National Library of Energy BETA

Sample records for ther mal decomposition

  1. Investigation of the physical properties of the tetragonal CeMAl4Si2...

    Office of Scientific and Technical Information (OSTI)

    the tetragonal CeMAl4Si2 (M Rh, Ir, Pt) compounds Prev Next Title: Investigation of the physical properties of the tetragonal CeMAl4Si2 (M Rh, Ir, Pt) compounds The ...

  2. Step-by-step thermal transformations of a new porous coordination polymer [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} (Me{sub 2}mal{sup 2-}=dimethylmalonate): Thermal degradation to barium cuprate

    SciTech Connect (OSTI)

    Zauzolkova, Natalya; Dobrokhotova, Zhanna; Lermontov, Anatoly; Zorina, Ekaterina; Emelina, Anna; Bukov, Mikhail; Sidorov, Aleksey; Kiskin, Mikhail; Bogomyakov, Artem; Lytvynenko, Anton; Kolotilov, Sergey; Velikodnyi, Yuriy; Kovba, Maksim

    2013-01-15

    The reactions of CuSO{sub 4}{center_dot}5H{sub 2}O, dimethylmalonic acid and Ba(OH){sub 2}{center_dot}H{sub 2}O (Cu: H{sub 2}Me{sub 2}mal: Ba=1: 2: 2) in aqueous and aqueous-ethanol solutions (H{sub 2}O: EtOH=1: 1) resulted in formation of 3D-porous coordination polymers [(H{sub 2}O){sub 3}({mu}-H{sub 2}O){sub 2}CuBa({mu}{sub 3}-Me{sub 2}mal)(Me{sub 2}mal)]{sub n} (1) and [({mu}-H{sub 2}O)CuBa({mu}{sub 3}-Me{sub 2}mal)({mu}{sub 4}-Me{sub 2}mal)]{sub n} (2), respectively. It has been shown that compound 2 was an intermediate in the thermal degradation of compound 1. Thorough studies of solid-state thermolysis of 1 and 2 allowed to detect formation of coordination polymer [CuBa({mu}{sub 4}-Me{sub 2}mal)({mu}{sub 5}-Me{sub 2}mal)]{sub n} (3), structure of which was determined by X-ray powder diffraction. It has been found that the channels in polymer 3 were accessible for guest molecules (MeOH). Theoretical estimation of methanol diffusion barrier was carried out. Complete solid-phase thermolysis of 1 and 2 leads to a mixture of BaCuO{sub 2}, BaCO{sub 3}, and CuO. Special conditions for obtaining of a crystalline phase of pure cubic BaCuO{sub 2} were determined. - Graphical abstract: Step-by-step transformation of new coordination polymer [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} to [(H{sub 2}O)CuBa(Me{sub 2}mal){sub 2}]{sub n} and [CuBa(Me{sub 2}mal){sub 2}]{sub n} were performed. Dehydration of initial compound leads to structural changes of 12-membered ring fragment. All compounds have porous structure. The final product of thermal decomposition is crystalline phase of individual cubic BaCuO{sub 2}. Highlights: Black-Right-Pointing-Pointer New 3D-polymers [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} and [(H{sub 2}O)CuBa(Me{sub 2}mal){sub 2}]{sub n} were synthesized. Black-Right-Pointing-Pointer Thermal analysis showed step-by-step transformations of [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n}. Black-Right-Pointing-Pointer Crystalline

  3. Continuous radiant decomposition studies

    SciTech Connect (OSTI)

    Tabatabaie-Raissi, A.; Antal, M.J. Jr.

    1983-01-01

    To support ongoing research activities of the Renewable Resources Research Laboratory (R/sup 3/L), a double paraboloid downward facing beam arc image furnace was designed and fabricated in Princeton. The solar simulator was currently modified and upgraded to incorporate a 30 KW water-cooled, xenon compact arc lamp with all the associated electrical, optical and cooling systems. The solar furnace provides an intense light beam with a peak flux density as high as 1000 W/cm/sup 2/ (or 10,000 suns) at the focus of the concentrator. The parameters governing the design and operation of this solar furnace are described in detail. Considerable progress was made in the development of novel spouted/fluidized bed flash pyrolysis reactors which function as solar receivers. The reactors were employed at the focus of the arc image furnace under conditions of severe radiant energy transfer (with peak flux of about 1 KW/cm/sup 2/). The pyrolysis reactors employed under continuous radiant decomposition conditions performed well and provided sirup yields as high as 55% (by weight) using crushed corn cob particles (1000 > dp > 850 ..mu..m). Finally, an extensive literature search was carried out to compile the currently available data regarding decomposition of zinc sulfate. Several experiments using a Setaram Differential Scanning Calorimeter were preformed in order to investigate the mechanisms of ZnSO/sub 4/ decomposition under conditions of low heating rates.

  4. Hydrogen iodide decomposition

    DOE Patents [OSTI]

    O'Keefe, Dennis R.; Norman, John H.

    1983-01-01

    Liquid hydrogen iodide is decomposed to form hydrogen and iodine in the presence of water using a soluble catalyst. Decomposition is carried out at a temperature between about 350.degree. K. and about 525.degree. K. and at a corresponding pressure between about 25 and about 300 atmospheres in the presence of an aqueous solution which acts as a carrier for the homogeneous catalyst. Various halides of the platinum group metals, particularly Pd, Rh and Pt, are used, particularly the chlorides and iodides which exhibit good solubility. After separation of the H.sub.2, the stream from the decomposer is countercurrently extracted with nearly dry HI to remove I.sub.2. The wet phase contains most of the catalyst and is recycled directly to the decomposition step. The catalyst in the remaining almost dry HI-I.sub.2 phase is then extracted into a wet phase which is also recycled. The catalyst-free HI-I.sub.2 phase is finally distilled to separate the HI and I.sub.2. The HI is recycled to the reactor; the I.sub.2 is returned to a reactor operating in accordance with the Bunsen equation to create more HI.

  5. Erbium hydride decomposition kinetics.

    SciTech Connect (OSTI)

    Ferrizz, Robert Matthew

    2006-11-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  6. Ther FERMI FEL project at TRIESTE

    SciTech Connect (OSTI)

    Walker, R.P.; Bulfone, D.; Cargnello, F.

    1995-12-31

    The goal of the FERMI project - Free Electron Radiation and Matching Instrumentation - is to construct a new user facility for FEL radiation beams covering a broad spectral range (2-250 {mu}m) to complement the high brightness VUV/Soft-Xray radiation available from the ELETTRA synchrotron radiation facility at Trieste. A unique feature of the project will be the possibility of carrying out {open_quote}pump-probe{close_quote} experiments using synchronized radiation beams from FERMI and ELETTRA on the same sample. The project was launched at a meeting with Italian FEL experts held in Trieste on the 18th November 1994, chaired by C. Rubbia, as a collaboration between Sincrotrone Trieste, ENEA (Frascati), INFN (Frascati) and the University of Naples (Department of Electronic Engineering). The facility will make use of an existing linac, that forms part of the ELETTRA injection system, and a hall into which the beam can be extracted. In addition, for the first phase of the project equipment will be used from the suspended INFN/ENEA {open_quote}SURF{close_quote} FEL experiment, including the undulator, beam transport magnets and optical cavity. In this first International FEL Conference report on the project, we summarize the main features of the project, concentrating in particular on the most recent activities, including: results of measurements of the linac beam in the FEL mode of operation, further studies of the electron beam transport system including possibilities for bunch length manipulations, and further numerical calculations of the FEL performance.

  7. Anisotropic decomposition of energetic materials

    SciTech Connect (OSTI)

    Pravica, Michael; Quine, Zachary; Romano, Edward; Bajar, Sean; Yulga, Brian; Yang Wenge; Hooks, Daniel

    2007-12-12

    Using a white x-ray synchrotron beam, we have dynamically studied radiation-induced decomposition in single crystalline PETN and TATB. By monitoring the integrated intensity of selected diffraction spots via a CCD x-ray camera as a function of time, we have found that the decomposition rate varies dramatically depending upon the orientation of the crystalline axes relative to polarized x-ray beam and for differing diffracting conditions (spots) within the same crystalline orientation. We suggest that this effect is due to Compton scattering of the polarized x-rays with electron clouds that is dependent upon their relative orientation. This novel effect may yield valuable insight regarding anisotropic detonation sensitivity in energetic materials such as PETN.

