National Library of Energy BETA

Sample records for oxidants study sos

  1. ARM - Field Campaign - 1995 Southern Oxidants Study (SOS)

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

    5 Southern Oxidants Study (SOS) ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : 1995 Southern Oxidants Study (SOS) 1995.06.24 - 1995.07.20 Lead Scientist : Peter Daum For data sets, see below. Abstract The cause and extent of elevated ozone levels that are often found during summer in the southeastern United States were the focus of the intensive Southern Oxidants Study (SOS) 1995 Nashville/Middle

  2. Sos Cuetara | Open Energy Information

    Open Energy Info (EERE)

    primarily engaged in the food sector. The Vegetable oils division is involved in the production and of seeds and olive oil. References: Sos Cuetara1 This article is a stub....

  3. PIC DOC 01/08/11 ? SOS

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

    PIC DOC 010811 - SOS Content Outline 1) Usable Quotes We shouldn't equate public involvement with meetings. Maynard Plahuta Meetings, of many kinds, are probably the most...

  4. Oxidation Resistant Graphite Studies

    SciTech Connect (OSTI)

    W. Windes; R. Smith

    2014-07-01

    The Very High Temperature Reactor (VHTR) Graphite Research and Development Program is investigating doped nuclear graphite grades exhibiting oxidation resistance. During a oxygen ingress accident the oxidation rates of the high temperature graphite core region would be extremely high resulting in significant structural damage to the core. Reducing the oxidation rate of the graphite core material would reduce the structural effects and keep the core integrity intact during any air-ingress accident. Oxidation testing of graphite doped with oxidation resistant material is being conducted to determine the extent of oxidation rate reduction. Nuclear grade graphite doped with varying levels of Boron-Carbide (B4C) was oxidized in air at nominal 740°C at 10/90% (air/He) and 100% air. The oxidation rates of the boronated and unboronated graphite grade were compared. With increasing boron-carbide content (up to 6 vol%) the oxidation rate was observed to have a 20 fold reduction from unboronated graphite. Visual inspection and uniformity of oxidation across the surface of the specimens were conducted. Future work to determine the remaining mechanical strength as well as graphite grades with SiC doped material are discussed.

  5. Studies on supported metal oxide-oxide support interactions ...

    Office of Scientific and Technical Information (OSTI)

    Subject: 36 MATERIALS SCIENCE; 66 PHYSICS; CERIUM OXIDES; SURFACE PROPERTIES; ALUMINIUM OXIDES; COPPER OXIDES; BINDING ENERGY; X-RAY DIFFRACTION; INFRARED SPECTRA; VALENCE; ZINC ...

  6. K-9 SOS receives small business award | Y-12 National Security Complex

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

    K-9 SOS receives small ... K-9 SOS receives small business award The mp4 video format is not supported by this browser. Download video Captions: On Time: 4:33 min. Consolidated Nuclear Security, LLC recently recognized small businesses who exemplified the absolutes of safety, security, quality, cost efficiency and mission delivery. Watch a video about one of the winners, K-9 Search on Site

  7. National Energy Technology Laboratory Publishes Solid Oxide Fuel Cell Studies

    Broader source: Energy.gov [DOE]

    A compilation of studies examining cathodes for solid oxide fuel cells is available on the Department of Energy’s National Energy Technology Laboratory website. The report, entitled Recent Solid Oxide Fuel Cell Cathode Studies, provides a concise, portfolio-wide synopsis of cathode research conducted under the Office of Fossil Energy’s Solid Oxide Fuel Cells Program.

  8. Excerpt from Steve Hudson's Summary HAB Advice and Committee Recommendations on SOS

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

    Steve Hudson's Summary HAB Advice and Committee Recommendations on SOS Dated 1/8/11, and shared again with PIC in April 2012 1 Persistent Core Principals * The public have a right to the information they need to make informed and responsible decisions about their future. * Those responsible for Hanford cleanup must provide a comprehensive and public accounting of activities, performance, and challenges related to the cleanup. * All persons affected by or interested in Hanford cleanup are

  9. Computational studies of polysiloxanes : oxidation potentials and decomposition reactions.

    SciTech Connect (OSTI)

    Assary, R. S.; Curtiss, L. A.; Redfern, P. C.; Zhang, Z.; Amine, K.

    2011-06-23

    Silicon-containing solvents have tremendous potential for application as electrolytes for electrical energy storage devices such as lithium-ion (air) batteries and supercapacitors. Quantum chemical methods were employed to investigate trends in oxidation potentials and decomposition reactions of a series of polysiloxanes. Various electron-donating and -withdrawing substituents can be used to tune the oxidation potential in shorter chain siloxanes but not in longer ones. Decomposition reactions of siloxanes in their oxidized states were investigated and compared against their carbon analogues. These studies suggest that the Si-O group provides added stability for siloxanes over their carbon analogues. Computational studies have also been performed for various disiloxanes and siloxanes with spacer groups to understand their thermochemical stability and oxidation potentials.

  10. Two-Step Annealing Study of Cuprous Oxide for Photovoltaic Application...

    Office of Scientific and Technical Information (OSTI)

    Two-Step Annealing Study of Cuprous Oxide for Photovoltaic Applications Citation Details In-Document Search Title: Two-Step Annealing Study of Cuprous Oxide for Photovoltaic ...

  11. Oxide

    SciTech Connect (OSTI)

    2014-07-15

    Oxide is a modular framework for feature extraction and analysis of executable files. Oxide is useful in a variety of reverse engineering and categorization tasks relating to executable content.

  12. Wide range modeling study of dimethyl ether oxidation

    SciTech Connect (OSTI)

    Pitz, W.J.; Marinov, N.M.; Westbrook, C.K.; Dagaut, P.; Boettner, J-C; Cathonnet, M.

    1997-04-01

    A detailed chemical kinetic model has been used to study dimethyl ether (DME) oxidation over a wide range of conditions. Experimental results obtained in a jet-stirred reactor (JSR) at I and 10 atm, 0.2 < 0 < 2.5, and 800 < T < 1300 K were modeled, in addition to those generated in a shock tube at 13 and 40 bar, 0 = 1.0 and 650 :5 T :5 1300 K. The JSR results are particularly valuable as they include concentration profiles of reactants, intermediates and products pertinent to the oxidation of DME. These data test the Idnetic model severely, as it must be able to predict the correct distribution and concentrations of intermediate and final products formed in the oxidation process. Additionally, the shock tube results are very useful, as they were taken at low temperatures and at high pressures, and thus undergo negative temperature dependence (NTC) behavior. This behavior is characteristic of the oxidation of saturated hydrocarbon fuels, (e.g. the primary reference fuels, n-heptane and iso- octane) under similar conditions. The numerical model consists of 78 chemical species and 336 chemical reactions. The thermodynamic properties of unknown species pertaining to DME oxidation were calculated using THERM.

  13. Physical and electrochemical study of cobalt oxide nano- and microparticles

    SciTech Connect (OSTI)

    Alburquenque, D.; Vargas, E.; Denardin, J.C.; Escrig, J.; Marco, J.F.; Gautier, J.L.

    2014-07-01

    Cobalt oxide nanocrystals of size 17–21 nm were synthesized by a simple reaction between cobalt acetate (II) and dodecylamine. On the other hand, micrometric Co{sub 3}O{sub 4} was prepared using the ceramic method. The structural examination of these materials was performed using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM and HRTEM). XRD studies showed that the oxides were pure, well-crystallized, spinel cubic phases with a-cell parameter of 0.8049 nm and 0.8069 nm for the nano and micro-oxide, respectively. The average particle size was 19 nm (nano-oxide) and 1250 μm (micro-oxide). Morphological studies carried out by SEM and TEM analyses have shown the presence of octahedral particles in both cases. Bulk and surface properties investigated by X-ray photoelectron spectroscopy (XPS), point zero charge (pzc), FTIR and cyclic voltammetry indicated that there were no significant differences in the composition on both materials. The magnetic behavior of the samples was determined using a vibrating sample magnetometer. The compounds showed paramagnetic character and no coercivity and remanence in all cases. Galvanostatic measurements of electrodes formed with nanocrystals showed better performance than those built with micrometric particles. - Highlights: • Spinel Co{sub 3}O{sub 4} nanoparticles and microparticles with same structure but with different cell parameters, particle size and surface area were synthesized. • Oxide nanoparticles showed better electrochemical behavior than micrometric ones due to area effect.

  14. Kinetic study of the oxidation of n-butane on vanadium oxide supported on Al/Mg mixed oxide

    SciTech Connect (OSTI)

    Dejoz, A.; Vazquez, I.; Nieto, J.M.L.; Melo, F.

    1997-07-01

    The reaction kinetics of the oxidative dehydrogenation (ODH) of n-butane over vanadia supported on a heat-treated Mg/Al hydrotalcite (37.3 wt % of V{sub 2}O{sub 5}) was investigated by both linear and nonlinear regression techniques. A reaction network including the formation of butenes (1-, 2-cis-, and 2-trans-butene), butadiene, and carbon oxides by parallel and consecutive reactions, at low and high n-butane conversions, has been proposed. Langmuir-Hinshelwood (LH) models can be used as suitable models which allows reproduction of the global kinetic behavior, although differences between oxydehydrogenation and deep oxidation reactions have been observed. Thus, the formation of oxydehydrogenation products can be described by a LH equation considering a dissociative adsorption of oxygen while the formation of carbon oxides is described by a LH equation with a nondissociative adsorption of oxygen. Two different mechanisms operate on the catalyst: (i) a redox mechanism responsible of the formation of olefins and diolefins and associated to vanadium species, which is initiated by a hydrogen abstraction; (ii) a radical mechanism responsible of the formation of carbon oxides from n-butane and butenes and associated to vanadium-free sites of the support. On the other hand, the selectivity to oxydehydrogenation products increases with the reaction temperature. This catalytic performance can be explained taking into account the low reducibility of V{sup 5+}-sites and the higher apparent activation energies of the oxydehydrogenation reactions with respect to deep oxidation reactions.

  15. Studies on nickel-tungsten oxide thin films

    SciTech Connect (OSTI)

    Usha, K. S.; Sivakumar, R.; Sanjeeviraja, C.

    2014-10-15

    Nickel-Tungsten oxide (95:5) thin films were prepared by rf sputtering at 200W rf power with various substrate temperatures. X-ray diffraction study reveals the amorphous nature of films. The substrate temperature induced decrease in energy band gap with a maximum transmittance of 71%1 was observed. The Micro-Raman study shows broad peaks at 560 cm{sup −1} and 1100 cm{sup −1} correspond to Ni-O vibration and the peak at 860 cm{sup −1} can be assigned to the vibration of W-O-W bond. Photoluminescence spectra show two peaks centered on 420 nm and 485 nm corresponding to the band edge emission and vacancies created due to the addition of tungsten, respectively.

  16. Pseudopotentials for quantum Monte Carlo studies of transition metal oxides

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

    Krogel, Jaron T.; Santana Palacio, Juan A.; Reboredo, Fernando A.

    2016-02-22

    Quantum Monte Carlo (QMC) calculations of transition metal oxides are partially limited by the availability of high-quality pseudopotentials that are both accurate in QMC and compatible with major plane-wave electronic structure codes. We have generated a set of neon-core pseudopotentials with small cutoff radii for the early transition metal elements Sc to Zn within the local density approximation of density functional theory. The pseudopotentials have been directly tested for accuracy within QMC by calculating the first through fourth ionization potentials of the isolated transition metal (M) atoms and the binding curve of each M-O dimer. We find the ionization potentialsmore » to be accurate to 0.16(1) eV, on average, relative to experiment. The equilibrium bond lengths of the dimers are within 0.5(1)% of experimental values, on average, and the binding energies are also typically accurate to 0.18(3) eV. The level of accuracy we find for atoms and dimers is comparable to what has recently been observed for bulk metals and oxides using the same pseudopotentials. Our QMC pseudopotential results compare well with the findings of previous QMC studies and benchmark quantum chemical calculations.« less

  17. Transgenic evaluation of activated mutant alleles of SOS2 reveals a critical requirement for its kinase activity and C-terminal regulatory domain for salt tolerance in Arabidopsis thaliana

    DOE Patents [OSTI]

    Zhu, Jian-Kang; Quintero-Toscano, Francisco Javier; Pardo-Prieto, Jose Manuel; Qiu, Quansheng; Schumaker, Karen Sue; Ohta, Masaru; Zhang, Changqing; Guo, Yan

    2007-09-04

    The present invention provides a method of increasing salt tolerance in a plant by overexpressing a gene encoding a mutant SOS2 protein in at least one cell type in the plant. The present invention also provides for transgenic plants expressing the mutant SOS2 proteins.

  18. Self-irradiation and oxidation effects on americium sesquioxide and Raman spectroscopy studies of americium oxides

    SciTech Connect (OSTI)

    Horlait, Denis; Delahaye, Thibaud

    2014-09-15

    Americium oxides samples were characterized by X-ray diffraction (XRD) and Raman spectroscopy, with an emphasis on their structural behavior under oxidation and self-irradiation. Raman spectra of americium dioxide (AmO{sub 2}) and sesquioxide (Am{sub 2}O{sub 3}) were obtained for the first time. With the help of literature data on isostructural oxides, Raman signatures of Ia-3 C-type Am{sub 2}O{sub 3} and P-3m1 A-type Am{sub 2}O{sub 3} are identified. For AmO{sub 2,} a clear band is noted at 390 cm{sup −1}. Its nature is compared to that of the other actinide dioxides. Am{sub 2}O{sub 3} evolution under ambient conditions and against {sup 241}Am α self-irradiation was monitored by powder XRD. The sample, initially composed of A-type Am{sub 2}O{sub 3} as major phase as well as C2/m B-type and C-type structures as minor phases, progressively oxidizes to Fm-3m AmO{sub 2−δ} over a few months. On the basis of diffractogram refinements, evolutions of unit cell volumes caused by self-irradiation are also determined and discussed. - Graphical abstract: The evolution of americium oxide under ambient conditions was monitored using XRD (X-ray diffraction) and Raman spectroscopy. After a thermal treatment under reducing conditions, a polyphasic sample mainly composed of A- and C-type americium sesquioxides is evidenced by XRD and Raman spectroscopy. The sample then evolves through two processes: oxidation and self-irradiation. The first one provokes the progressive appearance of F-type americium dioxide while the initial phases disappear, whereas the main effect of the second is a structural swelling with time. - Highlights: • The first Raman spectroscopy measurements on americium oxides were performed. • Observed Am{sub 2}O{sub 3} Raman bands were identified thanks to data on analogue compounds. • AmO{sub 2} assumed T{sub 2g} band presents a shift compared to the actinide dioxide series. • Am{sub 2}O{sub 3} evolution under self-irradiation and oxidation was also

  19. Soft X-ray Spectroscopy Study of the Electronic Structure of Oxidized and Partially Oxidized Magnetite Nanoparticles

    SciTech Connect (OSTI)

    Gilbert, Benjamin; Katz, Jordan E.; Denlinger, Jonathan D.; Yin, Yadong; Falcone, Roger; Waychunas, Glenn A.

    2010-10-24

    The crystal structure of magnetite nanoparticles may be transformed to maghemite by complete oxidation, but under many relevant conditions the oxidation is partial, creating a mixed-valence material with structural and electronic properties that are poorly characterized. We used X-ray diffraction, Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, and soft X-ray absorption and emission spectroscopy to characterize the products of oxidizing uncoated and oleic acid-coated magnetite nanoparticles in air. The oxidization of uncoated magnetite nanoparticles creates a material that is structurally and electronically indistinguishable from maghemite. By contrast, while oxidized oleic acid-coated nanoparticles are also structurally indistinguishable from maghemite, Fe L-edge spectroscopy revealed the presence of interior reduced iron sites even after a 2-year period. We used X-ray emission spectroscopy at the O K-edge to study the valence bands (VB) of the iron oxide nanoparticles, using resonant excitation to remove the contributions from oxygen atoms in the ligands and from low-energy excitations that obscured the VB edge. The bonding in all nanoparticles was typical of maghemite, with no detectable VB states introduced by the long-lived, reduced-iron sites in the oleic acid-coated sample. However, O K-edge absorption spectroscopy observed a 0.2 eV shift in the position of the lowest unoccupied states in the coated sample, indicating an increase in the semiconductor band gap relative to bulk stoichiometric maghemite that was also observed by optical absorption spectroscopy. The results show that the ferrous iron sites within ferric iron oxide nanoparticles coated by an organic ligand can persist under ambient conditions with no evidence of a distinct interior phase and can exert an effect on the global electronic and optical properties of the material. This phenomenon resembles the band gap enlargement caused by electron accumulation in the

  20. Development studies of a novel wet oxidation process

    SciTech Connect (OSTI)

    Rogers, T.W.; Dhooge, P.M.

    1995-10-01

    Many DOE waste streams and remediates contain complex and variable mixtures of organic compounds, toxic metals, and radionuclides. These materials are often dispersed in organic or inorganic matrices, such as personal protective equipment, various sludges, soils, and water. Incineration and similar combustive processes do not appear to be viable options for treatment of these waste streams due to various considerations. The objective of this project is to develop a novel catalytic wet oxidation process for the treatment of multi-component wastes. The DETOX process uses a unique combination of metal catalysts to increase the rate of oxidation of organic materials.

  1. Photoemission spectroscopy study of the lanthanum lutetium oxide/silicon interface

    SciTech Connect (OSTI)

    Nichau, A.; Schnee, M.; Schubert, J.; Bernardy, P.; Hollaender, B.; Buca, D.; Mantl, S.; Besmehn, A.; Breuer, U.; Rubio-Zuazo, J.; Castro, G. R.; Muecklich, A.; Borany, J. von

    2013-04-21

    Rare earth oxides are promising candidates for future integration into nano-electronics. A key property of these oxides is their ability to form silicates in order to replace the interfacial layer in Si-based complementary metal-oxide field effect transistors. In this work a detailed study of lanthanum lutetium oxide based gate stacks is presented. Special attention is given to the silicate formation at temperatures typical for CMOS processing. The experimental analysis is based on hard x-ray photoemission spectroscopy complemented by standard laboratory experiments as Rutherford backscattering spectrometry and high-resolution transmission electron microscopy. Homogenously distributed La silicate and Lu silicate at the Si interface are proven to form already during gate oxide deposition. During the thermal treatment Si atoms diffuse through the oxide layer towards the TiN metal gate. This mechanism is identified to be promoted via Lu-O bonds, whereby the diffusion of La was found to be less important.

  2. Further studies of the effects of oxidation on the surface properties of coal and coal pyrite

    SciTech Connect (OSTI)

    Herrera, M.N.

    1994-12-31

    The objective of this research was to investigate the oxidation behavior of coal and coal pyrite and to correlate the changes in the surface properties induced by oxidation, along with the intrinsic physical and chemical properties of these organic and inorganic materials, with the behavior in physical coal cleaning processes. This provide more fundamental knowledge for understanding the way in which different factors interact in a medium as heterogeneous as coal. Fourteen coal samples of different ranks ranging from high to medium sulfur content were studied by dry oxidation tests at different temperatures and humidities, and by wet oxidation tests using different oxidizing agents. The concentration of surface oxygen functional groups was determined by ion-exchange methods. The changes in the coal composition with oxidation were analyzed by spectroscopic techniques. The wettability of as-received and oxidized coal and coal pyrite samples was assessed by film flotation tests. The electrokinetic behavior of different coals and coal pyrite samples was studied by electrokinetic tests using electrophoresis. Possible oxidation mechanisms have been proposed to explain the changes on the coal surface induced by different oxidation treatments.

  3. Operando NMR and XRD study of chemically synthesized LiCx oxidation...

    Office of Scientific and Technical Information (OSTI)

    Title: Operando NMR and XRD study of chemically synthesized LiCx oxidation in a dry room environment We test the stability of pre-lithiated graphite anodes for Li-ion batteries in ...

  4. Structure of crystalline oxide ceramics studied by phonon spectroscopy

    SciTech Connect (OSTI)

    Kaminskii, Alexandr A; Taranov, A V; Khazanov, E N

    2013-03-31

    This paper describes a method for gaining detailed insight into the structure and phonon spectrum of polycrystalline oxide ceramics. We examine how the diffusion coefficient of subterahertz phonons is related to the properties of a system of grain boundaries and to the grain size and structure and demonstrate that the temperature dependence of the phonon diffusion coefficient at liquid-helium temperatures is determined by the spectral properties of the intergranular layer, which allows one to estimate the volumeaveraged intergranular layer thickness and acoustic impedance. We also analyse the effect of plastic deformation via twinning on the formation of the structure of grains and intergranular layers, which determine the thermophysical, acoustic and optical properties of ceramic materials. (extreme light fields and their applications)

  5. Growth Mode Transition in Complex Oxide Heteroepitaxy: Atomically Resolved Studies

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

    Tselev, Alexander; Vasudevan, Rama K.; Gianfrancesco, Anthony G.; Qiao, Liang; Meyer, Tricia L.; Lee, Ho Nyung; Biegalski, Michael D.; Baddorf, Arthur P.; Kalinin, Sergei V.

    2016-04-04

    Here we performed investigations of the atomic-scale surface structure of epitaxial La5/8Ca3/8MnO3 thin films as a model system dependent on growth conditions in pulsed laser deposition with emphasis on film growth kinetics. Postdeposition in situ scanning tunneling microscopy was combined with in operando reflective high-energy electron diffraction to monitor the film growth and ex situ X-ray diffraction for structural analysis. We find a correlation between the out-of-plane lattice parameter and both adspecies mobility and height of the Ehrlich–Schwoebel barrier, with mobility of adatoms greater over the cationically stoichiometric terminations. We find that the data suggest that the out-of-plane lattice parametermore » is dependent on the mechanism of epitaxial strain relaxation, which is controlled by the oxidative power of the deposition environment.« less

  6. Transpiring wall supercritical water oxidation reactor salt deposition studies

    SciTech Connect (OSTI)

    Haroldsen, B.L.; Mills, B.E.; Ariizumi, D.Y.; Brown, B.G.

    1996-09-01

    Sandia National Laboratories has teamed with Foster Wheeler Development Corp. and GenCorp, Aerojet to develop and evaluate a new supercritical water oxidation reactor design using a transpiring wall liner. In the design, pure water is injected through small pores in the liner wall to form a protective boundary layer that inhibits salt deposition and corrosion, effects that interfere with system performance. The concept was tested at Sandia on a laboratory-scale transpiring wall reactor that is a 1/4 scale model of a prototype plant being designed for the Army to destroy colored smoke and dye at Pine Bluff Arsenal in Arkansas. During the tests, a single-phase pressurized solution of sodium sulfate (Na{sub 2}SO{sub 4}) was heated to supercritical conditions, causing the salt to precipitate out as a fine solid. On-line diagnostics and post-test observation allowed us to characterize reactor performance at different flow and temperature conditions. Tests with and without the protective boundary layer demonstrated that wall transpiration provides significant protection against salt deposition. Confirmation tests were run with one of the dyes that will be processed in the Pine Bluff facility. The experimental techniques, results, and conclusions are discussed.

  7. Isotopic Studies of O-O Bond Formation During Water Oxidation (SISGR)

    SciTech Connect (OSTI)

    Roth, Justine P.

    2015-03-03

    Isotopic Studies of O-O Bond Formation During Water Oxidation (SISGR) Research during the project period focused primarily on mechanisms of water oxidation by structurally defined transition metal complexes. Competitive oxygen isotope fractionation of water, mediated by oxidized precursors or reduced catalysts together with ceric, Ce(IV), ammonium nitrate in aqueous media, afforded oxygen-18 kinetic isotope effects (O-18 KIEs). Measurement, calculation, and interpretation of O-18 KIEs, described in the accompanying report has important ramifications for the production of electricity and solar hydrogen (as fuel). The catalysis division of BES has acknowledged that understanding mechanisms of transition metal catalyzed water oxidation has major ramifications, potentially leading to transformation of the global economy and natural environment in years to come. Yet, because of program restructuring and decreased availability of funds, it was recommended that the Solar Photochemistry sub-division of BES would be a more appropriate parent program for support of continued research.

  8. Palladium nanoparticles anchored on graphene nanosheets: Methanol, ethanol oxidation reactions and their kinetic studies

    SciTech Connect (OSTI)

    Nagaraju, D.H.; Devaraj, S.; Balaya, P.

    2014-12-15

    Highlights: • Palladium nanoparticles decorated graphene is synthesized in a single step. • Electro-catalytic activity of Gra/Pd toward alcohol oxidation is evaluated. • 1:1 Gra/Pd exhibits good electro-catalytic activity and efficient electron transfer. - Abstract: Palladium nanoparticles decorated graphene (Gra/Pd nanocomposite) was synthesized by simultaneous chemical reduction of graphene oxide and palladium salt in a single step. The negatively charged graphene oxide (GO) facilitates uniform distribution of Pd{sup 2+} ions onto its surface. The subsequent reduction by hydrazine hydrate provides well dispersed Pd nanoparticles decorated graphene. Different amount of Pd nanoparticles on graphene was synthesized by changing the volume to weight ratio of GO to PdCl{sub 2}. X-ray diffraction studies showed FCC lattice of Pd with predominant (1 1 1) plane. SEM and TEM studies revealed that thin graphene nanosheets are decorated by Pd nanoparticles. Raman spectroscopic studies revealed the presence of graphene nanosheets. The electro-catalytic activity of Gra/Pd nanocomposites toward methanol and ethanol oxidation in alkaline medium was evaluated by cyclic voltammetric studies. 1:1 Gra/Pd nanocomposite exhibited good electro-catalytic activity and efficient electron transfer. The kinetics of electron transfer was studied using chronoamperometry. Improved electro-catalytic activity of 1:1 Gra/Pd nanocomposite toward alcohol oxidation makes it as a potential anode for the alcohol fuel cells.

  9. Studies on Oxide Cathode Crystals | Department of Energy

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

    Energy 3 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting es106_nanda_2013_o.pdf (2.38 MB) More Documents & Publications Vehicle Technologies Office Merit Review 2014: Electrochemical Modeling of LMR-NMC Materials and Electrodes Vehicle Technologies Office Merit Review 2014: Studies on High Capacity Cathodes for Advanced Lithium-ion Systems Engineering of High Energy Cathode Materials

    es069_chen_2011_o.pdf (5.27 MB)

  10. Longitudinal study of children exposed to sulfur oxides

    SciTech Connect (OSTI)

    Dodge, R.; Solomon, P.; Moyers, J.; Hayes, C.

    1985-05-01

    This study is a longitudinal comparison of the health of children exposed to markedly different concentrations of sulfur dioxide and moderately different concentrations of particulate sulfate. The four groups of subjects lived in two areas of one smelter town and in two other towns, one of which was also a smelter town. In the area of highest pollution, children were intermittently exposed to high SO/sub 2/ levels (peak three-hour average concentration exceeded 2,500 micrograms/m3) and moderate particulate SO/sub 4/= levels (average concentration was 10.1 micrograms/m3). When the children were grouped by the four gradients of pollution observed, the prevalence of cough (measured by questionnaire) correlated significantly with pollution levels (trend chi-square = 5.6, p = 0.02). No significant differences in the incidence of cough or other symptoms occurred among the groups of subjects over three years, and pulmonary function and lung function growth over the study were roughly equal among all the groups. These results suggest that intermittent elevations in SO/sub 2/ concentration, in the presence of moderate particulate SO/sub 4/= concentration, produced evidence of bronchial irritation in the subjects, but no chronic effect on lung function or lung function growth was detected.

  11. Structural, electronic, mechanical, and dynamical properties of graphene oxides: A first principles study

    SciTech Connect (OSTI)

    Dabhi, Shweta D.; Gupta, Sanjay D.; Jha, Prafulla K.

    2014-05-28

    We report the results of a theoretical study on the structural, electronic, mechanical, and vibrational properties of some graphene oxide models (GDO, a-GMO, z-GMO, ep-GMO and mix-GMO) at ambient pressure. The calculations are based on the ab-initio plane-wave pseudo potential density functional theory, within the generalized gradient approximations for the exchange and correlation functional. The calculated values of lattice parameters, bulk modulus, and its first order pressure derivative are in good agreement with other reports. A linear response approach to the density functional theory is used to derive the phonon frequencies. We discuss the contribution of the phonons in the dynamical stability of graphene oxides and detailed analysis of zone centre phonon modes in all the above mentioned models. Our study demonstrates a wide range of energy gap available in the considered models of graphene oxide and hence the possibility of their use in nanodevices.

  12. Detailed kinetic modeling study of n-pentanol oxidation

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

    Heufer, K. Alexander; Sarathy, S. Mani; Curran, Henry J.; Davis, Alexander C.; Westbrook, Charles K.; Pitz, William J.

    2012-09-28

    To help overcome the world’s dependence upon fossil fuels, suitable biofuels are promising alternatives that can be used in the transportation sector. Recent research on internal combustion engines shows that short alcoholic fuels (e.g., ethanol or n-butanol) have reduced pollutant emissions and increased knock resistance compared to fossil fuels. Although higher molecular weight alcohols (e.g., n-pentanol and n-hexanol) exhibit higher reactivity that lowers their knock resistance, they are suitable for diesel engines or advanced engine concepts, such as homogeneous charge compression ignition (HCCI), where higher reactivity at lower temperatures is necessary for engine operation. The present study presents a detailedmore » kinetic model for n-pentanol based on modeling rules previously presented for n-butanol. This approach was initially validated using quantum chemistry calculations to verify the most stable n-pentanol conformation and to obtain C–H and C–C bond dissociation energies. In addition, the proposed model has been validated against ignition delay time data, speciation data from a jet-stirred reactor, and laminar flame velocity measurements. Overall, the model shows good agreement with the experiments and permits a detailed discussion of the differences between alcohols and alkanes.« less

  13. FUNDAMENTAL STUDIES OF THE DURABILITY OF MATERIALS FOR INTERCONNECTS IN SOLID OXIDE FUEL CELLS

    SciTech Connect (OSTI)

    Frederick S. Pettit; Gerald H. Meier

    2003-06-30

    This report describes the result of the first eight months of effort on a project directed at improving metallic interconnect materials for solid oxide fuel cells (SOFCs). The results include cyclic oxidation studies of a group of ferritic alloys, which are candidate interconnect materials. The exposures have been carried out in simulated fuel cell atmospheres. The oxidation morphologies have been characterized and the ASR has been measured for the oxide scales. The effect of fuel cell electric current density on chromia growth rates has been considered The thermomechanical behavior of the scales has been investigated by stress measurements using x-ray diffraction and interfacial fracture toughness measurements using indentation. The ultimate goal of this thrust is to use knowledge of changes in oxide thickness, stress and adhesion to develop accelerated testing methods for evaluating SOFC interconnect alloys. Finally a theoretical assessment of the potential for use of ''new'' metallic materials as interconnect materials has been conducted and is presented in this report. Alloys being considered include materials based on pure nickel, materials based on the ''Invar'' concept, and coated materials to optimize properties in both the anode and cathode gases.

