National Library of Energy BETA

Sample records for br ush cr

  1. Performance of LiAlloy/Ag(2)CrO(4) Couples in Molten CsBr-LiBr-KBr Eutectic

    SciTech Connect (OSTI)

    GUIDOTTI,RONALD A.; REINHARDT,FREDERICK W.

    1999-10-18

    The performance of Li-alloy/CsBr-LiBr-KBr/Ag{sub 2}CrO{sub 4} systems was studied over a temperature range of 250 C to 300 C, for possible use as a power source for geothermal borehole applications. Single cells were discharged at current densities of 15.8 and 32.6 mA/cm{sup 2} using Li-Si and Li-Al anodes. When tested in 5-cell batteries, the Li-Si/CsBr-LiBr-KBr/Ag{sub 2}CrO{sub 4} system exhibited thermal runaway. Thermal analytical tests showed that the Ag{sub 2}CrO{sub 4} cathode reacted exothermically with the electrolyte on activation. Consequently, this system would not be practical for the envisioned geothermal borehole applications.

  2. br Owner br Facility br Type br Capacity br MW br Commercial...

    Open Energy Info (EERE)

    Owner br Facility br Type br Capacity br MW br Commercial br Online br Date br Geothermal br Area br Geothermal br Region Coordinates Ahuachapan Geothermal Power Plant LaGeo SA de...

  3. High field magnetotransport and point contact Andreev reflection measurements on CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}BrDegenerate magnetic semiconductor single crystals

    SciTech Connect (OSTI)

    Borisov, K. Coey, J. M. D.; Stamenov, P.; Alaria, J.

    2014-05-07

    Single crystals of the metallically degenerate fully magnetic semiconductors CuCr{sub 2}Se{sub 4} and CuCr{sub 2}Se{sub 3}Br have been prepared by the Chemical Vapour Transport method, using either Se or Br as transport agents. The high-quality, millimetre-sized, octahedrally faceted, needle- and platelet-shaped crystals are characterised by means of high field magnetotransport (?{sub 0}H? 14?T) and Point Contact Andreev Reflection. The relatively high spin polarisation observed |P|>0.56, together with the relatively low minority carrier effective mass of 0.25 m{sub e}, and long scattering time 10{sup ?13}?s, could poise these materials for integration in low- and close-to-room temperature minority injection bipolar heterojunction transistor demonstrations.

  4. Jatropha BR | Open Energy Information

    Open Energy Info (EERE)

    BR Jump to: navigation, search Name: Jatropha BR Place: Brazil Product: Brazilian-based consortium of five leading Brazilian companies engaged in the integrated jatropha curcas...

  5. Photoelectron Emission Studies in CsBr at 257 nm

    SciTech Connect (OSTI)

    Maldonado, Juan R.; Liu, Zhi; Sun, Yun; Pianetta, Piero A.; Pease, Fabian W.; /Stanford U., Elect. Eng. Dept. /SLAC, SSRL

    2006-09-28

    CsBr/Cr photocathodes were found [1,2] to meet the requirements of a multi-electron beam lithography system operating with a light energy of 4.8 eV (257nm). The fact that photoemission was observed with a light energy below the reported 7.3 eV band gap for CsBr was not understood. This paper presents experimental results on the presence of intra-band gap absorption sites (IBAS) in CsBr thin film photo electron emitters, and presents a model based on IBAS to explain the observed photoelectron emission behavior at energies below band gap. A fluorescence band centered at 330 nm with a FWHM of about 0.34 eV was observed in CsBr/Cr samples under 257 nm laser illumination which can be attributed to IBAS and agrees well with previously obtained synchrotron photoelectron spectra[1] from the valence band of CsBr films.

  6. Characterization of high-voltage cathodes in CsBr-LiBr-KBr eutectic electrolyte

    SciTech Connect (OSTI)

    GUIDOTTI,RONALD A.; REINHARDT,FREDERICK W.

    2000-04-20

    The transition-metal oxides LiMn{sub 2}O{sub 4}, MnO{sub 2}, CrO{sub 2}, and LiCoO{sub 2} were evaluated for possible use as high-voltage cathodes for potential geothermal power applications. These were coupled with Li(Si) anodes and a low-melting CsBr-LiBr-KBr eutectic electrolyte that melts at 228.5 C. Single-cell tests at 250 C and 300 C at 15.8 and 31.6 mA/cm{sup 2} showed that MnO{sub 2} performed the best overall and had the lowest polarization. A 5-cell battery test using LiMn{sub 2}O{sub 4} cathodes was only modestly successful due to possible parasitic chemical reactions between the cathode and electrolyte at the much higher temperature (500 C) during discharge. The overall energy densities for these cathode were still less than for FeS{sub 2}.

  7. Photoinduced Br Desorption from CsBr Thin Films Grown on Cu(100)

    SciTech Connect (OSTI)

    Halliday, Matthew T.; Joly, Alan G.; Hess, Wayne P.; Shluger, AL

    2015-10-22

    Thin films of CsBr deposited onto metals such as copper are potential photocathode materials for light sources and other applications. We investigate desorption dynamics of Br atoms from CsBr films grown on insulator (KBr, LiF) and metal (Cu) substrates induced by sub-bandgap 6.4 eV laser pulses. The experimental results demonstrate that the peak kinetic energy of Br atoms desorbed from CsBr/Cu films is much lower than that for the hyperthermal desorption from CsBr/LiF films. Kelvin probe measurements indicate negative charge at the surface following Br desorption from CsBr/Cu films. Our ab initio calculations of excitons at CsBr surfaces demonstrate that this behavior can be explained by an exciton model of desorption including electron trapping at the CsBr surface. Trapped negative charges reduce the energy of surface excitons available for Br desorption. We examine the electron-trapping characteristics of low-coordinated sites at the surface, in particular, divacancies and kink sites. We also provide a model of cation desorption caused by Franck-Hertz excitation of F centers at the surface in the course of irradiation of CsBr/Cu films. These results provide new insights into the mechanisms of photoinduced structural evolution of alkali halide films on metal substrates and activation of metal photocathodes coated with CsBr.

  8. Photochemistry of Methyl Bromide on the α-Cr2O3(0001) Surface

    SciTech Connect (OSTI)

    Henderson, Michael A.

    2010-09-30

    The photochemical properties of the Cr-terminated α-Cr2O3(0001) surface were explored using methyl bromide (CH3Br) as a probe molecule. CH3Br adsorbed and desorbed molecularly from the Cr-terminated α-Cr2O3(0001) surface without detectable thermal decomposition. Temperature programmed desorption (TPD) revealed a CH3Br desorption state at 240 K for coverages up to 0.5 ML, followed by more weakly bound molecules desorbing at 175 K for coverages up to 1 ML. Multilayer exposures led to desorption at ~130 K. The CH3Br sticking coefficient was unity at 105 K for coverages up to monolayer saturation, but decreased as the multilayer formed. In contrast, pre-oxidation of the surface (using an oxygen plasma source) led to capping of surface Cr3+ sites and near complete removal of CH3Br TPD states above 150 K. The photochemistry of chemisorbed CH3Br was explored on the Cr-terminated surface using post-irradiation TPD and photon stimulated desorption (PSD). Irradiation of adsorbed CH3Br with broad band light from a Hg arc lamp resulted in both photodesorption and photodecomposition of the parent molecule at a combined cross section of ~10-22 cm2. Parent PSD was indicative of molecular photodesorption, but CH3 was also detected in PSD and Br atoms were left on the surface, both reflective of photo-induced CH3-Br bond dissociation. Use of a 385 nm cut-off filter effectively shut down the photodissociation pathway but not the parent molecule photodesorption process. From these observations it is inferred that d-to-d transitions in α-Cr2O3, occurring at photon energies <3 eV, are not responsible for photodecomposition of 2 adsorbed CH3Br. It is unclear to what extent band-to-band versus direct CH3Br photolysis play in CH3-Br bond dissociation initiated by more energetic photons.

  9. X-ray absorption studies of mixed salt polymer electrolytes: ZnBr{sub 2}/CaBr{sub 2}-PEO, ZnBr{sub 2}/LiBr-PEO, and ZnBr{sub 2}/RbBr-PEO complexes

    SciTech Connect (OSTI)

    McBreen, J.; Yang, X.Q.; Lee, H.S.; Okamoto, Y.

    1995-02-01

    Polyethylene oxide (PEO)-salt systems are an important new class of electrolytes that are being considered for many uses. X-ray absorption (XAS) studies of ZnBr{sub 2}-PEO complexes, at the Zn K edge, at temperatures between 25 and 120 C, indicate that additions of bromide salts of Li, Rb, or Ca result in the formation of ZnBr{sub 4}{sup {minus} 2} complexes with a Zn-Br bond length of 2.42 {angstrom}. XAS, at the Rb K edge, in mixed RbBr/ZnBr{sub 2}-PEO complexes with an excess of ZnBr{sub 2}, shows that the ZnBr{sub 2} causes the RbBr to dissolve in the polymer. The Rb{sup +} ions are weakly complexed with the PEO with an Rb-O bond distance of 2.93 {angstrom}.

  10. Materials Data on CrBrO (SG:59) by Materials Project

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  11. High energy XeBr electric discharge laser

    DOE Patents [OSTI]

    Sze, Robert C.; Scott, Peter B.

    1981-01-01

    A high energy XeBr laser for producing coherent radiation at 282 nm. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr is used as the halogen donor which undergoes harpooning reactions with Xe.sub.M * to form XeBr*.

  12. High energy XeBr electric discharge laser

    DOE Patents [OSTI]

    Sze, R.C.; Scott, P.B.

    A high energy XeBr laser for producing coherent radiation at 282 nm is disclosed. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr, is used as the halogen donor which undergoes harpooning reactions with Xe/sub M/ to form XeBr.

  13. GLADY CASSIT Y VANDALIA MURPHY CR EEK BU CKHN-CENT URY CLAY

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

    GLADY CASSIT Y VANDALIA MURPHY CR EEK BU CKHN-CENT URY CLAY GLENVILLE N MINNORA JARVISVILLE FAR MINGTON PH ILIPPI BELIN GT ON WAYN ESBUR G PR UNT Y GLENVILLE S CAVE RUN TAYLOR DRAIN ROSEDALE ST MPT-N RMNT-SHK WESTON-JAN E LEW SWN DL-WID EN VADIS STANL EY DEKALB UNION TALLM AN SVILL E ASPINALL-FIN ST ER ZOLLARSVILLE WILBU R RAMSEY HEATER S BR IDGEPORT-PRUNT YTOWN ALEXAND ER LILLY FORK SH ERMAN HIRAM ST FK-BLST N CK BU RNS CH APEL S BR WN -LUM BER PORT CON INGS PR ATT BOSWELL REVEL ELK C REEK

  14. Improved production of Br atoms near zero speed by photodissociating laser aligned Br{sub 2} molecules

    SciTech Connect (OSTI)

    Deng, L. Z., E-mail: lzdeng@phy.ecnu.edu.cn; Yin, J. P., E-mail: jpyin@phy.ecnu.edu.cn [State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062 (China)

    2014-10-28

    We theoretically investigated the improvement on the production rate of the decelerated bromine (Br) atoms near zero speed by photodissociating laser aligned Br{sub 2} precursors. Adiabatic alignment of Br{sub 2} precursors exposed to long laser pulses with duration on the order of nanoseconds was investigated by solving the time-dependent Schrdinger equation. The dynamical fragmentation of adiabatically aligned Br{sub 2} precursors was simulated and velocity distribution of the Br atoms produced was analyzed. Our study shows that the larger the degree of the precursor alignment, ?cos{sup 2}???, the higher the production rate of the decelerated Br atoms near zero speed. For Br{sub 2} molecules with an initial rotational temperature of ?1 K, a ?cos{sup 2}??? value of ?0.88 can result in an improvement factor of over ?20 on the production rate of the decelerated Br atoms near zero speed, requiring a laser intensity of only ?1 10{sup 12} W/cm{sup 2} for alignment.

  15. Preliminary upper limit on BR(D{sup {+-}}{r_arrow}{pi}{sup {...

    Office of Scientific and Technical Information (OSTI)

    Preliminary upper limit on BR(Dsup +-rarrowpisup +-musup +musup -) Citation Details In-Document Search Title: Preliminary upper limit on BR(Dsup ...

  16. Ca2+-Doped CeBr3 Scintillating Materials

    SciTech Connect (OSTI)

    Guss, Paul; Foster, Michael E.; Wong, Bryan M.; Doty, F. Patrick; Shah, Kanai; Squillante, Michael R.; Shirwadkar, Urmila; Hawrami, Rastgo; Tower, Josh; Yuan, Ding

    2014-01-21

    Despite the outstanding scintillation performance characteristics of cerium tribromide (CeBr3) and cerium-activated lanthanum tribromide, their commercial availability and application are limited due to the difficulties of growing large, crack-free single crystals from these fragile materials. This investigation employed aliovalent doping to increase crystal strength while maintaining the optical properties of the crystal. One divalent dopant (Ca2+) was used as a dopant to strengthen CeBr3 without negatively impacting scintillation performance. Ingots containing nominal concentrations of 1.9% of the Ca2+ dopant were grown. Preliminary scintillation measurements are presented for this aliovalently doped scintillator. Ca2+-doped CeBr3 exhibited little or no change in the peak fluorescence emission for 371 nm optical excitation for CeBr3. The structural, electronic, and optical properties of CeBr3 crystals were studied using the density functional theory within the generalized gradient approximation. The calculated lattice parameters are in good agreement with the experimental data. The energy band structures and density of states were obtained. The optical properties of CeBr3, including the dielectric function, were calculated.

  17. Decommissioning of the BR3 reactor: status and perspectives

    SciTech Connect (OSTI)

    Noynaert, L.; Verstraeten, I.

    2007-07-01

    The BR3 plant at Mol in Belgium built at the end of the fifties was the first PWR plant built outside the USA. The reactor had a small net power output (10 MWe) but comprised all the loops and features of a commercial PWR plant. The BR3 plant was operated with the main objective of testing advanced PWR fuels under irradiation conditions similar to those encountered in large commercial PWR plants. The reactor was started in 1962 and shut down in 1987 after 25 years of continuous operation. Since 1989, SCK.CEN is decommissioning the BR3 PWR research reactor. The dismantling of the metallic components including reactor pressure vessel and internals is completed and extensively reported in the literature. The dismantling of auxiliary components and the decontamination of parts of the infrastructure are now going on. The decommissioning progress is continuously monitored and costs and strategy are regularly reassessed. The first part of the paper describes the main results and lessons learned from the reassessment exercises performed in 1994, 1999, 2004 and 2007. Impacts of changes in legal framework on the decommissioning costs will be addressed. These changes concern e.g. licensing aspects, clearance levels, waste management... The middle part of the paper discusses the management of activated and/or contaminated concrete. The costing exercise performed in 1995 highlighted that the management of activated and contaminated concrete is the second main cost item after the dismantling of the reactor pressure vessel and internals. Different possible solutions were studied. These are evacuation as radioactive waste with or without supercompaction, recycling this 'radioactive' grout or concrete for conditioning of radioactive waste e.g. conditioning of metallic waste. The paper will give the results of the cost-benefit analysis made to select the solution retained. The last part of the paper will discuss the end goal of the decommissioning of the BR3. In the final

  18. A preliminary report on the photoionization efficiency spectrum, ionization energy and heat of formation of Br{sub 2}O; and the appearance energy of BrO{sup +} (Br{sub 2}O)

    SciTech Connect (OSTI)

    Thorn, R.P. Jr.; Monks, P.S.; Stief, L.J.; Kuo, S.C.; Zhang, Z.; Klemm, R.B.

    1995-08-01

    We report experimental results for the photoionization efficiency (PIE) spectrum of Br{sub 2}O along with the ionization energy (derived form the ionization threshold) and the appearance energy (AE) of BrO{sup +} (Br{sub 2}O). A value for the heat of formation of Br{sub 2}O is derived form the AE result. Experiments were performed by employing a discharge flow-photoionization mass spectrometer (DF-PIMS) apparatus coupled to beamline U-11 at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory.

  19. AmeriFlux BR-Sa3 Santarem-Km83-Logged Forest

    SciTech Connect (OSTI)

    Goulden, Mike

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site BR-Sa3 Santarem-Km83-Logged Forest. Site Description - Cleared forest. Logged site is near km 83 along BR-183.

  20. Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption...

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

    Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption for CHP Applications, April 2005 Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption for CHP...

  1. High gradient rf gun studies of CsBr photocathodes

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

    Vecchione, Theodore; Maldonado, Juan R.; Gierman, Stephen; Corbett, Jeff; Hartmann, Nick; Pianetta, Piero A.; Hesselink, Lambertus; Schmerge, John F.

    2015-04-03

    CsBr photocathodes have 10 times higher quantum efficiency with only 3 times larger intrinsic transverse emittance than copper. They are robust and can withstand 80 MV/m fields without breaking down or emitting dark current. They can operate in 2×10⁻⁹ torr vacuum and survive exposure to air. They are well suited for generating high pulse charge in rf guns without a photocathode transfer system.

  2. High gradient rf gun studies of CsBr photocathodes

    SciTech Connect (OSTI)

    Vecchione, Theodore; Maldonado, Juan R.; Gierman, Stephen; Corbett, Jeff; Hartmann, Nick; Pianetta, Piero A.; Hesselink, Lambertus; Schmerge, John F.

    2015-04-03

    CsBr photocathodes have 10 times higher quantum efficiency with only 3 times larger intrinsic transverse emittance than copper. They are robust and can withstand 80 MV/m fields without breaking down or emitting dark current. They can operate in 210?? torr vacuum and survive exposure to air. They are well suited for generating high pulse charge in rf guns without a photocathode transfer system.

  3. Improved Growth Methods for LaBr3 Scintillation Radiation Detectors

    SciTech Connect (OSTI)

    McGregor, Douglas S

    2011-05-01

    The objective is to develop advanced materials for deployment as high-resolution gamma ray detectors. Both LaBr3 and CeBr3 are advanced scintillation materials, and will be studied in this research. Prototype devices, in collaboration Sandia National Laboratories, will be demonstrated along with recommendations for mass production and deployment. It is anticipated that improved methods of crystal growth will yield larger single crystals of LaBr3 for deployable room-temperature operated gamma radiation spectrometers. The growth methods will be characterized. The LaBr3 and CeBr3 scintillation crystals will be characterized for light yield, spectral resolution, and for hardness.

  4. Natural Organobromine in Marine Sediments: New Evidence of Biogeochemical Br Cycling

    SciTech Connect (OSTI)

    A Leri; J Hakala; M Marcus; A Lanzirotti; C Reddy; S Myneni

    2011-12-31

    Organobromine (Br{sub org}) compounds, commonly recognized as persistent, toxic anthropogenic pollutants, are also produced naturally in terrestrial and marine systems. Several enzymatic and abiotic bromination mechanisms have been identified, as well as an array of natural Br{sub org} molecules associated with various marine organisms. The fate of the carbon-bromine functionality in the marine environment, however, remains largely unexplored. Oceanographic studies have noted an association between bromine (Br) and organic carbon (C{sub org}) in marine sediments. Even so, there has been no direct chemical evidence that Br in the sediments exists in a stable form apart from inorganic bromide (Br{sub inorg}), which is widely presumed conservative in marine systems. To investigate the scope of natural Br{sub org} production and its fate in the environment, we probed Br distribution and speciation in estuarine and marine sediments using in situ X-ray spectroscopy and spectromicroscopy. We show that Br{sub org} is ubiquitous throughout diverse sedimentary environments, occurring in correlation with C{sub org} and metals such as Fe, Ca, and Zn. Analysis of sinking particulate carbon from the seawater column links the Br{sub org} observed in sediments to biologically produced Br{sub org} compounds that persist through humification of natural organic matter (NOM). Br speciation varies with sediment depth, revealing biogeochemical cycling of Br between organic and inorganic forms as part of the burial and degradation of NOM. These findings illuminate the chemistry behind the association of Br with Corg in marine sediments and cast doubt on the paradigmatic classification of Br as a conservative element in seawater systems.

  5. Novel visible-light AgBr/Ag?PO? hybrids photocatalysts with surface plasma resonance effects

    SciTech Connect (OSTI)

    Wang, Yunfang Li, Xiuli; Wang, Yawen; Fan, Caimei

    2013-06-01

    Three kinds of AgBr/Ag?PO? hybrids were synthesised via an anion-exchange precipitation method and characterised by XRD, XPS, SEM, EDS, and UVvis. The results showed that AgBr/Ag?PO? hybrids displayed much higher photocatalytic activities than single Ag?PO? or AgBr under visible light (?>420 nm), and OH and h? were the major active species during the degradation process. Considering interstitial ions Ag?? on lattice gap of AgBr are easy to become sliver particle, we deduced the possible photocatalytic mechanism could be ascribed to the synergistic effects of the appropriate valence band position of Ag?PO? and AgBr, surface plasmon resonance effect of Ag?, reactive radical species Br?, and the Ag vacancy on the surface of catalysts. - Graphical abstract: The optical absorption and structural morphology of the as-prepared AgBr@Ag?PO? photocatalyst using an anion-exchange precipitation method are conductive to the photocatalytic degradation of organics in water. Highlights: Novel AgBr/Ag?PO? hybrids are synthesised by a facile method. AgBr/Ag?PO? hybrids show excellent photocatalytic activities under visible light. Interstitial ions are in favour of the formation of Ag particle. Surface plasmon resonance effect plays a key factor for light absorption. The photocatalytic mechanism for AgBr/Ag?PO? hybrids is studied.

  6. Process for depositing Cr-bearing layer

    DOE Patents [OSTI]

    Ellis, T.W.; Lograsso, T.A.; Eshelman, M.A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate. 7 figs.

  7. Process for depositing Cr-bearing layer

    DOE Patents [OSTI]

    Ellis, Timothy W.; Lograsso, Thomas A.; Eshelman, Mark A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate.

  8. X-ray photoemission analysis of chemically modified TlBr surfaces for improved radiation detectors

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

    Nelson, A. J.; Voss, L. F.; Beck, P. R.; Graff, R. T.; Conway, A. M.; Nikolic, R. J.; Payne, S. A.; Lee, J. -S.; Kim, H.; Cirignano, L.; et al

    2013-01-12

    We subjected device-grade TlBr to various chemical treatments used in room temperature radiation detector fabrication to determine the resulting surface composition and electronic structure. As-polished TlBr was treated separately with HCl, SOCl2, Br:MeOH and HF solutions. High-resolution photoemission measurements on the valence band electronic structure and Tl 4f, Br 3d, Cl 2p and S 2p core lines were used to evaluate surface chemistry and shallow heterojunction formation. Surface chemistry and valence band electronic structure were correlated with the goal of optimizing the long-term stability and radiation response.

  9. Apparatus for improving the working time of the XeBr laser

    DOE Patents [OSTI]

    Sander, Robert K.; Balog, George; Seegmiller, Emma T.

    1982-01-01

    In XeBr lasers which make use of HBr as the source of bromine, it has been found that the working life of the laser is limited because of dissociation of the HBr in the lasing region to form H.sub.2 and Br.sub.2. Accordingly, apparatus is disclosed for substantially improving the working time of the XeBr laser wherein means are provided for recombining H.sub.2 and Br.sub.2 into HBr and for continuously circulating the gaseous working medium from the lasing region through the recombination region. BACKGROUND OF THE INVENTION

  10. Apparatus for improving the working time of the XeBr laser

    DOE Patents [OSTI]

    Sander, R.K.; Balog, G.; Seegmiller, E.T.

    1980-03-04

    In XeBr lasers which make use of HBr as the source of bromine, it has been found that the working life of the laser is limited because of dissociation of the HBr in the lasing region to form H/sub 2/ and Br/sub 2/. Accordingly, apparatus is disclosed for substantially improving the working time of the XeBr laser wherein means are provided for recombining H/sub 2/ and Br/sub 2/ into HBr and for continuously circulating the gaseous working medium from the lasing region through the recombination region.

  11. Nucleation of Cr precipitates in Fe-Cr alloy under irradiation

    SciTech Connect (OSTI)

    Dai, Y. Y.; Ao, L.; Sun, Qing- Qiang; Yang, L.; Nie, JL; Peng, SM; Long, XG; Zhou, X. S.; Zu, Xiaotao; Liu, L.; Sun, Xin; Terentyev, Dimtry; Gao, Fei

    2015-04-01

    The nucleation of Cr precipitates induced by overlapping of displacement cascades in Fe-Cr alloys has been investigated using the combination of molecular dynamics (MD) and Metropolis Monte Carlo (MMC) simulations. The results reveal that the number of Frenkel pairs increases with the increasing of overlapped cascades. Overlapping cascades could promote the formation of Cr precipitates in Fe-Cr alloys, as analyzed using short range order (SRO) parameters to quantify the degree of ordering and clustering of Cr atoms. In addition, the simulations using MMC approach show that the presence of small Cr clusters and vacancy clusters formed within cascade overlapped region enhance the nucleation of Cr precipitates, leading to the formation of large Cr dilute precipitates.

  12. Nanoscale Phase Separation In Epitaxial Cr-Mo and Cr-V Alloy...

    Office of Scientific and Technical Information (OSTI)

    In Epitaxial Cr-Mo and Cr-V Alloy Thin Films Studied Using Atom Probe Tomography. ... Therefor laser assisted atom probe tomography (APT) was utilized to study the phase ...

  13. Microsoft Word - CR.doc

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

    March 2004 Table 1. Estimated composition of REDOX HLW released from Tank 108 to the vadose zone in 1969 (from Jones et al., 2000). Temperature (° C) 100 H 2 O mole fraction 0.539 H 2 O weight fraction 0.304 Solution density (g/cm 3 ) 2.09 Ionic strength 18.02 Primary Chemical Species (mol/L) Al(OH) 4 - 3.36 K + 7.39 x 10 -2 Na + 19.6 OH - 5.25 NO 3 - 5.46 NO 2 - 4.42 Cl - 0.34 CO 3 2- 3.25 x 10 -2 SO 4 2- 2.77 x 10 -2 CrO 4 2- 4.13 x 10 -1 137 Cs + 6.51 x 10 -5 Table 1. Estimated composition

  14. Results for aliovalent doping of CeBr{sub 3} with Ca{sup 2+}

    SciTech Connect (OSTI)

    Guss, Paul; Foster, Michael E.; Wong, Bryan M.; Patrick Doty, F.; Shah, Kanai; Squillante, Michael R.; Shirwadkar, Urmila; Hawrami, Rastgo; Tower, Joshua; Yuan, Ding

    2014-01-21

    Despite the outstanding scintillation performance characteristics of cerium tribromide (CeBr{sub 3}) and cerium-activated lanthanum tribromide, their commercial availability and application are limited due to the difficulties of growing large, crack-free single crystals from these fragile materials. This investigation employed aliovalent doping to increase crystal strength while maintaining the optical properties of the crystal. One divalent dopant (Ca{sup 2+}) was used as a dopant to strengthen CeBr{sub 3} without negatively impacting scintillation performance. Ingots containing nominal concentrations of 1.9% of the Ca{sup 2+} dopant were grown, i.e., 1.9% of the CeBr{sub 3} molecules were replaced by CaBr{sub 2} molecules, to match our target replacement of 1 out of 54 cerium atoms be replaced by a calcium atom. Precisely the mixture was composed of 2.26 g of CaBr{sub 2} added to 222.14 g of CeBr{sub 3}. Preliminary scintillation measurements are presented for this aliovalently doped scintillator. Ca{sup 2+}-doped CeBr{sub 3} exhibited little or no change in the peak fluorescence emission for 371?nm optical excitation for CeBr{sub 3}. The structural, electronic, and optical properties of CeBr{sub 3} crystals were studied using the density functional theory within the generalized gradient approximation. Calculated lattice parameters are in agreement with the experimental data. The energy band structures and density of states were obtained. The optical properties of CeBr{sub 3}, including the dielectric function, were calculated.

  15. Structural analysis of Cr aggregation in ferromagnetic semiconductor (Zn,Cr)Te

    SciTech Connect (OSTI)

    Kobayashi, H.; Yamawaki, K.; Nishio, Y.; Kanazawa, K.; Kuroda, S.; Mitome, M.; Bando, Y.