  8. Anisotropic Decomposition of Energetic Materials

    SciTech Connect (OSTI)

    Pravica, Michael; Quine, Zachary; Romano, Edward; Bajar, Sean; Yulga, Brian; Yang, Wenge; Hooks, Daniel

    2008-01-17

    Using a white x-ray synchrotron beam, we have dynamically studied radiation-induced decomposition in single crystalline PETN and TATB. By monitoring the integrated intensity of selected diffraction spots via a CCD x-ray camera as a function of time, we have found that the decomposition rate varies dramatically depending upon the orientation of the crystalline axes relative to polarized x-ray beam and for differing diffracting conditions (spots) within the same crystalline orientation. We suggest that this effect is due to Compton scattering of the polarized x-rays with electron clouds that is dependent upon their relative orientation. This novel effect may yield valuable insight regarding anisotropic detonation sensitivity in energetic materials such as PETN.

  9. Decomposition Studies of Tetraphenylborate Slurries

    SciTech Connect (OSTI)

    Crawford, C.L.

    1997-05-06

    This report details the decomposition of aqueous (K,Na) slurries in concentrated salt solutions using a more complete candidate catalyst recipe, extended testing temperatures (40-70 degrees C) and test durations of approximately 1500 hours (9 weeks). This study uses recently developed High-Pressure Liquid Chromatography (HPLC) methods for analysis of tetraphenylborate (TPB-), triphenylborane (3PB) and diphenylborinic acid (2PB). All of the present tests involve non-radioactive simulants and do not include investigations of radiolysis effects.

  10. Investigation of the physical properties of the tetragonal CeMAl4Si2 (M = Rh, Ir, Pt) compounds

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

    Ghimire, N. J.; Ronning, F.; Williams, D. J.; Scott, B. L.; Luo, Yongkang; Thompson, J. D.; Bauer, E. D.

    2014-12-15

    The synthesis, crystal structure and physical properties studied by means of x-ray diffraction, magnetic, thermal and transport measurements of CeMAl4Si2 (M = Rh, Ir, Pt) are reported, along with the electronic structure calculations for LaMAl4Si2 (M = Rh, Ir, Pt). These materials adopt a tetragonal crystal structure (space group P4/mmm) comprised of BaAl4 blocks, separated by MAl2 units, stacked along the c-axis. Both CeRhAl4Si2 and CeIrAl4Si2 order antiferromagnetically below TN1 = 14 and 16 K, respectively, and undergo a second antiferromagnetic transitition at lower temperature (TN2 = 9 and 14 K, respectively). CePtAl4Si2 orders ferromagnetically below TC = 3 Kmore » with an ordered moment of μsat = 0.8 μB for a magnetic field applied perpendicular to the c-axis. Electronic structure calculations reveal quasi-2D character of the Fermi surface.« less

  11. Manganese Reduction-Oxidation Drives Plant Debris Decomposition

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

    Manganese Reduction-Oxidation Drives Plant Debris Decomposition Print Microbial decomposition of plant debris ("litter") is a keystone ecosystem process because it regulates ...

  12. Unimolecular decomposition of methyltrichlorosilane: RRKM calculations

    SciTech Connect (OSTI)

    Osterheld, T.H.; Allendorf, M.D.; Melius, C.F.

    1993-06-01

    Based on reaction thermochemistry and estimates of Arrhenius A-factors, it is expected that Si-C bond cleavage, C-H bond cleavage, and HCl elimination will be the primary channels for the unimolecular decomposition of methyltrichlorosilane. Using RRKM theory, we calculated rate constants for these three reactions. The calculations support the conclusion that these three reactions are the major decomposition pathways. Rate constants for each reaction were calculated in the high-pressure limit (800--1500 K) and in the falloff regime (1300--1500 K) for bath gases of both helium and hydrogen. These calculations thus provide branching fractions as well as decomposition rates. We also calculated bimolecular rate constants for the overall decomposition in the low-pressure limit. Interesting and surprising kinetic behavior of this system and the individual reactions is discussed. The reactivity of this chlorinated organosilane is compared to that of other organosilanes.

  13. Decomposition of forest products buried in landfills

    SciTech Connect (OSTI)

    Wang, Xiaoming; Padgett, Jennifer M.; Powell, John S.; Barlaz, Morton A.

    2013-11-15

    Highlights: • This study tracked chemical changes of wood and paper in landfills. • A decomposition index was developed to quantify carbohydrate biodegradation. • Newsprint biodegradation as measured here is greater than previous reports. • The field results correlate well with previous laboratory measurements. - Abstract: The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5 yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C + H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C + H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27 g OC g{sup −1} dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than

  14. Modeling decomposition of rigid polyurethane foam

    SciTech Connect (OSTI)

    Hobbs, M.L.

    1998-01-01

    Rigid polyurethane foams are used as encapsulants to isolate and support thermally sensitive components within weapon systems. When exposed to abnormal thermal environments, such as fire, the polyurethane foam decomposes to form products having a wide distribution of molecular weights and can dominate the overall thermal response of the system. Decomposing foams have either been ignored by assuming the foam is not present, or have been empirically modeled by changing physical properties, such as thermal conductivity or emissivity, based on a prescribed decomposition temperature. The hypothesis addressed in the current work is that improved predictions of polyurethane foam degradation can be realized by using a more fundamental decomposition model based on chemical structure and vapor-liquid equilibrium, rather than merely fitting the data by changing physical properties at a prescribed decomposition temperature. The polyurethane decomposition model is founded on bond breaking of the primary polymer and formation of a secondary polymer which subsequently decomposes at high temperature. The bond breaking scheme is resolved using percolation theory to describe evolving polymer fragments. The polymer fragments vaporize according to individual vapor pressures. Kinetic parameters for the model were obtained from Thermal Gravimetric Analysis (TGA) from a single nonisothermal experiment with a heating rate of 20 C/min. Model predictions compare reasonably well with a separate nonisothermal TGA weight loss experiment with a heating rate of 200 C/min.

  15. Decomposition of amino diazeniumdiolates (NONOates): Molecular mechanisms

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

    Shaikh, Nizamuddin; Valiev, Marat; Lymar, Sergei V.

    2014-08-23

    Although diazeniumdiolates (X[N(O)NO]-) are extensively used in biochemical, physiological, and pharmacological studies due to their ability to release NO and/or its congeneric nitroxyl, the mechanisms of these processes remain obscure. In this work, we used a combination of spectroscopic, kinetic, and computational techniques to arrive at a quantitatively consistent molecular mechanism for decomposition of amino diazeniumdiolates (amino NONOates: R2N[N(O)NO]-, where R = —N(C2H5)2(1), —N(C3H4NH2)2(2), or —N(C2H4NH2)2(3)). Decomposition of these NONOates is triggered by protonation of their [NN(O)NO]- group with the apparent pKa and decomposition rate constants of 4.6 and 1 s-1 for 1; 3.5 and 0.083 s-1 for 2; andmore » 3.8 and 0.0033 s-1 for 3. Although protonation occurs mainly on the O atoms of the functional group, only the minor R2N(H)N(O)NO tautomer (population ~ 10-7, for 1) undergoes the N—N heterolytic bond cleavage (kd ~ 107 s-1 for 1) leading to amine and NO. Decompositions of protonated amino NONOates are strongly temperature-dependent; activation enthalpies are 20.4 and 19.4 kcal/mol for 1 and 2, respectively, which includes contributions from both the tautomerization and bond cleavage. Thus, the bond cleavage rates exhibit exceptional sensitivity to the nature of R substituents which strongly modulate activation entropy. At pH < 2, decompositions of all three NONOates that have been investigated are subject to additional acid catalysis that occurs through di-protonation of the [NN(O)NO]- group.« less

  16. Decomposition of Amino Diazeniumdiolates (NONOates): Molecular Mechanisms

    SciTech Connect (OSTI)

    Shaikh, Nizamuddin; Valiev, Marat; Lymar, Sergei V.

    2014-08-23

    Although diazeniumdiolates (X[N(O)NO]-) are extensively used in biochemical, physiological, and pharmacological studies due to their ability to slowly release NO and/or its congeneric nitroxyl, the mechanisms of these processes remain obscure. In this work, we used a combination of spectroscopic, kinetic, and computational techniques to arrive at a qualitatively consistent molecular mechanism for decomposition of amino diazeniumdiolates (amino NONOates: R2N[N(O)NO]-, where R = -N(C2H5)2 (1), -N(C3H4NH2)2 (2), or -N(C2H4NH2)2 (3)). Decomposition of these NONOates is triggered by protonation of their [NN(O)NO]- group with apparent pKa and decomposition rate constants of 4.6 and 1 s-1 for 1-H, 3.5 and 83 x 10-3 s-1 for 2-H, and 3.8 and 3.3 x 10-3 s-1 for 3-H. Although protonation occurs mainly on the O atoms of the functional group, only the minor R2N(H)N(O)NO tautomer (population ~0.01%, for 1) undergoes the N-N heterolytic bond cleavage (k ~102 s-1 for 1) leading to amine and NO. Decompositions of protonated amino NONOates are strongly temperature-dependent; activation enthalpies are 20.4 and 19.4 kcal/mol for 1 and 2, respectively, which includes contributions from both the tautomerization and bond cleavage. The bond cleavage rates exhibit exceptional sensitivity to the nature of R substituents which strongly modulate activation entropy. At pH < 2, decompositions of all these NONOates are subject to additional acid catalysis that occurs through di-protonation of the [NN(O)NO]- group.