  14. Fundamental Studies of the Durability of Materials for Interconnects in Solid Oxide Fuel Cells

    SciTech Connect (OSTI)

    Frederick S. Pettit; Gerald H. Meier

    2006-06-30

    Ferritic stainless steels are a leading candidate material for use as an SOFC interconnect, but have the problem of forming volatile chromia species that lead to cathode poisoning. This project has focused both on optimization of ferritic alloys for SOFC applications and evaluating the possibility of using alternative materials. The initial efforts involved studying the oxidation behavior of a variety of chromia-forming ferritic stainless steels in the temperature range 700-900 C in atmospheres relevant to solid oxide fuel cell operation. The alloys exhibited a wide variety of oxidation behavior based on composition. A method for reducing the vaporization is to add alloying elements that lead to the formation of a thermally grown oxide layer over the protective chromia. Several commercial steels form manganese chromate on the surface. This same approach, combined with observations of TiO{sub 2} overlayer formation on the chromia forming, Ni-based superalloy IN 738, has resulted in the development of a series of Fe-22 Cr-X Ti alloys (X=0-4 wt%). Oxidation testing has indicated that this approach results in significant reduction in chromia evaporation. Unfortunately, the Ti also results in accelerated chromia scale growth. Fundamental thermo-mechanical aspects of the durability of solid oxide fuel cell (SOFC) interconnect alloys have also been investigated. A key failure mechanism for interconnects is the spallation of the chromia scale that forms on the alloy, as it is exposed to fuel cell environments. Indentation testing methods to measure the critical energy release rate (Gc) associated with the spallation of chromia scale/alloy systems have been evaluated. This approach has been used to evaluate the thermomechanical stability of chromia films as a function of oxidation exposure. The oxidation of pure nickel in SOFC environments was evaluated using thermogravimetric analysis (TGA) to determine the NiO scaling kinetics and a four-point probe was used to measure

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

    SciTech Connect (OSTI)

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

    1998-01-01

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

  16. Pyroprocessing of Oxidized Sodium-Bonded Fast Reactor Fuel -- an Experimental Study of Treatment Options for Degraded EBR-II Fuel

    SciTech Connect (OSTI)

    S. D. Herrmann; L. A. Wurth; N. J. Gese

    2013-09-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electrometallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li2O at 650 C with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. The experimental study illustrated how zirconium oxide and sodium oxide present different challenges to a lithium-based electrolytic reduction system for conversion of select metal oxides to metal.

  17. Uranium Immobilization through Fe(II) bio-oxidation: A Column study

    SciTech Connect (OSTI)

    Coates, John D.

    2009-09-14

    Current research on the bioremediation of heavy metals and radionuclides is focused on the ability of reducing organisms to use these metals as alternative electron acceptors in the absence of oxygen and thus precipitate them out of solution. However, many aspects of this proposed scheme need to be resolved, not the least of which is the time frame of the treatment process. Once treatment is complete and the electron donor addition is halted, the system will ultimately revert back to an oxic state and potentially result in the abiotic reoxidation and remobilization of the immobilized metals. In addition, the possibility exists that the presence of more electropositive electron acceptors such as nitrate or oxygen will also stimulate the biological oxidation and remobilization of these contaminants. The selective nitrate-dependent biooxidation of added Fe(II) may offer an effective means of capping off and completing the attenuation of these contaminants in a reducing environment making the contaminants less accessible to abiotic and biotic reactions and allowing the system to naturally revert to an oxic state. Our previous DOE-NABIR funded studies demonstrated that radionuclides such as uranium and cobalt are rapidly removed from solution during the biogenic formation of Fe(III)-oxides. In the case of uranium, X-ray spectroscopy analysis indicated that the uranium was in the hexavalent form (normally soluble) and was bound to the precipitated Fe(III)-oxides thus demonstrating the bioremediative potential of this process. We also demonstrated that nitrate-dependent Fe(II)- oxidizing bacteria are prevalent in the sediment and groundwater samples collected from sites 1 and 2 and the background site of the NABIR FRC in Oakridge, TN. However, all of these studies were performed in batch experiments in the laboratory with pure cultures and although a significant amount was learned about the microbiology of nitrate-dependent bio-oxidation of Fe(II), the effects of

  18. Transient FTIR studies of the reaction pathway for n-butane selective oxidation over vanadyl pyrophosphate

    SciTech Connect (OSTI)

    Xue, Z.Y.; Schrader, G.L.

    1999-05-15

    New information has been provided about the reaction pathway for n-butane partial oxidation to maleic anhydride over vanadyl pyrophosphate (VPO) catalysts using FTIR spectroscopy under transient conditions. Adsorption studies of n-butane, 1,3-butadiene, and related oxygenates were performed to gain information about reaction intermediates. n-Butane was found to adsorb on the VPO catalyst to form olefinic species at low temperatures. Unsaturated, noncyclic carbonyl species were determined to be precursors to maleic anhydride.

  19. Shock-tube and modeling study of ethane pyrolysis and oxidation

    SciTech Connect (OSTI)

    Hidaka, Yoshiaki; Sato, Kazutaka; Hoshikawa, Hiroki; Nishimori, Toshihide; Takahashi, Rie; Tanaka, Hiroya; Inami, Koji; Ito, Nobuhiro

    2000-02-01

    Pyrolysis and oxidation of ethane were studied behind reflected shock waves in the temperature range 950--1,900 K at pressures of 1.2--4.0 atm. Ethane decay rates in both pyrolysis and oxidation were measured using time-resolved infrared (IR) laser absorption at 3.39 {micro}m, and CO{sub 2} production rates in oxidation were measured by time-resolved thermal IR emission at 4.24 {micro}m. The product yields were also determined using a single-pulse method. The pyrolysis and oxidation of ethane were modeled using a reaction mechanism with 157 reaction steps and 48 species including the most recent submechanisms for formaldehyde, ketene, methane, acetylene, and ethylene oxidation. The present and previously reported shock tube data were reproduced using this mechanism. The rate constants of the reactions C{sub 2}H{sub 6} {yields} CH{sub 3} + CH{sub 3}, C{sub 2}H{sub 5} + H {yields} H{sub 2} and C{sub 2}H{sub 5} + O{sub 2} {yields} C{sub 2}H{sub 4} + HO{sub 2} were evaluated. These reactions were important in predicting the previously reported and the present data, which were for mixture compositions ranging from ethane-rich (including ethane pyrolysis) to ethane-lean. The evaluated rate constants of the reactions C{sub 2}H{sub 5} + H {yields} C{sub 2}H{sub 4} + H{sub 2} and C{sub 2}H{sub 5} + O{sub 2} {yields} C{sub 2}H{sub 4} + HO{sub 2} were found to be significantly different from currently accepted values.

  20. X-Ray Absorption Studies of Vanadium-Containing Metal Oxide Nanocrystals

    SciTech Connect (OSTI)

    Hohn, Keith, L.

    2006-01-09

    Metal oxide nanocrystals offer significant potential for use as catalysts or catalyst supports due to their high surface areas and unique chemical properties that result from the high number of exposed corners and edges. However, little is known about the catalytic activity of these materials, especially as oxidation catalysts. This research focused on the preparation, characterization and use of vanadium-containing nanocrystals as selective oxidation catalysts. Three vanadium-containing nanocrystals were prepared using a modified sol-gel procedure: V/MgO, V/SiO2, and vanadium phosphate (VPO). These represent active oxidation catalysts for a number of industrially relevant reactions. The catalysts were characterized by x-ray diffraction and Raman, UV-VIS, infrared and x-ray absorption spectroscopies with the goal of determining the primary structural and chemical differences between nanocrystals and microcrystals. The catalytic activity of these catalysts was also studied in oxidative dehydrogenation of butane and methanol oxidation to formaldehyde. V/MgO nanocrystals were investigated for activity in oxidative dehydrogenation of butane and compared to conventional V/MgO catalysts. Characterization of V/MgO catalysts using Raman spectroscopy and x-ray absorption spectroscopy showed that both types of catalysts contained magnesium orthovanadate at vanadium loadings below 15 weight%, but above that loading, magnesium pyrovanadate may have been present. In general, MgO nanocrystals had roughly half the crystal size and double the surface area of the conventional MgO. In oxidative dehydrogenation of butane, nanocrystalline V/MgO gave higher selectivity to butene than conventional V/MgO at the same conversion. This difference was attributed to differences in vanadium domain size resulting from the higher surface areas of the nanocrystalline support, since characterization suggested that similar vanadium phases were present on both types of catalysts. Experiments in

  1. Surface and interfacial reaction study of InAs(100)-crystalline oxide interface

    SciTech Connect (OSTI)

    Zhernokletov, D. M.; Laukkanen, P.; Dong, H.; Brennan, B.; Kim, J.; Galatage, R. V.; Yakimov, M.; Tokranov, V.; Oktyabrsky, S.; Wallace, R. M.; Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080

    2013-05-27

    A crystalline oxide film on InAs(100) is investigated with in situ monochromatic x-ray photoelectron spectroscopy and low energy electron diffraction before and after in situ deposition of Al{sub 2}O{sub 3} by atomic layer deposition (ALD) as well as upon air exposure. The oxidation process leads to arsenic and indium trivalent oxidation state formation. The grown epitaxial oxide-InAs interface is stable upon ALD reactor exposure; however, trimethyl aluminum decreases oxidation states resulting in an unreconstructed surface. An increase in oxide concentration is also observed upon air exposure suggesting the crystalline oxide surface is unstable.

  2. Experimental study of the oxidation of methyl oleate in a jet-stirred reactor

    SciTech Connect (OSTI)

    Bax, Sarah; Hakka, Mohammed Hichem; Glaude, Pierre-Alexandre; Herbinet, Olivier; Battin-Leclerc, Frederique

    2010-06-15

    The experimental study of the oxidation of a blend containing n-decane and a large unsaturated ester, methyl oleate, was performed in a jet-stirred reactor over a wide range of temperature covering both low and high temperature regions (550-1100 K), at a residence time of 1.5 s, at quasi atmospheric pressure with high dilution in helium (n-decane and methyl oleate inlet mole fractions of 1.48 x 10{sup -3} and 5.2 x 10{sup -4}) and under stoichiometric conditions. The formation of numerous reaction products was observed. At low and intermediate temperatures, the oxidation of the blend led to the formation of species containing oxygen atoms like cyclic ethers, aldehydes and ketones deriving from n-decane and methyl oleate. At higher temperature, these species were not formed anymore and the presence of unsaturated species was observed. Because of the presence of the double bond in the middle of the alkyl chain of methyl oleate, the formation of some specific products was observed. These species are dienes and esters with two double bonds produced from the decomposition paths of methyl oleate and some species obtained from the addition of H-atoms, OH and HO{sub 2} radicals to the double bond. Experimental results were compared with former results of the oxidation of a blend of n-decane and methyl palmitate performed under similar conditions. This comparison allowed highlighting the similarities and the differences in the reactivity and in the distribution of the reaction products for the oxidation of large saturated and unsaturated esters. (author)

  3. In situ study of e-beam Al and Hf metal deposition on native oxide InP (100)

    SciTech Connect (OSTI)

    Dong, H.; KC, Santosh; Azcatl, A.; Cabrera, W.; Qin, X.; Brennan, B.; Cho, K.; Wallace, R. M.; Zhernokletov, D.

    2013-11-28

    The interfacial chemistry of thin Al (∼3 nm) and Hf (∼2 nm) metal films deposited by electron beam (e-beam) evaporation on native oxide InP (100) samples at room temperature and after annealing has been studied by in situ angle resolved X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. The In-oxides are completely scavenged forming In-In/In-(Al/Hf) bonding after Al and Hf metal deposition. The P-oxide concentration is significantly decreased, and the P-oxide chemical states have been changed to more P-rich oxides upon metal deposition. Indium diffusion through these metals before and after annealing at 250 °C has also been characterized. First principles calculation shows that In has lower surface formation energy compared with Al and Hf metals, which is consistent with the observed indium diffusion behavior.

  4. Reactivity of biogenic manganese oxide for metal sequestration and photochemistry: Computational solid state physics study

    SciTech Connect (OSTI)

    Kwon, K.D.; Sposito, G.

    2010-02-01

    Many microbes, including both bacteria and fungi, produce manganese (Mn) oxides by oxidizing soluble Mn(II) to form insoluble Mn(IV) oxide minerals, a kinetically much faster process than abiotic oxidation. These biogenic Mn oxides drive the Mn cycle, coupling it with diverse biogeochemical cycles and determining the bioavailability of environmental contaminants, mainly through strong adsorption and redox reactions. This mini review introduces recent findings based on quantum mechanical density functional theory that reveal the detailed mechanisms of toxic metal adsorption at Mn oxide surfaces and the remarkable role of Mn vacancies in the photochemistry of these minerals.

  5. Structural transition in rare earth doped zirconium oxide: A positron annihilation study

    SciTech Connect (OSTI)

    Chakraborty, Keka; Bisoi, Abhijit

    2012-11-15

    Graphical abstract: New microstructural analysis and phase transition of rare earth doped mixed oxide compounds such as: Sm{sub 2?x}Dy{sub x}Zr{sub 2}O{sub 7} (where x = 0.0 ? x ? 2.0) that are potentially useful as solid oxide fuels, ionic conductors, optoelectronic materials and most importantly as radiation resistant host for high level rad-waste disposal, structural transition in the system is reported through positron annihilation spectroscopy as there is an indication in the X-ray diffraction analysis. Highlights: ? Zirconium oxide material doped with rare earth ions. ? The method of positron annihilation spectroscopy suggests a phase transition in the system. ? The crystal structure transformation from pure pyrochlore to defect fluorite type of structure is shown by X-ray diffraction results. -- Abstract: A series of compounds with the general composition Sm{sub 2?x}Dy{sub x}Zr{sub 2}O{sub 7} (where 0 ? x ? 2.0) were synthesized by chemical route and characterized by powder X-ray diffraction (XRD) analysis. The rare earth ion namely Sm{sup +3} in the compound was gradually replaced with another smaller and heavier ion, Dy{sup +3} of the 4f series, there by resulting in orderdisorder structural transition, which has been studied by positron annihilation lifetime and Doppler broadening spectroscopy. This study reveals the subtle electronic micro environmental changes in the pyrochlore lattice (prevalent due to the oxygen vacancy in anti-site defect structure of the compound) toward its transformation to defect fluorite structure as found in Dy{sub 2}Zr{sub 2}O{sub 7}. A comparison of the changes perceived with PAS as compared to XRD analysis is critically assayed.

  6. Fundamental Study of the Oxidation Characteristics and Pollutant Emissions of Model Biodiesel Fuels

    SciTech Connect (OSTI)

    Feng, Q.; Wang, Y. L.; Egolfopoulos, Fokion N.; Tsotsis, T. T.

    2010-07-18

    In this study, the oxidation characteristics of biodiesel fuels are investigated with the goal of contributing toward the fundamental understanding of their combustion characteristics and evaluating the effect of using these alternative fuels on engine performance as well as on the environment. The focus of the study is on pure fatty acid methyl-esters (FAME,) that can serve as surrogate compounds for real biodiesels. The experiments are conducted in the stagnation-flow configuration, which allows for the systematic evaluation of fundamental combustion and emission characteristics. In this paper, the focus is primarily on the pollutant emission characteristics of two C{sub 4} FAMEs, namely, methyl-butanoate and methyl-crotonate, whose behavior is compared with that of n-butane and n-pentane. To provide insight into the mechanisms of pollutant formation for these fuels, the experimental data are compared with computed results using a model with consistent C1-C4 oxidation and NOx formation kinetics.

  7. Studies of the Atomic and Crystalline Characteristics of Ceramic Oxide Nano Powders after Bio field Treatment

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

    Article Open Access Industrial Engineering & Management Trivedi et al., Ind Eng Manage 2015, 4:3 http://dx.doi.org/10.4172/2169-0316.1000161 Volume 4 * Issue 3 * 1000161 Ind Eng Manage ISSN: 2169-0316, IEM an open access journal Keywords: Biofield treatment; Iron oxide; Copper oxide; Zinc oxide; X-ray diffraction; FT-IR Introduction Transition metal oxides (TMOs) exhibit fascinating properties such as piezoelectricity, ferroelectricity, nonlinear optical behaviour, wide band gap and high-TC

  8. In-situ DRIFTS measurements for the mechanistic study of NO oxidation over a commercial Cu-CHA catalyst

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

    Ruggeri, Maria Pia; Nova, Isabella; Tronconi, Enrico; Pihl, Josh A.; Toops, Todd J.; Partridge, Jr., William P.

    2014-11-03

    We report a mechanistic DRIFTS in-situ study of NO2, NO + O2 and NO adsorption on a commercial Cu-CHA catalyst for NH3-SCR of NOx. Both pre-reduced and pre-oxidized catalyst samples were investigated with the aim of clarifying mechanistic aspects of the NO oxidation to NO2 as a preliminary step towards the study of the Standard SCR reaction mechanism at low temperatures. Nitrosonium cations (NO+, N formal oxidation state = +3) were identified as key surface intermediates in the process of NO (+2) oxidation to NO2 (+4) and nitrates (+5). While NO+ and nitrates were formed simultaneously upon catalyst exposure tomore » NO2, nitrates evolved consecutively to NO+ when the catalyst was exposed to NO + O2, suggesting that nitrite-like species, and not NO2, are formed as the primary products of the NO oxidative activation over Cu-CHA. Upon catalyst exposure to NO only, i.e. in the absence of gaseous O2, NO+ and then nitrates were formed on a pre-oxidized sample but not on a pre-reduced one, which demonstrates the red-ox nature of the NO oxidation mechanism. The negative effect of H2O on NO+ and nitrates formation was also clearly established. Assuming Cu dimers as the active sites for NO oxidation to NO2, we propose a mechanism which reconciles all the experimental observations. Specifically, we show that such a mechanism also explains the observed kinetic effects of H2O, O2 and NO2 on the NO oxidation activity of the investigated Cu zeolite catalyst.« less

  9. Cost Study for Manufacturing of Solid Oxide Fuel Cell Power Systems

    SciTech Connect (OSTI)

    Weimar, Mark R.; Chick, Lawrence A.; Gotthold, David W.; Whyatt, Greg A.

    2013-09-30

    Solid oxide fuel cell (SOFC) power systems can be designed to produce electricity from fossil fuels at extremely high net efficiencies, approaching 70%. However, in order to penetrate commercial markets to an extent that significantly impacts world fuel consumption, their cost will need to be competitive with alternative generating systems, such as gas turbines. This report discusses a cost model developed at PNNL to estimate the manufacturing cost of SOFC power systems sized for ground-based distributed generation. The power system design was developed at PNNL in a study on the feasibility of using SOFC power systems on more electric aircraft to replace the main engine-mounted electrical generators [Whyatt and Chick, 2012]. We chose to study that design because the projected efficiency was high (70%) and the generating capacity was suitable for ground-based distributed generation (270 kW).

  10. Applications of pulsed EPR spectroscopy to structural studies of sulfite oxidizing enzymes

    SciTech Connect (OSTI)

    Klein, Eric L.; Astashkin, Andrei V.; Raitsimring, Arnold; Enemark, John H.

    2013-01-01

    Sulfite oxidizing enzymes (SOEs), including sulfite oxidase (SO) and bacterial sulfite dehydrogenase (SDH), catalyze the oxidation of sulfite (SO32?) to sulfate (SO42?). The active sites of SO and SDH are nearly identical, each having a 5-coordinate, pseudo-square-pyramidal Mo with an axial oxo ligand and three equatorial sulfur donor atoms. One sulfur is from a conserved Cys residue and two are from a pyranopterindithiolene (molybdopterin, MPT) cofactor. The identity of the remaining equatorial ligand, which is solvent-exposed, varies during the catalytic cycle. Numerous in vitro studies, particularly those involving electron paramagnetic resonance (EPR) spectroscopy of the Mo(V) states of SOEs, have shown that the identity and orientation of this exchangeable equatorial ligand depends on the buffer pH, the presence and concentration of certain anions in the buffer, as well as specific point mutations in the protein. Until very recently, however, EPR has not been a practical technique for directly probing specific structures in which the solvent-exposed, exchangeable ligand is an O, OH?, H2O, SO32?, or SO42? group, because the primary O and S isotopes (16O and 32S) are magnetically silent (I = 0). This review focuses on the recent advances in the use of isotopic labeling, variable-frequency high resolution pulsed EPR spectroscopy, synthetic model compounds, and DFT calculations to elucidate the roles of various anions, point mutations, and steric factors in the formation, stabilization, and transformation of SOE active site structures.

  11. Lithium-decorated oxidized graphyne for hydrogen storage by first principles study

    SciTech Connect (OSTI)

    Yan, Zeyu; Wang, Lang; Cheng, Julong; Huang, Libei; Zhu, Chao; Chen, Chi; Miao, Ling Jiang, Jianjun

    2014-11-07

    The geometric stability and hydrogen storage capacity of Li decorated oxidized ?-graphyne are studied based on the first-principles calculations. It is found that oxygen atoms trend to bond with acetylenic carbons and form C=O double bonds on both sides of graphyne. The binding energy of single Li atom on oxidized graphyne is 3.29?eV, owning to the strong interaction between Li atom and O atom. Meanwhile, the dispersion of Li is stable even under a relatively high density. One attached Li atom can at least adsorb six hydrogen molecules around. Benefitting from the porous structure of graphyne and the high attached Li density, a maximum hydrogen storage density 12.03?wt. % is achieved with four Li atoms in graphyne cell. The corresponding average binding energy is 0.24?eV/H{sub 2}, which is suitable for reversible storage. These results indicate that Li decorated graphyne can serve as a promising hydrogen storage material.

  12. Sodiation kinetics of metal oxide conversion electrodes: A comparative study with lithiation

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

    He, Kai; Lin, Feng; Zhu, Yizhou; Yu, Xiqian; Li, Jing; Lin, Ruoqian; Nordlund, Dennis; Weng, Tsu Chien; Richards, Ryan M.; Yang, Xiao -Qing; et al

    2015-08-19

    The development of sodium ion batteries (NIBs) can provide an alternative to lithium ion batteries (LIBs) for sustainable, low-cost energy storage. However, due to the larger size and higher m/e ratio of the sodium ion compared to lithium, sodiation reactions of candidate electrodes are expected to differ in significant ways from the corresponding lithium ones. In this work, we investigated the sodiation mechanism of a typical transition metal-oxide, NiO, through a set of correlated techniques, including electrochemical and synchrotron studies, real-time electron microscopy observation, and ab initio molecular dynamics (MD) simulations. We found that a crystalline Na₂O reaction layer thatmore » was formed at the beginning of sodiation plays an important role in blocking the further transport of sodium ions. In addition, sodiation in NiO exhibits a “shrinking-core” mode that results from a layer-by-layer reaction, as identified by ab initio MD simulations. For lithiation, however, the formation of Li anti-site defects significantly distorts the local NiO lattice that facilitates Li insertion, thus enhancing the overall reaction rate. These observations delineate the mechanistic difference between sodiation and lithiation in metal-oxide conversion materials. More importantly, our findings identify the importance of understanding the role of reaction layers on the functioning of electrodes and thus provide critical insights into further optimizing NIB materials through surface engineering.« less

  13. Sodiation kinetics of metal oxide conversion electrodes: A comparative study with lithiation

    SciTech Connect (OSTI)

    He, Kai; Lin, Feng; Zhu, Yizhou; Yu, Xiqian; Li, Jing; Lin, Ruoqian; Nordlund, Dennis; Weng, Tsu Chien; Richards, Ryan M.; Yang, Xiao -Qing; Doeff, Marca M.; Stach, Eric A.; Mo, Yifei; Xin, Huolin L.; Su, Dong

    2015-08-19

    The development of sodium ion batteries (NIBs) can provide an alternative to lithium ion batteries (LIBs) for sustainable, low-cost energy storage. However, due to the larger size and higher m/e ratio of the sodium ion compared to lithium, sodiation reactions of candidate electrodes are expected to differ in significant ways from the corresponding lithium ones. In this work, we investigated the sodiation mechanism of a typical transition metal-oxide, NiO, through a set of correlated techniques, including electrochemical and synchrotron studies, real-time electron microscopy observation, and ab initio molecular dynamics (MD) simulations. We found that a crystalline Na₂O reaction layer that was formed at the beginning of sodiation plays an important role in blocking the further transport of sodium ions. In addition, sodiation in NiO exhibits a “shrinking-core” mode that results from a layer-by-layer reaction, as identified by ab initio MD simulations. For lithiation, however, the formation of Li anti-site defects significantly distorts the local NiO lattice that facilitates Li insertion, thus enhancing the overall reaction rate. These observations delineate the mechanistic difference between sodiation and lithiation in metal-oxide conversion materials. More importantly, our findings identify the importance of understanding the role of reaction layers on the functioning of electrodes and thus provide critical insights into further optimizing NIB materials through surface engineering.

  14. Short-Term Oxidation Studies on Nicrofer- 6025HT in Air at Elevated Temperatures for Advanced Coal Based Power Plants

    SciTech Connect (OSTI)

    Joshi, Vineet V.; Meier, Alan; Darsell, Jens T.; Nachimuthu, Ponnusamy; Bowden, Mark E.; Weil, K. Scott

    2013-04-01

    Several advanced air separation unit (ASU) designs being considered for use in coal gasification rely on the use of solid state mixed ionic and electronic conductors. Nicrofer-6025HT, a nickel-based alloy, has been identified as a potential manifold material to transport the hot gases into the ASUs. In the current study, isothermal oxidation tests were conducted on Nicrofer-6025HT in the temperature range of 700900 C for up to 24 h. The evolution of oxide scale was evaluated using SEM, XRD, and XPS. The composite surface oxide layer that formed consisted of an outer chromia-rich scale and an inner alumina scale. For the longer times at the higher temperatures evaluated, a NiCr2O4 spinel phase was located at the interface between the alumina and chromia. Based on the experimental results a four-step oxidation model was proposed.

  15. Ab initio atomistic thermodynamics study on the oxidation mechanism of binary and ternary alloy surfaces

    SciTech Connect (OSTI)

    Liu, Shi-Yu; Liu, Shiyang; Li, De-Jun; Wang, Sanwu; Guo, Jing; Shen, Yaogen

    2015-02-14

    Utilizing a combination of ab initio density-functional theory and thermodynamics formalism, we have established the microscopic mechanisms for oxidation of the binary and ternary alloy surfaces and provided a clear explanation for the experimental results of the oxidation. We construct three-dimensional surface phase diagrams (SPDs) for oxygen adsorption on three different Nb-X(110) (X = Ti, Al or Si) binary alloy surfaces. On the basis of the obtained SPDs, we conclude a general microscopic mechanism for the thermodynamic oxidation, that is, under O-rich conditions, a uniform single-phase SPD (type I) and a nonuniform double-phase SPD (type II) correspond to the sustained complete selective oxidation and the non-sustained partial selective oxidation by adding the X element, respectively. Furthermore, by revealing the framework of thermodynamics for the oxidation mechanism of ternary alloys through the comparison of the surface energies of two separated binary alloys, we provide an understanding for the selective oxidation behavior of the Nb ternary alloy surfaces. Using these general microscopic mechanisms, one could predict the oxidation behavior of any binary and multi-component alloy surfaces based on thermodynamics considerations.

  16. SUPERCRITICAL WATER PARTIAL OXIDATION PHASE I - PILOT-SCALE TESTING / FEASIBILITY STUDIES FINAL REPORT

    SciTech Connect (OSTI)

    SPRITZER,M; HONG,G

    2005-01-01

    Under Cooperative Agreement No. DE-FC36-00GO10529 for the Department of Energy, General Atomics (GA) is developing Supercritical Water Partial Oxidation (SWPO) as a means of producing hydrogen from low-grade biomass and other waste feeds. The Phase I Pilot-scale Testing/Feasibility Studies have been successfully completed and the results of that effort are described in this report. The Key potential advantages of the SWPO process is the use of partial oxidation in-situ to rapidly heat the gasification medium, resulting in less char formation and improved hydrogen yield. Another major advantage is that the high-pressure, high-density aqueous environment is ideal for reaching and gasifying organics of all types. The high water content of the medium encourages formation of hydrogen and hydrogen-rich products and is especially compatible with high water content feeds such as biomass materials. The high water content of the medium is also effective for gasification of hydrogen-poor materials such as coal. A versatile pilot plant for exploring gasification in supercritical water has been established at GA's facilities in San Diego. The Phase I testing of the SWPO process with wood and ethanol mixtures demonstrated gasification efficiencies of about 90%, comparable to those found in prior laboratory-scale SCW gasification work carreid out at the University of Hawaii at Manoa (UHM) as well as other biomass gasification experience with conventional gasifiers. As in the prior work at UHM, a significant amount of the hydrogen found in the gas phase products is derived from the water/steam matrix. The studies at UHM utilized an indirectly heated gasifier with an acitvated carbon catalyst. In contrast, the GA studies utilized a directly heated gasifier without catalyst, plus a surrogate waste fuel. Attainment of comparable gasification efficiencies without catalysis is an important advancement for the GA process, and opens the way for efficient hydrogen production from low

  17. A study of a ceria-zirconia-supported manganese oxide catalyst for combustion of Diesel soot particles

    SciTech Connect (OSTI)

    Sanchez Escribano, V.; Fernandez Lopez, E.; del Hoyo Martinez, C.; Pistarino, C.; Panizza, M.; Resini, C.; Busca, G.

    2008-04-15

    A study has been conducted on the structural and morphological characterization of a Ce-Zr mixed oxide-supported Mn oxide as well as on its catalytic activity in the oxidation of particulate matter arising from Diesel engines. X-ray powder diffraction analysis (XRD) and FT-IR and FT-Raman spectroscopy evidence that the support is a fluorite-like ceria-zirconia solid solution, whereas the supported phase corresponds to the manganese oxide denoted as bixbyite ({alpha}-Mn{sub 2}O{sub 3}). Thermal analyses and FT-IR spectra in air at varying temperatures of soot mechanically mixed with the catalyst evidence that the combustion takes place to a total extent in the range 420-720 K, carboxylic species being detected as intermediate compounds. Moreover, the soot oxidation was studied in a flow reactor and was found to be selective to CO{sub 2}, with CO as by-product in the range 420-620 K. The amount of the generated CO decreases significantly with increasing O{sub 2} concentration in the feed. (author)

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

    SciTech Connect (OSTI)

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

    1993-09-15

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

  19. Hydrothermal synthesis of nanostructured zinc oxide and study of their optical properties

    SciTech Connect (OSTI)

    Moulahi, A.; Sediri, F.; Gharbi, N.

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Nanostructured ZnO were successfully obtained by a hydrothermal route. Black-Right-Pointing-Pointer Inorganic precursor and molar ratio are key factors for morphology and particle size. Black-Right-Pointing-Pointer Optical properties were also studied. -- Abstract: Nanostructured ZnO (nanorods, nanoshuttles) have been synthesized by hydrothermal approach using ZnCl{sub 2} or Zn(NO{sub 3}){sub 2}{center_dot}6H{sub 2}O as zinc sources and cetyltrimethylammonium bromide as structure-directing agent. Techniques X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible absorption, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy have been used to characterize the structure, morphology and composition of the nanostructured zinc oxide. The optical properties of the as-obtained materials were also studied and showing that it is possible to apply the ZnO nanoshuttles and nanorods on the UV filter, photocatalysis, and special optical devices.

