosphate-pretreated municipal

    Office of Scientific and Technical Information (OSTI)

    solid waste incineration fly ash by forming pyromorphite-like minerals (Journal Article) | SciTech Connect Reducing volatilization of heavy metals in phosphate-pretreated municipal solid waste incineration fly ash by forming pyromorphite-like minerals Citation Details In-Document Search Title: Reducing volatilization of heavy metals in phosphate-pretreated municipal solid waste incineration fly ash by forming pyromorphite-like minerals This research investigated the feasibility of reducing

  1. Investigation of La<sub>xSr>1-xsub>CoyM>1-ysub>O>3-dsub> (M = Mn Fe) perovskite materials as thermochemical energy storage media.

    SciTech Connect (OSTI)

    Babiniec, Sean Michael; Ambrosini, Andrea; Coker, Eric Nicholas; Miller, James E.

    2015-06-23

    Materials in the La<sub>xSr>1–xsub>CoyMn>1–ysub>O>3–δsub> (LSCM) and La<sub>xSr>1–xsub>CoyFe>1–ysub>O>3–δsub> (LSCF) families are candidates for high-temperature thermochemical energy storage due to their facility for cyclic endothermic reduction and exothermic oxidation. A set of 16 LSCM and 21 LSCF compositions were synthesized by a modified Pechini method and characterized by powder X-ray diffraction and thermogravimetric analysis. All materials were found to be various symmetries of the perovskite phase. LSCM was indexed as tetragonal, cubic, rhombohedral, or orthorhombic as a function of increased lanthanum content. For LSCF, compositions containing low lanthanum content were indexed as cubic while materials with high lanthanum content were indexed as rhombohedral. An initial screening of redox activity was completed by thermogravimetric analysis for each composition. The top three compositions with the greatest recoverable redox capacity for each family were further characterized in equilibrium thermogravimetric experiments over a range of temperatures and oxygen partial pressures. As a result, these equilibrium experiments allowed the extraction of thermodynamic parameters for LSCM and LSCF compositions operated in thermochemical energy storage conditions.

  2. Electronic structure, irreversibility line and magnetoresistance of Cu<sub>0.3sub>Bi>2sub>Se>3sub> superconductor

    SciTech Connect (OSTI)

    Hemian, Yi; Gu, Genda; Chen, Chao -Yu; Sun, Xuan; Xie, Zhuo -Jin; Feng, Ya; Liang, Ai -Ji; Peng, Ying -Ying; He, Shao -Long; Zhao, Lin; Liu, Guo -Dong; Dong, Xiao -Li; Zhang, Jun; Chen, Chuang -Tian; Xu, Zu -Yan; Zhou, X. -J.

    2015-06-01

    Cu<sub>xBi>2sub>Se>3sub> is a superconductor that is a potential candidate for topological superconductors. We report our laser-based angle-resolved photoemission measurement on the electronic structure of the Cu<sub>xBi>2sub>Se>3sub> superconductor, and a detailed magneto-resistance measurement in both normal and superconducting states. We find that the topological surface state of the pristine Bi<sub>2sub>Se>3sub> topological insulator remains robust after the Cu-intercalation, while the Dirac cone location moves downward due to electron doping. Detailed measurements on the magnetic field-dependence of the resistance in the superconducting state establishes an irreversibility line and gives a value of the upper critical field at zero temperature of ~4000 Oe for the Cu<sub>0.3sub>Bi>2sub>Se>3sub> superconductor with a middle point T<sub>c> of 1.9K. The relation between the upper critical field Hc2 and temperature T is different from the usual scaling relation found in cuprates and in other kinds of superconductors. Small positive magneto-resistance is observed in Cu<sub>0.3sub>Bi>2sub>Se>3sub> superconductors up to room temperature. As a result, these observations provide useful information for further study of this possible candidate for topological superconductors.

  3. Discovery of a metastable Al<sub>20sub>Sm>4sub> phase

    SciTech Connect (OSTI)

    Ye, Z.; Zhang, F.; Sun, Y.; Mendelev, M. I.; Ott, R. T.; Park, E.; Besser, M. F.; Kramer, M. J.; Ding, Z.; Wang, C. -Z.; Ho, K. -M.

    2015-03-09

    In this study, we present an efficient genetic algorithm, integrated with experimental diffraction data, to solve a nanoscale metastable Al<sub>20sub>Sm>4sub> phase that evolves during crystallization of an amorphous magnetron sputtered Al<sub>90sub>Sm>10sub> alloy. The excellent match between calculated and experimental X-ray diffraction patterns confirms an accurate description of this metastable phase. Molecular dynamic simulations of crystal growth from the liquid phase predict the formation of disordered defects in the devitrified crystal.

  4. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    SciTech Connect (OSTI)

    John F. Schabron; Joseph F. Rovani, Jr.; Theresa M. Bomstad

    2003-07-01

    Western Research Institute (WRI) is continuing work toward the development of new screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of halogens. In prior work, the devices were tested for response to carbon tetrachloride, heptane, toluene, and water vapors. In the current work, sensor response was evaluated with sixteen halogenated VOCs relative to carbon tetrachloride. The results show that the response of the various chlorinated VOCs is within an order of magnitude of the response to carbon tetrachloride for each of the sensors. Thus, for field screening a single response factor can be used. Both types of leak detectors are being further modified to provide an on-board LCD signal readout, which is related to VOC concentration. The units will be fully portable and will operate with 115-V line or battery power. Signal background, noise level, and response data on the Bacharach heated diode detector and the TIF corona discharge detector show that when the response curves are plotted against the log of concentration, the plot is linear to the upper limit for the particular unit, with some curvature at lower levels. When response is plotted directly against concentration, the response is linear at the low end and is curved at the high end. The dynamic ranges for carbon tetrachloride of the two devices from the lower detection limit (S/N=2) to signal saturation are 4-850 vapor parts per million (vppm) for the corona discharge unit and 0.01-70 vppm for the heated diode unit. Additional circuit modifications are being made to lower the detection limit and increase the dynamic response range of the corona discharge unit. The results indicate that both devices show potential utility for future analytical method development work toward the goal of developing a portable test kit for screening halogenated VOCs in the field.

  5. Superconductivity in strong spin orbital coupling compound Sb<sub>2sub>Se>3sub>

    SciTech Connect (OSTI)

    Kong, P. P.; Sun, F.; Xing, L. Y.; Zhu, J.; Zhang, S. J.; Li, W. M.; Liu, Q. Q.; Wang, X. C.; Feng, S. M.; Yu, X. H.; Zhu, J. L.; Yu, R. C.; Yang, W. G.; Shen, G. Y.; Zhao, Y. S.; Ahuja, R.; Mao, H. K.; Jin, C. Q.

    2014-10-20

    Recently, A<sub>2sub>B>3sub> type strong spin orbital coupling compounds such as Bi<sub>2sub>Te>3sub>, Bi<sub>2sub>Se>3sub> and Sb<sub>2sub>Te>3sub> were theoretically predicated to be topological insulators and demonstrated through experimental efforts. The counterpart compound Sb<sub>2sub>Se>3sub> on the other hand was found to be topological trivial, but theoretical studies indicated that the pressure might induce Sb<sub>2sub>Se>3sub> into a topological nontrivial state. We report on the discovery of superconductivity in Sb<sub>2sub>Se>3sub> single crystal induced via pressure. Our experiments indicated that Sb<sub>2sub>Se>3sub> became superconductive at high pressures above 10 GPa proceeded by a pressure induced insulator to metal like transition at ~3 GPa which should be related to the topological quantum transition. The superconducting transition temperature (T<sub>C>) increased to around 8.0 K with pressure up to 40 GPa while it keeps ambient structure. As a result, high pressure Raman revealed that new modes appeared around 10 GPa and 20 GPa, respectively, which correspond to occurrence of superconductivity and to the change of T<sub>C> slop as the function of high pressure in conjunction with the evolutions of structural parameters at high pressures.

  6. CO{sub 2} Sequestration Potential of Charqueadas Coal Field in Brazil

    SciTech Connect (OSTI)

    Romanov, V

    2012-10-23

    The I2B coal seam in the Charqueadas coal field has been evaluated as a target for enhanced coal bed methane production and CO{sub 2} sequestration. The samples were low rank coals (high volatile bituminous and sub-bituminous) obtained from the I2B seam as �3� cores. Such properties as sorption capacity, internal structure of the samples, porosity and permeability were of primary interest in this characterization study.

  7. Magnetic structures of R<sub>5sub>Ni>2sub>In>4sub> and R<sub>11sub>Ni>4sub>In>9sub> ( R = Tb and Ho): Strong hierarchy in the temperature dependence of the magnetic ordering in the multiple rare-earth sublattices

    SciTech Connect (OSTI)

    Ritter, C.; Provino, A.; Manfrinetti, P.; Pecharsky, V. K.; Gschneidner, Jr., K. A.; Dhar, S. K.

    2015-11-09

    In this study, the magnetic properties and magnetic structures of the R<sub>5sub>Ni>2sub>In>4sub> and the microfibrous R <sub>11sub>Ni>4sub>In>9sub> compounds with R = Tb and Ho have been examined using magnetization, heat capacity, and neutron diffraction data. Rare earth atoms occupy three and five symmetrically inequivalent rare earth sites in R<sub>5sub>Ni>2sub>In>4sub> and R <sub>11sub>Ni>4sub>In>9sub> compounds, respectively. As a result of the intra- and inter-magnetic sublattice interactions, the magnetic exchange interactions are different for various rare earth sites; this leads to a cascade of magnetic transitions with a strong hierarchy in the temperature dependence of the magnetic orderings.

  8. Structural and magnetic phase transitions near optimal superconductivity in BaFe<sub>2sub>(As>1-xsub>Px)>2sub>

    SciTech Connect (OSTI)

    Hu, Ding; Lu, Xingye; Zhang, Wenliang; Luo, Huiqian; Li, Shiliang; Wang, Peipei; Chen, Genfu; Han, Fei; Banjara, Shree R.; Sapkota, A.; Kreyssig, A.; Goldman, A. I.; Yamani, Z.; Niedermayer, Christof; Skoulatos, Markos; Georgii, Robert; Keller, T.; Wang, Pengshuai; Yu, Weiqiang; Dai, Pengcheng

    2015-04-17

    In this study, we use nuclear magnetic resonance (NMR), high-resolution x-ray and neutron scattering to study structural and magnetic phase transitions in phosphorus-doped BaFe<sub>2sub>(As>1-xsub>Px)>2sub>. Thus, previous transport, NMR, specific heat, and magnetic penetration depth measurements have provided compelling evidence for the presence of a quantum critical point (QCP) near optimal superconductivity at x = 0.3. However, we show that the tetragonal-to-orthorhombic structural (T<sub>s>) and paramagnetic to antiferromagnetic (AF, T<sub>N>) transitions in BaFe<sub>2sub>(As>1-xsub>Px)>2sub> are always coupled and approach to T<sub>N> ≈ T<sub>s> ≥ T<sub>c> (≈ 29 K) for x = 0.29 before vanishing abruptly for x ≥ 0.3. These results suggest that AF order in BaFe<sub>2sub>(As>1-xsub>Px)>2sub> disappears in a weakly first order fashion near optimal superconductivity, much like the electron-doped iron pnictides with an avoided QCP.

  9. Evolution of competing magnetic order in the J<sub>eff>=1/2 insulating state of Sr<sub>2sub>Ir>1-xsub>RuxO>4sub>

    SciTech Connect (OSTI)

    Calder, Stuart A.; Kim, Jong-Woo; Cao, Guixin; Cantoni, Claudia; May, Andrew F; Cao, Huibo B.; Aczel, Adam A.; Matsuda, Masaaki; Choi, Yongseong; Haskel, Daniel; Sales, B. C.; Mandrus, David; Lumsden, Mark D.; Christianson, Andrew D.

    2015-10-27

    We investigate the magnetic properties of the series Sr<sub>2sub>Ir>1-xsub>RuxO>4sub> with neutron, resonant x-ray and magnetization measurements. The results indicate an evolution and coexistence of magnetic structures via a spin flop transition from ab-plane to c-axis collinear order as the 5d Ir4+ ions are replaced with an increasing concentration of 4d Ru4+ ions. The magnetic structures within the ordered regime of the phase diagram (x<0.3) are reported. Despite the changes in magnetic structure no alteration of the J<sub>eff>=1/2 ground state is observed. This behavior of Sr<sub>2sub>Ir>1-xsub>RuxO>4sub> is consistent with electronic phase separation and diverges from a standard scenario of hole doping. The role of lattice alterations with doping on the magnetic and insulating behavior is considered. Our results presented here provide insight into the magnetic insulating states in strong spin-orbit coupled materials and the role perturbations play in altering the behavior.

  10. trans-K<sub>3sub>[TcO>2sub>(CN)>4sub>

    SciTech Connect (OSTI)

    Chatterjee, Sayandev; Del Negro, Andrew S; Edwards, Matthew K; Twamley, Brendan; Krause, Jeanette A; Bryan, Samuel A

    2010-07-14

    The dioxotetracyanotechnetate anion, [TcO<sub>2sub>(CN)>4sub>]3-, of the title complex has octahedral symmetry. The technetium is located on a center of inversion and is bound by two oxygen atoms and four cyano ligands. The Tc=O bond distance of 1.7721 (12) Å is consistent with double bond character. The potassium cations [located on special (1/2,0,1) and general positions] reside in octahedral or tetrahedral environments; interionic K···O and K···N interactions occur in the 2.7877 (19)-2.8598 (15) Å range.

  11. Gold-rich R<sub>3sub>Au>7sub>Sn>3sub>: Establishing the interdependence between electronic features and physical properties

    SciTech Connect (OSTI)

    Provino, Alessia; Steinberg, Simon; Smetana, Volodymyr; Kulkarni, Ruta; Dhar, Sudesh K.; Manfrinetti, Pietro; Mudring, Anja -Verena

    2015-05-18

    Two new polar intermetallic compounds Y<sub>3sub>Au>7sub>Sn>3sub> (I) and Gd<sub>3sub>Au>7sub>Sn>3sub> (II) have been synthesized and their structures have been determined by single crystal X-ray diffraction (P6<sub>3sub>/m; Z = 2, a = 8.148(1)/8.185(3), and c = 9.394(2)/9.415(3) for I/II, respectively). They can formally be assigned to the Cu<sub>10sub>Sn>3sub> type and consist of parallel slabs of Sn centered, edge-sharing trigonal Au<sub>6sub> antiprisms connected through R<sub>3sub> (R = Y, Gd) triangles. Additional Au atoms reside in the centres of trigonal Au<sub>6sub> prisms forming Au@Au<sub>6sub> clusters with Au–Au distances of 2.906–2.960 Å, while the R–R contacts in the R<sub>3sub> groups are considerably larger than the sums of their metallic radii. These exclusive structural arrangements provide alluring systems to study the synergism between strongly correlated systems, particularly, those in the structure of (II), and extensive polar intermetallic contacts, which has been inspected by measurements of the magnetic properties, heat capacities and electrical conductivities of both compounds. Gd<sub>3sub>Au>7sub>Sn>3sub> shows an antiferromagnetic ordering at 13 K, while Y<sub>3sub>Au>7sub>Sn>3sub> is a Pauli paramagnet and a downward curvature in its electrical resistivity at about 1.9 K points to a superconducting transition. DFT-based band structure calculations on R<sub>3sub>Au>7sub>Sn>3sub> (R = Y, Gd) account for the results of the conductivity measurements and different spin ordering models of (II) provide conclusive hints about its magnetic structure. As a result, chemical bonding analyses of both compounds indicate that the vast majority of bonding originates from the heteroatomic Au–Gd and Au–Sn interactions, while homoatomic Au–Au bonding is evident within the Au@Au<sub>6sub> clusters.

  12. Spin glass in semiconducting KFe<sub>1.05sub>Ag>0.88sub>Te>2sub> single crystals

    SciTech Connect (OSTI)

    Ryu, H.; Lei, H.; Klobes, B.; Warren, J. B.; Hermann, R. P.; Petrovic, C.

    2015-05-26

    We report discovery of KFe<sub>1.05sub>Ag>0.88sub>Te>2sub> single crystals with semiconducting spin glass ground state. Composition and structure analysis suggest nearly stoichiometric I4/mmm space group but allow for the existence of vacancies, absent in long range semiconducting antiferromagnet KFe<sub>1.05sub>Ag>0.88sub>Te>2sub>. The subtle change in stoichometry in Fe/Ag sublattice changes magnetic ground state but not conductivity, giving further insight into the semiconducting gap mechanism.

  13. Effect of neutron irradiation on defect evolution in Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC

    SciTech Connect (OSTI)

    Tallman, Darin J.; He, Lingfeng; Garcia-Diaz, Brenda L.; Hoffman, Elizabeth N.; Kohse, Gordon; Sindelar, Robert L.; Barsoum, Michel W.

    2015-10-23

    Here, we report on the characterization of defects formed in polycrystalline Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC samples exposed to neutron irradiation – up to 0.1 displacements per atom (dpa) at 350 ± 40 °C or 695 ± 25 °C, and up to 0.4 dpa at 350 ± 40 °C. Black spots are observed in both Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC after irradiation to both 0.1 and 0.4 dpa at 350 °C. After irradiation to 0.1 dpa at 695 °C, small basal dislocation loops, with a Burgers vector of b = 1/2 [0001] are observed in both materials. At 9 ± 3 and 10 ± 5 nm, the loop diameters in the Ti<sub>3sub>SiC>2sub> and Ti<sub>2sub>AlC samples, respectively, were comparable. At 1 × 1023 loops/m3, the dislocation loop density in Ti<sub>2sub>AlC was ≈1.5 orders of magnitude greater than in Ti<sub>3sub>SiC>2sub>, at 3 x 1021 loops/m3. After irradiation at 350 °C, extensive microcracking was observed in Ti<sub>2sub>AlC, but not in Ti<sub>3sub>SiC>2sub>. The room temperature electrical resistivities increased as a function of neutron dose for all samples tested, and appear to saturate in the case of Ti<sub>3sub>SiC>2sub>. The MAX phases are unequivocally more neutron radiation tolerant than the impurity phases TiC and Al<sub>2sub>O>3sub>. Based on these results, Ti<sub>3sub>SiC>2sub> appears to be a more promising MAX phase candidate for high temperature nuclear applications than Ti<sub>2sub>AlC.

  14. Melt Processed Single Phase Hollandite Waste Forms For Nuclear Waste Immobilization: Ba{sub 1.0}Cs{sub 0.3}A{sub 2.3}Ti{sub 5.7}O{sub 16}; A = Cr, Fe, Al

    SciTech Connect (OSTI)

    Brinkman, Kyle; Marra, James; Amoroso, Jake; Conradson, Steven D.; Tang, Ming

    2013-09-23

    Cs is one of the more problematic fission product radionuclides to immobilize due to its high volatility at elevated temperatures, ability to form water soluble compounds, and its mobility in many host materials. The hollandite structure is a promising crystalline host for Cs immobilization and has been traditionally fabricated by solid state sintering methods. This study presents the structure and performance of Ba{sub 1.0}Cs{sub 0.3}A{sub 2.3}Ti{sub 5.7}O{sub 16}; A = Cr, Fe, Al hollandite fabricated by melt processing. Melt processing is considered advantageous given that melters are currently in use for High Level Waste (HLW) vitrification in several countries. This work details the impact of Cr additions that were demonstrated to i) promote the formation of a Cs containing hollandite phase and ii) maintain the stability of the hollandite phase in reducing conditions anticipated for multiphase waste form processing.

  15. The magnetic structure of EuCu<sub>2sub>Sb>2sub>

    SciTech Connect (OSTI)

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu<sub>2sub>Sb>2sub> which forms in the tetragonal CaBe<sub>2sub>Ge>2sub>-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mössbauer spectroscopy. The room temperature 151Eu isomer shift of –12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (B<sub>hf>) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. B<sub>hf>(T) follows a smooth $S=\\frac{7}{2}$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) μ<sub>B> which is the full free-ion moment expected for the Eu2+ ion with $S=\\frac{7}{2}$ and a spectroscopic splitting factor of g = 2.

  16. The magnetic structure of EuCu<sub>2sub>Sb>2sub>

    SciTech Connect (OSTI)

    Ryan, D. H.; Cadogan, J. M.; Anand, V. K.; Johnston, D. C.; Flacau, R.

    2015-05-06

    Antiferromagnetic ordering of EuCu<sub>2sub>Sb>2sub> which forms in the tetragonal CaBe<sub>2sub>Ge>2sub>-type structure (space group P4/nmm #129) has been studied using neutron powder diffraction and 151Eu Mssbauer spectroscopy. The room temperature 151Eu isomer shift of 12.8(1) mm/s shows the Eu to be divalent, while the 151Eu hyperfine magnetic field (B<sub>hf>) reaches 28.7(2) T at 2.1 K, indicating a full Eu2+ magnetic moment. B<sub>hf>(T) follows a smooth $S=\\frac{7}{2}$ Brillouin function and yields an ordering temperature of 5.1(1) K. Refinement of the neutron diffraction data reveals a collinear A-type antiferromagnetic arrangement with the Eu moments perpendicular to the tetragonal c-axis. As a result, the refined Eu magnetic moment at 0.4 K is 7.08(15) ?<sub>B> which is the full free-ion moment expected for the Eu2+ ion with $S=\\frac{7}{2}$ and a spectroscopic splitting factor of g = 2.

  17. Magnetoelectric coupling tuned by competing single iron anisotropies in Mn<sub>1-xsub>NixTiO>3sub>

    SciTech Connect (OSTI)

    Chi, Songxue; Ye, Feng; Zhou, Haidong D.; Choi, E. S.; Hwang, J.; Cao, Huibo; Fernandez-Baca, Jaime A.

    2014-01-01

    A flop of electric polarization from P<sub>c> to P<sub>a> is observed in MnTiO<sub>3sub> as a spin flop transtion is triggered by a c-axis magnetic field, H<sub>c>=7 T. The critical magnetic field for P<sub>a> is significantly reduced in Mn<sub>1-xsub>NixTiO>3sub> (x=0.33). Neutron diffraction measurements revealed similar magnetic arrangements for the two compositions where the ordered spins couple antiferromagnetically with their nearest intra- and inter-planar neighbors. In the x=0.33 system, the single ion anisotropies of Mn2+ and Ni2+ compete and give rise to an additional spin reorientation transition at TR. A magnetic field, H<sub>c>, aligns the spins along c for T<sub>RN>. The rotation of the collinear spins away from the c-axis for Tsub>R> alters the magnetic point symmetry and gives rise to new ME susceptibility tensor form. Such linear ME response provides satisfactory explanation for behavior of field-induced electric polarization in both compositions. As the Ni content increases to x=0.5 and 0.68, the ME effect disappears as a new magnetic phase emerges.

  18. Cycling Endurance of SONOS Non-Volatile Memory Stacks Prepared with Nitrided SiO(2)/Si(100) Intefaces

    SciTech Connect (OSTI)

    Habermehl, S.; Nasby, R.D.; Rightley, M.J.

    1999-01-11

    The effects of nitrided SiO{sub 2}/Si(100) interfaces upon cycling endurance in silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile memory transistors are investigated. Analysis of MOSFET sub-threshold characteristics indicate cycling degradation to be a manifestation of interface state (D{sub it}) generation at the tunnel oxide/silicon interface. After 10{sup 6} write/erase cycles, SONOS film stacks prepared with nitrided tunnel oxides exhibit enhanced cycling endurance with {Delta}D{sub it}=3x10{sup 12} V{sup -1}cm{sup -2}, compared to {Delta}D{sub it}=2x10{sup 13} V{sup -l}cm{sup -2} for non-nitrided tunnel oxides. Additionally, if the capping oxide is formed by steam oxidation, rather than by deposition, SONOS stacks prepared with non-nitrided tunnel oxides exhibit endurance characteristics similar to stacks with nitrided tunnel oxides. From this observation it is concluded that latent nitridation of the tunnel oxidehilicon interface occurs during steam oxide cap formation.

  19. Synthesis, Structure, and Electrochemical Performance of High Capacity Li<sub>2sub>Cu>0.5sub>Ni>0.5sub>O>2sub> Cathodes

    SciTech Connect (OSTI)

    Ruther, Rose E; Zhou, Hui; Dhital, Chetan; Saravanan, Kuppan; Kercher, Andrew K.; Chen, Guoying; Huq, Ashfia; Delnick, Frank M.; Nanda, Jagjit

    2015-09-08

    Orthorhombic Li<sub>2sub>NiO>2sub>, Li<sub>2sub>CuO>2sub>, and solid solutions thereof have been studied as potential cathode materials for lithium-ion batteries due to their high theoretical capacity and relatively low cost. While neither endmember shows good cycling stability, the intermediate composition, Li<sub>2sub>Cu>0.5sub>Ni>0.5sub>O>2sub>, yields reasonably high reversible capacities. A new synthetic approach and detailed characterization of this phase and the parent Li<sub>2sub>CuO>2sub> are presented. The cycle life of Li<sub>2sub>Cu>0.5sub>Ni>0.5sub>O>2sub> is shown to depend critically on the voltage window. The formation of Cu1+ at low voltage and oxygen evolution at high voltage limit the electrochemical reversibility. In situ X-ray absorption spectroscopy (XAS), in situ Raman spectroscopy, and gas evolution measurements are used to follow the chemical and structural changes that occur as a function of cell voltage.

  20. Magnetic properties of bulk, and rapidly solidified nanostructured (Nd<sub>1-xsub>Cex)>2sub>Fe>14-ysub>Coy>B ribbons

    SciTech Connect (OSTI)

    Pathak, Arjun K.; Khan, M.; Gschneidner, Jr., K. A.; McCallum, R. W.; Zhou, L.; Sun, K.; Kramer, M. J.; Pecharsky, V. K.

    2015-11-06

    Magnetic properties of Ce and Co co-doped (Nd<sub>1-xsub>Cex)>2sub>Fe>14-ysub>Coy>B compounds have been investigated both in bulk polycrystalline and rapidly solidified nanostructured ribbon forms. For certain Ce concentrations the materials exhibit spin re-orientation transitions below 140 K. The Curie temperatures, saturation magnetizations, and other magnetic properties relevant for applications as permanent magnets are controlled by Ce and Co substitutions for Nd and Fe, respectively. Most importantly, the results show that Ce, Co co-doped compounds are excellent replacements for several Dy-based high performance permanent magnets (dysprosium is one of the critical elements and is, therefore, in short supply). As a result, the high temperature (>375 K) magnetic properties for Nd–Ce–Fe–Co–B based alloys show promise not only as a replacement for Dy-doped Nd<sub>2sub>Fe>14sub>B permanent magnets, but the new alloys also require significantly lower amounts of Nd, which too is the critical element that can be replaced by a more abundant Ce.

  1. Anisotropic swelling and microcracking of neutron irradiated Ti<sub>3sub>AlC>2sub>-Ti>5sub>Al>2sub>C>3sub> materials

    SciTech Connect (OSTI)

    Ang, Caen K.; Silva, Chinthaka M.; Shih, Chunghao Phillip; Koyanagi, Takaaki; Katoh, Yutai; Zinkle, Steven J.

    2015-12-17

    M<sub>n + 1sub>AXn> (MAX) phase materials based on Ti–Al–C have been irradiated at 400 °C (673 K) with fission neutrons to a fluence of 2 × 1025 n/m2 (E > 0.1 MeV), corresponding to ~ 2 displacements per atom (dpa). We report preliminary results of microcracking in the Al-containing MAX phase, which contained the phases Ti<sub>3sub>AlC>2sub> and Ti<sub>5sub>Al>2sub>C>3sub>. Equibiaxial ring-on-ring tests of irradiated coupons showed that samples retained 10% of pre-irradiated strength. Volumetric swelling of up to 4% was observed. Phase analysis and microscopy suggest that anisotropic lattice parameter swelling caused microcracking. Lastly, variants of titanium aluminum carbide may be unsuitable materials for irradiation at light water reactor-relevant temperatures.

  2. High-G testing of MEMS mechanical non-volatile memory and silicon...

    Office of Scientific and Technical Information (OSTI)

    High-G testing of MEMS mechanical non-volatile memory and silicon re-entry switch. Citation Details In-Document Search Title: High-G testing of MEMS mechanical non-volatile memory ...

  3. Polytypism, polymorphism, and superconductivity in TaSe<sub>2sub>–xTex>

    SciTech Connect (OSTI)

    Luo, Huixia; Xie, Weiwei; Tao, Jing; Inoue, Hiroyuki; Gyenis, András; Krizan, Jason W.; Yazdani, Ali; Zhu, Yimei; Cava, Robert Joseph

    2015-03-03

    Polymorphism in materials often leads to significantly different physical properties - the rutile and anatase polymorphs of TiO₂ are a prime example. Polytypism is a special type of polymorphism, occurring in layered materials when the geometry of a repeating structural layer is maintained but the layer stacking sequence of the overall crystal structure can be varied; SiC is an example of a material with many polytypes. Although polymorphs can have radically different physical properties, it is much rarer for polytypism to impact physical properties in a dramatic fashion. Here we study the effects of polytypism and polymorphism on the superconductivity of TaSe₂, one of the archetypal members of the large family of layered dichalcogenides. We show that it is possible to access 2 stable polytypes and 2 stable polymorphs in the TaSe<sub>2-xsub>Tex> solid solution, and find that the 3R polytype shows a superconducting transition temperature that is between 6 and 17 times higher than that of the much more commonly found 2H polytype. Thus, the reason for this dramatic change is not apparent, but we propose that it arises either from a remarkable dependence of T<sub>c> on subtle differences in the characteristics of the single layers present, or from a surprising effect of the layer stacking sequence on electronic properties that instead are expected to be dominated by the properties of a single layer in materials of this kind.

  4. Measurement of the B<sub>-c>meson lifetime in the decay B<sub>-c>?J/???

    SciTech Connect (OSTI)

    Aaltonen, T.; lvarez Gonzlez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bisello, D.; Bizjak, I.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Buzatu, A.; Calamba, A.; Calancha, C.; Camarda, S.; Campanelli, M.; Campbell, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Carron, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cavalli-Sforza, M.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Chlebana, F.; Cho, K.; Chokheli, D.; Chung, W. H.; Chung, Y. S.; Ciocci, M. A.; Clark, A.; Clarke, C.; Compostella, G.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Crescioli, F.; Cuevas, J.; Culbertson, R.; Dagenhart, D.; dAscenzo, N.; Datta, M.; de Barbaro, P.; DellOrso, M.; Demortier, L.; Deninno, M.; Devoto, F.; dErrico, M.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; DOnofrio, M.; Donati, S.; Dong, P.; Dorigo, M.; Dorigo, T.; Ebina, K.; Elagin, A.; Eppig, A.; Erbacher, R.; Errede, S.; Ershaidat, N.; Eusebi, R.; Farrington, S.; Feindt, M.; Fernandez, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Frank, M. J.; Franklin, M.; Freeman, J. C.; Funakoshi, Y.; Furic, I.; Gallinaro, M.; Garcia, J. E.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Giannetti, P.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Giurgiu, G.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Goldschmidt, N.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; Gonzlez, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Grinstein, S.; Grosso-Pilcher, C.; Group, R. C.; Guimaraes da Costa, J.; Hahn, S. R.; Halkiadakis, E.; Hamaguchi, A.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, D.; Hare, M.; Harr, R. F.; Hatakeyama, K.; Hays, C.; Heck, M.; Heinrich, J.; Herndon, M.; Hewamanage, S.; Hocker, A.; Hopkins, W.; Horn, D.; Hou, S.; Hughes, R. E.; Hurwitz, M.; Husemann, U.; Hussain, N.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Khotilovich, V.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. B.; Kim, S. H.; Kim, Y. K.; Kim, Y. J.; Kimura, N.; Kirby, M.; Klimenko, S.; Knoepfel, K.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Krop, D.; Kruse, M.; Krutelyov, V.; Kuhr, T.; Kurata, M.; Kwang, S.; Laasanen, A. T.; Lami, S.; Lammel, S.; Lancaster, M.; Lander, R. L.; Lannon, K.; Lath, A.; Latino, G.; LeCompte, T.; Lee, E.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lin, C.-J.; Lindgren, M.; Lipeles, E.; Lister, A.; Litvintsev, D. O.; Liu, C.; Liu, H.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maeshima, K.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Margaroli, F.; Marino, C.; Martnez, M.; Mastrandrea, P.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McFarland, K. S.; McIntyre, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondragon, M. N.; Moon, C. S.; Moore, R.; Morello, M. J.; Morlock, J.; Movilla Fernandez, P.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Neu, C.; Neubauer, M. S.; Nielsen, J.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Oksuzian, I.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagan Griso, S.; Pagliarone, C.; Palencia, E.; Papadimitriou, V.; Paramonov, A. A.; Patrick, J.; Pauletta, G.; Paulini, M.; Paus, C.; Pellett, D. E.; Penzo, A.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Prokoshin, F.; Pranko, A.; Ptohos, F.; Punzi, G.; Rahaman, A.; Ramakrishnan, V.; Ranjan, N.; Redondo, I.; Renton, P.; Rescigno, M.; Riddick, T.; Rimondi, F.; Ristori, L.; Robson, A.; Rodrigo, T.; Rodriguez, T.; Rogers, E.; Rolli, S.; Roser, R.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Safonov, A.; Sakumoto, W. K.

    2013-01-01

    The lifetime of the B<sub>-c> meson is measured using 272 exclusive B<sub>-c>?J/?(?????)?? decays reconstructed in data from proton-antiproton collisions corresponding to an integrated luminosity of 6.7 fb? recorded by the CDF II detector at the Fermilab Tevatron. The lifetime of the B<sub>-c>meson is measured to be <sub>?(B-c>)=0.4520.048(stat)0.027(syst) ps. This is the first measurement of the B<sub>-c> meson lifetime in a fully reconstructed hadronic channel, and it agrees with previous results and has comparable precision.

  5. Temperature dependence of the coercive force in Nd sub 4 Fe sub 77 B sub 19

    SciTech Connect (OSTI)

    Eckert, D.; Muller, K.H.; Handstein, A.; Schneider, J. ); Grossinger, R.; Krewenka, R. )

    1990-09-01

    The temperature dependence of coercivity {sub J}H{sub c} of Fe{sub 3}B-based Nd{sub 4}Fe{sub 77}B{sub 19} permanent magnetic materials is analysed. The coercivity of these melt-spun materials vanishes above the Curie temperature of the minor phase Nd{sub 2}Fe{sub 14}B. As well as melt-spun Nd-rich magnets, Nd{sub 4}Fe{sub 77}B{sub 19} magnets show a maximum in the {sub J}H{sub c} versus T curve at low temperatures. The coercivity of these melt-spun materials has a smaller temperature coefficient than sintered Nd-rich NdFeB magnets. The relation of the observed T- dependence of {sub J}H{sub c}, to the anisotropy field H{sub A}(T) of Nd{sub 2}Fe{sub 14}B is discussed.

  6. Analysis of the CO<sub>2sub>-H>2sub>O Chemisorption in Lithium Silicates at Low Temperatures (30-80 C)

    SciTech Connect (OSTI)

    Alcantar-Vazquez, Brenda; Pfeiffer, Heriberto; Daz Herrera, Pablo R.; Gonzalez, Alejandro Barrera; Duan, Yuhua

    2015-01-01

    Li<sub>8sub>SiO>6sub> and Li<sub>4sub>SiO>4sub> were synthesized by a solid-state reaction. Then, dynamic and isothermal thermogravimetric water vapor sorption experiments were performed using two carrier gases: N<sub>2sub> and CO<sub>2sub>. Initially, the Li<sub>8sub>SiO>6sub>-H>2sub>O-(N>2sub> or CO<sub>2sub>) systems were analyzed. It was evidenced that Li<sub>8sub>SiO>6sub> can trap water physically and chemically, producing Li-OH superficial species. When CO<sub>2sub> was used as the carrier gas, Li<sub>8sub>SiO>6sub> continued chemisorbing H<sub>2sub>O but CO<sub>2sub> was trapped as well, forming Li<sub>2sub>CO>3sub> and Li<sub>4sub>SiO>4sub> as secondary phases. On the basis of these results, the Li<sub>4sub>SiO>4sub>-H>2sub>O-CO>2sub> system was also analyzed. The experimental results and different theoretical thermodynamic calculations confirmed that Li<sub>8sub>SiO>6sub> can chemisorb 2 moles of CO<sub>2sub> per mole of ceramic at a low temperature range (30-80 C). Finally, different CO<sub>2sub> chemisorption kinetic experiments were performed to analyze and quantify the trapped CO<sub>2sub>.

  7. Method for refreshing a non-volatile memory

    DOE Patents [OSTI]

    Riekels, James E.; Schlesinger, Samuel

    2008-11-04

    A non-volatile memory and a method of refreshing a memory are described. The method includes allowing an external system to control refreshing operations within the memory. The memory may generate a refresh request signal and transmit the refresh request signal to the external system. When the external system finds an available time to process the refresh request, the external system acknowledges the refresh request and transmits a refresh acknowledge signal to the memory. The memory may also comprise a page register for reading and rewriting a data state back to the memory. The page register may comprise latches in lieu of supplemental non-volatile storage elements, thereby conserving real estate within the memory.

  8. High-Temperature Thermoelectric Properties of the Solid-Solution Zintl Phase Eu<sub>11sub>Cd>6sub>Sb>12-xsub>Asx> (x < 3)

    SciTech Connect (OSTI)

    Kazem, Nasrin; Xie, Weiwei; Ohno, Saneyuki; Zevalkink, Alexandra; Miller, Gordon J.; Snyder, G. Jeffrey; Kauzlarich, Susan M.

    2014-02-20

    Zintl phases are compounds that have shown promise for thermoelectric applications. The title solid–solution Zintl compounds were prepared from the elements as single crystals using a tin flux for compositions x = 0, 1, 2, and 3. Eu<sub>11sub>Cd>6sub>Sb>12–xsub>Asx> (x < 3) crystallize isostructurally in the centrosymmetric monoclinic space group C2/m (no. 12, Z = 2) as the Sr<sub>11sub>Cd>6sub>Sb>12sub> structure type (Pearson symbol mC58). Efforts to make the As compositions for x exceeding ~3 resulted in structures other than the Sr<sub>11sub>Cd>6sub>Sb>12sub> structure type. Single-crystal X-ray diffraction indicates that As does not randomly substitute for Sb in the structure but is site specific for each composition. The amount of As determined by structural refinement was verified by electron microprobe analysis. Electronic structures and energies calculated for various model structures of Eu<sub>11sub>Cd>6sub>Sb>10sub>As>2sub> (x = 2) indicated that the preferred As substitution pattern involves a mixture of three of the six pnicogen sites in the asymmetric unit. In addition, As substitution at the Pn4 site opens an energy gap at the Fermi level, whereas substitution at the other five pnicogen sites remains semimetallic with a pseudo gap. Thermoelectric properties of these compounds were measured on hot-pressed, fully densified pellets. Samples show exceptionally low lattice thermal conductivities from room temperature to 775 K: 0.78–0.49 W/mK for x = 0; 0.72–0.53 W/mK for x = 1; and 0.70–0.56 W/mK for x = 2. Eu<sub>11sub>Cd>6sub>Sb>12sub> shows a high p-type Seebeck coefficient (from +118 to 153 μ V/K) but also high electrical resistivity (6.8 to 12.8 mΩ·cm). The value of zT reaches 0.23 at 774 K. The properties of Eu<sub>11sub>Cd>6sub>Sb>12–xsub>Asx> are interpreted in discussion with the As site substitution.

  9. Highly dispersed SiO<sub>x/Al>2sub>O>3sub> catalysts illuminate the reactivity of isolated silanol sites

    SciTech Connect (OSTI)

    Mouat, Aidan R.; George, Cassandra; Kobayashi, Takeshi; Pruski, Marek; van?Duyne, Richard P.; Marks, Tobin J.; Stair, Peter C.

    2015-09-23

    The reaction of ?-alumina with tetraethylorthosilicate (TEOS) vapor at low temperatures selectively yields monomeric SiO<sub>x> species on the alumina surface. These isolated (-AlO)<sub>3sub>Si(OH) sites are characterized by PXRD, XPS, DRIFTS of adsorbed NH<sub>3sub>, CO, and pyridine, and 29Si and 27Al DNP-enhanced solid-state NMR spectroscopy. The formation of isolated sites suggests that TEOS reacts preferentially at strong Lewis acid sites on the ?-Al<sub>2sub>O>3sub> surface, functionalizing the surface with mild Brnsted acid sites. As a result, for liquid-phase catalytic cyclohexanol dehydration, these SiO<sub>x> sites exhibit up to 3.5-fold higher specific activity than the parent alumina with identical selectivity.

  10. Summary Report for the Development of Materials for Volatile Radionuclides

    SciTech Connect (OSTI)

    Strachan, Denis M.; Chun, Jaehun; Henager, Charles H.; Matyas, Josef; Riley, Brian J.; Ryan, Joseph V.; Thallapally, Praveen K.

    2010-11-22

    The materials development summarized here is in support of the Waste Forms campaign, Volatile Radionuclide task. Specifically, materials are being developed for the removal and immobilization of iodine and krypton, specifically 129I and 85Kr. During FY 2010, aerogel materials were investigated for removal and immobilization of 129I. Two aerogel formulations were investigated, one based on silica aerogels and the second on chalcogenides. For 85Kr, metal organic framework (MOF) structures were investigated.

  11. Structural phase transitions in Bi<sub>2sub>Se>3sub> under high pressure

    SciTech Connect (OSTI)

    Yu, Zhenhai; Gu, Genda; Wang, Lin; Hu, Qingyang; Zhao, Jinggeng; Yan, Shuai; Yang, Ke; Sinogeikin, Stanislav; Mao, Ho -kwang

    2015-11-02

    Raman spectroscopy and angle dispersive X-ray diffraction (XRD) experiments of bismuth selenide (Bi<sub>2sub>Se>3sub>) have been carried out to pressures of 35.6 and 81.2 GPa, respectively, to explore its pressure-induced phase transformation. The experiments indicate that a progressive structural evolution occurs from an ambient rhombohedra phase (Space group (SG): R-3m) to monoclinic phase (SG: C2/m) and eventually to a high pressure body-centered tetragonal phase (SG: I4/mmm). Evidenced by our XRD data up to 81.2 GPa, the Bi<sub>2sub>Se>3sub> crystallizes into body-centered tetragonal structures rather than the recently reported disordered body-centered cubic (BCC) phase. Furthermore, first principles theoretical calculations favor the viewpoint that the I4/mmm phase Bi<sub>2sub>Se>3sub> can be stabilized under high pressure (>30 GPa). Remarkably, the Raman spectra of Bi<sub>2sub>Se>3sub> from this work (two independent runs) are still Raman active up to ~35 GPa. Furthermore, it is worthy to note that the disordered BCC phase at 27.8 GPa is not observed here. The remarkable difference in atomic radii of Bi and Se in Bi<sub>2sub>Se>3sub> may explain why Bi<sub>2sub>Se>3sub> shows different structural behavior than isocompounds Bi<sub>2sub>Te>3sub> and Sb<sub>2sub>Te>3sub>.

  12. Effects of Mg doping on the remarkably enhanced electrochemical performance of Na<sub>3sub>V>2sub>(PO>4sub>)>3sub> cathode materials for sodium ion batteries

    SciTech Connect (OSTI)

    Li, Hui; Yu, Xiqian; Bai, Ying; Wu, Feng; Wu, Chuan; Liu, Liang-Yu; Yang, Xiao-Qing

    2015-01-01

    Na<sub>3sub>V>2-xsub>Mgx(PO>4sub>)>3sub>/C composites with different Mg2+ doping contents (x=0, 0.01, 0.03, 0.05, 0.07 and 0.1) were prepared by a facile sol-gel method. The doping effects on the crystal structure were investigated by XRD, XPS and EXAFS. The results show that low dose doping Mg2+ does not alter the structure of the material, and magnesium is successfully substituted for vanadium site. The Mg doped Na<sub>3sub>V>2-xsub>Mgx(PO>4sub>)>3sub>/C composites exhibit significant improvements on the electrochemistry performances in terms of the rate capability and cycle performance, especially for the Na<sub>3sub>V>1.95sub>Mg>0.05sub>(PO>4sub>)>3sub>/C. For example, when the current density increased from 1 C to 30 C, the specific capacity only decreased from 112.5 mAh g-1 to 94.2 mAh g-1 showing very good rate capability. Moreover, even cycling at a high rate of 20 C, an excellent capacity retention of 81% is maintained from the initial value of 106.4 mAh g-1 to 86.2 mAh g-1 at the 50th cycle. Enhanced rate capability and cycle performance can be attributed to the optimized particle size, structural stability and enhanced ionic and electronic conductivity induced by Mg doping.

  13. Cr-doped Ge{sub 2}Sb{sub 2}Te{sub 5} for ultra-long data retention phase change memory

    SciTech Connect (OSTI)

    Wang, Qing; Xia, Yangyang; Zheng, Yonghui; Zhang, Qi; Liu, Bo Song, Sannian; Cheng, Yan; Song, Zhitang; Feng, Songlin; Huo, Ruru

    2015-11-30

    Phase change memory is regarded as one of the most promising candidates for the next-generation non-volatile memory. Its storage medium, phase change material, has attracted continuous exploration. Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) is the most popular phase change material, but its thermal stability needs to be improved when used in some fields at high temperature (more than 120 °C). In this paper, we doped Cr atoms into GST and obtained Cr{sub 10}(Ge{sub 2}Sb{sub 2}Te{sub 5}){sub 90} (labeled as Cr-GST) with high thermal stability. For Cr-GST film, the sheet resistance ratio between amorphous and crystalline states is high up to 3 orders of magnitude. The crystalline Cr-GST film inherits the phase structure of GST, with metastable face-centered cubic phase and/or stable hexagonal phase. The doped Cr atoms not only bond with other atoms but also help to improve the anti-oxidation property of Cr-GST. As for the amorphous thermal stability, the calculated temperature for 10-year-data-retention of Cr-GST film, based on the Arrhenius equation, is about 180 °C. The threshold current and threshold voltage of a cell based on Cr-GST are about 6 μA and 2.7 V. The cell could be operated by suitable voltages for more than 40 000 cycles. Thus, Cr-GST is proved to be a promising phase change material with ultra-long data retention.

  14. Influence of Electron Doping on Magnetic Order in CeRu<sub>2sub>Al>10sub>

    SciTech Connect (OSTI)

    Kobayashi, Riki; Kaneko, Koji; Saito, Kotaro; Mignot, Jean-Michel; André, Gilles; Robert, Julien; Wakimoto, Shuichi; Matsuda, Masaaki; Chi, Songxue; Haga, Yoshinori; Matsuda, Tatsuma D.; Yamamoto, Etsuji; Nishioka, Takashi; Matsumura, Masahiro; Tanida, Hiroshi; Sera, Masafumi

    2014-09-17

    The effect of electron doping by the substitution of Rh for Ru on unconventional magnetic order in CeRu<sub>2sub>Al>10sub> was investigated via neutron powder diffraction. In Ce(Ru<sub>1-xsub>Rhx)>2sub>Al>10sub> with x = 0.05, 0.12, and 0.2, reorientation of the ordered moment from the c- to the a-axis takes place in all samples, while the ordering vector q=(0 1 0) remains unchanged within this concentration range. The moment reorientation is accompanied by an enhancement in its size by a factor of ~2.4, from μ=0.43 μ<sub>B> at x=0 to μ =1.06, 1.04, and 1.02 μ<sub>B> for x=0.05, 0.12 and 0.2, respectively. The continuous decrease in N´eel temperature T<sub>0sub>(TN>), despite an abrupt increase in μ , underlines the strong anisotropy in the exchange interaction in CeRu<sub>2sub>Al>10sub>, and the fact that this anisotropy is easily suppressed by electron doping.

  15. Octonary resistance states in La<sub>0.7sub>Sr>0.3sub>MnO>3sub>/BaTiO>3sub>/La>0.7sub>Sr>0.3sub>MnO>3sub> multiferroic tunnel junctions

    SciTech Connect (OSTI)

    Yue -Wei Yin; Tao, Jing; Huang, Wei -Chuan; Liu, Yu -Kuai; Yang, Sheng -Wei; Dong, Si -Ning; Zhu, Yi -Mei; Li, Qi; Li, Xiao -Guang

    2015-10-06

    General drawbacks of current electronic/spintronic devices are high power consumption and low density storage. A multiferroic tunnel junction (MFTJ), employing a ferroelectric barrier layer sandwiched between two ferromagnetic layers, presents four resistance states in a single device and therefore provides an alternative way to achieve high density memories. Here, an MFTJ device with eight nonvolatile resistance states by further integrating the design of noncollinear magnetization alignments between the ferromagnetic layers is demonstrated. Through the angle-resolved tunneling magnetoresistance investigations on La<sub>0.7sub>Sr>0.3sub>MnO>3sub>/BaTiO>3sub>/La>0.7sub>Sr>0.3sub>MnO>3sub> junctions, it is found that, besides collinear parallel/antiparallel magnetic configurations, the MFTJ shows at least two other stable noncollinear (45° and 90°) magnetic configurations. As a result, combining the tunneling electroresistance effect caused by the ferroelectricity reversal of the BaTiO<sub>3sub> barrier, an octonary memory device is obtained, representing potential applications in high density nonvolatile storage in the future.

  16. Evidence for tt?? Production and Measurement of (?<sub> tt?sub>)?/(?tt?>)

    SciTech Connect (OSTI)

    Aaltonen, T; Alvarez Gonzalez, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Apresyan, A; Arisawa, T

    2011-08-31

    Using data corresponding to 6.0 fb-1 of pp? collisions at ?s = 1.96 TeV collected by the CDF II detector, we present a cross section measurement of top-quark pair production with an additional radiated photon, tt??. The events are selected by looking for a lepton (ell), a photon (?), significant transverse momentum imbalance (E<sub>T>), large total transverse energy, and three or more jets, with at least one identified as containing a b quark (b). The tt?? sample requires the photon to have 10 GeV or more of transverse energy, and to be in the central region. Using an event selection optimized for the tt?? candidate sample we measure the production cross section of tt? (?<sub>tt?>), and the ratio of cross sections of the two samples. Control samples in the dilepton+photon and lepton+photon+E<sub>T>, channels are constructed to aid in decay product identification and background measurements. We observe 30 tt?? candidate events compared to the standard model expectation of 26.9 3.4 events. We measure the tt?? cross section (?<sub>tt?>) to be 0.18 0.08 pb, and the ratio of ?<sub>tt?>? to ?<sub>tt?> to be 0.024 0.009. Assuming no tt?? production, we observe a probability of 0.0015 of the background events alone producing 30 events or more, corresponding to 3.0 standard deviations.

  17. La??<sub>xSrx>CuO? superconductor nanowire devices

    SciTech Connect (OSTI)

    Litombe, N. E.; Bollinger, A. T.; Hoffman, J. E.; Bozovic, I.

    2014-07-02

    La??<sub>xSrx>CuO? nanowire devices have been fabricated and characterized using electrical transport measurements. Nanowires with widths down to 80 nm are patterned using high-resolution electron beam lithography. However, the narrowest nanowires show incomplete superconducting transitions with some residual resistance at T = 4 K. Here, we report on refinement of the fabrication process to achieve narrower nanowire devices with complete superconducting transitions, opening the path to the study of novel physics arising from dimension-limited superconductivity on the nanoscale.

  18. Influence of Ga-concentration on the electrical and magnetic properties of magnetoelectric CoGa<sub>xFe>2–xsub>O>4sub>/BaTiO>3sub> composite

    SciTech Connect (OSTI)

    Ni, Yan; Zhang, Zhen; Nlebedim, Cajetan I.; Jiles, David C.

    2015-03-20

    Multiferroic materials exhibit magnetoelectric (ME) coupling and promise new device applications including magnetic sensors, generators, and filters. An effective method for developing ME materials with enhanced ME effect is achieved by the coupling through the interfacial strain between piezoelectric and magnetostrictive materials. In this study, the electrical and magnetic properties of Ga doped magnetoelectric CoGa<sub>xFe>2–xsub>O>4sub>/BaTiO>3sub> composite are studied systematically. It is found that Ga doping improves the sensitivity of magnetoelastic response and stabilizes the magnetic phase of the composites. More importantly, Ga doping reduces the electrical conductivity of composite, as well as the dielectric loss. An enhancement of the electrostrain with doping Ga is also observed. Quantitative estimation indicates that magnetoelectric coupling is enhanced for Ga-doped CoGa<sub>xFe>2–xsub>O>4sub>/BaTiO>3sub> composites. As a result, the present work is beneficial to the practical application of composite CoFe<sub>2sub>O>4sub>/BaTiO>3sub>-based multiferroic materials.

  19. Scaling of Dynamic Spin Correlations in BaCu<sub>2sub>(Si>0.5sub>Ge>0.5sub>)>2sub>O>7sub>

    SciTech Connect (OSTI)

    Zheludev, Andrey I; Masuda, T.; Dhalenne, G.; Revcolevschi, A.; Frost, C.; Perring, T. G.

    2007-01-01

    The magnetic dynamic structure factor of the one-dimensional S=1/2 chain system BaCu{sub 2}(Si{sub 0.5}Ge{sub 0.5}){sub 2}O{sub 7} is studied in a wide range of energy transfers and temperatures. Contrary to previous erroneous reports [T. Masuda et al., Phys. Rev. Lett. 93, 077206 (2004)], the scaling properties observed in the range 0.5-25 meV are found to be fully consistent with expectations for a Luttinger spin liquid. At higher energies, a breakdown of scaling laws is observed and attributed to lattice effects. The results are complementary to those found in literature for other S=1/2 chain compounds, such as KCuF{sub 3} and Cu benzoate.

  20. Processing optimization and sintering time dependent magnetic and optical behaviors of Aurivillius Bi{sub 5}Ti{sub 3}FeO{sub 15} ceramics

    SciTech Connect (OSTI)

    Chen Guang; Sun Lin; Ren Qing; Xu Wenfei; Yang Jing; Tang Xiaodong; Bai Wei; Duan Chungang; Chu Junhao; Wu Jing; Meng Xiangjian

    2013-01-21

    Aurivillius Bi{sub 5}Ti{sub 3}FeO{sub 15} (BTF) ceramics were synthesized using the conventional solid state reaction method by optimizing excess of Bi{sub 2}O{sub 3} and sintering time. Their structures, magnetic, and optical properties were investigated in detail. The optimum process to sinter pure Aurivillius BTF ceramics was confirmed to be 3 wt. % excess Bi{sub 2}O{sub 3} to compensate the Bi volatilization at 1050 Degree-Sign C for 240 min (BTF-240M). The microstructure and crystalline structure of the BTF ceramics had little dependence on the sintering time from the x-ray diffraction (XRD) and scanning electron microscopic data. Nevertheless, the magnetic and optical properties were closely related with the sintering time. The overall magnetic behavior of these BTF ceramics was superparamagnetic (SPM), whereas there were unambiguous clues for the existence of antiferromagnetic (AFM) interactions. However, whether the SPM behavior was intrinsic or arised from a tiny amount of spinel Fe{sub 3}O{sub 4} impurity phase cannot be thoroughly ruled out in the XRD detection limit in the present stage. The AFM interactions were weakened upon extending the sintering time. The effective magnetic moment ({mu}{sub eff}), however, demonstrated different dependency on the sintering time. It increased with the sintering time from 80 min to 240 min, and then dropped with further extending the sintering time. Compared with other BTF ceramics, the BTF-240M ceramic showed the highest values of the refractive index n and real part {epsilon}{sub 1}, as well as the lowest ones of the extinction coefficient k and imagine part {epsilon}{sub 2} in whole photon energy range. Finally, a direct inter-band transition was confirmed for these BTF ceramics and optical energy band gaps were determined to be about 3.08, 3.18, and 3.39 eV for 80 min, 150 min, and 240 min sintered BTF ceramics, respectively, yet abnormal optical behavior was observed in BTF-360M ceramic.

  1. Eu<sub>3sub>Ir>2sub>In>15sub>: A mixed-valent and vacancy-filled variant of the Sc<sub>5sub>Co>4sub>Si>10sub> structure type with anomalous magnetic properties

    SciTech Connect (OSTI)

    Sarkar, Sumanta; Jana, Rajkumar; Siva, Ramesh; Banerjee, Swastika; Pati, Swapan K.; Balasubramanian, Mahalingam; Peter, Sebastian C.

    2015-10-27

    Here, a new compound, Eu<sub>3sub>Ir>2sub>In>15sub> has been synthesized using indium as an active metal flux. The compound crystallizes in tetragonal P4/mbm space group with lattice parameters, a = 14.8580(4) Å, b = 14.8580(4) Å, c = 4.3901(2) Å. It was further characterized by SEM-EDX studies. The temperature dependent magnetic susceptibility suggests that Eu in this compound is exclusively in divalent state. The effective magnetic moment (μ<sub>eff>) of this compound is 7.35 μ<sub>B>/Eu ion with paramagnetic Curie temperature (θ<sub>p>) of -28 K suggesting antiferromagnetic interaction. The mixed valent nature of Eu observed in magnetic measurements was confirmed by XANES measurements. The compound undergoes demagnetization at a low magnetic field (10 Oe), which is quite unusual for Eu based intermetallic compounds. Temperature dependent resistivity studies reveal that the compound is metallic in nature. A comparative study was made between Eu<sub>3sub>Ir>2sub>In>15sub> and hypothetical vacancy variant Eu<sub>5sub>Ir>4sub>In>10sub> which also crystallizes in the same crystal structure However our computational studies along with control experiments suggest that the latter is thermodynamically less feasible compared to the former and hence we proposed that it is highly unlikely that a RE<sub>5sub>T>4sub>X>10sub> would exist with X as a group 13 elements.

  2. The thermal conductivity of mixed fuel U<sub>xPu>1-xsub>O>2sub>: molecular dynamics simulations

    SciTech Connect (OSTI)

    Liu, Xiang-Yang; Cooper, Michael William Donald; Stanek, Christopher Richard; Andersson, Anders David Ragnar

    2015-10-16

    Mixed oxides (MOX), in the context of nuclear fuels, are a mixture of the oxides of heavy actinide elements such as uranium, plutonium and thorium. The interest in the UO<sub>2sub>-PuO>2sub> system arises from the fact that these oxides are used both in fast breeder reactors (FBRs) as well as in pressurized water reactors (PWRs). The thermal conductivity of UO<sub>2sub> fuel is an important material property that affects fuel performance since it is the key parameter determining the temperature distribution in the fuel, thus governing, e.g., dimensional changes due to thermal expansion, fission gas release rates, etc. For this reason it is important to understand the thermal conductivity of MOX fuel and how it differs from UO<sub>2sub>. Here, molecular dynamics (MD) simulations are carried out to determine quantitatively, the effect of mixing on the thermal conductivity of U<sub>xPu>1-xsub>O>2sub>, as a function of PuO<sub>2sub> concentrations, for a range of temperatures, 300 – 1500 K. The results will be used to develop enhanced continuum thermal conductivity models for MARMOT and BISON by INL. These models express the thermal conductivity as a function of microstructure state-variables, thus enabling thermal conductivity models with closer connection to the physical state of the fuel.

  3. Annealing influence on the magnetostructural transition in Gd<sub>5sub>Si>1.3sub>Ge>2.7sub> thin films

    SciTech Connect (OSTI)

    Pires, A. L.; Belo, J. H.; Gomes, I. T.; Hadimani, R. L.; Jiles, D. C.; Fernandes, L.; Tavares, P. B.; Araújo, J. P.; Lopes, A. M. L.; Pereira, A. M.

    2015-05-19

    Due to the emerging cooling possibilities at the micro and nanoscale, such as the fast heat exchange rate, the effort to synthesize and optimize the magnetocaloric materials at these scales is rapidly growing. Here, we report the effect of different thermal treatments on Gd<sub>5sub>Si>1.3sub>Ge>2.7sub> thin film in order to evaluate the correlation between the crystal structure, magnetic phase transition and magnetocaloric effect. For annealing temperatures higher than 500ºC, the samples showed a typical paramagnetic behavior. On the other hand, thermal treatments below 500ºC promoted the suppression of the magnetostructural transition at 190 K, while the magnetic transition around 249 K is not affected. This magnetostructural transition extinction was reflected in the magnetocaloric behavior and resulted in a drastic decrease in the entropy change peak value (of about 68%). An increase in T<sub>C> was reported, proving that at the nanoscale, heat treatments may be a useful tool to optimize the magnetocaloric properties in Gd<sub>5sub>(SixGe>1-xsub>)>4sub> thin films.

  4. Synthesis and thermoelectric properties of RuO{sub 2} nanorods

    SciTech Connect (OSTI)

    Music, Denis; Basse, Felix H.-U.; Schneider, Jochen M.; Hassdorf, Ralf

    2010-07-15

    We have explored the effect of the O/Ru ratio on the morphology and the Seebeck coefficient of RuO{sub 2} nanorods (space group P4{sub 2}/mnm) synthesized by reactive sputtering. At an O/Ru ratio of 1.69, a faceted surface is observed, while nanorod formation occurs at O/Ru ratios of 2.03 and 2.24. Using classical molecular dynamics with the potential parameters derived in this work, we show that volatile species enable nanorod formation. Based on ab initio calculations, two effects of the nanorod formation on the Seebeck coefficient are observed: (i) increase due to additional states in the vicinity of the Fermi level and (ii) decrease due to oxygen point defects (volatile species). These two competing effects give rise to a moderate increase in the Seebeck coefficient upon nanorod formation.

  5. Specific heat investigation for line nodes in heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub>

    SciTech Connect (OSTI)

    Kim, J. S.; Stewart, G. R.; Liu, Yong; Lograsso, Thomas A.

    2015-06-10

    Previous research has found that the pairing symmetry in the iron-based superconductor Ba<sub>1-xsub>KxFe>2sub>As>2sub> changes from nodeless s-wave near optimally doped, x?0.4-0.55 and T<sub>c>>30 K, to nodal (either d-wave or s-wave) at the pure endpoint, x=1 and T<sub>c><4 K. Intense theoretical interest has been focused on this possibility of changing pairing symmetry, where in the transition region both order parameters would be present and time reversal symmetry would be broken. Here we report specific heat measurements in zero and applied magnetic fields down to 0.4 K of three individual single crystals, free of low temperature magnetic anomalies, of heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub>, x= 0.91, 0.88, and 0.81. The values for T<sub>c>mid are 5.6, 7.2 and 13 K and for H<sub>c2sub>? 4.5, 6, and 20 T respectively. Furthermore, the data can be analyzed in a two gap scenario, ?<sub>2sub>/?>1sub> ? 4, with the magnetic field dependence of ? (=C/T as T?0) showing an anisotropic S-shaped behavior vs H, with the suppression of the lower gap by 1 T and ? ? H1/2 overall. Although such a non-linear ? vs H is consistent with deep minima or nodes in the gap structure, it is not clear evidence for one, or both, of the gaps being nodal in these overdoped samples. Thus, following the established theoretical analysis of the specific heat of d-wave cuprate superconductors containing line nodes, we present the specific heat normalized by H1/2 plotted vs T/H1/2 of these heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub> samples which thanks to the absence of magnetic impurities in our sample - convincingly shows the expected scaling for line node behavior for the larger gap for all three compositions. There is however no clear observation of the nodal behavior C ? ?T2 in zero field at low temperatures, with ? ? 2 mJ/molK3 being consistent with the data. Together with the scaling, this leaves open the possibility of extreme anisotropy in a nodeless larger gap, ?<sub>2sub>, such that the scaling works for fields above 0.25 0.5 T (0.2 0.4 K in temperature units), where this an estimate for the size of the deep minima in the ?<sub>2sub> ~ 20-25 K gap. Furthermore, the location of the change from nodeless?nodal gaps between optimally doped and heavily overdoped Ba<sub>1-xsub>KxFe>2sub>As>2sub> based on the present work may be closer to the KFe<sub>2sub>As>2sub> endpoint than x=0.91.

  6. Magnetic structure of the antiferromagnetic Kondo lattice compounds CeRhAl<sub>4sub>Si>2sub> and CeIrAl<sub>4sub>Si>2sub>

    SciTech Connect (OSTI)

    Ghimire, N. J.; Calder, S.; Janoschek, M.; Bauer, E. D.

    2015-06-01

    In this article, we have investigated the magnetic ground state of the antiferromagnetic Kondo-lattice compounds CeMAl<sub>4sub>Si>2sub>(M = Rh, Ir) using neutron powder diffraction. Although both of these compounds show two magnetic transitions T<sub>N1sub> and T<sub>N2sub> in the bulk properties measurements, evidence for magnetic long-range order was only found below the lower transition T<sub>N2sub>. Analysis of the diffraction profiles reveals a commensurate antiferromagnetic structure with a propagation vector k = (0, 0, 1/2). The magnetic moment in the ordered state of CeRhAl<sub>4sub>Si>2sub> and CeIrAl<sub>4sub>Si>2sub> were determined to be 1.14(2) and 1.41(3) <sub>?B>/Ce, respectively, and are parallel to the crystallographic c-axis in agreement with magnetic susceptibility measurements.

  7. Synthesis, structure, and physical properties of [Sm(C{sub 6}NO{sub 2}H{sub 5}){sub 3}(H{sub 2}O){sub 2}]{sub 2n}.(H{sub 5}O{sub 2}){sub n}(ZnCl{sub 5}){sub n}(ZnCl{sub 4}){sub 2n}.(H{sub 2}O){sub 2n} with unprecedented ZnCl{sub 5}{sup 3-} species

    SciTech Connect (OSTI)

    Xie Yiming Chen Wentong; Wu Jihuai

    2008-08-15

    A novel bimetallic 4f-3d metal-isonicotinic acid inorganic-organic hybrid complex [Sm(C{sub 6}NO{sub 2}H{sub 5}){sub 3}(H{sub 2}O){sub 2}]{sub 2n}.(H{sub 5}O{sub 2}){sub n}(ZnCl{sub 5}){sub n}(ZnCl{sub 4}){sub 2n}.(H{sub 2}O){sub 2n} (1) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 is characteristic of a one-dimensional polycationic chain-like structure and unprecedented ZnCl{sub 5}{sup 3-} species. Photoluminescent investigation reveals that the title complex displays interesting emissions in a wide region. Optical absorption spectra of 1 reveal the presence of an optical gap of 3.59 eV. - Graphical abstract: A novel bimetallic 4f-3d metal-isonicotinic acid inorganic-organic hybrid complex was synthesized. It is characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation reveals that the title complex displays interesting emissions in a wide region. Optical absorption spectra of 1 reveal the presence of a wide optical bandgap.

  8. Fiber optic spectrochemical emission sensor: Detection of volatile chlorinated compounds in air and water using ultra-thin membranes

    SciTech Connect (OSTI)

    Anheier, N.C. Jr.; Olsen, K.B.; Osantowski, R.E.; Evans, J.C. Jr.; Griffin, J.W.

    1993-05-01

    Prior work on the fiber optic spectrochemical emission sensor called HaloSnif{trademark} has been extended to include an ultra-thin membrane which allows passage of volatile organic chlorinated compounds (VOCl). The membrane has been demonstrated to exclude H{sub 2}O during VOCl monitoring. The system is capable of measuring VOCl in gas-phase samples or aqueous solutions over a wide linear dynamic range. The lower limit of detection for trichloroethylene (TCE), perchloroethylene (PCE), carbon tetrachloride (CCl{sub 4}), and other related compounds in the gas-phase is 1 to 5 ppm{sub v/v}, and in the aqueous-phase is 5 to 10 mg/L. Waste site characterization and remediation activities often require chemical analysis in the vadose zone and in groundwater. These analyses are typically performed in analytical laboratories using widely accepted standardized methods such as gas chromatography, gas chromatography/mass spectrometry. The new developments with HaloSnif provide rapid field screening which can augment the standardized methods.

  9. The CO<sub>2sub> permeability and mixed gas CO<sub>2sub>/H>2sub> selectivity of membranes composed of CO<sub>2sub>-philic polymers

    SciTech Connect (OSTI)

    Barillas, Mary Katharine; Enick, Robert M.; O’Brien, Michael; Perry, Robert; Luebke, David R.; Morreale, Bryan D.

