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Office of Scientific and Technical Information
Ozone production at a rural site in Georgia during the summer 1992 SOS campaign
SciTech Connect
As part of the Southern Oxidant Study (SOS) (UCAR, 1990), Brookhaven National Laboratory operated a ``SENIOR`` (South Eastern Network for Intensive Ozone Research) measurement site on a campaign basis during parts of the summers of 1991 and 1992. Measurements were made for the purpose of understanding the pervasive high levels of O{sub 3} observed in the southeastern US (Meagher et al, 1987 Aneja et al, 1990; NRC, 1991). In this article the authors focus on the 1992 observations of O{sub 3} and the predication of O{sub 3} formation rates based on a radical budget calculation and based on the photostationary state.
Kleinman, L.I.; Lee, Yin-Nan; Springston, S.R. [and others
Study on Corrosion Behavior of Plasma Electrolytic Oxidation (PEO)
Science Conference Proceedings (OSTI)
Oxidation Studies of HVAS-sprayed Nanostructured Coatings at Elevated Temperature Ę Oxide Based Thermal Sprayed Coatings for Metal Dusting Applications.
Spectroscopic studies of metal growth on oxides
E-Print Network (OSTI)
Metal/oxide chemistry and metal cluster growth on oxides are fundamental to our understanding of the catalytic activity and selectivity of metal catalysts, thus considerable research recently has addressed the physical and chemical properties of metal clusters on well-defined oxide surfaces. In this work, the nucleation and growth modes of Ag on TiO?(110)(1x1) and (1x2) surfaces, Ag on ultra-thin Al?O? films, and Au on ultra-thin SiO? films were studied by scanning tunneling microscopy (STM), low energy ion scattering spectroscopy (LEIS) and X-ray photoelectron spectroscopy (XPS). In general, Ag grows three-dimensionally (3D) on both TiO?(110) and Al?O? film at 300 K. The growth mode of Au at fractional monolayer coverages is quasi-two dimensional (2D); at higher coverages, three-dimensional growth of Au was found. In these three systems, Ag/TiO?, Ag/Al?O?, and Au/SiO?, no strong chemical interaction was observed between metal clusters and substrates. Sintering was observed for all metal clusters upon annealing. A non-zero order desorption was observed for Ag/Al?O? and Au/SiO? in temperature programmed desorption (TPD) studies. The desorption activation energies decrease with decreasing metal coverages.
Luo, Kai
A Complete Characterization of the Gap between Convexity and SOS-Convexity
Our first contribution in this paper is to prove that three natural sum of squares (sos) based sufficient conditions for convexity of polynomials, via the definition of convexity, its first order characterization, and its ...
Ahmadi, Amir Ali
A Study of Catalytic Oxidation and Oxide Adsorption for the Removal of Tritium from Air
An apparatus and procedure were developed for studying the containment of tritium using catalytic conversion to the oxide followed by oxide adsorption. Data were obtained on the catalytic oxidation of elemental tritium and tritiated volatile hydrocarbons from pump oils between 23 and 538 degrees C. Oxidation efficiencies as high as 99.99997% (decontamination factor = 3.3 million) were obtained for total tritium levels of 1 ppm and a tritiated hydrocarbon level of approximately 0.2 ppb. In addition, a mathematical study was made to derive equations for the conceptual design of an "Emergency Containment System" for containment of tritium following an accidental release to room air.
Bixel, John C.; Kershner, Carl J.
Magnetism and spin transport studies on indium tin oxide
MAGNETISM AND SPIN TRANSPORT STUDIES ON INDIUM TIN OXIDE Ali Moraad Hakimi Darwin College University of Cambridge A dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge February 2011 In loving memory of my... Grandfathers, Cyrus and Peter Abstract This dissertation reports on a detailed systematic study of the investigation into using Indium Oxide based materials in next generation spin-transport electronic ap- plications. Initial studies focused on the optimisation...
Hakimi, Ali Moraad Heydar
5-kW Solid Oxide Fuel Cell Case Study
This report chronicles, as a case study, a project in which an Acumentrics 5-kW solid oxide fuel cell was installed at Cuyahoga Valley National Park in Ohio.
Energy Based Methods in Wind Turbine Control CeSOS Highlights and AMOS Visions
Energy Based Methods in Wind Turbine Control CeSOS Highlights and AMOS Visions Morten D. Pedersen 1 / 26 #12;This talk 1 Background 2 Understanding the Wind Turbine 3 Nonlinear Turbine Modeling 4;Background The Problem Previously stable wind turbine systems began exhibiting resonant behavior when put
N├Ėrv├źg, Kjetil
SRF Materials: Fundamental studies of interfacial oxidation chemistry of niobium
NLE Websites -- All DOE Office Websites (Extended Search)
ANL/FNAL/UC Collaboration meeting 27 Nov 2007 ANL/FNAL/UC Collaboration meeting 27 Nov 2007 SRF Materials: Fundamental studies of interfacial oxidation chemistry of niobium Lance Cooley - FNAL Mike Pellin, Jim Norem - ANL Steve Sibener - UC John Zasadzinski, Thomas Prolier - IIT f ANL/FNAL/UC Collaboration meeting 27 Nov 2007 May 2007 SRF Materials Workshop @ FNAL energized 2 collaborations being reported here * Atomic layer deposition of conformal coatings onto cavities (Pellin, Zasadzinski, Prolier, Norem, Antoine/Wu/Cooley) - Directly probe surface superconductivity (SC) via 1.5 K STM + XPS surface composition - Nb oxidation layer proximity effects! - ALD Al 2 O 3 coated cavity first, for oxidation control; multilayer- coated cavity later - A new philosophy: build up, not etch down - First annealing results reveal oxidation vs
P-64: A Comparative Study of Metal Oxide Coated Indium-tin Oxide Anodes
Indium-tin oxide anodes capped with certain oxides of metals enhance while other oxides degrade the hole-injection and quantum efficiencies of organic light-emitting diodes (OLEDs). The oxides of tin, zinc, praseodymium, yttrium, gallium, terbium and titanium have been investigated. The power efficiency of an OLED with a 1nm thick praseodymium oxide cap is improved by 2.5 times over that of a conventional OLED without an oxide capped anode.
For Organic Light-Emitting; Chengfeng Qiu; Haiying Chen; Zhilang Xie; Man Wong; Hoi Sing Kwok
Model catalytic oxidation studies using supported monometallic and heterobimetallic oxides. Progress report, August 1, 1991--January 31, 1992
DOE Green Energy (OSTI)
This research program is directed toward a more fundamental understanding of the effects of catalyst composition and structure on the catalytic properties of metal oxides. Metal oxide catalysts play an important role in many reactions bearing on the chemical aspects of energy processes. Metal oxides are the catalysts for water-gas shift reactions, methanol and higher alcohol synthesis, isosynthesis, selective catalytic reduction of nitric oxides, and oxidation of hydrocarbons. A key limitation to developing insight into how oxides function in catalytic reactions is in not having precise information of the surface composition under reaction conditions. To address this problem we have prepared oxide systems that can be used to study cation-cation effects and the role of bridging (-O-) and/or terminal (=O) surface oxygen anion ligands in a systematic fashion. Since many oxide catalyst systems involve mixtures of oxides, we selected a model system that would permit us to examine the role of each cation separately and in pairwise combinations. Organometallic molybdenum and tungsten complexes were proposed for use, to prepare model systems consisting of isolated monomeric cations, isolated monometallic dimers and isolated bimetallic dimers supported on silica and alumina. The monometallic and bimetallic dimers were to be used as models of more complex mixed- oxide catalysts. Our current program was to develop the systems and use them in model oxidation reactions.
Ekerdt, J.G.
Study of lithium diffusion in RF sputtered Nickel/Vanadium mixed oxides thin films
Study of lithium diffusion in RF sputtered NickelÁ/Vanadium mixed oxides thin films F. Artuso a lithium insertion inside RF sputtered Ni/V mixed oxides thin films have been investigated employing, showed three steps clearly involved in the intercalation mechanism of lithium in the oxide films: (i
Artuso, Florinda
An experimental study of isobutane oxidation at transition temperatures
The oxidation of isobutane at temperatures in the range 563-693 K has been studied experimentally using a static reactor. Gas chromatographic analysis was used to measure stable species concentrations. The experimental results were used to postulate the main reaction paths of the mechanism at these temperatures. A region of negative temperature coefficient (NTC) was observed between 650 and 680 K. Changes in the product yields and product distribution indicated a transition in the mechanism across the NTC region, from low to intermediate temperatures. Analysis of the experimental results and comparison with results for other fuels, such as n-butane, propane and propene, indicated that the NTC and mechanism transition were strongly dependent on the shift in the equilibrium of CH/sub 3/ + O/sub 2/ <==> CH/sub 3/O/sub 2/. The results are also discussed in relation in relation to recent engine results.
Wilk, R.D.; Cernansky, N.P.; Miller, D.L.
Oxidation Studies of HVAS-sprayed Nanostructured Coatings at ...
In the present investigation, HVAS process has been used to deposit coating on steel substrates.The oxidation behavior of HVAS sprayed (FeCr)-basedĀ...
Density Functional Theory Study of Copper Oxide as Low-cost ...
Density Functional Theory Study of Copper Oxide as Low-cost Photovoltaic Material Ę Dye-sensitized Solar Cells with Anodized Aluminum Alloy-based Counter-Ā...
Oxidation of stepped Pt(111) studied by x-ray photoelectron spectroscopy and density functional theory
In this comparative density functional theory and x-ray photoelectron spectroscopy study on the interaction of oxygen with stepped Pt(111) surfaces, we show that both the initial adsorption and oxidation occur at the steps rather than terraces. An equivalent behavior was observed for the oxide formation at higher chemical potentials, where, after the formation of a one-dimensional PtO{sub 2}-type oxide at the steps, similar oxide chains form on the (111) terraces, indicating the initial stages of bulk oxide formation.
Bandlow, Jochen; Kaghazchi, Payam; Jacob, Timo [Institut fuer Elektrochemie, Universitaet Ulm, Albert-Einstein-Allee 47, D-89069 Ulm (Germany); Papp, C.; Traenkenschuh, B.; Streber, R.; Lorenz, M. P. A.; Fuhrmann, T.; Steinrueck, H.-P. [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, D-91058 Erlangen (Germany); Denecke, R. [Wilhelm-Ostwald-Institut fuer Physikalische und Theoretische Chemie, Universitaet Leipzig, Linnestr. 2, D-04103 Leipzig (Germany)
Soft X-ray Spectroscopy Study of the Electronic Structure of Oxidized and Partially Oxidized Magnetite Nanoparticles
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 conduction band of TiO2.
Gilbert, Benjamin; Katz, Jordan E.; Denlinger, Jonathan D.; Yin, Yadong; Falcone, Roger; Waychunas, Glenn A.
Theoretical kinetic study of the low temperature oxidation of ethanol
In order to improve the understanding of the low temperature combustion of ethanol, high-level ab initio calculations were performed for elementary reactions involving hydroxyethylperoxy radicals. These radicals come from the addition of hydroxethyl radicals (?CH3CHOH and ?CH2CH2OH) on oxygen molecule. Unimolecular reactions involving hydroxyethylperoxy radicals and their radical products were studied at the CBS-QB3 level of theory. The results allowed to highlight the principal ways of decomposition of these radicals. Calculations of potential energy surfaces showed that the principal channels lead to the formation of HO2 radicals which can be considered, at low temperature, as slightly reactive. However, in the case of CH3CH(OOH)O? radicals, a route of decomposition yields H atom and formic peracid, which is a branching agent that can strongly enhance the reactivity of ethanol in low temperature oxidation. In addition to these analyses, high-pressure limit rate constants were derived in the temperature rang...
Fournet, Renķ; Bounaceur, Roda; MoliĶre, Michel
Structural Studies of Nitric Oxide Synthase Inhibitor Complexes...
from artery and vein is nitric oxide. Proc. Natl. Acad. Sci. USA 84, 9265-9269 (1987). Khan, M.T. & Furchgott, R. Additional evidence that endothelium-derived relaxing factor is...
Development studies for a novel wet oxidation process
A catalytic wet oxidation process (DETOX), which uses an acidic iron solution to oxidize organic compounds to carbon dioxide, water, and other simple products, was investigated as a potential method for the treatment of multicomponent hazardous and mixed wastes. The organic compounds picric acid, poly(vinyl chloride), tetrachlorothiophene, pentachloropyridine, Aroclor 1260 (a polychlorinated biphenyl), and hexachlorobenzene were oxidized in 125 ml reaction vessels. The metals arsenic, barium, beryllium, cadmium, cerium (as a surrogate for plutonium), chromium, lead, mercury, neodymium (as a surrogate for uranium), nickel, and vanadium were tested in the DETOX solution. Barium, beryllium, cerium, chromium, mercury, neodymium, nickel, and vanadium were all found to be very soluble (>100 g/l) in the DETOX chloride-based solution. Arsenic, barium, cadmium, and lead solubilities were lower. Lead could be selectively precipitated from the DETOX solution. Chromium(VI) was reduced to relatively non-toxic chromium(III) by the solution. Six soils were contaminated with arsenic, barium, beryllium, chromium, lead, and neodymium oxides at approximately 0.1% by weight, and benzene, trichloroethene, mineral oil, and Aroclor 1260 at approximately 5% by weight total, and 5.g amounts treated with the DETOX solution in unstirred 125. ml reaction bombs. It is felt that soil treatment in a properly designed system is entirely possible despite incomplete oxidation of the less volatile organic materials in these unstirred tests.
Dhooge, P.M.; Hakim, L.B.
Further studies of the effects of oxidation on the surface properties of coal and coal pyrite
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.
Herrera, M.N.
A kinetics study of the atmospheric pressure CVD reaction of silane and nitrous oxide
A mechanistic study of oxide deposition from silane and nitrous oxide between 495{sup 0}C and 690{sup 0}C was performed in a laminar flow, cool wall reactor. Results indicate the existence of two distinct chemical pathways. At high nitrous oxide concentrations, the deposition reaction is dominated by radical chain chemistry initiated by the decomposition of N/sub 2/O. At lower N/sub 2/O concentrations, the decomposition of silane to form silylene (SiH/sub 2/) initiates the deposition. Studies of the reaction of disilane and nitrous oxide confirmed the role of SiH/sub 2/ in the deposition. Reactions involving SiH/sub 2/ are used to explain the observed growth of sub-stoichiometric oxides under low N/sub 2/O conditions.
Chapple-Sokol, J.D.; Giunta, C.J.; Gordon, R.G. (Harvard Univ., Cambridge, MA (USA). Dept. of Chemistry)
A Reactive Oxide Overlayer on Rh Nanoparticles during CO Oxidation and Its Size Dependence Studied by in Situ Ambient Pressure XPS
CO oxidation is one of the most studied heterogeneous reactions, being scientifically and industrially important, particularly for removal of CO from exhaust streams and preferential oxidation for hydrogen purification in fuel cell applications. The precious metals Ru, Rh, Pd, Pt, and Au are most commonly used for this reaction because of their high activity and stability. Despite the wealth of experimental and theoretical data, it remains unclear what is the active surface for CO oxidation under catalytic conditions for these metals. In this communication, we utilize in situ synchrotron ambient pressure X-ray photoelectron spectroscopy (APXPS) to monitor the oxidation state at the surface of Rh nanoparticles during CO oxidation and demonstrate that the active catalyst is a surface oxide, the formation of which is dependent on particle size. The amount of oxide formed and the reaction rate both increase with decreasing particle size.
Grass, Michael E.; Zhang, Yawen; Butcher, Derek R.; Park, Jeong Y.; Li, Yimin; Bluhm, Hendrik; Bratlie, Kaitlin M.; Zhang, Tianfu; Somorjai, Gabor A.
A Study on Carbon-Nanotube Local Oxidation Lithography Using an Atomic Force Microscope
In this paper, nanoscale anodic oxidation lithography using an atomic force microscope (AFM) is systematically studied on carbon nanotubes (CNTs). Trends between the produced feature size and the corresponding process parameters, such as applied voltage, ...
K. Kumar; O. Sul; S. Strauf; D. S. Choi; F. Fisher; M. G. Prasad; E. Yang
Design and construction of rigs for studying surface condensation and creating anodized metal oxide surfaces
This thesis details the design and construction of a rig for studying surface condensation and a rig for creating anodized metal oxides (AMOs). The condensation rig characterizes condensation for different surfaces; this ...
Sun, Wei-Yang
FNAL/UC Collaboration meeting 27 Nov 2007 FNAL/UC Collaboration meeting 27 Nov 2007 SRF Materials: Niobium Oxidation, Control A New Explanation for Baking! Pellin 1 , Zasadzinski 2 , Prolier 1,2 , Moore 3 , Norem 3 , Cooley 4 1. Materials Science Division, ANL 2. Department of Biological, Chemical and Physical Sciences, IIT 3. High Energy Physics, ANL 4. Technical Division, FNAL ANL-LDRD ANL/FNAL/UC Collaboration meeting 27 Nov 2007 XPS a Surface Probe of Nb Oxidation Nb 2 O 5 Nb NbO x Dielectric Nb 2 O 5 Nb 2 O 5-╬┤ , NbO 2-╬┤ are magnetic NbO x (0.2 < x < 2),metallic NbO x precipitates (0.02 < x < 0.2) Scattering off magnetic interfaces or precipitates gives rise to Shiba states inside the gap. These cause dissipation (lowering Q). Nb samples supplied by FNAL! ANL/FNAL/UC Collaboration meeting 27 Nov 2007 Point Contact Tunneling -
Transpiring wall supercritical water oxidation reactor salt deposition studies
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.
Haroldsen, B.L.; Mills, B.E.; Ariizumi, D.Y.; Brown, B.G. [and others
A STUDY OF COPPER OXIDATION AND SOME IRRADIATION EFFECTS. Final Report
A new volumetric apparatus and a procedure for the study of the kinetics of oxidation of metals in a nuclear reactor are described. Measurements were made on the initial stages of oxidation of 99.999% pure, polycrystalline Cu wires at 100 to 300 c- C. The O gas was held at constant pressures during each isothermal oxidation. The pressures employed ranged from 50 to 200 mm Hg. A significant increase in logarithmic oxidation rate was observed in the presence of 2 x 10/sup 6/ r/hr of gamma irradiation in the temperature range 100 to 250 c- C. The experimental data were interpreted to be in support of the discontinuous oxidation theory of Benard. Sharp transitions were observed in the kinetic rate laws. In general, a logarithmic rate region was observed that was both preceded and followed by regions of parabolic rate behavior. No cubic rate behavior was observed. The effect of temperature on the parabolic rate constants was found to obey the Arrhenius equation. The activation energy was found to be from 0.73 to 0.82 ev, and the logarithmic rate constants were found to be independent of temperature. The effect of pressure was observed to be marked in the early part of the oxidation. Increased pressure of O decreases the transition time and thickness where the change from parabolic to logarithmic rate behavior occurs. (auth)
Tobin, J M
Formic acid oxidation in a polymer electrolyte fuel cell: A real-time mass-spectrometry study
The electro-oxidation of formic acid was studied in a direct-oxidation polymer-electrolyte fuel cell at 170 C using real-time mass spectrometry. The results are compared with those obtained for methanol oxidation under the same conditions. Formic acid was electrochemically more active than methanol on both Pt-black and Pt-Ru catalysts. The polarization potential of formic acid oxidation was ca. 90 to 100 mV lower than that of methanol. The oxidation of formic acid was dependent on the water/formic acid mole ratio. The best anode performance was obtained using a water/formic acid mole ratio of {approximately}2. In addition, Pt/Ru catalyst was more active than Pt-black for formic acid oxidation. The mass spectrometric results showed that CO{sub 2} is the only reaction product of formic acid oxidation. The results are discussed in terms of possible formic acid oxidation mechanisms.
Weber, M.; Wang, J.T.; Wasmus, S.; Savinell, R.F. [Case Western Reserve Univ., Cleveland, OH (United States)
Parameter Study of Transport Processes with Catalytic Reactions in Intermediate Temperature Solid Oxide Fuel Cells
Solid oxide fuel cell is one of most promising types of fuel cells with advantages of high efficiencies, flexibility of usable fuel types. The performance of SOFC is strongly affected by cell overall parameters, e.g., temperature, pressure, reaction ... Keywords: parameter study, SOFC model, 3D CFD approach, refoming reactions
Chao Yang; Guogang Yang; Danting Yue; Jinliang Yuan
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.
Frederick S. Pettit; Gerald H. Meier
X-Ray Absorption Studies of Vanadium-Containing Metal Oxide Nanocrystals
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 methanol oxidation were used to probe the chemical differences between sol-gel prepared and conventionally prepared metal oxides. Both V/MgO and V/SiO2 were studied. For both catalysts, similar product selectivities were noted for either preparation method, suggesting similar acid/base and redox properties for the catalysts. At lower weight loadings (butane oxidation to maleic anhydride. In this method vanadium (V) triisopropoxide was reacted with orthophosphoric acid in THF to form a gel. Drying this gel under air resulted in an intercalated VOPO4 compound, where solvent molecules were trapped between layers of the vanadium phosphate compound. Higher surface areas could be achieved by drying this gel at high pressure in an autoclave. The amount of solvent (THF) placed in the autoclave was important in this process. Low amounts of solvent led to a lower surface area, as the solvent evaporated before reaching the critical point and collapsed the gel's pores. In addition, vanadium reduction occurred in the autoclave due to reaction of isopropanol with the vanadium phosphate. Higher amounts of THF reduced the concentration of isopropanol, leading to less reduction. Surfaces areas in excess of 100 m2/g were achieved with this method, and the product was confirmed through XPS and IR to be VOHPO4*0.5H2O, the common precursor for industrial VPO catalysts. Furthermore, this product displayed a platelet morphology, which is desirable for butane oxidation. Further work showed that this material could be transformed to (VO)2P2O7 (the industrial catalyst for butane oxidation to maleic anhydride) by heating under nitrogen without losing much surface are
Hohn, Keith, L.
Fundamental Studies of the Durability of Materials for Interconnects in Solid Oxide Fuel Cells
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 the area-specific resistance (ASR) to estimate the electrical degradation of the interconnect. In addition to the baseline study of pure nickel, steps were taken to decrease the ASR through alloying and surface modifications. Finally, high conductivity composite systems, consisting of nickel and silver, were studied. These systems utilize high conductivity silver pathways through nickel while maintaining the mechanical stability that a nickel matrix provides.
Electrochemical Behavior and Li Diffusion Study of LiCoO? Thin Film Electrodes Prepared by PLD
Preferred c-axis oriented LiCoO? thin films were prepared on the SiO?/Si (SOS) substrates by pulsed laser deposition (PLD). Thin film electrodes without carbon and binder are ideal samples to study the electrochemical ...
Xia, H.
Transient FTIR studies of the reaction pathway for n-butane selective oxidation over vanadyl pyrophosphate
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.
Xue, Z.Y.; Schrader, G.L. [Ames Lab., IA (United States)] [Ames Lab., IA (United States); [Iowa State Univ., Ames, IA (United States). Dept. of Chemical Engineering
Atomic scale studies of interface formation between oxides and III-V semiconductor surfaces
volatile [151], but indium oxides are not [156]; therefore,with them having an indium oxide composition. Bulk In 2 O 3temperatures and the indium oxides remain in the form of
Clemens, Jonathon Boyd
Dissolution and electrochemical impedance spectroscopy studies of thin copper oxide films on copper in semi-aqueous fluoride solutions
The selective dissolution of thin copper oxide films grown on copper in semi-aqueous formulations containing dimethyl sulfoxide (DMSO), ammonium fluoride (NH"4F) and water was studied. Optimization of the formulations was carried out by systematic evaluation ... Keywords: BEOL cleaning, Copper oxide removal, Electrochemical impedance spectroscopy, SAF chemical system
N. Venkataraman; S. Raghavan
[Fundamental studies in oxidation-reduction in relation to water photolysis]. Progress report, June 26, 1989--November 1, 1990
Objective is to solve problems in photoredox catalysis pertinent to developing membrane-base photoconversion/photostorage systems. The research is divided into: Physical studies (light scattering) on viologen-doped vesicles, transmembrane oxidation-reduction mechanisms, interfacial charge recombination, water oxidation catalysts.
Hurst, J.K.
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 methanol oxidation were used to probe the chemical differences between sol-gel prepared and conventionally prepared metal oxides. Both V/MgO and V/SiO2 were studied. For both catalysts, similar product selectivities were noted for either preparation method, suggesting similar acid/base and redox properties for the catalysts. At lower weight loadings (<5%), activity was also similar, but at higher weight loadings the sol-gel prepared catalysts were more active. This was attributed to the greater dispersion of vanadium on sol-gel prepared catalysts, and it was suggested that small vanadium oxide domains were more active in methanol oxidation than polymeric and bulk domains. A novel sol-gel method was developed for preparation of VPO catalysts, which are used industrially in butane oxidation to maleic anhydride. In this method vanadium (V) triisopropoxide was reacted with orthophosphoric acid in THF to form a gel. Drying this gel under air resulted in an intercalated VOPO4 compound, where solvent molecules were trapped between layers of the vanadium phosphate compound. Higher surface areas could be achieved by drying this gel at high pressure in an autoclave. The amount of solvent (THF) placed in the autoclave was important in this process. Low amounts of solvent led to a lower surface area, as the solvent evaporated before reaching the critical point and collapsed the gel's pores. In addition, vanadium reduction occurred in the autoclave due to reaction of isopropanol with the vanadium phosphate. Higher amounts of THF reduced the concentration of isopropanol, leading to less reduction. Surfaces areas in excess of 100 m2/g were achieved with this method, and the product was confirmed through XPS and IR to be VOHPO4*0.5H2O, the common precursor for industrial VPO catalysts. Furthermore, this product displayed a platelet morphology, which is desirable for butane oxidation. Further work showed that this material could be transformed to (VO)2P2O7 (the industrial catalyst for butane oxidation to maleic anhydride) by heating under nitrogen without losing much surface are
Electrochemical impedance spectroscopy studies of lithium diffusion in doped manganese oxide
Cathode performance is critical to lithium ion rechargeable battery performance; effects of doping lithium manganese oxide cathode materials on cathode performance are being investigated. In this paper, Li diffusion in Al-doped LiMn{sub 2}O{sub 4} was studied and found to be controlled by the quantity of Al dopant. Electrochemical cycling was conducted at 0.5mA/cm{sub 2}; electrochemical impedance spectra were taken at open circuit potential, with impedance being measured at 65 kHz-0.01 Hz. As the Al dopant level was increased, the Li diffusion rate decreased; this was attributed to the decreased lattice parameter of the doped oxide.
Johnson, B.J.; Doughty, D.H.; Voigt, J.A.; Boyle, T.J.
Experimental study of the oxidation of methyl oleate in a jet-stirred reactor
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)
Bax, Sarah; Hakka, Mohammed Hichem; Glaude, Pierre-Alexandre; Herbinet, Olivier; Battin-Leclerc, Frederique [Laboratoire Reactions et Genie des Procedes, Nancy Universite, CNRS, ENSIC, BP 20451, 1 rue Grandville, 54001 Nancy (France)
Bench Scale Study of Integrated Chemical Oxidation and Enhanced Bio-Stabilization of Manufactured Gas Plant SoilsBench Scale Study of Integrated Chemical Oxidation and Enhanced Bio-Stabilization of Manufactured Gas Plant Soils
A bench-scale study was conducted to investigate a new remedial approach to treat constituents of concern (COC) that were present in soil from a former manufactured gas plant (MGP) site. The approach combines in situ chemical oxidation, in situ stabilization, and enhanced biodegradation to provide overall degradation/stabilization of COCs that would not be possible using any of the three technologies alone. Sodium persulfate was chosen as the oxidant because it can be activated by ...
F3, A Comparative Study of Thermal and Deposited Gate Oxides on ...
Thermal oxidation processes consisted of dry oxidation at 1175░C followed by an .... Microstructure and Properties of Colloidal ITO Films and Cold-Sputtered ITO Films .... Graphene Produced from Ion Implanted Semi-Insulating Silicon Carbide.
A procedure is described for studying carbon dioxide uptake in algae using C/sup 14/-labeled sodium bicarbonate as the source of carbon dioxide, Actively dividing, water grown and deuterium oxide adapted, Scenedesmus obliquus and Chlorella vulgaris were employed in the studies. Uptake comparisons were made over pH range 6 to 9 using appropriate buffer systems. Uptake was fairly constant in the range pH 6 to 8 for both the aqueous and deuterated algae. Above pH 8 uptake dropped markedly. In general, the deuterated algae showed between 1O and 30% lower uptake than ordinary algae. Greater chlorophyll content is associated with higher carbon dioxide uptake. (auth)
Blake, M.I.; Kaganove, A.S.; Katz, J.J.
Catechol oxidation by peroxidase-positive astrocytes in primary culture: an electron spin resonance study
In rodents, chronic estrogenization has been shown to induce degeneration of dendrites and myelin figures in the hypothalamic arcuate nucleus adjacent to peroxidase-positive astrocyte processes. Because in this brain region estradiol is metabolized to 2-hydroxyestradiol (catecholestrogen), we hypothesized that the latter may be oxidized by the astrocytic peroxidase activity to cytotoxic ortho-semiquinones as occurs in peripheral tissues. Cysteamine induces nonenzymatic peroxidase activity in cultured astroglia identical to that observed in viva. Using electron spin resonance, we demonstrate robust peroxidase-catalyzed oxidation of 2-hydroxyestradiol and dopamine by cysteaminepretreated astrocyte cultures relative to untreated controls. These results implicate the peroxidase-positive astrocytes in the pathogenesis of estradiol-related hypothalamic damage, parkinsonism, and other free-radical-related neurologic disorders. A distinct subpopulation of granule-laden astrocytes exhibiting an affinity for chrome alum hematoxylin and aldehyde fuchsin (Gomori stains) has been described in the periventricular brain of many vertebrates, including humans. Their cytoplasmic inclusions are rich in sulfhydryl groups, emit an orange-red autofluorescence, and stain intensely with diaminobenzidine (DAB), a marker ofendogenous peroxidase activity (Diepen et al., 1954; Creswell et al., 1964; Srebro, 197 1; Goldgefter, 1976; Schipper et al., 1988). Histochemical studies have implicated porphyrins and metalloporphyrins (heme) as the source of the autofluorescence and nonenzymatic peroxidase activity in these cells, respectively
Yashige Kotake; Edward G. Janzen
Catalytic partial oxidation of iso-octane over rhodium catalysts: An experimental, modeling, and simulation study
Catalytic partial oxidation of iso-octane over a rhodium/alumina coated honeycomb monolith is experimentally and numerically studied at short-contact times for varying fuel-to-oxygen ratios. A new experimental set-up with well-defined inlet and boundary conditions is presented. The conversion on the catalyst and in the gas-phase is modeled by detailed reaction mechanisms including 857 gas-phase and 17 adsorbed species. Elementary-step based heterogeneous and homogeneous reaction mechanisms are implemented into two-dimensional flow field description of a single monolith channel. Experiment and simulation provide new insights into the complex reaction network leading to varying product distribution as function of fuel-to-oxygen ratio. At fuel rich conditions, the formation of by-products that can serve as coke precursors is observed and interpreted. (author)
Hartmann, M.; Minh, H.D. [Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Maier, L. [Institute for Nuclear and Energy Technology, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Deutschmann, O. [Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Institute for Nuclear and Energy Technology, Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany)
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-value, dirty feed materials. The Phase I results indicate that a practical means to overcome limitations on biomass slurry feed concentration and preheat temperatuare is to coprocess an auxiliary high heating value material. SWPO coprocessing of tow hgih-water content wastes, partially dewatered sewage sludge and trap grease, yields a scenario for the production of hydrogen at highly competitive prices. It is estimated that there are hundreds if not thousands of potential sites for this technology across the US and worldwide.
Experimental studies and thermodynamic modelling of volatilities of uranium, plutonium, and americium from their oxides and from their oxides interacted with ash
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.
Krikorian, O.H.; Ebbinghaus, B.B.; Adamson, M.G.; Fontes, A.S. Jr.; Fleming, D.L.
Chemical kinetic study of the oxidation of toluene and related cyclic compounds
Chemical kinetic models of hydrocarbons found in transportation fuels are needed to simulate combustion in engines and to improve engine performance. The study of the combustion of practical fuels, however, has to deal with their complex compositions, which generally involve hundreds of compounds. To provide a simplified approach for practical fuels, surrogate fuels including few relevant components are used instead of including all components. Among those components, toluene, the simplest of the alkyl benzenes, is one of the most prevalent aromatic compounds in gasoline in the U.S. (up to 30%) and is a promising candidate for formulating gasoline surrogates. Unfortunately, even though the combustion of aromatics been studied for a long time, the oxidation processes relevant to this class of compounds are still matter of discussion. In this work, the combustion of toluene is systematically approached through the analysis of the kinetics of some important intermediates contained in its kinetic submechanism. After discussing the combustion chemistry of cyclopentadiene, benzene, phenol and, finally, of toluene, the model is validated against literature experimental data over a wide range of operating conditions.
Mehl, M; Frassoldati, A; Fietzek, R; Faravelli, T; Pitz, W; Ranzi, E
HRTEM image simulations for the study of ultra-thin gate oxides
We have performed high resolution transmission electron microscope (HRTEM) image simulations to qualitatively assess the visibility of various structural defects in ultra-thin gate oxides of MOSFET devices, and to quantitatively examine the accuracy of HRTEM in performing gate oxide metrology. Structural models contained crystalline defects embedded in an amorphous 16 {angstrom}-thick gate oxide. Simulated images were calculated for structures viewed in cross-section. Defect visibility was assessed as a function of specimen thickness and defect morphology, composition, size and orientation. Defect morphologies included asperities lying on the substrate surface, as well as ''bridging'' defects connecting the substrate to the gate electrode. Measurements of gate oxide thickness extracted from simulated images were compared to actual dimensions in the model structure to assess TEM accuracy for metrology. The effects of specimen tilt, specimen thickness, objective lens defocus and coefficient of spherical aberration (C{sub s}) on measurement accuracy were explored for nominal 10{angstrom} gate oxide thickness. Results from this work suggest that accurate metrology of ultra-thin gate oxides (i.e. limited to several per cent error) is feasible on a consistent basis only by using a C{sub s}-corrected microscope. However, fundamental limitations remain for characterizing defects in gate oxides using HRTEM, even with the new generation of C{sub s}-corrected microscopes.
Taylor, Seth T.; Mardinly, John; O'Keefe, Michael A.
Evaluation of Alternatives for Safer and More Efficient Reactions: A study of the N-oxidation of Alkylpyridines
The catalytic N-oxidation of alkylpyridines, a reaction which uses hydrogen peroxide as the oxidizing agent and the water soluble phosphotungstic acid as the catalyst, is a reaction employed in the pharmaceutical industry. The safety concerns of this process revolve around the decomposition of hydrogen peroxide and the liquid-liquid phase separation of the reacting mixture. The decomposition of hydrogen peroxide is an undesired reaction parallel to the desired N-oxidation and is responsible for: 1) a high potential for runaway due to the condition sensitivity of the peroxide group, 2) a potential over-pressurization of the reaction vessel during a runaway due to the production of oxygen, and 3) the enrichment with oxygen of the flammable alkylpyridine environment. The presence of an organic phase and an aqueous phase occurs in a wide range of conditions and results in: 1) a dramatic reduction in the reaction selectivity, and consequently in the efficiency, due to the additional mass transfer constrains imposed by the phase separation, and 2) the safety of the process being seriously compromised because most of the catalyst remains in the aqueous phase, excessively promoting the decomposition of hydrogen peroxide over the N-oxidation. With these concerns in mind, this research aimed to determine conditions for an inherently safer and more efficient N-oxidation reaction and focused on three key targets: i) the possibility of reducing the extend of the decomposition of hydrogen peroxide, thus leading to an inherently safer process, ii) the study of phase equilibrium so as to enable the identification of conditions that increase the efficiency of the N-oxidation and reduces the hazards, and iii) the evaluation of safety parameters that will allow for the control of a potential runaway reaction. Two alkylpyridines were considered: 2-methylpyridine which represents the case of a homogeneous reacting mixture and 2,6-dimethylpyridine to study the two-liquid phase separation effects. The methodology employed calorimetric studies to assess the runaway behavior and to determine the conditions that favor the N-oxidation, and for the N-oxidation of 2,6-dimethylpyridine, thermodynamic studies were incorporated to evaluate the conditions for phase separation.
Saenz Noval, Lina Rocio
Degradation of Guar-Based Fracturing Gels: A Study of Oxidative and Enzymatic Breakers
Unbroken gel and residue from guar-based fracturing gels can be a cause for formation damage. The effectiveness of a fracturing treatment depends on better achieveing desired fracture geometry, proper proppant placement and after that, a good clean-up. The clean-up is achieved by reducing the fluid viscosity using chemical additives called "Breakers". There are many different types of breakers used in the industry, but they can be broadly divided into two categories: oxidizers and enzymes. Breaker perfromance depends on bottomhole temperature, breaker concentration and polymer loading. Different kind of breakers, used at different concentrations and temperatures, give different kind of "break" results. Therefore, the amount of unbroken gel and residue generated is also different. This project was aimed at studying basic guar-breaker interactions using some of the most common breakers used in the industry. The breakers studied cover a working temperature range of 75 degrees F to 300 degrees F. The effectiveness of each breaker was studied and also the amount of damage that it causes. Viscosity profiles were developed for various field concentrations of breakers. The concentrations were tested over temperature ranges corresponding to the temperatures at which each breaker is used in the field. The majority of these viscosity tests were 6 hours long, with a few exceptions. Early time viscosity data, for the intial 10 minutes of the test, was also plotted from these tests for fracturing applications where the breaker is required to degrade the fluid by the time it reached downhole. This was needed to prevent the damage to the pumping equipment at the surface yet still have almost water-like fluid entering into the formation. The study provides a better understanding of different breaker systems, which can be used in the industry, while designing fracturing fluid systems in order to optimize the breaker performance and achieve a better, cleaner break to minimize the formation damage caused by polymer degradation.
Sarwar, Muhammad Usman
An experimental study of the autoignition characteristics of conventional jet fuel/oxidizer mixtures: Jet-A and JP-8
Ignition delay times of Jet-A/oxidizer and JP-8/oxidizer mixtures are measured using a heated rapid compression machine at compressed charge pressures corresponding to 7, 15, and 30 bar, compressed temperatures ranging from 650 to 1100 K, and equivalence ratios varying from 0.42 to 2.26. When using air as the oxidant, two oxidizer-to-fuel mass ratios of 13 and 19 are investigated. To achieve higher compressed temperatures for fuel lean mixtures (equivalence ratio of {proportional_to}0.42), argon dilution is also used and the corresponding oxidizer-to-fuel mass ratio is 84.9. For the conditions studied, experimental results show two-stage ignition characteristics for both Jet-A and JP-8. Variations of both the first-stage and overall ignition delays with compressed temperature, compressed pressure, and equivalence ratio are reported and correlated. It is noted that the negative temperature coefficient phenomenon becomes more prominent at relatively lower pressures. Furthermore, the first-stage-ignition delay is found to be less sensitive to changes in equivalence ratio and primarily dependent on temperature. (author)
Kumar, Kamal; Sung, Chih-Jen [Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States)
A study on oxidized glassy carbon sheets for bipolar supercapacitor electrodes
Electrochemical Double Layer Capacitors (EDLC) for high energy and power density applications, based on glassy carbon (GC) electrodes, are being developed in this laboratory. In the context of this project, GC sheets were oxidized and investigated with Small Angle X-ray Scattering (SAXS), Electrochemical Impedance Spectroscopy (EIS) and Nitrogen Gas Adsorption (BET). During oxidation on active film with open pores is built on the surface of the GC. Upon oxidation, the internal volumetric surface area of the active film decreases, whereas the volumetric electrochemical double layer capacitance increases. The authors show that this effect is correlated with the opening, the growth and the coalescence of the pores.