  20. HRTEM Study of Oxide Nanoparticles in K3-ODS Ferritic Steel Developed for Radiation Tolerance

    SciTech Connect (OSTI)

    Hsiung, L; Fluss, M; Tumey, S; Kuntz, J; El-Dasher, B; Wall, M; Choi, W; Kimura, A; Willaime, F; Serruys, Y

    2009-11-02

    Crystal and interfacial structures of oxide nanoparticles and radiation damage in 16Cr-4.5Al-0.3Ti-2W-0.37 Y{sub 2}O{sub 3} ODS ferritic steel have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. Oxide nanoparticles with a complex-oxide core and an amorphous shell were frequently observed. The crystal structure of complex-oxide core is identified to be mainly monoclinic Y{sub 4}Al{sub 2}O{sub 9} (YAM) oxide compound. Orientation relationships between the oxide and the matrix are found to be dependent on the particle size. Large particles (> 20 nm) tend to be incoherent and have a spherical shape, whereas small particles (< 10 nm) tend to be coherent or semi-coherent and have a faceted interface. The observations of partially amorphous nanoparticles and multiple crystalline domains formed within a nanoparticle lead us to propose a three-stage mechanism to rationalize the formation of oxide nanoparticles containing core/shell structures in as-fabricated ODS steels. Effects of nanoparticle size and density on cavity formation induced by (Fe{sup 8+} + He{sup +}) dual-beam irradiation are briefly addressed.

  1. Screening study of mixed transition-metal oxides for use as cathodes in thermal batteries

    SciTech Connect (OSTI)

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

    1996-05-01

    Over 100 candidates were examined, including commercial materials and many that were synthesized in house. The mixed oxides were based on Ti, V, Nb, Cr, Mo, W, Mn, Fe, Co, Ni, and Cu doped with other transition metals. A number of individual (single-metal) oxides were included for comparison. The candidates were tested in single cells with Li(Si) anodes and separators based on LiCl-KCl eutectic. Screening was done under constant-current conditions at current densities of 125 me/cm{sup 2} and, to a lesser extent, 50 me/cm{sup 2} at 500 C. Relative performance and limitations of the oxide cathodes are discussed.

  2. In-situ DRIFTS measurements for the mechanistic study of NO oxidation over a commercial Cu-CHA catalyst

    SciTech Connect (OSTI)

    Ruggeri, Maria Pia; Nova, Isabella; Tronconi, Enrico; Pihl, Josh A.; Toops, Todd J.; Partridge, Jr., William P.

    2014-11-03

    We report a mechanistic DRIFTS in-situ study of NO2, NO + O2 and NO adsorption on a commercial Cu-CHA catalyst for NH3-SCR of NOx. Both pre-reduced and pre-oxidized catalyst samples were investigated with the aim of clarifying mechanistic aspects of the NO oxidation to NO2 as a preliminary step towards the study of the Standard SCR reaction mechanism at low temperatures. Nitrosonium cations (NO+, N formal oxidation state = +3) were identified as key surface intermediates in the process of NO (+2) oxidation to NO2 (+4) and nitrates (+5). While NO+ and nitrates were formed simultaneously upon catalyst exposure to NO2, nitrates evolved consecutively to NO+ when the catalyst was exposed to NO + O2, suggesting that nitrite-like species, and not NO2, are formed as the primary products of the NO oxidative activation over Cu-CHA. Upon catalyst exposure to NO only, i.e. in the absence of gaseous O2, NO+ and then nitrates were formed on a pre-oxidized sample but not on a pre-reduced one, which demonstrates the red-ox nature of the NO oxidation mechanism. The negative effect of H2O on NO+ and nitrates formation was also clearly established. Assuming Cu dimers as the active sites for NO oxidation to NO2, we propose a mechanism which reconciles all the experimental observations. Specifically, we show that such a mechanism also explains the observed kinetic effects of H2O, O2 and NO2 on the NO oxidation activity of the investigated Cu zeolite catalyst.

  3. Comprehensive study and design of scaled metal/high-k/Ge gate stacks with ultrathin aluminum oxide interlayers

    SciTech Connect (OSTI)

    Asahara, Ryohei; Hideshima, Iori; Oka, Hiroshi; Minoura, Yuya; Hosoi, Takuji Shimura, Takayoshi; Watanabe, Heiji; Ogawa, Shingo; Yoshigoe, Akitaka; Teraoka, Yuden

    2015-06-08

    Advanced metal/high-k/Ge gate stacks with a sub-nm equivalent oxide thickness (EOT) and improved interface properties were demonstrated by controlling interface reactions using ultrathin aluminum oxide (AlO{sub x}) interlayers. A step-by-step in situ procedure by deposition of AlO{sub x} and hafnium oxide (HfO{sub x}) layers on Ge and subsequent plasma oxidation was conducted to fabricate Pt/HfO{sub 2}/AlO{sub x}/GeO{sub x}/Ge stacked structures. Comprehensive study by means of physical and electrical characterizations revealed distinct impacts of AlO{sub x} interlayers, plasma oxidation, and metal electrodes serving as capping layers on EOT scaling, improved interface quality, and thermal stability of the stacks. Aggressive EOT scaling down to 0.56 nm and very low interface state density of 2.4 × 10{sup 11 }cm{sup −2}eV{sup −1} with a sub-nm EOT and sufficient thermal stability were achieved by systematic process optimization.

  4. Performance of Blackglas{trademark} composites in 4000-hour oxidation study

    SciTech Connect (OSTI)

    Campbell, S.; Gonczy, S.; McNallan, M.; Cox, A.

    1996-12-31

    The effect of long term (4000 hour) oxidation on the mechanical properties of Blackglas{trademark}-Nitrided Nextel{trademark}312 Ceramic Matrix Composites in the temperature range of 500{degrees} - 700{degrees}C was investigated. Flexure specimens of the title composites prepared using three different pyrolysis processes were subjected to oxidation in flowing dry air at 500{degrees}, 600{degrees}C, and 700{degrees}C. Samples were removed at several different time intervals for 3-point flexure analysis. Results indicate that processing conditions had very little effect on the oxidation resistance of this system. At 600{degrees} and 700{degrees}C the mechanical properties degrade continuously to a steady value about half the original flexure strength. At 500{degrees}C, material properties initially improve then begin to slowly degrade. Optical microscopy indicates that oxidation of the matrix begins at the matrix/fiber interface and microcracks and proceeds into the bulk of the matrix.

  5. Laboratory flammability studies of mixtures of hydrogen, nitrous oxide, and air

    SciTech Connect (OSTI)

    Cashdollar, K L; Hertzberg, M; Zlochower, I A; Lucci, C E; Green, G M; Thomas, R A

    1992-06-26

    At the request of the Department of Energy and the Westinghouse Hanford Company, the Bureau of Mines has investigated the flammability of mixtures of hydrogen, nitrous oxide, and air. This work is relevant to the possible hazards of flammable gas generation from nuclear waste tanks at Hanford, WA. The tests were performed in a 120-L spherical chamber under both quiescent and turbulent conditions using both electric spark and pyrotechnic ignition sources. The data reported here for binary mixtures of hydrogen in air generally confirm the data of previous investigators, but they are more comprehensive than those reported previously. The results clarify to a greater extent the complications associated with buoyancy, turbulence, and selective diffusion. The data reported here for ternary mixtures of hydrogen and nitrous oxide in air indicate that small additions of nitrous oxide (relative to the amount of air) have little effect, but that higher concentrations of nitrous oxide (relative to air) significantly increase the explosion hazard.

  6. A rapid compression machine study of the oxidation of propane in the negative temperature coefficient regime

    SciTech Connect (OSTI)

    Gallagher, S.M.; Curran, H.J.; Metcalfe, W.K.; Healy, D.; Simmie, J.M.; Bourque, G.

    2008-04-15

    The oxidation of propane has been studied in the temperature range 680-970 K at compressed gas pressures of 21, 27, and 37 atm and at varying equivalence ratios of 0.5, 1.0, and 2.0. These data are consistent with other experiments presented in the literature for alkane fuels in that, when ignition delay times are plotted as a function of temperature, a characteristic negative coefficient behavior is observed. In addition, these data were simulated using a detailed chemical kinetic model. It was found that qualitatively the model correctly simulated the effect of change in equivalence ratio and pressure, predicting that fuel-rich, high-pressure mixtures ignite fastest, while fuel-lean, low-pressure mixtures ignite slowest. Moreover, reactivity as a function of temperature is well captured, with the model predicting negative temperature coefficient behavior similar to the experiments. Quantitatively the model is faster than experiment for all mixtures at the lowest temperatures (650-750 K) and is also faster than experiment throughout the entire temperature range for fuel-lean mixtures. (author)

  7. STUDY MAGNETIC EXCITATIONS IN DOPED TRANSITION METAL OXIDES USING INELASTIC NEUTRON SCATTERING

    SciTech Connect (OSTI)

    Dai, Pengcheng

    2014-02-18

    Understanding the interplay between magnetism and superconductivity continues to be a hot topic in modern condensed matter physics. The discovery of high-temperature superconductivity in iron-based materials in 2008 provided an unique opportunity to compare and contrast these materials with traditional high-Tc copper oxide superconductors. Neutron scattering plays an important role in determining the dynamical spin properties in these materials. This proposal is a continuation of previous DOE supported proposal. This report summarizes the final progress we have made over from May 2005 till Aug. 2013. Overall, we continue to carry out extensive neutron scattering experiments on Fe-based materials, focusing on understanding their magnetic properties. In addition, we have established a materials laboratory at UT that has allowed us to grow these superconductors. Because neutron scattering typically demands a large amount of samples, by growing these materials in our own laboratory, we can now pursuit neutron scattering experiments over the entire electronic phase diagram, focusing on regions of interests. The material synthesis laboratory at UT was established entirely with the support of DOE funding. This not only allowed us to carry out neutron scattering experiments, but also permit us to provide samples to other US/International collaborators for studying these materials.

  8. New Surface Radiolabeling Schemes of Super Paramagnetic Iron Oxide Nanoparticles (SPIONs) for Biodistribution Studies

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

    Nallathamby, Prakash D.; Mortensen, Ninell P.; Palko, Heather A.; Malfatti, Mike; Smith, Catherine; Sonnett, Jim; Doktycz, Mitchel John; Gu, Baohua; Roeder, Ryan; Wang, Wei; et al

    2015-01-01

    Nanomaterial based drug delivery systems allow for the independent tuning of the surface chemical and physical properties that affect their biodistribution in vivo and the therapeutic payloads that they are intended to deliver. Additionally, the added therapeutic and diagnostic value of their inherent material properties often provides extra functionality. Iron based nanomaterials with their magnetic properties and 10 easily tailorable surface chemistry are of particular interest as model systems. In this study the core radius of the iron oxide nanoparticles (NPs) was 14.08 3.92 nm while the hydrodynamic radius of the NPs, as determined by Dynamic Light Scattering (DLS), wasmore » between 90 110 nm. In this study, different approaches were explored to create radiolabeled NPs that are stable in solution. The NPs were functionalized with polycarboxylate or polyamine surface functional groups. Polycarboxylate 15 functionalized NPs had a zeta potential of -35 mV and polyamine functionalized NPs had a zeta potential of +40 mV. The polycarboxylate functionalized NPs were chosen for in vivo biodistribution studies and hence were radiolabeled with 14C, with a final activity of 0.097 nCi/mg-1 of NPs. In chronic studies, the biodistribution profile is tracked using low level radiolabeled proxies of the nanoparticles of interest. Conventionally, these radiolabeled proxies are chemically similar but not chemically identical to the non-20 radiolabeled NPs of interest. This study is novel as different approaches were explored to create radiolabeled NPs that are stable, possess a hydrodynamic radius of <100 nm and most importantly they exhibit an identical surface chemical functionality as their non-radiolabeled counterparts. Identical chemical functionality of the radiolabeled probes to the non-radiolabeled probes was an important consideration to generate statistically similar biodistribution data sets using multiple imaging and 25 detection techniques. The radiolabeling

  9. Bioenergetic studies of coal sulfur oxidation by extremely thermophilic bacteria. Final report, September 15, 1992--August 31, 1997

    SciTech Connect (OSTI)

    Kelly, R.M.; Han, C.J.

    1997-12-31

    Thermoacidophilic microorganisms have been considered for inorganic sulfur removal from coal because of expected improvements in rates of both biotic and abiotic sulfur oxidation reactions with increasing temperature. In this study, the bioenergetic response of the extremely thermoacidophilic archaeon, Metallosphaera sedula, to environmental changes have been examined in relation to its capacity to catalyze pyrite oxidation in coal. Given an appropriate bioenergetic challenge, the metabolic response was to utilize additional amounts of energy sources (i.e., pyrite) to survive. Of particular interest were the consequences of exposing the organism to various forms of stress (chemical, nutritional, thermal, pH) in the presence of coal pyrite. Several approaches to take advantage of stress response to accelerate pyrite oxidation by this organism were examined, including attempts to promote acquired thermal tolerance to extend its functional range, exposure to chemical uncouplers and decouplers, and manipulation of heterotrophic and chemolithotrophic tendencies to optimize biomass concentration and biocatalytic activity. Promising strategies were investigated in a continuous culture system. This study identified environmental conditions that promote better coupling of biotic and abiotic oxidation reactions to improve biosulfurization rates of thermoacidophilic microorganisms.

  10. Modeling and experimental studies of oxide covered metal surfaces: TiO{sub 2}/Ti a model system. Progress report

    SciTech Connect (OSTI)

    Smyrl, W.H.

    1991-12-31

    Prior work in our laboratories at the Corrosion Research Center has shown that thin, anodic TiO{sub 2} films formed by the Slow Growth Mode (SGM) on polycrystalline titanium and microcrystalline with a texture that varies from one metal grain to another. Furthermore, the underlying metal grains are mapped by the photoelectrochemical response of the oxide. The same characteristics have also been demonstrated in our laboratory for ZnO grown on Zn. The TiO{sub 2}/Ti system has been chosen for study both because of its importance in energy systems, and because it can serve as a model system for other metal-metal oxide couples. The investigations of anodic TiO{sub 2} films on Ti have shown that the properties of thin films are consistent with the rutile form of the oxide. Both experimental data and theoretical calculations show the close resemblance to results on single crystal TiO{sub 2}. Furthermore, the modeling studies reveal that the optical transitions near the bandedge arise from the bulk band structure. The photoelectrochemical properties of anodic TiO{sub 2} films have now been shown to obey the simple Gaertner-Butler model for the semiconductor-electrolyte interface, with a few modifications. The most important deviation has now been shown to be a result of multiple internal reflections in the oxide film.

  11. Modeling and experimental studies of oxide covered metal surfaces: TiO sub 2 /Ti a model system

    SciTech Connect (OSTI)

    Smyrl, W.H.

    1991-01-01

    Prior work in our laboratories at the Corrosion Research Center has shown that thin, anodic TiO{sub 2} films formed by the Slow Growth Mode (SGM) on polycrystalline titanium and microcrystalline with a texture that varies from one metal grain to another. Furthermore, the underlying metal grains are mapped by the photoelectrochemical response of the oxide. The same characteristics have also been demonstrated in our laboratory for ZnO grown on Zn. The TiO{sub 2}/Ti system has been chosen for study both because of its importance in energy systems, and because it can serve as a model system for other metal-metal oxide couples. The investigations of anodic TiO{sub 2} films on Ti have shown that the properties of thin films are consistent with the rutile form of the oxide. Both experimental data and theoretical calculations show the close resemblance to results on single crystal TiO{sub 2}. Furthermore, the modeling studies reveal that the optical transitions near the bandedge arise from the bulk band structure. The photoelectrochemical properties of anodic TiO{sub 2} films have now been shown to obey the simple Gaertner-Butler model for the semiconductor-electrolyte interface, with a few modifications. The most important deviation has now been shown to be a result of multiple internal reflections in the oxide film.

  12. HRTEM Study of Oxide Nanoparticles in 16Cr-4Al-2W-0.3Ti-0.3Y2O3...

    Office of Scientific and Technical Information (OSTI)

    HRTEM Study of Oxide Nanoparticles in 16Cr-4Al-2W-0.3Ti-0.3Y2O3 ODS Steel Citation Details In-Document Search Title: HRTEM Study of Oxide Nanoparticles in 16Cr-4Al-2W-0.3Ti-0.3Y2O3 ...

  13. Application of Gold Electrodes for the Study of Nickel Based Homogeneous Catalysts for Hydrogen Oxidation

    SciTech Connect (OSTI)

    Nepomnyashchii, Alexander B.; Liu, Fei; Roberts, John A.; Parkinson, Bruce A.

    2013-08-12

    Gold and glassy carbon working electrode materials are compared as suitable substrates for the hydrogen oxidation reaction with Ni(PCy2Nt-Bu2)2(BF4)2 used as a catalyst. Voltammetric responses showing electrocatalytic hydrogen oxidation mediated by the homogeneous electrocatalyst Ni(PCy2Nt-Bu2)2(BF4)2 are identical at glassy carbon and gold electrodes, which shows that gold electrode can be used for hydrogen oxidation reaction. This work is supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under FWP 56073.

  14. Methane and methanol oxidation in supercritical water: Chemical kinetics and hydrothermal flame studies

    SciTech Connect (OSTI)

    Steeper, R.R.

    1996-01-01

    Supercritical water oxidation (SCWO) is an emerging technology for the treatment of wastes in the presence of a large concentration of water at conditions above water`s thermodynamic critical point. A high-pressure, optically accessible reaction cell was constructed to investigate the oxidation of methane and methanol in this environment. Experiments were conducted to examine both flame and non-flame oxidation regimes. Optical access enabled the use of normal and shadowgraphy video systems for visualization, and Raman spectroscopy for in situ measurement of species concentrations. Flame experiments were performed by steadily injecting pure oxygen into supercritical mixtures of water and methane or methanol at 270 bar and at temperatures from 390 to 510{degrees}C. The experiments mapped conditions leading to the spontaneous ignition of diffusion flames in supercritical water. Above 470{degrees}C, flames spontaneously ignite in mixtures containing only 6 mole% methane or methanol. This data is relevant to the design and operation of commercial SCWO processes that may be susceptible to inadvertent flame formation. Non-flame oxidation kinetics experiments measured rates of methane oxidation in supercritical water at 270 bar and at temperatures from 390 to 442{degrees}C. The initial methane concentration was nominally 0.15 gmol/L, a level representative of commercial SCWO processes. The observed methane concentration histories were fit to a one-step reaction rate expression indicating a reaction order close to two for methane and zero for oxygen. Experiments were also conducted with varying water concentrations (0 to 8 gmol/L) while temperature and initial reactant concentrations were held constant. The rate of methane oxidation rises steadily with water concentration up to about 5 gmol/L and then abruptly falls off at higher concentrations.

  15. ReaxFF Study of the Oxidation of Softwood Lignin in View of Carbon Fiber Production

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

    Beste, Ariana

    2014-10-06

    We investigate the oxidative, thermal conversion of softwood lignin by performing molecular dynamics simulations based on a reactive force field (ReaxFF). The lignin samples are constructed from coniferyl alcohol units, which are connected through linkages that are randomly selected from a natural distribution of linkages in softwood. The goal of this work is to simulate the oxidative stabilization step during carbon fiber production from lignin precursor. We find that at simulation conditions where stabilization reactions occur, the lignin fragments have already undergone extensive degradation. The 5-5 linkage shows the highest reactivity towards cyclization and dehydrogenation.

  16. X-ray absorption spectroscopy studies of electrochemically deposited thin oxide films.

    SciTech Connect (OSTI)

    Balasubramanian, M.

    1998-06-02

    We have utilized ''in situ'' X-ray Absorption Fine Structure Spectroscopy to investigate the structure and composition of thin oxide films of nickel and iron that have been prepared by electrodeposition on a graphite substrate from aqueous solutions. The films are generally disordered. Structural information has been obtained from the analysis of the data. We also present initial findings on the local structure of heavy metal ions, e.g. Sr and Ce, incorporated into the electrodeposited nickel oxide films. Our results are of importance in a number of technological applications, among them, batteries, fuel cells, electrochromic and ferroelectric materials, corrosion protection, as well as environmental speciation and remediation.

  17. ReaxFF Study of the Oxidation of Softwood Lignin in View of Carbon Fiber Production

    SciTech Connect (OSTI)

    Beste, Ariana

    2014-01-01

    We investigate the oxidative, thermal conversion of softwood lignin by performing molecular dynamics simulations based on a reactive force field (ReaxFF). The lignin samples are constructed from coniferyl alcohol units, which are connected through linkages that are randomly selected from a natural distribution of linkages in softwood. The goal of this work is to simulate the oxidative stabilization step during carbon fiber production from lignin precursor. We find that at simulation conditions where stabilization reactions occur, the lignin fragments have already undergone extensive degradation. The 5-5 linkage shows the highest reactivity towards cyclization and dehydrogenation.

  18. Recent advances in biosynthetic modeling of nitric oxide reductases and insights gained from nuclear resonance vibrational and other spectroscopic studies

    SciTech Connect (OSTI)

    Chakraborty, Saumen; Reed, Julian; Sage, Timothy; Branagan, Nicole C.; Petrik, Igor D.; Miner, Kyle D.; Hu, Michael Y.; Zhao, Jiyong; Alp, E. Ercan; Lu, Yi

    2015-08-14

    This Forum Article focuses on recent advances in structural and spectroscopic studies of biosynthetic models of nitric oxide reductases (NORs). NORs are complex metalloenzymes found in the denitrification pathway of Earth's nitrogen cycle where they catalyze the proton-dependent twoelectron reduction of nitric oxide (NO) to nitrous oxide (N2O). While much progress has been made in biochemical and biophysical studies of native NORs and their variants, a. clear mechanistic understanding of this important metalloenzyme related to its function is still elusive. We report herein UV vis and nuclear resonance vibrational spectroscopy (NRVS) studies of mononitrosylated intermediates of the NOR reaction of a biosynthetic model. The ability to selectively substitute metals at either heme or nonheme metal sites allows the introduction of independent 57Fe probe atoms at either site, as well as allowing the preparation of analogues of stable reaction intermediates by replacing either metal with a redox inactive metal. Together with previous structural and spectroscopic results, we summarize insights gained from studying these biosynthetic models toward understanding structural features responsible for the NOR activity and its mechanism. As a result, the outlook on NOR modeling is also discussed, with an emphasis on the design of models capable of catalytic turnovers designed based on close mimics of the secondary coordination sphere of native NORs.

  19. Recent advances in biosynthetic modeling of nitric oxide reductases and insights gained from nuclear resonance vibrational and other spectroscopic studies

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

    Chakraborty, Saumen; Reed, Julian; Sage, Timothy; Branagan, Nicole C.; Petrik, Igor D.; Miner, Kyle D.; Hu, Michael Y.; Zhao, Jiyong; Alp, E. Ercan; Lu, Yi

    2015-08-14

    This Forum Article focuses on recent advances in structural and spectroscopic studies of biosynthetic models of nitric oxide reductases (NORs). NORs are complex metalloenzymes found in the denitrification pathway of Earth's nitrogen cycle where they catalyze the proton-dependent twoelectron reduction of nitric oxide (NO) to nitrous oxide (N2O). While much progress has been made in biochemical and biophysical studies of native NORs and their variants, a. clear mechanistic understanding of this important metalloenzyme related to its function is still elusive. We report herein UV vis and nuclear resonance vibrational spectroscopy (NRVS) studies of mononitrosylated intermediates of the NOR reaction ofmore » a biosynthetic model. The ability to selectively substitute metals at either heme or nonheme metal sites allows the introduction of independent 57Fe probe atoms at either site, as well as allowing the preparation of analogues of stable reaction intermediates by replacing either metal with a redox inactive metal. Together with previous structural and spectroscopic results, we summarize insights gained from studying these biosynthetic models toward understanding structural features responsible for the NOR activity and its mechanism. As a result, the outlook on NOR modeling is also discussed, with an emphasis on the design of models capable of catalytic turnovers designed based on close mimics of the secondary coordination sphere of native NORs.« less

  20. Study of Interfacial Interactions Using Thing Film Surface Modification: Radiation and Oxidation Effects in Materials

    SciTech Connect (OSTI)

    Sridharan, Kumar; Zhang, Jinsuo

    2014-01-09

    Interfaces play a key role in dictating the long-term stability of materials under the influence of radiation and high temperatures. For example, grain boundaries affect corrosion by way of providing kinetically favorable paths for elemental diffusion, but they can also act as sinks for defects and helium generated during irradiation. Likewise, the retention of high-temperature strength in nanostructured, oxide-dispersion strengthened steels depends strongly on the stoichiometric and physical stability of the (Y, Ti)-oxide particles/matrix interface under radiation and high temperatures. An understanding of these interfacial effects at a fundamental level is important for the development of materials for extreme environments of nuclear reactors. The goal of this project is to develop an understanding stability of interfaces by depositing thin films of materials on substrates followed by ion irradiation of the film-substrate system at elevated temperatures followed by post-irradiation oxidation treatments. Specifically, the research will be performed by depositing thin films of yttrium and titanium (~500 nm) on Fe-12%Cr binary alloy substrate. Y and Ti have been selected as thin-film materials because they form highly stable protective oxides layers. The Fe-12%Cr binary alloy has been selected because it is representative of ferritic steels that are widely used in nuclear systems. The absence of other alloying elements in this binary alloy would allow for a clearer examination of structures and compositions that evolve during high-temperature irradiations and oxidation treatments. The research is divided into four specific tasks: (1) sputter deposition of 500 nm thick films of Y and Ti on Fe-12%Cr alloy substrates, (2) ion irradiation of the film-substrate system with 2MeV protons to a dose of 2 dpa at temperatures of 300°C, 500°C, and 700°C, (3) oxidation of as-deposited and ion-irradiated samples in a controlled oxygen environment at 500°C and 700°C, (4

  1. History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies

    SciTech Connect (OSTI)

    Larry Zirker; Nathan Jerred; Dr. Indrajit Charit; James Cole

    2012-03-01

    Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.

  2. Theoretical study of reactions of HO{sub 2} in low-temperature oxidation of benzene

    SciTech Connect (OSTI)

    Altarawneh, Mohammednoor; Dlugogorski, Bogdan Z.; Kennedy, Eric M.; Mackie, John C.

    2010-07-15

    We have generated a set of thermodynamic and kinetic parameters for the reactions involving HO{sub 2} in the very early stages of benzene oxidation at low temperatures using density functional theory (DFT). In particular, we report the rate constants for the reactions of HO{sub 2} with benzene and phenyl. The calculated reaction rate constant for the abstraction of H-C{sub 6}H{sub 5} by HO{sub 2} is found to be in good agreement with the limited experimental values. HO{sub 2} addition to benzene is found to be more important than direct abstraction. We show that the reactions of HO{sub 2} with the phenyl radical generate the propagating radical OH in a highly exoergic reaction. The results presented herein should be useful in modeling the oxidation of aromatic compounds at low temperatures. (author)

  3. Study of the effect of plasma-striking atmosphere on Fe-oxidation in thermal dc arc-plasma processing

    SciTech Connect (OSTI)

    Banerjee, I.; Khollam, Y. B.; Mahapatra, S. K.; Das, A. K.; Bhoraskar, S. V.

    2010-11-15

    The effect of plasma-striking atmosphere: air and air+Ar-gas on the crystallization of Fe-oxide phases was studied using dc thermal arc-plasma processing route. The powders were characterized by x-ray diffraction, vibrating sample magnetometry, transmission electron microscopy, and Moessbauer spectroscopy techniques. At room temperature and O{sub 2} rich atmosphere, arc-evaporated Fe{sup 2+} ions oxidize into either {gamma}-Fe{sub 2}O{sub 3} or Fe{sub 3}O{sub 4} depending upon the combining ratio of Fe with molecular O{sub 2}. Fe/O ratio could be adjusted using proper flow rate of Ar gas to crystallize the pure {gamma}-Fe{sub 2}O{sub 3}.

  4. Effect of Surface Oxidation on Interfacial Water Structure at a Pyrite (100) Surface as Studied by Molecular Dynamics Simulation

    SciTech Connect (OSTI)

    Jin, Jiaqi; Miller, Jan D.; Dang, Liem X.; Wick, Collin D.

    2015-06-01

    In the first part of this paper, a Scanning Electron Microscopy and contact angle study of a pyrite surface (100) is reported describing the relationship between surface oxidation and the hydrophilic surface state. In addition to these experimental results, the following simulated surface states were examined using Molecular Dynamics Simulation (MDS): fresh unoxidized (100) surface; polysulfide at the (100) surface; elemental sulfur at the (100) surface. Crystal structures for the polysulfide and elemental sulfur at the (100) surface were simulated using Density Functional Theory (DFT) quantum chemical calculations. The well known oxidation mechanism which involves formation of a metal deficient layer was also described with DFT. Our MDS results of the behavior of interfacial water at the fresh and oxidized pyrite (100) surfaces without/with the presence of ferric hydroxide include simulated contact angles, number density distribution for water, water dipole orientation, water residence time, and hydrogen-bonding considerations. The significance of the formation of ferric hydroxide islands in accounting for the corresponding hydrophilic surface state is revealed not only from experimental contact angle measurements but also from simulated contact angle measurements using MDS. The hydrophilic surface state developed at oxidized pyrite surfaces has been described by MDS, on which basis the surface state is explained based on interfacial water structure. The Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences (BES), of the DOE funded work performed by Liem X. Dang. Battelle operates the Pacific Northwest National Laboratory for DOE. The calculations were carried out using computer resources provided by BES.

  5. Magnetic interactions in manganese oxide

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

    Manganese oxide Magnetic interactions in manganese oxide Revealing the mechanism of 'superexchange' May 24, 2016 manganese oxide Manganese oxide Revealing the Nature of Magnetic Interactions in Manganese Oxide For nearly 60 years, scientists have been trying to determine how manganese oxide (MnO) achieves its long-range magnetic order of alternating up and down electron spins. Now, a team of scientists has used their recently developed mathematical approach to study the short-range magnetic

  6. Oxidized crystalline (3 1)-O surface phases of InAs and InSb studied by high-resolution photoelectron spectroscopy

    SciTech Connect (OSTI)

    Tuominen, M. E-mail: pekka.laukkanen@utu.fi; Lng, J.; Dahl, J.; Yasir, M.; Mkel, J.; Punkkinen, M. P. J.; Laukkanen, P. E-mail: pekka.laukkanen@utu.fi; Kokko, K.; Kuzmin, M.; Osiecki, J. R.; Schulte, K.

    2015-01-05

    The pre-oxidized crystalline (31)-O structure of InAs(100) has been recently found to significantly improve insulator/InAs junctions for devices, but the atomic structure and formation of this useful oxide layer are not well understood. We report high-resolution photoelectron spectroscopy analysis of (31)-O on InAs(100) and InSb(100). The findings reveal that the atomic structure of (31)-O consists of In atoms with unexpected negative (between ?0.64 and ?0.47?eV) and only moderate positive (In{sub 2}O type) core-level shifts; highly oxidized group-V sites; and four different oxygen sites. These fingerprint shifts are compared to those of previously studied oxides of III-V to elucidate oxidation processes.