    2013-12-04

    The Cr aggregation in a ferromagnetic semiconductor (Zn,Cr)Te was studied by performing precise analyses using TEM and XRD of microscopic structure of the Cr-aggregated regions formed in iodine-doped Zn{sub 1?x}Cr{sub x}Te films with a relatively high Cr composition x ? 0.2. It was found that the Cr-aggregated regions are composed of Cr{sub 1??}Te nanocrystals of the hexagonal structure and these hexagonal precipitates are stacked preferentially on the (111)A plane of the zinc-blende (ZB) structure of the host ZnTe crystal with its c-axis nearly parallel to the (111){sub ZB} plane.

  16. Interstitial loop transformations in FeCr

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

    Béland, Laurent Karim; Osetsky, Yuri N.; Stoller, Roger E.; Xu, Haixuan

    2015-03-27

    Here, we improve the Self-Evolving Atomistic Kinetic Monte Carlo (SEAKMC) algorithm by integrating the Activation Relaxation Technique nouveau (ARTn), a powerful open-ended saddle-point search method, into the algorithm. We use it to investigate the reaction of 37-interstitial 1/2[1 1 1] and 1/2[View the MathML source] loops in FeCr at 10 at.% Cr. They transform into 1/2[1 1 1], 1/2[View the MathML source], [1 0 0] and [0 1 0] 74-interstitial clusters with an overall barrier of 0.85 eV. We find that Cr decoration locally inhibits the rotation of crowdions, which dictates the final loop orientation. Moreover, the final loop orientationmore » depends on the details of the Cr decoration. Generally, a region of a given orientation is favored if Cr near its interface with a region of another orientation is able to inhibit reorientation at this interface more than the Cr present at the other interfaces. Also, we find that substitutional Cr atoms can diffuse from energetically unfavorable to energetically favorable sites within the interlocked 37-interstitial loops conformation with barriers of less than 0.35 eV.« less

  17. Characterization of the LiSi/CsBr-LiBr-KBr/FeS(2) System for Potential Use as a Geothermal Borehole Power Source

    SciTech Connect (OSTI)

    GUIDOTTI, RONALD A.; REINHARDT, FREDERICK W.

    1999-10-18

    We are continuing to study the suitability of modified thermal-battery technology as a potential power source for geothermal borehole applications. Previous work focused on the LiSi/FeS{sub 2} couple over a temperature range of 350 C to 400 C with the LiBr-KBr-LiF eutectic, which melts at 324.5 C. In this work, the discharge processes that take place in LiSi/CsBr-LiBr-KBr eutectic/FeS{sub 2} thermal cells were studied at temperatures between 250 C and 400 C using pelletized cells with immobilized electrolyte. The CsBr-LiBr-KBr eutectic was selected because of its lower melting point (228.5 C). Incorporation of a quasi-reference electrode allowed the determination of the relative contribution of each electrode to the overall cell polarization. The results of single-cell tests and limited battery tests are presented, along with preliminary data for battery stacks tested in a simulated geothermal borehole environment.

  18. Studies on Ca2+-Doped CeBr3 Scintillating Materials

    SciTech Connect (OSTI)

    Guss, P. [NSTec; Foster, M. E. [SNL; Wong, B. M. [SNL; Doty, F. P. [SNL; Shah, K. [RMD; Squillante, M. [RMD; Glodo, J. [RMD; Yuan, D. [NSTec

    2013-07-03

    Despite the outstanding scintillation performance characteristics of cerium tribromide (CeBr3) and cerium-activated lanthanum tribromide (LaBr3:Ce), their commercial availability and application is limited due to the difficulties of growing large, crack-free single crystals from these fragile materials. The objective of this investigation was to employ aliovalent doping to increase crystal strength while maintaining the optical properties of the crystal. One divalent dopant (Ca2+) was investigated as a dopant to strengthen CeBr3 without negatively impacting scintillation performance. Ingots containing nominal concentrations of 1.9% of the Ca2+ dopant were grown. Preliminary scintillation measurements are presented for this aliovalently doped scintillator. Ca2+-doped CeBr3 exhibited little or no change in the peak fluorescence emission for 371 nm optical excitation for CeBr3. The structural, electronic, and optical properties of CeBr3 crystals were investigated using the density functional theory within generalized gradient approximation. The calculated lattice parameters are in good agreement with the experimental data. The energy band structures and density of states were obtained. The optical properties of CeBr3, including the dielectric function, were calculated.

  19. Structure and properties of electronic and hole centers in CsBr from theoretical calculations

    SciTech Connect (OSTI)

    Halliday, Matthew T.; Hess, Wayne P.; Shluger, Alexander L.

    2015-06-24

    The electronic structure, geometry, diffusion barriers and optical properties of fundamental defects of CsBr are calculated using hybrid functional DFT and TD- DFT methods. The B3LYP functional with a modified exchange contribution has been used in an embedded cluster scheme to model the structure and spectroscopic properties of self-trapped triplet exciton, interstitial Br atoms and ions, self-trapped holes and Br vacancies. The calculated migration barriers and positions of maxima of optical absorption bands are in good agreement with experiment, justifying the obtained defect geometries. The o*-center triplet exciton luminescence energy is also accurately calculated.

  20. Midea: ENERGY STAR Referral (MWF-08CR)

    Broader source: Energy.gov [DOE]

    DOE referred the matter of Westpointe-brand room air conditioner model MWF-08CR to the EPA for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification.

  1. NUREG/CR-6150 EGG-2720

    Office of Scientific and Technical Information (OSTI)

    ... damaged TMI-2 core.62 The experiments in Germany and Japan have revealed the existence of ... revealed by out-of pile experiments in Germany 54,55959 and 4-57 IViJREiGlCR-6150 Fuel ...

  2. Emerson: ENERGY STAR Referral (CR289E)

    Broader source: Energy.gov [DOE]

    DOE referred the matter of Emerson-brand refrigerator, model CR289E, to the EPA for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification.

  3. Measurement of the Ratio of Branching Fractions Br(Bs -> Ds- pi+)/Br(B -> D- pi+) at CDF-II

    SciTech Connect (OSTI)

    Furic, Ivan Kresimir; /MIT

    2004-03-01

    The measurement of B{sub s}{sup 0} mixing is one of the flagship analyses for the Run II B physics program. The sensitivity of the measurement to the frequency of B{sub s}{sup 0} oscillations strongly depends on the number of reconstructed B{sub s}{sup 0} mesons. They present the measurement of the ratio of branching fractions Br(B{sub s}{sup 0} {yields} D{sub s}{sup -}{pi}{sup +})/Br(B{sup 0} {yields} D{sup -}{pi}{sup +}), which directly influences the number of B{sub s}{sup 0} events available for the measurement of B{sub s}{sup 0} mixing at CDF-II. They analyze 115 pb{sup -1} of data collected with the CDF-II detector in p{bar p} collisions at {radical}s = 1.96 TeV using a novel displaced track trigger. They reconstruct 78 {+-} 11 B{sub s}{sup 0} {yields} D{sub s}{sup -}{pi}{sup +} decays at 1153 {+-} 45 B{sup 0} {yields} D{sup -}{pi}{sup +} decays with good signal to background ratio. This is the world's largest sample of fully reconstructed B{sub s}{sup 0} {yields} D{sub s}{sup -}{pi}{sup +} decays. They find the ratio of production fractions multiplied by the ratio of branching fractions to be: f{sub s}/f{sub d} {center_dot} Br(B{sub s}{sup 0} {yields} D{sub s}{sup -}{pi}{sup +})/Br(B{sup 0} {yields} D{sup -}{pi}{sup +}) = 0.325 {+-} 0.046(stat) {+-} 0.034(syst) {+-} 0.084 (BR). Using the world average value of f{sub s}/f{sub d} = 0.26 {+-} 0.03, we infer that the ratio of branching fractions is: Br(B{sub s}{sup 0} {yields} D{sub s}{sup -}{pi}{sup +})/Br(B{sup 0} {yields} D{sup -}{pi}{sup +}) = 1.25 {+-} 0.18(stat) {+-} 0.13(syst) {+-} 0.32(BR) {+-} 0.14(PR) where the last uncertainty is due to the uncertainty on the world average measurement of the ratio of B{sub s}{sup 0} to B{sup 0} production rates, f{sub s}/f{sub d}.

  4. Oxidation/Reduction Reactions at the Metal Contact-TlBr Interface...

    Office of Scientific and Technical Information (OSTI)

    Title: OxidationReduction Reactions at the Metal Contact-TlBr Interface: An X-ray Photoelectron Spectroscopy Study Authors: Nelson, A J ; Swanberg, E L ; Voss, L F ; Graff, R T ; ...

  5. LAKESHORE AVON BR ANT-EDEN ALD EN-LANC ASTER AU BURN W SH ELDON

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

    81 81 LAKESHORE AVON BR ANT-EDEN ALD EN-LANC ASTER AU BURN W SH ELDON CALEDONIA HURON C REEK LEIC EST ER COL DEN ASH FORD INDIAN FALLS LAWTONS SAR DINIA RPD-037 -2 ...

  6. Hydrogen for X-group exchange in CH3X, X = Cl, Br, I, OMe and...

    Office of Scientific and Technical Information (OSTI)

    Hydrogen for X-group exchange in CH3X, X Cl, Br, I, OMe and NMe2 byMonomeric ... Citation Details In-Document Search Title: Hydrogen for X-group exchange in CH3X, X Cl, ...

  7. Measurement of BR(Bu to phi K)/BR(Bu to J/psi K) at the collider detector at Fermilab

    SciTech Connect (OSTI)

    Napora, Robert A

    2004-10-01

    This thesis presents evidence for the decay mode B{sup {+-}} {yields} {phi}K{sup {+-}} in p{bar p} collisions at {radical}s = 1.96 TeV using (120 {+-} 7)pb{sup -1} of data collected by the Collider Detector at Fermilab (CDF). This signal is then used to measure the branching ratio relative to the decay mode B{sup {+-}} {yields} J/{psi}K{sup {+-}}. The measurement starts from reconstructing the two decay modes: B{sup {+-}} {yields} {phi}K{sup {+-}}, where {phi} {yields} K{sup +}K{sup -} and B{sup {+-}} {yields} J/{psi}K{sup {+-}}, where J/{psi} {yields} {mu}{sup +}{mu}{sup -}. The measurement yielded 23 {+-} 7 B{sup {+-}} {yields} {phi}K{sup {+-}} events, and 406 {+-} 26 B{sup {+-}} {yields} J/{psi}K{sup {+-}} events. The fraction of B{sup {+-}} {yields} J/{psi}K{sup {+-}} events where the J/{psi} subsequently decayed to two muons (as opposed to two electrons) was found to be f{sub {mu}{mu}} = 0.839 {+-} 0.066. The relative branching ratio of the two decays is then calculated based on the equation: BR(B{sup {+-}} {yields} {phi}K{sup {+-}})/BR(B{sup {+-}} {yields} J/{psi}K{sup {+-}}) = N{sub {phi}K}/N{sub {psi}K} {center_dot}f{sub {mu}{mu}} BR(J/{psi} {yields} {mu}{sup +}{mu}{sup -})/BR({phi} {yields} K{sup +}K{sup -}) {epsilon}{sub {mu}{mu}}K/{epsilon}KKK R({epsilon}{sub iso}). The measurement finds BR(B{sup {+-}} {yields} {phi}K{sup {+-}})/BR(B{sup {+-}} {yields} J/{psi}K{sup {+-}}) = 0.0068 {+-} 0.0021(stat.) {+-} 0.0007(syst.). The B{sup {+-}} {yields} {phi}K{sup {+-}} branching ratio is then found to be BR(B{sup {+-}} {yields} {phi}K{sup {+-}}) = [6.9 {+-} 2.1(stat.) {+-} 0.8(syst.)] x 10{sup -6}. This value is consistent with similar measurements reported by the e{sup +}e{sup -} collider experiments BaBar[1], Belle[2], and CLEO[3].

  8. LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC

    SciTech Connect (OSTI)

    Song, Rak-Hyun; Shin, Dong Ryul; Dokiya, Masayuki

    1996-12-31

    In the planar SOFC, the interconnect materials plays two roles as an electrical connection and as a gas separation plate in a cell stack. The interconnect materials must be chemically stable in reducing and oxidizing environments, and have high electronic conductivity, high thermal conductivity, matching thermal expansion with an electrolyte, high mechanical strength, good fabricability, and gas tightness. Lanthanum chromite so far has been mainly used as interconnect materials in planar SOFC. However, the ceramic materials are very weak in mechanical strength and have poor machining property as compared with metal. Also the metallic materials have high electronic conductivity and high thermal conductivity. Recently some researchers have studied metallic interconnects such as Al{sub 2}O{sub 3}/Inconel 600 cermet, Ni-20Cr coated with (LaSr)CoO{sub 3}, and Y{sub 2}O{sub 3-} or La{sub 2}O{sub 3}-dispersed Cr alloy. These alloys have still some problems because Ni-based alloys have high thermal expansion, the added Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3} and La{sub 2}O{sub 3} to metals have no electronic conductivity, and the oxide formed on the surface of Cr alloy has high volatility. To solve these problems, in this study, LaCrO{sub 3}-dispersed Cr for metallic interconnect of planar SOFC was investigated. The LaCrO{sub 3}-dispersed Cr can be one candidate of metallic interconnect because LaCrO{sub 3} possesses electronic conductivity and Cr metal has relatively low thermal expansion. The content of 25 vol.% LaCrO{sub 3} Was selected on the basis of a theoretically calculated thermal expansion. The thermal expansion, electrical and oxidation properties were examined and the results were discussed as related to SOFC requirements.

  9. Microstructural and mechanical characteristics of Ni–Cr thin films

    SciTech Connect (OSTI)

    Petley, Vijay; Sathishkumar, S.; Thulasi Raman, K.H.; Rao, G.Mohan; Chandrasekhar, U.

    2015-06-15

    Highlights: • Ni–Cr thin films of varied composition deposited by DC magnetron co-sputtering. • Thin film with Ni–Cr: 80–20 at% composition exhibits most distinct behavior. • The films were tensile tested and exhibited no cracking till the substrate yielding. - Abstract: Ni–Cr alloy thin films have been deposited using magnetron co-sputtering technique at room temperature. Crystal structure was evaluated using GIXRD. Ni–Cr solid solution upto 40 at% of Cr exhibited fcc solid solution of Cr in Ni and beyond that it exhibited bcc solid solution of Ni in Cr. X-ray diffraction analysis shows formation of (1 1 1) fiber texture in fcc and (2 2 0) fiber texture in bcc Ni–Cr thin films. Electron microscopy in both in-plane and transverse direction of the film surface revealed the presence of columnar microstructure for films having Cr upto 40 at%. Mechanical properties of the films are evaluated using nanoindentation. The modulus values increased with increase of Cr at% till the film is fcc. With further increase in Cr at% the modulus values decreased. Ni–Cr film with 20 at% Ni exhibits reduction in modulus and is correlated to the poor crystallization of the film as reflected in XRD analysis. The Ni–Cr thin film with 80 at% Ni and 20 at% Cr exhibited the most distinct columnar structure with highest electrical resistivity, indentation hardness and elastic modulus.

  10. Morphology, deformation, and defect structures of TiCr{sub 2} in Ti-Cr alloys

    SciTech Connect (OSTI)

    Chen, K.C.; Allen, S.M.; Livingston, J.D.

    1992-12-31

    The morphologies and defect structures of TiCr{sub 2} in several Ti-Cr alloys have been examined by optical metallography, x-ray diffraction, and transmission electron microscopy (TEM), in order to explore the room-temperature deformability of the Laves phase TiCr{sub 2}. The morphology of the Laves phase was found to be dependent upon alloy composition and annealing temperature. Samples deformed by compression have also been studied using TEM. Comparisons of microstructures before and after deformation suggest an increase in twin, stacking fault, and dislocation density within the Laves phase, indicating some but not extensive room-temperature deformability.

  11. Kinetics and Mechanism of the Hydrogenation of CpCr(CO)3/[CpCr(CO)3]2 Equilibrium to CpCr(CO)3H

    SciTech Connect (OSTI)

    Norton, Jack R.; Spataru, Tudor; Camaioni, Donald M.; Lee, Suh-Jane; Li, Gang; Choi, Jongwook; Franz, James A.

    2014-05-26

    The kinetics of the hydrogenation of 2 CpCr(CO)3/[CpCr(CO)3]2 to CpCr(CO)3H has been investigated. The reaction is second-order in Cr and first-order in H2, with a rate constant of 45 M 2s 1 at 25 C in benzene. DFT calculations rule out an H2 complex as an intermediate, and suggest (a) end-on approach of H2 to one Cr of [CpCr(CO)3]2 as the Cr-Cr bond undergoes heterolytic cleavage, (b) heterolytic cleavage of the coordinated H2 between O and Cr, and (c) isomerization of the resulting O-protonated CpCr(CO)2(COH) to CpCr(CO)3H. The work at Pacific Northwest National Laboratory (PNNL) was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences; Battelle operates PNNL for DOE.

  12. Growth of Cr-Nitrides on Commercial Ni-Cr and Fe-Cr Base Alloys to Protect PEMFC Bipolar Plates

    SciTech Connect (OSTI)

    Brady, Michael P; Wang, Heli; Yang, Bing; Turner, John; Bordignon, Melanie; Molins, Regine; Abdelhamid, Mahmoud; Lipp, Ludwig; Walker, Larry R

    2007-01-01

    Nitridation of Cr-bearing alloys can yield low interfacial contact resistance (ICR), electrically- conductive and corrosion-resistant CrN or Cr2N base surfaces of interest for a range of electrochemical devices, including fuel cells, batteries, and sensors. This paper presents results of exploratory studies of the nitridation of two high Cr (30-35 wt%) commercially available Ni-Cr alloys and a ferritic high Cr (29 wt.%) stainless steel for proton exchange membrane fuel cell (PEMFC) bipolar plates. A high degree of corrosion resistance in sulfuric acid solutions designed to simulate bipolar plate conditions and low ICR values were achieved via nitridation. Oxygen impurities in the nitriding environment were observed to play a significant role in the nitrided surface structures that formed, with detrimental effects for the Ni-Cr base alloys, but beneficial effects for the stainless steel alloy. Results of single-cell fuel cell testing are also presented.

  13. Hazard Evaluation for 244-CR Vault

    SciTech Connect (OSTI)

    GRAMS, W.H.

    1999-08-19

    This document presents the results of a hazards identification and evaluation performed on the 244-CR Vault to close a USQ (USQ No.TF-98-0785, Potential Inadequacy in Authorization Basis (PIAB): To Evaluate Miscellaneous Facilities Listed In HNF-2503 And Not Addressed In The TWRS Authorization Basis) that was generated as part of an evaluation of inactive TWRS facilities.

  14. Guide to Developing Air-Cooled Lithium Bromide (LiBr) Absorption for CHP Applications, April 2005

    Office of Energy Efficiency and Renewable Energy (EERE)

    Development status of air-cooled lithium bromide (LiBr)-water absorption chillers for cooling, heating, and power (CHP) system applications in light-commercial buildings.

  15. Very fast doped LaBr.sub.3 scintillators and time-of-flight PET

    DOE Patents [OSTI]

    Shah, Kanai S.

    2006-10-31

    The present invention concerns very fast scintillator materials capable of resolving the position of an annihilation event within a portion of a human body cross-section. In one embodiment, the scintillator material comprises LaBr.sub.3 doped with cerium. Particular attention is drawn to LaBr.sub.3 doped with a quantity of Ce that is chosen for improving the timing properties, in particular the rise time and resultant timing resolution of the scintillator, and locational capabilities of the scintillator.

  16. LAKESHORE AVON BR ANT-EDEN ALD EN-LANC ASTER AU BURN W SH ELDON

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

    81 § ¨ ¦ 81 LAKESHORE AVON BR ANT-EDEN ALD EN-LANC ASTER AU BURN W SH ELDON CALEDONIA HURON C REEK LEIC EST ER COL DEN ASH FORD INDIAN FALLS LAWTONS SAR DINIA RPD-037 -2 GLENWOOD PU LASKI PAVILION CON CORD COL LINS N ELM A ORC HARD PARK-H AMBU RG DANLEY CORNERS ST ILLWAT ER CHAFF EE-ARCAD E FAYETT E-WATERLOO LAKEVIEW JAVA SEN EC A W ELLER Y AU RORA E ZOAR BU FFALO TIOGA SILVER LAKE AKR ON ROM E RAT HBON E ALM A BET HANY WYOMING ULYSSES BR ANCH W SAN DY CREEK COL LINS BLOOMFIELD E LEBANON

  17. Attachment I CHPRC CONDITION REPORT FORM Status: Analysis CR NUMBER: CR-2011I 2037

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

    CHPRC CONDITION REPORT FORM Status: Analysis CR NUMBER: CR-2011I 2037 Issue Identification and Processing Initiator: Initiating IDetifed Bannister, Roland J Document: 6/23/2011d Title of Issue: Extent of Condition review for S3000 containers Description of Issue: Extent of Condition Review arose from the Causal Analysis regarding the breached drum found in 2404WB on April 26, 2011. The scope of the review was to assess all other known S3000 (homogenous solids) waste streams to identify

  18. Dual-phase Cr-Ta alloys for structural applications

    DOE Patents [OSTI]

    Liu, Chain T.; Brady, Michael P.; Zhu, Jiahong; Tortorelli, Peter F.

    2001-01-01

    Dual phase alloys of chromium containing 2 to 11 atomic percent tantalum with minor amounts of Mo, Cr, Ti, Y, La, Cr, Si and Ge are disclosed. These alloys contain two phases including Laves phase and Cr-rich solid solution in either eutectic structures or dispersed Laves phase particles in the Cr-rich solid solution matrix. The alloys have superior mechanical properties at high temperature and good oxidation resistance when heated to above 1000.degree. C. in air.

  19. CALiPER Application Summary Report 16. LED BR30 and R30 Lamps

    SciTech Connect (OSTI)

    none,

    2012-07-01

    This report analyzes the independently tested performance of 13 LED products labeled as BR30 or R30 lamps. The test results indicate substantial improvement versus earlier CALiPER testing of similar products, and performance comparable to recent data from LED Lighting Facts and ENERGY STAR.

  20. Cr-doped scandium borate laser

    DOE Patents [OSTI]

    Chai, Bruce H.; Lai, Shui T.; Long, Margaret N.

    1989-01-01

    A broadly wavelength-tunable laser is provided which comprises as the laser medium a single crystal of MBO.sub.3 :Cr.sup.3+, where M is selected from the group of Sc, In and Lu. The laser may be operated over a broad temperature range from cryogenic temperatures to elevated temperatures. Emission is in a spectral range from red to infrared, and the laser is useful in the fields of defense, communications, isotope separation, photochemistry, etc.

  1. Temporal evolution of ion energy distribution functions and ion charge states of Cr and Cr-Al pulsed arc plasmas

    SciTech Connect (OSTI)

    Tanaka, Koichi; Anders, André

    2015-11-15

    To study the temporal evolution of ion energy distribution functions, charge-state-resolved ion energy distribution functions of pulsed arc plasmas from Cr and Cr-Al cathodes were recorded with high time resolution by using direct data acquisition from a combined energy and mass analyzer. The authors find increases in intensities of singly charged ions, which is evidence that charge exchange reactions took place in both Cr and Cr-Al systems. In Cr-Al plasmas, the distributions of high-charge-state ions exhibit high energy tails 50 μs after discharge ignition, but no such tails were observed at 500 μs. The energy ratios of ions of different charge states at the beginning of the pulse, when less neutral atoms were in the space in front of the cathode, suggest that ions are accelerated by an electric field. The situation is not so clear after 50 μs due to particle collisions. The initial mean ion charge state of Cr was about the same in Cr and in Cr-Al plasmas, but it decreased more rapidly in Cr-Al plasmas compared to the decay in Cr plasma. The faster decay of the mean ion charge state and ion energy caused by the addition of Al into a pure Cr cathode suggests that the mean ion charge state is determined not only by ionization processes at the cathode spot but also by inelastic collision between different elements.

  2. AmeriFlux BR-Sa1 Santarem-Km67-Primary Forest

    SciTech Connect (OSTI)

    Saleska, Scott

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site BR-Sa1 Santarem-Km67-Primary Forest. Site Description - The LBA Tapajos KM67 Mature Forest site is located in the Tapajos National Forest, a 450,000 ha closed-canopy upland forest in Amazonian Brazil. Bounded by the Tapajos River in the west and highway BR-163 to the east, the tower is located on a flat plateau (or planalto) that extends up to 150 km to the north, south, and east. Within the confines of the National Forest, anthropogenic disturbances are limited to a few small hunting trails. The surrounding stand is classified as primary or "old-growth"" predominantly by its uneven age distribution, emergent trees, numerous epiphytes and abundant large logs. In 2007 falling trees hit the tower guy wires rendering all instrumentation in-operational. After a complete restoration tower measurements resumed in August of 2008.

  3. Cr segregation at the FeCr surface and the origin of corrosion resistance in ferritic steels

    SciTech Connect (OSTI)

    De Caro, M S; Morse, B; Egiebor, N; Farmer, J; Caro, A

    2008-11-22

    Structural materials in Gen-IV nuclear reactors will face severe conditions of high operating temperatures, high neutron flux exposure, and corrosive environment. Radiation effects and corrosion and chemical compatibility issues are factors that will limit the materials lifetime. Low-chromium (9-12 Cr wt.%) ferritic martensitic (F/M) steels are being considered as possible candidates because they offer good swelling resistance and good mechanical properties under extreme conditions of radiation dose and irradiation temperature. The surface chemistry of FeCr alloys, responsible for the corrosion properties, is complex. It exists today a controversy between equilibrium thermodynamic calculations, which suggest Cr depletion at the surface driven by the higher surface energy of Cr, and experimental data which suggest the oxidation process occurs in two stages, first forming a Fe-rich oxide, followed by a duplex oxide layer, and ending with a Cr-rich oxide. Moreover, it has been shown experimentally that corrosion resistance of F/M steels depends significantly on Cr content, increasing with increasing Cr content and with a threshold around 10% Cr, below which, the alloy behaves as pure Fe. In an attempt to rationalize these two contradicting observations and to understand the physical mechanism behind corrosion resistance in these materials we perform atomistic simulations using our FeCr empirical potential and analyze Cr equilibrium distributions at different compositions and temperatures in single and polycrystalline samples. We analyze the controversy in terms of thermodynamic and kinetic considerations.

  4. Spectroscopic Evidence for a High-Spin Br-Fe(IV)-Oxo Intermediate in the

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

    alpha-Ketoglutarate-Dependent Halogenase CytC3 from Streptomyces Working title - Spectroscopic Evidence for a High-Spin Br-Fe(IV)-Oxo Intermediate in the alpha-Ketoglutarate-Dependent Halogenase CytC3 from Streptomyces There are over 4,500 known halogenated natural products. The presence of a halogen in the molecular framework tunes a compound's chemical reactivity or biological activity in these natural fungicides and antibiotics. Four classes of enzymes are now known to catalyze

  5. Investigation into Nanostructured Lanthanum Halides and CeBr{sub 3} for Nuclear Radiation Detection

    SciTech Connect (OSTI)

    Guss, P., Guise, R., Mukhopadhyay, S., Yuan, D.

    2011-06-22

    This slide-show presents work on radiation detection with nanostructured lanthanum halides and CeBr{sub 3}. The goal is to extend the gamma energy response on both low and high-energy regimes by demonstrating the ability to detect low-energy x-rays and relatively high-energy activation prompt gamma rays simultaneously using the nano-structured lanthanum bromide, lanthanum fluoride, cerium bromide, or other nanocrystal material. Homogeneous and nano structure cases are compared.