    2011-04-01

    The objective of this work was to design polymeric membranes that have very high CO<sub>2sub> permeability and high mixed gas selectivity toward CO<sub>2sub> rather than hydrogen. Therefore the membranes were based on "CO<sub>2sub>-philic" polymers that exhibit thermodynamically favorable Lewis acid:Lewis base and hydrogen bonding interactions with CO<sub>2sub>. CO<sub>2sub>-philic polymers that are solid at ambient temperature include polyfluoroacrylate (PFA); polyvinyl acetate (PVAc); and amorphous polylactic acid (PLA). Literature CO<sub>2sub> permeability values for PVAc and PLA are disappointingly low. The cast PFA membranes from this study had low permeabilities (45 barrers at 25º C) and very low CO<sub>2sub>/H>2sub> selectivity of 1.4. CO<sub>2sub>-philic polymers that are liquid at ambient conditions include polyethylene glycol (PEG), polypropylene glycol (PPG), polybutylene glycol with a linear -((CH<sub>2sub>)>4sub>O)-repeat unit (i.e., polytetramethylene ether glycol (PTMEG)), polybutylene glycol (PBG) with a branched repeat unit, perfluoropolyether (PFPE), poly(dimethyl siloxane) (PDMS), and polyacetoxy oxetane (PAO). A small compound, glycerol triacetate (GTA) was also considered because it is similar in chemical structure to a trimer of PVAc. These liquids were tested as supported liquid membranes (SLM) and also (with the exception of PAD and GTA) as rubbery, crosslinked materials. Mixed gas permeability was measured using equimolar mixtures of CO<sub>2sub> and H<sub>2sub> feed streams at one atmosphere total pressure in steady-state flux experiments over the 298-423 K temperature range. The most promising SLMs were those composed of PEG, PTMEG, GTA, and PDMS. For example, at 37º C the PEG-, PTMEG-, GTA- and PDMS-based SLMs exhibited CO<sub>2sub>/H>2sub> selectivity values of ~11, 9, 9, and 3.5, respectively, and CO<sub>2sub> permeability values of ~800, 900, 1900, and 2000 barrers, respectively. Crosslinked versions of the PEG, PTMEG and PDMS membranes at 37º C exhibited selectivity values of ~5, 6, and 3.5, respectively, and CO<sub>2sub> permeability values of ~50, 300, and 3000 barrers, respectively.

  10. Magnetic hardening of Ce<sub>1+xsub>Fe>11ysub>Coy>Ti with ThMn<sub>12sub> structure by melt spinning

    SciTech Connect (OSTI)

    Zhou, Chen; Sun, Kewei; Pinkerton, Frederick E.; Kramer, M. J.

    2015-04-15

    A recent study on the intrinsic magnetic properties of CeFe<sub>11ysub>Coy>Ti has revealed that substituting one Co for Fe retains the favorable magnetocrystalline anisotropy H<sub>a> found in the ternary Fe end member, while enhancing the Curie temperature T<sub>c> and saturation magnetization 4?M<sub>s>. These findings warrant further optimization around Co substitution y = 1 to try to exploit the hard magnetic properties of these Ce-based magnets. Both Ce and Co concentrations in Ce<sub>1+xsub>Fe>11ysub>Coy>Ti have been optimized in the range of x = 0 0.2 and y = 0 1.5. It was found that Co substitution effectively enhances all hard magnetic properties, although the values are still lower than those predicted from the intrinsic magnetic properties. Specifically, T<sub>c> increases from 210 C to 285 350 C; 4?M<sub>19sub> (magnetization at 19 kOe) from 8.9 kG to 10.5 11.5 kG, remanence Br from 3.1 kG to 4.1 4.5 kG, and most importantly, H<sub>ci> from 1.1 kOe to 1.5 kOe. As a result, the room temperature energy product (BH)<sub>max> has been increased by over 100% from 0.7 MGOe in Ce<sub>1.1sub>Fe>11sub>Ti to 1.5 MGOe in Ce<sub>1.05sub>Fe>9.75sub>Co>1.25sub>Ti. Microscopy analysis indicates that the addition of Co refines the grain size and promotes chemical homogeneity at the microscopic scale. As a result, the beneficial effect of Co on the microstructure contributes to the improved hard magnetic properties.

  11. Efficient growth of HTS films with volatile elements

    DOE Patents [OSTI]

    Siegal, Michael P.; Overmyer, Donald L.; Dominguez, Frank

    1998-01-01

    A system for applying a volatile element-HTS layer, such as Tl-HTS, to a substrate in a multiple zone furnace, said method includes heating at higher temperature, in one zone of the furnace, a substrate and adjacent first source of Tl-HTS material, to sublimate Tl-oxide from the source to the substrate; and heating at lower temperature, in a separate zone of the furnace, a second source of Tl-oxide to replenish the first source of Tl-oxide from the second source.

  12. Efficient growth of HTS films with volatile elements

    DOE Patents [OSTI]

    Siegal, M.P.; Overmyer, D.L.; Dominguez, F.

    1998-12-22

    A system is disclosed for applying a volatile element-HTS layer, such as Tl-HTS, to a substrate in a multiple zone furnace, said method includes heating at higher temperature, in one zone of the furnace, a substrate and adjacent first source of Tl-HTS material, to sublimate Tl-oxide from the source to the substrate; and heating at lower temperature, in a separate zone of the furnace, a second source of Tl-oxide to replenish the first source of Tl-oxide from the second source. 3 figs.

  13. Reactive Flash Volatilization of Solid, Nonvolatile Fuel - Energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Innovation Portal Biomass and Biofuels Biomass and Biofuels Find More Like This Return to Search Reactive Flash Volatilization of Solid, Nonvolatile Fuel DOE Grant Recipients University of Minnesota Contact University of Minnesota About This Technology <span id="Caption"><span id="ctl00_MainContentHolder_zoomimage_defaultCaption">Syngas or Synthesis Gas</span></span> Syngas or Synthesis Gas <span id="Caption"><span

  14. Modeling CO{sub 2}-Brine-Rock Interaction Including Mercury and H{sub 2}S Impurities in the Context of CO{sub 2} Geologic Storage

    SciTech Connect (OSTI)

    Spycher, N.; Oldenburg, C.M.

    2014-01-01

    This study uses modeling and simulation approaches to investigate the impacts on injectivity of trace amounts of mercury (Hg) in a carbon dioxide (CO{sub 2}) stream injected for geologic carbon sequestration in a sandstone reservoir at ~2.5 km depth. At the range of Hg concentrations expected (7-190 ppbV, or ~ 0.06-1.6 mg/std.m{sup 3}CO{sub 2}), the total volumetric plugging that could occur due to complete condensation of Hg, or due to complete precipitation of Hg as cinnabar, results in a very small porosity change. In addition, Hg concentration much higher than the concentrations considered here would be required for Hg condensation to even occur. Concentration of aqueous Hg by water evaporation into CO{sub 2} is also unlikely because the higher volatility of Hg relative to H{sub 2}O at reservoir conditions prevents the Hg concentration from increasing in groundwater as dry CO{sub 2} sweeps through, volatilizing both H{sub 2}O and Hg. Using a model-derived aqueous solution to represent the formation water, batch reactive geochemical modeling show that the reaction of the formation water with the CO{sub 2}-Hg mixture causes the pH to drop to about 4.7 and then become buffered near 5.2 upon reaction with the sediments, with a negligible net volume change from mineral dissolution and precipitation. Cinnabar (HgS(s)) is found to be thermodynamically stable as soon as the Hg-bearing CO{sub 2} reacts with the formation water which contains small amounts of dissolved sulfide. Liquid mercury (Hg(l)) is not found to be thermodynamically stable at any point during the simulation. Two-dimensional radial reactive transport simulations of CO{sub 2} injection at a rate of 14.8 kg/s into a 400 m-thick formation at isothermal conditions of 106°C and average pressure near 215 bar, with varying amounts of Hg and H{sub 2}S trace gases, show generally that porosity changes only by about ±0.05% (absolute, i.e., new porosity = initial porosity ±0.0005) with Hg predicted to readily precipitate from the CO{sub 2} as cinnabar in a zone mostly matching the single-phase CO{sub 2} plume. The precipitation of minerals other than cinnabar, however, dominates the evolution of porosity. Main reactions include the replacement of primarily Fe-chlorite by siderite, of calcite by dolomite, and of K-feldspar by muscovite. Chalcedony is also predicted to precipitate from the dissolution of feldspars and quartz. Although the range of predicted porosity change is quite small, the amount of dissolution and precipitation predicted for these individual minerals is not negligible. These reactive transport simulations assume that Hg gas behaves ideally. To examine effects of non-ideality on these simulations, approximate calculations of the fugacity coefficient of Hg in CO{sub 2} were made. Results suggest that Hg condensation could be significantly overestimated when assuming ideal gas behavior, making our simulation results conservative with respect to impacts on injectivity. The effect of pressure on Henry’s constant for Hg is estimated to yield Hg solubilities about 10% lower than when this effect is not considered, a change that is considered too small to affect the conclusions of this report. Although all results in this study are based on relatively mature data and modeling approaches, in the absence of experimental data and more detailed site-specific information, it is not possible to fully validate the results and conclusions.

  15. Structure determination of {alpha}-La{sub 6}W{sub 2}O{sub 15}

    SciTech Connect (OSTI)

    Chambrier, M-H.; Ibberson, R.M.; Goutenoire, F.

    2010-06-15

    The structure of the high temperature alpha form of La{sub 6}W{sub 2}O{sub 15} has been determined ab-initio from high temperature laboratory X-ray and neutron time-of-flight data. This tungstate crystallizes in the non-centrosymmetric orthorhombic space group (No. 20) C222{sub 1}, with Z=2, a=12.6250(2) A, b=9.1875(1) A, c=5.9688(1) A. The structure comprises [O{sub 2}La{sub 3}] infinite ribbons and is better described by the structural formula [O{sub 2}La{sub 3}]{sub 2}[WO{sub 5.5}]{sub 2}. Using this description we can understand the strong structural similarity of the present compound with compounds of the general composition BiM{sub 2}AO{sub 6} (M=Cu, Mg, Zn, Mn, Cd, Ca, Pb; A=P, As, V) described as [O{sub 2}M{sub 2}Bi][AO{sub 4}]. The [WO{sub 5.5}] entity implies oxygen disorder in the material. - Graphical abstract: Projection of the polyhedra around the tungsten atom. Atoms labelled in grey are occupied at 50%. Short oxygen-oxygen distances are marked. The polyhedra represents WO{sub 5.5} that is related to the structural unit W{sub 2}O{sub 11} unit. Alpha-La{sub 6}W{sub 2}O{sub 15} could be described as [O{sub 2}La{sub 3}]{sub 2}[WO{sub 5.5}]{sub 2}.

  16. Ferromagnetic superexchange in insulating Cr<sub>2sub>MoO>6sub> by controlling orbital hybridization

    SciTech Connect (OSTI)

    Zhu, M.; Do, D.; Dela Cruz, Clarina R.; Dun, Zhiling; Cheng, J. -G.; Goto, H.; Uwatoko, Yoshiya; Zou, T.; Zhou, Haidon D.; Mahanti, Subhendra D.; Ke, Xianglin

    2015-09-11

    We report the magnetic and electronic structures of the newly synthesized inverse-trirutile compound Cr<sub>2sub>MoO>6sub>. Despite the same crystal symmetry and similar bond-lengths and bond-angles to Cr<sub>2sub>TeO>6sub>, Cr<sub>2sub>MoO>6sub> possesses a magnetic structure of the Cr<sub>2sub>MoO>6sub> type, different from that seen in Cr<sub>2sub>TeO>6sub>. Ab-initio electronic structure calculations show that the sign and strength of the Cr-O-Cr exchange coupling is strongly influenced by the hybridization between Mo 4d and O 2p orbitals. This result further substantiates our recently proposed mechanism for tuning the exchange interaction between two magnetic atoms by modifying the electronic states of the non-magnetic atoms in the exchange path through orbital hybridization. This approach is fundamentally different from the conventional methods of controlling the exchange interaction by either carrier injection or through structural distortions.

  17. Ecosystem-scale volatile organic compound fluxes during an extreme drought

    Office of Scientific and Technical Information (OSTI)

    in a broadleaf temperate forest of the Missouri Ozarks (central USA) (Journal Article) | SciTech Connect Ecosystem-scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA) Citation Details In-Document Search Title: Ecosystem-scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA) Considerable amounts and varieties of biogenic volatile

  18. The effect of planets beyond the ice line on the accretion of volatiles by habitable-zone rocky planets

    SciTech Connect (OSTI)

    Quintana, Elisa V. [SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States); Lissauer, Jack J., E-mail: elisa.quintana@nasa.gov [Space Science and Astrobiology Division 245-3, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2014-05-01

    Models of planet formation have shown that giant planets have a large impact on the number, masses, and orbits of terrestrial planets that form. In addition, they play an important role in delivering volatiles from material that formed exterior to the snow line (the region in the disk beyond which water ice can condense) to the inner region of the disk where terrestrial planets can maintain liquid water on their surfaces. We present simulations of the late stages of terrestrial planet formation from a disk of protoplanets around a solar-type star and we include a massive planet (from 1 M {sub ?} to 1 M {sub J}) in Jupiter's orbit at ?5.2 AU in all but one set of simulations. Two initial disk models are examined with the same mass distribution and total initial water content, but with different distributions of water content. We compare the accretion rates and final water mass fraction of the planets that form. Remarkably, all of the planets that formed in our simulations without giant planets were water-rich, showing that giant planet companions are not required to deliver volatiles to terrestrial planets in the habitable zone. In contrast, an outer planet at least several times the mass of Earth may be needed to clear distant regions of debris truncating the epoch of frequent large impacts. Observations of exoplanets from radial velocity surveys suggest that outer Jupiter-like planets may be scarce, therefore, the results presented here suggest that there may be more habitable planets residing in our galaxy than previously thought.

  19. Magnetic field, frequency and temperature dependence of complex conductance of ultrathin La<sub>1.65sub>Sr>0.45sub>CuO>4sub>/La>2sub>CuO>4sub> films and the organic superconductors κ-(BEDT-TTF)<sub>2sub>Cu[N(CN)>2sub>]Br

    SciTech Connect (OSTI)

    V. A. Gasparov; Bozovic, I.; He, Xi; Dubuis, G.; Pavuna, D.; Kushch, N. D.; Yagubskii, E. B.; Schlueter, J. A.

    2015-09-01

    In this study, we used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La<sub>1.65sub>Sr>0.45sub>CuO>4sub>) and a cuprate insulator (La<sub>2sub>CuO>4sub>), in which interface superconductivity occurs in a layer that is just one-half unit cell thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films, and compared them to κκ-(BEDT-TTF)<sub>2sub>Cu[N(CN)>2sub>]Br single crystals. The magnetic field H was applied both parallel and perpendicular to the 2D conducting layers. Experiments have been carried out at frequencies between 23 kHz and 50 MHz using either two-coil mutual inductance technique, or the LC resonators with spiral or rectangular coils. The real and the imaginary parts of the mutual-inductance M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For H perpendicular to the conducting layers, we observed almost identical behavior in both films and κ-Br single crystals: (i) the transition onset in the inductive response, L<sub>k>–1(T) occurs at a temperature lower by 2 K than in Re σ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T) is exponential due to pinning of vortex cores. These results can be described by the extended dynamic theory of the Berezinski–Kosterlitz–Thouless (BKT) transition and dynamics of bound vortex–antivortex pairs with short separation lengths.

  20. Synthesis and Luminescence Characteristics of Cr3+ doped Y<sub>3sub>Al>5sub>O>12sub> Phosphors

    SciTech Connect (OSTI)

    Smith, Brenda A.; Dabestani, Reza T.; Lewis, Linda A.; Thompson, Cyril V.; Collins, Case T.; Aytug, Tolga

    2015-10-01

    Luminescence performance of yttrium aluminum garnet (Y<sub>3sub>Al>5sub>O>12sub>) phosphors as a function of Cr3+ concentration has been investigated via two different wet-chemical synthesis techniques, direct- (DP) and hydrothermal-precipitation (HP). Using either of these methods, the red-emitting phosphor [Y<sub>3sub>Al>5-xsub>CrxO>12sub> (YAG: Cr3+)] showed similar photoluminescence (PL) intensities once the dopant concentration was optimized. Specifically, the YAG: Cr3+ PL emission intensity reached a maximum at Cr3+ concentrations of x = 0.02 (0.4 at.%) and x = 0.13 (2.6 at.%) for DP and HP processed samples, respectively. The results indicated the strong influence of the processing method on the optimized YAG: Cr3+ performance, where a more effective energy transfer rate between a pair of Cr3+ activators at low concentration levels was observed by using the DP synthesis technique. Development of a highly efficient phosphor, using a facile synthesis approach, could significantly benefit consumer and industrial applications by improving the operational efficiency of a wide range of practical devices.

  1. Average and local crystal structures of (Ga<sub>1–xsub>Znx)(N>1–xsub>Ox>) solid solution nanoparticles

    SciTech Connect (OSTI)

    Feygenson, Mikhail; Neuefeind, Joerg C.; Tyson, Trevor A.; Schieber, Natalie; Han, Wei -Qiang

    2015-11-06

    We report the comprehensive study of the crystal structure of (Ga<sub>1–xsub>Znx)(N>1–xsub>Ox>) solid solution nanoparticles by means of neutron and synchrotron x-ray scattering. In our study we used four different types of (Ga<sub>1–xsub>Znx)(N>1–xsub>Ox>) nanoparticles, with diameters of 10–27 nm and x = 0.075–0.51, which show the narrow energy-band gaps from 2.21 to 2.61 eV. The Rietveld analysis of the neutron diffraction data revealed that the average crystal structure is the hexagonal wurtzite (space group P6<sub>3sub>mc), in agreement with previous reports on similar bulk materials. The pair-distribution function (PDF) analysis of the same data found that the local structure is more disordered than the average one. It is best described by the model with a lower symmetry space group P1, where atoms are quasirandomly distorted from their nominal positions in the hexagonal wurtzite lattice.

  2. Giant Magneto-Resistance in Epitaxial (La<sub>0.7sub>Sr>0.3sub>MnO>3sub>)>0.5sub>: (ZnO)<sub>0.5sub> Nanocomposites

    SciTech Connect (OSTI)

    Pan, Wei; Jiang, Y. X.; Ihlefeld, Jon; Lu, Ping; Lee, Stephen R.

    2015-12-01

    A great deal of research has been carried out in oxide material systems. Among them, ZnO and La<sub>0.7sub>Sr>0.3sub>MnO>3sub> (LSMO) are of particular interest due to their superb optical properties and colossal magneto-resistive effect. Here, we report our recent results of magneto-transport studies in self-assembled, epitaxial (ZnO)0.5:(La<sub>0.7sub>Sr>0.3sub>MnO>3sub>)>0.5sub> nanocomposite films.

  3. Volatility and entrainment of feed components and product glass characteristics during pilot-scale vitrification of simulated Hanford Site low-level waste

    SciTech Connect (OSTI)

    Whyatt, G.A. [Pacific Northwest National Lab., Richland, WA (United States); Shade, J.W.; Stegen, G.E. [Westinghouse Hanford Co., Richland, WA (United States)

    1996-12-31

    Commercially available melter technologies were tested for application to vitrification of Hanford Site low-level waste (LLW). Testing was conducted at vendor facilities using a non-radioactive LLW stimulant. Technologies tested included four Joule-heated melter types, a carbon electrode melter, a cyclone combustion melter, and a plasma torch-fired melter. A variety of samples were collected during the vendor tests and analyzed to provide data to support evaluation of the technologies. This paper describes the evaluation of melter feed component volatility and entrainment losses and product glass samples produced during the vendor tests. All vendors produced glasses that met minimum leach criteria established for the test glass formulations, although in many cases the waste oxide loading was less than intended. Entrainment was much lower in Joule-heated systems than in the combustion or plasma torch-fired systems. Volatility of alkali metals, halogens, B, Mo, and P were severe for non-Joule-heated systems. While losses of sulfur were significant for all systems, the volatility of other components was greatly reduced for some configurations of Joule-heated melters. Data on approaches to reduce NO{sub x} generation, resulting from high nitrate and nitrite content in the double-shell slurry feed, are also presented.

  4. Volatility and entrainment of feed components and product glass characteristics during pilot-scale vitrification of simulated Hanford site low-level waste

    SciTech Connect (OSTI)

    Shade, J.W.

    1996-05-03

    Commercially available melter technologies were tested for application to vitrification of Hanford site low-level waste (LLW). Testing was conducted at vendor facilities using a non-radioactive LLW simulant. Technologies tested included four Joule-heated melter types, a carbon electrode melter, a cyclone combustion melter, and a plasma torch-fired melter. A variety of samples were collected during the vendor tests and analyzed to provide data to support evaluation of the technologies. This paper describes the evaluation of melter feed component volatility and entrainment losses and product glass samples produced during the vendor tests. All vendors produced glasses that met minimum leach criteria established for the test glass formulations, although in many cases the waste oxide loading was less than intended. Entrainment was much lower in Joule-heated systems than in the combustion or plasma torch-fired systems. Volatility of alkali metals, halogens, B, Mo, and P were severe for non-Joule-heated systems. While losses of sulfur were significant for all systems, the volatility of other components was greatly reduced for some configurations of Joule-heated melters. Data on approaches to reduce NO{sub x} generation, resulting from high nitrate and nitrite content in the double-shell slurry feed, are also presented.

  5. Theoretical predictions of properties and volatility of chlorides and oxychlorides of group-4 elements. II. Adsorption of tetrachlorides and oxydichlorides of Zr, Hf, and Rf on neutral and modified surfaces

    SciTech Connect (OSTI)

    Pershina, V.; Borschevsky, A.; Iliaš, M.; Türler, A.

    2014-08-14

    With the aim to interpret results of gas-phase chromatography experiments on volatility of group-4 tetrachlorides and oxychlorides including those of Rf, adsorption enthalpies of these species on neutral, and modified quartz surfaces were estimated on the basis of relativistic, two-component Density Functional Theory calculations of MCl{sub 4}, MOCl{sub 2}, MCl{sub 6}{sup −}, and MOCl{sub 4}{sup 2} with the use of adsorption models. Several mechanisms of adsorption were considered. In the case of physisorption of MCl{sub 4}, the trend in the adsorption energy in the group should be Zr > Hf > Rf, so that the volatility should change in the opposite direction. The latter trend complies with the one in the sublimation enthalpies, ΔH{sub sub}, of the Zr and Hf tetrachlorides, i.e., Zr < Hf. On the basis of a correlation between these quantities, ΔH{sub sub}(RfCl{sub 4}) was predicted as 104.2 kJ/mol. The energy of physisorption of MOCl{sub 2} on quartz should increase in the group, Zr < Hf < Rf, as defined by increasing dipole moments of these molecules along the series. In the case of adsorption of MCl{sub 4} on quartz by chemical forces, formation of the MOCl{sub 2} or MOCl{sub 4}{sup 2−} complexes on the surface can take place, so that the sequence in the adsorption energy should be Zr > Hf > Rf, as defined by the complex formation energies. In the case of adsorption of MCl{sub 4} on a chlorinated quartz surface, formation of the MCl{sub 6}{sup 2−} surface complexes can occur, so that the trend in the adsorption strength should be Zr ≤ Hf < Rf. All the predicted sequences, showing a smooth change of the adsorption energy in the group, are in disagreement with the reversed trend Zr ≈ Rf < Hf, observed in the “one-atom-at-a-time” gas-phase chromatography experiments. Thus, currently no theoretical explanation can be found for the experimental observations.

  6. Emerging site characterization technologies for volatile organic compounds

    SciTech Connect (OSTI)

    Rohay, V.J.; Last, G.V.

    1992-05-01

    A Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) expedited response action (ERA) has been initiated at Hanford Site`s 200 West Area for the removal of carbon tetrachloride from the unsaturated soils. In coordination with the ERA, innovative technology demonstrations are being conducted as part of DOE`s Volatile Organic Compounds -- Arid Integrated Demonstration in an effort to improve upon baseline technologies. Improved methods for accessing, sampling, and analyzing soil and soil-vapor contaminants is a high priority. Sonic drilling is being evaluated as an alternative to cable-tool drilling, while still providing the advantages of reliability, containment, and waste minimization. Applied Research Associates, Inc. used their cone penetrometer in the 200 West Area to install a permanent soil-gas monitoring probe and to collect soil-gas profile data. However, successful application of this technology will require the development of an improved ability to penetrate coarse gravel units. A Science and Engineering Associates Membrane Instrumentation and Sampling Technique (SEAMIST) system designed for collecting in situ soil samples and air permeability data in between drilling runs at variable depths is being tested in 200 West Area boreholes. Analytical technologies scheduled for testing include supercritical fluid extraction and analysis for non- and semi-volatile organic co-contaminants and an unsaturated flow apparatus developed by Washington State University for the measurement of transport parameters.

  7. Emerging site characterization technologies for volatile organic compounds

    SciTech Connect (OSTI)

    Rohay, V.J.; Last, G.V.

    1992-05-01

    A Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) expedited response action (ERA) has been initiated at Hanford Site's 200 West Area for the removal of carbon tetrachloride from the unsaturated soils. In coordination with the ERA, innovative technology demonstrations are being conducted as part of DOE's Volatile Organic Compounds -- Arid Integrated Demonstration in an effort to improve upon baseline technologies. Improved methods for accessing, sampling, and analyzing soil and soil-vapor contaminants is a high priority. Sonic drilling is being evaluated as an alternative to cable-tool drilling, while still providing the advantages of reliability, containment, and waste minimization. Applied Research Associates, Inc. used their cone penetrometer in the 200 West Area to install a permanent soil-gas monitoring probe and to collect soil-gas profile data. However, successful application of this technology will require the development of an improved ability to penetrate coarse gravel units. A Science and Engineering Associates Membrane Instrumentation and Sampling Technique (SEAMIST) system designed for collecting in situ soil samples and air permeability data in between drilling runs at variable depths is being tested in 200 West Area boreholes. Analytical technologies scheduled for testing include supercritical fluid extraction and analysis for non- and semi-volatile organic co-contaminants and an unsaturated flow apparatus developed by Washington State University for the measurement of transport parameters.

  8. Spin Hall magnetoresistance in CoFe<sub>2sub>O>4sub>/Pt films

    SciTech Connect (OSTI)

    Wu, Hao; Qintong, Zhang; Caihua, Wan; Ali, Syed Shahbaz; Yuan, Zhonghui; You, Lu; Wang, Junling; Choi, Yongseong; Han, Xiufeng

    2015-05-13

    Pulse laser deposition and magnetron sputtering techniques have been employed to prepare MgO(001)//CoFe<sub>2sub>O>4sub>/Pt samples. Cross section transmission electron microscope results prove that the CoFe<sub>2sub>O>4sub> film epitaxially grew along (001) direction. X-ray magnetic circular dichroism results show that magnetic proximity effect in this sample is negligible. Magnetoresistance (MR) properties confirm that spin Hall MR (SMR) dominates in this system. Spin Hall effect-induced anomalous Hall voltage was also observed in this sample. Lastly, these results not only demonstrate the universality of SMR effect but also demonstrate the utility in spintronics of CoFe<sub>2sub>O>4sub> as a new type of magnetic insulator.

  9. Investigation of room temperature ferromagnetic nanoparticles of Gd<sub>5sub>Si>4sub>

    SciTech Connect (OSTI)

    Hadimani, R. L.; Gupta, S.; Harstad, S. M.; Pecharsky, V. K.; Jiles, D. C.

    2015-07-06

    Gd<sub>5sub>(SixGe>1-xsub>)>4sub> compounds undergo first-order phase transitions close to room temperature when x ~ = 0.5, which are accompanied by extreme changes of properties. We report the fabrication of the nanoparticles of one of the parent compounds-Gd<sub>5sub>Si>4sub>-using high-energy ball milling. Crystal structure, microstructure, and magnetic properties have been investigated. Particles agglomerate at long milling times, and the particles that are milled >20 min lose crystallinity and no longer undergo magnetic phase transition close to 340 K, which is present in a bulk material. The samples milled for >20 min exhibit a slightly increased coercivity. As a result, magnetization at a high temperature of 275K decreases with the increase in the milling time.

  10. Selective interlayer ferromagnetic coupling between the Cu spins in YBa<sub>2sub>Cu>3sub>O>7–xsub> grown on top of La<sub>0.7sub>Ca>0.3sub>MnO>3sub>

    SciTech Connect (OSTI)

    Huang, S. W.; Wray, L. Andrew; Jeng, Horng -Tay; Tra, V. T.; Lee, J. M.; Langner, M. C.; Chen, J. M.; Roy, S.; Chu, Y. H.; Schoenlein, R. W.; Chuang, Y. -D.; Lin, J. -Y.

    2015-11-17

    Studies to date on ferromagnet/d-wave superconductor heterostructures focus mainly on the effects at or near the interfaces while the response of bulk properties to heterostructuring is overlooked. Here we use resonant soft x-ray scattering spectroscopy to reveal a novel c-axis ferromagnetic coupling between the in-plane Cu spins in YBa<sub>2sub>Cu>3sub>O>7–xsub> (YBCO) superconductor when it is grown on top of ferromagnetic La<sub>0.7sub>Ca>0.3sub>MnO>3sub> (LCMO) manganite layer. This coupling, present in both normal and superconducting states of YBCO, is sensitive to the interfacial termination such that it is only observed in bilayers with MnO<sub>2sub> but not with La<sub>0.7sub>Ca>0.3sub>O interfacial termination. Thus, such contrasting behaviors, we propose, are due to distinct energetic of CuO chain and CuO<sub>2sub> plane at the La<sub>0.7sub>Ca>0.3sub>O and MnO<sub>2sub> terminated interfaces respectively, therefore influencing the transfer of spin-polarized electrons from manganite to cuprate differently. Our findings suggest that the superconducting/ferromagnetic bilayers with proper interfacial engineering can be good candidates for searching the theorized Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) state in cuprates and studying the competing quantum orders in highly correlated electron systems.

  11. Fermi surface measurements in YBa sub 2 Cu sub 3 O sub 7-x and La sub 1. 874 Sr sub. 126 CuO sub 4

    SciTech Connect (OSTI)

    Howell, R.H.; Sterne, P.A.; Solal, F.; Fluss, M.J. ); Haghighi, H.; Kaiser, J.H.; Rayner, S.L.; West, R.N. ); Liu, J.Z; Shelton, R. ); Kojima, H. ); Kitazawa, K. )

    1991-06-25

    We report new, ultra high precision measurements of the electron-positron momentum spectra of YBa{sub 2}Cu{sub 3}O{sub 7-x} and La{sub 1.874}Sr{sub 126}CuO{sub 4}. The YBCO experiments were performed on twin free, single crystals and show discontinuities with the symmetry of the Fermi surface of the CuO chain bands. Conduction band and underlying features in LSCO share the same symmetry and can only be separated with the aid of LDA calculations. 5 refs., 3 figs.

  12. High antiferromagnetic transition temperature of a honeycomb compound SrRu<sub>2sub>O>6sub>

    SciTech Connect (OSTI)

    Tian, Wei; Svoboda, Chris; Ochi, M.; Matsuda, M.; Cao, Huibo; Cheng, J. -G.; Sales, B. C.; Mandrus, D.; Arita, R.; Trivedi, Nandini; Yan, Jiaqiang

    2015-09-14

    We study the high-temperature magnetic order in a quasi-two-dimensional honeycomb compound SrRu<sub>2sub>O>6sub> by measuring magnetization and neutron powder diffraction with both polarized and unpolarized neutrons. SrRu<sub>2sub>O>6sub> crystallizes into the hexagonal lead antimonate (PbSb<sub>2sub>O>6sub>, space group P31m) structure with layers of edge-sharing RuO6 octahedra separated by Sr2+ ions. SrRu<sub>2sub>O>6sub> is found to order at T<sub>N> = 565 K with Ru moments coupled antiferromagnetically both in plane and out of plane. The magnetic moment is 1.30(2) ?<sub>B>/Ru at room temperature and is along the crystallographic c axis in the G-type magnetic structure. We perform density functional calculations with constrained random-phase approximation (RPA) to obtain the electronic structure and effective intra- and interorbital interaction parameters. The projected density of states shows strong hybridization between Ru 4d and O 2p. By downfolding to the target t<sub>2gsub> bands we extract the effective magnetic Hamiltonian and perform Monte Carlo simulations to determine the transition temperature as a function of interand intraplane couplings. We find a weak interplane coupling, 3% of the strong intraplane coupling, permits three-dimensional magnetic order at the observed T<sub>N> .

  13. Observation of the Decay B??D<sub>s(*)+K?l????l>

    SciTech Connect (OSTI)

    del Amo Sanchez, P.; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D. N.; Hooberman, B.; Kerth, L. T.; Kolomensky, Yu. G.; Lynch, G.; Osipenkov, I. L.; Tanabe, T.; Hawkes, C. M.; Watson, A. T.; Koch, H.; Schroeder, T.; Asgeirsson, D. J.; Hearty, C.; Mattison, T. S.; McKenna, J. A.; Khan, A.; Randle-Conde, A.; Blinov, V. E.; Buzykaev, A. R.; Druzhinin, V. P.; Golubev, V. B.; Onuchin, A. P.; Serednyakov, S. I.; Skovpen, Yu. I.; Solodov, E. P.; Todyshev, K. Yu.; Yushkov, A. N.; Bondioli, M.; Curry, S.; Kirkby, D.; Lankford, A. J.; Mandelkern, M.; Martin, E. C.; Stoker, D. P.; Atmacan, H.; Gary, J. W.; Liu, F.; Long, O.; Vitug, G. M.; Campagnari, C.; Hong, T. M.; Kovalskyi, D.; Richman, J. D.; Eisner, A. M.; Heusch, C. A.; Kroseberg, J.; Lockman, W. S.; Martinez, A. J.; Schalk, T.; Schumm, B. A.; Seiden, A.; Winstrom, L. O.; Cheng, C. H.; Doll, D. A.; Echenard, B.; Hitlin, D. G.; Ongmongkolkul, P.; Porter, F. C.; Rakitin, A. Y.; Andreassen, R.; Dubrovin, M. S.; Mancinelli, G.; Meadows, B. T.; Sokoloff, M. D.; Bloom, P. C.; Ford, W. T.; Gaz, A.; Nagel, M.; Nauenberg, U.; Smith, J. G.; Wagner, S. R.; Ayad, R.; Toki, W. H.; Jasper, H.; Karbach, T. M.; Merkel, J.; Petzold, A.; Spaan, B.; Wacker, K.; Kobel, M. J.; Schubert, K. R.; Schwierz, R.; Bernard, D.; Verderi, M.; Clark, P. J.; Playfer, S.; Watson, J. E.; Andreotti, M.; Bettoni, D.; Bozzi, C.; Calabrese, R.; Cecchi, A.; Cibinetto, G.; Fioravanti, E.; Franchini, P.; Luppi, E.; Munerato, M.; Negrini, M.; Petrella, A.; Piemontese, L.; Baldini-Ferroli, R.; Calcaterra, A.; de Sangro, R.; Finocchiaro, G.; Nicolaci, M.; Pacetti, S.; Patteri, P.; Peruzzi, I. M.; Piccolo, M.; Rama, M.; Zallo, A.; Contri, R.; Guido, E.; Lo Vetere, M.; Monge, M. R.; Passaggio, S.; Patrignani, C.; Robutti, E.; Tosi, S.; Bhuyan, B.; Prasad, V.; Lee, C. L.; Morii, M.; Adametz, A.; Marks, J.; Schenk, S.; Uwer, U.; Bernlochner, F. U.; Ebert, M.; Lacker, H. M.; Lueck, T.; Volk, A.; Dauncey, P. D.; Tibbetts, M.; Behera, P. K.; Mallik, U.; Chen, C.; Cochran, J.; Crawley, H. B.; Dong, L.; Meyer, W. T.; Prell, S.; Rosenberg, E. I.; Rubin, A. E.; Gao, Y. Y.; Gritsan, A. V.; Guo, Z. J.; Arnaud, N.; Davier, M.; Derkach, D.; Firmino da Costa, J.; Grosdidier, G.; Le Diberder, F.; Lutz, A. M.; Malaescu, B.; Perez, A.; Roudeau, P.; Schune, M. H.; Serrano, J.; Sordini, V.; Stocchi, A.; Wang, L.; Wormser, G.; Lange, D. J.; Wright, D. M.; Bingham, I.; Chavez, C. A.; Coleman, J. P.; Fry, J. R.; Gabathuler, E.; Gamet, R.; Hutchcroft, D. E.; Payne, D. J.; Touramanis, C.; Bevan, A. J.; Di Lodovico, F.; Sacco, R.; Sigamani, M.; Cowan, G.; Paramesvaran, S.; Wren, A. C.; Brown, D. N.; Davis, C. L.; Denig, A. G.; Fritsch, M.; Gradl, W.; Hafner, A.; Alwyn, K. E.; Bailey, D.; Barlow, R. J.; Jackson, G.; Lafferty, G. D.; West, T. J.; Anderson, J.; Cenci, R.; Jawahery, A.; Roberts, D. A.; Simi, G.; Tuggle, J. M.; Dallapiccola, C.; Salvati, E.; Cowan, R.; Dujmic, D.; Fisher, P. H.; Sciolla, G.; Zhao, M.; Lindemann, D.; Patel, P. M.; Robertson, S. H.; Schram, M.; Biassoni, P.; Lazzaro, A.; Lombardo, V.; Palombo, F.; Stracka, S.; Cremaldi, L.; Godang, R.; Kroeger, R.; Sonnek, P.; Summers, D. J.; Nguyen, X.; Simard, M.; Taras, P.; De Nardo, G.; Monorchio, D.; Onorato, G.; Sciacca, C.; Raven, G.; Snoek, H. L.; Jessop, C. P.; Knoepfel, K. J.; LoSecco, J. M.; Wang, W. F.; Corwin, L. A.; Honscheid, K.; Kass, R.; Morris, J. P.; Rahimi, A. M.; Blount, N. L.; Brau, J.; Frey, R.; Igonkina, O.; Kolb, J. A.; Rahmat, R.; Sinev, N. B.; Strom, D.; Strube, J.; Torrence, E.; Castelli, G.; Feltresi, E.; Gagliardi, N.; Margoni, M.; Morandin, M.; Posocco, M.; Rotondo, M.; Simonetto, F.; Stroili, R.; Ben-Haim, E.; Bonneaud, G. R.; Briand, H.; Calderini, G.; Chauveau, J.; Hamon, O.; Leruste, Ph.; Marchiori, G.; Ocariz, J.; Prendki, J.; Sitt, S.; Biasini, M.; Manoni, E.; Rossi, A.; Angelini, C.; Batignani, G.; Bettarini, S.; Carpinelli, M.; Casarosa, G.; Cervelli, A.; Forti, F.; Giorgi, M. A.; Lusiani, A.; Neri, N.; Paoloni, E.; Rizzo, G.; Walsh, J. J.; Lopes Pegna, D.; Lu, C.; Olsen, J.; Smith, A. J. S.; Telnov, A. V.; Anulli, F.; Baracchini, E.; Cavoto, G.; Faccini, R.; Ferrarotto, F.; Ferroni, F.; Gaspero, M.; Li Gioi, L.; Mazzoni, M. A.; Piredda, G.; Renga, F.; Hartmann, T.; Leddig, T.; Schrder, H.; Waldi, R.; Adye, T.; Franek, B.; Olaiya, E. O.; Wilson, F. F.; Emery, S.; Hamel de Monchenault, G.; Vasseur, G.; Yche, Ch.; Zito, M.; Allen, M. T.; Aston, D.; Bard, D. J.; Bartoldus, R.; Benitez, J. F.; Cartaro, C.; Convery, M. R.; Dorfan, J.; Dubois-Felsmann, G. P.; Dunwoodie, W.; Field, R. C.; Franco Sevilla, M.; Fulsom, B. G.; Gabareen, A. M.; Graham, M. T.; Grenier, P.; Hast, C.; Innes, W. R.

    2011-07-22

    We report the observation of the decay B??D<sub>s(*)+K?l??l> based on 342fb? of data collected at the ?(4S) resonance with the BABAR detector at the PEP-II e?e? storage rings at SLAC. A simultaneous fit to three D+s decay chains is performed to extract the signal yield from measurements of the squared missing mass in the B meson decay. We observe the decay B??D<sub>s(*)+K?l??l> with a significance greater than 5 standard deviations (including systematic uncertainties) and measure its branching fraction to be B(B??D<sub>s(*)+K?l??l>)=[6.13+1.04<sub>-1.03sub>(stat)0.43(syst)0.51(B(D<sub>s>))]10??, where the last error reflects the limited knowledge of the D<sub>s> branching fractions.

  14. Spontaneous formation of suboxidic coordination around Co in ferromagnetic rutile Ti<sub>0.95sub>Co>0.5sub>O>2sub> film

    SciTech Connect (OSTI)

    Hu, Wen; Hayaski, Kouichi; Fukumura, Tomoteru; Akagi, Kazuto; Tsukada, Masaru; Happo, Naohisa; Hosokawa, Shinya; Ohwada, Kenji; Takahasi, Masamitu; Suzuki, Motohiro

    2015-06-02

    To evaluate local atomic structures around Co in high temperature diluted ferromagnetic semiconductor Co-doped TiO<sub>2sub>, x-ray fluorescence holography and x-ray absorption fine structure experiments were carried out on rutile paramagnetic Ti<sub>0.99sub>Co>0.01sub>O>2sub> and ferromagnetic Ti<sub>0.95sub>Co>0.05sub>O>2sub> films. The Co atoms in the Ti<sub>0.99sub>Co>0.01sub>O>2sub> simply substituted for Ti sites in the rutile structure, whereas a suboxidic arrangement of CoO<sub>2sub>Ti>4sub> formed around Co in the Ti<sub>0.95sub>Co>0.05sub>O>2sub> films. A theoretical investigation based on a series of first-principles calculations indicated the stability of the aggregated suboxidic clusters in the rutile TiO<sub>2sub>, supporting our hypothesis for the formation of suboxidic coordination in the highly Co-doped sample. As a result, the suboxidic coordination may be the source of strong exchange interaction, resulting in the high Curie temperature in Co-doped TiO<sub>2sub>.

  15. Extraordinary selectivity of CoMo{sub 3}S{sub 13} chalcogel for C{sub 2}H{sub 6} and CO{sub 2} adsorption.

    SciTech Connect (OSTI)

    Shafaei-Fallah, M.; Rothenberger, Z.; Katsoulidis, A. P.; He, J.; Malliakas, C. D.; Kanatzidis, M. G.

    2011-11-09

    The chalcogel CoMo{sub 3}S{sub 13} is obtained from the reaction of (NH{sub 4}){sub 2}[Mo{sub 3}S{sub 13}] with cobalt acetate in solution. The chalcogel has a BET surface area of 570 m{sup 2} g{sup -1}, and pair distribution function analysis (PDF) and infrared spectroscopy indicate that the [Mo{sub 3}S{sub 13}]{sup 2-} cluster is a building block in the porous network. The CoMo{sub 3}S{sub 13} chalcogel exhibits high selectivity for separating ethane and carbon dioxide from hydrogen and methane.

  16. Stripe-like nanoscale structural phase separation in superconducting BaPb<sub>1-xsub>BixO>3sub>

    SciTech Connect (OSTI)

    Giraldo-Gallo, P.; Zhang, Y.; Parra, C.; Manoharan, H. C.; Beasley, M. R.; Geballe, T. H.; Kramer, M. J.; Fisher, I. R.

    2015-09-16

    The phase diagram of BaPb<sub>1-xsub>BixO>3sub> exhibits a superconducting “dome” in the proximity of a charge density wave phase. For the superconducting compositions, the material coexists as two structural polymorphs. Here we show, via high resolution transmission electron microscopy, that the structural dimorphism is accommodated in the form of partially disordered nanoscale stripes. Identification of the morphology of the nanoscale structural phase separation enables determination of the associated length scales, which we compare to the Ginzburg-Landau coherence length. Thus, we find that the maximum T<sub>c> occurs when the superconducting coherence length matches the width of the partially disordered stripes, implying a connection between the structural phase separation and the shape of the superconducting dome.

  17. Aqueous Sulfate Separation by Sequestration of [(SO<sub>4sub>)>2sub>(H>2sub>O)>4sub>]>4sub> Clusters within Highly Insoluble Imine-Linked Bis-Guanidinium Crystals

    SciTech Connect (OSTI)

    Custelcean, Radu; Williams, Neil J.; Seipp, Charles A.; Ivanov, Aleksandr; Bryantsev, Vyacheslav

    2015-12-18

    Quantitative removal of sulfate from seawater was achieved by selective crystallization of the anion with a bis(guanidinium) ligand self-assembled in situ through imine condensation of simple components. The resulting crystalline salt has an exceptionally low aqueous solubility, on a par with BaSO<sub>4sub>. Single-crystal X-ray diffraction analysis revealed pairs of sulfate anions clustered together with four water molecules within the crystals.

  18. Stabilized wide bandgap MAPbBr<sub>xI>3-xsub> perovskite by enhanced grain size and improved crystallinity

    SciTech Connect (OSTI)

    Hu, Miao; Bi, Cheng; Yuan, Yongbo; Bai, Yang; Huang, Jinsong

    2015-12-07

    In this study, the light instability of CH<sub>3sub>NH>3sub>PbIxBr>3xsub> has been raised one of the biggest challenges for its application in tandem solar cells. Here we show that an improved crystallinity and grain size of CH<sub>3sub>NH>3sub>PbIxBr>3xsub> films could stabilize these materials under one sun illumination, improving both the efficiency and stability of the wide-bandgap perovskite solar cells.

  19. Preparation of U.sub.3 O.sub.8

    DOE Patents [OSTI]

    Johnson, David R.

    1980-01-01

    A method is described for the preparation of U.sub.3 O.sub.8 nuclear fuel material by direct precipitation of uranyl formate monohydrate from uranyl nitrate solution. The uranyl formate monohydrate precipitate is removed, dried and calcined to produce U.sub.3 O.sub.8 having a controlled particle size distribution.

  20. A study of Zn<sub>xsub>ZryOz> mixed oxides for direct conversion of ethanol to isobutene

    SciTech Connect (OSTI)

    Liu, Changjun; Sun, Junming; Smith, Colin; Wang, Yong

    2013-07-15

    Zn<sub>xsub>ZryOz> mixed oxides were studied for direct conversion of ethanol to isobutene. Reaction conditions (temperature, residence time, ethanol molar fraction, steam to carbon ratio), catalyst composition, and pretreatment conditions were investigated, aiming at high-yield production of isobutene under industrially relevant conditions. An isobutene yield of 79% was achieved with an ethanol molar fraction of 8.3% at 475 °C on fresh Zn<sub>1sub>Zr>8sub>O>17sub> catalysts. Further durability and regeneration tests revealed that the catalyst exhibited very slow deactivation via coking formation with isobutene yield maintained above 75% for more than 10 h time-on-stream. More importantly, the catalysts activity in terms of isobutene yield can be readily recovered after in situ calcination in air at 550 °C for 2.5 h. XRD, TPO, IR analysis of adsorbed pyridine (IR-Py), and nitrogen sorption have been used to characterize the surface physical/chemical properties to correlate the structure and performance of the catalysts.

  1. Fluorocarbon assisted atomic layer etching of SiO<sub>2sub> and Si using cyclic Ar/C<sub>4sub>F>8sub> and Ar/CHF<sub>3sub> plasma

    SciTech Connect (OSTI)

    Metzler, Dominik; Li, Chen; Engelmann, Sebastian; Bruce, Robert L.; Joseph, Eric A.; Oehrlein, Gottlieb S.

    2015-11-11

    The need for atomic layer etching (ALE) is steadily increasing as smaller critical dimensions and pitches are required in device patterning. A flux-control based cyclic Ar/C<sub>4sub>F>8sub> ALE based on steady-state Ar plasma in conjunction with periodic, precise C<sub>4sub>F>8sub> injection and synchronized plasma-based low energy Ar+ ion bombardment has been established for SiO<sub>2sub>.1 In this work, the cyclic process is further characterized and extended to ALE of silicon under similar process conditions. The use of CHF<sub>3sub> as a precursor is examined and compared to C<sub>4sub>F>8sub>. CHF<sub>3sub> is shown to enable selective SiO<sub>2sub>/Si etching using a fluorocarbon (FC) film build up. Other critical process parameters investigated are the FC film thickness deposited per cycle, the ion energy, and the etch step length. Etching behavior and mechanisms are studied using in situ real time ellipsometry and X-ray photoelectron spectroscopy. Silicon ALE shows less self-limitation than silicon oxide due to higher physical sputtering rates for the maximum ion energies used in this work, ranged from 20 to 30 eV. The surface chemistry is found to contain fluorinated silicon oxide during the etching of silicon. As a result, plasma parameters during ALE are studied using a Langmuir probe and establish the impact of precursor addition on plasma properties.

  2. Detection of volatile organic compounds using surface enhanced Raman scattering

    SciTech Connect (OSTI)

    Chang, A S; Maiti, A; Ileri, N; Bora, M; Larson, C C; Britten, J A; Bond, T C

    2012-03-22

    The authors present the detection of volatile organic compounds directly in their vapor phase by surface-enhanced Raman scattering (SERS) substrates based on lithographically-defined two-dimensional rectangular array of nanopillars. The type of nanopillars is known as the tapered pillars. For the tapered pillars, SERS enhancement arises from the nanofocusing effect due to the sharp tip on top. SERS experiments were carried out on these substrates using various concentrations of toluene vapor. The results show that SERS signal from a toluene vapor concentration of ppm level can be achieved, and the toluene vapor can be detected within minutes of exposing the SERS substrate to the vapor. A simple adsorption model is developed which gives results matching the experimental data. The results also show promising potential for the use of these substrates in environmental monitoring of gases and vapors.

  3. In-Situ Contained And Of Volatile Soil Contaminants

    DOE Patents [OSTI]

    Varvel, Mark Darrell

    2005-12-27

    The invention relates to a novel approach to containing and removing toxic waste from a subsurface environment. More specifically the present invention relates to a system for containing and removing volatile toxic chemicals from a subsurface environment using differences in surface and subsurface pressures. The present embodiment generally comprises a deep well, a horizontal tube, at least one injection well, at least one extraction well and a means for containing the waste within the waste zone (in-situ barrier). During operation the deep well air at the bottom of well (which is at a high pressure relative to the land surface as well as relative to the air in the contaminated soil) flows upward through the deep well (or deep well tube). This stream of deep well air is directed into the horizontal tube, down through the injection tube(s) (injection well(s)) and into the contaminate plume where it enhances volatization and/or removal of the contaminants.

  4. Apparatus for sensing volatile organic chemicals in fluids

    DOE Patents [OSTI]

    Hughes, Robert C.; Manginell, Ronald P.; Jenkins, Mark W.; Kottenstette, Richard; Patel, Sanjay V.

    2005-06-07

    A chemical-sensing apparatus is formed from the combination of a chemical preconcentrator which sorbs and concentrates particular volatile organic chemicals (VOCs) and one or more chemiresistors that sense the VOCs after the preconcentrator has been triggered to release them in concentrated form. Use of the preconcentrator and chemiresistor(s) in combination allows the VOCs to be detected at lower concentration than would be possible using the chemiresistor(s) alone and further allows measurements to be made in a variety of fluids, including liquids (e.g. groundwater). Additionally, the apparatus provides a new mode of operation for sensing VOCs based on the measurement of decay time constants, and a method for background correction to improve measurement precision.

  5. In-Situ Containment and Extraction of Volatile Soil Contaminants

    DOE Patents [OSTI]

    Varvel, Mark Darrell

    2005-12-27

    The invention relates to a novel approach to containing and removing toxic waste from a subsurface environment. More specifically the present invention relates to a system for containing and removing volatile toxic chemicals from a subsurface environment using differences in surface and subsurface pressures. The present embodiment generally comprises a deep well, a horizontal tube, at least one injection well, at least one extraction well and a means for containing the waste within the waste zone (in-situ barrier). During operation the deep well air at the bottom of well (which is at a high pressure relative to the land surface as well as relative to the air in the contaminated soil) flows upward through the deep well (or deep well tube). This stream of deep well air is directed into the horizontal tube, down through the injection tube(s) (injection well(s)) and into the contaminate plume where it enhances volatization and/or removal of the contaminants.

  6. System for loading executable code into volatile memory in a downhole tool

    DOE Patents [OSTI]

    Hall, David R.; Bartholomew, David B.; Johnson, Monte L.

    2007-09-25

    A system for loading an executable code into volatile memory in a downhole tool string component comprises a surface control unit comprising executable code. An integrated downhole network comprises data transmission elements in communication with the surface control unit and the volatile memory. The executable code, stored in the surface control unit, is not permanently stored in the downhole tool string component. In a preferred embodiment of the present invention, the downhole tool string component comprises boot memory. In another embodiment, the executable code is an operating system executable code. Preferably, the volatile memory comprises random access memory (RAM). A method for loading executable code to volatile memory in a downhole tool string component comprises sending the code from the surface control unit to a processor in the downhole tool string component over the network. A central processing unit writes the executable code in the volatile memory.

  7. Dual nature of 3 d electrons in YbT <sub>2sub> Zn <sub>20sub> (T = Co; Fe) evidenced by electron spin resonance

    SciTech Connect (OSTI)

    Ivanshin, V. A.; Litvinova, T. O.; Gimranova, K.; Sukhanov, A. A.; Jia, S.; Bud'ko, S. L.; Canfield, P. C.

    2015-03-18

    The electron spin resonance experiments were carried out in the single crystals YbFe<sub>2sub>Zn>20sub>. The observed spin dynamics is compared with that in YbCo<sub>2sub>Zn>20sub> and Yb<sub>2sub>Co>12sub>P>7sub> as well as with the data of inelastic neutron scattering and electronic band structure calculations. Our results provide direct evidence that 3d electrons are itinerant in YbFe<sub>2sub>Zn>20sub> and localized in YbCo<sub>2sub>Zn>20sub>. Possible connection between spin paramagnetism of dense heavy fermion systems, quantum criticality effects, and ESR spectra is discussed.

  8. A Big Data Approach to Analyzing Market Volatility

    SciTech Connect (OSTI)

    Wu, Kesheng; Bethel, E. Wes; Gu, Ming; Leinweber, David; Ruebel, Oliver

    2013-06-05

    Understanding the microstructure of the financial market requires the processing of a vast amount of data related to individual trades, and sometimes even multiple levels of quotes. Analyzing such a large volume of data requires tremendous computing power that is not easily available to financial academics and regulators. Fortunately, public funded High Performance Computing (HPC) power is widely available at the National Laboratories in the US. In this paper we demonstrate that the HPC resource and the techniques for data-intensive sciences can be used to greatly accelerate the computation of an early warning indicator called Volume-synchronized Probability of Informed trading (VPIN). The test data used in this study contains five and a half year?s worth of trading data for about 100 most liquid futures contracts, includes about 3 billion trades, and takes 140GB as text files. By using (1) a more efficient file format for storing the trading records, (2) more effective data structures and algorithms, and (3) parallelizing the computations, we are able to explore 16,000 different ways of computing VPIN in less than 20 hours on a 32-core IBM DataPlex machine. Our test demonstrates that a modest computer is sufficient to monitor a vast number of trading activities in real-time ? an ability that could be valuable to regulators. Our test results also confirm that VPIN is a strong predictor of liquidity-induced volatility. With appropriate parameter choices, the false positive rates are about 7percent averaged over all the futures contracts in the test data set. More specifically, when VPIN values rise above a threshold (CDF > 0.99), the volatility in the subsequent time windows is higher than the average in 93percent of the cases.

  9. CaMn<sub>2sub>Al>10sub>: Itinerant Mn magnetism on the verge of magnetic order

    SciTech Connect (OSTI)

    Steinke, L.; Simonson, J. W.; Yin, W. -G.; Smith, G. J.; Kistner-Morris, J. J.; Zellman, S.; Puri, A.; Aronson, M. C.

    2015-07-24

    We report the discovery of CaMn<sub>2sub>Al>10sub>, a metal with strong magnetic anisotropy and moderate electronic correlations. Magnetization measurements find a Curie-Weiss moment of 0.83<sub>μB>/Mn, significantly reduced from the Hund's rule value, and the magnetic entropy obtained from specific heat measurements is correspondingly small, only ≈ 9% of Rln2. These results imply that the Mn magnetism is highly itinerant, a conclusion supported by density functional theory calculations that find strong Mn-Al hybridization. Consistent with the layered nature of the crystal structure, the magnetic susceptibility χ is anisotropic below 20 K, with a maximum ratio of χ<sub>[010]sub>/χ>[001]sub> ≈ 3.5. A strong power-law divergence χ(T) ~ T–1.2 below 20 K implies incipient ferromagnetic order, an Arrott plot analysis of the magnetization suggests a vanishing low Curie temperature T<sub>C> ~ 0. Our experiments indicate that CaMn<sub>2sub>Al>10sub> is a rare example of a system where the weak and itinerant Mn-based magnetism is poised on the verge of order.

  10. Defect-Tolerant Diffusion Channels for Mg2+ Ions in Ribbon-Type Borates: Structural Insights into Potential Battery Cathodes MgVBO<sub>4sub> and Mg<sub>x> Fe<sub>2–xsub>B>2sub>O>5sub>

    SciTech Connect (OSTI)

    Bo, Shou-Hang; Grey, Clare P.; Khalifah, Peter G.

    2015-06-10

    The reversible room temperature intercalation of Mg2+ ions is difficult to achieve, but may offer substantial advantages in the design of next-generation batteries if this electrochemical process can be successfully realized. Two types of quadruple ribbon-type transition metal borates (Mg<sub>xFe>2-xsub>B>2sub>O>5sub> and MgVBO<sub>4sub>) with high theoretical capacities (186 mAh/g and 360 mAh/g) have been synthesized and structurally characterized through the combined Rietveld refinement of synchrotron and time-of-flight neutron diffraction data. Neither MgVBO<sub>4 sub> nor Mg<sub>xFe>2-xsub>B>2sub>O>5sub> can be chemically oxidized at room temperature, though Mg can be dynamically removed from the latter phase at elevated temperatures (approximately 200 - 500 °C). Findings show that Mg diffusion in the Mg<sub>xFe>2-xsub>B>2sub>O>5sub> structure is more facile for the inner two octahedral sites than for the two outer octahedral sites in the ribbons, a result supported by both the refined site occupancies after Mg removal and by bond valence sum difference map calculations of diffusion paths in the pristine material. Mg diffusion in this pyroborate Mg<sub>xFe>2-xsub>B>2sub>O>5sub> framework is also found to be tolerant to the presence of Mg/Fe disorder since Mg ions can diffuse through interstitial channels which bypass Fe-containing sites.

  11. Controlled peak wavelength shift of Ca{sub 1-} {sub x} Sr {sub x} (S {sub y} Se{sub 1-} {sub y} ):Eu{sup 2+} phosphor for LED application

    SciTech Connect (OSTI)

    Nazarov, Mihail . E-mail: nazarov.mihail@samsung.com; Yoon, Chulsoo

    2006-08-15

    The highly efficient red-orange-yellow-emitting phosphor (Ca{sub 1-} {sub x} Sr {sub x} )(S{sub 1-} {sub y} Se {sub y} ):Eu{sup 2+} in combination with commercial green phosphor SrGa{sub 2}S{sub 4}:Eu{sup 2+} and blue LED are proposed for a three-band white LED. The luminescence mechanism and optimization parameters are discussed on the basis of proposed peak wavelength diagram. - Graphical abstract: 'Peak wavelength diagram for (Ca{sub 1-} {sub x} Sr {sub x} )(S{sub 1-} {sub y} Se {sub y} ):Eu{sup 2+}'.

  12. CF.sub.4 laser

    DOE Patents [OSTI]

    Wittig, Curt; Tiee, Joe J.

    1979-01-01

    A CF.sub.4 laser for producing near 16 .mu.m radiation utilizing a line tunable CO.sub.2 laser as an optical pumping source. The device uses a cryogenically cooled optically pumped cell containing molecular CF.sub.4 gas. An optical resonant cavity formed around the optically pumped cell induces oscillations of near 16 .mu.m radiation from the .nu..sub.2 +.nu..sub.4 .fwdarw..nu..sub.2 transition in the molecular CF.sub.4 gas.

  13. Magnetic structures of β{sub I}-Li{sub 2}CoSiO{sub 4} and γ{sub 0}-Li{sub

    Office of Scientific and Technical Information (OSTI)

    2}MnSiO{sub 4}: Crystal structure type vs. magnetic topology (Journal Article) | SciTech Connect Magnetic structures of β{sub I}-Li{sub 2}CoSiO{sub 4} and γ{sub 0}-Li{sub 2}MnSiO{sub 4}: Crystal structure type vs. magnetic topology Citation Details In-Document Search Title: Magnetic structures of β{sub I}-Li{sub 2}CoSiO{sub 4} and γ{sub 0}-Li{sub 2}MnSiO{sub 4}: Crystal structure type vs. magnetic topology The magnetic structure and properties of the candidate lithium-ion battery cathode

  14. Multi-functional ultrathin Pd<sub>xCu>1-xsub> and Pt~Pd<sub>xCu>1-xsub> one-dimensional nanowire motifs for various small molecule oxidation reactions

    SciTech Connect (OSTI)

    Liu, Haiqing; Wong, Stanislaus S.; Adzic, Radoslav R.

    2015-11-18

    Developing novel electrocatalysts for small molecule oxidation processes, including formic acid oxidation (FAOR), methanol oxidation reaction (MOR), and ethanol oxidation reaction (EOR), denoting the key anodic reactions for their respective fuel cell configurations, is a significant and relevant theme of recent efforts in the field. Herein, in this report, we demonstrated a concerted effort to couple and combine the benefits of small size, anisotropic morphology, and tunable chemical composition in order to devise a novel “family” of functional architectures. In particular, we have fabricated not only ultrathin 1-D Pd<sub>1–xsub>Cux> alloys but also Pt-coated Pd<sub>1–xsub>Cux> (i.e., Pt~Pd<sub>1–xsub>Cux>; herein the ~ indicates an intimate association, but not necessarily actual bond formation, between the inner bimetallic core and the Pt outer shell) core–shell hierarchical nanostructures with readily tunable chemical compositions by utilizing a facile, surfactant-based, wet chemical synthesis coupled with a Cu underpotential deposition technique. Our main finding is that our series of as-prepared nanowires are functionally flexible. More precisely, we demonstrate that various examples within this “family” of structural motifs can be tailored for exceptional activity with all 3 of these important electrocatalytic reactions. In particular, we note that our series of Pd<sub>1–xsub>Cux> nanowires all exhibit enhanced FAOR activities as compared with not only analogous Pd ultrathin nanowires but also commercial Pt and Pd standards, with Pd<sub>9sub>Cu representing the “optimal” composition. Moreover, our group of Pt~Pd<sub>1–xsub>Cux> nanowires consistently outperformed not only commercial Pt NPs but also ultrathin Pt nanowires by several fold orders of magnitude for both the MOR and EOR reactions in alkaline media. As a result, the variation of the MOR and EOR performance with the chemical composition of our ultrathin Pt~Pd<sub>1–xsub>Cux> nanowires was also discussed.

  15. Structural and magnetic phase transitions in CeCu<sub>6-xsub>Tx> (T = Ag,Pd)

    SciTech Connect (OSTI)

    Poudel, Lekhanath N.; De la cruz, Clarina; Payzant, E. Andrew; Koehler, Michael R.; May, Andrew F.; Garlea, Vasile O.; Taylor, Alice E.; Parker, David S.; Cao, Huibo B.; McGuire, Michael A.; Tian, Wei; Matsuda, Masaaki; Jeen, Hyoung Jeen; Lee, Ho Nyung; Hong, Tao; Calder, Stuart A.; Lumsden, Mark D.; Zhou, Haidong; Keppens, Veerle; Mandrus, D.; Christianson, Andrew D.

    2015-12-15

    The structural and the magnetic properties of CeCu<sub>6-xsub>Agx> (0 ≤ x ≤ 0.85) and CeCu<sub>6-xsub>Pdx> (0 ≤ x ≤ 0.4) have been studied using neutron diffraction, resonant ultrasound spectroscopy (RUS), x-ray diffraction measurements, and first principles calculations. The structural and magnetic phase diagrams of CeCu<sub>6-xsub>Agx> and CeCu<sub>6-xsub>Pdx> as a function of Ag/Pd composition are reported. The end member, CeCu<sub>6sub>, undergoes a structural phase transition from an orthorhombic (Pnma) to a monoclinic (P2<sub>1sub>/c) phase at 240 K. In CeCu<sub>6-xsub>Agx>, the structural phase transition temperature (T<sub>s>) decreases linearly with Ag concentration and extrapolates to zero at x<sub>S> ≈ 0.1. The structural transition in CeCu<sub>6-xsub>Pdx> remains unperturbed with Pd substitution within the range of our study. The lattice constant b slightly decreases with Ag/Pd doping, whereas a and c increase with an overall increase in the unit cell volume. Both systems, CeCu<sub>6-xsub>Agx> and CeCu<sub>6-xsub>Pdx>, exhibit a magnetic quantum critical point (QCP), at x ≈ 0.2 and x ≈ 0.05, respectively. Near the QCP, long range antiferromagnetic ordering takes place at an incommensurate wave vector (δ<sub>1sub> 0 δ<sub>2sub>), where δ<sub>1sub> ~ 0.62, δ<sub>2sub> ~ 0.25, x = 0.125 for CeCu<sub>6-xsub>Pdx> and δ<sub>1sub> ~ 0.64, δ<sub>2sub> ~ 0.3, x = 0.3 for CeCu<sub>6-xsub>Agx>. As a result, the magnetic structure consists of an amplitude modulation of the Ce moments which are aligned along the c axis of the orthorhombic unit cell.

  16. Large single crystal quaternary alloys of IB-IIIA-SE.sub.2 and methods of synthesizing the same

    DOE Patents [OSTI]

    Ciszek, Theodore F.

    1988-01-01

    New alloys of Cu.sub.x Ag.sub.(1-x) InSe.sub.2 (where x ranges between 0 and 1 and preferably has a value of about 0.75) and CuIn.sub.y Ga.sub.(1-y) Se.sub.2 (where y ranges between 0 and 1 and preferably has a value of about 0.90) in the form of single crystals with enhanced structure perfection, which crystals are substantially free of fissures are disclosed. Processes are disclosed for preparing the new alloys of Cu.sub.x Ag.sub.(1-x) InSe.sub.2. The process includes placing stoichiometric quantities of a Cu, Ag, In, and Se reaction mixture or stoichiometric quantities of a Cu, In, Ga, and Se reaction mixture in a refractory crucible in such a manner that the reaction mixture is surrounded by B.sub.2 O.sub.3, placing the thus loaded crucible in a chamber under a high pressure atmosphere of inert gas to confine the volatile Se to the crucible, and heating the reaction mixture to its melting point. The melt can then be cooled slowly to form, by direct solidification, a single crystal with enhanced structure perfection, which crystal is substantially free of fissures.

  17. Large single crystal quaternary alloys of IB-IIIA-Se/sub 2/ and methods of synthesizing the same

    DOE Patents [OSTI]

    Ciszek, T.F.

    1986-07-15

    New alloys of Cu/sub x/Ag/sub (1-x)/InSe/sub 2/ (where x ranges between 0 and 1 and preferably has a value of about 0.75) and CuIn/sub y/Ga/sub (1-y)/Se/sub 2/ (where y ranges between 0 and 1 and preferably has a value of about 0.90) in the form of single crystals with enhanced structure perfection, which crystals are substantially free of fissures, are disclosed. Processes are disclosed for preparing the new alloys of Cu/sub x/Ag/sub (1-x)/InSe/sub 2/. The process includes placing stoichiometric quantities of a Cu, Ag, In, and Se reaction mixture or stoichiometric quantities of a Cu, In, Ga, and Se reaction mixture in a refractory crucible in such a manner that the reaction mixture is surrounded by B/sub 2/O/sub 3/, placing the thus loaded crucible in a chamber under a high pressure atmosphere of inert gas to confine the volatile Se to the crucible, and heating the reaction mixture to its melting point. The melt can then be cooled slowly to form, by direct solidification, a single crystal with enhanced structure perfection, which crystal is substantially free of fissures.

  18. SO<sub>2sub>-Resistant Immobilized Amine Sorbents for CO<sub>2sub> Capture

    SciTech Connect (OSTI)

    Tumuluri, Uma

    2014-01-01

    The solid amine sorbent for CO<sub>2sub> capture process has advantages of simplicity and low operating cost compared to the MEA (monoethanolamine) process. Solid amine sorbents reported so far suffered from either low CO<sub>2sub> capture capacity or low stability in the flue gas environment. This project is aimed at developing a SO<sub>2sub>-resistant solid amine sorbent for capturing CO<sub>2sub> from coalfired power plants with SCR/FGD which emits SO<sub>2sub>ranging from 15 to 30 ppm and NO ranging from 5 to 10 ppm. The amine sorbent we developed in a previous project degraded rapidly with 65% decrease in the initial capture capacity in presence of 1% SO<sub>2sub>. This amine sorbent was further modified by coating with polyethyleneglycol (PEG) to increase the SO<sub>2sub>-resistance. Polyethylene glycol (PEG) was found to decrease the SO<sub>2sub>-amine interaction, resulting in the decrease in the maximum SO desorption temperature (Tmax ) of amine sorbent. The PEG-coated amine sorbent exhibited higher stability with only 40% decrease in the initial capture capacity compared to un-coated amine sorbents. The cost of the solid amine sorbent developed in this project is estimated to be less than $7.00/lb; the sorbent exhibited CO<sub>2sub> capture capacity more than 2.3 mmol/g. The results of this study provided the scientific basis for further development of SO<sub>2sub>-resistant sorbents.