  7. SISGR-Fundamental Experimental and Theoretical Studies on a Novel Family of Oxide Catalyst Supports for Water Electrolysis

    SciTech Connect (OSTI)

    Kumta, Prashant

    2014-10-03

    Identification and development of non-noble metal based electro-catalysts or electro-catalysts with significant reduction of expensive noble metal contents (E.g. IrO2, Pt) with comparable electrochemical performance as the standard noble metal/metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a major breakthrough in the generation of hydrogen by water electrolysis. Accomplishing such a system would not only result reduction of the overall capital costs of PEM based water electrolyzers, but also help attain the targeted hydrogen production cost [< $ 3.0 / gallon gasoline equivalent (gge)] comparable to conventional liquid fuels. In line with these goals, it was demonstrated that fluorine doped IrO2 thin films and nanostructured high surface area powders display remarkably higher electrochemical activity, and comparable durability as pure IrO2 electro-catalyst for the oxygen evolution reaction (OER) in PEM based water electrolysis. Furthermore, corrosion resistant SnO2 and NbO2 support has been doped with F and coupled with IrO2 or RuO2 for use as an OER electro-catalyst. A solid solution of SnO2:F or NbO2:F with only 20 - 30 mol.% IrO2 or RuO2 yielding a rutile structure in the form of thin films and bulk nanoparticles displays similar electrochemical activity and stability as pure IrO2/RuO2. This would lead to more than 70 mol.% reduction in the noble metal oxide content. Novel nanostructured ternary (Ir,Sn,Nb)O2 thin films of different compositions FUNDAMENTAL STUDY OF NANOSTRUCTURED ELECTRO-CATALYSTS WITH REDUCED NOBLE METAL CONTENT FOR PEM BASED WATER ELECTROLYSIS 4 have also been studied. It has been shown that (Ir0.40Sn0.30Nb0.30)O2 shows similar electrochemical activity and enhanced chemical robustness as compared to pure IrO2. F doping of the ternary (Ir,Sn,Nb)O2 catalyst helps in further decreasing the noble metal oxide content of the catalyst. As a result, these reduced noble metal oxide catalyst systems would

  8. Colloidally Synthesized Monodisperse Rh Nanoparticles Supported on SBA-15 for Size- and Pretreatment-Dependent Studies of CO Oxidation

    SciTech Connect (OSTI)

    Grass, Michael E.; Joo, Sang Hoon; Somorjai, Gabor A.

    2009-02-12

    A particle size dependence for CO oxidation over rhodium nanoparticles of 1.9-11.3 nm has been investigated and determined to be modified by the existence of the capping agent poly(vinylpyrrolidone) (PVP). The particles were prepared using a polyol reduction procedure with PVP as the capping agent. The Rh nanoparticles were subsequently supported on SBA-15 during hydrothermal synthesis to produce Rh/SBA-15 supported catalysts for size-dependent catalytic studies. CO oxidation by O{sub 2} at 40 Torr CO and 100 Torr O{sub 2} was investigated over two series of Rh/SBA-15 catalysts: as-synthesized Rh/SBA-15 covering the full range of Rh sizes and the same set of catalysts after high temperature calcination and reduction. The turnover frequency at 443 K increases from 0.4 to 1.7 s{sup -1} as the particle size decreases from 11.3 to 1.9 nm for the as-synthesized catalysts. After calcination and reduction, the turnover frequency is between 0.1 and 0.4 s{sup -1} with no particle size dependence. The apparent activation energy for all catalysts is {approx}30 kcal mol{sup -1} and is independent of particle size and thermal treatment. Infrared spectroscopy of CO on the Rh nanoparticles indicates that the heat treatments used influence the mode of CO adsorption. As a result, the particle size dependence for CO oxidation is altered after calcination and reduction of the catalysts. CO adsorbs at two distinct bridge sites on as-synthesized Rh/SBA-15, attributable to metallic Rh(0) and oxidized Rh(I) bridge sites. After calcination and reduction, however, CO adsorbs only at Rh(0) atop sites. The change in adsorption geometry and oxidation activity may be attributable to the interaction between PVP and the Rh surface. This capping agent affect may open new possibilities for the tailoring of metal catalysts using solution nanoparticle synthesis methods.

  9. A Feasibility Study of Steelmaking by Molten Oxide Electrolysis (TRP9956)

    SciTech Connect (OSTI)

    Donald R. Sadoway; Gerbrand Ceder

    2009-12-31

    Molten oxide electrolysis (MOE) is an extreme form of molten salt electrolysis, a technology that has been used to produce tonnage metals for over 100 years - aluminum, magnesium, lithium, sodium and the rare earth metals specifically. The use of carbon-free anodes is the distinguishing factor in MOE compared to other molten salt electrolysis techniques. MOE is totally carbon-free and produces no CO or CO2 - only O2 gas at the anode. This project is directed at assessing the technical feasibility of MOE at the bench scale while determining optimum values of MOE operating parameters. An inert anode will be identified and its ability to sustain oxygen evalution will be demonstrated.

  10. Fundamental Studies of Irradiation-Induced Defect Formation and Fission Product Dynamics in Oxide Fuels

    SciTech Connect (OSTI)

    James Stubbins

    2012-12-19

    The objective of this research program is to address major nuclear fuels performance issues for the design and use of oxide-type fuels in the current and advanced nuclear reactor applications. Fuel performance is a major issue for extending fuel burn-up which has the added advantage of reducing the used fuel waste stream. It will also be a significant issue with respect to developing advanced fuel cycle processes where it may be possible to incorporate minor actinides in various fuel forms so that they can be 'burned' rather than join the used fuel waste stream. The potential to fission or transmute minor actinides and certain long-lived fission product isotopes would transform the high level waste storage strategy by removing the need to consider fuel storage on the millennium time scale.

  11. Mixture Preparation and Nitric Oxide Formation in a GDI Engine studied by Combined Laser Diagnostics and Numerical Modeling

    SciTech Connect (OSTI)

    Volker Sick; Dennis N. Assanis

    2002-11-27

    Through the combination of advanced imaging laser diagnostics with multi-dimensional computer models, a new understanding of the performance of direct-injection gasoline engines is pursuit. The work focuses on the fuel injection process, the breakup of the liquid into a fine spray and the mixing of the fuel with the in-cylinder gases. Non-intrusive laser diagnostics will be used to measure the spatial distribution of droplets and vaporized fuel with very high temporal resolution. These data along with temperature measurements will be used to validate a new spray breakup model for gasoline direct-injection. Experimental data on near wall fuel distributions will be used for comparison with a model that predicts the spray-wall interaction and the dynamics of the liquid film on the surface. Quantitative measurements of local nitric oxide concentrations inside the combustion chamber will provide a critical test for a numerical simulation of the nitric oxide formation process. This model is based on a modified flamelet approach and will be used to study the effects of exhaust gas recirculation.

  12. A detailed kinetic modeling study of toluene oxidation in a premixed laminar flame

    SciTech Connect (OSTI)

    Tian, Z; Pitz, W J; Fournet, R; Glaude, P; Battin-Leclerc, F

    2009-12-18

    An improved chemical kinetic model for the toluene oxidation based on experimental data obtained in a premixed laminar low-pressure flame with vacuum ultraviolet (VUV) photoionization and molecular beam mass spectrometry (MBMS) techniques has been proposed. The present mechanism consists of 273 species up to chrysene and 1740 reactions. The rate constants of reactions of toluene, decomposition, reaction with oxygen, ipso-additions and metatheses with abstraction of phenylic H-atom are updated; new pathways of C{sub 4} + C{sub 2} species giving benzene and fulvene are added. Based on the experimental observations, combustion intermediates such as fulvenallene, naphtol, methylnaphthalene, acenaphthylene, 2-ethynylnaphthalene, phenanthrene, anthracene, 1-methylphenanthrene, pyrene and chrysene are involved in the present mechanism. The final toluene model leads to an overall satisfactory agreement between the experimentally observed and predicted mole fraction profiles for the major products and most combustion intermediates. The toluene depletion is governed by metathese giving benzyl radicals, ipso-addition forming benzene and metatheses leading to C{sub 6}H{sub 4}CH{sub 3} radicals. A sensitivity analysis indicates that the unimolecular decomposition via the cleavage of a C-H bond has a strong inhibiting effect, while decomposition via C-C bond breaking, ipso-addition of H-atom to toluene, decomposition of benzyl radicals and reactions related to C{sub 6}H{sub 4}CH{sub 3} radicals have promoting effect for the consumption of toluene. Moreover, flow rate analysis is performed to illustrate the formation pathways of mono- and polycyclic aromatics.

  13. Non-OH chemistry in oxidation flow reactors for the study of...

    Office of Scientific and Technical Information (OSTI)

    ... Inc., Cincinnati, OH (United States) Columbia Univ., New York, NY (United States); NASA Goddard Institute for Space Studies, New York, NY (United States) Pennsylvania State ...

  14. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed and Entrained-Flow Reactor

    SciTech Connect (OSTI)

    Buitrago, Paula A; Morrill, Mike; Lighty, JoAnn S; Silcox, Geoffrey D

    2014-08-20

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150oC. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150?C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and intraparticle diffusion. The Freundlich isotherm more accurately

  15. Oxidation Potentials of Functionalized Sulfone Solvents for High-Voltage Li-Ion Batteries: A Computational Study

    SciTech Connect (OSTI)

    Shao, Nan; Sun, Xiao-Guang; Dai, Sheng; Jiang, Deen

    2012-01-01

    New electrolytes with large electrochemical windows are needed to meet the challenge for high-voltage Li-ion batteries. Sulfone as an electrolyte solvent boasts of high oxidation potentials. Here we examine the effect of multiple functionalization on sulfone's oxidation potential. We compute oxidation potentials for a series of sulfone-based molecules functionalized with fluorine, cyano, ester, and carbonate groups by using a quantum chemistry method within a continuum solvation model. We find that multifunctionalization is a key to achieving high oxidation potentials. This can be realized through either a fluorether group on a sulfone molecule or sulfonyl fluoride with a cyano or ester group.

  16. Dissolution of thin iron oxide films used as models for iron passive films studied by in situ X-ray absorption near-edge spectroscopy

    SciTech Connect (OSTI)

    Virtanen, S; Schmuki, P.; Davenport, A.J.; Vitus, C.M.

    1997-01-01

    This paper reports results from X-ray absorption near-edge spectroscopy (XANES) studies during polarization of thin sputter-deposited iron oxide films in acidic solutions. The dissolution rate of iron oxides in acidic solutions was found to be strongly increased by the presence of Fe{sup 2+} in the oxide. During anodic polarization in acidic solutions, it is found that dissolution is accelerated by chloride anions in comparison with sulfates. In HCl solutions of increasing concentration, not only does the pH decrease, but also the increasing chloride concentration accelerates dissolution. On the other hand, the dissolution rate in sulfuric acid does not depend on the sulfate (bisulfate) concentration. During anodic polarization, the dissolution rate is fairly independent of the potential, except at very high anodic potentials, and the XANES spectra reveal no changes in the average oxide valence during anodic polarization. Thus the dissolution that takes place is mostly chemical rather than electrochemical. During cathodic polarization, the dissolution rate is independent of the anion in the electrolyte. The findings are interpreted in terms of the negative surface charge of n-type oxides at potentials lower than the flatband potential, retarding anion adsorption on the surface. Hence it is suggested that the detrimental role of chloride anions on the stability of iron oxide films is due to a surface complexation effect. The findings and their relevance to the stability of natural passive films on iron surfaces are discussed.

  17. Study of Heterogeneouse Processes Related to the Chemistry of Tropospheric Oxidants and Aerosols

    SciTech Connect (OSTI)

    Davidovits, Paul; Worsnop, D R; Jayne, J T; Colb, C E

    2013-02-13

    The objective of the studies was to elucidate the heterogeneous chemistry of tropospheric aerosols. Experiments were designed to measure both specifically needed parameters, and to obtain systematic data required to build a fundamental understanding of the nature of gas-surface physical and chemical interactions

  18. ARM - Oxides of Nitrogen

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

    Oxides of Nitrogen Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans Oxides of Nitrogen Oxides of nitrogen, chlorofluorocarbons (CFCs), and ozone have a lesser effect on the atmosphere than carbon dioxide and methane, but as you will see they are important contributors to the greenhouse

  19. Study on Equilibrium Characteristics of Thorium-Plutonium-Minor Actinides Mixed Oxides Fuel in PWR

    SciTech Connect (OSTI)

    Waris, A.; Permana, S.; Kurniadi, R.; Su'ud, Z.; Sekimoto, H.

    2010-06-22

    A study on characteristics of thorium-plutonium-minor actinides utilization in the pressurized water reactor (PWR) with the equilibrium burnup model has been conducted. For a comprehensive evaluation, several fuel cycles scenario have been included in the present study with the variation of moderator-to-fuel volume ratio (MFR) of PWR core design. The results obviously exhibit that the neutron spectra grow to be harder with decreasing of the MFR. Moreover, the neutron spectra also turn into harder with the rising number of confined heavy nuclides. The required {sup 233}U concentration for criticality of reactor augments with the increasing of MFR for all heavy nuclides confinement and thorium and uranium confinement in PWR.

  20. A study of competitive adsorption of organic molecules onto mineral oxides using DRIFTS

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

    Joan E. Thomas; Kelley, Michael J.

    2009-10-20

    In this study, analysis of DRIFTS spectra was used for a quantitative study of competitive adsorption of myristic and salicylic acids onto kaolinite or γ-alumina. Peaks unique to the ring or the chain were selected and single molecule studies used as calibration. Samples were exposed to hexane solution containing equal molecular quantities of each acid. The surface loading of salicylic acid was not influenced by the presence of myristic acid on either mineral but the maximum loading of myristic acid was decreased (46-50%) by salicylic acid. Displacement of myristic acid from {gamma}-alumina, but not kaolinite, was observed when excess salicylicmore » acid remained in solution. A 25% increase in the maximum loading was observed for kaolinite, but not for{gamma}-alumina. On {gamma}-alumina, after a loading of 1 molecule per nm2, increased exposure resulted in salicylic acid adsorption only, this value is approximately the same for salicylic acid adsorption from aqueous solution or for water washed hexane treated samples. Thus a set of sites for adsorption of either acid is indicated together with other energetically less favorable sites, which can be occupied by salicylic, but not by myristic, acid.« less

  1. In situ studies of surface of NiFe2O4 catalyst during complete oxidation of methane

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

    Zhang, Shiran; Shan, Junjun; Nie, Longhui; Nguyen, Luan; Wu, Zili; Tao, Franklin

    2015-12-21

    Here, NiFe2O4 with an inverse spinel structure exhibits high activity for a complete oxidation of methane at 400 °C–425 °C and a higher temperature. The surface of the catalyst and its adsorbates were well characterized with ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and in situ infrared spectroscopy (IR). In situ studies of the surface of NiFe2O4 using AP-XPS suggest the formation of methoxy-like and formate-like intermediates at a temperature lower than 200 °C, supported by the observed vibrational signatures in in situ IR studies. Evolutions of C1s photoemission features and the nominal atomic ratios of C/(Ni + Fe) of themore » catalyst surface suggest that the formate-like intermediate is transformed to product molecules CO2 and H2O in the temperature range of 250–300 °C. In situ studies suggest the formation of a spectator, – Olattice – CH2 – Olattice –. It strongly bonds to surface through C–O bonds and cannot be activated even at 400 °C.« less

  2. A study of competitive adsorption of organic molecules onto mineral oxides using DRIFTS

    SciTech Connect (OSTI)

    Joan E. Thomas, Michael J. Kelley

    2010-02-01

    Analysis of DRIFTS spectra was used for a quantitative study of competitive adsorption of myristic and salicylic acids onto kaolinite or {gamma}-alumina. Peaks unique to the ring or the chain were selected and single molecule studies used as calibration. Samples were exposed to hexane solution containing equal molecular quantities of each acid. The surface loading of salicylic acid was not influenced by the presence of myristic acid on either mineral but the maximum loading of myristic acid was decreased (46-50%) by salicylic acid. Displacement of myristic acid from {gamma}-alumina, but not kaolinite, was observed when excess salicylic acid remained in solution. A 25% increase in the maximum loading was observed for kaolinite, but not for{gamma}-alumina. On {gamma}-alumina, after a loading of 1 molecule per nm{sup 2}, increased exposure resulted in salicylic acid adsorption only, this value is approximately the same for salicylic acid adsorption from aqueous solution or for water washed hexane treated samples. Thus a set of sites for adsorption of either acid is indicated together with other energetically less favorable sites, which can be occupied by salicylic, but not by myristic, acid.

  3. Micro structural studies of PVA doped with metal oxide nanocomposites films

    SciTech Connect (OSTI)

    Kumar, N. B. Rithin [Dept. of Physics, Srinivas School of Engineering, Mangalore-575025, Karnataka (India); Crasta, Vincent, E-mail: vcrasta@yahoo.com; Viju, F. [Dept. of Physics, St. Joseph Engineering College, Vamanjoor, Mangalore-575028, Karnataka (India); Praveen, B. M. [Dept. of Chemistry, Srinivas School of Engineering, Mangalore-575025, Karnataka (India); Shreeprakash, B. [Dept. of Mechanical Engineering, Srinivas School of Engineering, Mangalore-575025, Karnataka (India)

    2014-04-24

    Nanostructured PVA polymer composites are of rapidly growing interest because of their sized-coupled properties. The present article deals with both ZnO and WO{sub 3} embedded in a polyvinyl alcohol (PVA) matrix using a solvent casting method. These films were characterized using FTIR, XRD, and SEM techniques. The FTIR spectra of the doped PVA shows shift in the bands, which can be understood on the basis of intra/inter molecular hydrogen bonding with the adjacent OH group of PVA. The phase homogeneity and morphology of the polymer composites have been analyzed using scanning electron microscope (SEM). The crystal structure and crystallinity of polymer nanocomposites were studied by X-ray diffraction technique (XRD). Thus due to the interaction of dopant and complex formation, the structural repositioning takes place and crystallinity of the nanocomposites decreases.

  4. Soft X-Ray Spectroscopic Study of Dense Strontium-Doped Lanthanum Manganite Cathodes for Solid Oxide Fuel Cell Applications

    SciTech Connect (OSTI)

    L Piper; A Preston; S Cho; A DeMasi; J Laverock; K Smith; L Miara; J Davis; S Basu; et al.

    2011-12-31

    The evolution of the Mn charge state, chemical composition, and electronic structure of La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSMO) cathodes during the catalytic activation of solid oxide fuel cell (SOFC) has been studies using X-ray spectroscopy of as-processed, exposed, and activated dense thin LSMO films. Comparison of O K-edge and Mn L{sub 3,2}-edge X-ray absorption spectra from the different stages of LSMO cathodes revealed that the largest change after the activation occurred in the Mn charge state with little change in the oxygen environment. Core-level X-ray photoemission spectroscopy and Mn L{sub 3} resonant photoemission spectroscopy studies of exposed and as-processed LSMO determined that the SOFC environment (800 C ambient pressure of O{sub 2}) alone results in La deficiency (severest near the surface with Sr doping >0.55) and a stronger Mn{sup 4+} contribution, leading to the increased insulating character of the cathode prior to activation. Meanwhile, O K-edge X-ray absorption measurements support Sr/La enrichment nearer the surface, along with the formation of mixed Sr{sub x}Mn{sub y}O{sub z} and/or passive MnO{sub x} and SrO species.

  5. A jet-stirred reactor and kinetic modeling study of ethyl propanoate oxidation

    SciTech Connect (OSTI)

    Metcalfe, W.K.; Curran, H.J.; Simmie, J.M.; Togb e, C.; Dagaut, P.

    2009-01-15

    A jet-stirred reactor study of ethyl propanoate, a model biodiesel molecule, has been carried out at 10 atm pressure, using 0.1% fuel at equivalence ratios of 0.3, 0.6, 1.0 and 2.0 and at temperatures in the range 750-1100 K with a constant residence time of 0.7 seconds. Concentration profiles of ethyl propanoate were measured together with those of major intermediates, ethylene, propanoic acid, methane and formaldehyde, and major products, water, carbon dioxide and carbon monoxide. This data was used to further validate a previously published detailed chemical kinetic mechanism, containing 139 species and 790 reversible reactions. It was found that this mechanism required a significant increase in the rate constant of the six-centered unimolecular elimination reaction which produces ethylene and propanoic acid in order to correctly reproduce the measured concentrations of propanoic acid. The revised mechanism was then used to re-simulate shock tube ignition delay data with good agreement observed. Rate of production and sensitivity analyses were carried out under the experimental conditions, highlighting the importance that ethylene chemistry has on the overall reactivity of the system. (author)

  6. Effect of native oxide layers on copper thin-film tensile properties: A reactive molecular dynamics study

    SciTech Connect (OSTI)

    Skarlinski, Michael D.; Quesnel, David J.

    2015-12-21

    Metal-oxide layers are likely to be present on metallic nano-structures due to either environmental exposure during use, or high temperature processing techniques such as annealing. It is well known that nano-structured metals have vastly different mechanical properties from bulk metals; however, difficulties in modeling the transition between metallic and ionic bonding have prevented the computational investigation of the effects of oxide surface layers. Newly developed charge-optimized many body [Liang et al., Mater. Sci. Eng., R 74, 255 (2013)] potentials are used to perform fully reactive molecular dynamics simulations which elucidate the effects that metal-oxide layers have on the mechanical properties of a copper thin-film. Simulated tensile tests are performed on thin-films while using different strain-rates, temperatures, and oxide thicknesses to evaluate changes in yield stress, modulus, and failure mechanisms. Findings indicate that copper-thin film mechanical properties are strongly affected by native oxide layers. The formed oxide layers have an amorphous structure with lower Cu-O bond-densities than bulk CuO, and a mixture of Cu{sub 2}O and CuO charge character. It is found that oxidation will cause modifications to the strain response of the elastic modulii, producing a stiffened modulii at low temperatures (<75 K) and low strain values (<5%), and a softened modulii at higher temperatures. While under strain, structural reorganization within the oxide layers facilitates brittle yielding through nucleation of defects across the oxide/metal interface. The oxide-free copper thin-film yielding mechanism is found to be a tensile-axis reorientation and grain creation. The oxide layers change the observed yielding mechanism, allowing for the inner copper thin-film to sustain an FCC-to-BCC transition during yielding. The mechanical properties are fit to a thermodynamic model based on classical nucleation theory. The fit implies that the oxidation of the

  7. Coloration and oxygen vacancies in wide band gap oxide semiconductors: Absorption at metallic nanoparticles induced by vacancy clustering—A case study on indium oxide

    SciTech Connect (OSTI)

    Albrecht, M. Schewski, R.; Irmscher, K.; Galazka, Z.; Markurt, T.; Naumann, M.; Schulz, T.; Uecker, R.; Fornari, R.; Meuret, S.; Kociak, M.

    2014-02-07

    In this paper, we show by optical and electron microscopy based investigations that vacancies in oxides may cluster and form metallic nanoparticles that induce coloration by extinction of visible light. Optical extinction in this case is caused by generation of localized surface plasmon resonances at metallic particles embedded in the dielectric matrix. Based on Mie's approach, we are able to fit the absorption due to indium nanoparticles in In{sub 2}O{sub 3} to our absorption measurements. The experimentally found particle distribution is in excellent agreement with the one obtained from fitting by Mie theory. Indium particles are formed by precipitation of oxygen vacancies. From basic thermodynamic consideration and assuming theoretically calculated activation energies for vacancy formation and migration, we find that the majority of oxygen vacancies form just below the melting point. Since they are ionized at this temperature they are Coulomb repulsive. Upon cooling, a high supersaturation of oxygen vacancies forms in the crystal that precipitates once the Fermi level crosses the transition energy level from the charged to the neutral charge state. From our considerations we find that the ionization energy of the oxygen vacancy must be higher than 200 meV.

  8. Non-OH chemistry in oxidation flow reactors for the study of atmospheric chemistry systematically examined by modeling

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

    Peng, Zhe; Day, Douglas A.; Ortega, Amber M.; Palm, Brett B.; Hu, Weiwei; Stark, Harald; Li, Rui; Tsigaridis, Kostas; Brune, William H.; Jimenez, Jose L.

    2016-04-06

    Oxidation flow reactors (OFRs) using low-pressure Hg lamp emission at 185 and 254 nm produce OH radicals efficiently and are widely used in atmospheric chemistry and other fields. However, knowledge of detailed OFR chemistry is limited, allowing speculation in the literature about whether some non-OH reactants, including several not relevant for tropospheric chemistry, may play an important role in these OFRs. These non-OH reactants are UV radiation, O(1D), O(3P), and O3. In this study, we investigate the relative importance of other reactants to OH for the fate of reactant species in OFR under a wide range of conditions via box modeling.more » The relative importance of non-OH species is less sensitive to UV light intensity than to water vapor mixing ratio (H2O) and external OH reactivity (OHRext), as both non-OH reactants and OH scale roughly proportionally to UV intensity. We show that for field studies in forested regions and also the urban area of Los Angeles, reactants of atmospheric interest are predominantly consumed by OH. We find that O(1D), O(3P), and O3 have relative contributions to volatile organic compound (VOC) consumption that are similar or lower than in the troposphere. The impact of O atoms can be neglected under most conditions in both OFR and troposphere. We define “riskier OFR conditions” as those with either low H2O (< 0.1%) or high OHRext (≥ 100s–1 in OFR185 and > 200s–1 in OFR254). We strongly suggest avoiding such conditions as the importance of non-OH reactants can be substantial for the most sensitive species, although OH may still dominate under some riskier conditions, depending on the species present. Photolysis at non-tropospheric wavelengths (185 and 254 nm) may play a significant (> 20%) role in the degradation of some aromatics, as well as some oxidation intermediates, under riskier reactor conditions, if the quantum yields are high. Under riskier conditions, some biogenics can have substantial destructions by O3

  9. Non-OH chemistry in oxidation flow reactors for the study of atmospheric chemistry systematically examined by modeling

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

    Peng, Zhe; Day, Douglas A.; Ortega, Amber M.; Palm, Brett B.; Hu, Weiwei; Stark, Harald; Li, Rui; Tsigaridis, Kostas; Brune, William H.; Jimenez, Jose L.

    2016-04-06

    Oxidation flow reactors (OFRs) using low-pressure Hg lamp emission at 185 and 254 nm produce OH radicals efficiently and are widely used in atmospheric chemistry and other fields. However, knowledge of detailed OFR chemistry is limited, allowing speculation in the literature about whether some non-OH reactants, including several not relevant for tropospheric chemistry, may play an important role in these OFRs. These non-OH reactants are UV radiation, O(1D), O(3P), and O3. In this study, we investigate the relative importance of other reactants to OH for the fate of reactant species in OFR under a wide range of conditions via box modeling.more » The relative importance of non-OH species is less sensitive to UV light intensity than to water vapor mixing ratio (H2O) and external OH reactivity (OHRext), as both non-OH reactants and OH scale roughly proportionally to UV intensity. We show that for field studies in forested regions and also the urban area of Los Angeles, reactants of atmospheric interest are predominantly consumed by OH. We find that O(1D), O(3P), and O3 have relative contributions to volatile organic compound (VOC) consumption that are similar or lower than in the troposphere. The impact of O atoms can be neglected under most conditions in both OFR and troposphere. We define “riskier OFR conditions” as those with either low H2O (< 0.1 %) or high OHRext ( ≥  100 s−1 in OFR185 and > 200 s−1 in OFR254). We strongly suggest avoiding such conditions as the importance of non-OH reactants can be substantial for the most sensitive species, although OH may still dominate under some riskier conditions, depending on the species present. Photolysis at non-tropospheric wavelengths (185 and 254 nm) may play a significant (> 20 %) role in the degradation of some aromatics, as well as some oxidation intermediates, under riskier reactor conditions, if the quantum yields are high. Under riskier conditions, some biogenics can have

  10. HRTEM Study of Oxide Nanoparticles in 16Cr-4Al-2W-0.3Ti-0.3Y2O3...

    Office of Scientific and Technical Information (OSTI)

    ...6Cr-4Al-2W-0.3Ti-0.3Y2O3 ODS Steel Citation Details In-Document Search Title: HRTEM Study of Oxide Nanoparticles in 16Cr-4Al-2W-0.3Ti-0.3Y2O3 ODS Steel You are accessing a ...

  11. ZIRCONIUM OXIDE NANOSTRUCTURES PREPARED BY ANODIC OXIDATION

    SciTech Connect (OSTI)

    Dang, Y. Y.; Bhuiyan, M.S.; Paranthaman, M. P.

    2008-01-01

    Zirconium oxide is an advanced ceramic material highly useful for structural and electrical applications because of its high strength, fracture toughness, chemical and thermal stability, and biocompatibility. If highly-ordered porous zirconium oxide membranes can be successfully formed, this will expand its real-world applications, such as further enhancing solid-oxide fuel cell technology. Recent studies have achieved various morphologies of porous zirconium oxide via anodization, but they have yet to create a porous layer where nanoholes are formed in a highly ordered array. In this study, electrochemical methods were used for zirconium oxide synthesis due to its advantages over other coating techniques, and because the thickness and morphology of the ceramic fi lms can be easily tuned by the electrochemical parameters, such as electrolyte solutions and processing conditions, such as pH, voltage, and duration. The effects of additional steps such as pre-annealing and post-annealing were also examined. Results demonstrate the formation of anodic porous zirconium oxide with diverse morphologies, such as sponge-like layers, porous arrays with nanoholes ranging from 40 to 75 nm, and nanotube layers. X-ray powder diffraction analysis indicates a cubic crystallographic structure in the zirconium oxide. It was noted that increased voltage improved the ability of the membrane to stay adhered to the zirconium substrate, whereas lower voltages caused a propensity for the oxide fi lm to fl ake off. Further studies are needed to defi ne the parameters windows that create these morphologies and to investigate other important characteristics such as ionic conductivity.

  12. Studies of Scale Formation and Kinetics of Crofer 22 APU and Haynes 230 in Carbon Oxide-Containing Environment for SOFC Applications

    SciTech Connect (OSTI)

    Ziomek-Moroz, M.; Covino, B.S., Jr.; Holcomb, G.R.; Bullard, S.J.; Penner, L.R.

    2006-01-01

    Significant progress in reducing the operating temperature of SOFCs below 800oC may allow the use of chromia-forming metallic interconnects at a substantial cost savings. Hydrogen is the main fuel for all types of fuel cells except direct methanol fuel cells. Hydrogen can be generated from fossil fuels, including coal, natural gas, diesel, gasoline, other hydrocarbons, and oxygenates (e.g., methanol, ethanol, butanol, etc.). Carbon oxides present in the hydrogen fuel can cause significant performance problems due to carbon formation (coking). Also, literature data indicate that in CO/CO2 gaseous environments, metallic materials that gain their corrosion resistance due to formation of Cr2O3, could form stable chromium carbides. The chromium carbide formation causes depletion of chromium in these alloys. If the carbides oxidize, they form non-protective scales. Considering a potential detrimental effect of carbon oxides on iron- and nickel-base alloy stability, determining corrosion performance of metallic interconnect candidates in carbon oxide-containing environments at SOFC operating temperatures is a must. In this research, the corrosion behavior of Crofer 22 APU and Haynes 230 was studied in a CO-rich atmosphere at 750°C. Chemical composition of the gaseous environment at the outlet was determined using gas chromatography (GC). After 800 h of exposure to the gaseous environment the surfaces of the corroded samples were studied by scanning electron microscopy (SEM) equipped with microanalytical capabilities. X-ray diffraction (XRD) analysis was also used in this study.

  13. Non-OH chemistry in oxidation flow reactors for the study of atmospheric chemistry systematically examined by modeling

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

    Peng, Z.; Day, D. A.; Ortega, A. M.; Palm, B. B.; Hu, W. W.; Stark, H.; Li, R.; Tsigaridis, K.; Brune, W. H.; Jimenez, J. L.