  6. Response of LaBr{sub 3}(Ce) scintillators to 2.5 MeV fusion neutrons

    SciTech Connect (OSTI)

    Cazzaniga, C.; Nocente, M.; Gorini, G.; Istituto di Fisica del Plasma, Associazione EURATOM-ENEA-CNR, Via Roberto Cozzi 53, Milano 20125 ; Tardocchi, M.; Croci, G.; Giacomelli, L.; Angelone, M.; Pillon, M.; Villari, S.; Weller, A.; Petrizzi, L.; Collaboration: ASDEX Upgrade Team; JET-EFDA Contributors

    2013-12-15

    Measurements of the response of LaBr{sub 3}(Ce) to 2.5 MeV neutrons have been carried out at the Frascati Neutron Generator and at tokamak facilities with deuterium plasmas. The observed spectrum has been interpreted by means of a Monte Carlo model. It is found that the main contributor to the measured response is neutron inelastic scattering on {sup 79}Br, {sup 81}Br, and {sup 139}La. An extrapolation of the count rate response to 14 MeV neutrons from deuterium-tritium plasmas is also presented. The results are of relevance for the design of ?-ray diagnostics of fusion burning plasmas.

  7. Characterization of low-melting electrolytes for potential geothermal borehole power supplies: The LiBr-KBr-LiF eutectic

    SciTech Connect (OSTI)

    Guidotti, R.A.; Reinhardt, F.W.

    1998-05-01

    The suitability of modified thermal-battery technology for use as a potential power source for geothermal borehole applications is under investigation. As a first step, the discharge processes that take place in LiSi/LiBr-KBr-LiF/FeS{sub 2} thermal cells were studied at temperatures of 350 C and 400 C using pelletized cells with immobilized electrolyte. Incorporation of a reference electrode allowed the relative contribution of each electrode to the overall cell polarization to be determined. The results of single-cell tests are presented, along with preliminary data for cells based on a lower-melting CsBr-LiBr-KBr eutectic salt.

  8. Optimization of electrode characteristics for the Br-2/H-2 redox flow cell

    SciTech Connect (OSTI)

    Tucker, MC; Cho, KT; Weber, AZ; Lin, GY; Nguyen, TV

    2014-10-17

    The Br-2/H-2 redox flow cell shows promise as a high-power, low-cost energy storage device. The effect of various aspects of material selection, processing, and assembly of electrodes on the operation, performance, and efficiency of the system is determined. In particular, (+) electrode thickness, cell compression, hydrogen pressure, and (-) electrode architecture are investigated. Increasing hydrogen pressure and depositing the (-) catalyst layer on the membrane instead of on the carbon paper backing layers have a large positive impact on performance, enabling a limiting current density above 2 A cm(-2) and a peak power density of 1.4 W cm(-2). Maximum energy efficiency of 79 % is achieved. In addition, the root cause of limiting-current behavior in this system is elucidated, where it is found that Br- reversibly adsorbs at the Pt (-) electrode for potentials exceeding a critical value, and the extent of Br- coverage is potential-dependent. This phenomenon limits maximum cell current density and must be addressed in system modeling and design. These findings are expected to lower system cost and enable higher efficiency.

  9. Laser cooling of MgCl and MgBr in theoretical approach

    SciTech Connect (OSTI)

    Wan, Mingjie; Shao, Juxiang; Huang, Duohui; Yang, Junsheng; Cao, Qilong; Jin, Chengguo; Wang, Fanhou; Gao, Yufeng

    2015-07-14

    Ab initio calculations for three low-lying electronic states (X{sup 2}Σ{sup +}, A{sup 2}Π, and 2{sup 2}Π) of MgCl and MgBr molecules, including spin-orbit coupling, are performed using multi-reference configuration interaction plus Davidson correction method. The calculations involve all-electronic basis sets and Douglas–Kroll scalar relativistic correction. Spectroscopic parameters well agree with available theoretical and experimental data. Highly diagonally distributed Franck-Condon factors f{sub 00} for A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) are determined for both MgCl and MgBr molecules. Suitable radiative lifetimes τ of A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) states for rapid laser cooling are also obtained. The proposed laser drives A{sup 2}Π{sub 3/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) transition by using three wavelengths (main pump laser λ{sub 00}; two repumping lasers λ{sub 10} and λ{sub 21}). These results indicate the probability of laser cooling MgCl and MgBr molecules.

  10. Closed-cage (fullerene-like) structures of NiBr{sub 2}

    SciTech Connect (OSTI)

    Bar-Sadan, M.; Popovitz-Biro, R.; Prior, Yehiam; Tenne, R. . E-mail: reshef.tenne@weizmann.ac.il

    2006-11-09

    It is well accepted by now that nanoparticles of inorganic layered compounds form closed-cage structures (IF). In particular closed-cage nanoparticles of metal dihalides, like NiCl{sub 2}, CdCl{sub 2} and CdI{sub 2} were shown to produce such structures in the past. In the present report IF-NiBr{sub 2} polyhedra and quasi-spherical structures were obtained by the evaporation/recrystallization technique as well as by laser ablation. When the nanoclusters were formed in humid atmosphere, nickel perbromate hydrate [Ni(BrO{sub 4}){sub 2}(H{sub 2}O){sub 6}] polyhedra and short tubules were produced, as a result of a reaction with water. Nanooctahedra of NiBr{sub 2} were found occasionally in the irradiated soot. The reoccurrence of this structure in the IF family suggests that it is a generic one. Consistent with previous observations, this study showed that formation of the IF materials stabilized the material under the electron-beam irradiation. The growth mechanism of these nanostructures is briefly discussed.

  11. A modified Stillinger-Weber potential for TlBr and its polymorphic extension

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

    Zhou, Xiaowang; Foster, Michael E.; Jones, Reese E.; Doty, F. Patrick; Yang, Pin; Fan, Hongyou

    2015-04-30

    TlBr is promising for g- and x- radiation detection, but suffers from rapid performance degradation under the operating external electric fields. To enable molecular dynamics (MD) studies of this degradation, we have developed a Stillinger-Weber type of TlBr interatomic potential. During this process, we have also addressed two problems of wider interests. First, the conventional Stillinger-Weber potential format is only applicable for tetrahedral structures (e.g., diamond-cubic, zinc-blende, or wurtzite). Here we have modified the analytical functions of the Stillinger-Weber potential so that it can now be used for other crystal structures. Second, past modifications of interatomic potentials cannot always bemore » applied by a broad community because any new analytical functions of the potential would require corresponding changes in the molecular dynamics codes. Here we have developed a polymorphic potential model that simultaneously incorporates Stillinger-Weber, Tersoff, embedded-atom method, and any variations (i.e., modified functions) of these potentials. As a result, we have implemented this polymorphic model in MD code LAMMPS, and demonstrated that our TlBr potential enables stable MD simulations under external electric fields.« less

  12. Optimization of electrode characteristics for the Br?/H? redox flow cell

    SciTech Connect (OSTI)

    Tucker, Michael C.; Cho, Kyu Taek; Weber, Adam Z.; Lin, Guangyu; Van Nguyen, Trung

    2015-01-01

    The Br?/H? redox flow cell shows promise as a high-power, low-cost energy storage device. The effect of various aspects of material selection, processing, and assembly of electrodes on the operation, performance, and efficiency of the system is determined. In particular, (+) electrode thickness, cell compression, hydrogen pressure, and () electrode architecture are investigated. Increasing hydrogen pressure and depositing the () catalyst layer on the membrane instead of on the carbon-paper backing layers have a large positive impact on performance, enabling a limiting current density above 2 A cm-2 and a peak power density of 1.4 W cm-2. Maximum energy efficiency of 79% is achieved. In addition, the root cause of limiting-current behavior in this system is elucidated, where it is found that Br- reversibly adsorbs at the Pt () electrode for potentials exceeding a critical value, and the extent of Br- coverage is potential-dependent. This phenomenon limits maximum cell current density and must be addressed in system modeling and design. These findings are expected to lower system cost and enable higher efficiency.

  13. A modified Stillinger-Weber potential for TlBr and its polymorphic extension

    SciTech Connect (OSTI)

    Zhou, Xiaowang; Foster, Michael E.; Jones, Reese E.; Doty, F. Patrick; Yang, Pin; Fan, Hongyou

    2015-04-30

    TlBr is promising for g- and x- radiation detection, but suffers from rapid performance degradation under the operating external electric fields. To enable molecular dynamics (MD) studies of this degradation, we have developed a Stillinger-Weber type of TlBr interatomic potential. During this process, we have also addressed two problems of wider interests. First, the conventional Stillinger-Weber potential format is only applicable for tetrahedral structures (e.g., diamond-cubic, zinc-blende, or wurtzite). Here we have modified the analytical functions of the Stillinger-Weber potential so that it can now be used for other crystal structures. Second, past modifications of interatomic potentials cannot always be applied by a broad community because any new analytical functions of the potential would require corresponding changes in the molecular dynamics codes. Here we have developed a polymorphic potential model that simultaneously incorporates Stillinger-Weber, Tersoff, embedded-atom method, and any variations (i.e., modified functions) of these potentials. As a result, we have implemented this polymorphic model in MD code LAMMPS, and demonstrated that our TlBr potential enables stable MD simulations under external electric fields.

  14. Re-evaluation of the eutectic region of the LiBr-KBr-LiF system

    SciTech Connect (OSTI)

    Redey, L.; Guidotti, R.A.

    1996-05-01

    The separator pellet in a thermal battery consists of electrolyte immobilized by a binder (typically, MgO powder). The melting point of the electrolyte determines the effective operating window for its use in a thermal battery. The development of a two-hour thermal battery required the use of a molten salt that had a lower melting point and larger liquidus range than the LiCl-KCl eutectic which melts at 352 C. Several candidate eutectic electrolyte systems were evaluated for their suitability for this application. One was the LiCl-LiBr-KBr eutectic used at Argonne National Laboratories for high-temperature rechargeable batteries for electric-vehicle applications. Using a custom-designed high-temperature conductivity cell, the authors were able to readily determine the liquidus region for the various compositions studied around the original eutectic for the LiBr-KBr-LiF system. The actual eutectic composition was found to be 60.0 m/o LiBr-37.5 m/o KBr-2.5 m/o LiF with a melting point of 324 {+-} 0.5 C.

  15. Geothermal br Resource br Area Geothermal br Resource br Area...

    Open Energy Info (EERE)

    Aluto Langano Geothermal Area Aluto Langano Geothermal Area East African Rift System Ethiopian Rift Valley Major Normal Fault Basalt MW K Amatitlan Geothermal Area Amatitlan...

  16. Mechanical properties of irradiated 9Cr-2WVTa steel

    SciTech Connect (OSTI)

    Klueh, R.L.; Alexander, D.J.; Rieth, M.

    1998-09-01

    An Fe-9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa) steel has excellent strength and impact toughness before and after irradiation in the Fast Flux Test Facility and the High Flux Reactor (HFR). The ductile-brittle transition temperature (DBTT) increased only 32 C after 28 dpa at 365 C in FFTF, compared to a shift of {approx}60 C for a 9Cr-2WV steel--the same as the 9Cr-2WVTa steel but without tantalum. This difference occurred despite the two steels having similar tensile but without tantalum. This difference occurred despite the two steels having similar tensile properties before and after irradiation. The 9Cr-2WVTa steel has a smaller prior-austenite grain size, but otherwise microstructures are similar before irradiation and show similar changes during irradiation. The irradiation behavior of the 9Cr-2WVTa steel differs from the 9Cr-2WV steel and other similar steels in two ways: (1) the shift in DBTT of the 9Cr-2WVTa steel irradiated in FFTF does not saturate with fluence by {approx}28 dpa, whereas for the 9Cr-2WV steel and most similar steels, saturation occurs at <10 dpa, and (2) the shift in DBTT for 9Cr-2WVTa steel irradiated in FFTF and HFR increased with irradiation temperature, whereas it decreased for the 9Cr-2WV steel, as it does for most similar steels. The improved properties of the 9Cr-2WVTa steel and the differences with other steels were attributed to tantalum in solution.

  17. SF6432-CR (02-01-13) Cost Reimbursement

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

    labor are authorized as direct charges Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy Department Release Date: 11...

  18. SF6432-CR (02-01-12) Cost Reimbursement

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

    as direct charges to this contract Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy & Quality Dept Release Date:...

  19. SF6432-CR (02-01-13) Cost Reimbursement

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

    by Part 931 of the DEAR by a Sandia audit. Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy Department Release Date: 04...

  20. Development of Surface Complexation Models of Cr(VI) Adsorption...

    Office of Scientific and Technical Information (OSTI)

    Cr(VI) Adsorption on Soils, Sediments and Model Mixtures of Kaolinite, Montmorillonite, ... into aquifers and shallow sediments and soils via many anthropogenic activities. ...

  1. SF6432-CR (02-01-13) Cost Reimbursement

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

    a Government site to perform work shall have Control : SF 6432-CR Title: Standard Terms & Conditions for Cost Reimbursement Owner: Procurement Policy & Quality Dept Release...

  2. SF6432-CR (02-01-12) Cost Reimbursement

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

    ... prior to any attempts to enter a government site as shown ... premises are subject to search. (e) Contractor will ... SF 6432-CR Title: Standard Terms & Conditions for Cost ...

  3. SF6432-CR (02-01-13) Cost Reimbursement

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

    ... who will enter a Government site to perform work shall have Control : SF 6432-CR Title: Standard Terms & Conditions ... premises are subject to search. (e) Contractor will ...

  4. Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo

    SciTech Connect (OSTI)

    Niu, C.; Zaddach, A. J.; Oni, A. A.; Sang, X.; LeBeau, J. M.; Koch, C. C.; Irving, D. L.; Hurt, J. W.

    2015-04-20

    Spin-driven ordering of Cr in an equiatomic fcc NiFeCrCo high entropy alloy (HEA) was predicted by first-principles calculations. Ordering of Cr is driven by the reduction in energy realized by surrounding anti-ferromagnetic Cr with ferromagnetic Ni, Fe, and Co in an alloyed L1{sub 2} structure. The fully Cr-ordered alloyed L1{sub 2} phase was predicted to have a magnetic moment that is 36% of that for the magnetically frustrated random solid solution. Three samples were synthesized by milling or casting/annealing. The cast/annealed sample was found to have a low temperature magnetic moment that is 44% of the moment in the milled sample, which is consistent with theoretical predictions for ordering. Scanning transmission electron microscopy measurements were performed and the presence of ordered nano-domains in cast/annealed samples throughout the equiatomic NiFeCrCo HEA was identified.

  5. Measurement of ratio R = (BR(D{sup 0}{yields}K{pi}{pi}{pi})/BR(D{sup 0}{yields}K{pi})) in {pi}{sup -}-Nucleus interactions at 500 GeV/c

    SciTech Connect (OSTI)

    Solano Salinas, C. J.; Paucarchuco, C.; Fernandez, A.; Sheaff, M.

    2007-10-26

    We report a very preliminary result on the measurement of the ratio of branching ratios, for two decays D{sup 0} meson, R = (BR(D{sup 0}{yields}K{pi}{pi}{pi})/BR(D{sup 0}{yields}K{pi})), using data from the E791 experiment. We find R = 1.96{+-}0.0286 (stat){+-}0.06 (sys). This is in agreement with and of similar precision to the current PDG average value 1.97{+-}0.09.

  6. Magnetic properties and hyperfine interactions in Cr8, Cr7Cd, and Cr7Ni molecular rings from 19F-NMR

    SciTech Connect (OSTI)

    Bordonali, L; Garlatti, E; Casadei, C M; Furukawa, Y; Lascialfari, A; Carretta, S; Troiani, F; Timco, G; Winpenny, R E; Borsa, F

    2014-04-14

    A detailed experimental investigation of the 19F nuclear magnetic resonance is made on single crystals of the homometallic Cr8 antiferromagnetic molecular ring and heterometallic Cr7Cd and Cr7 Ni rings in the low temperature ground state. Since the F? ion is located midway between neighboring magnetic metal ions in the ring, the 19F-NMR spectra yield information about the local electronic spin density and 19F hyperfine interactions. In Cr8, where the ground state is a singlet with total spin S T = 0, the 19F-NMR spectra at 1.7 K and low external magnetic field display a single narrow line, while when the magnetic field is increased towards the first level crossing field, satellite lines appear in the 19F-NMR spectrum, indicating a progressive increase in the Boltzmann population of the first excited state S T = 1. In the heterometallic rings, Cr7Cd and Cr7 Ni, whose ground state is magnetic with S T = 3/2 and S T = 1/2, respectively, the 19F-NMR spectrum has a complicated structure which depends on the strength and orientation of the magnetic field, due to both isotropic and anisotropic transferred hyperfine interactions and classical dipolar interactions. From the 19F-NMR spectra in single crystals we estimated the transferred hyperfine constants for both the F?-Ni2+ and the F?-Cd2+ bonds. The values of the hyperfine constants compare well to the ones known for F?-Ni2+ in KNiF3 and NiF2 and for F?-Cr3+ in K2NaCrF6. The results are discussed in terms of hybridization of the 2s, 2p orbitals of the F? ion and the d orbitals of the magnetic ion. Finally, we discuss the implications of our results for the electron-spin decoherence.

  7. Characterization of Cr-rich Cr-Sb multilayer films: Syntheses of a new metastable phase using modulated elemental reactants

    SciTech Connect (OSTI)

    Regus, Matthias; Mankovsky, Sergiy; Polesya, Svitlana; Kuhn, Gerhard; Ditto, Jeffrey; Schürmann, Ulrich; Jacquot, Alexandre; Bartholomé, Kilian; Näther, Christian; Winkler, Markus; König, Jan D.; Böttner, Harald; Kienle, Lorenz; Johnson, David C.; Ebert, Hubert; Bensch, Wolfgang

    2015-10-15

    The new metastable compound Cr{sub 1+x}Sb with x up to 0.6 has been prepared via a thin film approach using modulated elemental reactants and investigated by in-situ X-ray reflectivity, X-ray diffraction, differential scanning calorimetry, energy dispersive X-ray analysis as well as transmission electron microscopy and atomic force microscopy. The new Cr-rich antimonide crystallizes in a structure related to the Ni{sub 2}In-type structure, where the crystallographic position (1/3, 2/3, 3/4) is partially occupied by excess Cr. The elemental layers of the pristine material interdiffused significantly before Cr{sub 1+x}Sb crystallized. A change in the activation energy was observed for the diffusion process when crystal growth starts. First-principles electronic structure calculations provide insight into the structural stability, magnetic properties and resistivity of Cr{sub 1+x}Sb. - Graphical abstract: 1 amorphous multilayered film 2 interdiffused amorphous film 3 metastable crystalline phase 4 thermodynamic stable phase (and by-product). - Highlights: • Interdiffusion of amorphous Cr and Sb occurs before crystallization. • Crystallization of a new metastable phase Cr{sub 1.6}Sb in Ni{sub 2}In-type structure. • The new Cr-rich phase shows half-metallic behavior.

  8. AmeriFlux US-Br1 Brooks Field Site 10- Ames

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Parkin, Tim [USDA; Prueger, John [National Laboratory for Agriculture and the Environment

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Br1 Brooks Field Site 10- Ames. Site Description - The Brooks Field Site 10 - Ames Site is one of three sites (Brooks Field Site 11 and Brooks Field Site 1011) located in a corn/soybean agricultural landscape of central Iowa. The farming systems, associated tillage, and nutrient management practices for soybean/corn production are typical of those throughout Upper Midwest Corn Belt. All three sites are members of the AmeriFlux network. Information for all three can be found in synchronous pages of this website.

  9. AmeriFlux US-Br3 Brooks Field Site 11- Ames

    SciTech Connect (OSTI)

    Parkin, Tim; Prueger, John

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Br3 Brooks Field Site 11- Ames. Site Description - The Brooks Field Site 11 - Ames Site is one of three sites (Brooks Field Site 10 and Brooks Field Site 1011) located in a corn/soybean agricultural landscape of central Iowa. The farming systems, associated tillage, and nutrient management practices for soybean/corn production are typical of those throughout Upper Midwest Corn Belt. All three sites are members of the AmeriFlux network. Information for all three can be found in synchronous pages of this website.

  10. Br-rich Tips of Calcified Crab Claws are Less Hard but More Fracture

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

    Resistant: A Comparison of Mineralized and Heavy-element Biological Materials Br-rich Tips of Calcified Crab Claws are Less Hard but More Fracture Resistant: A Comparison of Mineralized and Heavy-element Biological Materials figure 1 Figure 1. The heavy element biomaterial is the darker material at the tip of the shore crab claws. Figure "b" shows the same claw as "a" but after bead blasting. The claw tips are less eroded by the bead blasting than surrounding calcified

  11. 244-CR Vault Interim Stabilization Project Plan

    SciTech Connect (OSTI)

    PARKMAN, D.B.

    2000-04-25

    The 244-CR Vault is a two-level, multi-cell structure of reinforced concrete constructed below grade. The lower cell contains four individual compartments, each containing a steel process storage tank and equipped with a concrete sump. The upper cell contains the piping and support equipment, and has two compartments for each of the tanks. The ''pump pit'' is accessed by the removal of concrete cover blocks, while the smaller ''riser pit'' is accessed by steel cover plates. The facility most recently was used as a double-contained receiver tank (DCRT). A DCRT is a type of waste transfer tank that together with its related equipment constitutes a short-term storage area for liquid waste and has a pump pit for waste transfer operations. This vault most recently was used for short-term storage and waste routing for saltwell liquid pumped from the 241-C Tank Farm in the 200 East Area. Waste transfer lines are connected inside the pump pit by a jumper installed between connecting nozzles. An active ventilation system is in operation at the 244-CR vault. Ventilation supply air enters the upper vault section through an inlet header with some leakage through the spaces between the cell cover blocks. The upper and lower vaults are connected by exhauster ports, which allow airflow between the two sections. Normal flow moves air from the upper cell to the lower cell where it is removed and routed into a filter plenum; there the air is treated by a bank of four prefilters and two banks of high-efficiency particulate air (HEPA) filters (each containing four HEPAs). The air is exhausted to the atmosphere through the 296-C-05 Stack. The stack is equipped with a record sampler and continuous air monitor. Two fans (each rated at 4,200 cubic feet per minute) installed downstream of the filtration system provide the motive force for exhausting the vaults and the tanks. As an active system, it is operated continuously with only one of the two fans required to operate at a time. A

  12. Interlayer coupling in Fe/Cr/Gd multilayer structures

    SciTech Connect (OSTI)

    Drovosekov, A. B. Kreines, N. M.; Savitsky, A. O.; Kravtsov, E. A.; Blagodatkov, D. V.; Ryabukhina, M. V.; Milyaev, M. A.; Ustinov, V. V.; Pashaev, E. M.; Subbotin, I. A.; Prutskov, G. V.

    2015-06-15

    The effect of the chromium layer thickness on the magnetic state of an [Fe/Cr/Gd/Cr]{sub n} multilayer structure is studied. A series of Fe/Cr/Gd structures with Cr spacer thicknesses of 4–30 Å is studied by SQUID magnetometry and ferromagnetic resonance in the temperature range 4.2–300 K. The obtained experimental results are described in terms of an effective field model, which takes into account a biquadratic contribution to the interlayer coupling energy and a nonuniform magnetization distribution inside the gadolinium layer (which was detected earlier). Depending on the magnetic field and temperature, the following types of magnetic ordering are identified at various chromium layer thicknesses: ferromagnetic, antiferromagnetic, and canted ordering. A comparison of the experimental and calculated curves allowed us to determine the dependence of the bilinear (J{sub 1}) and biquadratic (J{sub 2}) exchange constants on chromium layer thickness t{sub Cr}. Weak oscillations at a period of about 18 Å are detected in the J{sub 1}(t{sub Cr}) dependence in the range 8–30 Å. The interlayer coupling oscillations in the system under study are assumed to be related to the RKKY exchange interaction mechanism via the conduction electrons of Cr.

  13. Fuel loading of PeBR for a long operation life on the lunar surface

    SciTech Connect (OSTI)

    Schriener, T. M.; El-Genk, M. S.

    2012-07-01

    The Pellet Bed Reactor (PeBR) power system could provide 99.3 kW e to a lunar outpost for 66 full power years and is designed for no single point failures. The core of this fast energy spectrum reactor consists of three sectors that are neutronically and thermally coupled, but hydraulically independent. Each sector has a separate Closed Brayton Cycle (CBC) loop for energy conversion and separate water heat-pipes radiator panels for heat rejection. He-Xe (40 g/mole) binary gas mixture serves as the reactor coolant and CBC working fluid. On the lunar surface, the emplaced PeBR below grade is loaded with spherical fuel pellets (1-cm in dia.). It is launched unfueled and the pellets are launched in separate subcritical canisters, one for each core sector. This paper numerically simulates the transient loading of a core sector with fuel pellets on the Moon. The simulation accounts for the dynamic interaction of the pellets during loading and calculates the axial and radial distributions of the volume porosity in the sector. The pellets pack randomly with a volume porosity of 0.39 - 0.41 throughout most of the sector, except near the walls the local porosity is higher. (authors)

  14. Effects of Cr and Ni on Interdiffusion and Reaction between U and Fe-Cr-Ni Alloys

    SciTech Connect (OSTI)

    K. Huang; Y. Park; L. Zhou; K.R. Coffey; Y.H. Sohn; B.H. Sencer; J. R. Kennedy

    2014-08-01

    Metallic U-alloy fuel cladded in steel has been examined for high temperature fast reactor technology wherein the fuel cladding chemical interaction is a challenge that requires a fundamental and quantitative understanding. In order to study the fundamental diffusional interactions between U with Fe and the alloying effect of Cr and Ni, solid-to-solid diffusion couples were assembled between pure U and Fe, Fe–15 wt.%Cr or Fe–15 wt.%Cr–15 wt.%Ni alloy, and annealed at high temperature ranging from 580 to 700 °C. The microstructures and concentration profiles that developed from the diffusion anneal were examined by scanning electron microscopy, and X-ray energy dispersive spectroscopy (XEDS), respectively. Thick U6Fe and thin UFe2 phases were observed to develop with solubilities: up to 2.5 at.% Ni in U6(Fe,Ni), up to 20 at.%Cr in U(Fe, Cr)2, and up to 7 at.%Cr and 14 at.% Ni in U(Fe, Cr, Ni)2. The interdiffusion and reactions in the U vs. Fe and U vs. Fe–Cr–Ni exhibited a similar temperature dependence, while the U vs. Fe–Cr diffusion couples, without the presence of Ni, yielded greater activation energy for the growth of intermetallic phases – lower growth rate at lower temperature but higher growth rate at higher temperature.

  15. High temperature crystal structures and superionic properties of SrCl{sub 2}, SrBr{sub 2}, BaCl{sub 2} and BaBr{sub 2}

    SciTech Connect (OSTI)

    Hull, Stephen; Norberg, Stefan T.; Ahmed, Istaq; Eriksson, Sten G.; Mohn, Chris E.

    2011-11-15

    The structural properties of the binary alkaline-earth halides SrCl{sub 2}, SrBr{sub 2}, BaCl{sub 2} and BaBr{sub 2} have been investigated from ambient temperature up to close to their melting points, using the neutron powder diffraction technique. Fluorite-structured SrCl{sub 2} undergoes a gradual transition to a superionic phase at 900-1100 K, characterised by an increasing concentration of anion Frenkel defects. At a temperature of 920(3) K, the tetragonal phase of SrBr{sub 2} undergoes a first-order transition to a cubic fluorite phase. This high temperature phase shows the presence of extensive disorder within the anion sublattice, which differs from that found in superionic SrCl{sub 2}. BaCl{sub 2} and BaBr{sub 2} both adopt the cotunnite crystal structure under ambient conditions. BaCl{sub 2} undergoes a first-order structural transition at 917(5) K to a disordered fluorite-structured phase. The relationship between the (disordered) crystal structures and the ionic conductivity behaviour is discussed and the influence of the size of the mobile anion on the superionic behaviour is explored. - Graphical abstract: Anomalous behaviour of the lattice expansion of SrCl{sub 2} at temperatures of {approx}1000 K is associated with the gradual transition to a superionic phase, whilst SrBr{sub 2} undergoes a first-order structural transition ({beta}{yields}{alpha}) to a fluorite-structured superionic phase at 920(3) K. Highlights: > Anomalous behaviour of the lattice expansion of SrCl{sub 2} occurs at temperatures {approx}1000 K. > Crystal structure of {beta}-SrBr{sub 2} is described in detail. > On heating, SrBr{sub 2} and BaCl{sub 2} transform to a fluorite-structured superionic phase. > Temperature dependence of the BaCl{sub 2} and BaBr{sub 2} structures is presented. > Nature of the superionic phases within the alkaline-earth halides is discussed.