  19. Influence of defects on the charge density wave of ([SnSe]<sub>1+?sub>)>1sub>(VSe>2sub>)>1sub> ferecrystals

    SciTech Connect (OSTI)

    Falmbigl, Matthias; Putzky, Daniel; Ditto, Jeffrey; Esters, Marco; Bauers, Sage R.; Ronning, Filip; Johnson, David C.

    2015-07-14

    A series of ferecrystalline compounds ([SnSe]<sub>1+?sub>)>1sub>(VSe>2sub>)>1sub> with varying Sn/V ratios were synthesized using the modulated elemental reactant technique. Temperature-dependent specific heat data reveal a phase transition at 102 K, where the heat capacity changes abruptly. An abrupt increase in electrical resistivity occurs at the same temperature, correlated with an abrupt increase in the Hall coefficient. Combined with the magnitude and nature of the specific heat discontinuity, this suggests that the transition is similar to the charge density wave transitions in transition metal dichalcogenides. An ordered intergrowth was formed over a surprisingly wide compositional range of Sn/V ratios of 0.89 ? 1 + ? ? 1.37. X-ray diffraction and transmission electron microscopy reveal the formation of various volume defects in the compounds in response to the nonstoichiometry. The electrical resistivity and Hall coefficient data of samples with different Sn/V ratios show systematic variation in the carrier concentration with the Sn/V ratio. There is no significant change in the onset temperature of the charge density wave transition, only a variation in the carrier densities before and after the transition. Given the sensitivity of the charge density wave transitions of transition metal dichalcogenides to variations in composition, it is very surprising that the charge density wave transition observed at 102 K for ([SnSe]<sub>1.15sub>)>1sub>(VSe>2sub>)>1sub> is barely influenced by the nonstoichiometry and structural defects. As a result, this might be a consequence of the two-dimensional nature of the structurally independent VSe<sub>2sub> layers.

  20. Solvate Structures and Computational/Spectroscopic Characterization of LiBF<sub>4sub> Electrolytes

    SciTech Connect (OSTI)

    Seo, D. M.; Boyle, Paul D.; Allen, Joshua L.; Han, Sang D.; Jonsson, Erlendur; Johansson, Patrik; Henderson, Wesley A.

    2014-07-21

    Crystal structures have been determined for both LiBF<sub>4sub> and HBF<sub>4sub> solvates—(acetonitrile)<sub>2sub>:LiBF>4sub>, (ethylene glycol diethyl ether)<sub>1sub>:LiBF>4sub>, (diethylene glycol diethyl ether)1:LiBF<sub>4sub>, (tetrahydrofuran)<sub>1sub>:LiBF4, (methyl methoxyacetate)<sub>1sub>:LiBF>4sub>, (suc-cinonitrile)<sub>1sub>:LiBF>4sub>, (N,N,N',N",N"-pentamethyldiethylenetriamine)1:HBF<sub>4sub>, (N,N,N',N'-tetramethylethylenediamine)<sub>3/2sub>:HBF>4sub> and (phenanthroline)<sub>2sub>:HBF>4sub>. These, as well as other known LiBF<sub>4sub> solvate structures, have been characterized by Raman vibrational spectroscopy to unambiguously assign the anion Raman band positions to specific forms of BF<sub>4sub>-...Li+ cation coordination. In addition, complementary DFT calculations of BF<sub>4sub>-...Li+ cation complexes have provided additional insight into the challenges associated with accurately interpreting the anion interactions from experimental Raman spectra. This information provides a crucial tool for the characterization of the ionic association interactions within electrolytes.

  1. Epitaxial YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}/Sr{sub 2}RuO{sub 4} heterostructures

    SciTech Connect (OSTI)

    Schlom, D.G.; Merritt, B.A.; Madhavan, S. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering] [and others

    1997-09-01

    The anisotropic oxide superconductors YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} and Sr{sub 2}RuO{sub 4} have been epitaxially combined in various ways (c-axis on c-axis, c-axis on a-axis, and a-axis on a-axis) though the use of appropriate substrates. Phase-pure a-axis oriented or c-axis oriented epitaxial Sr{sub 2}RuO{sub 4} films were grown by pulsed laser deposition. YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films were then grown on both orientations of Sr{sub 2}RuO{sub 4} films and the resulting epitaxy was characterized.

  2. Insight into the Atomic Structure of High-Voltage Spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> Cathode Material in the First Cycle

    SciTech Connect (OSTI)

    Huang, Xuejie; Yu, Xiqian; Lin, Mingxiang; Ben, Liubin; Sun, Yang; Wang, Hao; Yang, Zhenzhong; Gu, Lin; Yang, Xiao -Qing; Zhao, Haofei; Yu, Richeng; Armand, Michel

    2014-12-22

    Application of high-voltage spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material is the closest and the most realistic approach to meeting the midterm goal of lithium-ion batteries for electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs). However, this application has been hampered by long-standing issues, such as capacity degradation and poor first-cycle Coulombic efficiency of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Although it is well-known that the structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> into which Li ions are reversibly intercalated plays a critical role in the above issues, performance degradation related to structural changes, particularly in the first cycle, are not fully understood. Here, we report detailed investigations of local atomic-level and average structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> during first cycle (3.5–4.9 V) at room temperature. We observed two types of local atomic-level migration of transition metals (TM) ions in the cathode of a well-prepared LiNi<sub>0.5sub>Mn>1.5sub>O>4sub>//Li half-cell during first charge via an aberration-corrected scanning transmission electron microscopy (STEM). Surface regions (~2 nm) of the cycled LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> particles show migration of TM ions into tetrahedral Li sites to form a Mn<sub>3sub>O>4sub>-like structure. However, subsurface regions of the cycled particles exhibit migration of TM ions into empty octahedral sites to form a rocksalt-like structure. The migration of these TM ions are closely related to dissolution of Ni/Mn ions and building-up of charge transfer impedance, which contribute significantly to the capacity degradation and the poor first-cycle Coulombic efficiency of spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Accordingly, we provide suggestions of effective stabilization of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> structure to obtain better electrochemical performance.

  3. Insight into the Atomic Structure of High-Voltage Spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> Cathode Material in the First Cycle

    SciTech Connect (OSTI)

    Huang, Xuejie; Yu, Xiqian; Lin, Mingxiang; Ben, Liubin; Sun, Yang; Wang, Hao; Yang, Zhenzhong; Gu, Lin; Yang, Xiao -Qing; Zhao, Haofei; Yu, Richeng; Armand, Michel

    2014-12-22

    Application of high-voltage spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material is the closest and the most realistic approach to meeting the midterm goal of lithium-ion batteries for electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs). However, this application has been hampered by long-standing issues, such as capacity degradation and poor first-cycle Coulombic efficiency of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Although it is well-known that the structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> into which Li ions are reversibly intercalated plays a critical role in the above issues, performance degradation related to structural changes, particularly in the first cycle, are not fully understood. Here, we report detailed investigations of local atomic-level and average structure of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> during first cycle (3.54.9 V) at room temperature. We observed two types of local atomic-level migration of transition metals (TM) ions in the cathode of a well-prepared LiNi<sub>0.5sub>Mn>1.5sub>O>4sub>//Li half-cell during first charge via an aberration-corrected scanning transmission electron microscopy (STEM). Surface regions (~2 nm) of the cycled LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> particles show migration of TM ions into tetrahedral Li sites to form a Mn<sub>3sub>O>4sub>-like structure. However, subsurface regions of the cycled particles exhibit migration of TM ions into empty octahedral sites to form a rocksalt-like structure. The migration of these TM ions are closely related to dissolution of Ni/Mn ions and building-up of charge transfer impedance, which contribute significantly to the capacity degradation and the poor first-cycle Coulombic efficiency of spinel LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> cathode material. Accordingly, we provide suggestions of effective stabilization of LiNi<sub>0.5sub>Mn>1.5sub>O>4sub> structure to obtain better electrochemical performance.

  4. Multiband Te p Based Superconductivity of Ta<sub>4sub>Pd>3sub>Te>16sub>

    SciTech Connect (OSTI)

    Singh, David J.

    2014-10-06

    We recently discovered that Ta<sub>4sub>Pd>3sub>Te>16 is a superconductor that has been suggested to be an unconventional superconductor near msub>agnetism. Here, we report electronic structure calculations showing that despite the layered crystal structure the material is an anisotropic three-dimensional (3D) metal. The Fermi surface contains prominent one-dimensional (1D) and two-dimensional (2D) features, including nested 1D sheets, a 2D cylindrical section, and a 3D sheet. Moreover, the electronic states that make up the Fermi surface are mostly derived from Te p states with small Ta d and Pd d contributions. This places the compound far from magnetic instabilities. The results are discussed in terms of multiband superconductivity.

  5. Negative to positive magnetoresistance and magnetocaloric effect in Pr<sub>0.6sub>Er>0.4sub>Al>2sub>

    SciTech Connect (OSTI)

    Pathak, Arjun K.; Gschneidner, Jr., K. A.; Pecharsky, V. K.

    2014-10-13

    We report on the magnetic, magnetocaloric and magnetotransport properties of Pr<sub>0.6sub>Er>0.4sub>Al>2sub>. The title compound exhibits a large positive magnetoresistance (MR) for H ≥ 40 kOe and a small but non negligible negative MR for H ≤ 30 kOe. The maximum positive MR reaches 13% at H = 80 kOe. The magnetic entropy and adiabatic temperature changes as functions of temperature each show two anomalies: a broad dome-like maximum below 20 K and a relatively sharp peak at higher temperature. As a result, observed behaviors are unique among other binary and mixed lanthanide compounds.

  6. Alternating magnetic anisotropy of Li<sub>2sub>(Li>1xsub>Tx>)N (T = Mn, Fe, Co, and Ni)

    SciTech Connect (OSTI)

    Jesche, A.; Ke, L.; Jacobs, J. L.; Harmon, B.; Houk, R. S.; Canfield, P. C.

    2015-05-11

    Substantial amounts of the transition metals Mn, Fe, Co, and Ni can be substituted for Li in single crystalline Li<sub>2sub>(Li>1xsub>Tx>)N. Isothermal and temperature-dependent magnetization measurements reveal local magnetic moments with magnitudes significantly exceeding the spin-only value. The additional contributions stem from unquenched orbital moments that lead to rare-earth-like behavior of the magnetic properties. Accordingly, extremely large magnetic anisotropies have been found. Most notably, the magnetic anisotropy alternates as easy plane?easy axis?easy plane?easy axis when progressing from T = Mn ? Fe ? Co ? Ni. This behavior can be understood based on a perturbation approach in an analytical, single-ion model. As a result, the calculated magnetic anisotropies show surprisingly good agreement with the experiment and capture the basic features observed for the different transition metals.

  7. Density functional theory calculations of magnetocrystalline anisotropy energies for (Fe<sub>1-xsub>Cox)>2sub>B

    SciTech Connect (OSTI)

    Daene, Markus; Kim, Soo Kyung; Surh, Michael P.; Aberg, Daniel; Benedict, Lorin X.

    2015-06-15

    We present and discuss density functional theory calculations of magnetic properties of the family of ferromagnetic compounds, (Fe<sub>1-xsub>Cox)>2sub>B, focusing specifically on the magnetocrystalline anisotropy energy (MAE). Using periodic supercells of various sizes (up to 96 atoms), it is shown that the general qualitative features of the composition dependence of the MAE is in agreement with experimental findings, while our predicted magnitudes are larger than those of experiment. We find that the use of small supercells (6 and 12-atom) favors larger MAE values relative to a statistical sample of configurations constructed with 96-atom supercells. As a result, the effect of lattice relaxations is shown to be small. Calculations of the Curie temperature for this alloy are also presented.

  8. Final Report - Glass Formulation Testing to Increase Sulfate Volatilization from Melter, VSL-04R4970-1, Rev. 0, dated 2/24/05

    SciTech Connect (OSTI)

    Kruger, Albert A.; Matlack, K. A.; Pegg, I. L.; Gong, W.

    2013-11-13

    The principal objectives of the DM100 and DM10 tests were to determine the impact of four different organics and one inorganic feed additive on sulfate volatilization and to determine the sulfur partitioning between the glass and the off-gas system. The tests provided information on melter processing characteristics and off-gas data including sulfur incorporation and partitioning. A series of DM10 and DM100 melter tests were conducted using a LAW Envelope A feed. The testing was divided into three parts. The first part involved a series of DM10 melter tests with four different organic feed additives: sugar, polyethylene glycol (PEG), starch, and urea. The second part involved two confirmatory 50-hour melter tests on the DM100 using the best combination of reductants and conditions based on the DM10 results. The third part was performed on the DM100 with feeds containing vanadium oxide (V{sub 2}O{sub 5}) as an inorganic additive to increase sulfur partitioning to the off-gas. Although vanadium oxide is not a reductant, previous testing has shown that vanadium shows promise for partitioning sulfur to the melter exhaust, presumably through its known catalytic effect on the SO{sub 2}/SO{sub 3} reaction. Crucible-scale tests were conducted prior to the melter tests to confirm that the glasses and feeds would be processable in the melter and that the glasses would meet the waste form (ILAW) performance requirements. Thus, the major objectives of these tests were to: ? Perform screening tests on the DM10 followed by tests on the DM100-WV system using a LAW -Envelope A feed with four organic additives to assess their impact on sulfur volatilization. ? Perform tests on the DM100-WV system using a LAW -Envelope A feed containing vanadium oxide to assess its impact on sulfur volatilization. ? Determine feed processability and product quality with the above additives. ? Collect melter emissions data to determine the effect of additives on sulfur partitioning and melter emissions. ? Collect and analyze discharged glass to determine sulfur retention in the glass. ? Prepare and characterize feeds and glasses with the additives to confirm that the feeds and the glass melts are suitable for processing in the DM100 melter. ? Prepare and characterize glasses with the additives to confirm that the glasses meet the waste form (ILAW) performance requirements.

  9. Oxygen vacancy migration in disordered Gd{sub 2}(Zr{sub x}Ti{sub 1{minus}x}){sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Williford, R.E.; Weber, W.J.; Devanathan, R.; Gale, J.D.

    1999-07-01

    Oxygen vacancy formation and migration energies in the pyrochlores Gd{sub 2}(Zr{sub x}Ti{sub 1{minus}x}){sub 2}O{sub 7} were computed using atomistic energy minimization methods, with particular attention to the role of cation antisite disorder. The interatomic potentials recognize oxygens in distinct crystallographic sites (polarizations) as distinct species, and permit assessment of the directional anisotropy in vacancy migration energies. Oxygen vacancy migration is determined by O{sub 48f} {minus} O{sub 48f} transitions along the shortest edges of the TiO{sub 6} octahedra, in agreement with previous results. Oxygen vacancies migrate towards disorder to reduce local stresses. In contrast to previous work, the V{sub 08a} and V{sub O8a} + I{sub O8b} Frenkel defects are favored over the V{sub O48f} and V{sub O48f} + I{sub O8b} Frenkel. The transition V{sub O8a}{minus}> V{sub O48f} is energetically favored for the ordered structure, and activates the three dimensional O{sub 48f} {minus} O{sub 48f} vacancy migration network by filling empty 9a sites with 48f oxygens. Local regions of order and moderate disorder must both be present for optimum oxygen conductivity. High disorder retards vacancy migration.

  10. High temperature redox reactions with uranium: Synthesis and characterization of Cs(UO{sub 2})Cl(SeO{sub 3}), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 2}, and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7}

    SciTech Connect (OSTI)

    Babo, Jean-Marie; Albrecht-Schmitt, Thomas E.

    2013-10-15

    Cs(UO{sub 2})Cl(SeO{sub 3}) (1), Rb{sub 2}(UO{sub 2}){sub 3}O{sub 2}(SeO{sub 3}){sub 3} (2), and RbNa{sub 5}U{sub 2}(SO{sub 4}){sub 7} (3) single crystals were synthesized using CsCl, RbCl, and a CuCl/NaCl eutectic mixture as fluxes, respectively. Their lattice parameters and space groups are as follows: P2{sub 1}/n (a=6.548(1) Å, b=11.052(2) Å, c=10.666(2) Å and β=93.897(3)°), P1{sup ¯} (a=7.051(2) Å, b=7.198(2) Å, c=8.314(2) Å, α=107.897(3)°, β=102.687(3)° and γ=100.564(3)°) and C2/c (a=17.862(4) Å, b=6.931(1) Å, c=20.133(4) Å and β=109.737(6)°. The small anionic building units found in these compounds are SeO{sub 3}{sup 2−} and SO{sub 4}{sup 2−} tetrahedra, oxide, and chloride. The crystal structure of the first compound is composed of [(UO{sub 2}){sub 2}Cl{sub 2}(SeO{sub 3}){sub 2}]{sup 2−} chains separated by Cs{sup +} cations. The structure of (2) is constructed from [(UO{sub 2}){sub 3}O{sub 11}]{sup 16−} chains further connected through selenite units into layers stacked perpendicularly to the [0 1 0] direction, with Rb{sup +} cations intercalating between them. The structure of compound (3) is made of uranyl sulfate layers formed by edge and vertex connections between dimeric [U{sub 2}O{sub 16}] and [SO{sub 4}] polyhedra. These layers contain unusual sulfate–metal connectivity as well as large voids. - Graphical abstract: A new family of uranyl selenites and sulfates has been prepared by high-temperature redox reactions. This compounds display new bonding motifs. Display Omitted - Highlights: • Low-dimensional Uranyl Oxoanion compounds. • Conversion of U(IV) to U(VI) at high temperatures. • Dimensional reduction by both halides and stereochemically active lone-pairs.

  11. Complex conductance of ultrathin La<sub>2-xsub>SrxCuO>4sub> films and heterostructures

    SciTech Connect (OSTI)

    V. A. Gasparov; Bozovic, I.

    2015-10-23

    We used atomic-layer molecular beam epitaxy to synthesize bilayers of a cuprate metal (La<sub>1.55sub>Sr>0.45sub>CuO>4sub>) and a cuprate insulator (La<sub>2sub>CuO>4sub>), in which each layer is just one unit cells thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films. Experiments have been carried out at frequencies between 2 and 50 MHz using the single-spiral coil technique. We found that: (i) the inductive response starts at ΔT = 3 K lower temperatures than Re σ(T), which in turn is characterized by a peak close to the transition, (ii) this shift is almost constant with magnetic field up to 14 mT; (iii) ΔT increases sharply up to 4 K at larger fields and becomes constant up to 8 T; (iv) the vortexdiffusion constant D(T) is not linear with T at low temperatures as in the case of free vortices, but is rather exponential due to pinning of vortex cores, and (v) the dynamic Berezinski–Kosterlitz–Thouless (BKT) transition temperature occurs at the point where Y=(l<sub>ω>/ξ+)2 = 1. As a result, our experimental results can be described well by the extended dynamic theory of the BKT transition and dynamics of bound vortex–antivortex pairs with short separation lengths.

  12. Anionic ordering and thermal properties of FeF<sub>3sub>·3H<sub>2sub>O

    SciTech Connect (OSTI)

    Burbano, Mario; Duttine, Mathieu; Borkiewicz, Olaf; Wattiaux, Alain; Demourgues, Alain; Salanne, Mathieu; Groult, Henri; Dambournet, Damien

    2015-09-17

    In this study, iron fluoride tri-hydrate can be used to prepare iron hydroxyfluoride with the Hexagonal-Tungsten-Bronze (HTB) type structure, a potential cathode material for batteries. To understand this phase transformation, a structural description of β-FeF<sub>3sub>·3H<sub>2sub>O is first performed by means of DFT calculations and Mössbauer spectroscopy. The structure of this compound consists of infinite chains of [FeF<sub>6sub>]n and [FeF<sub>2sub>(H2O)<sub>4sub>]n>. The decomposition of FeF<sub>3sub>·3H<sub>2sub>O induces a collapse and condensation of these chains, which lead to the stabilization, under specific conditions, of a hydroxyfluoride network FeF<sub>3-xsub>(OH)x> with the HTB structure. The release of H<sub>2sub>O and HF was monitored by thermal analysis and physical characterizations during the decomposition of FeF<sub>3sub>·3H<sub>2sub>O. An average distribution of FeF<sub>4sub>(OH)>2sub> distorted octahedra in HTB-FeF<sub>3-xsub>(OH)x> was obtained subsequent to the thermal hydrolysis/olation of equatorial anionic positions involving F- and H<sub>2sub>O. This study provides a clear understanding of the structure and thermal properties of FeF<sub>3sub>·3H<sub>2sub>O, a material that can potentially bridge the recycling of pickling sludge from the steel industry by preparing battery electrodes.

  13. Neutron-scattering evidence for a periodically modulated superconducting phase in the underdoped cuprate La<sub>1.905sub>Ba>0.095sub>CuO>4sub>

    SciTech Connect (OSTI)

    Xu, Zhijun; Stock, C.; Chi, Songxue; Kolesnikov, A. I.; Xu, Guangyong I.; Gu, Genda; Tranquada, J. M.

    2014-10-01

    The role of antiferromagnetic spin correlations in high-temperature superconductors remains a matter of debate. We present inelastic neutron-scattering evidence that gapless spin fluctuations coexist with superconductivity in La<sub>1.905sub>Ba>0.095sub>CuO>4sub>. Furthermore, we observe that both the low-energy magnetic spectral weight and the spin incommensurability are enhanced with the onset of superconducting correlations. We propose that the coexistence occurs through intertwining of spatial modulations of the pair wave function and the antiferromagnetic correlations. This proposal is also directly relevant to sufficiently underdoped La<sub>2-xsub>SrxCuO>4sub> and YBa<sub>2sub>Cu>3sub>O>6+xsub>.

  14. Covariance mapping of two-photon double core hole states in C <sub>2sub> H <sub>2sub> and C <sub>2sub> H <sub>6sub> produced by an x-ray free electron laser

    SciTech Connect (OSTI)

    Mucke, M; Zhaunerchyk, V; Frasinski, L J; Squibb, R J; Siano, M; Eland, J H D; Linusson, P; Salén, P; Meulen, P v d; Thomas, R D; Larsson, M; Foucar, L; Ullrich, J; Motomura, K; Mondal, S; Ueda, K; Osipov, T; Fang, L; Murphy, B F; Berrah, N; Bostedt, C; Bozek, J D; Schorb, S; Messerschmidt, M; Glownia, J M; Cryan, J P; Coffee, R N; Takahashi, O; Wada, S; Piancastelli, M N; Richter, R; Prince, K C; Feifel, R

    2015-07-01

    Few-photon ionization and relaxation processes in acetylene (C<sub>2sub>H>2sub>) and ethane (C<sub>2sub>H>6sub>) were investigated at the linac coherent light source x-ray free electron laser (FEL) at SLAC, Stanford using a highly efficient multi-particle correlation spectroscopy technique based on a magnetic bottle. The analysis method of covariance mapping has been applied and enhanced, allowing us to identify electron pairs associated with double core hole (DCH) production and competing multiple ionization processes including Auger decay sequences. The experimental technique and the analysis procedure are discussed in the light of earlier investigations of DCH studies carried out at the same FEL and at third generation synchrotron radiation sources. In particular, we demonstrate the capability of the covariance mapping technique to disentangle the formation of molecular DCH states which is barely feasible with conventional electron spectroscopy methods.

  15. Luminescence of Ce 3+ -Doped MB<sub>2sub>Si>2sub>O>8sub> (M = Sr, Ba): A Deeper Insight into the Effects of Electronic Structure and Stokes Shift

    SciTech Connect (OSTI)

    Peng, Qi; Liu, Chunmeng; Hou, Dejian; Zhou, Weijie; Ma, Chong-Geng; Liu, Guokui; Brik, Mikhail G.; Tao, Ye; Liang, Hongbin

    2015-12-18

    A series of Sr <sub>1 -2x sub>Ce<sub>xNaxB>2sub>Si>2sub>O>8sub> and Ba <sub>1-2x sub>Ce<sub>xKxB>2sub>Si>2sub>O>8sub> (x = 0.005, 0.01, 0.02, 0.04, 0.06, 0.08) samples were synthesized by a high-temperature solid-state reaction. The low temperature excitation, emission, and fluorescence decay spectra together demonstrated that all spectral bands arise from the Ce 3+ ions located at only one kind of lattice site. The first-principles calculations of the structural and electronic properties of pure and Ce 3+sub>2sub>Si>2sub>O>8sub> (M = Sr, Ba) were performed, and the obtained results were used for understanding the structural changes after doping and identification of the observed position of the host absorption bands. The measured 4f-5d excitation and emission spectra of Ce3+ ions doped in MB<sub>2sub>Si>2sub>O>8sub> were analyzed and simulated in the framework of the crystal-field (CF) theory. The electron-phonon coupling effect generally ignored in most studies published so far was also taken into account by applying the configurational coordinate model. The validity of such a combined insight into the 5d CF energy level positions and the Stokes shift has been confirmed by analyzing the dependence of the Ce 3+

  16. Reverse Monte Carlo simulation of Se{sub 80}Te{sub 20} and Se{sub 80}Te{sub 15}Sb{sub 5} glasses

    SciTech Connect (OSTI)

    Abdel-Baset, A. M.; Rashad, M.; Moharram, A. H.

    2013-12-16

    Two-dimensional Monte Carlo of the total pair distribution functions g(r) is determined for Se{sub 80}Te{sub 20} and Se{sub 80}Te{sub 15}Sb{sub 5} alloys, and then it used to assemble the three-dimensional atomic configurations using the reverse Monte Carlo simulation. The partial pair distribution functions g{sub ij}(r) indicate that the basic structure unit in the Se{sub 80}Te{sub 15}Sb{sub 5} glass is di-antimony tri-selenide units connected together through Se-Se and Se-Te chain. The structure of Se{sub 80}Te{sub 20} alloys is a chain of Se-Te and Se-Se in addition to some rings of Se atoms.

  17. Lasing characteristics of ZrO{sub 2}Y{sub 2}O{sub 3}Ho{sub 2}O{sub 3} crystal

    SciTech Connect (OSTI)

    Borik, M A; Lomonova, E E; Kulebyakin, A V; Ushakov, S N; Lyapin, A A; Ryabochkina, P A; Chabushkin, A N

    2013-09-30

    The spectral dependences of the gain cross section of the {sup 5}I{sub 8} ? {sup 5}I{sub 7}, {sup 5}I{sub 7} ? {sup 5}I{sub 8} transition of Ho{sup 3+} ions in the ZrO{sub 2} 13.6 mol % Y{sub 2}O{sub 3} 0.4 mol % Ho{sub 2}O{sub 3} crystal are calculated at different relative population inversions using the absorption and luminescence spectra of the {sup 5}I{sub 8} ? {sup 5}I{sub 7} and {sup 5}I{sub 7} ? {sup 5}I{sub 8} transitions of Ho{sup 3+} ions at T=''300'' K. Lasing of these crystals at the {sup 5}I{sub 7} ? {sup 5}I{sub 8} transition is obtained for the first time under pumping by a Tm : YLiF{sub 4} laser (?{sub p} = 1.905 ?m). The lasing wavelength is 2.17 ?m. (lasers)

  18. Synthesis of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction with enhanced photocatalytic performance

    SciTech Connect (OSTI)

    He, Peizhi; Song, Limin; Zhang, Shujuan; Wu, Xiaoqing; Wei, Qingwu

    2014-03-01

    Graphical abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The results show that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} possesses a much higher activity for the decomposition of RhB than that of the pure Ag{sub 3}PO{sub 4} particles. The most mechanism is that g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst can efficiently separate the photogenerated electronhole pairs, enhancing the photocatalytic activity of g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} composites. - Highlights: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction showed much higher activity than that of Ag{sub 3}PO{sub 4}. The high activity could be attributed to g-C{sub 3}N{sub 4} for modifying Ag{sub 3}PO{sub 4}. More OH radicals may be significant reason to improve Ag{sub 3}PO{sub 4} activity. - Abstract: g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst with visible-light response was prepared by a facile coprecipitation method. The photocatalysts were characterized by X-ray powder diffraction, transmission electron microscopy, UVvis absorption spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic activities of the obtained samples were tested by using Rhodamine B (RhB) as the degradation target under visible light irradiation. g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} decomposed RhB more effectively than the pure Ag{sub 3}PO{sub 4} particles did, and 2 wt.% g-C{sub 3}N{sub 4} had the highest activity. Furthermore, 2 wt.% g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} degraded high-concentration RhB more potently than unmodified Ag{sub 3}PO{sub 4} did, probably because g-C{sub 3}N{sub 4}/Ag{sub 3}PO{sub 4} heterojunction photocatalyst enhanced the photocatalytic activity by efficiently separating the photogenerated electronhole pairs.

  19. [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}], crystal structure and comparison with uranium minerals with U{sub 3}O{sub 8}-type sheets

    SciTech Connect (OSTI)

    Rivenet, Murielle; Vigier, Nicolas; Roussel, Pascal; Abraham, Francis

    2009-04-15

    The new U(VI) compound, [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}], was synthesized by mild hydrothermal reaction of uranyl and nickel nitrates. The crystal-structure was solved in the P-1 space group, a=8.627(2), b=10.566(2), c=12.091(4) A and alpha=110.59(1), beta=102.96(2), gamma=105.50(1){sup o}, R=0.0539 and wR=0.0464 from 3441 unique observed reflections and 151 parameters. The structure of the title compound is built from sheets of uranium polyhedra closely related to that in beta-U{sub 3}O{sub 8}. Within the sheets [(UO{sub 2})(OH)O{sub 4}] pentagonal bipyramids share equatorial edges to form chains, which are cross-linked by [(UO{sub 2})O{sub 4}] and [UO{sub 4}(H{sub 2}O)(OH)] square bipyramids and through hydroxyl groups shared between [(UO{sub 2})(OH)O{sub 4}] pentagonal bipyramids. The sheets are pillared by sharing the apical oxygen atoms of the [(UO{sub 2})(OH)O{sub 4}] pentagonal bipyramids with the oxygen atoms of [NiO{sub 2}(H{sub 2}O){sub 4}] octahedral units. That builds a three-dimensional framework with water molecules pointing towards the channels. On heating [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}] decomposes into NiU{sub 3}O{sub 10}. - Graphical abstract: The framework of [Ni(H{sub 2}O){sub 4}]{sub 3}[U(OH,H{sub 2}O)(UO{sub 2}){sub 8}O{sub 12}(OH){sub 3}] built from uranium polyhedra sheets pillared by Ni-centered octahedra.

  20. Magnetism and superconductivity in U?Pt<sub>xRh>(1x)sub>C?

    SciTech Connect (OSTI)

    Wakeham, N.; Ni, Ni; Bauer, E. D.; Thompson, J. D.; Tegtmeier, E.; Ronning, F.

    2015-01-01

    We report the phase diagram of the doping series U?Pt<sub>xRh>(1x)sub>C?, studied through measurements of resistivity, specific heat, and magnetic susceptibility. The Nel temperature of U?Rh?C? of ~ 22 K is suppressed with increasing Pt content, reaching zero temperature close to x = 0.7, where we observed signatures of increased quantum fluctuations. In addition, evidence is presented that the antiferromagnetic state undergoes a spin-reorientation transition upon application of an applied magnetic field. This transition shows non-monotonic behavior as a function of x, peaking at around x = 0.3. Superconductivity is observed for x ? 0.9, with T<sub>c> increasing with increasing x. The reduction in T<sub>c> and increase in residual resistivity with decreasing Pt content is inconsistent with the extension of the Abrikosov-Gor'kov theory to unconventional superconductivity.

  1. Criticality Safety Study of UF<sub>6sub>and UO<sub>2sub>F>2sub>in 8-in. Inner Diameter Piping

    SciTech Connect (OSTI)

    Elam, K.R.

    2003-10-07

    The purpose of this report is to provide an evaluation of the criticality safety aspects of using up to 8-in.-inner-diameter (ID) piping as part of a system to monitor the {sup 235}U enrichment in uranium hexafluoride (UF{sub 6}) gas both before and after an enrichment down-blending operation. The evaluated operation does not include the blending stage but includes only the monitors and the piping directly associated with the monitors, which are in a separate room from the blending operation. There are active controls in place to limit the enrichment of the blended UF{sub 6} to a maximum of 5 weight percent (wt%) {sup 235}U. Under normal operating conditions of temperature and pressure, the UF{sub 6} will stay in the gas phase and criticality will not be credible. The two accidents of concern are solidification of the UF{sub 6} along with some hydrofluoric acid (HF) and water or moisture ingress, which would cause the UF{sub 6} gas to react and form a hydrated uranyl fluoride (UO{sub 2}F{sub 2}) solid or solution. Of these two types of accidents, the addition of water and formation of UO{sub 2}F{sub 2} is the most reactive scenario and thus limits related to UO{sub 2}F{sub 2} will bound the limits related to UF{sub 6}. Two types of systems are included in the monitoring process. The first measures the enrichment of the approximately 90 wt% enriched UF{sub 6} before it is blended. This system uses a maximum 4-in.-(10.16-cm-) ID pipe, which is smaller than the 13.7-cm-cylinder-diameter subcritical limit for UO{sub 2}F{sub 2} solution of any enrichment as given in Table 1 of American National Standard ANSI/ANS-8.1.1 Therefore, this system poses no criticality concerns for either accident scenario. The second type of system includes two enrichment monitors for lower-enriched UF{sub 6}. One monitors the approximately 1.5 wt% enriched UF{sub 6} entering the blending process, and the second monitors the approximately 5 wt% enriched UF{sub 6} coming out of the blending process. Both use a maximum 8-in.-(20.32-cm-) ID piping, where the length of the larger ID piping is approximately 9.5 m. This diameter of piping is below the 26.6-cm-cylinder-diameter subcritical limit for 5 wt% enriched UO{sub 2}F{sub 2} solutions as given in Table 6 of ANSI/ANS-8.1. Therefore, for up to 5 wt% enriched UF{sub 6}, this piping does not present a criticality concern for either accident scenario. Calculations were performed to determine the enrichment level at which criticality could become a concern in these 8-in.-ID piping sections. Both unreflected and fully water-reflected conditions were considered.

  2. Properties of Si{sub n}, Ge{sub n}, and Si{sub n}Ge{sub n} clusters

    SciTech Connect (OSTI)

    Dong, Yi; Rehman, Habib ur; Springborg, Michael

    2015-01-22

    The structures of Si{sub n}, Ge{sub n}, and Si{sub n}Ge{sub n} clusters with up to 44 atoms have been determined theoretically using an unbiased structure-optimization method in combination with a parametrized, density-functional description of the total energy for a given structure. By analyzing the total energy in detail, particularly stable clusters are identified. Moreover, general trends in the structures are identified with the help of specifically constructed descriptors.

  3. Correlating Local Structure with Electrochemical Activity in L<sub>i2sub>MnO>3sub>

    SciTech Connect (OSTI)

    Nanda, Jagjit; Sacci, Robert L.; Veith, Gabriel M.; Dixit, Hemant M.; Cooper, Valentino R.; Pezeshki, Alan M.; Ruther, Rose E.

    2015-07-31

    Li<sub>2sub>MnO>3sub> is of interest as one component of the composite lithium-rich oxides, which are under development for high capacity, high voltage cathodes in lithium ion batteries. Despite such practical importance, the mechanism of electrochemical activity in Li<sub>2sub>MnO>3sub> is contested in the literature, as are the effects of long-term electrochemical cycling. Here, Raman spectroscopy and mapping are used to follow the chemical and structural changes that occur in Li<sub>2sub>MnO>3sub>. Both conventional slurry electrodes and thin films are studied as a function of the state of charge (voltage) and cycle number. Thin films have similar electrochemical properties as electrodes prepared from slurries, but allow for spectroscopic investigations on uniform samples without carbon additives. Spectral changes correlate well with electrochemical activity and support a mechanism whereby capacity is lost upon extended cycling due to the formation of new manganese oxide phases. Raman mapping of both thin film and slurry electrodes charged to different voltages reveals significant variation in the local structure. Poor conductivity and slow kinetics associated with a two-phase reaction mechanism contribute to the heterogeneity.

  4. High-G testing of MEMS mechanical non-volatile memory and silicon...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: High-G testing of MEMS mechanical non-volatile memory and silicon re-entry switch. Citation Details In-Document Search Title: High-G testing of MEMS mechanical ...

  5. Method and apparatus for regenerating activated carbon containing an adsorbed volatile organic absorbate

    SciTech Connect (OSTI)

    Tiggelbeck, D.D.; Goyak, G.M.

    1993-07-27

    A method is described for regenerating spent activated carbon containing adsorbed volatile organic adsorbate comprising: establishing a confined downwardly moving bed of activated carbon; adding spent carbon to the top of said bed; introducing superheated steam into the bottom of said bed in contact with said carbon; recovering exit gas including predominantly superheated steam and volatilized adsorbate from the top of said bed; circulating a portion of said exit gas through a superheater and compressor to the bottom of said bed; withdrawing a portion of said exit gas through a cooler to condense steam and volatile adsorbate; continuously circulating superheated steam in a closed loop through said downwardly moving bed, said compressor and said superheater; recovering partially regenerated activated carbon containing residual volatile adsorbate from the bottom of said bed.

  6. Volatilization of selected organic compounds from a creosote-waste land-treatment facility. Master's thesis

    SciTech Connect (OSTI)

    Scott, E.J.

    1989-01-01

    The purpose of this research was to evaluate the emissions of volatile and semi-volatile compounds which are constituents of a complex creosote waste from laboratory simulations of a land treatment system to assess the potential human exposure to hazardous compounds from this source. In addition, the Thibodeaux-Hwang Air Emission Release Rate (AERR) model was evaluated for its use in predicting emission rates of hazardous constituents of creosote wood preservative waste from land treatment facilities. A group of hazardous volatile and semi-volatile constituents present in the creosote waste was selected for evaluation in this study and included a variety of polynuclear aromatic hydrocarbons (PNA's), phenol, and chlorinated and substituted phenols.

  7. Photoelectrocatalytic study of water oxidation at n-RuS{sub 2} electrodes

    SciTech Connect (OSTI)

    Salvador, P.; Alonso-Vante, N.; Tributsch, H.

    1998-01-01

    A kinetic study of the photocatalytic oxidation of water at a n-RuS{sub 2} semiconducting single crystal has been undertaken on the basis of photocurrent transients (photocurrent-time behavior as a function of the polarization potential, illumination intensity, and temperature) and electrolyte electroreflectance experiments. The main factor defining the catalytic activity of RuS{sub 2} for water oxidation, both in the dark and under illumination, is a low overpotential ({eta} {approx} 0.3 V), which is comparable to that of the RuO{sub 2} catalyst for oxygen evolution at darkness. Evidence has been given that {eta} is determined by the E{sup o}(Ru{sub s}-OH{sup 0}/Ru{sub s}-H{sub 2}O) redox potential, which strongly depends on the bonding energy of Ru surface species with OH{sup o} radicals generated by direct oxidation of adsorbed water molecules (interfacial Ru-peroxo-type complex formation). This bonding energy increases as the RuS{sub 2} surface becomes oxidized under anodic polarization and reaches its maximum value at the potential of the S{sub 2}RuO{sub 2}/RuS{sub 2} transition (VIII Ru oxidation state). Further oxidation of the Ru-peroxo-type complexes leads to oxygen evolution at a rate which increases with the degree of oxidation of the Ru surface active centers. Although O{sub 2} evolution probably already takes place on Ru(VI) surface sites, high evolution rates (current densities) are only reached under oxidation state VIII. However, in this state (idealized S{sub 2}Ru(VIII)O{sub 2}) Ru-S surface bonds are weakened and occasionally broken, contributing to RuS{sub 2} dissolution with generation of volatile RuO{sub 4} and SO{sub 4}{sup 2{minus}} soluble ions as the main corrosion products. This phenomenon may be attributed to the reaction in acidic medium of H{sub 2}O molecules with Ru(VIII) surface species, giving rise to the formation of unstable intermediate complexes.

  8. Influence of valence electron concentration on Laves phases: Structures and phase stability of pseudo-binary MgZn<sub>2-xsub>Pdx>

    SciTech Connect (OSTI)

    Thimmaiah, Srinivasa; Miller, Gordon J.

    2015-06-03

    A series of pseudo-binary compounds MgZn<sub>2-xsub>Pdx> (0.15 ? x ? 1.0) were synthesized and structurally characterized to understand the role of valence electron concentration (vec) on the prototype Laves phase MgZn<sub>2sub> with Pd-substitution. Three distinctive phase regions were observed with respect to Pd content, all exhibiting fundamental Laves phase structures: 0.1 ? x ? 0.3 (MgNi<sub>2sub>-type, hP24; MgZn<sub>1.80sub>Pd>0.20(2)sub>), 0.4 ? x ? 0.6 (MgCu<sub>2sub>-type, cF24; MgZn<sub>1.59sub>Pd>0.41(2)sub>), and 0.62 ? x ? 0.8 (MgZn<sub>2sub>-type, hP12: MgZn<sub>1.37sub>Pd>0.63(2)sub>). Refinements from single-crystal X-ray diffraction indicated nearly statistical distributions of Pd and Zn atoms among the majority atom sites in these structures. Interestingly, the MgZn<sub>2sub>-type structure re-emerges in MgZn<sub>2xsub>Pdx> at x ? 0.7 with the refined composition MgZn<sub>1.37(2)sub>Pd>0.63sub> and a c/a ratio of 1.59 compared to 1.64 for binary MgZn<sub>2sub>. Electronic structure calculations on a model MgZn<sub>1.25sub>Pd>0.75sub> yielded a density of states (DOS) curve showing enhancement of a pseudogap at the Fermi level as a result of electronic stabilization due to the Pd addition. Moreover, integrated crystal orbital Hamilton population values show significant increases of orbital interactions for (Zn,Pd)(Zn,Pd) atom pairs within the majority atom substructure, i.e., within the Kagom nets as well as between a Kagom net and an apical site, from binary MgZn<sub>2sub> to the ternary MgZn<sub>1.25sub>Pd>0.75sub>. Multi-centered bonding is evident from electron localization function plots for MgZn<sub>1.25sub>Pd>0.75sub>, an outcome which is in accordance with analysis of other Laves phases.

  9. FDATMOS16 non-linear partitioning and organic volatility distributions in

    Office of Scientific and Technical Information (OSTI)

    urban aerosols (Journal Article) | SciTech Connect FDATMOS16 non-linear partitioning and organic volatility distributions in urban aerosols Citation Details In-Document Search This content will become publicly available on December 17, 2016 Title: FDATMOS16 non-linear partitioning and organic volatility distributions in urban aerosols Gas-to-particle partitioning of organic aerosols (OA) is represented in most models by Raoult's law, and depends on the existing mass of particles into which

  10. Green Ocean Amazon (GoAmazon) 2014/15. Semi-Volatile Thermal Desorption

    Office of Scientific and Technical Information (OSTI)

    Aerosol Gas Chromatograph (SVTAG) Field Campaign Report (Technical Report) | SciTech Connect Green Ocean Amazon (GoAmazon) 2014/15. Semi-Volatile Thermal Desorption Aerosol Gas Chromatograph (SVTAG) Field Campaign Report Citation Details In-Document Search Title: Green Ocean Amazon (GoAmazon) 2014/15. Semi-Volatile Thermal Desorption Aerosol Gas Chromatograph (SVTAG) Field Campaign Report In areas where biogenic emissions are oxidized in the presence of anthropogenic pollutants such as SO2,

  11. Ecosystem-scale volatile organic compound fluxes during an extreme drought

    Office of Scientific and Technical Information (OSTI)

    in a broadleaf temperate forest of the Missouri Ozarks (central USA) (Journal Article) | SciTech Connect This content will become publicly available on July 7, 2016 Title: Ecosystem-scale volatile organic compound fluxes during an extreme drought in a broadleaf temperate forest of the Missouri Ozarks (central USA) Considerable amounts and varieties of biogenic volatile organic compounds (BVOCs) are exchanged between vegetation and the surrounding air. These BVOCs play key ecological and

  12. Synthesis, crystal structure and thermal behavior of two hydrated forms of lanthanide phthalates Ln{sub 2}(O{sub 2}+C{sub 6}H{sub 4}-CO{sub 2}){sub 3}(H{sub 2}O) (Ln=Ce, Nd) and Nd{sub 2}(O{sub 2}C-C{sub 6}H{sub 4}-CO{sub 2}){sub 3}(H{sub 2}O){sub 3}

    SciTech Connect (OSTI)

    Pizon, David; Henry, Natacha; Loiseau, Thierry; Roussel, Pascal; Abraham, Francis

    2010-09-15

    New hydrated lanthanide phthalates have been hydrothermally prepared with cerium and neodymium in different reaction media involving water or mixed water-ethanol solvent. The monohydrated Ln{sub 2}(1,2-bdc){sub 3}(H{sub 2}O) (Ln=Ce or Nd) and dihydrated Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub 2} forms have been characterized by single-crystal analysis. Their structures consist of infinite inorganic chains of lanthanide-centered polyhedra linked to each other through the phthalate ligands in order to generate mixed organic-inorganic layered structure. The two hydrated structures differ by the number of terminal water species attached to the lanthanide cations, which induce symmetry change from a triclinic (Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub 2}) to an orthorhombic (Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub 2}) cell for neodymium whereas the cerium-based phase only exists in the monohydrated form, with two distinct symmetries (orthorhombic or triclinic). Structural comparisons with the other members of the lanthanide phthalate series with identical chemical formula are also discussed. Thermal X-ray diffraction experiment indicates that the transformation from dihydrate form into the monohydrated form does not occur during a heating process. - Graphical abstract: New members of the chain-like structures of neodymium phthalates with different hydration states Nd{sub 2}(1,2-bdc){sub 3}(H{sub 2}O){sub x} (x=1 or 2, 1-2bdc=phthalate group) and comparison with cerium-based analogs.

  13. Oxygen trapped by rare earth tetrahedral clusters in Nd<sub>4sub>FeOS>6sub>: Crystal structure, electronic structure, and magnetic properties

    SciTech Connect (OSTI)

    Lin, Qisheng; Taufour, Valentin; Zhang, Yuemei; Wood, Max; Drtina, Thomas; Bud’ko, Sergey L.; Canfield, Paul C.; Miller, Gordon J.

    2015-05-22

    Single crystals of Nd<sub>4sub>FeOS>6sub> were grown from an Fe-S eutectic solution. Single crystal X-ray diffraction analysis revealed a Nd<sub>4sub>MnOSe>6sub>-type structure (P6<sub>3sub>mc, a = 9.2693(1) Å, c = 6.6650(1) Å, V = 495.94(1) Å3, Z = 2), featuring parallel chains of face-sharing [FeS<sub>6x1/2sub>]4- trigonal antiprisms and interlinked [Nd<sub>4sub>OS>3sub>]4+ cubane-like clusters. Oxygen atoms were found to be trapped by Nd4 clusters in the [Nd4OS3]4+ chains. Structural differences among Nd<sub>4sub>MnOSe>6sub>-type Nd<sub>4sub>FeOS>6sub> and the related La<sub>3sub>CuSiS>7sub>- and Pr<sub>8sub>CoGa>3sub>-type structures have been described. Magnetic susceptibility measurements on Nd<sub>4sub>FeOS>6sub> suggested the dominance of antiferromagnetic interactions at low temperature, but no magnetic ordering down to 2 K was observed. Spin-polarized electronic structure calculations revealed magnetic frustration with dominant antiferromagnetic interactions.

  14. Structureproperty relations of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O

    SciTech Connect (OSTI)

    Hausshl, Eiken; Schreuer, Jrgen; Wiehl, Leonore; Paulsen, Natalia

    2014-04-01

    Large single crystals of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O with dimensions up to 404030 mm{sup 3} were grown from aqueous solutions. The elastic and piezoelastic coefficients were derived from ultrasonic resonance frequencies and their shifts upon variation of pressure, respectively, using the plate-resonance technique. Additionally, the coefficients of thermal expansion were determined between 95 K and 305 K by dilatometry. The elastic behaviour at ambient conditions is dominated by the 2-dimensional network of strong hydrogen bonds within the (001) plane leading to a corresponding pseudo-tetragonal anisotropy of the longitudinal elastic stiffness. The variation of elastic properties with pressure, however, as well as the thermal expansion shows strong deviations from the pseudo-tetragonal symmetry. These deviations are probably correlated with tilts of the elongated tri-nuclear betaineCuCl{sub 2}water complexes. Neither the thermal expansion nor the specific heat capacity gives any hint on a phase transition in the investigated temperature range. - Graphical abstract: Single crystal of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O. - Highlights: Large single crystals (40 40 30 mm{sup 3}) of [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}2H{sub 2}O were grown. The elastic and piezoelastic coefficients were derived from ultrasonic resonance frequencies. Thermal expansion (95 K305 K) and heat capacity (113 K323 K) were determined. The orthorhombic structure shows pseudo-tetragonal elastic anisotropy at ambient conditions. The crystal structure is stable in the investigated range (11600 bar, 95303 K)

  15. Estimation of stochastic volatility with long memory for index prices of FTSE Bursa Malaysia KLCI

    SciTech Connect (OSTI)

    Chen, Kho Chia; Kane, Ibrahim Lawal; Rahman, Haliza Abd; Bahar, Arifah; Ting, Chee-Ming

    2015-02-03

    In recent years, modeling in long memory properties or fractionally integrated processes in stochastic volatility has been applied in the financial time series. A time series with structural breaks can generate a strong persistence in the autocorrelation function, which is an observed behaviour of a long memory process. This paper considers the structural break of data in order to determine true long memory time series data. Unlike usual short memory models for log volatility, the fractional Ornstein-Uhlenbeck process is neither a Markovian process nor can it be easily transformed into a Markovian process. This makes the likelihood evaluation and parameter estimation for the long memory stochastic volatility (LMSV) model challenging tasks. The drift and volatility parameters of the fractional Ornstein-Unlenbeck model are estimated separately using the least square estimator (lse) and quadratic generalized variations (qgv) method respectively. Finally, the empirical distribution of unobserved volatility is estimated using the particle filtering with sequential important sampling-resampling (SIR) method. The mean square error (MSE) between the estimated and empirical volatility indicates that the performance of the model towards the index prices of FTSE Bursa Malaysia KLCI is fairly well.

  16. Bio-corrosion and cytotoxicity studies on novel Zr<sub>55sub>Co>30sub>Ti>15sub> and Cu<sub>60sub>Zr>20sub>Ti>20sub> metallic glasses

    SciTech Connect (OSTI)

    Vincent, S.; Daiwile, A.; Devi, S. S.; Kramer, M. J.; Besser, M. F.; Murty, B. S.; Bhatt, Jatin

    2014-09-26

    Metallic glasses are a potential and compatible implant candidate for biomedical applications. In the present investigation, a comparative study between novel Zr<sub>55sub>Co>30sub>Ti>15sub> and Cu<sub>60sub>Zr>20sub>Ti>20sub> metallic glasses is carried out to evaluate in vitro biocompatibility using simulated body fluids. The bio-corrosion behavior of Zr- and Cu-based metallic glasses in different types of artificial body fluids such as artificial saliva solution, phosphate-buffered saline solution, artificial blood plasma solution, and Hanks balanced saline solution is evaluated using potentiodynamic polarization studies at a constant body temperature of 310.15 K (37 C). Surface morphology of samples after bio-corrosion experiments was observed by scanning electron microscopy. In vitro cytotoxicity test on glassy alloys were performed using human osteosarcoma cell line as per 10993-5 guidelines from International Organization for Standardization. As a result, the comparative study between Zr- and Cu-based glassy alloys provides vital information about the effect of elemental composition on biocompatibility of metallic glasses.

  17. Dimethyl sulfide substituted mixed-metal clusters: Synthesis, structure, and characterization of HRuCo sub 3 (CO) sub 11 (SMe sub 2 ) and (HRuRh sub 3 (CO) sub 9 ) sub 2 (SMe sub 2 ) sub 3

    SciTech Connect (OSTI)

    Rossi, S.; Pursianinen, J.; Ahlgren, M.; Pakkanen, T.A. (Univ. of Joensuu (Finland))

    1990-02-01

    Ligand substitution reactions of dimethyl sulfide with mixed-metal clusters are described. The clusters HRuCo{sub 3}(CO){sub 11}(SMe{sub 2}) (1) and (HRuRh{sub 3}(CO){sub 9}){sub 2}(SMe{sub 2}){sub 3} (2) have been prepared by reactions of SMe{sub 2} with the neutral parent clusters. Their crystal structures have been established: 1, monoclinic, space group P2{sub 1}/n, a = 11.459 (5) {angstrom}, b = 12.484 (4) {angstrom}, c = 14.384 (4) {angstrom}, {beta} = 96.40 (3){degree}, Z = 4; 2, trigonal, space group R3c, a = 13.181 (7) {angstrom}, {alpha} = 75.54 (5){degree}, Z = 2. Dimethyl sulfide coordinates terminally as a two-electron donor on basal cobalt in 1 and as a bridging four-electron donor causing unusual dimerization of clusters in 2. The carbonyl arrangement of the parent clusters was not changed during the ligand substitution, and hydride ligands bridge the three basal metals in both compounds.

  18. Quantum critical fluctuations in the heavy fermion compound Ce(Ni<sub>0.935sub> Pd<sub>0.065sub>)>2sub>Ge>2sub>

    SciTech Connect (OSTI)

    Wang, C. H.; Poudel, L.; Taylor, A. E.; Lawrence, J. M.; Christianson, A. D.; Chang, S.; Rodriguez-Rivera, J. A.; Lynn, J. W.; Podlesnyak, A. A.; Ehlers, G.; Baumbach, R. E.; Bauer, E. D.; Gofryk, K.; Ronning, F.; McClellan, K. J.; Thompson, J. D.

    2015-01-14

    Electric resistivity, specific heat, magnetic susceptibility, and inelastic neutron scattering experi- ments were performed on a single crystal of the heavy fermion compound Ce(Ni<sub>0.935sub> Pd<sub>0.065sub>)>2sub>Ge>2sub> in order to study the spin fluctuations near an antiferromagnetic (AF) quantum critical point (QCP). The resistivity and the specific heat coefficient for T ≤ 1 K exhibit the power law behavior expected for a 3D itinerant AF QCP (ρ(T) ~ T3/2 and γ(T) ~ γ<sub>0sub> - bT1/2). However, for 2 ≤ T ≤ 10 K, the susceptibility and specific heat vary as log T and the resistivity varies linearly with temperature. Furthermore, despite the fact that the resistivity and specific heat exhibit the non-Fermi liquid behavior expected at a QCP, the correlation length, correlation time, and staggered susceptibility of the spin fluctuations remain finite at low temperature. We suggest that these deviations from the divergent behavior expected for a QCP may result from alloy disorder.

  19. Interfacial dislocations in (111) oriented (Ba<sub>0.7sub>Sr>0.3sub>)TiO>3sub> films on SrTiO<sub>3sub> single crystal

    SciTech Connect (OSTI)

    Shen, Xuan; Yamada, Tomoaki; Lin, Ruoqian; Kamo, Takafumi; Funakubo, Hiroshi; Wu, Di; Xin, Huolin L.; Su, Dong

    2015-10-08

    In this study, we have investigated the interfacial structure of epitaxial (Ba,Sr)TiO<sub>3sub> films grown on (111)-oriented SrTiO<sub>3sub> single-crystal substrates using transmission electron microscopy (TEM) techniques. Compared with the (100) epitaxial perovskite films, we observe dominant dislocation half-loop with Burgers vectors of a<110> comprised of a misfit dislocation along <112>, and threading dislocations along <110> or <100>. The misfit dislocation with Burgers vector of a <110> can dissociate into two ½ a <110> partial dislocations and one stacking fault. We found the dislocation reactions occur not only between misfit dislocations, but also between threading dislocations. Via three-dimensional electron tomography, we retrieved the configurations of the threading dislocation reactions. The reactions between threading dislocations lead to a more efficient strain relaxation than do the misfit dislocations alone in the near-interface region of the (111)-oriented (Ba<sub>0.7sub>Sr>0.3sub>)TiO>3sub> films.

  20. Fundamental Understanding of Methane-Carbon Dioxide-Water (CH<sub>4sub>-CO>2sub>-H>2sub>O) Interactions in Shale Nanopores under Reservoir Conditions. Quarterly Report.

    SciTech Connect (OSTI)

    Wang, Yifeng

    2015-10-27

    This project focuses on the systematic study of CH<sub>4sub>-CO>2sub>-H>2sub>O interactions in shale nanopores under high-pressure and high temperature reservoir conditions. The proposed work will help to develop new stimulation strategies to enable efficient resource recovery from fewer and less environmentally impactful wells.

  1. Li<sub>2sub>S encapsulated by nitrogen-doped carbon for lithium sulfur batteries

    SciTech Connect (OSTI)

    Chen, Lin; Liu, Yuzi; Ashuri, Maziar; Liu, Caihong; Shaw, Leon L.

    2014-09-26

    Using high-energy ball milling of the Li<sub>2sub>S plus carbon black mixture followed by carbonization of pyrrole, we have established a facile approach to synthesize Li<sub>2sub>S-plus-C composite particles of average size 400 nm, encapsulated by a nitrogen-doped carbon shell. Such an engineered core–shell structure exhibits an ultrahigh initial discharge specific capacity (1029 mAh/g), reaching 88% of the theoretical capacity (1,166 mAh/g of Li<sub>2sub>S) and thus offering the highest utilization of Li<sub>2sub>S in the cathode among all of the reported works for the encapsulated Li<sub>2sub>S cathodes. This Li<sub>2sub>S/C composite core with a nitrogen-doped carbon shell can still retain 652 mAh/g after prolonged 100 cycles. These superior properties are attributed to the nitrogen-doped carbon shell that can improve the conductivity to enhance the utilization of Li<sub>2sub>S in the cathode. As a result, fine particle sizes and the presence of carbon black within the Li<sub>2sub>S core may also play a role in high utilization of Li<sub>2sub>S in the cathode.

  2. A Rh<sub>xSy>/C Catalyst for the Hydrogen Oxidation and Hydrogen Evolution Reactions in HBr

    SciTech Connect (OSTI)

    Masud, Jahangir; Nguyena, Trung V.; Singh, Nirala; McFarland, Eric; Ikenberry, Myles; Hohn, Keith; Pan, Chun-Jern; Hwang, Bing-Joe

    2015-01-01

    Rhodium sulfide (Rh<sub>2sub>S>3sub>) on carbon support was synthesized by refluxing rhodium chloride with ammonium thiosulfate. Thermal treatment of Rh<sub>2sub>S>3sub> at high temperatures (600C to 850C) in presence of argon resulted in the transformation of Rh<sub>2sub>S>3sub> into Rh<sub>3sub>S>4sub>, Rh<sub>17sub>S>15sub> and Rh which were characterized by TGA/DTA, XRD, EDX, and deconvolved XPS analyses. The catalyst particle size distribution ranged from 3 to 12 nm. Cyclic voltammetry and rotating disk electrode measurements were used to evaluate the catalytic activity for hydrogen oxidation and evolution reactions in H<sub>2sub>SO>4sub> and HBr solutions. The thermally treated catalysts show high activity for the hydrogen reactions. The exchange current densities (i<sub>o>) of the synthesized Rh<sub>xSy> catalysts in H<sub>2sub>-saturated 1M H<sub>2sub>SO>4sub> and 1M HBr for HER and HOR were 0.9 mA/cm2 to 1.0 mA/cm2 and 0.8 to 0.9 mA/cm2, respectively. The lower i<sub>o> values obtained in 1M HBr solution compared to in H<sub>2sub>SO>4sub> might be due to the adsorption of Br- on the active surface. Stable electrochemical active surface area (ECSA) of Rh<sub>xSy> catalyst was obtained for CV scan limits between 0 V and 0.65 V vs. RHE. Scans with upper voltage limit beyond 0.65 V led to decreased and unreproducible ECSA measurements.

  3. Transfer between the cesium 6 {sup 2}P{sub 1/2} and 6 {sup 2}P{sub 3/2} levels induced by collisions with H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and C{sub 2}F{sub 6}

    SciTech Connect (OSTI)

    Pitz, Greg A.; Fox, Charles D.; Perram, Glen P.

    2011-09-15

    The cross sections of spin-orbit energy exchange between the cesium 6 {sup 2}P{sub 1/2}{r_reversible}6 {sup 2}P{sub 3/2} states induced by collisions with N{sub 2}, H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and C{sub 2}F{sub 6} were obtained for pressures less than 100 Torr at room temperature by means of steady-state laser-induced fluorescence techniques. The spin-orbit energy exchange rate with N{sub 2}, H{sub 2}, HD, D{sub 2}, CH{sub 4}, C{sub 2}H{sub 6}, CF{sub 4}, and C{sub 2}F{sub 6}, have been measured as {sigma}{sub 21}(6 {sup 2}P{sub 3/2}{yields}6 {sup 2}P{sub 1/2})= 16.3, 34.1, 30.0, 22.7, 21.4, 65.6, 64.8, and 137 A{sup 2} and {sigma}{sub 12}(6 {sup 2}P{sub 1/2}{yields}6 {sup 2}P{sub 3/2})= 1.8, 4.4, 4.1, 3.0, 2.9, 13.3, 9.7, and 16.3 A{sup 2}, respectively. Correlations of the spin-orbit transfer probabilities with rotational-energy defect and vibrational-energy defect have been shown.

  4. Reversible Exsolution of Nanometric Fe<sub>2sub>O>3 sub> Particles in BaFe<sub>2-xsub>(PO>4sub>)>2sub> (0 ? x ? 2/3):The Logic of Vacancy Ordering in Novel Metal-Depleted Two-Dimensional Lattices

    SciTech Connect (OSTI)

    Alcover, Ignacio Blazquez; David, Rnald; Daviero-Minaud, Sylvie; Filimonov, Dmitry; Huv, Marielle; Roussel, Pascal; Kabbour, Houria; Mentr, Olivier

    2015-08-12

    We show here that the exsolution of Fe2+ ions out of two-dimensional (2D) honeycomb layers of BaFe<sub>2sub>(PO>4sub>)>2 sub>into iron-deficient BaFe<sub>2xsub>(PO>4sub>)>2sub> phases and nanometric ?-Fe<sub>2sub>O>3sub> (typically 50 nm diameter at the grain surface) is efficient and reversible until x = 2/3 in mild oxidizing/reducing conditions. It corresponds to the renewable conversion of 12 wt % of the initial mass into iron oxide. After analyzing single crystal X-ray diffraction data of intermediate members x = 2/7, x = 1/3, x = 1/2 and the ultimate Fe-depleted x = 2/3 term, we then observed a systematic full ordering between Fe ions and vacancies (V<sub>Fe>) that denote unprecedented easy in-plane metal diffusion driven by the Fe2+/Fe3+ redox. Besides the discovery of a diversity of original depleted triangular <sub>?>{Fe2/3+<sub>2xsub>O>6sub>} topologies, we propose a unified model correlating the x Fe-removal and the experimental Fe/V<sub>Fe> ordering into periodic one-dimensional motifs paving the layers, gaining insights into predictive crystahemistry of complex low dimensional oxides. When we increased the x values it led to a progressive change of the materials from 2D ferromagnets (Fe2+) to 2D ferrimagnets (Fe2/3+) to antiferromagnets for x = 2/3 (Fe3+).

  5. Electron motion in the gases CF/sub 4/, C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, and n-C/sub 4/F/sub 10/

    SciTech Connect (OSTI)

    Hunter, S.R.; Carter, J.G.; Christophorou, L.G.

    1988-07-01

    The drift velocity w of electrons has been measured in the perfluoroalkanes n-C/sub N/F/sub 2//sub N//sub +2/ (N = 1--4) over the density-reduced electric field (E/N) range 0.03 x 10/sup -17/ V cm/sup 2/less than or equal toE/Nless than or equal to500 x 10/sup -17/ V cm/sup 2/ using a pulsed Townsend experimental method. The present measurements of w are the first to be obtained for C/sub 2/F/sub 6/, C/sub 3/F/sub 8/, and n-C/sub 4/F/sub 10/ at low E/N values. The electron-drift-velocity measurements in C/sub 3/F/sub 8/ and n-C/sub 4/F/sub 10/ are dependent on gas pressure at high E/N values, even after allowing for nonequilibrium and boundary corrections to the measured electron swarm transit time. This is the first observation of a pressure dependence in the electron drift velocity in these gases and is believed to be due to changes in the electron energy distribution function f(epsilon-c,E/N) with gas pressure resulting from increases in the density-normalized electron attachment coefficient eta/N with gas pressure. The perfluoroalkanes CF/sub 4/, C/sub 2/F/sub 6/, and C/sub 3/F/sub 8/ exhibit regions of pronounced negative differential conductivity (NDC) similar to but smaller in magnitude than that in CH/sub 4/. Possible mechanisms leading to the observation of NDC effects in these molecular gases are discussed.

  6. Insulating and metallic spin glass in K<sub>xFe>2-?-ysub>NiySe>2sub> (0.06 ? y ? 1.44 ) single crystals

    SciTech Connect (OSTI)

    Ryu, Hyejin; Abeykoon, Milinda; Wang, Kefeng; Lei, Hechang; Lazarevic, N.; Warren, J. B.; Bozin, E. S.; Popovic, Z. V.; Petrovic, C.

    2015-05-04

    We report electron doping effects by Ni in K<sub>xFe>2-?-ysub>Niy>Se? (0.06 ? y ? 1.44) single crystal alloys. A rich ground state phase diagram is observed. Thus, a small amount of Ni (~ 4%) suppressed superconductivity below 1.8 K, inducing insulating spin glass magnetic ground state for higher Ni content. With further Ni substitution, metallic resistivity is restored. For high Ni concentration in the lattice the unit cell symmetry is high symmetry I4/mmm with no phase separation whereas both I4/m + I4/mmm space groups were detected in the phase separated crystals when concentration of Ni < Fe. The absence of superconductivity coincides with the absence of crystalline Fe vacancy order.

  7. Synthesis and crystal structure of the palladium oxides NaPd{sub 3}O{sub 4}, Na{sub 2}PdO{sub 3} and K{sub 3}Pd{sub 2}O{sub 4}

    SciTech Connect (OSTI)

    Panin, Rodion V. Khasanova, Nellie R.; Abakumov, Artem M.; Antipov, Evgeny V.; Tendeloo, Gustaaf van; Schnelle, Walter

    2007-05-15

    NaPd{sub 3}O{sub 4}, Na{sub 2}PdO{sub 3} and K{sub 3}Pd{sub 2}O{sub 4} have been prepared by solid-state reaction of Na{sub 2}O{sub 2} or KO{sub 2} and PdO in sealed silica tubes. Crystal structures of the synthesized phases were refined by the Rietveld method from X-ray powder diffraction data. NaPd{sub 3}O{sub 4} (space group Pm3-barn, a=5.64979(6) A, Z=2) is isostructural to NaPt{sub 3}O{sub 4}. It consists of NaO{sub 8} cubes and PdO{sub 4} squares, corner linked into a three-dimensional framework where the planes of neighboring PdO{sub 4} squares are perpendicular to each other. Na{sub 2}PdO{sub 3} (space group C2/c, a=5.3857(1) A, b=9.3297(1) A, c=10.8136(2) A, {beta}=99.437(2){sup o}, Z=8) belongs to the Li{sub 2}RuO{sub 3}-structure type, being the layered variant of the NaCl structure, where the layers of octahedral interstices filled with Na{sup +} and Pd{sup 4+} cations alternate with Na{sub 3} layers along the c-axis. Na{sub 2}PdO{sub 3} exhibits a stacking disorder, detected by electron diffraction and Rietveld refinement. K{sub 3}Pd{sub 2}O{sub 4}, prepared for the first time, crystallizes in the orthorhombic space group Cmcm (a=6.1751(6) A, b=9.1772(12) A, c=11.3402(12) A, Z=4). Its structure is composed of planar PdO{sub 4} units connected via common edges to form parallel staggered PdO{sub 2} strips, where potassium atoms are located between them. Magnetic susceptibility measurements of K{sub 3}Pd{sub 2}O{sub 4} reveal a Curie-Weiss behavior in the temperature range above 80 K. - Graphical abstract: Na{sub 2}PdO{sub 3} (space group C2/c, a=5.3857(1) A, b=9.3297(1) A, c=10.8136(2) A, {beta}=99.437(2), Z=8) belongs to the Li{sub 2}RuO{sub 3}-structure type, being the layered variant of the NaCl structure, where the layers of octahedral interstices filled with Na{sup +} and Pd{sup 4+} cations (NaPd{sub 2}O{sub 6} slabs) alternate with Na{sub 3} layers along the c-axis.