    2015-09-01

    Oxidation flow reactors (OFRs) using low-pressure Hg lamp emission at 185 and 254 nm produce OH radicals efficiently and are widely used in atmospheric chemistry and other fields. However, knowledge of detailed OFR chemistry is limited, allowing speculation in the literature about whether some non-OH reactants, including several not relevant for tropospheric chemistry, may play an important role in these OFRs. These non-OH reactants are UV radiation, O(1D), O(3P), and O3. In this study, we investigate the relative importance of other reactants to OH for the fate of reactant species in OFR under a wide range of conditions via boxmoremodeling. The relative importance of non-OH species is less sensitive to UV light intensity than to relative humidity (RH) and external OH reactivity (OHRext), as both non-OH reactants and OH scale roughly proportional to UV intensity. We show that for field studies in forested regions and also the urban area of Los Angeles, reactants of atmospheric interest are predominantly consumed by OH. We find that O(1D), O(3P), and O3 have relative contributions to VOC consumption that are similar or lower than in the troposphere. The impact of O atoms can be neglected under most conditions in both OFR and troposphere. Under "pathological OFR conditions" of low RH and/or high OHRext, the importance of non-OH reactants is enhanced because OH is suppressed. Some biogenics can have substantial destructions by O3, and photolysis at non-tropospheric wavelengths (185 and 254 nm) may also play a significant role in the degradation of some aromatics under pathological conditions. Working under low O2 with the OFR185 mode allows OH to completely dominate over O3 reactions even for the biogenic species most reactive with O3. Non-tropospheric VOC photolysis may have been a problem in some laboratory and source studies, but can be avoided or lessened in future studies by diluting source emissions and working at lower precursor concentrations in lab studies

  14. A full-dimensional multilayer multiconfiguration time-dependent Hartree study on the ultraviolet absorption spectrum of formaldehyde oxide

    SciTech Connect (OSTI)

    Meng, Qingyong, E-mail: mengqingyong@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian (China); Meyer, Hans-Dieter, E-mail: hans-dieter.meyer@pci.uni-heidelberg.de [Theoretische Chemie, Physikalisch-Chemisches Institut, Ruprecht-Karls Universitt Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)

    2014-09-28

    Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian (MMVCH) model, we perform a full dimensional (9D) quantum dynamical study on the simplest Criegee intermediate, formaldehyde oxide, in five lower-lying singlet electronic states. The ultraviolet (UV) spectrum is then simulated by a Fourier transform of the auto-correlation function. The MMVCH model is built based on extensive MRCI(8e,8o)/aug-cc-pVTZ calculations. To ensure a fast convergence of the final calculations, a large number of ML-MCTDH test calculations is performed to find an appropriate multilayer separations (ML-trees) of the ML-MCTDH nuclear wave functions, and the dynamical calculations are carefully checked to ensure that the calculations are well converged. To compare the computational efficiency, standard MCTDH simulations using the same Hamiltonian are also performed. A comparison of the MCTDH and ML-MCTDH calculations shows that even for the present not-too-large system (9D here) the ML-MCTDH calculations can save a considerable amount of computational resources while producing identical spectra as the MCTDH calculations. Furthermore, the present theoretical B{sup ~} {sup 1}A{sup ?}?X{sup ~} {sup 1}A{sup ?} UV spectral band and the corresponding experimental measurements [J. M. Beames, F. Liu, L. Lu, and M. I. Lester, J. Am. Chem. Soc. 134, 2004520048 (2012); L. Sheps, J. Phys. Chem. Lett. 4, 42014205 (2013); W.-L. Ting, Y.-H. Chen, W. Chao, M. C. Smith, and J. J.-M. Lin, Phys. Chem. Chem. Phys. 16, 1043810443 (2014)] are discussed. To the best of our knowledge, this is the first theoretical UV spectrum simulated for this molecule including nuclear motion beyond an adiabatic harmonic approximation.

  15. Comparative study of the alloying effect on the initial oxidation of Cu-Au(100) and Cu-Pt(100)

    SciTech Connect (OSTI)

    Luo, Langli; Zhou, Guangwen; Kang, Yihong; Yang, Judith C.; Su, Dong; Stach, Eric A.

    2014-03-24

    Using in situ transmission electron microscopy, we show that the oxidation of the Cu-Au(100) results in the formation of Cu{sub 2}O islands that deeply embed into the Cu-Au substrate while the oxidation of the Cu-Pt(100) leads to the formation of Cu{sub 2}O islands that highly protrude above the Cu-Pt substrate. Their difference is attributed to the different mobilities of Pt and Au in the Cu base alloys for which the sluggish mobility of Pt in Cu results in trapped Pt atoms at the oxide/alloy interface while the faster mobility of Au in Cu leads to enhanced rehomogenization of the alloy composition.

  16. Computation Results from a Parametric Study to Determine Bounding Critical Systems of Homogeneously Water-Moderated Mixed Plutonium--Uranium Oxides

    SciTech Connect (OSTI)

    Shimizu, Y.

    2001-01-11

    This report provides computational results of an extensive study to examine the following: (1) infinite media neutron-multiplication factors; (2) material bucklings; (3) bounding infinite media critical concentrations; (4) bounding finite critical dimensions of water-reflected and homogeneously water-moderated one-dimensional systems (i.e., spheres, cylinders of infinite length, and slabs that are infinite in two dimensions) that were comprised of various proportions and densities of plutonium oxides and uranium oxides, each having various isotopic compositions; and (5) sensitivity coefficients of delta k-eff with respect to critical geometry delta dimensions were determined for each of the three geometries that were studied. The study was undertaken to support the development of a standard that is sponsored by the International Standards Organization (ISO) under Technical Committee 85, Nuclear Energy (TC 85)--Subcommittee 5, Nuclear Fuel Technology (SC 5)--Working Group 8, Standardization of Calculations, Procedures and Practices Related to Criticality Safety (WG 8). The designation and title of the ISO TC 85/SC 5/WG 8 standard working draft is WD 14941, ''Nuclear energy--Fissile materials--Nuclear criticality control and safety of plutonium-uranium oxide fuel mixtures outside of reactors.'' Various ISO member participants performed similar computational studies using their indigenous computational codes to provide comparative results for analysis in the development of the standard.

  17. Comparative study of the native oxide on 316L stainless steel by XPS and ToF-SIMS

    SciTech Connect (OSTI)

    Tardio, Sabrina Abel, Marie-Laure; Castle, James E.; Watts, John F.; Carr, Robert H.

    2015-09-15

    The very thin native oxide film on stainless steel, of the order of 2 nm, is known to be readily modified by immersion in aqueous media. In this paper, X-ray photoelectron spectroscopy (XPS) and time of flight secondary ions mass spectrometry are employed to investigate the nature of the air-formed film and modification after water emersion. The film is described in terms of oxide, hydroxide, and water content. The preferential dissolution of iron is shown to occur on immersion. It is shown that a water absorbed layer and a hydroxide layer are present above the oxide-like passive film. The concentrations of water and hydroxide appear to be higher in the case of exposure to water. A secure method for the peak fitting of Fe2p and Cr2p XPS spectra of such films on their metallic substrates is described. The importance of XPS survey spectra is underlined and the feasibility of C{sub 60}{sup +} SIMS depth profiling of a thin oxide layer is shown.

  18. A density functional theory study of the oxidation of methanol to formaldehyde over vanadia supported on silica, titania, and zirconia

    SciTech Connect (OSTI)

    Khaliullin, Rustam Z.; Bell, Alexis T.

    2002-09-05

    Density functional theory was used to investigate the mechanism and kinetics of methanol oxidation to formaldehyde over vanadia supported on silica, titania, and zirconia. The catalytically active site was modeled as an isolated VO{sub 4} unit attached to the support. The calculated geometry and vibrational frequencies of the active site are in good agreement with experimental measurements both for model compounds and oxide-supported vanadia. Methanol adsorption is found to occur preferentially with the rupture of a V-O-M bond (M = Si, Ti, Zr) and with preferential attachment of a methoxy group to V. The vibrational frequencies of the methoxy group are in good agreement with those observed experimentally as are the calculated isobars. The formation of formaldehyde is assumed to occur via the transfer of an H atom of a methoxy group to the O atom of the V=O group. The activation energy for this process is found to be in the range of 199-214 kJ/mol and apparent activation energies for the overall oxidation of methanol to formaldehyde are predicted to lie in the range of 112-123 kJ/mol, which is significantly higher than that found experimentally. Moreover, the predicted turnover frequency (TOF) for methanol oxidation is found to be essentially independent of support composition, whereas experiments show that the TOF is 10{sup 3} greater for titania- and zirconia-supported vanadia than for silica-supported vanadia. Based on these findings, it is proposed that the formation of formaldehyde from methoxy groups may require pairs of adjacent VO{sub 4} groups or V{sub 2}O{sub 7} dimer structures.

  19. An aqueous route to [Ta6O19]8- and solid-state studies of isostructural niobium and tantalum oxide complexes.

    SciTech Connect (OSTI)

    Nyman, May D.; Anderson, Travis Mark; Alam, Todd M.; Rodriguez, Mark Andrew; Joel N. Bixler; Francois Bonhomme

    2007-10-01

    Tantalate materials play a vital role in our high technology society: tantalum capacitors are found in virtually every cell phone. Furthermore, electronic characteristics and the incredibly inert nature of tantalates renders them ideal for applications such as biomedical implants, nuclear waste forms, ferroelectrics, piezoelectrics, photocatalysts and optical coatings. The inert and insoluble nature of tantalates is not fundamentally understood; and furthermore poor solubility renders fabrication of novel or optimized tantalates very difficult. We have developed a soft chemical route to water-soluble tantalum oxide clusters that can serve as both precursors for novel tantalate materials and ideal models for experimental and computational approaches to understanding the unusually inert behavior of tantalates. The water soluble cluster, [Ta6O19]8- is small, highly symmetric, and contains the representative oxygen types of a metal oxide surface, and thus ideally mimics a complex tantalate surface in a simplistic form that can be studied unambiguously. Furthermore; in aqueous solution, these highly charged and super-basic clusters orchestrate surprising acid-base behavior that most likely plays an important role in the inertness of related oxide surfaces. Our unique synthetic approach to the [Ta6O19]8- cluster allowed for unprecedented enrichment with isotopic labels (17O), enabling detailed kinetic and mechanistic studies of the behavior of cluster oxygens, as well as their acid-base behavior. This SAND report is a collection of two publications that resulted from these efforts.

  20. Infrared study on room-temperature atomic layer deposition of HfO{sub 2} using tetrakis(ethylmethylamino)hafnium and remote plasma-excited oxidizing agents

    SciTech Connect (OSTI)

    Kanomata, Kensaku [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan and Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan); Ohba, Hisashi; Pungboon Pansila, P.; Ahmmad, Bashir; Kubota, Shigeru; Hirahara, Kazuhiro; Hirose, Fumihiko, E-mail: fhirose@yz.yamagata-u.ac.jp [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510 (Japan)

    2015-01-01

    Room-temperature atomic layer deposition (ALD) of HfO{sub 2} was examined using tetrakis (ethylmethylamino)hafnium (TEMAH) and remote plasma-excited water and oxygen. A growth rate of 0.26?nm/cycle at room temperature was achieved, and the TEMAH adsorption and its oxidization on HfO{sub 2} were investigated by multiple internal reflection infrared absorption spectroscopy. It was observed that saturated adsorption of TEMAH occurs at exposures of ?1??10{sup 5}?L (1 L?=?1??10{sup ?6} Torr s) at room temperature, and the use of remote plasma-excited water and oxygen vapor is effective in oxidizing the TEMAH molecules on the HfO{sub 2} surface, to produce OH sites. The infrared study suggested that HfOH plays a role as an adsorption site for TEMAH. The reaction mechanism of room temperature HfO{sub 2} ALD is discussed in this paper.

  1. Bio-inspired Design of Electrocatalysts for Oxalate Oxidation: a Combined Experimental and Computational Study of Mn–N–C Catalysts

    SciTech Connect (OSTI)

    Matanovic, Ivana; Babanova, Sofia; Perry, Albert; Serov, Alexey; Artyushkova, Kateryna; Atanassov, Plamen

    2015-05-28

    We report a novel non-platinum group metal (non-PGM) catalyst derived from Mn and amino- antipyrine (MnAAPyr) that shows electrochemical activity towards the oxidation of oxalic acid comparable to Pt with an onset potential for oxalate oxidation measured to be 0.714 * 0.002 V vs. SHE at pH = 4. The material has been synthesized using a templating Sacrificial Support Method with manganese nitrate and 4-aminoantipyrine as precursors. This catalyst is a nano-structured material in which Mn is atomically dispersed on a nitrogendoped graphene matrix. XPS studies reveal high abundance of pyridinic, Mn–Nx, and pyrrolic nitrogen pointing towards the conclusion that pyridinic nitrogen atoms coordinated to manganese constitute the active centers. Thus, the main features of the MnAAPyr catalyst are it exhibits similarity to the active sites of naturally occurring enzymes that are capable of efficient and selective oxidation of oxalic acid. Density functional theory in plane wave formalism with Perdew, Burke and Ernzerhof functional was further used to study the stability and activity of different one-metal active centers that could exist in the catalyst. The results show that the stability of the Mn–Nx sites changes in the following order: MnN4 4 MnN3C 4 MnN2C2 4 MnN3. Based on the overpotentials of 0.64 V and 0.71 V vs. SHE, calculated using the free energy diagrams for the oxalate oxidation mechanism, we could conclude that the MnN3C and MnN2C2 sites are most probable Mn–Nx sites responsible for the reported catalytic activity of the new catalyst.

  2. Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I

    SciTech Connect (OSTI)

    Chinchilla, Diana, E-mail: Diana_Chinchilla@yahoo.com; Kilheeney, Heather, E-mail: raindropszoo@yahoo.com; Vitello, Lidia B., E-mail: lvitello@niu.edu; Erman, James E., E-mail: jerman@niu.edu

    2014-01-03

    Highlights: Cytochrome c peroxidase (CcP) binds acrylonitrile in a pH-independent fashion. The spectrum of the CcP/acrylonitrile complex is that of a 6cls ferric heme. The acrylonitrile/CcP complex has a K{sub D} value of 1.1 0.2 M. CcP compound I oxidizes acrylonitrile with a maximum turnover rate of 0.61 min{sup ?1}. -- Abstract: Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins. In this communication we report on the equilibrium and kinetic properties of acrylonitrile binding to cytochrome c peroxidase (CcP) as well as the oxidation of acrylonitrile by CcP compound I. Acrylonitrile binding to CcP is independent of pH between pH 4 and 8. The association and dissociation rate constants are 0.32 0.16 M{sup ?1} s{sup ?1} and 0.34 0.15 s{sup ?1}, respectively, and the independently measured equilibrium dissociation constant for the complex is 1.1 0.2 M. We have demonstrated for the first time that acrylonitrile can bind to a ferric heme protein. The binding mechanism appears to be a simple, one-step association of the ligand with the heme iron. We have also demonstrated that CcP can catalyze the oxidation of acrylonitrile, most likely to 2-cyanoethylene oxide in a peroxygenase-type reaction, with rates that are similar to rat liver microsomal cytochrome P450-catalyzed oxidation of acrylonitrile in the monooxygenase reaction. CcP compound I oxidizes acrylonitrile with a maximum turnover number of 0.61 min{sup ?1} at pH 6.0.

  3. An In-Situ XAS Study of the Structural Changes in a CuO-CeO2/Al2O3 Catalyst during Total Oxidation of Propane

    SciTech Connect (OSTI)

    Silversmith, Geert; Poelman, Hilde; Poelman, Dirk; Gryse, Roger de; Olea, Maria; Balcaen, Veerle; Heynderickx, Philippe; Marin, Guy B.

    2007-02-02

    A CuOx-CeOx/Al2O3 catalyst was studied with in-situ transmission Cu K XAS for the total oxidation of propane as model reaction for the catalytic elimination of volatile organic compounds. The local Cu structure was determined for the catalyst as such, after pre-oxidation and after reduction with propane. The catalyst as such has a local CuO structure. No structural effect was observed upon heating in He up to 600 deg. C or after pre-oxidation at 150 deg. C. A full reduction of the Cu2+ towards metallic Cu0 occurred, when propane was fed to the catalyst. The change in local Cu structure during propane reduction was followed with a time resolution of 1 min. The {chi}(k) scans appeared as linear combinations of start and end spectra, CuO and Cu structure, respectively. However, careful examination of the XANES edge spectra indicates the presence of a small amount of additional Cu1+ species.

  4. Low and intermediate temperature oxidation of ethanol and ethanol-PRF blends: An experimental and modeling study

    SciTech Connect (OSTI)

    Haas, Francis M.; Chaos, Marcos; Dryer, Frederick L.

    2009-12-15

    In this brief communication, we present new experimental species profile measurements for the low and intermediate temperature oxidation of ethanol under knock-prone conditions. These experiments show that ethanol exhibits no global low temperature reactivity at these conditions, although we note the heterogeneous decomposition of ethanol to ethylene and water. Similar behavior is reported for an E85 blend in n-heptane. Kinetic modeling results are presented to complement these experiments and elucidate the interaction of ethanol and primary reference fuels undergoing cooxidation. (author)

  5. Laboratory Studies of Processing of Carbonaceous Aerosols by Atmospheric Oxidants/Hygroscopicity and CCN Activity of Secondary & Processed Primary Organic Aerosols

    SciTech Connect (OSTI)

    Ziemann, P.J.; Arey, J.; Atkinson, R.; Kreidenweis, S.M.; Petters, M.D.

    2012-06-13

    The atmosphere is composed of a complex mixture of gases and suspended microscopic aerosol particles. The ability of these particles to take up water (hygroscopicity) and to act as nuclei for cloud droplet formation significantly impacts aerosol light scattering and absorption, and cloud formation, thereby influencing air quality, visibility, and climate in important ways. A substantial, yet poorly characterized component of the atmospheric aerosol is organic matter. Its major sources are direct emissions from combustion processes, which are referred to as primary organic aerosol (POA), or in situ processes in which volatile organic compounds (VOCs) are oxidized in the atmosphere to low volatility reaction products that subsequent condense to form particles that are referred to as secondary organic aerosol (SOA). POA and VOCs are emitted to the atmosphere from both anthropogenic and natural (biogenic) sources. The overall goal of this experimental research project was to conduct laboratory studies under simulated atmospheric conditions to investigate the effects of the chemical composition of organic aerosol particles on their hygroscopicity and cloud condensation nucleation (CCN) activity, in order to develop quantitative relationships that could be used to more accurately incorporate aerosol-cloud interactions into regional and global atmospheric models. More specifically, the project aimed to determine the products, mechanisms, and rates of chemical reactions involved in the processing of organic aerosol particles by atmospheric oxidants and to investigate the relationships between the chemical composition of organic particles (as represented by molecule sizes and the specific functional groups that are present) and the hygroscopicity and CCN activity of oxidized POA and SOA formed from the oxidation of the major classes of anthropogenic and biogenic VOCs that are emitted to the atmosphere, as well as model hydrocarbons. The general approach for this project was

  6. Hysteresis-free high rate reactive sputtering of niobium oxide, tantalum oxide, and aluminum oxide

    SciTech Connect (OSTI)

    Srhammar, Erik, E-mail: erik.sarhammar@angstrom.uu.se; Berg, Sren; Nyberg, Tomas [Department of Solid State Electronics, The ngstrm Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden)

    2014-07-01

    This work reports on experimental studies of reactive sputtering from targets consisting of a metal and its oxide. The composition of the targets varied from pure metal to pure oxide of Al, Ta, and Nb. This combines features from both the metal target and oxide target in reactive sputtering. If a certain relation between the metal and oxide parts is chosen, it may be possible to obtain a high deposition rate, due to the metal part, and a hysteresis-free process, due to the oxide part. The aim of this work is to quantify the achievable boost in oxide deposition rate from a hysteresis-free process by using a target consisting of segments of a metal and its oxide. Such an increase has been previously demonstrated for Ti using a homogeneous substoichiometric target. The achievable gain in deposition rate depends on transformation mechanisms from oxide to suboxides due to preferential sputtering of oxygen. Such mechanisms are different for different materials and the achievable gain is therefore material dependent. For the investigated materials, the authors have demonstrated oxide deposition rates that are 1.510 times higher than what is possible from metal targets in compound mode. However, although the principle is demonstrated for oxides of Al, Ta, and Nb, a similar behavior is expected for most oxides.

  7. Oxidation catalyst

    DOE Patents [OSTI]

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  8. Study of hydrogen in coals, polymers, oxides, and muscle water by nuclear magnetic resonance; extension of solid-state high-resolution techniques. [Hydrogen molybdenum bronze

    SciTech Connect (OSTI)

    Ryan, L.M.

    1981-10-01

    Nuclear magnetic resonance (NMR) spectroscopy has been an important analytical and physical research tool for several decades. One area of NMR which has undergone considerable development in recent years is high resolution NMR of solids. In particular, high resolution solid state /sup 13/C NMR spectra exhibiting features similar to those observed in liquids are currently achievable using sophisticated pulse techniques. The work described in this thesis develops analogous methods for high resolution /sup 1/H NMR of rigid solids. Applications include characterization of hydrogen aromaticities in fossil fuels, and studies of hydrogen in oxides and bound water in muscle.

  9. Surface studies on aluminized and thermally oxidized superalloy 690 substrates interacted with simulated nuclear waste and sodium borosilicate melt

    SciTech Connect (OSTI)

    Yusufali, C. Sengupta, P.; Dutta, R. S.; Dey, G. K.; Kshirsagar, R. J.; Mishra, R. K.; Kaushik, C. P.

    2014-04-24

    Aluminized and thermally oxidized Ni-Cr-Fe based superalloy 690 substrates with Al{sub 2}O{sub 3} layer on top have been exposed in nitrate based environment (simulated high level nuclear liquid waste) at 373 K for 216 hours and sodium borosilicate melt at 1248 K for 192 hours. The surfaces of exposed samples have been characterized by using Electron probe micro-analyzer (EPMA). Elemental X-ray mapping on coated specimen that exposed in simulated nuclear waste solution revealed that the surface is enriched with Ni, Cr and Al. X-ray mapping on surface of the specimen that interacted with sodium borosilicate melt indicated that the surface is composed of Al, Fe, Ni and Cr.

  10. Experimental study on vertical scaling of InAs-on-insulator metal-oxide-semiconductor field-effect transistors

    SciTech Connect (OSTI)

    Kim, SangHyeon E-mail: sh-kim@kist.re.kr; Yokoyama, Masafumi; Nakane, Ryosho; Takenaka, Mitsuru; Takagi, Shinichi; Ichikawa, Osamu; Osada, Takenori; Hata, Masahiko

    2014-06-30

    We have investigated effects of the vertical scaling on electrical properties in extremely thin-body InAs-on-insulator (-OI) metal-oxide-semiconductor field-effect transistors (MOSFETs). It is found that the body thickness (T{sub body}) scaling provides better short channel effect (SCE) control, whereas the T{sub body} scaling also causes the reduction of the mobility limited by channel thickness fluctuation (δT{sub body}) scattering (μ{sub fluctuation}). Also, in order to achieve better SCEs control, the thickness of InAs channel layer (T{sub channel}) scaling is more favorable than the thickness of MOS interface buffer layer (T{sub buffer}) scaling from a viewpoint of a balance between SCEs control and μ{sub fluctuation} reduction. These results indicate necessity of quantum well channel structure in InAs-OI MOSFETs and these should be considered in future transistor design.

  11. Exposure to Pb, Cd, and As mixtures potentiates the production of oxidative stress precursors: 30-day, 90-day, and 180-day drinking water studies in rats

    SciTech Connect (OSTI)

    Whittaker, Margaret H.; Wang, Gensheng; Chen Xueqing; Lipsky, Michael; Smith, Donald; Gwiazda, Roberto; Fowler, Bruce A.

    2011-07-15

    Exposure to chemical mixtures is a common and important determinant of toxicity and is of particular concern due to their appearance in sources of drinking water. Despite this, few in vivo mixture studies have been conducted to date to understand the health impact of chemical mixtures compared to single chemicals. Interactive effects of lead (Pb), cadmium (Cd) and arsenic (As) were evaluated in 30-, 90-, and 180-day factorial design drinking water studies in rats designed to test the hypothesis that ingestion of such mixtures at individual component Lowest-Observed-Effect-Levels (LOELs) results in increased levels of the pro-oxidant delta aminolevulinic acid (ALA), iron, and copper. LOEL levels of Pb, Cd, and As mixtures resulted in the increased presence of mediators of oxidative stress such as ALA, copper, and iron. ALA increases were followed by statistically significant increases in kidney copper in the 90- and 180-day studies. Statistical evidence of interaction was identified for six biologically relevant variables: blood delta aminolevulinic acid dehydratase (ALAD), kidney ALAD, urinary ALA, urinary iron, kidney iron, and kidney copper. The current investigations underscore the importance of considering interactive effects that common toxic agents such as Pb, Cd, and As may have upon one another at low-dose levels. The interactions between known toxic trace elements at biologically relevant concentrations shown here demonstrate a clear need to rigorously review methods by which national/international agencies assess health risks of chemicals, since exposures may commonly occur as complex mixtures.

  12. An experimental study on the uptake factor of tungsten oxide particles resulting from an accidentally dropped storage container

    SciTech Connect (OSTI)

    Gao, Zhi; Zhang, J. S.; Byington, Jerry G.A.

    2013-05-16

    A test procedure was developed and verified to measure the airborne concentrations of particles of different sizes (0.5–20 μm) within the vicinity of a dropped container when a significant portion of the tungsten oxide powder (simulating uranium oxide) is ejected from the container. Tests were carried out in a full-scale stainless steel environmental chamber with an interior volume of 24.1 m3. Thirty-two drop tests were performed, covering variations in dropping height, room air movement, landing scenario, and lid condition. Assuming a breathing rate of 1.2 m3/hr, the uptake factor during the first 10 min was calculated to be between 1.13 × 10–9 and 1.03 × 10–7 in reference to the amount loaded; or between 6.44 × 10–8 and 3.55 × 10–4 in reference to the amount spilled. Results provide previously unavailable data for estimating the exposure and associated risk to building occupants in the case of an accidental dropping of heavy powder containers. The test data show that for spills larger than 0.004 g, the power-law correlation between the spill uptake factor and the spilled mass (i.e., SUF = 2.5 × 10–5 × Spill_Mass–0.667) established from the test data is smaller and a more accurate estimate than the constant value of 10–3 assumed in the Department of Energy Nuclear Material Packaging Manual. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplementary resource: an online supplementary table of all cumulative uptake amounts at 10 min for all test data.

  13. A Theoretical Study of Methanol Oxidation Catalyzed by Isolated Vanadia Clusters Supported on the (101) Surface of Anatase

    SciTech Connect (OSTI)

    Shapovalov, Vladimir; Fievez, Tim; Bell, Alexis T.

    2012-08-13

    A theoretical model has been developed for describing isolated vanadate species dispersed on the (101) surface of anatase that takes into account the equilibration of the supported species with gas-phase oxygen. The lowest energy of the combined solid and gas phases identifies the VOx species with the optimal structure and composition. This model of VOx species supported on the surface of anatase is then used to analyze the reaction path for methanol oxidation to formaldehyde. The chemisorption of methanol is found to proceed preferentially by addition across a V-O-Ti bond to form V-OCH3 and Ti-OH species. The rate-limiting step for the formation of formaldehyde takes place via the transfer of a hydrogen atom from V-OCH3 bound to an oxygen atom bridging two Ti atoms, i.e., a Ti-O-Ti group located adjacent to the supported vanadate species. This step is found to have the lowest apparent activation energy of all pathways explored for the formation of formaldehyde.

  14. Operando NMR and XRD study of chemically synthesized LiCx oxidation in a dry room environment

    SciTech Connect (OSTI)

    Sacci, Robert L.; Gill, Lance W.; Hagaman, Edward W.; Dudney, Nancy J.

    2015-04-07

    We test the stability of pre-lithiated graphite anodes for Li-ion batteries in a dry room battery processing room. The reaction between LiCx and laboratory air was followed using operando NMR and x-ray diffraction as these methods are sensitive to change in Li stoichiometry in graphite. There is minimal reactivity between LiC6 and N2, CO2 or O2; however, LiC6 reacts with moisture to form lithium (hydr)oxide. The reaction rate follows zero-order kinetics with respects to intercalated lithium suggesting that lithium transport through the graphite is fast. The reaction mechanism occurs by sequential formation of higher stages LiC12, then LiC18, and then LiC24 as the hydrolysis proceeds to the formation of LixOHy and graphite end products. Slowing down the formation rate of the LixOHy passivation layer stabilizes of the higher stages.

  15. Operando NMR and XRD study of chemically synthesized LiCx oxidation in a dry room environment

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

    Sacci, Robert L.; Gill, Lance W.; Hagaman, Edward W.; Dudney, Nancy J.

    2015-04-07

    We test the stability of pre-lithiated graphite anodes for Li-ion batteries in a dry room battery processing room. The reaction between LiCx and laboratory air was followed using operando NMR and x-ray diffraction as these methods are sensitive to change in Li stoichiometry in graphite. There is minimal reactivity between LiC6 and N2, CO2 or O2; however, LiC6 reacts with moisture to form lithium (hydr)oxide. The reaction rate follows zero-order kinetics with respects to intercalated lithium suggesting that lithium transport through the graphite is fast. The reaction mechanism occurs by sequential formation of higher stages LiC12, then LiC18, and thenmore » LiC24 as the hydrolysis proceeds to the formation of LixOHy and graphite end products. Slowing down the formation rate of the LixOHy passivation layer stabilizes of the higher stages.« less

  16. Operando NMR and XRD study of chemically synthesized LiCx oxidation in a dry room environment

    SciTech Connect (OSTI)

    Sacci, Robert L.; Gill, Lance W.; Hagaman, Edward W.; Dudney, Nancy J.

    2015-08-01

    We test the stability of pre-lithiated graphite anodes for Li-ion batteries in a dry room battery processing room. The reaction between LiCx and laboratory air was followed using operando NMR and x-ray diffraction as these methods are sensitive to change in Li stoichiometry in graphite. There is minimal reactivity between LiC6 and N2, CO2 or O2; however, LiC6 reacts with moisture to form lithium (hydr)oxide. The reaction rate follows zero-order kinetics with respects to intercalated lithium suggesting that lithium transport through the graphite is fast. The reaction mechanism occurs by sequential formation of higher stages LiC12, then LiC18, and then LiC24 as the hydrolysis proceeds to the formation of LixOHy and graphite end products. Slowing down the formation rate of the LixOHy passivation layer stabilizes of the higher stages.

  17. Attachment_1_SOS_Outline.pdf

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

  18. Direct Internal Reformation and Mass Transport in the Solid Oxide Fuel Cell Anode: A Pore-Scale Lattice Boltzmann Study with Detailed Reaction Kinetics

    SciTech Connect (OSTI)

    Grew, Kyle N.; Joshi, Abhijit S.; Chiu, W. K. S.

    2010-11-30

    The solid oxide fuel cell (SOFC) allows the conversion of chemical energy that is stored in a given fuel, including light hydrocarbons, to electrical power. Hydrocarbon fuels, such as methane, are logistically favourable and provide high energy densities. However, the use of these fuels often results in a decreased efficiency and life. An improved understanding of the reactive flow in the SOFC anode can help address these issues. In this study, the transport and heterogeneous internal reformation of a methane based fuel is addressed. The effect of the SOFC anode's complex structure on transport and reactions is shown to exhibit a complicated interplay between the local molar concentrations and the anode structure. Strong coupling between the phenomenological microstructures and local reformation reaction rates are recognised in this study, suggesting the extension to actual microstructures may provide new insights into the reformation processes.