  16. TI--CR--AL--O thin film resistors

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2000-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  17. Audit of Controls Over the ADP Support Services Contract, CR...

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

    Audit Report Number: CR-B-97-04 SUMMARY The Federal Acquisition Regulation requires the Department of Energy ... and best practices in other Federal agencies and the private sector. ...

  18. 9 Cr-- 1 Mo steel material for high temperature application

    DOE Patents [OSTI]

    Jablonski, Paul D; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-11-27

    One or more embodiments relates to a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The 9 Cr-1 Mo steel has a tempered martensite microstructure and is comprised of both large (0.5-3 .mu.m) primary titanium carbides and small (5-50 nm) secondary titanium carbides in a ratio of. from about 1:1.5 to about 1.5:1. The 9 Cr-1 Mo steel may be fabricated using exemplary austenizing, rapid cooling, and tempering steps without subsequent hot working requirements. The 9 Cr-1 Mo steel exhibits improvements in total mass gain, yield strength, and time-to-rupture over ASTM P91 and ASTM P92 at the temperature and time conditions examined.

  19. Infrared fluorescence studies of electronic-to-vibrational energy transfer in a Br2:NO system. Master's thesis

    SciTech Connect (OSTI)

    Hawks, M.R.

    1993-12-01

    Steady-state photolysis techniques were used to study electronic-to-vibrational energy transfer mechanisms from atomic bromine to nitric oxide. Molecular bromine was photodissociated by 488nm radiation to produce equal parts Br(2p(sub 1/2)) and Br(2p (sub 3/2)). Side fluorescence intensity from Br(2p (sub 1/2)) at 2.7 microns and from NO (v =1) and 2 around 5.3 microns measured as a function of bromine pressure and nitric oxide pressure. The branching ratio collisional transfer into the first and second states of NO was determined, and previously reported rates for quenching of NO by molecular bromine were verified. Nitric oxide, Bromine, E-V transfer, Infrared fluorescence, Photolysis.

  20. Enhanced magnetization at the Cr/MgO(001) interface

    SciTech Connect (OSTI)

    Leroy, M.-A.; Bataille, A. M. Ott, F.; Wang, Q.; Fitzsimmons, M. R.; Bertran, F.; Le Fèvre, P.; Taleb-Ibrahimi, A.; Vlad, A.; Coati, A.; Garreau, Y.; Hauet, T.; Andrieu, S.; Gatel, C.

    2015-12-21

    We report on the magnetization at the Cr/MgO interface, which we studied through two complementary techniques: angle-resolved photoemission spectroscopy and polarized neutron reflectivity. We experimentally observe an enhanced interface magnetization at the interface, yet with values much smaller than the ones reported so far by theoretical and experimental studies on Cr(001) surfaces. Our findings cast some doubts on the interpretations on previous works and could be useful in antiferromagnetic spin torque studies.

  1. Phase stability and elastic properties of Cr-V alloys

    SciTech Connect (OSTI)

    Gao, M. C.; Suzuki, Y.; Schweiger, H.; Do?an, .N.; Hawk, J.; Widom M.

    2013-02-20

    V is the only element in the periodic table that forms a complete solid solution with Cr and thus is particularly important in alloying strategy to ductilize Cr. This study combines first-principles density functional theory calculations and experiments to investigate the phase stability and elastic properties of CrV binary alloys. The cluster expansion study reveals the formation of various ordered compounds at low temperatures that were not previously known. These compounds become unstable due to the configurational entropy of bcc solid solution as the temperature is increased. The elastic constants of ordered and disordered compounds are calculated at both T = 0 K and finite temperatures. The overall trends in elastic properties are in agreement with measurements using the resonant ultrasound spectroscopy method. The calculations predict that addition of V to Cr decreases both the bulk modulus and the shear modulus, and enhances the Poissons ratio, in agreement with experiments. Decrease in the bulk modulus is correlated to decrease in the valence electron density and increase in the lattice constant. An enhanced Poissons ratio for bcc CrV alloys (compared to pure Cr) is associated with an increased density of states at the Fermi level. Furthermore, the difference charge density in the bonding region in the (110) slip plane is highest for pure Cr and decreases gradually as V is added. The present calculation also predicts a negative Cauchy pressure for pure Cr, and it becomes positive upon alloying with V. The intrinsic ductilizing effect from V may contribute, at least partially, to the experimentally observed ductilizing phenomenon in the literature.

  2. Molecular Characterization of Brown Carbon (BrC) Chromophores in Secondary Organic Aerosol Generated From Photo-Oxidation of Toluene

    SciTech Connect (OSTI)

    Lin, Peng; Liu, Jiumeng; Shilling, John E.; Kathmann, Shawn M.; Laskin, Julia; Laskin, Alexander

    2015-09-28

    Atmospheric Brown carbon (BrC) is a significant contributor to light absorption and climate forcing. However, little is known about a fundamental relationship between the chemical composition of BrC and its optical properties. In this work, light-absorbing secondary organic aerosol (SOA) was generated in the PNNL chamber from toluene photo-oxidation in the presence of NOx (Tol-SOA). Molecular structures of BrC components were examined using nanospray desorption electrospray ionization (nano-DESI) and liquid chromatography (LC) combined with UV/Vis spectroscopy and electrospray ionization (ESI) high-resolution mass spectrometry (HRMS). The chemical composition of BrC chromophores and the light absorption properties of toluene SOA (Tol-SOA) depend strongly on the initial NOx concentration. Specifically, Tol-SOA generated under high-NOx conditions (defined here as initial NOx/toluene of 5/1) appears yellow and mass absorption coefficient of the bulk sample (MACbulk@365nm = 0.78 m2 g-1) is nearly 80 fold higher than that measured for the Tol-SOA sample generated under low-NOx conditions (NOx/toluene < 1/300). Fifteen compounds, most of which are nitrophenols, are identified as major BrC chromophores responsible for the enhanced light absorption of Tol-SOA material produced in the presence of NOx. The integrated absorbance of these fifteen chromophores accounts for 40-60% of the total light absorbance by Tol-SOA at wavelengths between 300 nm and 500 nm. The combination of tandem LC-UV/Vis-ESI/HRMS measurements provides an analytical platform for predictive understanding of light absorption properties by BrC and their relationship to the structure of individual chromophores. General trends in the UV/vis absorption by plausible isomers of the BrC chromophores were evaluated using theoretical chemistry calculations. The molecular-level understanding of BrC chemistry is helpful for better understanding the evolution and behavior of light absorbing aerosols in the atmosphere.

  3. LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

    DOE Patents [OSTI]

    Ko, Suk M.

    1980-01-01

    This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

  4. X-ray-absorption study of CuBr at high pressure

    SciTech Connect (OSTI)

    Tranquada, J.M.; Ingalls, R.

    1986-09-15

    The x-ray-absorption spectrum of cuprous bromide has been measured as a function of pressure. The x-ray-absorption near-edge structure proved to be an excellent indicator of high-pressure phase transitions in this material. The normalized ''white-line'' peak heights at both the Cu and Br K-italic edges decreased on entering the tetragonal phase and increased in going to the NaCl structure. The zinc-blende to tetragonal phase transition took place over a very narrow pressure range centered at 46 +- 5 kbar. The transformation from the tetragonal to the NaCl structure, on the other hand, showed a broad mixed-phase region, suggesting a nucleation-and-growth mechanism for the transition. The mixed-phase region was centered at 75 +- 6 kbar. No evidence of a phase between the zinc-blende and tetragonal phases was observed, presumably because it does not exist. Analysis of the extended x-ray-absorption fine-structure (EXAFS) clearly showed that there is no change in coordination in going from the zinc-blende to the tetragonal phase although the nearest-neighbor distance increases slightly. A much larger increase in R-italic/sub 1/ occurs at the transition to the NaCl structure, where the coordination increases from 4 to 6. The mean-square deviation in the nearest-neighbor bond length, sigma/sub 1//sup 2/, appears to be a fairly smooth function of nearest-neighbor distance, decreasing (or increasing) as R-italic/sub 1/ decreases (or increases) more or less independent of structure. Evidence from the literature was presented to suggest that the zinc-blende to tetragonal transition in CuBr (and also CuCl) should occur by shear deformation.

  5. Influence of Cr on the nanoclusters formation and superferromagnetic behavior of Fe-Cr-Nb-B glassy alloys

    SciTech Connect (OSTI)

    Chiriac, H.; Whitmore, L.; Grigoras, M.; Ababei, G.; Stoian, G.; Lupu, N.

    2015-05-07

    High resolution imaging and electron diffraction confirm that in the as-quenched state the structure of Fe{sub 79.7−x}Cr{sub x}Nb{sub 0.3}B{sub 20} (x = 11–13 at. %) melt-spun ribbons is completely amorphous, independent of the Cr content. Energy-dispersive X-ray spectroscopy mapping emphasizes clearly the presence of Fe and Cr clusters varying from approximately 1 to 2–3 nm in size with the increase of Cr content from 11 to 13 at. %. The Fe and Cr atoms segregate the atomic scale to form nanometer sized clusters, influencing strongly the macroscopic magnetic behavior. The Curie temperature of the system, T{sub C}{sup system}, confirmed by the magnetic susceptibility versus temperature measurements, gives the strength of the magnetic interactions between clusters. The inter-cluster interactions are much stronger for lower contents of Cr, the microstructure is less uniform, and T{sub C}{sup system} increases from 290 K for 13 at. % Cr to 330 K for 11.5 at. % Cr. The whole system transforms to a ferromagnetic state through interactions between the clusters. Zero-field cooling and field cooling curves confirm the cluster behavior with a blocking temperature, T{sub b}, of about 250 K. Above T{sub b}, the ribbons behave as a superferromagnetic system, whilst below the blocking temperature a classical ferromagnetic behavior is observed.

  6. 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.

  7. Ultrafast dynamics of strong-field dissociative ionization ofCH2Br2 probed by femtosecond soft x-ray transient absorptionspectroscopy

    SciTech Connect (OSTI)

    Loh, Zhi-Heng; Leone, Stephen R.

    2008-01-15

    Femtosecond time-resolved soft x-ray transient absorption spectroscopy based on a high-order harmonic generation source is used to investigate the dissociative ionization of CH{sub 2}Br{sub 2} induced by 800 nm strong-field irradiation. At moderate peak intensities (2.0 x 10{sup 14} W/cm{sup 2}), strong-field ionization is accompanied by ultrafast C-Br bond dissociation, producing both neutral Br ({sup 2}P{sub 3/2}) and Br* ({sup 2}P{sub 1/2}) atoms together with the CH{sub 2}Br{sup +} fragment ion. The measured rise times for Br and Br* are 130 {+-} 22 fs and 74 {+-} 10 fs, respectively. The atomic bromine quantum state distribution shows that the Br/Br* population ratio is 8.1 {+-} 3.8 and that the Br {sup 2}P{sub 3/2} state is not aligned. The observed product distribution and the timescales of the photofragment appearances suggest that multiple field-dressed potential energy surfaces are involved in the dissociative ionization process. In addition, the transient absorption spectrum of CH{sub 2}Br{sub 2}{sup +} suggests that the alignment of the molecule relative to the polarization axis of the strong-field ionizing pulse determines the electronic symmetry of the resulting ion; alignment of the Br-Br, H-H, and C{sub 2} axis of the molecule along the polarization axis results in the production of the ion {tilde X}({sup 2}B{sub 2}), {tilde B}({sup 2}B{sub 1}) and {tilde C}({sup 2}A{sub 1}) states, respectively. At higher peak intensities (6.2 x 10{sup 14} W/cm{sup 2}), CH{sub 2}Br{sub 2}{sup +} undergoes sequential ionization to form the metastable CH{sub 2}Br{sub 2}{sup 2+} dication. These results demonstrate the potential of core-level probing with high-order harmonic transient absorption spectroscopy for studying ultrafast molecular dynamics.

  8. Evaluation of production samples of the scintillators LaBr3:Ce andLaCl3:Ce

    SciTech Connect (OSTI)

    Choong, Woon-Seng; Derenzo, Stephen E.; Moses, William W.

    2005-09-15

    We report on the evaluation of the performance of two recently developed scintillator materials, LaCl{sub 3}:Ce and LaBr{sub 3}:Ce, at the task of gamma ray spectroscopy. Their performance is compared to a standard scintillator used for gamma ray spectroscopy--a 25 mm diameter 25 mm tall cylinder of NaI:Tl. We measure the pulse height, energy resolution, and full-energy efficiency of production LaBr{sub 3}:Ce and LaCl{sub 3}:Ce scintillation crystals of different sizes and geometries for a variety of gamma-ray energies. Using production rather than specially selected crystals will establish whether immediate large-scale use is feasible. The crystal is excited by gamma rays from one of six isotopic sources ({sup 125}I, {sup 241}Am, {sup 57}Co, {sup 22}Na, {sup 137}Cs, and {sup 60}Co) placed 15 cm away from the scintillator. Our measurements show that both LaCl{sub 3} and LaBr{sub 3} outperform NaI:Tl in almost all cases. They outperform NaI:Tl at all energies for the photopeak fraction and counting rate measurements, and for energy resolution at higher energies (above 200 keV for LaCl{sub 3} and 75 keV for LaBr{sub 3}). The performance of production crystals is excellent and these scintillators should be considered for immediate use in systems where stopping power and energy resolution are crucial.

  9. Electrodeposition of zinc on glassy carbon from ZnCl/sub 2/ and ZnBr/sub 2/ electrolytes

    SciTech Connect (OSTI)

    McBreen, J.; Gannon, E.

    1983-08-01

    The initial stages of the electrocrystallization of zinc from 3M ZnCl/sub 2/ and 3M ZnBr/sub 2/ on glassy carbon has been investigated using cyclic voltametry, the potential step method, and scanning electron microscopy. Particular care was taken to ensure electrolyte purity and to eliminate resistance effects in the measurements. The nucleation overvoltage in 3M ZnCl/sub 2/ was about 17 and about 12 mV in 3M ZnBr/sub 2/. In 3M ZnCl/sub 2/, the current transients from the potential step measurements could be fitted to a simple model that assumes instantaneous nucleation followed by growth of three dimensional centers under kinetic control. A similar mechanism is operative for 3M ZnBr/sub 2/ at low overvoltages. At higher overvoltages, the current transient is governed by mixed kinetic and diffusion control and cannot be fitted to a simple model. The lower nucleation overvoltage and the faster kinetics in 3M ZnBr/sub 2/ is correlated with the lower stability constants for the zinc bromide complexes. Erroneous results are obtained when resistance effects are not accounted for.

  10. A XANES and EXAFS Study of Hydration and Ion Pairing in Ambient Aqueous MnBr[subscript 2] Solutions

    SciTech Connect (OSTI)

    Chen, Yongsheng; Fulton, John L.; Partenheimer, Walter

    2008-09-25

    Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopies were used to probe the first-shell coordination structure of Mn(II) in aqueous MnBr{sub 2} solutions at ambient conditions from very dilute to the near saturation limit. The Mn K-edge EXAFS spectra for 0.05 and 0.2 m solutions showed that there was no Br(-I) in the first shell, and that the Mn(II) was fully hydrated with six water molecules in an octahedral arrangement. In contrast, for 6 m solution, the coordination number of water was reduced to about 5, and an average of about one bromine atom was present in the first shell as a contact ion pair. The 1s {yields} 4p transition at 6545.5 eV confirmed the observation of Mn-Br contact ion pairs at high concentrations and the 1s {yields} 3d transition at 6539.5 eV showed that the first shell coordination symmetry remained octahedral even in the presence of Mn-Br ion pairs.

  11. Chromium Isotope Fractionation During Reduction of Cr(VI) Under Saturated Flow Conditions

    SciTech Connect (OSTI)

    Jamieson-Hanes, Julia H.; Gibson, Blair D.; Lindsay, Matthew B.J.; Kim, Yeongkyoo; Ptacek, Carol J.; Blowes, David W.

    2012-10-25

    Chromium isotopes are potentially useful indicators of Cr(VI) reduction reactions in groundwater flow systems; however, the influence of transport on Cr isotope fractionation has not been fully examined. Laboratory batch and column experiments were conducted to evaluate isotopic fractionation of Cr during Cr(VI) reduction under both static and controlled flow conditions. Organic carbon was used to reduce Cr(VI) in simulated groundwater containing 20 mg L{sup -1} Cr(VI) in both batch and column experiments. Isotope measurements were performed on dissolved Cr on samples from the batch experiments, and on effluent and profile samples from the column experiment. Analysis of the residual solid-phase materials by scanning electron microscopy (SEM) and by X-ray absorption near edge structure (XANES) spectroscopy confirmed association of Cr(III) with organic carbon in the column solids. Decreases in dissolved Cr(VI) concentrations were coupled with increases in {delta}{sup 53}Cr, indicating that Cr isotope enrichment occurred during reduction of Cr(VI). The {delta}{sup 53}Cr data from the column experiment was fit by linear regression yielding a fractionation factor ({alpha}) of 0.9979, whereas the batch experiments exhibited Rayleigh-type isotope fractionation ({alpha} = 0.9965). The linear characteristic of the column {delta}{sup 53}Cr data may reflect the contribution of transport on Cr isotope fractionation.

  12. Surface structure of ?-Cr2O3(0001) after activated oxygen exposure

    SciTech Connect (OSTI)

    Kaspar, Tiffany C.; Chamberlin, Sara E.; Chambers, Scott A.

    2013-09-13

    The surface structure of a-Cr2O3(0001) before and after exposure to activated oxygen from an ECR plasma source was investigated by x-ray photoelectron spectroscopy (XPS) and x-ray photoelectron diffraction (XPD). Epitaxial Cr2O3(0001) thin films were deposited on Al2O3(0001) substrates by oxygen-plasma-assisted molecular beam epitaxy (OPA-MBE). When cooled or annealed in vacuum, strong evidence for a Cr-Cr-O3- termination was obtained by comparing the Cr3+ XPD azimuthal scan to single scattering simulations. However, after plasma exposure, a high binding energy feature was observed in the Cr 2p XPS spectrum that possesses an ordered structure distinct from the underlying Cr3+ of Cr2O3, which remains Cr-Cr-O3-like. Investigation of this new surface structure with simulations of various candidate structures tentatively rules out CrO2-like configurations. The high binding energy feature likely arises from a higher oxidation state of Cr. One possibility is the oxidation of the surface layer of Cr to Cr6- with a double chromyl structure (O=Cr=O).

  13. Gamma-ray decay of levels in /sup 53/Cr

    SciTech Connect (OSTI)

    Dickens, J.K.; Larson, D.C.

    1987-11-01

    Gamma-ray decay of levels in the stable isotope /sup 53/Cr has been studied using /sup 53/Cr(n,n'..gamma..) reactions for incident neutron energies between threshold and 10 MeV. Of the 65 gamma rays or gamma-ray groups observed for neutron interactions with /sup 53/Cr, 50 have been placed or tentatively placed among 34 levels in /sup 53/Cr up to an excitation energy of 4.36 MeV. Deduced branching ratios are in reasonable agreement with previous measurements except for decay of the E/sub x/ = 1537-keV level. For the decay of the E/sub x/ = 1537-keV level we are unable to explain variations in the branching ratios of the transition gamma rays as a function of incident neutron energy within the framework of the presently known level structure of /sup 53/Cr and suggest the possibility of a second energy level at E/sub x/ = 1537 keV. 59 refs., 13 figs., 2 tabs.

  14. Ag/AgBr/g-C{sub 3}N{sub 4}: A highly efficient and stable composite photocatalyst for degradation of organic contaminants under visible light

    SciTech Connect (OSTI)

    Cao, Jing; Zhao, Yijie; Lin, Haili; Xu, Benyan; Chen, Shifu

    2013-10-15

    Graphical abstract: Ag/AgBr/g-C{sub 3}N{sub 4} composite photocatalysts displayed excellent photocatalytic activities on the degradation of methyl orange (MO) under visible light. The improved photocatalytic performance and stability of Ag/AgBr/g-C{sub 3}N{sub 4} originated from the synergetic effects of AgBr/g-C{sub 3}N{sub 4} interface and metallic Ag nanoparticles. O{sub 2}?, one of the reactive species, was responsible for the photodegradation of MO compared to H+ and OH. - Highlights: Novel Ag/AgBr/g-C{sub 3}N{sub 4} composite photocatalyst was reported. Ag/AgBr/g-C{sub 3}N{sub 4} had novel energy band combination between AgBr and g-C{sub 3}N{sub 4}. Synergetic effects of AgBr/g-C{sub 3}N{sub 4} interface and metallic Ag nanoparticles. Electron trapping role of metallic Ag dominated the stability of Ag/AgBr/g-C{sub 3}N{sub 4}. - Abstract: Novel Ag/AgBr/g-C{sub 3}N{sub 4} composite photocatalysts were constructed via depositionprecipitation method and extensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and UVvis diffuse reflectance spectroscopy (DRS). Under visible light (? > 420 nm), Ag/AgBr/g-C{sub 3}N{sub 4} composite photocatalysts displayed much higher photocatalytic activities than those of Ag/AgBr and g-C{sub 3}N{sub 4} for degradation of methyl orange (MO). 50% Ag/AgBr/g-C{sub 3}N{sub 4} presented the best photocatalytic performance, which was mainly attributed to the synergistic effects of AgBr/g-C{sub 3}N{sub 4} interface and the in situ metallic Ag nanoparticles for efficiently separating electronhole pairs. Furthermore, Ag/AgBr/g-C{sub 3}N{sub 4} remained good photocatalytic activity through 5 times of cycle experiments. Additionally, the radical scavengers experiment indicated that O{sub 2}{sup ?} was the main reactive species for the MO degradation under visible light.

  15. Synthesis and photocatalytic performance of an efficient Ag@AgBr/K{sub 2}Ti{sub 4}O{sub 9} composite photocatalyst under visible light

    SciTech Connect (OSTI)

    Liang, Yinghua; Lin, Shuanglong; Liu, Li; Hu, Jinshan; Cui, Wenquan

    2014-08-15

    Highlights: The plasmatic Ag@AgBr sensitized K{sub 2}Ti{sub 4}O{sub 9} composite photocatalysts. Ag@AgBr greatly increased visible light absorption for K{sub 2}Ti{sub 4}O{sub 9}. The plamonic photocatalysts exhibited enhanced activity for the degradation of RhB. - Abstract: Ag@AgBr nanoparticle-sensitized K{sub 2}Ti{sub 4}O{sub 9} composite photocatalysts (Ag@AgBr/K{sub 2}Ti{sub 4}O{sub 9}) were prepared by a facile precipitationphotoreduction method. The photocatalytic activities of the Ag@AgBr/K{sub 2}Ti{sub 4}O{sub 9} nanocomposites were evaluated for photocatalytic degradation of (RhB) under visible light irradiation. The composites exhibited excellent visible light absorption, which was attributable to the surface plasmon effect of Ag nanoparticles. The Ag@AgBr was uniformly scattered on the surface of K{sub 2}Ti{sub 4}O{sub 9} and possessed sizes in the range of 2050 nm. The loading amount of Ag@AgBr was also studied, and was found to influence the absorption spectra of the resulting composites. Approximately 95.9% of RhB was degraded by Ag@AgBr (20 wt.%)/K{sub 2}Ti{sub 4}O{sub 9} after irradiation for 1 h. The stability of the material was also investigated by performing consecutive runs. Additionally, studies performed using radical scavengers indicated that O{sub 2}{sup ?} and Br{sup 0} acted as the main reactive species. Based on the experimental results, a photocatalytic mechanism for organics degradation over Ag@AgBr/K{sub 2}Ti{sub 4}O{sub 9} photocatalysts was proposed.

  16. Grain boundary depletion and migration during selective oxidation of Cr in a Ni-5Cr binary alloy exposed to high-temperature hydrogenated water

    SciTech Connect (OSTI)

    Schreiber, Daniel K.; Olszta, Matthew J.; Bruemmer, Stephen M.

    2014-10-01

    High-resolution microscopy of a high-purity Ni-5Cr alloy exposed to 360C hydrogenated water reveals intergranular selective oxidation of Cr accompanied by local Cr depletion and diffusion-induced grain boundary migration (DIGM). The corrosion-product oxide consists of a porous, interconnected network of Cr2O3 platelets with no further O ingress into the metal ahead. Extensive grain boundary depletion of Cr (to <0.05at.%) is observed typically 20100 nm wide as a result of DIGM and reaching depths of many micrometers beyond the oxidation front.

  17. Room-temperature ferromagnetism in Cr-doped Si achieved by controlling atomic structure, Cr concentration, and carrier densities: A first-principles study

    SciTech Connect (OSTI)

    Wei, Xin-Yuan; Yang, Zhong-Qin; Zhu, Yan; Li, Yun

    2015-04-28

    By using first-principles calculations, we investigated how to achieve a strong ferromagnetism in Cr-doped Si by controlling the atomic structure and Cr concentration as well as carrier densities. We found that the configuration in which the Cr atom occupies the tetrahedral interstitial site can exist stably and the Cr atom has a large magnetic moment. Using this doping configuration, room-temperature ferromagnetism can be achieved in both n-type and p-type Si by tuning Cr concentration and carrier densities. The results indicate that the carrier density plays a crucial role in realizing strong ferromagnetism in diluted magnetic semiconductors.

  18. Importance of Doping and Frustration in Itinerant Fe-doped Cr2Al

    SciTech Connect (OSTI)

    Susner, Michael A; Parker, David S; Safa-Sefat, Athena

    2015-01-01

    We have performed an experimental and theoretical study comparing the effects of Fe-doping of Cr2Al, an antiferromagnet with a N el temperature of 670 K, with known results on Fe-doping of antiferromagnetic bcc Cr. (Cr1-xFex)2Al materials are found to exhibit a rapid suppression of antiferromagnetic order with the presence of Fe, decreasing TN to 170 K for x=0.10. Antiferromagnetic behavior disappears entirely at x 0.125 after which point increasing paramagnetic behavior is exhibited. This is unlike the effects of Fe doping of bcc antiferromagnetic Cr, in which TN gradually decreases followed by the appearance of a ferromagnetic state. Theoretical calculations explain that the Cr2Al-Fe suppression of magnetic order originates from two effects: the first is band narrowing caused by doping of additional electrons from Fe substitution that weakens itinerant magnetism; the second is magnetic frustration of the Cr itinerant moments in Fe-substituted Cr2Al. In pure-phase Cr2Al, the Cr moments have an antiparallel alignment; however, these are destroyed through Fe substitution and the preference of Fe for parallel alignment with Cr. This is unlike bulk Fe-doped Cr alloys in which the Fe anti-aligns with the Cr atoms, and speaks to the importance of the Al atoms in the magnetic structure of Cr2Al and Fe-doped Cr2Al.

  19. Importance of Doping and Frustration in Itinerant Fe-doped Cr2Al

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

    Susner, Michael A; Parker, David S; Safa-Sefat, Athena

    2015-01-01

    We have performed an experimental and theoretical study comparing the effects of Fe-doping of Cr2Al, an antiferromagnet with a N el temperature of 670 K, with known results on Fe-doping of antiferromagnetic bcc Cr. (Cr1-xFex)2Al materials are found to exhibit a rapid suppression of antiferromagnetic order with the presence of Fe, decreasing TN to 170 K for x=0.10. Antiferromagnetic behavior disappears entirely at x 0.125 after which point increasing paramagnetic behavior is exhibited. This is unlike the effects of Fe doping of bcc antiferromagnetic Cr, in which TN gradually decreases followed by the appearance of a ferromagnetic state. Theoretical calculationsmore » explain that the Cr2Al-Fe suppression of magnetic order originates from two effects: the first is band narrowing caused by doping of additional electrons from Fe substitution that weakens itinerant magnetism; the second is magnetic frustration of the Cr itinerant moments in Fe-substituted Cr2Al. In pure-phase Cr2Al, the Cr moments have an antiparallel alignment; however, these are destroyed through Fe substitution and the preference of Fe for parallel alignment with Cr. This is unlike bulk Fe-doped Cr alloys in which the Fe anti-aligns with the Cr atoms, and speaks to the importance of the Al atoms in the magnetic structure of Cr2Al and Fe-doped Cr2Al.« less

  20. Metastable bcc phase formation in the Nb-Cr system

    SciTech Connect (OSTI)

    Thoma, D.J.; Schwarz, R.B.; Perepezko, J.H.; Plantz, D.H.