  17. Adomian Decomposition Method for Quark Gluon Plasma Model

    SciTech Connect (OSTI)

    Constantinescu, Radu; Ionescu, Carmen; Stoicescu, Mihai

    2011-10-03

    The paper investigates the possibility of obtaining analytical solutions for the Quark Gluon Plasma model using the Adomian decomposition method.

  18. Manganese Reduction-Oxidation Drives Plant Debris Decomposition

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

    Manganese Reduction-Oxidation Drives Plant Debris Decomposition Manganese Reduction-Oxidation Drives Plant Debris Decomposition Print Monday, 22 February 2016 00:00 Microbial decomposition of plant debris ("litter") is a keystone ecosystem process because it regulates nutrient availability, ecosystem productivity, and carbon (C) cycling. Historically, climate (primarily temperature and precipitation) has been thought to regulate the rate of litter decomposition, which then influences

  19. ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

    SciTech Connect (OSTI)

    Ketusky, E.; Subramanian, K.

    2012-02-29

    At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to be well demonstrated. In addition, as AOPs are considered to be 'green' their use enables any net chemical additions to the waste to be minimized. In order to test the ability to decompose the oxalate and determine the decomposition rates, a test rig was designed, where 10 vol% ozone would be educted into a spent oxalic acid decomposition loop, with the loop maintained at 70 C and recirculated at 40L/min. Each of the spent oxalic acid streams would be created from three oxalic acid strikes of an F-area simulant (i.e., Purex = high Fe/Al concentration) and H-area simulant (i.e., H area modified Purex = high Al/Fe concentration) after nearing

  20. Domain decomposition multigrid for unstructured grids

    SciTech Connect (OSTI)

    Shapira, Yair

    1997-01-01

    A two-level preconditioning method for the solution of elliptic boundary value problems using finite element schemes on possibly unstructured meshes is introduced. It is based on a domain decomposition and a Galerkin scheme for the coarse level vertex unknowns. For both the implementation and the analysis, it is not required that the curves of discontinuity in the coefficients of the PDE match the interfaces between subdomains. Generalizations to nonmatching or overlapping grids are made.

  1. Perspectives on Pentaerythritol Tetranitrate (PETN) Decomposition

    SciTech Connect (OSTI)

    Chambers, D; Brackett, C; Sparkman, D O

    2002-07-01

    This report evaluates the large body of work involving the decomposition of PETN and identifies the major decomposition routes and byproducts. From these studies it becomes apparent that the PETN decomposition mechanisms and the resulting byproducts are primarily determined by the chemical environment. In the absence of water, PETN can decompose through the scission of the O-NO{sup 2} bond resulting in the formation of an alkoxy radical and NO{sub 2}. Because of the relatively high reactivity of both these initial byproducts, they are believed to drive a number of autocatalytic reactions eventually forming (NO{sub 2}OCH{sub 2}){sub 3}CCHO, (NO{sub 2}OCH{sub 2}){sub 2}C=CHONO{sub 2}, NO{sub 2}OCH=C=CHONO{sub 2}, (NO{sub 2}OCH{sub 2}){sub 3}C-NO{sub 2}, (NO{sub 2}OCH{sub 2}){sub 2}C(NO{sub 2}){sub 2}, NO{sub 2}OCH{sub 2}C(NO{sub 2}){sub 3}, and C(NO{sub 2}){sub 4} as well as polymer-like species such as di-PEHN and tri-PEON. Surprisingly, the products of many of these proposed autocatalytic reactions have never been analytically validated. Conversely, in the presence of water, PETN has been shown to decompose primarily to mono, di, and tri nitrates of pentaerythritol.

  2. Decomposition of amino diazeniumdiolates (NONOates): Molecular mechanisms

    SciTech Connect (OSTI)

    Shaikh, Nizamuddin; Valiev, Marat; Lymar, Sergei V.

    2014-12-01

    Although diazeniumdiolates (X[N(O)NO]-) are extensively used in biochemical, physiological, and pharmacological studies due to their ability to release NO and/or its congeneric nitroxyl, the mechanisms of these processes remain obscure. In this work, we used a combination of spectroscopic, kinetic, and computational techniques to arrive at a quantitatively consistent molecular mechanism for decomposition of amino diazeniumdiolates (amino NONOates: R2N[N(O)NO]-, where R = N(C2H5)2(1), N(C3H4NH2)2(2), or N(C2H4NH2)2(3)). Decomposition of these NONOates is triggered by protonation of their [NN(O)NO]- group with the apparent pKa and decomposition rate constants of 4.6 and 1 s-1 for 1; 3.5 and 0.083 s-1 for 2; and 3.8 and 0.0033 s-1 for 3. Although protonation occurs mainly on the O atoms of the functional group, only the minor R2N(H)N(O)NO tautomer (population ~ 10-7, for 1) undergoes the NN heterolytic bond cleavage (kd ~ 107 s-1 for 1) leading to amine and NO. Decompositions of protonated amino NONOates are strongly temperature-dependent; activation enthalpies are 20.4 and 19.4 kcal/mol for 1 and 2, respectively, which includes contributions from both the tautomerization and bond cleavage. The bond cleavage rates exhibit exceptional sensitivity to the nature of R substituents which strongly modulate activation entropy. At pH < 2, decompositions of all three NONOates that have been investigated are subject to additional acid catalysis that occurs through di-protonation of the [NN(O)NO]- group.

  3. Radiation-induced decomposition of PETN and TATB under pressure

    SciTech Connect (OSTI)

    Giefers, Hubertus; Pravica, Michael; Liermann, Hanns-Peter; Yang, Wenge

    2008-10-02

    We have investigated decomposition of PETN and TATB induced by white synchrotron X-ray radiation in a diamond anvil cell at ambient temperature and two pressures, nearly ambient and about 6 GPa. The decomposition rate of TATB decreases significantly when it is pressurized to 5.9 GPa. The measurements were highly reproducible and allowed us to obtain decomposition rates and the order parameters of the reactions.

  4. Manganese Reduction-Oxidation Drives Plant Debris Decomposition

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

    Manganese Reduction-Oxidation Drives Plant Debris Decomposition Print Microbial decomposition of plant debris ("litter") is a keystone ecosystem process because it regulates nutrient availability, ecosystem productivity, and carbon (C) cycling. Historically, climate (primarily temperature and precipitation) has been thought to regulate the rate of litter decomposition, which then influences the rate at which nutrients become available and C contained in the litter is released back into

  5. Manganese Reduction-Oxidation Drives Plant Debris Decomposition

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

    Manganese Reduction-Oxidation Drives Plant Debris Decomposition Print Microbial decomposition of plant debris ("litter") is a keystone ecosystem process because it regulates nutrient availability, ecosystem productivity, and carbon (C) cycling. Historically, climate (primarily temperature and precipitation) has been thought to regulate the rate of litter decomposition, which then influences the rate at which nutrients become available and C contained in the litter is released back into

  6. Manganese Reduction-Oxidation Drives Plant Debris Decomposition

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

    Manganese Reduction-Oxidation Drives Plant Debris Decomposition Print Microbial decomposition of plant debris ("litter") is a keystone ecosystem process because it regulates nutrient availability, ecosystem productivity, and carbon (C) cycling. Historically, climate (primarily temperature and precipitation) has been thought to regulate the rate of litter decomposition, which then influences the rate at which nutrients become available and C contained in the litter is released back into

  7. Manganese Reduction-Oxidation Drives Plant Debris Decomposition

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

    Manganese Reduction-Oxidation Drives Plant Debris Decomposition Print Microbial decomposition of plant debris ("litter") is a keystone ecosystem process because it regulates nutrient availability, ecosystem productivity, and carbon (C) cycling. Historically, climate (primarily temperature and precipitation) has been thought to regulate the rate of litter decomposition, which then influences the rate at which nutrients become available and C contained in the litter is released back into

  8. Decomposition of calcium sulfate: a review of the literature...

    Office of Scientific and Technical Information (OSTI)

    Decomposition of calcium sulfate: a review of the literature. 62 refs Citation Details ... Country of Publication: United States Language: English Subject: 37 INORGANIC, ORGANIC, ...