  19. Studies of Human 2,4-Dienoyl CoA Reductase Shed New Light on Peroxisomal ?-Oxidation of Unsaturated Fatty Acids

    SciTech Connect (OSTI)

    Hua, Tian; Wu, Dong; Ding, Wei; Wang, Jiangyun; Shaw, Neil; Liu, Zhi-Jie

    2012-10-15

    Peroxisomes play an essential role in maintaining fatty acid homeostasis. Although mitochondria are also known to participate in the catabolism of fatty acids via ?-oxidation, differences exist between the peroxisomal and mitochondrial ?-oxidation. Only peroxisomes, but not mitochondrion, can shorten very long chain fatty acids. Here, we describe the crystal structure of a ternary complex of peroxisomal 2,4-dienoyl CoA reductases (pDCR) with hexadienoyl CoA and NADP, as a prototype for comparison with the mitochondrial 2,4-dienoyl CoA reductase (mDCR) to shed light on the differences between the enzymes from the two organelles at the molecular level. Unexpectedly, the structure of pDCR refined to 1.84 resolution reveals the absence of the tyrosine-serine pair seen in the active site of mDCR, which together with a lysine and an asparagine have been deemed a hallmark of the SDR family of enzymes. Instead, aspartate hydrogen-bonded to the C? hydroxyl via a water molecule seems to perturb the water molecule for protonation of the substrate. Our studies provide the first structural evidence for participation of water in the DCR-catalyzed reactions. Biochemical studies and structural analysis suggest that pDCRs can catalyze the shortening of six-carbon-long substrates in vitro. However, the Km values of pDCR for short chain acyl CoAs are at least 6-fold higher than those for substrates with 10 or more aliphatic carbons. Unlike mDCR, hinge movements permit pDCR to process very long chain polyunsaturated fatty acids.

  20. Time-Resolved XAFS Spectroscopic Studies of B-H and N-H Oxidative Addition to Transition Metal Catalysts Relevant to Hydrogen Storage

    SciTech Connect (OSTI)

    Bitterwolf, Thomas E.

    2014-12-09

    Successful catalytic dehydrogenation of aminoborane, H3NBH3, prompted questions as to the potential role of N-H oxidative addition in the mechanisms of these processes. N-H oxidative addition reactions are rare, and in all cases appear to involve initial dative bonding to the metal by the amine lone pairs followed by transfer of a proton to the basic metal. Aminoborane and its trimethylborane derivative block this mechanism and, in principle, should permit authentic N-H oxidative attrition to occur. Extensive experimental work failed to confirm this hypothesis. In all cases either B-H complexation or oxidative addition of solvent C-H bonds dominate the chemistry.

  1. Growth control of the oxidation state in vanadium oxide thin...

    Office of Scientific and Technical Information (OSTI)

    Growth control of the oxidation state in vanadium oxide thin films Prev Next Title: Growth control of the oxidation state in vanadium oxide thin films Authors: Lee, Shinbuhm ...

  2. Identifying surface structural changes in layered Li-excess nickel manganese oxides in high voltage lithium ion batteries: A joint experimental and theoretical study

    SciTech Connect (OSTI)

    Xu, Bo; Fell, Christopher R.; Chi, Miaofang; Meng, Ying Shirley

    2011-09-06

    High voltage cathode materials Li-excess layered oxide compounds Li[Ni{sub x}Li{sub 1/3-2x/3}Mn{sub 2/3-x/3}]O{sub 2} (0 < x < 1/2) are investigated in a joint study combining both computational and experimental methods. The bulk and surface structures of pristine and cycled samples of Li[Ni{sub 1/5}Li{sub 1/5}Mn{sub 3/5}]O{sub 2} are characterized by synchrotron X-Ray diffraction together with aberration corrected Scanning Transmission Electron Microscopy (a-S/TEM). Electron Energy Loss Spectroscopy (EELS) is carried out to investigate the surface changes of the samples before/after electrochemical cycling. Combining first principles computational investigation with our experimental observations, a detailed lithium de-intercalation mechanism is proposed for this family of Li-excess layered oxides. The most striking characteristics in these high voltage high energy density cathode materials are (1) formation of tetrahedral lithium ions at voltage less than 4.45 V and (2) the transition metal (TM) ions migration leading to phase transformation on the surface of the materials. We show clear evidence of a new spinel-like solid phase formed on the surface of the electrode materials after high-voltage cycling. It is proposed that such surface phase transformation is one of the factors contributing to the first cycle irreversible capacity and the main reason for the intrinsic poor rate capability of these materials.

  3. Effects of Oxidation on Oxidation-Resistant Graphite

    SciTech Connect (OSTI)

    Windes, William; Smith, Rebecca; Carroll, Mark

    2015-05-01

    The Advanced Reactor Technology (ART) Graphite Research and Development Program is investigating doped nuclear graphite grades that exhibit oxidation resistance through the formation of protective oxides on the surface of the graphite material. In the unlikely event of an oxygen ingress accident, graphite components within the VHTR core region are anticipated to oxidize so long as the oxygen continues to enter the hot core region and the core temperatures remain above 400°C. For the most serious air-ingress accident which persists over several hours or days the continued oxidation can result in significant structural damage to the core. Reducing the oxidation rate of the graphite core material during any air-ingress accident would mitigate the structural effects and keep the core intact. Previous air oxidation testing of nuclear-grade graphite doped with varying levels of boron-carbide (B4C) at a nominal 739°C was conducted for a limited number of doped specimens demonstrating a dramatic reduction in oxidation rate for the boronated graphite grade. This report summarizes the conclusions from this small scoping study by determining the effects of oxidation on the mechanical strength resulting from oxidation of boronated and unboronated graphite to a 10% mass loss level. While the B4C additive did reduce mechanical strength loss during oxidation, adding B4C dopants to a level of 3.5% or more reduced the as-fabricated compressive strength nearly 50%. This effectively minimized any benefits realized from the protective film formed on the boronated grades. Future work to infuse different graphite grades with silicon- and boron-doped material as a post-machining conditioning step for nuclear components is discussed as a potential solution for these challenges in this report.

  4. Studies of Heterogeneously Catalyzed Liquid-Phase Alcohol Oxidation on Platinum bySum-frequency Generation Vibrational Spectroscopy and Reaction Rate Measurements

    SciTech Connect (OSTI)

    Thompson, Christopher

    2014-05-15

    Compared to many branches of chemistry, the molecular level study of catalytically active surfaces is young. Only with the invention of ultrahigh vacuum technology in the past half century has it been possible to carry out experiments that yield useful molecular information about the reactive occurrences at a surface. The reason is two-fold: low pressure is necessary to keep a surface clean for an amount of time long enough to perform an experiment, and most atomic scale techniques that are surface speci c (x-ray photoelectron spectroscopy, electron energy loss spectroscopy, Auger electron spectroscopy, etc.) cannot be used at ambient pressures, because electrons, which act as chemical probes in these techniques, are easily scattered by molecules. Sum-frequency generation (SFG) vibrational spectroscopy is one technique that can provide molecular level information from the surface without the necessity for high vacuum. Since the advent of SFG as a surface spectroscopic tool it has proved its worth in the studies of surface catalyzed reactions in the gas phase, with numerous reactions in the gas phase having been investigated on a multitude of surfaces. However, in situ SFG characterization of catalysis at the solid-liquid interface has yet to be thoroughly pursued despite the broad interest in the use of heterogeneous catalysts in the liquid phase as replacements for homogeneous counterparts. This work describes an attempt to move in that direction, applying SFG to study the solid-liquid interface under conditions of catalytic alcohol oxidation on platinum.

  5. In situ synchrotron radiation photoelectron spectroscopy study of the oxidation of the Ge(100)-2 1 surface by supersonic molecular oxygen beams

    SciTech Connect (OSTI)

    Yoshigoe, Akitaka; Teraoka, Yuden; Okada, Ryuta; Yamada, Yoichi; Sasaki, Masahiro

    2014-11-07

    In situ synchrotron radiation photoelectron spectroscopy was performed during the oxidation of the Ge(100)-2 1 surface induced by a molecular oxygen beam with various incident energies up to 2.2 eV from the initial to saturation coverage of surface oxides. The saturation coverage of oxygen on the clean Ge(100) surface was much lower than one monolayer and the oxidation state of Ge was +2 at most. This indicates that the Ge(100) surface is so inert toward oxidation that complete oxidation cannot be achieved with only pure oxygen (O{sub 2}) gas, which is in strong contrast to Si surfaces. Two types of dissociative adsorption, trapping-mediated and direct dissociation, were confirmed by oxygen uptake measurements depending on the incident energy of O{sub 2}. The direct adsorption process can be activated by increasing the translational energy, resulting in an increased population of Ge{sup 2+} and a higher final oxygen coverage. We demonstrated that hyperthermal O{sub 2} beams remarkably promote the room-temperature oxidation with novel atomic configurations of oxides at the Ge(100) surface. Our findings will contribute to the fundamental understanding of oxygen adsorption processes at 300 K from the initial stages to saturated oxidation.

  6. Study of Geometric Stability and Structural Integrity of Self-Healing Glass Seal System Used in Solid Oxide Fuel Cells

    SciTech Connect (OSTI)

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.

    2011-02-15

    A self-healing glass seal has the potential of restoring its mechanical properties upon being reheated to SOFC stack operating temperature, even when it has experienced some cooling induced damage/cracking at room temperature. Such a self-healing feature is desirable for achieving high seal reliability during thermal cycling. On the other hand, self-healing glass is also characterized by its low mechanical stiffness and high creep rate at the typical operating temperature of SOFCs. Therefore, geometry stability and structural integrity of the glass seal system becomes critical to its successful application in SOFCs. In this paper, the geometry stability of the self-healing glass and the influence of various interfacial conditions of ceramic stoppers with the PEN, IC, and glass seal on the structural integrity of the glass seal during the operating and cooling down processes are studied using finite element analyses. For this purpose, the test cell used in the leakage tests for compliant glass seals conducted at PNNL is taken as the initial modeling geometry. The effect of the ceramic stopper on the geometry stability of the self-healing glass sealants is studied first. Two interfacial conditions of the ceramic stopper and glass seals, i.e., bonded (strong) or un-bonded (weak), are considered. Then the influences of interfacial strengths at various interfaces, i.e., stopper/glass, stopper/PEN, as well as stopper/IC plate, on the geometry stability and reliability of glass during the operating and cooling processes are examined.

  7. Structural Study And Optical Properties Of TiO{sub 2} Thin Films Elaborated By Thermal Oxidation Of RF Magnetron Sputtered Ti Films

    SciTech Connect (OSTI)

    Guitoume, D.; Achour, S.; Guittoum, A.; Abaidia, S. E. H.

    2008-09-23

    We report on the effect of thickness on the structural and optical properties of TiO{sub 2} thin films obtained by direct exposure of Ti metal film to thermal oxidation. Ti thin films with thicknesses ranging from 87 nm to 484 nm were deposited onto glass substrate by RF magnetron sputtering. Thereafter, the as-deposited Ti films were annealed in air at temperature equal to 520 deg. C. The structural evolution and optical properties of obtained TiO{sub 2} films were studied by means of Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and UV-Visible spectroscopy. The films thicknesses were extracted from RBS spectra. From X-ray diffraction spectra, we can see that all the films present three TiO{sub 2} phases (anatase, rutile and Brookite). The anatase and rutile phases exhibit a strong preferred orientation along (004) and (210) planes respectively. The grain sizes, D (nm), did not change much with increasing thickness. The average value of (nm) was equal to 29 nm for anatase and 26 nm for rutile. The micrographs taken from SEM experiments indicate that the films present a dense micro structure with very small grains. Transmittance spectra show that all the films present a good transparency in the visible region. The dependence of transmittance, optical band gap and refractive index on the thickness of the films was also studied.

  8. Transuranic decontamination of nitric acid solutions by the TRUEX solvent extraction process: preliminary development studies. [Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide

    SciTech Connect (OSTI)

    Vandegrift, G.F.; Leonard, R.A.; Steindler, M.J.; Horwitz, E.P.; Basile, L.J.; Diamond, H.; Kalina, D.G.; Kaplan, L.

    1984-07-01

    This report summarizes the work that has been performed to date at Argonne National Laboratory on the development of the TRUEX process, a solvent extraction process employing a bifunctional organophosphorous reagent in a PUREX process solvent (tributyl phosphate-normal paraffinic hydrocarbons). The purpose of this extraction process is to separate and concentrate transuranic (TRU) elements from nuclear waste. Assessments were made of the use of two TRUEX solvents: one incorporating the well-studied dihexyl-N,N-diethylcarbamoylmethylphosphonate (DHDECMP) and a second incorporating an extractant with superior properties for a 1M HNO/sub 3/ acid feed, octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (O/sub phi/D(IB)CMPO). In this report, conceptual flowsheets for the removal of soluble TRUs from high-level nuclear wastes using these two TRUEX proces solvents are presented, and flowsheet features are discussed in detail. The conceptual flowsheet for TRU-element removal from a PUREX waste by the O/sub phi/D(IB)CMPO-TRUEX process solvent was tested in a bench-scale countercurrent experiment, and results of that experiment are presented and discussed. The conclusion of this study is that the TRUEX process is able to separate TRUs from high-level wastes so that the major portion of the solid waste (approx. 99%) can be classified as non-TRU. Areas where more experimentation is needed are listed at the end of the report. 45 references, 17 figures, 56 tables.

  9. lithium cobalt oxide cathode

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

    lithium cobalt oxide cathode - Sandia Energy Energy Search Icon Sandia Home Locations ... SunShot Grand Challenge: Regional Test Centers lithium cobalt oxide cathode Home...

  10. Effects of fungal degradation on the CuO oxidation products of lignin: A controlled laboratory study

    SciTech Connect (OSTI)

    Hedges, J.I.; Weliky, K.; Devol, A.H. ); Blanchette, R.A. )

    1988-11-01

    Duplicate samples of birch wood were degraded for 0, 4, 8 and 12 weeks by the white-rot fungus, Phlebia tremellosus, and for 12 weeks by 6 other white-rot and brown-rot fungi. P. tremellosus caused progressive weight losses and increased the H/C and O/C of the remnant wood by preferentially degrading the lignin component of the middle lamellae. Total yields of syringyl phenols were decreased 1.5 times as fast as total vanillyl phenol yields. Within both phenol families, aldehyde precursors were degraded faster than precursors of the corresponding ketones, which were obtained in constant proportion to the total phenol yield. Although two other white-rot fungi caused similar lignin compositional trends, a fourth white-rot species, Coriolus versicolor, simultaneously eroded all cell wall components and did not concentrate polysaccharides in the remnant wood. The brown-rot fungi also preferentially attacked syringyl structural units, but degraded all phenol precursors at a much slower rate than the white-rotters and did not produce excess vanillic acid. Degradation by P. tremellosus linearly increased the vanillic acid/vanillin ratio, (Ad/Al)v, of the remnant birch wood throughout the 12 week degradation study and exponentially decreased the absolute yields of total vanillyl phenols, total syringyl phenols and the syringyl/vanillyl phenol ratio, S/V. At the highest (Ad/Al)v of 0.50 total yields of syringyl and vanillyl phenols were decreased by 65% and 80%, respectively, with a resulting reduction of 40% in the original S/V. Many of the diagenetically related compositional trends that have been previously reported for lignins in natural environments can be explained by white-rot fungal degradation.

  11. A study of ZnxZryOz mixed oxides for direct conversion of ethanol to isobutene

    SciTech Connect (OSTI)

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

    2013-07-15

    ZnxZryOz mixed oxides were studied for direct conversion of ethanol to isobutene. Reaction conditions (temperature, residence time, ethanol molar fraction, steam to carbon ratio), catalyst composition, and pretreatment conditions were investigated, aiming at high-yield production of isobutene under industrially relevant conditions. An isobutene yield of 79% was achieved with an ethanol molar fraction of 8.3% at 475 °C on fresh Zn1Zr8O17 catalysts. Further durability and regeneration tests revealed that the catalyst exhibited very slow deactivation via coking formation with isobutene yield maintained above 75% for more than 10 h time-on-stream. More importantly, the catalysts activity in terms of isobutene yield can be readily recovered after in situ calcination in air at 550 °C for 2.5 h. XRD, TPO, IR analysis of adsorbed pyridine (IR-Py), and nitrogen sorption have been used to characterize the surface physical/chemical properties to correlate the structure and performance of the catalysts.

  12. Nonisostructural complex oxide heteroepitaxy

    SciTech Connect (OSTI)

    Wong, Franklin J. Ramanathan, Shriram

    2014-07-01

    The authors present an overview of the fundamentals and representative examples of the growth of epitaxial complex oxide thin films on structurally dissimilar substrates. The authors will delineate how the details of particular crystal structures and symmetry of different oxide surfaces can be employed for a rational approach to the synthesis of nonisostructural epitaxial heterostructures. The concept of oxygen eutaxy can be widely applied. Materials combinations will be split into three categories, and in all cases the films and substrates occur in different crystal structures: (1) common translational and rotational symmetry between the film and substrate planes; (2) translational symmetry mismatch between the substrates and films that is distinct from a simple mismatch in lattice parameters; and (3) rotational symmetry mismatch. In case (1), in principle single-crystalline thin films can be attained despite the films and substrates possessing different crystal structures. In case (2), antiphase boundaries will be prevalent in the thin films. In case (3), thin-film rotational variants that are joined by tilt boundaries will be present. Diffraction techniques to determine crystallographic alignment and epitaxial variants are discussed, and transmission electron microscopy studies to investigate extended defects in the thin films will also be reviewed. The authors end with open problems in this field regarding the structure of oxide interfaces that can be topics for future research.

  13. Photo-oxidation catalysts

    DOE Patents [OSTI]

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis

    2009-07-14

    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  14. A study of the kinetics and mechanism of the adsorption and anaerobic partial oxidation of n-butane over a vanadyl pyrophosphate catalyst

    SciTech Connect (OSTI)

    Sakakini, B.H.; Taufiq-Yap, Y.H.; Waugh, K.C.

    2000-01-25

    The interaction of n-butane with a ((VO){sub 2}P{sub 2}O{sub 7}) catalyst has been investigated by temperature-programmed desorption and anaerobic temperature-programmed reaction. n-Butane has been shown to adsorb on the (VO){sub 2}P{sub 2}O{sub 7} to as a butyl-hydroxyl pair. When adsorption is carried out at 223 K, upon temperature programming some of the butyl-hydroxyl species recombine resulting in butane desorption at 260 K. However, when adsorption is carried out at 423 K, the hydroxyl species of the butyl-hydroxyl pair migrate away from the butyl species during the adsorption, forming water which is detected in the gas phase. Butane therefore is not observed to desorb at 260 K after the authors lowered the temperature to 223 K under the butane/helium from the adsorption temperature of 423 K prior to temperature programming from that temperature to 1100 K under a helium stream. Anaerobic temperature-programmed oxidation of n-butane produces butene and butadiene at a peak maximum temperature of 1000 K; this is exactly the temperature at which, upon temperature programming, oxygen evolves from the lattice and desorbs as O{sub 2}. This, and the fact that the amount of oxygen desorbing from the (VO){sub 2}P{sub 2}O{sub 7} at {approximately}1000 K is the same as that required for the oxidation of the n-butane to butene and butadiene, strongly suggests (1) that lattice oxygen as it emerges at the surface is the selective oxidant and (2) that its appearance at the surface is the rate-determining step in the selective oxidation of n-butane. The surface of the (VO){sub 2}P{sub 2}O{sub 7} catalyst on which this selective oxidation takes place has had approximately two monolayers of oxygen removed from it by unselective oxidation of the n-butane to CO, CO{sub 2}, and H{sub 2}O between 550 and 950 K and has had approximately one monolayer of carbon deposited on it at {approximately}1000 K. It is apparent, therefore, that the original crystallography of the (VO){sub 2}P

  15. Phase Discrimination through Oxidant Selection for Iron Oxide...

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

    Phase Discrimination through Oxidant Selection for Iron Oxide Ultrathin Films Home > Research > ANSER Research Highlights > Phase Discrimination through Oxidant Selection for Iron...

  16. Nitrous oxide production and methane oxidation by different ammonia-oxidizing bacteria

    SciTech Connect (OSTI)

    Jiang, Q.Q.; Bakken, L.R.

    1999-06-01

    Ammonia-oxidizing bacteria (AOB) are thought to contribute significantly to N{sub 2}O production and methane oxidation in soils. Most knowledge derives from experiments with Nitrosomonas europaea, which appears to be of minor importance in most soils compared to Nitrosospira spp. The authors have conducted a comparative study of levels of aerobic N{sub 2}O production in six phylogenetically different Nitrosospira strains newly isolated from soils and in two N. europaea and Nitrosospira multiformis type strains. The fraction of oxidized ammonium released as N{sub 2}O during aerobic growth was remarkably constant for all the Nitrosospira strains, irrespective of the substrate supply (urea versus ammonium), the pH, or substrate limitation. N. europaea and Nitrosospira multiformis released similar fractions of N{sub 2}O when they were supplied with ample amounts of substrates, but the fractions rose sharply when they were restricted by a low pH or substrate limitation. Phosphate buffer doubled the N{sub 2}O release for all types of AOB. No detectable oxidation of atmospheric methane was detected. Calculations based on detection limits as well as data in the literature on CH{sub 4} oxidation by AOB bacteria prove that none of the tested strains contribute significantly to the oxidation of atmospheric CH{sub 4} in soils.

  17. Mixed Acid Oxidation

    SciTech Connect (OSTI)

    Pierce, R.A.

    1999-10-26

    Several non-thermal processes have been developed to destroy organic waste compounds using chemicals with high oxidation potentials. These efforts have focused on developing technologies that work at low temperatures, relative to incineration, to overcome many of the regulatory issues associated with obtaining permits for waste incinerators. One such technique with great flexibility is mixed acid oxidation. Mixed acid oxidation, developed at the Savannah River Site, uses a mixture of an oxidant (nitric acid) and a carrier acid (phosphoric acid). The carrier acid acts as a non-volatile holding medium for the somewhat volatile oxidant. The combination of acids allows appreciable amounts of the concentrated oxidant to remain in the carrier acid well above the oxidant''s normal boiling point.

  18. Growth control of the oxidation state in vanadium oxide thin...

    Office of Scientific and Technical Information (OSTI)

    Growth control of the oxidation state in vanadium oxide thin films Citation Details In-Document Search Title: Growth control of the oxidation state in vanadium oxide thin films ...

  19. Phase Discrimination through Oxidant Selection for Iron Oxide Ultrathin

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

    Films | ANSER Center | Argonne-Northwestern National Laboratory Phase Discrimination through Oxidant Selection for Iron Oxide Ultrathin Films Home > Research > ANSER Research Highlights > Phase Discrimination through Oxidant Selection for Iron Oxide Ultrathin Films

  20. Catalytic oxidation of hydrocarbons and alcohols by carbon dioxide on oxide catalysts

    SciTech Connect (OSTI)

    Krylov, O.V. . N.N. Semenov Inst. of Chemical Physics); Mamedov, A.Kh.; Mirzabekova, S.R. . Yu.G. Mamedaliev Inst. of Petrochemical Processes)

    1995-02-01

    The great interest displayed lately in heterogeneous catalytic reactions of carbon dioxide is caused by two reasons: (1) the necessity to fight the greenhouse effect and (2) the exhaust of carbon raw material sources. Reactions of oxidative transformation of organic compounds of different classes (alkanes, alkenes, and alcohols) with a nontraditional oxidant, carbon dioxide, were studied on oxide catalysts Fe-O, Cr-O, Mn-O and on multicomponent systems based on manganese oxide. The supported manganese oxide catalysts are active, selective, and stable in conversion of the CH[sub 4] + CO[sub 2] mixture into synthesis gas and in oxidative dehydrogenation of C[sub 2] [minus] C[sub 7] hydrocarbons and the lower alcohols. Unlike metal catalysts manganese oxide based catalysts do not form a carbon layer during the reaction.

  1. Electron density distribution in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides studied by double nuclear magnetic resonance methods

    SciTech Connect (OSTI)

    Piskunov, Yu. V. Ogloblichev, V. V.; Arapova, I. Yu.; Sadykov, A. V.; Gerashchenko, A. P.; Verkhovskii, S. V.

    2011-11-15

    The effect of charge disorder on the formation of an inhomogeneous state of the electron system in the conduction band in BaPb{sub 1-x}Sb{sub x}O{sub 3} superconducting oxides is investigated experimentally by NMR methods. The NMR spectra of {sup 17}O are measured systematically, and the contributions from {sup 17}O atoms with different cation nearest surroundings are identified. It is found that microscopic regions with an elevated spin density of charge carriers are formed within two coordination spheres near antimony ions. Nuclei of the superconducting phase of the oxide (regions with an elevated antimony concentration) microscopically distributed over the sample are detected in compounds with x = 0.25 and 0.33. Experiments in which a double resonance signal of the spin echo of {sup 17}O-{sup 207}Pb and {sup 17}O-{sup 121}Sb are measured in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides are carried out for the first time. The constants of indirect heteronuclear spin-spin {sup 17}O-{sup 207}Pb interaction are determined as functions of the local Knight shift {sub 207}Ks. The estimates of the constants of the indirect interaction between the nuclei of the nearest neighbors (O-Pb and Pb-Pb atoms) and analysis of evolution of the NMR spectra of {sup 17}O upon a change in the antimony concentration are convincing evidence in favor of the development of a microscopically inhomogeneous state of the electron system in the metal phase of BaPb{sub 1-x}Sb{sub x}O{sub 3} oxides.

  2. Solid oxide electrochemical reactor science.

    SciTech Connect (OSTI)

    Sullivan, Neal P.; Stechel, Ellen Beth; Moyer, Connor J.; Ambrosini, Andrea; Key, Robert J.

    2010-09-01

    Solid-oxide electrochemical cells are an exciting new technology. Development of solid-oxide cells (SOCs) has advanced considerable in recent years and continues to progress rapidly. This thesis studies several aspects of SOCs and contributes useful information to their continued development. This LDRD involved a collaboration between Sandia and the Colorado School of Mines (CSM) ins solid-oxide electrochemical reactors targeted at solid oxide electrolyzer cells (SOEC), which are the reverse of solid-oxide fuel cells (SOFC). SOECs complement Sandia's efforts in thermochemical production of alternative fuels. An SOEC technology would co-electrolyze carbon dioxide (CO{sub 2}) with steam at temperatures around 800 C to form synthesis gas (H{sub 2} and CO), which forms the building blocks for a petrochemical substitutes that can be used to power vehicles or in distributed energy platforms. The effort described here concentrates on research concerning catalytic chemistry, charge-transfer chemistry, and optimal cell-architecture. technical scope included computational modeling, materials development, and experimental evaluation. The project engaged the Colorado Fuel Cell Center at CSM through the support of a graduate student (Connor Moyer) at CSM and his advisors (Profs. Robert Kee and Neal Sullivan) in collaboration with Sandia.

  3. Overview of the Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT): mechanistic chamber studies on the oxidation of biogenic compounds

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

    Nguyen, T. B.; Crounse, J. D.; Schwantes, R. H.; Teng, A. P.; Bates, K. H.; Zhang, X.; St. Clair, J. M.; Brune, W. H.; Tyndall, G. S.; Keutsch, F. N.; et al

    2014-12-19

    The Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT) was a collaborative atmospheric chamber campaign that occurred during January 2014. FIXCIT is the laboratory component of a synergistic field and laboratory effort aimed toward (1) better understanding the chemical details behind ambient observations relevant to the southeastern United States, (2) advancing the knowledge of atmospheric oxidation mechanisms of important biogenic hydrocarbons, and (3) characterizing the behavior of field instrumentation using authentic standards. Approximately 20 principal scientists from 14 academic and government institutions performed parallel measurements at a forested site in Alabama and at the atmospheric chambers at Caltech.more » During the 4 week campaign period, a series of chamber experiments was conducted to investigate the dark- and photo-induced oxidation of isoprene, α-pinene, methacrolein, pinonaldehyde, acylperoxy nitrates, isoprene hydroxy nitrates (ISOPN), isoprene hydroxy hydroperoxides (ISOPOOH), and isoprene epoxydiols (IEPOX) in a highly controlled and atmospherically relevant manner. Pinonaldehyde and isomer-specific standards of ISOPN, ISOPOOH, and IEPOX were synthesized and contributed by campaign participants, which enabled explicit exploration into the oxidation mechanisms and instrument responses for these important atmospheric compounds. The present overview describes the goals, experimental design, instrumental techniques, and preliminary observations from the campaign. This work provides context for forthcoming publications affiliated with the FIXCIT campaign. Insights from FIXCIT are anticipated to aid significantly in interpretation of field data and the revision of mechanisms currently implemented in regional and global atmospheric models.« less

  4. Overview of the Focused Isoprene eXperiments at California Institute of Technology (FIXCIT): mechanistic chamber studies on the oxidation of biogenic compounds

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

    Nguyen, T. B.; Crounse, J. D.; Schwantes, R. H.; Teng, A. P.; Bates, K. H.; Zhang, X.; St. Clair, J. M.; Brune, W. H.; Tyndall, G. S.; Keutsch, F. N.; et al

    2014-08-25

    The Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT) was a collaborative atmospheric chamber campaign that occurred during January 2014. FIXCIT was the laboratory component of a synergistic field and laboratory effort aimed toward (1) better understanding the chemical details behind ambient observations relevant to the Southeastern United States, (2) advancing the knowledge of atmospheric oxidation mechanisms of important biogenic hydrocarbons, and (3) characterizing the behavior of field instrumentation using authentic standards. Approximately 20 principal scientists from 14 academic and government institutions performed parallel measurements at a forested site in Alabama and at the atmospheric chambers at Caltech.more » During the four-week campaign period, a series of chamber experiments was conducted to investigate the dark- and photo-induced oxidation of isoprene, α-pinene, methacrolein, pinonaldehyde, acylperoxy nitrates, isoprene hydroxy nitrates (ISOPN), isoprene hydroxy hydroperoxides (ISOPOOH), and isoprene epoxydiols (IEPOX) in a highly-controlled and atmospherically-relevant manner. Pinonaldehyde and isomer-specific standards of ISOPN, ISOPOOH, and IEPOX were synthesized and contributed by campaign participants, which enabled explicit exploration into the oxidation mechanisms and instrument responses for these important atmospheric compounds. The present overview describes the goals, experimental design, instrumental techniques, and preliminary observations from the campaign. Insights from FIXCIT are anticipated to significantly aid in interpretation of field data and the revision of mechanisms currently implemented in regional and global atmospheric models.« less

  5. Partial oxidation catalyst

    DOE Patents [OSTI]

    Krumpelt, Michael; Ahmed, Shabbir; Kumar, Romesh; Doshi, Rajiv

    2000-01-01

    A two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion. The dehydrogenation portion is a group VIII metal and the oxide-ion conducting portion is selected from a ceramic oxide crystallizing in the fluorite or perovskite structure. There is also disclosed a method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

  6. Fundamentals of Mercury Oxidation in Flue Gas

    SciTech Connect (OSTI)

    JoAnn Lighty; Geoffrey Silcox; Constance Senior; Joseph Helble; Balaji Krishnakumar

    2008-07-31

    The objective of this project was to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involved both experimental and modeling efforts. The team was comprised of the University of Utah, Reaction Engineering International, and the University of Connecticut. The objective was to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters studied include HCl, NO{sub x}, and SO{sub 2} concentrations, ash constituents, and temperature. The results suggested that homogeneous mercury oxidation is below 10% which is not consistent with previous data of others and work which was completed early in this research program. Previous data showed oxidation above 10% and up to 100%. However, the previous data are suspect due to apparent oxidation occurring within the sampling system where hypochlorite ion forms in the KCl impinger, which in turn oxidized mercury. Initial tests with entrained iron oxide particles injected into a flame reactor suggest that iron present on fly ash particle surfaces can promote heterogeneous oxidation of mercury in the presence of HCl under entrained flow conditions. Using the data generated above, with homogeneous reactions accounting for less than 10% of the oxidation, comparisons were made to pilot- and full-scale data. The results suggest that heterogeneous reactions, as with the case of iron oxide, and adsorption on solid carbon must be taking place in the full-scale system. Modeling of mercury oxidation using parameters from the literature was conducted to further study the contribution of homogeneous pathways to Hg oxidation in coal combustion systems. Calculations from the literature used rate parameters developed in different studies, in some cases using transition state theory with a range of approaches and basis sets, and in other cases

  7. An experimental study of external reactor vessel cooling strategy on the critical heat flux using the graphene oxide nano-fluid

    SciTech Connect (OSTI)

    Park, S. D.; Lee, S. W.; Kang, S.; Kim, S. M.; Seo, H.; Bang, I. C.