    1993-08-01

    Extended metastable bcc solid solutions of Nb-Xat.%Cr (X = 35, 50, 57, 77, 82, and 94) were synthesized by two-anvil splat-quenching. In addition, bcc (Nb-67at.%Cr) was prepared by mechanically alloying mixtures of niobium and chromium powders. The lattice parameters were measured by X-ray diffraction and the Young`s moduli were measured by low-load microindentation. The composition dependence of the lattice parameters and elastic moduli show a positive deviation with respect to a rule of mixtures. During continuous heating at 15C/min., the metastable precursor bcc phases decomposed at temperatures above 750C to uniformly refined microstructures.

  1. Photoluminescence characteristics of polariton condensation in a CuBr microcavity

    SciTech Connect (OSTI)

    Nakayama, Masaaki Murakami, Katsuya; Furukawa, Yoshiaki; Kim, DaeGwi

    2014-07-14

    We have investigated the photoluminescence (PL) properties of a CuBr microcavity at 10?K, including the temporal profiles, from the viewpoint of cavity-polariton condensation. The excitation energy density dependence of the PL intensity (band width) of the lower polariton branch at an in-plane wave vector of k{sub //}?=?0 exhibits a threshold-like increase (decrease). A large blueshift in the PL energy of ?10?meV caused by the cavity-polariton renormalization is correlated with the excitation energy density dependence of the PL intensity. The estimated density of photogenerated electron-hole pairs at the threshold is two orders lower than the Mott transition density. These results consistently demonstrate the occurrence of cavity-polariton condensation. In addition, we found that the PL rise and decay times are shortened dramatically by the cavity-polariton condensation, which reflects the bosonic final state stimulation in the relaxation process and the intrinsic cavity-polariton lifetime in the decay process.

  2. Direct molecular diffusion and micro-mixing for rapid dewatering of LiBr solution

    SciTech Connect (OSTI)

    Bigham, S; Isfahani, RN; Moghaddam, S

    2014-03-01

    A slow molecular diffusion rate often limits the desorption process of an absorbate molecule from a liquid absorbent. To enhance the desorption rate, the absorbent is often boiled to increase the liquid vapor interfacial area. However, the growth of bubbles generated during the nucleate boiling process still remains mass-diffusion limited. Here, it is shown that a desorption rate higher than that of boiling can be achieved, if the vapor absorbent interface is continuously replenished with the absorbate-rich solution to limit the concentration boundary layer growth. The study is conducted in a LiBr-water-solution, in which the water molecules' diffusion rate is quite slow. The manipulation of the vapor solution interface concentration distribution is enabled by the mechanical confinement of the solution flow within microchannels, using a hydrophobic vapor-venting membrane and the implementation of microstructures on the flow channel's bottom wall. The microstructures stretch and fold the laminar streamlines within the solution film and produce vortices. The vortices continuously replace the concentrated solution at the vapor solution interface with the water-rich solution brought from the bottom and middle of the flow channel. The physics of the process is described using a combination of experimental and numerical studies. Published by Elsevier Ltd.

  3. The corrosion phenomena in the coin cell BR2325 of the ``superstoichiometric fluorocarbon-lithium'' system

    SciTech Connect (OSTI)

    Mitkin, V.N.; Galkin, P.S.; Denisova, T.N.

    1998-07-01

    It was noted at the earlier study and at the longer observations of the novel various types of superstoichiometric fluorocarbon materials CF{sub 1+x}, where x = 0.1--0.33 (FCM) and their behavior, that despite of their known hygroscopity during a storage of samples in laboratory and technological utensils nevertheless occurs an appreciable sorption of atmospheric moisture. The color of samples does not change but sometimes there appears a smell of hydrogen fluoride and even corrosion of glasswares at a long storage. On the basis of these facts was assumed that at a long storage the slow reactions of HF producing with a sorption moisture can proceed. This phenomena is necessary to take into account for successful manufacturing of long life lithium cells based on superstoichiometric fluorocarbon composite cathodes (FCC). The chemistry of such slow hydrolytic process and especially of processes which can proceed at manufacturing of FCC earlier was not investigated also of any data in the literature in this occasion is not present. Just for this reason the authors undertook a study of the corrosion phenomena which can proceed in industrial sources of a current at a long storage under influence of slow hydrolysis of C-F bonds by moisture. The goal of the study was to search long term damages in the slightly wet FCM and based on these materials cathodic composites for fluorocarbon-lithium cells. As a model for corrosion process investigation they have chosen a standard coin lithium battery of a type BR2325.

  4. Viscosity and density of aqueous solutions of LiBr, LiCl, ZnBr[sub 2], CaCl[sub 2], and LiNO[sub 3]; 1: Single salt solutions

    SciTech Connect (OSTI)

    Wimby, J.M.; Berntsson, T.S. . Dept. of Heat and Power Technology)

    1994-01-01

    New experimental data for the viscosity and density of the binary systems lithium chloride + water, lithium bromide + water, calcium chloride + water, lithium nitrate + water, and zinc bromide + water are presented. Densities are presented in tabular form and as 10-parameter correlations, while kinematic and dynamic viscosities are presented in tabular form. Data are presented in the concentration range from intermediate dilution to close to room temperature crystallization concentration. The temperature ranges are 20--70 C for density and 25--90 C for viscosity. When available, literature data are compared with the new data, and some disagreement is found. New thermogravimetric curves are presented for the dehydration of CaCl[sub 2], ZnBr[sub 2], and LiBr in order to enable evaluation of drying as a composition determination technique.

  5. CR-39 track etching and blow-up method

    DOE Patents [OSTI]

    Hankins, Dale E. (Livermore, CA)

    1987-01-01

    This invention is a method of etching tracks in CR-39 foil to obtain uniformly sized tracks. The invention comprises a step of electrochemically etching the foil at a low frequency and a "blow-up" step of electrochemically etching the foil at a high frequency.

  6. Shell model description of band structure in 48Cr

    SciTech Connect (OSTI)

    Vargas, Carlos E.; Velazquez, Victor M.

    2007-02-12

    The band structure for normal and abnormal parity bands in 48Cr are described using the m-scheme shell model. In addition to full fp-shell, two particles in the 1d3/2 orbital are allowed in order to describe intruder states. The interaction includes fp-, sd- and mixed matrix elements.

  7. Audit Report: CR-FS-99-01

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

    MANAGEMENT REPORT AUDIT OF THE DEPARTMENT OF ENERGY'S CONSOLIDATED FINANCIAL STATEMENTS FOR FISCAL YEAR 1998 Report Number: CR-FS-99-01 Capital Regional Audit Office Date of Issue: June 15, 1999 Germantown, MD 20874 MANAGEMENT REPORT AUDIT OF THE DEPARTMENT OF ENERGY'S CONSOLIDATED FINANCIAL STATEMENTS FOR FISCAL YEAR 1998 TABLE OF CONTENTS Page SUMMARY.................................................................................. 1 PART I - APPROACH AND

  8. Magnetization reversal in TmCrO{sub 3}

    SciTech Connect (OSTI)

    Yoshii, Kenji

    2012-11-15

    Highlights: ► We observed two magnetization reversals in TmCrO{sub 3}. ► The reversal at 28 K is attributed to antiparallel coupling between Cr{sup 3+} and Tm{sup 3+}. ► The other reversal originates from spin reorientation. ► Magnetocaloric effect is observed at the spin reorientation temperature. ► Characteristic magnetization switching is demonstrated. -- Abstract: The perovskite chromite TmCrO{sub 3} shows magnetization reversal at two temperatures. The reversal at ∼28 K is attributed to the antiparallel coupling between Tm{sup 3+} and Cr{sup 3+} moments, while that at the lower temperature (∼6–7 K) is rooted in a rotation of the magnetic moments. Magnetocaloric measurements offer a relatively large entropy change (∼4–5 J kg{sup −1} K{sup −1}) at the lower temperature. The reversal at ∼28 K is accompanied by a sign change of an exchange-bias-like field. The absence of the training effect suggests that this behavior is rooted in unidirectional magnetic anisotropy. The existence of the two magnetization reversals offers the characteristic switching of magnetization. For example, the magnetization is flipped without changing the direction of the applied magnetic field.

  9. Cs{sub 3}Zr{sub 6}Br{sub 15}Z (Z = C, B): A stuffed rhombohedral perovskite structure of linked clusters

    SciTech Connect (OSTI)

    Qi, Ru-Yi; Corbett, J.D.

    1995-03-29

    The isostructural title compounds are synthesized in good yields form reactions of Zr, ZrBr{sub 4}, CsBr, and Z in sealed Ta tubing for {approximately}3 weeks at 850 {degrees}C. Their single-crystal data refinements established the products as Cs{sub 3.02(7)-}Zr{sub 6}Br{sub 14}C and Cs{sub 3.39(5)}Zr{sub 6}br{sub 15}B (R3c, Z = 6, a = 13.1031 (6), 13.116(1) {angstrom}, c = 35.800(3), 35.980(6) {angstrom}, R(F)/R{sub w} = 5.4/5.9, 5.4/4.4%, respectively). The structure is derived form a three-dimensional [Zr{sub 6}(Z)Br{sub 12}]Br{sub 6/2} network of four-rings (as in ReO{sub 6/2}) twisted into a rhombohedral perovskite analogous to VF{sub 3}. The three necessary Cs{sup +} cations are fractionally distributed over five sites that are far from optimal or common, with either eight asymmetric or only three close bromide neighbors. Refinement of a third Cs{sub 3.18(5)}Zr{sub 6}Br{sub 15}C structure at {minus}50 {degrees}C gave the same result with somewhat smaller positional distributions of the atoms.

  10. Periodicity, Electronic Structures, and Bonding of Gold Tetrahalides [AuX4](-) (X = F, CI, Br, I, At, Uus)

    SciTech Connect (OSTI)

    Li, Wan-Lu; Li, Yong; Xu, Congqiao; Wang, Xue B.; Vorpagel, Erich R.; Li, Jun

    2015-12-07

    Systematic theoretical and experimental investigations have been performed to understand the periodicity and electronic structures of trivalent-gold halides using gold tetrahalides [AuX4]⁻ anions (X = F, Cl, Br, I, At, Uus). The [AuX4]⁻ (X = Cl, Br, I) anions were produced in gas phase and their negative-ion photoelectron spectra were obtained, which exhibited rich and well-resolved spectral peaks. We calculated the adiabatic as well as vertical electron detachment energies using density functional methods with scalar and spin-orbit coupling relativistic effects. The simulated photoelectron spectra based on these calculations are in good agreement with the experimental spectra. Our results show that the trivalent Au(III) oxidation state becomes progressively less stable while Au(I) is preferred when the halides become heavier along the Period Table. This trend reveals that the oxidation state of metals in complexes can be manipulated through ligand design

  11. Comparison of CsBr and KBr coated Cu photocathodes: Effects of laser irradiation and work function changes

    SciTech Connect (OSTI)

    He, Weidong; VilayurGanapathy, Subramanian; Joly, Alan G.; Droubay, Timothy C.; Chambers, Scott A.; Maldonado, Juan R.; Hess, Wayne P.

    2013-02-20

    Thin films (7 nm layers) of CsBr and KBr were deposited on Cu(100) to investigate photoemission properties of these potential photocathode materials. After thin film deposition and prolonged laser ultraviolet (UV) irradiation (266 nm picosecond laser) photoemission quantum efficiency increases by factors of 26 and 77 for KBr/Cu(100) and CsBr/Cu(100) photocathodes, respectively. Immediately following thin film deposition, a decrease in work function is observed, compared to bare Cu, in both cases. Quantum efficiency enhancements are attributed to the decrease in photocathode work function, due to the deposition of alkali halide thin films, and photo-induced processes, that introduce defect states into the alkali halide bandgap, induced by UV laser irradiation. It is possible that alkali metal formation occurs during UV irradiation and that this further contributes to photoemission enhancement. Our results suggest that KBr, a relatively stable alkali-halide, has potential for photocathode applications.

  12. Steady-State Thermal-Hydraulics Analyses for the Conversion of the BR2 Reactor to LEU

    SciTech Connect (OSTI)

    Licht, J. R.; Bergeron, A.; Dionne, B.; Van den Branden, G.; Kalcheva, S.; Sikik, E.; Koonen, E.

    2015-12-01

    BR2 is a research reactor used for radioisotope production and materials testing. It’s a tank-in-pool type reactor cooled by light water and moderated by beryllium and light water (Figure 1). The reactor core consists of a beryllium moderator forming a matrix of 79 hexagonal prisms in a hyperboloid configuration; each having a central bore that can contain a variety of different components such as a fuel assembly, a control or regulating rod, an experimental device, or a beryllium or aluminum plug. Based on a series of tests, the BR2 operation is currently limited to a maximum allowable heat flux of 470 W/cm2 to ensure fuel plate integrity during steady-state operation and after a loss-of-flow/loss-of-pressure accident.

  13. Palladium-catalyzed Br/D exchange of arenes: Selective deuterium incorporation with versatile functional group tolerance and high efficiency

    SciTech Connect (OSTI)

    Zhang, Honghai -Hai; Bonnesen, Peter V.; Hong, Kunlun

    2015-07-13

    There is a facile method for introducing one or more deuterium atoms onto an aromatic nucleus via Br/D exchange with high functional group tolerance and high incorporation efficiency is disclosed. Deuterium-labeled aryl chlorides and aryl borates which could be used as substrates in cross-coupling reactions to construct more complicated deuterium-labeled compounds can also be synthesized by this method.

  14. Palladium-catalyzed Br/D exchange of arenes: Selective deuterium incorporation with versatile functional group tolerance and high efficiency

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

    Zhang, Honghai -Hai; Bonnesen, Peter V.; Hong, Kunlun

    2015-01-01

    There is a facile method for introducing one or more deuterium atoms onto an aromatic nucleus via Br/D exchange with high functional group tolerance and high incorporation efficiency is disclosed. Deuterium-labeled aryl chlorides and aryl borates which could be used as substrates in cross-coupling reactions to construct more complicated deuterium-labeled compounds can also be synthesized by this method.

  15. Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs2CuBr4

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

    Zvyagin, S. A.; Ozerov, M.; Kamenskyi, D.; Wosnitza, J.; Krzystek, J.; Yoshizawa, D.; Hagiwara, M.; Hu, Rongwei; Ryu, Hyejin; Petrovic, C.; et al

    2015-11-27

    We present on high- field electron spin resonance (ESR) studies of magnetic excitations in the spin- 1/2 triangular-lattice antiferromagnet Cs2CuBr4. 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 Cs2CuBr4 [Zvyagin et al:, Phys. Rev. Lett. 112, 077206 (2014)], is present well above TN. Noticeably, the transition into the long-range magnetically ordered phase does not significantly affect the size of the gap, suggesting that even below TN the high-energy spin dynamicsmore » in Cs2CuBr4 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.« less

  16. Pressure dependence of the magnetic order in CrAs: A neutron...

    Office of Scientific and Technical Information (OSTI)

    Pressure dependence of the magnetic order in CrAs: A neutron diffraction investigation Citation Details In-Document Search Title: Pressure dependence of the magnetic order in CrAs:...

  17. Uniform Corrosion of model FeCrAl Alloys in LWR Coolants (Conference...

    Office of Scientific and Technical Information (OSTI)

    Conference: Uniform Corrosion of model FeCrAl Alloys in LWR Coolants Citation Details In-Document Search Title: Uniform Corrosion of model FeCrAl Alloys in LWR Coolants Authors: ...

  18. Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized...

    Office of Scientific and Technical Information (OSTI)

    Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter deposition Title: Solid-solution CrCoCuFeNi high-entropy alloy thin films synthesized by sputter ...

  19. Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system...

    Office of Scientific and Technical Information (OSTI)

    Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system Title: Ti3CrCu4: A possible ... Country of Publication: United States Language: English Word Cloud More Like This Free ...

  20. Audit Report: CR-B-96-01 | Department of Energy

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

    Audit Report: CR-B-96-01 May 24, 1996 The Federal Energy Regulatory Commission Leased Warehouse Space PDF icon Audit Report: CR-B-96-01 More Documents & Publications Semiannual ...

  1. Audit Report: CR-FS-96-03 | Department of Energy

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

    Audit Report: CR-FS-96-03 April 15, 1996 Report on Matters Identified at Strategic Petroleum Reserve During Audit of Statement of Financial Position Audit Report: CR-FS-96-03 ...

  2. Audit Report: CR-B-95-06 | Department of Energy

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

    5-06 Audit Report: CR-B-95-06 June 30, 1995 Audit of Department of Energy Support Service Contracting PDF icon Audit Report: CR-B-95-06 More Documents & Publications Audit Report: ...

  3. Audit Report: CR-B-97-02 | Department of Energy

    Office of Environmental Management (EM)

    2 Audit Report: CR-B-97-02 April 4, 1997 Audit of Department of Energy's Contractor Salary Increase Funds Audit Report: CR-B-97-02 More Documents & Publications Inspection Report:...

  4. Audit Report: CR-FS-97-02 | Department of Energy

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

    FS-97-02 Audit Report: CR-FS-97-02 May 1, 1997 Audit of the Department of Energy's Consolidated Financial Statements for Fiscal Year 1996 Audit Report: CR-FS-97-02 More Documents &...

  5. Audit Report: CR-B-01-01 | Department of Energy

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

    Audit Report: CR-B-01-01 May 9, 2001 Issues Regarding Fee Structure for Three Environmental Management Contracts PDF icon Audit Report: CR-B-01-01 More Documents & Publications ...

  6. Technology Implimentation Plan - ATF FeCrAl Cladding for LWR Application

    SciTech Connect (OSTI)

    Snead, Mary A.; Snead, Lance; Terrani, Kurt A.; Field, Kevin G.; Worrall, Andrew; Robb, Kevin R.; Yamamoto, Yukinori; Powers, Jeffrey J.; Dryepondt, Sebastien N.; Pint, Bruce A.; Hu, Xunxiang

    2015-06-01

    Technology implimentation plan for FeCrAl development under the FCRD Advanced Fuel program. The document describes the activities required to get FeCrAl clad ready for LTR testing

  7. Audit Report: CR-B-95-03 | Department of Energy

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

    Audit Report: CR-B-95-03 February 6, 1995 Audit of the Department of Energy's Security Police Officer Training PDF icon Audit Report: CR-B-95-03 More Documents & Publications Type...

  8. Radiation effects on interface reactions of U/Fe, U/(Fe+Cr), and U/(Fe+Cr+Ni)

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

    Shao, Lin; Chen, Di; Wei, Chaochen; Martin, Michael S.; Wang, Xuemei; Park, Youngjoo; Dein, Ed; Coffey, Kevin R.; Sohn, Yongho; Sencer, Bulent H.; et al

    2014-10-01

    We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 C or 550 C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe++ ion irradiation. The Fe++ ion penetration depth is sufficient to reachmore »the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe++ ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.« less

  9. Non-classical nuclei and growth kinetics of Cr precipitates in FeCr alloys during ageing

    SciTech Connect (OSTI)

    Li, Yulan; Hu, Shenyang Y.; Zhang, Lei; Sun, Xin

    2014-01-10

    In this manuscript, we quantitatively calculated the thermodynamic properties of critical nuclei of Cr precipitates in FeCr alloys. The concentration profiles of the critical nuclei and nucleation energy barriers were predicted by the constrained shrinking dimer dynamics (CSDD) method. It is found that Cr concentration distribution in the critical nuclei strongly depend on the overall Cr concentration as well as temperature. The critical nuclei are non-classical because the concentration in the nuclei is smaller than the thermodynamic equilibrium value. These results are in agreement with atomic probe observation. The growth kinetics of both classical and non-classical nuclei was investigated by the phase field approach. The simulations of critical nucleus evolution showed a number of interesting phenomena: 1) a critical classical nucleus first shrinks toward its non-classical nucleus and then grows; 2) a non-classical nucleus has much slower growth kinetics at its earlier growth stage compared to the diffusion-controlled growth kinetics. 3) a critical classical nucleus grows faster at the earlier growth stage than the non-classical nucleus. All of these results demonstrate that it is critical to introduce the correct critical nuclei in order to correctly capture the kinetics of precipitation.

  10. Radiation effects on interface reactions of U/Fe, U/(Fe+Cr), and U/(Fe+Cr+Ni)

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

    Shao, Lin; Chen, Di; Wei, Chaochen; Martin, Michael S.; Wang, Xuemei; Park, Youngjoo; Dein, Ed; Coffey, Kevin R.; Sohn, Yongho; Sencer, Bulent H.; et al

    2014-10-01

    We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 C or 550 C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe++ ion irradiation. The Fe++ ion penetration depth is sufficient to reachmore » the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe++ ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.« less

  11. Radiation effects on interface reactions of U/Fe, U/(Fe+Cr), and U/(Fe+Cr+Ni)

    SciTech Connect (OSTI)

    Shao, Lin; Chen, Di; Wei, Chaochen; Martin, Michael S.; Wang, Xuemei; Park, Youngjoo; Dein, Ed; Coffey, Kevin R.; Sohn, Yongho; Sencer, Bulent H.; Rory Kennedy, J.

    2014-10-01

    We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 C or 550 C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe++ ion irradiation. The Fe++ ion penetration depth is sufficient to reach the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe++ ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.

  12. Surface half-metallicity of CrS thin films and perfect spin filtering and spin diode effects of CrS/ZnSe heterostructure

    SciTech Connect (OSTI)

    Gao, G. Y. Yao, K. L.

    2014-11-03

    Recently, ferromagnetic zinc-blende Mn{sub 1−x}Cr{sub x}S thin films (above x = 0.5) were fabricated experimentally on ZnSe substrate, which confirmed the previous theoretical prediction of half-metallic ferromagnetism in zinc-blende CrS. Here, we theoretically reveal that both Cr- and S-terminated (001) surfaces of the CrS thin films retain the half-metallicity. The CrS/ZnSe(001) heterogeneous junction exhibits excellent spin filtering and spin diode effects, which are explained by the calculated band structure and transmission spectra. The perfect spin transport properties indicate the potential applications of half-metallic CrS in spintronic devices. All computational results are obtained by using the density functional theory combined with nonequilibrium Green's function.

  13. Transport signatures of quantum critically in Cr at high pressure.

    SciTech Connect (OSTI)

    Jaramillo, R.; Feng, Y.; Wang, J.; Rosenbaum, T. F.

    2010-08-03

    The elemental antiferromagnet Cr at high pressure presents a new type of naked quantum critical point that is free of disorder and symmetry-breaking fields. Here we measure magnetotransport in fine detail around the critical pressure, P{sub c} {approx} 10 GPa, in a diamond anvil cell and reveal the role of quantum critical fluctuations at the phase transition. As the magnetism disappears and T {yields} 0, the magntotransport scaling converges to a non-mean-field form that illustrates the reconstruction of the magnetic Fermi surface, and is distinct from the critical scaling measured in chemically disordered Cr:V under pressure. The breakdown of itinerant antiferromagnetism only comes clearly into view in the clean limit, establishing disorder as a relevant variable at a quantum phase transition.

  14. Cr{sub 2}Nb-based alloy development

    SciTech Connect (OSTI)

    Liu, C.T.; Horton, J.A.; Carmichael, C.A.

    1996-05-01

    This paper summarizes recent progress in developing Cr{sub 2}Nb/Cr(Nb) alloys for structural use in advanced fossil energy conversion systems. Alloy additions were added to control the microstructure and mechanical properties. Two beneficial elements have been identified among all alloying additions added to the alloys. One element is effective in refining the coarse eutectic structure and thus substantially improves the compressive strength and ductility of the alloys. The other element enhances oxidation resistance without sacrificing the ductility. The tensile properties are sensitive to cast defects, which can not be effectively reduced by HIPping at 1450-1580{degrees}C and/or directionally solidifying via a floating zone remelting method.

  15. Cr/sup 3 +/-doped colquiriite solid state laser material

    DOE Patents [OSTI]

    Payne, S.A.; Chase, L.L.; Newkirk, H.W.; Krupke, W.F.

    1988-03-31

    Chromium doped colquiriite, LiCaAlF/sub 6/:Cr/sup 3 +/, is useful as a tunable laser crystal that has a high intrinsic slope efficiency, comparable to or exceeding that of alexandrite, the current leading performer of vibronic sideband Cr/sup 3 +/ lasers. The laser output is tunable from at least 720 nm to 840 nm with a measured slope efficiency of about 60% in a Kr laser pumped laser configuration. The intrinsic slope efficiency (in the limit of large output coupling) may approach the quantum defect limited value of 83%. The high slope efficiency implies that excited state absorption (ESA) is negligible. The potential for efficiency and the tuning range of this material satisfy the requirements for a pump laser for a high density storage medium incorporating Nd/sup 3 +/ or Tm/sup 3 +/ for use in a multimegajoule single shot fusion research facility. 4 figs.

  16. Cr.sup.3+ -doped colquiriite solid state laser material

    DOE Patents [OSTI]

    Payne, Stephen A.; Chase, Lloyd L.; Newkirk, Herbert W.; Krupke, William F.

    1989-01-01

    Chromium doped colquiriite, LiCaAlF.sub.6 :Cr.sup.3+, is useful as a tunable laser crystal that has a high intrinsic slope efficiency, comparable to or exceeding that of alexandrite, the current leading performer of vibronic sideband Cr.sup.3+ lasers. The laser output is tunable from at least 720 nm to 840 nm with a measured slop efficiency of about 60% in a Kr laser pumped laser configuration. The intrinsic slope efficiency (in the limit of large output coupling) may approach the quantum defect limited value of 83%. The high slope efficiency implies that excited state absorption (ESA) is negligible. The potential for efficiency and the tuning range of this material satisfy the requirements for a pump laser for a high density storage medium incorporating Nd.sup.3+ or Tm.sup.3+ for use in a multimegajoule single shot fusion research facility.

  17. SF6432-CR (02-01-13) Cost Reimbursement

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

    Department Release Date: 11/17/15 Page 1 of 25 Printed copies of this document are uncontrolled. Retrieve latest version electronically. SANDIA CORPORATION SF 6432-CR (11/2015) SECTION II STANDARD TERMS AND CONDITIONS FOR COST-REIMBURSEMENT CONTRACTS THE FOLLOWING CLAUSES APPLY TO THIS CONTRACT AS INDICATED UNLESS SPECIFICALLY DELETED, OR EXCEPT TO THE EXTENT THEY ARE SPECIFICALLY IDENTIFIED AS BEING CHANGED, SUPPLEMENTED, OR AMENDED IN WRITING ISSUED BY THE SANDIA CONTRACTING REPRESENTATIVE.

  18. AmeriFlux CR-Lse La Selva

    SciTech Connect (OSTI)

    Loescher, Hank

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CR-Lse La Selva. Site Description - Site was occupied by Native Americans since 3000 B.P. practicing shifting cultivation. Some selective cutting along rivers (heart of palm). Charcoal dating indicate fires 2400 B.P. and 1100 B.P. Some clearing for pasture/cocoa production, second growth, humid tropical rain forest. Site resides on land presently owned by the Organization for Tropical Studies.

  19. Reactions of hydrogen with V-Cr-Ti alloys

    SciTech Connect (OSTI)

    DiStefano, J.R.; DeVan, J.H.; Chitwood, L.D.; Roehrig, D.H.

    1998-09-01

    In the absence of increases in oxygen concentration, additions of up to 400 ppm hydrogen to V-4 Cr-4 Ti did not result in significant embrittlement as determined by room temperature tensile tests. However, when hydrogen approached 700 ppm after exposure at 325 C, rapid embrittlement occurred. In this latter case, hydride formation is the presumed embrittlement cause. When oxygen was added during or prior to hydrogen exposure, synergistic effects led to significant embrittlement by 100 ppm hydrogen.

  20. Electronic-to-vibrational energy transfer from Br* to CO2 and electronic-to-vibrational laser feasibility studies. Master's thesis

    SciTech Connect (OSTI)

    Katapski, S.M.