  8. Structural relationships between new carbide La{sub 14}Sn(MnC{sub 6}){sub 3} and fully ordered La{sub 11}(MnC{sub 6}){sub 3}

    SciTech Connect (OSTI)

    Zaikina, Julia V.; Zhou, Haidong; Latturner, Susan E.

    2010-12-15

    Crystals of the ternary La{sub 11}(MnC{sub 6}){sub 3} and new quaternary carbide La{sub 14}Sn(MnC{sub 6}){sub 3} phases were grown from La/Ni eutectic flux and their structures were determined by means of X-ray single crystal diffraction. La{sub 11}(MnC{sub 6}){sub 3} is a new superstructure variant of La{sub 3.67}MnC{sub 6} (previously reported disordered subcell: P6{sub 3}/m; a{sub 0}=8.806 A; c{sub 0}=5.329 A, Z=2). The superstructure (R3-bar ; a={radical}3a{sub 0}=15.2649(9) A; c=3c{sub 0}=16.013(1) A, Z=6; R{sub 1}=0.022) is realized by complete ordering of the La chains within the columns of face-sharing carbon octahedra, with alternating La-La distances leading to R-centering and enlargement of the unit cell. The structure of the quaternary carbide La{sub 14}Sn(MnC{sub 6}){sub 3} (P6-bar ; a=8.756(1) A; c=10.483(2) A, Z=1; R{sub 1}=0.026) is closely related to that of La{sub 11}(MnC{sub 6}){sub 3} with part of the MnC{sub 6} units replaced by Sn atoms. The structure and precise composition of La{sub 14}Sn(MnC{sub 6}){sub 3} can be derived from that of La{sub 11}(MnC{sub 6}){sub 3} by taking into account the extent of this substitution and variation in lanthanum siting in the chain of carbon octahedra. Band structure calculations indicate both phases are metallic; the La{sub 11}(MnC{sub 6}){sub 3} phase is stabilized by the ordering of La atoms which induces a pseudogap at E{sub F}. -- La{sub 11}(MnC{sub 6}){sub 3} with fully ordered superstructure and a new carbide La{sub 14}Sn(MnC{sub 6}){sub 3} were obtained from La/Ni eutectic flux. Display Omitted

  9. Magnetic order in RBa/sub 2/Cu/sub 2/O/sub 6+//sub x/ (invited)

    SciTech Connect (OSTI)

    Lynn, J.W.; Li, W.

    1988-11-15

    Neutron scattering results on the RBa/sub 2/ Cu/sub 3/ O/sub 6+//sub x/ (R = rare earth) class of systems are reviewed. For the oxygen-deficient systems (x<0.5), which are semiconducting, the Cu ions are observed to order with Neel temperatures as high as 500 K. The magnetic structure consists of strong nearest-neighbor antiferromagnetic couplings of the Cu spins within the Cu-O/sub 2/ layers, while nearest-neighbor spins in adjacent layers are also aligned antiferromagnetically. The moments are constrained in the tetragonal plane. At lower temperatures the Cu moments in the oxygen-deficient ''chain'' layers also order antiferromagnetically, with a moment that can be quite substantial (approx. 1/2 ..mu../sub B/). Both transition temperatures are very sensitive to the oxygen concentration. The magnetic heavy rare-earth compounds, on the other hand, order antiferromagnetically at very low temperatures, analogous to the ''conventional'' magnetic-superconductor systems such as RMo/sub 6/ S/sub 8/ and RRh/sub 4/ B/sub 4/. The ordering is not very sensitive to the oxygen concentration, and the antiferromagnetic state coexists with superconductivity. Differences in the ordering behavior are ascribed to crystal-field effects, which are briefly discussed. Finally, small-angle neutron scattering results in the vicinity of the superconducting transition temperature are also discussed.

  10. Facile synthesis of Ba<sub>1-xsub>Kx>Fe?As? superconductors via hydride route

    SciTech Connect (OSTI)

    Zaikina, Julia V. [Univ. of California at Davis, Davis, CA (United States); Batuk, Maria [Univ. of Antwerp, Antwerp (Belgium); Abakumov, Artem M. [Univ. of Antwerp, Antwerp (Belgium); Navrotsky, Alexandra [Univ. of California at Davis, Davis, CA (United States); Kauzlarich, Susan M. [Univ. of California at Davis, Davis, CA (United States)

    2014-12-03

    We have developed a fast, easy, and scalable synthesis method for Ba<sub>1-xsub>Kx>Fe?As? (0 ? x ? 1) superconductors using hydrides BaH? and KH as a source of barium and potassium metals. Synthesis from hydrides provides better mixing and easier handling of the starting materials, consequently leading to faster reactions and/or lower synthesis temperatures. The reducing atmosphere provided by the evolved hydrogen facilitates preparation of oxygen-free powders. By a combination of methods we have shown that Ba<sub>1-xsub>Kx>Fe?As? obtained via hydride route has the same characteristics as when it is prepared by traditional solid-state synthesis. Refinement from synchrotron powder X-ray diffraction data confirms a linear dependence of unit cell parameters upon K content as well as the tetragonal to orthorhombic transition at low temperatures for compositions with x < 0.2. Magnetic measurements revealed dome-like dependence of superconducting transition temperature T<sub>c> upon K content with a maximum of 38 K for x close to 0.4. Electron diffraction and high-resolution high-angle annular dark-field scanning transmission electron microscopy indicates an absence of Ba/K ordering, while local inhomogeneity in the Ba/K distribution takes place at a scale of several angstroms along [110] crystallographic direction.

  11. Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A.; Daumit, K.; Hunter, J.; et al

    2015-02-18

    We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gasmore » and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25–50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas–particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.« less

  12. Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A. J.; Daumit, K. E.; Hunter, J. F.; et al

    2015-07-16

    We measured a large suite of gas- and particle-phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas andmore » particle phases, the latter being detected by temperature-programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO–HR-ToF-CIMS are highly correlated with, and explain at least 25–50 % of, the organic aerosol mass measured by an Aerodyne aerosol mass spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from high molecular weight organics and/or oligomers (i.e., multi-phase accretion reaction products). Approximately 50 % of the HR-ToF-CIMS particle-phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption-temperature-based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.« less

  13. Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Carrasquillo, A.; Daumit, K.; Hunter, J.; et al

    2015-02-18

    We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gasmore »and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25–50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas–particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.« less

  14. Sub-micron filter

    DOE Patents [OSTI]

    Tepper, Frederick; Kaledin, Leonid

    2009-10-13

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.

  15. Controlling superconductivity in La<sub>2-xsub>SrxCuO>4+?sub> by ozone and vacuum annealing

    SciTech Connect (OSTI)

    Leng, Xiang; Bozovic, Ivan

    2014-11-21

    In this study we performed a series of ozone and vacuum annealing experiments on epitaxial La<sub>2-xsub>SrxCuO>4+?sub> thin films. The transition temperature after each annealing step has been measured by the mutual inductance technique. The relationship between the effective doping and the vacuum annealing time has been studied. Short-time ozone annealing at 470 C oxidizes an underdoped film all the way to the overdoped regime. The subsequent vacuum annealing at 350 C to 380 C slowly brings the sample across the optimal doping point back to the undoped, non-superconducting state. Several ozone and vacuum annealing cycles have been done on the same sample and the effects were found to be repeatable and reversible Vacuum annealing of ozone-loaded LSCO films is a very controllable process, allowing one to tune the doping level of LSCO in small steps across the superconducting dome, which can be used for fundamental physics studies.

  16. Electron-phonon coupling and thermal transport in the thermoelectric compound Mo<sub>3sub>Sb>7–xsub>Tex>

    SciTech Connect (OSTI)

    Bansal, Dipanshu; Li, Chen W.; Said, Ayman H.; Abernathy, Douglas L.; Yan, Jiaqiang; Delaire, Olivier A.

    2015-12-07

    Phonon properties of Mo<sub>3sub>Sb>7–xsub>Tex> (x = 0, 1.5, 1.7), a potential high-temperature thermoelectric material, have been studied with inelastic neutron and x-ray scattering, and with first-principles simulations. The substitution of Te for Sb leads to pronounced changes in the electronic struc- ture, local bonding, phonon density of states (DOS), dispersions, and phonon lifetimes. Alloying with tellurium shifts the Fermi level upward, near the top of the valence band, resulting in a strong suppression of electron-phonon screening, and a large overall stiffening of interatomic force- constants. The suppression in electron-phonon coupling concomitantly increases group velocities and suppresses phonon scattering rates, surpassing the effects of alloy-disorder scattering, and re- sulting in a surprising increased lattice thermal conductivity in the alloy. We also identify that the local bonding environment changes non-uniformly around different atoms, leading to variable perturbation strengths for different optical phonon branches. The respective roles of changes in phonon group velocities and phonon lifetimes on the lattice thermal conductivity are quantified. Lastly, our results highlight the importance of the electron-phonon coupling on phonon mean-free-paths in this compound, and also estimates the contributions from boundary scattering, umklapp scattering, and point-defect scattering.

  17. Microdomain Formation, Oxidation, and Cation Ordering in LaCa<sub>2sub>Fe>3sub>O>8+ysub>

    SciTech Connect (OSTI)

    Price, Patrick M.; Browning, Nigel D.; Butt, Darryl P.

    2015-03-23

    The compound LaCa<sub>2sub>Fe>3sub>O>8+ysub>, also known as the Grenier phase, is known to undergo an order-disorder transformation (ODT) at high temperatures. Oxidation has been observed when the compound is cooled in air after the ODT. In this study, we have synthesized the Grenier compound in air using traditional solid state reactions and investigated the structure and composition before and after the ODT. Thermal analysis showed that the material undergoes an order-disorder transformation in both oxygen and argon atmospheres with dynamic, temperature dependent, oxidation upon cooling. Results from scanning transmission electron microscopy (STEM) suggest that the Grenier phase has preferential segregation of Ca and La on the two crystallographic A-sites before the ODT, but a random distribution above the ODT temperature. Furthermore, STEM images suggest the possibility that oxygen excess may exist in La-rich regions within microdomains rather than at microdomain boundaries.

  18. Volatile Organic Compound Investigation Results, 300 Area, Hanford Site, Washington

    SciTech Connect (OSTI)

    Peterson, Robert E.; Williams, Bruce A.; Smith, Ronald M.

    2008-07-07

    Unexpectedly high concentrations of volatile organic compounds (VOC) were discovered while drilling in the unconfined aquifer beneath the Hanford Site’s 300 Area during 2006. The discovery involved an interval of relatively finer-grained sediment within the unconfined aquifer, an interval that is not sampled by routine groundwater monitoring. Although VOC contamination in the unconfined aquifer has been identified and monitored, the concentrations of newly discovered contamination are much higher than encountered previously, with some new results significantly higher than the drinking water standards. The primary contaminant is trichloroethene, with lesser amounts of tetrachloroethene. Both chemicals were used extensively as degreasing agents during the fuels fabrication process. A biological degradation product of these chemicals, 1,2-dichloroethene, was also detected. To further define the nature and extent of this contamination, additional characterization drilling was undertaken during 2007. Four locations were drilled to supplement the information obtained at four locations drilled during the earlier investigation in 2006. The results of the combined drilling indicate that the newly discovered contamination is limited to a relatively finer-grained interval of Ringold Formation sediment within the unconfined aquifer. The extent of this contamination appears to be the area immediately east and south of the former South Process Pond. Samples collected from the finer-grained sediment at locations along the shoreline confirm the presence of the contamination near the groundwater/river interface. Contamination was not detected in river water that flows over the area where the river channel potentially incises the finer-grained interval of aquifer sediment. The source for this contamination is not readily apparent. A search of historical documents and the Hanford Waste Information Data System did not provide definitive clues as to waste disposal operations and/or spills that might have resulted in groundwater contamination in this sediment, although several relatively small accidental releases of VOCs have occurred in the past in the northern portion of the 300 Area. It is likely that large quantities of degreasing solutions were disposed to the North and South Process Ponds during the 1950s and 1960s, and that evidence for them in the upper portion of the unconfined aquifer has been removed because of groundwater movement through the much more transmissive sediment. Also, investigations to date have revealed no evidence to suggest that a dense, non-aqueous phase liquid remains undetected in the subsurface. Potential pathways for contamination to migrate from this finer-grained sediment include groundwater movement through the interval to offshore locations in the Columbia River channel, dispersion out of the finer-grained interval into the overlying transmissive sediment (again, with transport to the riverbed), and potential future withdrawal via water supply wells.

  19. Electric-field-induced strain effects on the magnetization of a Pr<sub>0.67sub>Sr>0.33sub>MnO>3sub> film

    SciTech Connect (OSTI)

    Zhang, B.; Sun, C. -J.; Lu, W.; Venkatesan, T.; Han, M. -G.; Zhu, Y.; Chen, J.; Chow, G. M.

    2015-05-26

    The electric-field control of magnetic properties of Pr<sub>0.67sub>Sr>0.33sub>MnO>3sub> (PSMO) film on piezoelectric Pb(Mg<sub>1/3sub>Nb>2/3sub>)O>3sub>-PbTiO>3sub> (PMNT) substrate was investigated. The piezoelectric response of the PMNT substrate to the electric field produced strain that was coupled to the PSMO film. The in-plane compressive (tensile) strain increased (decreased) the magnetization. The change of magnetic moment was associated with the Mn ions. First principle simulations showed that the strain-induced electronic redistribution of the two e<sub>g> orbitals (3d<sub>z>2 and 3d<sub>x>2<sub>-y>2) of Mn ions was responsible for the change of magnetic moment. This work demonstrates that the magnetoelectric effect in manganite/piezoelectric hetero-structures originates from the change in eg orbital occupancy of Mn ions induced by strain rather than the interfacial effect.

  20. Crystal structure and physical properties of quaternary clathrates Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y}, Ba{sub 8}(Zn,Cu){sub x}Ge{sub 46-x} and Ba{sub 8}(Zn,Pd){sub x}Ge{sub 46-x}

    SciTech Connect (OSTI)

    Nasir, Navida; Grytsiv, Andriy; Melnychenko-Koblyuk, Nataliya; Rogl, Peter; Bednar, Ingeborg; Bauer, Ernst

    2010-10-15

    Three series of vacancy-free quaternary clathrates of type I, Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y}, Ba{sub 8}(Zn,Cu){sub x}Ge{sub 46-x}, and Ba{sub 8}(Zn,Pd){sub x}Ge{sub 46-x}, have been prepared by reactions of elemental ingots in vacuum sealed quartz at 800 {sup o}C. In all cases cubic primitive symmetry (space group Pm3n, a{approx}1.1 nm) was confirmed for the clathrate phase by X-ray powder diffraction and X-ray single crystal analyses. The lattice parameters show a linear increase with increase in Ge for Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y}. M atoms (Zn, Pd, Cu) preferably occupy the 6d site in random mixtures. No defects were observed for the 6d site. Site preference of Ge and Si in Ba{sub 8}Zn{sub x}Ge{sub 46-x-y}Si{sub y} has been elucidated from X-ray refinement: Ge atoms linearly substitute Si in the 24k site whilst a significant deviation from linearity is observed for occupation of the 16i site. A connectivity scheme for the phase equilibria in the 'Ba{sub 8}Ge{sub 46}' corner at 800 {sup o}C has been derived and a three-dimensional isothermal section at 800 {sup o}C is presented for the Ba-Pd-Zn-Ge system. Studies of transport properties carried out for Ba{sub 8{l_brace}}Cu,Pd,Zn{r_brace}{sub x}Ge{sub 46-x} and Ba{sub 8}Zn{sub x}Si{sub y}Ge{sub 46-x-y} evidenced predominantly electrons as charge carriers and the closeness of the systems to a metal-to-insulator transition, fine-tuned by substitution and mechanical processing of starting material Ba{sub 8}Ge{sub 43}. A promising figure of merit, ZT {approx}0.45 at 750 K, has been derived for Ba{sub 8}Zn{sub 7.4}Ge{sub 19.8}Si{sub 18.8}, where pricey germanium is exchanged by reasonably cheap silicon. - Graphical abstract: Quaternary phase diagram of Ba-Pd-Zn-Ge system at 800 {sup o}C.

  1. Magnetic domain structure and domain-wall energy in UFe{sub 8}Ni{sub 2}Si{sub 2} and UFe{sub 6}Ni{sub 4}Si{sub 2} intermetallic compounds

    SciTech Connect (OSTI)

    Wyslocki, J.J.; Suski, W.; Wochowski, K.

    1994-03-01

    Magnetic domain structures in the UFe{sub 8}Ni{sub 2}Si{sub 2} and UFe{sub 6}Ni{sub 4}Si{sub 2} compounds were studied using the powder pattern method. The domain structure observed is typical for uniaxial materials. The domain-wall energy density {gamma} was determined from the average surface domain width D{sub s} observed on surfaces perpendicular to the easy axis as equal to 16 erg/cm{sup 2} for UFe{sub 8}Ni{sub 2}Si{sub 2} and 10 erg/cm{sup 2} for UFe{sub 6}Ni{sub 4}Si{sub 2}. Moreover, the critical diameter for single domain particle D{sub c} was calculated for the studied compounds.

  2. Synthesis and crystal structure of (NH{sub 4}){sub 3}[UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 2}[UO{sub 2}(CH{sub 3}COO)(NCS){sub 2}(H{sub 2}O)

    SciTech Connect (OSTI)

    Serezhkina, L. B.; Peresypkina, E. V.; Virovets, A. V.; Karasev, M. O.

    2010-01-15

    Single crystals of the compound (NH{sub 4}){sub 3}[UO{sub 2}(CH{sub 3}COO){sub 3}]{sub 2}[UO{sub 2}(CH{sub 3}COO)(NCS){sub 2}(H{sub 2}O)] (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 18.3414(6) A, b = 16.3858(7) A, c = 12.4183(5) A, {beta} = 92.992(1){sup o}, space group C2/c, Z = 4, V = 3727.1(3) A{sup 3}, and R = 0.0253. The uranium-containing structural units of crystals I are mononuclear complexes of two types with an island structure, i.e., the [UO{sub 2}(CH{sub 3}COO){sub 3}]{sup -} anionic complexes belonging to the crystal-chemical group (AB{sub 3}{sup 01} = UO{sub 2}{sup 2+}, B{sup 01} = CH{sub 3}COO{sup -}) of the uranyl complexes and the [UO{sub 2}(CH{sub 3}COO)(NCS){sub 2}(H{sub 2}O)]{sup -} anionic complexes belonging to the crystal-chemical group AB{sup 01}M{sub 3}{sup 1} (A = UO{sub 2}{sup 2+}, B{sup 01} = CH{sub 3}COO{sup -}, M{sup 1} = NCS{sup -} or H{sub 2}O).

  3. Structure and optical properties of a noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3}

    SciTech Connect (OSTI)

    Xia, M.J.; Li, R.K.

    2013-01-15

    A new noncentrosymmetric borate, RbSr{sub 4}(BO{sub 3}){sub 3} (abbreviated as RSBO), has been grown from Rb{sub 2}O--B{sub 2}O{sub 3}--RbF flux and its crystal structure was determined by single crystal x-ray diffraction. It crystallizes in space group Ama2 with cell parameters of a=11.128(10) A, b=12.155(15) A, c=6.952(7) A, Z=4. The basic structural units are isolated planar BO{sub 3} groups. Second harmonic generation (SHG) test of the title compound by the Kurtz-Perry method shows that RSBO can be phase matchable with an effective SHG coefficient about two-thirds as large as that of KH{sub 2}PO{sub 4} (KDP). Finally, based on the anionic group approximation, the optical properties of the title compound are compared with those of the structure-related apatite-like compounds with the formula 'A{sub 5}(TO{sub n}){sub 3}X'. - Graphical abstract: RbSr{sub 4}(BO{sub 3}){sub 3} and some other borate NLO compounds, namely Ca{sub 5}(BO{sub 3}){sub 3}F RCa{sub 4}(BO{sub 3}){sub 3}O (R=Y or Gd) and Na{sub 3}La{sub 2}(BO{sub 3}){sub 3} can be viewed as the derivatives of apatite. They have similar formula composed of five cations and three anion groups (we call them 5/3 structures). The detailed SHG coefficients and optical properties of the apatite-like NLO crystals were compared and summarized. Highlights: Black-Right-Pointing-Pointer A new noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3} was grown from flux. Black-Right-Pointing-Pointer The RbSr{sub 4}(BO{sub 3}){sub 3} can be viewed as a derivative of the apatite-like structure. Black-Right-Pointing-Pointer The structure and its relationship to the optical properties of RbSr{sub 4}(BO{sub 3}){sub 3} are compared with other NLO crystals with apatite-like structures. Black-Right-Pointing-Pointer The basic structural units are the planar BO{sub 3} groups in the structure. Black-Right-Pointing-Pointer Second harmonic generation (SHG) test shows that RbSr{sub 4}(BO{sub 3}){sub 3} can be phase matchable with an effective SHG coefficient about two-thirds as large as that of KH{sub 2}PO{sub 4}.

  4. Volatile organic compounds (VOCs): Remediation for wastewater. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1993-11-01

    The bibliography contains citations concerning wastewater contamination by volatile organic materials and the technology for reclamation. Remediation techniques discussed include use of activated carbon, activated sludge, oxidation, scrubbing, vapor stripping, biodegradation, and other degradative treatments. Articles include remediation of soils contaminated by volatile wastes. The citations examine a variety of compounds, including aromatic hydrocarbons, petroleum wastes, chlorinated organics, and other volatile materials. (Contains a minimum of 215 citations and includes a subject term index and title list.)

  5. Direct evidence for a pressure-induced nodal superconducting gap in the Ba<sub>0.65sub>Rb>0.35sub>Fe>2sub>As>2sub> superconductor

    SciTech Connect (OSTI)

    Guguchia, Z.; Amato, A.; Kang, J.; Luetkens, H.; Biswas, P. K.; Prando, G.; von Rohr, F.; Bukowski, Z.; Shengelaya, A.; Keller, H.; Morenzoni, E.; Fernandes, Rafael M.; Khasanov, R.

    2015-11-09

    The superconducting gap structure in iron-based high-temperature superconductors (Fe-HTSs) is non-universal. Contrasting with other unconventional superconductors, in the Fe-HTSs both d-wave and extended s-wave pairing symmetries are close in energy. Probing the proximity between these very different superconducting states and identifying experimental parameters that can tune them is of central interest. Here we report high-pressure muon spin rotation experiments on the temperature-dependent magnetic penetration depth in the optimally doped nodeless s-wave Fe-HTS Ba<sub>0.65sub>Rb>0.35sub>Fe>2sub>As>2sub>. Upon pressure, a strong decrease of the penetration depth in the zero-temperature limit is observed, while the superconducting transition temperature remains nearly constant. More importantly, the low-temperature behaviour of the inverse-squared magnetic penetration depth, which is a direct measure of the superfluid density, changes qualitatively from an exponential saturation at zero pressure to a linear-in-temperature behaviour at higher pressures, indicating that hydrostatic pressure promotes the appearance of nodes in the superconducting gap.

  6. Large magnetic entropy change and magnetoresistance in a Ni<sub>41sub>Co>9sub>Mn>40sub>Sn>10sub> magnetic shape memory alloy

    SciTech Connect (OSTI)

    Huang, L.; Cong, D. Y.; Ma, L.; Nie, Z. H.; Wang, M. G.; Wang, Z. L.; Suo, H. L.; Ren, Y.; Wang, Y. D.

    2015-07-02

    A polycrystalline Ni<sub>41sub>Co>9sub>Mn>40sub>Sn>10sub> (at. %) magnetic shape memory alloy was prepared by arc melting and characterized mainly by magnetic measurements, in-situ high-energy X-ray diffraction (HEXRD), and mechanical testing. A large magnetoresistance of 53.8% (under 5 T) and a large magnetic entropy change of 31.9 J/(kg K) (under 5 T) were simultaneously achieved. Both of these values are among the highest values reported so far in Ni-Mn-Sn-based Heusler alloys. The large magnetic entropy change, closely related to the structural entropy change, is attributed to the large unit cell volume change across martensitic transformation as revealed by our in-situ HEXRD experiment. Furthermore, good compressive properties were also obtained. Lastly, the combination of large magnetoresistance, large magnetic entropy change, and good compressive properties, as well as low cost makes this alloy a promising candidate for multifunctional applications.

  7. Magnetocaloric effect in gadolinium-oxalate framework Gd{sub 2}(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 6}⋅(0{sub ⋅}6H{sub 2}O)

    SciTech Connect (OSTI)

    Sibille, Romain Didelot, Emilie; Mazet, Thomas; Malaman, Bernard; François, Michel

    2014-12-01

    Magnetic refrigerants incorporating Gd{sup 3+} ions and light organic ligands offer a good balance between isolation of the magnetic centers and their density. We synthesized the framework material Gd{sub 2}(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 6}⋅0.6H{sub 2}O by a hydrothermal route and characterized its structure. The honeycomb lattice of Gd{sup 3+} ions interlinked by oxalate ligands in the (a,c) plane ensures their decoupling in terms of magnetic exchange interactions. This is corroborated by magnetic measurements indicating negligible interactions between the Gd{sup 3+} ions in this material. The magnetocaloric effect was evaluated from isothermal magnetization measurements. The maximum entropy change −ΔS{sub M}{sup max} reaches 75.9 mJ cm{sup −3} K{sup −1} (around 2 K) for a moderate field change (2 T)

  8. Simulation of CO<sub>2sub> Storage

    SciTech Connect (OSTI)

    McNabb, W.; Myers, K.

    2015-10-26

    This report is a compilation of Lawrence Livermore National Laboratory’s (LLNL) accomplishments on CO<sub>2sub> storage simulation and modeling research, performed for the US-­China Clean Energy Research Center (CERC). Within the CERC project management structure, this work is referred to as Subtask 6.4.a Simulation and Modeling. The task falls under CERC’s Advanced Coal Technology Consortium (ACTC) Research Theme 6—CO<sub>2sub> Sequestration Capacity and Near-­Term Opportunities. The goals of the task were to develop new CO<sub>2sub> sequestration simulation approaches and tools, then apply them to CO<sub>2sub> storage projects in the U.S. and China. Work on this task paused when funding was redirected to CERC’s other efforts. Two sections of this report provide valuable snapshot of LLNL’s progress when funding was curtailed: 1) Section 5.2.2 is a 14-­page presentation written January 8, 2013; and 2) Section 5.1.3 is a progress report from the first quarter of Fiscal year 2013.

  9. Structure tracking aided design and synthesis of Li<sub>3sub>V>2sub>(PO>4sub>)>3sub> nanocrystals as high-power cathodes for lithium ion batteries

    SciTech Connect (OSTI)

    Wang, Liping; Bai, Jianming; Gao, Peng; Wang, Xiaoya; Looney, J. Patrick; Wang, Feng

    2015-07-30

    In this study, preparing new electrode materials with synthetic control of phases and electrochemical properties is desirable for battery applications but hardly achievable without knowing how the synthesis reaction proceeds. Herein, we report on structure tracking-aided design and synthesis of single-crystalline Li<sub>3sub>V>2sub>(PO>4sub>)>3sub> (LVP) nanoparticles with extremely high rate capability. A comprehensive investigation was made to the local structural orderings of the involved phases and their evolution toward forming LVP phase using in situ/ex situ synchrotron X-ray and electron-beam diffraction, spectroscopy, and imaging techniques. The results shed light on the thermodynamics and kinetics of synthesis reactions and enabled the design of a cost-efficient synthesis protocol to make nanocrystalline LVP, wherein solvothermal treatment is a crucial step leading to an amorphous intermediate with local structural ordering resembling that of LVP, which, upon calcination at moderate temperatures, rapidly transforms into the desired LVP phase. The obtained LVP particles are about 50 nm, coated with a thin layer of amorphous carbon and featured with excellent cycling stability and rate capability – 95% capacity retention after 200 cycles and 66% theoretical capacity even at a current rate of 10 C. The structure tracking based method we developed in this work offers a new way of designing battery electrodes with synthetic control of material phases and properties.

  10. Environmental Aspects of Two Volatile Organic Compound Groundwater Treatment Designs at the Rocky Flats Site - 13135

    SciTech Connect (OSTI)

    Michalski, Casey C.; DiSalvo, Rick; Boylan, John

    2013-07-01

    DOE's Rocky Flats Site in Colorado is a former nuclear weapons production facility that began operations in the early 1950's. Because of releases of hazardous substances to the environment, the federally owned property and adjacent offsite areas were placed on the CERCLA National Priorities List in 1989. The final remedy was selected in 2006. Engineered components of the remedy include four groundwater treatment systems that were installed before closure as CERCLA-accelerated actions. Two of the systems, the Mound Site Plume Treatment System and the East Trenches Plume Treatment System, remove low levels of volatile organic compounds using zero-valent iron media, thereby reducing the loading of volatile organic compounds in surface water resulting from the groundwater pathway. However, the zero-valent iron treatment does not reliably reduce all volatile organic compounds to consistently meet water quality goals. While adding additional zero-valent iron media capacity could improve volatile organic compound removal capability, installation of a solar powered air-stripper has proven an effective treatment optimization in further reducing volatile organic compound concentrations. A comparison of the air stripper to the alternative of adding additional zero-valent iron capacity to improve Mound Site Plume Treatment System and East Trenches Plume Treatment System treatment based on several key sustainable remediation aspects indicates the air stripper is also more 'environmentally friendly'. These key aspects include air pollutant emissions, water quality, waste management, transportation, and costs. (authors)

  11. Ordered structures in YBa/sub 2/Cu/sub 3/O/sub 7-y/, La/sub 2-x/Sr/sub x/CuO/sub 4-par. delta/ and related perovskites

    SciTech Connect (OSTI)

    Mitchell, T.E.; Roy, T.; Fisk, Z.; Smith, J.L.

    1988-01-01

    Electron microscopy and electron diffraction studies have been performed on the superconducting oxides YBa/sub 2/Cu/sub 3/O/sub 7-y/, GdBa/sub 2/Cu/sub 3/O/sub 7-y/ and La/sub 2-x/Sr/sub x/CuO/sub 4-par. delta/ as well as the related perovskites La/sub 2/CuO/sub 4/, Eu/sub 2/CuO/sub 4/ and Gd/sub 2/CuO/sub 4/. Extra reflections are commonly observed in all the cases. For example, in the 123 compounds, in situ heating leads to transformations from orthorhombic to tetragonal with a loss of twin structure; on cooling the oxygen vacancies re-order in the basal plane to give 1/3(100)* or 1/4(110)* diffraction spots. In tetragonal Eu/sub 2/CuO/sub 4/ and Gd/sub 2/CuO/sub 4/, the (001) diffraction patterns often have extra spots at 1/2(110)* or at 1/4(110)* positions. Extra spots are also observed in La/sub 2/CuO/sub 4/ (orthorhombic) but this is probably due to the space group being primitive rather than centered. These observations are discussed in terms of the ordering of oxygen vacancies in the Cu-O planes of the various perovskite structures. 6 figs.

  12. In Situ Foaming of Porous (La <sub>0.6sub> Sr <sub>0.4sub> ) <sub>0.98sub> (Co <sub>0.2sub> Fe <sub>0.8sub> ) O <sub>3−δsub> (LSCF) Cathodes for Solid Oxide Fuel Cell Applications

    SciTech Connect (OSTI)

    Gandavarapu, Sodith; Sabolsky, Edward; Sabolsky, Katarzyna; Gerdes, Kirk

    2015-01-01

    A binder system containing polyurethane precursors was used to in situ foam (direct foam) a (La{sub 0.6}Sr{sub 0.4}){sub 0.98} (Co{sub 0.2} Fe{sub 0.8}) O{sub 3-{#2;delta}} (LSCF) composition for solid oxide fuel cell (SOFC) cathode applications. The relation between in situ foaming parameters on the final microstructure and electrochemical properties was characterized by microscopy and electrochemical impedance spectroscopy (EIS), respectively. The optimal porous cathode architecture was formed with a 70 vol% solids loading within a polymer precursor composition with a volume ratio of 8:4:1 (isocyanate: PEG: surfactant) in a terpineol-based ink vehicle. The resultant microstructure displayed a broad pore size distribution with highly elongated pore structure.

  13. Northern California CO<sub>2sub> Reduction Project

    SciTech Connect (OSTI)

    Hymes, Edward

    2010-06-16

    C6 Resources LLC, a wholly owned subsidiary of Shell Oil Company, worked with the US Department of Energy (DOE) under a Cooperative Agreement to develop the Northern California CO<sub>2sub> Reduction Project. The objective of the Project is to demonstrate the viability of using Carbon Capture and Sequestration (CCS) to reduce existing greenhouse gas emissions from industrial sources on a large-scale. The Project will capture more than 700,000 metric tonnes of CO<sub>2sub> per year, which is currently being vented to the atmosphere from the Shell Martinez Refinery in Contra Costa County. The CO<sub>2sub> will be compressed and dehydrated at the refinery and then transported via pipeline to a sequestration site in a rural area in neighboring Solano County. The CO<sub>2sub> will be sequestered into a deep saline formation (more than two miles underground) and will be monitored to assure secure, long-term containment. The pipeline will be designed to carry as much as 1,400,000 metric tonnes of CO<sub>2sub> per year, so additional capacity will be available to accommodate CO<sub>2sub> captured from other industrial sources. The Project is expected to begin operation in 2015. The Project has two distinct phases. The overall objective of Phase 1 was to develop a fully definitive design basis for the Project. The Cooperative Agreement with the DOE provided cost sharing for Phase 1 and the opportunity to apply for additional DOE cost sharing for Phase 2, comprising the design, construction and operation of the Project. Phase 1 has been completed. DOE co-funding is provided by the American Recovery and Reinvestment Act (ARRA) of 2009. As prescribed by ARRA, the Project will stimulate the local economy by creating manufacturing, transportation, construction, operations, and management jobs while addressing the need to reduce greenhouse gas emissions at an accelerated pace. The Project, which will also assist in meeting the CO<sub>2sub> reduction requirements set forth in California's Climate Change law, presents a major opportunity for both the environment as well as the region. C6 Resources is conducting the Project in collaboration with federally-funded research centers, such as Lawrence Berkeley National Lab and Lawrence Livermore National Lab. C6 Resources and Shell have identified CCS as one of the critical pathways toward a worldwide goal of providing cleaner energy. C6 Resources, in conjunction with the West Coast Regional Carbon Sequestration Partnership (WESTCARB), has conducted an extensive and ongoing public outreach and CCS education program for local, regional and state-wide stakeholders. As part of a long term relationship, C6 Resources will continue to engage directly with community leaders and residents to ensure public input and transparency. This topical report summarizes the technical work from Phase 1 of the Project in the following areas; Surface Facility Preliminary Engineering: summarizes the preliminary engineering work performed for CO<sub>2sub> capture, CO<sub>2sub> compression and dehydration at the refinery, and surface facilities at the sequestration site; Pipeline Preliminary Engineering: summarizes the pipeline routing study and preliminary engineering design; Geologic Sequestration: summarizes the work to characterize, model and evaluate the sequestration site; and Monitoring, Verification and Accounting (MVA): summarizes the MVA plan to assure long-term containment of the sequestered CO<sub>2sub>.

  14. Influence of Yb{sub 2}O{sub 3} on electrical and microstructural

    Office of Scientific and Technical Information (OSTI)

    characteristics of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics (Journal Article) | SciTech Connect Influence of Yb{sub 2}O{sub 3} on electrical and microstructural characteristics of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics Citation Details In-Document Search Title: Influence of Yb{sub 2}O{sub 3} on electrical and microstructural characteristics of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics Graphical abstract: Some Yb atoms entered in the lattice of CCTO substituted the Ca sites, the rest of Yb atoms

  15. Magnetic measurements on ??CS{sub 2}U{sub 4}O{sub 12}

    SciTech Connect (OSTI)

    Kanrar, Buddhadev Misra, N. L.; Sastry, P. U.; Dube, V.; Ravikumar, G.

    2014-04-24

    Magnetic and XRD measurements on ??CS{sub 2}U{sub 4}O{sub 12} having uranium in mixed valent states of U (V) and U (VI) have been made. The study reveals that the compound undergoes an antiferromagnetic transition below 25K and an anomalous magnetic behavior was seen around 75K. This anomalous behavior indicates towards a structural phase transition. However, the low temperature XRD could not confirm this observation.

  16. Correlation between upconversion photoluminescence and dielectric response in Ba-substituted (Sr{sub 1?x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30}

    SciTech Connect (OSTI)

    Wei, T.; Wang, X. D.; Zhao, C. Z.; Liu, M. F.; Liu, J. M.

    2014-06-30

    The filled tetragonal tungsten bronze (Sr{sub 1?x}Ba{sub x}){sub 4}(La{sub 0.85}Ho{sub 0.025}Yb{sub 0.125}){sub 2}Ti{sub 4}Nb{sub 6}O{sub 30} (SBLTNx: Ho-Yb) ceramics with different Ba substitution levels (x) are prepared. The upconversion photoluminescence (UC-PL) and dielectric permittivity are investigated. The substitution of Sr{sup 2+} ions at the A{sub 2}-sites by larger Ba{sup 2+} ions results in substantial variation of the UC-PL intensity as a function of substitution level x. Furthermore, the dielectric response to the substitution of Sr{sup 2+} by Ba{sup 2+} suggests a close correlation between the UC-PL intensity and dielectric permittivity. The origin for this correlation is discussed based on the random stress field (RSF) model.

  17. Method of preparing (CH.sub.3).sub.3 SiNSO and byproducts thereof

    DOE Patents [OSTI]

    Spicer, Leonard D.; Bennett, Dennis W.; Davis, Jon F.

    1984-01-01

    (CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy.

  18. Measurement of the ?<sub>b>? lifetime in the exclusive decay ?<sub>b>??J/??? in pp? collisions at ?s=1.96 TeV

    SciTech Connect (OSTI)

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Aoki, M.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besanon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bose, T.; Brandt, A.; Brandt, O.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Brown, J.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Prez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chakraborty, D.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Chevalier-Thry, S.; Cho, D. K.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Croc, A.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Dliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duggan, D.; Duperrin, A.; Dutt, S.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Facini, G.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garcia-Bellido, A.; Garca-Gonzlez, J. A.; Garca-Guerra, G. A.; Gavrilov, V.; Gay, P.; Geng, W.; Gerbaudo, D.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Goussiou, A.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grnendahl, S.; Grnewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hagopian, S.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hohlfeld, M.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffr, M.; Jayasinghe, A.; Jesik, R.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kaadze, K.; Kajfasz, E.; Karmanov, D.; Kasper, P. A.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kulikov, S.; Kumar, A.; Kupco, A.; Kur?a, T.; Kuzmin, V. A.; Lammers, S.; Landsberg, G.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lellouch, J.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Lubatti, H. J.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaa-Villalba, R.; Malik, S.; Malyshev, V. L.; Maravin, Y.; Martnez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Naimuddin, M.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nunnemann, T.; Obrant, G.; Orduna, J.; Osman, N.; Osta, J.; Padilla, M.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Ptroff, P.; Pleier, M.-A.; Podesta-Lerma, P. L. M.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Rangel, M. S.; Ranjan, K.; Ratoff, P. N.; Razumov, I.; Renkel, P.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Salcido, P.; Snchez-Hernndez, A.; Sanders, M. P.; Sanghi, B.; Santos, A. S.; Savage, G.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schlobohm, S.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Shivpuri, R. K.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Smith, K. J.; Snow, G. R.; Snow, J.; Snyder, S.; Sldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Stutte, L.; Suter, L.; Svoisky, P.; Takahashi, M.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tschann-Grimm, K.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.

    2012-06-07

    We measure the ??<sub>b> lifetime in the fully reconstructed decay ??<sub>b>?J/??? using 10.4 fb? of pp? collisions collected with the D0 detector at ?s=1.96 TeV. The lifetime of the topologically similar decay channel B??J/?K?<sub>S> is also measured. We obtain ?(??<sub>b>)=1.3030.075(stat)0.035(syst) ps and ?(B?)=1.5080.025(stat)0.043(syst) ps. Using these measurements, we determine the lifetime ratio of ?(??<sub>b>)/?(B?)=0.8640.052(stat)0.033(syst).

  19. Crystallographic, electronic, thermal, and magnetic properties of single-crystal SrCo<sub>2sub>As>2sub>

    SciTech Connect (OSTI)

    Pandey, Abhishek; Quirinale, D. G.; Jayasekara, W.; Sapkota, A.; Kim, M. G.; Dhaka, R. S.; Lee, Y.; Heitmann, T. W.; Stephens, P. W.; Ogloblichev, V.; Kreyssig, A.; McQueeney, R. J.; Goldman, A. I.; Kaminski, Adam; Harmon, B. N.; Furukawa, Y.; Johnston, D. C.

    2013-07-01

    In tetragonal SrCo<sub>2sub>As>2 sub>single crystals, inelastic neutron scattering measurements demonstrated that strong stripe-type antiferromagnetic (AFM) correlations occur at a temperature T = 5 K [W. Jayasekara et al., arXiv:1306.5174] that are the same as in the isostructural AFe<sub>2sub>As>2sub> (A = Ca, Sr, Ba) parent compounds of high-T<sub>c> superconductors. This surprising discovery suggests that SrCo<sub>2sub>As>2sub> may also be a good parent compound for high-T<sub>c sub>superconductivity. Here, structural and thermal expansion, electrical resistivity ?, angle-resolved photoemission spectroscopy (ARPES), heat capacity C<sub>p>, magnetic susceptibility ?, 75As NMR and neutron diffraction measurements of SrCo<sub>2sub>As>2sub> crystals are reported together with LDA band structure calculations that shed further light on this fascinating material. The c-axis thermal expansion coefficient ?<sub>c> is negative from 7 to 300 K, whereas ?<sub>a> is positive over this T range. The ?(T) shows metallic character. The ARPES measurements and band theory confirm the metallic character and in addition show the presence of a flat band near the Fermi energy E<sub>F>. The band calculations exhibit an extremely sharp peak in the density of states D(E<sub>F>) arising from a flat d<sub>x2-y2sub> band. A comparison of the Sommerfeld coefficient of the electronic specific heat with ?(T ? 0) suggests the presence of strong ferromagnetic itinerant spin correlations which on the basis of the Stoner criterion predicts that SrCo<sub>2sub>As>2sub> should be an itinerant ferromagnet, in conflict with the magnetization data. The ?(T) does have a large magnitude, but also exhibits a broad maximum at 115 K suggestive of dynamic short-range AFM spin correlations, in agreement with the neutron scattering data. The measurements show no evidence for any type of phase transition between 1.3 and 300 K and we propose that metallic SrCo<sub>2sub>As>2sub> has a gapless quantum spin-liquid ground state.

  20. Branching Fraction and CP Asymmetry Measurements in Inclusive B ? X<sub>s> ???? and B ? X<sub>s>? Decays from BABAR

    SciTech Connect (OSTI)

    Eigen, G.

    2015-04-29

    We present an update on total and partial branching fractions and on CP asymmetries in the semi-inclusive decay B ? X<sub>s>???-. Further, we summarize our results on branching fractions and CP asymmetries for semi-inclusive and fully-inclusive B ? X<sub>s>? decays. We present the first result on the CP asymmetry diff erence of charged and neutral B ? X<sub>s>? decays yielding the first constraint on the ratio of Wilson coeffi cients Im(C<sub>8sub>eff/C>7sub>eff).

  1. Optical response of nongranular high- T sub c Y sub 1 Ba sub 2 Cu sub 3 O sub 7 sub minus x superconducting thin films

    SciTech Connect (OSTI)

    Frenkel, A. ); Saifi, M.A.; Venkatesan, T.; England, P. ); Wu, X.D.; Inam, A. )

    1990-03-15

    We have investigated the optical response of {ital c}-axis oriented crystalline Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7}{sub {minus}{ital x}} thin films (bridge and meander devices) on strontium titanate and MgO substrates. cw optical response to a He-Ne laser radiation (wavelength of 0.63 {mu}m) was primarily bolometric. The pulsed optical response was studied with {ital Q}-switched and mode-locked {ital Q}-switched short pulses from a Nd:YAG laser at the wavelength of 1.06 {mu}m. We identify two distinct components contributing to the pulsed optical response: a nonbolometric (as fast as 1 ns) and a bolometric component (several ns). The bolometric component is strong at temperatures in the vicinity of the transition region to the normal state. The nonbolometric component is dominant at temperatures below the transition region showing weak temperature dependence and a linear dependence on the bias current. These results are discussed using the flux motion model and also electron-phonon scattering relaxation dynamics of nonequilibrium superconductors based on the theory of Bardeen-Cooper-Schrieffer. The results suggest that with proper optimization of device parameters (geometry, critical current density, etc.) sensitive bolometers and high-speed detectors covering a broad electromagnetic spectrum (visible and infrared) may be developed.

  2. Reaction-bonding preparation of Si{sub 3}N{sub 4}/MoSi{sub 2} and Si{sub 3}N{sub 4}/WSi{sub 2} composites from elemental powders

    SciTech Connect (OSTI)

    Zhang, B.R.; Marino, F.

    1997-01-01

    Si{sub 3}N{sub 4}/MoSi{sub 2} and Si{sub 3}N{sub 4}/WSi{sub 2} composites were prepared by reaction-bonding processes using as starting materials powder mixtures of Si-Mo and Si-W, respectively. A presintering step in an Ar-base atmosphere was used before nitriding for the formation of MoSi{sub 2} and WSi{sub 2}; the nitridation in a N{sub 2}-base atmosphere was followed after presintering with the total stepwise cycle of 1,350 C {times} 20 h + 1,400 C {times} 20 h + 1,450 C {times} 2 h. The final phases obtained in the two different composites were Si{sub 3}N{sub 4} and MoSi{sub 2} or WSi{sub 2}; no free elemental Si and Mo or W were detected by X-ray diffraction.

  3. Li{sub 2}B{sub 3}O{sub 4}F{sub 3}, a new lithium-rich fluorooxoborate

    SciTech Connect (OSTI)

    Pilz, Thomas; Nuss, Hanne; Jansen, Martin

    2012-02-15

    The new lithium fluorooxoborate, Li{sub 2}B{sub 3}O{sub 4}F{sub 3}, is obtained by a solid state reaction from LiBO{sub 2} and LiBF{sub 4} at 553 K and crystallizes in the acentric orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} (no. 19) with the cell parameters a=4.8915(9), b=8.734(2), and c=12.301(2) A. Chains of fluorinated boroxine rings along the b axis consists of BO{sub 3} triangles and BO{sub 2}F{sub 2} as well as BO{sub 3}F tetrahedra. Mobile lithium ions are compensating the negative charge of the anionic chain, in which the fourfold coordinated boron atoms bear a negative formal charge. Annealing Li{sub 2}B{sub 3}O{sub 4}F{sub 3} at temperatures above 573 K leads to conversion into Li{sub 2}B{sub 6}O{sub 9}F{sub 2}. The title compound is an ionic conductor with the highest ion conductivity among the hitherto know lithium fluorooxoborates, with conductivities of 1.6 Multiplication-Sign 10{sup -9} and 1.8 Multiplication-Sign 10{sup -8} S cm{sup -1} at 473 and 523 K, respectively. - Graphical abstract: Repetition unit of Li{sub 2}B{sub 3}O{sub 4}F{sub 3}. Highlights: Black-Right-Pointing-Pointer Li{sub 2}B{sub 3}O{sub 4}F{sub 3} is the third member within the family of lithium fluorooxoborates. Black-Right-Pointing-Pointer It shows the highest lithium ion conductivity among them. Black-Right-Pointing-Pointer Chains of interconnected fluorinated boroxine rings run along the b axis. Black-Right-Pointing-Pointer Acentric space group meets the requirement for second harmonic generation.

  4. An in-situ phosphorus source for the synthesis of Cu<sub>3sub>P and the subsequent conversion to Cu<sub>3sub>PS>4sub> nanoparticle clusters

    SciTech Connect (OSTI)

    Sheets, Erik J.; Stach, Eric A.; Yang, Wei -Chang; Balow, Robert B.; Wang, Yunjie; Walker, Bryce C.; Agrawal, Rakesh

    2015-09-20

    The search for alternative earth abundant semiconducting nanocrystals for sustainable energy applications has brought forth the need for nanoscale syntheses beyond bulk synthesis routes. Of particular interest are metal phosphides and derivative I-V-VI chalcogenides including copper phosphide (Cu<sub>3sub>P) and copper thiophosphate (Cu<sub>3sub>PS>4sub>). Herein, we report a one-pot, solution-based synthesis of Cu<sub>3sub>P nanocrystals utilizing an in-situ phosphorus source: phosphorus pentasulfide (P<sub>2sub>S>5sub>) in trioctylphosphine (TOP). By injecting this phosphorus source into a copper solution in oleylamine (OLA), uniform and size controlled Cu<sub>3sub>P nanocrystals with a phosphorous-rich surface are synthesized. The subsequent reaction of the Cu<sub>3sub>P nanocrystals with decomposing thiourea forms nanoscale Cu<sub>3sub>PS>4sub> particles having p-type conductivity and an effective optical band gap of 2.36 eV.

  5. Precipitate size refinement by CeO{sub 2} and Y{sub 2}BaCuO{sub 5} additions in directionally solidified YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect (OSTI)

    Vilalta, N.; Sandiumenge, F.; Pinol, S.; Obradors, X.

    1997-01-01

    Directional solidification of YBa{sub 2}Cu{sub 3}O{sub 7} has been carried out through a Bridgman technique, and the influence of Y{sub 2}BaCuO{sub 5} and CeO{sub 2} additives on the size of Y{sub 2}BaCuO{sub 5} precipitates has been investigated. It is demonstrated in this work that the most efficient procedure to reduce the size of the Y{sub 2}BaCuO{sub 5} precipitates is to increase the concentration of nucleation centers present in the peritectic decomposition of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}. A small concentration (0.3{endash}1 wt.{percent}) of CeO{sub 2} has a strong influence on the solidification process and on the size of Y{sub 2}BaCuO{sub 5} precipitates. It is shown that when CeO{sub 2} is added, further refinement of the size of precipitates results from the formation of nanometric Y{sub 2}O{sub 3} particles which further enhance the multinucleation effect. We have also observed that coarsening effects are avoided with CeO{sub 2} additives. {copyright} {ital 1997 Materials Research Society.}

  6. Mechanistic insight into peroxydisulfate reactivity: Oxidation of the cis,cis-[Ru(bpy)<sub>2sub>(OH>2sub>)]>2sub>O4+ "Blue Dimmer"

    SciTech Connect (OSTI)

    Hurst, James K.; Roemeling, Margo D.; Lymar, Sergei V.

    2015-04-10

    One-electron oxidation of the ?-oxo dimer (cis,cis-[RuIII(bpy)<sub>2sub>(OH>2sub>)]>2sub>O4+, {3,3}) to {3,4} by S<sub>2sub>O>8sub>2- can be described by three concurrent reaction pathways corresponding to the three protic forms of {3,3}. Free energy correlations of the rate constants, transient species dynamics determined by pulse radiolysis, and medium and temperature dependencies of the alkaline pathway all suggest that the rate determining step in these reactions is a strongly non-adiabatic dissociative electron transfer within a precursor ion pair leading to the {3,4}|SO<sub>4sub>2-|SO<sub>4sub>- ion triple. As deduced from the SO<sub>4sub>- scavenging experiments with 2-propanol, the SO<sub>4sub>- radical then either oxidizes {3,4} to {4,4} within the ion triple, effecting a net two-electron oxidation of {3,3}, or escapes in solution with ~25 % probability to react with additional {3,3} and {3,4}, that is, effecting sequential one-electron oxidations. The reaction model presented also invokes rapid {3,3} + {4,4} ? 2{3,4} comproportionation, for which k<sub>com> ~5107 M-1 s-1 was independently measured. The model provides an explanation for the observation that despite favorable energetics, no oxidation beyond the {3,4} state was detected. As a result, the indiscriminate nature of oxidation by SO<sub>4sub>- indicates that its fate must be quantitatively determined when using S<sub>2sub>O>8sub>2- as an oxidant

  7. Low Temperature Propane Oxidation over Co<sub>3sub>O>4sub> based Nano-array Catalysts. Ni Dopant Effect, Reaction Mechanism and Structural Stability

    SciTech Connect (OSTI)

    Ren, Zheng; Wu, Zili; Gao, Puxian; Song, Wenqiao; Xiao, Wen; Guo, Yanbing; Ding, Jun; Suib, Steven L.; Gao, Pu-Xian

    2015-06-09

    Low temperature propane oxidation has been achieved by Co<sub>3sub>O>4sub>-based nano-array catalysts featuring low catalytic materials loading. The Ni doping into the Co<sub>3sub>O>4sub> lattice has led to enhanced reaction kinetics at low temperature by promoting the surface lattice oxygen activity. In situ DRIFTS investigation in tandem with isotopic oxygen exchange reveals that the propane oxidation proceeds via Mars-van Krevelen mechanism where surface lattice oxygen acts as the active site whereas O<sub>2sub> in the reaction feed does not directly participate in CO<sub>2sub> formation. The Ni doping promotes the formation of less stable carbonates on the surface to facilitate the CO<sub>2sub> desorption. The thermal stability of Ni doped Co<sub>3sub>O>4sub> decreases with increased Ni concentration while catalytic activity increases. A balance between enhanced activity and compromised thermal stability shall be considered in the Ni doped Co<sub>3sub>O>4sub> nano-array catalysts for low temperature hydrocarbon oxidation. This study provides useful and timely guidance for rational catalyst design toward low temperature catalytic oxidation.

  8. CuCo<sub>2sub>O>4sub> ORR/OER Bi-functional catalyst: Influence of synthetic approach on performance

    SciTech Connect (OSTI)

    Serov, Alexey; Andersen, Nalin I.; Roy, Aaron J.; Matanovic, Ivana; Artyushkova, Kateryna; Atanassov, Plamen

    2015-02-07

    A series of CuCo<sub>2sub>O>4sub> catalysts were synthesized by pore forming, sol-gel, spray pyrolysis and sacrificial support methods. Catalysts were characterized by XRD, SEM, XPS and BET techniques. The electrochemical activity for the oxygen reduction and oxygen evolution reactions (ORR and OER) was evaluated in alkaline media by RRDE. Density Functional Theory was used to identify two different types of active sites responsible for ORR/OER activity of CuCo<sub>2sub>O>4sub> and it was found that CuCo<sub>2sub>O>4 sub>can activate the O-O bond by binding molecular oxygen in bridging positions between Co or Co and Cu atoms. It was found that the sacrificial support method (SSM) catalyst has the highest performance in both ORR and OER and has the highest content of phase-pure CuCo<sub>2sub>O>4sub>. It was shown that the presence of CuO significantly decreases the activity in oxygen reduction and oxygen evolution reactions. As a result, the half-wave potential (E<sub>1/2sub>) of CuCo<sub>2sub>O>4sub>-SSM was found as 0.8 V, making this material a state-of-the-art, unsupported oxide catalyst.

  9. Itinerant Antiferromagnetism in FeMnP<sub>0.8sub>Si>0.2sub>

    SciTech Connect (OSTI)

    Sales, Brian C.; Susner, Michael A.; Conner, Benjamin S.; Yan, Jiaqiang Q.; May, Andrew F.

    2015-09-25

    Compounds based on the Fe<sub>2sub>P structure have continued to attract interest because of the interplay between itinerant and localized magnetism in a noncentrosymmetric crystal structure, and because of the recent developments of these materials for magnetocaloric applications. We report the growth and characterization of millimeter-sized single crystals of FeMnP<sub>0.8sub>Si>0.2sub> with the Fe<sub>2sub>P structure. Single-crystal x-ray diffraction, magnetization, resistivity, and Hall and heat capacity data are reported. The crystals exhibit itinerant antiferromagnetic order below 158 K with no hint of ferromagnetic behavior in the magnetization curves and with the spins ordered primarily in the ab plane. The room-temperature resistivity is close to the Ioffe-Regel limit for a metal. Single-crystal x-ray diffraction indicates a strong preference for Mn to occupy the larger pyramidal 3g site. The cation site preference in the as-grown crystals and the antiferromagnetism were not changed after high-temperature anneals and a rapid quench to room temperature

  10. SO.sub.2 sensor

    DOE Patents [OSTI]

    Dalla Betta, Ralph A. (Mountain View, CA); Sheridan, David R. (Menlo Park, CA)

    1994-01-01

    This invention is a process for detecting low concentration levels of sulfur oxides (SO.sub.2) in a flowing gas stream (typically a combustion exhaust gas stream) and a catalytic SO.sub.2 sensor system which may be used in that process.

  11. Kondo Physics and Unconventional Superconductivity in the U Intermetallic U<sub>2sub>PtC>2sub> Revealed by NMR

    SciTech Connect (OSTI)

    Mounce, Andrew M.; Thompson, Joe David

    2015-12-17

    The set of slides begins by discussing the topic NMR of heavy fermion superconductors under the topics heavy fermion materials, superconductivity, and nuclear magnetic resonance. The history of these phenomena is sketched, with particular mention made of CeCu<sub>2sub>Si>2sub>, UPt<sub>3sub>, and UBe<sub>13sub>. Unconventional superconductivity, which is non-phonon mediated superconductivity, presents a high T<sub>c> (up to ~150 K), and involves a more complicated spin/orbital wave function. The presentation then goes on to give experimental NMR results for U<sub>2sub>PtC>2sub> and Pu-115’s.

  12. Dopant-Induced Nanoscale Electronic Inhomogeneities in Ca<sub>2-xsub>SrxRuO>4sub>

    SciTech Connect (OSTI)

    Zhang, Jiandi; Ismail, #; Moore, R. G.; Wang, S. -C.; Ding, H.; Jin, Rongying; Mandrus, David; Plummer, E Ward

    2006-01-01

    Ca{sub 2-x}Sr{sub x}RuO{sub 4} single crystals with 0.1 {le} x {le} 2.0 have been studied systematically using scanning tunneling microscopy (STM) and spectroscopy, low-energy electron diffraction, and angle resolved photoelectron spectroscopy (ARPES). In contrast with the well-ordered lattice structure, the local density of states at the surface clearly shows a strong doping dependent nanoscale electronic inhomogeneity, regardless of the fact of isovalent substitution. Remarkably, the surface electronic roughness measured by STM and the inverse spectral weight of quasiparticle states determined by ARPES are found to vary with x in the same manner as the bulk in-plane residual resistivity, following the Nordheim rule. For the first time, the surface measurements - especially those with STM - are shown to be in good agreement with the bulk transport results, all clearly indicating a doping-induced electronic disorder in the system.

  13. Hydrothermal crystallization of Na{sub 2}Ti{sub 6}O{sub 13}, Na{sub 2}Ti{sub 3}O{sub 7}, and Na{sub 16}Ti{sub 10}O{sub 28} in the NaOH-TiO{sub 2}-H{sub 2}O system at a temperature of 500 deg. C and a pressure of 0.1 GPa: The structural mechanism of self-assembly of titanates from suprapolyhedral clusters

    SciTech Connect (OSTI)

    Hyushin, G. D.

    2006-07-15

    An increase in the NaOH concentration in the NaOH-TiO{sub 2} (rutile)-H{sub 2}O system at a temperature of 500 deg. C and a pressure of 0.1 GPa leads to the crystallization R-TiO{sub 2} + Na{sub 2}Ti{sub 6}O{sub 13} {sup {yields}} Na{sub 2}Ti{sub 3}O{sub 7} {sup {yields}} Na{sub 16}Ti{sub 10}O{sub 28}. Crystals of the Na{sub 2}Ti{sub 6}O{sub 13} titanate (space group C2/m) have the three-dimensional framework structure Ti{sub 6}O{sub 13}. The structure of the Na{sub 2}Ti{sub 3}O{sub 7} titanate (space group P2{sub 1}/m) contains the two-dimensional layers Ti{sub 3}O{sub 7}. The structure of the Na{sub 16}Ti{sub 10}O{sub 28} titanate (space group P-1) is composed of the isolated ten-polyhedron cluster precursors Ti{sub 10}O{sub 28}. In all the structures, the titanium atoms have an octahedral coordination (MTiO{sub 6}). The matrix self-assembly of the Na{sub 2}Ti{sub 6}O{sub 13} and Na{sub 2}Ti{sub 3}O{sub 7} (Na{sub 4}Ti{sub 6}O{sub 14}) crystal structures from Na{sub 4}M{sub 12} invariant precursors is modeled. These precursors are clusters consisting of twelve M polyhedra linked through the edges. It is demonstrated that the structurally rigid precursors Na{sub 4}M{sub 12} control all processes of the subsequent evolution of the crystal-forming titanate clusters. The specific features of the self-assembly of the Na{sub 2}Ti{sub 3}O{sub 7} structure that result from the additional incorporation of twice the number of sodium atoms into the composition of the high-level clusters are considered.

  14. Bifunctional Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+}nanocomposites obtained by the homogeneous precipitation method

    SciTech Connect (OSTI)

    Peng, Hongxia; Cui, Bin; Wang, Yingsai

    2013-05-15

    Graphical abstract: The TEM images reveal clearly the coreshell structures because of the obvious difference in contrast between the central part and the fringe, which indicates the Gd{sub 2}O{sub 3}:Eu{sup 3+} layer had successfully deposited on the magnetite Fe{sub 3}O{sub 4} cores. And Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanoparticles keep the spherical morphology, non-aggregation and rough surface. The images reveal that the average diameters of the Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanoparticles are ?200 nm and ?250 nm, respectively. The thickness of Gd{sub 2}O{sub 3}:Eu{sup 3+} layer is ?25 nm. Highlights: ? Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanocomposites were synthesized by homogeneous precipitation method. ? Formation of coreshell nanostructure revealed by transmission electron microscopy. ? Fe{sub 3}O{sub 4}@Gd{sub 2}O{sub 3}:Eu{sup 3+} nanocomposites showed magnetic behavior and fluorescence properties. ? Possible applications including bioseparation, drug delivery system, bio-labels, etc. - Abstract: An easy homogeneous precipitation method was developed for the synthesis of bifunctional magnetic-fluorescent nanocomposites with Fe{sub 3}O{sub 4} nanoparticles as the core and europium-doped gadolinium oxide (Gd{sub 2}O{sub 3}:Eu{sup 3+}) as the shell. The nanocomposites showed both strong magnetic behavior and unique Eu-related fluorescence properties with a high emission intensity, which may lead to development of nanocomposites with great potential for applications in drug targeting, biosensors, and diagnostic analysis.

  15. Crystal structure of Sr{sub 3}Ir{sub 2}O{sub 7} investigated by

    Office of Scientific and Technical Information (OSTI)

    transmission electron microscopy (Journal Article) | SciTech Connect structure of Sr{sub 3}Ir{sub 2}O{sub 7} investigated by transmission electron microscopy Citation Details In-Document Search Title: Crystal structure of Sr{sub 3}Ir{sub 2}O{sub 7} investigated by transmission electron microscopy We report on the crystallographic structure of the layered perovskite iridate Sr{sub 3}Ir{sub 2}O{sub 7}, investigated using transmission electron microscopy. The space group was found to be Bbcb

  16. Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single

    Office of Scientific and Technical Information (OSTI)

    crystal (Journal Article) | SciTech Connect Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single crystal Citation Details In-Document Search Title: Anisotropic magnetic properties of Dy{sub 6}Cr{sub 4}Al{sub 43} single crystal We have studied the anisotropic magnetic behavior of the rare earth intermetallic compound Dy{sub 6}Cr{sub 4}Al{sub 43}. This compound crystallizes in the hexagonal symmetry and orders ferromagnetically at 8.3 K as confirmed by the magnetic

  17. Investigating the reversibility of structural modifications of Li<sub>xsub>Ni<sub>yMnzCo>1-y-zsub>O₂ cathode materials during initial charge/discharge, at multiple length scales

    SciTech Connect (OSTI)

    Hwang, Sooyeon; Bak, Seong -Min; Kim, Seung Min; Chung, Kyung Yoon; Chang, Wonyoung

    2015-08-11

    In this work, we investigate the structural modifications occurring at the bulk, subsurface, and surface scales of Li<sub>xsub>Ni<sub>yMnzCo>1-y-zsub>O₂ (NMC; y, z = 0.8, 0.1 and 0.4, 0.3, respectively) cathode materials during the initial charge/discharge. Various analytical tools, such as X-ray diffraction, selected-area electron diffraction, electron energy-loss spectroscopy, and high-resolution electron microscopy, are used to examine the structural properties of the NMC cathode materials at the three different scales. Cut-off voltages of 4.3 and 4.8 V are applied during the electrochemical tests as the normal and extreme conditions, respectively. The high-Ni-content NMC cathode materials exhibit unusual behaviors, which is deviate from the general redox reactions during the charge or discharge. The transition metal (TM) ions in the high-Ni-content NMC cathode materials, which are mostly Ni ions, are reduced at 4.8 V, even though TMs are usually oxidized to maintain charge neutrality upon the removal of Li. It was found that any changes in the crystallographic and electronic structures are mostly reversible down to the sub-surface scale, despite the unexpected reduction of Ni ions. However, after the discharge, traces of the phase transitions remain at the edges of the NMC cathode materials at the scale of a few nanometers (i.e., surface scale). This study demonstrates that the structural modifications in NMC cathode materials are induced by charge as well as discharge at multiple length scales. These changes are nearly reversible after the first cycle, except at the edges of the samples, which should be avoided because these highly localized changes can initiate battery degradation.

  18. High-G testing of MEMS mechanical non-volatile memory and silicon re-entry

    Office of Scientific and Technical Information (OSTI)

    switch. (Technical Report) | SciTech Connect Technical Report: High-G testing of MEMS mechanical non-volatile memory and silicon re-entry switch. Citation Details In-Document Search Title: High-G testing of MEMS mechanical non-volatile memory and silicon re-entry switch. Two different Sandia MEMS devices have been tested in a high-g environment to determine their performance and survivability. The first test was performed using a drop-table to produce a peak acceleration load of 1792 g's

  19. Volatiles combustion in fluidized beds. [Quarterly] technical progress report, 4 December 1994--4 March 1995

    SciTech Connect (OSTI)

    Pendergrass II, R.A.; Mansker, L.D.; Hesketh, R.P.

    1995-08-01

    The goal of this project is to investigate the conditions in which volatiles will bum within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization are being conducted to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. The work conducted during the period 4 December, 1994 through, 3 March 1995 is presented in this technical progress report. The research consists of the application of a detailed chemical kinetics model for propane combustion and planned improvements in the experimental system.

  20. Volatiles combustion in fluidized beds. Technical progress report, 4 March 1993--3 June 1993

    SciTech Connect (OSTI)

    Hesketh, R.P.

    1993-09-01

    The goal of this project is to investigate the conditions in which volatiles will burn within both the dense and freeboard regions of fluidized beds. Experiments using a fluidized bed operated at incipient fluidization will be performed to characterize the effect of particle surface area, initial fuel concentration, and particle type on the inhibition of volatiles within a fluidized bed. The work conducted during the period 4 March, 1993 through 3 June, 1993 is reported in this technical progress report. The work during this time period consists primarily of the startup and trouble shooting of the fluidized bed reactor and gas phase modeling of methane and propane.

  1. Thermal engine driven heat pump for recovery of volatile organic compounds

    DOE Patents [OSTI]

    Drake, Richard L.

    1991-01-01

    The present invention relates to a method and apparatus for separating volatile organic compounds from a stream of process gas. An internal combustion engine drives a plurality of refrigeration systems, an electrical generator and an air compressor. The exhaust of the internal combustion engine drives an inert gas subsystem and a heater for the gas. A water jacket captures waste heat from the internal combustion engine and drives a second heater for the gas and possibly an additional refrigeration system for the supply of chilled water. The refrigeration systems mechanically driven by the internal combustion engine effect the precipitation of volatile organic compounds from the stream of gas.

  2. Method For Removing Volatile Components From A Gel-Cast Ceramic Article

    DOE Patents [OSTI]

    Klug, Frederic Joseph; DeCarr, Sylvia Marie

    2004-09-07

    A method of removing substantially all of the volatile component in a green, volatile-containing ceramic article is disclosed. The method comprises freezing the ceramic article; and then subjecting the frozen article to a vacuum for a sufficient time to freeze-dry the article. Frequently, the article is heated while being freeze-dried. Use of this method efficiently reduces the propensity for any warpage of the article. The article is often formed from a ceramic slurry in a gel-casting process. A method for fabricating a ceramic core used in investment casting is also described.

  3. Method for removing volatile components from a ceramic article, and related processes

    DOE Patents [OSTI]

    Klug, Frederic Joseph; DeCarr, Sylvia Marie

    2002-01-01

    A method of removing substantially all of the volatile component in a green, volatile-containing ceramic article is disclosed. The method comprises freezing the ceramic article; and then subjecting the frozen article to a vacuum for a sufficient time to freeze-dry the article. Frequently, the article is heated while being freeze-dried. Use of this method efficiently reduces the propensity for any warpage of the article. The article is often formed from a ceramic slurry in a gel-casting process. A method for fabricating a ceramic core used in investment casting is also described.