Braun, A.; Baertsch, M.; Geiger, F. [and others
... Department of Veterans Affairs. Environmental Protection Agency. ... National Security Council. ... Nuclear Regulatory Commission. US Access Board. ...
Study of Metal-oxide Composites Prepared by Ball Milling and ...
Aerosol Route Synthesis of Copper Oxide Nanoparticles Using Copper Nitrate Solution Ę AlGaAs-Based Optical ... Defect Energetics and Fission Product Transport in ZrC ... Enhancing Mineral Beneficiation by High Intensity Power Ultrasound.
A Study of the Selective Surface and Internal Oxidation of Advanced ...
... austenitic states were constructed and interestingly predict external oxidation should ... Chemistry on Corrosion of Hot Section Components of Gas Turbine Engines ... Hot Corrosion of SiC Cermaic Matrix Composites in Marine CombustionĀ...
A Study of Self-Aligned SONOS-type Nonvolatile Memory with Internal Block Oxide.
??In this thesis, we have proposed the self-aligned SONOS-type nonvolatile memory with internal block oxide (SAIBO-SONOS NVM). We use the dry etching method to buryģ (more)
Hsu, Shih-wen
Mechanistic, sensitivity, and uncertainty studies of the atmospheric oxidation of dimethylsulfide
The global-scale emissions and reactivity of dimethylsulfide (CH3SCH3, DMS) make it an integral component in the atmospheric sulfur cycle. DMS is rapidly oxidized in the atmosphere by a complex gas-phase mechanism involving ...
Lucas, Donald David, 1969-
Fundamental studies of heterostructured oxide thin film electrocatalysts for oxygen reduction at high temperatures
Searching for active and cost-effective catalysts for oxygen electrocatalysis is essential for the development of efficient clean electrochemical energy technologies. Perovskite oxides are active for surface oxygen exchange ...
Crumlin, Ethan J
Development of quantitative techniques for the study of discharge events during plasma electrolytic oxidation processes
of the substrate thickens by a process similar to conventional anodising. The voltage rises rapidly as the oxide layer thickens, and once the applied potential difference has reached several hundred volts, electrical breakdowns of the growing oxide begin... . Probability distributions of apparent discharge lifetimes were presented for three values of the applied volt- age, each corresponding to a later time during processing. The discharge apparent lifetimes were reported as ? 35? 100 ms at 300 V, ? 35? 260 ms...
Dunleavy, Christopher Squire
The oxidation resistance of binary and ternary zirconium alloys containing 0.5 to 5 wt% niobium and ternary additions of Sn, Cu, W, Mo, Sb, V, Ge, Pd, Pt, Fe, and Mn was studied in steam and air. The lowest oxidation rate was achieved with a Zr--1% Nb--1% Cu alloy. A study of the effect of heat treatment on the alloys showed that either a 24 hour anneal at 580 deg C, or cold-working of the material will result in good oxidation resistance. Some alloys containing high percentages of niobium (20-60 wt%) were examined. All the alloys were susceptible to non-uniform oxidation at long times, leading (in some instances) to cracking of the specimen. Such alloys are not considered reliable for use as structural materials involving long exposures to high temperature water or steam. The rate of hydrogen absorption by alloys containing small additions of niobium was very much less than that found for Zircaloy-2. (auth)
Cox, B.; Chadd, P.G.; Short, J.F.
Adsorption of collagen to indium oxide nanoparticles and infrared emissivity study thereon
Adsorption of collagen to indium oxide nanoparticles was carried out in water-acetone solution at volumetric ratio of 1:1 with pH value varying from 3.2 to 9.3. As indicated by TGA, maximum collagen adsorption to indium oxide nanoparticles occurred at pH of 3.2. It was proposed that noncovalent interactions such as hydrogen bonding, hydrophilic and electrostatic interactions made main contributions to collagen adsorption. The IR emissivity values (8-14 {mu}m) of collagen-adsorbed indium oxide nanoparticles decreased significantly compared to either pure collagen or indium oxide nanoparticles possibly due to the interfacial interactions between collagen and indium oxide nanoparticles. And the lowest infrared emissivity value of 0.587 was obtained at collagen adsorption of 1.94 g/100 g In{sub 2}O{sub 3}. On the chance of improved compatibility with organic adhesives, the chemical activity of adsorbed collagen was further confirmed by grafting copolymerization with methyl methacrylate by formation of polymer shell outside, as evidenced by IR spectrum and transmission electron microscopy.
Zhou Yuming [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China)], E-mail: firstname.lastname@example.com; Shan Yun; Sun Yanqing [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Ju Huangxian [School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)
Five kW Solid Oxide Fuel Cell Demonstration Project: Case Study: Exit Glacier Nature Center Acumentrics Demonstration
This case study documents the demonstration experiences and lessons learned from a 5 kW solid oxide fuel cell system operating on propane at the Kenai Fiords National Park at the Exit Glacier Visitor Center, Seward, Alaska. The case study is one of several fuel cell project case studies under research by EPRI's Distributed Energy Resources Program. This case study is designed to help utilities and other interested parties understand the early applications of fuel cell systems to help them in their resour...
X-ray absorption spectroscopy studies of electrochemically deposited thin oxide films.
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.
Balasubramanian, M.
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-value, dirty feed materials. The Phase I results indicate that a practical means to overcome limitations on biomass slurry feed concentration and preheat temperatuare is to coprocess an auxiliary high heating value material. SWPO coprocessing of tow hgih-water content wastes, partially dewatered sewage sludge and trap grease, yields a scenario for the production of hydrogen at highly competitive prices. It is estimated that there are hundreds if not thousands of potential sites for this technology across the US and worldwide.
History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies
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.
Larry Zirker; Nathan Jerred; Dr. Indrajit Charit; James Cole
A Phenomenological Study of the Metal-Oxide Interface: The Role of Catalysis in Hydrogen Production from Renewable Resources
The truth about Cats: The metal-oxide interface of a Pd-Rh/CeO{sub 2} catalyst was studied in the context of developing active, selective and durable solid catalytic materials for the production of hydrogen from renewables. The presence of a stable contact between finely dispersed transition-metal clusters (Pd and Rh) on the nanoparticles of the CeO{sub 2} support leads to a highly active and stable catalyst for the steam reforming of ethanol.
Idriss, H.; Llorca, J; Chan, S; Blackford, M; Pas, S; Hill, A; Alamgir, F; Rettew, R; Petersburg, C; Barteau, M
A Tentative Modeling Study of the Effect of Wall Reactions on Oxidation Phenomena
temperature diagram of oxidation phenomena in the case of n-butane. Reactions which depend on the type-Ta ignition diagrams for equimolar n-butane/oxygen in an untreated silica vessel, a vessel internally coated Figure 1. Experimental p-Ta ignition diagrams for equimolar n-butane + oxygen mixtures (50 % n- butane
Paris-Sud XI, Universit├® de
Studies on activated carbon capacitor materials loaded with different amounts of ruthenium oxide
speci®c capacitance [4]. However, the cost of ruthenium and its compounds limits its wide spread usage in electric/hybrid vehicles and consumer electronics. Substitutes for Ru oxides do not show compar- able 100 F/g, much lower than 720 F/g reported for amorphous RuO2. Wilde et al. [9] synthesized SrRuO3
Popov, Branko N.
This task involves theoretical analysis of possible alternative metallic interconnect schemes including: Ni and dispersion-strengthened Ni, low CTE alloys based on Fe-Ni (Invar), coatings to suppress evaporation, and incorporation of high conductivity paths. The most promising systems are being evaluated experimentally with regard to durability and oxide conductivity.
Hammer, J.; Laney, S.; Jackson, W.; Pettit, F.; Meier, J.; Dhanaraj, N.; Beuth, J.
Kinetics, FTIR and controlled atmosphere EXAFS study of the effect of chlorine on Pt supported catalysts during oxidation reactions.
The poisoning effect of Cl on the activity of Pt-supported catalysts for CO, methane, and ethane oxidation has been investigated by kinetic studies and in situ IR and controlled atmosphere EXAFS spectroscopies. Catalysts containing 1.5% Pt/Al{sub 2}O{sub 3} were prepared by incipient wetness from H{sub 2}PtCl{sub 6} and Pt(NH{sub 3}){sub 4}(NO{sub 3}){sub 2} precursors. The reduced catalysts have similar dispersion (0.8) as estimated by H{sub 2} chemisorption. The Cl-free catalyst was 10 times more active than the Cl-containing catalyst during CO and ethane oxidation. Addition of HCl to the Cl-free catalyst rendered its activity identical to the catalyst prepared from Cl-containing precursors. The presence of Cl also affects the activity of 2% Pt/SiO{sub 2} catalysts, but to a lower extent. On the Cl-free oxidation catalyst, Pt-Pt and Pt-O bonds were detected using EXAFS, suggesting that the reduced metal particles are not fully oxidized under the reaction conditions. Additionally, chemisorption of CO by the oxidized catalyst indicates that a portion of the reduced Pt atoms is exposed to the reactants. On the Cl-containing catalyst, there are also Pt-Cl as well as Pt-Pt and Pt-O bonds. The later catalyst, however, does not chemisorb CO, indicating that there are no reduced surface Pt atoms. The effect of Cl poisoning on the oxidation activity of Pt supported on silica is similar to that on alumina. IR results show that chlorine significantly reduces the amount of CO adsorbed on metallic Pt sites. At low temperature there is little CO adsorbed on the Cl-containing Pt/silica catalyst, while at higher temperature the amount of adsorbed CO increases, likely due to reduction of the oxidized surface. The catalyst activities correlate well with the amount of reduced surface sites, and a model is proposed to explain the mechanism of chloride poisoning, which is shown to occur mainly by site blocking.
Gracia, F. J.; Wolf, E. E.; Miller, J. T.; Kropf, A. J.; Chemical Engineering; Univ. of Notre Dame; BP Research Center
Mechanistic Studies of Methanol Oxidation to Formaldehyde on Isolated Vanadate Sites Supported on Mcm-48
The mechanism of methanol oxidation to formaldehyde catalyzed by isolated vanadate species supported on silica has been investigated by in situ Raman and TPD/TPO experiments. Raman, XANES, and EXAFS were used to characterize the V-MCM-48 sample, prepared with a loading of 0.3 V/nm{sup 2}, and it is concluded that the oxidized form of the vanadium is isolated VO{sub 4} units. The VO{sub 4} species consist of one V=O bond and three V-O-Si bonds in a distorted tetrahedral geometry. Methanol reacts reversibly, at a ratio of approximately 1 methanol per V, with one V-O-Si to produce both V-OCH{sub 3}/Si-OH and V-OH/Si-OCH{sub 3} group pairs in roughly equivalent concentrations. Formaldehyde is formed from the methyl group of V-OCH{sub 3}, most likely by the transfer of one H atom to the V=O bond of the vanadium containing the methoxide group. Formaldehyde is formed in nearly equal concentrations both in the presence and in the absence of gas-phase oxygen. CO and H{sub 2} are produced by the decomposition of CH{sub 2}O at higher temperature. In the absence of O{sub 2}, Si-OCH{sub 3} groups undergo hydrogenation to form CH{sub 4}, and in the presence of O{sub 2}, these groups are oxidized to COx (x = 1, 2) and H{sub 2}O above 650 K. Under steady-state reaction conditions, CH{sub 2}O is produced as the dominant product of methanol oxidation at temperatures below 650 K with an apparent activation energy of 23 kcal/mol. Schemes for the product flows during both TPD and TPO experiments, along with proposed surface intermediates, are presented.
Bronkema, J.L.; Bell, A.T.; /LBL, Berkeley /UC, Berkeley, Chem. Eng. Dept.
Study on the oxidation and reduction of tungsten surface for sub-50 nm patterning process
The oxidation characteristics of tungsten line pattern during the carbon-based mask-layer removal process using oxygen plasmas have been investigated for sub-50 nm patterning processes, in addition to the reduction characteristics of the WO{sub x} layer formed on the tungsten line surface using hydrogen plasmas. The surface oxidation of tungsten lines during the mask layer removal process could be minimized by using low-temperature (300 K) plasma processing for the removal of the carbon-based material. Using this technique, the thickness of WO{sub x} on the tungsten line could be decreased to 25% compared to results from high-temperature processing. The WO{sub x} layer could also be completely removed at a low temperature of 300 K using a hydrogen plasma by supplying bias power to the tungsten substrate to provide a activation energy for the reduction. When this oxidation and reduction technique was applied to actual 40-nm-CD device processing, the complete removal of WO{sub x} formed on the sidewall of tungsten line could be observed.
Kim, Jong Kyu; Nam, Seok Woo; Cho, Sung Il; Jhon, Myung S.; Min, Kyung Suk; Kim, Chan Kyu; Jung, Ho Bum; Yeom, Geun Young [Memory Division Semiconductor Business, Samsung Electronics, San No. 16 Banwol-Ri, Taean-Eup, Hwasung-City, Gyeonggi-Do 449-711, South Korea and Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Memory Division Semiconductor Business, Samsung Electronics, San No. 16 Banwol-Ri, Taean-Eup, Hwasung-City, Gyeonggi-Do 449-711 (Korea, Republic of); Department of Chemical Engineering and Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)
Studies involving high temperature desulfurization/regeneration reactions of metal oxides for fuel cell development. Final report
Research conducted at Giner, Inc. during 1981 to 1983 under the present contract has been a continuation of the investigation of a high temperature regenerable desulfurization process capable of reducing the sulfur content in coal gases from 200 ppM to 1 ppM. The overall objective has been the integration of a coal gasifier with a molten carbonate fuel cell, which requires that the sulfur content be below 1 ppM. Commercially available low temperature processes incur an excessive energy penalty. Results obtained with packed-bed and fluidized bed reactors have demonstrated that a CuO/ZnO mixed oxide sorbent is regenerable and capable of lowering the sulfur content (as H/sub 2/S and COS) from 200 ppM in simulated hot coal-derived gases to below 1 ppM level at 600 to 650/sup 0/C. Four potential sorbents (copper, tungsten oxide, vanadium oxide and zinc oxide) were initially selected for experimental use in hot regenerable desulfurization in the temperature range 500 to 650/sup 0/C. Based on engineering considerations, such as desulfurization capacity in per weight or volume of sorbents, a coprecipitated CuO/ZnO was selected for further study. A structural reorganization mechanism, unique to mixed oxides, was identified: the creation of relatively fine crystallites of the sulfided components (Cu/sub 2/S and ZnS) to counteract the loss of surface area due to sintering during regeneration. Studies with 9 to 26% water vapor in simulated coal gases show that sulfur levels below 1 ppM can be achieved in the temperature range of 500/sup 0/ to 650/sup 0/C. The ability of CuO/ZnO to remove COS, CS/sub 2/ and CH/sub 3/SH at these conditions has been demonstrated in this study. Also a previously proposed pore-plugging model was further developed with good success for data treatment of both packed bed and fluidized-bed reactors. 96 references, 42 figures, 21 tables.
Jalan, V.
Chemical Synthesis of Nano-Sized particles of Lead Oxide and their Characterization Studies
The quantum dots of semiconductor display novel and interesting phenomena that have not been in the bulk material. The color tunability is one of the most attractive characteristics in II-VI semiconductor nanoparticles such as CdS, ZnS, CdSe, ZnSe and PbO. In this work, the semiconductor lead oxide nanoparticles are prepared by chemical method. The average particle size, specific surface area, crystallinity index are estimated from XRD analysis. The structural, functional groups and optical characters are analyzed with using of SEM, FTIR and UV- Visible techniques. The optical band gap value has also been determined.
M. Alagar; T. Theivasanthi; A. Kubera Raja
Fischer-Tropsch synthesis: Moessbauer studies of pretreated ultrafine iron oxide catalysts
Moessbauer spectroscopy indicates that a 24 hour-pretreatment in CO at 260{degrees}C and 8 atm. in a tetralin solvent almost completely converts uftrafine iron oxide (about 3 nm) to iron carbide. However, pretreatment in hydrogen under the same conditions resulted in reduction of about 33% of the iron to metallic Fe; the remainder was Fe{sub 3}O{sub 4}. Exposure of the CO pretreated catalyst to a 1:1 HDCO synthesis gas resulted in the gradual reoxidation of the carbides to Fe{sub 3}O{sub 4}. During the first 2 hours of exposure of the H{sub 2} pretreated sample to synthesis gas,.the metallic Fe was converted to iron carbides. Further exposure of the H{sub 2} pretreatment sample to synthesis gas did not result in a composition change of the catalyst. Therefore, it is concluded that iron carbides with different oxidation characteristics were formed in these two cases.
Chenshi Huang; Davis, B.H. (Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Research); Rao, K.R.P.M.; Huffman, G.P.; Huggins, F.E. (Kentucky Univ., Lexington, KY (United States). Inst. for Mining and Minerals Research)
Solid-State 17O NMR Study of Benzoic Acid Adsorption On Metal Oxide Surfaces
Solid-state 17O NMR spectra of 17O-labeled benzoic and anisic acids are reported and benzoic acid is used to probe the surface of metal oxides. Complexes formed when benzoic acid is dry-mixed with mesoporous silica, and nonporous titania and alumina are characterized. Chemical reactions with silica are not observed. The nature of benzoic acid on silica is a function of the water content of the oxide. The acid disperses in the pores of the silica if the silica is in equilibrium with ambient laboratory humidity. The acid displays high mobility as evidenced by a liquid-like, Lorentzian resonance. Excess benzoic acid remains as the crystalline hydrogen-bonded dimer. Benzoic acid reacts with titania and alumina surfaces in equilibrium with laboratory air to form the corresponding titanium and aluminum benzoates. In both materials the oxygen of the 17O-labeled acid is bound to the metal, showing the reaction proceeds by bond formation between oxygen deficient metal sites and the oxygen of the carboxylic acid. 27Al MAS NMR confirms this mechanism for the reaction on alumina. Dry mixing of benzoic acid with alumina rapidly quenches pentacoordinate aluminum sites, excellent evidence that these sites are confined to the surface of the alumina particles.
Hagaman, Edward {Ed} W [ORNL; Chen, Banghao [ORNL; Jiao, Jian [ORNL; Parsons, Williams [Oak Ridge National Laboratory (ORNL)
[Fundamental studies in oxidation-reduction in relation to water photolysis]. Final report, February 15, 1990--July 31, 1993
Broad objectives are to improve the conceptual view of ways in which membranes and interfaces can be used to control chemical reactivity. Focus was on three elementary processes central to developing membrane-based integrated chemical systems for water photolysis or related photoconversion/photostorage processes. It was sought to identify the influence of interfaces on charge separation/recombination reactions, pathways for transmembrane charge separation across hydrocarbon bilayer membranes, and mechanisms of water oxidation catalyzed by transition metal coordination complexes. The supramolecular assemblies studied comprise primarily small unilamellar vesicles doped with amphiphilic viologens (N,N`dialkyl-4,4`-bipyridinium ions) which can function as transmembrane charge relays.
Fundamental Studies of Irradiation-Induced Defect Formation and Fission Product Dynamics in Oxide Fuels
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.
Stubbins, James
A Feasibility Study of Steelmaking by Molten Oxide Electrolysis (TRP9956)
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.
Donald R. Sadoway; Gerbrand Ceder
Study of metallic materials for solid oxide fuel cell interconnect applications.
Metallic interconnect acts as a gas separator and a gas distributor and therefore, it needs to function adequately in two widely different environments. The interconnect material will be exposed to air on one side and natural gas or coal-derived synthesis gas on the other side. The viable material for the interconnect application must be resistant not only to oxidation but also carburization in hydrocarbon containing low-oxygen environments. In addition, the scales that develop on the exposed surfaces must possess adequate electrical conductivity for them to function as current leads over long service life of the fuel cell. This report addresses five topics of interest for the development of metallic interconnects with adequate performance in fuel cells for long service life. The research conducted over the years and the conclusions reached were used to identify additional areas of research on materials for improved performance of components, especially metallic interconnects, in the complex fuel cell environments. This report details research conducted in the following areas: measurement of area specific electrical resistivity, corrosion performance in dual gas environments by experiments using alloy 446, long term corrosion performance of ferritic and austenitic alloys in hydrogen and methane-reformed synthesis fuel-gas environments, approaches to reduce the area resistance of metallic interconnect, and reduction of electrical resistivity of alumina scales on metallic interconnect. Based on the key requirements for metallic interconnects and the data developed on the corrosion behavior of candidate materials in meeting those requirements, several areas are recommended for further research to develop metallic interconnects with acceptable and reliable long-term performance in solid oxide fuel cells.
Natesan, K.; Zeng, Z.; Nuclear Engineering Division
Structural oxidation state studies of the manganese cluster in the oxygen evolving complex of photosystem II
X-ray absorption spectroscopy (XAS) was performed on Photosystem II (PSII)-enriched membranes prepared from spinach to explore: (1) the correlation between structure and magnetic spin state of the Mn cluster in the oxygen evolving complex (OEC) in the S{sub 2} state; and (2) the oxidation state changes of the Mn cluster in the flash-induced S-states. The structure of the Mn cluster in the S{sub 2} state with the g{approx}4 electron paramagnetic resonance (EPR) signal (S{sub 2}-g4 state) was compared with that in the S{sub 2} state with multiline signal (S{sub 2}-MLS state) and the S{sub 1} state. The S{sub 2}-g4 state has a higher XAS inflection point energy than that of the S{sub 1} state, indicating the oxidation of Mn in the advance from the S{sub 1} to the S{sub 2}-g4 state. Differences in the edge shape and in the extended X-ray absorption fine structure (EXAFS) show that the structure of the Mn cluster in the S{sub 2}-g4 state is different from that in the S{sub 2}-MLS or the S{sub 1} state. In the S{sub 2}-g4 state, the second shell of backscatterers from the Mn absorber contains two Mn-Mn distances of 2.73 {angstrom} and 2.85 {angstrom}. Very little distance disorder exists in the second shell of the S{sub 1} or S{sub 2}-MLS states. The third shell of the S{sub 2}-g4 state at about 3.3 {angstrom} also contains increased heterogeneity relative to that of the S{sub 2}-MLS or the S{sub 1} state. Various S-states were prepared at room-temperature by saturating, single-turnover flashes. The flash-dependent oscillation in the amplitude of the MLS was used to characterize the S-state composition and to construct {open_quotes}pure{close_quotes} S-state Mn K-edge spectra. The edge position shifts to higher energy by 1.8 eV upon the S{sub 1} {yields} S{sub 2} transition.
Liang, W.
Computational studies of catechol and water interactions with titanium oxide nanoparticles.
The interaction of catechol and water with titanium oxide nanoparticles was investigated using ab initio molecular orbital theory and density functional theory. Hydrogen-terminated TiO{sub 2} clusters were used to model the surface of anatase nanoparticles. The calculations indicate that catechol reacts with a Ti{double_bond}O defect site on the surface to form a bidentate structure that is favored over dissociative or molecular adsorption on the (101) anatase surface. The dissociative adsorption of catechol at the defect site leads to a much larger red shift in the TiO{sub 2} excitation energy than molecular adsorption on the (101) anatase surface on the basis of ZINDO/S calculations. This is consistent with recent experimental results on small (<2 nm) titania nanoparticles. The calculations on water adsorption indicate that it can also add to the Ti{double_bond}O double bond site. However, molecular adsorption of water on the (101) anatase surface is more favorable.
Redfern, P. C.; Zapol, P.; Curtiss, L. A.; Rajh, T.; Thurnauer, M.
Surface chemistry of coated lithium manganese nickel oxide thin film cathodes studied by XPS
The effect of coating high voltage LiMn1.5Ni0.5O4 spinel cathode thin films with three metal oxide thin layers is discussed. The changes in surface chemistry of the electrodes are measured by X-ray photoelectron spectroscopy. ZnO is found to decompose during the first charge whereas Al2O3 and ZrO2 are stable for more than 100 cycles. ZrO2, however, importantly limits the available Li storage capacity of the electrochemical reaction due to poorer kinetics. Al2O3 offers the best results in term of capacity retention. Upon cycling, the evidence of a signal at 75.4 eV in the Al2p binding energy spectrum indicates the partial conversion of Al2O3 into Al2O2F2. Moreover, the continuous formation of PEO , esters and LixPOyFz compounds on the surface of the electrodes is found for all coating materials.
Baggetto, Loic [ORNL; Dudney, Nancy J [ORNL; Veith, Gabriel M [ORNL
Asphalt Oxidation Kinetics and Pavement Oxidation Modeling
Most paved roads in the United States are surfaced with asphalt. These asphalt pavements suffer from fatigue cracking and thermal cracking, aggravated by the oxidation and hardening of asphalt. This negative impact of asphalt oxidation on pavement performance has not been considered adequately in pavement design. Part of the reason is that the process of asphalt oxidation in pavement is not well understood. This work focused on understanding the asphalt oxidation kinetics and on developing pavement oxidation model that predicts asphalt oxidation and hardening in pavement under environmental conditions. A number of asphalts were studied in laboratory condition. Based on kinetics data, a fast-rate ? constant-rate asphalt oxidation kinetics model was developed to describe the early nonlinear fast-rate aging period and the later constant-rate period of asphalt oxidation. Furthermore, reaction kinetics parameters for the fast-rate and constant-rate reactions were empirically correlated, leading to a simplified model. And the experimental effort and time to obtain these kinetics parameters were significantly reduced. Furthermore, to investigate the mechanism of asphalt oxidation, two antioxidants were studied on their effectiveness. Asphalt oxidation was not significantly affected. It was found that evaluation of antioxidant effectiveness based on viscosity only is not reliable. The asphalt oxidation kinetics model was incorporated into the pavement oxidation model that predicts asphalt oxidation in pavement. The pavement oxidation model mimics the oxidation process of asphalt in real mixture at pavement temperatures. A new parameter, diffusion depth, defined the oxygen diffusion region in the mastic. A field calibration factor accounted for the factors not considered in the model such as the effect of small aggregate particles on oxygen diffusion. Carbonyl area and viscosity of binders recovered from field cores of three pavements in Texas were measured and were used for model calibration and validation. Results demonstrated that the proposed model estimates carbonyl growth over time in pavement, layer-by-layer, quite well. Finally, this work can be useful for incorporating asphalt oxidation into a pavement design method that can predict pavement performance with time and for making strategic decisions such as optimal time for maintenance treatments.
Jin, Xin
Nuclear waste treatment - Studying the mixed ion type effects and concentration on the behaviour of oxide dispersions
In order to gain good control over a particulate dispersion it is necessary to accurately characterise the strength of inter-particle forces that may be operating. Such control is not routinely used, as yet, in the nuclear industry despite the possible benefits. We are investigating the impact of mixed electrolyte systems, for example NaCl and Na{sub 2}SO{sub 4}, on the stability of oxide simulant particle dispersions. The electro-acoustic zeta potentials and shear yield stresses for concentrated dispersions have been measured across a range of pH conditions and electrolyte concentrations (0.001 M - 1.0 M). This paper summarizes initial data from these studies showing how the shear yield stress of concentrated aqueous oxide particle dispersions, can be adjusted through regulation of pH and the addition of background electrolytes (salt). The yield stress as a function of pH for these dispersions in mixed electrolytes showed a direct correlation with corresponding measurements of the zeta potential. Changes in the background electrolyte concentration or type were seen to cause a shift in the position of the isoelectric point (iep). Measurements of the shear yield stress showed a maximum at the iep corresponding to the position of maximum instability in the suspension. The consequences of these data for the efficient treatment of solid-liquid systems will be discussed. (authors)
Omokanye, Qanitalillahi; Biggs, Simon [Institute of Particle Science and Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)
Mixture Preparation and Nitric Oxide Formation in a GDI Engine studied by Combined Laser Diagnostics and Numerical Modeling
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.
Volker Sick; Dennis N. Assanis
A detailed kinetic modeling study of toluene oxidation in a premixed laminar flame
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.
Tian, Z; Pitz, W J; Fournet, R; Glaude, P; Battin-Leclerc, F
Study of the oxidation state of arsenic and uranium in individual particles from uranium mine tailings, Hungary
Uranium ore mining and milling have been terminated in the Mecsek Mountains (southwest Hungary) in 1997. Mine tailings ponds are located between two important water bases, which are resources of the drinking water of the city of Pecs and the neighbouring villages. The average U concentration of the tailings material is 71.73 {mu}g/g, but it is inhomogeneous. Some microscopic particles contain orders of magnitude more U than the rest of the tailings material. Other potentially toxic elements are As and Pb of which chemical state is important to estimate mobility, because in mobile form they can risk the water basis and the public health. Individual U-rich particles were selected with solid state nuclear track detector (SSNTD) and after localisation the particles were investigated by synchrotron radiation based microanalytical techniques. The distribution of elements over the particles was studied by micro beam X-ray fluorescence ({mu}-XRF) and the oxidation state of uranium and arsenic was determined by micro X-ray absorption near edge structure ({mu}-XANES) spectroscopy. Some of the measured U-rich particles were chosen for studying the heterogeneity with {mu}-XRF tomography. Arsenic was present mainly in As(V) and uranium in U(VI) form in the original uranium ore particles, but in the mine tailings samples uranium was present mainly in the less mobile U(IV) form. Correlation was found between the oxidation state of As and U in the same analyzed particles. These results suggest that dissolution of uranium is not expected in short term period. (authors)
Alsecz, A.; Osan, J.; Palfalvi, J.; Torok, Sz. [Hungarian Academy of Science, KFKI, Atomic Energy Research Institute, P. O. Box 49, H-1525 Budapest (Hungary); Sajo, I. [Chemical Research Centre of the Hungarian Academy of Sciences, Pusztaszeri ut 59-67, H-1025 Budapest (Hungary); Mathe, Z. [Mecsek Ore Environment, H-7614 Pecs, P.O. Box 121 (Hungary); Simon, R. [Forschungsgruppe Synchrotronstrahlung, Research Centre, D-76021 Karlshruhe (Germany); Falkenberg, G. [Hamburger Synchrotronstralungslabor (HASYLAB) at Deutsches Elektronen-Synchrotron (DESY), Notkestr. 85, 22607 Hamburg (Germany)
Resistance Switching of Electrodeposited Cuprous OxideThin Films
Oxidation Potentials of Functionalized Sulfone Solvents for High-Voltage Li-Ion Batteries: A Computational Study
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.
Shao, Nan [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL; Jiang, Deen [ORNL
Chemistry of carbonaceous aerosols : studies of atmospheric processing and OH-initiated oxidation
Carbonaceous aerosols are among the most prevalent yet least understood constituents of the atmosphere, particularly in urban environments. We have performed analyses of field samples and laboratory studies to probe the ...
Johnson, Kirsten S. (Kirsten Sue)
Study of scale formation on AISI 316L in simulated solid oxide fuel cell bi-polar environments
Significant progress made towards reducing the operating temperature of solid oxide fuel cells (SOFC) from {approx}1000 C to {approx}600 C is expected to permit the use of metallic materials with substantial cost reduction. One of the components in a SOFC stack to be made of metallic materials is a bipolar separator, also called an interconnect. It provides electrical connection between individual cells and serves as a gas separator to prevent mixing of the fuel and air. At operating temperature, the material selected for interconnects should possess good chemical and mechanical stability in complex fuel and oxidant gaseous environments, good electrical conductivity, and a coefficient of thermal expansion (CTE) that matches that of the cathode, anode, and electrolyte components. Cr2O3 scale-forming alloys appear to be the most promising candidates. There appears to be a mechanism whereby the environment on the fuel side of a stainless steel interconnect changes the corrosion behavior of the metal on the air side. The corrosion behavior of 316L stainless steel simultaneously exposed to air on one side and H2+3%H2O on the other at 907 K was studied using X-ray diffraction (XRD) and Raman spectroscopy. The electrical property of the investigated material was determined in terms of area-specific resistance (ASR). The chemical and electrical properties of 316L exposed to a dual environment of air/ (H2+H2O) were compared to those of 316L exposed to a single environment of air/air.
Ziomek-Moroz, M.; Covino, Bernard S., Jr.; Cramer, Stephen D.; Holcomb, Gordon R.; Bullard, Sophie J.; Singh (PNNL), P.; Windisch, C.F., Jr. (PNNL)
Study of Heterogeneouse Processes Related to the Chemistry of Tropospheric Oxidants and Aerosols
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
Davidovits, Paul; Worsnop, D R; Jayne, J T; Colb, C E
Carbon contamination and oxidation of Au surfaces under extreme ultraviolet radiation: An x-ray photoelectron spectroscopy study
Carbon contamination and oxidation of Au surfaces under extreme ultraviolet radiation: An x 2012) Extreme ultraviolet (EUV) radiation-induced carbon contamination and oxidation of Au surfaces modification during EUV exposure. XPS analysis showed that total carbon contamination (C 1s peak
Harilal, S. S.
Pulmonary toxicity and kinetic study of Cy5.5-conjugated superparamagnetic iron oxide nanoparticles by optical imaging
Recent advances in the development of nanotechnology and devices now make it possible to accurately deliver drugs or genes to the lung. Magnetic nanoparticles can be used as contrast agents, thermal therapy for cancer, and be made to concentrate to target sites through an external magnetic field. However, these advantages may also become problematic when taking into account safety and toxicological factors. This study demonstrated the pulmonary toxicity and kinetic profile of anti-biofouling polymer coated, Cy5.5-conjugated thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPION) by optical imaging. Negatively charged, 36 nm-sized, Cy5.5-conjugated TCL-SPION was prepared for optical imaging probe. Cy5.5-conjugated TCL-SPION was intratracheally instilled into the lung by a non-surgical method. Cy5.5-conjugated TCL-SPION slightly induced pulmonary inflammation. The instilled nanoparticles were distributed mainly in the lung and excreted in the urine via glomerular filtration. Urinary excretion was peaked at 3 h after instillation. No toxicity was found under the concentration of 1.8 mg/kg and the half-lives of nanoparticles in the lung and urine were estimated to be about 14.4 {+-} 0.54 h and 24.7 {+-} 1.02 h, respectively. Although further studies are required, our results showed that Cy5.5-conjugated TCL-SPION can be a good candidate for use in pulmonary delivery vehicles and diagnostic probes.
Cho, Wan-Seob [Division of Toxicologic Pathology, Department of Toxicological Research, National Institute of Toxicological Research, Korea Food and Drug Administration, 231 Jinhoungno Eunpyung-ku, Seoul 122-704 (Korea, Republic of); Respiratory Medicine Unit, ELEGI/Colt Laboratory, Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ (United Kingdom)], E-mail: firstname.lastname@example.com; Cho, Minjung; Kim, Seoung Ryul; Choi, Mina; Lee, Jeong Yeon; Han, Beom Seok [Division of Toxicologic Pathology, Department of Toxicological Research, National Institute of Toxicological Research, Korea Food and Drug Administration, 231 Jinhoungno Eunpyung-ku, Seoul 122-704 (Korea, Republic of); Park, Sue Nie [Division of Genetic Toxicology, Department of Toxicological Research, National Institute of Toxicological Research, Korea Food and Drug Administration, 231 Jinhoungno Eunpyung-ku, Seoul 122-704 (Korea, Republic of); Yu, Mi Kyung; Jon, Sangyong [Research Center for Biomolecular Nanotechnology, Department of Life Science, Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712 (Korea, Republic of); Jeong, Jayoung [Division of Toxicologic Pathology, Department of Toxicological Research, National Institute of Toxicological Research, Korea Food and Drug Administration, 231 Jinhoungno Eunpyung-ku, Seoul 122-704 (Korea, Republic of)
Soft X-Ray Spectroscopic Study of Dense Strontium-Doped Lanthanum Manganite Cathodes for Solid Oxide Fuel Cell Applications
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.
L Piper; A Preston; S Cho; A DeMasi; J Laverock; K Smith; L Miara; J Davis; S Basu; et al.
Multifunctional Oxides
3) Electric, ferroelectric, magnetic and photonic properties of oxides 4) Theoretical modeling of epitaxial growth, interfaces and microstructures 5) CompositionĀ...
FAST OXIDE BREEDER-REACTOR. PART I. PARAMETRIC STUDY OF 300(e) MW REACTOR CORE
Physics scoping studies of a 300-Mw(e) PuO/sub 2/-UO/sub 2/-fueled fast- breeder reactor are reported. Physics design parameters that effect fuel costs, full conservation, and reactor safety were evaluated for use in the selection of parameters for a reference design. The total breeding ratio varied from 1.1 to 1.5 in the range of parameters corsidered. Plutonium core loading ranged from 500 to 1500 kg. Doubling time was found to be reduced by high-density fuel and low steel content. A compromise figure on fuel-rod range of sizes (about 100 mils) yields a 5 operating reactivity and a small, negative sodium temperature coefficient. (J.R.D.)
Greebler, P.; Aline, P.; Sueoka, J.
TEM Study on the Evolution of Ge Nanocrystals in Si Oxide Matrix as a Function of Ge Concentration and the Si Reduction Process
Growth and evolution of germanium (Ge) nanocrystals embedded into a silicon oxide (SiO?) system have been studied based on the Ge content of co-sputtered Ge-SiO? films using transmission electron microscopy (TEM) and X-ray ...
Chew, Han Guan
Thermal Oxidation of Titanium Wires
Structural and Thermal Study of Al2O3 Produced by Oxidation of Al-Powders Mixed with Corn Starch Ę Study of Silicon Carbide/Silicon Nitride CompositeĀ...
The growing concerns for the environment and increasingly stringent standards for NO emission have presented a major challenge to control NO emissions from electric utility plants and automobiles. Catalytic decomposition of NO is the most attractive approach for the control of NO emission for its simplicity. Successful development of an effective catalyst for NO decomposition will greatly decrease the equipment and operation cost of NO control. Due to lack of understanding of the mechanism of NO decomposition, efforts on the search of an effective catalyst have been unsuccessful. Scientific development of an effective catalyst requires fundamental understanding of the nature of active site, the rate-limiting step, and an approach to prolong the life of the catalyst. The authors have investigated the feasibility of two novel approaches for improving catalyst activity and resistance to sintering. The first approach is the use of silanation to stabilize metal crystallites and supports for Cu-ZSM-5 and promoted Pt catalysts; the second is utilization of oxygen spillover and desorption to enhance NO decomposition activity. The silanation approach failed to stabilize Cu-ZSM-5 activity under hydrothermal condition. Silanation blocked the oxygen migration and inhibited oxygen desorption. Oxygen spillover was found to be an effective approach for promoting NO decomposition activity on Pt-based catalysts. Detailed mechanistic study revealed the oxygen inhibition in NO decomposition and reduction as the most critical issue in developing an effective catalytic approach for controlling NO emission.
A study of oxidative stress induced by non-thermal plasma-activated water for bacterial damage
Ar/O{sub 2} (2%) cold plasma microjet was used to create plasma-activated water (PAW). The disinfection efficacy of PAW against Staphylococcus aureus showed that PAW can effectively disinfect bacteria. Optical emission spectra and oxidation reduction potential results demonstrated the inactivation is attributed to oxidative stress induced by reactive oxygen species in PAW. Moreover, the results of X-ray photoelectron spectroscopy, atomic absorption spectrometry, and transmission electron microscopy suggested that the chemical state of cell surface, the integrity of cell membrane, as well as the cell internal components and structure were damaged by the oxidative stress.