    1992-11-01

    The energy transfer mechanism from photo-excited bromine atoms (Br(2P sub 1/2)) to C02 is investigated in a pulsed fluorescence experiment. An excimer-pumped pulsed dye laser operating at 480 nm is used to photolyze molecular bromine, resulting in the creation of one excited state bromine atom, Br(2P sub 1/2), and one ground state atom, Br(2P sub 3/2). The electronically-excited bromine atoms (referred to as Br*) collide with and excite vibrational modes in the ground electronic state of CO2. Measurements are made of the Br* lifetimes and associated quenching processes, and the electronic-to-vibrational (E yields V) energy transfer rate from Br* to CO2. The feasibility of subsequent stimulated emission from the CO2 on the (101)-(100)(4.3 micron) transition is studied, and attempts are made to achieve lasing. Limitations of the experimental apparatus prevented achieving stimulated emission on the 4.3 micron transition. Recommendations are made for improvements in the analysis and apparatus for further research.... Bromine, Spin-orbit relaxation, Quenching, E-V energy transfer.

  1. Preparation, characterization and photocatalytic activity of visible-light-driven plasmonic Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposites

    SciTech Connect (OSTI)

    Li, Xiaojuan Tang, Duanlian; Tang, Fan; Zhu, Yunyan; He, Changfa; Liu, Minghua Lin, Chunxiang; Liu, Yifan

    2014-08-15

    Highlights: A plasmonic Ag/AgBr/ZnFe{sub 2}O{sub 4} photocatalyst has been successfully synthesized. Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposites exhibit high visible light photocatalytic activity. Ag/AgBr/ZnFe{sub 2}O{sub 4} photocatalyst is stable and magnetically separable. - Abstract: A visible-light-driven plasmonic Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposite has been successfully synthesized via a depositionprecipitation and photoreduction through a novel one-pot process. X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and UVvis diffuse reflectance spectroscopy were employed to investigate the crystal structure, chemical composition, morphology, and optical properties of the as-prepared nanocomposites. The photocatalytic activities of the nanocomposites were evaluated by photodegradation of Rhodamine B (RhB) and phenol under visible light. The results demonstrated that the obtained Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposites exhibited higher photocatalytic activity as compared to pure ZnFe{sub 2}O{sub 4}. In addition, the sample photoreduced for 20 min and calcined at 500 C achieved the highest photocatalytic activity. Furthermore, the Ag/AgBr/ZnFe{sub 2}O{sub 4} nanocomposite has high stability under visible light irradiation and could be conveniently separated by using an external magnetic field.

  2. Watermelon-like iron nanoparticles: Cr doping effect on magnetism and magnetization interaction reversal

    SciTech Connect (OSTI)

    Kaur, Maninder; Dai, Qilin; Bowden, Mark E.; Engelhard, Mark H.; Wu, Yaqiao; Tang, Jinke; Qiang, You

    2013-06-26

    Chromium (Cr) forms a solid solution with iron (Fe) lattice when doped in core-shell iron -iron oxide nanocluster (NC) and shows a mixed phase of sigma (?) FeCr and bcc Fe. The Cr dopant affects heavily the magnetization and magnetic reversal process, and causes the hysteresis loop to shrink near the zero field axis. Dramatic transformation happens from dipolar interaction (0 at. % Cr) to strong exchange interaction (8 at. % of Cr) is confirmed from the Henkel plot and delta M plot, and is explained by a water-melon model of core-shell NC system.

  3. Cr{sub 2}Nb-based alloy development

    SciTech Connect (OSTI)

    Liu, C.T.; Tortorelli, P.F.; Horton, J.A.; Easton, D.S.; Heatherly, L.

    1996-06-01

    The objective of this work is to develop a new generation of structural materials based on intermetallic alloys for use at high temperatures in advanced fossil energy conversion systems. Target applications of such ultrahigh strength alloys include hot components (for example, air heat exchangers) in advanced energy conversion systems and heat engines. However, these materials may also find use as wear-resistant parts in coal handling systems (for example, nozzles), drill bits for oil/gas wells, and valve guides in diesel engines. One potential class of such alloys is that based on Cr-Cr{sub 2}Nb alloys. The intermetallic phase, Cr{sub 2}Nb, with a complex cubic structure (C-15) has been selected for initial development because of its high melting point (1770{degrees}C), relatively low material density (7.7 g/cm{sup 2}), and excellent high-temperature strength (at 1000 to 1250{degrees}C). This intermetallic phase, like many other Laves phases, has a wide range of compositional homogeneity suggesting the possibility of improving its mechanical and metallurgical properties by alloying additions.

  4. Low temperature spin dynamics in Cr{sub 7}Ni-Cu-Cr{sub 7}Ni coupled molecular rings

    SciTech Connect (OSTI)

    Bordonali, L.; Furukawa, Y.; Mariani, M.; Sabareesh, K. P. V.; Garlatti, E.; Borsa, F.

    2014-05-07

    Proton Nuclear Magnetic Resonance (NMR) relaxation measurements have been performed down to very low temperature (50 mK) to determine the effect of coupling two Cr{sub 7}Ni molecular rings via a Cu{sup 2+} ion. No difference in the spin dynamics was found from nuclear spin lattice relaxation down to 1.5 K. At lower temperature, the {sup 1}H-NMR line broadens dramatically indicating spin freezing. From the plot of the line width vs. magnetization, it is found that the freezing temperature is higher (260 mK) in the coupled ring with respect to the single Cr{sub 7}Ni ring (140 mK)

  5. Theoretical investigation of structural properties of CuCl, CuBr and CuI compounds under hydrostatic pressure

    SciTech Connect (OSTI)

    Louhibi-Fasla, S.; Djabri, H. Rekab; Achour, H.; Kefif, K.

    2013-12-16

    We have applied a recent version of the full potential linear muffin-tin orbitals method (FPLMTO) to study the structural properties of copper halides CuX (X=Cl, Br, I) under high pressure using the generalized gradient approximation (GGA) for the exchange and correlation potential by Perdew et al. Results are given for lattice parameters, bulk modulus and its first derivatives in the wurtzite(B4), zinc-blende (B3), CsCl (B2), rock-salt (B1), and PbO (B10) structures. The results of these calculations are compared with the available theoretical and experimental data.

  6. Nanostructured Lanthanum Halides and CeBr3 for Nuclear Radiation and Detection

    SciTech Connect (OSTI)

    Paul Guss, Sanjoy Mukhopadhyay, Ron Guise, Ding Yuan

    2010-06-09

    Scintillator materials are used to detect, and in some cases identify, gamma rays. Higher performance scintillators are expensive, hard to manufacture, fragile, and sometimes require liquid nitrogen or cooling engines. But whereas lower-quality scintillators are cheap, easy to manufacture, and more rugged, their performance is lower. At issue: can the desirable qualities of high-and low-performance scintillators be combined to achieve better performance at lower cost? Preliminary experiments show that a LaF{sub 3}:Ce oleic acid-based nanocomposite exhibits a photopeak when exposed to {sup 137}Cs source gamma-radiation. The chemical synthesis of the cerium-doped lanthanum halide nanoparticles are scalable and large quantities of material can be produced at a time, unlike typical crystal growth processes such as the Bridgeman process. Using a polymer composite (Figure 1), produced by LANL, initial measurements of the unloaded and 8% LaF{sub 3}:Ce-loaded sample have been made using {sup 137}Cs sources. Figure 2 shows an energy spectrum acquired for CeF{sub 3}. The lighter plot is the measured polymer-only spectrum and the black plot is the spectrum from the nanocomposite scintillator. As the development of this material continues, the energy resolution is expected to improve and the photopeak-to-Compton ratio will become greater at higher loadings. These measurements show the expected Compton edge in the polymer-only sample, and the Compton edge and photo-peak expected in the nanophosphor composites that LANL has produced. Using a porous VYCORR with CdSe/ZnS core shell quantum dots, Letant has demonstrated that he has obtained signatures of the 241Am photopeak with energy resolution as good at NaI (Figure 3). We begin with the fact that CeBr{sub 3} crystals do not have a self-activity component as strong as the lanthanum halides. The radioactive 0.090% {sup 138}La component of lanthanum leads to significant self-activity, which will be a problem for very large

  7. Optical and electron paramagnetic resonance studies of Cr doped Ga{sub 2}O{sub 3} nanoparticles

    SciTech Connect (OSTI)

    Popa, A. Toloman, D.; Stan, M.; Silipas, T. D.; Biris, A. R.

    2015-12-23

    In the present work we report the experimental results obtained on Ga{sub 2}O{sub 3} nanoparticles doped with Cr ions. X-ray diffraction analysis confirms the substitution of Ga ions with Cr ions. A secondary phase of Cr{sub 2}O{sub 5} oxides was evidence at high doping Cr concentration by Raman spectroscopy. Different valence state of Cr ions was highlighted by UV-VIS spectroscopy. EPR spectroscopy data show the presence of different environments for Cr ions, depending on the Cr addition.

  8. Cr(OH)₃(s) Oxidation Induced by Surface Catalyzed Mn(II) Oxidation

    SciTech Connect (OSTI)

    Namgung, Seonyi; Kwon, M.; Qafoku, Nikolla; Lee, Gie Hyeon

    2014-09-16

    This study examined the feasibility of Cr(OH)₃(s) oxidation mediated by surface catalyzed Mn(II) oxidation under common groundwater pH conditions as a potential pathway of natural Cr(VI) contaminations. Dissolved Mn(II) (50 μM) was reacted with or without synthesized Cr(OH)₃(s) (1.0 g/L) at pH 7 – 9 under oxic or anoxic conditions. In the absence of Cr(OH)₃(s), homogeneous Mn(II) oxidation by dissolved O₂ was not observed at pH ≤ 8.0 for 50 d. At pH 9.0, by contrast, dissolved Mn(II) was completely removed within 8 d and precipitated as hausmannite. When Cr(OH)₃(s) was present, this solid was oxidized and released substantial amounts of Cr(VI) as dissolved Mn(II) was added into the suspension at pH ≥ 8.0 under oxic conditions. Our results suggest that Cr(OH)₃(s) was readily oxidized by a newly formed Mn oxide as a result of Mn(II) oxidation catalyzed on Cr(OH)₃(s) surface. XANES analysis of the residual solids after the reaction between 1.0 g/L Cr(OH)₃(s) and 204 μM Mn(II) at pH 9.0 for 22 d revealed that the product of surface catalyzed Mn(II) oxidation resembled birnessite. The rate and extent of Cr(OH)₃(s) oxidation was likely controlled by those of surface catalyzed Mn(II) oxidation as the production of Cr(VI) increased with increasing pH and initial Mn(II) concentrations. This study evokes the potential environmental hazard of sparingly soluble Cr(OH)₃(s) that can be a source of Cr(VI) in the presence of dissolved Mn(II).

  9. Impact of membrane characteristics on the performance and cycling of the Br-2-H-2 redox flow cell

    SciTech Connect (OSTI)

    Tucker, MC; Cho, KT; Spingler, FB; Weber, AZ; Lin, GY

    2015-06-15

    The Br-2/H-2 redox flow cell shows promise as a high-power, low-cost energy storage device. In this paper, the effect of various aspects of material selection and processing of proton exchange membranes on the operation of the Br-2/H-2 redox flow cell is determined. Membrane properties have a significant impact on the performance and efficiency of the system. In particular, there is a tradeoff between conductivity and crossover, where conductivity limits system efficiency at high current density and crossover limits efficiency at low current density. The impact of thickness, pretreatment procedure, swelling state during cell assembly, equivalent weight, membrane reinforcement, and addition of a microporous separator layer on this tradeoff is assessed. NR212 (50 mu m) pretreated by soaking in 70 degrees C water is found to be optimal for the studied operating conditions. For this case, an energy efficiency of greater than 75% is achieved for current density up to 400 mA cm(-2), with a maximum obtainable energy efficiency of 88%. A cell with this membrane was cycled continuously for 3164 h. Membrane transport properties, including conductivity and bromine and water crossover, were found to decrease moderately upon cycling but remained higher than those for the as-received membrane. (C) 2015 Elsevier B.V. All rights reserved.

  10. Preliminary design report: Babcock and Wilcox BR-100 100-ton rail/barge spent fuel shipping cask

    SciTech Connect (OSTI)

    1990-02-01

    The purpose of this document is to provide information on burnup credit as applied to the preliminary design of the BR-100 shipping cask. There is a brief description of the preliminary basket design and the features used to maintain a critically safe system. Following the basket description is a discussion of various criticality analyses used to evaluate burnup credit. The results from these analyses are then reviewed in the perspective of fuel burnups expected to be shipped to either the final repository or a Monitored Retrievable Storage (MRS) facility. The hurdles to employing burnup credit in the certification of any cask are then outlines and reviewed. the last section gives conclusions reached as to burnup credit for the BR-100 cask, based on our analyses and experience. All information in this study refers to the cask configured to transport PWR fuel. Boiling Water Reactor (BWR) fuel satisfies the criticality requirements so that burnup credit is not needed. All calculations generated in the preparation of this report were based upon the preliminary design which will be optimized during the final design. 8 refs., 19 figs., 16 tabs.

  11. Microsoft Word - chapter FeCrMo_ver2.doc

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

    Reference on Hydrogen Compatibility of Materials Low-Alloy Ferritic Steels: Tempered Fe-Cr-Mo Alloys (code 1211) Prepared by: B.P. Somerday, Sandia National Laboratories Editors C. San Marchi B.P. Somerday Sandia National Laboratories This report may be updated and revised periodically in response to the needs of the technical community; up-to-date versions can be requested from the editors at the address given below or downloaded at http://www.ca.sandia.gov/matlsTechRef/ . The success of this

  12. Improved oxidation sulfidation resistance of Fe-Cr-Ni alloys

    DOE Patents [OSTI]

    Natesan, K.; Baxter, D.J.

    1983-07-26

    High temperature resistance of Fe-Cr-Ni alloy compositions to oxidative and/or sulfidative conditions is provided by the incorporation of about 1 to 8 wt % of Zr or Nb and results in a two-phase composition having an alloy matrix as the first phase and a fine grained intermetallic composition as the second phase. The presence and location of the intermetallic composition between grains of the matrix provides mechanical strength, enhanced surface scale adhesion, and resistance to corrosive attack between grains of the alloy matrix at temperatures of 500 to 1000/sup 0/C.

  13. Oxidation sulfidation resistance of Fe-Cr-Ni alloys

    DOE Patents [OSTI]

    Natesan, Ken; Baxter, David J.

    1984-01-01

    High temperature resistance of Fe-Cr-Ni alloy compositions to oxidative and/or sulfidative conditions is provided by the incorporation of about 1-8 wt. % of Zr or Nb and results in a two-phase composition having an alloy matrix as the first phase and a fine grained intermetallic composition as the second phase. The presence and location of the intermetallic composition between grains of the matrix provides mechanical strength, enhanced surface scale adhesion, and resistance to corrosive attack between grains of the alloy matrix at temperatures of 500.degree.-1000.degree. C.

  14. Characterization of modified 9 Cr-1 Mo steel extruded pipe

    SciTech Connect (OSTI)

    Sikka, V.K.; Hart, M.D.

    1985-04-01

    The fabrication of hot-extruded pipe of modified 9 Cr-1 Mo steel at Cameron Iron Works is described. The report also deals with the tempering response; tensile, Charpy impact, and creep properties; and microstructure of the hot-extruded pipe. The tensile properties of the pipe are compared with the average and average -1.65 standard error of estimate curves for various product forms of several commercial heats of this alloy. The creep-rupture properties are compared with the average curve for various product forms of the commercial heats.

  15. High temperature tensile properties of V-4Cr-4Ti

    SciTech Connect (OSTI)

    Zinkle, S.J.; Rowcliffe, A.F.; Stevens, C.O.

    1998-09-01

    Tensile tests have been performed on V-4Cr-4Ti at 750 and 800 C in order to extend the data base beyond the current limit of 700 C. From comparison with previous measurements, the yield strength is nearly constant and tensile elongations decrease slightly with increasing temperature between 300 and 800 C. The ultimate strength exhibits an apparent maximum near 600 C (attributable to dynamic strain aging) but adequate strength is maintained up to 800 C. The reduction in area measured on tensile specimens remained high ({approximately}80%) for test temperatures up to 800 C, in contrast to previous reported results.

  16. Microsoft Word - CR-AH Policy.doc

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

    After-Hours Policy Original: 11/04 Revised: 2//05 CAMD strives to maintain and improve laboratory and User safety along with User efficiency. After- Hours work inside the cleanroom (CR-AH) is an access privilege that requires deliberate selection of requested Users to maintain a safe, productive environment. * Workdays = 7am - 10pm weekdays * After-Hours = 10pm - 7am workdays + all hours on weekends + all hours of LSU Staff holidays. After-Hours Access Request * Cleanroom-trained Users can apply

  17. Dissociative adsorption of CH{sub 3}X (X = Br and Cl) on a silicon(100) surface revisited by density functional theory

    SciTech Connect (OSTI)

    Wang, Chen-Guang; Huang, Kai E-mail: wji@ruc.edu.cn; Ji, Wei E-mail: wji@ruc.edu.cn

    2014-11-07

    During the dissociative adsorption on a solid surface, the substrate usually participates in a passive manner to accommodate fragments produced upon the cleavage of the internal bond(s) of a (transient) molecular adsorbate. This simple picture, however, neglects the flexibility of surface atoms. Here, we report a Density Functional Theory study to revisit our early studies of the dissociative adsorption of CH{sub 3}X (X = Br and Cl) on Si(100). We have identified a new reaction pathway, which involves a flip of a silicon dimer; this new pathway agrees better with experiments. For our main exemplar of CH{sub 3}Br, insights have been gained using a simple model that involves a three-atom reactive center, Br-C-Si. When the silicon dimer flips, the interaction between C and Si in the Br-C-Si center is enhanced, evident in the increased energy-split of the frontier orbitals. We also examine how the dissociation dynamics of CH{sub 3}Br is altered on a heterodimer (Si-Al, Si-P, and Si-Ge) in a Si(100) surface. In each case, we conclude, on the basis of computed reaction pathways, that no heterodimer flipping is involved before the system transverses the transition state to dissociative adsorption.

  18. Ferromagnetism at room temperature in Cr-doped anodic titanium dioxide nanotubes

    SciTech Connect (OSTI)

    Liao, Yulong E-mail: hwzhang@uestc.edu.cn; Zhang, Huaiwu E-mail: hwzhang@uestc.edu.cn; Li, Jie; Yu, Guoliang; Zhong, Zhiyong; Bai, Feiming; Jia, Lijun; Zhang, Shihong; Zhong, Peng

    2014-05-07

    This study reports the room-temperature ferromagnetism in Cr-doped TiO{sub 2} nanotubes (NTs) synthesized via the electrochemical method followed by a novel Cr-doping process. Scanning electron microscopy and transmission electron microscopy showed that the TiO{sub 2} NTs were highly ordered with length up to 26 ?m, outer diameter about 110 nm, and inner diameter about 100 nm. X-ray diffraction results indicated there were no magnetic contaminations of metallic Cr clusters or any other phases except anatase TiO{sub 2}. The Cr-doped TiO{sub 2} NTs were further annealed in oxygen, air and argon, and room-temperature ferromagnetism was observed in all Cr-doped samples. Moreover, saturation magnetizations and coercivities of the Cr-doped under various annealing atmosphere were further analyzed, and results indicate that oxygen content played a critical role in the room-temperature ferromagnetism.

  19. Effects of Cr doping on the magnetic properties of multiferroic YMnO{sub 3}

    SciTech Connect (OSTI)

    Han, Tai-Chun Wu, I-Chu; Hsu, Hsin-Kai

    2014-05-07

    We have synthesized a series of YMn{sub 1?x}Cr{sub x}O{sub 3} (0???x???0.1) samples and study the effect of Cr-doping on their magnetic properties. The magnetic characterization indicates that with increasing Cr-content up to 0.1, the antiferromagnetic (AFM) transition temperature increases from 73 to 89?K. Our experiment results also indicate that the Cr-doped samples exhibit the characteristics of spin-glass state at low temperature. Moreover, the magnetic hysteresis curves of the doped samples show a weak ferromagnetic (FM) behavior. It is found that the spin-glass state of the Cr-doped samples is due to the competition between AFM superexchange and FM double-exchange interaction, induced by the Cr doping.

  20. The response of CR-39 nuclear track detector to 1-9 MeV protons

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

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Johnson, M. Gatu; Seguin, F. H.; Frenje, J. A.; et al

    2011-10-28

    The response of CR-39 nuclear track detector (TasTrak®) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. The effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather thanmore » the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.« less

  1. Irradiation-enhanced α' precipitation in model FeCrAl alloys

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

    Edmondson, Philip D.; Briggs, Samuel A.; Yamamoto, Yukinori; Howard, Richard H.; Sridharan, Kumar; Terrani, Kurt A.; Field, Kevin G.

    2016-02-17

    Model FeCrAl alloys with varying compositions (Fe(10–18)Cr(10–6)Al at.%) have been neutron irradiated at ~ 320 to damage levels of ~ 7 displacements per atom (dpa) to investigate the compositional influence on the formation of irradiation-induced Cr-rich α' precipitates using atom probe tomography. In all alloys, significant number densities of these precipitates were observed. Cluster compositions were investigated and it was found that the average cluster Cr content ranged between 51.1 and 62.5 at.% dependent on initial compositions. This is significantly lower than the Cr-content of α' in binary FeCr alloys. As a result, significant partitioning of the Al from themore » α' precipitates was also observed.« less

  2. Unusual Mott transition in multiferroic PbCrO 3

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

    Wang, Shanmin; Zhu, Jinlong; Zhang, Yi; Yu, Xiaohui; Zhang, Jianzhong; Wang, Wendan; Bai, Ligang; Qian, Jiang; Yin, Liang; Sullivan, Neil S.; et al

    2015-11-24

    The Mott insulator in correlated electron systems arises from classical Coulomb repulsion between carriers to provide a powerful force for electron localization. When turning such an insulator into a metal, the so-called Mott transition, is commonly achieved by "bandwidth" control or "band filling." However, both mechanisms deviate from the original concept of Mott, which attributes such a transition to the screening of Coulomb potential and associated lattice contraction. We report a pressure-induced isostructural Mott transition in cubic perovskite PbCrO3. At the transition pressure of similar to 3 GPa, PbCrO3 exhibits significant collapse in both lattice volume and Coulomb potential. Concurrentmore » with the collapse, it transforms from a hybrid multiferroic insulator to a metal. For the first time to our knowledge, these findings validate the scenario conceived by Mott. Close to the Mott criticality at similar to 300 K, fluctuations of the lattice and charge give rise to elastic anomalies and Laudau critical behaviors resembling the classic liquid-gas transition. Moreover, the anomalously large lattice volume and Coulomb potential in the low-pressure insulating phase are largely associated with the ferroelectric distortion, which is substantially suppressed at high pressures, leading to the first-order phase transition without symmetry breaking.« less

  3. Electronic and magnetic properties of Cr doped graphene; Full potential approach

    SciTech Connect (OSTI)

    Thakur, Jyoti Kashyap, Manish K.; Saini, Hardev S.

    2015-08-28

    The electronic and magnetic properties of pristine and Cr doped graphene have been calculated using WIEN2k implementation of full potential linearized augmented plane wave (FPLAPW) method based on Density Functional Theory (DFT). The exchange and correlation (XC) effects were taken into account by generalized gradient approximation (GGA). The calculated results show that Cr doping introduces appropriate magnetic moment on graphene. The p-d interaction between 3d states of Cr atom and p-states of C atom are responsible for half metallicity in graphene. The calculated Half-metallic behavior of Cr-doped graphene makes it an ideal candidate for spintronic applications.

  4. Phase Diagram of CuCrO2 in a Magnetic Field

    SciTech Connect (OSTI)

    Fishman, Randy Scott

    2011-01-01

    The magnetic phase diagram of CuCrO2 is constructed as a function of magnetic field and anisotropy using a trial spin state built from harmonics of a fundamental ordering wavevector. Whereas the multiferroic phase of CuCrO2 is a modified spin spiral with a 3-sublattice (SL) period, the phase diagram also contains 1-SL, 2-SL, 4-SL, and 5-SL collinear states which may be accessi- ble in the nonstoichiometric compound CuCrO2+ . For small anisotropy, CuCrO2 is predicted to undergo a transition between two modified spiral states with an intervening 3-SL collinear phase.

  5. Structural studies and band gap tuning of Cr doped ZnO nanoparticles

    SciTech Connect (OSTI)

    Srinet, Gunjan Kumar, Ravindra Sajal, Vivek

    2014-04-24

    Structural and optical properties of Cr doped ZnO nanoparticles prepared by the thermal decomposition method are presented. X-ray diffraction studies confirmed the substitution of Cr on Zn sites without changing the wurtzite structure of ZnO. Modified form of W-H equations was used to calculate various physical parameters and their variation with Cr doping is discussed. Significant red shift was observed in band gap, i.e., a band gap tuning is achieved by Cr doping which could eventually be useful for optoelectronic applications.

  6. Environmental effects on noble-gas hydrides: HXeBr, HXeCCH, and HXeH in noble-gas and molecular matrices

    SciTech Connect (OSTI)

    Tsuge, Masashi E-mail: leonid.khriachtchev@helsinki.fi; Lignell, Antti; Rsnen, Markku; Khriachtchev, Leonid E-mail: leonid.khriachtchev@helsinki.fi

    2013-11-28

    Noble-gas hydrides HNgY (Ng is a noble-gas atom and Y is an electronegative group) are sensitive probes of local environment due to their relatively weak bonding and large dipole moments. We experimentally studied HXeBr in Ar, Kr, and N{sub 2} matrices, HXeCCH in Ne and N{sub 2} matrices, and HXeH in an N{sub 2} matrix. These are the first observations of noble-gas hydrides in an N{sub 2} matrix. An N{sub 2} matrix strongly increases the HXe stretching frequency of HXeBr and HXeCCH with respect to a Ne matrix, which is presumably due to a strong interaction between the HNgY dipole moment and quadrupole moments of the surrounding lattice N{sub 2} molecules. The spectral shift of HXeBr in an N{sub 2} matrix is similar to that in a CO{sub 2} matrix, which is a rather unexpected result because the quadrupole moment of CO{sub 2} is about three times as large as that of N{sub 2}. The HXe stretching frequencies of HXeBr and HXeCCH in noble-gas matrices show a trend of ?(Ne) < ?(Xe) < ?(Kr) < ?(Ar), which is a non-monotonous function of the dielectric constants of the noble-gas solids. The MP2(full) calculations of HXeBr and HXeCCH with the polarizable continuum model as well as the CCSD(T) calculations of the HXeBrNg and HXeCCHNg (Ng = Ne, Ar, Kr, and Xe) complexes cannot fully explain the experimental observations. It is concluded that more sophisticated computational models should be used to describe these experimental findings.

  7. Stabilized wide bandgap MAPbBrxI3-x 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 CH3NH3PbIxBr3–x 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 CH3NH3PbIxBr3–x films could stabilize these materials under one sun illumination, improving both the efficiency and stability of the wide-bandgap perovskite solar cells.

  8. Low Surface Recombination Velocity in Solution-Grown CH3NH3PbBr3 Perovskite Single Crystal

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

    Yang, Ye; Yan, Yong; Yang, Mengjin; Choi, Sukgeun; Zhu, Kai; Luter, Joseph M.; Beard, Matthew C.