    2012-07-01

    External reactor vessel cooling (ERVC) for in-vessel retention (IVR) of corium as a key severe accident management strategy can be achieved by flooding the reactor cavity during a severe accident. In this accident mitigation strategy, the decay heat removal capability depends on whether the imposed heat flux exceeds critical heat flux (CHF). To provide sufficient cooling for high-power reactors such as APR1400, there have been some R and D efforts to use the reactor vessel with micro-porous coating and nano-fluids boiling-induced coating. The dispersion stability of graphene-oxide nano-fluid in the chemical conditions of flooding water that includes boric acid, lithium hydroxide (LiOH) and tri-sodium phosphate (TSP) was checked in terms of surface charge or zeta potential before the CHF experiments. Results showed that graphene-oxide nano-fluids were very stable under ERVC environment. The critical heat flux (CHF) on the reactor vessel external wall was measured using the small scale two-dimensional slide test section. The radius of the curvature is 0.1 m. The dimension of each part in the facility simulated the APR-1400. The heater was designed to produce the different heat flux. The magnitude of heat flux follows the one of the APR-1400 when the severe accident occurred. All tests were conducted under inlet subcooling 10 K. Graphene-oxide nano-fluids (concentration: 10 -4 V%) enhanced CHF limits up to about 20% at mass flux 50 kg/m{sup 2}s and 100 kg/m{sup 2}s in comparison with the results of the distilled water at same test condition. (authors)

  8. Complex oxides: Intricate disorder

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

    Uberuaga, Blas Pedro

    2016-02-29

    In this study, complex oxides such as pyrochlores have a myriad of potential technological applications, including as fast ion conductors and radiation-tolerant nuclear waste forms. They are also of interest for their catalytic and spin ice properties. Many of these functional properties are enabled by the atomic structure of the cation sublattices. Pyrochlores (A2B2O7) contain two different cations (A and B), typically a 3+ rare earth and a 4+ transition metal such as Hf, Zr, or Ti. The large variety of chemistries that can form pyrochlores leads to a rich space in which to search for exotic new materials. Furthermore,more » how cations order or disorder on their respective sublattices for a given chemical composition influences the functional properties of the oxide. For example, oxygen ionic conductivity is directly correlated with the level of cation disorder — the swapping of A and B cations1. Further, the resistance of these materials against amorphization has also been connected with the ability of the cations to disorder2, 3. These correlations between cation structure and functionality have spurred great interest in the structure of the cation sublattice under irradiation, with significant focus on the disordering mechanisms and disordered structure. Previous studies have found that, upon irradiation, pyrochlores often undergo an order-to-disorder transformation, in which the resulting structure is, from a diffraction point of view, indistinguishable from fluorite (AO2) (ref. 3). Shamblin et al. now reveal that the structure of disordered pyrochlore is more complicated than previously thought4.« less

  9. Barium oxide, calcium oxide, magnesia, and alkali oxide free glass

    DOE Patents [OSTI]

    Lu, Peizhen Kathy; Mahapatra, Manoj Kumar

    2013-09-24

    A glass composition consisting essentially of about 10-45 mole percent of SrO; about 35-75 mole percent SiO.sub.2; one or more compounds from the group of compounds consisting of La.sub.2O.sub.3, Al.sub.2O.sub.3, B.sub.2O.sub.3, and Ni; the La.sub.2O.sub.3 less than about 20 mole percent; the Al.sub.2O.sub.3 less than about 25 mole percent; the B.sub.2O.sub.3 less than about 15 mole percent; and the Ni less than about 5 mole percent. Preferably, the glass is substantially free of barium oxide, calcium oxide, magnesia, and alkali oxide. Preferably, the glass is used as a seal in a solid oxide fuel/electrolyzer cell (SOFC) stack. The SOFC stack comprises a plurality of SOFCs connected by one or more interconnect and manifold materials and sealed by the glass. Preferably, each SOFC comprises an anode, a cathode, and a solid electrolyte.

  10. METAL OXIDE NANOPARTICLES

    SciTech Connect (OSTI)

    FERNANDEZ-GARCIA,M.; RODGRIGUEZ, J.A.

    2007-10-01

    This chapter covers the fundamental science, synthesis, characterization, physicochemical properties and applications of oxide nanomaterials. Explains fundamental aspects that determine the growth and behavior of these systems, briefly examines synthetic procedures using bottom-up and top-down fabrication technologies, discusses the sophisticated experimental techniques and state of the art theory results used to characterize the physico-chemical properties of oxide solids and describe the current knowledge concerning key oxide materials with important technological applications.

  11. Superconductive ceramic oxide combination

    SciTech Connect (OSTI)

    Chatterjee, D.K.; Mehrotra, A.K.; Mir, J.M.

    1991-03-05

    This patent describes the combination of a superconductive ceramic oxide which degrades in conductivity upon contact of ambient air with its surface and, interposed between the ceramic oxide surface and ambient air in the amount of at least 1 mg per square meter of surface area of the superconductive ceramic oxide, a passivant polymer selected from the group consisting of a polyester ionomer and an alkyl cellulose.

  12. OXIDATION OF TRANSURANIC ELEMENTS

    DOE Patents [OSTI]

    Moore, R.L.

    1959-02-17

    A method is reported for oxidizing neptunium or plutonium in the presence of cerous values without also oxidizing the cerous values. The method consists in treating an aqueous 1N nitric acid solution, containing such cerous values together with the trivalent transuranic elements, with a quantity of hydrogen peroxide stoichiometrically sufficient to oxidize the transuranic values to the hexavalent state, and digesting the solution at room temperature.

  13. Comparative XRPD and XAS study of the impact of the synthesis process on the electronic and structural environments of uranium–americium mixed oxides

    SciTech Connect (OSTI)

    Prieur, D.; Lebreton, F.; Somers, J.; Delahaye, T.

    2015-10-15

    Uranium–americium mixed oxides are potential compounds to reduce americium inventory in nuclear waste via a partitioning and transmutation strategy. A thorough assessment of the oxygen-to-metal ratio is paramount in such materials as it determines the important underlying electronic structure and phase relations, affecting both thermal conductivity of the material and its interaction with the cladding and coolant. In 2011, various XAS experiments on U{sub 1−x}Am{sub x}O{sub 2±δ} samples prepared by different synthesis methods have reported contradictory results on the charge distribution of U and Am. This work alleviates this discrepancy. The XAS results confirm that, independently of the synthesis process, the reductive sintering of U{sub 1−x}Am{sub x}O{sub 2±δ} leads to the formation of similar fluorite solid solution indicating the presence of Am{sup +III} and U{sup +V} in equimolar proportions. - Graphical abstract: Formation of (U{sup IV/V},Am{sup III})O{sup 2} solid solution by sol–gel and by powder metallurgy. - Highlights: • Uranium–americium mixed oxides were synthesized by sol–gel and powder metallurgy. • Fluorite solid solutions with similar local environment have been obtained. • U{sup V} and Am{sup III} are formed in equimolar proportions.

  14. Mixed oxide solid solutions

    DOE Patents [OSTI]

    Magno, Scott; Wang, Ruiping; Derouane, Eric

    2003-01-01

    The present invention is a mixed oxide solid solution containing a tetravalent and a pentavalent cation that can be used as a support for a metal combustion catalyst. The invention is furthermore a combustion catalyst containing the mixed oxide solid solution and a method of making the mixed oxide solid solution. The tetravalent cation is zirconium(+4), hafnium(+4) or thorium(+4). In one embodiment, the pentavalent cation is tantalum(+5), niobium(+5) or bismuth(+5). Mixed oxide solid solutions of the present invention exhibit enhanced thermal stability, maintaining relatively high surface areas at high temperatures in the presence of water vapor.

  15. Reducible oxide based catalysts

    DOE Patents [OSTI]

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  16. Stabilized chromium oxide film

    DOE Patents [OSTI]

    Nyaiesh, A.R.; Garwin, E.L.

    1986-08-04

    Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150A are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

  17. Stabilized chromium oxide film

    DOE Patents [OSTI]

    Garwin, Edward L.; Nyaiesh, Ali R.

    1988-01-01

    Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

  18. Remarkable NO oxidation on single supported platinum atoms

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

    Narula, Chaitanya K.; Allard, Lawrence F.; Stocks, G. M.; Moses-DeBusk, Melanie

    2014-11-28

    Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-alumina-supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate our theoretical study, we evaluated single θ-Al2O3-supported platinum atoms and found them to exhibit remarkable NO oxidation activity. A comparison of turnover frequencies (TOF) of single supported Pt atoms with those of platinum particles for NO oxidation shows that single supported Pt atoms aremore » as active as fully formed platinum particles. The overall picture of NO oxidation on supported Pt is that NO oxidation activity decreases with decreasing Pt particle size but accelerates when Pt is present only as single atoms.« less

  19. Dysprosium oxide and dysprosium-oxide-doped titanium oxide thin films grown by atomic layer deposition

    SciTech Connect (OSTI)

    Tamm, Aile Kozlova, Jekaterina; Aarik, Lauri; Aarik, Jaan; Kukli, Kaupo; Link, Joosep; Stern, Raivo

    2015-01-15

    Dysprosium oxide and dysprosium-oxide-doped titanium oxide thin films were grown by atomic layer deposition on silicon substrates. For depositing dysprosium and titanium oxides Dy(thd){sub 3}-O{sub 3} and TiCl{sub 4}-O{sub 3} were used as precursors combinations. Appropriate parameters for Dy(thd){sub 3}-O{sub 3} growth process were obtained by using a quartz crystal microbalance system. The Dy{sub 2}O{sub 3} films were deposited on planar substrates and on three-dimensional substrates with aspect ratio 1:20. The Dy/Ti ratio of Dy{sub 2}O{sub 3}-doped TiO{sub 2} films deposited on a planar silicon substrate ranged from 0.04 to 0.06. Magnetometry studies revealed that saturation of magnetization could not be observed in planar Dy{sub 2}O{sub 3} films, but it was observable in Dy{sub 2}O{sub 3} films on 3D substrates and in doped TiO{sub 2} films with a Dy/Ti atomic ratio of 0.06. The latter films exhibited saturation magnetization 10{sup −6} A cm{sup 2} and coercivity 11 kA/m at room temperature.

  20. Thermal stability in the blended lithium manganese oxide – Lithium nickel cobalt manganese oxide cathode materials: An in situ time-resolved X-Ray diffraction and mass spectroscopy study

    SciTech Connect (OSTI)

    Hu, Enyuan; Bak, Seong Min; Senanayake, Sanjaya D.; Yang, Xiao-Qing; Nam, Kyung-Wan; Zhang, Lulu; Shao, Minhua

    2015-03-01

    Thermal stabilities of a series of blended LiMn2O4(LMO)-LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with different weight ratios were studied by in situ time-resolved X-ray diffraction (XRD) combined with mass spectroscopy in the temperature range of 25°C-580°C under helium atmosphere. Upon heating, the electrochemically delithiated LMO changed into Mn3O4 phase at around 250°C. Formation of MnO with rocksalt structure started at 520°C. This observation is in contrast to the previous report for chemically delithiate LMO in air, in which a process of λ-MnO2 transforming to β-MnO2 was observed. Oxygen peak was not observed in all cases, presumably as a result of either consumption by the carbon or detection limit. CO2 profile correlates well with the phase transition and indirectly suggests the oxygen release of the cathode. Introducing NCM into LMO has two effects: first, it makes the high temperature rock-salt phase formation more complicated with more peaks in CO2 profile due to different MO (M = Ni, Mn, Co) phases; secondly, the onset temperature of CO2 release is lowered, implying lowered oxygen release temperature. Upon heating, XRD patterns indicate the NCM part reacts first, followed by the LMO part. This confirms the better thermal stability of LMO over NCM.

  1. Thermal stability in the blended lithium manganese oxide – Lithium nickel cobalt manganese oxide cathode materials: An in situ time-resolved X-Ray diffraction and mass spectroscopy study

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

    Hu, Enyuan; Bak, Seong Min; Senanayake, Sanjaya D.; Yang, Xiao-Qing; Nam, Kyung-Wan; Zhang, Lulu; Shao, Minhua

    2015-03-01

    Thermal stabilities of a series of blended LiMn2O4(LMO)-LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with different weight ratios were studied by in situ time-resolved X-ray diffraction (XRD) combined with mass spectroscopy in the temperature range of 25°C-580°C under helium atmosphere. Upon heating, the electrochemically delithiated LMO changed into Mn3O4 phase at around 250°C. Formation of MnO with rocksalt structure started at 520°C. This observation is in contrast to the previous report for chemically delithiate LMO in air, in which a process of λ-MnO2 transforming to β-MnO2 was observed. Oxygen peak was not observed in all cases, presumably as a result of either consumptionmore » by the carbon or detection limit. CO2 profile correlates well with the phase transition and indirectly suggests the oxygen release of the cathode. Introducing NCM into LMO has two effects: first, it makes the high temperature rock-salt phase formation more complicated with more peaks in CO2 profile due to different MO (M = Ni, Mn, Co) phases; secondly, the onset temperature of CO2 release is lowered, implying lowered oxygen release temperature. Upon heating, XRD patterns indicate the NCM part reacts first, followed by the LMO part. This confirms the better thermal stability of LMO over NCM.« less

  2. Thermal stability in the blended lithium manganese oxide Lithium nickel cobalt manganese oxide cathode materials: An in situ time-resolved X-Ray diffraction and mass spectroscopy study

    SciTech Connect (OSTI)

    Hu, Enyuan; Bak, Seong Min; Senanayake, Sanjaya D.; Yang, Xiao-Qing; Nam, Kyung-Wan; Zhang, Lulu; Shao, Minhua

    2015-03-01

    Thermal stabilities of a series of blended LiMn2O4(LMO)-LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with different weight ratios were studied by in situ time-resolved X-ray diffraction (XRD) combined with mass spectroscopy in the temperature range of 25C-580C under helium atmosphere. Upon heating, the electrochemically delithiated LMO changed into Mn3O4 phase at around 250C. Formation of MnO with rocksalt structure started at 520C. This observation is in contrast to the previous report for chemically delithiate LMO in air, in which a process of ?-MnO2 transforming to ?-MnO2 was observed. Oxygen peak was not observed in all cases, presumably as a result of either consumption by the carbon or detection limit. CO2 profile correlates well with the phase transition and indirectly suggests the oxygen release of the cathode. Introducing NCM into LMO has two effects: first, it makes the high temperature rock-salt phase formation more complicated with more peaks in CO2 profile due to different MO (M = Ni, Mn, Co) phases; secondly, the onset temperature of CO2 release is lowered, implying lowered oxygen release temperature. Upon heating, XRD patterns indicate the NCM part reacts first, followed by the LMO part. This confirms the better thermal stability of LMO over NCM.

  3. Coal combustion by wet oxidation

    SciTech Connect (OSTI)

    Bettinger, J.A.; Lamparter, R.A.; McDowell, D.C.

    1980-11-15

    The combustion of coal by wet oxidation was studied by the Center for Waste Management Programs, of Michigan Technological University. In wet oxidation a combustible material, such as coal, is reacted with oxygen in the presence of liquid water. The reaction is typically carried out in the range of 204/sup 0/C (400/sup 0/F) to 353/sup 0/C (650/sup 0/F) with sufficient pressure to maintain the water present in the liquid state, and provide the partial pressure of oxygen in the gas phase necessary to carry out the reaction. Experimental studies to explore the key reaction parameters of temperature, time, oxidant, catalyst, coal type, and mesh size were conducted by running batch tests in a one-gallon stirred autoclave. The factors exhibiting the greatest effect on the extent of reaction were temperature and residence time. The effect of temperature was studied from 204/sup 0/C (400/sup 0/F) to 260/sup 0/C (500/sup 0/F) with a residence time from 600 to 3600 seconds. From this data, the reaction activation energy of 2.7 x 10/sup 4/ calories per mole was determined for a high-volatile-A-Bituminous type coal. The reaction rate constant may be determined at any temperature from the activation energy using the Arrhenius equation. Additional data were generated on the effect of mesh size and different coal types. A sample of peat was also tested. Two catalysts were evaluated, and their effects on reaction rate presented in the report. In addition to the high temperature combustion, low temperature desulfurization is discussed. Desulfurization can improve low grade coal to be used in conventional combustion methods. It was found that 90% of the sulfur can be removed from the coal by wet oxidation with the carbon untouched. Further desulfurization studies are indicated.

  4. Strong reduction of V{sup 4+} amount in vanadium oxide/hexadecylamine nanotubes by doping with Co{sup 2+} and Ni{sup 2+} ions: Electron paramagnetic resonance and magnetic studies

    SciTech Connect (OSTI)

    Saleta, M. E.; Troiani, H. E.; Ribeiro Guevara, S.; Ruano, G.; Sanchez, R. D.; Malta, M.; Torresi, R. M.

    2011-05-01

    In this work we present a complete characterization and magnetic study of vanadium oxide/hexadecylamine nanotubes (VO{sub x}/Hexa NT's) doped with Co{sup 2+} and Ni{sup 2+} ions. The morphology of the NT's has been characterized by transmission electron microscopy, while the metallic elements have been quantified by the instrumental neutron activation analysis technique. The static and dynamic magnetic properties were studied by collecting data of magnetization as a function of magnetic field and temperature and by electron paramagnetic resonance. At difference of the majority reports in the literature, we do not observe magnetic dimers in vanadium oxide nanotubes. Also, we observed that the incorporation of metallic ions (Co{sup 2+}, S = 3/2 and Ni{sup 2+}, S = 1) decreases notably the amount of V{sup 4+} ions in the system, from 14-16% (nondoped case) to 2%-4%, with respect to the total vanadium atoms (fact corroborated by XPS experiments) anyway preserving the tubular nanostructure. The method to decrease the amount of V{sup 4+} in the nanotubes improves considerably their potential technological applications as Li-ion batteries cathodes.

  5. NEPTUNIUM OXIDE PROCESSING

    SciTech Connect (OSTI)

    Jordan, J; Watkins, R; Hensel, S

    2009-05-27

    The Savannah River Site's HB-Line Facility completed a campaign in which fifty nine cans of neptunium oxide were produced and shipped to the Idaho National Laboratory in the 9975 shipping container. The neptunium campaign was divided into two parts: Part 1 which consisted of oxide made from H-Canyon neptunium solution which did not require any processing prior to conversion into an oxide, and Part 2 which consisted of oxide made from additional H-Canyon neptunium solutions which required processing to purify the solution prior to conversion into an oxide. The neptunium was received as a nitrate solution and converted to oxide through ion-exchange column extraction, precipitation, and calcination. Numerous processing challenges were encountered in order make a final neptunium oxide product that could be shipped in a 9975 shipping container. Among the challenges overcome was the issue of scale: translating lab scale production into full facility production. The balance between processing efficiency and product quality assurance was addressed during this campaign. Lessons learned from these challenges are applicable to other processing projects.

  6. Electronic structure of graphene oxide and reduced graphene oxide monolayers

    SciTech Connect (OSTI)

    Sutar, D. S.; Singh, Gulbagh; Divakar Botcha, V.

    2012-09-03

    Graphene oxide (GO) monolayers obtained by Langmuir Blodgett route and suitably treated to obtain reduced graphene oxide (RGO) monolayers were studied by photoelectron spectroscopy. Upon reduction of GO to form RGO C1s x-ray photoelectron spectra showed increase in graphitic carbon content, while ultraviolet photoelectron spectra showed increase in intensity corresponding to C2p-{pi} electrons ({approx}3.5 eV). X-ray excited Auger transitions C(KVV) and plasmon energy loss of C1s photoelectrons have been analyzed to elucidate the valence band structure. The effective number of ({pi}+{sigma}) electrons as obtained from energy loss spectra was found to increase by {approx}28% on reduction of GO.

  7. Mixed Oxide Fuel Fabrication Facility

    National Nuclear Security Administration (NNSA)

    0%2A en Mixed Oxide (MOX) Fuel Fabrication Facility http:nnsa.energy.govfieldofficessavannah-river-field-officemixed-oxide-mox-fuel-fabrication-facility

  8. Study on the mechanism of diametral cladding strain and mixed-oxide fuel element breaching in slow-ramp extended overpower transients

    SciTech Connect (OSTI)

    Tomoyuki Uwaba; Seiichiro Maeda; Tomoyasu Mizuno; Melissa C. Teague

    2012-10-01

    Cladding strain caused by fuel/cladding mechanical interaction (FCMI) was evaluated for mixed-oxide fuel elements subjected to 7090% slow-ramp extended overpower transient tests in the experimental breeder reactor II. Calculated transient-induced cladding strains were correlated with cumulative damage fractions (CDFs) using cladding strength correlations. In a breached high-smeared density solid fuel element with low strength cladding, cladding thermal creep strain was significantly increased to approximately half the transient-induced cladding strain that was considered to be caused by the tertiary creep when the CDF was close to the breach criterion (=1.0), with the remaining strain due to instantaneous plastic deformation. In low-smeared density annular fuel elements, FCMI load was significantly mitigated and resulted in little cladding strain. The CDFs of the annular fuel elements were lower than 0.01 at the end of the overpower transient, indicating a substantial margin to breach. A substantial margin to breach was also maintained in a high-smeared density fuel element with high strength cladding.

  9. Photoelectron spectroscopy and theoretical studies of gaseous uranium hexachlorides in different oxidation states: UCl{sub 6}{sup q?} (q = 02)

    SciTech Connect (OSTI)

    Su, Jing; Dau, Phuong D.; Huang, Dao-Ling; Wang, Lai-Sheng; Liu, Hong-Tao; Wei, Fan; Schwarz, W. H. E.; Li, Jun

    2015-04-07

    Uranium chlorides are important in actinide chemistry and nuclear industries, but their chemical bonding and many physical and chemical properties are not well understood yet. Here, we report the first experimental observation of two gaseous uranium hexachloride anions, UCl{sub 6}{sup ?} and UCl{sub 6}{sup 2?}, which are probed by photoelectron spectroscopy in conjunction with quantum chemistry calculations. The electron affinity of UCl{sub 6} is measured for the first time as +5.3 eV; its second electron affinity is measured to be +0.60 eV from the photoelectron spectra of UCl{sub 6}{sup 2?}. We observe that the detachment cross sections of the 5f electrons are extremely weak in the visible and UV energy ranges. It is found that the one-electron one-determinental molecular orbital picture and Koopmans theorem break down for the strongly internally correlated U-5f{sup 2} valence shell of tetravalent U{sup +4} in UCl{sub 6}{sup 2?}. The calculated adiabatic and vertical electron detachment energies from ab initio calculations agree well with the experimental observations. Electronic structure and chemical bonding in the uranium hexachloride species UCl{sub 6}{sup 2?} to UCl{sub 6} are discussed as a function of the oxidation state of U.

  10. Quantifying electronic correlation strength in a complex oxide: a combined DMFT and ARPES study of LaNiO{sub 3}

    SciTech Connect (OSTI)

    Nowadnick, E. A.; Ruf, J. P.; Park, H.; King, P. D. C.; Schlom, D. G.; Shen, K. M.; Millis, A. J.

    2015-12-07

    The electronic correlation strength is a basic quantity that characterizes the physical properties of materials such as transition metal oxides. Determining correlation strengths requires both precise definitions and a careful comparison between experiment and theory. In this paper, we define the correlation strength via the magnitude of the electron self-energy near the Fermi level. For the case of LaNiO3, we obtain both the experimental and theoretical mass enhancements m/m by considering high resolution angle-resolved photoemission spectroscopy (ARPES) measurements and density functional+dynamical mean field theory (DFT+DMFT) calculations.We use valence-band photoemission data to constrain the free parameters in the theory and demonstrate a quantitative agreement between the experiment and theory when both the realistic crystal structure and strong electronic correlations are taken into account. In addition, by considering DFT+DMFT calculations on epitaxially strained LaNiO3, we find a strain-induced evolution of m/m in qualitative agreement with trends derived from optics experiments. These results provide a benchmark for the accuracy of the DFT+DMFT theoretical approach, and can serve as a test case when considering other complex materials. By establishing the level of accuracy of the theory, this work also will enable better quantitative predictions when engineering new emergent properties in nickelate heterostructures.

  11. Detailed chemical kinetic model for ethanol oxidation (Technical...

    Office of Scientific and Technical Information (OSTI)

    from a constant volume bomb, ignition delay data behind reflected shock waves, and ethanol oxidation product profiles from a turbulent flow reactor were used in this study. ...

  12. Oxide-Nanoparticle Containing Coatings for High Temperature Alloys

    SciTech Connect (OSTI)

    2009-04-01

    This factsheet describes a study whose objective is to examine the feasibility of using Electromagnetic Stirring (EMS) techniques in dispersing the oxide nanoparticles uniformly within the liquid steel.

  13. Oxidative Tritium Decontamination System

    DOE Patents [OSTI]

    Gentile, Charles A. , Guttadora, Gregory L. , Parker, John J.

    2006-02-07

    The Oxidative Tritium Decontamination System, OTDS, provides a method and apparatus for reduction of tritium surface contamination on various items. The OTDS employs ozone gas as oxidizing agent to convert elemental tritium to tritium oxide. Tritium oxide vapor and excess ozone gas is purged from the OTDS, for discharge to atmosphere or transport to further process. An effluent stream is subjected to a catalytic process for the decomposition of excess ozone to diatomic oxygen. One of two configurations of the OTDS is employed: dynamic apparatus equipped with agitation mechanism and large volumetric capacity for decontamination of light items, or static apparatus equipped with pressurization and evacuation capability for decontamination of heavier, delicate, and/or valuable items.

  14. Project Profile: High Performance Reduction/Oxidation Metal Oxides for

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

    Thermochemical Energy Storage | Department of Energy Project Profile: High Performance Reduction/Oxidation Metal Oxides for Thermochemical Energy Storage Project Profile: High Performance Reduction/Oxidation Metal Oxides for Thermochemical Energy Storage Sandia National Laboratory Logo Sandia National Lab (Sandia), through the Concentrating Solar Power: Efficiently Leveraging Equilibrium Mechanisms for Engineering New Thermochemical Storage (CSP: ELEMENTS) funding program, is systematically

  15. Thin films of metal oxides on metal single crystals: Structure and growth by scanning tunneling microscopy

    SciTech Connect (OSTI)

    Galloway, H.C.

    1995-12-01

    Detailed studies of the growth and structure of thin films of metal oxides grown on metal single crystal surfaces using Scanning Tunneling Microscopy (STM) are presented. The oxide overlayer systems studied are iron oxide and titanium oxide on the Pt(III) surface. The complexity of the metal oxides and large lattice mismatches often lead to surface structures with large unit cells. These are particularly suited to a local real space technique such as scanning tunneling microscopy. In particular, the symmetry that is directly observed with the STM elucidates the relationship of the oxide overlayers to the substrate as well as distinguishing, the structures of different oxides.

  16. Metal atom oxidation laser

    DOE Patents [OSTI]

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides. (auth)

  17. Metal atom oxidation laser

    DOE Patents [OSTI]

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides.

  18. Controlled CO preferential oxidation

    DOE Patents [OSTI]

    Meltser, M.A.; Hoch, M.M.

    1997-06-10

    Method is described for controlling the supply of air to a PROX (PReferential OXidation for CO cleanup) reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference there between correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference. 2 figs.

  19. Studies on phase formation, microstructure development and elastic properties of reduced NiO-8YSZ anode supported bi-layer half-cell structures of solid oxide fuel cells

    SciTech Connect (OSTI)

    Nithyanantham, T.; Biswas, S.; Thangavel, S.N.; Bandopadhyay, S.

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Detailed study on the development of microstructure and phase in NiO-8YSZ anodes. Black-Right-Pointing-Pointer Detailed study on elastic properties at high temperatures in air/reducing atmosphere. Black-Right-Pointing-Pointer Effects of initial porosity, composition and other issues are evaluated in detail. -- Abstract: Half-cell structures of solid oxide fuel cells (SOFCs) with a thin and dense electrolyte layer of 8YSZ supported by a thick and porous NiO-8YSZ anode precursor structure were reduced in a gas mixture of 5% H{sub 2}-95% Ar at 800 Degree-Sign C for selected time periods in order to fabricate cermets with desired microstructure and composition, and to study their effects on the elastic properties at ambient and reactive atmospheres. It appears that 2 h of exposure to the reducing conditions is enough to reduce {approx}80% of NiO with an enhanced porosity value of 35%. The Ni-8YSZ cermet phase formation in the anode was analyzed with X-ray diffraction (XRD) in correlation with its microstructure. The elastic properties were determined after the reduction, at room and elevated temperatures using the impulse excitation technique. At room temperature the decrease in the Young's modulus was about 44% (after 8 h of reduction) and can be attributed mainly to the changes in the microstructure, particularly the increase in porosity from {approx}12% to 37%. Young's moduli of the as-received precursor and reduced anodes were evaluated as a function of temperature in air and reducing atmosphere. The results were explained in correlation to the initial porosity, composition and oxidation of Ni at the elevated temperatures.

  20. Analysis of uranium oxide weathering by molecular spectroscopy. Final report

    SciTech Connect (OSTI)

    Zickafoose, M.S.

    1997-11-01

    A preliminary study of the weathering of uranium oxide particles diluted in diamond dust at ambient environmental conditions is presented. The primary weathering reaction is oxidation of the uranium from the +4 to +6 oxidation state, although formation of compounds such as carbonates and hydroxides is possible. Identification of the state of uranium oxide has been attempted using luminescence spectroscopy and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). Luminescence spectra of nominal samples of three common oxides, UO3, U3O8, and UO2, have been measured showing significant spectral differences in peaks at 494 nm, 507 nm, 529 nm, and 553 nm. DRIFTS spectra of the same three oxides show significant differences in peaks at 960 /cm, 856 /cm, and 754 /cm. The differences in these peaks allow determination of the oxidation to the +6 state in these compounds.

  1. 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).

  2. Nucleation and growth of oxide islands during the initial-stage oxidation of (100)Cu-Pt alloys

    SciTech Connect (OSTI)

    Luo, Langli; Zhou, Guangwen; Kang, Yihong; Yang, Judith C.