Zhang, Qian; Ma, Ruonan; Tian, Ying [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China)] [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Liang, Yongdong; Feng, Hongqing [College of Engineering, Peking University, Beijing 100871 (China)] [College of Engineering, Peking University, Beijing 100871 (China); Zhang, Jue; Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China) [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)
Studies of Scale Formation and Kinetics of Crofer 22 APU and Haynes 230 in Carbon Oxide-Containing Environment for SOFC Applications
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.
Ziomek-Moroz, M.; Covino, B.S., Jr.; Holcomb, G.R.; Bullard, S.J.; Penner, L.R.
In-situ X-ray photoelectron spectroscopy studies of water on metals and oxides at ambient conditions
X-ray photoelectron spectroscopy (XPS) is a powerful tool for surface and interface analysis, providing the elemental composition of surfaces and the local chemical environment of adsorbed species. Conventional XPS experiments have been limited to ultrahigh vacuum (UHV) conditions due to a short mean free path of electrons in a gas phase. The recent advances in instrumentation coupled with third-generation synchrotron radiation sources enables in-situ XPS measurements at pressures above 5 Torr. In this review, we describe the basic design of the ambient pressure XPS setup that combines differential pumping with an electrostatic focusing. We present examples of the application of in-situ XPS to studies of water adsorption on the surface of metals and oxides including Cu(110), Cu(111), TiO2(110) under environmental conditions of water vapor pressure. On all these surfaces we observe a general trend where hydroxyl groups form first, followed by molecular water adsorption. The importance of surface OH groups and their hydrogen bonding to water molecules in water adsorption on surfaces is discussed in detail.
Salmeron, Miquel; Yamamoto, S.; Bluhm, H.; Andersson, K.; Ketteler, G.; Ogasawara, H.; Salmeron, M.; Nilsson, A.
Cathodoluminescence of uranium oxides
The cathodoluminescence of uranium oxide surfaces prepared in-situ from clean uranium exposed to dry oxygen was studied. The broad asymmetric peak observed at 470 nm is attributed to F-center excitation.
Winer, K.; Colmenares, C.; Wooten, F.
Oxidative Degradation of Monoethanolamine
Oxidative Degradation of Monoethanolamine Oxidative Degradation of Monoethanolamine Susan Chi Gary T. Rochelle* (email@example.com, 512-471-7230) The University of Texas at Austin Department of Chemical Engineering Austin, Texas 78712 Prepared for presentation at the First National Conference on Carbon Sequestration, Washington, DC, May 14-17, 2001 Abstract Oxidative degradation of monoethanolamine (MEA) was studied under typical absorber condition of 55┬░C. The rate of evolution of NH 3 , which was indicative of the overall rate of degradation, was measured continuously in a batch system sparged with air. Dissolved iron from 0.0001 mM to 1 mM yields oxidation rates from 0.37 to 2 mM/hr in MEA solutions loaded with 0.4 mole CO 2 / mole MEA. Ethylenediaminetetraacetic acid (EDTA) and N,N-bis(2- hydroxyethyl)glycine effectively decrease the rate of oxidation in the presence of iron by 40 to
A validation of the first genome-wide association study of calcaneus ultrasound parameters in the European Male Ageing Study
centre used the same machine model, which was calibrated daily with the physical phantom provided by the manufacturer. Out- puts included broadband ultrasound attenuation (BUA) (dB/MHz) and speed of sound (SOS) (m/s). Quality con- trol (QC) was performed... in each centre following the instructions of the manufacturer. All QC results were compiled and checked for stability throughout the study in Leuven. To ascertain the short-term precision of the method in this population, duplicate measurements were...
Roshandel, Delnaz; Thomson, Wendy; Pye, Stephen R; Boonen, Steven; Borghs, Herman; Vanderschueren, Dirk; Huhtaniemi, Ilpo T; Adams, Judith E; Ward, Kate A; Bartfai, Gyorgy; Casanueva, Felipe; Finn, Joseph D; Forti, Gianni; Giwercman, Aleksander; Han, Thang S; Kula, Krzysztof; Lean, Michael E; Pendleton, Neil; Punab, Margus; Silman, Alan J; Wu, Frederick C; Holliday, Kate L; O'Neill, Terence W; EMAS Study Group
Final Report - Phase II - Biogeochemistry of Uranium Under Reducing and Re-oxidizing Conditions: An Integrated Laboratory and Field Study
Our understanding of subsurface microbiology is hindered by the inaccessibility of this environment, particularly when the hydrogeologic medium is contaminated with toxic substances. Past research in our labs indicated that the composition of the growth medium (e.g., bicarbonate complexation of U(VI)) and the underlying mineral phase (e.g., hematite) significantly affects the rate and extent of U(VI) reduction and immobilization through a variety of effects. Our research was aimed at elucidating those effects to a much greater extent, while exploring the potential for U(IV) reoxidation and subsequent re-mobilization, which also appears to depend on the mineral phases present in the system. The project reported on here was an extension ($20,575) of the prior (much larger) project. This report is focused only on the work completed during the extension period. Further information on the larger impacts of our research, including 28 publications, can be found in the final report for the following projects: 1) Biogeochemistry of Uranium Under Reducing and Re-oxidizing Conditions: An Integrated Laboratory and Field Study Grant # DE-FG03-01ER63270, and 2) Acceptable Endpoints for Metals and Radionuclides: Quantifying the Stability of Uranium and Lead Immobilized Under Sulfate Reducing Conditions Grant # DE-FG03-98ER62630/A001 In this Phase II project, the toxic effects of uranium(VI) were studied using Desulfovibrio desulfuricans G20 in a medium containing bicarbonate or 1, 4-piperazinediethane sulfonic acid disodium salt monohydrate (PIPES) buffer (each at 30 mM, pH 7). The toxicity of uranium(VI) was dependent on the medium buffer and was observed in terms of longer lag times and in some cases, no measurable growth. The minimum inhibiting concentration (MIC) was 140 ?M U(VI) in PIPES buffered medium. This is 36 times lower than previously reported for D. desulfuricans. These results suggest that U(VI) toxicity and the detoxification mechanisms of G20 depend greatly on the chemical forms of U(VI) present and the buffer present in a system. Phase II of this project was supported at a cost of $20,575 with most funds expended to support Rajesh Sani salary and benefits. Results have been published in a peer reviewed journal article.
Brent Peyton; Rajesh Sani
Preparation and properties of electrically conducting ceramics based on indium oxide-rare earth oxides-hafnium oxides
Electrically conducting refractory oxides based on adding indium oxide to rare earth-stabilized hafnium oxide are being studied for use in magnetohydrodynamic (MHD) generators, fuel cells, and thermoelectric generators. The use of indium oxide generally increases the electrical conductivity. The results of measurements of the electrical conductivity and data on corrosion resistance in molten salts are presented.
Marchant, D.D.; Bates, J.L.
Applications of ReaxFF Reactive Force Fields to Oxidation ...
Symposium, High Temperature Corrosion and Oxidation of Materials ... Carlo tools for studying bulk- and surface oxidation, reactions of surface oxides with water, ... A Study on the Hot Corrosion Resistance of Metal-cemet-glass Coating onĀ...
A density functional theory study of the oxidation of methanol to formaldehyde over vanadia supported on silica, titania, and zirconia
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.
Khaliullin, Rustam Z.; Bell, Alexis T.
Oxidative degradation of bis (2,4,4-trimethylpentyl) dithiophosphinic acid in nitric acid studied by electrospray ionization mass spectrometry
Samples of bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex-301) were analyzed using direct infusion electrospray ionization mass spectrometry. Positive ion spectra of standard and stereo-pure acids displayed ions typical of the unmodified compound, cationized monomeric and dimeric cluster ion species. In addition, a significant ions 2 u less than the dimeric clusters were seen, that correspond to an oxidatively coupled species designated Cyx2 that is observed as H- or Na-cationized species in the electrospray analyses. Based on uncorrected ion intensities, Cyx2 is estimated to account for about 20% of the total in the standard materials. When samples that were contacted with 3 M HNO3 were analyzed, the positive ion spectrum consisted nearly entirely of ions derived from the oxidatively coupled product, indicating that the acid promotes coupling. The negative ion spectra of the standard acids consisted nearly entirely of the conjugate base that is formed by deprotonation of the acids, and cluster ions containing multiple acid molecules. The negative spectra of the HNO3-contacted samples also contained the conjugate base of the unmodified acid, but also two other species that correspond to the dioxo- and perthio- derivatives. It is concluded that HNO3 contact causes significant oxidation, forming at least three major products, Cyx2, the perthio-acid, and the dioxo-acid.
G. S. Groenewold; D. R. Peterman
An In-Situ XAS Study of the Structural Changes in a CuO-CeO2/Al2O3 Catalyst during Total Oxidation of Propane
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.
Silversmith, Geert; Poelman, Hilde; Poelman, Dirk; Gryse, Roger de [Ghent University, Department of Solid State Sciences, Krijgslaan 281 S1, B-9000 Gent (Belgium); Olea, Maria; Balcaen, Veerle; Heynderickx, Philippe; Marin, Guy B. [Ghent University, Laboratorium voor Petrochemische Techniek, Krijgslaan 281 S5, B-9000 Gent (Belgium)
Comparative study of the reactions of metal oxides and carbonates with H{sub 2}S and SO{sub 2}. Final technical report, September 1990--February 1994
The primary objective of this project had been the investigation of the effects of pore structure on the capacity of porous metal oxides for removal of gaseous pollutants from flue gases of power plants (SO{sub 2}) and hot coal gas (primarily H{sub 2}S). Porous calcines obtained from natural precursors (limestones and dolomites) and sorbents based on zinc oxide were used as model systems in our experimental studies, which included reactivity evolution experiments and pore structure characterization using a variety of methods. The key idea behind this project was to appropriately exploit the differences of the sulfidation and sulfation reactions (for instance, different molar volumes of solid products) to elucidate the dependence of the sorptive capacity of a porous sorbent on its physical microstructure. In order to be able to proceed faster and more productively on the analysis of the above defined problem, it was decided to employ in our studies solids whose reaction with SO{sub 2} (limestone calcines) or H{sub 2}S (sorbents based on zinc oxide) had been investigated in detail in past studies by our research group. Reactivity vs time or conversion vs time studies were conducted using thermogravimetry and fixed-bed and fluidized-bed reactors. The pore structure of partially reacted samples collected at selected time instants or conversion levels was analyzed by gas adsorption and mercury porosimetry. For better characterization of the pore structure of the solid samples, we also carried out intraparticle diffusivity measurements by the peak-broadening (chromatographic) method, using a system developed for this purpose in our laboratory. In the context of this part of the project, we also conducted a detailed theoretical investigation of the measurement of effective diffusivities in porous solids using the diffusion-cell method.
Sotirchos, S.V.
Laboratory Studies of Processing of Carbonaceous Aerosols by Atmospheric Oxidants/Hygroscopicity and CCN Activity of Secondary & Processed Primary Organic Aerosols
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 to carry out reactions of representative anthropogenic and biogenic VOCs and organic particles with ozone (O3), and hydroxyl (OH), nitrate (NO3), and chlorine (Cl) radicals, which are the major atmospheric oxidants, under simulated atmospheric conditions in large-volume environmental chambers. A combination of on-line and off-line analytical techniques were used to monitor the chemical and physical properties of the particles including their hygroscopicity and CCN activity. The results of the studies were used to (1) improve scientific understanding of the relationships between the chemical composition of organic particles and their hygroscopicity and CCN activity, (2) develop an improved molecular level theoretical framework for describing these relationships, and (3) establish a large database that is being used to develop parameterizations relating organic aerosol chemical properties and SOA sources to particle hygroscopicity and CCN activity for use in regional and global atmospheric air quality and climate models.
Ziemann, P.J.; Arey, J.; Atkinson, R.; Kreidenweis, S.M.; Petters, M.D.
Low and intermediate temperature oxidation of ethanol and ethanol-PRF blends: An experimental and modeling study
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)
Haas, Francis M.; Chaos, Marcos; Dryer, Frederick L. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)
CO Oxidation on supported single Pt atoms - Experimental and Ab Initio density functional studies of CO interaction with Pt atom on theta-alumina(010) surface
Although there are only a few known examples of supported single atoms, they are unique because they bridge the gap between homogenous and heterogeneous catalysis. The metal center is single supported atoms can be isoelectronic with their homogenous catalyst counterpart and may allow mechanistic pathways normally seen in homogenous catalysts. Here, we report CO oxidation activity of mono-disperse single Pt atoms supported on an inert substrate, -alumina (Al2O3), in the presence of stoichiometric oxygen. Since CO oxidation on single Pt atoms cannot occur via a conventional Langmuir-Hinshelwood scheme (L-H scheme) which requires at least one Pt-Pt bond, we have carried out a first principles density functional theoretical study of a proposed pathway which is a variation on the conventional L-H scheme and is inspired by organometallic chemistry of platinum. We find that a single supported Pt atom prefers to bond to O2 over CO. The CO then bonds with the oxygenated Pt atom and forms a carbonate which dissociates to liberate CO2, leaving an oxygen atom on Pt. A subsequent reaction with another CO molecule regenerates the single atom catalyst. An in-situ diffuse reflectance infrared study of CO adsorption on the catalyst s supported single atoms has been carried out to infer information on CO absorption modes and compare the observed spectra with calculated ones for intermediates in the proposed CO oxidation pathway. Our results clearly show that supported Pt single atoms are catalytically active and that this catalytic activity can occur without involving the substrate. Characterization by electron microscopy and X-ray absorption studies of the mono-disperse Pt/ -Al2O3, synthesized by solution methods, are also presented.
Narula, Chaitanya Kumar [ORNL; Debusk, Melanie Moses [ORNL; Yoon, Mina [ORNL; Allard Jr, Lawrence Frederick [ORNL; Mullins, David R [ORNL; Wu, Zili [ORNL; Yang, Xiaofan [ORNL; Veith, Gabriel M [ORNL; Stocks, George Malcolm [ORNL
Fischer-Tropsch synthesis: Moessbauer studies of pretreated ultrafine iron oxide catalysts. Partial quarterly progress report, April--June 1992
Chenshi Huang; Davis, B.H. [Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Research; Rao, K.R.P.M.; Huffman, G.P.; Huggins, F.E. [Kentucky Univ., Lexington, KY (United States). Inst. for Mining and Minerals Research
Study of hydrogen in coals, polymers, oxides, and muscle water by nuclear magnetic resonance; extension of solid-state high-resolution techniques. [Hydrogen molybdenum bronze
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.
Ryan, L.M.
Kinetics of Chromium(III) Oxidation by Manganese(IV) Oxides Using
. This represents the first study to determine the chemical kinetics of Cr(III) oxidation on Mn-oxides. The results focusing on the "chemical" kinetics of Cr(III) oxidation on manganese oxides, i.e., the initial rates of Obtaining and Analyzing Kinetic Data. In Rates of Soil Chemical Processes, Sparks, D. L., Suarez, D. L., Eds
Sparks, Donald L.
National Energy Technology Laboratory Publishes Solid Oxide Fuel...
Publications News Release Release Date: July 23, 2013 National Energy Technology Laboratory Publishes Solid Oxide Fuel Cell Studies SOFC Solid oxide fuel cells are among the...
Oxidation catalyst
DOE Patents (OSTI)
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.
Ceyer, Sylvia T. (Cambridge, MA); Lahr, David L. (Cambridge, MA)
Structural Properties Studies of Zinc Oxide Thin Film Grown on Silicon Carbide by Means of X-ray Diffraction Technique
In this work, the structural properties of the zinc oxide (ZnO) thin film on silicon carbide (6H-SiC) grown by radio frequency sputtering technique are investigated thoroughly by means of X-ray diffraction (XRD) technique. Both conventional XRD phase analysis and rocking curve measurements are carried out in order to determine the crystalline structure and the crystalline quality of the ZnO sample. From the phase analysis, intense peaks correspond to ZnO(002), iC(006) and their multiple reflections, i.e. ZnO(004) and SiC(0012) are observed. This result suggests that the ZnO thin film is in wurzite structure. Through the simulation of XRD rocking curve of the ZnO(002) peak, the lattice mismatch of 5.49% is obtained.
Ching, C. G.; Ng, S. S.; Hassan, Z.; Hassan, H. Abu; Al-Hardan, N. H.; Abdullah, M. J. [Nano-optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800, Penang (Malaysia)
Ni coarsening in the three-phase solid oxide fuel cell anode - a phase-field simulation study
Ni coarsening in Ni-yttria stabilized zirconia (YSZ) solid oxide fuel cell anodes is considered a major reason for anode degradation. We present a predictive, quantative modeling framework based on the phase-field approach to systematically examine coarsening kinetics in such anodes. The initial structures for simulations are experimentally acquired functional layers of anodes. Sample size effects and error analysis of contact angles are examined. Three phase boundary (TPB) lengths and Ni surface areas are quantatively identified on the basis of the active, dead-end, and isolated phase clusters throughout coarsening. Tortuosity evolution of the pores is also investigated. We find that phase clusters with larger characteristic length evolve slower than those with smaller length scales. As a result, coarsening has small positive effects on transport, and impacts less on the active Ni surface area than the total counter part. TPBs, however, are found to be sensitive to local morphological features and are only i...
Chen, Hsun-Yi; Cronin, J Scott; Wilson, James R; Barnett, Scott A; Thornton, Katsuyo
Nitric Acid Oxidized ZrO$_2$ as the Tunneling Oxide of Cobalt Silicide Nanocrystal Memory Devices
In this study, ZrO$_2$ formed by the nitric acid oxidation method is proposed to be the tunneling oxide for nonvolatile memory device applications. The sputtered Zr thin film was oxidized ...
Chih-Wei Hu; Ting-Chang Chang; Chun-Hao Tu; Yang-Dong Chen; Chao-Cheng Lin; Min-Chen Chen; Jian-Yang Lin; Simon M. Sze; Tseung-Yuen Tseng
Application of a nonisothermal thermogravimetric method to the kinetic study of the reduction of metallic oxides: Part 2. A theoretical treatment of powder bed reduction and its application to the reduction of tungsten oxide by hydrogen
Theoretical treatment of nonisothermal kinetic studies has been extended in the present work to gas-solid reactions in powder beds. An expression for the activation energies for the reaction has been derived on the basis that the reaction proceeds by the movement of the reaction front, the velocity of the movement being kept constant. The reliability of the method has been tested by applying the same to the reduction of tungsten oxide by hydrogen. The experiments were carried out using thermogravimetric technique under both isothermal and nonisothermal conditions. The reaction front is considered to consist of a thin layer of small particles. The rate of the reduction seems to be controlled by the chemical reaction between the product and the unreacted core existing in each of the small particles. Using the expression derived in the present work, the activation energy of the reaction was calculated from the results of the nonisothermal experiments to be 83.62 kJ/mol. This value is in good agreement with the value of 83.17 kJ/mol evaluated from isothermal experiments.
Bustnes, J.A.; Sichen, D.; Seetharaman, S. (Royal Inst. of Tech., Stockholm (Sweden). Department of Theoretical Metallurgy)
Thermally Oxidized Silicon
Anneli Munkholm (Lumileds Lighting) and Sean Brennan (SSRL) 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 lattice. The outline of four silicon unit cells is shown in black, whereas the outline of four expanded lattice cells in the oxide is shown in blue One of the most studied devices of modern technology is the field-effect transistor, which is the basis for most integrated circuits. At its heart
Kinetics of the sulfur oxidation on palladium: A combined in situ x-ray photoelectron spectroscopy and density-functional study
We studied the reaction kinetics of sulfur oxidation on the Pd(100) surface by in situ high resolution x-ray photoelectron spectroscopy and ab initio density functional calculations. Isothermal oxidation experiments were performed between 400 and 500 K for small amounts ({approx}0.02 ML) of preadsorbed sulfur, with oxygen in large excess. The main stable reaction intermediate found on the surface is SO{sub 4}, with SO{sub 2} and SO{sub 3} being only present in minor amounts. Density-functional calculations depict a reaction energy profile, which explains the sequential formation of SO{sub 2}, SO{sub 3}, and eventually SO{sub 4}, also highlighting that the in-plane formation of SO from S and O adatoms is the rate limiting step. From the experiments we determined the activation energy of the rate limiting step to be 85 {+-} 6 kJ mol{sup -1} by Arrhenius analysis, matching the calculated endothermicity of the SO formation.
Gotterbarm, Karin; Hoefert, Oliver; Lorenz, Michael P. A.; Streber, Regine; Papp, Christian [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Luckas, Nicola; Vines, Francesc [Lehrstuhl fuer Theoretische Chemie, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Steinrueck, Hans-Peter [Lehrstuhl fuer Physikalische Chemie II, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Erlangen Catalysis Resource Center (ECRC), Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Interdisciplinary Center for Interface Controlled Processes, Egerlandstr. 3, 91058 Erlangen (Germany); Goerling, Andreas [Lehrstuhl fuer Theoretische Chemie, Universitaet Erlangen-Nuernberg, Egerlandstr. 3, 91058 Erlangen (Germany); Interdisciplinary Center for Interface Controlled Processes, Egerlandstr. 3, 91058 Erlangen (Germany)
Compositional Analysis of the High Molecular Weight Ethylene Oxide Propylene Oxide Copolymer by MALDI Mass Spectrometry
The composition of narrow distribution poly ethylene oxide-propylene oxide copolymer (Mw ~ 8700 Da) was studied using matrix assisted laser desorption ionization (MALDI) mass spectrometry. The ethylene oxide-propylene oxide copolymer produced oligomers separated by 14 Da. The average resolving power over the entire spectrum was 28,000. Approximately 448 isotopically resolved peaks representing about 56 oligomers are identified. Although agreement between experimental and calculated isotopic distributions was strong, the compositional assignment was difficult. This is due to the large number of possible isobaric components. The purpose of this research is to resolve and study the composition of high mass copolymer such as ethylene oxide-propylene oxide.
Houshia, Orwa Jaber
Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, July 1, 1994--September 30, 1994
Research continued on the study of catalysts and membrane materials involved in the oxidative coupling of methane and coal gasification processes. Membranes studied and fabricated included Sr-Zr-Y-O, Sr-Zr-Y, and Sr-Ce-Y-O systems.
Iglesia, E.; Perry, D.L.; Heinemann, H.
Journal of Power Sources 153 (2006) 6875 Numerical study of a flat-tube high power density solid oxide fuel cell
for a solid oxide fuel cell (SOFC). This paper presents an examination of a simple hydrogen sulfide as a feedstock in a solid oxide fuel cell is discussed. A system configuration of an SOFC combined to the SOFC. The exhaust fuel gas of the SOFC is after-burned with exhaust air from the SOFC, and the heat
Lipid Oxidation Pathways
This book reviews state-of-the-art developments in the understanding of the oxidation of lipids and its connection with the oxidation of other biological molecules such as proteins and starch. Lipid Oxidation Pathways Hardback Books Health - Nutrition -
Transuranic decontamination of nitric acid solutions by the TRUEX solvent extraction process: preliminary development studies. [Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide
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.
Vandegrift, G.F.; Leonard, R.A.; Steindler, M.J.; Horwitz, E.P.; Basile, L.J.; Diamond, H.; Kalina, D.G.; Kaplan, L.
Enzymological and Structural Studies of the Mechanism of Promiscuous Substrate Recognition by the Oxidative DNA Repair Enzyme AlkB
Promiscuous substrate recognition, the ability to catalyze transformations of chemically diverse compounds, is an evolutionarily advantageous, but poorly understood phenomenon. The promiscuity of DNA repair enzymes is particularly important, because it enables diverse kinds of damage to different nucleotide bases to be repaired in a metabolically parsimonious manner. We present enzymological and crystallographic studies of the mechanisms underlying promiscuous substrate recognition by Escherichia coli AlkB, a DNA repair enzyme that removes methyl adducts and some larger alkylation lesions from endocyclic positions on purine and pyrimidine bases. In vitro Michaelis-Menten analyses on a series of alkylated bases show high activity in repairing N1-methyladenine (m1A) and N3-methylcytosine (m3C), comparatively low activity in repairing 1,N6-ethenoadenine, and no detectable activity in repairing N1-methylguanine or N3-methylthymine. AlkB has a substantially higher kcat and Km for m3C compared with m1A. Therefore, the enzyme maintains similar net activity on the chemically distinct substrates by increasing the turnover rate of the substrate with nominally lower affinity. Cocrystal structures provide insight into the structural basis of this 'kcat/Km compensation,' which makes a significant contribution to promiscuous substrate recognition by AlkB. In analyzing a large ensemble of crystal structures solved in the course of these studies, we observed 2 discrete global conformations of AlkB differing in the accessibility of a tunnel hypothesized to control diffusion of the O2 substrate into the active site. Steric interactions between a series of protein loops control this conformational transition and present a plausible mechanism for preventing O2 binding before nucleotide substrate binding.
Yu, B.; Hunt, J
Enzymes of respiratory iron oxidation
This report describes experimental progress in characterizing and identifying redox proteins in a number of iron-oxidizing bacteria. Sections of the paper are entitled (1) In Situ electrolysis was explored to achieve enhanced yields of iron-oxidizing bacteria, (2)Structure/function studies were performed on redox-active biomolecules from Thiobacillus ferrooxidans, (3) Novel redox-active biomolecules were demonstrated in other iron autotrophs, and (4) New probes of metalloprotein electron-transfer reactions were synthesized and characterized.
Blake, R. II.
Selective methane oxidation over promoted oxide catalysts
Objective was to selectively oxidize methane to C{sub 2} hydrocarbons and to oxygenates, in particular formaldehyde and methanol, in high space time yields under relatively mild reaction conditions. Results in this document are reported under the headings: methane oxidation over silica, methane oxidation over Sr/La{sub 2}O{sub 3} catalysts, and oxidative coupling of methane over sulfate-doped Sr/La{sub 2}O{sub 3} catalysts. 24 refs, 10 figs, 4 tabs.
Klier, K.; Herman, R.G.
A Modeling Study of Atmospheric Transport and Photochemistry in the Mixed Layer during Anticyclonic Episodes in Europe. Part II. Calculations of Photo-Oxidant Levels along Air Trajectories
A computer model for photochemical oxidant formation in the atmospheric boundary layer has been used to calculate trends in ozone formation in air masses traveling across Europe. Ozone calculations were made for some actual summertime ...
K. Selby
Photo-oxidation catalysts
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.
Pitts, J. Roland (Lakewood, CO); Liu, Ping (Irvine, CA); Smith, R. Davis (Golden, CO)
Carbon monoxide oxidation over three different states of copper: Development of a model metal oxide catalyst
Carbon monoxide oxidation was performed over the three different oxidation states of copper -- metallic (Cu), copper (I) oxide (Cu{sub 2}O), and copper (II) oxide (CuO) as a test case for developing a model metal oxide catalyst amenable to study by the methods of modern surface science and catalysis. Copper was deposited and oxidized on oxidized supports of aluminum, silicon, molybdenum, tantalum, stainless steel, and iron as well as on graphite. The catalytic activity was found to decrease with increasing oxidation state (Cu > Cu{sub 2}O > CuO) and the activation energy increased with increasing oxidation state (Cu, 9 kcal/mol < Cu{sub 2}O, 14 kcal/mol < CuO, 17 kcal/mol). Reaction mechanisms were determined for the different oxidation states. Lastly, NO reduction by CO was studied. A Cu and CuO catalyst were exposed to an equal mixture of CO and NO at 300--350 C to observe the production of N{sub 2} and CO{sub 2}. At the end of each reaction, the catalyst was found to be Cu{sub 2}O. There is a need to study the kinetics of this reaction over the different oxidation states of copper.
Jernigan, G.G. [California Univ., Berkeley, CA (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States). Materials and Chemical Sciences Div.
Mercury Oxidation Performance of Advanced SCR Catalyst
The ability of selective catalytic reduction (SCR) catalysts to oxidize mercury is an important aspect of many utilitiesÆ mercury control strategies. Improved SCR mercury oxidation will facilitate its capture in downstream wet¢flue gas desulfurization systems and will generally result in lower emission rates. Recently, catalyst manufacturers have attempted to maximize mercury oxidation through advanced catalyst formulations.This study documents the performance of an advanced ...
Multifunctional Oxides: Multifunctional Oxides: Synthesis and ...
Using Ultrafast Optical Spectroscopy to Explore Magneoelectric Coupling in Multiferroic Oxide Heterostructures: Y-M Sheu1; S. Trugman1; L Yan1; C-P Chuu 1;Ā...
A study of the kinetics and mechanism of the adsorption and anaerobic partial oxidation of n-butane over a vanadyl pyrophosphate catalyst
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{sub 2}O{sub 7} catalyst will not exist during this selective oxidation and that theories that relate selectivity in partial oxidation to the (100) face of the (VO){sub 2}P{sub 2}O{sub 7} catalyst cannot apply in this case.
Sakakini, B.H.; Taufiq-Yap, Y.H.; Waugh, K.C.
Functionalization of Graphene and Graphene Oxide for Biosensing and Imaging
Recent advances in our group about graphene biofunctionalization are discussed. In particular, the functionalization of graphene and graphene oxide, biosensing and bioimaging by using graphene-based nanomaterials, and some fundamental studies of graphene and graphene oxide have been summarized.
Li, Zhaohui; Wang, Ying; Du, Dan; Tang, Zhiwen; Wang, Jun; Lin, Yuehe
Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, 1 January--31 March 1994
This report describes work in progress on three tasks: (1) Catalytic steam gasification of coals and cokes; (2) Oxidative coupling of methane; and (3) Synthesis and characterization of catalysts. Since Task 1 is complete, a final report has been written. This report describes membrane reactors, cyclic methane conversion reactors, theoretical descriptions of reaction-separation schemes, and time-space relationships in cyclic and membrane reactors, all subtasks of Task 2. Initial studies under Task 3 are briefly described.
Iglesia, E.; Heinemann, H.; Perry, D.L. [Lawrence Berkeley Lab., CA (United States). Center for Advanced Materials
SOS public comments 76 fr 3877
... Interoperability Standards. Jordan, Tom. Laing, Patrick G. Layer 7 Technologies. Loud, James. Lumeta Inc. Maden Technologies. ...
National Energy Technology Laboratory Publishes Solid Oxide Fuel Cell
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
National Energy Technology Laboratory Publishes Solid Oxide Fuel National Energy Technology Laboratory Publishes Solid Oxide Fuel Cell Studies National Energy Technology Laboratory Publishes Solid Oxide Fuel Cell Studies July 23, 2013 - 1:07pm Addthis National Energy Technology Laboratory Publishes Solid Oxide Fuel Cell Studies What does this project do? For more information on DOE's efforts to make solid oxide fuel cells an efficient and economically compelling option, please visit: The NETL Solid Oxide Fuel Cells Program Webpage Solid oxide fuel cells are among the cleanest, most efficient power-generating technologies now being developed. They provide excellent electrical efficiencies and are capable of operating on a wide variety of fuels, from coal and natural gas to landfill waste and hydrogen. And with continued advancements, solid oxide fuel cells can provide clean
Structure and magnetic properties of the Al{sub 1-x}Ga{sub x}FeO{sub 3} family of oxides: A combined experimental and theoretical study
Magnetic properties of the Al{sub 1-x}Ga{sub x}FeO{sub 3} family of oxides crystallizing in a non-centrosymmetric space group have been investigated in detail along with structural aspects by employing X-ray and neutron diffraction, Moessbauer spectroscopy and other techniques. The study has revealed the occurrence of several interesting features related to unit cell parameters, site disorder and ionic size. Using first-principles density functional theory based calculations, we have attempted to understand how magnetic ordering and related properties in these oxides depend sensitively on disorder at the cation site. The origin and tendency of cations to disorder and the associated properties are traced to the local structure and ionic sizes. -- Graphical abstract: We have studied both experimentally and theoretically the important role of disorder at the cation site on magnetic and related properties of the Al{sub 1-x}Ga{sub x}FeO{sub 3} family of oxides crystallizing in a non-centrosymmetric space group. Display Omitted Research highlights: {yields} Interesting observations on cation site disorder, cell parameters and ionic size. {yields} Cation site disorder explains magnetic ordering. {yields} Demonstrates the importance of the A-site cations.
Saha, Rana; Shireen, Ajmala [Chemistry and Physics of Materials Unit, New Chemistry Unit, Theoretical Science Unit and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064 (India); Bera, A.K. [Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Shirodkar, Sharmila N.; Sundarayya, Y.; Kalarikkal, Nandakumar [Chemistry and Physics of Materials Unit, New Chemistry Unit, Theoretical Science Unit and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064 (India); Yusuf, S.M. [Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Waghmare, Umesh V. [Chemistry and Physics of Materials Unit, New Chemistry Unit, Theoretical Science Unit and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064 (India); Sundaresan, A., E-mail: firstname.lastname@example.com [Chemistry and Physics of Materials Unit, New Chemistry Unit, Theoretical Science Unit and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064 (India); Rao, C.N.R, E-mail: email@example.com [Chemistry and Physics of Materials Unit, New Chemistry Unit, Theoretical Science Unit and International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560 064 (India)
Solid oxide electrochemical reactor science.
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.
Sullivan, Neal P. (Colorado School of Mines, Golden, CO); Stechel, Ellen Beth; Moyer, Connor J. (Colorado School of Mines, Golden, CO); Ambrosini, Andrea; Key, Robert J. (Colorado School of Mines, Golden, CO)
Investigation of the Local Structure of Graphene Oxide
A study of the local structure of graphene oxide is presented. Graphene oxide is understood to be partially oxidized graphene. Absorption peaks corresponding to interlayer states suggest the presence of pristine graphitic nanoislands in graphene oxide. Site-projected partial density of states of carbon atoms bonded to oxygen atoms suggests that the broadening of the peak due to interlayer states in the carbon K-edge spectrum of graphene oxide is predominantly due to formation of epoxide linkages. Density functional theory suggests that multilayers of graphene oxide are linked by peroxide-like linkages.
S Saxena; T Tyson; E Negusse
Graphite Oxidation Thermodynamics/Reactions
The vulnerability of graphite-matrix spent nuclear fuel to oxidation by the ambient atmosphere if the fuel canister is breached was evaluated. Thermochemical and kinetic data over the anticipated range of storage temperatures (200 to 400 C) were used to calculate the times required for a total carbon mass loss of 1 mgcm-2 from a fuel specimen. At 200 C, the time required to produce even this small loss is large, 900,000 yr. However, at 400 C the time required is only 1.9 yr. The rate of oxidation at 200 C is negligible, and the rate even at 400 C is so small as to be of no practical consequence. Therefore, oxidation of the spent nuclear fuel upon a loss of canister integrity is not anticipated to be a concern based upon the results of this study.
Propp, W.A.
Oxidation pretreatment to reduce corrosion of 20%Cr-25%Ni-Nb stainless steel. II. Surface morphology and oxide characterization
Improved corrosion behavior of 20%Cr-25%Ni-Nb steel resulting from a low pressure oxidation pretreatment in CO/sub 2/ has been related to changes in elemental composition and distribution in the oxide scale. Auger electron spectroscopy, secondary ion mass spectroscopy, electron microprobe, and X-ray diffraction techniques have been used to investigate the properties of the oxide scale formed on both untreated and pretreated specimens when oxidized at 823 K and 923 K in a CO/sub 2/-1%CO atmosphere. A sputter ion plating technique has been used to separate the oxide from the metal and the incorporation of chromium and silicon at the metal-oxide interface has been investigated at grain centers and grain boundaries by depth profiling. The improvement in oxide adhesion and oxidation rates, using data from Parts I and II of this study, is assessed in terms of oxide formation by solid-state displacement reactions.
Tempest, P.A.; Wild, R.K.
Fundamentals of Mercury Oxidation in Flue Gas
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 using empirical approaches. To address this, rate constants for the entire 8-step homogeneous Hg oxidation sequence were developed using an internally consistent transition state approach. These rate constants when combined with the appropriate sub-mechanisms produced lower estimates of the overall extent of homogeneous oxidation, further suggesting that heterogeneous pathways play an important role in Hg oxidation in coal-fired systems.
JoAnn Lighty; Geoffrey Silcox; Constance Senior; Joseph Helble; Balaji Krishnakumar
Partial oxidation catalyst
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.
Krumpelt, Michael (Naperville, IL); Ahmed, Shabbir (Bolingbrook, IL); Kumar, Romesh (Naperville, IL); Doshi, Rajiv (Downers Grove, IL)
Hydrous metal oxide catalysts for oxidation of hydrocarbons
This report describes work performed at Sandia under a CRADA with Shell Development of Houston, Texas aimed at developing hydrous metal oxide (HMO) catalysts for oxidation of hydrocarbons. Autoxidation as well as selective oxidation of 1-octene was studied in the presence of HMO catalysts based on known oxidation catalysts. The desired reactions were the conversion of olefin to epoxides, alcohols, and ketones, HMOs seem to inhibit autoxidation reactions, perhaps by reacting with peroxides or radicals. Attempts to use HMOs and metal loaded HMOs as epoxidation catalysts were unsuccessful, although their utility for this reaction was not entirely ruled out. Likewise, alcohol formation from olefins in the presence of HMO catalysts was not achieved. However, this work led to the discovery that acidified HMOs can lead to carbocation reactions of hydrocarbons such as cracking. An HMO catalyst containing Rh and Cu that promotes the reaction of {alpha}-olefins with oxygen to form methyl ketones was identified. Although the activity of the catalyst is relatively low and isomerization reactions of the olefin simultaneously occur, results indicate that these problems may be addressed by eliminating mass transfer limitations. Other suggestions for improving the catalyst are also made. 57 refs.
Miller, J.E.; Dosch, R.G.; McLaughlin, L.I. [Sandia National Labs., Albuquerque, NM (United States). Process Research Dept.
Barium oxide, calcium oxide, magnesia, and alkali oxide free glass
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.
Lu, Peizhen Kathy; Mahapatra, Manoj Kumar
Multifunctional Oxide Heterostructures
This book is devoted to the rapidly developing field of oxide thin-films and heterostructures. Oxide materials combined with atomic-scale precision in a heterostructure exhibit an abundance of macroscopic physical properties involving the strong coupling between the electronic, spin, and structural degrees of freedom, and the interplay between magnetism, ferroelectricity, and conductivity. Recent advances in thin-film deposition and characterization techniques made possible the experimental realization of such oxide heterostructures, promising novel functionalities and device concepts.
Tsymbal, E Y [University of Nebraska, Lincoln; Dagotto, Elbio R [ORNL; Eom, Professor Chang-Beom [University of Wisconsin, Madison; Ramesh, Ramamoorthy [University of California, Berkeley
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.
Oxidation of gallium arsenide
This invention relates to gallium arsenide semiconductors and, more particularly, to the oxidation of surface layers of gallium arsenide semiconductors for semiconductor device fabrication.
Hoffbauer, M.A.; Cross, J.B.
Oct 28, 2009 ... International Symposium on Ceramic Matrix Composites: Oxidation/ ... on combustor liners of a Solar Turbines' industrial gas turbine engine,Ā...