  4. Influence of Sn on the thermoelectric properties of (Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals

    SciTech Connect (OSTI)

    Kulbachinskii, V.A.; Kytin, V.G.; Kudryashov, A.A.; Lunin, R.A.

    2012-09-15

    The influence of tin on the thermoelectric properties of p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals (x=0; 0.25; 0.5) has been investigated. The temperature dependence of the Seebeck coefficient S, the electrical conductivity {sigma}, the heat conductivity k and the thermoelectric figure of merit of p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals were measured in the temperature range 7-300 K. By an increase the Sn content, the hole concentration increases in p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3}. The heat conductivity k of the p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} crystals decreases due to the Sn doping, while the electrical conductivity {sigma} increases in the temperature interval about 200sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals (x=0; 0.25; 0.5) has been investigated. Temperature dependence of Seebeck coefficient S, electrical conductivity {sigma}, thermal conductivity k and figure of merit of p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} single crystals were measured in the temperature range 7-300 K. Electrical conductivity increases in the temperature interval 150Ksub x}Sb{sub 1-x}){sub 2}Te{sub 3} as shown in figure. By increasing the Sn content, the hole concentration increases in p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3}. The thermal conductivity k of the p-(Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} crystals decreases due to Sn doping. The Seebeck coefficient S for all compositions is positive and decreases due to Sn doping in the whole temperature range due to increase of the hole concentration under Sn doping. Highlights: Black-Right-Pointing-Pointer thermoelectric figure of merit for p-(Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} investigated at 7-300 K. Black-Right-Pointing-Pointer preferential scattering is ionized impurity scattering in Sn doped samples. Black-Right-Pointing-Pointer electrical conductivity increases at 150 Ksub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} with Sn doping. Black-Right-Pointing-Pointer the thermal conductivity of (Bi{sub x}Sb{sub 1-x}){sub 2-y}Sn{sub y}Te{sub 3} decreases due to Sn doping.

  5. UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/: non-metallic isotypes of superconducting LaFe/sub 4/P/sub 12/

    SciTech Connect (OSTI)

    Meisner, G.P.; Torikachvili, M.S.; Yang, K.N.; Maple, M.B.; Guertin, R.P.

    1984-01-01

    The new compound UFe/sub 4/P/sub 12/, which was found to be isostructural to superconducting LaFe/sub 4/P/sub 12/ and with a lattive constant of 7.7729 A, is a semiconductor and shows ferromagnetic order below 3.15 K. CeFe/sub 4/P/sub 12/ is also a semiconductor and its magnetic susceptibility is unusually small in comparison to LaFe/sub 4/P/sub 12/. The semiconducting behaviors of both UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/ seem anomalous and may arise from strong f-electron hybridization.

  6. UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/: Nonmetallic isotypes of superconducting LaFe/sub 4/P/sub 12/

    SciTech Connect (OSTI)

    Meisner, G.P.; Torikachvili, M.S.; Yang, K.N.; Maple, M.B.; Guertin, R.P.

    1985-04-15

    The new compound UFe/sub 4/P/sub 12/, which was found to be isostructural to superconducting LaFe/sub 4/P/sub 12/ and have a lattice constant of 7.7729 A, is a semiconductor and shows ferromagnetic order below 3.15 K. CeFe/sub 4/P/sub 12/ is also a semiconductor, and its magnetic susceptibility is unusually small in comparison to LaFe/sub 4/P/sub 12/. The semiconducting behaviors of both UFe/sub 4/P/sub 12/ and CeFe/sub 4/P/sub 12/ seem anomalous and may arise from strong f-electron hybridization.

  7. Phase diagram and magnetocaloric effects in Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15} and (Mn{sub 1?x}Cr{sub x})NiGe{sub 1.05} alloys

    SciTech Connect (OSTI)

    Quetz, Abdiel Muchharla, Baleeswaraiah; Dubenko, Igor; Talapatra, Saikat; Ali, Naushad; Samanta, Tapas; Stadler, Shane

    2014-05-07

    The magnetocaloric and thermomagnetic properties of Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15} and (Mn{sub 1?x}Cr{sub x}) NiGe{sub 1.05} systems for 0???x???0.105 and 0???x???0.1, respectively, have been studied by x-ray diffraction, differential scanning calorimetry, and magnetization measurements. Partial substitution of Cr for Mn in (Mn{sub 1?x}Cr{sub x})NiGe{sub 1.05} results in a first order magnetostructural transition from a hexagonal paramagnetic to an orthorhombic paramagnetic phase near T{sub M}???380?K (for x?=?0.07). Partial substitution of Cr for In in Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15} shifts the magnetostructural transition to a higher temperature (T?=?T{sub M}???450?K) for x?=?0.1. Large magnetic entropy changes of ?S?=??12 (J/(kgK)) and ?S?=??11 (J/(kgK)), both for a magnetic field change of 5?T, were observed in the vicinity of T{sub M} for (Mn{sub 1?x}Cr{sub x})NiGe{sub 1.05} and Ni{sub 50}Mn{sub 35}(In{sub 1?x}Cr{sub x}){sub 15}, respectively.

  8. Eliminating Voltage Decay of Lithium-Rich Li<sub>1.14sub>Mn>0.54sub>Ni>0.14sub>Co>0.14sub>O>2sub> Cathodes by Controlling the Electrochemical Process

    SciTech Connect (OSTI)

    Wei, Z.; Zhu, Y.; Zhang, W.; Wang, F.; Zhang, Q.; Qiu, B.; Han, S.; Xia, Y.; Liu, Z.

    2015-03-27

    Lithium-rich material owns a particularly high capacity owing to the activation of electrochemical inactive Li<sub>2sub>MnO>3sub> phase. But at the same time, MnO<sub>2sub> phase formed after Li<sub>2sub>MnO>3sub> activation confronts a severe problem of converting to spinel phase, and resulting in voltage decay. To our knowledge, this phenomenon is inherent property of layered manganese oxide materials and can hardly be overcome. Based on this, unlike previous reports, herein we design a method for the first time to accelerate the phase transformation by tuning the charge upper-limit voltage at a high value, so the phase transformation process can be finished in a few cycles. Then material structure remains stable while cycling at a low upper-limit voltage. By this novel method voltage decay is eliminated significantly.

  9. Field-dependent magnetization of BiFeO<sub>3sub> in ultrathin La<sub>0.7sub>Sr>0.3sub>MnO>3sub>/BiFeO>3sub> superlattice

    SciTech Connect (OSTI)

    Fitzsimmons, Michael R.; Jia, Quanxi X.; Singh, Surendra; Chen, A. P.; Xiong, J.

    2015-12-02

    We report the observation of field-induced magnetization of BiFeO<sub>3sub> (BFO) in an ultrathin La<sub>0.7sub>Sr>0.3sub>MnO>3sub> (LSMO)/BFO superlattice using polarized neutron reflectivity (PNR). The depth dependent structure and magnetic characterization of subnano layer thick (thickness ~ 0.7 nm each) LSMO/BFO hetrostructure is carried out using X-ray reflectivity and PNR techniques. Our PNR results indicate parallel alignment of magnetization as well as enhancement in magnetic moment across LSMO/BFO interfaces. The study showed an increase in average magnetization on increasing applied magnetic field at 10K. As a result, we observed a saturation magnetization of 110 ± 15 kA/m (~0.8 μ<sub>B>/Fe) for ultrathin BFO layer (~2 unit cell) sandwiched between ultrathin LSMO layers (~ 2 unit cell).

  10. Simple and low-temperature preparation of Co{sub 3}O{sub 4} sphere-like nanoparticles via solid-state thermolysis of the [Co(NH{sub 3}){sub 6}](NO{sub 3}){sub 3} complex

    SciTech Connect (OSTI)

    Farhadi, Saeid; Pourzare, Kolsoum

    2012-06-15

    Highlights: ? [Co(NH{sub 3}){sub 6}](NO{sub 3}){sub 3} precursor was used for synthesizing pure Co{sub 3}O{sub 4} nanocrystals. ? Co{sub 3}O{sub 4} nanocrystals were synthesized at low temperature of 200 C. ? Co{sub 3}O{sub 4} nanocrystals show a weak ferromagnetic behavior at room temperature. ? This simple method is low-cost and suitable for high-scale production of Co{sub 3}O{sub 4}. -- Abstract: In this work, spinel-type Co{sub 3}O{sub 4} spherical nanoparticles were easily prepared via decomposition of the hexamminecobalt(III) nitrate complex, [Co(NH{sub 3}){sub 6}](NO{sub 3}){sub 3}, at low temperature (200 C). The product was characterized by thermal analysis (TGA/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, UVvis spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), BrunauerEmmettTeller (BET) specific surface area measurement and magnetic measurements. The results confirmed that pure single-phase Co{sub 3}O{sub 4} nanoparticles with weak ferromagnetic behavior were obtained by this method. TEM images showed that the Co{sub 3}O{sub 4} nanoparticles are sphere-like with an average diameter size of around 15 nm. The optical spectrum indicated two direct band gaps at 2.15 and 3.56 eV which are blue-shifted relative to reported values for the bulk sample. Using this fast and simple method, Co{sub 3}O{sub 4} nanoparticles can be produced without expensive and toxic solvents or complicated equipment.

  11. A novel organic–inorganic hybrid with Anderson type polyanions as building blocks: (C{sub 6}H{sub 10}N{sub 3}O{sub 2}){sub 2}Na(H{sub 2}O){sub 2}[Al(OH){sub 6}Mo{sub 6}O{sub 18}]·6H{sub 2}O

    SciTech Connect (OSTI)

    Thabet, Safa; Ayed, Brahim; Haddad, Amor

    2012-11-15

    Graphical abstract: Display Omitted Highlights: ► Synthesis of a novel inorganic–organic hybrid compound based on Anderson polyoxomolybdates. ► Characterization by X-ray diffraction, IR and UV–Vis spectroscopies of the new compound. ► Potential applications in catalysis, biochemical analysis and electrical conductivity of the organic–inorganic compound. -- Abstract: A new organic–inorganic hybrid compound based on Anderson polyoxomolybdates, (C{sub 6}H{sub 10}N{sub 3}O{sub 2}){sub 2}Na(H{sub 2}O){sub 2}[Al(OH){sub 6}Mo{sub 6}O{sub 18}]·6H{sub 2}O (1) have been isolated by the conventional solution method and characterized by single-crystal X-ray diffraction, infrared, ultraviolet spectroscopy and Thermogravimetric Analysis (TGA). This compound crystallized in the triclinic system, space group P−1, with a = 94.635(1) Å, b = 10.958(1) Å, c = 11.602(1) Å, α = 67.525(1)°, β = 71.049(1)°, γ = 70.124(1)° and Z = 1. The crystal structures of the compounds exhibit three-dimensional supramolecular assembly based on the extensive hydrogen bonding interactions between organic cations, sodium cations, water molecules and Anderson polyoxoanions. The infrared spectrum fully confirms the X-ray crystal structure and the UV spectrum of the title compound exhibits an absorption peak at 210 nm.

  12. Electron-hole diffusion lengths >175 μm in solution-grown CH<sub>3sub>NH>3sub>PbI>3sub> single crystals

    SciTech Connect (OSTI)

    Dong, Qingfeng; Fang, Yanjun; Shao, Yuchuan; Mulligan, Padhraic; Qiu, Jie; Cao, Lei; Huang, Jinsong

    2015-02-27

    Long, balanced electron and hole diffusion lengths greater than 100 nanometers in the polycrystalline organolead trihalide compound CH<sub>3sub>NH>3sub>PbI>3sub> are critical for highly efficient perovskite solar cells. We found that the diffusion lengths in CH<sub>3sub>NH>3sub>PbI>3sub> single crystals grown by a solution-growth method can exceed 175 micrometers under 1 sun (100 mW cm–2) illumination and exceed 3 millimeters under weak light for both electrons and holes. The internal quantum efficiencies approach 100% in 3-millimeter-thick single-crystal perovskite solar cells under weak light. These long diffusion lengths result from greater carrier mobility, longer lifetime, and much smaller trap densities in the single crystals than in polycrystalline thin films. As a result, the long carrier diffusion lengths enabled the use of CH<sub>3sub>NH>3sub>PbI>3sub> in radiation sensing and energy harvesting through the gammavoltaic effect, with an efficiency of 3.9% measured with an intense cesium-137 source.

  13. Kondo Lattice Behavior in the Ordered Dilute Magnetic Semiconductor Yb<sub>14-xsub>LaxMnSb>11sub>

    SciTech Connect (OSTI)

    Sales, Brian C; Khalifah, Peter; Enck, Thomas P; Nagler, Evan J; Sykora, Richard E; Jin, Rongying; Mandrus, David

    2005-01-01

    We report Hall, magnetic, heat capacity, and doping studies from single crystals of Yb{sub 14}MnSb{sub 11} and Yb{sub 13.3}La{sub 0.7}MnSb{sub 11}. These heavily doped semiconducting compounds are ferromagnetic below 53 and 39 K, respectively. The renormalization of the carrier mass from 2m{sub 3} near room temperature to 20m{sub e} at 5 K, plus the magnetic evidence for partial screening of the Mn magnetic moments suggest that these compounds represent rare examples of an underscreened Kondo lattice with T{sub K} {approx} 285 K.

  14. Λ<sub>b→pl⁻ν¯l> form factors from lattice QCD with static b quarks

    SciTech Connect (OSTI)

    Detmold, William; Lin, C.-J. David; Meinel, Stefan; Wingate, Matthew

    2013-07-23

    We present a lattice QCD calculation of form factors for the decay Λ<sub>bsub>→pμ⁻ν¯μ>, which is a promising channel for determining the Cabibbo-Kobayashi-Maskawa matrix element |V<sub>ub>| at the Large Hadron Collider. In this initial study we work in the limit of static b quarks, where the number of independent form factors reduces to two. We use dynamical domain-wall fermions for the light quarks, and perform the calculation at two different lattice spacings and at multiple values of the light-quark masses in a single large volume. Using our form factor results, we calculate the Λ<sub>bsub>→pμ⁻ν¯μ> differential decay rate in the range 14 GeV²≤q²≤q²<sub>max>, and obtain the integral ∫q²<sub>max> <sub>14 GeV²sub>[dΓ/dq²]dq²/|V<sub>ub>|²=15.3±4.2 ps⁻¹. Combined with future experimental data, this will give a novel determination of |V<sub>ub>| with about 15% theoretical uncertainty. The uncertainty is dominated by the use of the static approximation for the b quark, and can be reduced further by performing the lattice calculation with a more sophisticated heavy-quark action.

  15. Visible Light Photoreduction of CO<sub>2sub> Using CdSe/Pt/TiO<sub>2sub> Heterostructured Catalysts

    SciTech Connect (OSTI)

    Wang, Congjun; Thompson, Robert L.; Baltrus, John; Matranga, Christopher

    2010-01-07

    A series of CdSe quantum dot (QD)-sensitized TiO<sub>2sub> heterostructures have been synthesized, characterized, and tested for the photocatalytic reduction of CO<sub>2sub> in the presence of H<sub>2sub>O. Our results show that these heterostructuredmaterials are capable of catalyzing the photoreduction of CO<sub>2sub> using visible light illumination (? > 420 nm) only. The effect of removing surfactant caps from the CdSe QDs by annealing and using a hydrazine chemical treatment have also been investigated. The photocatalytic reduction process is followed using infrared spectroscopy to probe the gas-phase reactants and gas chromatography to detect the products. Gas chromatographic analysis shows that the primary reaction product is CH<sub>4sub>, with CH<sub>3sub>OH, H<sub>2sub>, and CO observed as secondary products. Typical yields of the gas-phase products after visible light illumination (? > 420 nm) were 48 ppm g-1 h-1 of CH<sub>4sub>, 3.3 ppm g-1 h-1 of CH<sub>3sub>OH (vapor), and trace amounts of CO and H<sub>2.sub>

  16. Exchange bias effect in Au-Fe<sub>3sub>O>4sub> dumbbell nanoparticles induced by the charge transfer from gold

    SciTech Connect (OSTI)

    Feygenson, Mikhail; Bauer, John C; Gai, Zheng; Marques, Carlos; Aronson, Meigan C.; Teng, Xiaowei; Su, Dong; Stanic, Vesna; Urban, Volker S; Kevin, Beyer; Dai, Sheng

    2015-08-10

    We have studied the origin of the exchange bias effect in the Au-Fe<sub>3sub>O>4sub> dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe<sub>3sub>O>4sub> nanoparticles (9.8 nm). The magnetization, small-angle neutron scattering, synchrotron x-ray diffraction and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wstite phase within Fe<sub>3sub>O>4sub> nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe<sub>3sub>O>4sub> is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe<sub>3sub>O>4sub> into FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed across the interface to accommodate an excess of oxygen released during the reduction of magnetite.

  17. Ionic Liquids: Breakthrough Absorption Technology for Post-Combustion CO{sub 2} Capture

    SciTech Connect (OSTI)

    Maginn, Edward

    2012-09-30

    This is the final report for DE-FC26-07NT43091 “Ionic Liquids: Breakthrough Absorption Technology for Post-Combustion CO{sub 2} Capture”. A detailed summary is provided of the ionic liquid (IL) discovery process, synthesis and testing results, process / systems modeling, lab-scale operational testing, corrosion testing and commercialization possibilities. The work resulted in the discovery of a new class of ionic liquids (ILs) that efficiently react with CO{sub 2} in a 1:1 stoichiometry with no water present and no increase in viscosity. The enthalpy of reaction was tuned to optimize process economics. The IL was found to have excellent corrosion behavior with and without CO{sub 2} present. In lab-scale tests, the IL was able to effectively remove CO{sub 2} from a simulated flue gas stream, although mass transfer was slower than with aqueous monoethanolamine (MEA) due to higher viscosities. The non-volatile nature of the solvent and its high thermal stability, however, make it an intriguing option. An independent systems analysis indicates that the economics of using the best IL discovered to date (NDIL0157), are at least comparable to – and potentially slightly better than -– the Fluor Econamine FG PlusTM process (DOE Case 12). Further work should be directed at improving mass transfer / lowering viscosity and developing commercial synthesis routes to make these ILs at scale in an inexpensive manner. Demonstration of the process at larger scales is also warranted, as is the exploration of other process configurations that leverage the anhydrous nature of the solvent and its extremely low volatility.

  18. Hydrogenation of CO<sub>2sub> to methanol: Importance of metal–oxide and metal–carbide interfaces in the activation of CO<sub>2sub>

    SciTech Connect (OSTI)

    Rodriguez, José A.; Liu, Ping; Stacchiola, Dario J.; Senanayake, Sanjaya D.; White, Michael G.; Chen, Jingguang G.

    2015-09-30

    In this study, the high thermochemical stability of CO<sub>2sub> makes it very difficult to achieve the catalytic conversion of the molecule into alcohols or other hydrocarbon compounds, which can be used as fuels or the starting point for the generation of fine chemicals. Pure metals and bimetallic systems used for the CO<sub>2sub> → CH<sub>3sub>OH conversion usually bind CO<sub>2sub> too weakly and, thus, show low catalytic activity. Here, we discuss a series of recent studies that illustrate the advantages of metal–oxide and metal–carbide interfaces when aiming at the conversion of CO2 into methanol. CeO<sub>x>/Cu(111), Cu/CeO<sub>x/TiO>2sub>(110), and Au/CeO<sub>x/TiO>2sub>(110) exhibit an activity for the CO<sub>2sub> → CH<sub>3sub>OH conversion that is 2–3 orders of magnitude higher than that of a benchmark Cu(111) catalyst. In the Cu–ceria and Au–ceria interfaces, the multifunctional combination of metal and oxide centers leads to complementary chemical properties that open active reaction pathways for methanol synthesis. Efficient catalysts are also generated after depositing Cu and Au on TiC(001). In these cases, strong metal–support interactions modify the electronic properties of the admetals and make them active for the binding of CO<sub>2sub> and its subsequent transformation into CH<sub>3sub>OH at the metal–carbide interfaces.

  19. Millimeter size single crystals of superconducting YBa[sub 2]Cu[sub 3]O[sub x

    DOE Patents [OSTI]

    Damento, M.A.; Gschneidner, K.A. Jr.

    1989-04-25

    A method of growing large, up to 1 mm size single crystals of superconducting YBa[sub 2]Cu[sub 3]O[sub x], wherein x equals from 6.5 to 7.2 is disclosed.

  20. The equilibrium vortex melting transition in YBa{sub 2}Cu{sub 3}O{sub 7}

    SciTech Connect (OSTI)

    Crabtree, G.W.; Welp, U.; Kwok, W.K.; Fendrich, J.A.; Veal, B.W.

    1996-10-01

    The dynamic and thermodynamic experimental evidence supporting first order vortex melting in clean crystals of YBa{sub 2}Cu{sub 3}O{sub 7} is reviewed.

  1. Phonon and magnon scattering of Bi{sub 2}Fe{sub 4}O{sub 9} ceramic

    SciTech Connect (OSTI)

    Sharma, Poorva E-mail: vdinesh33@rediffmail.com; Kumar, Ashwini E-mail: vdinesh33@rediffmail.com; Varshney, Dinesh E-mail: vdinesh33@rediffmail.com

    2014-04-24

    We report the phonon structure of Bi{sub 2}Fe{sub 4}O{sub 9} ceramics as synthesized by solid-state reaction route. Rietveld refined X-ray diffraction patterns confirmed the formation of single-phase perovskite structure and all the peaks of Bi{sub 2}Fe{sub 4}O{sub 9} perfectly indexed to the orthorhombic (space group Pbam). Raman scattering measurements identifies 12A{sub g}+1B{sub 2g}+1B{sub 3g} Raman active optical phonon modes. Apart from phonon scattering, mode at 470 cm{sup ?1} is observed which is due to magnon scattering. The P-E loop infers paraelectric nature of Bi{sub 2}Fe{sub 4}O{sub 9}.

  2. Millimeter size single crystals of superconducting YBa.sub.2 Cu.sub.3 O.sub .

    DOE Patents [OSTI]

    Damento, Michael A. (Ames, IA); Gschneidner, Jr., Karl A. (Ames, IA)

    1989-04-25

    A method of growing large, up to 1 mm size single crystals of superconducting YBa.sub.2 Cu.sub.3 O.sub.x, wherein x equals from 6.5 to 7.2.

  3. Synthesis, crystal structure and magnetic properties of Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}

    SciTech Connect (OSTI)

    Kokal, I.; Aydemir, U.; Prots, Yu.; Frster, T.; Sichelschmidt, J.; Yahyaoglu, M.; Auffermann, G.; Schnelle, W.; Schappacher, F.; Pttgen, R.; Somer, M.

    2014-02-15

    Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] was synthesized from the metathesis reaction of Li{sub 3}[BN{sub 2}] and EuCl{sub 3} at 850 C. Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] crystallizes in the trigonal space group R3{sup }c (No. 167) with a=12.0225(2) , c=6.8556(2) and Z=6. In the crystal structure, isolated, planar cyclic [B{sub 3}N{sub 6}]{sup 9?} units are charge-balanced by the mixed-valence Eu{sup 3+}/Eu{sup 2+} and Li{sup +} cations. Li{sup +} occupies partially (44%) the Wyckoff site 6b and is sandwiched between the [B{sub 3}N{sub 6}]{sup 9?} anions. Mssbauer spectroscopy results show the resonance lines of Eu{sup 2+} and Eu{sup 3+}, respectively, indicating the heterogeneous mixed valency of the Eu atoms. X-Band ESR investigations between 5 and 300 K reveal an intense signal over the whole temperature range originating from Eu{sup 2+}. Magnetic susceptibility measurements indicate a CurieWeiss behavior with an experimental effective magnetic moment of ?{sub eff}=8.28 ?{sub B} per formula unit. - Graphical abstract: Single crystals of Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] was obtained from the metathesis reaction of Li{sub 3}[BN{sub 2}] and EuCl{sub 3.}{sup 151}Eu Mssbauer, ESR and magnetic susceptibility measurements reveal the heterogeneous mixed valency of the Eu atoms. Display Omitted - Highlights: Single crystals of Li{sub 0.44}Eu{sub 3}[B{sub 3}N{sub 6}] was obtained from the metathesis reaction of Li{sub 3}[BN{sub 2}] and EuCl{sub 3} at 850 C. Crystal structure is built up by isolated, planar cyclic [B{sub 3}N{sub 6}]{sup 9?} units which are surrounded by mixed valence Eu{sup 3+}/Eu{sup 2+}. Li{sup +} occupies partially (44%) the site 6b and is sandwiched between the [B{sub 3}N{sub 6}]{sup 9?} anions. The {sup 151}Eu Mssbauer spectroscopy, electron spin resonance spectroscopy and magnetic susceptibility measurements confirm the heterogeneous mixed valency of Eu.

  4. Synthesis, characterization and optical properties of NH{sub 4}Dy(PO{sub 3}){sub 4}

    SciTech Connect (OSTI)

    Chemingui, S.; Ferhi, M. Horchani-Naifer, K.; Férid, M.

    2014-09-15

    Polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} polyphosphate have been grown by the flux method. This compound was found to be isotopic with NH{sub 4}Ce(PO{sub 3}){sub 4} and RbHo(PO{sub 3}){sub 4}. It crystallizes in the monoclinic space group P2{sub 1/n} with unit cell parameters a=10.474(6) Å, b=9.011(4) Å, c=10.947(7) Å and β=106.64(3)°. The title compound has been transformed to triphosphate Dy(PO{sub 3}){sub 3} after calcination at 800 °C. Powder X-ray diffraction, infrared and Raman spectroscopies and the differential thermal analysis have been used to identify these materials. The spectroscopic properties have been investigated through absorption, excitation, emission spectra and decay curves of Dy{sup 3+} ion in both compounds at room temperature. The emission spectra show the characteristic emission bands of Dy{sup 3+} in the two compounds, before and after calcination. The integrated emission intensity ratios of the yellow to blue (I{sub Y}/I{sub B}) transitions and the chromaticity properties have been determined from emission spectra. The decay curves are found to be double-exponential. The non-exponential behavior of the decay rates was related to the resonant energy transfer as well as cross-relaxation between the donor and acceptor Dy{sup 3+} ions. The determined properties have been discussed as function of crystal structure of both compounds. They reveal that NH{sub 4}Dy(PO{sub 3}){sub 4} is promising for white light generation but Dy(PO{sub 3}){sub 3} is potential candidates in field emission display (FED) and plasma display panel (PDP) devices. - Graphical abstract: The CIE color coordinate diagrams showing the chromatic coordinates of Dy{sup 3+} luminescence in NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3}. - Highlights: • The polycrystalline powders of NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3} are synthesized. • The obtained powders are characterized. • The spectroscopic properties of Dy{sup 3+} ion are investigated. • Results are discussed as function of crystal structure and chemical composition. • The usefulness of NH{sub 4}Dy(PO{sub 3}){sub 4} and Dy(PO{sub 3}){sub 3} in optical devices is revealed.

  5. Palladium site ordering and the occurrence of superconductivity in Bi{sub 2}Pd{sub 3}Se{sub 2-x}S{sub x}

    SciTech Connect (OSTI)

    Weihrich, R.; Matar, S.F.; Anusca, I.; Pielnhofer, F.; Peter, P.; Bachhuber, F.; Eyert, V.

    2011-04-15

    The crystallographic and electronic structures of compounds related to parkerite (Bi{sub 2}Ni{sub 3}S{sub 2}) are investigated with respect to the recently reported occurrence (Bi{sub 2}Pd{sub 3}Se{sub 2}) and absence (Bi{sub 2}Pd{sub 3}S{sub 2}) of superconductivity. Similarities and differences of the crystal structures are discussed within the series of solid solutions Bi{sub 2}Pd{sub 3}S{sub 2-x}Se{sub x} from powder and single crystal diffraction data. From crystal structure refinements, the question of different structures and settings of parkerite is discussed. Similar and different 2D and 3D partial Pd-Ch (Ch=S, Se) structures are related to half antiperovskite ordering schemes. To investigate the relation of low dimensional structures and the occurrence of superconductivity, electronic structures are analyzed by scalar-relativistic DFT calculations, including site projected DOS, ECOV and Fermi surfaces. -- Graphical abstract: Structure relations for perovskite type BiPd{sub 3}C, BiPd{sub 3/2}Se and BiPd{sub 3/2}S. Display Omitted Research highlights: {yields} Merging crystallographic and electronic structures studies to understand chalcogenides related to parkerite (Bi{sub 2}Ni{sub 3}S{sub 2}). {yields} Investigation in view of recently reported occurrence (Bi{sub 2}Pd{sub 3}Se{sub 2}) and absence (Bi{sub 2}Pd{sub 3}S{sub 2}) of superconductivity. {yields} Relationship of half perovskites with perovskites.

  6. PARTICULATE CHARACTERIZATION AND ULTRA LOW-NOx BURNER FOR THE CONTROL OF NO{sub x} AND PM{sub 2.5} FOR COAL FIRED BOILERS

    SciTech Connect (OSTI)

    Ralph Bailey; Hamid Sarv; Jim Warchol; Debi Yurchison

    2001-09-30

    In response to the serious challenge facing coal-fired electric utilities with regards to curbing their NO{sub x} and fine particulate emissions, Babcock and Wilcox and McDermott Technology, Inc. conducted a project entitled, ''Particulate Characterization and Ultra Low-NO{sub x} Burner for the Control of NO{sub x} and PM{sub 2.5} for Coal Fired Boilers.'' The project included pilot-scale demonstration and characterization of technologies for removal of NO{sub x} and primary PM{sub 2.5} emissions. Burner development and PM{sub 2.5} characterization efforts were based on utilizing innovative concepts in combination with sound scientific and fundamental engineering principles and a state-of-the-art test facility. Approximately 1540 metric tonnes (1700 tons) of high-volatile Ohio bituminous coal were fired. Particulate sampling for PM{sub 2.5} emissions characterization was conducted in conjunction with burner testing. Based on modeling recommendations, a prototype ultra low-NO{sub x} burner was fabricated and tested at 100 million Btu/hr in the Babcock and Wilcox Clean Environment Development Facility. Firing the unstaged burner with a high-volatile bituminous Pittsburgh 8 coal at 100 million Btu/hr and 17% excess air achieved a NO{sub x} goal of 0.20 lb NO{sub 2}/million Btu with a fly ash loss on ignition (LOI) of 3.19% and burner pressure drop of 4.7 in H{sub 2}O for staged combustion. With the burner stoichiometry set at 0.88 and the overall combustion stoichiometry at 1.17, average NO{sub x} and LOI values were 0.14 lb NO{sub 2}/million Btu and 4.64% respectively. The burner was also tested with a high-volatile Mahoning 7 coal. Based on the results of this work, commercial demonstration is being pursued. Size classified fly ash samples representative of commercial low-NO{sub x} and ultra low-NO{sub x} combustion of Pittsburgh 8 coal were collected at the inlet and outlet of an ESP. The mass of size classified fly ash at the ESP outlet was sufficient to evaluate the particle size distribution, but was of insufficient size to permit reliable chemical analysis. The size classified fly ash from the inlet of the ESP was used for detailed chemical analyses. Chemical analyses of the fly ash samples from the ESP outlet using a high volume sampler were performed for comparison to the size classified results at the inlet. For all test conditions the particulate removal efficiency of the ESP exceeded 99.3% and emissions were less than the NSPS limits of {approx}48 mg/dscm. With constant combustion conditions, the removal efficiency of the ESP increased as the ESP voltage and Specific Collection Area (SCA) increased. The associated decrease in particle emissions occurred in size fractions both larger and smaller than 2.5 microns. For constant ESP voltage and SCA, the removal efficiency for the ultra low-NO{sub x} combustion ash (99.4-99.6%) was only slightly less than for the low-NO{sub x} combustion ash (99.7%). The decrease in removal efficiency was accompanied by a decrease in ESP current. The emission of PM{sub 2.5} from the ESP did not change significantly as a result of the change in combustion conditions. Most of the increase in emissions was in the size fraction greater than 2.5 microns, indicating particle re-entrainment. These results may be specific to the coal tested in this program. In general, the concentration of inorganic elements and trace species in the fly ash at the ESP inlet was dependent on the particle size fraction. The smallest particles tended to have higher concentrations of inorganic elements/trace species than larger particles. The concentration of most elements by particle size range was independent of combustion condition and the concentration of soluble ions in the fly ash showed little change with combustion condition when evaluated on a carbon free basis.

  7. Kinetics of coal combustion: Part 2, Mechanisms and kinetics of coal volatiles combustion

    SciTech Connect (OSTI)

    Essenhigh, R.H.; Bailey, E.G.; Shaw, D.W. )

    1988-12-01

    Values of global kinetic constants for the combustion of coal volatiles have been determined for the first time for volatiles from three coals (two bituminous coals and a Texas lignite). Global kinetic constants for methane and propane were also measured in the same apparatus to allow comparison with reference gases. Comparisons have also been made with values of global kinetics for pure hydrocarbons from a range of experiments as found in the literature. The volatiles were pyrolyzed from crushed coal drawn on weighed trays through a gas-fired muffle furnace, and they were burned at the top of a tube in an intense back-mix volume treated theoretically as a stirred reactor. Two types of experiment were carried out: partial combustion measurements near the stoichiometric for all coals from which the global kinetics were determined; and extinction limits for the Pittsburgh {number sign}8 coal volatiles to determine the extinction loop. The near stoichiometric generated kinetic data were used to predict the extinction limits with substantial agreement. Extinction loops for methane, propane and carbon monoxide were also measured for comparison.

  8. Volatile organic compound emissions from usaf wastewater treatment plants in ozone nonattainment areas. Master's thesis

    SciTech Connect (OSTI)

    Ouellette, B.A.

    1994-09-01

    In accordance with the 1990 Clean Air Act Amendments (CAAA), this research conducts an evaluation of the potential emission of volatile organic compounds (VOCs) from selected Air Force wastewater treatment plants. Using a conservative mass balance analysis and process specific simulation models, volatile organic emission estimates are calculated for four individual facilities--Edwards AFB, Luke AFB, McGuire AFB, and McClellan AFB--which represent a cross section of the current inventory of USAF wastewater plants in ozone nonattainment areas. From these calculations, maximum facility emissions are determined which represent the upper limit for the potential VOC emissions from these wastewater plants. Based on the calculated emission estimates, each selected wastewater facility is evaluated as a potential major stationary source of volatile organic emissions under both Title I of the 1990 CAAA and the plant's governing Clean Air Act state implementation plan. Next, the potential impact of the specific volatile organics being emitted is discussed in terms of their relative reactivity and individual contribution to tropospheric ozone formation. Finally, a relative comparison is made between the estimated VOC emissions for the selected wastewater facilities and the total VOC emissions for their respective host installations.

  9. Structural and superconducting properties of La{sub 2{minus}x}R{sub

    Office of Scientific and Technical Information (OSTI)

    x}Ba{sub 2}Ca{sub y}Cu{sub 4+y}O{sub 10+{delta}} (R=Nd,Gd;y=2x) system (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Structural and superconducting properties of La{sub 2{minus}x}R{sub x}Ba{sub 2}Ca{sub y}Cu{sub 4+y}O{sub 10+{delta}} (R=Nd,Gd;y=2x) system Citation Details In-Document Search Title: Structural and superconducting properties of La{sub 2{minus}x}R{sub x}Ba{sub 2}Ca{sub y}Cu{sub 4+y}O{sub 10+{delta}} (R=Nd,Gd;y=2x) system A nonsuperconducting

  10. Downhole fluid injection systems, CO<sub>2sub> sequestration methods, and hydrocarbon material recovery methods

    DOE Patents [OSTI]

    Schaef, Herbert T.; McGrail, B. Peter

    2015-07-28

    Downhole fluid injection systems are provided that can include a first well extending into a geological formation, and a fluid injector assembly located within the well. The fluid injector assembly can be configured to inject a liquid CO<sub>2sub>/H>2sub>O-emulsion into the surrounding geological formation. CO<sub>2sub> sequestration methods are provided that can include exposing a geological formation to a liquid CO<sub>2sub>/H>2sub>O-emulsion to sequester at least a portion of the CO<sub>2sub> from the emulsion within the formation. Hydrocarbon material recovery methods are provided that can include exposing a liquid CO<sub>2sub>/H>2sub>O-emulsion to a geological formation having the hydrocarbon material therein. The methods can include recovering at least a portion of the hydrocarbon material from the formation.

  11. Method for preparation of textured YBa.sub.2 Cu.sub.3 O.sub.x superconductor

    DOE Patents [OSTI]

    Selvamanickam, Venkat; Goyal, Amit; Kroeger, Donald M.

    1998-01-01

    The present invention relate to textured YBa.sub.2 Cu.sub.3 O.sub.x (Y-123) superconductors and a process of preparing them by directional recrystallization of compacts fabricated from quenched YBCO powders at temperatures about 100.degree. C. below the peritectic temperature to provide a superconductor where more than 75% of the YBa.sub.2 Cu.sub.3 O.sub.x phase is obtained without any Y.sub.2 BaCuO.sub.5 .

  12. Structure, magnetism, specific heat, and dielectric properties of Eu{sub 2}Ta{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Kolodiazhnyi, T. Sakurai, H.; Matsushita, Y.

    2014-11-17

    Polycrystalline Eu{sub 2}Ta{sub 2}O{sub 7} containing layered perovskite slabs was prepared and analyzed. Eu{sub 2}Ta{sub 2}O{sub 7} crystallizes in the orthorhombic centrosymmetric Cmcm space group (with unit cell: a?=?3.95156(9), b?=?27.0775(6), and c?=?5.68279(13) ) isomorphous with high-temperature Sr{sub 2}Ta{sub 2}O{sub 7}. Dielectric measurements reveal that, in contrast to Sr{sub 2}Ta{sub 2}O{sub 7} which is ferroelectric below 166?K, Eu{sub 2}Ta{sub 2}O{sub 7} remains paraelectric down to at least 0.45?K and shows no magneto-dielectric coupling. Magnetic data in the 2400?K range indicate an antiferromagnetic phase transition with a sharp susceptibility peak at 2.71(5) K. Further analysis using specific heat measurements reveals that the second magnetic phase transition occurs at 1.10(5) K and dominates the spin entropy of the Eu{sup 2+} 4f{sup 7} ions. The possible origin of the two successive magnetic phase transitions in Eu{sub 2}Ta{sub 2}O{sub 7} requires further studies.

  13. Quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}

    SciTech Connect (OSTI)

    Kitada, A.; Tsujimoto, Y.; Yamamoto, T. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Kobayashi, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Narumi, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Institute for Materials Research, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Kindo, K. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Aczel, A.A.; Luke, G.M. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Uemura, Y.J. [Department of Physics, Columbia University, New York, NY 10027 (United States); Kiuchi, Y.; Ueda, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Yoshimura, K. [Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Ajiro, Y. [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Kageyama, H., E-mail: kage@scl.kyoto-u.ac.jp [Department of Energy and Hydrocarbon Chemistry, Faculty of Engineering, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan); Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

    2012-01-15

    We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13}. Through a topotactic ion-exchange reaction with CuCl{sub 2}, the precursor RbCa{sub 2}NaNb{sub 4}O{sub 13} presumably having an incoherent octahederal tliting changes into (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} with a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73232(5) A, c=39.2156(4) A). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl{sub 4}O{sub 2} octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov Prime s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} synthesized through a topotactic ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: Black-Right-Pointing-Pointer (CuCl)Ca{sub 2}NaNb{sub 4}O{sub 13} was prepared by ion-exchange reaction of RbCa{sub 2}NaNb{sub 4}O{sub 13} with CuCl{sub 2}. Black-Right-Pointing-Pointer Compound has a 2a{sub p} Multiplication-Sign 2a{sub p} Multiplication-Sign 2c{sub p} superstructure (tetragonal; a=7.73 A, c=39.21 A). Black-Right-Pointing-Pointer Such a well-defined superstructure was not observed in the precursor compound. Black-Right-Pointing-Pointer Aleksandrov Prime s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). Black-Right-Pointing-Pointer Magnetic studies revealed the absence of magnetic order down to 2 K.

  14. CO.sub.2 laser

    DOE Patents [OSTI]

    Rink, John P.

    1977-01-01

    The disclosure relates to a pulsed gas laser comprising an optical resonant cavity, a CO.sub.2 lasing medium, structure for containing the CO.sub.2 lasing medium within the optical cavity and a device for causing a population inversion in the lasing medium, with a novel improvement comprising structure for causing a laser pulse comprising a wavelength in the near 14 .mu.m and near 16 .mu.m range. The structure for cooling the CO.sub.2 lasing medium to less than about -40.degree. C as well is a structure for pumping the maximum inversion of CO.sub.2 molecules within the lasing medium by minimizing the population in the 010 level.

  15. Advanced Sub-Metering Program

    Broader source: Energy.gov [DOE]

    The program is designed to provide information about energy usage for each residences at a multi-residential buildings. Residences living in multi-residential buildings that are not sub-metered d...

  16. THE CHEMICAL COMPOSITION OF CO-RICH COMET C/2009 P1 (GARRADD) AT R{sub h} = 2.4 and 2.0 AU BEFORE PERIHELION

    SciTech Connect (OSTI)

    Paganini, L.; Mumma, M. J.; Villanueva, G. L.; DiSanti, M. A.; Bonev, B. P.; Lippi, M.; Boehnhardt, H.

    2012-03-20

    We quantified 10 parent volatiles in comet C/2009 P1 (Garradd) before perihelion, through high-dispersion infrared spectra acquired with CRIRES at ESO's Very Large Telescope on UT 2011 August 7 (R{sub h} = 2.4 AU) and September 17-21 (R{sub h} = 2.0 AU). On August 7, water was searched for but not detected at an upper limit (3{sigma}) of 2.1 Multiplication-Sign 10{sup 28} s{sup -1}, while ethane was detected with a production rate of 6.1 Multiplication-Sign 10{sup 26} s{sup -1}. On September 17-21, the mean production rate for water was 8.4 Multiplication-Sign 10{sup 28} s{sup -1}, and five trace species (CO, C{sub 2}H{sub 6}, CH{sub 4}, HCN, and CH, OH) were securely detected, and (3{sigma}) upper limits were retrieved for NH{sub 3}, C{sub 2}H{sub 2}, OCS, and HDO. Given the relatively large heliocentric distance, we explored the effect of water not being fully sublimated within our field of view and identified the 'missing' water fraction needed to reconcile the retrieved abundance ratios with the mean values found for 'organics-normal' comets. The individual spatial profiles of parent volatiles and the continuum displayed rather asymmetric outgassing. Indications of H{sub 2}O and CO gas being released in different directions suggest chemically distinct active vents and/or the possible existence of polar and apolar ice aggregates in the nucleus. The high fractional abundance of CO identifies comet C/2009 P1 as a CO-rich comet.

  17. Development of interatomic potentials appropriate for simulation of devitrification of Al<sub>90sub>Sm>10sub> alloy

    SciTech Connect (OSTI)

    Mendelev, M. I.; Zhang, F.; Ye, Z.; Sun, Y.; Nguyen, M. C.; Wilson, S. R.; Wang, C. Z.; Ho, K. M.

    2015-04-23

    In this study, a semi-empirical potential for the Al<sub>90sub>Sm>10sub> alloy is presented. The potential provides satisfactory reproduction of pure Al properties, the formation energies of a set of Al–Sm crystal phases with Sm content about 10%, and the structure of the liquid Al<sub>90sub>Sm>10sub> alloy. During molecular dynamics simulation in which the liquid alloy is cooled at a rate of 1010 K/s, the developed potential produces a glass structure with lower ab initio energy than that produced by ab initio molecular dynamics (AIMD) itself using a typical AIMD cooling rate of 8 ∙1013 K/s. Based on these facts the developed potential should be suitable for simulations of phase transformations in the Al<sub>90sub>Sm>10sub> alloy.

  18. Disorder from order among anisotropic next-nearest-neighbor Ising spin chains in SrHo<sub>2sub>O>4sub>

    SciTech Connect (OSTI)

    Wen, J. -J.; Tian, W.; Garlea, V. O.; Koohpayeh, S. M.; McQueen, T. M.; Li, H. -F.; Yan, J. -Q.; Rodriguez-Rivera, J. A.; Vaknin, D.; Broholm, C. L.

    2015-02-26

    In this study, we describe why Ising spin chains with competing interactions in SrHo<sub>2sub>O>4sub> segregate into ordered and disordered ensembles at low temperatures (T). Using elastic neutron scattering, magnetization, and specific heat measurements, the two distinct spin chains are inferred to have Nel (????) and double-Nel (????) ground states, respectively. Below T<sub>N> = 0.68(2)K, the Nel chains develop three-dimensional long range order (LRO), which arrests further thermal equilibration of the double-Nel chains so they remain in a disordered incommensurate state for T below T<sub>S> = 0.52(2)K. SrHo<sub>2sub>O>4sub> distills an important feature of incommensurate low dimensional magnetism: kinetically trapped topological defects in a quasiddimensional spin system can preclude order in d + 1 dimensions.

  19. Enhanced ferromagnetic order in Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} featuring canted [MnO{sub 4}]{sub ∞} spin chains of mixed-valent Mn(III)/Mn(IV). Aliovalent substitution of the Sr{sub 4−x}Ln{sub x}Mn{sup III}{sub 2+x}Mn{sup IV}{sub 1−x}O{sub 3}(GeO{sub 4}){sub 3} solid-solution

    SciTech Connect (OSTI)

    West, J. Palmer; Sulejmanovic, Dino; Becht, Gregory; He, Jian; Hitchcock, Dale; Yan, Yonggao; Hwu, Shiou-Jyh

    2013-10-15

    Crystals of Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0; x∼0.15 for Ln=La, Pr, Nd, Sm. Eu, Gd, Dy; x∼0.3 for Ln=Gd) were isolated upon using high-temperature, solid-state methods in molten-salt media. These compounds are isostructural with the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} (Ln=La, Sm, Gd) series that contains the same [MnO{sub 4}]{sub ∞} spin chains. The synthesis of the Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} (x=0) phase was carried out by a double aliovalent substitution with respect to the Sr{sup 2+} and Ge{sup 4+} ions that replace Na{sup +}/Ln{sup 3+} and As{sup 5+} in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, respectively. The title series contains mixed-valent Mn(III)/Mn(IV) and shows a limited range of solid solution, both of which were not observed in the previously reported Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series. To form the Sr{sub 4−x}Ln{sub x}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} solid solution, one of the Sr{sup 2+} sites, i.e., the original Ln-site in Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}, is partially substituted by Ln{sup 3+} in a statistical disorder of Sr{sub 1−x}/Ln{sub x}. Initial magnetic investigations of selected derivatives reveal higher ferromagnetic ordering temperatures than those reported for the Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3} series, presumably attributed to a lesser degree of canting as a result of introducing non-Jahn–Teller Mn{sup 4+} ions. Also intriguing is the observation of multiple anomalies at low temperatures which appear to be of electronic origins. - Graphical abstract: Sr{sub 4−x}Ln{sub x}Mn(III){sub 2+x}Mn(IV){sub 1−x}O{sub 3}(GeO{sub 4}){sub 3}. Display Omitted - Highlights: • Double aliovalent substitution: Sr{sub 4}Mn{sub 3}O{sub 3}(GeO{sub 4}){sub 3} with respect to Na{sub 3}LnMn{sub 3}O{sub 3}(AsO{sub 4}){sub 3}. • Solid solution with respect to statistical disorder of Sr{sub 1−x}Ln{sub x} in one of the two Sr sites. • Mn{sup 3+}/Mn{sup 4+} magnetic ions are spatially arranged in a triangular kagomé fashion. • Enhanced ferromagnetic ordering attributed to doping non-Jahn–Teller Mn{sup 4+}.

  20. Ti{sub 5}O{sub 5} superstructures of cubic titanium monoxide

    SciTech Connect (OSTI)

    Gusev, A. I.

    2013-08-15

    A cubic model is proposed for the Ti{sub 5}O{sub 5} (Ti{sub 5} Black-Small-Square O{sub 5}{open_square} {identical_to} Ti{sub 90} Black-Small-Square {sub 18}O{sub 90}{open_square}{sub 18}) superstructure of nonstoichiometric titanium monoxide Ti{sub x}O{sub z} with double imperfection. The unit cell of the cubic Ti{sub 5}O{sub 5} superstructure has the threefold lattice parameter of the unit cell of the basis disordered B1 structure of Ti{sub x}O{sub z} monoxide and belongs to space group Pm 3-bar m . The channel of the disorder-order transition, i.e., Ti{sub x}O{sub z} (space group Fm 3-bar m)-Ti{sub 5}O{sub 5} (space group Pm 3-bar m), includes 75 superstructure vectors of seven stars (k{sub 10}), (k{sub 7}), (k{sub 6(1)}), (k{sub 6(2)}), (k{sub 4(1)}), (k{sub 4(2)}), and (k{sub 1}). The distribution functions of Ti and O atoms over the sites of the cubic Ti{sub 5}O{sub 5} superstructure are calculated. A comparison of the X-ray and electron diffraction data obtained for ordered TiO{sub 1.087} monoxide with the theoretical simulation results supports the existence of the cubic Ti{sub 5}O{sub 5} superstructure. The cubic (space group Pm 3-bar m) Ti{sub 5}O{sub 5} superstructure is shown to be a high-temperature structure relative to the well-known monoclinic (space group C2/m) superstructure of the same type.

  1. Synthetic CO.sub.2 acceptor

    DOE Patents [OSTI]

    Lancet, Michael S.; Curran, George P.

    1981-08-18

    A synthetic CO.sub.2 acceptor consisting essentially of at least one compound selected from the group consisting of calcium oxide and calcium carbonate supported in a refractory carrier matrix, the carrier having the general formula Ca.sub.5 (SiO.sub.4).sub.2 CO.sub.3. A method for producing the synthetic CO.sub.2 acceptor is also disclosed.

  2. Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3}

    Office of Scientific and Technical Information (OSTI)

    and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} (Journal Article) | SciTech Connect Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} Citation Details In-Document Search Title: Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} have been investigated

  3. Energy efficient microwave synthesis of mesoporous Ce<sub>0.5sub>M>0.5sub>O>2sub> (Ti, Zr, Hf) nanoparticles for low temperature CO oxidation in an ionic liquid – a comparative study

    SciTech Connect (OSTI)

    Alammar, Tarek; Chow, Ying -Kit; Mudring, Anja -Verena

    2014-11-19

    Ce<sub>0.5sub>M>0.5sub>O>2sub> (M = Ti, Zr, Hf) nanoparticles have been successfully synthesized by microwave irradiation in the ionic liquid [C<sub>4sub>mim][Tf>2sub>N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide). The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N<sub>2sub>–adsorption measurements. XRD and Raman spectroscopy analyses confirmed the formation of solid solutions with cubic fluorite structure. The catalytic activities of the Ce<sub>0.5sub>M>0.5sub>O>2sub> (M = Ti, Zr, Hf) nanoparticles were investigated in the low-temperature oxidation of CO. Ce<sub>0.5sub>Zr>0.5sub>O>2sub> nanospheres exhibit the best performance (100% conversion at 350 °C), followed by Ce<sub>0.5sub>Hf>0.5sub>O>2sub> (55% conversion at 360 °C) and Ce<sub>0.5sub>Ti>0.5sub>O>2sub> (11% conversion at 350 °C). Heating the as-prepared Ce<sub>0.5sub>Zr>0.5sub>O>2sub> to 600 °C for extended time leads to a decrease in surface area and, as expected decreased catalytic activity. Depending on the ionic liquid the obtained Ce<sub>0.5sub>Zr>0.5sub>O>2sub> exhibits different morphologies, varying from nano-spheres in [C<sub>4sub>mim][Tf>2sub>N] and [P<sub>66614sub>][Tf>2sub>N] (P<sub>66614sub> = trishexyltetradecylphosphonium) to sheet-like assemblies in [C<sub>3sub>mimOH][Tf>2sub>N] (C<sub>3sub>mimOH = 1-(3-hydroxypropyl)-3-methylimidazolium). As a result, the microwave synthesis superiority to other heating methods like sonochemical synthesis and conventional heating was proven by comparative experiments where the catalytic activity of Ce<sub>0.5sub>Zr>0.5sub>O>2sub> obtained by alternate methods such as conventional heating was found to be poorer than that of the microwave-synthesised material.

  4. Magnetic field induced anisotropy of 139La spin-lattice relaxation rates in stripe ordered La<sub>1.875sub>Ba>0.125sub>CuO>4sub>

    SciTech Connect (OSTI)

    S. -H. Baek; Gu, G. D.; Utz, Y.; Hucker, M.; Buchner, B.; Grafe, H. -J.

    2015-10-26

    We report 139La nuclear magnetic resonance studies performed on a La<sub>1.875sub>Ba>0.125sub>CuO>4sub> single crystal. The data show that the structural phase transitions (high-temperature tetragonal → low-temperature orthorhombic → low-temperature tetragonal phase) are of the displacive type in this material. The 139La spin-lattice relaxation rate T–1<sub>1sub> sharply upturns at the charge-ordering temperature T<sub>CO> = 54 K, indicating that charge order triggers the slowing down of spin fluctuations. Detailed temperature and field dependencies of the T–1<sub>1sub> below the spin-ordering temperature T<sub>SO>=40 K reveal the development of enhanced spin fluctuations in the spin-ordered state for H ∥ [001], which are completely suppressed for large fields along the CuO<sub>2sub> planes. Lastly, our results shed light on the unusual spin fluctuations in the charge and spin stripe ordered lanthanum cuprates.

  5. Cobalt-doped Bi{sub 26}Mo{sub 10}O{sub 69}: Crystal structure and conductivity

    SciTech Connect (OSTI)

    Mikhailovskaya, Z.A.; Buyanova, E.S.; Petrova, S.A.; Morozova, M.V.; Zhukovskiy, V.M.; Zakharov, R.G.; Tarakina, N.V.; Berger, I.F.

    2013-08-15

    A series of cobalt-doped bismuth molybdates were synthesized and investigated using X-ray powder diffraction, transmission electron microscopy and impedance spectroscopy. The ranges of solid solution were determined. Two new compounds, Bi{sub 1?x}Co{sub x}[Bi{sub 12}O{sub 14}]Mo{sub 5}O{sub 34.5?} (x=0.2) and Bi[Bi{sub 12}O{sub 14}]Mo{sub 5?y}Co{sub y}O{sub 34.5?} (y=0.2), which crystallise in monoclinic unit cells have been examined in detail by diffraction methods. Impedance spectroscopy measurements show that the studied materials are good ionic conductors with conductivity values about 510{sup ?3} Scm{sup ?1} at 973 K and 1.710{sup ?4} Scm{sup ?1} at 623 K, which are similar to conductivity values of yttrium substituted zirconia and (YSZ) gadolinium doped ceria (CGO). - Graphical abstract: Measured and calculated diffraction spectra for Bi{sub 12.8}Co{sub 0.2}Mo{sub 5}O{sub 34?} and projection of the Bi{sub 12.8}Co{sub 0.2}Mo{sub 5}O{sub 34?} crystal structure onto the ac plane. Highlights: The limit of the Bi{sub 1?x}Co{sub x}[Bi{sub 12}O{sub 14}]Mo{sub 5}O{sub 34.5?} homogeneity range is equal to x=0.2. The limit of the Bi[Bi{sub 12}O{sub 14}]Mo{sub 5?y}Co{sub y}O{sub 34.5?} homogeneity range is equal to y=0.2. Solid solutions have monoclinic symmetry. No phase transition is observed. The conductivity at 700 for y=0.2 solid solutions is equal to ?lg ?, Scm{sup ?1}=2.23. The conductivity at 350 for y=0.2 solid solutions is equal to ?lg ?, Scm{sup ?1}=3.74.

  6. NO{sub x} reduction RACT compliance requires careful technology selection

    SciTech Connect (OSTI)

    Heckler, G.B.

    1996-05-01

    After the Clean Air Act Amendments passed in 1990, Title I (Attainment and Maintenance of Ambient Air Quality Standards) and Title IV (Acid Deposition Control) of the Act required power plants to submit and implement compliance plans for NO{sub x} and volatile organic compounds (VOC) emissions, among other pollutants. This legislation affected PECO Energy Co.`s Eddystone Generating Station, requiring the utility to comply with the Act under reasonably available control technology (RACT) rules established by the state of Pennsylvania. After carefully considering alternatives aligned with the RACT rules for Pennsylvania, PECO adopted a compliance strategy and submitted it to the Pennsylvania Department of Environmental Protection (PaDEP) for review and approval. Under the case-by-case RACT proposals, the proposed NO{sub x} reduction technology for Units 3 and 4 was to rehabilitate existing OFA ports which had been bricked over. Each of the four corners of these units was originally constructed with an OFA port located in the boiler side walls. Also under the case-by-case RACT proposals, the proposed NO{sub x} reduction technology for the A, B and C auxiliary boilers was to install low-NO{sub x} burners. Under presumptive RACT proposals, PECO proposed low-NO{sub x} burners with close-coupled OFA (CCOFA) and separated OFA (SOFA) as the proposed NO{sub x}-reduction technology for Units 1 and 2. For the combustion turbines PECO proposed to reduce NO{sub x} by limiting the annual capacity factor to 5 percent or less on a 12-month rolling basis. After considering technological and economic feasibility, the utility proposed no VOC reductions because none of the available VOC reduction technologies fell within RACT guidelines.

  7. Synthesis, structural and electrical properties of [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2}

    SciTech Connect (OSTI)

    Karoui, Sahel; Kamoun, Slaheddine; Jouini, Amor

    2013-01-15

    Synthesis, structural and electrical properties are given for a new organic stannous pseudo halide material. The structure of the [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2} reveals that the adjacent Sn(II) centres are bridged by a pair of SCN{sup -} anions to form a 1-D array giving rise to the anionic chains (SnCl(NCS){sub 2}){sub n}{sup n-}. These chains are themselves interconnected by means of N-H Horizontal-Ellipsis Cl(S) hydrogen bonds originating from the organic cation [(NH{sub 3}){sub 2}(CH{sub 2}){sub 2}]{sup 2+}. The AC impedance measurements were performed as a function of both frequency and temperature. The electrical conduction and dielectric relaxation have been studied. The activation energy associated with the electrical relaxation determined from the electric modulus spectra was found close to that of the activation energy obtained for DC conductivity. The conduction mechanisms are attributed to the quantum mechanical tunneling model in phase I and to the proton hopping among hydrogen vacancies in phase II. - Graphical abstract: Atomic coordination in [C2H10N2][SnCl(NCS)2)2]. Highlights: Black-Right-Pointing-Pointer X-ray diffraction analysis shows the 1D network character of the structure. Black-Right-Pointing-Pointer DSC experiments show a phase transition at 336 K. Black-Right-Pointing-Pointer The AC conductivity is interpreted in terms of Jonsher's law. Black-Right-Pointing-Pointer Two conduction mechanisms are proposed for phase I and II.

  8. Sulfur dioxide gas detection with Na/sub 2/SO/sub 4/-Li/sub 2/SO/sub 4/-Y/sub 2/(SO/sub 4/)/sub 3/-SiO/sub 2/ solid electrolyte by a solid reference electrode method

    SciTech Connect (OSTI)

    Imanaka, N.; Yamaguchi, Y.; Adachi, G.; Shiokawa, J.

    1987-03-01

    The electromotive force (EMF) measurement for a Na/sub 2/SO/sub 4/Li/sub 2/SO/sub 4/-Y/sub 2/(SO/sub 4/)/sub 3/-SiO/sub 2/ solid electrolyte was performed both with NiSO/sub 4/-NiO and CoSO/sub 4/-Co/sub 3/O/sub 4/ solid reference SO/sub 2/ electrodes. The measured EMF coincided well with the calculated EMF for a sulfur dioxide gas concentration from 30 ppm to 1% at 973 K. Good agreement between the measured and calculated EMF was also obtained for the SO/sub 2/ gas content from 100 ppm to 1%, at 923 K with the NiSO/sub 4/-NiO electrode.

  9. [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]: A new polymorph of barium vanadium (III) pyrophosphate characterized by intersecting tunnels

    SciTech Connect (OSTI)

    Hwu, Shiou-Jyh; Carroll, R.I.; Serra, D.L. )

    1994-06-01

    Investigation into the synthesis of reduced vanadium phosphate has led to the formation of a new form of the barium vanadium (III) pyrophosphate compound [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]. It is a polymorph of the previously known BaV[sub 2](P[sub 2]O[sub 7])[sub 2], which is now labeled as the [alpha]-phase. The title compound crystallizes in the P-1 (No. 2) space group with a = 6.269 (1) [angstrom], b = 7.864 (3) [angstrom], c = 6.1592 (9) [angstrom], [alpha] = 101.34 (2)[degree], [beta] = 105.84 (1)[degree], and [gamma] = 96.51 (2)[degree]. The structure consists of corner-shared VO[sub 6] octahedra and PO[sub 4] tetrahedra that are connected in V-O-P-O-V and V-O-P-O-P-O-V bonding arrangements. This interesting three-dimensional framework is characterized by seven types of intersecting tunnels, three of which are occupied by the barium cation, while the others are empty. It is important to know that one of the empty tunnels has a relatively large window with a minimum diagonal distance of 4.4 [angstrom], which facilitates a possible framework for a lithium ion insertion reaction. The barium atom has a 10-coordination sphere, BaO[sub 10], in which the oxygen atoms can be viewed as forming two intersecting pseudohexagonal planes. [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2] appears to form at a relatively higher temperature than its polymorph, [alpha]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]. A detailed structural analysis and structural comparison with the [alpha]-phase, as well as a brief comparison with SrV[sub 2](P[sub 2]O[sub 7])[sub 2], are presented.

  10. A cluster with a mixed M{sub 6}X{sub 12}/M{sub 6}X{sub 8} environment: The La{sub 6}Cl{sub 11}Co structure

    SciTech Connect (OSTI)

    Zheng Chong; Mattausch, Hansjuergen; Hoch, Constantin; Simon, Arndt

    2009-08-15

    The title compound was synthesized from La, LaCl{sub 3} and Co under Ar atmosphere at 800 deg. C. It crystallizes in space group P4{sub 2}/n (no. 86) with lattice constants a=11.308(2) A and c=14.441(3) A. The structure features an isolated Co-centered La{sub 6} octahedron with all corners and edges, and 2 of its 8 triangular faces coordinated by Cl atoms. The La{sub 6}Co octahedron is significantly distorted, and the La coordination by Cl atoms deviates from the common close-packing arrangements found in other reduced rare earth metal halides. Structure, bonding and physical properties of the compound have been investigated. - Graphical abstract: La{sub 6}Cl{sub 11}Co octahedron exhibiting a mixed M{sub 6}X{sub 12}/M{sub 6}X{sub 12} coordination environment.

  11. Environmental chamber studies of atmospheric reactivities of volatile organic compounds: Effects of varying chamber and light source

    SciTech Connect (OSTI)

    Carter, W.; Luo, D.; Malkina, I.; Pierce, J.

    1995-05-01

    Photochemical oxidant models are essential tools for assessing effects of emissions changes on ground-level ozone formation. Such models are needed for predicting the ozone impacts of increased alternative fuel use. The gas-phase photochemical mechanism is an important component of these models because ozone is not emitted directly, but is formed from the gas-phase photochemical reactions of the emitted volatile organic compounds (VOCs) and oxides of nitrogen (NO{sub x}) in air. The chemistry of ground level ozone formation is complex; hundreds of types of VOCs being emitted into the atmosphere, and most of their atmospheric reactions are not completely understood. Because of this, no chemical model can be relied upon to give even approximately accurate predictions unless it has been evaluated by comparing its predictions with experimental data. Therefore an experimental and modeling study was conducted to assess how chemical mechanism evaluations using environmental chamber data are affected by the light source and other chamber characteristics. Xenon arc lights appear to give the best artificial representation of sunlight currently available, and experiments were conducted in a new Teflon chamber constructed using such a light source. Experiments were also conducted in an outdoor Teflon Chamber using new procedures to improve the light characterization, and in Teflon chambers using blacklights. These results, and results of previous runs other chambers, were compared with model predictions using an updated detailed chemical mechanism. The magnitude of the chamber radical source assumed when modeling the previous runs were found to be too high; this has implications in previous mechanism evaluations. Temperature dependencies of chamber effects can explain temperature dependencies in chamber experiments when Ta-300{degree}K, but not at temperatures below that.

  12. Thermal expansion of Cr{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12}, Al{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12} and Al{sub 2x}Cr{sub 2-2x}Mo{sub 3}O{sub 12} solid solutions

    SciTech Connect (OSTI)

    Ari, M.; Jardim, P.M.; Marinkovic, B.A. Rizzo, F.; Ferreira, F.F.

    2008-06-15

    The transition temperature from monoclinic to orthorhombic and the thermal expansion of the orthorhombic phase were investigated for three systems of the family A{sub 2}M{sub 3}O{sub 12}: Cr{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12}, Al{sub 2x}Fe{sub 2-2x}Mo{sub 3}O{sub 12} and Al{sub 2x}Cr{sub 2-2x}Mo{sub 3}O{sub 12}. It was possible to obtain a single-phase solid solution in all studied samples (x=0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1). A linear relationship between the transition temperature and the fraction of A{sup 3+} cations (x) was observed for each system. In all orthorhombic solid solutions studied here the observed thermal expansion was anisotropic. These anisotropic thermal expansion properties of crystallographic axes a, b and c result in a low positive or near-zero overall linear coefficient of thermal expansion ({alpha}{sub l}={alpha}{sub V}/3). The relationship between the size of A{sup 3+} cations in A{sub 2}M{sub 3}O{sub 12} and the coefficient of thermal expansion is discussed. Near-zero thermal expansion of Cr{sub 2}Mo{sub 3}O{sub 12} is explained by the behavior of Cr-O and Mo-O bond distances, Cr-Mo non-bond distances and Cr-O-Mo bond angles with increasing temperature, estimated by Rietveld analysis of synchrotron X-ray powder diffraction data. - Graphical abstract: In this figure, all published overall linear coefficients of thermal expansion for orthorhombic A{sub 2}M{sub 3}O{sub 12} family obtained through diffraction methods as a function of A{sup 3+} cation radii size, together with dilatometric results, are plotted. Our results indicate that Cr{sub 2}Mo{sub 3}O{sub 12} does not exactly follow the established relationship.

  13. Structural and thermal studies of H{sub 2}La{sub 2/3}Ta{sub 2}O{sub 7}, a protonated layered perovskite

    SciTech Connect (OSTI)

    Le Berre, F.; Crosnier-Lopez, M.P.; Fourquet, J.L.

    2006-04-13

    We have synthesised the new protonated layered perovskite H{sub 2}La{sub 2/3}Ta{sub 2}O{sub 7} which is related to the Ruddlesden-Popper family. This compound is obtained by ionic exchange starting from Li{sub 2}La{sub 2/3}Ta{sub 2}O{sub 7} maintained in dilute HNO{sub 3} at 60 deg. C. Thermal X-ray diffraction and DTA/TGA revealed interesting dehydration properties with formation of a layered anhydrous phase leading at higher temperature (1550 deg. C) to La{sub 1/3}TaO{sub 3}. This latter compound exhibits the original lanthanum ordering expected similarly to that of the Li form, while at 900 deg. C a metastable form, presenting a disordered La distribution, is observed.

  14. Kinetic study of hydrogen evolution reaction on Ni{sub 30} Mo{sub 70}, Co{sub 30}Mo{sub 70}, Co{sub 30}Ni{sub 70} and Co{sub 10}Ni{sub 20}Mo{sub 70} alloy electrodes

    SciTech Connect (OSTI)

    Dominguez-Crespo, M.A.; Plata-Torres, M.; Torres-Huerta, A.M.; Arce-Estrada, E.M. . E-mail: earce@ipn.mx; Hallen-Lopez, J.M.

    2005-07-15

    The hydrogen evolution reaction on nanocrystalline Ni{sub 30}Mo{sub 70}, Co{sub 30}Mo{sub 70}, Co{sub 30}Ni{sub 70}, and Co{sub 10}Ni{sub 20}Mo{sub 70}, metallic powders prepared by mechanical alloying was investigated with linear polarization and ac impedance methods, in 30 wt.% KOH aqueous solution at room temperature. The formation process and structural properties of these nanocrystalline materials were characterized by X-ray diffraction and transmission electron microscopy. Alloyed powders showed the presence of two phases: an fcc solid solution and intermetallic compounds of Ni, Co and Mo. Based on polarization and ac impedance measurements, an improved electrocatalytic activity for hydrogen evolution reaction was observed in mechanically alloyed Co{sub 30}Ni{sub 70} powders, which is slightly higher than milled metallic Ni powders.

  15. CuYb{sub 2}Ge{sub 4}O{sub 12}, a new bidimensionally tunneled structure

    SciTech Connect (OSTI)

    Campa, J.A.; Cascales, C.; Gueierrez-Puebla, E.; Monge, M.A.; Rasines, I.; Ruiz Valero, C.