  9. Effect of Palladium Form on Tetraphenylborate Decomposition Rate

    SciTech Connect (OSTI)

    Walker, D.D.

    1998-04-28

    Palladium catalyzes the decomposition of tetraphenylborate in alkaline solutions. Researchers postulate several decomposition mechanisms that differ in the form of the palladium catalyst. Potential forms include solid and soluble, different soluble species (such as aqueous or organic soluble), and different oxidation states (i.e., 0, II, and IV). Initial tests measured the reactivity and distribution of four Pd forms in tetraphenylborate slurries.

  10. Integrated Network Decompositions and Dynamic Programming for Graph Optimization (INDDGO)

    Energy Science and Technology Software Center (OSTI)

    2012-05-31

    The INDDGO software package offers a set of tools for finding exact solutions to graph optimization problems via tree decompositions and dynamic programming algorithms. Currently the framework offers serial and parallel (distributed memory) algorithms for finding tree decompositions and solving the maximum weighted independent set problem. The parallel dynamic programming algorithm is implemented on top of the MADNESS task-based runtime.

  11. Radiation-induced decomposition of explosives under extreme conditions

    SciTech Connect (OSTI)

    Giefers, Hubertus; Pravica, Michael; Yang, Wenge; Liermann, Peter

    2008-11-03

    We present high-pressure and high temperature studies of the synchrotron radiation-induced decomposition of powder secondary high explosives pentaerythritol tetranitrate (PETN) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) using white beam synchrotron radiation at the 16 BM-B and 16 BM-D sectors of the HP-CAT beamline at the Advanced Photon Source. The radiation-induced decomposition rate TATB showed dramatic slowing with pressure up to 26.6 GPa (the highest pressure studied), implying a positive activation volume of the activated complex. The decomposition rate of PETN varied little with pressure up to 15.7 GPa (the highest pressure studied). Diffraction line intensities were measured as a function of time using energy-dispersive methods. By measuring the decomposition rate as a function of pressure and temperature, kinetic and other constants associated with the decomposition reactions were extracted.

  12. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ), a ceramic-metal material showing a highmore electrical conductivity and ther mal stability, which is known to be most effectively used as anodes for solid ox ide fuel cells. ...

  13. Hydrogen production by the decomposition of water

    DOE Patents [OSTI]

    Hollabaugh, Charles M.; Bowman, Melvin G.

    1981-01-01

    How to produce hydrogen from water was a problem addressed by this invention. The solution employs a combined electrolytical-thermochemical sulfuric acid process. Additionally, high purity sulfuric acid can be produced in the process. Water and SO.sub.2 react in electrolyzer (12) so that hydrogen is produced at the cathode and sulfuric acid is produced at the anode. Then the sulfuric acid is reacted with a particular compound M.sub.r X.sub.s so as to form at least one water insoluble sulfate and at least one water insoluble oxide of molybdenum, tungsten, or boron. Water is removed by filtration; and the sulfate is decomposed in the presence of the oxide in sulfate decomposition zone (21), thus forming SO.sub.3 and reforming M.sub.r X.sub.s. The M.sub.r X.sub.s is recycled to sulfate formation zone (16). If desired, the SO.sub.3 can be decomposed to SO.sub.2 and O.sub.2 ; and the SO.sub.2 can be recycled to electrolyzer (12) to provide a cycle for producing hydrogen.

  14. Meson mass decomposition from lattice QCD (Journal Article) ...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Meson mass decomposition from lattice QCD Authors: Yang, Yi-Bo ; Chen, Ying ; Draper, Terrence ; Gong, Ming ; Liu, Keh-Fei ; Liu, ...

  15. Pressure Dependent Decomposition Kinetics of the Energetic Material...

    Office of Scientific and Technical Information (OSTI)

    Kinetics of the Energetic Material HMX up to 3.6 GPa The effect of pressure on the thermal decomposition rate of the energetic material HMX was studied. HMX was...

  16. Solid Double-Layered Hydroxide Catalysts for Lignin Decomposition - Energy

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

    Innovation Portal Biomass and Biofuels Biomass and Biofuels Find More Like This Return to Search Solid Double-Layered Hydroxide Catalysts for Lignin Decomposition National Renewable Energy Laboratory Contact NREL About This Technology Technology Marketing Summary Biomass-based fuel and chemical production has shown significant promise. However, costs and utilization rates of biomass have still been a challenge for large scale commercialization. Through appropriate decomposition and

  17. Urea Decomposition and SCR Performance at Low Temperature | Department of

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

    Energy Decomposition and SCR Performance at Low Temperature Urea Decomposition and SCR Performance at Low Temperature 2004 Diesel Engine Emissions Reduction (DEER) Conference Presentation: Oak Ridge National Laboratory 2004_deer_sluder.pdf (210.18 KB) More Documents & Publications Fuel-Borne Reductants for NOx Aftertreatment: Preliminary EtOH SCR Study CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR Development of Optimal Catalyst Designs and Operating

  18. Hydrogen production by the decomposition of water

    DOE Patents [OSTI]

    Hollabaugh, C.M.; Bowman, M.G.

    A process is described for the production of hydrogen from water by a sulfuric acid process employing electrolysis and thermo-chemical decomposition. The water containing SO/sub 2/ is electrolyzed to produce H/sub 2/ at the cathode and to oxidize the SO/sub 2/ to form H/sub 2/SO/sub 4/ at the anode. After the H/sub 2/ has been separated, a compound of the type M/sub r/X/sub s/ is added to produce a water insoluble sulfate of M and a water insoluble oxide of the metal in the radical X. In the compound M/sub r/X/sub s/, M is at least one metal selected from the group consisting of Ba/sup 2 +/, Ca/sup 2 +/, Sr/sup 2 +/, La/sup 2 +/, and Pb/sup 2 +/; X is at least one radical selected from the group consisting of molybdate (MoO/sub 4//sup 2 -/), tungstate (WO/sub 4//sup 2 -/), and metaborate (BO/sub 2//sup 1 -/); and r and s are either 1, 2, or 3 depending upon the valence of M and X. The precipitated mixture is filtered and heated to a temperature sufficiently high to form SO/sub 3/ gas and to reform M/sub r/X/sub s/. The SO/sub 3/ is dissolved in a small amount of H/sub 2/O to produce concentrated H/sub 2/SO/sub 4/, and the M/sub r/X/sub s/ is recycled to the process. Alternatively, the SO/sub 3/ gas can be recycled to the beginning of the process to provide a continuous process for the production of H/sub 2/ in which only water need be added in a substantial amount. (BLM)

  19. Seventh international conference on Domain decomposition methods in scientific and engineering computing

    SciTech Connect (OSTI)

    1993-12-31

    This report contains abstracts presented at the Seventh International Conference on Domain Decomposition Methods.

  20. Site-related near-infrared luminescence in MAl{sub 12}O{sub 19} (M = Ca, Sr, Ba):Fe{sup 3+} phosphors

    SciTech Connect (OSTI)

    Li, Y.J.; Ma, Y.Y.; Ye, S.; Hu, G.P.; Zhang, Q.Y.

    2014-03-01

    Graphical abstract: - Highlights: • Intense 700–850 nm NIR emissions in MAl{sub 12}O{sub 19} (M = Ca, Sr, Ba):1%Fe{sup 3+} has been obtained. • The NIR emissions can be ascribed to the octahedral Fe{sup 3+} sites. • The site symmetry of Fe{sup 3+} in CA{sub 6} and SA{sub 6} may be lower than that in BA{sub 6}. • The phosphors may be potentially applied in the high-resolution bioimaging. - Abstract: Intense and broad near-infrared (NIR) photoluminescence (PL) peaks locating at 777, 808 and 810 nm is observed for BaAl{sub 12}O{sub 19} (BA{sub 6}):1%Fe{sup 3+}, CaAl{sub 12}O{sub 19} (CA{sub 6}):1%Fe{sup 3+} and SrAl{sub 12}O{sub 19} (SA{sub 6}):1%Fe{sup 3+}, respectively. Electron paramagnetic resonance (EPR) spectra show that Fe{sup 3+} ions substitute for the different types of Al{sup 3+} sites simultaneously. Meanwhile, the luminescence of Fe{sup 3+} in MAl{sub 12}O{sub 19} (M = Ca, Sr and Ba) are ascribed to octahedral Fe{sup 3+}. In addition, the site symmetry of Fe{sup 3+} in CA{sub 6}/SA{sub 6} is lower compared with BA{sub 6}, deduced from the photoluminescence excitation (PLE), EPR and Fourier-transform infrared (FT-IR) spectra. These phosphors can be considered as good candidates for the applications in the field of high-resolution bioimaging.