Defect Structure of Oxides
Table 1┬Ā┬Ā┬ĀClassification of electrical conductors: oxides, sulfides, and nitrides...2 O 4 , NiAl 2 O 4 , (Tl 2 O),
Application of a nonisothermal thermogravimetric method to the kinetic study of the reduction of metallic oxides; Part 1. A general treatment and its application to the reduction of the oxides of molybdenum by hydrogen
In this paper a theoretical treatment to evaluate activation energies of reactions by means of nonisothermal experiments is developed. The treatment considers the case where either the surface reaction or the intraparticle diffusion could be rate-controlling. Complementary to the theoretical treatment, thermogravimetric experiments have been carried out under both isothermal and nonisothermal conditions. The reduction of MoO{sub 3} to Mo was found to pass through an intermediate MoO{sub 2} phase. The rate of reduction to MoO{sub 2} seems to be controlled by surface reaction, and the activation energy obtained from isothermal studies is 205.7 kJ/mol. This is comparable to the value of 211.6 kJ/mol obtained from nonisothermal reduction studies using the present theoretical treatment. The rate of reduction to Mo appears to be influenced by gas diffusion through voids. The activation energy from isothermal studies is 85.2 kJ/mol.
Sichen, D.; Seetharaman, S. (Dept. of Theoretical Metallurgy, Royal Inst. of Technology, S-100 44 Stockholm (SE))
Stabilized chromium oxide film
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.
Garwin, Edward L. (Los Altos, CA); Nyaiesh, Ali R. (Palo Alto, CA)
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.
Nyaiesh, A.R.; Garwin, E.L.
Nitric oxide reburning with methane
This paper deals with initial findings from the ongoing, three-year DOE program that began on 02/01/1995. The program involves computer simulation studies to aid in planning and conducting a series of experiments that will extend the knowledge of reburning process. The objective of this work is to find nitric oxide reduction effectiveness for various reburning fuels and identify both homogeneous and heterogeneous reaction mechanisms characterizing NO reduction.
Kumpaty, S.K. [Rust Coll., Holly Springs, MS (United States); Subramanian, K. [Subramanian (Kannikeswaran), Houston, TX (United States)
Initial stages of high temperature metal oxidation
The application of XPS and UPS to the study of the initial stages of high temperature (> 350/sup 0/C) electrochemical oxidation of iron and nickel is discussed. In the high temperature experiments, iron and nickel electrodes were electrochemically oxidized in contact with a solid oxide electrolyte in the uhv system. The great advantages of this technique are that the oxygen activity at the interface may be precisely controlled and the ability to run the reactions in uhv allows the simultaneous observation of the reactions by XPS.
Yang, C.Y.; O'Grady, W.E.
Active Zinc Oxide Production From Waste Zinc Powder
In this study, various quality of active zinc oxides containing up to 98 wt. ... Comparison of Microstructural Evolution of Nickel During Conventional and SparkĀ...
Computational Modeling of Oxidation and Corrosion of Alloys in ...
To address the kinetic effect, a multi-faceted modeling approach is being developed at NETL/DOE to study oxidation kinetics under different length scales.
Platinum Group Metal Oxide Absorption Properties of Perovskite ...
In this study, the absorption properties of various perovskite-type oxide is .... Influence of Different Cooling Structure on Surface Crack of HSLA Steel Plate by
Field Sites Power Marketing Administration Other Agencies You are here Home National Energy Technology Laboratory Publishes Solid Oxide Fuel Cell Studies National Energy...
Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, April 1, 1992--June 30, 1992
Work continued on the catalytic conversion of methane to produce C{sub 2}, C{sub 3},and C{sub 4} hydrocarbons. Progress is reported on the catalytic effects of Lithium Oxide and Magnesium Oxide catalysts.
Heinemann, H.; Somorjai, G.A.; Perry, D.L.
Electronic structure of graphene oxide and reduced graphene oxide monolayers
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.
Sutar, D. S. [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India); Central Surface Analytical Facility, Indian Institute of Technology Bombay, Mumbai 400076 (India); Singh, Gulbagh; Divakar Botcha, V. [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India)
Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, April 1, 1994--June 30, 1994
Catalytic gasification work has been completed and no other work is planned in the general area of catalytic gasification of coals and chars has operated without a post-doctoral fellow because of budget limitations during the first two quarters of FY1994. Dr. S. Sundararajan joined the group in April 1994 and will be assigned to the project throughout the remaining of the fiscal year. Results published by Hamakawa, et al. in The Journal of the Electrochemical Society have confirmed the concept of methane coupling via a membrane reactor. These findings confirm our previous conclusion that thinner membranes and increased surface activity for C-H bond activation at low temperatures are required in order to reach commercially attractive rates of reaction. The initial analysis of a theoretical model comparing the membrane and cyclic processes has been completed. The results indicate that perovskite membranes on the order of 50 microns will be needed for the membrane operation to be superior to a cyclic one. Two techniques, laser ablation and spin-coating/sol-gel chemistry are being tried to prepare the thin membranes described above. Studies of the magnetochemical properties of the calcium-nickel-potassium oxide powdered catalysts have been concluded and a manuscript describing the work has been completed. Synchrotron x-ray fluorescence microprobe data for calcium-nickel-potassium films have been analyzed and an abstract of the results has been submitted for presentation at the Fall Meeting of the Materials Research Society. Initial films of strontium-zirconium oxide, using yttria-stabilized zirconia as a buffer layer, have been fabricated using pulsed laser deposition. X-ray diffraction data have been obtained for several of the strontium-zirconium-yttrium oxide films.
Complete oxidation of methane on palladium catalysts. Final Report
This is the final report for grant DE-FG02-00ER15026. It summarizes all the accomplishments in these 8 sections: (1) Adaptations on Existing Unit and Construction of New Unit; (2) Turnover Rate and Reaction Orders for the Complete Oxidation of Methane on a Palladium Foil in Excess Dioxygen; (3) Surface area increase on Pd foils after oxidation in excess methane; (4) UV Raman spectroscopic study of hydrogen bonding in gibbsite and bayerite between 93 and 453 K; (5) Coverage of Palladium Catalysts by Oxidized Silicon During Complete Oxidation of Methane; (6) Kinetics of Methane Oxidation under lean conditions over Pd and PdO; (7) An Explanation for the Hysteresis on the Oxidation of Methane; and (8) Structure of Pd(111) after oxidation in O{sub 2}.
Ribeiro, Fabio H.
Oxidative Tritium Decontamination System
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.
Gentile, Charles A. (Plainsboro, NJ), Guttadora, Gregory L. (Highland Park, NJ), Parker, John J. (Medford, NJ)
Analysis of Lipid Oxidation
Analysis of Lipid Oxidation is essential for further developments in analytical methodology and hyphenated techniques, with which more understanding of the reaction kinetics, mechanism, and implications will take place. ...
Controlled CO preferential oxidation
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.
Meltser, M.A.; Hoch, M.M.
Metal atom oxidation laser
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)
Jensen, R.J.; Rice, W.W.; Beattie, W.H.
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.
The removal of recalcitrant sulfur species, dibenzothiophene and its derivatives, from automotive fuels is an integral component in the development of cleaner burning and more efficient automobile engines. Oxidative desulfurization (ODS) wherein the dibenzothiophene derivative is converted to its corresponding sulfoxide and sulfone is an attractive approach to sulfur removal because the oxidized species are easily extracted or precipitated and filtered from the hydrocarbon phase. Fe-TAML{reg_sign} activators of hydrogen peroxide (TAML is Tetra-Amido-Macrocyclic-Ligand) catalytically convert dibenzothiophene and its derivatives rapidly and effectively at moderate temperatures (50-60 C) and ambient pressure to the corresponding sulfoxides and sulfones. The oxidation process can be performed in both aqueous systems containing alcohols such as methanol, ethanol, or t-butanol, and in a two-phase hydrocarbon/aqueous system containing tert-butanol or acetonitrile. In the biphasic system, essentially complete conversion of the DBT to its oxidized products can be achieved using slightly longer reaction times than in homogeneous solution. Among the key features of the technology are the mild reaction conditions, the very high selectivity where no over oxidation of the sulfur compounds occurs, the near stoichiometric use of hydrogen peroxide, the apparent lack of degradation of sensitive fuel components, and the ease of separation of oxidized products.
Dr. Colin P. Horwitz; Dr. Terrence J. Collins
Thermal-fluid and electrochemical modeling and performance study of a planar solid oxide electrolysis cell : analysis on SOEC resistances, size, and inlet flow conditions.
Argonne National Laboratory and Idaho National Laboratory researchers are analyzing the electrochemical and thermal-fluid behavior of solid oxide electrolysis cells (SOECs) for high temperature steam electrolysis using computational fluid dynamics (CFD) techniques. The major challenges facing commercialization of steam electrolysis technology are related to efficiency, cost, and durability of the SOECs. The goal of this effort is to guide the design and optimization of performance for high temperature electrolysis (HTE) systems. An SOEC module developed by FLUENT Inc. as part of their general CFD code was used for the SOEC analysis by INL. ANL has developed an independent SOEC model that combines the governing electrochemical mechanisms based on first principals to the heat transfer and fluid dynamics in the operation of SOECs. The ANL model was embedded into the commercial STAR-CD CFD software, and is being used for the analysis of SOECs by ANL. The FY06 analysis performed by ANL and reported here covered the influence of electrochemical properties, SOEC component resistances and their contributing factors, SOEC size and inlet flow conditions, and SOEC flow configurations on the efficiency and expected durability of these systems. Some of the important findings from the ANL analysis are: (1) Increasing the inlet mass flux while going to larger cells can be a compromise to overcome increasing thermal and current density gradients while increasing the cell size. This approach could be beneficial for the economics of the SOECs; (2) The presence of excess hydrogen at the SOEC inlet to avoid Ni degradation can result in a sizeable decrease in the process efficiency; (3) A parallel-flow geometry for SOEC operation (if such a thing be achieved without sealing problems) yields smaller temperature gradients and current density gradients across the cell, which is favorable for the durability of the cells; (4) Contact resistances can significantly influence the total cell resistance and cell temperatures over a large range of operating potentials. Thus it is important to identify and avoid SOEC stack conditions leading to such high resistances due to poor contacts.
Yildiz, B.; Smith, J.; Sofu, T.; Nuclear Engineering Division
The burnup dependence of light water reactor spent fuel oxidation
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 associated with spent fuel oxidation (Section 5).
Hanson, B.D.
Atomistic modeling of ultra-thin surface oxide growth on a ternary alloy : oxidation of Al-Ni-Fe.
By employing variable-charge molecular dynamics, surface oxide film growth on aluminum-nickel-iron alloys has been studied at 300 and 600 K. The dynamics of oxidation and oxide growth is strongly dependent on the composition of the initial alloy and the ambient temperature. Higher content of Ni and Fe in Al alloys is found to reduce the oxide growth kinetics; 15% Ni + 15% Fe Al alloy yielded 30-40% less growth at 400 ps oxygen exposure compared to pure Al. We observe dopant segregation, which disrupts the interaction between O atoms and Al atoms in the alloy, leading to a nonlinear oxide growth profile in the case of ternary Al-Ni-Fe alloy. Compared to oxidation at 300 K, 30% more oxide layer was yielded at 600 K, due to the elevated temperature. The simulated oxide kinetics indicates that the growth rate of anion surpasses the cation rate with higher sensitivity to the stoichiometry of the base metal substrate. Charge state analysis provides insights into the evolution of cation and anion species as the oxide layer grows. In particular, due to higher correlation, Fe shows a high rate of oxidation when the content is high, whereas the rate of Ni oxidation is consistently low. Density profile analysis suggests the segregation of dopant atoms below the growing ultrathin oxide layer, showing the presence of a layer-by-layer mode of oxide layer even with disordered structure. Coordination number (Z, the number of oxygen atoms around an aluminum atom) of aluminum oxide has been used to identify how the initial oxidation transitions into equilibrated states. Z = 3 is dominant in the early stages of oxidation and at the interface between oxide and bulk substrate, but it transitions quickly to Z = 4 (45%) and 5 (35%) as the oxide equilibrates and approaches its self-limiting thickness. Even though growth kinetics is dependent on the base metal stoichiometry, the composition of the oxide microstructure is not significantly affected, primarily segregating dopant elements, i.e., Ni and Fe outside of the oxide layer.
Byoungseon, J.; Sankaranarayanan, S. K. R. S.; Ramanathan, S. (Center for Nanoscale Materials); (Harvard Univ.)
Methanol partial oxidation reformer
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.
Ahmed, S.; Kumar, R.; Krumpelt, M.
Molecular water oxidation catalyst
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.
Gratzel, Michael (St. Sulpice, CH); Munavalli, Shekhar (Bel Air, MD); Pern, Fu-Jann (Lakewood, CO); Frank, Arthur J. (Lakewood, CO)
Tetraalykylammonium polyoxoanionic oxidation catalysts
Alkanes are catalytically oxidized in air or oxygen using iron-substituted polyoxoanions (POAs) of the formula: H.sub.e-z ø(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.
Ellis, Paul E. (Downingtown, PA); Lyons, James E. (Wallingford, PA); Myers, Jr., Harry K. (Cochranville, PA); Shaikh, Shahid N. (Media, PA)
Tetraalklylammonium polyoxoanionic oxidation catalysts
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.
Ellis, P.E.; Lyons, J.E.; Myers, H.K. Jr.; Shaikh, S.N.
Looking at Transistor Gate Oxide Formation in Real Time
Looking at Transistor Gate Oxide Formation in Real Time Print Looking at Transistor Gate Oxide Formation in Real Time Print The oxide gate layer is critical to every transistor, and present-day layer thicknesses are in the 10-20 ├ģ 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 high-vacuum conditions. Now, for the first time, a group of researchers has obtained real-time oxidation results for this elusive range. Using the ambient-pressure x-ray photoelectron spectroscopy (APXPS) endstation at ALS Beamline 9.3.2, they examined oxidation of Si(100) at pressures up to 1 torr and temperatures up to 450 ┬║C. The Si 2p chemical shifts allowed determination of oxide thickness as a function of time with a precision of 1-2 ├ģ. The initial oxidation rate was very high (up to ~234 ├ģ/h). Then, after an initial oxide thickness of 6-22 ├ģ was formed, the rate decreased markedly (~1.5-4.0├ģ/h). Neither rate regime can be explained by the standard Deal-Grove (D-G) model for Si oxidation. These results are a significant step toward developing a better understanding of this critical thickness regime.
Dissolving uranium oxide--aluminum fuel
The dissolution of aluminum-clad uranium oxide-aluminum fuel was studied to provide basic data for dissolving this type of enriched uranium fuel at the Savannah River Plant. The studies also included the dissolution of a similar material prepared from scrap uranium oxides that were to be recycled through the solvent extraction process. The dissolving behavior of uranium oxide-aluminum core material is similar to that of U-Al alloy. Dissolving rates are rapid in HNO/sub 3/-Hg(NO/sub 3/)/sub 2/ solutions. Irradiation reduce s the dissolving rate and increases mechanical strength. A dissolution model for use in nuclear safety analyses is developed, . based on the observed dissolving characteristics. (auth)
Perkins, W.C.
Biological Properties of Zinc Oxide-Coated Anodized Aluminum Oxide
We used agar diffusion assays to evaluate the activity of zinc oxide-coated ... Zirconia Stabilisation Nano-Confined by Using Electroless Nickel Cladding .... Metal Oxide Nanofibers Produced by a ForceSpinning Method for Battery Electrodes.
Economics of nuclear fuel cycles : option valuation and neutronics simulation of mixed oxide fuels
In most studies aiming at the economic assessment of nuclear fuel cycles, a primary concern is to keep scenarios economically comparable. For Uranium Oxide (UOX) and Mixed Oxide (MOX) fuels, a traditional way to achieve ...
De Roo, Guillaume
Investigation of the nature of electronic states in the alkali_metal oxides
Hartree-Fock and Density functional theories have been applied to investigate the density of electronic states and electronic band structures. We studied: oxides, peroxides, nadoxides and ozonides, alkali-metal oxides M2O, peroxides M2O2, ...
O. O. Obolonskaya
Size Effect of Ruthenium Nanoparticles in Catalytic Carbon Monoxide Oxidation
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.
Joo, Sang Hoon; Park, Jeong Y.; Renzas, J. Russell; Butcher, Derek R.; Huang, Wenyu; Somorjai, Gabor A.
Doped zinc oxide microspheres
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.
Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.
Highly oxidized superconductors
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.
Morris, D.E.
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.
Morris, Donald E. (Kensington, CA)
Hydrous oxide activated charcoal
This patent describes a process for preparing of an ion exchanger, comprising: treating an ionically inert activated charcoal porous support with an aqueous solution of metal oxychloride selected from the group consisting of zirconium and titanium oxychlorides so as to impregnate the pores of the support with the solution; separating the treated support from excess metal oxychloride solution; converting the metal oxychloride to a hydrous metal oxide precipitate in the pores of the support at a pH above 8 and above the pH whereat the hydrous metal oxide and activated charcoal support have opposite zeta potentials and sufficient to hydrolyze the metal oxychloride. It also describes a process for preparing an ion exchanger comprising: treating granulated activated charcoal with a concentrated solution of a metal oxychloride from the group consisting of zirconium and titanium oxychlorides, degassing the mixture; and treating the resultant mixture with a base selected from the group consisting of ammonium hydroxide and alkali metal hydroxides so as to precipitate the oxychloride within the pores of the activated carbon granules as hydrous metal oxide at a pH above 8 and above the pH whereat the hydrous metal oxide and activated charcoal have opposite zeta potentials.
Weller, J.P.
Low temperature plasma enhanced chemical vapor deposition of silicon oxide films using disilane and nitrous oxide
Keywords: disilane, low temperature, nitrous oxide, plasma enhanced chemical vapor deposition, silicon oxide
Juho Song; G. S. Lee; P. K. Ajmera
Oxygen sensitive, refractory oxide composition
Oxide compositions containing niobium pentoxide and an oxide selected from the group consisting of hafnia, titania, and zirconia have electrical conductivity characteristics which vary greatly depending on the oxygen content.
Holcombe, Jr., Cressie E. (Oak Ridge, TN); Smith, Douglas D. (Knoxville, TN)
Cholesterol and Phytosterol Oxidation Products
This book comprehensively reviews several aspects of cholesterol oxidation products: cholesterol oxidation mechanisms, analytical determination, origin and content of these compounds in foods and biological samples, and their biological effects, with an em
Lipid Oxidation Pathways, Volume 2
This book complements Lipid Oxidation Pathways, Volume 1. Lipid Oxidation Pathways, Volume 2 Health acid analysis aocs april articles chloropropanediol contaminants detergents dietary fats division divisions esters fats fatty food foods glycidol Health h
Kinetics and dynamics of oxidation reactions involving an adsorbed CO species on bulk and supported platinum and copper-oxide
The proposed research is an integrated experimental and modeling study of oxidation reactions involving CO as a key player -- be it a reactant, adsorbed intermediate, and/or partial oxidation product -- in the catalytic sequence and chemistry. The reaction systems of interest in the project include CO, formaldehyde, and methanol oxidation by O{sub 2} and CO oxidation by NO, on both Pt and copper oxide catalysts. These reactions are of importance in automobile exhaust catalysis. There is a paucity of rate data in the literature for these important environmental control reactions. The goal of this research is to better understand the catalytic chemistry and kinetics of oxidations reactions involving CO as an adsorbed intermediate. Successfully meeting this goal requires an integration of basic kinetic measurements, in situ catalyst surface monitoring, kinetic modeling, and nonlinear mathematical tools.
Harold, M.P.
The design of new, high efficiency and cleaner burning engines is strongly coupled with the removal of recalcitrant sulfur species, dibenzothiophene and its derivatives, from fuels. Oxidative desulfurization (ODS) wherein these dibenzothiophene derivatives are oxidized to their corresponding sulfoxides and sulfones is an approach that has gained significant attention. Fe-TAML{reg_sign} activators of hydrogen peroxide (TAML is Tetra-Amido-Macrocyclic-Ligand) convert in a catalytic process dibenzothiophene and its derivatives to the corresponding sulfoxides and sulfones rapidly at moderate temperatures (60 C) and ambient pressure. The reaction can be performed in both an aqueous system containing an alcohol (methanol, ethanol, or t-butanol) to solubilize the DBT and in a two-phase hydrocarbon/aqueous system where the alcohol is present in both phases and facilitates the oxidation. Under a consistent set of conditions using the FeBF{sub 2} TAML activator, the degree of conversion was found to be t-butanol > methanol > ethanol. In the cases of methanol and ethanol, both the sulfoxide and sulfone were observed while for t-butanol only the sulfone was detected. In the two-phase system, the alcohol may function as an inverse phase transfer agent. The oxidation was carried out using two different TAML activators. In homogeneous solution, approximately 90% oxidation of the DBT could be achieved using the prototype TAML activator, FeB*, by sonicating the solution at near room temperature. In bi-phasic systems conversions as high as 50% were achieved using the FeB* TAML activator and hydrogen peroxide at 100 C. The sonication method yielded only {approx}6% conversion but this may have been due to mixing.
Colin P. Horwitz; Terrence J. Collins
Superior catalysts for selective catalytic reduction of nitric oxide. Quarterly technical progress report, January 1, 1995--March 31, 1995
During this quarter, progress was made on the following tasks: TPD techniques were employed to study the reaction mechanism of the selective catalytic reduction of nitrogen oxide with ammonia over iron oxide pillared clay catalyst; and a sulfur dioxide resistant iron oxide/titanium oxide catalyst was developed.
Li, W.B.; Yang, R.T.
A brief review of plutonium oxidation literature was conducted. The purpose of the review was to ascertain the effect of oxidation conditions on oxide morphology to support the design and operation of the PDCF direct metal oxidation (DMO) furnace. The interest in the review was due to a new furnace design that resulted in oxide characteristics that are different than those of the original furnace. Very little of the published literature is directly relevant to the DMO furnace operation, which makes assimilation of the literature data with operating conditions and data a convoluted task. The oxidation behavior can be distilled into three regimes, a low temperature regime (RT to 350 C) with a relatively slow oxidation rate that is influenced by moisture, a moderate temperature regime (350-450 C) that is temperature dependent and relies on more or less conventional oxidation growth of a partially protective oxide scale, and high temperature oxidation (> 500 C) where the metal autocatalytically combusts and oxidizes. The particle sizes obtained from these three regimes vary with the finest being from the lowest temperature. It is surmised that the slow growth rate permits significant stress levels to be achieved that help break up the oxides. The intermediate temperatures result in a fairly compact scale that is partially protective and that grows to critical thickness prior to fracturing. The growth rate in this regime may be parabolic or paralinear, depending on the oxidation time and consequently the oxide thickness. The high temperature oxidation is invariant in quiescent or nearly quiescent conditions due to gas blanketing while it accelerates with temperature under flowing conditions. The oxide morphology will generally consist of fine particles ( 250 {micro}m). The particle size ratio is expected to be < 5%, 25%, and 70% for fine, medium and large particles, respectively, for metal temperatures in the 500-600 C range.
Korinko, P.
A brief review of plutonium oxidation literature was conducted. The purpose of the review was to ascertain the effect of oxidation conditions on oxide morphology to support the design and operation of the PDCF direct metal oxidation (DMO) furnace. The interest in the review was due to a new furnace design that resulted in oxide characteristics that are different than those of the original furnace. Very little of the published literature is directly relevant to the DMO furnace operation, which makes assimilation of the literature data with operating conditions and data a convoluted task. The oxidation behavior can be distilled into three regimes, a low temperature regime (RT to 350 C) with a relatively slow oxidation rate that is influenced by moisture, a moderate temperature regime (350-450 C) that is temperature dependent and relies on more or less conventional oxidation growth of a partially protective oxide scale, and high temperature oxidation (> 500 C) where the metal autocatalytically combusts and oxidizes. The particle sizes obtained from these three regimes vary with the finest being from the lowest temperature. It is surmised that the slow growth rate permits significant stress levels to be achieved that help break up the oxides. The intermediate temperatures result in a fairly compact scale that is partially protective and that grows to critical thickness prior to fracturing. The growth rate in this regime may be parabolic or paralinear, depending on the oxidation time and consequently the oxide thickness. The high temperature oxidation is invariant in quiescent or nearly quiescent conditions due to gas blanketing while it accelerates with temperature under flowing conditions. The oxide morphology will generally consist of fine particles (<15 {micro}m), moderately sized particles (15 < x < 250 {micro}m) and large particles (> 250 {micro}m). The particle size ratio is expected to be < 5%, 25%, and 70% for fine, medium and large particles, respectively, for metal temperatures in the 500-600 C range.
Multifunctional Oxide - Programmaster.org
Toshihiko Tani, Toyota Motor Engineering and Manufacturing North America, Inc. Scope, Multifunctional oxide ceramics and thin films exhibit fascinatingĀ...
Surface modeling of thin film growth: A study of silicon oxide deposition from tetraethoxysilane and silicon deposition from disilane on the Si(100) surface
In this thesis, surface reactions brought about by the pyrolysis of adsorbed TEOS, the modeling of this reaction with ethanol, and the photolysis of adsorbed disilane have been investigated under ultrahigh vacuum conditions, using mainly temperature programmed desorption (TPD). TEOS molecularly desorbs at about 195K when adsorbed on clean Si(100) at low temperatures. When adsorbed at 300K, the primary surface species produced is a mixture of ethoxysiloxanes. Upon heating the surface in vacuum, the adsorbed ethoxysiloxanes decompose the evolve ethylene and hydrogen, with trace production of acetylene and acetaldehyde. In a parallel study, the adsorption and subsequent deposition of ethanol (C[sub 2]H[sub 5]OH, C[sub 2]D[sub 5]OD, and CH[sub 3]CD[sub 2]OH) on Si(100) has been shown to model the TEOS system. The molecular desorption temperature is ca. 150K. When adsorbed at 200K, ethanol dissociatively chemisorbs as an ethoxide and the monohydride species. The adlayer decomposes at higher temperature to evolve ethylene, hydrogen, acetaldehyde, and acetylene. The adsorption and decomposition of ethanol on Si(100)-2x1:H has also been studied in gathering additional information about the competition between distinct decomposition mechanisms, and the nature of the reaction site. In the Si[sub 2]H[sub 6]/Si(100) system, with no UV irradiation, disilane adsorption at 120K produces a chemisorbed SiH[sub x] (x = 1 - 3) layer and, for high exposures, a disilane multilayer. Upon heating the surface in vacuum, molecular desorption is observed at ca. 150K, while hydrogen and silane are evolved at much higher temperatures. For Si[sub 2]H[sub 6] exposure during photo-irradiation, the desorption yields of hydrogen and silane are enhanced. Model studies using the partially and fully deuterated Si(100)-2x1:D surface reveals that the photo-induced surface reaction is dominated by an insertion reaction by the photo-generated silylene species.
Cho, Hee-Chuen.
CO oxidation on substituted copper chromite spinel oxide catalysts
Oxidation of carbon monoxide was studied on Mg- and Al-substituted CuCr[sub 2]O[sub 4] spinel catalyst at atmospheric pressure and temperatures between 373 and 723 K. The activity of CuCr[sub 2]O[sub 4] decreased even for small replacements of either Cu by Mg or Cr by Al and none of the substituted oxides was as active as CuCr[sub 2]O[sub 4]. In Cu[sub 1[minus]x]Mg[sub x]Cr[sub 2]O[sub 4] catalysts, the activity systematically decreased with increasing x, except for 0.4 < x < 0.6. The decrease in activity is due to a decrease in the active Cu[sup 2+] ions of the catalyst. The increase in activity on increasing x from 0.4 to 0.6 is attributed to the crystallographic phase change, i.e., tetragonal to cubic, in the catalyst. This was also found in the CuCr[sub 2[minus]x]Al[sub x]O[sub 4] catalysts. The decrease in the catalytic activity on substitution of Cr by Al, even when the total copper content is not altered, is due to the reduction of some of the active Cu[sup 2+] ions to Cu[sup 1+] ions. 10 refs., 9 figs., 2 tabs.
Murthy, K.S.R.C. (Indian Telephone Industries, Ltd., Banglore (India)); Ghose, J. (Indian Institute of Technology, Kharagpur (India))
Impact Dynamics of Oxidized Liquid Metal Drops
With exposure to air, many liquid metals spontaneously generate an oxide layer on their surface. In oscillatory rheological tests, this skin is found to introduce a yield stress that typically dominates the elastic response but can be tuned by exposing the metal to hydrochloric acid solutions of different concentration. We systematically studied the normal impact of eutectic gallium-indium (eGaIn) drops under different oxidation conditions and show how this leads to two different dynamical regimes. At low impact velocity (or low Weber number), eGaIn droplets display strong recoil and rebound from the impacted surface when the oxide layer is removed. In addition, the degree of drop deformation or spreading during the impact is controlled by the oxide skin. We show that the scaling law known from ordinary liquids for the maximum spreading radius as a function of impact velocity can still be applied to the case of oxidized eGaIn if an effective Weber number $We^{\\star}$ is employed that uses an effective surface...
Xu, Qin; Jaeger, Heinrich M
The Interaction of Dissolved H with Internally Oxidized Pd-Rh Alloys
Binary Pd-M alloys containing small amounts of readily oxidizable solute metals such as M equals Al, Mg, or Zr, can be internally oxidized to form essentially pure Pd matrices containing a second phase of nano-sized oxide precipitates. During internal oxidation Pd atoms are transported to the surface forming Pd nodules while vacancies are transported from the surface to the metal/oxide interface relieving the compressive stress which develops within the alloy due to the expanding metal oxide precipitates. The Pd alloys that have been studied contain that form very stable oxides.
Shanahan, K.L.
A Kinetic Modeling study on the Oxidation of Primary Reference Fuel?Toluene Mixtures Including Cross Reactions between Aromatics and Aliphatics
A detailed chemical kinetic model for the mixtures of Primary Reference Fuel (PRF: n-heptane and iso-octane) and toluene has been proposed. This model is divided into three parts; a PRF mechanism [T. Ogura et al., Energy & Fuels 21 (2007) 3233-3239], toluene sub-mechanism and cross reactions between PRF and toluene. Toluene sub-mechanism includes the low temperature kinetics relevant to engine conditions. A chemical kinetic mechanism proposed by Pitz et al. [Proc. the 2nd Joint Meeting of the U.S. Combust. Institute (2001)] was used as a starting model and modified by updating rate coefficients. Theoretical estimations of rate coefficients were performed for toluene and benzyl radical reactions important at low temperatures. Cross-reactions between alkane, alkene, and aromatics were also included in order to account for the acceleration by the addition of toluene into iso-octane recently found in the shock tube study of the ignition delay [Y. Sakai et al, SAE 2007-01-4014 (2007)]. Validations of the model were performed with existing shock tube and flow tube data. The model well predicts the ignition characteristics of toluene and PRF/Toluene mixtures under the wide range of temperatures (500-1700 K) and pressures (2-50 atm). It is found that reactions of benzyl radical with oxygen molecule determine the reactivity of toluene at low temperature. Although the effect of toluene addition to iso-octane is not fully resolved, the reactions of alkene with benzyl radical have the possibility to account for the kinetic interactions between PRF and toluene.
Sakai, Y; Miyoshi, A; Koshi, M; Pitz, W J
Oxides for Spintronics - Programmaster.org
About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Multifunctional Oxides. Presentation Title, Oxides for Spintronics. Author(s)Ā...
Compositions and methods of making are provided for mesoporous metal oxide microspheres electrodes. The mesoporous metal oxide microsphere ...
Principal accomplishments have been achieved in all three areas of selective catalytic oxidation of methane that have been pursued in this research project. These accomplishments are centered on the development of catalyst systems that produce high space time yields of C{sub 2} hydrocarbon products, formaldehyde, and methanol from methane/air mixtures at moderate temperatures and at ambient pressure. The accomplishments can be summarized as the following: the SO{sub 4}{sup 2{minus}}/SrO/La{sub 2}O{sub 3} catalyst developed here has been further optimized to produce 2 kg of C{sub 2} hydrocarbons/kg catalyst/hr at 550C; V{sub 2}O{sub 5}SiO{sub 2} catalysts have been prepared that produce up to 1.5 kg formaldehyde/kg catalyst/hr at 630C with CO{sub 2} selectivities; and a novel dual bed catalyst system has been designed and tested that produces over 100 g methanol/kg catalyst/hr at 600C.
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.
Meltser, Mark A. (Pittsford, NY); Hoch, Martin M. (Webster, NY)
Applications of Oxide Superconductors
The discovery of the new family of copper-oxide superconductors has opened an area of exciting new materials science with enormous potential for practical developments in technology and engineering. Research was conducted to understand the basic physical properties and the materials characteristics of the high temperature superconductors that control their electrical and mechanical properties, and determine their potential usefulness. Material properties and current carrying capabilites of the new Bismut...
Chemical oxidizers treat wastewater
Based on the inherent benefits of these original oxidation systems, a second generation of advanced oxidation processes (AOPs) has emerged. These processes combine key features of the first generation technologies with more sophisticated advances in UV technology, such as the new pulsed plasma xenon flash lamp that emits high-energy, high-intensity UV light. Second generation systems can be equipped with a transmittance controller to prevent lamp fouling or scaling. The coupling of the first generation's technology with the new UV sources provides the rapid destruction of chlorinated and nonchlorinated hydrocarbons and humic acids from contaminated water. It also is effective in the treatment of organic laden gases from soil vapor extraction systems. AOPs may promote the oxidation (and subsequent removal) of heavy metals in water, though few data are available to verify the claim. The success of AOPs, including ozonation with UV light, hydrogen peroxide with UV light and advanced photolysis, is linked with their creation of hydroxyl-free radicals (OH[center dot]) that are effective in eliminating contaminants such as formaldehyde, chlorinated hydrocarbons and chlorinated solvents. Hydroxyl free-radicals are consumed in microsecond reactions and exhibit little substrate selectivity with the exception of halogenated alkanes such as chloroform. They can act as chain carriers. Given their power, hydroxyl free-radicals react with virtually all organic solutes more quickly (especially in water) than any other oxidants, except fluorine. There are projects that have found the combination of some AOPs to be the most efficient organic destruction techniques for the job. For example, one project successfully remediated groundwater contaminated with gasoline and Number 2 diesel through successive treatments of ozone and hydrogen peroxide with ultraviolet light, followed by granular activated carbon. 5 refs., 2 tabs.
Stephenson, F.A. (Dames Moore, Phoenix, AZ (United States))
Kinetics and mechanism of the oxidation of alkenes and silanes by hydrogen peroxide catalyzed by methylrhenium trioxide (MTO) and a novel application of electrospray mass spectrometry to study the hydrolysis of MTO
Conjugated dienes were oxidized by hydrogen peroxide with methylrhenium trioxide (MTO) as catalyst. Methylrhenium bis-peroxide was the major reactive catalyst present. Hydroxyalkenes and trisubstituted silane were also tested. Mechanisms for each of these reactions are presented.
Tan, Haisong
Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, October 1, 1994--December 31, 1994
This report describes research on the oxidative coupling of methane and catalysts involved in coal gasification. Topics include methane pyrolysis and catalysts, and magnetic properties of the coal gasification catalyst Ca-Ni-K-O system.
Advanced materials for solid oxide fuel cells: Hafnium-Praseodymium-Indium Oxide System
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.
Bates, J.L.; Griffin, C.W.; Weber, W.J.
Solid Oxide Fuel Cells
Solid oxide fuel cell (SOFC) technology, which offers many advantages over traditional energy conversion systems including low emission and high efficiency, has become increasingly attractive to the utility, automotive, and defense industries (as shown in Figure 1). As an all solid-state energy conversion device, the SOFC operates at high temperatures (700-1,000 C) and produces electricity by electrochemically combining the fuel and oxidant gases across an ionically conducting oxide membrane. To build up a useful voltage, a number of cells or PENs (Positive cathode-Electrolyte-Negative anode) are electrically connected in series in a stack through bi-polar plates, also known as interconnects. Shown in Figure 2 (a) is a schematic of the repeat unit for a planar stack, which is expected to be a mechanically robust, high power-density and cost-effective design. In the stack (refer to Figure 2 (b)), the interconnect is simultaneously exposed to both an oxidizing (air) environment on the cathode side and a reducing (fuels such as hydrogen or natural gas) environment on the anode side for thousands of hours at elevated temperatures (700-1,000 C). Other challenges include the fact that water vapor is likely to be present in both of these environments, and the fuel is likely to contain sulfide impurities. Also, the interconnect must be stable towards any sealing materials with which it is in contact, under numerous thermal cycles. Furthermore, the interconnect must also be stable towards electrical contact materials that are employed to minimize interfacial contact resistance, and/or the electrode materials. Considering these service environments, the interconnect materials should possess the following properties: (1) Good surface stability (resistance to oxidation and corrosion) in both cathodic (oxidizing) and anodic (reducing) atmospheres. (2) Thermal expansion matching to the ceramic PEN and other adjacent components, all of which typically have a coefficient of thermal expansion (CTE) in the range of 10.5-12.0 x 10{sup -6} K{sup -1}. (3) High electrical conductivity through both the bulk material and in-situ formed oxide scales. (4) Satisfactory bulk and interfacial mechanical/thermomechanical reliability and durability at the SOFC operating temperatures. (5) Good compatibility with other materials in contact with interconnects such as seals and electrical contact materials. Until recently, the leading candidate material for the interconnect was doped lanthanum chromite (LaCrO3), which is a ceramic material which can easily withstand the traditional 1000 C operating temperature. However, the high cost of raw materials and fabrication, difficulties in obtaining high-density chromite parts at reasonable sintering temperatures, and the tendency of the chromite interconnect to partially reduce at the fuel gas/interconnect interface, causing the component to warp and the peripheral seal to break, have plagued the commercialization of planar SOFCs for years. The recent trend in developing lower temperature, more cost-effective cells which utilize anode-supported, several micron-thin electrolytes and/or new electrolytes with improved conductivity make it feasible for lanthanum chromite to be supplanted by metals or alloys as the interconnect materials. Compared to doped lanthanum chromite, metals or alloys offer significantly lower raw material and fabrication costs.
Yang, Z Gary; Stevenson, Jeffry W.; Singh, Prabhakar
Catalysis of Reduction and Oxidation Reactions for Application in Gas Particle Filters
The present study is a first part of an investigation addressing the simultaneous occurrence of oxidation and reduction reactions in catalytic filters. It has the objectives (a) to assess the state of knowledge regarding suitable (types of) catalysts for reduction and oxidation, (b) to collect and analyze published information about reaction rates of both NOx reduction and VOC oxidation, and (c) to adjust a lab-scale screening method to the requirements of an activity test with various oxidation/reduction catalysts.
Udron, L.; Turek, T.
Graphene Oxide Supercapacitors: Computer Simulation Study
About this Abstract. Meeting, 2013 TMS Annual Meeting & Exhibition. Symposium , Nanostructured Materials for Lithium Ion Batteries and for Supercapacitors.
Supercritical water oxidation of landfill leachate
Highlights: > Thermal analysis of NH{sub 3} in supercritical water oxidation reaction. > Research on the catalytic reaction of landfill leachate by using response surface method. > Kinetic research of supercritical water oxidation of NH{sub 3} with and without MnO{sub 2} catalyst. - Abstract: In this paper, ammonia as an important ingredient in landfill leachate was mainly studied. Based on Peng-Robinson formulations and Gibbs free energy minimization method, the estimation of equilibrium composition and thermodynamic analysis for supercritical water oxidation of ammonia (SCWO) was made. As equilibrium is reached, ammonia could be totally oxidized in SCW. N{sub 2} is the main product, and the formation of NO{sub 2} and NO could be neglected. The investigation on SCWO of landfill leachate was conducted in a batch reactor at temperature of 380-500 deg. C, reaction time of 50-300 s and pressure of 25 MPa. The effect of reaction parameters such as oxidant equivalent ratio, reaction time and temperature were investigated. The results showed that COD and NH{sub 3} conversion improved as temperature, reaction time and oxygen excess increased. Compared to organics, NH{sub 3} is a refractory compound in supercritical water. The conversion of COD and NH{sub 3} were higher in the presence of MnO{sub 2} than that without catalyst. The interaction between reaction temperature and time was analyzed by using response surface method (RSM) and the results showed that its influence on the NH{sub 3} conversion was relatively insignificant in the case without catalyst. A global power-law rate expression was regressed from experimental data to estimate the reaction rate of NH{sub 3}. The activation energy with and without catalyst for NH{sub 3} oxidation were 107.07 {+-} 8.57 kJ/mol and 83.22 {+-} 15.62 kJ/mol, respectively.