    1996-06-01

    Employing CuO as self flux crystals of CuYb{sub 2}Ge{sub 4}O{sub 12} have been grown for the first time. The crystal structure of CuYb{sub 2}Ge{sub 4}O{sub 12} has been determined by single-crystal X-ray diffraction in the triclinic P1 (No. 2) space group to an R value of 6.1%, with (a) = 7.156(2) {Angstrom}, (b) = 7.937(3) {Angstrom}, (c) = 4.905(3) {Angstrom}, {alpha} = 86.63(3){degrees}, {Beta} = 102.41(4){degrees}, {gamma}=1114.12(3){degrees}, V = 248.2(2) {Angstrom}{sup 3}, Z = 1, and D{sub c} = 5.97 gcm{sup {minus}3}. The novel tridimensional CuYb{sub 2}Ge{sub 4}O{sub 12} structure type can be conceived as formed by layers of (GeO{sub 4}){sub 4} units of vertex-sharing GeO{sub 4} squares connecting (GeO{sub 4}){sub 4} units, with channels or tunnels of size up to 4.08 {Angstrom} in the a and c directions. A comparison is made between the structure types of the title germanate and recently reported CuNd{sub 2}Ge{sub 2}O{sub 8}. The temperature dependence from 350 to 1.8 K of the reciprocal dc magnetic susceptibility for CuYb{sub 2}Ge{sub 4}O{sub 12} is shown and presents a deviation from linearity over the whole temperature range. The infrared spectrum between 1000 and 100 cm{sup {minus}1} is given and related with those of comparable species.

  16. Alternative current conduction mechanisms of organic-inorganic compound [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4}

    SciTech Connect (OSTI)

    Ben Bechir, M. Karoui, K.; Guidara, K.; Ben Rhaiem, A.; Tabellout, M.

    2014-04-21

    [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4} has been studied by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and impedance spectroscopy. The [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4} hybrid compound is crystallized at room temperature (T ? 300?K) in the orthorhombic system with Pnma space group. Five phase transitions (T{sub 1}?=?255?K, T{sub 2}?=?282?K, T{sub 3}?=?302?K, T{sub 4}?=?320?K, and T{sub 5}?=?346?K) have been proved by DSC measurements. The electrical technique was measured in the 10{sup ?1}-10{sup 7}?Hz frequency range and 233363?K temperature interval. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law. The AC electrical conduction in [N(CH{sub 3}){sub 3}H]{sub 2}ZnCl{sub 4} is analyzed by different processes, which can be attributed to several models: the correlated barrier hopping model in phase I, the overlapping large polaron tunneling model in phase II, the quantum mechanical tunneling model in phase IV, and the non-overlapping small polaron tunneling model in phases III, V, and VI. The conduction mechanism is studied with the help of Elliot's theory, and the Elliot's parameters are determined.

  17. Alternative current conduction mechanisms of organic-inorganic compound [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4}

    SciTech Connect (OSTI)

    Ben Bechir, M. Karoui, K.; Guidara, K.; Ben Rhaiem, A.; Tabellout, M.

    2014-05-28

    The [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4} single crystal has been analyzed by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and electrical impedance spectroscopy. [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4} crystallizes at room temperature in the monoclinic system with P2{sub 1}/{sub C} space group. Three phase transitions at T{sub 1}?=?226?K, T{sub 2}?=?264?K, and T{sub 3}?=?297?K have been evidenced by DSC measurements. The electrical technique was measured in the 10{sup ?1}10{sup 7}?Hz frequency range and 203313?K temperature intervals. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law (developed). The AC electrical conduction in [N(CH{sub 3}){sub 3}H]{sub 2}CuCl{sub 4} compound is studied by two processes which can be attributed to a hopping transport mechanism: the correlated barrier hopping model in phases I, II, and III, the non-overlapping small polaron tunneling model in phase IV. The conduction mechanism is interpreted with the help of Elliot's theory, and the Elliot's parameters are found.

  18. Crystal-chemistry of mullite-type aluminoborates Al{sub 18}B{sub 4}O{sub 33} and Al{sub 5}BO{sub 9}: A stoichiometry puzzle

    SciTech Connect (OSTI)

    Fisch, Martin; Armbruster, Thomas; Rentsch, Daniel; Libowitzky, Eugen; Pettke, Thomas

    2011-01-15

    Orthorhombic Al{sub 2}O{sub 3}-rich aluminoborate is an important ceramic material for which two slightly different compositions have been assumed: Al{sub 5}BO{sub 9} (5Al{sub 2}O{sub 3}:B{sub 2}O{sub 3}) and Al{sub 18}B{sub 4}O{sub 33} (9Al{sub 2}O{sub 3}:2B{sub 2}O{sub 3}). The formula Al{sub 18}B{sub 4}O{sub 33} (=Al{sub 4.91}B{sub 1.09}O{sub 9}) was derived from results of chemical analyses when crystal structure data were not yet available. Subsequent structural investigations indicated Al{sub 5}BO{sub 9} composition. Nevertheless, Al{sub 18}B{sub 4}O{sub 33} was still accepted as the correct stoichiometry assuming that additional B replaces 9% Al. Powder samples of both compositions and ones with excess boron were prepared by solid state reactions between {alpha}-Al{sub 2}O{sub 3} and B{sub 2}O{sub 3}/H{sub 3}BO{sub 3} at temperatures above 1100 {sup o}C and single-crystals were grown from flux at 1100 and 1550 {sup o}C. Products were investigated by single-crystal and powder XRD, {sup 11}B and {sup 27}Al solid-state MAS-NMR, Raman and FTIR spectroscopy as well as Laser-ablation ICP-MS. No indication of the predicted 9% B{yields}Al substitution was found. LA ICP-MS indicated 12.36(27) wt% B{sub 2}O{sub 3} corresponding to Al{sub 4.97}B{sub 1.03}O{sub 9}. Hence, the suggested Al{sub 18}B{sub 4}O{sub 33} stoichiometry can be excluded for all synthesized samples. A very low amount of Al vacancies at a five-fold coordinated site are likely, charge balanced by an additional nearby three-fold coordinated B site. All evidences indicate that the title compound should be reported as Al{sub 5-x}B{sub 1+x}O{sub 9} with x<0.038(6), which is close to Al{sub 5}BO{sub 9}. -- Graphical abstract: A chemical composition of Al{sub 18}B{sub 4}O{sub 33}=Al{sub 4.91}B{sub 1.09}O{sub 9}=9Al{sub 2}O{sub 3}:2B{sub 2}O{sub 3} has been assumed for mullite-type aluminoborate with Al{sub 5}BO{sub 9} structure. However, samples prepared by different routes showed compositions close to 5Al{sub 2}O{sub 3}:B{sub 2}O{sub 3}. Display Omitted

  19. Volatility characterization of nanoparticles from single and dual-fuel low temperature combustion in compression ignition engines

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lucachick, Glenn; Curran, Scott; Storey, John Morse; Prikhodko, Vitaly Y.; Northrop, William F.

    2016-03-10

    Our work explores the volatility of particles produced from two diesel low temperature combustion (LTC) modes proposed for high-efficiency compression ignition engines. It also explores mechanisms of particulate formation and growth upon dilution in the near-tailpipe environment. Moreover, the number distribution of exhaust particles from low- and mid-load dual-fuel reactivity controlled compression ignition (RCCI) and single-fuel premixed charge compression ignition (PPCI) modes were experimentally studied over a gradient of dilution temperature. Particle volatility of select particle diameters was investigated using volatility tandem differential mobility analysis (V-TDMA). Evaporation rates for exhaust particles were compared with V-TDMA results for candidate pure n-alkanesmore » to identify species with similar volatility characteristics. The results show that LTC particles are mostly comprised of material with volatility similar to engine oil alkanes. V-TDMA results were used as inputs to an aerosol condensation and evaporation model to support the finding that smaller particles in the distribution are comprised of lower volatility material than large particles under primary dilution conditions. Although the results show that saturation levels are high enough to drive condensation of alkanes onto existing particles under the dilution conditions investigated, they are not high We conclude that observed particles from LTC operation must grow from low concentrations of highly non-volatile compounds present in the exhaust.« less

  20. Crystal structures and compressibility of novel iron borides Fe{sub 2}B{sub

    Office of Scientific and Technical Information (OSTI)

    7} and Fe{sub x}B{sub 50} synthesized at high pressure and high temperature (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Crystal structures and compressibility of novel iron borides Fe{sub 2}B{sub 7} and Fe{sub x}B{sub 50} synthesized at high pressure and high temperature Citation Details In-Document Search Title: Crystal structures and compressibility of novel iron borides Fe{sub 2}B{sub 7} and Fe{sub x}B{sub 50} synthesized at high pressure and high

  1. Structure and magnetic interactions in the solid solution Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8}

    SciTech Connect (OSTI)

    Grundmann, Henrik; Schilling, Andreas; Marjerrison, Casey A.; Dabkowska, Hanna A.; Gaulin, Bruce D.

    2013-09-01

    Highlights: We describe for the first time the preparation of single- and polycrystalline members of the solid solution Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8}. We report on the structural changes in the solid solution at room temperature depending on the stoichiometry. We describe the peculiar change of the magnetic behavior in the solid solution with the stoichiometry. - Abstract: Solid solutions of the magnetic insulators Ba{sub 3}Cr{sub 2}O{sub 8} and Sr{sub 3}Cr{sub 2}O{sub 8} (Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8}) have been prepared in polycrystalline form for the first time. Single crystalline material was obtained using a mirror image floating zone technique. X-ray diffraction data taken at room temperature indicate that the space group of Ba{sub 3?x}Sr{sub x}Cr{sub 2}O{sub 8} remains unchanged for all values of x, while the cell parameters depend on the chemical composition, as expected. Magnetization data, measured from 300 K down to 2 K, suggest that the interaction constant J{sub d} within the Cr{sup 5+} dimers varies in a peculiar way as a function of x, starting at J{sub d} = 25 K for x = 0, then first slightly dropping to J{sub d} = 18 K for x ? 0.75, before reaching J{sub d} = 62 K for x = 3.

  2. Synthesis, crystal structure, spectroscopic and thermal properties of [Et{sub 4}N][Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]Br{sub 4}.4H{sub 2}O (Et=ethyl)-A new compound with the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} cluster core

    SciTech Connect (OSTI)

    Peric, Berislav; Jozic, Drazan; Planinic, Pavica; Brnicevic, Nevenka; Giester, Gerald

    2009-09-15

    A new hexanuclear cluster compound, [Et{sub 4}N][Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]Br{sub 4}.4H{sub 2}O (Et=ethyl) (1), with the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} cluster entity, was synthesized and characterized by elemental and TG/DTA analyses, IR and UV/Vis spectroscopy and by a single-crystal X-ray diffraction study. The presence of the paramagnetic [Ta{sub 6}Br{sub 12}]{sup 3+} unit was confirmed also by the room-temperature magnetic and EPR measurements. The compound crystallizes in the tetragonal I4{sub 1}/a space group, with a=14.299(5), c=21.241(5) A, Z=4, R{sub 1}(F)/wR{sub 2}(F{sup 2})=0.0296/0.0811. The structure contains discrete [Ta{sub 6}Br{sub 12}(H{sub 2}O){sub 6}]{sup 3+} cations with an octahedron of metal atoms edge-bridged by bromine atoms and with water molecules occupying all six terminal positions. The cluster units are positioned in the vertices of the three-dimensional (pseudo)diamond lattice. The structure shows similarities with literature reported structures of cluster compounds crystallizing in the diamond (Fd3-barm) space group. - Graphical abstract: Two interpenetrating (pseudo)diamond nets formed by packing of the paramagnetic [Ta{sub 6}Br{sub 12}(H{sub 2}O)]{sup 3+} (octahedral) and diamagnetic [Et{sub 4}N]{sup +} (spheres) cations.

  3. CO<sub>2sub> Storage by Sorption on Organic Matter and Clay in Gas Shale

    SciTech Connect (OSTI)

    Bacon, Diana H.; Yonkofski, Catherine MR; Schaef, Herbert T.; White, Mark D.; McGrail, B. Peter

    2015-10-10

    Simulations of methane production and supercritical carbon dioxide injection were developed that consider competitive adsorption of CH<sub>4sub> and CO<sub>2sub> on both organic matter and montmorillonite. The results were used to assess the potential for storage of CO<sub>2sub> in a hydraulically fractured shale gas reservoir and for enhanced recovery of CH<sub>4sub>. Assuming equal volume fractions of organic matter and montmorillonite, amounts of CO<sub>2sub> adsorbed on both materials were comparable, while methane desorption was from clays was two times greater than desorption from organic material. The most successful strategy considered CO<sub>2sub> injection from a separate well and enhanced methane recovery by 73%, while storing 240 kmt of CO<sub>2sub>.

  4. HIGHLY DEPLETED ETHANE AND MILDLY DEPLETED METHANOL IN COMET 21P/GIACOBINI-ZINNER: APPLICATION OF A NEW EMPIRICAL {nu}{sub 2}-BAND MODEL FOR CH{sub 3}OH NEAR 50 K

    SciTech Connect (OSTI)

    DiSanti, M. A.; Bonev, B. P.; Villanueva, G. L.; Mumma, M. J.

    2013-01-20

    We obtained infrared spectra of Comet 21P/Giacobini-Zinner (hereafter 21P/GZ) using NIRSPEC at Keck II on UT 2005 June 3, approximately one month before perihelion, that simultaneously sampled H{sub 2}O, C{sub 2}H{sub 6}, and CH{sub 3}OH. Our production rate for H{sub 2}O (3.885 {+-} 0.074 Multiplication-Sign 10{sup 28} molecules s{sup -1}) was consistent with that measured during other apparitions of 21P/GZ as retrieved from optical, infrared, and radio observations. Our analysis also provided values for rotational temperature (T {sub rot} = 51 {+-} 3 K) and the abundance ratio of ortho and para spin populations for water (OPR = 2.99 {+-} 0.23, implying a spin temperature exceeding 50 K). Six Q-branches in the {nu}{sub 7} band of C{sub 2}H{sub 6} provided a production rate (5.27 {+-} 0.90 Multiplication-Sign 10{sup 25} s{sup -1}) that corresponded to an abundance ratio of 0.136 {+-} 0.023 Multiplication-Sign 10{sup -2} relative to H{sub 2}O, confirming the previously reported strong depletion of C{sub 2}H{sub 6} from IR observations during the 1998 apparition, and in qualitative agreement with the depletion of C{sub 2} known from optical studies of 21P/GZ. For CH{sub 3}OH, we applied our recently published quantum model for the {nu}{sub 3} band to obtain a rotational temperature (48{sup +10}/{sub -7} K) consistent with that obtained for H{sub 2}O. In addition, we developed a new empirical model for the CH{sub 3}OH {nu}{sub 2} band, based on observations of Comet 8P/Tuttle with NIRSPEC. The application of our {nu}{sub 2} model to 21P/GZ yielded a production rate in agreement with that obtained from the {nu}{sub 3} band. Combining results from both {nu}{sub 2} and {nu}{sub 3} bands provided a production rate (47.5 {+-} 4.4 Multiplication-Sign 10{sup 25} s{sup -1}) that corresponded to an abundance ratio of 1.22 {+-} 0.11 Multiplication-Sign 10{sup -2} relative to H{sub 2}O in 21P/GZ, indicating mild depletion of CH{sub 3}OH. Together with observations of 21P/GZ in 1998, our study provides a measure of primary volatile production rates for this Jupiter family comet over multiple apparitions using high-resolution IR spectroscopy.

  5. K{sub 2}NaOsO{sub 5.5} and K{sub 3}NaOs{sub 2}O{sub 9}: The first osmium perovskites containing alkali cations at the 'A' site

    SciTech Connect (OSTI)

    Mogare, Kailash M.; Klein, Wilhelm; Jansen, Martin

    2012-07-15

    K{sub 2}NaOsO{sub 5.5} and K{sub 3}NaOs{sub 2}O{sub 9} were obtained from solid-state reactions of potassium superoxide, sodium peroxide and osmium metal at elevated oxygen pressures. K{sub 2}NaOsO{sub 5.5} crystallizes as an oxygen-deficient cubic double perovskite in space group Fm3{sup Macron }m with a=8.4184(5) A and contains isolated OsO{sub 6} octahedra. K{sub 3}NaOs{sub 2}O{sub 9} crystallizes hexagonally in P6{sub 3}/mmc with a=5.9998(4) A and c=14.3053(14) A. K{sub 3}NaOs{sub 2}O{sub 9} consists of face sharing Os{sub 2}O{sub 9} pairs of octahedra. According to magnetic measurements K{sub 2}NaOsO{sub 5.5} is diamagnetic, whereas K{sub 3}NaOs{sub 2}O{sub 9} displays strong antiferromagnetic coupling (T{sub N}=140 K), indicating enhanced magnetic interactions within the octahedral pair. - Graphical abstract: High oxidation states of Os, obtained by high oxygen pressure synthesis, are accommodated in double and triple perovskite matrices. K{sub 3}NaOs{sub 2}O{sub 9} displays enhanced magnetic interactions. Highlights: Black-Right-Pointing-Pointer New osmates containing highly oxidized Os were obtained by high O{sub 2} pressure synthesis. Black-Right-Pointing-Pointer High oxidation states of Os are accommodated in double and triple perovskite matrices. Black-Right-Pointing-Pointer Both compounds represent the first Os perovskites with an alkali metal at the A site. Black-Right-Pointing-Pointer K{sub 3}NaOs{sub 2}O{sub 9} displays enhanced magnetic interactions within the octahedral pair.

  6. Silicon etch using SF{sub 6}/C{sub 4}F{sub 8}/Ar gas mixtures

    SciTech Connect (OSTI)

    Bates, Robert L.; Stephan Thamban, P. L.; Goeckner, Matthew J.; Overzet, Lawrence J.

    2014-07-01

    While plasmas using mixtures of SF{sub 6}, C{sub 4}F{sub 8}, and Ar are widely used in deep silicon etching, very few studies have linked the discharge parameters to etching results. The authors form such linkages in this report. The authors measured the optical emission intensities of lines from Ar, F, S, SF{sub x}, CF{sub 2}, C{sub 2}, C{sub 3}, and CS as a function of the percentage C{sub 4}F{sub 8} in the gas flow, the total gas flow rate, and the bias power. In addition, the ion current density and electron temperature were measured using a floating Langmuir probe. For comparison, trenches were etched of various widths and the trench profiles (etch depth, undercut) were measured. The addition of C{sub 4}F{sub 8} to an SF{sub 6}/Ar plasma acts to reduce the availability of F as well as increase the deposition of passivation film. Sulfur combines with carbon in the plasma efficiently to create a large optical emission of CS and suppress optical emissions from C{sub 2} and C{sub 3}. At low fractional flows of C{sub 4}F{sub 8}, the etch process appears to be controlled by the ion flux more so than by the F density. At large C{sub 4}F{sub 8} fractional flows, the etch process appears to be controlled more by the F density than by the ion flux or deposition rate of passivation film. CF{sub 2} and C{sub 2} do not appear to cause deposition from the plasma, but CS and other carbon containing molecules as well as ions do.

  7. A novel technique for measurement of thermal rate constants and temperature dependences of dissociative recombination: CO{sub 2}{sup +}, CF{sub 3}{sup +}, N{sub 2}O{sup +}, C{sub 7}H{sub 8}{sup +}, C{sub 7}H{sub 7}{sup +}, C{sub 6}H{sub 6}{sup +}, C{sub 6}H{sub 5}{sup +}, C{sub 5}H{sub 6}{sup +}, C{sub 4}H{sub 4}{sup +}, and C{sub 3}H{sub 3}{sup +}

    SciTech Connect (OSTI)

    Fournier, Joseph A.; Shuman, Nicholas S.; Melko, Joshua J.; Ard, Shaun G.; Viggiano, Albert A.

    2013-04-21

    A novel technique using a flowing afterglow-Langmuir probe apparatus for measurement of temperature dependences of rate constants for dissociative recombination (DR) is presented. Low ({approx}10{sup 11} cm{sup -3}) concentrations of a neutral precursor are added to a noble gas/electron afterglow plasma thermalized at 300-500 K. Charge exchange yields one or many cation species, each of which may undergo DR. Relative ion concentrations are monitored at a fixed reaction time while the initial plasma density is varied between 10{sup 9} and 10{sup 10} cm{sup -3}. Modeling of the decrease in concentration of each cation relative to the non-recombining noble gas cation yields the rate constant for DR. The technique is applied to several species (O{sub 2}{sup +}, CO{sub 2}{sup +}, CF{sub 3}{sup +}, N{sub 2}O{sup +}) with previously determined 300 K values, showing excellent agreement. The measurements of those species are extended to 500 K, with good agreement to literature values where they exist. Measurements are also made for a range of C{sub n}H{sub m}{sup +} (C{sub 7}H{sub 7}{sup +}, C{sub 7}H{sub 8}{sup +}, C{sub 5}H{sub 6}{sup +}, C{sub 4}H{sub 4}{sup +}, C{sub 6}H{sub 5}{sup +}, C{sub 3}H{sub 3}{sup +}, and C{sub 6}H{sub 6}{sup +}) derived from benzene and toluene neutral precursors. C{sub n}H{sub m}{sup +} DR rate constants vary from 8-12 Multiplication-Sign 10{sup -7} cm{sup 3} s{sup -1} at 300 K with temperature dependences of approximately T{sup -0.7}. Where prior measurements exist these results are in agreement, with the exception of C{sub 3}H{sub 3}{sup +} where the present results disagree with a previously reported flat temperature dependence.

  8. Nuclear and magnetic supercells in the multiferroic candidate: Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14}

    SciTech Connect (OSTI)

    Silverstein, Harlyn J.; Huq, Ashfia; Lee, Minseong; Choi, Eun Sang; Zhou, Haidong; Wiebe, Christopher R.

    2015-01-15

    The dugganites, Te{sup 6+}-containing members of the langasite series, have attracted recent interest due to their complex low-temperature magnetic unit cells, magnetodielectric, and potentially multiferroic properties. For Pb{sup 2+}-containing dugganites, a large monoclinic supercell was reported and was found to have a profound effect on the low temperature magnetism and spin excitation spectra. Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14} is another dugganite previously shown to distort away from the canonical P321 langasite unit cell, although this supercell was never fully solved. Here we report the full crystal and magnetic structure solution of Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14} using synchrotron x-ray and neutron diffraction data: a large trigonal supercell is observed in this material, which is believed to be the first supercell of its kind in the langasite family. Here, the magnetic structure, high-magnetic field behavior, and dielectric properties of Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14} are presented. In addition to showing weak magnetoelectric behavior similar to other langasites, it was found that a phase transition occurs at 3 T near the antiferromagnetic transition temperature. - Graphical abstract: The nuclear supercell of Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14}, found through joint refinements using high resolution synchrotron X-ray and neutron powder diffraction, retains the trigonal symmetry of the subcell. - Highlights: • Large P3 supercell found in Pb{sub 3}TeMn{sub 3}P{sub 2}O{sub 14}. • Complex helical spin structures below T{sub N}=6.6 K. • Phase transition at 3 T found using through dielectric and DC susceptibility measurements. • Moment saturation near 25 T at 1.4 K.

  9. Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs<sub>2sub>CuBr>4sub>

    SciTech Connect (OSTI)

    Zvyagin, S. A.; Ozerov, M.; Kamenskyi, D.; Wosnitza, J.; Krzystek, J.; Yoshizawa, D.; Hagiwara, M.; Hu, Rongwei; Ryu, Hyejin; Petrovic, C.; Zhitomirsky, M. E.

    2015-11-27

    We present on high- field electron spin resonance (ESR) studies of magnetic excitations in the spin- 1/2 triangular-lattice antiferromagnet Cs<sub>2sub>CuBr>4sub>. Frequency- field diagrams of ESR excitations are measured for different orientations of magnetic fields up to 25 T. We show that the substantial zero- field energy gap, Δ ≈ 9.5 K, observed in the low-temperature excitation spectrum of Cs<sub>2sub>CuBr>4sub> [Zvyagin et al:, Phys. Rev. Lett. 112, 077206 (2014)], is present well above T<sub>N>. Noticeably, the transition into the long-range magnetically ordered phase does not significantly affect the size of the gap, suggesting that even below T<sub>N> the high-energy spin dynamics in Cs<sub>2sub>CuBr>4sub> is determined by short-range-order spin correlations. The experimental data are compared with results of model spin-wave-theory calculations for spin-1/2 triangle-lattice antiferromagnet.

  10. Electronic structure and optical properties of ?-(Fe{sub 1-x}V{sub x}){sub 2}O{sub 3} solid-solution thin films

    SciTech Connect (OSTI)

    Chamberlin, S. E.; Nayyar, I. H.; Kaspar, T. C.; Sushko, P. V.; Chambers, S. A.

    2015-01-26

    We have examined the effect of V doping on the electronic and optical properties of epitaxial hematite (?-Fe{sub 2}O{sub 3}) thin films, by employing several characterization techniques and computational modeling. The conductivity of ?-(Fe{sub 1-x}V{sub x}){sub 2}O{sub 3} (0???x????0.5) is enhanced by several orders of magnitude as x is increased, as evidenced by electrical resistivity measurements and x-ray photoelectron spectroscopy core-level and valence-band spectra. Optical absorption shows a reduction in the direct band gap by as much as 0.64?eV for x?=?0.53 (E{sub g}?=?1.46?eV) relative to that of ?-Fe{sub 2}O{sub 3} (E{sub g}?=?2.10?eV). Detailed understanding of the character of the optical transitions in the alloys is achieved using first-principles calculations of the ground and excited states. These calculations reveal that V doping results in occupied V 3d orbitals hybridized with Fe orbitals and located at approximately mid-gap in ?-Fe{sub 2}O{sub 3}. The lowest energy transitions involve charge transfer from occupied V 3d to unoccupied Fe 3d* orbitals. With a low band gap and high conductivity, ?-(Fe{sub 1-x}V{sub x}){sub 2}O{sub 3} is a promising material for photovoltaic and photoelectrochemical applications.

  11. Phase-diagram study for the Al{sub 2}O{sub 3}-CaF{sub 2}-SiO{sub 2} system

    SciTech Connect (OSTI)

    Ueda, Shigeru; Maeda, Masafumi

    1999-10-01

    Phase relations for the Al{sub 2}O{sub 3}-CaF{sub 2}-SiO{sub 2} system were investigated from 1,673 to 1,723 K. The hot-filament technique was applied to observe a two-liquid region and liquidus for the ternary system. The liquidus saturated with SiO{sub 2} was investigated at 1673 K by using the hot-filament technique and the chemical equilibrium technique. In this system, the addition of Al{sub 2}O{sub 3} to the CaF{sub 2}-SiO{sub 2} system reduces the congruent temperature. A small substitution of Al{sub 2}O{sub 3} for CaF{sub 2} increases the solubility of SiO{sub 2}, namely, if the region of liquid phase could be enlarged. These results suggest that Al{sub 2}O{sub 3} would be an effective substitute of CaF{sub 2} in slag for steelmaking.

  12. Development of epitaxial Al<sub>xSc>1-xsub>N for artificially structured metal/semiconductor superlattice metamaterials

    SciTech Connect (OSTI)

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The Al<sub>xSc>1-xsub>N alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x < 0.51. Employing 20 nm TiN as a seed layer on MgO substrates, the homogeneity range for stabilizing the rocksalt phase has been extended to x < 0.82 for a 120 nm film. The rocksalt Al<sub>xSc>1-xsub>N alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 ± 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 ± 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt Al<sub>xSc>1-xsub>N alloys enable high quality epitaxial rocksalt metal/Al<sub>xSc>1-xsub>N superlattices with a wide range of accessible metamaterials properties.

  13. Facile synthesis and characterization of ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres

    SciTech Connect (OSTI)

    Shen, Yu [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China) [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Li, Xinyong, E-mail: xyli@dlut.edu.cn [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China) [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia); Zhao, Qidong; Hou, Yang [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China)] [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Tade, Moses [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)] [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia); Liu, Shaomin, E-mail: Shaomin.Liu@curtin.edu.au [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)] [Department of Chemical Engineering, Curtin University, Perth, WA 6845 (Australia)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres were successfully synthesized via a facile method. Black-Right-Pointing-Pointer Detailed structural, morphology and the phase composition were studied. Black-Right-Pointing-Pointer The incorporation of ZnFe{sub 2}O{sub 4} and {alpha}-Fe{sub 2}O{sub 3} gives an appropriate band gap value to utilize solar energy. -- Abstract: ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres were successfully fabricated via a facile one-pot solvothermal method, utilizing polyethylene glycol as soft template. X-ray diffraction and scanning electron microscopy analysis revealed that the prepared nanospheres with cubic spinel and rhombohedra composite structure had a uniform diameter of about 370 nm, and the hollow structure could be further confirmed by transmission electron microscopy. Energy dispersive X-ray, X-ray photoelectron spectroscopy and Fourier transform infrared techniques were also applied to characterize the elemental composition and chemical bonds in the hollow nanospheres. The ZnFe{sub 2}O{sub 4}/{alpha}-Fe{sub 2}O{sub 3} composite hollow nanospheres show attractive light absorption property for potential applications in electronics, optics, and catalysis.

  14. Redox probing study of the potential dependence of charge transport through Li<sub>2sub>O>2sub>

    SciTech Connect (OSTI)

    Knudsen, Kristian B.; Luntz, Alan C.; Jensen, Søren H.; Vegge, Tejs; Hjelm, Johan

    2015-11-20

    In the field of energy storage devices the pursuit for cheap, high energy density, reliable secondary batteries is at the top of the agenda. The Li–O<sub>2sub> battery is one of the possible technologies that, in theory, should be able to close the gap, which exists between the present state-of-the-art Li-ion technologies and the demand placed on batteries by technologies such as electrical vehicles. Here we present a redox probing study of the charge transfer across the main deposition product lithium peroxide, Li<sub>2sub>O>2sub>, in the Li–O<sub>2sub> battery using outer-sphere redox shuttles. The change in heterogeneous electron transfer exchange rate as a function of the potential and the Li<sub>2sub>O>2sub> layer thickness (~depth-of-discharge) was determined using electrochemical impedance spectroscopy. In addition, the attenuation of the electron transfer exchange rate with film thickness is dependent on the probing potential, providing evidence that hole transport is the dominant process for charge transfer through Li<sub>2sub>O>2sub> and showing that the origin of the sudden death observed upon discharge is due to charge transport limitations.

  15. Thermal conductivity of bulk and nanowire Mg?Si<sub>xSn>1xsub> alloys from first principles

    SciTech Connect (OSTI)

    Li, Wu; Lindsay, L.; Broido, D. A.; Stewart, Derek A.; Mingo, Natalio

    2012-11-29

    The lattice thermal conductivity (?) of the thermoelectric materials, Mg?Si, Mg?Sn, and their alloys, are calculated for bulk and nanowires, without adjustable parameters. We find good agreement with bulk experimental results. For large nanowire diameters, size effects are stronger for the alloy than for the pure compounds. For example, in 200 nm diameter nanowires ? is lower than its bulk value by 30%, 20%, and 20% for Mg?Si?.?Sn?.?, Mg?Si, and Mg?Sn, respectively. For nanowires less than 20 nm thick, the relative decrease surpasses 50%, and it becomes larger in the pure compounds than in the alloy. At room temperature, ? of Mg?Si<sub>xSn>1xsub> is less sensitive to nanostructuring size effects than Si<sub>xGe>1xsub>, but more sensitive than PbTe<sub>xSe>1xsub>. This suggests that further improvement of Mg?Si<sub>xSn>1xsub> as a nontoxic thermoelectric may be possible.

  16. Development of epitaxial Al<sub>xSc>1-xsub>N for artificially structured metal/semiconductor superlattice metamaterials

    SciTech Connect (OSTI)

    Sands, Timothy D.; Stach, Eric A.; Saha, Bivas; Saber, Sammy; Naik, Gururaj V.; Boltasseva, Alexandra; Kvam, Eric P.

    2015-02-01

    Epitaxial nitride rocksalt metal/semiconductor superlattices are emerging as a novel class of artificially structured materials that have generated significant interest in recent years for their potential application in plasmonic and thermoelectric devices. Though most nitride metals are rocksalt, nitride semiconductors in general have hexagonal crystal structure. We report rocksalt aluminum scandium nitride (Al,Sc)N alloys as the semiconducting component in epitaxial rocksalt metal/semiconductor superlattices. The Al<sub>xSc>1-xsub>N alloys when deposited directly on MgO substrates are stabilized in a homogeneous rocksalt (single) phase when x < 0.51. Employing 20 nm TiN as a seed layer on MgO substrates, the homogeneity range for stabilizing the rocksalt phase has been extended to x < 0.82 for a 120 nm film. The rocksalt Al<sub>xSc>1-xsub>N alloys show moderate direct bandgap bowing with a bowing parameter, B = 1.41 0.19 eV. The direct bandgap of metastable rocksalt AlN is extrapolated to be 4.70 0.20 eV. The tunable lattice parameter, bandgap, dielectric permittivity, and electronic properties of rocksalt Al<sub>xSc>1-xsub>N alloys enable high quality epitaxial rocksalt metal/Al<sub>xSc>1-xsub>N superlattices with a wide range of accessible metamaterials properties.

  17. Single-vortex pinning and penetration depth in superconducting NdFeAsO<sub>1-xsub>Fx>

    SciTech Connect (OSTI)

    Zhang, Jessie T.; Kim, Jeehoon; Huefner, Magdalena; Ye, Cun; Kim, Stella; Canfield, Paul C.; Prozorov, Ruslan; Auslaender, Ophir M.; Hoffman, Jennifer E.

    2015-10-12

    We use a magnetic force microscope (MFM) to investigate single vortex pinning and penetration depth in NdFeAsO<sub>1-xsub>Fx>, one of the highest-T<sub>c> iron-based superconductors. In fields up to 20 Gauss, we observe a disordered vortex arrangement, implying that the pinning forces are stronger than the vortex-vortex interactions. We measure the typical force to depin a single vortex, F<sub>depin> ≃ 4.5 pN, corresponding to a critical current up to J<sub>c> ≃ 7×105 A/cm2. As a result, our MFM measurements allow the first local and absolute determination of the superconducting in-plane penetration depth in NdFeAsO<sub>1-xsub>Fx>, λ<sub>ab> = 320 ± 60 nm, which is larger than previous bulk measurements.

  18. Design of Semiconducting Tetrahedral Mn1<sub>-xZnx>O Alloys and Their Application to Solar Water Splitting

    SciTech Connect (OSTI)

    Peng, Haowei; Ndione, Paul F.; Ginley, David S.; Zakutayev, A.; Lany, Stephen

    2015-05-18

    Both structure-property and composition-structure relationships are exploited to design and realize novel wurtzite-structure Mn1<sub>-xZnx>O alloys. A proof of principle is provided that corroborates, in particular, the predicted favorable hole-transport properties of these alloys.

  19. Combined effects of post-growth thermal treatment and chemical substitution on physical properties of CaFe<sub>2sub>As>2sub>

    SciTech Connect (OSTI)

    Ran, Sheng

    2014-12-01

    This thesis summarizes experimental work using process of postgrowth thermal treatment and chemical substitution as tuning parameters in the study of physical properties of CaFe<sub>2sub>As>2sub>. Details of sample preparation and characterization are given as well as various phase diagrams.

  20. Sintered Cr/Pt and Ni/Au ohmic contacts to B<sub>12sub>P>2sub>

    SciTech Connect (OSTI)

    Frye, Clint D.; Kucheyev, Sergei O.; Edgar, James H.; Voss, Lars F.; Conway, Adam M.; Shao, Qinghui; Nikolic, Rebecca J.

    2015-04-09

    With this study, icosahedral boron phosphide (B<sub>12sub>P>2sub>) is a wide-bandgap semiconductor possessing interesting properties such as high hardness, chemical inertness, and the reported ability to self-heal from irradiation by high energy electrons. Here, the authors developed Cr/Pt and Ni/Au ohmic contacts to epitaxially grown B<sub>12sub>P>2sub> for materials characterization and electronic device development. Cr/Pt contacts became ohmic after annealing at 700 °C for 30 s with a specific contact resistance of 2×10–4 Ω cm2, as measured by the linear transfer length method. Ni/Au contacts were ohmic prior to any annealing, and their minimum specific contact resistance was ~l–4 × 10–4 Ω cm2 after annealing over the temperature range of 500–800 °C. Rutherford backscattering spectrometry revealed a strong reaction and intermixing between Cr/Pt and B<sub>12sub>P>2sub> at 700 °C and a reaction layer between Ni and B<sub>12sub>P>2sub> thinner than ~25 nm at 500 °C.

  1. Response of fine particulate matter to emission changes of oxides of nitrogen and anthropogenic volatile organic compounds in the eastern United States

    SciTech Connect (OSTI)

    Alexandra P. Tsimpidi; Vlassis A. Karydis; Spyros N. Pandis

    2008-11-15

    A three-dimensional chemical transport model (Particulate Matter Comprehensive Air Quality Model with Extensions) is used to investigate changes in fine particle (PM2.5) concentrations in response to 50% emissions changes of oxides of nitrogen (NOx) and anthropogenic volatile organic compounds (VOCs) during July 2001 and January 2002 in the eastern United States. The reduction of NOx emissions by 50% during the summer results in lower average oxidant levels and lowers PM2.5 (8% on average), mainly because of reductions of sulfate (9-11%), nitrate (45-58%), and ammonium (7-11%). The organic particulate matter (PM) slightly decreases in rural areas, whereas it increases in cities by a few percent when NOx is reduced. Reduction of NOx during winter causes an increase of the oxidant levels and a rather complicated response of the PM components, leading to small net changes. Sulfate increases (8-17%), nitrate decreases (18-42%), organic PM slightly increases, and ammonium either increases or decreases a little. The reduction of VOC emissions during the summer causes on average a small increase of the oxidant levels and a marginal increase in PM2.5. This small net change is due to increases in the inorganic components and decreases of the organic ones. Reduction of VOC emissions during winter results in a decrease of the oxidant levels and a 5-10% reduction of PM2.5 because of reductions in nitrate (4-19%), ammonium (4-10%), organic PM (12-14%), and small reductions in sulfate. Although sulfur dioxide (SO{sub 2}) reduction is the single most effective approach for sulfate control, the coupled decrease of SO{sub 2} and NOx emissions in both seasons is more effective in reducing total PM2.5 mass than the SO{sub 2} reduction alone. 34 refs., 7 figs., 1 tab.

  2. Surface reactions of ethanol over UO<sub>2sub>(100) thin film

    SciTech Connect (OSTI)

    S. D. Senanayake; Mudiyanselage, K.; Burrell, A. K.; Sadowski, J. T.; Idriss, H.

    2015-10-08

    The study of the reactions of oxygenates on well-defined oxide surfaces is important for the fundamental understanding of heterogeneous chemical pathways that are influenced by atomic geometry, electronic structure, and chemical composition. In this work, an ordered uranium oxide thin film surface terminated in the (100) orientation is prepared on a LaAlO<sub>3sub> substrate and studied for its reactivity with a C-2 oxygenate, ethanol (CH<sub>3sub>CH>2sub>OH). With the use of synchrotron X-ray photoelectron spectroscopy (XPS), we have probed the adsorption and desorption processes observed in the valence band, C 1s, O 1s, and U 4f to investigate the bonding mode, surface composition, electronic structure, and probable chemical changes to the stoichiometric-UO<sub>2sub>(100) [smooth-UO<sub>2sub>(100)] and Ar+-sputtered UO<sub>2sub>(100) [rough-UO<sub>2sub>(100)] surfaces. Unlike UO<sub>2sub>(111) single crystal and UO<sub>2sub> thin film, Ar-ion-sputtering of this UO<sub>2sub>(100) did not result in noticeable reduction of U cations. Upon ethanol adsorption (saturation occurred at 0.5 ML), only the ethoxy (CH<sub>3sub>CH>2sub>O) species is formed on smooth-UO<sub>2sub>(100) whereas initially formed ethoxy species are partially oxidized to surface acetate (CH3COO–) on the Ar+-sputtered UO<sub>2sub>(100) surface. Furthermore, all ethoxy and acetate species are removed from the surface between 600 and 700 K.

  3. New simple A{sub 4} neutrino model for nonzero {theta}{sub 13} and large {delta}{sub CP}

    SciTech Connect (OSTI)

    Ishimori, Hajime

    2013-05-23

    In a new simple application of the non-Abelian discrete symmetry A{sub 4} to charged-lepton and neutrino mass matrices, we show that for the current experimental central value of sin{sup 2} 2{theta}{sub 13} Asymptotically-Equal-To 0.1, leptonic CP violation is necessarily large, i.e. Double-Vertical-Line tan{delta}{sub CP} Double-Vertical-Line > 1.3. We also consider T{sub 7} model with one parameter to be complex, thus allowing for one Dirac CP phase {delta}{sub CP} and two Majorana CP phases {alpha}{sub 1,2}. We find a slight modification to this correlation as a function of {delta}{sub CP}. For a given set of input values of {Delta}m{sup 2}{sub 21}, {Delta}m{sup 2}{sub 32}, {theta}{sub 12}, and {theta}{sub 13}, we obtain sin{sup 2} 2{theta}{sub 23} and m{sub ee} (the effective Majorana neutrino mass in neutrinoless double beta decay) as functions of tan {delta}{sub CP}. We find that the structure of this model always yields small Double-Vertical-Line tan {delta}{sub CP} Double-Vertical-Line .

  4. Microstructures and properties of CH{sub 3}NH{sub 3}PbI{sub 3?x}Cl{sub x} hybrid solar cells

    SciTech Connect (OSTI)

    Suzuki, Kohei E-mail: oku@mat.usp.ac.jp; Suzuki, Atsushi E-mail: oku@mat.usp.ac.jp; Zushi, Masahito E-mail: oku@mat.usp.ac.jp; Oku, Takeo E-mail: oku@mat.usp.ac.jp

    2015-02-27

    Halide-perovskite CH{sub 3}NH{sub 3}PbI{sub 3} was produced on mesoporous TiO{sub 2} layer by spin-coating a precursor solution of PbCl{sub 2} and CH{sub 3}NH{sub 3}I in dimethylformamide. The role of the annealing process and chlorine (Cl) doping for the perovskite-phase formation was investigated. It was found that crystallization of the perovskite materials was stimulated by the annealing process, and that longer annealing time is necessary for the Cl-doped perovskite compared with that of non-doped perovskite phase.

  5. Hysteretic electrical transport in BaTiO{sub 3}/Ba{sub 1?x}Sr{sub x}TiO{sub 3}/Ge heterostructures

    SciTech Connect (OSTI)

    Ngai, J. H.; Kumah, D. P.; Walker, F. J.; Ahn, C. H.

    2014-02-10

    We present electrical transport measurements of heterostructures comprised of BaTiO{sub 3} and Ba{sub 1?x}Sr{sub x}TiO{sub 3} epitaxially grown on Ge. Sr alloying imparts compressive strain to the BaTiO{sub 3}, which enables the thermal expansion mismatch between BaTiO{sub 3} and Ge to be overcome to achieve c-axis oriented growth. The conduction bands of BaTiO{sub 3} and Ba{sub 1?x}Sr{sub x}TiO{sub 3} are nearly aligned with the conduction band of Ge, which facilitates electron transport. Electrical transport measurements through the dielectric stack exhibit rectifying behavior and hysteresis, where the latter is consistent with ferroelectric switching.

  6. Resolution of the discrepancy between the variation of the physical properties of Ce<sub>1-xsub>YbxCoIn>5sub> single crystals and thin films with Yb composition

    SciTech Connect (OSTI)

    Jang, S.; White, B. D.; Lum, I. K.; Kim, H.; Tanatar, M. A.; Straszheim, W. E.; Prozorov, R.; Keiber, T.; Bridges, F.; Shu, L.; Baumbach, R. E.; Janoschek, M.; Maple, M. B.

    2014-11-18

    The extraordinary electronic phenomena including an Yb valence transition, a change in Fermi surface topology, and suppression of the heavy fermion quantum critical field at a nominal concentration x≈0.2 have been found in the Ce<sub>1-xsub>YbxCoIn>5sub> system. These phenomena have no discernable effect on the unconventional superconductivity and normal-state non-Fermi liquid behaviour that occur over a broad range of x up to ~0.8. However, the variation of the coherence temperature T* and the superconducting critical temperature T<sub>c> with nominal Yb concentration x for bulk single crystals is much weaker than that of thin films. To determine whether differences in the actual Yb concentration of bulk single crystals and thin film samples might be responsible for these discrepancies, we employed Vegard’s law and the spectroscopically determined values of the valences of Ce and Yb as a function of x to determine the actual composition x<sub>act> of bulk single crystals. This analysis is supported by energy-dispersive X-ray spectroscopy, wavelength-dispersive X-ray spectroscopy, and transmission X-ray absorption edge spectroscopy measurements. The actual composition x<sub>act> is found to be about one-third of the nominal concentration x up to x~0.5, and resolves the discrepancy between the variation of the physical properties of Ce<sub>1-xsub>YbxCoIn>5sub> single crystals and thin films with Yb concentration.

  7. Yb{sub 5}Ni{sub 4}Sn{sub 10} and Yb{sub 7}Ni{sub 4}Sn{sub 13}: New polar intermetallics with 3D framework structures

    SciTech Connect (OSTI)

    Lei Xiaowu; Sun Zhongming; Li Longhua; Zhong Guohua; Hu Chunli; Mao Jianggao

    2010-04-15

    The title compounds have been obtained by solid state reactions of the corresponding pure elements at high temperature, and structurally characterized by single-crystal X-ray diffraction studies. Yb{sub 5}Ni{sub 4}Sn{sub 10} adopts the Sc{sub 5}Co{sub 4}Si{sub 10} structure type and crystallizes in the tetragonal space group P4/mbm (No. 127) with cell parameters of a=13.785(4) A, c=4.492 (2) A, V=853.7(5) A{sup 3}, and Z=2. Yb{sub 7}Ni{sub 4}Sn{sub 13} is isostructural with Yb{sub 7}Co{sub 4}InGe{sub 12} and crystallizes in the tetragonal space group P4/m (No. 83) with cell parameters of a=11.1429(6) A, c=4.5318(4) A, V=562.69(7) A{sup 3}, and Z=1. Both structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are occupied by the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic. These results are in agreement with those from temperature-dependent resistivity and magnetic susceptibility measurements. - Graphical abstract: Two new ytterbium nickel stannides, namely, Yb{sub 5}Ni{sub 4}Sn{sub 10} and Yb{sub 7}Ni{sub 4}Sn{sub 13}, have been synthesized and structurally characterized by single-crystal X-ray diffraction studies. Both their structures feature three-dimensional (3D) frameworks based on three different types of one-dimensional (1D) channels, which are situated by all the Yb atoms. Electronic structure calculations based on density functional theory (DFT) indicate that both compounds are metallic, which are in accordance with the results from temperature-dependent resistivity and magnetic susceptibility measurements.

  8. Synthesis, structure and chemical bonding of CaFe{sub 2?x}Rh{sub x}Si{sub 2} (x=0, 1.32, and 2) and SrCo{sub 2}Si{sub 2}

    SciTech Connect (OSTI)

    Hlukhyy, Viktor Hoffmann, Andrea V.; Fssler, Thomas F.

    2013-07-15

    The finding of superconductivity in Ba{sub 0.6}K{sub 0.4}Fe{sub 2}As{sub 2} put the attention on the investigation of compounds that crystallize with ThCr{sub 2}Si{sub 2} structure type such as AT{sub 2}X{sub 2} (A=alkali/alkaline earth/rare earth element; T=transition metal and X=element of the 1315th group). In this context the silicides CaFe{sub 2}Si{sub 2}, CaFe{sub 0.68(6)}Rh{sub 1.32(6)}Si{sub 2}, CaRh{sub 2}Si{sub 2} and SrCo{sub 2}Si{sub 2} have been synthesized by reaction of the elements under an argon atmosphere. Single crystals were obtained by special heat treatment in welded niobium/tantalum ampoules. The compounds were investigated by means of powder and single crystal X-ray diffraction. All compounds crystallize in the ThCr{sub 2}Si{sub 2}-type structure with space group I4/mmm (No. 139): a=3.939(1) , c=10.185(1) , R{sub 1}=0.045, 85 F{sup 2} values, 8 variable parameters for CaFe{sub 2}Si{sub 2}; a=4.0590(2) , c=9.9390(8) , R{sub 1}=0.030, 90 F{sup 2} values, 10 variable parameters for CaFe{sub 0.68(6)}Rh{sub 1.32(6)}Si{sub 2}; a=4.0695(1) , c=9.9841(3) , R{sub 1}=0.031, 114 F{sup 2} values, 9 variable parameters for CaRh{sub 2}Si{sub 2}; and a=3.974(1) , c=10.395(1) , R{sub 1}=0.036, 95 F{sup 2} values, 8 variable parameters for SrCo{sub 2}Si{sub 2}. The structure of SrCo{sub 2}Si{sub 2} contains isolated [Co{sub 2}Si{sub 2}]{sup 2?} 2D-layers in the ab-plane whereas in CaFe{sub 2?x}Rh{sub x}Si{sub 2} the [T{sub 2}Si{sub 2}] layers (T=Fe and Rh) are interconnected along the c-axis via Si3Si bonds resulting in a three-dimentional (3D) [T{sub 2}Si{sub 2}]{sup 2?} polyanions and therefore belong to the so-called collapsed form of the ThCr{sub 2}Si{sub 2}-type structure. The SrCo{sub 2}Si{sub 2} and CaRh{sub 2}Si{sub 2} are isoelectronic to the parent 122 ironpnictide superconductors AeFe{sub 2}As{sub 2} (Ae=alkaline earth elements), whereas CaFe{sub 2}Si{sub 2} is a full substituted variant (As/Si) of CaFe{sub 2}As{sub 2}. The crystal chemistry and chemical bonding in the title compounds are discussed in terms of LMTO band structure calculations and a topological analysis using the Electron Localization Function (ELF). - Graphical abstract: The SrCo{sub 2}Si{sub 2} and CaFe{sub 2?x}Rh{sub x}Si{sub 2} (x==0, 1.32, and 2) crystallize in the ThCr{sub 2}Si{sub 2}-type. The structure of SrCo{sub 2}Si{sub 2} contains isolated [Co{sub 2}Si{sub 2}]{sup 2?} layers in the ab-plane, whereas the [T{sub 2}Si{sub 2}] layers in CaFe{sub 2?x}Rh{sub x}Si{sub 2} are interconnected along the c-axis via Si3Si bonds resulting in a [T{sub 2}Si{sub 2}]{sup 2?} network. - Highlights: Synthesis and structure of ternary silicides SrCo{sub 2}Si{sub 2} and CaFe{sub 2?x}Rh{sub x}Si{sub 2} (x=0, 1.32, and 2). The SrCo{sub 2}Si{sub 2} and CaRh{sub 2}Si{sub 2} are isoelectronic to the parent 122 ironpnictide superconductors AeFe{sub 2}As{sub 2}. CaFe{sub 2}Si{sub 2} is a full substituted variant (As/Si) of superconductor CaFe{sub 2}As{sub 2}. The title compounds demonstrate the tunable Si3Si distances.

  9. Heavy fermion Ce{sub 3}Co{sub 4}Sn{sub 13} compound under pressure

    SciTech Connect (OSTI)

    Collave, J. R.; Borges, H. A.; Ramos, S. M.; Hering, E. N.; Mendona-Ferreira, L.; Pagliuso, P. G.

    2015-05-07

    The non-magnetic heavy fermion compound Ce{sub 3}Co{sub 4}Sn{sub 13} was studied under pressure. We report single crystalline measurements of electrical resistivity as a function of temperature ?(T) under pressure. Some characteristic features related to a structural transition (T{sub S}), crystalline field effects (T{sub CEF}), and a low temperature maximum (T{sub max}), possibly connected simultaneously to the onset of Kondo lattice coherence and short range magnetic correlations, were identified in the ?(T) data. A pressure-temperature phase diagram with T{sub S} and T{sub max} was constructed by mapping these features. Like for most Ce-based heavy fermion compounds, T{sub max} moves to higher temperatures with pressure, indicating that it is related to the Kondo energy scale, due to the increase of hybridization induced by pressure. On the other hand, T{sub S}, associated to a superlattice distortion and probably combined with a charge density wave transition, decreases as a function of pressure. However, differently from the Sr{sub 3?x}Ca{sub x}Ir{sub 4}Sn{sub 13} system, where a superlattice quantum phase transition is observed [L. E. Klintberg et al., Phys. Rev. Lett. 109, 237?008 (2012)], in Ce{sub 3}Co{sub 4}Sn{sub 13} T{sub S}???154?K, at ambient pressure (P?=?0), seems to stabilize at around 143?K for P???19 kilobars. We also investigated ?(T) in external magnetic fields, at P?=?0. Negative magnetoresistance and increase of T{sub max} are observed, suggesting suppression of low temperature short range magnetic correlations.

  10. Dynamics of the reaction of C{sub 3}(a{sup 3}Π{sub u}) radicals with C{sub 2}H{sub 2}: A new source for the formation of C{sub 5}H

    SciTech Connect (OSTI)

    Huang, Wen-Jian; Sun, Yi-Lun; Chin, Chih-Hao; Lee, Shih-Huang

    2014-09-28

    The reaction C{sub 3}(a{sup 3}Π{sub u}) + C{sub 2}H{sub 2} → C{sub 5}H + H was investigated at collision energy 10.9 kcal mol{sup −1} that is less than the enthalpy of ground-state reaction C{sub 3}(X{sup 1}Σ{sub g}{sup +}) + C{sub 2}H{sub 2} → C{sub 5}H + H. C{sub 3}(a{sup 3}Π{sub u}) radicals were synthesized from 1% C{sub 4}F{sub 6}/He by pulsed high-voltage discharge. The title reaction was conducted in a crossed molecular-beam apparatus equipped with a quadrupole-mass filter. Product C{sub 5}H was interrogated with time-of-flight spectroscopy and synchrotron vacuum-ultraviolet ionization. Reactant C{sub 3}(a{sup 3}Π{sub u}) and product C{sub 5}H were identified using photoionization spectroscopy. The ionization thresholds of C{sub 3}(X{sup 1}Σ{sub g}{sup +}) and C{sub 3}(a{sup 3}Π{sub u}) are determined as 11.6 ± 0.2 eV and 10.0 ± 0.2 eV, respectively. The C{sub 5}H product is identified as linear pentynylidyne that has an ionization energy 8.4 ± 0.2 eV. The title reaction releases translational energy 10.6 kcal mol{sup −1} in average and has an isotropic product angular distribution. The quantum-chemical calculation indicates that the C{sub 3}(a{sup 3}Π{sub u}) radical attacks one of the carbon atoms of C{sub 2}H{sub 2} and subsequently a hydrogen atom is ejected to form C{sub 5}H + H, in good agreement with the experimental observation. As far as we are aware, the C{sub 3}(a{sup 3}Π{sub u}) + C{sub 2}H{sub 2} reaction is investigated for the first time. This work gives an implication for the formation of C{sub 5}H from the C{sub 3}(a{sup 3}Π{sub u}) + C{sub 2}H{sub 2} reaction occurring in a combustion or discharge process of C{sub 2}H{sub 2}.

  11. Adventures on the C<sub>3sub>H>5sub>O potential energy surface: OH+propyne, OH+allene and related reactions

    SciTech Connect (OSTI)

    Zádor, Judit; Miller, James A.

    2014-06-25

    We mapped out the stationary points and the corresponding conformational space on the C<sub>3sub>H>5sub>O potential energy surface relevant for the OH + allene and OH + propyne reactions systematically and automatically using the KinBot software at the UCCSD(T)-F12b/cc-pVQZ-F12//M06-2X/6-311++G(d,p) level of theory. We used RRKM-based 1-D master equations to calculate pressure- and temperature-dependent, channel-specific phenomenological rate coefficients for the bimolecular reactions propyne + OH and allene + OH, and for the unimolecular decomposition of the CH<sub>3sub>CCHOH, CH<sub>3sub>C(OH)CH, CH<sub>2sub>CCH>2sub>OH, CH<sub>2sub>C(OH)CH>2sub> primary adducts, and also for the related acetonyl, propionyl, 2-methylvinoxy, and 3-oxo-1-propyl radicals. The major channel of the bimolecular reactions at high temperatures is the formation propargyl + H<sub>2sub>O, which makes the title reactions important players in soot formation at high temperatures. However, below ~1000 K the chemistry is more complex, involving the competition of stabilization, isomerization and dissociation processes. We found that the OH addition to the central carbon of allene has a particularly interesting and complex pressure dependence, caused by the low-lying exit channel to form ketene + CH<sub>3sub> bimolecular products. In this study, we compared our results to a wide range of experimental data and assessed possible uncertainties arising from certain aspects of the theoretical framework.

  12. Highly Flexible Self-Assembled V<sub>2sub>O>5sub> Cathodes Enabled by Conducting Diblock Copolymers

    SciTech Connect (OSTI)

    An, Hyosung; Mike, Jared; Smith, Kendall A.; Swank, Lisa; Lin, Yen-Hao; L. Pesek, Stacy; Verduzco, Rafael; Lutkenhaus, Jodie L.

    2015-09-22

    Mechanically robust battery electrodes are desired for applications in wearable devices, flexible displays, and structural energy and power. In this regard, the challenge is to balance mechanical and electrochemical properties in materials that are inherently brittle. Here, we demonstrate a unique water-based self-assembly approach that incorporates a diblock copolymer bearing electron- and ion-conducting blocks, poly(3-hexylthiophene)-block-poly(ethyleneoxide) (P3HT-b-PEO), with V<sub>2sub>O>5sub> to form a flexible, tough, carbon-free hybrid battery cathode. V<sub>2sub>O>5sub> is a promising lithium intercalation material, but it remains limited by its poor conductivity and mechanical properties. Our approach leads to a unique electrode structure consisting of interlocking V<sub>2sub>O>5sub> layers glued together with micellar aggregates of P3HT-b-PEO, which results in robust mechanical properties, far exceeding the those obtained from conventional fluoropolymer binders. Only 5 wt % polymer is required to triple the flexibility of V<sub>2sub>O>5sub>, and electrodes comprised of 10 wt % polymer have unusually high toughness (293 kJ/m3) and specific energy (530 Wh/kg), both higher than reduced graphene oxide paper electrodes. Furthermore, addition of P3HT-b-PEO enhances lithium-ion diffusion, eliminates cracking during cycling, and boosts cyclability relative to V<sub>2sub>O>5sub> alone. These results highlight the importance of tradeoffs between mechanical and electrochemical performance, where polymer content can be used to tune both aspects.

  13. Experimental oxygen potentials of U<sub>1-ysub>PryO>2± xsub> and thermodynamic assessment of the U-Pr-O system

    SciTech Connect (OSTI)

    McMurray, Jake W.; Silva, Chinthaka M.

    2015-12-09

    Thermogravimetric analysis (TGA) was used to determine the oxygen potentials of fluorite urania-praseodymia (U<sub>1-ysub>PryO>2± xsub>) solid solutions for y = 0.10 and 0.20 between 1000 and 1500 °C. A thermodynamic assessment of U-Pr-O system was performed using the CALPHAD (CALculation of PHAse Diagrams) method. Furthermore, the models well reproduce the TGA measurements and the computed phase relations are in good agreement with those proposed from an X-ray diffraction investigation.

  14. Keggin (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}H]xH{sub 2}O: Characterization and crystal structure

    SciTech Connect (OSTI)

    Bonfim, Rodrigo de Paiva Floro; Moura, Luiza Cristina de; Eon, Jean-Guillaume; Mentr, Olivier; Vezin, Herv; Caldarelli, Stefano

    2014-05-01

    Single crystals of the potassium salt (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}H]xH{sub 2}O of the vanadium tri-substituted ?-Keggin dodecatungstosilicate were prepared and analyzed by vibrational, EPR and {sup 51}V NMR spectroscopy. Varying the synthesis conditions allows crystallization of partially reduced anions. The crystal structure was determined for both oxidized (V{sup 5+}) and partially reduced (V{sup 4+/5+}) potassium salts. Single crystal X-ray diffraction data and solid state {sup 51}V-NMR spectra confirm the occurrence of a single vanadium site in a cubic structure due to rotational disorder of the Keggin ion. Partially reduced compounds crystallize within the same structure as fully oxidized ones. EPR experiments confirm strong interaction of V{sup 4+} with two V{sup 5+} ions, in accordance with insertion of a V{sub 3} subunit into the lacunary Keggin ion as designed in the synthesis method. The 3D-edifice is composed of K{sup +}/H{sub 2}O counter-sublattice with evidence of tunable water occupancy. - Graphical abstract: Relative arrangements of HPA clusters in (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}]xH{sub 2}O. - Highlights: We prepared single crystals of the potassium salt (K{sub 5}, H{sub 3}O)[SiV{sub 3}W{sub 9}O{sub 40}H]xH{sub 2}O. The synthesis was designed to give the ?-1,2,3-[SiV{sub 3}W{sub 9}O{sub 40}] Keggin ion. Strict pH control was necessary to avoid vanadium partial reduction. Reduced compounds crystallize within the same structure as fully oxidized ones. EPR confirms strong interaction of V{sup 4+} with two V{sup 5+} ions in a V{sub 3} subunit.

  15. Performance specifications for technology development: Application for characterization of volatile organic compounds in the environment

    SciTech Connect (OSTI)

    Carpenter, S.E.; Doskey, P.V.; Erickson, M.D.; Lindahl, P.C.

    1994-07-01

    This report contains information about technology development for the monitoring and remediation of environmental pollution caused by the release of volatile organic compounds. Topics discussed include: performance specification processes, gas chromatography, mass spectrometer, fiber-optic chemical sensors, infrared spectroscopy, Raman spectroscopy, piezoelectric sensors and electrochemical sensors. These methods are analyzed for their cost efficiency, accuracy, and the ability to meet the needs of the customer.

  16. Real-time monitoring of volatile organic compounds using chemical ionization mass spectrometry

    DOE Patents [OSTI]

    Mowry, Curtis Dale; Thornberg, Steven Michael

    1999-01-01

    A system for on-line quantitative monitoring of volatile organic compounds (VOCs) includes pressure reduction means for carrying a gaseous sample from a first location to a measuring input location maintained at a low pressure, the system utilizing active feedback to keep both the vapor flow and pressure to a chemical ionization mode mass spectrometer constant. A multiple input manifold for VOC and gas distribution permits a combination of calibration gases or samples to be applied to the spectrometer.

  17. Electron impact and chemical ionization mass spectral analysis of a volatile uranyl derivative

    SciTech Connect (OSTI)

    Reutter, D.J.; Hardy, D.R.

    1981-01-01

    Quadrupole mass spectral analysis of the volatile uranium ligand complex bis (1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) dioxouranium-di-n-butyl sulfoxide is described utilizing electron impact (EI) and methane chemical ionization (CI) ion sources. All major ions are tentatively identified and the potential usefulness of this complex for determining uranium isotope /sup 235/U//sup 238/U abundance is demonstrated.

  18. Nanoporous Al2O3 as a "Getter" for Volatile Radionuclides into

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nanostructued Glass-Ceramic Waste Forms - Energy Innovation Portal Nanoporous Al2O3 as a "Getter" for Volatile Radionuclides into Nanostructued Glass-Ceramic Waste Forms Sandia National Laboratories Contact SNL About This Technology Publications: PDF Document Publication Market Sheet (738 KB) Technology Marketing SummaryThe first phase of this project is capture and encapsulation which is achieved by using nanoporous alumina to confine gaseous iodine, for example, from fission or

  19. Implications of changing correlations between WTI and other commodities, asset classes, and implied volatility

    U.S. Energy Information Administration (EIA) Indexed Site

    Implications of changing correlations between WTI and other commodities, asset classes, and implied volatility James Preciado October 2012 Independent Statistics & Analysis www.eia.gov U.S. Energy Information Administration Washington, DC 20585 This paper is released to encourage discussion and critical comment. The analysis and conclusions expressed here are those of the authors and not necessarily those of the U.S. Energy Information Administration. WORKING PAPER SERIES October 2012 James

  20. The role of non-volatile memory from an application perspective

    SciTech Connect (OSTI)

    Kettering, Brett M; Nunez, James A

    2010-09-16

    Current, emerging, and future NVM (non-volatile memory) technologies give us hope that we will be able to architect HPC (high performance computing) systems that initially use them in a memory and storage hierarchy, and eventually use them as the memory and storage for the system, complete with ownership and protections as a HDD-based (hard-disk-drive-based) file system provides today.

  1. FDATMOS16 non-linear partitioning and organic volatility distributions in urban aerosols

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Madronich, Sasha; Kleinman, Larry; Conley, Andrew; Lee-Taylor, Julie; Hodzic, A.; Aumont, Bernard

    2015-12-17

    Gas-to-particle partitioning of organic aerosols (OA) is represented in most models by Raoult’s law, and depends on the existing mass of particles into which organic gases can dissolve. This raises the possibility of non-linear response of particle-phase OA to the emissions of precursor volatile organic compounds (VOCs) that contribute to this partitioning mass. Implications for air quality management are evident: A strong non-linear dependence would suggest that reductions in VOC emission would have a more-than-proportionate benefit in lowering ambient OA concentrations. Chamber measurements on simple VOC mixtures generally confirm the non-linear scaling between OA and VOCs, usually stated as amore » mass-dependence of the measured OA yields. However, for realistic ambient conditions including urban settings, no single component dominates the composition of the organic particles, and deviations from linearity are presumed to be small. Here we re-examine the linearity question using volatility spectra from several sources: (1) chamber studies of selected aerosols, (2) volatility inferred for aerosols sampled in two megacities, Mexico City and Paris, and (3) an explicit chemistry model (GECKO-A). These few available volatility distributions suggest that urban OA may be only slightly super-linear, with most values of the sensitivity exponent in the range 1.1-1.3, also substantially lower than seen in chambers for some specific aerosols. Furthermore, the rather low values suggest that OA concentrations in megacities are not an inevitable convergence of non-linear effects, but can be addressed (much like in smaller urban areas) by proportionate reductions in emissions.« less

  2. New hypodiphosphates of the alkali metals: Synthesis, crystal structure and vibrational spectra of the hypodiphosphates(IV) M{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (M=Rb and Cs)

    SciTech Connect (OSTI)

    Wu, Peng; Wiegand, Thomas; Eckert, Hellmut

    2012-10-15

    The new hypodiphosphates(IV) Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (1) and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (2) were synthesized by soft chemistry reactions from aqueous solutions of hypophosphoric acid and the corresponding heavy alkali-metal carbonates. Their crystal structures were determined by single crystal X-ray diffraction. Both compounds crystallize isotypic in the triclinic space group P-1 with one formula unit in the unit cell. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units in staggered conformation for the P{sub 2}O{sub 6} skeleton and the corresponding alkali-metal cations. In the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} ion the hydrogen atoms are in a 'trans-trans' conformation. O{center_dot}H-O hydrogen bonds between the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups consolidate the structures into a three-dimensional network. The FT-Raman and {sup 31}P and {sup 1}H and MAS NMR spectra of the title compounds have been recorded and interpreted, especially with respect to their assignment to the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups. Thermogravimetric data of 2 have been interpreted in terms of a thermal decomposition model. - Graphical Abstract: The layered compounds Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] have been synthesized and investigated. Both crystallize isotypic. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units and the corresponding alkali-metal cations. Highlights: Black-Right-Pointing-Pointer Synthesis and single-crystal structure of new alkali hypodiphosphates. Black-Right-Pointing-Pointer Structures are characterized by [(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})]{sup 2-} units and M{sup +} cations. Black-Right-Pointing-Pointer (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units are linked by short hydrogen bonds. Black-Right-Pointing-Pointer Both compounds are characterized by {sup 31}P MAS-NMR spectra.

  3. Melt processing of the Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub y] superconductor in oxygen and argon atmospheres

    SciTech Connect (OSTI)

    Holesinger, T.G.; Miller, D.J. ); Chumbley, L.S. )

    1992-08-01

    Solidification and subsequent annealing of Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub y] (2212) in oxygen and argon atmospheres were investigated in order to identify alternative processing routes for controlling microstructures and superconducting properties. In addition to 2212, several other phases formed on cooling in O[sub 2] and did not disappear upon subsequent annealing. Crystallization in Ar resulted in a divorced eutetic structure of Bi[sub 2]Sr[sub 3-x]Ca[sub x]O[sub y] and Cu[sub 2]O/CuO. The superconductor was formed on subsequent anneals. Samples melted in Ar and then annealed generally possessed a more uniform microstructure compared with samples that were melted in oxygen and annealed. Compositional measurements of the 2212 phase suggest that CaO segregation in the melt may be minimized with an overall composition such as Bi[sub 2.15]Sr[sub 2]Ca[sub 0.85]Cu[sub 2]O[sub y].

  4. Melt processing of the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} superconductor in oxygen and argon atmospheres

    SciTech Connect (OSTI)

    Holesinger, T.G.; Miller, D.J.; Chumbley, L.S.