  1. Thermochemical decomposition and isomerization of polysilacyclodialkynes and thermochemical and photochemical decomposition of cyclopolysilylketenes

    SciTech Connect (OSTI)

    Altman, L.B.

    1994-05-10

    Kinetic data for elimination of silylene supports formation of a ``tighter`` transition state, indicating a silacyclopropene intermediate. This extends the silacyclopropene mechanism to the cyclicdialkyne system and validates the consistency of the mechanism for silylakynes, in general. Investigation into the other possible silacyclopropene product established the instability of the product. The work with silylketenes proved that an inherent difference exists between reactivity of monosilyl-substituted ketenes and polysilyl-substituted ketenes. Although the mechanism for thermal decomposition of bis(silyl)ketenes can be modified to account for the unexpected silylene elimination products, reasons for the difference are limited to speculation. The photochemistry of silylketenes has not been previously studied, so a model system does not exist for comparison with our polysilylketene work. The photochemical experimentation suggests that the photochemistry and thermochemistry of polysilylketenes is not the same. A more extensive study of the mechanism of the systems covered in this research as well as with monosilyl-substituted systems is needed.

  2. Thermal Decomposition of IMX-104: Ingredient Interactions Govern Thermal Insensitivity

    SciTech Connect (OSTI)

    Maharrey, Sean; Wiese-Smith, Deneille; Highley, Aaron M.; Steill, Jeffrey D.; Behrens, Richard; Kay, Jeffrey J.

    2015-04-01

    This report summarizes initial studies into the chemical basis of the thermal insensitivity of INMX-104. The work follows upon similar efforts investigating this behavior for another DNAN-based insensitive explosive, IMX-101. The experiments described demonstrate a clear similarity between the ingredient interactions that were shown to lead to the thermal insensitivity observed in IMX-101 and those that are active in IMX-104 at elevated temperatures. Specifically, the onset of decomposition of RDX is shifted to a lower temperature based on the interaction of the RDX with liquid DNAN. This early onset of decomposition dissipates some stored energy that is then unavailable for a delayed, more violent release.

  3. A coke oven model including thermal decomposition kinetics of tar

    SciTech Connect (OSTI)

    Munekane, Fuminori; Yamaguchi, Yukio; Tanioka, Seiichi

    1997-12-31

    A new one-dimensional coke oven model has been developed for simulating the amount and the characteristics of by-products such as tar and gas as well as coke. This model consists of both heat transfer and chemical kinetics including thermal decomposition of coal and tar. The chemical kinetics constants are obtained by estimation based on the results of experiments conducted to investigate the thermal decomposition of both coal and tar. The calculation results using the new model are in good agreement with experimental ones.

  4. Resolving the sign ambiguity in the singular value decomposition.

    SciTech Connect (OSTI)

    Bro, Rasmus; Acar, Evrim; Kolda, Tamara Gibson

    2007-10-01

    Many modern data analysis methods involve computing a matrix singular value decomposition (SVD) or eigenvalue decomposition (EVD). Principal components analysis is the time-honored example, but more recent applications include latent semantic indexing, hypertext induced topic selection (HITS), clustering, classification, etc. Though the SVD and EVD are well-established and can be computed via state-of-the-art algorithms, it is not commonly mentioned that there is an intrinsic sign indeterminacy that can significantly impact the conclusions and interpretations drawn from their results. Here we provide a solution to the sign ambiguity problem and show how it leads to more sensible solutions.

  5. Iterative image-domain decomposition for dual-energy CT

    SciTech Connect (OSTI)

    Niu, Tianye; Dong, Xue; Petrongolo, Michael; Zhu, Lei

    2014-04-15

    Purpose: Dual energy CT (DECT) imaging plays an important role in advanced imaging applications due to its capability of material decomposition. Direct decomposition via matrix inversion suffers from significant degradation of image signal-to-noise ratios, which reduces clinical values of DECT. Existing denoising algorithms achieve suboptimal performance since they suppress image noise either before or after the decomposition and do not fully explore the noise statistical properties of the decomposition process. In this work, the authors propose an iterative image-domain decomposition method for noise suppression in DECT, using the full variance-covariance matrix of the decomposed images. Methods: The proposed algorithm is formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, the authors include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. The regularization term enforces the image smoothness by calculating the square sum of neighboring pixel value differences. To retain the boundary sharpness of the decomposed images, the authors detect the edges in the CT images before decomposition. These edge pixels have small weights in the calculation of the regularization term. Distinct from the existing denoising algorithms applied on the images before or after decomposition, the method has an iterative process for noise suppression, with decomposition performed in each iteration. The authors implement the proposed algorithm using a standard conjugate gradient algorithm. The method performance is evaluated using an evaluation phantom (Catphan600) and an anthropomorphic head phantom. The results are compared with those generated using direct matrix inversion with no noise suppression, a denoising method applied on the decomposed images, and an existing algorithm with similar formulation as the

  6. Method for improved decomposition of metal nitrate solutions

    DOE Patents [OSTI]

    Haas, P.A.; Stines, W.B.

    1981-01-21

    A method for co-conversion of aqueous solutions of one or more heavy metal nitrates is described, wherein thermal decomposition within a temperature range of about 300 to 800/sup 0/C is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

  7. Effects of oxygen and catalyst on tetraphenylborate decomposition rate

    SciTech Connect (OSTI)

    Walker, D.D.

    1999-12-15

    Previous studies indicate that palladium catalyzes rapid decomposition of alkaline tetraphenylborate slurries. Oxygen inhibits the reaction at low temperature (25 C), presumably by preventing activation of the catalyst. The present study investigated oxygen's inhibiting effectiveness at higher temperature (45 C) and catalyst concentrations.

  8. Quantitative and qualitative measures of decomposition: Is there a link?

    SciTech Connect (OSTI)

    Eaton, Robert, J.; Sanchez, Felipe, G.

    2009-03-01

    Decomposition rates of loblolly pine coarse woody debris (CWD) were determined by mass loss and wood density changes for trees that differed in source of mortality (natural, girdle-poison, and felling). Specifically, three treatments were examined: (1) control (CON): natural mortality; (2) CD: 5-fold increase in CWD compared with the CON; and (3) CS: 12-fold increase in snags compared with the CON. The additional CWD in the CD treatment plots and the additional snags in the CS plots were achieved by felling (for the CD plots) or girdling followed by herbicide injection (for the CS plots) select trees in these plots. Consequently,mortality on the CD plots is due to natural causes and felling. Likewise, mortality on the CS plots is due to natural causes and girdle-poison. In each treatment plot, mortality due to natural causes was inventoried since 1997, whereas mortality due to girdle-poison and felling were inventoried since 2001. No significant difference was detected between the rates of decomposition for the CWD on these treatment plots, indicating that source of the tree mortality did not influence rates of decomposition once the tree fell. These experimental measures of decomposition were compared with two decay classification systems (three- and five-unit classifications) to determine linkages. Changes in wood density did not correlate to any decay classification, whereas mass loss had a weak correlation with decay class. However, the large degree of variation limits the utility of decay classification systems in estimating mass loss.

  9. Limited-memory adaptive snapshot selection for proper orthogonal decomposition

    SciTech Connect (OSTI)

    Oxberry, Geoffrey M.; Kostova-Vassilevska, Tanya; Arrighi, Bill; Chand, Kyle

    2015-04-02

    Reduced order models are useful for accelerating simulations in many-query contexts, such as optimization, uncertainty quantification, and sensitivity analysis. However, offline training of reduced order models can have prohibitively expensive memory and floating-point operation costs in high-performance computing applications, where memory per core is limited. To overcome this limitation for proper orthogonal decomposition, we propose a novel adaptive selection method for snapshots in time that limits offline training costs by selecting snapshots according an error control mechanism similar to that found in adaptive time-stepping ordinary differential equation solvers. The error estimator used in this work is related to theory bounding the approximation error in time of proper orthogonal decomposition-based reduced order models, and memory usage is minimized by computing the singular value decomposition using a single-pass incremental algorithm. Results for a viscous Burgers’ test problem demonstrate convergence in the limit as the algorithm error tolerances go to zero; in this limit, the full order model is recovered to within discretization error. The resulting method can be used on supercomputers to generate proper orthogonal decomposition-based reduced order models, or as a subroutine within hyperreduction algorithms that require taking snapshots in time, or within greedy algorithms for sampling parameter space.