Wang Shuzhong, E-mail: firstname.lastname@example.com [School of Energy and Power Engineering of Xi' an Jiao Tong University, Xi'an 710049 (China); Guo Yang [School of Energy and Power Engineering of Xi' an Jiao Tong University, Xi'an 710049 (China); Chen Chongming [Hebei Electric Power Research Institute, Shijizhuang, Hebei 050021 (China); Zhang Jie; Gong Yanmeng; Wang Yuzhen [School of Energy and Power Engineering of Xi' an Jiao Tong University, Xi'an 710049 (China)
Atomic Scale Characterization of Complex Oxide Interfaces
Complex oxides exhibit the most disparate behaviors, from ferroelectricity to high Tc superconductivity, colossal magnetoresistance to insulating properties. For these reasons, oxide thin films are of interest for electronics and the emerging field of spintronics. But epitaxial complex oxide ultrathin films and heterostructures can be significantly affected or even dominated by the presence of interfaces and may exhibit intriguing new physical properties quite different from the bulk. A study of the relations between structure and chemistry at the atomic scale is needed to understand the macroscopic properties of such "interface-controlled" materials. For this purpose, the combination of aberration corrected Z-contrast scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) represents a very powerful tool. The availability of sub- ngstr m probes allows a level of unprecedented detail when analyzing not only the interface structure with sensitivity to single atoms, but also the interface chemistry. In this work state of the art STEM-EELS will be applied to the study of different oxide interfaces in heterostructures with titanates, manganites and cuprates based on the perovskite structure.
Varela del Arco, Maria [ORNL; Pennycook, Timothy J [ORNL; Tian, Wei [ORNL; Mandrus, David [ORNL; Pennycook, Stephen J [ORNL; Pena, V. [Universidad Complutense, Spain; Sefrioui, Z. [Universidad Complutense, Spain; Santamaria, J. [Universidad Complutense, Spain
Kinetics of the reactions of hydrogen fluoride with calcium oxide
This paper studies the kinetics of interaction of gaseous hydrogen fluoride with calcium oxide at temperatures 300-700 degrees. The experiments were conducted in a laboratory adsorption apparatus modified and adapted for work with corrosive hydrogen fluoride. Calcium oxide samples in granulated form and deposited on gamma-alumina were used in the experiments. Kinetic curves representing variations of the degree of conversion of the solid samples with time are shown. The influence of retardation dure to diffusion was observed in the experiments. The influence of diffusion control on the reaction rate was also observed in a study of the reaction kinetics on supported layers of calcium oxide.
Kossaya, A.M.; Belyakov, B.P.; Kuchma, Z.V.; Sandrozd, M.K.; Vasil'eva, V.G.
Evolution of Nitrogen Oxide Chemistry in the Nocturnal Boundary Layer
The nocturnal cycle of nitrogen oxides in the atmospheric boundary layer is studied by means of a one-dimensional model. The model solves the conservation equations of momentum, entropy, total water content, and of five chemical species. The ...
S. Galmarini; P. G. Duynkerke; J. VilÓ-Guerau de Arellano
MEAM with Charge Transfer for TM Oxide Modeling
Abstract Scope, Transition metal (TM) oxides are important material with diverse applications including ... Density functional theory (DFT) modeling studies have provided useful bulk ... Atomistic Modeling of Radiation Damage in bcc Uranium.
The Effect of Nanostructure on the High-temperature Oxidation ...
In the present study conventional and nanostructured bulk ?-NiAl samples were ... of ReaxFF Reactive Force Fields to Oxidation Reactions in Ni/Al Metal Alloys.
Properties and Characterization of Nano-Structured Metal Oxides ...
The objective of this study was to synthesize numerous metal oxide nano- structures including TiO2, Nb-doped TiO2, SnO2, ZnO, and NiO and deposit theseĀ...
Iron-oxide catalyzed silicon photoanode for water splitting
This thesis presents an integrated study of high efficiency photoanodes for water splitting using silicon and iron-oxide. The fundamental limitations of silicon to water splitting applications were overcome by an ultrathin ...
Jun, Kimin
Selective Oxidation of Organic Substrates to Partially Oxidized Products
controlled rate of catalysis, utilizing ozone for oxidation of alcohols to ketones or aldehydes, is made possible with this environmentally friendly and versatile technology.
Oxidation resistant alloys, method for producing oxidation resistant alloys
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
Dunning, John S.; Alman, David E.
Lignite slime as activator in production of oxidized asphalts
The possibility of activation of the oxidation of straight-run resids to asphalts by the addition of lignite slimes obtained in the liquefaction of coals of the Kansk-Achinsk basin was studied on the basis of a hypothesis formulated with due regard for the principles of physicochemical mechanics of petroleum disperse systems. A reduction of the air bubble size in the oxidizing vessel should lead to an increase in the total surface of oxidation and hence to a shortening of the time required for oxidation of the feed. A straight-run vacuum resid from mixed West Siberian and Ukhta crudes was used. The resid was oxidized with and without the addition of slime.
Gureev, A.A.; Gorlov, E.G.; Leont'eva, O.B.; Zotova, O.V.
Catalyst Additives to Enhance Mercury Oxidation and Capture
Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. Three different SCR catalysts are currently being studied in this project--honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Future work to characterize flue gas simulations typically derived from low and high sulfur bituminous coal are being performed in a stepwise manner, to avoid the constant interruptions in testing that occur when leaks in the system are generated during temperature transitions. Specifically, chlorine concentration vs. mercury oxidation correlations will be developed for each catalyst. The contributions of temperature are also being investigated. SO2 oxidation is also being investigated for each test condition.
Thomas K. Gale
Ultra supercritical steamside oxidation
Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, which are part of the U.S. Department of Energy's Vision 21 goals. Most current coal power plants in the U.S. operate at a maximum steam temperature of 538 C. However, new supercritical plants worldwide are being brought into service with steam temperatures of up to 620 C. Vision 21 goals include steam temperatures of up to 760 C. This research examines the steamside oxidation of advanced alloys for use in USC systems. Emphasis is placed on alloys for high- and intermediate-pressure turbine sections. Initial results of this research are presented.
Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, M.; Alman, David A.; Ochs, Thomas L.
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.
West, J.M.; Schumar, J.F.
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)
Haws, C.C. Jr.
A theoretical study of the ground state and lowest excited states of PuO0/+/+2 and PuO20/+/+2
values. KEYWORDS Plutonium oxides; multiconfigurationalcertainly widely studied. Plutonium systems have also beenthermodynamics of elementary plutonium oxide molecules PuO
Gibson, John K.
OH-initiated heterogeneous aging of highly oxidized organic aerosol
The oxidative evolution (ōagingö) of organic species in the atmosphere is thought to have a major influence on the composition and properties of organic particulate matter, but remains poorly understood, particularly for the most oxidized fraction of the aerosol. Here we measure the kinetics and products of the heterogeneous oxidation of highly oxidized organic aerosol, with an aim of better constraining such atmospheric aging processes. Submicron particles composed of model oxidized organicsŚ1,2,3,4-butanetetracarboxylic acid (C{sub 8}H{sub 10}O{sub 8}), citric acid (C{sub 6}H{sub 8}O{sub 7}), tartaric acid (C{sub 4}H{sub 6}O{sub 6}), and Suwannee River fulvic acidŚwere oxidized by gas-phase OH in a flow reactor, and the masses and elemental composition of the particles were monitored as a function of OH exposure. In contrast to our previous studies of less-oxidized model systems (squalane, erythritol, and levoglucosan), particle mass did not decrease significantly with heterogeneous oxidation. Carbon content of the aerosol always decreased somewhat, but this mass loss was approximately balanced by an increase in oxygen content. The estimated reactive uptake coefficients of the reactions range from 0.37 to 0.51 and indicate that such transformations occur at rates corresponding to 1-2 weeks in the atmosphere, suggesting their importance in the atmospheric lifecycle of organic particulate matter.
Kessler, Sean H.; Nah, Theodora; Daumit, Kelly E.; Smith, Jared D.; Leone, Stephen R.; Kolb, Charles E.; Worsnop, Douglas R.; Wilson, Kevin R.; Kroll, Jesse H.
Improved Initial Performance of Si Nanoparticles by Surface Oxide Reduction
Improved Initial Performance of Si Nanoparticles by Surface Oxide Reduction Improved Initial Performance of Si Nanoparticles by Surface Oxide Reduction for Lithium-Ion Battery Application Title Improved Initial Performance of Si Nanoparticles by Surface Oxide Reduction for Lithium-Ion Battery Application Publication Type Journal Article Year of Publication 2011 Authors Xun, Shidi, Xiangyun Song, Michael E. Grass, Daniel K. Roseguo, Z. Liu, Vincent S. Battaglia, and Gao Li Journal Electrochemical Solid-State Letters Volume 14 Start Page A61 Issue 5 Pagination A61-A63 Date Published 02/2001 Keywords Electrochemistry, elemental semiconductors, etching, lithium, nanoparticles, secondary cells, silicon, thermal analysis, transmission electron microscopy, X-ray photoelectron spectra Abstract This study characterizes the native oxide layer of Si nanoparticles and evaluates its effect on their performance for Li-ion batteries. x-ray photoelectron spectroscopy and transmission electron microscopy were applied to identify the chemical state and morphology of the native oxide layer. Elemental and thermogravimetric analysis were used to estimate the oxide content for the Si samples. Hydrofluoric acid was used to reduce the oxide layer. A correlation between etching time and oxide content was established. The initial electrochemical performances indicate that the reversible capacity of etched Si nanoparticles was enhanced significantly compared with that of the as-received Si sample.
Effects of Water Vapor on Oxidation Behavior of Ferritic Stainless Steels Under Solid Oxide Fuel Cell Interconnect Exposure Conditions
The oxidation of ferritic stainless steels has been studied under solid oxide fuel cell (SOFC) interconnect ''dual'' exposure conditions, i.e. simultaneous exposure to air on one side of the sample, and fuel (hydrogen) on the other. It was found that, under the dual exposures, the oxidation behavior of the stainless steels at the airside differed significantly from that observed during exposure to air at both sides. Increased water vapor partial pressure in the air at the airside further accelerated the anomalous oxidation, resulting in nucleation and growth of hematite in the scale that led to a localized attack. The accelerated oxidation and growth of the hematite nodules was a result of combined effects of hydrogen transport from the fuel side to the airside and the presence of increased water vapor.
Yang, Z Gary; Xia, Gordon; Singh, Prabhakar; Stevenson, Jeffry W.
(IV) Oxide and Barium Titanate
In a first investigation of its kind, a commercially available additive manufacturing platform has been applied to ōprintö metal oxide gas sensors. The M-Lab fromĀ...
Oxides, Steels, and Nuclear Materials
Mar 14, 2012 ... This discussion will be illustrated with examples from solid oxide fuel cells, lithium ion batteries and high-temperature superconductors.
Enhanced Thermal Conductivity Oxide Fuels
the purpose of this project was to investigate the feasibility of increasing the thermal conductivity of oxide fuels by adding small fractions of a high conductivity solid phase.
Alvin Solomon; Shripad Revankar; J. Kevin McCoy
Continuous lengths of oxide superconductors
A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.
Kroeger, Donald M. (Knoxville, TN); List, III, Frederick A. (Andersonville, TN)
Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Final report
Coal oxidation has been studies extensively in previous work. However, there is still no general agreement concerning the mechanisms of oxidation. Moreover, the oxidation behavior of coal and mineral matter have generally been regarded as separate processed. There is appreciable evidence that organic and inorganic oxidation process are actually coupled, consequently the changes in their surface properties induced by oxidation are difficult to predict. This makes the effectively of coal cleaning processes highly sensitive to the extent of weathering and oxidation that the coal has experienced. The objective of this research was to investigate the oxidation behavior of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with these surface properties that would influence the behavior in physical cleaning processes.
Doyle, F.M.
Preignition oxidation characteristics of hydrocarbon fuels
Experimental results obtained from a static reactor are presented for the oxidation of a variety of fuels. Pressure and temperature histories of the reacting fuel/oxidizer mixtures were obtained. Measurements of the stable reaction intermediate and product species were made using gas chromatographic analysis. One aspect of this work involved detailed studies of the oxidation chemistry of relatively low molecular weight aliphatic hydrocarbons: propane, propene, and n-butane. The oxidation chemistry of these fuels was examined at temperatures in the range 550-750 K, equivalence ratios ranging from 0.8 to 4.0 and at subatmospheric pressures. The main characteristics and features of the oxidation mechanisms were determined for each fuel in each temperature regime. The experimental results from propene and propane were used to develop a low and intermediate temperature kinetic mechanism for these fuels based on a low temperature acetaldehyde mechanism of Kaiser et al. and a high temperature propene/propane mechanism of Westbrook and Pitz. General preignition characteristics of higher molecular weight hydrocarbons and binary mixtures of these fuels were also studied. The low temperature/cool flame ignition characteristics of dodecane were investigated at temperatures in the range 523-623 K, equivalence s ranging from 0.8 to 1.0 and at subatmospheric pressures. The preignition characteristics of binary mixtures of dodecane and the aromatic component tetralin were examined. The addition of the tetralin had the overall effect of decreasing the ignition tendency of the mixture, although this effect was nonlinear with respect to the amount of tetralin added.
Wilk, R.D.
Spectroscopic ellipsometry of electrochemical precipitation and oxidation
Spectroscopic ellipsometry of electrochemical precipitation and oxidation Spectroscopic ellipsometry of electrochemical precipitation and oxidation of nickel hydroxide films Title Spectroscopic ellipsometry of electrochemical precipitation and oxidation of nickel hydroxide films Publication Type Journal Article Year of Publication 1998 Authors Kong, Fanping, Robert Kostecki, Frank R. McLarnon, and Rolf H. Muller Journal Thin Solid Films Volume 313-314 Pagination 775-780 Keywords effective medium approximation, electrochemical precipitation, inhomogeneous films, nickel hydroxide, spectroscopic ellipsometry Abstract In situ spectroscopic ellipsometry was used to investigate the electrochemical precipitation of nickel hydroxide films. By use of optical models for inhomogeneous films it was found that a specific precipitation current density produced the most compact and homogeneous film structures. The density of nickel hydroxide films was derived to be 1.25-1.50 g/cm3. The redox behavior of precipitated nickel hydroxide films was studied with an effective-medium optical model. Incomplete conversion to nickel oxyhydroxide and a reduction in film thickness were found during the oxidation cycle.
Methane oxidation over dual redox catalysts
The objective of this research is to develop approaches to direct catalytic oxidation of methane over oxides that are doubly doped with transition metal ions. The desired process aims at employing a double redox mechanism, where one redox couple is utilized for activation of oxygen and another for the trapping of CH{sub 3} radicals. The methyl radicals can either recombine, giving C{sub 2} hydrocarbons, or be converted, via electron transfer reaction, to carbocations. The latter species can react with surface OH{sup {minus}} groups to form methanol or formaldehyde. To choose from several possible catalytic systems, this research initially involved the characterization of the micromorphology and crystalline dimensions of zinc oxide catalysts doped with Cu, Fe, and Sn by scanning electron microscopy. In addition, the determination of surface composition and oxidation states by X-ray photoelectron spectroscopy was carried out. A newly constructed high temperature catalytic testing system has been calibrated (flow meters and temperature controllers), tested for possible gas leaks and integrated with a gas chromatographic analytical unit. A preliminary catalytic test study over a Cu/Fe/ZnO sample was performed. The following products of the methane coupling reaction was found: C{sub 2}H{sub 6}, C{sub 2}H{sub 4} and H{sub 2}O together with CO{sub 2}. The maximum space time yield of 14 mmol C{sub 2} hydrocarbons/g cat/h was obtained at 848{degrees}C.
Klier, K.; Herman, R.G.; Sojka, Z.
Operation of staged membrane oxidation reactor systems
A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.
Repasky, John Michael
Method for hot pressing beryllium oxide articles
The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide - lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.
Ballard, A.H.; Godfrey, T.G. Jr.; Mowery, E.H.
Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, October 1--December 31, 1993
This report covers the time period from October 1 through December 31, 1993. A description of tasks for fiscal year 1994 is included in this report. Highlights and progress of work performed during this quarter is reported in (a) catalytic steam gasification of coals and cokes; (b) oxidative coupling of methane; and (c) synthesis and characterization of catalysts. Attached to this report is a copy of a manuscript submitted to Proceeding of Fuels Technology Contractors Meeting {open_quotes}Steady-State and Transient Catalytic Oxidation and Coupling of Methane{close_quotes} by Heinemann, Iglesia, and Perry.
Heinemann, H.; Iglesia, E.; Perry, D.L.
Ceramic oxide powders and the formation thereof
Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions. 14 figures.
Katz, J.L.; Chenghung Hung.
Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions.
Katz, Joseph L. (Baltimore, MD); Hung, Cheng-Hung (Baltimore, MD)
Low Temperature Constrained Sintering of Cerium Gadolinium Oxide Films for Solid Oxide Fuel Cell Applications
Temperature Solid Oxide Fuel Cells, In: S.C. Singhal and M.Tubular Solid Oxide Fuel Cell Technology, U.S. Department ofOxide Films for Solid Oxide Fuel Cell Applications by Jason
Nicholas, Jason.D.
Chemically homogeneous and thermally reversible oxidation of epitaxial graphene
With its exceptional charge mobility, graphene holds great promise for applications in next-generation electronics. In an effort to tailor its properties and interfacial characteristics, the chemical functionalization of graphene is being actively pursued. The oxidation of graphene via the Hummers method is most widely used in current studies, although the chemical inhomogeneity and irreversibility of the resulting graphene oxide compromises its use in high-performance devices. Here, we present an alternative approach for oxidizing epitaxial graphene using atomic oxygen in ultrahigh vacuum. Atomic-resolution characterization with scanning tunnelling microscopy is quantitatively compared to density functional theory, showing that ultrahigh-vacuum oxidization results in uniform epoxy functionalization. Furthermore, this oxidation is shown to be fully reversible at temperatures as low as 260 8C using scanning tunnelling microscopy and spectroscopic techniques. In this manner, ultrahigh-vacuum oxidation overcomes the limitations of Hummers-method graphene oxide, thus creating new opportunities for the study and application of chemically functionalized graphene.
Hossain, Md. Zakir [Northwestern University, Evanston; Johns, James E. [Northwestern University, Evanston; Bevan, Kirk H [ORNL; Karmel, Hunter J. [Northwestern University, Evanston; Liang, Yu Teng [Northwestern University, Evanston; Yoshimoto, Shinya [University of Tokyo, Tokyo, Japan; Mukai, Kozo [University of Tokyo, Tokyo, Japan; Koitaya, Tatanori [University of Tokyo, Tokyo, Japan; Yoshinobu, Jun [University of Tokyo, Tokyo, Japan; Kawai, Maki [University of Tokyo, Tokyo, Japan; Lear, Amanda M. [Indiana University; Kesmodel, Larry L. [Indiana University; Tait, Steven L. [Indiana University; Hersam, Mark C. [Northwestern University, Evanston
Thermal oxidation of tungsten-based sputtered coatings
The effect of the addition of nickel, titanium, and nitrogen on the air oxidation behavior of W-based sputtered coatings in the temperature range 600 to 800 C was studied. In some cases these additions significantly improved the oxidation resistance of the tungsten coatings. As reported for bulk tungsten, all the coatings studied were oxidized by layers following a parabolic law. Besides WO{sub 3} and WO{sub x} phases detected in all the oxidized coatings, TiO{sub 2} and NiWO{sub 4} were also detected for W-Ti and W-Ni films, respectively. WO{sub x} was present as an inner protective compact layer covered by the porous WO{sub 3} oxide. The best oxidation resistance was found for W-Ti and W-N-Ni coatings which also presented the highest activation energies (E{sub a} = 234 and 218 kJ/mol, respectively, as opposed to E{sub a} {approx} 188 kJ/mol for the other coatings). These lower oxidation weight gains were attributed to the greater difficulty of the inward diffusion of oxygen ions for W-Ti films, owing to the formation of fine particles of TiO{sub 2}, and the formation of the external, more protective layer of NiWO{sub 4} for W-N-Ni coatings.
Louro, C.; Cavaleiro, A. [Dept. de Engenharia Mecanica-Polo II, Coimbra (Portugal)
Changes in physical and chemical structure of the micropore system in eight solvent swelled Argonne Premium Coal Sample (APCS) coals upon weathering were studied using the EPR spin probe method. Spin probes, which are allowed to diffuse into the coal structure during swelling, are trapped when the swelling solvent is removed. Excess spin probes are removed from the coal surface and larger pores so that only the presence of spin probes trapped in pores which closely approximate the size of the spin probe are detected. Detailed explanations and illustrations of the experimental procedure used are given. Careful examination of the weathering process on coal as a function of rank was accomplished using the EPR spin probe method. The retention of spin probes in eight APCS coals provided valuable insight into both the loss of water and the oxidation which occur during the weathering process. The results could be explained in terms of the autoxidation process observed in other polymeric systems. It was shown that initial oxidation of coal can result in increased cross-linking in the coal structure. As the oxidation process continued, both the covalent and hydrogen bonded character of the coal were significantly altered. The retention character of some coals during oxidation was shown to change by as much as three orders of magnitude. Experiments were performed to study the effects of short term oxidation and dehydration on coal structure by exposing the coal samples to argon or oxygen for time periods up to five minutes. The results indicate that the structure of coal is extremely sensitive to environmental changes and exhibits significant changes in as little as 30 seconds. Exposure of Illinois No.6 coal to argon or oxygen for 30 seconds caused a decrease in the retention of polar spin probes by as much as an order of magnitude. The studies presented here suggest that the structure of coal is dynamic in nature, and has an intimate relationship with the nature of its environment. This method has been shown to be very sensitive to structural changes brought about in coal by oxidation and dehydration, and can be used to follow changes in coal during the swelling process. Additional ideas for future studies using the EPR spin probe method are also discussed.
Lowell D. Kispert
Ultra Supercritical Steamside Oxidation
Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, which are goals of the U.S. Department of Energy's Advanced Power Systems Initiatives. Most current coal power plants in the U.S. operate at a maximum steam temperature of 538 C. However, new supercritical plants worldwide are being brought into service with steam temperatures of up to 620 C. Current Advanced Power Systems goals include coal generation at 60% efficiency, which require steam temperatures of up to 760 C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections. Initial results of this research are presented.
Holcomb, Gordon R.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, Malgorzata
Slurry calcination process for conversion of aqueous uranium and plutonium to a mixed oxide powder
Pilot plant studies indicate that a slurry calcination process for conversion of uranium and plutonium solutions to a mixed oxide powder can be operated at a plant scale.
Jones, M K; Jenkins, W J
Reduction of the Ni- and Ti-oxide mixtures by natural gas
In this work, the reduction of Ni- and Ti-oxides by natural gas has been studied. ... Reaction mechanism and reaction rate of Sn evaporation from liquid steel.
Lipid Oxidation and Quality Division of AOCS
For professionals in lipid oxidation with a major focus in food applications including flavor, instrumentation, chemical analyses, biological oxidation, antioxidants, nutraceuticals, processing and mechanisms Lipid Oxidation and Quality Division of AOCS ...
Emergent Phenomena at Complex Oxide Interfaces
Complex Oxide Interfaces by Pu Yu A dissertation submittedOxide Interfaces Copyright 2011 by Pu Yu Abstract Emergentat Complex Oxide Interfaces by Pu Yu Doctor of Philosophy in
Yu, Pu
Ethanol oxidation on metal oxide-supported platinum catalysts
Ethanol is a renewable fuel that can be used as an additive to gasoline (or its substitute) with the advantage of octane enhancement and reduced carbon monoxide exhaust emissions. However, on Ethanol is a renewable fuel that can be used as an additive to gasoline (or its substitute) with the advantage of octane enhancement and reduced carbon monoxide exhaust emissions. However, on the standard three-way catalysts, the conversion of unburned ethanol is low because both ethanol and some of its partially oxidized derivatives are highly resistant to oxidation. A combination of first-principles density-functional theory (DFT) based calculations and in-situ diffuse reflectance infrared spectroscopy (DRIFTS) analysis was applied to uncover some of the fundamental phenomena associated with ethanol oxidation on Pt containing catalysts. In particular, the objective was to analyze the role of the oxide (i.e., ?-Al2O3 or SiO2) substrate on the ethanol oxidation activity. The results showed that Pt nanoparticles trap and accumulate oxygen at their surface and perimeter sites and play the role of ōstovesö that burn ethanol molecules and their partially oxidized derivatives to the ōfinalö products. The ?-Al2O3 surfaces provided higher mobility of the fragments of ethanol molecules than the SiO2 surface and hence increased the supply rate of these objects to the Pt particles. This will in turn produce a higher conversion rate of unburned ethanol.and some of its partially oxidized derivatives are highly resistant to oxidation. A combination of first-principles density-functional theory (DFT) based calculations and in-situ diffuse reflectance infrared spectroscopy (DRIFTS) analysis was applied to uncover some of the fundamental phenomena associated with ethanol oxidation on Pt containing catalysts. In particular, the objective was to analyze the role of the oxide (i.e., ?-Al2O3 or SiO2) substrate on the ethanol oxidation activity. The results showed that Pt nanoparticles trap and accumulate oxygen at their surface and perimeter sites and play the role of ōstovesö that burn ethanol molecules and their partially oxidized derivatives to the ōfinalö products. The ?-Al2O3 surfaces provided higher mobility of the fragments of ethanol molecules than the SiO2 surface and hence increased the supply rate of these objects to the Pt particles. This will in turn produce a higher conversion rate of unburned ethanol.
L. M. Petkovic 090468; Sergey N. Rashkeev; D. M. Ginosar
Structural Evolution of Carbon During Oxidation
The examination of the structural evolution of carbon during oxidation has proven to be of scientific interest. Early modeling work of fluidized bed combustion showed that most of the reactions of interest occurs iOn the micropores, and this work has concentrated on these pores. This work has concentrated on evolution of macroporosity and rnicroporosity of carbons during kinetic controlled oxidation using SAXS, C02 and TEM analysis. Simple studies of fluidized bed combustion of coal chars has shown that many of the events considered fragmentation events previously may in fact be "hidden" or nonaccessible porosity. This makes the study of the microporous combustion characteristics of carbon even more important. The generation of a combustion resistant grid, coupled with measurements of the SAXS and C02 surface areas, fractal analysis and TEM studies has confined that soot particles shrink during their oxidation, as previously suspected. However, this shrinkage results in an overall change in structure. This structure becomes, on a radial basis, much more ordered near the edges, while the center itself becomes transparent to the TEM beam, implying a total lack of structure in this region. Although complex, this carbon structure is probably burning as to keep the density of the soot particles nearly the same. The TEM techniques developed for examination of soots has also been applied to Spherocarb. The Spherocarb during oxidation also increases its ordering,. This ordering, by present theories, would imply that the reactivity would go. However, the reactivity goes up, implying that structure of carbon is secondary in importance to catalytic effects.
Adel F. Sarofim; Angelo Kandas
Atlas of Steam-Side Oxide Scales ¢ 2013 Update
The Electric Power Research Institute (EPRI) has conducted research for a number of years to advance the understanding of high-temperature steam-side oxidation and exfoliation in boiler tubes. The research has spanned a variety of activities, including fundamental and applied modeling of the oxidation and exfoliation process, examination of tubes taken from service, and laboratory studies to understand the effects of alloy composition, surface engineering, and processing. In 2012, an EPRI-NPL ...
Development of Nitric Oxide Oxidation Catalysts for the Fast SCR Reaction
This study was undertaken in order to assess the potential for oxidizing NO to NO{sub 2} in flue gas environments, with the aim of promoting the so-called fast SCR reaction. In principle this can result in improved SCR kinetics and reduced SCR catalyst volumes. Prior to commencing experimental work, a literature study was undertaken to identify candidate catalysts for screening. Selection criteria comprised (1) proven (or likely) activity for NO oxidation, (2) low activity for SO2 oxidation (where data were available), and (3) inexpensive component materials. Catalysts identified included supported base metal oxides, supported and unsupported mixed metal oxides, and metal ion exchanged ZSM-5 (Fe, Co, Cu). For comparison purposes, several low loaded Pt catalysts (0.5 wt% Pt) were also included in the study. Screening experiments were conducted using a synthetic feed gas representative of flue gas from coal-fired utility boilers: [NO] = 250 ppm, [SO{sub 2}] = 0 or 2800 ppm, [H{sub 2}O] = 7%, [CO{sub 2}] = 12%, [O{sub 2}] = 3.5%, balance = N{sub 2}; T = 275-375 C. Studies conducted in the absence of SO{sub 2} revealed a number of supported and unsupported metal oxides to be extremely active for NO oxidation to NO{sub 2}. These included known catalysts (Co{sub 3}O{sub 4}/SiO{sub 2}, FeMnO{sub 3}, Cr{sub 2}O{sub 3}/TiO{sub 2}), as well as a new one identified in this work, CrFeO{sub x}/SiO{sub 2}. However, in the presence of SO{sub 2}, all the catalysts tested were found to be severely deactivated with respect to NO oxidation. Of these, Co{sub 3}O{sub 4}/SiO{sub 2}, Pt/ZSM-5 and Pt/CeO{sub 2} showed the highest activity for NO oxidation in the presence of SO{sub 2} (based on peak NO conversions to NO{sub 2}), although in no cases did the NO conversion exceed 7%. Reactor studies indicate there are two components to SO{sub 2}-induced deactivation of Co{sub 3}O{sub 4}/SiO{sub 2}, corresponding to an irreversible deactivation due to sulfation of the surface of the Co{sub 3}O{sub 4} phase, together with a reversible inhibition due to competitive adsorption of SO{sub 2} with NO on the catalyst. In an effort to minimize the deactivating effect of SO{sub 2} on Co{sub 3}O{sub 4}/SiO{sub 2}, two synthetic approaches were briefly examined. These consisted of (1) the incorporation of highly dispersed Co(II) ions in silica, as a non-sulfating matrix, via the sol-gel preparation of CoO-SiO{sub 2}; and (2) the sol-gel preparation of a mixed metal oxide, CoO-Nb{sub 2}O{sub 5}-SiO{sub 2}, with the aim of exploiting the acidity of the niobium oxide to minimize SO2 adsorption. While both catalysts showed almost no activity for NO oxidation in the absence of SO{sub 2}, when SO{sub 2} was present low activity was observed, indicating that SO{sub 2} acts as a promoter for NO oxidation over these materials. The kinetics of NO oxidation over Co{sub 3}O{sub 4}/SiO{sub 2}, Pt/SiO{sub 2} and Pt/CeO{sub 2} were also examined. Co{sub 3}O{sub 4}/SiO{sub 2} was found to exhibit a higher apparent activation energy for NO oxidation than the Pt catalysts, while the combined reaction order in NO and O{sub 2} for the three catalysts was very close to one. CO{sub 2} was found to have no effect on the kinetics of NO oxidation over these catalysts. The presence of H{sub 2}O caused a decrease in NO conversion for both Co{sub 3}O{sub 4}/SiO{sub 2} and Pt/CeO{sub 2} catalysts, while no effect was observed for Pt/SiO{sub 2}. The inhibiting effect of water was reversible and is attributed to competitive adsorption with the reactants. In sum, this study has shown that a variety of base metal catalysts are very active for NO oxidation. However, all of the catalysts studied are strongly deactivated in the presence of 2800 ppm SO{sub 2} at typical flue gas temperatures; consequently improving catalyst resistance to SO{sub x} will be a pre-requisite if the fast SCR concept is to be applied to coal-fired flue gas conditions.
Mark Crocker
Interfaces in Nanostructured Functional Oxide Thin Films
The thin film systems include high temperature superconductors (HTS), thin film solid oxide fuel cells (SOFC), and other functional oxide systems. DetailedĀ...
Experimental Characterization of Manganese Cobalt Oxide (MCO)
A Novel Electrode Material for Symmetrical Solid Oxide Fuel Cells ... High Performance Oxide Protective Coatings for SOFC Components Ę Influence of PoreĀ...
Hydrogen & Fuel Cells - Fuel Cell - Solid Oxide
Electrolyzer Research and Development Solid Oxide Fuel Cells Solid oxide diagram In an SOFC, oxygen from air is reduced to ions at the cathode, which diffuse through the...
New manganese catalyst for light alkane oxidation
Aluminophosphates containing manganese in the structural framework are employed for the oxidation of alkanes, for example the vapor phase oxidation of methane to methanol.
Durante, Vincent A. (West Chester, PA); Lyons, James E. (Wallingford, PA); Walker, Darrell W. (Visalia, CA); Marcus, Bonita K. (Radnor, PA)
Final technical report. Bimetallic complexes as methanol oxidation catalysts
Our work on the electrocatalyzed oxidation of methanol was initially motivated by the interest in methanol as an anodic reactant in fuel cells. The literature on electrochemical oxidation of alcohols can be roughly grouped into two sets: fuel cell studies and inorganic chemistry studies. Work on fuel cells primarily focuses on surface-catalyzed oxidation at bulk metal anodes, usually Pt or Pt/Ru alloys. In the surface science/electrochemistry approach to these studies, single molecule catalysts are generally not considered. In contrast, the inorganic community investigates the electrooxidation of alcohols in homogeneous systems. Ruthenium complexes have been the most common catalysts in these studies. The alcohol substrates are typically either secondary alcohols (e.g., isopropanol) such that the reaction stops after 2 e{sup -} oxidation to the aldehyde and 4 e{sup -} oxidation to the carboxylic acid can be observed. Methanol, which can also undergo 6 e{sup -} oxidation to CO{sub 2}, rarely appears in the homogeneous catalysis studies. Surface studies have shown that two types of metal centers with different functions result in more effective catalysts than a single metal; however, application of this concept to homogeneous systems has not been demonstrated. The major thrust of the work is to apply this insight from the surface studies to homogeneous catalysis. Even though homogeneous systems would not be appropriate models for active sites on Pt/Ru anodes, it is possible that heterobimetallic catalysts could also utilize two metal centers for different roles. Starting from that perspective, this work involves the preparation and investigation of heterobinuclear catalysts for the electrochemical oxidation of methanol.
McElwee-White, Lisa
Review of the oxidation rate of zirconium alloys.
The oxidation of zirconium alloys is one of the most studied processes in the nuclear industry. The purpose of this report is to provide in a concise form a review of the oxidation process of zirconium alloys in the moderate temperature regime. In the initial ''pre-transition'' phase, the surface oxide is dense and protective. After the oxide layer has grown to a thickness of 2 to 3 {micro}m's, the oxidation process enters the ''post-transition'' phase where the density of the layer decreases and becomes less protective. A compilation of relevant data suggests a single expression can be used to describe the post-transition oxidation rate of most zirconium alloys during exposure to oxygen, air, or water vapor. That expression is: Oxidation Rate = 13.9 g/(cm{sup 2}-s-atm{sup -1/6}) exp(-1.47 eV/kT) x P{sup 1/6} (atm{sup 1/6}).
Causey, Rion A. (Sandia National Laboratories, Livermore, CA); Cowgill, Donald F. (Sandia National Laboratories, Livermore, CA); Nilson, Robert H. (Sandia National Laboratories, Livermore, CA)
NIST{endash}JANAF Thermochemical Tables for the Iodine Oxides
The thermodynamic and spectroscopic properties of the iodine oxide species have been reviewed. Recommended NIST{endash}JANAF Thermochemical Tables are given for six gaseous iodine oxides: IO, OIO, IOO, IOI, IIO, and IO{sub 3}. Sufficient information is not available to generate thermochemical tables for any condensed phase species. Annotated bibliographies (over 400 references) are provided for all neutral iodine oxides which have been reported in the literature. There is a lack of experimental thermodynamic and spectroscopic information for all iodine oxide species, except IO(g) and OIO(g). The recommended thermochemical tables are based on estimates for the structure, vibrational frequencies, and enthalpy of formation based in part on the spectroscopic and thermodynamic data for the other halogen oxides [J. Phys. Chem. Ref. Data {bold 25}, 551 (1996); {bold 25}, 1061 (1996)]. Although there is a definite lack of information in comparison with the other halides, this information is provided for the iodine oxides for the following reasons: (1) to complete the study of the halogen oxide family and (2) to stress the need for additional experimental measurements. Of all the species mentioned in the literature, many have not been isolated or characterized. In fact, some do not exist. Throughout this paper, uncertainties attached to recommended values correspond to the uncertainty interval, equal to twice the standard deviation of the mean. {copyright} {ital 1996 American Institute of Physics and American Chemical Society.}
Chase, M.W. [Standard Reference Data Program, National Institute of Standards and Technology, Gaithersburg, Maryland 20879 (United States)
Controlled VLS Growth of Indium, Gallium and Tin Oxide Nanowires via Chemical Vapor Transport
technique to synthesize indium oxide, gallium oxide, and tinmaterial systems such as indium oxide, gallium oxide and tinand Characterization A. Indium Oxide Nanowires Indium oxide
Johnson, M.C.; Aloni, S.; McCready, D.E.; Bourret-Courchesne, E.D.
The objective of this project is to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involves both experimental and modeling efforts. The team is comprised of the University of Utah, Reaction Engineering International, and the University of Connecticut. The objective is to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters to be studied include HCl, NO{sub x}, and SO{sub 2} concentrations, ash constituents, and temperature. This report summarizes Year 3 results for the experimental and modeling tasks. Experiments have been completed on the effects of chlorine. However, the experiments with sulfur dioxide and NO, in the presence of water, suggest that the wet-chemistry analysis system, namely the impingers, is possibly giving erroneous results. Future work will investigate this further and determine the role of reactions in the impingers on the oxidation results. The solid-phase experiments have not been completed and it is anticipated that only preliminary work will be accomplished during this study.
JoAnn S. Lighty; Geoffrey Silcox; Andrew Fry; Joseph Helble; Balaji Krishnakumar
FGDExpert Demonstration at NIPSCO Schahfer Unit 17: Oxidation Reduction Potential Effects on Scrubber Chemistry
Flue gas desulfurization (FGD) systems have been shown to remove soluble oxidized mercury (Hg), as well as selenium (Se), from flue gas. However, one phenomenon that has been observed, but not well characterized, is the re-emission of oxidized Hg captured in the FGD scrubber as elemental Hg. Several studies have shown that oxidation reduction potential (ORP) influences the re-emission of Hg from FGD scrubbers. Other studies have demonstrated that ORP influences the speciation of Se in the scrubber ...
The objective of this project is to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involves two experimental scales and a modeling effort. The team is comprised of University of Utah, Reaction Engineering International, and University of Connecticut. The objective is to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters to be studies include HCl, NOx, and SO{sub 2} concentrations, ash constituents, and temperature. This report summarizes Year 1 results for the experimental and modeling tasks. Experiments in the drop tube are just beginning and a new, speciated mercury analyzer is up and running. A preliminary assessment has been made for the drop tube experiments using the existing model of gas-phase kinetics.