    1992-08-01

    Solidification and subsequent annealing of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} (2212) in oxygen and argon atmospheres were investigated in order to identify alternative processing routes for controlling microstructures and superconducting properties. In addition to 2212, several other phases formed on cooling in O{sub 2} and did not disappear upon subsequent annealing. Crystallization in Ar resulted in a divorced eutetic structure of Bi{sub 2}Sr{sub 3-x}Ca{sub x}O{sub y} and Cu{sub 2}O/CuO. The superconductor was formed on subsequent anneals. Samples melted in Ar and then annealed generally possessed a more uniform microstructure compared with samples that were melted in oxygen and annealed. Compositional measurements of the 2212 phase suggest that CaO segregation in the melt may be minimized with an overall composition such as Bi{sub 2.15}Sr{sub 2}Ca{sub 0.85}Cu{sub 2}O{sub y}.

  5. Properties measurements of (U{sub 0.7}Pu{sub 0.3})O{sub 2-x} in PO{sub 2}-controlled atmosphere

    SciTech Connect (OSTI)

    Kato, M.; Murakami, T.; Sunaoshi, T.; Nelson, A.T.; McClellan, K.J.

    2013-07-01

    The investigation of physical properties of uranium and plutonium mixed oxide (MOX) fuels is important for the development of fast reactor fuels. It is well known that MOX is a nonstoichiometric oxide, and the physical properties change drastically with the Oxygen-to-Metal (O/M) ratio. A control technique for O/M ratio was established for measurements of high temperature properties of uranium and plutonium mixed oxide fuels. Sintering behavior, thermal expansion and O/M change of (U{sub 0.7}Pu{sub 0.3})O{sub 2.00} and (U{sub 0.7}Pu{sub 0.3})O{sub 1.99} were investigated in PO{sub 2}-controlled atmosphere which was controlled by H{sub 2}/H{sub 2}O gas system. Sintering behavior changed drastically with O/M ratio, and shrinkage of (U{sub 0.7}Pu{sub 0.3})O{sub 2.00} was faster and more advanced at lower temperatures as compared with (U{sub 0.7}Pu{sub 0.3})O{sub 1.99}. Thermal expansion was observed to be slightly increased with decreasing O/M ratio. (authors)

  6. Magnetic, dielectric, and magnetoelectric properties in Sr{sub 2}CoGe{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Song, Y. Q.; Li, Q.; Zhou, W. P.; Cao, Q. Q.; Wang, D. H. Du, Y. W.; Zhang, Z. M.; Xu, Q. Y.

    2015-05-07

    We investigate the magnetoelectric effect in Sr{sub 2}CoGe{sub 2}O{sub 7}, which has a two-dimensional magnetic interaction between Co ions in the ab plane. This compound shows a weak magnetism and field-induced magnetic transition below the temperature of 7?K. It does not exhibit electric polarization under zero magnetic field. However, by applying an external magnetic field, the electric polarization is induced around its Nel temperature and increases with increasing magnetic field. The induced electric polarization in Sr{sub 2}CoGe{sub 2}O{sub 7} is almost two orders of magnitude smaller than that of Ba{sub 2}CoGe{sub 2}O{sub 7}. This result suggests that the different ionic radius of the strontium and the barium anion plays a key role in determining the property of electric polarization. The origins of electric polarization and magnetoelectric effect are discussed.

  7. Formation and aging of secondary organic aerosol from toluene: changes in chemical composition, volatility, and hygroscopicity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hildebrandt Ruiz, L.; Paciga, A. L.; Cerully, K. M.; Nenes, A.; Donahue, N. M.; Pandis, S. N.

    2015-07-24

    Secondary organic aerosol (SOA) is transformed after its initial formation, but this chemical aging of SOA is poorly understood. Experiments were conducted in the Carnegie Mellon environmental chamber to form secondary organic aerosol (SOA) from the photo-oxidation of toluene and other small aromatic volatile organic compounds (VOCs) in the presence of NOx under different oxidizing conditions. The effects of the oxidizing condition on organic aerosol (OA) composition, mass yield, volatility, and hygroscopicity were explored. Higher exposure to the hydroxyl radical resulted in different OA composition, average carbon oxidation state (OSc), and mass yield. The OA oxidation state generally increased duringmore » photo-oxidation, and the final OA OSc ranged from -0.29 to 0.16 in the performed experiments. The volatility of OA formed in these different experiments varied by as much as a factor of 30, demonstrating that the OA formed under different oxidizing conditions can have a significantly different saturation concentration. There was no clear correlation between hygroscopicity and oxidation state for this relatively hygroscopic SOA.« less

  8. New model for thermal volatilization of solid particles undergoing flash-pyrolysis

    SciTech Connect (OSTI)

    Villermaux, J.; Antoine, B.; Lede, J.; Soulignac, F.

    1983-01-01

    Many industrial processes involve the consumption of solid particles immersed in a reacting medium. Among these, the gasification of coal and biomass in fixed, fluidized or moving beds is of special interest. A great number of models describing gas-solid reactions can be found in the literature. Models dealing with the thermal volatilization of a solid controlled by heat transfer between the surrounding medium and the inner volume of the particle are more scarce. In addition, existing models often rely on the concept of a surface reaction, which is questionable, because deeper layers also contribute to the reaction as heat penetrates into the solid. A new model is proposed describing the volatilization of a solid by thermal penetration. This model was initially imagined for interpreting flash-pyrolysis of sawdust particles. Actually, it could be applied to any kind of solid reactions where volatilization is controlled by heat conduction from the outer surface. Only a few preliminary but significant results are presented in this paper. (Refs. 6)>

  9. New model for thermal volatilization of solid particles undergoing flash-pyrolysis

    SciTech Connect (OSTI)

    Villermaux, J.; Antoine, B.; Lede, J.; Soulignac, F.

    1983-01-01

    Many industrial processes involve the consumption of solid particles immersed in a reacting medium. Among these, the gasification of coal and biomass in fixed, fluidized or moving beds is of special interest. A great number of models describing gas-solid reactions can be found in the literature. Models dealing with the thermal volatilization of a solid controlled by heat transfer between the surrounding medium and the inner volume of the particle are more scarce. In addition, existing models often rely on the concept of a ''surface reaction'', which is questionable, because deeper layers also contribute to the reaction as heat penetrates into the solid. A new model is proposed describing the volatilization of a solid by thermal penetration. This model was initially imagined for interpreting flash-pyrolysis of sawdust particles. Actually, it could be applied to any kind of solid reactions where volatilization is controlled by heat conduction from the outer surface. Only a few preliminary but significant results are presented in this paper. (6 figs., 6 refs.)

  10. High-temperature phase transformation and topochemical nature in ferroelastic (NH{sub 4}){sub 2}SO{sub 4}

    SciTech Connect (OSTI)

    Lee, Kwang-Sei; Oh, In-Hwan; Ko, Jae-Hyeon

    2014-04-01

    The electrical conductivity of ferroelastic ammonium sulfate (NH{sub 4}){sub 2}SO{sub 4} revealed an anomaly at around 130 C (=403 K, T{sub P}) on heating with large and irreversible thermal hysteresis through thermal cycle. Ferroelastic domain walls and surface morphology of (NH{sub 4}){sub 2}SO{sub 4} were investigated by hot-stage polarizing microscopy. Structural phase transition from an orthorhombic ferroelastic phase to a hexagonal paraelastic phase was not identified at T{sub P} upon heating. On further heating above T{sub P}, microscopic spots appeared and grew on the crystal surface, suggesting that the high-temperature anomaly at T{sub P} was an indication of an onset of thermal decomposition controlled by topochemical factors. The increase of electrical conductivity above T{sub P} was attributed to proton migration. - Graphical abstract: Surface morphology of the (100) face of (NH{sub 4}){sub 2}SO{sub 4} on heating, showing chemical reaction at the surface. - Highlights: We investigate the high-temperature phase transformation of ammonium sulfate. The increasing conductivity upon heating is attributed to proton migration. Structural phase transition from orthorhombic to hexagonal phase is not confirmed. High-temperature anomaly is related to an onset of thermal decomposition. The nature of the high-temperature anomaly is topochemical controlled by defects.

  11. Fuel cell sub-assembly

    DOE Patents [OSTI]

    Chi, Chang V.

    1983-01-01

    A fuel cell sub-assembly comprising a plurality of fuel cells, a first section of a cooling means disposed at an end of the assembly and means for connecting the fuel cells and first section together to form a unitary structure.

  12. Scintillator having a MgAI.sub.2O.sub.4 host lattice

    DOE Patents [OSTI]

    Chen, Ching-Fong

    2011-12-20

    A scintillator having a host lattice of MgAl.sub.2O.sub.4 was prepared by hot pressing under a vacuum environment a powder mixture of MgAl.sub.2O.sub.4, CeO.sub.2, and LiF.

  13. Discharge Performance of Li-O<sub>2sub> Batteries Using a Multiscale Modeling Approach

    SciTech Connect (OSTI)

    Bao, Jie; Xu, Wu; Bhattacharya, Priyanka; Stewart, Mark L.; Zhang, Jiguang; Pan, Wenxiao

    2015-06-10

    To study the discharge performance of Li–O<sub>2sub> batteries, we propose a multiscale modeling framework that links models in an upscaling fashion from the nanoscale to mesoscale and finally to the device scale. We have effectively reconstructed the microstructure of a Li–O<sub>2sub> air electrode in silico, conserving the porosity, surface-to-volume ratio, and pore size distribution of the real air electrode structure. The mechanism of rate-dependent morphology of Li<sub>2sub>O>2sub> growth is incorporated into the mesoscale model. The correlation between the active-surface-to-volume ratio and averaged Li<sub>2sub>O>2sub> concentration is derived to link different scales. The proposed approach’s accuracy is first demonstrated by comparing the predicted discharge curves of Li–O<sub>2sub> batteries with experimental results at the high current density. Next, the validated modeling approach effectively captures the significant improvement in discharge capacity due to the formation of Li<sub>2sub>O>2sub> particles. Finally, it predicts the discharge capacities of Li–O<sub>2sub> batteries with different air electrode microstructure designs and operating conditions.

  14. Uncatalysed and catalysed soot combustion under NO{sub x} + O{sub 2}: Real diesel versus model soots

    SciTech Connect (OSTI)

    Atribak, I.; Bueno-Lopez, A.; Garcia-Garcia, A.

    2010-11-15

    In this work, the uncatalysed and catalysed combustion of two commercial carbon blacks and three diesel soot samples were analysed and related to the physico-chemical properties of these carbon materials. Model soot samples are less reactive than real soot samples, which can be attributed, mainly, to a lower proportion in heteroatoms and a higher graphitic order for the case of one of the carbon blacks. Among the diesel soot samples tested, the most relevant differences are the volatile matter/fixed carbon contents, which are directly related to the engine operating conditions (idle or loaded) and to the use of an oxidation catalyst or not in the exhaust. The soot collected after an oxidation catalyst (A-soot) is more reactive than the counterpart virgin soot obtained under the same engine operating modes but before the oxidation catalyst. The reactivity of the different soot samples follows the same trend under uncatalysed and catalysed combustion, the combustion profiles being always shifted towards lower temperatures for the catalysed reactions. The differences between the soot samples become less relevant in the presence of a catalyst. The ceria-zirconia catalysts tested are very effective not only to oxidise soot but also to combust the soluble organic fraction emitted at low temperatures. The most reactive soot (A-soot) exhibits a T{sub 50%} parameter of 450 C when using the most active catalyst. (author)

  15. High temperature thermoelectric properties of the solid-solution zintl phase Eu₁₁Cd<sub>6-xsub>Znx>Sb₁₂

    SciTech Connect (OSTI)

    Kazem, Nasrin; Hurtado, Antonio; Sui, Fan; Ohno, Saneyuki; Zevalkink, Alexandra; Snyder, Jeffrey G.; Kauzlarich, Susan M.

    2015-08-24

    Solid-solution Zintl compounds with the formulaEu₁₁Cd<sub>6-xsub>Znx>Sb₁₂ have been synthesized from the elements as single crystals using a tin flux according to the stoichiometry Eu:Cd:Zn:Sb:Sn of 11:6–x<sub>p:xp>:12:30 with x<sub>p> = 0, 1, 2, 3, 4, 5, and 6, where x<sub>p> is the preparative amount of Zn employed in the reaction. The crystal structures and the compositions were established by single-crystal as well as powder X-ray diffraction and wavelength-dispersive X-ray analysis measurements. The title solid-solution Zintl compounds crystallize isostructurally in the centrosymmetric monoclinic space group C 2/m (No. 12, Z = 2) as the Sr₁₁Cd₆Sb₁₂ structure type (Pearson symbol mC58). There is a miscibility gap at 3 ≤ x<sub>p> ≤ 4 where the major product crystallizes in a disordered structure related to the Ca₉Mn₄Bi₉ structure type; otherwise, for all other compositions, the Sr₁₁Cd₆Sb₁₂ structure is the majority phase. Eu₁₁Cd₆Sb₁₂ shows lower lattice thermal conductivity relative to Eu₁₁Zn₆Sb₁₂ consistent with its higher mean atomic weight, and as anticipated, the solid-solution samples of Eu₁₁Cd<sub>6–xsub>Znx>Sb₁₂ have effectively reduced lattice thermal conductivities relative to the end member compounds. Eu₁₁̣̣₀<sub>(1)sub>Cd₄̣̣₅>(2)sub>Zn₁̣̣₅>(2)sub>Sb₁₂̣̣₀>(1)sub> exhibits the highest zT value of >0.5 at around 800 K which is twice as large as the end member compounds.

  16. Thermodynamic analysis of binary Fe{sub 85}B{sub 15} to quinary Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloys for primary crystallizations of α-Fe in nanocrystalline soft magnetic alloys

    SciTech Connect (OSTI)

    Takeuchi, A. Zhang, Y.; Takenaka, K.; Makino, A.

    2015-05-07

    Fe-based Fe{sub 85}B{sub 15}, Fe{sub 84}B{sub 15}Cu{sub 1}, Fe{sub 82}Si{sub 2}B{sub 15}Cu{sub 1}, Fe{sub 85}Si{sub 2}B{sub 12}Cu{sub 1}, and Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} (NANOMET{sup ®}) alloys were experimental and computational analyzed to clarify the features of NANOMET that exhibits high saturation magnetic flux density (B{sub s}) nearly 1.9 T and low core loss than conventional nanocrystalline soft magnetic alloys. The X-ray diffraction analysis for ribbon specimens produced experimentally by melt spinning from melts revealed that the samples were almost formed into an amorphous single phase. Then, the as-quenched samples were analyzed with differential scanning calorimeter (DSC) experimentally for exothermic enthalpies of the primary and secondary crystallizations (ΔH{sub x1} and ΔH{sub x2}) and their crystallization temperatures (T{sub x1} and T{sub x2}), respectively. The ratio ΔH{sub x1}/ΔH{sub x2} measured by DSC experimentally tended to be extremely high for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy, and this tendency was reproduced by the analysis with commercial software, Thermo-Calc, with database for Fe-based alloys, TCFE7 for Gibbs free energy (G) assessments. The calculations exhibit that a volume fraction (V{sub f}) of α-Fe tends to increase from 0.56 for the Fe{sub 85}B{sub 15} to 0.75 for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy. The computational analysis of the alloys for G of α-Fe and amorphous phases (G{sub α-Fe} and G{sub amor}) shows that a relationship G{sub α-Fe} ∼ G{sub amor} holds for the Fe{sub 85}Si{sub 2}B{sub 12}Cu{sub 1}, whereas G{sub α-Fe} < G{sub amor} for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy at T{sub x1} and that an extremely high V{sub f} = 0.75 was achieved for the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy by including 2.8 at. % Si and 4.5 at. % P into α-Fe. These computational results indicate that the Fe{sub 85}Si{sub 2}B{sub 8}P{sub 4}Cu{sub 1} alloy barely forms amorphous phase, which, in turn, leads to high V{sub f} and resultant high B{sub s}.

  17. Epitaxial patterning of nanometer-thick Y{sub 3}Fe{sub 5}O{sub 12} films

    Office of Scientific and Technical Information (OSTI)

    with low magnetic damping. (Journal Article) | SciTech Connect Epitaxial patterning of nanometer-thick Y{sub 3}Fe{sub 5}O{sub 12} films with low magnetic damping. Citation Details In-Document Search Title: Epitaxial patterning of nanometer-thick Y{sub 3}Fe{sub 5}O{sub 12} films with low magnetic damping. Magnetic insulators such as yttrium iron garnet, Y3Fe5O12, with extremely low magnetic damping have opened the door for low power spin-orbitronics due to their low energy dissipation and

  18. Pr{sub 1.33}Pt{sub 4}Ga{sub 10}: Superstructure and magnetism

    SciTech Connect (OSTI)

    Doan Nguyen, Sau; Ryan, Kevin; Chai, Ping; Shatruk, Michael; Xin, Yan; Chapman, Karena W.; Chupas, Peter J.; Fronczek, Frank R.; Macaluso, Robin T.

    2014-12-15

    Pr{sub 1.33}Pt{sub 4}Ga{sub 10} crystals were prepared by Ga-flux method. The superstructure of this compound was studied by single-crystal X-ray diffraction (XRD), transmission electron microscopy (TEM), and diffuse X-ray scattering. Pr{sub 1.33}Pt{sub 4}Ga{sub 10} adopts the P6{sub 3}/mmc space group with a=b=4.3227(5) Å, c=16.485(3) Å: the structure features Pr{sub 2}Ga{sub 3} layers alternating with Pt{sub 2}Ga{sub 4} layers along the c-axis. TEM studies and pair distribution function (PDF) analysis of X-ray total scattering data show that Pr{sub 2}Ga{sub 3} layers possess an ordered superstructure (of dimension a′=a√(3)) in which Pr vacancies and Ga atoms are ordered within the ab-plane but disordered along the c-direction. PDF analysis also shows temperature-dependent structural features local to the Pr{sup 3+} ion. Magnetic measurements reveal that Pr{sup 3+} ions order ferrimagnetically below 12.5(2) K. - Graphical abstract: Left: Crystal structure of Pr{sub 1.33}Pt{sub 4}Ga{sub 10} showing Pr and Ga vacancies in the Pr{sub 2}Ga{sub 3} plane. Right: Tunneling electron microscopy (TEM) image of Pr{sub 1.33}Pt{sub 4}Ga{sub 10}. These vacancies have been studied using TEM and pair distribution function analysis. Magnetic measurements reveal that Pr{sup 3+} ions order ferrimagnetically below 7.8(2) K. - Highlights: • TEM studies indicate a superstructure from Pr and Ga vacancies. • Pair distribution function analyses may point to structural relaxation of vacancies. • Pr{sub 1.33}Pt{sub 4}Ga{sub 10} behaves as a ferromagnet and exhibits a metamagnetic transition.

  19. Method of producing superconducting fibers of YBa[sub 2]Cu[sub 3]O[sub x

    DOE Patents [OSTI]

    Schwartzkopf, L.A.; Ostenson, J.E.; Finnemore, D.K.

    1990-11-13

    Fibers of YBa[sub 2]Cu[sub 3]O[sub x] have been produce by pendant drop melt extraction. This technique involves the end of a rod of YBa[sub 2]Cu[sub 3]O[sub x] melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 10 cm in length with the usual lateral dimensions, ranging from 20 [mu]m to 125 [mu]m. The fibers require a heat treatment to make them superconducting.

  20. A Linear trans -Bis(imido) Neptunium(V) Actinyl Analog: NpV (NDipp)<sub>2sub> ( tBu<sub>2sub> bipy)<sub>2sub>Cl (Dipp = 2,6- i Pr<sub>2sub>C>6sub>H>3sub>)

    SciTech Connect (OSTI)

    Brown, Jessie L.; Batista, Enrique R.; Boncella, James M.; Gaunt, Andrew J.; Reilly, Sean D.; Scott, Brian L.; Tomson, Neil C.

    2015-07-22

    We present the discovery that imido analogs of actinyl dioxo cations can be extended beyond uranium into the transuranic elements. Synthesis of the Np(V) complex, Np(NDipp)<sub>2sub>(tBu>2sub>bipy)>2sub>Cl (1), is achieved through treatment of a Np(IV) precursor with a bipyridine co-ligand and lithium-amide reagent. Complex 1 has been structurally characterized, analyzed by 1H NMR and UV/vis/NIR spectroscopies, and the electronic structure evaluated by DFT calculations.

  1. Effect of SO<sub>2sub> on oxidation of metallic materials in CO<sub>2sub>/H>2sub>O-rich gases relevant to oxyfuel environments

    SciTech Connect (OSTI)

    Huczkowski, P.; Olszewski, T.; Schiek, M.; Lutz, B.; Holcomb, G.; Shemet, V.; Meier, G. H.; Singheiser, L.; Quadakkers, W. J.

    2012-09-19

    This report is a description of research performed by the Jlich Research Centre. Their conclusions outline the effects of SO<sub>2sub> additions on oxide formations and the interaction of other gases in oxvyfuel environments.

  2. Transverse thermoelectric effect in La{sub 0.67}Sr{sub 0.33}MnO{sub 3}|SrRuO{sub 3} superlattices

    SciTech Connect (OSTI)

    Shiomi, Y.; Handa, Y.; Kikkawa, T.; Saitoh, E.

    2015-06-08

    Transverse thermoelectric effects in response to an out-of-plane heat current have been studied in an external magnetic field for ferromagnetic superlattices consisting of La{sub 0.67}Sr{sub 0.33}MnO{sub 3} and SrRuO{sub 3} layers. The superlattices were fabricated on SrTiO{sub 3} substrates by pulsed laser deposition. We found that the sign of the transverse thermoelectric voltage for the superlattices is opposite to that for La{sub 0.67}Sr{sub 0.33}MnO{sub 3} and SrRuO{sub 3} single layers at 200?K, implying an important role of spin Seebeck effects inside the superlattices. At 10?K, the magnetothermoelectric curves shift from the zero field due to an antiferromagnetic coupling between layers in the superlattices.

  3. Combustion synthesized nanocrystalline Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode for lithium-ion batteries

    SciTech Connect (OSTI)

    Nathiya, K.; Bhuvaneswari, D.; Gangulibabu; Kalaiselvi, N.

    2012-12-15

    Graphical abstract: Nanocrystalline Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C compound has been synthesized using a novel corn assisted combustion (CAC) method, wherein the composite prepared at 850 °C is found to exhibit superior physical and electrochemical properties than the one synthesized at 800 °C (Fig. 1). Despite the charge disproportionation of V{sup 4+} and a possible solid solution behavior of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} cathode upon insertion and de-insertion of Li{sup +} ions, the structural stability of the same is appreciable, even with the extraction of third lithium at 4.6 V (Fig. 2). An appreciable specific capacity of 174 mAh g{sup −1} with an excellent columbic efficiency (99%) and better capacity retention upon high rate applications have been exhibited by Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode, thus demonstrating the feasibility of CAC method in preparing the title compound to best suit with the needs of lithium battery applications. Display Omitted Highlights: ► Novel corn assisted combustion method has been used to synthesize Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C. ► Corn is a cheap and eco benign combustible fuel to facilitate CAC synthesis. ► Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C exhibits an appreciable specific capacity of 174 mAh g{sup −1} (C/10 rate). ► Currently observed columbic efficiency of 99% is better than the reported behavior. ► Suitability of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode up to 10C rate is demonstrated. -- Abstract: Nanocrystalline Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C composite synthesized using a novel corn assisted combustion method at 850 °C exhibits superior physical and electrochemical properties than the one synthesized at 800 °C. Despite the charge disproportionation of V{sup 4+} and a possible solid solution behavior of Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} cathode upon insertion and extraction of Li{sup +} ions, the structural stability of the same is appreciable, even with the extraction of third lithium at 4.6 V. An appreciable specific capacity of 174 mAh g{sup −1} and better capacity retention upon high rate applications have been exhibited by Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C cathode, thus demonstrating the suitability of the same for lithium-ion battery applications.

  4. Thickness dependence of magnetoelectric response for composites of Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films on CoFe{sub 2}O{sub 4} ceramic substrates

    SciTech Connect (OSTI)

    Wang, Jing Zhu, Kongjun; Wu, Xia; Deng, Chaoyong; Peng, Renci; Wang, Jianjun

    2014-08-15

    Using chemical solution spin-coating we grew Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} films of different thicknesses on highly dense CoFe{sub 2}O{sub 4} ceramics. X-ray diffraction revealed no other phases except Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} and CoFe{sub 2}O{sub 4}. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} film was important in obtaining strong magnetoelectric coupling.

  5. Thermodynamics of CoAl{sub 2}O{sub 4}-CoGa{sub 2}O{sub 4} solid solutions

    SciTech Connect (OSTI)

    Lilova, Kristina I.; Navrotsky, Alexandra; Melot, Brent C.; Seshadri, Ram

    2010-06-15

    CoAl{sub 2}O{sub 4}, CoGa{sub 2}O{sub 4}, and their solid solution Co(Ga{sub z}Al{sub 1-z}){sub 2}O{sub 4} have been studied using high temperature oxide melt solution calorimetry in molten 2PbO.B{sub 2}O{sub 3} at 973 K. There is an approximately linear correlation between lattice parameters, enthalpy of formation from oxides, and the Ga content. The experimental enthalpy of mixing is zero within experimental error. The cation distribution parameters are calculated using the O'Neill and Navrotsky thermodynamic model. The enthalpies of mixing calculated from these parameters are small and consistent with the calorimetric data. The entropies of mixing are calculated from site occupancies and compared to those for a random mixture of Ga and Al ions on octahedral site with all Co tetrahedral and for a completely random mixture of all cations on both sites. Despite a zero heat of mixing, the solid solution is not ideal in that activities do not obey Raoult's Law because of the more complex entropy of mixing. - Graphical abstract: Measured enthalpies of mixing of CoAl{sub 2}O{sub 4}-CoGa{sub 2}O{sub 4} solid solutions are close to zero but entropies of mixing reflect the complex cation distribution, so the system is not an ideal solution.

  6. Location of trivalent lanthanide dopant energy levels in (Lu{sub 0.5}Gd{sub 0.5}){sub 2}O{sub 3}

    SciTech Connect (OSTI)

    Retot, H.; Viana, B.; Bessiere, A.; Galtayries, A.

    2011-06-15

    The location of Ln{sup 3+} dopant energy levels relative to bands in (Lu{sub 0.5}Gd{sub 0.5}){sub 2}O{sub 3} was studied. A several-steps analysis of XPS measurements on heavy lanthanides sesquioxides Ln{sub 2}O{sub 3} (Ln = Gd, Tb, Dy, Er, Tm, Yb, Lu) and on Sc{sub 2}O{sub 3} and Y{sub 2}O{sub 3} reference materials were used to locate Ln{sup 3+} dopant ground state relative to the top of the valence band in (Lu{sub 0.5}Gd{sub 0.5}){sub 2}O{sub 3} within an error bar of {+-}0.4 eV. The agreement between XPS data and model was found improved relative to previous studies. When compared to XPS analysis, prediction based on optical absorption shows a slight underestimation attributed to the lack of precision in Ce{sup 4+} charge transfer band measurement.

  7. Blending Cr<sub>2sub>O>3sub> into a NiO-Ni electrocatalyst for sustained water splitting

    SciTech Connect (OSTI)

    Gong, Ming; Zhou, Wu; Kenney, Michael James; Kapusta, Rich; Cowley, Sam; Wu, Yingpeng; Lu, Bingan; Lin, Meng -Chang; Wang, Di -Yan; Yang, Jiang; Hwang, Bing -Joe; Dai, Hongjie

    2015-08-24

    The rising H<sub>2sub> economy demands active and durable electrocatalysts based on low-cost, earth-abundant materials for water electrolysis/photolysis. Here we report nanoscale Ni metal cores over-coated by a Cr<sub>2sub>O>3sub>-blended NiO layer synthesized on metallic foam substrates. The Ni@NiO/Cr<sub>2sub>O>3sub> triphase material exhibits superior activity and stability similar to Pt for the hydrogen-evolution reaction in basic solutions. The chemically stable Cr<sub>2sub>O>3sub> is crucial for preventing oxidation of the Ni core, maintaining abundant NiO/Ni interfaces as catalytically active sites in the heterostructure and thus imparting high stability to the hydrogen-evolution catalyst. The highly active and stable electrocatalyst enables an alkaline electrolyzer operating at 20 mA cm2 at a voltage lower than 1.5 V, lasting longer than 3 weeks without decay. Thus, the non-precious metal catalysts afford a high efficiency of about 15 % for light-driven water splitting using GaAs solar cells.

  8. Constructing hierarchical interfaces: TiO<sub>2sub>-supported PtFe-FeO<sub>x> nanowires for room temperature CO oxidation

    SciTech Connect (OSTI)

    Zhu, Huiyuan; Wu, Zili; Dong, Su; Veith, Gabriel M.; Lu, Hanfeng; Zhang, Pengfei; Chai, Song -Hai; Dai, Sheng

    2015-08-05

    This is a report of a facile approach to constructing catalytic active hierarchical interfaces in one-dimensional (1D) nanostructure, exemplified by the synthesis of TiO<sub>2sub>-supported PtFe–FeO<sub>x> nanowires (NWs). The hierarchical interface, constituting atomic level interactions between PtFe and FeO<sub>x> within each NW and the interactions between NWs and support (TiO<sub>2sub>), enables CO oxidation with 100% conversion at room temperature. We identify the role of the two interfaces by probing the CO oxidation reaction with isotopic labeling experiments. Both the oxygen atoms (Os) in FeO<sub>x> and TiO<sub>2sub> participate in the initial CO oxidation, facilitating the reaction through a redox pathway. Moreover, the intact 1D structure leads to the high stability of the catalyst. After 30 h in the reaction stream, the PtFe–FeO<sub>x>/TiO2 catalyst exhibits no activity decay. These results provide a general approach and new insights into the construction of hierarchical interfaces for advanced catalysis.

  9. Band alignment and electrical properties of Al{sub 2}O{sub 3}/?-Ga{sub 2}O{sub 3} heterojunctions

    SciTech Connect (OSTI)

    Kamimura, Takafumi Hoi Wong, Man; Krishnamurthy, Daivasigamani; Higashiwaki, Masataka; Sasaki, Kohei; Kuramata, Akito; Yamakoshi, Shigenobu; Masui, Takekazu

    2014-05-12

    The band alignment of Al{sub 2}O{sub 3}/n-Ga{sub 2}O{sub 3} was investigated by x-ray photoelectron spectroscopy (XPS). With a band gap of 6.8??0.2?eV measured for Al{sub 2}O{sub 3}, the conduction and valence band offsets at the interface were estimated to be 1.5??0.2?eV and 0.7??0.2?eV, respectively. The conduction band offset was also obtained from tunneling current in Al{sub 2}O{sub 3}/n-Ga{sub 2}O{sub 3} (2{sup }01) metal-oxide-semiconductor (MOS) diodes using the Fowler-Nordheim model. The electrically extracted value was in good agreement with the XPS data. Furthermore, the MOS diodes exhibited small capacitance-voltage hysteresis loops, indicating the successful engineering of a high-quality Al{sub 2}O{sub 3}/Ga{sub 2}O{sub 3} interface.

  10. Efficient electrochemical CO<sub>2sub> conversion powered by renewable energy

    SciTech Connect (OSTI)

    Kauffman, Douglas R.; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R.; Zeng, Chenjie; Jin, Rongchao

    2015-06-29

    The catalytic conversion of CO<sub>2sub> into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO<sub>2sub> conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO<sub>2sub> conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au<sub>25sub> nanoclusters as renewably powered CO<sub>2sub> conversion electrocatalysts with CO<sub>2sub> → CO reaction rates between 400 and 800 L of CO<sub>2sub> per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8–1.6 kg of CO<sub>2sub> per gram of catalytic metal per hour. We also present data showing CO<sub>2sub> conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 106 mol CO<sub>2sub> molcatalyst–1 during a multiday (36 hours total hours) CO<sub>2sub>electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 106 and 4 × 106 molCO<sub>2sub> molcatalyst–1 were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO<sub>2sub> conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO<sub>2sub> conversion technologies. Specifically, we show the following: (1) all electrochemical CO<sub>2sub> conversion systems will produce a net increase in CO<sub>2sub> emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient to power larger-scale, tonne per day CO<sub>2sub> conversion systems.

  11. Antiferromagnetic spin correlations and pseudogaplike behavior in Ca(Fe<sub>1-xsub>Cox)>2sub>As>2sub> studied by 75As nuclear magnetic resonance and anisotropic resistivity

    SciTech Connect (OSTI)

    Cui, J.; Roy, B.; Tanatar, M. A.; Ran, S.; Bud'ko, S. L.; Prozorov, R.; Canfield, P. C.; Furukawa, Y.

    2015-11-06

    We report 75As nuclear magnetic resonance (NMR) measurements of single-crystalline Ca(Fe<sub>1–xsub>Cox)>2sub>As>2sub> (x=0.023, 0.028, 0.033, and 0.059) annealed at 350°C for 7 days. From the observation of a characteristic shape of 75As NMR spectra in the stripe-type antiferromagnetic (AFM) state, as in the case of x=0 (T<sub>N>=170 K), clear evidence for the commensurate AFM phase transition with the concomitant structural phase transition is observed in x=0.023 (T<sub>N>=106 K) and x=0.028 (T<sub>N>=53 K). Through the temperature dependence of the Knight shifts and the nuclear spin lattice relaxation rates (1/T<sub>1sub>), although stripe-type AFM spin fluctuations are realized in the paramagnetic state as in the case of other iron pnictide superconductors, we found a gradual decrease of the AFM spin fluctuations below a crossover temperature T* that was nearly independent of Co-substitution concentration, and it is attributed to a pseudogaplike behavior in the spin excitation spectra of these systems. The T* feature finds correlation with features in the temperature-dependent interplane resistivity, <sub>ρc>(T), but not with the in-plane resistivity <sub>ρa>(T). The temperature evolution of anisotropic stripe-type AFM spin fluctuations is tracked in the paramagnetic and pseudogap phases by the 1/T<sub>1sub> data measured under magnetic fields parallel and perpendicular to the c axis. As a result, based on our NMR data, we have added a pseudogaplike phase to the magnetic and electronic phase diagram of Ca(Fe<sub>1–xsub>Cox)>2sub>As>2sub>.

  12. Perovskite-type La{sub 2}Ti{sub 2}O{sub 7} mesoporous photocatalyst

    SciTech Connect (OSTI)

    Onozuka, K.; Kawakami, Y.; Imai, H.; Yokoi, T.; Tatsumi, T.; Kondo, J.N.

    2012-08-15

    Crystalline particles of mesoporous La{sub 2}Ti{sub 2}O{sub 7}, a perovskite-type material, were prepared by hydrothermal synthesis at 210 Degree-Sign C in the presence of structure directing agent. Crystallization and simultaneous sintering occurred in the time course of the hydrothermal treatment, resulting in the improvement in crystallinity with a sacrifice of the decrease in surface area. The photocatalytic property was evaluated by hydrogen evolution from water with methanol sacrificial agent. The increase and the decrease of the material in crystallinity and surface area were responsible for the photocatalytic activity: the activity was improved by crystallization but the concurrent decrease in surface area (increase in size) of crystalline particles was disadvantageous. - Graphical abstract: A homogeneous mixture of La and Ti oxide with amorphous inorganic network was hydrothermally crystallized at low temperatures to a perovskite-type La{sub 2}Ti{sub 2}O{sub 7}. The small La{sub 2}Ti{sub 2}O{sub 7} particles with high crystallinity showed a potential as a photocatalyst for H{sub 2} evolution. Highlights: Black-Right-Pointing-Pointer Crystalline mesopourous La{sub 2}Ti{sub 2}O{sub 7} was prepared. Black-Right-Pointing-Pointer Hydrothermal treatment encouraged low temperature crystallization. Black-Right-Pointing-Pointer Small crystalline domain was advantageous to a photocatalytic reaction.

  13. Topologically identical, but geometrically isomeric layers in hydrous α-, β-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O and anhydrous Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})

    SciTech Connect (OSTI)

    Yu, Na; Klepov, Vladislav V.; Villa, Eric M.; Bosbach, Dirk; Suleimanov, Evgeny V.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.; Alekseev, Evgeny V.

    2014-07-01

    The hydrothermal reaction of uranyl nitrate with rubidium nitrate and arsenic (III) oxide results in the formation of polymorphic α- and β-Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O (α-, β-RbUAs) and the anhydrous phase Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] (RbUAs). These phases were structurally, chemically and spectroscopically characterized. The structures of all three compounds are based upon topologically identical, but geometrically isomeric layers. The layers are linked with each other by means of the Rb cations and hydrogen bonding. Dehydration experiments demonstrate that water deintercalation from hydrous α- and β-RbUAs yields anhydrous RbUAs via topotactic reactions. - Graphical abstract: Three different layer geometries observed in the structures of Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})] and α- and β- Rb[UO{sub 2}(AsO{sub 3}OH)(AsO{sub 2}(OH){sub 2})]·H{sub 2}O. Two different coordination environments of uranium polyhedra (types I and II) are shown schematically on the top of the figure. - Highlights: • Three new uranyl arsenates were synthesized from the hydrothermal reactions. • The phases consist of the topologically identical but geometrically different layers. • Topotactic transitions were observed in the processes of mono-hyrates dehydration.

  14. The fluorite-pyrochlore transformation of Ho{sub 2-y}Nd{sub y}Zr{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Clements, Richard; Hester, James R.; Kennedy, Brendan J.; Ling, Chris D.; Stampfl, Anton P.J.

    2011-08-15

    Twelve members of the Ho{sub 2-y}Nd{sub y}Zr{sub 2}O{sub 7} series, prepared using conventional solid state methods, have been characterised by neutron powder diffraction. Ho{sub 2}Zr{sub 2}O{sub 7} has a defect fluorite structure whereas Nd{sub 2}Zr{sub 2}O{sub 7} is found to adopt the ordered pyrochlore structure with the composition induced fluorite-pyrochlore transformation occurring near y=1. Rietveld analysis on the neutron data for all the compositions reveals an increase in lattice parameter as a function of y across the entire series, with a small discontinuity associated with the transformation. The neutron profile results suggest that domains of pyrochlore-type initially begin to form before crystallising into a separate phase, and therefore that anion and cation ordering processes are distinct. There is a strong correlation between the extent of disorder in the anion sublattice and the x-parameter of 48f oxygen. These results point the way to a better understanding of the stability observed in pyrochlore structures. - Graphical abstract: Neutron diffraction profiles for Nd{sub 2-y}Ho{sub y}Zr{sub 2}O{sub 7} type oxides reveal details of the transformation from the ordered pyrochlore structure (y=0) to the disordered fluorite structure (y=2). Highlights: > Structures of twelve members of the Ho{sub 2-y}Nd{sub y}Zr{sub 2}O{sub 7} series studied using neutron powder diffraction. > Domains of pyrochlore-type materials form at low doping levels. > Higher doping stabilises the pyrochlore. > Anion and cation ordering processes are distinct.

  15. Crystal structures and luminescence properties of novel compounds K{sub 4}M{sub 2}[Al{sub 2}Si{sub 8}O{sub 24}] (M = Ce, Gd)

    SciTech Connect (OSTI)

    Aksenov, S. M., E-mail: aks.crys@gmail.com [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Rassulov, V. A. [Russian Academy of Sciences, Fedorovsky All-Russian Research Institute of Mineral Resources (Russian Federation)] [Russian Academy of Sciences, Fedorovsky All-Russian Research Institute of Mineral Resources (Russian Federation); Rastsvetaeva, R. K. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Taroev, V. K. [Russian Academy of Sciences, Institute of Geochemistry, Siberian Branch (Russian Federation)] [Russian Academy of Sciences, Institute of Geochemistry, Siberian Branch (Russian Federation)

    2013-11-15

    Two novel potassium rare earth silicates, obtained by hydrothermal synthesis, have been investigated by X-ray diffraction and described by the general formula K{sub 4}M{sub 2}[Al{sub 2}Si{sub 8}O{sub 24}] (M = Ce, Gd). The parameters of the monoclinic K{sub 4}Ce{sub 2}[Al{sub 2}Si{sub 8}O{sub 24}] and K{sub 4}Gd{sub 2}[Al{sub 2}Si{sub 8}O{sub 24}] cells are, respectively, as follows: a = 26.867(1), 26.6520(2) A; b = 7.4150(2), 7.2854(1) A; c = 14.910(1), 14.8182(1) A; {beta} = 123.52(1) Degree-Sign , 123.46(1) Degree-Sign ; and sp. gr. P2{sub 1}/n. The structures are solved by the charge flipping method and refined in the anisotropic approximation of thermal vibrations for atoms to R = 5.2 and 2.5%, respectively. The compounds under study are crystallized into a new structural type, which is based on two-level [Al{sub 2}Si{sub 8}O{sub 24}] layers, combined into a three-dimensional framework by columns of edge-sharing seven-vertex REE polyhedra. Potassium atoms are located in the framework channels. The spectral luminescence characteristics are determined. The luminescence bands are typical of Gd{sup 3+} and Ce{sup 3+} ions. Upon excitation by light with {lambda}{sub exc} = 246 nm, a band due to the {sup 2}D {yields} {sup 8}F{sub 5/2} transition with {lambda}{sub max} = 430 nm is observed in the spectrum of K{sub 4}Ce{sub 2}[Al{sub 2}Si{sub 8}O{sub 24}] and a band related to the {sup 6}P{sub 7/2} {yields} {sup 8}S{sub 7/2} transition with {lambda}{sub max} = 311 nm is observed in the spectrum of K{sub 4}Gd{sub 2}[Al{sub 2}Si{sub 8}O{sub 24}].

  16. Accelerator driven sub-critical core

    DOE Patents [OSTI]

    McIntyre, Peter M; Sattarov, Akhdiyor

    2015-03-17

    Systems and methods for operating an accelerator driven sub-critical core. In one embodiment, a fission power generator includes a sub-critical core and a plurality of proton beam generators. Each of the proton beam generators is configured to concurrently provide a proton beam into a different area of the sub-critical core. Each proton beam scatters neutrons within the sub-critical core. The plurality of proton beam generators provides aggregate power to the sub-critical core, via the proton beams, to scatter neutrons sufficient to initiate fission in the sub-critical core.

  17. CONTINUOUS PROCESS FOR THE CONVERSION OF UF$sub 6$ TO UF$sub 4$

    DOE Patents [OSTI]

    Smiley, S.H.; Brater, D.C.; Nimmo, R.H.

    1959-10-01

    A method is presented for reducing UF/sub 6/ to UF/sub 6/ with hydrogen. A preheated mixture of UF/sub 6/ and fluorine is contacted with a stoichiometric excess of preheated hydrogen in a reaction chamber thereby producing UF/sub 6/. The UF/sub 6/ reacts quantitatively and the UF/sub 6/ produced is of high purity and high density.

  18. Dynamic study of (De)sodiation in alpha-MnO<sub>2sub> nanowires

    SciTech Connect (OSTI)

    Yuan, Yifei; Ma, Lu; He, Kun; Yao, Wentao; Nie, Anmin; Bi, Xuanxuan; Amine, Khalil; Wu, Tianpin; Lu, Jun; Shahbazian-Yassr, Reza

    2016-01-01

    In this report, the electrochemical sodiation and desodiation in single crystalline alpha-MnO<sub>2sub> nanowires are studied dynamically at both single particle level using in situ transmission electron microscopy (TEM) and bulk level using in situ synchrotron X-ray. The TEM results suggest that the first sodiation process starts with tunnel-based Na+ intercalation, experiences the formation of Na<sub>0.5sub>MnO>2sub> as a result of tunnel degradation, and ends with the Mn<sub>2sub>O>3sub> phase. The inserted Na+ can be partially extracted out of the sodiated products, and the following cycles are dominated by the reversible conversion reaction between Na<sub>0.sub>5MnO<sub>2sub> and Mn<sub>2sub>O>3sub>. The Mn valence evolution inside a cycling coin using alpha-MnO<sub>2sub> nanowire electrode also exhibits partially reversible characteristic, agreeing well with the in situ TEM analysis. The sodiation is compared with lithiation in the same alpha-MnO<sub>2sub> nanowires. Both Na+ and Li+ interact with the tunneled structure via a similar tunnel -driven intercalation mechanism before Mn4+ is reduced to Mn3.5+. For the following deep insertion, the tunnels survive up. to LiMnO<sub>2sub> (Mn3+) during lithiation, while the sodiation proceeds via a different mechanism that involves obvious phase transition and fast tunnel degradation after Mn's valence is below 3.5+. The difference in charge carrier insertion mechanisms can be ascribed to the strong interaction between the tunnel frame and inserted Na+ possessing a larger ionic size than inserted Li+.

  19. Tau neutrinos underground: Signals of {nu}{sub {mu}}{yields}{nu}{sub {tau}}

    Office of Scientific and Technical Information (OSTI)

    oscillations with extragalactic neutrinos (Journal Article) | SciTech Connect Tau neutrinos underground: Signals of {nu}{sub {mu}}{yields}{nu}{sub {tau}} oscillations with extragalactic neutrinos Citation Details In-Document Search Title: Tau neutrinos underground: Signals of {nu}{sub {mu}}{yields}{nu}{sub {tau}} oscillations with extragalactic neutrinos The appearance of high energy tau neutrinos due to {nu}{sub {mu}}{yields}{nu}{sub {tau}} oscillations of extragalactic neutrinos can be

  20. Dispersion states and acid properties of SiO{sub 2}-supported Nb{sub 2}O{sub 5}

    SciTech Connect (OSTI)

    He, Jie; Li, Qing-Jie; Fan, Yi-Ning

    2013-06-15

    Nb{sub 2}O{sub 5}/SiO{sub 2} samples were prepared by the incipient-wetness impregnation method using niobium oxalate aqueous solution. The microstructure and dispersion process of the niobia species supported on SiO{sub 2} were characterized by means of power X-ray diffraction (XRD), laser Raman spectroscopy (LRS), and UVvis diffuse reflectance spectroscopy (UVvis DRS). The acid properties were investigated by the method of Hammett indicator and Pyridine adsorption infrared (Py-IR) spectroscopy. The results showed that the dispersion process of Nb{sub 2}O{sub 5} was performed by consuming surface hydroxyl groups of the amorphous SiO{sub 2} support. The aggregation of niobia species led to the formation of microcrystalline particles, so that there was no a clear monolayer dispersion capacity for Nb{sub 2}O{sub 5} supported on amorphous SiO{sub 2}. Furthermore, the catalytic activities of the as-prepared samples were evaluated by the condensation reaction of iso-butene (IB) and iso-butyraldehyde (IBA) to form 2,5-dimethyl-2,4-hexadiene (DMHD). The catalytic activities of the as-prepared samples for the condensation and their acid properties were strongly affected by the dispersion states. - Graphical abstract: The acid amount and strength of Nb{sub 2}O{sub 5}/SiO{sub 2} samples varied with the increase of Nb{sub 2}O{sub 5} loading. The catalytic activities of the as-prepared samples for the condensation and their acid properties were strongly affected by the dispersion states. - Highlights: The dispersed process of Nb{sub 2}O{sub 5} was completed by consuming surface hydroxyl groups of SiO{sub 2}. XRD quantitative phase analysis is not applicable for oxides dispersing on amorphous support. The catalytic activity of Nb{sub 2}O{sub 5}/SiO{sub 2} is closely related to the dispersion state of SiO{sub 2}.

  1. Ti-substituted tunnel-type Na<sub>0.44sub>MnO>2sub> oxide as a negative electrode for aqueous sodium-ion batteries

    SciTech Connect (OSTI)

    Wang, Yuesheng; Liu, Jue; Lee, Byungju; Qiao, Ruimin; Yang, Zhenzhong; Xu, Shuyin; Yu, Xiqian; Gu, Lin; Hu, Yong-Sheng; Yang, Wanli; Kang, Kisuk; Li, Hong; Yang, Xiao-Qing; Chen, Liquan; Huang, Xuejie

    2015-03-25

    The aqueous sodium-ion battery system is a safe and low-cost solution for large-scale energy storage, due to the abundance of sodium and inexpensive aqueous electrolytes. Although several positive electrode materials, e.g., Na<sub>0.44sub>MnO>2sub>, were proposed, few negative electrode materials, e.g., activated carbon and NaTi<sub>2sub>(PO>4sub>)>3sub>, are available. Here we show that Ti-substituted Na<sub>0.44sub>MnO>2sub> (Na<sub>0.44sub>[Mn>1-xsub>Tix]O>2sub>) with tunnel structure can be used as a negative electrode material for aqueous sodium-ion batteries. This material exhibits superior cyclability even without the special treatment of oxygen removal from the aqueous solution. Atomic-scale characterizations based on spherical aberration-corrected electron microscopy and ab initio calculations are utilized to accurately identify the Ti substitution sites and sodium storage mechanism. Ti substitution tunes the charge ordering property and reaction pathway, significantly smoothing the discharge/charge profiles and lowering the storage voltage. Both the fundamental understanding and practical demonstrations suggest that Na<sub>0.44sub>[Mn>1-xsub>Tix]O>2sub> is a promising negative electrode material for aqueous sodium-ion batteries.

  2. Preparation of MgH{sub 2} composite with a composition of 40%MgH{sub 2} + 30%LiBH{sub 4} + 30%(2LiBH{sub 4} + MgF{sub 2})

    SciTech Connect (OSTI)

    Hong, Seong-Hyeon; Song, Myoung Youp

    2012-09-15

    Graphical abstract: Hydrogen content vs. desorption time curves for consecutive 1st desorptions of 40 wt%MgH{sub 2} + 30 wt%LiBH{sub 4} + 30 wt%(2LiBH{sub 4} + MgF{sub 2}) at 533–873 K. Highlights: ► Addition of MgF{sub 2} and LiBH{sub 4} with a higher hydrogen storage capacity to MgH{sub 2}. ► Preparation of 40%MgH{sub 2} + 30%LiBH{sub 4} + 30% (2LiBH{sub 4} + MgF{sub 2}) composite. ► Examination of desorption properties of the composite. ► Total desorbed hydrogen quantity for consecutive 1st desorptions of 7.07 wt%. ► Reactions of LiBH{sub 4} → LiH + B + (3/2)H{sub 2}, and 2LiBH{sub 4} + MgF{sub 2} → 2LiF + MgB{sub 2} + 4H{sub 2}. -- Abstract: A mixture of containing two chemical equivalents of lithium borohyride and one equivalent of magnesium fluoride is known to yield hydrogen in an amount of about 7.6 wt% of the mixture when heated to about 150 °C at atmospheric pressure by the following reaction; 2LiBH{sub 4} + MgF{sub 2} = 2LiF + MgB{sub 2} + 4H{sub 2}. In order to increase hydrogen storage capacity of Mg-based materials, a mixture with a composition of 2LiBH{sub 4} + MgF{sub 2} and LiBH{sub 4}with a higher hydrogen storage capacity of 18.4 wt% were added to MgH{sub 2}. MgH{sub 2} composite with a composition of 40 wt%MgH{sub 2} + 30 wt%LiBH{sub 4} + 30 wt%(2LiBH{sub 4} + MgF{sub 2}) was prepared by reactive mechanical grinding. The hydrogen storage properties of the sample were then examined. Hydrogen content vs. desorption time curves for consecutive 1st desorptions of 40 wt%MgH{sub 2} + 30 wt%LiBH{sub 4} + 30 wt%(2LiBH{sub 4} + MgF{sub 2}) at 533–873 K showed that the total desorbed hydrogen quantity for consecutive 1st desorptions is 7.07 wt%.

  3. 2D-network of inorganic-organic hybrid material built on Keggin type polyoxometallate and amino acid: [L-C{sub 2}H{sub 6}NO{sub 2}]{sub 3}[(PO{sub 4})Mo{sub 12}O{sub 36}].5H{sub 2}O

    SciTech Connect (OSTI)

    Alizadeh, M.H. Mirzaei, M.; Razavi, H.

    2008-03-04

    A new inorganic-organic hybrid material based on polyoxometallate, [L-C{sub 2}H{sub 6}NO{sub 2}]{sub 3}[(PO{sub 4})Mo{sub 12}O{sub 36}].5H{sub 2}O, has been successfully synthesized and characterized by single-crystal X-ray analysis, elemental analysis, infrared and ultraviolet spectroscopy, proton nuclear magnetic resonance and differential thermal analysis techniques. The title compound crystallizes in the monoclinic space group, P2{sub 1}/c{sub ,} with a = 12.4938 (8) A, b = 19.9326 (12) A, c = 17.9270 (11) A, {beta} = 102.129 (1){sup o}, V = 4364.8 (5) A{sup 3}, Z = 4 and R{sub 1}(wR{sub 2}) = 0.0513, 0.0877. The most remarkable structural feature of this hybrid can be described as two-dimensional inorganic infinite plane-like (2D/{infinity} [(PO{sub 4})Mo{sub 12}O{sub 36}]{sup 3-}) which forming via weak Van der Waals interactions along the z axis. The characteristic band of the Keggin anion [(PO{sub 4})Mo{sub 12}O{sub 36}]{sup 3-} appears at 210 nm in the UV spectrum. Thermal analysis indicates that the Keggin anion skeleton begins to decompose at 520 deg. C.

  4. A dispersive treatment of K<sub>l4sub> decays

    SciTech Connect (OSTI)

    Colangelo, Gilberto; Passemar, Emilie; Stoffer, Peter

    2015-04-28

    K<sub>l4sub> decays offer several reasons of interest: they allow an accurate measurement of ??-scattering lengths; they provide the best source for the determination of some low-energy constants of <sub>x>PT; one form factor is directly related to the chiral anomaly, which can be measured here. We present a dispersive treatment of K<sub>l4sub> decays that provides a resummation of ??- and K<sub>?>-rescattering effects. In addition, the free parameters of the dispersion relation are fitted to the data of the high-statistics experiments E865 and NA48/2. The matching to<sub>x>PT at NLO and NNLO enables us to determine the LECs Lr<sub>1sub>, Lr<sub>2sub> and Lr<sub>3sub>. With recently published data from NA48/2, the LEC Lr<sub>9sub> can be determined as well. In contrast to a pure chiral treatment, the dispersion relation describes the observed curvature of one of the form factors, which we understand as a rescattering effect beyond NNLO.

  5. Synthesis and X-ray diffraction study of Cu{sub 2}ZnSn(S{sub x}Se{sub 1-x}){sub 4} solid solutions

    SciTech Connect (OSTI)

    Sheleg, A. U. Hurtavy, V. G.; Chumak, V. A.

    2015-09-15

    Quaternary compounds Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSnSe{sub 4} and solid solutions on their basis have been fabricated by one-temperature synthesis from elementary components: Cu, Zn, Sn, S, and Se. Single crystals of these compounds have been grown by the method of chemical gas-transport reactions from polycrystalline samples. The compositional dependence of the unit-cell parameters of Cu{sub 2}ZnSn(S{sub x}Se{sub 1–x}){sub 4} has been investigated by X-ray diffraction. It is found that parameters a and c linearly decrease with an increase in sulfur concentration in accordance with Vegard’s law. The temperature dependences of parameters a and thermalexpansion coefficients α{sub a} of Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSnSe{sub 4} single crystals in the range of 100–300 K are determined.

  6. First-principles studies on molecular beam epitaxy growth of GaAs<sub>1-xsub>Bix>

    SciTech Connect (OSTI)

    Luo, Guangfu; Yang, Shujiang; Li, Jincheng; Arjmand, Mehrdad; Szlufarska, Izabela; Brown, April S.; Kuech, Thomas F.; Morgan, Dane

    2015-07-14

    We investigate the molecular beam epitaxy (MBE) growth of GaAs<sub>1-xsub>Bix> film using density functional theory with spin-orbit coupling to understand the growth of this film, especially the mechanisms of Bi incorporation. We study the stable adsorption structures and kinetics of the incident molecules (As? molecule, Ga atom, Bi atom, and Bi? molecule) on the (2 x 1)-Ga<sub>sub>||Bi surface and a proposed q(1 x 1)-Ga<sub>sub>||AsAs surface has a quasi-(1 x 1) As layer above the Ga-terminated GaAs substrate and a randomly oriented As dimer layer on top. We obtain the desorption and diffusion barriers of the adsorbed molecules and also the reaction barriers of three key processes related to Bi evolution, namely, Bi incorporation, As/Bi exchange, and Bi clustering. The results help explain the experimentally observed dependence of Bi incorporation on the As/Ga ratio and growth temperature. Furthermore, we find that As? exchange with Bi of the (2 x 1)-Ga<sub>sub>||Bi surface is a key step controlling the kinetics of the Bi incorporation. Finally, we explore two possible methods to enhance the Bi incorporation, namely, replacing the MBE growth mode from codeposition of all fluxes with a sequential deposition of fluxes and applying asymmetric in-plane strain to the substrate.

  7. Structural and magnetic properties of triethylene glycol stabilized Zn{sub x}Co{sub 1?x}Fe{sub 2}O{sub 4} nanoparticles

    SciTech Connect (OSTI)

    Sozeri, H.; Durmus, Z.; Baykal, A.

    2012-09-15

    Highlights: ? Monodispersed TREG stabilized Zn{sub x}Co{sub 1?x}Fe{sub 2}O{sub 4} NP's were prepared via hydrothermal method. ? Zn{sub x0.6}Co{sub 0.4}Fe{sub 2}O{sub 4} NP's has superparamagnetic behavior like absence of saturation at high fields. ? The lattice parameter (a{sub o}) increases linearly with the addition of Zn and follows Vegard's law. -- Abstract: Zn substituted cobalt ferrite nanoparticles having formula of Zn{sub x}Co{sub 1?x}Fe{sub 2}O{sub 4} (x = 0.01.0) were prepared by hydrothermal technique. In this process, triethylene glycol was used as a solvent and surfactant, anhydrous sodium hydroxide was used as an alkalinity additive. Investigation of the structural, morphological and thermal properties were carried out using X-ray diffraction (XRD), infrared spectroscopy (FT-IR), transmission electron spectroscopy (TEM) and thermal analysis (TGA) respectively. The X-ray diffraction study reveals that the lattice constant of cobalt ferrite increases with the increase of Zn content. Magnetization measurements showed that as zinc concentration increases saturation magnetization initially stays constant and then decreases monotically. Samples having high zinc concentration (x ? 0.6) have superparamagnetic behavior like absence of saturation at high fields, low saturation magnetization values and immeasurable coercivity. These features were explained by surface spin disorder and canted spins.

  8. Strain induced Z{sub 2} topological insulating state of ?-As{sub 2}Te{sub 3}

    SciTech Connect (OSTI)

    Pal, Koushik; Waghmare, Umesh V.

    2014-08-11

    Topological insulators are non-trivial quantum states of matter which exhibit a gap in the electronic structure of their bulk form, but a gapless metallic electronic spectrum at the surface. Here, we predict a uniaxial strain induced electronic topological transition (ETT) from a band to topological insulating state in the rhombohedral phase (space group: R3{sup }m) of As{sub 2}Te{sub 3} (?-As{sub 2}Te{sub 3}) through first-principles calculations including spin-orbit coupling within density functional theory. The ETT in ?-As{sub 2}Te{sub 3} is shown to occur at the uniaxial strain ?{sub zz}?=??0.05 (?{sub zz}?=?1.77?GPa), passing through a Weyl metallic state with a single Dirac cone in its electronic structure at the ? point. We demonstrate the ETT through band inversion and reversal of parity of the top of the valence and bottom of the conduction bands leading to change in the ?{sub 2} topological invariant ?{sub 0} from 0 to 1 across the transition. Based on its electronic structure and phonon dispersion, we propose ultra-thin films of As{sub 2}Te{sub 3} to be promising for use in ultra-thin stress sensors, charge pumps, and thermoelectrics.

  9. Synthesis and crystal structure of bis(3-ammoniumphenyl) sulfone dinitrate [C{sub 12}H{sub 14}N{sub 2}O{sub 2}S](NO{sub 3}){sub 2}

    SciTech Connect (OSTI)

    Mahroug, A.; Belhouchet, M. Mhiri, T.

    2013-07-15

    A new organic nitrate with the formula [C{sub 12}H{sub 14}N{sub 2}O{sub 2}S](NO{sub 3}){sub 2}, has been prepared and analyzed by X-ray diffraction. This compound crystallizes in the orthorhombic system: a = 16.771 (3), b = 13.884(2), c = 13.884(2) A, V = 3232.7(7)A{sup 3}, Z = 8, space group Pna2{sub 1}. Crystal structure can be described as a succession of organic and inorganic layers parallel to b, c plane. H-bonds between the different species play an important role in the three-dimensional network cohesion.

  10. Electrical properties of In{sub 2}Se{sub 3} single crystals and photosensitivity of Al/In{sub 2}Se{sub 3} Schottky barriers

    SciTech Connect (OSTI)

    Bodnar, I. V.; Ilchuk, G. A.; Petrus', R. Yu.; Rud', V. Yu.; Rud', Yu. V.; Serginov, M.

    2009-09-15

    In{sub 2}Se{sub 3} single crystals {approx}40 mm long and 14 mm in diameter were grown by the Bridgman method. The composition of grown single crystals and their crystal structure were determined. The conductivity ({sigma}) and Hall constant (R) of grown single crystals were measured and the first Schottky barriers Al/n-In{sub 2}Se{sub 3} were fabricated. Rectification and photovoltaic effect were detected in the new structures. Based on the study of the photosensitivity spectra of Al/n-In{sub 2}Se{sub 3} structures, the nature of the interband transitions and band gap of In{sub 2}Se{sub 3} crystals were determined. It was concluded that the new structures can be applied to develop broadband photoconverters of optical radiation.

  11. Solution-processable glass LiI-Li<sub>4sub>SnS>4sub> superionic conductors for all-solid-state Li-ion batteries

    SciTech Connect (OSTI)

    Kern Ho Park; Oh, Dae Yang; Choi, Young Eun; Nam, Young Jin; Han, Lili; Kim, Ju -Young; Xin, Huolin; Lin, Feng; Oh, Seung M.; Jung, Yoon Seok

    2015-12-22

    The new, highly conductive (4.1 × 10–4 S cm–1 at 30 °C), highly deformable, and dry-air-stable glass 0.4LiI-0.6Li<sub>4sub>SnS>4sub> is prepared using a homogeneous methanol solution. Furthermore, the solution process enables the wetting of any exposed surface of the active materials with highly conductive solidified electrolytes (0.4LiI-0.6Li<sub>4sub>SnS>4sub>), resulting in considerable improvements in electrochemical performances of these electrodes over conventional mixture electrodes.

  12. Novel CO<sub>2sub> Foam Concepts and Injection Schemes for Improving CO<sub>2sub> Sweep Efficiency in Sandstone and Carbonate Hydrocarbon Formations

    SciTech Connect (OSTI)

    Nguyen, Quoc; Hirasaki, George; Johnston, Keith

    2015-02-05

    We explored cationic, nonionic and zwitterionic surfactants to identify candidates that have the potential to satisfy all the key requirements for CO<sub>2sub> foams in EOR. We have examined the formation, texture, rheology and stability of CO<sub>2sub> foams as a function of the surfactant structure and formulation variables including temperature, pressure, water/CO<sub>2 sub>ratio, surfactant concentration, salinity and concentration of oil. Furthermore, the partitioning of surfactants between oil and water as well as CO<sub>2sub> and water was examined in conjunction with adsorption measurements on limestone by the Hirasaki lab to develop strategies to optimize the transport of surfactants in reservoirs.

  13. Crystal structure of a new amine nitrate: 4-dimethylaminopyridinium nitrate (C{sub 7}H{sub 11}N{sub 2})NO{sub 3}

    SciTech Connect (OSTI)

    Benhassan, D. Rekik, W.; Naïli, H.; Ślepokura, Katarzyna

    2015-12-15

    The title compound (C{sub 7}H{sub 11}N{sub 2})NO{sub 3} (I) was obtained by the slow evaporation method at room temperature. Its crystal structure consists of organic cations (C{sub 7}H{sub 11}N{sub 2}){sup +} and nitrate anions (NO{sub 3}){sup –} linked by two types of hydrogen bonds. Each monoprotonated nitrogen atom, called bifurcated, is engaged in two N–H···O hydrogen bonds with two symmetric oxygen atoms. In addition, the crystal structure stability is established by C–H···O hydrogen bonds that ensure the formation of infinite layers, parallel to (001) plane. These layers are related together through π···π interactions established between aromatic amines.

  14. Giant increase in critical current density of K<sub>xFe>2-ysub>Se? single crystals

    SciTech Connect (OSTI)

    Lei, Hechang; Petrovic, C.

    2011-12-28

    The critical current density Jabc of K<sub>xFe>2-ysub>Se? single crystals can be enhanced by more than one order of magnitude, up to ~2.110? A/cm by the post annealing and quenching technique. A scaling analysis reveals the universal behavior of the normalized pinning force as a function of the reduced field for all temperatures, indicating the presence of a single vortex pinning mechanism. The main pinning sources are three-dimensional (3D) point-like normal cores. The dominant vortex interaction with pinning centers is via spatial variations in critical temperature T<sub>c> (?T<sub>c> pinning).

  15. Solar reduction of CO.sub.2

    DOE Patents [OSTI]

    Jensen, Reed J.; Lyman, John L.; King, Joe D.; Guettler, Robert D.

    2000-01-01

    The red shift of the absorption spectrum of CO.sub.2 with increasing temperature permits the use of sunlight to photolyze CO.sub.2 to CO. The process of the present invention includes: preheating CO.sub.2 to near 1800 K; exposing the preheated CO.sub.2 to sunlight, whereby CO, O.sub.2 and O are produced; and cooling the hot product mix by rapid admixture with room temperature CO.sub.2. The excess thermal energy may be used to produce electricity and to heat additional CO.sub.2 for subsequent process steps. The product CO may be used to generate H.sub.2 by the shift reaction or to synthesize methanol.

  16. Reactions of methyl groups on a non-reducible metal oxide: The reaction of iodomethane on stoichiometric ?-Cr<sub>2sub>O>3sub>(0001)

    SciTech Connect (OSTI)

    Dong, Yujung; Brooks, John D.; Chen, Tsung-Liang; Mullins, David R.; Cox, David F.

    2015-06-10

    The reaction of iodomethane on the nearly stoichiometric ?-Cr<sub>2sub>O>3(sub>0001) surface produces gas phase ethylene, methane, and surface iodine adatoms. The reaction is first initiated by the dissociation of iodomethane into surface methyl fragments, -CH<sub>3sub>, and iodine adatoms. Methyl fragments bound at surface Cr cation sites undergo a rate-limiting dehydrogenation reaction to methylene, =CH<sub>2sub>. The methylene intermediates formed from methyl dehydrogenation can then undergo coupling reactions to produce ethylene via two principle reaction pathways: (1) direct coupling of methylene and (2) methylene insertion into the methyl surface bond to form surface ethyl groups which undergo ?-H elimination to produce ethylene. The liberated hydrogen also combines with methyl groups to form methane. Iodine adatoms from the dissociation of iodomethane deactivate the surface by simple site blocking of the surface Cr3+ cations.

  17. Electron backscatter diffraction analysis of gold nanoparticles on Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7??}

    SciTech Connect (OSTI)

    Bochmann, A.; Teichert, S.; Katzer, C.; Schmidl, F.

    2015-06-07

    It has been shown recently that the incorporation of gold nanoparticles into Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7??} enhances the superconducting properties of this material in a significant way. Previous XRD and TEM investigations suggest different crystallographic relations of the gold nanoparticles with respect to the epitaxial Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7??}. Here, detailed investigations of the crystal orientations for a large ensemble of gold nanoparticles with electron backscatter diffraction are reported. The average size of the gold nanoparticles is in the range of 60?nm80?nm. We identified five different types of heteroepitaxial relationships between the gold nanoparticles and the superconductor film, resulting in complex pole figures. The observed different types of crystallographic orientations are discussed based on good lattice matching and the formation of low energy interfaces.

  18. Molecular beam epitaxy growth of SnO{sub 2} using a tin chemical precursor

    SciTech Connect (OSTI)

    Wang, Tianqi; Prakash, Abhinav; Jalan, Bharat; Warner, Ellis; Gladfelter, Wayne L.

    2015-03-15

    The authors report on the development of a molecular beam epitaxy approach for atomic layer controlled growth of phase-pure, single-crystalline epitaxial SnO{sub 2} films with scalable growth rates using a highly volatile precursor (tetraethyltin) for tin and rf-oxygen plasma for oxygen. Smooth, epitaxial SnO{sub 2} (101) films on r-sapphire (101{sup ¯}2) substrates were grown as a function of tin precursor flux and substrate temperatures between 300 and 900 °C. Three distinct growth regimes were identified where SnO{sub 2} films grew in a reaction-, flux-, and desorption-limited mode, respectively, with increasing substrate temperature. In particular, with increasing tin flux, the growth rates were found to increase and then saturate indicating any excess tin precursor desorbs above a critical beam equivalent pressure of tin precursor. Important implications of growth kinetic behaviors on the self-regulating stoichiometric growth of perovskite stannates are discussed.