  10. Decomposition of Perfluorocompounds on Alumina-Based Catalyst

    SciTech Connect (OSTI)

    Kanno, Shuichi; Tamata, Shin; Kurokawa, Hideaki

    2004-03-31

    The control of the atmospheric release of PFCs (perfluorocompounds) is an important environmental problem worldwide. PFCs are powerful greenhouse gases used by the semiconductor and liquid crystal industries as etching and cleaning agents. We developed a catalyst that decomposes PFCs with only water. Al2O3 was selected from the survey of some single metal-oxide catalysts. Addition of another metal-oxide improved the decomposition ratio and durability. The Al2O3-based catalyst decomposed CF4, C2F6, C3F8, C4F8, NF3 and SF6 by more than 99% at 750 degrees Celsius. Furthermore, our catalyst retained a high decomposition ratio as demonstrated by a continuous run for about 4000 hours at 700-750 degrees Celsius. The influence of chlorine as an impurity with regard to the SF6 decomposition ratio on the catalyst was examined. SF6 was decomposed at more than 99% during 8 hours in the presence of 400 ppm chlorine. Chlorine concentration in the outlet gas was less than TLV. No chlorine compounds were found by X-ray diffraction analysis of the used catalyst. That is, the hydrogenation of chlorine did not inhibit the surface catalytic reaction for PFC. Also, CF4 was decomposed at the condition of 1.4% of high concentration. The conversion remained higher than 99% throughout during a durability test. Furthermore, we investigated a large-scale decomposition system in the paper.

  11. INDDGO: Integrated Network Decomposition & Dynamic programming for Graph Optimization

    SciTech Connect (OSTI)

    Groer, Christopher S; Sullivan, Blair D; Weerapurage, Dinesh P

    2012-10-01

    It is well-known that dynamic programming algorithms can utilize tree decompositions to provide a way to solve some \\emph{NP}-hard problems on graphs where the complexity is polynomial in the number of nodes and edges in the graph, but exponential in the width of the underlying tree decomposition. However, there has been relatively little computational work done to determine the practical utility of such dynamic programming algorithms. We have developed software to construct tree decompositions using various heuristics and have created a fast, memory-efficient dynamic programming implementation for solving maximum weighted independent set. We describe our software and the algorithms we have implemented, focusing on memory saving techniques for the dynamic programming. We compare the running time and memory usage of our implementation with other techniques for solving maximum weighted independent set, including a commercial integer programming solver and a semi-definite programming solver. Our results indicate that it is possible to solve some instances where the underlying decomposition has width much larger than suggested by the literature. For certain types of problems, our dynamic programming code runs several times faster than these other methods.

  12. Roaming radical pathways for the decomposition of alkanes.

    SciTech Connect (OSTI)

    Harding, L. B.; Klippenstein, S. J.

    2010-01-01

    CASPT2 calculations predict the existence of roaming radical pathways for the decomposition of propane, n-butane, isobutane and neopentane. The roaming radical paths lead to the formation of an alkane and an alkene instead of the expected radical products. The predicted barriers for the roaming radical paths lie {approx}1 kcal/mol below the corresponding radical asymptotes.

  13. Method for improved decomposition of metal nitrate solutions

    DOE Patents [OSTI]

    Haas, Paul A.; Stines, William B.

    1983-10-11

    A method for co-conversion of aqueous solutions of one or more heavy metal nitrates wherein thermal decomposition within a temperature range of about 300.degree. to 800.degree. C. is carried out in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal.

  14. In vivo subcellular localization of Mal de Rio Cuarto virus (MRCV) non-structural proteins in insect cells reveals their putative functions

    SciTech Connect (OSTI)

    Maroniche, Guillermo A.; Mongelli, Vanesa C.; Llauger, Gabriela; Alfonso, Victoria; Taboga, Oscar

    2012-09-01

    The in vivo subcellular localization of Mal de Rio Cuarto virus (MRCV, Fijivirus, Reoviridae) non-structural proteins fused to GFP was analyzed by confocal microscopy. P5-1 showed a cytoplasmic vesicular-like distribution that was lost upon deleting its PDZ binding TKF motif, suggesting that P5-1 interacts with cellular PDZ proteins. P5-2 located at the nucleus and its nuclear import was affected by the deletion of its basic C-termini. P7-1 and P7-2 also entered the nucleus and therefore, along with P5-2, could function as regulators of host gene expression. P6 located in the cytoplasm and in perinuclear cloud-like inclusions, was driven to P9-1 viroplasm-like structures and co-localized with P7-2, P10 and {alpha}-tubulin, suggesting its involvement in viroplasm formation and viral intracellular movement. Finally, P9-2 was N-glycosylated and located at the plasma membrane in association with filopodia-like protrusions containing actin, suggesting a possible role in virus cell-to-cell movement and spread.

  15. Domain decomposition methods for solving an image problem

    SciTech Connect (OSTI)

    Tsui, W.K.; Tong, C.S.

    1994-12-31

    The domain decomposition method is a technique to break up a problem so that ensuing sub-problems can be solved on a parallel computer. In order to improve the convergence rate of the capacitance systems, pre-conditioned conjugate gradient methods are commonly used. In the last decade, most of the efficient preconditioners are based on elliptic partial differential equations which are particularly useful for solving elliptic partial differential equations. In this paper, the authors apply the so called covering preconditioner, which is based on the information of the operator under investigation. Therefore, it is good for various kinds of applications, specifically, they shall apply the preconditioned domain decomposition method for solving an image restoration problem. The image restoration problem is to extract an original image which has been degraded by a known convolution process and additive Gaussian noise.

  16. Patched bimetallic surfaces are active catalysts for ammonia decomposition

    SciTech Connect (OSTI)

    Guo, Wei; Vlachos, Dionisios G.

    2015-10-07

    In this study, ammonia decomposition is often used as an archetypical reaction for predicting new catalytic materials and understanding the very reason of why some reactions are sensitive on material’s structure. Core–shell or surface-segregated bimetallic nanoparticles expose outstanding activity for many heterogeneously catalysed reactions but the reasons remain elusive owing to the difficulties in experimentally characterizing active sites. Here by performing multiscale simulations in ammonia decomposition on various nickel loadings on platinum (111), we show that the very high activity of core–shell structures requires patches of the guest metal to create and sustain dual active sites: nickel terraces catalyse N-H bond breaking and nickel edge sites drive atomic nitrogen association. The structure sensitivity on these active catalysts depends profoundly on reaction conditions due to kinetically competing relevant elementary reaction steps. We expose a remarkable difference in active sites between transient and steady-state studies and provide insights into optimal material design.

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

    SciTech Connect (OSTI)

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

    2011-06-23

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

  18. Optical ranked-order filtering using threshold decomposition

    DOE Patents [OSTI]

    Allebach, Jan P.; Ochoa, Ellen; Sweeney, Donald W.

    1990-01-01

    A hybrid optical/electronic system performs median filtering and related ranked-order operations using threshold decomposition to encode the image. Threshold decomposition transforms the nonlinear neighborhood ranking operation into a linear space-invariant filtering step followed by a point-to-point threshold comparison step. Spatial multiplexing allows parallel processing of all the threshold components as well as recombination by a second linear, space-invariant filtering step. An incoherent optical correlation system performs the linear filtering, using a magneto-optic spatial light modulator as the input device and a computer-generated hologram in the filter plane. Thresholding is done electronically. By adjusting the value of the threshold, the same architecture is used to perform median, minimum, and maximum filtering of images. A totally optical system is also disclosed.

  19. Optical ranked-order filtering using threshold decomposition

    DOE Patents [OSTI]

    Allebach, J.P.; Ochoa, E.; Sweeney, D.W.

    1987-10-09

    A hybrid optical/electronic system performs median filtering and related ranked-order operations using threshold decomposition to encode the image. Threshold decomposition transforms the nonlinear neighborhood ranking operation into a linear space-invariant filtering step followed by a point-to-point threshold comparison step. Spatial multiplexing allows parallel processing of all the threshold components as well as recombination by a second linear, space-invariant filtering step. An incoherent optical correlation system performs the linear filtering, using a magneto-optic spatial light modulator as the input device and a computer-generated hologram in the filter plane. Thresholding is done electronically. By adjusting the value of the threshold, the same architecture is used to perform median, minimum, and maximum filtering of images. A totally optical system is also disclosed. 3 figs.

  20. Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

    SciTech Connect (OSTI)

    Mehmood, Faisal; Greeley, Jeffrey P.; Curtiss, Larry A.