    2015-02-14

    The initial-stage oxidation of (100) Cu-Pt alloys has been examined by in situ environmental transmission electron microscopy and ex situ atomic force microscopy (AFM). It is shown that the oxidation proceeds via the nucleation and growth of Cu{sub 2}O islands that show dependence on the alloy composition and oxidation temperature. The kinetic measurements on the oxide nucleation reveal that both the nucleation density and surface coverage of Cu{sub 2}O islands can be promoted by alloying more Pt in the Cu-Pt alloys. Increasing the oxidation temperature above 700 °C results in the growth of large Cu{sub 2}O islands that transits to a dendritic growth morphology. The ex situ AFM studies reveal that the nucleation of oxide islands can occur on surface terraces and the subsequent oxide growth depletes local terrace Cu atoms that results in the formation of surface pits.

  3. Methanol partial oxidation reformer

    DOE Patents [OSTI]

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-24

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  4. Methanol partial oxidation reformer

    DOE Patents [OSTI]

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  5. Methanol partial oxidation reformer

    DOE Patents [OSTI]

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-17

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  6. Methanol partial oxidation reformer

    DOE Patents [OSTI]

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    2001-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  7. Mixed Oxide Fuel Fabrication Facility | National Nuclear Security

    National Nuclear Security Administration (NNSA)

    Administration Mixed Oxide Fuel Fabrication Facility Mixed Oxide (MOX) Fuel Fabrication Facility Documents related to the project: Plutonium Disposition Study Options Independent Assessment Phase 1 Report, April 13, 2015 Plutonium Disposition Study Options Independent Assessment Phase 2 Report, August 20, 2015 Final Report of the Plutonium Disposition Red Team, August 13, 2015 Commentary on

  8. The burnup dependence of light water reactor spent fuel oxidation

    SciTech Connect (OSTI)

    Hanson, B.D.

    1998-07-01

    Over the temperature range of interest for dry storage or for placement of spent fuel in a permanent repository under the conditions now being considered, UO{sub 2} is thermodynamically unstable with respect to oxidation to higher oxides. The multiple valence states of uranium allow for the accommodation of interstitial oxygen atoms in the fuel matrix. A variety of stoichiometric and nonstoichiometric phases is therefore possible as the fuel oxidizers from UO{sub 2} to higher oxides. The oxidation of UO{sub 2} has been studied extensively for over 40 years. It has been shown that spent fuel and unirradiated UO{sub 2} oxidize via different mechanisms and at different rates. The oxidation of LWR spent fuel from UO{sub 2} to UO{sub 2.4} was studied previously and is reasonably well understood. The study presented here was initiated to determine the mechanism and rate of oxidation from UO{sub 2.4} to higher oxides. During the early stages of this work, a large variability in the oxidation behavior of samples oxidized under nearly identical conditions was found. Based on previous work on the effect of dopants on UO{sub 2} oxidation and this initial variability, it was hypothesized that the substitution of fission product and actinide impurities for uranium atoms in the spent fuel matrix was the cause of the variable oxidation behavior. Since the impurity concentration is roughly proportional to the burnup of a specimen, the oxidation behavior of spent fuel was expected to be a function of both temperature and burnup. This report (1) summarizes the previous oxidation work for both unirradiated UO{sub 2} and spent fuel (Section 2.2) and presents the theoretical basis for the burnup (i.e., impurity concentration) dependence of the rate of oxidation (Sections 2.3, 2.4, and 2.5), (2) describes the experimental approach (Section 3) and results (Section 4) for the current oxidation tests on spent fuel, and (3) establishes a simple model to determine the activation energies

  9. Thermally Oxidized Silicon

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

    4 Anneli Munkholm (Lumileds Lighting) and Sean Brennan (SSRL) Illustration of the silicon positions near the Si-SiO2 interface for a 4° miscut projected onto the ( ) plane. The silicon atoms in the substrate are blue and those in the oxide are red. The small black spots represent the translated silicon positions in the absence of static disorder. The silicon atoms in the oxide have been randomly assigned a magnitude and direction based on the static disorder value at that position in the

  10. Tetraalykylammonium polyoxoanionic oxidation catalysts

    DOE Patents [OSTI]

    Ellis, Paul E. (Downingtown, PA); Lyons, James E. (Wallingford, PA); Myers, Jr., Harry K. (Cochranville, PA); Shaikh, Shahid N. (Media, PA)

    1998-01-01

    Alkanes are catalytically oxidized in air or oxygen using iron-substituted polyoxoanions (POAs) of the formula: H.sub.e-z (n-C.sub.4 H.sub.9).sub.4 N!.sub.z (XM.sub.11 M'O.sub.39).sup.-e The M' (e.g., iron(III)/iron(II)) reduction potential of the POAs is affected by selection of the central atom X and the framework metal M, and by the number of tetrabutyl-ammonium groups. Decreased Fe(III)/Fe(II) reduction potential has been found to correlate to increased oxidation activity.

  11. Tetraalklylammonium polyoxoanionic oxidation catalysts

    DOE Patents [OSTI]

    Ellis, P.E.; Lyons, J.E.; Myers, H.K. Jr.; Shaikh, S.N.

    1998-10-06

    Alkanes are catalytically oxidized in air or oxygen using iron-substituted polyoxoanions (POAs) of the formula: H{sub e{minus}z}[(n-C{sub 4}H{sub 9}){sub 4}N]{sub z}(XM{sub 11}M{prime}O{sub 39}){sup {minus}e}. The M{prime} (e.g., iron(III)/iron(II)) reduction potential of the POAs is affected by selection of the central atom X and the framework metal M, and by the number of tetrabutyl-ammonium groups. Decreased Fe(III)/Fe(II) reduction potential has been found to correlate to increased oxidation activity.

  12. Tetraalykylammonium polyoxoanionic oxidation catalysts

    DOE Patents [OSTI]

    Ellis, Paul E.; Lyons, James E.; Myers, Jr., Harry K.; Shaikh, Shahid N.

    1998-01-01

    Alkanes are catalytically oxidized in air or oxygen using iron-substituted polyoxoanions (POAs) of the formula: H.sub.e-z ›(n-C.sub.4 H.sub.9).sub.4 N!.sub.z (XM.sub.11 M'O.sub.39).sup.-e The M' (e.g., iron(III)/iron(II)) reduction potential of the POAs is affected by selection of the central atom X and the framework metal M, and by the number of tetrabutyl-ammonium groups. Decreased Fe(III)/Fe(II) reduction potential has been found to correlate to increased oxidation activity.

  13. Molecular water oxidation catalyst

    DOE Patents [OSTI]

    Gratzel, Michael; Munavalli, Shekhar; Pern, Fu-Jann; Frank, Arthur J.

    1993-01-01

    A dimeric composition of the formula: ##STR1## wherein L', L", L'", and L"" are each a bidentate ligand having at least one functional substituent, the ligand selected from bipyridine, phenanthroline, 2-phenylpyridine, bipyrimidine, and bipyrazyl and the functional substituent selected from carboxylic acid, ester, amide, halogenide, anhydride, acyl ketone, alkyl ketone, acid chloride, sulfonic acid, phosphonic acid, and nitro and nitroso groups. An electrochemical oxidation process for the production of the above functionally substituted bidentate ligand diaqua oxo-bridged ruthenium dimers and their use as water oxidation catalysts is described.

  14. Magnetism of cuprate oxides

    SciTech Connect (OSTI)

    Shirane, G.

    1996-11-01

    A review is given of current neutron scattering experiments on cuprate oxides. We first discuss the extensive neutron measurements on high-Tc oxides: La{sub 2-x}Sr{sub x}CuO{sub 4} and related (La{sub 1.6-x}Nd{sub 0.4})Sr{sub x}CuO{sub 4}. The second topic is the spin- Peierls system Cu{sub 1-x}Zn{sub x}GeO{sub 3}, where a new type of antiferromagnetic phase has been discovered. 17 refs, 8 figs.

  15. A Porphyrin-Stabilized Iridium Oxide Water Oxidation Catalyst

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

    Authors: Sherman, B. D., Pillai, S., Kodis, G., Bergkamp, J., Mallouk, T. E., Gust, D., Moore, T. A., and Moore, A. L. Title: A Porphyrin-Stabilized Iridium Oxide Water Oxidation...

  16. An ab initio study of the electronic structure of the boron oxide neutral (BO), cationic (BO{sup +}), and anionic (BO{sup ?}) species

    SciTech Connect (OSTI)

    Magoulas, Ilias; Kalemos, Apostolos

    2014-09-28

    The BO neutral, cationic, and anionic molecular species have been painstakingly studied through multireference configuration interaction and single reference coupled cluster methods employing basis sets of quintuple cardinality. Potential energy curves have been constructed for 38 (BO), 37 (BO{sup +}), and 12 (BO{sup ?}) states and the usual molecular parameters have been extracted most of which are in very good agreement with the scarce experimental data. Numerous avoided crossings appear on more or less all of the studied states of the neutral and cationic species challenging the validity of the Born Oppenheimer approximation. Finally, all excited states of the anionic system lie above the ground state of the neutral BO system and are therefore resonances.

  17. Microsoft Word - SoS abstract-bio_template.doc

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

    and the Social Brain Dr. Michael Graziano Professor of Psychology, Princeton University Princeton New Jersey ABSTRACT: What is consciousness and how can a brain, a mere ...

  18. Highly oxidized superconductors

    DOE Patents [OSTI]

    Morris, D.E.

    1994-09-20

    Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known synthesis in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed. 16 figs.

  19. Conformations of organophosphine oxides

    SciTech Connect (OSTI)

    De Silva, Nuwan; Zahariev, Federico; Hay, Benjamin P.; Gordon, Mark S.; Windus, Theresa L.

    2015-07-17

    The conformations of a series of organophosphine oxides, OP(CH3)2R, where R = methyl, ethyl, isopropyl, tert-butyl, vinyl, and phenyl, are predicted using the MP2/cc-pVTZ level of theory. Comparison of potential energy surfaces for rotation about P–C bonds with crystal structure data reveals a strong correlation between predicted location and energetics of minima and histograms of dihedral angle distributions observed in the solid state. In addition, the most stable conformers are those that minimize the extent of steric repulsion between adjacent rotor substituents, and the torsional barriers tend to increase with the steric bulk of the rotating alkyl group. MM3 force field parameters were adjusted to fit the MP2 results, providing a fast and accurate model for predicting organophosphine oxides shapes—an essential part of understanding the chemistry of these compounds. As a result, the predictive power of the modified MM3 model was tested against MP2/cc-pVTZ conformations for triethylphosphine oxide, OP(CH2CH3)3, and triphenylphosphine oxide, OP(Ph)3.

  20. Conformations of organophosphine oxides

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

    De Silva, Nuwan; Zahariev, Federico; Hay, Benjamin P.; Gordon, Mark S.; Windus, Theresa L.

    2015-07-17

    The conformations of a series of organophosphine oxides, OP(CH3)2R, where R = methyl, ethyl, isopropyl, tert-butyl, vinyl, and phenyl, are predicted using the MP2/cc-pVTZ level of theory. Comparison of potential energy surfaces for rotation about P–C bonds with crystal structure data reveals a strong correlation between predicted location and energetics of minima and histograms of dihedral angle distributions observed in the solid state. In addition, the most stable conformers are those that minimize the extent of steric repulsion between adjacent rotor substituents, and the torsional barriers tend to increase with the steric bulk of the rotating alkyl group. MM3 forcemore » field parameters were adjusted to fit the MP2 results, providing a fast and accurate model for predicting organophosphine oxides shapes—an essential part of understanding the chemistry of these compounds. As a result, the predictive power of the modified MM3 model was tested against MP2/cc-pVTZ conformations for triethylphosphine oxide, OP(CH2CH3)3, and triphenylphosphine oxide, OP(Ph)3.« less

  1. Doped zinc oxide microspheres

    DOE Patents [OSTI]

    Arnold, Jr., Wesley D.; Bond, Walter D.; Lauf, Robert J.

    1993-01-01

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

  2. Doped zinc oxide microspheres

    DOE Patents [OSTI]

    Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

    1993-12-14

    A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

  3. Highly oxidized superconductors

    DOE Patents [OSTI]

    Morris, Donald E.

    1994-01-01

    Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known syntheses in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed.

  4. Nanostructured transition metal oxides useful for water oxidation catalysis

    DOE Patents [OSTI]

    Frei, Heinz M; Jiao, Feng

    2013-12-24

    The present invention provides for a composition comprising a nanostructured transition metal oxide capable of oxidizing two H.sub.2O molecules to obtain four protons. In some embodiments of the invention, the composition further comprises a porous matrix wherein the nanocluster of the transition metal oxide is embedded on and/or in the porous matrix.

  5. Oxidation kinetics of calcium-doped palladium powders

    SciTech Connect (OSTI)

    Jain, S.; Kodas, T.T.; Hampden-Smith, M. [Univ. of New Mexico, Albuquerque, NM (United States)

    1997-04-01

    The oxidation kinetics of submicron Ca-containing Pd powders produced by spray pyrolysis were studied in the temperature range 600 to 675 C using thermogravimetric analysis. The oxidation of pure Pd powder had an activation energy of {approximately}230 kJ/mol in the region 27% < oxidation < 70% and 65 kJ/mol for oxidation > 70%. The activation energies for Pd particles containing 0.01 weight percent (w/o) and 0.4 w/o Ca in the region 27% < oxidation < 70% were {approximately}230 kJ/mol and {approximately}50 kJ/mol, respectively. Transmission electron microscopy suggested that the conversion of Pd to Pd{sup II}O (stoichiometric PdO) proceeds from the particle surface into the interior and not homogeneously throughout the particle. The predictions of a variety of models and rate laws (shrinking core, parabolic, cubic, logarithmic, and inverse logarithmic) were compared with the data. The comparison suggested a mechanism in which oxidation of pure Pd proceeds by chemisorption and diffusion of oxygen to form a substoichiometric oxide, followed by the conversion of substoichiometric PdO to Pd{sup II}O. Oxidation of pure Pd is then probably limited by the diffusion of oxygen through the substoichiometric PdO and/or Pd{sup II}O. The addition of Ca increased the oxidation resistance of Pd most likely by inhibiting oxygen diffusion through the metal oxide layers surrounding the Pd.

  6. Staged membrane oxidation reactor system

    DOE Patents [OSTI]

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2012-09-11

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  7. Staged membrane oxidation reactor system

    DOE Patents [OSTI]

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2013-04-16

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  8. Staged membrane oxidation reactor system

    DOE Patents [OSTI]

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2014-05-20

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  9. Size Effect of Ruthenium Nanoparticles in Catalytic Carbon Monoxide Oxidation

    SciTech Connect (OSTI)

    Joo, Sang Hoon; Park, Jeong Y.; Renzas, J. Russell; Butcher, Derek R.; Huang, Wenyu; Somorjai, Gabor A.

    2010-04-04

    Carbon monoxide oxidation over ruthenium catalysts has shown an unusual catalytic behavior. Here we report a particle size effect on CO oxidation over Ru nanoparticle (NP) catalysts. Uniform Ru NPs with a tunable particle size from 2 to 6 nm were synthesized by a polyol reduction of Ru(acac){sub 3} precursor in the presence of poly(vinylpyrrolidone) stabilizer. The measurement of catalytic activity of CO oxidation over two-dimensional Ru NPs arrays under oxidizing reaction conditions (40 Torr CO and 100 Torr O{sub 2}) showed an activity dependence on the Ru NP size. The CO oxidation activity increases with NP size, and the 6 nm Ru NP catalyst shows 8-fold higher activity than the 2 nm catalysts. The results gained from this study will provide the scientific basis for future design of Ru-based oxidation catalysts.

  10. Looking at Transistor Gate Oxide Formation in Real Time

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

    Looking at Transistor Gate Oxide Formation in Real Time Looking at Transistor Gate Oxide Formation in Real Time Print Wednesday, 25 June 2008 00:00 The oxide gate layer is critical to every transistor, and present-day layer thicknesses are in the 10-20 Å range (1-2 nm). However, little information exists on the oxidation process at this thickness. Available results are either for thicker layers grown under high-pressure conditions or for only the first couple of monolayers studied under

  11. Anodic oxidation of sulfide ions in molten lithium fluoride

    SciTech Connect (OSTI)

    Lloyd, C.L.; Gilbert, J.B. II . Applied Research Lab.)

    1994-10-01

    The study of sulfur and sulfide oxidation in molten salt systems is of current interest in high energy battery, and metallurgical applications. Cyclic voltammetry experiments have been performed on lithium sulfide in a lithium fluoride electrolyte at 1,161 K using a graphite working electrode and a platinum quasi-reference electrode. Two distinct oxidation mechanisms are observed for the sulfide ions. The first oxidation produces sulfur and at a higher potential a disulfide species is proposed to have formed. Both oxidations appear to be reversible and diffusion controlled.

  12. Doped palladium containing oxidation catalysts

    DOE Patents [OSTI]

    Mohajeri, Nahid

    2014-02-18

    A supported oxidation catalyst includes a support having a metal oxide or metal salt, and mixed metal particles thereon. The mixed metal particles include first particles including a palladium compound, and second particles including a precious metal group (PMG) metal or PMG metal compound, wherein the PMG metal is not palladium. The oxidation catalyst may also be used as a gas sensor.

  13. Enzymatic Oxidation of Methane

    SciTech Connect (OSTI)

    Sirajuddin, S; Rosenzweig, AC

    2015-04-14

    Methane monooxygenases (MMOs) are enzymes that catalyze the oxidation of methane to methanol in methanotrophic bacteria. As potential targets for new gas-to-liquid methane bioconversion processes, MMOs have attracted intense attention in recent years. There are two distinct types of MMO, a soluble, cytoplasmic MMO (sMMO) and a membrane-bound, particulate MMO (pMMO). Both oxidize methane at metal centers within a complex, multisubunit scaffold, but the structures, active sites, and chemical mechanisms are completely different. This Current Topic review article focuses on the overall architectures, active site structures, substrate reactivities, proteinprotein interactions, and chemical mechanisms of both MMOs, with an emphasis on fundamental aspects. In addition, recent advances, including new details of interactions between the sMMO components, characterization of sMMO intermediates, and progress toward understanding the pMMO metal centers are highlighted. The work summarized here provides a guide for those interested in exploiting MMOs for biotechnological applications.

  14. Millisecond Oxidation of Alkanes

    Broader source: Energy.gov [DOE]

    This factsheet describes a project whose goal is to commercialize a production process for propylene and acrylic acid from propane using a catalytic auto-thermal oxydehydrogenation process operating at short contact times. Auto-thermal oxidation for conversion of propane to propylene and acrylic acid promises energy savings of 20 trillion Btu per year by 2020. In addition to reducing energy consumption, this technology can reduce manufacturing costs by up to 25 percent, and reduce a variety of greenhouse gas emissions.

  15. Controlled CO preferential oxidation

    DOE Patents [OSTI]

    Meltser, Mark A.; Hoch, Martin M.

    1997-01-01

    Method for controlling the supply of air to a PROX reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference therebetween correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference.

  16. Supercritical water oxidation of ammonium picrate

    SciTech Connect (OSTI)

    LaJeunesse, C.A.; Mills, B.E.; Brown, B.G.

    1994-11-01

    This study demonstrates the feasibility of using supercritical water oxidation to destroy ammonium picrate. Analyses of reactor effluent composition at various temperatures, residence times, and oxidant concentrations were used to design an improved reactor configuration for achieving destruction with minimum corrosion. The engineering evaluation reactor, a room-sized laboratory scale reactor, was reconfigured to incorporate this design change. Destruction of ammonium picrate with minimized corrosion was demonstrated on this reconfigured reactor. Factors that must be considered in scaling up to pilot plant size are discussed.

  17. Water Clustering on Nanostructured Iron Oxide Films

    SciTech Connect (OSTI)

    Merte, L. R.; Bechstein, Ralf; Peng, Guowen; Rieboldt, Felix; Farberow, Carrie A.; Zeuthen, Helene; Knudsen, Jan; Laegsgaard, E.; Wendt, Stefen; Mavrikakis, Manos; Besenbacher, Fleming

    2014-06-30

    The adhesion of water to solid surfaces is characterized by the tendency to balance competing moleculemolecule and moleculesurface interactions. Hydroxyl groups form strong hydrogen bonds to water molecules and are known to substantially influence the wetting behaviour of oxide surfaces, but it is not well-understood how these hydroxyl groups and their distribution on a surface affect the molecular-scale structure at the interface. Here we report a study of water clustering on a moire-structured iron oxide thin film with a controlled density of hydroxyl groups. While large amorphous monolayer islands form on the are film, the hydroxylated iron oxide film acts as a hydrophilic nanotemplate, causing the formation of a regular array of ice-like hexameric nanoclusters. The formation of this ordered phase is localized at the nanometre scale; with increasing water coverage, ordered and amorphous water are found to coexist at adjacent hydroxylated and hydroxyl-free domains of the moire structure.

  18. Tape casting of magnesium oxide.

    SciTech Connect (OSTI)

    Ayala, Alicia; Corral, Erica L.; Loehman, Ronald E.; Bencoe, Denise Nora; Reiterer, Markus; Shah, Raja A.

    2008-02-01

    A tape casting procedure for fabricating ceramic magnesium oxide tapes has been developed as a method to produce flat sheets of sintered MgO that are thin and porous. Thickness of single layer tapes is in the range of 200-400 {micro}m with corresponding surface roughness values in the range of 10-20 {micro}m as measured by laser profilometry. Development of the tape casting technique required optimization of pretreatment for the starting magnesium oxide (MgO) powder as well as a detailed study of the casting slurry preparation and subsequent heat treatments for sintering and final tape flattening. Milling time of the ceramic powder, plasticizer, and binder mixture was identified as a primary factor affecting surface morphology of the tapes. In general, longer milling times resulted in green tapes with a noticeably smoother surface. This work demonstrates that meticulous control of the entire tape casting operation is necessary to obtain high-quality MgO tapes.

  19. The role of fuel-borne catalyst in diesel particulate oxidation behavior

    SciTech Connect (OSTI)

    Song, Juhun; Boehman, Andre L.; Wang, Jinguo

    2006-07-15

    This study addresses the difference in oxidation behavior of diesel particulates at two different load conditions with and without incorporated metal oxides from an iron-based fuel-borne catalyst (FBC). High-resolution transmission electron microscopy imaging, together with electron energy loss spectroscopy is used to evaluate the microstructure and chemical state of the metal oxides that occur during soot formation and to understand the manner in which these properties can affect subsequent soot oxidation. The results here show that FBC-doped soot at low load is more likely to have enrichment of metal oxide on the outer periphery of the soot surface than FBC-doped soot at high load. From element microanalysis, a higher ratio of metal oxide to carbon was observed with FBC-doped soot at low load. Oxidation results indicate that the higher oxidative reactivity is associated with better spreading of the metal oxide on the soot surface. (author)

  20. Kinetics of wet oxidation of propionic and 3-hydroxypropionic acids

    SciTech Connect (OSTI)

    Shende, R.V.; Levec, J.

    1999-07-01

    Oxidation of aqueous solutions of 3-hydroxypropionic (3-HPA) and propionic acids (PA) was studied in a titanium high-pressure reactor at 280--310 C using oxygen partial pressures between 10 and 45 bar. Oxidation of both acids was found to obey first-order kinetic with respect to their concentrations as well as to their lumped TOC concentrations. Oxidation rate revealed a half order dependence with respect to oxygen for oxidation of both acids. In the case of 3-HPA oxidation, the activation energy was found to be 135 kJ/mol, and it was 140 kJ/mol when lumped concentration TOC was used. The activation energy for PA oxidation is 150 kJ/mol, and it is slightly higher, 158 kJ/mol, for TOC reduction. Almost complete conversion of 3-HPA was achieved at 300 C after 1 h, whereas 95% conversion of PA acid was obtained at 310 C after 3 h. During oxidation of 3-HPA, 3-oxopropionic and acetic acids were identified as intermediate products. Oxidation of PA yielded acetic and formic acids as intermediates; at oxygen partial pressures above 25 bar and 310 C, the formation of acetic acid was appreciably reduced. In both cases, however, direct oxidation to carbon dioxide and water was found to be the main reaction route.

  1. Oxidation of step edges on vicinal 4H-SiC(0001) surfaces

    SciTech Connect (OSTI)

    Li, Wenbo; Zhu, Qiaozhi; Wang, Dejun, E-mail: dwang121@dlut.edu.cn [School of Electronic Science and Technology, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China)] [School of Electronic Science and Technology, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Zhao, Jijun [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), College of Advanced Science and Technology, Ministry of Education, Dalian 116024 (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), College of Advanced Science and Technology, Ministry of Education, Dalian 116024 (China)

    2013-11-18

    The oxidation processes of stepped SiC(0001) surfaces are studied within the ab initio atomistic thermodynamics approach. Our calculations show that a one-dimensional -Si-O- chain structure as a precursor for oxide growth on stepped SiC surfaces is formed along the step edge, promoting further oxidation of the step edges. Following the modified Deal-Grove oxidation model, we also find that the oxidation rate at steps is higher than that at terraces by three orders of magnitude. These findings give a reasonable explanation for the oxide thickness fluctuation between the step and the terrace observed in the previous experiments.

  2. Advanced materials for solid oxide fuel cells: Hafnium-Praseodymium-Indium Oxide System

    SciTech Connect (OSTI)

    Bates, J.L.; Griffin, C.W.; Weber, W.J.

    1988-06-01

    The HfO/sub 2/-PrO/sub 1.83/-In/sub 2/O/sub 3/ system has been studied at the Pacific Northwest Laboratory to develop alternative, highly electrically conducting oxides as electrode and interconnection materials for solid oxide fuel cells. A coprecipitation process was developed for synthesizing single-phase, mixed oxide powders necessary to fabricate powders and dense oxides. A ternary phase diagram was developed, and the phases and structures were related to electrical transport properties. Two new phases, an orthorhombic PrInO/sub 3/ and a rhombohedral Hf/sub 2/In/sub 2/O/sub 7/ phase, were identified. The highest electronic conductivity is related to the presence of a bcc, In/sub 2/O/sub 3/ solid solution (ss) containing HfO/sub 2/ and PrO/sub 1.83/. Compositions containing more than 35 mol % of the In/sub 2/O/sub 3/ ss have electrical conductivities greater than 10/sup /minus/1/ (ohm-cm)/sup /minus/1/, and the two or three phase structures that contain this phase appear to exhibit mixed electronic-ionic conduction. The high electrical conductivities and structures similar to the Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/(HfO/sub 2/) electrolyte give these oxides potential for use as cathodes in solid oxide fuel cells. 21 refs.

  3. The competing oxide and sub-oxide formation in metal-oxide molecular beam epitaxy

    SciTech Connect (OSTI)

    Vogt, Patrick; Bierwagen, Oliver

    2015-02-23

    The hetero-epitaxial growth of the n-type semiconducting oxides β-Ga{sub 2}O{sub 3}, In{sub 2}O{sub 3}, and SnO{sub 2} on c- and r-plane sapphire was performed by plasma-assisted molecular beam epitaxy. The growth-rate and desorbing flux from the substrate were measured in-situ under various oxygen to metal ratios by laser reflectometry and quadrupole mass spectrometry, respectively. These measurements clarified the role of volatile sub-oxide formation (Ga{sub 2}O, In{sub 2}O, and SnO) during growth, the sub-oxide stoichiometry, and the efficiency of oxide formation for the three oxides. As a result, the formation of the sub-oxides decreased the growth-rate under metal-rich growth conditions and resulted in etching of the oxide film by supplying only metal flux. The flux ratio for the exclusive formation of the sub-oxide (e.g., the p-type semiconductor SnO) was determined, and the efficiency of oxide formation was found to be the highest for SnO{sub 2}, somewhat lower for In{sub 2}O{sub 3}, and the lowest for Ga{sub 2}O{sub 3}. Our findings can be generalized to further oxides that possess related sub-oxides.

  4. PLATES WITH OXIDE INSERTS

    DOE Patents [OSTI]

    West, J.M.; Schumar, J.F.

    1958-06-10

    Planar-type fuel assemblies for nuclear reactors are described, particularly those comprising fuel in the oxide form such as thoria and urania. The fuel assembly consists of a plurality of parallel spaced fuel plate mennbers having their longitudinal side edges attached to two parallel supporting side plates, thereby providing coolant flow channels between the opposite faces of adjacent fuel plates. The fuel plates are comprised of a plurality of longitudinally extending tubular sections connected by web portions, the tubular sections being filled with a plurality of pellets of the fuel material and the pellets being thermally bonded to the inside of the tubular section by lead.

  5. Electrolytic oxide reduction system

    SciTech Connect (OSTI)

    Wiedmeyer, Stanley G; Barnes, Laurel A; Williamson, Mark A; Willit, James L; Berger, John F

    2015-04-28

    An electrolytic oxide reduction system according to a non-limiting embodiment of the present invention may include a plurality of anode assemblies, a plurality of cathode assemblies, and a lift system configured to engage the anode and cathode assemblies. The cathode assemblies may be alternately arranged with the anode assemblies such that each cathode assembly is flanked by two anode assemblies. The lift system may be configured to selectively engage the anode and cathode assemblies so as to allow the simultaneous lifting of any combination of the anode and cathode assemblies (whether adjacent or non-adjacent).

  6. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOE Patents [OSTI]

    Dunning, John S.; Alman, David E.

    2002-11-05

    A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800 C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800 C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700 C. at a low cost

  7. Selective Oxidation of Organic Substrates to Partially Oxidized...

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

    Technology Brief (243 KB) Technology Marketing Summary Rapid and controlled rate of catalysis, utilizing ozone for oxidation of alcohols to ketones or aldehydes, is made possible...

  8. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOE Patents [OSTI]

    Dunning, John S.; Alman, David E.

    2002-11-05

    A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800.degree. C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800.degree. C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700.degree. C. at a low cost

  9. PREPARATION OF REFRACTORY OXIDE MICROSPHERE

    DOE Patents [OSTI]

    Haws, C.C. Jr.

    1963-09-24

    A method is described of preparing thorium oxide in the form of fused spherical particles about 1 to 2 microns in diameter. A combustible organic solution of thorium nitrate containing additive metal values is dispersed into a reflected, oxygen-fed flame at a temperature above the melting point of the resulting oxide. The metal additive is aluminum at a proportion such as to provide 1 to 10 weight per cent aluminum oxide in the product, silicon at the same proportion, or beryllium at a proportion of 12 to 25 weight per cent beryllium oxide in the product. A minor proportion of uranium values may also be provided in the solution. The metal additive lowers the oxide melting point and allows fusion and sphere formation in conventional equipment. The product particles are suitable for use in thorium oxide slurries for nuclear reactors. (AEC)

  10. Temperature dependence of structural parameters in oxide-ion-conducting Nd{sub 9.33}(SiO{sub 4}){sub 6}O{sub 2}: single crystal X-ray studies from 295 to 900K

    SciTech Connect (OSTI)

    Okudera, Hiroki . E-mail: h.okudera@fkf.mpg.de; Yoshiasa, Akira; Masubuchi, Yuuji; Higuchi, Mikio; Kikkawa, Shinichi

    2004-12-01

    Crystallographic space group, structural parameters and their thermal changes in oxide-ion-conducting Nd{sub 9.33}(SiO{sub 4}){sub 6}O{sub 2} were investigated using high-temperature single-crystal X-ray diffraction experiments in the temperature range of 295=oxide ions which belong to SiO{sub 4} tetrahedron indicated high rigidity of the tetrahedron in the structure, indicating that they form sp3 hybrid orbitals and the ligand oxygens do not take part in oxide-ion conductivity. Virtually full occupation of the 6h Nd site and highly anisotropic displacements of oxide ion inside the hexagonal channel were maintained over the temperature range examined. This result confirms that oxide-ion transport inside the hexagonal channel is the dominant process of conduction in the title compound.