    2015-08-06

    Organic-inorganic hybrid perovskites are attracting intense research effort due to their impressive performance in solar cells. While the carrier transport parameters such as mobility and bulk carrier lifetime shows sufficient characteristics, the surface recombination, which can have major impact on the solar cell performance, has not been studied. Here we measure surface recombination dynamics in CH3NH3PbBr3 perovskite single crystals using broadband transient reflectance spectroscopy. The surface recombination velocity is found to be 3.4±0.1 103 cm s-1, B2–3 orders of magnitude lower than that in many important unpassivated semiconductors employed in solar cells. Our result suggests that the planar grain sizemore » for the perovskite thin films should be larger thanB30 mm to avoid the influence of surface recombination on the effective carrier lifetime.« less

  9. Magnetic Interaction Reversal In Watermelon Nanostructured Cr-doped Fe Nanoclusters

    SciTech Connect (OSTI)

    Kaur, Maninder; Dai, Qilin; Bowden, Mark E.; Engelhard, Mark H.; Wu, Yaqiao; Tang, Jinke; Qiang, You

    2013-11-11

    Cr-doped core-shell Fe/Fe-oxide nanoclusters (NCs) were synthesized at varied atomic percentages of Cr from 0 at. % to 8 at. %. The low concentrations of Cr (<10 at. %) were selected in order to inhibit the complete conversion of the Fe-oxide shell to Cr2O3 and the Fe core to FeCr alloy. The magnetic interaction in Fe/Fe-oxide NCs (rv25 nm) can be controlled by antiferromagnetic Cr-dopant. We report the origin of r-FeCr phase at very low Cr concentration (2 at. %) unlike in previous studies, and the interaction reversal from dipolar to exchange interaction in watermelon-like Cr-doped core-shell NCs. The giant magnetoresistance (GMR) effect,1,2 where an antiferromagnetic (AFM) exchange coupling exists between two ferromagnetic (FM) layers separated by a certain type of magnetic or non-magnetic spacer,3 has significant potential for application in the magnetic recording industry. Soon after the discovery of the GMR, the magnetic properties of multilayer systems (FeCr) became a subject of intensive study. The application of bulk iron-chromium (Fe-Cr) alloys has been of great interest, as these alloys exhibit favorable prop- erties including corrosion resistance, high strength, hardness, low oxidation rate, and strength retention at elevated temper- ature. However, the structural and magnetic properties of Cr-doped Fe nanoclusters (NCs) have not been investigated in-depth. Of all NCs, Fe-based clusters have unique magnetic properties as well as favorable catalytic characteristics in reactivity, selectivity, and durability.4 The incorporation of dopant of varied type and concentration in Fe can modify its chemical ordering, thereby optimizing its electrical, optical, and magnetic properties and opening up many new applications. The substitution of an Fe atom (1.24 A˚ ) by a Cr atom (1.25 A˚ ) can easily modify the magnetic properties, since (i) the curie temperature (Tc ) of Fe is 1043 K, while Cr is an itinerant AFM with a bulk Neel temperature TN =311 K, and (ii) Fe

  10. Improving thermostability of CrO{sub 2} thin films by doping with Sn

    SciTech Connect (OSTI)

    Ding, Yi; Wang, Ziyu; Liu, Shuo; Shi, Jing; Yin, Di; Yuan, Cheng; Lu, Zhihong; Xiong, Rui

    2014-09-01

    Chromium dioxide (CrO{sub 2}) is an ideal material for spin electronic devices since it has almost 100% spin polarization near Fermi level. However, it is thermally unstable and easily decomposes to Cr{sub 2}O{sub 3} even at room temperature. In this study, we try to improve the thermal stability of CrO{sub 2} thin films by doping with Sn whose oxide has the same structure as CrO{sub 2}. High quality epitaxial CrO{sub 2} and Sn-doped CrO{sub 2} films were grown on single crystalline TiO{sub 2} (100) substrates by chemical vapor deposition. Sn{sup 4+} ions were believed to be doped into CrO{sub 2} lattice and take the lattice positions of Cr{sup 4+}. The magnetic measurements show that Sn-doping leads to a decrease of magnetocrystalline anisotropy. The thermal stabilities of the films were evaluated by annealing the films at different temperatures. Sn-doped films can withstand a temperature up to 510 °C, significantly higher than what undoped films can do (lower than 435 °C), which suggests that Sn-doping indeed enhances the thermal stability of CrO{sub 2} films. Our study also indicates that Sn-doping may not change the essential half metallic properties of CrO{sub 2}. Therefore, Sn-doped CrO{sub 2} is expected to be very promising for applications in spintronic devices.

  11. Melting of Pb Charge Glass and Simultaneous Pb-Cr Charge Transfer in PbCrO3 as the Origin of Volume Collapse

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

    Yu, Runze; Hojo, Hajime; Watanuki, Tetsu; Mizumaki, Masaichiro; Mizokawa, Takashi; Okada, Kengo; Kim, Hyunjeong; Machida, Akihiko; Sakaki, Kouji; Nakamura, Yumiko; et al

    2015-09-15

    A metal to insulator transition in integer or half integer charge systems can be regarded as crystallization of charges. The insulating state tends to have a glassy nature when randomness or geometrical frustration exists. In this paper, we report that the charge glass state is realized in a perovskite compound PbCrO3, which has been known for almost 50 years, without any obvious inhomogeneity or triangular arrangement in the charge system. PbCrO3 has a valence state of Pb2+0.5Pb4+0.5Cr3+O3 with Pb2+–Pb4+ correlation length of three lattice-spacings at ambient condition. A pressure induced melting of charge glass and simultaneous Pb–Cr charge transfer causesmore » an insulator to metal transition and ~10% volume collapse.« less

  12. Structural, thermal, and photoacoustic study of nanocrystalline Cr{sub 3}Ge produced by mechanical alloying

    SciTech Connect (OSTI)

    Prates, P. B.; Maliska, A. M.; Ferreira, A. S.; Borges, Z. V.; Lima, J. C. de

    2015-10-21

    A thermodynamic analysis of the Cr-Ge system suggested that it was possible to produce a nanostructured Cr{sub 3}Ge phase by mechanical alloying. The same analysis showed that, due to low activation energies, Cr-poor crystalline and/or amorphous alloy could also be formed. In fact, when the experiment was performed, Cr{sub 11}Ge{sub 19} and amorphous phases were present for small milling times. For milling times larger than 15 h these additional phases decomposed and only the nanostructured Cr{sub 3}Ge phase remained up to the highest milling time used (32 h). From the differential scanning calorimetry measurements, the Avrami exponent n was obtained, indicating that the nucleation and growth of the nanostructured Cr{sub 3}Ge phase may be restricted to one or two dimensions, where the Cr and Ge atoms diffuse along the surface and grain boundaries. In addition, contributions from three-dimensional diffusion with a constant nucleation rate may be present. The thermal diffusivity of the nanostructured Cr{sub 3}Ge phase was determined by photoacoustic absorption spectroscopy measurements.

  13. Metastable bcc phase formation in the Nb-Cr-Ti system

    SciTech Connect (OSTI)

    Thoma, D.J.; Perepezko, J.H.

    1994-08-01

    Metastable disordered bcc phases have been formed from the melt in the Nb-Cr-Ti system where primary Laves phases would develop under equilibrium solidification conditions. Three vertical temperature-composition sections in the ternary system incorporating NbCr, were evaluated: the Nb-Cr binary, the TiCr{sub 2}-NbCr{sub 2} isoplethal section, and the NbCr{sub 2}-Ti plethal section. In the rapid solidification of NbCr{sub 2}, metastable bcc phase formation was not observed, but deviations from NbCr{sub 2} stoichiometry or alloying with Ti was found to promote bcc phase formation by decreasing the required liquid undercooling to reach the metastable bcc liquidus and solidus. The metastable phases were characterized through x-ray diffraction (XRD), and systematic deviations from Vegard`s Rule have been defined in the three plethal sections. The metastable bcc phases decompose at temperatures >800{degrees}C to uniformly refined microstructures. As a result, novel microstructural tailoring schemes are possible through the metastable precursor microstructures.

  14. Audit Report: CR-B-95-02 | Department of Energy

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

    5-02 Audit Report: CR-B-95-02 November 10, 1994 Audit of Management Controls Over Selected Energy Research Major System Acquisitions Audit Report: CR-B-95-02 (1.84 MB) More Documents & Publications Audit Report: IG-0389 Audit Report: IG-0403 Audit Report: IG-0476

  15. Audit Report: CR-MA-95-02 | Department of Energy

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

    MA-95-02 Audit Report: CR-MA-95-02 February 10, 1995 Management Advisory Report on Universities Research Association's Documentation and Technical Closeout Activities Audit Report: CR-MA-95-02 (535.76 KB) More Documents & Publications Audit Report: IG-0389 Audit Report: IG-0407 Audit Report: IG-0520

  16. Solid state phase equilibria and intermetallic compounds of the Al-Cr-Ho system

    SciTech Connect (OSTI)

    Pang, Mingjun; SAIC-GM-Wuling Automobile Co., Ltd., Liuzhou, Guangxi 545007 ; Zhan, Yongzhong; Du, Yong

    2013-02-15

    The solid state phase equilibria of the Al-Cr-Ho ternary system at 500 Degree-Sign C were experimentally investigated. The phase relations at 500 Degree-Sign C are governed by 14 three-phase regions, 29 two-phase regions and 15 single-phase regions. The existences of 10 binary compounds and 2 ternary phases have been confirmed. Al{sub 11}Cr{sub 2}, Al{sub 11}Cr{sub 4} and Al{sub 17}Ho{sub 2} were not found at 500 Degree-Sign C. Crystal structures of Al{sub 9}Cr{sub 4} and Al{sub 8}Cr{sub 4}Ho were determined by the Rietveld X-ray powder data refinement. Al{sub 9}Cr{sub 4} was found to exhibit cubic structure with space group I4-bar 3m (no. 217) and lattice parameters a=0.9107(5) nm. Al{sub 8}Cr{sub 4}Ho crystallizes in ThMn{sub 12} structure type with space group I4/mmm (no. 139) and lattice parameters a=0.8909(4) nm, c=0.5120(5) nm. It is concluded that the obtained Al{sub 4}Cr phase in this work should be {mu}-Al{sub 4}Cr by comparing with XRD pattern of the hexagonal {mu}-Al{sub 4}Mn compound. - Graphical abstract: The solid state phase equilibria of the Al-Cr-Ho ternary system at 500 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer Al-Cr-Ho system has been investigated. Black-Right-Pointing-Pointer Al{sub 9}Cr{sub 4} has cubic structure with space group I4-bar 3m. Black-Right-Pointing-Pointer Al{sub 8}Cr{sub 4}Ho crystallizes in ThMn{sub 12} type with space group I4/mmm. Black-Right-Pointing-Pointer Al{sub 4}Cr phase is {mu}-type at 500 Degree-Sign C.

  17. NEUTRON-INDUCED SWELLING OF Fe-Cr BINARY ALLOYS IN FFTF AT ~400 DEGREES C

    SciTech Connect (OSTI)

    Garner, Francis A.; Greenwood, Lawrence R.; Okita, Taira; Sekimura, Naoto; Wolfer, W. G.

    2002-12-31

    The purpose of this effort is to determine the influence of dpa rate, He/dpa ratio and composition on the void swelling of simple binary Fe-Cr alloys. Contrary to the behavior of swelling of model fcc Fe-Cr-Ni alloys irradiated in the same FFTF-MOTA experiment, model bcc Fe-Cr alloys do not exhibit a dependence of swelling on dpa rate at approximately 400 degrees C. This is surprising in that an apparent flux-sensitivity was observed in an earlier comparative irradiation of Fe-Cr binaries conducted in EBR-II and FFTF. The difference in behavior is ascribed to the higher helium generation rates of Fe-Cr alloys in EBR-II compared to that of FFTF, and also the fact that lower dpa rates in FFTF are accompanied by progressively lower helium generation rates.

  18. Computational prediction and characterization of single-layer CrS{sub 2}

    SciTech Connect (OSTI)

    Zhuang, Houlong L.; Blonsky, Michael N.; Hennig, Richard G.; Johannes, Michelle D.

    2014-01-13

    Using first-principles calculations, we predict a previously unreported bulk CrS{sub 2} phase that is stable against competing phases and a low energy dynamically stable single-layer CrS{sub 2} phase. We characterize the electronic, optical, and piezoelectric properties of this single-layer material. Like single-layer MoS{sub 2}, CrS{sub 2} has a direct bandgap and valley polarization. The optical bandgap of CrS{sub 2} is 1.3?eV, close to the ideal bandgap of 1.4?eV for photovoltaic applications. Applying compressive strain increases the bandgap and optical absorbance, transforming it into a promising photocatalyst for solar water splitting. Finally, we show that single-layer CrS{sub 2} possesses superior piezoelectric properties to single-layer MoS{sub 2}.

  19. CROSSED MOLECULAR BEAM STUDIES OF CHEMILUMINESCENT REACTIONS: F{sub 2} + I{sub 2}, Br{sub 2} and ICl

    SciTech Connect (OSTI)

    Kahler, C.C.; Lee, Y.T.

    1980-05-01

    The chemiluminescent bimolecular halogen-halogen reactions, F{sub 2} + I{sub 2}, Br{sub 2} and ICl, have been studied by the crossed molecular beam technique. Undispersed chemiluminescence was measured as a function of collision energy and, for I{sub 2} + F{sub 2}, as a function of the two beam pressures. Although no spectra were obtained to positively identify the emitters as IF*, ClF* and BrF*, arguments are given to support this identification. The observed reaction thresholds of 4.2 and 5.9 kcal/mole for I{sub 2} + F{sub 2} and ICl + F{sub 2} , respectively, are the same as the threshold energies for production of the stable trihalogens I{sub 2}F and ClF. This coincidence of threshold energies, as well as similar high collision energy behavior, implies that the chemiluminescent reaction proceeds via a stable trihalogen intermediate. This mechanism can explain our results and the results of other workers without resorting to a symmetry forbidden four center reaction mechanism. A threshold of 11.3 kcal/mole was found for Br{sub 2} + F{sub 2} , no threshold for Br{sub 2}F has been previously reported. Laser enhancement of the I{sub 2} + F{sub 2} reaction was attempted, but no enhancement was seen.

  20. Cr(VI) Occurrence and Geochemistry in Water From Public-Supply Wells in California

    SciTech Connect (OSTI)

    Izbicki, John A.; Wright, Michael T.; Seymour, Whitney A.; McCleskey, R. Blaine; Fram, Miranda S.; Belitz, Kenneth; Esser, Bradley K.

    2015-08-18

    Hexavalent chromium, Cr(VI), in 918 wells sampled throughout California between 2004 and 2012 by the Groundwater Ambient Monitoring and Assessment Program—Priority Basin Project (GAMA—PBP) ranged from less than the study reporting limit (SRL) of 1 microgram per liter (μg/L) to 32 μg/L. Statewide, Cr(VI) was reported in 31 percent of sampled wells and equaled or exceeded the recently established (2014) California Maximum Contaminant Level (MCL) for Cr(VI) of 10 μg/L in 4 percent of sampled wells. Cr(VI) data collected for regulatory purposes overestimate Cr(VI) occurrence. Ninety percent of chromium was present as Cr(VI), which was detected more frequently and at higher concentrations in alkaline (pH > 8), oxic water, and more frequently in agricultural and urban land uses compared to native land uses. Chemical, isotopic (tritium and carbon-14), and noble-gas data show high Cr(VI) in water from wells in alluvial aquifers in the southern California deserts result from long groundwater-residence times and geochemical reactions such as silicate weathering that increase pH, while oxic conditions persist. High Cr(VI) in water from wells in alluvial aquifers along the west-side of the Central Valley results from high-chromium abundance in source rock eroded to form those aquifers, and areal recharge processes (including irrigation return) that mobilize chromium from the unsaturated zone. Cr(VI) co-occurred with oxyanions having similar chemistry, including vanadium, selenium, and uranium. Cr(VI) was positively correlated with nitrate, consistent with increased concentrations in areas of agricultural land use and mobilization of chromium from the unsaturated zone by irrigation return.

  1. Integrated Ecogenomics Study for Bioremediation of Cr(VI) at Hanford 100H Area

    SciTech Connect (OSTI)

    Chakraborty, Romy; Chakraborty, Romy

    2008-08-12

    Hexavalent chromium is a widespread contaminant found in groundwater. In order to stimulate microbially mediated Cr(VI)-reduction, a poly-lactate compound was injected into Cr(VI)-contaminated aquifers at site 100H at Hanford. Investigation of bacterial community composition using high-density DNA microarray analysis of 16S rRNA gene products revealed a stimulation of Pseudomonas, Desulfovibrio and Geobacter species amongst others. Enrichment of these organisms coincided with continued Cr(VI) depletion. Functional gene-array analysis of DNA from monitoring well indicated high abundance of genes involved in nitrate-reduction, sulfate-reduction, iron-reduction, methanogenesis, chromium tolerance/reduction. Clone-library data revealed Psedomonas was the dominant genus in these samples. Based on above results, we conducted lab investigations to study the dominant anaerobic culturable microbial populations present at this site and their role in Cr(VI)-reduction. Enrichments using defined anaerobic media resulted in isolation of an iron-reducing, a sulfate-reducing and a nitrate-reducing isolate among several others. Preliminary 16S rDNA sequence analysis identified the isolates as Geobacter metallireducens, Pseudomonas stutzeri and Desulfovibrio vulgaris species respectively. The Pseudomonas isolate utilized acetate, lactate, glycerol and pyruvate as alternative carbon sources, and reduced Cr(VI). Anaerobic washed cell suspension of strain HLN reduced almost 95?M Cr(VI) within 4 hr. Further, with 100?M Cr(VI) as sole electron-acceptor, cells grew to 4.05 x 107 /ml over 24 h after an initial lag, demonstrating direct enzymatic Cr(VI) reduction coupled to growth. These results demonstrate that Cr(VI)-immobilization at Hanford 100H site could be mediated by direct microbial metabolism in addition to indirect chemical reduction of Cr(VI) by end-products of microbial activity.

  2. Cr(VI) Occurrence and Geochemistry in Water From Public-Supply Wells in California

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

    Izbicki, John A.; Wright, Michael T.; Seymour, Whitney A.; McCleskey, R. Blaine; Fram, Miranda S.; Belitz, Kenneth; Esser, Bradley K.

    2015-08-18

    Hexavalent chromium, Cr(VI), in 918 wells sampled throughout California between 2004 and 2012 by the Groundwater Ambient Monitoring and Assessment Program—Priority Basin Project (GAMA—PBP) ranged from less than the study reporting limit (SRL) of 1 microgram per liter (μg/L) to 32 μg/L. Statewide, Cr(VI) was reported in 31 percent of sampled wells and equaled or exceeded the recently established (2014) California Maximum Contaminant Level (MCL) for Cr(VI) of 10 μg/L in 4 percent of sampled wells. Cr(VI) data collected for regulatory purposes overestimate Cr(VI) occurrence. Ninety percent of chromium was present as Cr(VI), which was detected more frequently and atmore » higher concentrations in alkaline (pH > 8), oxic water, and more frequently in agricultural and urban land uses compared to native land uses. Chemical, isotopic (tritium and carbon-14), and noble-gas data show high Cr(VI) in water from wells in alluvial aquifers in the southern California deserts result from long groundwater-residence times and geochemical reactions such as silicate weathering that increase pH, while oxic conditions persist. High Cr(VI) in water from wells in alluvial aquifers along the west-side of the Central Valley results from high-chromium abundance in source rock eroded to form those aquifers, and areal recharge processes (including irrigation return) that mobilize chromium from the unsaturated zone. Cr(VI) co-occurred with oxyanions having similar chemistry, including vanadium, selenium, and uranium. Cr(VI) was positively correlated with nitrate, consistent with increased concentrations in areas of agricultural land use and mobilization of chromium from the unsaturated zone by irrigation return.« less

  3. Development of ODS FeCrAl alloys for accident-tolerant fuel cladding

    SciTech Connect (OSTI)

    Dryepondt, Sebastien N.; Hoelzer, David T.; Pint, Bruce A.; Unocic, Kinga A.

    2015-09-18

    FeCrAl alloys are prime candidates for accident-tolerant fuel cladding due to their excellent oxidation resistance up to 1400 C and good mechanical properties at intermediate temperature. Former commercial oxide dispersion strengthened (ODS) FeCrAl alloys such as PM2000 exhibit significantly better tensile strength than wrought FeCrAl alloys, which would alloy for the fabrication of a very thin (~250 m) ODS FeCrAl cladding and limit the neutronic penalty from the replacement of Zr-based alloys by Fe-based alloys. Several Fe-12-Cr-5Al ODS alloys where therefore fabricated by ball milling FeCrAl powders with Y2O3 and additional oxides such as TiO2 or ZrO2. The new Fe-12Cr-5Al ODS alloys showed excellent tensile strength up to 800 C but limited ductility. Good oxidation resistance in steam at 1200 and 1400 C was observed except for one ODS FeCrAl alloy containing Ti. Rolling trials were conducted at 300, 600 C and 800 C to simulate the fabrication of thin tube cladding and a plate thickness of ~0.6mm was reached before the formation of multiple edge cracks. Hardness measurements at different stages of the rolling process, before and after annealing for 1h at 1000 C, showed that a thinner plate thickness could likely be achieved by using a multi-step approach combining warm rolling and high temperature annealing. Finally, new Fe-10-12Cr-5.5-6Al-Z gas atomized powders have been purchased to fabricate the second generation of low-Cr ODS FeCrAl alloys. The main goals are to assess the effect of O, C, N and Zr contents on the ODS FeCrAl microstructure and mechanical properties, and to optimize the fabrication process to improve the ductility of the 2nd gen ODS FeCrAl while maintaining good mechanical strength and oxidation resistance.

  4. Progress in the material development of LiCaAlF sub 6 :Cr sup 3+ laser crystals

    SciTech Connect (OSTI)

    Michelle D. Shinn.; Chase, L.L.; Caird, J.A.; Payne, S.A.; Atherton, L.J.; Kway, W.L.

    1990-03-01

    High Cr{sup 3+} doping levels, up to 8 mole percent, and low losses have been obtained with the tunable solid-state laser material LiCaAlF{sub 6}:Cr{sup 3+} (Cr:LiCAF). Measurements and calculations show that high pumping and extraction efficiencies are possible with the improved material. 13 refs., 4 figs., 1 tab.

  5. Magnetic properties and hyperfine interactions in Cr{sub 8}, Cr{sub 7}Cd, and Cr{sub 7}Ni molecular rings from {sup 19}F-NMR

    SciTech Connect (OSTI)

    Bordonali, L.; Borsa, F.; Consorzio INSTM, Via Giusti 9, I-50121 Firenze; Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, Iowa 50011 ; Garlatti, E.; Dipartimento di Fisica e Scienze della Terra, Università di Parma, Viale G. P. Usberti 7 Casadei, C. M.; Department of Physics and Astronomy, Ames Laboratory, Iowa State University, Ames, Iowa 50011 ; Furukawa, Y.; Lascialfari, A.; Consorzio INSTM, Via Giusti 9, I-50121 Firenze; Department of Physics, Università degli Studi di Milano, Via Celoria 16, 20133 Milano ; Carretta, S.; Timco, G.; Winpenny, R. E. P.

    2014-04-14

    A detailed experimental investigation of the {sup 19}F nuclear magnetic resonance is made on single crystals of the homometallic Cr{sub 8} antiferromagnetic molecular ring and heterometallic Cr{sub 7}Cd and Cr{sub 7}Ni rings in the low temperature ground state. Since the F{sup −} ion is located midway between neighboring magnetic metal ions in the ring, the {sup 19}F-NMR spectra yield information about the local electronic spin density and {sup 19}F hyperfine interactions. In Cr{sub 8}, where the ground state is a singlet with total spin S{sub T} = 0, the {sup 19}F-NMR spectra at 1.7 K and low external magnetic field display a single narrow line, while when the magnetic field is increased towards the first level crossing field, satellite lines appear in the {sup 19}F-NMR spectrum, indicating a progressive increase in the Boltzmann population of the first excited state S{sub T} = 1. In the heterometallic rings, Cr{sub 7}Cd and Cr{sub 7}Ni, whose ground state is magnetic with S{sub T} = 3/2 and S{sub T} = 1/2, respectively, the {sup 19}F-NMR spectrum has a complicated structure which depends on the strength and orientation of the magnetic field, due to both isotropic and anisotropic transferred hyperfine interactions and classical dipolar interactions. From the {sup 19}F-NMR spectra in single crystals we estimated the transferred hyperfine constants for both the F{sup −}-Ni{sup 2+} and the F{sup −}-Cd{sup 2+} bonds. The values of the hyperfine constants compare well to the ones known for F{sup −}-Ni{sup 2+} in KNiF{sub 3} and NiF{sub 2} and for F{sup −}-Cr{sup 3+} in K{sub 2}NaCrF{sub 6}. The results are discussed in terms of hybridization of the 2s, 2p orbitals of the F{sup −} ion and the d orbitals of the magnetic ion. Finally, we discuss the implications of our results for the electron-spin decoherence.

  6. Temperature-dependent study of ion-channeling in Fe/Cr superlattices

    SciTech Connect (OSTI)

    Rueders, F.; Rehn, L.E.; Baldo, P.M.; Fullerton, E.E.; Bader, S.D.

    1996-05-01

    Giant-Magneto-Resistance (GMR), as large as 150% at 4K, occurs in Fe/Cr superlattices as a result of antiferromagnetic interlayer coupling. The authors have successfully grown epitaxial single-crystal Fe/Cr multilayers using magnetron sputtering. Ion channeling was employed to study the structural and vibrational properties of the sputter-deposited Fe/Cr superlattices, and of a Cr thin film, between temperatures of 100 and 330K. Channeling in the latter specimen was used to investigate the importance of depositing a Cr buffer-layer in order to obtain superlattices with large GMR values. Once the buffer layer exceeded a critical thickness, a high quality Cr film was observed. The epitaxial quality of the superlattices grown on such buffer layers by sputtering was found to be excellent. Minimum yields nearly equal to theoretical predictions were found for channeling along the <001> growth direction; slightly higher values were found along the <111> axis. Because of the high structural quality of the sputter-deposited films, it was possible to investigate changes in thermal vibration amplitudes, even though their magnitude is only of the order of a few pm (10{sup {minus}12} m). No unusual structural changes of this magnitude were observed in angular channeling scans obtained while cooling the Fe/Cr superlattice form 330 down to 100 K.

  7. Ferromagnetic superexchange in insulating Cr2MoO6 by controlling orbital hybridization

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

    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.; et al

    2015-09-11

    We report the magnetic and electronic structures of the newly synthesized inverse-trirutile compound Cr2MoO6. Despite the same crystal symmetry and similar bond-lengths and bond-angles to Cr2TeO6, Cr2MoO6 possesses a magnetic structure of the Cr2MoO6 type, different from that seen in Cr2TeO6. 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 throughmore » orbital hybridization. This approach is fundamentally different from the conventional methods of controlling the exchange interaction by either carrier injection or through structural distortions.« less

  8. Probe Mssbauer spectroscopy of mechanical alloying in binary Cr?{sup 57}Fe(1 at%) system

    SciTech Connect (OSTI)

    Elsukov, Evgeny P. Kolodkin, Denis A. Ul'yanov, Alexander L. Porsev, Vitaly E.

    2014-10-27

    Solid state reactions during mechanical alloying (MA) in a binary mixture of powdered Cr and {sup 57}Fe in atomic ratio of 99:1 have been studied using {sup 57}Fe Mssbauer spectroscopy, X-ray diffraction and Auger spectrometry. The proposed model of MA includes formation of Cr(Fe){sub x}O{sub y} oxides at the contact places of Cr and Fe particles, formation of nanostructure with simultaneous dissolution of the oxides, penetration of Fe atoms along grain boundaries in close-to-boundary distorted zones of interfaces in a substitutional position, formation of the substitutional solid solution of Fe in Cr in the body of grains. It was shown that the increase in the BCC lattice parameter on increasing the milling time is due to the dissolution of oxides and formation of interstitial solid solution of O in Cr. There were established substantial differences in consumption of BCC Fe in a Mg ? Al ? Si ? Cr sequence due to the major role of chemical interaction of Mg(Al,Si,Cr) with Fe.

  9. Effects of competing magnetic interactions on the electronic transport properties of CuCrSe{sub 2}

    SciTech Connect (OSTI)

    Tewari, Girish C.; Jawaharlal Nehru University, New Delhi 110067 ; Karppinen, Maarit; Rastogi, Ashok K.