    2009-12-31

    A density functional theory study of the decomposition of methanol on subnanometer palladium clusters (primarily Pd4) is presented. Methanol dehydrogenation through C-H bond breaking to form hydroxymethyl (CH2OH) as the initial step, followed by steps involving formation of hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO), is found to be the most favorable reaction pathway. A competing dehydrogenation pathway with O-H bond breaking as the first step, followed by formation of methoxy (CH3O) and formaldehyde (CH2O), is slightly less favorable. In contrast, pathways involving C-O bond cleavage are much less energetically favorable, and no feasible pathways involving C-O bond formation to yield dimethyl ether (CH3OCH3) are found. Comparisons of the results are made with methanol decomposition products adsorbed on more extended Pd surfaces; all reaction intermediates are found to bind slightly more strongly to the clusters than to the surfaces.

  1. Thermal decomposition of silane to form hydrogenated amorphous Si film

    DOE Patents [OSTI]

    Strongin, Myron; Ghosh, Arup K.; Wiesmann, Harold J.; Rock, Edward B.; Lutz, III, Harry A.

    1980-01-01

    This invention relates to hydrogenated amorphous silicon produced by thermally decomposing silano (SiH.sub.4) or other gases comprising H and Si, at elevated temperatures of about 1700.degree.-2300.degree. C., and preferably in a vacuum of about 10.sup.-8 to 10.sup.-4 torr, to form a gaseous mixture of atomic hydrogen and atomic silicon, and depositing said gaseous mixture onto a substrate outside said source of thermal decomposition to form hydrogenated amorphous silicon.

  2. Some studies on anaerobic decomposition of leucaena leucocephala leaves

    SciTech Connect (OSTI)

    Torane, J.V.; Lokhande, C.D.; Pawar, S.H. )

    1990-01-01

    Batch type anaerobic decomposition process in leucaena leucocephala plant material (leaves) has been carried out under mesophilic conditions (below 35{degrees}C). The results of studies involving variations in pH, conductivity, temperature, and optical density of digester slurry for four weeks are reported. The gas production rate was also studied which reveals that the use of leucaena leucocephala for biogas production will be helpful.

  3. Adaptive domain decomposition methods for advection-diffusion problems

    SciTech Connect (OSTI)

    Carlenzoli, C.; Quarteroni, A.

    1995-12-31

    Domain decomposition methods can perform poorly on advection-diffusion equations if diffusion is dominated by advection. Indeed, the hyperpolic part of the equations could affect the behavior of iterative schemes among subdomains slowing down dramatically their rate of convergence. Taking into account the direction of the characteristic lines we introduce suitable adaptive algorithms which are stable with respect to the magnitude of the convective field in the equations and very effective on bear boundary value problems.

  4. RADIUS: Rapid Automated Decomposition of Images for Ubiquitous Sensing

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

    4-21456 This document is approved for public release; further dissemination unlimited Rapid Automated Decomposition of Images for Ubiquitous Sensing RADIUS: RADIUS: State-of-the-art pixel and color based methods do not exploit the multiscale spatial and structural cues in images for effective and efficient analysis * Miss large or small features * Limited scalability to large images Increased analyst performance * Real-time automated image analysis * Direct analyst to selected features in the

  5. Volume Decomposition and Feature Recognition for Hexahedral Mesh Generation

    SciTech Connect (OSTI)

    GADH,RAJIT; LU,YONG; TAUTGES,TIMOTHY J.

    1999-09-27

    Considerable progress has been made on automatic hexahedral mesh generation in recent years. Several automatic meshing algorithms have proven to be very reliable on certain classes of geometry. While it is always worth pursuing general algorithms viable on more general geometry, a combination of the well-established algorithms is ready to take on classes of complicated geometry. By partitioning the entire geometry into meshable pieces matched with appropriate meshing algorithm the original geometry becomes meshable and may achieve better mesh quality. Each meshable portion is recognized as a meshing feature. This paper, which is a part of the feature based meshing methodology, presents the work on shape recognition and volume decomposition to automatically decompose a CAD model into meshable volumes. There are four phases in this approach: (1) Feature Determination to extinct decomposition features, (2) Cutting Surfaces Generation to form the ''tailored'' cutting surfaces, (3) Body Decomposition to get the imprinted volumes; and (4) Meshing Algorithm Assignment to match volumes decomposed with appropriate meshing algorithms. The feature determination procedure is based on the CLoop feature recognition algorithm that is extended to be more general. Results are demonstrated over several parts with complicated topology and geometry.

  6. Evaluation of microporous carbon filters as catalysts for ozone decomposition

    SciTech Connect (OSTI)

    Whinnery, L.; Coutts, D.; Shen, C.; Adams, R. [Sandia National Labs., Livermore, CA (United States); Quintana, C.; Showalter, S. [Sandia National Labs., Albuquerque, NM (United States)

    1994-12-31

    Ozone is produced in small quantities in photocopiers and laser printers in the workplace and large quantities in industrial waste water treatment facilities. Carbon filters are commonly used to decompose this unwanted ozone. The three most important factors in producing a filter for this purpose are flow properties, efficiency, and cost. Most ozone decomposition applications require very low back-pressure at modest flow rates. The tradeoff between the number of pores and the size of the pores will be discussed. Typical unfiltered emissions in the workplace are approximately 1 ppm. The maximum permissible exposure limit, PEL, for worker exposure to ozone is 0.1 ppm over 8 hours. Several methods have been examined to increase the efficiency of ozone decomposition. Carbon surfaces were modified with catalysts, the surface activated, and the surface area was increased, in attempts to decompose ozone more effectively. Methods to reduce both the processing and raw material costs were investigated. Several sources of microporous carbon were investigated as ozone decomposition catalysts. Cheaper processing routes including macropore templating, faster drying and extracting methods were also studied.

  7. Roaming radical kinetics in the decomposition of acetaldehyde.

    SciTech Connect (OSTI)

    Harding, L. B.; Georgievskii, Y.; Klippenstein, S. J.; Chemical Sciences and Engineering Division

    2010-01-01

    A novel theoretical framework for predicting the branching between roaming and bond fission channels in molecular dissociations is described and applied to the decomposition of acetaldehyde. This reduced dimensional trajectory (RDT) approach, which is motivated by the long-range nature of the roaming, bond fission, and abstraction dynamical bottlenecks, involves the propagation of rigid-body trajectories on an analytic potential energy surface. The analytic potential is obtained from fits to large-scale multireference ab initio electronic structure calculations. The final potential includes one-dimensional corrections from higher-level electronic structure calculations and for the effect of conserved mode variations along both the addition and abstraction paths. The corrections along the abstraction path play a significant role in the predicted branching. Master equation simulations are used to transform the microcanonical branching ratios obtained from the RDT simulations to the temperature- and pressure-dependent branching ratios observed in thermal decomposition experiments. For completeness, a transition-state theory treatment of the contributions of the tight transition states for the molecular channels is included in the theoretical analyses. The theoretically predicted branching between molecules and radicals in the thermal decomposition of acetaldehyde is in reasonable agreement with the corresponding shock tube measurement described in the companion paper. The prediction for the ratio of the tight to roaming contributions to the molecular channel also agrees well with results extracted from recent experimental and experimental/theoretical photodissociation studies.

  8. Incremental k-core decomposition: Algorithms and evaluation

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

    Sariyuce, Ahmet Erdem; Gedik, Bugra; Jacques-SIlva, Gabriela; Wu, Kun -Lung; Catalyurek, Umit V.

    2016-02-01

    A k-core of a graph is a maximal connected subgraph in which every vertex is connected to at least k vertices in the subgraph. k-core decomposition is often used in large-scale network analysis, such as community detection, protein function prediction, visualization, and solving NP-hard problems on real networks efficiently, like maximal clique finding. In many real-world applications, networks change over time. As a result, it is essential to develop efficient incremental algorithms for dynamic graph data. In this paper, we propose a suite of incremental k-core decomposition algorithms for dynamic graph data. These algorithms locate a small subgraph that ismore » guaranteed to contain the list of vertices whose maximum k-core values have changed and efficiently process this subgraph to update the k-core decomposition. We present incremental algorithms for both insertion and deletion operations, and propose auxiliary vertex state maintenance techniques that can further accelerate these operations. Our results show a significant reduction in runtime compared to non-incremental alternatives. We illustrate the efficiency of our algorithms on different types of real and synthetic graphs, at varying scales. Furthermore, for a graph of 16 million vertices, we observe relative throughputs reaching a million times, relative to the non-incremental algorithms.« less

  9. Development of a Novel Catalyst for No Decomposition

    SciTech Connect (OSTI)

    Ates Akyurtlu; Jale Akyurtlu

    2007-06-22

    Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N{sub 2} will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation leads one to believe that the Pt/SnO{sub 2} catalysts may have a potential as NO decomposition catalysts in the presence of oxygen. This prediction is also supported by some preliminary data obtained for NO decomposition on a Pt/SnO{sub 2} catalyst in the PI's laboratory. The main objective of the research that is being undertaken is the evaluation of the Pt/SnO{sub 2} catalysts for the decomposition of NO in simulated power plant stack gases with particular attention to the resistance to deactivation by O{sub 2}, H{sub 2}O, and elevated temperatures. Temperature programmed desorption (TPD) and temperature programmed reaction (TPRx) studies on Pt/SnO{sub 2} catalysts having