JoAnn S. Lighty; Geoffrey Silcox; Andrew Fry; Constance Senior; Joseph Helble
Analysis of Some Uranium Oxide and Mixed Oxide Lattice Measurements
A series of critical lattice experiments using uranium oxide and mixed-oxide fuel (uranium-plutonium) moderated by clean or borated water was expected to provide information for testing computer programs and nuclear data libraries used in analyzing nuclear reactor cores. Uncertainties inherent in the measurements must be small for experimental information to be of value in such a validation. In general, experimental parameters such as reaction ratios or disadvantage factors (which can be compared with ca...
In this study, the foundation is being developed for the numerical simulation of the processes that determine the oxide scale exfoliation behavior of the steam-side surfaces of superheater and reheater tubes in a steam boiler. Initially, the assumptions concerning the base state for calculating oxide strains also were critically examined. The state of stress-strain of an oxide growing on the inside surface of an externally-heated tube was considered for the conditions experienced in a boiler during transition from full- to partial-load operation. Since the rate at which the oxide grows is an important consideration, it was necessary to determine the appropriate temperature to use in the oxidation rate calculations. The existence of a temperature gradient through the tube, and the cyclic nature of the boiler operation (temperature and pressure) were considered; the growth temperature of the oxide was taken to be the oxide surface temperature. It was determined that the commonly-used approach for accounting for geometrical effects when calculating stress-strain development in a growing oxide scale of using the analogy of an infinitely-long flat plate gave sufficiently different results than when using a cylindrical geometry, that the latter was adopted as the preferred calculation procedure. Preliminary calculation of strains developed in multilayered oxides formed on alloy T22 as a function of boiler operating conditions indicated the magnitude of the strains in each layer; the large strain gradients between the layers inferred the importance of the detailed scale morphology in determining the mode of exfoliation
Wright, Ian G [ORNL; Sabau, Adrian S [ORNL; Dooley, Barry [Electric Power Research Institute (EPRI)
Advanced Photon Source Activity Report 2002 at Argonne National Laboratory, Argonne, IL, December 2003 - contribution title:"Microdiffraction Study of Epitaxial Growth and Lattice Tilts in Oxide Films on Polycrystalline Metal Substrates"
Texture, the preference for a particular crystallographic orientation in polycrystalline materials, plays an important role in controlling such diverse materials properties as corrosion resistance, recording density in magnetic media and electrical transport in superconductors [1]. Without texture, polycrystalline oxide superconductors contain many high-angle, weak-linked grain boundaries which reduce critical current densities by several orders of magnitude [2]. One approach for inducing texture in oxide superconductors has been the epitaxial growth of films on rolling-assisted biaxially-textured substrates (RABiTS) [3]. In this approach, rolled Ni foils are recrystallized under conditions that lead to a high degree of biaxial {l_brace}001{r_brace}<100> cube texture. Subsequent deposition of epitaxial oxide buffer layers (typically CeO{sub 2} and YSZ as chemical barriers) and superconducting YBCO preserves the lattice alignment, eliminating high-angle boundaries and enabling high critical current densities, J{sub c} > 10{sup 6}/cm{sup 2}. Conventional x-ray diffraction using {omega}- and {phi}-scans typically shows macroscopic biaxial texture to within {approx}5{sup o}-10{sup o} FWHM for all layers, but does not describe the local microstructural features that control the materials properties. Understanding and controlling the local texture and microstructural evolution of processes associated with heteroepitaxial growth, differential thermal contraction and cracking remain significant challenges in this complex system [4], as well as in many other technologically important thin-film applications.
Budai, J.D.
Texture, the preference for a particular crystallographic orientation in polycrystalline materials, plays an important role in controlling such diverse materials properties as corrosion resistance, recording density in magnetic media and electrical transport in superconductors [1]. Without texture, polycrystalline oxide superconductors contain many high-angle, weak-linked grain boundaries which reduce critical current densities by several orders of magnitude [2]. One approach for inducing texture in oxide superconductors has been the epitaxial growth of films on rolling-assisted biaxially-textured substrates (RABiTS) [3]. In this approach, rolled Ni foils are recrystallized under conditions that lead to a high degree of biaxial {l_brace}001{r_brace} cube texture. Subsequent deposition of epitaxial oxide buffer layers (typically CeO{sub 2} and YSZ as chemical barriers) and superconducting YBCO preserves the lattice alignment, eliminating high-angle boundaries and enabling high critical current densities, J{sub c} > 10{sup 6}/cm{sup 2}. Conventional x-ray diffraction using {omega}- and {phi}-scans typically shows macroscopic biaxial texture to within {approx}5{sup o}-10{sup o} FWHM for all layers, but does not describe the local microstructural features that control the materials properties. Understanding and controlling the local texture and microstructural evolution of processes associated with heteroepitaxial growth, differential thermal contraction and cracking remain significant challenges in this complex system [4], as well as in many other technologically important thin-film applications.
Fundamental studies of the mechanism of catalytic reactions with catalysts effective in the gasification of carbon solids and the oxidative coupling of methane. Quarterly report, January 1, 1995--March 31, 1995
The synthesis of ethane and ethylene from methane and oxygen will be carried out in novel hydrogen transport inorganic membranes and in cyclic reactors in order to prevent undesirable secondary reactions of C{sub 2} molecules to CO and CO{sub 2}. Neither inorganic membrane reactors nor cyclic tubular reactors are presently used in commercial processes. Their application to catalytic reactions represents a novel application of engineering and solid-state chemistry concepts to catalytic reactions. Our approach combines high temperature membrane and cyclic experimental reactors, synthesis and characterization of thin membrane films and of high surface area catalysts, and detailed models of complex gas phase and surface reactions involved in oxidative coupling. We anticipate that this approach will lead to novel reactors for carrying our kinetic-controlled sequential reactions, such as the oxidative coupling of methane. Careful spectrographic and wet chemical analyses of fresh and silent catalysts have shown considerable differences which have permitted conclusions as to the source of deactivation. Our activities in the first quarter FYI 995 have focused on the synthesis, structural characterization, and catalytic evaluation of membrane films, disks, and reactors. We have also continued to exploit reaction-transport models to predict the performance of membrane, cyclic, and recycle reactors in the oxidative coupling of methane.
Mechanism of the Initial Oxidation of Hydrogen andHalogen Terminated Ge(111) Surfaces in Air
The initial stage of the oxidation of Ge(111) surfaces etched by HF, HCl and HBr solutions is systematically studied using synchrotron radiation photoelectron spectroscopy (SR-PES). We perform controlled experiments to differentiate the effects of different oxidation factors. SR-PES results show that both moisture and oxygen contribute to the oxidation of the surfaces; however, they play different roles in the oxidation process. Moisture effectively replaces the hydrogen and halogen termination layers with hydroxyl (OH), but hardly oxidizes the surfaces further. On the other hand, dry oxygen does not replace the termination layers, but breaks the Ge-Ge back bonds and oxidizes the substrates with the aid of moisture. In addition, room light enhances the oxidation rate significantly.
Sun, Shiyu; /Stanford U., Phys. Dept.; Sun, Yun; Liu, Zhi; Lee, Dong-Ick; Pianetta, Piero; /SLAC, SSRL
Nanostructured Metal Oxide Anodes (Presentation)
This summarizes NREL's FY09 battery materials research activity in developing metal oxide nanostructured anodes to enable high-energy, durable and affordable li-ion batteries for HEVs and PHEVs.
Dillon, A. C.; Riley, L. A.; Lee, S.-H.; Kim, Y.-H.; Ban, C.; Gillaspie, D. T.; Pesaran, A.
A process of volatilizing fissionable material away from fission products, present together in neutron-bombarded uranium oxide, by reaction with an oxygen-fluorine mixture at 350 to 500 deg C is described. (AEC)
Mecham, W.J.; Gabor, J.D.
Oxides having high energy densities
Certain disclosed embodiments generally relate to oxide materials having relatively high energy and/or power densities. Various aspects of the embodiments are directed to oxide materials having a structure B.sub.i(M.sub.jY.sub.k)O.sub.2, for example, a structure Li.sub.j(Ni.sub.jY.sub.k)O.sub.2 such as Li(Ni.sub.0.5Mn.sub.0.5)O.sub.2. In this structure, Y represents one or more atoms, each independently selected from the group consisting of alkaline earth metals, transition metals, Group 14 elements, Group 15, or Group 16 elements. In some embodiments, such an oxide material may have an O3 crystal structure, and/or a layered structure such that the oxide comprises a plurality of first, repeating atomic planes comprising Li, and a plurality of second, repeating atomic planes comprising Ni and/or Y.
Ceder, Gerbrand; Kang, Kisuk
Process for light-driven hydrocarbon oxidation at ambient temperatures
A photochemical reaction for the oxidation of hydrocarbons uses molecular oxygen as the oxidant. A reductive photoredox cycle that uses a tin(IV)- or antimony(V)-porphyrin photosensitizer generates the reducing equivalents required to activate oxygen. This artificial photosynthesis system drives a catalytic cycle, which mimics the cytochrome P.sub.450 reaction, to oxidize hydrocarbons. An iron(III)- or manganese(III)-porphyrin is used as the hydrocarbon-oxidation catalyst. Methylviologen can be used as a redox relay molecule to provide for electron-transfer from the reduced photosensitizer to the Fe or Mn porphyrin. The system is long-lived and may be used in photo-initiated spectroscopic studies of the reaction to determine reaction rates and intermediates.
Shelnutt, John A. (Tijeras, NM)
A photochemical reaction for the oxidation of hydrocarbons uses molecular oxygen as the oxidant. A reductive photoredox cycle that uses a tin(IV)- or antimony(V)-porphyrin photosensitizer generates the reducing equivalents required to activate oxygen. This artificial photosynthesis system drives a catalytic cycle, which mimics the cytochrome P{sub 450} reaction, to oxidize hydrocarbons. An iron(III)- or manganese(III)-porphyrin is used as the hydrocarbon-oxidation catalyst. Methylviologen can be used as a redox relay molecule to provide for electron-transfer from the reduced photosensitizer to the Fe or Mn porphyrin. The system is long-lived and may be used in photo-initiated spectroscopic studies of the reaction to determine reaction rates and intermediates. 1 fig. 2 tab.
Shelnutt, J.A.
Emergent Phenomena at Oxide Interfaces
Transition metal oxides (TMOs) are an ideal arena for the study of electronic correlations because the s-electrons of the transition metal ions are removed and transferred to oxygen ions, and hence the strongly correlated d-electrons determine their physical properties such as electrical transport, magnetism, optical response, thermal conductivity, and superconductivity. These electron correlations prohibit the double occupancy of metal sites and induce a local entanglement of charge, spin, and orbital degrees of freedom. This gives rise to a variety of phenomena, e.g., Mott insulators, various charge/spin/orbital orderings, metal-insulator transitions, multiferroics, and superconductivity. In recent years, there has been a burst of activity to manipulate these phenomena, as well as create new ones, using oxide heterostructures. Most fundamental to understanding the physical properties of TMOs is the concept of symmetry of the order parameter. As Landau recognized, the essence of phase transitions is the change of the symmetry. For example, ferromagnetic ordering breaks the rotational symmetry in spin space, i.e., the ordered phase has lower symmetry than the Hamiltonian of the system. There are three most important symmetries to be considered here. (i) Spatial inversion (I), defined as r {yields} -r. In the case of an insulator, breaking this symmetry can lead to spontaneous electric polarization, i.e. ferroelectricity, or pyroelectricity once the point group belongs to polar group symmetry. (ii) Time-reversal symmetry (T) defined as t {yields} -t. In quantum mechanics, the time-evolution of the wave-function {Psi} is given by the phase factor e{sup -iEt/{h_bar}} with E being the energy, and hence time-reversal basically corresponds to taking the complex conjugate of the wave-function. Also the spin, which is induced by the 'spinning' of the particle, is reversed by time-reversal. Broken T-symmetry is most naturally associated with magnetism, since the spin operator changes sign with T-operation. (iii) Gauge symmetry (G), which is associated with a change in the phase of the wave-function as {Psi} {yields} e{sup i{theta}}{Psi}. Gauge symmetry is connected to the law of charge conservation, and broken G-symmetry corresponds to superconductivity/superfluidity. To summarize, the interplay among these electronic degrees of freedom produces various forms of symmetry breaking patterns of I, T, and G, leading to novel emergent phenomena, which can appear only by the collective behavior of electrons and cannot be expected from individual electrons. Figure 1 shows this schematically by means of several representative phenomena. From this viewpoint, the interfaces of TMOs offer a unique and important laboratory because I is already broken by the structure itself, and the detailed form of broken I-symmetry can often be designed. Also, two-dimensionality usually enhances the effects of electron correlations by reducing their kinetic energy. These two features of oxide interfaces produce many novel effects and functions that cannot be attained in bulk form. Given that the electromagnetic responses are a major source of the physical properties of solids, and new gauge structures often appear in correlated electronic systems, we put 'emergent electromagnetism' at the center of Fig. 1.
Hwang, H.Y.
Dissolution of Technetium(IV) Oxide by Natural and Synthetic Organic Ligands Under both Reducing and Oxidizing Conditions
Technetium-99 (Tc) in nuclear waste is a significant environmental concern due to its long half-life and high mobility in the subsurface. Reductive precipitation of Tc(IV) oxides [TcO2(s)] is an effective means of immobilizing Tc, thereby impeding its migration in groundwater. However, TcO2(s) is subject to dissolution by oxidants and/or complexing agents. In this study we ascertain the effects of a synthetic organic ligand, ethylenediaminetetraacetate (EDTA), and two natural humic isolates on the dissolution and solubility of Tc(IV) oxides. Pure synthetic TcO2(s) (0.23 mM) was used in batch experiments to determine dissolution kinetics at pH ~6 under both reducing and oxidizing conditions. All organic ligands were found to enhance the dissolution of Tc(IV) oxides, increasing their solubility from ~10-8 M (without ligands) to 4 10-7 M under strictly anoxic conditions. Reduced Tc(IV) was also found to re-oxidize rapidly under oxic conditions, with an observed oxidative dissolution rate approximately an order of magnitude higher than that of ligand-promoted dissolution under reducing conditions. Significantly, oxidative dissolution was inhibited by EDTA but enhanced by humic acid compared with experiments without any complexing agents. The redox functional properties of humics, capable of facilitating intra-molecular electron transfer, may account for this increased oxidation rate under oxic conditions. Our results highlight the importance of complex interactions for the stability and mobility of Tc, and thus for the long-term fate of Tc in contaminated environments.
Gu, Baohua [ORNL; Dong, W. [Lawrence Berkeley National Laboratory (LBNL); Liang, Liyuan [ORNL; Wall, Nathalie [Washington State University
Millisecond Oxidation of Alkanes
This project was undertaken in response to the Department of Energy's call to research and develop technologies 'that will reduce energy consumption, enhance economic competitiveness, and reduce environmental impacts of the domestic chemical industry.' The current technology at the time for producing 140 billion pounds per year of propylene from naphtha and Liquified Petroleum Gas (LPG) relied on energy- and capital-intensive steam crackers and Fluidized Catalytic Cracking (FCC) units. The propylene is isolated from the product stream in a costly separation step and subsequently converted to acrylic acid and other derivatives in separate production facilities. This project proposed a Short Contact Time Reactor (SCTR)-based catalytic oxydehydrogenation process that could convert propane to propylene and acrylic acid in a cost-effective and energy-efficient fashion. Full implementation of this technology could lead to sizeable energy, economic and environmental benefits for the U. S. chemical industry by providing up to 45 trillion BTUs/year, cost savings of $1.8 billion/year and a combined 35 million pounds/year reduction in environmental pollutants such as COx, NOx, and SOx. Midway through the project term, the program directive changed, which approval from the DOE and its review panel, from direct propane oxidation to acrylic acid at millisecond contact times to a two-step process for making acrylic acid from propane. The first step was the primary focus, namely the conversion of propane to propylene in high yields assisted by the presence of CO2. The product stream from step one was then to be fed directly into a commercially practiced propylene-to-acrylic acid tandem reactor system.
Scott Han
SoS Minerals Expert Group Science and Implementation Plan
resources, including wind and solar; a growth in the use electric and hybrid vehicles; and increasing energy of these minerals and elements, governed by the imperative to decrease environmental impact. Figure 1 Historical compounded by low substitutability and recycling rates (commonly
Brierley, Andrew
`Save Our Squirrels' (SOS) A Red Alert North England Project
red squirrel range in northern England. ┬Ę Construction of new viewing facilities at Sefton, Whinlatter, involved and supportive. ┬Ę It is essential to start by preparing a clear strategy that all the key
Comparing SOS and SDP relaxations of sensor network localization
Jan 18, 2010 ... where U = ( uij. ) 1?i,j?m and ... they give the same set of Z. However, this latter approach may recover sen- .... Since there are only two sen-.
A convex polynomial that is not sos-convex
Mar 6, 2009 ... Sympos. Wright-. Patterson Air Force Base, Ohio, 1965), pages 205¢224. Academic Press, New York, 1967. [17] K. G. Murty and S. N. Kabadi.
SOS: saving time in dynamic race detection with stationary analysis
Data races are subtle and difficult to detect errors that arise during concurrent program execution. Traditional testing techniques fail to find these errors, but recent research has shown that targeted dynamic analysis techniques can be developed to ... Keywords: concurrency, monitoring, race, threading
Du Li; Witawas Srisa-an; Matthew B. Dwyer
Novel metalloporphyrin catalysts for the oxidation of hydrocarbons
Work was done for developing biomimetic oxidation catalysts. Two classes of metalloporphyrin catalysts were studied. The first class of catalysts studied were a novel series of highly substituted metalloporphyrins, the fluorinated iron dodecaphenylporphyrins. These homogeneous metalloporphyrin catalysts were screened for activity as catalysts in the oxidation of hydrocarbons by dioxygen. Results are discussed with respect to catalyst structural features. The second type of catalysts studied were heterogeneous catalysts consisting of metalloporphyrins applied to inorganic supports. Preliminary catalytic testing results with these materials are presented.
Showalter, M.C.; Nenoff, T.M.; Shelnutt, J.A.
Reduction of Metal Oxide to Metal using Ionic Liquids
A novel pathway for the high efficiency production of metal from metal oxide means of electrolysis in ionic liquids at low temperature was investigated. The main emphasis was to eliminate the use of carbon and high temperature application in the reduction of metal oxides to metals. The emphasis of this research was to produce metals such as Zn, and Pb that are normally produced by the application of very high temperatures. The reduction of zinc oxide to zinc and lead oxide to lead were investigated. This study involved three steps in accomplishing the final goal of reduction of metal oxide to metal using ionic liquids: 1) Dissolution of metal oxide in an ionic liquid, 2) Determination of reduction potential using cyclic voltammetry (CV) and 3) Reduction of the dissolved metal oxide. Ionic liquids provide additional advantage by offering a wide potential range for the deposition. In each and every step of the process, more than one process variable has been examined. Experimental results for electrochemical extraction of Zn from ZnO and Pb from PbO using eutectic mixtures of Urea ((NH2)2CO) and Choline chloride (HOC2H4N(CH3)3+Cl-) or (ChCl) in a molar ratio 2:1, varying voltage and temperatures were carried out. Fourier Transform Infra-Red (FTIR) spectroscopy studies of ionic liquids with and without metal oxide additions were conducted. FTIR and induction coupled plasma spectroscopy (ICPS) was used in the characterization of the metal oxide dissolved ionic liquid. Electrochemical experiments were conducted using EG&G potentiostat/galvanostat with three electrode cell systems. Cyclic voltammetry was used in the determination of reduction potentials for the deposition of metals. Chronoamperometric experiments were carried out in the potential range of -0.6V to -1.9V for lead and -1.4V to -1.9V for zinc. The deposits were characterized using XRD and SEM-EDS for phase, morphological and elemental analysis. The results showed that pure metal was deposited on the cathode. Successful extraction of metal from metal oxide dissolved in Urea/ChCl (2:1) was accomplished. The current efficiencies were relatively high in both the metal deposition processes with current efficiency greater than 86% for lead and 95% for zinc. This technology will advance the metal oxide reduction process by increasing the process efficiency and also eliminate the production of CO2 which makes this an environmentally benign technology for metal extraction.
Dr. Ramana Reddy
Process for fabrication of metal oxide films
This invention is comprised of a method of fabricating metal oxide films from a plurality of reactants by inducing a reaction by plasma deposition among the reactants. The plasma reaction is effective for consolidating the reactants and producing thin films of metal oxides, e.g. electro-optically active transition metal oxides, at a high deposition rate. The presence of hydrogen during the plasma reaction enhances the deposition rate of the metal oxide. Various types of metal oxide films can be produced.
Tracy, C.E.; Benson, D.; Svensson, S.
Soil¢Atmosphere Exchange of Nitrous Oxide, Nitric Oxide, Methane, and Carbon Dioxide in Logged and Undisturbed Forest in the Tapajos National Forest, Brazil
Selective logging is an extensive land use in the Brazilian Amazon region. The soil¢atmosphere fluxes of nitrous oxide (N2O), nitric oxide (NO), methane (CH4), and carbon dioxide (CO2) are studied on two soil types (clay Oxisol and sandy loam ...
Michael Keller; Ruth Varner; Jadson D. Dias; Hudson Silva; Patrick Crill; Raimundo Cosme de Oliveira Jr.; Gregory P. Asner
Multimetal Oxide Thin Films
... as substrates for detailed studies of reaction mechanisms and kinetics with gases involved in catalyzed reactions as methane coupling and coal gasification; ...
Coupling of oxidative dehydrogenation and aromatization reactions of butane
Coupling of oxidative dehydrogenation and aromatization of butane by using a dual function catalyst has led to a significant enhancement of the yields (from 25 to 40%) and selectivities to aromatics (from 39 to 64%). Butane is converted to aromatics by using either zinc-promoted [Ga]-ZSM-5 or zinc and gallium copromoted [Fe]-ZSM-5 zeolite as a catalyst. However, the formation of aromatics is severely limited by hydrocracking of butane to methane, ethane, and propane due to the hydrogen formed during aromatization reactions. On the other hand, the oxidative dehydrogenation of butane to butene over molybdate catalysts is found to be accompanied by a concurrent undesirable reaction, i.e., total oxidation. When two of these reactions (oxidative dehydrogenation and aromatization of butane) are coupled by using a dual function catalyst they have shown to complement each other. It is believed that the rate-limiting step for aromatization (butane to butene) is increased by adding an oxidative dehydrogenation catalyst (Ga-Zn-Mg-Mo-O). The formation of methane, ethane, and propane was suppressed due to the removal of hydrogen initially formed as water. Studies of ammonia TPD show that the acidities of [Fe]-ZSM-5 are greatly affected by the existence of metal oxides such as Ga[sub 2]O[sub 3], MgO, ZnO, and MoO[sub 3]. 40 refs., 9 figs., 1 tab.
Xu, Wen-Qing; Suib, S.L. (Univ. of Connecticut, Storrs, CT (United States))
Mechanistic aspects of photooxidation of polyhydroxylated molecules on metal oxides.
Polyhydroxylated molecules, including natural carbohydrates, are known to undergo photooxidation on wide-gap transition-metal oxides irradiated by ultraviolet light. In this study, we examine mechanistic aspects of this photoreaction on aqueous TiO{sub 2}, {alpha}-FeOOH, and {alpha}-Fe{sub 2}O{sub 3} particles using electron paramagnetic resonance (EPR) spectroscopy and site-selective deuteration. We demonstrate that the carbohydrates are oxidized at sites involved in the formation of oxo bridges between the chemisorbed carbohydrate molecule and metal ions at the oxide surface. This bridging inhibits the loss of water (which is the typical reaction of the analogous free radicals in bulk solvent) promoting instead a rearrangement that leads to elimination of the formyl radical. For natural carbohydrates, the latter reaction mainly involves carbon-1, whereas the main radical products of the oxidation are radical arising from H atom loss centered on carbon-1, -2, and -3 sites. Photoexcited TiO{sub 2} oxidizes all of the carbohydrates and polyols, whereas {alpha}-FeOOH oxidizes some of the carbohydrates, and {alpha}-Fe{sub 2}O{sub 3} is unreactive. These results serve as a stepping stone for understanding the photochemistry on mineral surfaces of more complex biomolecules such as nucleic acids.
Shkrob, I. A.; Marin, T. M.; Sevilla, M. D.; Chemerisov, S. (Chemical Sciences and Engineering Division); (Benedictine Univ.); (Oakland Univ.)
Catalytic hydrocarbon reactions over supported metal oxides. Progress report, April 1, 1994--January 31, 1995
Oxide catalysis plays a central role in hydrocarbon processing and improvements in catalytic activity or selectivity are of great technological importance because these improvements will translate directly into more efficient utilization of hydrocarbon supplies and lower energy consumption in separation processes. An understanding of the relationships between surface structure and catalytic properties is needed to describe and improve oxide catalysts. Our approach has been to prepare supported oxides that have a specific structure and oxidation state and then employ these structures in reaction studies. Our current research program is focused on studying the fundamental relationships between structure and reactivity for two important reactions that are present in many oxide-catalyzed processes, partial oxidation and carbon-carbon bond formation. Oxide catalysis can be a complex process with both metal cation and oxygen anions participating in the chemical reactions. From an energy perspective carbon-carbon bond formation is particularly relevant to CO hydrogenation in isosynthesis. Hydrogenolysis and hydrogenation form the basis for heteroatom removal in fuels processing. Understanding the catalysis of these processes (and others) requires isolating reaction steps in the overall cycle and determining how structure and composition influence the individual reaction steps. Specially designed oxides, such as we use, permit one to study some of the steps in oxidation, carbon-carbon coupling and heteroatom removal catalysis. During the course of our studies we have: (1) developed methods to form and stabilize various Mo and W oxide structures on silica; (2) studied C-H abstraction reactions over the fully oxidized cations; (3) studied C-C bond coupling by methathesis and reductive coupling of aldehydes and ketones over reduced cation structures; and (4) initiated a study of hydrogenation and hydrogenolysis over reduced cation structures.
Lipid Oxidation Pathways, Volume 2Chapter 3 Oxidation of Long-Chain Polyunsaturated Fatty Acids
Lipid Oxidation Pathways, Volume 2 Chapter 3 Oxidation of Long-Chain Polyunsaturated Fatty Acids Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf of Chapter 3 Oxid
Analysis of Lipid OxidationChapter 10 Kinetic Analysis of Lipid Oxidation Data
Analysis of Lipid Oxidation Chapter 10 Kinetic Analysis of Lipid Oxidation Data Methods and Analyses eChapters Methods - Analyses Books Downloadable pdf of Chapter 10 Kinetic Analysis of Lipid Oxidation Data from ...
Analysis of Lipid OxidationChapter 1 Lipid Oxidation Products and Methods Used for Their Analysis
Analysis of Lipid Oxidation Chapter 1 Lipid Oxidation Products and Methods Used for Their Analysis Methods and Analyses eChapters Methods - Analyses Books AOCS Press Downloadable pdf of Chapter 1 Lipid Oxidation P
Analysis of Lipid OxidationChapter 2 Volumetric Analysis of Oxidized Lipids
Analysis of Lipid Oxidation Chapter 2 Volumetric Analysis of Oxidized Lipids Methods and Analyses eChapters Methods - Analyses Books AOCS Press Downloadable pdf of Chapter 2 Volumetric Analysis of Oxidized Lipids
Analysis of Lipid OxidationChapter 6 Analysis of Lipid Oxidation by ESR Spectroscopy
Analysis of Lipid Oxidation Chapter 6 Analysis of Lipid Oxidation by ESR Spectroscopy Methods and Analyses eChapters Methods - Analyses Books Downloadable pdf of Chapter 6 Analysis of Lipid Oxidation by ESR Spectrosco
Lipid Oxidation PathwaysChapter 2 Oxidation of Fish Lipids and Its Inhibition with Tocopherolsh
Lipid Oxidation Pathways Chapter 2 Oxidation of Fish Lipids and Its Inhibition with Tocopherolsh Processing eChapters Processing Press Downloadable pdf of Chapter 2 Oxidation of Fish Lipids and Its Inhibition with
Solid oxide fuel cell combined cycles
The integration of the solid oxide fuel cell and combustion turbine technologies can result in combined-cycle power plants, fueled with natural gas, that have high efficiencies and clean gaseous emissions. Results of a study are presented in which conceptual designs were developed for 3 power plants based upon such an integration, and ranging in rating from 3 to 10 MW net ac. The plant cycles are described and characteristics of key components summarized. Also, plant design-point efficiency estimates are presented as well as values of other plant performance parameters.
Bevc, F.P. [Westinghouse Electric Corp., Orlando, FL (United States). Power Generation Business Unit; Lundberg, W.L.; Bachovchin, D.M. [Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center
The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.
Ballard, Ambrose H. (Oak Ridge, TN); Godfrey, Jr., Thomas G. (Oak Ridge, TN); Mowery, Erb H. (Clinton, TN)
Biomimetic oxidation studies. 11: Alkane functionalization in aqueous solution utilizing in situ formed [Fe{sub 2}O({eta}{sup 1}-H{sub 2}O)({eta}{sup 1}-OAc)(TPA){sub 2}]{sup 3+}, as an MMO model precatalyst, embedded in surface-derivatized silica and contained in micelles
The biomimetic, methane monooxygenase enzyme (MMO) precatalyst, [Fe{sub 2}O({eta}{sup 1}-H{sub 2}O)({eta}{sup 1}-OAc)(TPA){sub 2}]{sup 3+} (TPA = tris[(2-pyridyl)methyl]amine), 1, formed in situ at pH 4.2 from [Fe{sub 2}O({mu}-OAc)(TPA){sub 2}]{sup 3+}, 2, was embedded in an amorphous silicate surface modified by a combination of hydrophilic poly(ethylene oxide) and hydrophobic poly(propylene oxide). The resulting catalytic assembly was found to be a biomimetic model for the MMO active site within a hydrophobic macroenvironment, allowing alkane functionalization with tert-butyl hydroperoxide (TBHP)/O{sub 2} in an aqueous reaction medium (pH 4.2). For example, cyclohexane was oxidized to a mixture of cyclohexanone, cyclohexanol, and cyclohexyl-tert-butyl peroxide, in a ratio of {approximately}3:1:2. The balance between poly(ethylene oxide) and poly(propylene oxide), tethered on the silica surface, was crucial for maximizing the catalytic activity. The silica-based catalytic assembly showed reactivity somewhat higher in comparison to an aqueous micelle system utilizing the surfactant, cetyltrimethylammonium hydrogen sulfate at its critical micelle concentration, in which functionalization of cyclohexane with TBHP/O{sub 2} in the presence of 1 was also studied at pH 4.2 and was found to provide similar products: cyclohexanol, cyclohexanone, and cyclohexyl-tert-butyl peroxide, in a ratio of {approximately}2:3:1. Moreover, the mechanism for both the silica-based catalytic assembly and the aqueous micelle system was found to occur via the Haber-Weiss process, in which redox chemistry between 1 and TBHP provides both the t-BuO{sup {sm_bullet}} and t-BuOO{sup {sm_bullet}} radicals. The t-BuO{sup {sm_bullet}} radical initiates the C-H functionalization reaction to form the carbon radical, followed by O{sub 2} trapping, to provide cyclohexyl hydroperoxide, which produces the cyclohexanol and cyclohexanone in the presence of 1, whereas the coupling product emanates from t-BuOO{sup {sm_bullet}} and cyclohexyl radicals. A discussion concerning both approaches for alkane functionalization in water will be presented.
Neimann, K.; Neumann, R. [Hebrew Univ., Jerusalem (Israel); Rabion, A. [Lawrence Berkeley National Lab., CA (United States)]|[Groupement de Recherche de Lacq, Artix (France); Buchanan, R.M. [Univ. of Louisville, KY (United States). Dept. of Chemistry; Fish, R.H. [Lawrence Berkeley National Lab., CA (United States)
A method is given for preparing uranium dioxide, thorium oxide, and beryllium oxide in the form of enlarged individual crystals. The surface of a fused alkali metal halide melt containing dissolved uranium, thorium, or beryllium values is contacted with a water-vapor-bearing inert gas stream at a rate of 5 to 10 cubic centimeters per minute per square centimeter of melt surface area. Growth of individual crystals is obtained by prolonged contact. Beryllium oxide-coated uranium dioxide crystals are prepared by disposing uranium dioxide crystals 5 to 20 microns in diameter in a beryllium-containing melt and contacting the melt with a water-vapor-bearing inert gas stream in the same manner. (AEC)
Grimes, W.R.; Shaffer, J.H.; Watson, G.M.
Oxidants, Antioxidants and Cell Signaling
Oxidants, Antioxidants and Cell Signaling Oxidants, Antioxidants and Cell Signaling Speaker(s): Chandan K. Sen Date: February 17, 1998 - 12:00pm Location: 90-3148 Seminar Host/Point of Contact: Richard Sextro Reactive oxygen species represent a common mediator of environmental stress such as during physical exercise, ozone exposure, UV radiation and xenobiotic (pollutant) metabolism. Antioxidant defense systems protect against the ravages of such reactive species. In contrast to the conventional idea that reactive oxygen is mostly a trigger for oxidative damage of biological structures, now we know that low physiologically relevant concentration of reactive oxygen species can regulate a variety of key molecular mechanisms that may be linked with important processes such as immune response, cell-cell adhesion, cell proliferation, inflammation,
Adsorption of Propane on the Magnesium Oxide (100) Surface and Synthesis of Anodized Aluminum Oxide.
??This work is divided into two parts: the adsorption of propane on the magnesium oxide (100) surface and the synthesis of anodized aluminum oxide. Theģ (more)
Felty, Michael John
Cholesterol and Phytosterol Oxidation ProductsChapter 14 Cholesterol Oxidation Products: Other Biological Effects
Cholesterol and Phytosterol Oxidation Products Chapter 14 Cholesterol Oxidation Products: Other Biological Effects Food Science Health Nutrition Biochemistry eChapters Food Science & Technology Health - Nutrition - Biochemistry Press
Cholesterol and Phytosterol Oxidation ProductsChapter 13 Cholesterol Oxidation Products and Atherosclerosis
Cholesterol and Phytosterol Oxidation Products Chapter 13 Cholesterol Oxidation Products and Atherosclerosis Food Science Health Nutrition Biochemistry eChapters Food Science & Technology Health - Nutrition - Biochemistry Press ...
Cholesterol and Phytosterol Oxidation ProductsChapter 1 Cholesterol Oxidation Mechanisms
Cholesterol and Phytosterol Oxidation Products Chapter 1 Cholesterol Oxidation Mechanisms Food Science Health Nutrition Biochemistry eChapters Food Science & Technology Health - Nutrition - Biochemistry Press Ā ...
Cholesterol and Phytosterol Oxidation ProductsChapter 6 Harmonization of Cholesterol Oxidation Product Analysis
Cholesterol and Phytosterol Oxidation Products Chapter 6 Harmonization of Cholesterol Oxidation Product Analysis Food Science Health Nutrition Biochemistry eChapters Food Science & Technology Health - Nutrition - Biochemistry Press
Solid oxide fuel cell generator
A solid oxide fuel cell generator has a pair of spaced apart tubesheets in a housing. At least two intermediate barrier walls are between the tubesheets and define a generator chamber between two intermediate buffer chambers. An array of fuel cells have tubes with open ends engaging the tubesheets. Tubular, axially elongated electrochemical cells are supported on the tubes in the generator chamber. Fuel gas and oxidant gas are preheated in the intermediate chambers by the gases flowing on the other side of the tubes. Gas leakage around the tubes through the tubesheets is permitted. The buffer chambers reentrain the leaked fuel gas for reintroduction to the generator chamber.
Draper, Robert (Churchill Boro, PA); George, Raymond A. (Pittsburgh, PA); Shockling, Larry A. (Plum Borough, PA)
Lipid Oxidation and Quality Division April 2013 Newsletter
Read the Lipid Oxidation and Quality Division April 2013 Newsletter Lipid Oxidation and Quality Division April 2013 Newsletter Lipid Oxidation and Quality Division ...
Lipid Oxidation and Quality Division July 201/span>3 Newsletter
Read the Lipid Oxidation and Quality Division July 201/span>3 Newsletter Lipid Oxidation and Quality Division July 201/span>3 Newsletter Lipid Oxidation and Quality Division ...
Argonne CNM News: Hollow Iron Oxide Nanoparticles for Lithium...
Hollow Iron Oxide Nanoparticles for Lithium-Ion Battery Applications Hollow iron oxide nanoparticles Transmission electron micrograph of hollow iron oxide nanoparticles....
Formulations for iron oxides dissolution
A mixture of a di- or polyphosphonic acid and a reductant wherein each is present in a sufficient amount to provide a synergistic effect with respect to the dissolution of metal oxides and optionally containing corrosion inhibitors and pH adjusting agents.
Horwitz, Earl P. (Argonne, IL); Chiarizia, Renato (Argonne, IL)
Machinable dissolved metal oxide superconductors
Powders of a metal oxide superconductor are mixed with sufficient amount (10--80 mol%) of In, Sn, and/or Al, to become nonbrittle, machinable. Preferred superconductors are YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} and Bi-Sr-Ca-Cu-O compounds.
Chen, Chung-Hsuan
Powders of a metal oxide superconductor are mixed with sufficient amount (10--80 mol%) of In, Sn, and/or Al, to become nonbrittle, machinable. Preferred superconductors are YBa[sub 2]Cu[sub 3]O[sub 7[minus]x] and Bi-Sr-Ca-Cu-O compounds.
Chen, Chung-Hsuan.
A solid oxide fuel cell generator has a plenum containing at least two rows of spaced apart, annular, axially elongated fuel cells. An electrical conductor extending between adjacent rows of fuel cells connects the fuel cells of one row in parallel with each other and in series with the fuel cells of the adjacent row.
Di Croce, A. Michael (Murrysville, PA); Draper, Robert (Churchill Boro, PA)
Lipid Oxidation and Quality Division
Name AffiliationCity, State, CountryLipid Oxidation & Quality Division2013 Members327 Members as of October 1, 2013, Process Plus LLCCincinnati, OH, USAAbraham, TimothyCargill IncHopkins, MN, USAAbrams, JimCargill Corn Milling NAMemphis, TN, USAAbril, Rube
Perovskite catalysts for oxidative coupling
Perovskites of the structure A[sub 2]B[sub 2]C[sub 3]O[sub 10] are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.
Campbell, K.D.
A solid oxide fuel cell generator has a plenum containing at least two rows of spaced apart, annular, axially elongated fuel cells. An electrical conductor extending between adjacent rows of fuel cells connects the fuel cells of one row in parallel with each other and in series with the fuel cells of the adjacent row. 5 figures.
Di Croce, A.M.; Draper, R.
Screening of cosurfactant-free slugs: Project BE4A, milestone 12, FY87: Topical report. [Amine oxides
This report describes our initial work with amine oxides as surfactants for chemical flooding. Our work on carboxymethylated ethoxylates was previously reported in NIPER-228. Amine oxides have high salinity range, yield low interfacial tensions, have high solubilization parameters, and, at the same time, increase the viscosity of the surfactant slug without the addition of polymer, and thus avoiding problems caused by surfactant - polymer interactions. The oil displacement results reported incorporate alcohol as a cosurfactant in the amine oxide formulations, however, compounds that attempt to incorporate the cosolvent moiety into the amine oxide molecule (ethoxylated or propoxylated amine oxides) are being studied at NIPER. 60 refs., 4 tabs.