    2013-02-15

    We have synthesized single-phase samples of the CuCrSe{sub 2} phase that exhibits hexagonal-rhombohedral layered crystal structure with space group R3m. Here we present a detailed study of electronic transport and magnetic properties of CuCrSe{sub 2}. We moreover investigate the heat capacity of CuCrSe{sub 2} in comparison to that of CuCrS{sub 2}. The electrical resistivity of CuCrSe{sub 2} shows metallic-like behavior down to 2 K, while the thermoelectric power is large around 100 {mu}V K{sup -1} at 300 K. A weak anomaly in resistivity and a rounded maximum in magnetic susceptibility are observed around 55 K. No sharp transition at 55 K is observed in the heat capacity of CuCrSe{sub 2}, rather a visible maximum is seen. At low temperatures from 2 to 14 K, the magnetic heat capacity follows T{sup 2}-dependence. We tentatively believe this behavior of CuCrSe{sub 2} to be due to competing magnetic interactions between intralayer Cr atoms. The ferromagnetic Cr-Se-Cr indirect exchange among intralayer Cr atoms is enhanced in the selenide compound (that is more metallic than the sulfide compound), and competes with the antiferromagnetic Cr-Cr direct interactions. The interlayer antiferromagnetic exchange through Cu atoms leads to magnetic ordering at low temperature at T{sub N}=55 K. - Graphical abstract: Comparison of magnetic properties of CuCrSe{sub 2} and CuCrS{sub 2} indicates a sharp cusp-like anomaly in magnetic susceptibility at the antiferromagnetic transition of CuCrS{sub 2} while the maximum of CuCrSe{sub 2} is well rounded. Magnetization is reversible after field-cooling (FC) and zero-field-cooling (ZFC) for both compounds. Highlights: Black-Right-Pointing-Pointer Layered CuCrSe{sub 2} can be synthesized in both fully and partially cation-ordered forms. Black-Right-Pointing-Pointer Contrary to previously believed insulating nature the cation-ordered phase is metallic. Black-Right-Pointing-Pointer Magnetic property of CuCrSe{sub 2} is somewhat different from

  10. Nanoscale Phase Separation In Epitaxial Cr-Mo and Cr-V Alloy Thin Films Studied Using Atom Probe Tomography: Comparison Of Experiments And Simulation

    SciTech Connect (OSTI)

    Devaraj, Arun; Kaspar, Tiffany C.; Ramanan, Sathvik; Walvekar, Sarita K.; Bowden, Mark E.; Shutthanandan, V.; Kurtz, Richard J.

    2014-11-21

    Tailored metal alloy thin film-oxide interfaces generated using molecular beam epitaxial (MBE) deposition of alloy thin films on a single crystalline oxide substrate can be used for detailed studies of irradiation damage response on the interface structure. However presence of nanoscale phase separation in the MBE grown alloy thin films can impact the metal-oxide interface structure. Due to nanoscale domain size of such phase separation it is very challenging to characterize by conventional techniques. Therefor laser assisted atom probe tomography (APT) was utilized to study the phase separation in epitaxial Cr0.61Mo0.39, Cr0.77Mo0.23, and Cr0.32V0.68 alloy thin films grown by MBE on MgO(001) single crystal substrates. Statistical analysis, namely frequency distribution analysis and Pearson coefficient analysis of experimental data was compared with similar analyses conducted on simulated APT datasets with known extent of phase separation. Thus the presence of phase separation in Cr-Mo films, even when phase separation was not clearly observed by x-ray diffraction, and the absence of phase separation in the Cr-V film were thus confirmed.

  11. Nanoscale phase separation in epitaxial Cr-Mo and Cr-V alloy thin films studied using atom probe tomography: Comparison of experiments and simulation

    SciTech Connect (OSTI)

    Devaraj, A.; Ramanan, S.; Walvekar, S.; Bowden, M. E.; Shutthanandan, V.; Kaspar, T. C.; Kurtz, R. J.

    2014-11-21

    Tailored metal alloy thin film-oxide interfaces generated using molecular beam epitaxy (MBE) deposition of alloy thin films on a single crystalline oxide substrate can be used for detailed studies of irradiation damage response on the interface structure. However, the presence of nanoscale phase separation in the MBE grown alloy thin films can impact the metal-oxide interface structure. Due to nanoscale domain size of such phase separation, it is very challenging to characterize by conventional techniques. Therefore, laser assisted atom probe tomography (APT) was utilized to study the phase separation in epitaxial Cr{sub 0.61}Mo{sub 0.39}, Cr{sub 0.77}Mo{sub 0.23}, and Cr{sub 0.32}V{sub 0.68} alloy thin films grown by MBE on MgO(001) single crystal substrates. Statistical analysis, namely frequency distribution analysis and Pearson coefficient analysis of experimental data was compared with similar analyses conducted on simulated APT datasets with known extent of phase separation. Thus, the presence of phase separation in Cr-Mo films, even when phase separation was not clearly observed by x-ray diffraction, and the absence of phase separation in the Cr-V film were confirmed.

  12. Thermodynamic Modeling and Experimental Study of the Fe-Cr-Zr System

    SciTech Connect (OSTI)

    Yang, Ying; Tan, Lizhen; Bei, Hongbin; Busby, Jeremy T

    2013-01-01

    Wide applications of zircaloys, stainless steels and their interactions in nuclear reactors require the knowledge on phase stability and thermodynamic property of the Fe-Cr-Zr system. This knowledge is also important to develop new Zr-contained Fe-Cr ferritic steels. This work aims at developing thermodynamic models for describing phase stability and thermodynamic property of the Fe-Cr-Zr system using the Calphad approach coupled with experimental study. Thermodynamic descriptions of the Fe-Cr and Cr-Zr systems were either directly adopted or slightly modified from literature. The Fe-Zr system has been remodeled to accommodate recent ab-initio calculation of formation enthalpies of various Fe-Zr compounds. Reliable ternary experimental data and thermodynamic models were mainly available in the Zr-rich region. Therefore, selected ternary alloys located in the vicinity of the eutectic valley of (Fe,Cr,Zr) and (Fe,Cr)2Zr laves phase in the Fe-rich region have been experimentally investigated in this study. Microstructure has been examined by using scanning electron microscope, energy-dispersive Xray spectroscopy and X-ray diffraction. These experimental results, along with the literature data were then used to develop thermodynamic models for phases in the Fe-Cr-Zr system. Calculated phase equilibria and thermodynamic properties of the ternary system yield satisfactory agreements with available experimental data, which gives the confidence to use these models as building blocks for developing a Zr, Fe and Cr contained multicomponent thermodynamic database for broader applications in nuclear reactors.

  13. Influence of cassette type on the DQE of CR systems

    SciTech Connect (OSTI)

    Monnin, P.; Holzer, Z.; Wolf, R.; Neitzel, U.; Vock, P.; Gudinchet, F.; Verdun, F. R.

    2006-10-15

    In our recent paper by Monnin et al. [Med. Phys.33, 411-420 (2006)], an objective analysis of the relative performance of a computed radiography (CR) system using both standard single-side (ST-VI) and prototype dual-side read (ST-BD) plates was reported. The presampled modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) for the systems were determined at three different beam qualities representative of paediatric chest radiography, at an entrance detector air kerma of 5 {mu}Gy. Experiments demonstrated that, compared to the standard single-side read system, the MTF for the dual-side read system was slightly reduced, but a significant decrease in image noise resulted in a marked increase in DQE (+40%) in the low spatial frequency range. However, the DQE improvement for the ST-BD plate decreased with increasing spatial frequency, and, at spatial frequencies above 2.2 mm{sup -1}, the DQE of the dual-side read system was lower than that of the single-side one.

  14. Electrochemical Testing of Ni-Cr-Mo-Gd Alloys

    SciTech Connect (OSTI)

    T. E. Lister; R. E. Mizia; H. Tian

    2005-10-01

    The waste package site recommendation design specified a boron-containing stainless steel, Neutronit 976/978, for fabrication of the internal baskets that will be used as a corrosion-resistant neutron-absorbing material. Recent corrosion test results gave higher-than-expected corrosion rates for this material. The material callout for these components has been changed to a Ni-Cr-Mo-Gd alloy (ASTM-B 932-04, UNS N06464) that is being developed at the Idaho National Laboratory. This report discusses the results of initial corrosion testing of this material in simulated in-package environments that could contact the fuel baskets after breach of the waste package outer barrier. The corrosion test matrix was executed using the potentiodynamic and potentiostatic electrochemical test techniques. The alloy performance shows low rates of general corrosion after initial removal of a gadolinium-rich second phase that intersects the surface. The high halide-containing test solutions exhibited greater tendencies toward initiation of crevice corrosion.

  15. Steamside Oxidation Behavior of Experimental 9%Cr Steels

    SciTech Connect (OSTI)

    Dogan, O.N.; Holcomb, G.R.; Alman, D.E.; Jablonski, P.D.

    2007-10-01

    Reducing emissions and increasing economic competitiveness require more efficient steam power plants that utilize fossil fuels. One of the major challenges in designing these plants is the availability of materials that can stand the supercritical and ultra-supercritical steam conditions at a competitive cost. There are several programs around the world developing new ferritic and austenitic steels for superheater and reheater tubes exposed to the advanced steam conditions. The new steels must possess properties better than current steels in terms of creep strength, steamside oxidation resistance, fireside corrosion resistance, and thermal fatigue resistance. This paper introduces a series of experimental 9%Cr steels containing Cu, Co, and Ti. Stability of the phases in the new steels is discussed and compared to the phases in the commercially available materials. The steels were tested under both the dry and moist conditions at 650C for their cyclical oxidation resistance. Results of oxidation tests are presented. Under the moist conditions, the experimental steels exhibited significantly less mass gain compared to the commercial P91 steel. Microstructural characterization of the scale revealed different oxide compositions.

  16. Oxygen-induced immediate onset of the antiferromagnetic stacking in thin Cr films on Fe(001)

    SciTech Connect (OSTI)

    Berti, Giulia Brambilla, Alberto; Calloni, Alberto; Bussetti, Gianlorenzo; Finazzi, Marco; Duò, Lamberto; Ciccacci, Franco

    2015-04-20

    We investigated the magnetic coupling of ultra-thin Cr films grown at 600 K on a Fe(001)-p(1 × 1)O substrate by means of spin-polarized photoemission spectroscopy. Our findings show that the expected antiferromagnetic stacking of the magnetization in Cr(001) layers occurs right from the first atomic layer at the Cr/Fe interface. This is at variance with all previous observations in similar systems, prepared in oxygen-free conditions, which always reported on a delayed onset of the magnetic oscillations due to the occurrence of significant chemical alloying at the interface, which is substantially absent in our preparation.

  17. Hydrothermal synthesis and magnetic properties of ErCrO{sub 4} nanoparticles

    SciTech Connect (OSTI)

    Sundarayya, Y. Kumar, K. Ashwini Sondge, Rajesh Srinath, S. Kaul, S. N.

    2014-04-24

    Homogeneous single phase ErCrO{sub 4} nanoparticles have been synthesized by a modified sol-gel followed by hydrothermal method. X-ray diffraction reveals that the compound crystallizes into tetragonal structure with space group I41/amd. The average crystallite size was estimated to be 21(1) nm. Morphological analysis of the sample confirms uniform particles of size 20 nm. DC magnetic measurements show that ErCrO{sub 4} undergoes a paramagnetic-antiferromagnetic transition at 16 K, due to the superexchange Er-O-Cr-O-Er antiferromagnetic interactions.

  18. Epitaxial Cr on n-SrTiO3(001)An ideal Ohmic contact

    SciTech Connect (OSTI)

    Capan, Cigdem; Sun, Guangyuan; Bowden, Mark E.; Chambers, Scott A.

    2012-01-30

    Epitaxial Cr metallizations grown on n-SrTiO3(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO2 layer, no reduction of the SrTiO3, and a near-perfect Ohmic contact. Cr/n-SrTiO3(001) thus constitutes an ideal interface between a pure metal and wide gap oxide in which interface redox chemistry does not occur, and the Fermi level remains unpinned.

  19. Epitaxial Cr on n-SrTiO{sub 3}(001) - An ideal Ohmic contact

    SciTech Connect (OSTI)

    Capan, C.; Sun, G. Y.; Bowden, M. E.; Chambers, S. A.

    2012-01-30

    Epitaxial Cr metallizations grown on n-SrTiO{sub 3}(001) by molecular beam epitaxy are shown to result in an ordered interface with Cr bound to O in the terminal TiO{sub 2} layer, no reduction of the SrTiO{sub 3}, and a near-perfect Ohmic contact. Cr/n-SrTiO{sub 3}(001) thus constitutes an ideal interface between a pure metal and wide gap oxide in which interface redox chemistry does not occur, and the Fermi level remains unpinned.

  20. CASL - Mixing and non-stoichiometry in Fe-Ni-Cr-Zn-O spinel compounds:

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

    Density functional theory calculations Mixing and non-stoichiometry in Fe-Ni-Cr-Zn-O spinel compounds: Density functional theory calculations Mixing and non-stoichiometry in Fe-Ni-Cr-Zn-O spinel compounds: Density functional theory calculations D.A. Andersson and C.R. Stanek Materials Science and Technology Division Los Alamos National Laboratory Density functional theory (DFT) calculations have been employed to better understand the thermodynamic properties of AB2O4 (where A=Fe2+, Ni2+ or

  1. Remediation of Cr(VI) by biogenic magnetic nanoparticles: An x-ray magnetic circular dichroism study

    SciTech Connect (OSTI)

    Telling, N. D.; Coker, V. S.; Cutting, R. S.; van der Laan, G.; Pearce, C. I.; Pattrick, R. A. D.; Arenholz, E.; Lloyd, J. R.

    2009-09-04

    Biologically synthesized magnetite (Fe{sub 3}O{sub 4}) nanoparticles are studied using x-ray absorption and x-ray magnetic circular dichroism following exposure to hexavalent Cr solution. By examining their magnetic state, Cr cations are shown to exist in trivalent form on octahedral sites within the magnetite spinel surface. The possibility of reducing toxic Cr(VI) into a stable, non-toxic form, such as a Cr{sup 3+}-spinel layer, makes biogenic magnetite nanoparticles an attractive candidate for Cr remediation.

  2. Half-metallic ferromagnetism in Cr-doped semiconducting Ge-chalcogenide: Density functional approach

    SciTech Connect (OSTI)

    Saini, Hardev S.; Singh, Mukhtiyar; Thakur, Jyoti; Kashyap, Manish K.

    2014-04-24

    A supercell approach has been used to calculate the electronic and magnetic properties of Cr-doped Ge chalcogenide, Ge{sub 1−x}Cr{sub x}Te (x = 0.25 and 0.125). The calculations have been performed using full potential Linear Augmented Plane Wave (FPLAPW) method within generalized gradient approximation (GGA) as exchange-correlation (XC) potential. The calculated results show that the doping of Cr induces the 100% spin polarization at Fermi level (EF) and showed the robust half metallic ferromagnetism in this compound. Thus, the compound at both dopant concentrations behave as dilute magnetic semiconductor (DMS) showing metallic property in majority and semiconducting for minority spin channels which is best suited for spintronic applications. The total magnetic moments of this compound are mainly due to Cr-d states present at E{sup F} with negligible contribution from electronic states of other atoms.

  3. Process for producing Ti-Cr-Al-O thin film resistors

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2001-01-01

    Thin films of Ti-Cr-Al-O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti-Cr-Al-O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti-Cr-Al-O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti-Cr-Al-O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  4. Flat panel display using Ti-Cr-Al-O thin film

    DOE Patents [OSTI]

    Jankowski, Alan F.; Schmid, Anthony P.

    2002-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.

  5. Cr(VI) reduction in aqueous solutions by using copper smelter slag

    SciTech Connect (OSTI)

    Kiyak, B.; Oezer, A.; Altundogan, H.S.; Erdem, M.; Tuemen, F. )

    1999-01-01

    The ability of Copper Smelter Slag (CSS) to reduce Cr(VI) in aqueous solutions has been investigated. The extent of reduction if dependent on the amounts of acid and reductant, contact time, Cr(VI) concentration, temperature of the solution and particle size of CSS. The amount of acid is the most important variable affecting the reduction process. When twice the amount of acid required with respect to Cr(VI) was used, Cr(VI) in 100 ml solution (100 mg/l) was completely reduced in a contact period less than 5 min by a 10 g/l dosage of CSS. Reduction efficiency increased with increase in temperature of solution, showing that the process is endothermic. Reduced chromium, and iron and other metals dissolved from CSS were effectively precipitated by using NaOH or calcinated carbonation sludge from sugar plant.

  6. Cr(VI) reduction in aqueous solutions by using copper smelter slag

    SciTech Connect (OSTI)

    Kiyak, B.; Oezer, A.; Altundogan, H.S.; Erdem, M.; Tuemen, F.

    1999-11-01

    The ability of Copper Smelter Slag (CSS) to reduce Cr(VI) in aqueous solutions has been investigated. The extent of reduction if dependent on the amounts of acid and reductant, contact time, Cr(VI) concentration, temperature of the solution and particle size of CSS. The amount of acid is the most important variable affecting the reduction process. When twice the amount of acid required with respect to Cr(VI) was used, Cr(VI) in 100 ml solution (100 mg/l) was completely reduced in a contact period less than 5 min by a 10 g/l dosage of CSS. Reduction efficiency increased with increase in temperature of solution, showing that the process is endothermic. Reduced chromium, and iron and other metals dissolved from CSS were effectively precipitated by using NaOH or calcinated carbonation sludge from sugar plant.

  7. Development of a Full-core Reactivity Equivalence for FeCrAl...

    Office of Scientific and Technical Information (OSTI)

    Reactivity Equivalence for FeCrAl Enhanced Accident Tolerant Fuel in BWRs Citation Details In-Document Search Title: Development of a Full-core Reactivity Equivalence for ...

  8. In Situ Long-Term Reductive Bioimmobilization of Cr(VI) in Groundwater...

    Office of Scientific and Technical Information (OSTI)

    injection into Cr(VI)-contaminated groundwater stimulates an average increase in biomass by up to 50 times, from-5105 to 2.5107 cellsmL. The results also show a...

  9. A pseudo binary y-Gd solidification diagram for Ni-Cr-Mo-Gd alloys...

    Office of Scientific and Technical Information (OSTI)

    Title: A pseudo binary y-Gd solidification diagram for Ni-Cr-Mo-Gd alloys. No abstract prepared. Authors: Dupont, John Neuman 1 ; Minicozzi, Michael J. 1 ; Robino, Charles ...

  10. The Preparation of an Ultrastable Mesoporous Cr(III)-MOF via...

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

    Abstract: Kinetic labilization of the Fe(III)-O coordination bond in a mesoporous metal-organic framework, PCN-333-Fe(III), is realized by the reduction of Fe(III) by Cr(II). The ...

  11. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

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

    Burcklen, C.; Soufli, R.; Gullikson, E.; Meltchakov, E.; Dennetiere, D.; Polack, F.; Capitanio, B.; Thomasset, M.; Jerome, A.; de Rossi, S.; et al

    2016-03-24

    Here, we present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1–1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (opticalmore » constants) values for Cr.« less

  12. Qualification of welded super 13%Cr martensitic stainless steels for the Sgard field

    SciTech Connect (OSTI)

    Enerhaug, J.; Kvaale, P.E.; Bjordal, M.; Drugli, J.M.; Rogne, T.

    1999-11-01

    A test program was conducted to qualify welded super 13%Cr (S13%Cr) stainless steel for the Asgard Field, a mildly sour service. The test program involved girth welding, optimization of post weld heat treatment (PWHT) cycles, assessment of mechanical properties, examination of low cycle fatigue testing, and different corrosion testing and evaluation of S13%Cr steels from three different steel mills. The alloy with 0.015%C max, 11.9%Cr min, 2.4%Mo min and 6.O%Ni min, has been qualified for use as flowline material in the actual field. The results show acceptable weldability and corrosion properties. Post weld heat treatment (PWHT) of the welds improved the resistance against sulfide stress corrosion cracking.

  13. Audit Report: CR-B-99-01 | Department of Energy

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

    Audit Report: CR-B-99-01 October 1, 1998 Department's Working Capital Fund The Department established the Working Capital Fund (Fund) in January 1996 as a financial management tool ...

  14. Audit Report: CR-B-97-04 | Department of Energy

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

    1, 1997 Audit of Controls Over the ADP Support Services Contract PDF icon Audit Report: CR-B-97-04 More Documents & Publications Audit of Selected Hazardous Waste Remedial Actions ...

  15. Audit Report: CR-B-02-01 | Department of Energy

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

    1 Audit Report: CR-B-02-01 October 15, 2001 Fixed-Price Contracting for Department of ... The objective of our audit was to determine if the cost savings anticipated from the use ...

  16. Ultrathin nanosheets of CrSiTe3. A semiconducting two-dimensional...

    Office of Scientific and Technical Information (OSTI)

    As a result, the ferromagnetic mono- and few-layer 2D CrSiTe3 indicated here should enable ... Type: Accepted Manuscript Journal Name: Journal of Materials Chemistry. C Additional ...

  17. Optical Absorption and Band Gap Reduction in (Fe 1-x Cr x ) 2...

    Office of Scientific and Technical Information (OSTI)

    Broadening of the valence band due to hybridization of the O 2p states with Fe and Cr 3d states also contributes to band gap reduction. Authors: Wang, Yong ; Lopata, Kenneth ; ...

  18. Exceptionally high glass-forming ability of an FeCoCrMoCBY alloy...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Exceptionally ... Here we report the exceptionally high GFA of an FeCoCrMoCBY ... OSTI Identifier: 20702296 Resource Type: Journal Article ...

  19. Audit Report: CR-B-95-05 | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    of the Federal Enegy Regulatory Commission's Office of Chief Accountant Audit Report: CR-B-95-05 More Documents & Publications Audit Report: IG-0811 Audit Manual Audit Report:...

  20. Irradiation creep of the US Heat 832665 of V-4Cr-4Ti (Journal...

    Office of Scientific and Technical Information (OSTI)

    The paper presents irradiation creep data for V-4Cr-4Ti irradiated to 3.7 dpa at 425 and 600 C in the HFIR-17J experiment. Creep deformation was characterized by measuring ...

  1. Microsoft Word - chapter FeNiCrMo_ver4.doc

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

    The carbon and alloy steel categories selected for the Technical Reference for Hydrogen ... Since a full range of data is not available for each steel, data for all Ni-Cr-Mo steels ...

  2. Microstructural Stability of 9-12 Cr Steels at Elevated Temperatures

    SciTech Connect (OSTI)

    Dogan, Omer N.; Hawk, Jeffrey A.

    2005-09-01

    The objective of this report is to explore new substitutional solute solution (Cu, Co) and precipitate (TiC) hardening mechanisms for improved strength of 9-12 Cr martensitic steels.

  3. C/CrC nanocomposite coating deposited by magnetron sputtering at high ion irradiation conditions

    SciTech Connect (OSTI)

    Zhou, Z.; Rainforth, W. M.; Gass, M. H.; Bleloch, A.; Ehiassarian, A. P.; Hovsepian, P. Eh.

    2011-10-01

    CrC with the fcc NaCl (B1) structure is a metastable phase that can be obtained under the non-equilibrium conditions of high ion irradiation. A nano-composite coating consisting of amorphous carbon embedded in a CrC matrix was prepared via the unbalanced magnetron sputtering of graphite and Cr metal targets in Ar gas with a high ionized flux (ion-to-neutral ratio Ji/Jn = 6). The nanoscale amorphous carbon clusters self-assembled into layers alternated by CrC, giving the composite a multilayer structure. The phase, microstructure, and composition of the coating were characterized using x-ray diffraction, transmission electron microscopy, and aberration corrected scanning transmission electron microscopy coupled with electron energy loss spectroscopy. The interpretation of the true coating structure, in particular the carbide type, is discussed.

  4. Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

    SciTech Connect (OSTI)

    Cutting, R. S.; Coker, V. S.; Telling, N. D.; Kimber, R. L.; Pearce, C. I.; Ellis, B.; Lawson, R; van der Laan, G.; Pattrick, R.A.D.; Vaughan, D.J.; Arenholz, E.; Lloyd, J. R.

    2009-09-09

    To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe{sub 3}O{sub 4} powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticle surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion ({approx}10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a {gamma}-camera to obtain real time images of a {sup 99m}Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more ({approx}20%) {sup 99m}Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral substrate

  5. Audit Report: CR-B-97-03 | Department of Energy

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

    3 Audit Report: CR-B-97-03 May 6, 1997 Followup Audit on the Procurement of Support Services for the Energy Information Administration Audit Report: CR-B-97-03 (58.94 KB) More Documents & Publications Aligning Contract Incentives & Contract Mgt Trends - David Leotta, Director, Office of Contract Management, OAPM OPAM Policy Acquisition Guides Microsoft Word - AcqGuide16pt1 Nov 2010

  6. Heat treatment of NiCrFe alloy 600 to optimize resistance to intergranular stress corrosion

    DOE Patents [OSTI]

    Steeves, A.F.; Bibb, A.E.

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprises heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cooling the alloy body, and heating the cooled body to a temperature between 1100 to 1500/sup 0/F for about 1 to 30 hours.

  7. Heat treatment of NiCrFe alloy to optimize resistance to intergrannular stress corrosion

    DOE Patents [OSTI]

    Steeves, Arthur F.; Bibb, Albert E.

    1984-01-01

    A process of producing a NiCrFe alloy having a high resistance to stress corrosion cracking comprising heating a NiCrFe alloy to a temperature sufficient to enable the carbon present in the alloy body in the form of carbide deposits to enter into solution, rapidly cool the alloy body, and heat the cooled body to a temperature between 1100.degree. to 1500.degree. F. for about 1 to 30 hours.

  8. Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

    DOE Patents [OSTI]

    Park, Jong-Hee; Natesan, Krishnamurti; Rink, David L.

    2010-03-16

    An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

  9. Molecular beam epitaxy growth and magnetic properties of Cr-Co-Ga Heusler alloy films

    SciTech Connect (OSTI)

    Feng, Wuwei Wang, Weihua; Zhao, Chenglong; Van Quang, Nguyen; Cho, Sunglae; Dung, Dang Duc

    2015-11-15

    We have re-investigated growth and magnetic properties of Cr{sub 2}CoGa films using molecular beam epitaxy technique. Phase separation and precipitate formation were observed experimentally again in agreement with observation of multiple phases separation in sputtered Cr{sub 2}CoGa films by M. Meinert et al. However, significant phase separation could be suppressed by proper control of growth conditions. We showed that Cr{sub 2}CoGa Heusler phase, rather than Co{sub 2}CrGa phase, constitutes the majority of the sample grown on GaAs(001) at 450 {sup o}C. The measured small spin moment of Cr{sub 2}CoGa is in agreement with predicted HM-FCF nature; however, its Curie temperature is not as high as expected from the theoretical prediction probably due to the off-stoichiometry of Cr{sub 2}CoGa and the existence of the disorders and phase separation.

  10. Radiation Tolerance of Neutron-Irradiated Model Fe-Cr-Al Alloys

    SciTech Connect (OSTI)

    Field, Kevin G; Hu, Xunxiang; Littrell, Ken; Yamamoto, Yukinori; Snead, Lance Lewis

    2015-01-01

    The Fe Cr Al alloy system has the potential to form an important class of enhanced accident-tolerant cladding materials in the nuclear power industry owing to the alloy system's higher oxidation resistance in high-temperature steam environments compared with traditional zirconium-based alloys. However, radiation tolerance of Fe Cr Al alloys has not been fully established. In this study, a series of Fe Cr Al alloys with 10 18 wt % Cr and 2.9 4.9 wt % Al were neutron irradiated at 382 C to 1.8 dpa to investigate the irradiation-induced microstructural and mechanical property evolution as a function of alloy composition. Dislocation loops with Burgers vector of a/2 111 and a 100 were detected and quantified. Results indicate precipitation of Cr-rich is primarily dependent on the bulk chromium composition. Mechanical testing of sub-size-irradiated tensile specimens indicates the hardening response seen after irradiation is dependent on the bulk chromium composition. A structure property relationship was developed; it indicated that the change in yield strength after irradiation is caused by the formation of these radiation-induced defects and is dominated by the large number density of Cr-rich precipitates at sufficiently high chromium contents after irradiation.