  19. Improvement in oil recovery using cosolvents with CO{sub 2} gas floods

    SciTech Connect (OSTI)

    Raible, C.

    1992-01-01

    This report presents the results of investigations to improve oil recovery using cosolvents in CO{sub 2} gas floods. Laboratory experiments were conducted to evaluate the application and selection of cosolvents as additives to gas displacement processes. A cosolvent used as a miscible additive changed the properties of the supercritical gas phase. Addition of a cosolvent resulted in increased viscosity and density of the gas mixture, and enhanced extraction of oil compounds into the CO{sub 2} rich phase. Gas phase properties were measured in an equilibrium cell with a capillary viscometer and a high pressure densitometer. A number of requirements must be considered in the application of a cosolvent. Cosolvent miscibility with CO{sub 2}, brine solubility, cosolvent volatility and relative quantity of the cosolvent partitioning into the oil phase were factors that must be considered for the successful application of cosolvents. Coreflood experiments were conducted with selected cosolvents to measure oil recovery efficiency. The results indicate lower molecular weight additives, such as propane, are the most effective cosolvents to increase oil recovery.

  20. Improvement in oil recovery using cosolvents with CO sub 2 gas floods

    SciTech Connect (OSTI)

    Raible, C.

    1992-01-01

    This report presents the results of investigations to improve oil recovery using cosolvents in CO{sub 2} gas floods. Laboratory experiments were conducted to evaluate the application and selection of cosolvents as additives to gas displacement processes. A cosolvent used as a miscible additive changed the properties of the supercritical gas phase. Addition of a cosolvent resulted in increased viscosity and density of the gas mixture, and enhanced extraction of oil compounds into the CO{sub 2} rich phase. Gas phase properties were measured in an equilibrium cell with a capillary viscometer and a high pressure densitometer. A number of requirements must be considered in the application of a cosolvent. Cosolvent miscibility with CO{sub 2}, brine solubility, cosolvent volatility and relative quantity of the cosolvent partitioning into the oil phase were factors that must be considered for the successful application of cosolvents. Coreflood experiments were conducted with selected cosolvents to measure oil recovery efficiency. The results indicate lower molecular weight additives, such as propane, are the most effective cosolvents to increase oil recovery.

  1. Preparation and characterization of magnetic CsH{sub 2}PW{sub 12}O{sub 40}/FeSiO{sub 2} nanocatalysts for biodiesel production

    SciTech Connect (OSTI)

    Feyzi, Mostafa; Nourozi, Leila; Zakarianezhad, Mohammad

    2014-12-15

    Graphical abstract: In this study, a series of magnetic CsH{sub 2}PW{sub 12}O{sub 40}/FeSiO{sub 2} nanocatalysts were prepared and tested for biodiesel production. The best operational conditions were CH3OH/oil = 12/1 at 60 C with mechanical stirring, the biodiesel yield reaches to 81% in 4 h. Also notably, recovery of the catalyst can be achieved easily with the help of an external magnet with no need for expensive ultracentrifugation. - Highlights: Effects of preparation conditions for biodiesel production were studied. The CsH{sub 2}PW{sub 12}O{sub 40}/FeSiO{sub 2} catalyst is efficient catalyst for biodiesel production. The reaction conditions were found methanol/oil = 12/1, T = 60 C. - Abstract: The magnetic CsH{sub 2}PW{sub 12}O{sub 40}/FeSiO{sub 2} nanocatalysts were prepared via combination of solgel and impregnation methods. The effects of different H{sub 3}PW{sub 12}O{sub 40}/(FeSiO{sub 2}) weight percentage, loading of Cs as a promotor and calcination conditions on the catalytic performance has been studied. It was found that the catalyst with H{sub 3}PW{sub 12}O{sub 40}/FeSiO{sub 2} = 4 wt.% and Cs = 2 wt.% is an optimal catalyst for biodiesel production. The activity of optimal catalyst was studied in different operational conditions. The best operational conditions were CH{sub 3}OH/oil = 12/1 at 60 C with mechanical stirring rate of 500 rpm and the biodiesel yield reaches to 81% in 4 h. Characterization of catalysts was carried out by using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), N{sub 2} adsorptiondesorption measurements methods, Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC)

  2. Large piezoelectricity in Pb-free 0.96(K{sub 0.5}Na{sub 0.5}){sub 0.95}Li{sub 0.05}Nb{sub 0.93}Sb{sub 0.07}O{sub 3}−0.04BaZrO{sub 3} ceramic: A perspective from microstructure

    SciTech Connect (OSTI)

    Gao, Jinghui Li, Huiying; Zhong, Lisheng; Li, Shengtao; Hao, Yanshuang; Ren, Shuai Fang, Minxia; Ren, Xiaobing; Kimoto, Takayoshi; Wang, Yu

    2015-02-28

    We employ transmission electron microscopy to explore the reason for large piezoelectricity (d{sub 33}≈400pC/N) in a Pb-free 0.96(K{sub 0.5}Na{sub 0.5}){sub 0.95}Li{sub 0.05}Nb{sub 0.93}Sb{sub 0.07}O{sub 3} −0.04BaZrO{sub 3} ceramic from microstructure. The result shows that the high piezoelectricity corresponds to a miniaturized nanodomain configuration in a domain hierarchy. The nanodomains disappear on heating accompanied by a reduction in d{sub 33} value. Further convergent beam electron diffraction study reveals a coexistence of tetragonal and orthorhombic phase, which indicates that large piezoelectricity of KNLNS{sub 0.07}-BZ may stem from easy polarization rotation due to low polarization anisotropy on the tetragonal-orthorhombic phase boundary.

  3. Structural and chemical ordering of Heusler Co<sub>xsub>MnyGez> epitaxial films on Ge (111). Quantitative study using traditional and anomalous x-ray diffraction techniques

    SciTech Connect (OSTI)

    Collins, B. A.; Chu, Y.; He, L.; Haskel, D.; Tsui, F.

    2015-12-14

    We found that epitaxial films of Co<sub>xsub>MnyGez> grown on Ge (111) substrates by molecular-beam-epitaxy techniques have been investigated as a continuous function of composition using combinatorial synchrotron x-ray diffraction (XRD) and x-ray fluorescence (XRF) spectroscopy techniques. A high-resolution ternary epitaxial phase diagram is obtained, revealing a small number of structural phases stabilized over large compositional regions. Ordering of the constituent elements in the compositional region near the full Heusler alloy Co<sub>2sub>MnGe has been examined in detail using both traditional XRD and a new multiple-edge anomalous diffraction (MEAD) technique. Multiple-edge anomalous diffraction involves analyzing the energy dependence of multiple reflections across each constituent absorption edge in order to detect and quantify the elemental distribution of occupation in specific lattice sites. Results of this paper show that structural and chemical ordering are very sensitive to the Co : Mn atomic ratio, such that the ordering is the highest at an atomic ratio of 2 but significantly reduced even a few percent off this ratio. The in-plane lattice is nearly coherent with that of the Ge substrate, while the approximately 2% lattice mismatch is accommodated by the out-of-plane tetragonal strain. Furthermore, the quantitative MEAD analysis reveals no detectable amount (<0.5%) of Co-Mn site swapping, but instead high levels (26%) of Mn-Ge site swapping. Increasing Ge concentration above the Heusler stoichiometry (Co <sub>0.5sub> Mn <sub>0.25 sub>Ge <sub>0.25 sub>) is shown to correlate with increased lattice vacancies, antisites, and stacking faults, but reduced lattice relaxation. The highest degree of chemical ordering is observed off the Heusler stoichiometry with a Ge enrichment of 5 at.%.

  4. Mechanically-induced disorder in CaFe<sub>2sub>As>2sub>: A 57Fe Mssbauer study

    SciTech Connect (OSTI)

    Ma, Xiaoming; Ran, Sheng; Canfield, Paul C.; Bud'ko, Sergey L.

    2015-10-17

    57Fe Mssbauer spectroscopy was used to perform a microscopic study on the extremely pressure and strain sensitive compound, CaFe<sub>2sub>As>2sub>, with different degrees of strain introduced by grinding and annealing. At the base temperature, in the antiferromagnetic/orthorhombic phase, compared to a sharp sextet Mssbauer spectrum of single crystal CaFe<sub>2sub>As>2sub>, which is taken as an un-strained sample, an obviously broadened sextet and an extra doublet were observed for ground CaFe<sub>2sub>As>2sub> powders with different degrees of strain. The Mssbauer results suggest that the magnetic phase transition of CaFe<sub>2sub>As>2sub> can be inhomogeneously suppressed by the grinding induced strain to such an extent that the antiferromagnetic order in parts of the grains forming the powdered sample remain absent all the way down to 4.6 K. However, strain has almost no effect on the temperature dependent hyperfine magnetic field in the grains with magnetic order. Additional electronic and asymmetry information was obtained from the isomer shift and quadrupole splitting. Similar isomer shift values in the magnetic phase for samples with different degrees of strain, indicate that the stain does not bring any significant variation of the electronic density at 57Fe nucleus position. As a result, the absolute values of quadrupole shift in the magnetic phase decrease and approach zero with increasing degrees of strain, indicating that the strain reduces the average lattice asymmetry at Fe atom position.

  5. Growth of large-domain YBa{sub 2}Cu{sub 3}O{sub x} with new seeding crystals of CaNdAlO{sub 4} and SrLaGaO{sub 4}.

    SciTech Connect (OSTI)

    Shi, D.; Hull, J. R.; LeBlanc, D.; LeBlanc, M. A. R.; Dabkowski, A.; Chang, Y.; Jiang, Y.; Zhang, Z.; Fan, H.; Energy Technology; Univ. of Cincinnati; Univ. of Ottawa; McMaster Univ.; Chinese Academy of Sciences

    1995-05-10

    Single crystals of CaNdAlO{sub 4} and SrLaGaO{sub 4} were used as seeds to grow large domains of YBa{sub 2}Cu{sub 3}O{sub x} for levitation applications. These crystals have high melting temperatures (> 1500 C) and similar lattice structures to that of YBa{sub 2}Cu{sub 3}O{sub x}. In a seeded melt-texturing method developed previously, the single crystals of CaNdAlO{sub 4}, SrLaGaO{sub 4}, and NdBa{sub 2}Cu{sub 3}O{sub x} were used as seeds for comparison. After melt processing, scanning electron microscopy analysis did not reveal any major differences in all these seeded melt-textured samples. However, the levitation forces in the samples seeded with single crystals of CaNdAlO{sub 4} and SrLaGaO{sub 4} increased considerably compared to that of the sample seeded with NdBa{sub 2}Cu{sub 3}O{sub x}. A model is proposed to describe the domain growth mechanism during seeded melt processing.

  6. Chemical stability of melt-cast refractories in K/sub 2/S/sub 2/O/sub 7/-V/sub 2/O/sub 5/ melt

    SciTech Connect (OSTI)

    Abanin, V.I.; Federov, A.A.; Malyavin, A.G.; Ketov, A.N.

    1983-02-20

    Melts based on V/sub 2/O/sub 5/ are promising as catalysts for conversion of sulfur dioxide and thermocatalytic decomposition of spent sulfuric acid. The high chemical activity of such media with respect to metallic materials necessitates development of new materials of construction not based on metals. The purpose of the present work was to study the influence the composition and structure of melt-cast refractories on their chemical stability in K/sub 2/S/sub 2/O/sub 7/-V/sub 2/O/sub 5/ melts. The chemical stability of refractories based on SiO/sub 2/ in K/sub 2/S/sub 2/O/sub 7/-V/sub 2/O/sub 5/ melt is raised by the presence of chain calcium silicates with pyroxene and pyroxenoid chains, and lowered in presence of the oxides of zirconium, zinc, and cobalt in the materials. Fused quartz, cor-93, cast stone of diopside composition, and basalt-dolomite cast stone have high chemical stability in K/sub 2/S/sub 2/O/sub 7/-V/sub 2/O/sub 5/ melt and can be recommended as construction materials for equipment used for thermocatalytic decomposition of spent sulfuric acid.

  7. High Schottky barrier at grain boundaries observed in Na{sub 1/2}Sm{sub 1/2}Cu{sub 3}Ti{sub 4}O{sub 12} ceramics

    SciTech Connect (OSTI)

    Somphan, Weeraya; Thongbai, Prasit; Yamwong, Teerapon; Maensiri, Santi

    2013-10-15

    Graphical abstract: - Highlights: NSCTO exhibits a high ?? of 7.08.4 10{sup 3} and low tan ? of 0.0300.041. NSCTO exhibits a high E{sub b} of ?2208 V cm{sup ?1} and large ? of 15.6. Giant ?? response is attributed to the electrically heterogeneous microstructure. High ?{sub b} values at grain boundaries are found to be 0.9250.964 eV. Formation of a potential barrier at grain boundaries is caused by Schottky effect. - Abstract: The dielectric properties and nonlinear currentvoltage characteristics of Na{sub 1/2}Sm{sub 1/2}Cu{sub 3}Ti{sub 4}O{sub 12} ceramics prepared by a conventional solid state reaction method were investigated. Na{sub 1/2}Sm{sub 1/2}Cu{sub 3}Ti{sub 4}O{sub 12} ceramics exhibited a high dielectric permittivity of 7.08.4 10{sup 3} and low loss tangent (tan ??0.0300.041). Non-Ohmic properties with a high breakdown voltage of ?2208 V cm{sup ?1} and large nonlinear coefficient of 15.6 were observed in Na{sub 1/2}Sm{sub 1/2}Cu{sub 3}Ti{sub 4}O{sub 12} ceramics. Using complex impedance analysis, Na{sub 1/2}Sm{sub 1/2}Cu{sub 3}Ti{sub 4}O{sub 12} ceramics were shown to be electrically heterogeneous consisting of semiconducting grains and insulating grain boundaries. Giant dielectric properties were described based on the electrically heterogeneous microstructure. X-ray photoelectron spectroscopy analysis suggested that the semiconductive nature of grains may be related to the presence of Cu{sup +} and Ti{sup 3+}. The formation of an electrostatic potential barrier at the grain boundaries of Na{sub 1/2}Sm{sub 1/2}Cu{sub 3}Ti{sub 4}O{sub 12} ceramics was suggested to be caused by the Schottky effect. Interestingly, high electrostatic potential barriers at grain boundaries in Na{sub 1/2}Sm{sub 1/2}Cu{sub 3}Ti{sub 4}O{sub 12} ceramics were calculated and found to be 0.9250.964 eV.

  8. Improvement of the physical properties of novel (1 ? y) Co{sub 0.8}Cu{sub 0.2}Fe{sub 2}O{sub 4} + (y) SrTiO{sub 3} nanocomposite

    SciTech Connect (OSTI)

    Ahmed, M.A.; Mansour, S.F.; Abdo, M.A.

    2013-05-15

    Graphical abstract: The ME coefficient as a function of magnetic field for the composites (1 ? y) Co{sub 0.8}Cu{sub 0.2}Fe{sub 2}O{sub 4} + (y) SrTiO{sub 3} (y = 40, 50, 60 and 80%). Highlights: ? T{sub C} and M{sub s} decrease with the increase of SrTiO{sub 3} concentration. ? The PE hysteresis loops were observed for all compositions. ? The maximum ME coefficient was observed for the composite with 60% SrTiO{sub 3}. - Abstract: Magnetoelectric (ME) nanocomposites (1 ? y) Co{sub 0.8}Cu{sub 0.2}Fe{sub 2}O{sub 4} + (y) SrTiO{sub 3} (y = 40, 50, 60, 80 and 100%) were prepared by standard ceramic method. Phase formation was checked using X-ray diffraction analysis. Both saturation magnetization (M{sub s}) and Curie temperature (T{sub C}) decrease with increasing SrTiO{sub 3} content. Temperature dependence of the dielectric constant reveals two maxima, one about 550 K corresponds to non-stoichiometry and lattice distortions while the second around 900 K corresponds to the Curie temperature (T{sub C}). The large value of ME output is due to the strain induced by lattice distortion in the ferrite phase by JahnTeller ions like Cu. Hence, JahnTeller effect in the ferrite leads to polarization in the piezoelectric phase.

  9. Calorimetric, spectroscopic and structural investigations of phase polymorphism in [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3}. Part I

    SciTech Connect (OSTI)

    Dolega, Diana; Mikuli, Edward; Inaba, Akira; Gorska, Natalia; Holderna-Natkaniec, Krystyna; Nitek, Wojciech

    2013-01-15

    Four crystalline phases of the coordination compound [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3} are identified by adiabatic calorimetry. Three phase transitions, one at T{sub C3}(IV{yields}III)=30.7 K, the second at T{sub C2}(III{yields}II)=91.7 K (both accompanied by comparable entropy changes 3.0 and 3.1 J K{sup -1} mol{sup -1}, respectively) and the third at T{sub C1}(II{yields}I)=241.6 K (accompanied by an entropy change of 8.1 J K{sup -1} mol{sup -1}) were discovered. X-ray single crystal diffraction (at 293 K) demonstrates that phase I is a highly dynamic disordered cubic phase (Fm3{sup Macron }m, No. 225) with two types of BF{sub 4}{sup -} anions differing in a degree of disorder. In phase II (at 170 K) the structure remains cubic (Ia3{sup Macron }, No. 206), with two different types of cations and four different types of anions. Splitting of certain IR bands connected with NH{sub 3} ligands at the observed phase transitions suggests a lowering of the symmetry of the [Ru(NH{sub 3}){sub 6}]{sup 3+} complex cation. Both NH{sub 3} ligands and BF{sub 4}{sup -} anions perform fast reorientations ({tau}{sub R} Almost-Equal-To 10{sup -12} s), which are significantly slowed down below the phase transition at T{sub C3}. {sup 1}H NMR studies led to estimate the values of the activation energy of NH{sub 3} ligands reorientation in the phases II and I as equal to {approx}8 kJ mol{sup -1}. In phase I the whole hexammineruthenium(III) cations reorientation as a tumbling process can be noticed. The activation energy value of this motion is {approx}24 kJ mol{sup -1}. {sup 19}F NMR studies give the values of the activation energy of BF{sub 4}{sup -} anions reorientation as {approx}6 kJ mol{sup -1}. Above the phase transition temperature half of BF{sub 4}{sup -} anions perform a tumbling motion with E{sub a} Almost-Equal-To 8 kJ mol{sup -1}. - Graphical abstract: A series of complementary methods, such as Adiabatic Calorimetry, Differential Scanning Calorimetry, Fourier Transform-Far and Middle Spectroscopy, proton and fluorine Nuclear Magnetic Resonance and structural methods reveal information about phase transitions in [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3}. Highlights: Black-Right-Pointing-Pointer Three novel phase transitions are found in [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3}. Black-Right-Pointing-Pointer The thermodynamic parameters of the phase transitions are derived. Black-Right-Pointing-Pointer The transitions are of order-disorder type. Black-Right-Pointing-Pointer The complex belongs to Fm3{sup Macron }m at 293 K and its symmetry changes to Ia3{sup Macron} at 170 K. Black-Right-Pointing-Pointer [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3} is a highly dynamically disordered crystal.

  10. Lanthanum pyrochlores and the effect of yttrium addition in the systems La{sub 2-x}Y{sub x}Zr{sub 2}O{sub 7} and La{sub 2-x}Y{sub x}Hf{sub 2}O{sub 7}

    SciTech Connect (OSTI)

    Whittle, Karl R. Cranswick, Lachlan M.D.; Redfern, Simon A.T.; Swainson, Ian P.; Lumpkin, Gregory R.

    2009-03-15

    The crystal structures of the compounds La{sub 2-x}Y{sub x}Zr{sub 2}O{sub 7} and La{sub 2-x}Y{sub x}Hf{sub 2}O{sub 7} with x=0.0, 0.4, 0.8, 1.2, 1.6, and 2.0 have been studied using neutron powder diffraction and electron microscopy to determine the stability fields of the pyrochlore and fluorite solid solutions. The limits of pyrochlore stability in these solid solutions are found to be close to La{sub 0.8}Y{sub 1.2}Zr{sub 2}O{sub 7} and La{sub 0.4}Y{sub 1.6}Hf{sub 2}O{sub 7}, respectively. In both systems the unit cell parameter is found to vary linearly with Y content across those compositions where the pyrochlore phase is stable, as does the x-coordinate of the oxygen atoms on the 48f (x,3/8 ,3/8 ) sites. In both systems, linear extrapolations of the pyrochlore data suggest that the disordering is accompanied by a small decrease in the lattice parameter of approximately 0.4%. After the pyrochlore solid solution limit is reached, a sharp change is observed from x{approx}0.41 to 0.375 as the disordered defect fluorite structure is favoured. Electron diffraction patterns illustrate that some short-range order remains in the disordered defect fluorite phases. - Graphical abstract: Short-range ordering has been seen in the defect fluorites Y{sub 2}Zr{sub 2}O{sub 7} and Y{sub 2}Hf{sub 2}O{sub 7}, where they previously were thought to be entirely disordered. Evidence suggests the correlation length changes with composition, but is not commensurate with unit cell sizes.

  11. Evaluating Impacts of CO<sub>2sub> Intrusion into an Unconsolidated Aquifer. I. Experimental Data

    SciTech Connect (OSTI)

    Lawter, Amanda R.; Qafoku, Nikolla; Wang, Guohui; Shao, Hongbo; Brown, Christopher F.

    2015-08-04

    Capture and deep subsurface sequestration of CO<sub>2sub> has been identified as a potential mitigation technique for rising atmospheric CO<sub>2sub> concentrations. Sequestered CO<sub>2sub> represents a potential risk to overlying aquifers if the CO<sub>2sub> leaks from the deep storage reservoir. Batch and column experiments combined with wet chemical extractions were conducted to evaluate these risks to groundwater quality and to understand effects of CO<sub>2sub> leakage on aquifer chemistry and mineralogy. Sediments from the High Plains aquifer in Kansas, a confined sandstone aquifer, were used to study time-dependent release of major, minor and trace elements when exposed to CO<sub>2sub> gas. Results showed that Ca, Ba, Si, Mg, Sr, Na, and K increased either instantaneously or followed nonlinear increasing trends with time, indicating dissolution and/or desorption reactions controlled their release. Other elements, such as Mn and Fe, were also released from all sediments, creating a potential for redox reactions to occur. Results from acid extractions confirmed sediments had appreciable amounts of contaminants that may potentially be released into the aqueous phase. However, results from the batch and column experiments demonstrated that only a few trace elements (e.g., As, Cu, Cr, Pb) were released, indicating the risk of groundwater quality degradation due to exposure to leakage of sequestered CO<sub>2sub> is low. Concentrations of Mo were consistently higher in the control experiments (absence of CO<sub>2sub>) and were below detection in the presence of CO<sub>2sub> indicating a possible benefit of CO<sub>2sub> in groundwater aquifers. These investigations will provide useful information to support site selection, risk assessment, and public education efforts associated with geological CO<sub>2sub> storage and sequestration.

  12. CO<sub>2sub> hydrogenation to formate and methanol as an alternative to photo- and electrochemical CO<sub>2sub> reduction

    SciTech Connect (OSTI)

    Wang, Wan -Hui; Himeda, Yuichiro; Muckerman, James T.; Manbeck, Gerald F.; Fujita, Etsuko

    2015-09-03

    In this study, carbon dioxide is one of the end products of combustion, and is not a benign component of the atmosphere. The concentration of CO<sub>2sub> in the atmosphere has reached unprecedented levels and continues to increase owing to an escalating rate of fossil fuel combustion, causing concern about climate change and rising sea levels. In view of the inevitable depletion of fossil fuels, a possible solution to this problem is the recycling of carbon dioxide, possibly captured at its point of generation, to fuels. Researchers in this field are using solar energy for CO<sub>2sub> activation and utilization in several ways: (i) so-called artificial photosynthesis using photo-induced electrons; (ii) bulk electrolysis of a CO<sub>2sub> saturated solution using electricity produced by photovoltaics; (iii) CO<sub>2sub> hydrogenation using solar-produced H<sub>2sub>; and (iv) the thermochemical reaction of metal oxides at extremely high temperature reached by solar collectors. Since the thermodynamics of CO<sub>2sub> at high temperature (> 1000 ºC) are quite different from those near room temperature, only chemistry below 200 ºC is discussed in this review.

  13. Magnetic properties of CuFe{sub 1−x}Cr{sub x}O{sub 2} nanoparticles surrounded by amorphous SiO{sub 2}

    SciTech Connect (OSTI)

    Mori, K.; Hachisu, M.; Yamazaki, T.; Ichiyanagi, Y.

    2015-05-07

    CuFe{sub 1−x}Cr{sub x}O{sub 2} (0 ≤ x ≤ 1.0) nanoparticles surrounded by amorphous SiO{sub 2} with an average diameter of 30–50 nm were synthesized using a wet chemical method. The annealing temperatures were controlled to yield various sizes of single-phase CuFe{sub 1−x}Cr{sub x}O{sub 2} nanoparticles. CuFeO{sub 2} bulk crystal is known to have a multiferroic delafossite structure with two Néel temperatures of 11 and 14 K; however, the transition temperature shifted higher as the Cr–ion doping level increased. In addition, the lattice constants decreased in accordance with increased Cr-ion doping, which was confirmed by X-ray diffraction measurements. The magnetization curves showed weak ferromagnetic behavior and no coercivity was observed. Hence, frustration in the triangular lattice of the delafossite structure can be released by Cr–ion doping and higher magnetization can be expected. A fine structure analysis through X-ray absorption fine structure measurements was also conducted. It was found that the structure of the Cu ion is similar to that of Cu{sub 2}O, and the c axis of the CuFe{sub 1−x}Cr{sub x}O{sub 2} should be shortened by the Cr–ion doping.

  14. Spin-orbit tuned metal-insulator transitions in single-crystal Sr?Ir<sub>1xsub>Rhx>O? (0?x?1)

    SciTech Connect (OSTI)

    Qi, T. F.; Korneta, O. B.; Li, L.; Butrouna, K.; Cao, V. S.; Wan, Xiangang; Schlottmann, P.; Kaul, R. K.; Cao, G.

    2012-09-06

    Sr?IrO? is a magnetic insulator driven by spin-orbit interaction (SOI) whereas the isoelectronic and isostructural Sr?RhO? is a paramagnetic metal. The contrasting ground states have been shown to result from the critical role of the strong SOI in the iridate. Our investigation of structural, transport, magnetic, and thermal properties reveals that substituting 4d Rh?? (4d?) ions for 5d Ir?? (5d?) ions in Sr?IrO? directly reduces the SOI and rebalances the competing energies so profoundly that it generates a rich phase diagram for Sr?Ir<sub>1xsub>Rhx>O? featuring two major effects: (1) Light Rh doping (0 ? x ? 0.16) prompts a simultaneous and precipitous drop in both the electrical resistivity and the magnetic ordering temperature TC, which is suppressed to zero at x = 0.16 from 240 K at x = 0. (2) However, with heavier Rh doping [0.24 < x < 0.85 (0.05)] disorder scattering leads to localized states and a return to an insulating state with spin frustration and exotic magnetic behavior that only disappears near x = 1. The intricacy of Sr?Ir<sub>1xsub>Rhx>O? is further highlighted by comparison with Sr?Ir<sub>1xsub>Rux>O? where Ru?? (4d?) drives a direct crossover from the insulating to metallic states.

  15. A novel broadband emission phosphor Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} for white light emitting diodes

    SciTech Connect (OSTI)

    Li, Junfu; Qiu, Kehui; Li, Junfeng; Li, Wei; Yang, Qian; Li, Junhan

    2010-05-15

    A novel broadband emission phosphor Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} was first synthesized by solution combustion method. The X-ray diffraction showed that Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} phase can be obtained at 600-900 {sup o}C through combustion route. The crystal structure of this material was refined by Rietveld method using powder X-ray diffraction. It crystallizes in cubic system and belongs to space group Ia3d with z = 8, a = 0.12500 nm. The excitation band of Ca{sub 2}KMg{sub 2}V{sub 3}O{sub 12} peaks at 320 nm in a region between 260 nm and 425 nm, and the emission spectrum exhibits an intense band centered at about 528 nm covering from 400 nm to 800 nm. The colour coordinates of samples prepared at different ignition temperatures are in a range of x = 0.323-0.339, y = 0.430-0.447.

  16. Tunable Polarity Behavior and Self-Driven Photoswitching in p-WSe<sub>2sub>/n-WS>2sub> Heterojunctions

    SciTech Connect (OSTI)

    Huo, Nengjie; Yang, Juehan; Huang, Le; Wei, Zhongming; Li, Shu-Shen; Wei, Su-Huai; Li, Jingbo

    2015-08-21

    In Van der Waals (vdW) p–n heterojunctions consisting of various 2D layer compounds are fascinating new artificial materials that can possess novel physics and functionalities enabling the next-generation of electronics and optoelectronics devices. Here, it is reported that the WSe<sub>2sub>/WS>2sub> p–n heterojunctions perform novel electrical transport properties such as distinct rectifying, ambipolar, and hysteresis characteristics. Intriguingly, the novel tunable polarity transition along a route of n-“anti-bipolar”–p-ambipolar is observed in the WSe<sub>2sub>/WS>2sub> heterojunctions owing to the successive work of conducting channels of junctions, p-WSe<sub>2sub> and n-WS<sub>2sub> on the electrical transport of the whole systems. Moreover, the type-II band alignment we obtained from first principle calculations and built-in potential in this vdW heterojunction can also facilitate the efficient electron–hole separation, thus enabling the significant photovoltaic effect and a much enhanced self-driven photoswitching response in this system.

  17. Interfacial mode coupling as the origin of the enhancement of T<sub>c> in FeSe films on SrTiO<sub>3sub>

    SciTech Connect (OSTI)

    Lee, J. J.; Schmitt, F. T.; Moore, R. G.; Johnston, S.; Cui, Y. -T.; Li, W.; Yi, M.; Liu, Z. K.; Hashimoto, M.; Zhang, Y.; Lu, D. H.; Devereaux, T. P.; Lee, D. -H.; Shen, Z. -X.; /SIMES, Stanford /SLAC /Stanford U., Geballe Lab.

    2014-11-12

    Films of iron selenide (FeSe) one unit cell thick grown on strontium titanate (SrTiO<sub>3sub> or STO) substrates have recently shown superconducting energy gaps opening at temperatures close to the boiling point of liquid nitrogen (77 K), which is a record for the iron-based superconductors. The gap opening temperature usually sets the superconducting transition temperature T<sub>c>, as the gap signals the formation of Cooper pairs, the bound electron states responsible for superconductivity. To understand why Cooper pairs form at such high temperatures, we examine the role of the SrTiO<sub>3sub> substrate. Here we report high-resolution angle-resolved photoemission spectroscopy results that reveal an unexpected characteristic of the single-unit-cell FeSe/SrTiO<sub>3sub> system: shake-off bands suggesting the presence of bosonic modes, most probably oxygen optical phonons in SrTiO<sub>3sub>, which couple to the FeSe electrons with only a small momentum transfer. Such interfacial coupling assists superconductivity in most channels, including those mediated by spin fluctuations. Our calculations suggest that this coupling is responsible for raising the superconducting gap opening temperature in single-unit-cell FeSe/SrTiO<sub>3sub>.

  18. White light generation from Dy{sup 3+}-doped ZnO-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} glasses

    SciTech Connect (OSTI)

    Jayasimhadri, M.; Jang, Kiwan; Lee, Ho Sueb; Chen, Baojiu; Yi, Soung-Soo; Jeong, Jung-Hyun

    2009-07-01

    Dysprosium doped ZnO-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} (ZBP) glasses were prepared by a conventional melt quenching technique in order to study the luminescent properties and their utility for white light emitting diodes (LEDs). X-ray diffraction spectra revealed the amorphous nature of the glass sample. The present glasses were characterized by infrared and Raman spectra to evaluate the vibrational features of the samples. The emission and excitation spectra were reported for the ZBP glasses. Strong blue (484 nm) and yellow (574 nm) emission bands were observed upon various excitations. These two emissions correspond to the {sup 4}F{sub 9/2}->{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}->{sup 6}H{sub 13/2} transitions of Dy{sup 3+} ions, respectively. Combination of these blue and yellow bands gives white light to the naked eye. First time, it was found that ZnO-B{sub 2}O{sub 3}-P{sub 2}O{sub 5} glasses efficiently emit white light under 400 and 454 nm excitations, which are nearly match with the emissions of commercial GaN blue LEDs and InGaN LED, respectively. CIE chromaticity coordinates also calculated for Dy{sup 3+}: ZBP glasses to evaluate the white light emission.

  19. Characterization of collision cascade damage in Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} by HRTEM

    SciTech Connect (OSTI)

    Weber, W.J.; Wang, L.M.

    1994-12-01

    Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} thin crystals become amorphous under ion beam irradiation. The ion dose required for complete amorphization of the thin crystal (critical amorphization dose, D{sub c}) increased with the increasing irradiation temperature and decreased with ion mass at elevated temperatures. Samples irradiated with 1-1.5 MeV Ar{sup +}, Kr{sup +} and Xe{sup +} ions to doses much lower than Dc, in the temperature range from 20 to 498 K were used for a detailed HRTEM study to better understand the amorphization process. The residual collision cascade damage after irradiation appeared as manometer scale amorphous domains. The images of these domains are extremely sensitive to the sample thickness. Small domains of cascade size were only found at the very thin edge of the sample. In thicker regions, amorphous domains appear after higher doses as the result of cascade overlap in projection. At higher temperatures, the observed amorphous domains are smaller indicating thermal recovery at the amorphous/crystalline interface. The amorphous domains are also larger in size after irradiation with ions of higher mass at a fixed ion dose. These results are consistent with the Dc-temperature curves determined by in situ TEM with the HVEM-Tandem Facility at Argonne National Laboratory. The width of the amorphous rim along the edge of the specimen grew with increasing ion dose suggesting that amorphization also proceeds from the sample surface. Images of the collision cascade damage were compared to the cascade sizes calculated with the TRIM code. Some digitally acquired HRTEM images of the cascade damage were processed to reveal more detailed information.

  20. Solid solubilities of (La Nd,){sub 2}(Zr,Ti){sub 2}O{sub 7} phases deduced by neutron diffraction

    SciTech Connect (OSTI)

    Harvey, Elizabeth J.; Whittle, Karl R.; Lumpkin, Gregory R.; Smith, Ronald I.; Redfern, Simon A.T. . E-mail: satr@cam.ac.uk

    2005-03-15

    Time-of-flight powder neutron diffraction has been performed on oxides with composition (La{sub 1-x}Nd{sub x}){sub 2}Zr{sub 2}O{sub 7} and Nd{sub 2}(Zr{sub 1-x}Ti{sub x}){sub 2}O{sub 7}, where x=0, 0.2, 0.4,...1.0, in order to determine the solid solution behaviour across each series. Between La{sub 2}Zr{sub 2}O{sub 7} and Nd{sub 2}Zr{sub 2}O{sub 7}, a cubic pyrochlore phase is observed (Fd3-bar m, Z=8). A linear decrease in the lattice parameter from 10.8047 to 10.6758A indicates complete miscibility of the two end-members. For the same series, the 48f oxygen x-parameter increases from 0.3313 to 0.3348, suggesting increased distortion of the 6 coordinate B sites and reduced distortion of the 8 coordinate A sites. There is limited solubility of Nd{sub 2}Ti{sub 2}O{sub 7} in Nd{sub 2}Zr{sub 2}O{sub 7}. Exsolution of a monoclinic phase (P2{sub 1}, Z=8) rich in Nd{sub 2}Ti{sub 2}O{sub 7} is observed at approximately x=0.56. The compositional range over which a solid solution exists is more extensive than that which has been previously reported. The solubility of Nd{sub 2}Zr{sub 2}O{sub 7} in Nd{sub 2}Ti{sub 2}O{sub 7} is very low.

  1. Photoluminescence in Pb{sub 0.95}Sr{sub 0.05}(Zr{sub 1?x}Ti{sub x}){sub 1?y}Cr{sub y}O{sub 3} ferroelectric ceramic system

    SciTech Connect (OSTI)

    Hernndez-Garca, M.; Costa-Marrero, J.; Durruthy-Rodrguez, M. D.; Caldern-Piar, F.; Guerra, J. D. S.; Yaez-Limn, J. M.

    2014-07-28

    Over the past several years, there has been a remarkable growth and development in new ceramic and/or composite materials to be used in the electro-electronic industry. Ferroelectric materials have been recognized for their multifunctional physical properties; also, their optical properties are a subject of intense research effort due to their possible electro-optic applications. In this work, the visible photoluminescence effect is analyzed at room temperature in a sintered Pb{sub 0.95}Sr{sub 0.05}(Zr{sub 1?x}Ti{sub x}){sub 1?y}Cr{sub y}O{sub 3} perovskite-type structure system, doped with Sr and Cr. The excitation bands used were 267, 325, 373, 457, 635, and 680?nm, but the best result was obtained at 373?nm. The intensity and energy of such emission in this system have been studied by changing the molar Cr concentration (0?

  2. Biotic and Abiotic Transformation of a Volatile Organics Plume in a Semi-Arid Vadose Zone

    SciTech Connect (OSTI)

    Studer, J.E.; Singletary, M.A.; Miller, D.R.

    1999-04-08

    An evaluation of biotic and abiotic attenuation processes potentially important to chlorinated and non-chlorinated volatile organic compound (VOC) fate and transport in the 148 meter thick vadose zone beneath the Chemical Waste Landfill (CWL) was conducted. A unique feature of this evaluation is the comparison of two estimates of VOC mass present in the soil gas, pore-water, and solid phases (but not including mass as non-aqueous phase liquid [NAPL]) of the vadose zone in 1993. One estimate, 1,800 kg, was obtained from vadose zone transport modeling that incorporated molecular diffusion and volatilization to the atmosphere, but not biotic or chemical processes. The other estimate, 2,120 kg, was obtained from the sum of VOC mass physically removed during soil vapor extraction and an estimate of VOC mass remaining in the vadose zone in 1998, both adjusted to exclude NAPL mass. This comparison indicates that biogeochemical processes were at best slightly important to historical VOC plume development. Some evidence of aerobic degradation of non-chlorinated VOCs and abiotic transformation of 1,1,1-Trichloroethane was identified. Despite potentially amenable site conditions, no evidence was found of cometabolic and anaerobic transformation pathways. Relying principally on soil-gas analytical results, an upper-bound estimate of 21% mass reduction due to natural biogeochemical processes was developed. Although available information for the CWL indicates that natural attenuation processes other than volatilization to the atmosphere did not effective y enhance groundwater protection, these processes could be important in significantly reducing groundwater contamination and exposure risks at other sites. More laboratory and field research is required to improve our collective ability to characterize and exploit natural VOC attenuation processes, especially with respect to the combination of relatively thick and dry vadose zones and chlorinated VOCs.

  3. Preparation and photocatalytic activity for water splitting of Pt-Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays

    SciTech Connect (OSTI)

    Liu, Jing; Liu, Jiawen; Li, Zhonghua

    2013-02-15

    Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays were prepared by hydrothermal method from Ta{sub 2}O{sub 5} nanotube arrays, obtained by anodization of Ta foils, in Na{sub 2}CO{sub 3} solution at 150 Degree-Sign C. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-vis diffuse reflectance spectra (UV-DRS) and X-ray photoelectron spectroscopy (XPS). Analysis results show that pyrochlore structure Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays have been successfully fabricated. The diameters and lengths of Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays are 50 nm and 4 {mu}m, respectively. The photocatalytic hydrogen production activities of the as-synthesized Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays are highly dependent on the hydrothermal reaction time and Na{sub 2}CO{sub 3} concentration, optimized reaction parameters are obtained. To further improve the photocatalytic activity for hydrogen evolution, Pt loaded Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays are prepared by photochemical reduction method. The Pt loaded samples exhibit much higher activity for hydrogen evolution than pure Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays. Moreover, the photocatalytic hydrogen properties are rather stable. - Graphical abstract: Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays were synthesized by hydrothermal method using Ta{sub 2}O{sub 5} nanotube arrays as a precursor. The loaded Pt enhances the photocatalytic activity for water splitting of Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays. Highlights: Black-Right-Pointing-Pointer Novel Na{sub 2}Ta{sub 2}O{sub 6} nanotube array films with pyrochlore structure were synthesized. Black-Right-Pointing-Pointer Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays are active for H{sub 2} evolution from aqueous CH{sub 3}OH solution. Black-Right-Pointing-Pointer The effect of hydrothermal conditions on photocatalytic activity was investigated. Black-Right-Pointing-Pointer Pt loading can improve the photocatalytic activities of Na{sub 2}Ta{sub 2}O{sub 6} nanotube arrays. Black-Right-Pointing-Pointer Photocatalytic mechanism is proposed based on the experimental results.

  4. Kondo hole behavior in Ce{sub 0.97} La{sub 0.03}Pd{sub 3}

    SciTech Connect (OSTI)

    Lawrence, J.M.; Graf, T.; Hundley, M.F.; Mandrus, D.; Thompson, J.D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Lacerda, A.; Torikachvili, M.S. [National High Magnetic Field Laboratory, Pulse Facility, Los Alamos, New Mexico 87545 (United States)] [National High Magnetic Field Laboratory, Pulse Facility, Los Alamos, New Mexico 87545 (United States); Sarrao, J.L.; Fisk, Z. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306 (United States)] [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306 (United States)

    1996-05-01

    We present results for the resistivity, the magnetoresistance, and the specific heat of Ce{sub 0.97}La{sub 0.03}Pd{sub 3} and CePd{sub 3}. The impurity contributions to these measurements follow the predictions of the single-impurity Kondo model for a Kondo temperature {ital T}{sub {ital L}}{approx_equal}65 K, assuming that the impurity behaves as a crystal-field split ({Gamma}{sub 7}) doublet. Assuming a {ital J}=5/2 impurity, the value of {ital T}{sub {ital L}} needed to fit these experiments varies from 65 to 125 K. The contribution to the susceptibility may be too small to be explained by the model. These results address whether the nonmagnetic impurity behaves as a Kondo hole. {copyright} {ital 1996 The American Physical Society.}

  5. Optical spectroscopic study of inverted cylindrical magnetron sputtering of YBa sub 2 Cu sub 3 O sub 7 minus x

    SciTech Connect (OSTI)

    Xi, X.X.; Wu, X.D.; Inam, A.; Li, Q.; Hemmick, D.; Findikoglu, A. ); Venkatesan, T.; Chang, C.C. ); Howard, R. )

    1990-07-02

    Optical spectroscopic studies of the plasma generated by inverted cylindrical magnetron sputtering of the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} reveal strong ionic emissions from cation elements as well as from the sputter gases. The emissions of cationic ions are weakened drastically when O{sub 2} is added into the sputter gas indicating the dominating role of ions in the reaction with oxygen to form gas phase oxides. The formation of gas phase oxides is proposed to be an important precursor step for the {ital in} {ital situ} deposition of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} thin films.

  6. Analysis of volatile organic compounds in groundwater samples by gas chromatography-mass spectrometry

    SciTech Connect (OSTI)

    Bernhardt, J.

    1995-08-23

    The Savannah River Site contains approximately 1500 monitoring wells from which groundwater samples are collected. Many of these samples are sent off-site for various analyses, including the determination of trace volatile organic compounds (VOCs). This report describes accomplishments that have been made during the past year which will ultimately allow VOC analysis to be performed on-site using gas chromatography-mass spectrometry. Through the use of the on-site approach, it is expected that there will be a substantial cost savings. This approach will also provide split-sample analysis capability which can serve as a quality control measure for off-site analysis.

  7. Photo-activated luminescence sensor and method of detecting trichloroethylene and related volatile organochloride compounds

    DOE Patents [OSTI]

    Dinh, T.V.

    1996-06-11

    A sensor for detecting trichloroethylene and related volatile organochloride compounds uses a photo-activator that produces a photo-product complex with the contaminant. Characteristics of the light emitted from the complex will indicate the presence of the contaminant. A probe containing the photo-activator has an excitation light interface and a contaminant interface. One particular embodiment uses a porous membrane as the contaminant interface, so that the contaminant can migrate there through to the photo-activator and thereby form the complex. 23 figs.

  8. NMED COMMENTS ITEM 3 REVISE VOLATILE ORGANIC COMPOUND (VOC) TARGET ANALYTE LIST

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    3 NMED COMMENTS ITEM 3 REVISE VOLATILE ORGANIC COMPOUND (VOC) TARGET ANALYTE LIST OTHER CHANGES TO VOC MONITORING PROGRAM Page 1 of 21 VOC 3*1: PMR Section 3, Topic 1, Table 1 Recalculated Waste Matrix Code Group Weighting Factors based on the 2004 Compliance Recertification Contact Handled (CH) Transuranic (TRU) Waste Inventory (m 3 ) The new weighting factors appear to be based on CH TRU waste only and do not include remote handled (RH) TRU waste. There was no discussion in the PMR addressing

  9. Photo-activated luminescence sensor and method of detecting trichloroethylene and related volatile organochloride compounds

    DOE Patents [OSTI]

    Dinh, Tuan V.

    1996-01-01

    A sensor for detecting trichloroethylene and related volatile organochloride compounds uses a photo-activator that produces a photo-product complex with the contaminant. Characteristics of the light emitted from the complex will indicate the presence of the contaminant. A probe containing the photo-activator has an excitation light interface and a contaminant interface. One particular embodiment uses a porous membrane as the contaminant interface, so that the contaminant can migrate therethrough to the photo-activator and thereby form the complex.

  10. Spatial resolution and the geologic interpretation of Martian morphology - implications for subsurface volatiles

    SciTech Connect (OSTI)

    Zimbelman, J.R.

    1987-08-01

    Viking Orbiter images of the Acheron Fossae on Mars are presented and analyzed, with an emphasis on the impact of image resolution on the interpretation. High-resolution (less than 10 m/pixel) images reveal small mounds which can be interpreted as aeolian dunes, but these features are not evident on images with resolution of 50 m/pixel or greater. Also reported are the results of a visual inspection of 527 usable high-resolution images: it is found that all of the morphological features identified can arise in the absence of subsurface volatiles. 21 references.

  11. Luminescence properties of a blue-emitting phosphor: (Sr{sub 1?x}Eu{sub x})Si{sub 9}Al{sub 19}ON{sub 31} (0

    SciTech Connect (OSTI)

    Liu, Lihong; Xie, Rong-Jun; Hirosaki, Naoto; Dierre, Benjamin; Sekiguchi, Takashi

    2013-11-15

    Blue-emitting Sr{sub 1?x}Eu{sub x}Si{sub 9}Al{sub 19}ON{sub 31} phosphors were synthesized at 1800 C for 2 h under 1 MPa N{sub 2} by using the gas-pressure sintering method (GPS). The microstructure, photoluminescence (PL) properties of the prepared phosphors were investigated. Under the 290 nm excitation, broad PL emission bands with peak positions at 448490 nm were detected. The concentration quenching was not observed owing to the large distance betweenEu{sup 2+} ions that made the nonradiative energy transfer between neighboring Eu{sup 2+} ions difficult. The blue phosphor generally showed a small thermal quenching at low Eu{sup 2+} concentrations. The absorption and external quantum efficiency of the synthesized Sr{sub 0.5}Eu{sub 0.5}Si{sub 9}Al{sub 19}ON{sub 31} were 85% and 62% upon the 365 nm excitation, respectively. The interesting PL results indicate that Sr{sub 1?x}Eu{sub x}Si{sub 9}Al{sub 19}ON{sub 31} has great potentials as a blue phosphor for white LEDs applications. - Graphical abstract: Sr{sub 0.7}Eu{sub 0.3}Si{sub 9}Al{sub 19}ON{sub 31} gives blue-emitting at 471 nm. Excitation spectrum is composed of five bands in the range of 250450 nm, which are matching well with emission wavelength of UV LEDs. Display Omitted - Highlights: Blue-emitting Sr{sub 1?x}Eu{sub x}Si{sub 9}Al{sub 19}ON{sub 31} phosphors were synthesized by gas-pressure sintering method. The concentration quenching was not observed in this phosphor. This blue phosphor generally showed a small thermal quenching at low Eu{sup 2+} concentrations. The absorption and external quantum efficiency of the synthesized Sr{sub 0.5}Eu{sub 0.5}Si{sub 9}Al{sub 19}ON{sub 31} were 85% and 62% upon the 365 nm excitation.

  12. Structural characterization and AC conductivity of bis tetrapropylammonium hexachlorado-dicadmate, [N(C{sub 3}H{sub 7}){sub 4}]{sub 2}Cd{sub 2}Cl{sub 6}

    SciTech Connect (OSTI)

    Hannachi, N.; Guidara, K.; Bulou, A.; Hlel, F.

    2010-11-15

    Synthesis, crystal structure, vibrational study, {sup 13}C, {sup 111}Cd CP-MAS-NMR analysis and electrical properties of the compound [N(C{sub 3}H{sub 7}){sub 4}]{sub 2}Cd{sub 2}Cl{sub 6}, are reported. The latter crystallizes in the triclinic system (space group P1-bar, Z = 2) with the following unit cell dimensions: a = 9.530(1) A, b = 11.744(1) A, c = 17.433(1) A, {alpha} = 79.31(1){sup o}, {beta} = 84.00(1){sup o} and {gamma} = 80.32(1){sup o}. Besides, its structure was solved using 6445 independent reflections down to R = 0.037. The atomic arrangement can be described by alternating organic and inorganic layers parallel to the (11-bar 0) plan, made up of tetrapropylammonium groups and Cd{sub 2}Cl{sub 6} dimers, respectively. In crystal structure, the inorganic layer, built up by Cd{sub 2}Cl{sub 6} dimers, is connected to the organic ones through van der Waals interaction in order to build cation-anion-cation cohesion. Impedance spectroscopy study, reported in the sample, reveals that the conduction in the material is due to a hopping process. The temperature and frequency dependence of dielectric constants of the single crystal sample has been investigated to determine some related parameters to the dielectric relaxation.

  13. Effect of externally applied pressure on the magnetic behavior of Cu{sub 2}Te{sub 2}O{sub 5}(Br{sub x}Cl{sub 1-x}){sub 2}

    SciTech Connect (OSTI)

    Crowe, S. J.; Lees, M. R.; Paul, D. M. K.; Bewely, R. I.; Taylor, J.; McIntyre, G.; Zaharko, O.; Berger, H.

    2006-04-01

    The effect of externally applied pressure on the magnetic behavior of Cu{sub 2}Te{sub 2}O{sub 5}(Br{sub x}Cl{sub 1-x}){sub 2} with x=0, 0.73, and 1, is investigated by a combination of magnetic susceptibility, neutron diffraction, and neutron inelastic scattering measurements. The magnetic transition temperatures of the x=0 and 0.73 compositions are observed to increase linearly with increasing pressure at a rate of 0.23(2) and 0.04(1) K/kbar, respectively. However, the bromide shows contrasting behavior with a large suppression of the transition temperature under pressure, at a rate of -0.95(9) K/kbar. In neutron inelastic scattering measurements of Cu{sub 2}Te{sub 2}O{sub 5}Br{sub 2} under pressure only a small change to the ambient pressure magnetic excitations were observed. A peak in the density of states was seen to shift from {approx}5 meV in ambient pressure to {approx}6 meV under an applied pressure of 11.3 kbar, which was associated with an increase in the overall magnetic coupling strength.

  14. 57Fe Mössbauer study of Lu<sub>2sub>Fe>3sub>Si>5 sub>iron silicide superconductor

    SciTech Connect (OSTI)

    Ma, Xiaoming; Ran, Sheng; Pang, Hua; Li, Fashen; Canfield, Paul C.; Bud'ko, Sergey L.

    2015-03-28

    With the advent of Fe–As based superconductivity it has become important to study how superconductivity manifests itself in details of 57Fe Mössbauer spectroscopy of conventional, Fe-bearing superconductors. The iron-based superconductor Lu<sub>2sub>Fe>3sub>Si>5sub> has been studied by 57Fe Mössbauer spectroscopy over the temperature range from 4.4 K to room temperature with particular attention to the region close to the superconducting transition temperature (T<sub>c>=6.1 K). Furthermore, consistent with the two crystallographic sites for Fe in this structure, the observed spectra appear to have a pattern consisting of two doublets over the whole temperature range. The value of Debye temperature was estimated from temperature dependence of the isomer shift and the total spectral area and compared with the specific heat capacity data. As a result, neither abnormal behavior of the hyperfine parameters at or near T<sub>c>, nor phonon softening were observed.

  15. K{sub 2}Fe{sub 2}B{sub 2}O{sub 7}: A transparent nonlinear optical crystal with frustrated magnetism

    SciTech Connect (OSTI)

    Wang Yonggang [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Li, R.K., E-mail: rkli@mail.ipc.ac.c [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-06-15

    A new noncentrosymmetric ferroborate crystal, K{sub 2}Fe{sub 2}B{sub 2}O{sub 7}, has been grown from high temperature melt. Structure solution from single crystal X-ray diffraction shows that the title compound crystallizes in a trigonal space group P321 with cell dimensions of a=8.7475(12) A and c=8.5124(17) A. In the structure, FeO{sub 4} tetrahedron shares its three basal oxygen atoms with BO{sub 3} triangles forming a two-dimensional layer in the ab plane and the layers are connected by the apical Fe-O bonds along the c direction. The crystal is transparent in the visible and near infrared region from 500 to 2000 nm with three pronounced absorption bands ascribed to d-d transitions of tetrahedrally coordinated Fe{sup 3+} ions. Though, structurally analog to K{sub 2}Al{sub 2}B{sub 2}O{sub 7}, the further twisting of the BO{sub 3} groups between adjacent layers reduces its optical nonlinearity to a second-harmonic generation intensity of about 0.4 times that of KDP. Spin-glass behavior is observed at 20 K which is probably due to geometrically magnetic frustration of the triangular Fe net in the ab plane. - Graphical abstract: Single crystal of a new ferroborate K{sub 2}Fe{sub 2}B{sub 2}O{sub 7}, space group P321, a=8.7475(3) A, c=8.5124(3) A, was obtained and characterized. It exhibits considerable SHG efficiency and frustrated magnetism originated from the triangular Fe net in the ab plane.

  16. Synthesis, characterization and magnetic property of a new 3D iron phosphite: |C{sub 4}N{sub 3}H{sub 14}|[Fe{sub 3}(HPO{sub 3}){sub 4}F{sub 2}(H{sub 2}O){sub 2}] with intersecting channels

    SciTech Connect (OSTI)

    Qiao Jian; Zhang Lirong; Yu Yang; Li Guanghua; Jiang Tianchan; Huo Qisheng; Liu Yunling

    2009-07-15

    A new open-framework iron (III) phosphite |C{sub 4}N{sub 3}H{sub 14}|[Fe{sub 3}(HPO{sub 3}){sub 4}F{sub 2}(H{sub 2}O){sub 2}] has been solvothermally synthesized by using diethylenetriamine (DETA) as the structure-directing agent. Single-crystal X-ray diffraction analysis reveals that the compound crystallizes in the monoclinic space group C2/c having unit cell parameters a=12.877(3) A, b=12.170(2) A, c=12.159(2) A, beta=93.99(3){sup o}, V=1900.9(7) A{sup 3}, and Z=4 with R{sub 1}=0.0447, wR{sub 2}=0.0958. The complex structure consists of HPO{sub 3} pseudo-tetrahedra and {l_brace}Fe{sub 3}O{sub 14}F{sub 2}{r_brace} trimer building units. The assembly of these building units generates 3D inorganic framework with intersecting 6-, 8-, and 10-ring channels. The DETA cations are located in the 10-ring channels linked by hydrogen bonds. The Moessbauer spectrum shows that there exhibit two crystallographically independent iron (III) atoms. And the magnetic investigation shows the presence of antiferromagnetic interactions. Further characterization of the title compound was performed using X-ray powder diffraction (XRD), infrared (IR) spectra, thermal gravimetric analyses (TGA), inductively coupled plasma (ICP) and elemental analyses. - Graphical abstract: A new three-dimensional iron phosphite with intersecting 6-, 8-, 10-ring channels has been solvothermally synthesized by using diethylenetriamine (DETA) as the structure-directing agent.

  17. Temperature driven transition from giant to tunneling magneto-resistance in Fe{sub 3}O{sub 4}/Alq{sub 3}/Co spin Valve: Role of Verwey transition of Fe{sub 3}O{sub 4}

    SciTech Connect (OSTI)

    Dey, P. Rawat, R.; Potdar, S. R.; Choudhary, R. J.; Banerjee, A.

    2014-05-07

    We demonstrate interface energy level engineering, exploiting the modification in energy band structure across Verwey transition temperature (T{sub V}) of Fe{sub 3}O{sub 4}, in a Fe{sub 3}O{sub 4}(111)/Alq{sub 3}/Co spin-valve (SV). I-V characteristics exhibit a transition in conduction mode from carrier injection to tunneling across T{sub V} of Fe{sub 3}O{sub 4} electrode. Both giant magneto-resistance (GMR) and tunneling MR (TMR) have been observed in a single SV, below and above T{sub V}, respectively. We have achieved room-temperature SV operation in our device. We believe that the tuning of charge gap at Fermi level across T{sub V} resulting in a corresponding tuning of conduction mode and a unique cross over from GMR to TMR.

  18. Evolution of Griffith's phase in La{sub 0.4}Bi{sub 0.6}Mn{sub 1?x}Ti{sub x}O{sub 3} perovskite oxide

    SciTech Connect (OSTI)

    Dayal, Vijaylakshmi Kumar, Punith V.; Hadimani, R. L.; Jiles, D. C.

    2014-05-07

    Samples of La{sub 0.4}Bi{sub 0.6}Mn{sub 1?x}Ti{sub x}O{sub 3} have been prepared and their microstructure, composition, and magnetic properties have been investigated for x?=?0.05, 0.1, and 0.5.The deviation in the inverse susceptibility behavior from Curie-Weiss law and increase in susceptibility exponent indicates the evolution of the Griffith's phase in La{sub 0.4}Bi{sub 0.6}Mn{sub 1?x}Ti{sub x}O{sub 3} around T{sub C}. The presence of Griffith's Phase is inferred due to magnetic frustration with increasing Ti concentration. The deviation between field cooled and zero field cooled magnetization curves is observed in these samples and is attributed to the appearance of the spin glass or cluster glass state that arises due to the magnetic anisotropy.

  19. Using real-time electron microscopy to explore the effects of transition-metal composition on the local thermal stability in charged Li<sub>xsub>Ni<sub>yMnzCo>1-y-zsub>O>2sub> cathode materials

    SciTech Connect (OSTI)

    Hwang, Sooyeon; Kim, Seung Min; Bak, Seong -Min; Kim, Se Young; Cho, Byung -Won; Chung, Kyung Yoon; Lee, Jeong Yong; Stach, Eric A.; Chang, Wonyoung

    2015-05-08

    In this study, we use in-situ transmission electron microcopy (TEM) to investigate the thermal decomposition that occurs at the surface of charged Li<sub>xsub>Ni<sub>yMnzCo>1-y-zsub>O>2sub> (NMC) cathode materials of different composition (with y, z=0.8, 0.1 and 0.6, 0.2 and 0.4, 0.3), after they have been charged to their practical upper limit voltage (4.3V). By heating these materials inside the TEM, we are able to directly characterize near surface changes in both their electronic structure (using electron energy loss spectroscopy) and crystal structure and morphology (using electron diffraction and bright-field imaging). The most Ni-rich material (y, z = 0.8, 0.1) is found to be thermally unstable at significantly lower temperatures than the other compositions – this is manifested by changes in both the electronic structure and the onset of phase transitions at temperatures as low as 100°C. Electron energy loss spectroscopy indicates that the thermally induced reduction of Ni ions drives these changes, and that this is exacerbated by the presence of an additional redox reaction that occurs at 4.2V in the y, z = 0.8, 0.1 material. Exploration of individual particles shows that there are substantial variations in the onset temperatures and overall extent of these changes. Of the compositions studied, the composition of y, z = 0.6, 0.2 has the optimal combination of high energy density and reasonable thermal stability. The observations herein demonstrate that real time electron microscopy provide direct insight into the changes that occur in cathode materials with temperature, allowing optimization of different alloy concentrations to maximize overall performance.

  20. Charge-Coupled Substituted Garnets (Y<sub>3-xsub>Ca>0.5xsub>M>0.5xsub>)Fe>5sub>O>12sub> (M = Ce, Th): Structure and Stability as Crystalline Nuclear Waste Forms

    SciTech Connect (OSTI)

    Guo, Xiaofeng; Kukkadapu, Ravi K.; Lanzirotti, Antonio; Newville, Matthew; Engelhard, Mark H.; Sutton, Stephen R.; Navrotsky, Alexandra

    2015-06-08

    The garnet structure has been proposed as a potential crystalline nuclear waste form for accommodation of actinide elements, especially uranium (U). In this study, yttrium iron garnet (YIG) as a model garnet host was studied for the incorporation of U analogs, cerium (Ce) and thorium (Th), incorporated by a charge-coupled substitution with calcium (Ca) for yttrium (Y) in YIG, namely, 2Y3+ = Ca2+ + M4+, where M4+ = Ce4+ or Th4+. Single-phase garnets Y<sub>3–xsub>Ca>0.5xsub>M>0.5xsub>Fe>5sub>O>12sub> (x = 0.1–0.7) were synthesized by the citrate–nitrate combustion method. Ce was confirmed to be tetravalent by X-ray absorption spectroscopy and X-ray photoelectron spectroscopy. X-ray diffraction and 57Fe–Mössbauer spectroscopy indicated that M4+ and Ca2+ cations are restricted to the c site, and the local environments of both the tetrahedral and the octahedral Fe3+ are systematically affected by the extent of substitution. The charge-coupled substitution has advantages in incorporating Ce/Th and in stabilizing the substituted phases compared to a single substitution strategy. Enthalpies of formation of garnets were obtained by high temperature oxide melt solution calorimetry, and the enthalpies of substitution of Ce and Th were determined. The thermodynamic analysis demonstrates that the substituted garnets are entropically rather than energetically stabilized. This suggests that such garnets may form and persist in repositories at high temperature but might decompose near room temperature.

  1. Cathode encapsulation of organic light emitting diodes by atomic layer deposited Al{sub 2}O{sub 3} films and Al{sub 2}O{sub 3}/a-SiN{sub x}:H stacks

    SciTech Connect (OSTI)

    Keuning, W.; Weijer, P. van de; Lifka, H.; Kessels, W. M. M.; Creatore, M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Philips Research Laboratories, High Tech Campus 4, P.O. Box WAG12, 5656 AE Eindhoven (Netherlands); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2012-01-15

    Al{sub 2}O{sub 3} thin films synthesized by plasma-enhanced atomic layer deposition (ALD) at room temperature (25 deg. C) have been tested as water vapor permeation barriers for organic light emitting diode devices. Silicon nitride films (a-SiN{sub x}:H) deposited by plasma-enhanced chemical vapor deposition served as reference and were used to develop Al{sub 2}O{sub 3}/a-SiN{sub x}:H stacks. On the basis of Ca test measurements, a very low intrinsic water vapor transmission rate of {<=} 2 x 10{sup -6} g m{sup -2} day{sup -1} and 4 x 10{sup -6} g m{sup -2} day{sup -1} (20 deg. C/50% relative humidity) were found for 20-40 nm Al{sub 2}O{sub 3} and 300 nm a-SiN{sub x}:H films, respectively. The cathode particle coverage was a factor of 4 better for the Al{sub 2}O{sub 3} films compared to the a-SiN{sub x}:H films and an average of 0.12 defects per cm{sup 2} was obtained for a stack consisting of three barrier layers (Al{sub 2}O{sub 3}/a-SiN{sub x}:H/Al{sub 2}O{sub 3}).

  2. Influence of composition modification on Ca{sub 0.5?x}Mg{sub x}Ti{sub 2}(PO{sub 4}){sub 3} (0.0 ? x ? 0.5) nanoparticles as electrodes for lithium batteries

    SciTech Connect (OSTI)

    Vidal-Abarca, C. Aragn, M.J.; Lavela, P.; Tirado, J.L.

    2014-01-01

    Graphical abstract: - Highlights: Cation mixing was determined in the Ca{sub 0.5?x}Mg{sub x}Ti{sub 2}(PO{sub 4}){sub 3} biphasic series. Nanometric Ca{sub 0.15}Mg{sub 0.35}Ti{sub 2}(PO{sub 4}){sub 3} delivered 138 mAh/g at C/20 in lithium cells. Low content of Ca{sup 2+} increases cell volume favoring Li{sup +} insertion in R-3c framework. Diminution of R{sub SEI} and R{sub CT} for Ca{sub 0.15}Mg{sub 0.35}Ti{sub 2}(PO{sub 4}){sub 3} discharged electrodes. Fast electrode response for x = 0.35. - Abstract: The Ca{sub 0.5?x}Mg{sub x}Ti{sub 2}(PO{sub 4}){sub 3} series (0.0 ? x ? 0.5) was prepared by a solgel method. X-ray diffraction patterns showed two rhombohedral phases which coexist for intermediate compositions. Despite of the absence of a solid solution mechanism for the whole stoichiometry range, an appreciable cation mixing was observed in both phases. {sup 31}P MAS NMR spectroscopy revealed that low magnesium contents are incorporated to the calcium compound inducing changes in the ordering of the alkaline earth cations in M{sub 1} sites. Derivative plots of the voltagecapacity curves revealed two reversible regions ascribed to the reduction of Ti{sup 4+} to Ti{sup 3+}, ascribable to the subsequent insertion of lithium ions into M{sub 1} and M{sub 2} vacant sites. Capacity values as high as 138 mAh/g after the first discharge were monitored for nanometric Ca{sub 0.15}Mg{sub 0.35}Ti{sub 2}(PO{sub 4}){sub 3} at C/20. Cell cycling under successive kinetic rates revealed a good capacity retention for samples with x = 0.15 and 0.25. Impedance spectra were recorded in lithium cells discharged after different number of cycles at different C rates. The increase in charge transfer resistance was shown to be an important factor determining the electrode behavior on extended cycling.

  3. Microsoft Word - IGCA Inventory Sub Guide 031611 | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    IGCA Inventory Sub Guide 031611 Microsoft Word - IGCA Inventory Sub Guide 031611 PDF icon Microsoft Word - IGCA Inventory Sub Guide 031611 More Documents & Publications IGCA ...

  4. Method of producing hydrogen. [KNO/sub 3/ and I/sub 2/

    DOE Patents [OSTI]

    Abraham, B.M.; Schreiner, F.

    1975-12-30

    Water is thermochemically decomposed to produce hydrogen by the following sequence of reactions. KNO/sub 3/ and I/sub 2/ are reacted to produce KI, NO and O/sub 2/, the NO and O/sub 2/ thus produced are reacted with water to form HNO/sub 3/, a hydrogen-containing iodide--NH/sub 4/I or HI--is formed from the HNO/sub 3/, and this iodide is thermally decomposed to produce hydrogen, all products of the reactions being recycled except hydrogen and oxygen. 2 claims, no drawings.

  5. Soft supersymmetry breaking terms from D{sub 4}xZ{sub 2} lepton flavor

    Office of Scientific and Technical Information (OSTI)

    symmetry (Journal Article) | SciTech Connect Soft supersymmetry breaking terms from D{sub 4}xZ{sub 2} lepton flavor symmetry Citation Details In-Document Search Title: Soft supersymmetry breaking terms from D{sub 4}xZ{sub 2} lepton flavor symmetry We study the supersymmetric model with D{sub 4}xZ{sub 2} lepton flavor symmetry. We evaluate soft supersymmetry breaking terms, i.e., soft slepton masses and A-terms, which are predicted in the D{sub 4} flavor model. We consider constraints due to

  6. New tetragonal derivatives of cubic NaZn{sub 13}-type structure: RNi{sub

    Office of Scientific and Technical Information (OSTI)

    6}Si{sub 6} compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd-Yb) (Journal Article) | SciTech Connect New tetragonal derivatives of cubic NaZn{sub 13}-type structure: RNi{sub 6}Si{sub 6} compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd-Yb) Citation Details In-Document Search Title: New tetragonal derivatives of cubic NaZn{sub 13}-type structure: RNi{sub 6}Si{sub 6} compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd-Yb) Novel

  7. Synthesis and crystal structure of a new open-framework iron phosphate (NH{sub 4}){sub 4}Fe{sub 3}(OH){sub 2}F{sub 2}[H{sub 3}(PO{sub 4}){sub 4}]: Novel linear trimer of corner-sharing Fe(III) octahedra

    SciTech Connect (OSTI)

    Mi, Jin-Xiao; Wang, Cheng-Xin; Chen, Ning; Li, Rong; Pan, Yuanming

    2010-12-15

    A new iron phosphate (NH{sub 4}){sub 4}Fe{sub 3}(OH){sub 2}F{sub 2}[H{sub 3}(PO{sub 4}){sub 4}] has been synthesized hydrothermall