Olsen, D.K.
Complex oxides useful for thermoelectric energy conversion
The invention provides for a thermoelectric system comprising a substrate comprising a first complex oxide, wherein the substrate is optionally embedded with a second complex oxide. The thermoelectric system can be used for thermoelectric power generation or thermoelectric cooling.
Majumdar, Arunava (Orinda, CA); Ramesh, Ramamoorthy (Moraga, CA); Yu, Choongho (College Station, TX); Scullin, Matthew L. (Berkeley, CA); Huijben, Mark (Enschede, NL)
Lipid Oxidation and Quality Division Poster Competition
Lipid Oxidation and Quality Division student award for best poster presentation at the AOCS Annual Meeting & Expo. Lipid Oxidation and Quality Division Poster Competition Divisions achievement agricultural analytical application award awards biote
Nanostructured Solid Oxide Fuel Cell Electrodes
in Solid Oxide Fuel Cells (SOFC IX), S. C. Singhal and J.create connected nanostructured SOFC electrodes is reviewed.of Solid Oxide Fuel Cells (SOFC) to directly and efficiently
Sholklapper, Tal Zvi
Lipid Oxidation: Challenges in Food Systems
Lipid oxidation in food systems is one of the most important factors which affect food quality, nutrition, safety, color and consumersÆ acceptance. Lipid Oxidation: Challenges in Food Systems Health acid analysis aocs april articles chloropropanediol con
Genomic consequences of DNA oxidation by peroxynitrite
The radicals nitric oxide and superoxide are produced endogenously by activated macrophages and neutrophils and combine in a diffusion-limited reaction to form peroxynitrite, a powerful oxidizing and nitrating agent capable ...
Neeley, William Louis
post-Doping of Solid Oxide Fuel Cell Cathodes,? P.h.D.and Technology of Ceramic Fuel Cells, p. 209, Elsevier, NewI. Birss, in Solid Oxide Fuel Cells (SOFC IX), S. C. Singhal
Production of Organic Oxygenates in the Partial Oxidation of Methane in a Silent Electric Discharge Reactor
Significant amounts of these reserves are located in remote areas. Steam reforming to synthesis gasProduction of Organic Oxygenates in the Partial Oxidation of Methane in a Silent Electric Discharge, Room T 335, Norman, Oklahoma 73019 This study on the partial oxidation of methane in a silent electric
Mallinson, Richard
Defect gap states on III-V semiconductor-oxide interfaces (invited)
Interfaces models of (100)GaAs and various high K oxides such as HfO"2, Gd"2O"3 or Al"2O"3 are used to study the interfacial defects and mis-bonded sites which can introduce states into the semiconductor gap, and cause the Fermi level pinning observed ... Keywords: Calculation, FET, GaAs, Interface states, Oxide, Passivation
J. Robertson; L. Lin
Length scales for coherent ?-bonding interactions in complex high-k oxide dielectrics and their interfaces
This paper uses X-ray absorption and vacuum ultra-violet spectroscopic ellipsometry to distinguish between non-crystallinity, and the suppression of Jahn-Teller splittings that identify a scale of order metric, @l"s, of ~3 nm for distinguishing between ... Keywords: Length scales of order, Nanocrystalline complex oxides and complex oxide alloys, Spectroscopic studies
H. Seo; G. Lucovsky; L. B. Fleming; M. D. Ulrich; J. L³ning; G. Koster; T. H. Geballe
Improved Prediction of Nitrogen Oxides Using GRNN with K-Means Clustering and EDA
The current study presented a generalized regression neural network (GRNN) based approach to predict nitrogen oxides (NOx) emitted from coal-fired boiler. A novel 'multiple' smoothing parameters, which is different from the standard algorithm in which ... Keywords: GRNN, EDA, K-means Clustering, Nitrogen Oxides, Power plants
Ligang Zheng; Shuijun Yu; Wei Wang; Minggao Yu
Porous iron and ferric oxide pellets for hydrogen storage: texture and transport characteristics
Materials for hydrogen storage based on the recovery reduction of Fe3O4 to iron and back iron oxidation to Fe3O4 by water vapor were studied. The preparation conditions for cylindrical pellets from ferric oxide/aluminium ... Keywords: hydrogen storage, inverse gas chromatography, steam iron process, transport parameters
Karel Soukup; Jan Rogut; Jacek Grabowski; Marian Wiatowski; Magdalena Ludwik-Parda?a; Petr Schneider; Olga Ŗolcovß
Selective methane oxidation over promoted oxide catalysts. Quarterly report, March 1 - May 31, 1996
Series of catalysts consisting of MoO{sub 3}, V{sub 2}O{sub 5}, TiO{sub 2}, and SnO{sub 2} impregnated onto oxide supports consisting of SiO{sub 2} (Cab-O-Sil), TiO{sub 2} or SnO{sub 2} were previously prepared and tested for the selective oxidation of methane to oxygenates, and it was found that the V{sub 2}O{sub 5}/SiO{sub 2} catalyst was the most active and most selective toward the formation of formaldehyde. These catalysts have been characterized by laser Raman spectroscopy after dehydration and during the methane oxidation reaction with a CH{sub 4}/02 = 10/1 reaction mixture at 500{degrees}C in a continuous flow in situ reaction cell. With the V{sub 2}O{sub 5}/SiO{sub 2} catalyst (the most active catalyst among those studied), no significant structural changes were revealed by in situ Raman analyses, indicating that the fully oxidized surface sites were related to the high formaldehyde selectivivity. Over the V{sub 2}O{sub 5}/TiO{sub 2} and V{sub 2}O{sub 5}/SnO{sub 2} catalysts, CO and CO{sub 2} were the principal products produced by oxidation of methane. For the first time, in situ Raman analysis clearly showed that for these latter catalysts, the surface vanadium(V) oxide species were partially reduced under the steady-state reaction conditions. The performance of the V{sub 2}O{sub 5}/TiO{sub 2}/SiO{sub 2} catalyst was similar to that of the V{sub 2}O{sub 5}TiO{sub 2} catalyst, consistent with the earlier observation that vanadia was largely bound to the titania overlayer. It appears that formaldehyde selectivity decreased with increasing catalyst reducibility, but no direct correlation of catalyst activity with reductibility was observed.
Klier, K.; Herman, R.G.; Wang, C.-B.
Phototrophic Fe(II) Oxidation Promotes Organic Carbon Acquisition
Anoxygenic phototrophic Fe(II) oxidation is usually considered to be a lithoautotrophic metabolism that contributes to primary production in Fe-based ecosystems. In this study, we employed Rhodobacter capsulatus SB1003 as a model organism to test the hypothesis that phototrophic Fe(II) oxidation can be coupled to organic carbon acquisition. R. capsulatus SB1003 oxidized Fe(II) under anoxic conditions in a light-dependent manner, but it failed to grow lithoautotrophically on soluble Fe(II). When the strain was provided with Fe(II)-citrate, however, growth was observed that was dependent upon microbially catalyzed Fe(II) oxidation, resulting in the formation of Fe(III)-citrate. Subsequent photochemical breakdown of Fe(III)-citrate yielded acetoacetic acid that supported growth in the light but not the dark. The deletion of genes (RRC00247 and RRC00248) that encode homologs of atoA and atoD, required for acetoacetic acid utilization, severely impaired the ability of R. capsulatus SB1003 to grow on Fe(II)-citrate. The growth yield achieved by R. capsulatus SB1003 in the presence of citrate cannot be explained by lithoautotrophic growth on Fe(II) enabled by indirect effects of the ligand [such as altering the thermodynamics of Fe(II) oxidation or preventing cell encrustation]. Together, these results demonstrate that R. capsulatus SB1003 grows photoheterotrophically on Fe(II)-citrate. Nitrilotriacetic acid also supported light-dependent growth on Fe(II), suggesting that Fe(II) oxidation may be a general mechanism whereby some Fe(II)-oxidizing bacteria mine otherwise inaccessible organic carbon sources.
Rhodobacter Capsulatus Sb; Nicky C. Caiazza; Douglas P. Lies; Dianne K. Newman
Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. The testing was performed at Southern Research's Catalyst Test Facility, a bench-scale reactor capable of simulating gas-phase reactions occurring in coal-fired utility pollution-control equipment. Three different SCR catalysts are currently being studied in this project - honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Methods and procedures for experimental testing continue to be developed to produce the highest quality mercury-oxidation data. Most experiments so far have focused on testing the catalysts in a simulated Powder River Basin (PRB) flue-gas environment, which contains lower sulfur and chlorine than produced by other coals. Future work to characterize flue gas simulations typically derived from low and high sulfur bituminous coal will be performed in a stepwise manner, to avoid the constant interruptions in testing that occur when leaks in the system are generated during temperature transitions. Specifically, chlorine concentration vs. mercury oxidation graph will be developed for each catalyst. The contributions of temperature and later sulfur will be investigated after this is complete. Also, last quarter's tests showed a potential linear relationship between SO3 conversion and mercury oxidation. As a result, SO3 samples will be taken more frequently to investigate each catalyst's ability to selectively oxidize mercury.
Alex J. Berry; Thomas K. Gale
High quality oxide films on substrates
A method for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material.
Ruckman, Mark W. (Middle Island, NY); Strongin, Myron (Center Moriches, NY); Gao, Yong L. (Henrietta, NY)
Doped Titanium Oxide Nanotube Arrays with Enhanced ...
... Active Titania-Based Nanoparticles for Composite Propellant Combustion ... of Novel Nanostructured Electrolytes for Low Temperature Solid Oxide Fuel CellsĀ...
A method is described for providing an oxide film of a material on the surface of a substrate using a reactive deposition of the material onto the substrate surface in the presence of a solid or liquid layer of an oxidizing gas. The oxidizing gas is provided on the substrate surface in an amount sufficient to dissipate the latent heat of condensation occurring during deposition as well as creating a favorable oxidizing environment for the material. 4 figures.
Ruckman, M.W.; Strongin, M.; Gao, Y.L.
Oxidation Kinetics Modeling Applying Phase Field Approach
Presentation Title, Oxidation Kinetics Modeling Applying Phase Field Approach ... chemical reaction rates will increase exponentially and environmental attackĀ...
Evaluation of Commercially Available Oxidation Resistance ...
... Oxidation resistance alloy interconnects have been used in planar SOFC systems ... alloys under the SOFC interconnect dual exposure conditions: ...
Oxide Skin Strength Measurements on Molten Aluminum
Presentation Title, OXIDE SKIN STRENGTH MEASUREMENTS ON MOLTEN ALUMINUM ¢ MANGANESE ALLOYS WITH AND WITHOUT SALT ON SURFACE
Nanostructured Water Oxidation Catalysts - Energy Innovation ...
Nanostructured Cobalt Oxide Clusters in Mesoporous Silica as Efficient Oxygen-Evolving Catalysts. Angewandte Chemie International Edition. Vol. 28: ...
Oxidized Derivatives of Hydroxymethyl Furfural (HMF ...
Search PNNL. PNNL Home; About; Research; Publications; Jobs; News; Contacts; Oxidized Derivatives of Hydroxymethyl Furfural (HMF) Battelle Number(s): ...
Vapor phase modifiers for oxidative coupling
Volatilized metal compounds retard vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.
Warren, Barbara K. (Charleston, WV)
Oxide/Graphene Nanocomposite Functional Materials
Rare Earth Activated Oxides for Solid State Lighting Ę Rare Earth Doped Tellurite and Chalcogenide Planar Waveguide Amplifiers and Lasers Ę ReplacingĀ...
Dense high temperature ceramic oxide superconductors
Dense superconducting ceramic oxide articles of manufacture and methods for producing these articles are described. Generally these articles are produced by first processing these superconducting oxides by ceramic processing techniques to optimize materials properties, followed by reestablishing the superconducting state in a desired portion of the ceramic oxide composite.
Landingham, R.L.
Landingham, Richard L. (Livermore, CA)
Measurement system for metal-oxide gas sensors
A study on smell sensing and classification has been developed for a long time by many ways. Most of these have been focused on bad smells, when factors of bad smells were known chemically. Many gas sensors have been developed to detect specific chemicals. ... Keywords: Metal-oxide gas sensor, Multi-channel sensors, Smell measurement
Hideo Araki; Sigeru Omatu
Characterization of Oxide Layers Formed During Corrosion in Supercritical Water
.edu ABSTRACT The Supercritical Water Reactor is one of the Generation IV nuclear power plant designs envisioned of the Generation IV nuclear power plant designs envisioned for its high thermal efficiency and plant simplification for the study of oxide growth in steels and in zirconium alloys during exposure to supercritical water. A very
Motta, Arthur T.
Electrical conductivity of. gamma. -irradiated and chemically oxidized wool
Examples of wool fibers were irradiated with gamma rays and chemically oxidized with H/sub 2/O/sub 2/ to study the effect on their electrical conductivity. In both cases, electrical conductivity increased whereas the activation cnergy decreased with increases in diameter, moisture content and intrensic ash content of the wool samples.
Moharram, M.A. (Tanta Univ., Cairo, Egypt); Abou Sekkina, M.M.; Rabie, S.M.
p-type conduction in sputtered indium oxide films
We report p-type conductivity in intrinsic indium oxide (IO) films deposited by magnetron sputtering on fused quartz substrates under oxygen-rich ambient. Highly oriented (111) films were studied by x-ray diffraction, optical absorption, and Hall effect measurements. We fabricated p-n homojunctions on these films.
Stankiewicz, Jolanta; Alcala, Rafael [Instituto de Ciencia de Materiales de Aragon and Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, 50009 Zaragoza (Spain); Villuendas, Francisco [Departamento de Fisica Aplicada, Universidad de Zaragoza, 50009 Zaragoza (Spain)
Oxidation Resistance of Low Carbon Stainless Steel for Applications in Solid Oxide Fuel Cells
Alloys protected from corrosion by Cr2O3 (chromia) are recognized as potential replacements for LaCrO3¢based ceramic materials currently used as bipolar separators (interconnects) in solid oxide fuel cells (SOFC). Stainless steels gain their corrosion resistance from the formation of chromia, when exposed to oxygen at elevated temperatures. Materials for interconnect applications must form uniform conductive oxide scales at 600¢800o C while simultaneously exposed to air on the cathode side and mixtures of H2 - H2O, and, possibly, CHx and CO - CO2 on the anode side. In addition, they must possess good physical, mechanical, and thermal properties. Type 316L stainless steel was selected for the baseline study and development of an understanding of corrosion processes in complex gas environments. This paper discusses the oxidation resistance of 316L stainless steel exposed to dual SOFC environment for ~100 hours at ~900oK. The dual environment consisted of dry air on the cathode side of the specimen and a mixture of H2 and 3% H2O on the anode side. Post - corrosion surface evaluation involved the use of optical and scanning electron microscopy and x-ray diffraction analyses.
Ziomek-Moroz, Margaret; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Cramer, Stephen D.; Bullard, Sophie J.; Matthes, Steven A.; Dunning, John S.; Alman, David E.; Singh, P. (PNNL)
Pilot-Scale Evaluation of Mercury Oxidation Across SCR Catalysts
This study evaluated the effects of addition of various acid gas species on the oxidation of elemental mercury across two commercial SCR catalysts in a pilot SCR reactor operating on a slipstream from a Powder River Basin coal-fired power plant. Tests were conducted by the Western Kentucky University (WKU) to evaluate the impact of flue gas constituents (HCl, HF, HBr, HI, SO3, NH3:NO), operating conditions, and catalyst design on mercury oxidation. The results and data were reviewed by Reaction Engineer...
Assessment of the global impact of aerosols on tropospheric oxidants
[1] We present here a fully coupled global aerosol and chemistry model for the troposphere. The model is used to assess the interactions between aerosols and chemical oxidants in the troposphere, including (1) the conversion from gas-phase oxidants into the condensed phase during the formation of aerosols, (2) the heterogeneous reactions occurring on the surface of aerosols, and (3) the effect of aerosols on ultraviolet radiation and photolysis rates. The present study uses the global three-dimensional chemical/ transport model, Model for Ozone and Related Chemical Tracers, version 2 (MOZART-2), in which aerosols are coupled with the model. The model accounts for the presence of
Xuexi Tie; Sasha Madronich; Stacy Walters; David P. Edwards; Paul Ginoux; Natalie Mahowald; Renyi Zhang; Chao Lou; Guy Brasseur
To ensure safe storage, plutonium-bearing oxides are stabilized at 950 C for at least two hours in an oxidizing atmosphere. Stabilization conditions are expected to decompose organic impurities, convert metals to oxides, and result in moisture content below 0.5 wt%. During stabilization, the specific surface area is reduced, which minimizes readsorption of water onto the oxide surface. Plutonium oxides stabilized according to these criteria were sampled and analyzed to determine moisture content and surface area. In addition, samples were leached in water to identify water-soluble chloride impurity content. Results of these analyses for seven samples showed that the stabilization process produced low moisture materials (< 0.2 wt %) with low surface area ({le} 1 m{sup 2}/g). For relatively pure materials, the amount of water per unit surface area corresponded to 1.5 to 3.5 molecular layers of water. For materials with chloride content > 360 ppm, the calculated amount of water per unit surface area increased with chloride content, indicating hydration of hygroscopic salts present in the impure PuO{sub 2}-containing materials. The low moisture, low surface area materials in this study did not generate detectable hydrogen during storage of four or more years.
Crowder, M.; Duffey, J.; Livingston, R.; Scogin, J.; Kessinger, G.; Almond, P.
Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. Three different SCR catalysts are being studied. These are honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts are manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Test methods and experimental procedures were developed for current and future testing. The methods and procedures equalize factors influencing mercury adsorption and oxidation (surface area, catalyst activity, and pore structure) that normally differ for each catalyst type. Initial testing was performed to determine the time necessary for each catalyst to reach surface-adsorption equilibrium. In addition, the fraction of Hg oxidized by each of the SCR catalyst types is being investigated, for a given amount of catalyst and flow rate of mercury and flue gas. The next major effort will be to examine the kinetics of mercury oxidation across the SCR catalysts with respect to changes in mercury concentration and with respect to HCl concentration. Hg-sorption equilibrium times will also be investigated with respect to ammonia concentration in the simulated flue gas.
Jared W. Cannon; Thomas K. Gale
Scanning Transmission Electron Microscopy Investigations of Complex Oxides
Scanning Transmission Electron Microscopy Investigations of Complex Oxides Scanning Transmission Electron Microscopy Investigations of Complex Oxides Monday, May 23, 2011 - 3:30pm SSRL Conference room 137-322 Professor Tom Vogt, NanoCenter & Department of Chemistry, University of South Carolina High-Angle-Annular-Dark-Field/Scanning Transmission Electron Microscopy (HAADF/STEM) is a technique uniquely suited for detailed studies of the structure and composition of complex oxides. The HAADF detector collects electrons which have interact inelastically with the potentials of the atoms in the specimen and therefore resembles the better known Z2 (Z is atomic number) Rutherford scattering. One class of important catalysts consists of bronzes based on pentagonal {Mo6O21} building units; these include Mo5O14 and Mo17O47. In the last 20 years, new materials doped with
A method is presented for fabricating uranium oxide into a shaped refractory article by introducing a uranium halide fluxing reagent into the uranium oxide, and then mixing and compressing the materials into a shaped composite mass. The shaped mass of uranium oxide and uranium halide is then fired at an elevated temperature so as to form a refractory sintered article. It was found in the present invention that the introduction of a uraninm halide fluxing agent afforded a fluxing action with the uranium oxide particles and that excellent cohesion between these oxide particles was obtained. Approximately 90% of uranium dioxide and 10% of uranium tetrafluoride represent a preferred composition.
Hamilton, N.E.
Nitrogen Oxides Emission Control Options
Nitrogen Nitrogen Oxides Emission Control Options for Coal-Fired Electric Utility Boilers Ravi K. Srivastava and Robert E. Hall U.S. Environmental Protection Agency, National Risk Management Research Laboratory, Air Pollution Prevention and Control Division, Research Triangle Park, NC Sikander Khan and Kevin Culligan U.S. Environmental Protection Agency, Office of Air and Radiation, Clean Air Markets Division, Washington, DC Bruce W. Lani U.S. Department of Energy, National Energy Technology Laboratory, Environmental Projects Division, Pittsburgh, PA ABSTRACT Recent regulations have required reductions in emissions of nitrogen oxides (NO x ) from electric utility boilers. To comply with these regulatory requirements, it is increas- ingly important to implement state-of-the-art NO x con- trol technologies on coal-fired utility boilers. This paper reviews NO x control
Semiconductive Properties of Uranium Oxides
SEMICONDUCTIVE PROPERTIES OF URANIUM OXIDES SEMICONDUCTIVE PROPERTIES OF URANIUM OXIDES Thomas Meek Materials Science Engineering Department University of Tennessee Knoxville, TN 37931 Michael Hu and M. Jonathan Haire Chemical Technology Division Oak Ridge National Laboratory * Oak Ridge, Tennessee 37831-6179 August 2000 For the Waste Management 2001 Symposium Tucson, Arizona February 25-March 1, 2001 The submitted manuscript has been authored by a contractor of the U.S. Government under contract DE-AC05-00OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. _________________________ * Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy
The objective of this project is to understand the importance of and the contribution of gas-phase and solid-phase coal constituents in the mercury oxidation reactions. The project involves both experimental and modeling efforts. The team is comprised of the University of Utah, Reaction Engineering International, and the University of Connecticut. The objective is to determine the experimental parameters of importance in the homogeneous and heterogeneous oxidation reactions; validate models; and, improve existing models. Parameters to be studied include HCl, NO{sub x}, and SO{sub 2} concentrations, ash constituents, and temperature. This report summarizes Year 2 results for the experimental and modeling tasks. Experiments in the mercury reactor are underway and interesting results suggested that a more comprehensive look at catalyzed surface reactions was needed. Therefore, much of the work has focused on the heterogeneous reactions. In addition, various chemical kinetic models have been explored in an attempt to explain some discrepancies between this modeling effort and others.
JoAnn S. Lighty; Geoffrey Silcox; Andrew Fry; Constance Senior; Joseph Helble; Balaji Krishnakumar
Catalytic oxidative pyrolysis of liquid fuels
The oxidative pyrolysis of n-heptane was investigated with metal oxides Cr/sub 2/O/sub 3/, MnO/sub 2/, Fe/sub 2/O/sub 3/, NiO, Co/sub 3/O/sub 4/, and CuO supported on alumina. Metallic content of the catalyst weight varied from 0.1 to 2.0% with catalytic activity reaching a maximum when the metal content was 1%. The most active catalysts were Co/sub 3/O/sub 4/, MnO/sub 2/, and NiO. Pyrolysis of cyclohexane and toluene was also studied with Co/sub 3/O/sub 4/-Al/sub 2/O/sub 3/ as catalyst. Hydrocarbon stability and coke formation increase with increase of hydrocarbon condensation in the series paraffin < naphthalene < aromatic hydrocarbons. Pyrolysis of the various hydrocarbons at 800/sup 0/C yielded a gas that has an octane number of 90 to 93, and the process was shown to be adaptable to pyrolysis of various commercial fractions such as benzines A-72 and A-76, petroleum fractions, and liquid paraffins to produce gas of about the same octane. (BLM)
Antonova, V.M.; Gorlov, E.G.; Paushkin, Ya.M.
In situ vibrational spectroscopic investigation of C{sub 4} hydrocarbon selective oxidation over vanadium-phosphorus-oxide catalysts
n-Butane selective oxidation over the VPO catalyst to maleic anhydride is the first and only commercialized process of light alkane selective oxidation. The mechanism of this reaction is still not well known despite over twenty years of extensive studies, which can partially be attributed to the extreme difficulties to characterize catalytic reactions real-time under typical reaction conditions. In situ spectroscopic characterization techniques such as Infrared spectroscopy and laser Raman spectroscopy were used in the current mechanistic investigations of n-butane oxidation over VPO catalysts. To identify the reaction intermediates, oxidation of n-butane, 1,3-butadiene and related oxygenates on the VPO catalyst were monitored using FTIR spectroscopy under transient conditions. n-Butane was found to adsorb on the VPO catalyst to form olefinic species, which were further oxidized to unsaturated, noncyclic carbonyl species. The open chain dicarbonyl species then experienced cycloaddition to form maleic anhydride. VPO catalyst phase transformations were investigated using in situ laser Raman spectroscopy. This report contains Chapter 1: General introduction; Chapter 2: Literature review; and Chapter 5: Conclusion and recommendations.
Xue, Z.Y.
Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, [June--August 1993
The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The results will provide fundamental insight into oxidation, in term of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the twelfth quarter, wet and dry oxidation tests were done at room temperature on coal samples from the Pennsylvania State Coal Bank. Previous results had indicated that oxidation at high temperatures induced changes in surface properties through loss of volatiles. As-received and oxidized coal samples were studied by ion exchange methods to determine the carboxylate and phenolic group concentrations. Film flotation tests were done to characterize the floatability of as-received and oxidized coals. Surface area measurements were done on as-received coals.
Nanowire-based All Oxide Solar Cells
We present an all-oxide solar cell fabricated from vertically oriented zinc oxide nanowires and cuprous oxide nanoparticles. Our solar cell consists of vertically oriented n-type zinc oxide nanowires, surrounded by a film constructed from p-type cuprous oxide nanoparticles. Our solution-based synthesis of inexpensive and environmentally benign oxide materials in a solar cell would allow for the facile production of large-scale photovoltaic devices. We found that the solar cell performance is enhanced with the addition of an intermediate oxide insulating layer between the nanowires and the nanoparticles. This observation of the important dependence of the shunt resistance on the photovoltaic performance is widely applicable to any nanowire solar cell constructed with the nanowire array in direct contact with one electrode.
Yang*, Benjamin D. Yuhas and Peidong; Yang, Peidong
Mercury oxidization in dielectric barrier discharge plasma system
The pronounced volatility of elemental mercury (Hg{sup 0}) and some of its compounds, coupled with their extreme toxicity, makes these substances extremely hazardous. Conversion of Hg{sup 0} to HgO would significantly enhance mercury removal from flue gases. This investigation is focused on studying the effect of some of the constituents such as O{sub 2}, H{sub 2}O, CO{sub 2}, and NOx present in flue gases on elemental mercury oxidation in a dielectric barrier discharge (DBD) reactor. The results show that Hg vapors (6 ppbv) in a stream of 0.1% O{sub 2} and N{sub 2} are effectively oxidized at the energy density of up to 114 J/L. Hg conversion of over 80% is achieved when present in a gas mixture of 8% O{sub 2}, 2% H{sub 2}O, and 10% CO{sub 2} in N{sub 2} balance. The presence of NOx enhanced mercury oxidation in the DBD reactor. The oxidation chemistry is discussed. Studies show that Hg can be simultaneously removed along with the other two major pollutants, NOx and SO{sub 2}, in one DBD reactor followed by a wet scrubber system. This avoids the need of three techniques for the removal of major gaseous pollutants from coal-fired power plants.
Chen, Z.Y.; Mannava, D.P.; Mathur, V.K. [University New Hampshire, Durham, NH (United States). Dept. for Chemical Engineering
Ni(Al, Fe){sub 2}O{sub 4} ceramic alloys were reduced by hydrogen gas at a pressure of 1 atm, and at temperatures between 450 and 800 C. The reaction rate was determined from the rate of advance of the porous metal product layer-unreduced oxide interface. A simple analysis was presented permitting assessment of both the interface reaction resistance and the gas transport resistant through the porous product scales. The reaction was under mixed control in all conditions studied. In a range of temperatures and reaction times, preferred grain-boundary attack was observed. The conditions under which this was observed depended strongly on the Al{sup 3+} content of the ceramic alloy. Al{sup 3+} also lowered the interface reaction rate and inhibited scale coarsening by formation of dispersed unreduced phases in the product scales.
Allender, Jeffrey S.; DeJonghe, Lutgard C.
On the Acid-Base Mechanism for Ruthenium Water Oxidation Catalysts
We present a detailed theoretical study of the pathway for water oxidation in synthetic ruthenium-based catalysts. As a first step, we consider a recently discovered single center catalyst, where experimental observations ...
Wang, Lee-Ping
Hydrogen Oxidation and Evolution Reaction Kinetics on Platinum: Acid vs Alkaline Electrolytes
The kinetics of the hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) on polycrystalline platinum [Pt(pc)] and high surface area carbon-supported platinum nanoparticles (Pt/C) were studied in 0.1 M ...
Sheng, Wenchao
MANGANESE OXIDE AS A NEW CATHODE CATALYST IN MICROBIAL FUEL CELLS (MFCs).
??This study focused on manganese oxides with a cryptomelane-type octahedral molecular sieve (OMS-2) structure to replace platinum as a cathode catalyst in microbial fuel cellsģ (more)
Li, Xiang
Pt¢metal oxide aerogel catalysts: X-ray photoemission investigation
X-ray photoemission spectroscopy was used to study Pt¢metal oxide aerogel catalysts that have been developed to respond to increased NO x emissions of lean-burn engines. Lean-burn engines
A. J. Nelson; John G. Reynolds; R. D. Sanner; P. R. Coronado; L. M. Hair
Synthesis of Nano-Structured Metal-Oxides and Deposition via Ink ...
The objective of this study was to synthesize numerous metal oxide nano- structures including TiO2, Nb-doped TiO2, and SnO2 and deposit these materials onĀ...
Feasibility of breeding in hard spectrum boiling water reactors with oxide and nitride fuels
This study assesses the neutronic, thermal-hydraulic, and fuel performance aspects of using nitride fuel in place of oxides in Pu-based high conversion light water reactor designs. Using the higher density nitride fuel ...
Feng, Bo, Ph. D. Massachusetts Institute of Technology
Fusion Techniques for the Oxidation of Refractory Actinide Oxides
Small-scale experiments were performed to demonstrate the feasibility of fusing refractory actinide oxides with a series of materials commonly used to decompose minerals, glasses, and other refractories as a pretreatment to dissolution and subsequent recovery operations. In these experiments, 1-2 g of plutonium or neptunium oxide (PuO2 or NpO2) were calcined at 900 degrees Celsius, mixed and heated with the fusing reagent(s), and dissolved. For refractory PuO2, the most effective material tested was a lithium carbonate (Li2CO3)/sodium tetraborate (Na2B4O7) mixture which aided in the recovery of 90 percent of the plutonium. The fused product was identified as a lithium plutonate (Li3PuO4) by x-ray diffraction. The use of a Li2CO3/Na2B4O7 mixture to solubilize high-fired NpO2 was not as effective as demonstrated for refractory PuO2. In a small-scale experiment, 25 percent of the NpO2 was oxidized to a neptunium (VI) species that dissolved in nitric acid. The remaining neptunium was then easily recovered from the residue by fusing with sodium peroxide (Na2O2). Approximately 70 percent of the neptunium dissolved in water to yield a basic solution of neptunium (VII). The remainder was recovered as a neptunium (VI) solution by dissolving the residue in 8M nitric acid. In subsequent experiments with Na2O2, the ratio of neptunium (VII) to (VI) was shown to be a function of the fusion temperature, with higher temperatures (greater than approximately 400 degrees C) favoring the formation of neptunium (VII). The fusion of an actual plutonium-containing residue with Na2O2 and subsequent dissolution was performed to demonstrate the feasibility of a pretreatment process on a larger scale. Sodium peroxide was chosen due to the potential of achieving higher actinide recoveries from refractory materials. In this experiment, nominally 10 g of a graphite-containing residue generated during plutonium casting operations was initially calcined to remove the graphite. Removal of combustible material prior to a large-scale fusion with Na2O2 is needed due to the large amount of heat liberated during oxidation. Two successive fusions using the residue from the calcination and the residue generated from the initial dissolution allowed recovery of 98 percent of the plutonium. The fusion of the residue following the first dissolution was performed at a higher temperature (600 degrees Celsius versus 450 degrees Celsius during the first fusion). The ability to recover most of the remaining plutonium from the residue suggest the oxidation efficiency of the Na2O2 fusion improves with higher temperatures similar to results observed with NpO2 fusion.
Rudisill, T.S.
Reduction of Oxidative Melt Loss of Aluminum and Its Alloys
This project led to an improved understanding of the mechanisms of dross formation. The microstructural evolution in industrial dross samples was determined. Results suggested that dross that forms in layers with structure and composition determined by the local magnesium concentration alone. This finding is supported by fundamental studies of molten metal surfaces. X-ray photoelectron spectroscopy data revealed that only magnesium segregates to the molten aluminum alloy surface and reacts to form a growing oxide layer. X-ray diffraction techniques that were using to investigate an oxidizing molten aluminum alloy surface confirmed for the first time that magnesium oxide is the initial crystalline phase that forms during metal oxidation. The analytical techniques developed in this project are now available to investigate other molten metal surfaces. Based on the improved understanding of dross initiation, formation and growth, technology was developed to minimize melt loss. The concept is based on covering the molten metal surface with a reusable physical barrier. Tests in a laboratory-scale reverberatory furnace confirmed the results of bench-scale tests. The main highlights of the work done include: A clear understanding of the kinetics of dross formation and the effect of different alloying elements on dross formation was obtained. It was determined that the dross evolves in similar ways regardless of the aluminum alloy being melted and the results showed that amorphous aluminum nitride forms first, followed by amorphous magnesium oxide and crystalline magnesium oxide in all alloys that contain magnesium. Evaluation of the molten aluminum alloy surface during melting and holding indicated that magnesium oxide is the first crystalline phase to form during oxidation of a clean aluminum alloy surface. Based on dross evaluation and melt tests it became clear that the major contributing factor to aluminum alloy dross was in the alloys with Mg content. Mg was identified as the primary factor that accelerates dross formation specifically in the transition from two phases to three phase growth. Limiting magnesium oxidation on the surface of molten aluminum therefore becomes the key to minimizing melt loss, and technology was developed to prevent magnesium oxidation on the aluminum surface. This resulted in a lot of the work being focused on the control of Mg oxidation. Two potential molten metal covering agents that could inhibit dross formation during melting and holding consisting of boric acid and boron nitride were identified. The latter was discounted by industry as it resulted in Boron pick up by the melt beyond that allowed by specifications during plant trials. The understanding of the kinetics of dross formation by the industry partners helped them understand how temperature, alloy chemistry and furnace atmosphere (burner controls--e.g. excess air) effected dross formation. This enables them to introduce in their plant process changes that reduced unnecessary holding at high temperatures, control burner configurations, reduce door openings to avoid ingress of air and optimize charge mixes to ensure rapid melting and avoid excess oxidation.
Dr. Subodh K. Das; Shridas Ningileri
This report describes the development of a dissolution flowsheet for neptunium (Np) oxide (NpO{sub 2}) residues (i.e., various NpO{sub 2} sources, HB-Line glovebox sweepings, and Savannah River National Laboratory (SRNL) thermogravimetric analysis samples). Samples of each type of materials proposed for processing were dissolved in a closed laboratory apparatus and the rate and total quantity of off-gas were measured. Samples of the off-gas were also analyzed. The quantity and type of solids remaining (when visible) were determined after post-dissolution filtration of the solution. Recommended conditions for dissolution of the NpO{sub 2} residues are: Solution Matrix and Loading: {approx}50 g Np/L (750 g Np in 15 L of dissolver solution), using 8 M nitric acid (HNO{sub 3}), 0.025 M potassium fluoride (KF) at greater than 100 C for at least 3 hours. Off-gas: Analysis of the off-gas indicated nitric oxide (NO), nitrogen dioxide (NO{sub 2}) and nitrous oxide (N{sub 2}O) as the only identified components. No hydrogen (H{sub 2}) was detected. The molar ratio of off-gas produced per mole of Np dissolved ranged from 0.25 to 0.4 moles of gas per mole of Np dissolved. A peak off-gas rate of {approx}0.1 scfm/kg bulk oxide was observed. Residual Solids: Pure NpO{sub 2} dissolved with little or no residue with the proposed flowsheet but the NpCo and both sweepings samples left visible solid residue after dissolution. For the NpCo and Part II Sweepings samples the residue amounted to {approx}1% of the initial material, but for the Part I Sweepings sample, the residue amounted to {approx}8 % of the initial material. These residues contained primarily aluminum (Al) and silicon (Si) compounds that did not completely dissolve under the flowsheet conditions. The residues from both sweepings samples contained minor amounts of plutonium (Pu) particles. Overall, the undissolved Np and Pu particles in the residues were a very small fraction of the total solids.
Kyser, E
Why Sequence Freshwater Iron-Oxidizing Bacteria?
Freshwater Iron-Oxidizing Bacteria? Freshwater Iron-Oxidizing Bacteria? The goal of this project is to obtain complete genome sequences for six different freshwater iron (Fe)-oxidizing bacteria (FeOB). Four of these are oxygen-dependent iron-oxidizing ╬▓-proteobacteria, and three of these, Sideroxydans lithotrophicus, Gallionella capsiferriformans, and strain TW-2, are capable of chemolithoautotrophic growth (that is, obtaining energy by the oxidation of inorganic compounds) using Fe(II) as sole energy source under microaerobic (low-oxygen) conditions. The fourth organism, Leptothrix cholodnii, is a sheath-forming heterotrophic (i.e., using complex organic compounds for nutrition) organism that oxidizes both Fe(II) and Mn(II) and deposits a ferromanganic coating on its sheath. In addition,
Noble Metal Catalysts for Mercury Oxidation in Utility Flue Gas: Gold, Palladium and Platinum Formulations
The use of noble metals as catalysts for mercury oxidation in flue gas remains an area of active study. To date, field studies have focused on gold and palladium catalysts installed at pilot scale. In this article, we introduce bench-scale experimental results for gold, palladium and platinum catalysts tested in realistic simulated flue gas. Our initial results reveal some intriguing characteristics of catalytic mercury oxidation and provide insight for future research into this potentially important process.
Presto, A.A.; Granite, E.J
Preliminary research has shown that SCR catalysts employed for nitrogen-oxide reduction can effectively oxidize mercury. This report discusses initial results from fundamental investigations into the behavior of mercury species in the presence of SCR catalysts at Southern Research Institute. The testing was performed at Southern Research's Catalyst Test Facility, a bench-scale reactor capable of simulating gas-phase reactions occurring in coal-fired utility pollution-control equipment. Three different SCR catalysts are currently being studied in this project--honeycomb-type, plate-type, and a hybrid-type catalyst. The catalysts were manufactured and supplied by Cormetech Inc., Hitachi America Ltd., and Haldor-Topsoe Inc., respectively. Parametric testing was performed to investigate the contribution of flue-gas chemistry on mercury oxidation via SCR catalysts. Methods and procedures for experimental testing continue to be developed to produce the highest quality mercury-oxidation data. During this past quarter, it was discovered that long periods (12 - 24 hours) are required to equilibrate the catalysts in the system. In addition, after the system has been equilibrated, operational changes to temperature, gas concentration, or flow rate shifts the equilibrium, and steady-state must be reestablished, which can require as much as twelve additional hours per condition change. In the last quarter of testing, it was shown that the inclusion of ammonia had a strong effect on the oxidation of mercury by SCR catalysts, both in the short-term (a transitional period of elemental and oxidized mercury off gassing) and the long-term (less steady-state mercury oxidation). All experiments so far have focused on testing the catalysts in a simulated Powder River Basin (PRB) flue-gas environment, which contains lower sulfur and chlorine than produced by other coals. In the next quarter, parametric testing will be expanded to include flue gases simulating power plants burning Midwestern and Eastern coals, which are higher in sulfur and chlorine. Also, the isolation of such gases as hydrogen chloride (HCl), ammonia (NH{sub 3}), and sulfur trioxide (SO{sub 3}) will be investigated. All of these efforts will be used to examine the kinetics of mercury oxidation across the SCR catalysts with respect to flue gas composition, temperature, and flow rate.
Oxidation of hydrogen halides to elemental halogens
A process for oxidizing hydrogen halides having substantially no sulfur impurities by means of a catalytically active molten salt is disclosed. A mixture of the subject hydrogen halide and an oxygen bearing gas is contacted with a molten salt containing an oxidizing catalyst and alkali metal normal sulfates and pyrosulfates to produce an effluent gas stream rich in the elemental halogen and substantially free of sulfur oxide gases.
Rohrmann, Charles A. (Kennewick, WA); Fullam, Harold T. (Richland, WA)
Metal oxide composite dosimeter method and material
The present invention is a method of measuring a radiation dose wherein a radiation responsive material consisting essentially of metal oxide is first exposed to ionizing radiation. The metal oxide is then stimulating with light thereby causing the radiation responsive material to photoluminesce. Photons emitted from the metal oxide as a result of photoluminescence may be counted to provide a measure of the ionizing radiation.
Miller, Steven D. (Richland, WA)
A process for making an aqueous magnesium oxide slip casting slurry comprising the steps of mixing finely ground fused magnesium oxide with water, milling the slurry for at least 30 hours at a temperature of 2-10 deg C (the low temperature during milling inhibiting the formation of hydrated magnesium oxide), discharging the slurry from the mill, adding hydrochloric acid as a deflocculent, and adding a scum inhibitor is presented. (AEC)
Stoddard, S.D.; Nuckolls, D.E.
Solid-oxide fuel cell electrolyte
This invention is comprised of a solid-oxide electrolyte operable at between 600{degrees}C and 800{degrees}C and a method of producing the solid-oxide electrolyte. The solid-oxide electrolyte comprises a combination of a compound having a weak metal-oxygen interactions with a compound having stronger metal-oxygen interactions whereby the resulting combination has both strong and weak metal-oxygen interaction properties.
Bloom, I.D.; Hash, M.C.; Krumpelt, M.
Preparation and Characterization of Uranium Oxides in Support of the K Basin Sludge Treatment Project
Uraninite (UO2) and metaschoepite (UO3Ę2H2O) are the uranium phases most frequently observed in K Basin sludge. Uraninite arises from the oxidation of uranium metal by anoxic water and metaschoepite arises from oxidation of uraninite by atmospheric or radiolytic oxygen. Studies of the oxidation of uraninite by oxygen to form metaschoepite were performed at 21░C and 50░C. A uranium oxide oxidation state characterization method based on spectrophotometry of the solution formed by dissolving aqueous slurries in phosphoric acid was developed to follow the extent of reaction. This method may be applied to determine uranium oxide oxidation state distribution in K Basin sludge. The uraninite produced by anoxic corrosion of uranium metal has exceedingly fine particle size (6 nm diameter), forms agglomerates, and has the formula UO2.004▒0.007; i.e., is practically stoichiometric UO2. The metaschoepite particles are flatter and wider when prepared at 21░C than the particles prepared at 50░C. These particles are much smaller than the metaschoepite observed in prolonged exposure of actual K Basin sludge to warm moist oxidizing conditions. The uraninite produced by anoxic uranium metal corrosion and the metaschoepite produced by reaction of uraninite aqueous slurries with oxygen may be used in engineering and process development testing. A rapid alternative method to determine uranium metal concentrations in sludge also was identified.
Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.
Nanostructured manganese oxide clusters supported on ...
2 evolution at nano-structured Mn oxide clusters in mesoporous silica under very mild conditions for the ?rst time. For driving the catalyst with
Metal Current Collector Protected by Oxide Film
For Industry; For Researchers; Success Stories; About Us; ... metal felt made substantially of inexpensive ferritic steel coated with a thin oxide film, ...
MULTIPLE OXIDANT CHROMIUM LEACHING FROM HANFORD WASTE USDOE Aluminum Chromium Leaching Workshop January 24th, 2007 Jennifer E. Holland, Ph.D. Chairman, President, CEO
Batteries with Orthorhombic Sodium Manganese Oxide Cathodes
Berkeley National Laboratory researchers have discovered a low-cost, low-toxicity manganese oxide for rechargeable lithium and sodium batteries.
Double perovskite catalysts for oxidative coupling
Alkali metal doped double perovskites containing manganese and at least one of cobalt, iron and nickel are useful in the oxidative coupling of alkane to higher hydrocarbons.
Volatilized metal compounds are described which are capable of retarding vapor phase alkane conversion reactions in oxidative coupling processes that convert lower alkanes to higher hydrocarbons.
Warren, B.K.
EIA - Greenhouse Gas Emissions - Nitrous Oxide Emissions
Annual Energy Outlook 2012 (EIA)
nitrous oxide emisssions from industrial sources, 1990, 2005, 2008, and 2009 4.5. Waste management sources In 2009, treatment of residential and commercial wastewater produced 92...
Microstructure Design of Solid Oxide Fuel Cell
The porous heterogeneous cathode microstructure of solid Oxide fuel cells ... Computer Simulations of Realistic Multi-Phase Three-Dimensional Microstructures.
Lanthanide doped barium phosphorous oxide scintillators
The present invention provides for a composition comprising an inorganic scintillator comprising a lanthanide-doped barium phosphorous oxide useful for detecting nuclear material.
Borade, Ramesh B; Bourret-Courchesne, Edith; Denzo, Stephen E
Cholesterol and Phytosterol Oxidation ProductsChapter 2 Extraction and Purification of Cholesterol Oxidation Products
Cholesterol and Phytosterol Oxidation Products Chapter 2 Extraction and Purification of Cholesterol Oxidation Products Food Science Health Nutrition Biochemistry eChapters Food Science & Technology Health - Nutrition - Biochemistry Pr
Analysis of Lipid OxidationChapter 5 Analysis of Lipid Oxidation Products by NMR Spectroscopy
Analysis of Lipid Oxidation Chapter 5 Analysis of Lipid Oxidation Products by NMR Spectroscopy Methods and Analyses eChapters Methods - Analyses Books AOCS Press Downloadable pdf of Chapter 5 Analysis of Lipid Oxi
Lipid Oxidation PathwaysChapter 9 Protein Alterations Due to Lipid Oxidation in Multiphase Systems
Lipid Oxidation Pathways Chapter 9 Protein Alterations Due to Lipid Oxidation in Multiphase Systems Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf of Chapter 9 P
Cholesterol and Phytosterol Oxidation ProductsChapter 3 Determination of Cholesterol Oxidation Products by Gas Chromatography
Cholesterol and Phytosterol Oxidation Products Chapter 3 Determination of Cholesterol Oxidation Products by Gas Chromatography Food Science Health Nutrition Biochemistry eChapters Food Science & Technology Health - Nutrition - Biochemi
Lipid Oxidation PathwaysChapter 4 Kinetic Evaluation of the Antioxidant Activity in Lipid Oxidation
Lipid Oxidation Pathways Chapter 4 Kinetic Evaluation of the Antioxidant Activity in Lipid Oxidation Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf of Chapter 4
Reduction of native oxides on InAs by atomic layer deposited Al{sub 2}O{sub 3} and HfO{sub 2}
Thin high-{kappa} oxide films on InAs, formed by atomic layer deposition, are the key to achieve high-speed metal-oxide-semiconductor devices. We have studied the native oxide and the interface between InAs and 2 nm thick Al{sub 2}O{sub 3} or HfO{sub 2} layers using synchrotron x-ray photoemission spectroscopy. Both films lead to a strong oxide reduction, obtaining less than 10% of the native As-oxides and between 10% and 50% of the native In-oxides, depending on the deposition temperature. The ratio of native In- to As-oxides is determined to be 2:1. The exact composition and the influence of different oxidation states and suboxides is discussed in detail.
Timm, R.; Fian, A.; Hjort, M.; Thelander, C.; Lind, E.; Andersen, J. N.; Wernersson, L.-E.; Mikkelsen, A. [Department of Physics, Nanometer Structure Consortium, Lund University, P.O. Box 118, 22 100 Lund (Sweden)
Partial oxidation reforming of methanol
Methanol is an attractive fuel for fuel cell-powered vehicles because it has a fairly high energy density, can be pumped into the tank of a vehicle mush like gasoline, and is relatively easy to reform. For on-board reforming, the reformer must be compact and lightweight, and have rapid start-up and good dynamic response. Steam reforming reactors with the tube-and-shell geometry that was used on the prototype fuel cell-powered buses are heat transfer limited. To reach their normal operating temperature, these types of reactors need 45 minutes from ambient temperature start-up. The dynamic response is poor due to temperature control problems. To overcome the limitations of steam reforming, ANL explored the partial oxidation concept used in the petroleum industry to process crude oils. In contrast to the endothermic steam reforming reaction, partial oxidations is exothermic. Fuel and air are passed together over a catalyst or reacted thermally, yielding a hydrogen-rich gas. Since the operating temperature of such a reactor can be controlled by the oxygen-to- methanol ratio, the rates of reaction are not heat transfer limited. Start-up and transient response should be rapid, and the mass and volume are expected to be small by comparison.
Krumpelt, M.; Ahmed, S.; Kumar, R.
Electrochemical oxidation of organic materials
This invention is a method and apparatus for the direct oxidation of organic materials, especially organic wastes, in an electrochemical cell. It fulfills the need for a simple, cost-effective way for generators of small quantities of waste to deal with that waste. It does not use an electron transfer agent, which may be a source of additional hazardous waste. The anode is made of carbon felt; the cathode is platinum; and the electrolyte is a strong oxidizer, preferably nitric acid. The potential difference is 2 to 3 volts; the current density is 0.15 to 0.25 A/cm{sup 2}. The porous barrier is a medium grade alumina frit or an ion exchange membrane. The organic materials are fed to the anode compartment; the resulting oxygen bubbling circumvents the need for stirring or circulating the waste. Many different types of waste (e.g. rubber gloves, TBP, process solutions, etc.) can be fed to the anode compartment without the need to process or store it. 3 figs. (DLC)
Almon, A.C.
Structure and Stability of Small Boron and Boron Oxide Clusters
In order to rationally design and explore a potential energy source based on the highly exothermic oxidation of boron, density functional theory (DFT) was used to characterize small boron clusters with 0-3 oxygen atoms and total of up to ten atoms. The structures, vibrational frequencies, and stabilities were calculated for each of these clusters. A quantum molecular dynamics procedure was used to locate the global minimum for each species, which proved to be crucial given the unintuitive structure of many of the most stable isomers. Additionally, due to the plane-wave, periodic DFT code used in this study, a straightforward comparison of these clusters to the bulk boron and B2O3 structures was possible, despite the great structural and energetic differences between the two forms. Through evaluation of previous computational and experimental work, the relevant low-energy structures of all but one of the pure boron clusters can be assigned with great certainty. Nearly all of the boron oxide clusters are described here for the first time, but there are strong indications that the DFT procedure chosen is particularly well-suited for the task. Insight into the trends in boron and boron oxide cluster stabilities, as well as the ultimate limits of growth for each, are also provided. The work reported herein provides crucial information towards understanding the oxidation of boron at a molecular level.
Sumpter, Bobby G [ORNL; Drummond, Michael L [ORNL; Meunier, Vincent [ORNL
Deactivation Mechanisms of Pt/Pd-based Diesel Oxidation Catalysts
Currently precious metal-based diesel oxidation catalysts (DOC) containing platinum (Pt) and palladium (Pd) are most commonly used for the oxidation of hydrocarbon and NO in diesel exhaust hydrocarbon oxidation. The present work has been carried out to investigate the deactivation mechanisms of the DOC from its real-world vehicle operation by coupling its catalytic activity measurements with surface characterization including x-ray diffraction, transmission electron microscopy, and x-ray photoelectron spectroscopy. A production Pt-Pd DOC was obtained after being aged on a vehicle driven for 135,000 miles in order to study its deactivation behavior. The performance of the vehicle-aged part was correlated with that of the simulated hydrothermal lab aged sample assuming that Pt-Pd sintering plays a major role in irreversible catalyst deactivation. In addition to the hydrothermal sintering, the deterioration of hydrocarbon and NO oxidation performance was caused by surface poisoning. The role of the various aging factors in determining long-term performance in mobile applications will be discussed.
Wiebenga, Michelle H.; Kim, Chang H.; Schmieg, Steven J.; Oh, Se H.; Brown, David B.; Kim, Do Heui; Lee, Jong H.; Peden, Charles HF
Formation of zinc oxide films using submicron zinc particle dispersions
The thermal oxidation of submicron metallic Zn particles was studied as a method to form nanostructured ZnO films. The particles used for this work were characterized by electron microscopy, x-ray diffraction and thermal analysis to evaluate the Zn-ZnO core shell structure, surface morphology, and oxidation characteristics. Significant nanostructural changes were observed for films annealed to 400 ░C or higher, where nanoflakes, nanoribbons, nanoneedles and nanorods were formed as a result of stress induced fractures arising in the ZnO outer shell due to differential thermal expansion between the metallic Zn core and the ZnO shell. Mass transport occurs through these defects due to the high vapor pressure for metallic Zn at temperatures above 230 ░C, whereupon the Zn vapor rapidly oxidizes in air to form the ZnO nanostructures. The Zn particles were also incorporated into zinc indium oxide precursor solutions to form thin film transistor test structures to evaluate the potential of forming nanostructured field effect sensors using simple solution processing.
Rajachidambaram, Meena Suhanya; Varga, Tamas; Kovarik, Libor; Sanghavi, Rahul P.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Han, Seungyeol; Chang, Chih-hung; Herman, Gregory S.
Implications of mercury interactions with band-gap semiconductor oxides
Titanium dioxide is a well-known photooxidation catalyst. It will oxidize mercury in the presence of ultraviolet light from the sun and oxygen and/or moisture to form mercuric oxide. Several companies manufacture self-cleaning windows. These windows have a transparent coating of titanium dioxide. The titanium dioxide is capable of destroying organic contaminants in air in the presence of ultraviolet light from the sun, thereby keeping the windows clean. The commercially available self-cleaning windows were used to sequester mercury from oxygen¢nitrogen mixtures. Samples of the self-cleaning glass were placed into specially designed photo-reactors in order to study the removal of elemental mercury from oxygen¢nitrogen mixtures resembling air. The possibility of removing mercury from ambient air with a self-cleaning glass apparatus is examined. The intensity of 365-nm ultraviolet light was similar to the natural intensity from sunlight in the Pittsburgh region. Passive removal of mercury from the air may represent an option in lieu of, or in addition to, point source clean-up at combustion facilities. There are several common band-gap semiconductor oxide photocatalysts. Sunlight (both the ultraviolet and visible light components) and band-gap semiconductor particles may have a small impact on the global cycle of mercury in the environment. The potential environmental consequences of mercury interactions with band-gap semiconductor oxides are discussed. Heterogeneous photooxidation might impact the global transport of elemental mercury emanating from flue gases.
Granite, E.J.; King, W.P.; Stanko, D.C.; Pennline, H.W.
Kinetics and dynamics of oxidation reactions involving an adsorbed CO species on bulk and supported platinum and copper-oxide. First year annual report, January 1, 1991--December 31, 1991
Application of the GRI 1.2 methane oxidation model to methane and methanol oxidation in supercritical water
The GRI 1.2 mechanism is used to predict the oxidation rates of methane and methanol by oxygen in supercritical water at 250 bar and temperatures ranging from 420--630 C. Using the Chemkin II computational package which assumes an ideal gas equation of state, the GRI model does very well in representing the available experimental results on methane over a wide temperature and concentration rate. However, the model may lack key CH{sub 3}O{sub 2} reactions needed for a complete description in the < 450 C region. The oxidation of methanol and formation of formaldehyde is not well represented by the GRI mechanism when left unchanged. If two important modifications are made to the reactivity of HO{sub 2}, good agreement with the methanol oxidation results is achieved. This paper illustrates that the carefully-assembled GRI 1.2 mechanism, although designed for conventional combustion conditions, can be successfully extended with very little modification to much lower temperature and extreme pressure conditions. The purpose of this study is to understand the operative chemical kinetics of supercritical water oxidation required for the more efficient application of this technology to treatment of hazardous wastes, obsolete munitions, rocket motors, and chemical warfare agents.
Rice, S.F. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility
Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. Technical progress report, [March--May 1992
during the seventh quarter, electrokinetic, humic acid extraction and film flotation tests were done on oxidized samples of Upper Freeport coal from the Troutville {number_sign} 2 Mine, Clearfield County, Pennsylvania. Scanning electron microscopy and energy dispersive X-ray analysis was done to characterize the morphology and composition of the surface of as-received coal, oxidized coal, oxidized coal after extraction of humic acids and humic acid extracted from oxidized coal. In addition, electrochemical studies were done on electrodes prepared from coal pyrite samples.
Increased Cytotoxicity of Oxidized Flame Soot
Increased Cytotoxicity of Oxidized Flame Soot Increased Cytotoxicity of Oxidized Flame Soot Title Increased Cytotoxicity of Oxidized Flame Soot Publication Type Journal Article Year of Publication 2012 Authors Holder, Amara L., Brietta J. Carter, Regine Goth-Goldstein, Donald Lucas, and Catherine P. Koshland Journal Atmospheric Pollution Research Volume 3 Start Page 25 Issue 1 Pagination 25-31 Date Published 01/2012 Keywords health effects, ozone, soot, toxicity Abstract Combustion-generated particles released into the atmosphere undergo reactions with oxidants, which can change the particles' physiochemical characteristics. In this work, we compare the physical and chemical properties and cellular response of particles fresh from a flame with those oxidized by ozone and nitrogen dioxide. The reaction with ozone and nitrogen dioxide does not significantly modify the physical characteristics of the particles (primary particle size, fractal dimension, and surface area). However, oxidation affects the chemical characteristics of the particles, creating more oxygen and nitrogen containing functional groups, and increases their hydrophilicity. In addition, oxidized soot generates more reactive oxygen species, as measured by the dithiothreitol (DTT) assay. Furthermore, oxidized soot is 1.5-2 times more toxic than soot that was not reacted with ozone, but the inflammatory response, measured by interleukin-8 (IL-8) secretion, is unchanged. These results imply that combustion-generated particles released into the atmosphere will have an increased toxicity on or after high ozone days.
Nanocomposite of graphene and metal oxide materials
Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.
Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo
Sulfur oxide adsorbents and emissions control
High capacity sulfur oxide absorbents utilizing manganese-based octahedral molecular sieve (Mn--OMS) materials are disclosed. An emissions reduction system for a combustion exhaust includes a scrubber 24 containing these high capacity sulfur oxide absorbents located upstream from a NOX filter 26 or particulate trap.
Li, Liyu (Richland, WA); King, David L. (Richland, WA)
Destruction of organic wastes with molten oxidizers
A process for destruction of biologically hazardous organic chemical wastes by using liquefied strongly oxidizing inorganic salts, such as the alkali metal nitrates, at high temperatures and atmospheric pressure, to yield inorganic salts, carbon dioxide, and water. The oxidizing salts are regenerated and recycled.
Bradshaw, R.W.; Holmes, J.T.; Tyner, C.E.
Ammonia release method for depositing metal oxides
A method of depositing metal oxides on substrates which is indifferent to the electrochemical properties of the substrates and which comprises forming ammine complexes containing metal ions and thereafter effecting removal of ammonia from the ammine complexes so as to permit slow precipitation and deposition of metal oxide on the substrates.
Silver, G.L.; Martin, F.S.
Oxidation of coal and coal pyrite mechanisms and influence on surface characteristics. [Quarterly] technical progress report, April--June 1993
The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The results will provide fundamental insight into oxidation, in terms of the bulk and surface chemistry, the microstructure, and the semiconductor properties of the pyrite. During the eleventh quarter, dry thermal oxidation tests were done on coal samples from the Pennsylvania State Coal Bank. As-received and oxidized coal samples were studied by ion-exchange methods to determine the carboxylate and phenolic group concentrations. Film flotation tests were done to characterize the flotability of as-received and oxidized coals. In addition, electrokinetic tests were done on different coals, to obtain information pertinent to the selection of flotation reagents. DRIFT analysis was done to characterize the structure of coals.
Compositional Study of Neutron Detecting Glasses
The current study involves the production and characterization of glass with high concentrations of Gd2O3 in various oxide glass formers, and containing one ofĀ...
nitrogen oxides | OpenEI
Open Energy Info (EERE)
20 20 Varnish cache server Browse Upload data GDR 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 2142279720 Varnish cache server nitrogen oxides Dataset Summary Description Emissions from energy use in buildings are usually estimated on an annual basis using annual average multipliers. Using annual numbers provides a reasonable estimation of emissions, but it provides no indication of the temporal nature of the emissions. Therefore, there is no way of understanding the impact on emissions from load shifting and peak shaving technologies such as thermal energy storage, on-site renewable energy, and demand control. Source NREL Date Released April 11th, 2011 (3 years ago) Date Updated April 11th, 2011 (3 years ago)
A method is presented for recovering heavy water from uranium oxide-- heavy water slurries. The method consists in saturating such slurries with a potassium nitrate-sodium nitrate salt mixture and then allowing the self-heat of the slurry to raise its temperature to a point slightly in excess of 100 deg C, thus effecting complete evaporation of the free heavy water from the slurry. The temperature of the slurry is then allowed to reach 300 to 900 deg C causing fusion of the salt mixture and expulsion of the water of hydration. The uranium may be recovered from the fused salt mixture by treatment with water to leach the soluble salts away from the uranium-containing residue.
Hiskey, C.F.
Factors Affecting the Oxidative Stability of Foods-Interesterified Soybean Oil with High Intensity Ultrasound Treatment and Trona Mineral in Packaged Fresh Meats.
??Oxidation in oils and muscle foods has been studied for many years to understand its mechanism and furthermore to control and manage it. A seriesģ (more)
Lee, Jiwon
Gasoline and Diesel Fuel Update (EIA)
4. Nitrous Oxide Emissions 4. Nitrous Oxide Emissions 4.1 Total emissions U.S. nitrous oxide emissions in 2009 were 4 MMTCO2e (1.7 percent) below their 2008 total (Table 22). Sources of U.S. nitrous oxide emissions include agriculture, energy use, industrial processes, and waste management (Figure 22). The largest source is agriculture (73 percent), and the majority of agricultural emissions result from nitrogen fertilization of agricultural soils (87 percent of the agriculture total) and management of animal waste (13 percent). U.S. nitrous oxide emissions rose from 1990 to 1994, fell from 1994 to 2002, and returned to an upward trajectory from 2003 to 2007, largely as a result of increased use of synthetic fertilizers. Fertilizers are the primary contributor of emissions from nitrogen fertilization of soils, which grew by more than 30 percent from
Graphite oxidation modeling for application in MELCOR.
The Arrhenius parameters for graphite oxidation in air are reviewed and compared. One-dimensional models of graphite oxidation coupled with mass transfer of oxidant are presented in dimensionless form for rectangular and spherical geometries. A single dimensionless group is shown to encapsulate the coupled phenomena, and is used to determine the effective reaction rate when mass transfer can impede the oxidation process. For integer reaction order kinetics, analytical expressions are presented for the effective reaction rate. For noninteger reaction orders, a numerical solution is developed and compared to data for oxidation of a graphite sphere in air. Very good agreement is obtained with the data without any adjustable parameters. An analytical model for surface burn-off is also presented, and results from the model are within an order of magnitude of the measurements of burn-off in air and in steam.
Gelbard, Fred
Packaging and Transportation of Additional Neptunium Oxide
The Savannah River Site's HB-Line Facility completed a second neptunium oxide production campaign in which nine (9) additional cans of neptunium oxide were produced and shipped to the Idaho National Laboratory and Oak Ridge National Laboratory in the 9975 shipping container. These additional cans were from a different feed solution than the first fifty (50) cans of neptunium oxide that were previously produced and shipped via a Letter of Amendment to the 9975 Safety Analysis Report for Packaging (SARP) content table. This paper will address the challenges associated with demonstrating the neptunium oxide produced from the additional feed solution was equivalent to the original neptunium oxide and within the content description of the Letter of Amendment.
Watkins, R.; Jordan, J.; Hensel, S.
Two Dimensional Polymer That Generates Nitric Oxide.
A polymeric composition that generates nitric oxide and a process for rendering the surface of a substrate nonthrombogenic by applying a coating of the polymeric composition to the substrate are disclosed. The composition comprises: (1) a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, and (ii) a crosslinking agent containing functional groups capable of reacting with the amino groups; and (2) a plurality of nitric oxide generating functional groups associated with the crosslinked chemical combination. Once exposed to a physiological environment, the coating generates nitric oxide thereby inhibiting platelet aggregation. In one embodiment, the nitric oxide generating functional groups are provided by a nitrated compound (e.g., nitrocellulose) imbedded in the polymeric composition. In another embodiment, the nitric oxide generating functional groups comprise N2O2- groups covalently bonded to amino groups on the polymer.
McDonald, William F. (Utica, OH); Koren, Amy B. (Lansing, MI)
Simultaneous removal of nitrogen oxides and sulfur oxides from combustion gases
A process for the simultaneous removal of sulfur oxides and nitrogen oxides from power plant stack gases comprising contacting the stack gases with a supported iron oxide catalyst/absorbent in the presence of sufficient reducing agent selected from the group consisting of carbon monoxide, hydrogen, and mixtures thereof, to provide a net reducing atmosphere in the SO.sub.x /NO.sub.x removal zone. The sulfur oxides are removed by absorption substantially as iron sulfide, and nitrogen oxides are removed by catalytic reduction to nitrogen and ammonia. The spent iron oxide catalyst/absorbent is regenerated by oxidation and is recycled to the contacting zone. Sulfur dioxide is also produced during regeneration and can be utilized in the production of sulfuric acid and/or sulfur.
Clay, David T. (Longview, WA); Lynn, Scott (Walnut Creek, CA)
Characterization of a transient +2 sulfur oxidation state intermediate from the oxidation of aqueous sulfide
The oxidation H{sub 2}S to sulfate involves a net transfer of eight electrons and occurs through the formation of several partially oxidized intermediates with oxidation states ranging from {minus}1 to +5. Known intermediates include elemental sulfur (oxidation state 0), polysulfides (outer sulfur: {minus}1, inner sulfur: 0), sulfite (+4) and thiosulfate (outer sulfur: {minus}1, inner sulfur: +5). A noticeable gap in this series of intermediates is that of a +2 sulfur oxidation state oxoacid/oxoanion species, which was never detected experimentally. Here, we present evidence of the transient existence of +2 oxidation state intermediate in the Ni(II)-catalyzed oxidation of aqueous sulfide. X-ray absorption near-edge structure (XANES) spectroscopy and Fourier-transform-infrared (FT-IR) spectroscopy were used to characterize this species; they suggest that it has a sulfoxylate ion (SO{sub 2}{sup 2{minus}}) structure.
Vairavmurthy, M.A.; Zhou, Weiqing
Chemically Modified Metal Oxide Nanostructure for Photoelectrochemical Water Splitting
nanoparticle seeded indium-tin oxide (ITO) substrate usingarrays were grown on an indium-tin oxide substrate followedof a double-sided indium-tin-oxide (ITO) glass substrate
Wang, Gongming
Induction of enhanced methane oxidation in compost: Temperature and moisture response
Landfilling is one of the most common ways of municipal solid waste disposal. Degradation of organic waste produces CH{sub 4} and other landfill gases that significantly contribute to global warming. However, before entering the atmosphere, part of the produced CH{sub 4} can be oxidised while passing through the landfill cover. In the present study, the oxidation rate of CH{sub 4} was studied with various types of compost as possible landfill cover. The influence of incubation time, moisture content and temperature on the CH{sub 4} oxidation capacity of different types of compost was examined. It was observed that the influence of moisture content and temperature on methane oxidation is time-dependent. Maximum oxidation rates were observed at moisture contents ranging from 45% to 110% (dry weight basis), while the optimum temperature ranged from 15 to 30 deg. C.
Mor, Suman [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016 (India) and Department of Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium)]. E-mail: email@example.com; Visscher, Alex de [Department of Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Ravindra, Khaiwal [Micro and Trace Analysis Centre, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Dahiya, R.P. [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016 (India); Chandra, A. [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110016 (India); Cleemput, Oswald van [Department of Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium)
Bulk Gold-Catalyzed Reactions of Isocyanides, Amines, and Amine N-Oxides
Bulk gold powder (5¢50 ?m particles) catalyzes the reactions of isocyanides with amines and amine N-oxides to produce ureas. The reaction of n-butyl isocyanide (nBu¢N?C) with di-n-propylamine and N-methylmorpholine N-oxide in acetonitrile, which was studied in the greatest detail, produced 3-butyl-1,1-dipropylurea (O?C(NHnBu)(NnPr2)) in 99% yield at 60 ░C within 2 h. Sterically and electronically different isocyanides, amines, and amine N-oxides react successfully under these conditions. Detailed studies support a two-step mechanism that involves a gold-catalyzed reaction of adsorbed isocyanide with the amine N-oxide to form an isocyanate (RN?C?O), which rapidly reacts with the amine to give the urea product. These investigations show that bulk gold, despite its reputation for poor catalytic activity, is capable of catalyzing these reactions.
Klobukowski, Erik; Angelici, Robert; Woo, Keith L.
Electrical and physical characteristics of HfLaON-gated metal-oxide-semiconductor capacitors with various nitrogen concentration profiles
The comparative studies of electrical and physical characteristics of HfLaON-gated metal-oxide-semiconductor (MOS) capacitors with various nitrogen concentration profiles (NCPs) were investigated. Various NCPs in HfLaON gate dielectrics were adjusted ... Keywords: Charge trapping, Current-conduction, High-k dielectric, Metal-oxide-semiconductor (MOS), Nitrogen concentration profiles (NCPs)
Chin-Lung Cheng; Jeng-Haur Horng; Hung-Yang Tsai
Influence of Alloy Microstructure on Oxide Growth in HCM12A in Supercritical Water Jeremy Bischoff1
corrosion resistance. Because of their radiation and stress corrosion cracking resistance, ferritic to oxidation appears to enhance the corrosion resistance of the alloy [2]. In the present study, HCM12A samples on the corrosion resistance but these results are not shown in this article. The oxide layers formed on HCM12A
Final Report for DOE grant no. DE-FG02-04ER63883: Can soil genomics predict the impact of precipitation on nitrous oxide flux from soil
Nitrous oxide is a potent greenhouse gas that is released by microorganisms in soil. However, the production of nitrous oxide in soil is highly variable and difficult to predict. Future climate change may have large impacts on nitrous oxide release through alteration of precipitation patterns. We analyzed DNA extracted from soil in order to uncover relationships between microbial processes, abundance of particular DNA sequences and net nitrous oxide fluxes from soil. Denitrification, a microbial process in which nitrate is used as an electron acceptor, correlated with nitrous oxide flux from soil. The abundance of ammonia oxidizing archaea correlated positively, but weakly, with nitrous oxide production in soil. The abundance of bacterial genes in soil was negatively correlated with gross nitrogen mineralization rates and nitrous oxide release from soil. We suggest that the most important control over nitrous oxide production in soil is the growth and death of microorganisms. When organisms are growing nitrogen is incorporated into their biomass and nitrous oxide flux is low. In contrast, when microorganisms die, due to predation or infection by viruses, inorganic nitrogen is released into the soil resulting in nitrous oxide release. Higher rates of precipitation increase access to microorganisms by predators or viruses through filling large soil pores with water and therefore can lead to large releases of nitrous oxide from soil. We developed a new technique, stable isotope probing with 18O-water, to study growth and mortality of microorganisms in soil.
Egbert Schwartz
Photodissociation Dynamics of Halogen Oxide Species
The focus of this dissertation is the study of the photodissociation dynamics of halogen oxide species (XO, X = Cl, Br, I). These radical species are known to be important in stratospheric and tropospheric ozone depletion cycles. They are also useful benchmark systems for the comparison to current theoretical methods where they provide insight into the dynamics occurring beyond the Franck-Condon region. These systems are studied using velocity map ion imaging, a technique that measures velocity and angular information simultaneously. Photofragment species are state-selectively ionized for detection using 2+1 REMPI (Resonance Enhanced Multi-Photon Ionization). The instrumentation employs a molecular beam of the XO radicals formed using pyrolitic and photolytic methods. The current work involves the measurement of fundamental physical constants of the XO species. The bond dissociation energy of IO is measured. Vibrational level dependent correlated final state branching ratios of the predissociation of the A(^2 II_3/2) state of ClO and BrO are reported, and comparison to theoretical methods is discussed.
Dooley, Kristin S.
Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials
The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm{sup -3}, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH{sub 4} m{sup -2} d{sup -1}, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH{sub 4} m{sup -2} d{sup -1} and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material.
Rachor, Ingke, E-mail: email@example.com [University of Hamburg, Institute of Soil Science, Allende-Platz 2, 20146 Hamburg (Germany); Gebert, Julia; Groengroeft, Alexander; Pfeiffer, Eva-Maria [University of Hamburg, Institute of Soil Science, Allende-Platz 2, 20146 Hamburg (Germany)
Selective methane oxidation over promoted oxide catalysts. Quarterly technical progress report, September 8, 1992--November 30, 1992
Support effects on catalytic reactions, especially of highly exothermic oxidation reactions, can be very significant. Since we had shown that a MoO{sub 3}/SiO{sub 2} catalyst, especially when used in a double bed configuration with a Sr/La{sub 2}O{sub 3} catalyst, can selectively oxidize methane to formaldehyde, the role of the SiO{sub 2} support was investigated. Therefore, partial oxidation of methane by oxygen to form formaldehyde, carbon oxides, and C{sub 2} products (ethane and ethene) has been studied over silica catalyst supports (fumed Cabosil and Grace 636 silica gel) in the 630-780{degrees}C temperature range under ambient pressure. When relatively high gas hourly space velocities (GHSV) were utilized, the silica catalysts exhibit high space time yields (at low conversions) for methane partial oxidation to formaldehyde, and the C{sub 2} hydrocarbons were found to be parallel products with formaldehyde. In general, the selectivities toward CO were high while those toward CO{sub 2} were low. Based on the present results obtained by a double catalyst bed experiment, the observations of product composition dependence on the variation of GHSV (i.e. gas residence time), and differences in apparent activation energies of formation of C{sub 2}H{sub 6}, and CH{sub 2}O, a reaction mechanism is proposed for the activation of methane over the silica surface. This mechanism can explain the observed product distribution patterns (specifically the parallel formation of formaldehyde and C{sub 2} hydrocarbons).
Klier, K.; Herman, R.G.; Sun, Q.; Sarkany, J.
Structure formation upon reactive direct current magnetron sputtering of transition metal oxide films
A comparative study of reactive direct current magnetron sputtering for different transition metal oxides reveals crystalline films at room temperature for group 4 and amorphous films for groups 5 and 6. This observation cannot be explained by the known growth laws and is attributed to the impact of energetic particles, originating from the oxidized target, on the growing film. This scenario is supported by measured target characteristics, the evolution of deposition stress of the films, and the observed backsputtering.
Ngaruiya, J.M.; Kappertz, O.; Mohamed, S.H.; Wuttig, M. [I. Physikalisches Institut der RWTH Aachen, D-52056 Aachen, Germany and Jomo Kenyatta University of Agriculture and Technology, Box 62000 Nairobi (Kenya); I. Physikalisches Institut der RWTH Aachen, D-52056 Aachen (Germany)
Enzymes of respiratory iron oxidation. Progress report, March 1990--June 1992
Blake, R. II
Advanced Oxidation Techniques for Soils Containing Manufactured Gas Plant (MGP) Hydrocarbons
This report presents the results of a bench-scale experimental study using a combination of chemical oxidation and electrotreatment of PAH contaminated soils from former Manufactured Gas Plant (MGP) sites. Electroosmotic movement of water and movement of charged surfactant micelles due to the electro-gradient were used to introduce persulfate oxidant into the contaminated soil matrix. Results showed that greater than 80% removal of the PAHs were obtained in 20 days of treatment time. Experiments with aqu...
Quantitative X-ray microanalysis of submicron carbide formation in chromium (III) oxide rich scale
This paper discusses the chemical microanalysis techniques adapted to identify the precipitates that form on the surface of, or within, the oxide scale of a Fe-22Cr ferritic steel during exposure to a carbon-monoxide rich environment at 750C for 800 hours. Examination of oxidized test coupons revealed the presence of a fiber like structure at the surface, shown in figure 1. Other studies have reported that these structures are carbon precipitates.
Collins, W.K.; Ziomek-Moroz, M.; Holcomb, G.R.; Danielson, P.; Hunt, A.H
CO Oxidation mechanism on CeO2-supported Au nanoclusters
To reveal the richer chemistry of CO oxidation by CeO2 supported Au Nanoclusters(NCs)/Nanoparticles, we design Au13 and Au12 supported on a flat and a stepped-CeO2 model (Au/CeO2) and study various kinds of CO oxidation mechanisms at the Au-CeO2 interface and the Au NC as well.
Kim H. Y.; Henkelman, G.
CRAD, Criticality Safety - Y-12 Enriched Uranium Operations Oxide...
Y-12 Enriched Uranium Operations Oxide Conversion Facility CRAD, Criticality Safety - Y-12 Enriched Uranium Operations Oxide Conversion Facility January 2005 A section of Appendix...
CRAD, Safety Basis - Y-12 Enriched Uranium Operations Oxide Conversion...
Y-12 Enriched Uranium Operations Oxide Conversion Facility CRAD, Safety Basis - Y-12 Enriched Uranium Operations Oxide Conversion Facility January 2005 A section of Appendix C to...
CRAD, Management - Y-12 Enriched Uranium Operations Oxide Conversion...
Y-12 Enriched Uranium Operations Oxide Conversion Facility CRAD, Management - Y-12 Enriched Uranium Operations Oxide Conversion Facility January 2005 A section of Appendix C to DOE...
CRAD, Training - Y-12 Enriched Uranium Operations Oxide Conversion...
Y-12 Enriched Uranium Operations Oxide Conversion Facility CRAD, Training - Y-12 Enriched Uranium Operations Oxide Conversion Facility January 2005 A section of Appendix C to DOE G...
CRAD, DOE Oversight - Y-12 Enriched Uranium Operations Oxide...
Y-12 Enriched Uranium Operations Oxide Conversion Facility CRAD, DOE Oversight - Y-12 Enriched Uranium Operations Oxide Conversion Facility January 2005 A section of Appendix C to...
A method is presented for oxidizing plutonium from the tetravalent state to the hexavalent state by means of bismuthate oxidizing agents.
Garner, C.S.
Template synthesis and surface modification of metal oxides.
??Porous metal oxide monoliths, specifically silica, titania, zirconia and mixed oxides containing aluminum and yttrium, were prepared in a one-pot synthesis. Macroporosity was induced usingģ (more)
Drisko, Glenna Lynn
Process, Synthesis, and Application of Functional Oxides II
Oct 19, 2010 ... Nanostructured Functional Oxide Thin Films for High Temperature Superconductors, Solid Oxide Fuel Cells and Solar Cells: Haiyan Wang1;Ā...
Iron catalysis in oxidation by ozone - Energy Innovation Portal
Bookmark Iron catalysis in oxidation by ozone - Energy Innovation Portal on Google; Bookmark Iron catalysis in oxidation by ozone - Energy Innovation ...
AP-XPS Measures MIEC Oxides in Action
and oxygen ions. MIEC oxides have broad applications, including use in solid-oxide fuel cells, high-temperature electrolysis for synthetic fuel production, and...