  10. Development Of A Novel Catalyst For No Decomposition

    SciTech Connect (OSTI)

    Ates Akyurtlu; Jale F. Akyurtlu

    2006-09-14

    Air pollution arising from the emission of nitrogen oxides as a result of combustion taking place in boilers, furnaces and engines, has increasingly been recognized as a problem. New methods to remove NO{sub x} emissions significantly and economically must be developed. The current technology for post-combustion removal of NO is the selective catalytic reduction (SCR) of NO by ammonia or possibly by a hydrocarbon such as methane. The catalytic decomposition of NO to give N2 will be preferable to the SCR process because it will eliminate the costs and operating problems associated with the use of an external reducing species. The most promising decomposition catalysts are transition metal (especially copper)-exchanged zeolites, perovskites, and noble metals supported on metal oxides such as alumina, silica, and ceria. The main shortcoming of the noble metal reducible oxide (NMRO) catalysts is that they are prone to deactivation by oxygen. It has been reported that catalysts containing tin oxide show oxygen adsorption behavior that may involve hydroxyl groups attached to the tin oxide. This is different than that observed with other noble metal-metal oxide combinations, which have the oxygen adsorbing on the noble metal and subsequently spilling over to the metal oxide. This observation leads one to believe that the Pt/SnO{sub 2} catalysts may have a potential as NO decomposition catalysts in the presence of oxygen. This prediction is also supported by some preliminary data obtained for NO decomposition on a Pt/SnO2 catalyst in the PI's laboratory. The main objective of the research that is being undertaken is the evaluation of the Pt/SnO2 catalysts for the decomposition of NO in simulated power plant stack gases with particular attention to the resistance to deactivation by O{sub 2}, CO{sub 2}, and elevated temperatures. Temperature programmed desorption (TPD) and temperature programmed reaction (TPRx) studies on Pt/SnO2 catalysts having different noble metal

  11. Geochemical drivers of organic matter decomposition in Arctic tundra soils

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

    Herndon, Elizabeth M.; Yang, Ziming; Graham, David E.; Wullschleger, Stan D.; Gu, Baohua; Liang, Liyuan; Bargar, John; Janot, Noemie; Regier, Tom Z.

    2015-12-07

    Climate change is warming tundra ecosystems in the Arctic, resulting in the decomposition of previously-frozen soil organic matter (SOM) and release of carbon (C) to the atmosphere; however, the processes that control SOM decomposition and C emissions remain highly uncertain. In this study, we evaluate geochemical factors that influence anaerobic production of carbon dioxide (CO2) and methane (CH4) in the active layers of four ice-wedge polygons. Surface and soil pore waters were collected during the annual thaw season over a two-year period in an area containing waterlogged, low-centered polygons and well-drained, high-centered polygons. We report spatial and seasonal patterns ofmore » dissolved gases in relation to the geochemical properties of Fe and organic C as determined using spectroscopic and chromatographic techniques. Iron was present as Fe(II) in soil solution near the permafrost boundary but enriched as Fe(III) in the middle of the active layer, similar to dissolved aromatic-C and organic acids. Dissolved CH4 increased relative to dissolved CO2 with depth and varied with soil moisture in the middle of the active layer in patterns that were positively correlated with the proportion of dissolved Fe(III) in transitional and low-centered polygon soils but negatively correlated in the drier flat- and high-centered polygons. These results suggest that microbial-mediated Fe oxidation and reduction influence respiration/fermentation of SOM and production of substrates (e.g., low-molecular-weight organic acids) for methanogenesis. As a result, we infer that geochemical differences induced by water saturation dictate microbial products of SOM decomposition, and Fe geochemistry is an important factor regulating methanogenesis in anoxic tundra soils.« less

  12. Geochemical drivers of organic matter decomposition in Arctic tundra soils

    SciTech Connect (OSTI)

    Herndon, Elizabeth M.; Yang, Ziming; Graham, David E.; Wullschleger, Stan D.; Gu, Baohua; Liang, Liyuan; Bargar, John; Janot, Noemie; Regier, Tom Z.

    2015-12-07

    Climate change is warming tundra ecosystems in the Arctic, resulting in the decomposition of previously-frozen soil organic matter (SOM) and release of carbon (C) to the atmosphere; however, the processes that control SOM decomposition and C emissions remain highly uncertain. In this study, we evaluate geochemical factors that influence anaerobic production of carbon dioxide (CO2) and methane (CH4) in the active layers of four ice-wedge polygons. Surface and soil pore waters were collected during the annual thaw season over a two-year period in an area containing waterlogged, low-centered polygons and well-drained, high-centered polygons. We report spatial and seasonal patterns of dissolved gases in relation to the geochemical properties of Fe and organic C as determined using spectroscopic and chromatographic techniques. Iron was present as Fe(II) in soil solution near the permafrost boundary but enriched as Fe(III) in the middle of the active layer, similar to dissolved aromatic-C and organic acids. Dissolved CH4 increased relative to dissolved CO2 with depth and varied with soil moisture in the middle of the active layer in patterns that were positively correlated with the proportion of dissolved Fe(III) in transitional and low-centered polygon soils but negatively correlated in the drier flat- and high-centered polygons. These results suggest that microbial-mediated Fe oxidation and reduction influence respiration/fermentation of SOM and production of substrates (e.g., low-molecular-weight organic acids) for methanogenesis. As a result, we infer that geochemical differences induced by water saturation dictate microbial products of SOM decomposition, and Fe geochemistry is an important factor regulating methanogenesis in anoxic tundra soils.

  13. Decomposition of silane on tungsten or other materials

    DOE Patents [OSTI]

    Wiesmann, H.J.

    This invention relates to hydrogenated amorphous silicon produced by thermally decomposing silane (SiH/sub 4/) or other gases comprising H and Si, from a W or foil heated to a temperature of about 1400 to 1600/sup 0/C, in a vacuum of about 10-/sup 6/ to 10-/sup 4/ torr. A gaseous mixture is formed of atomic hydrogen and atomic silicon. The gaseous mixture is deposited onto a substrate independent of and outside the source of thermal decomposition. Hydrogenated amorphous silicon is formed. The presence of an ammonia atmosphere in the vacuum chamber enhances the photoconductivity of the hydrogenated amorphous silicon film.

  14. Signal evaluations using singular value decomposition for Thomson scattering diagnostics

    SciTech Connect (OSTI)

    Tojo, H., E-mail: tojo.hiroshi@jaea.go.jp; Yatsuka, E.; Hatae, T.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan); Yamada, I.; Yasuhara, R.; Funaba, H.; Hayashi, H. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2014-11-15

    This paper provides a novel method for evaluating signal intensities in incoherent Thomson scattering diagnostics. A double-pass Thomson scattering system, where a laser passes through the plasma twice, generates two scattering pulses from the plasma. Evaluations of the signal intensities in the spectrometer are sometimes difficult due to noise and stray light. We apply the singular value decomposition method to Thomson scattering data with strong noise components. Results show that the average accuracy of the measured electron temperature (T{sub e}) is superior to that of temperature obtained using a low-pass filter (<20 MHz) or without any filters.

  15. Active eutectoid decomposition in Zr-3 wt.% Fe

    SciTech Connect (OSTI)

    Kumar, L.; Ramanujan, R.V.; Tewari, R.; Mukhopadhyay, P.; Banerjee, S.

    1999-02-19

    In the work reported here, the microstructural features associated with the active eutectoid decomposition of a near eutectoid alloy (Zr-3 wt.%Fe) on {beta} quenching were examined. The effects of aging after {beta} quenching, and of furnace cooling from the {beta} phase field, on the microstructure of the alloy were also studied. The microstructural characterization was carried out using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM). The room temperature mechanical properties corresponding to some of the microstructures were evaluated by mechanical testing.

  16. Patched bimetallic surfaces are active catalysts for ammonia decomposition

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

    Guo, Wei; Vlachos, Dionisios G.

    2015-10-07

    In this study, ammonia decomposition is often used as an archetypical reaction for predicting new catalytic materials and understanding the very reason of why some reactions are sensitive on material’s structure. Core–shell or surface-segregated bimetallic nanoparticles expose outstanding activity for many heterogeneously catalysed reactions but the reasons remain elusive owing to the difficulties in experimentally characterizing active sites. Here by performing multiscale simulations in ammonia decomposition on various nickel loadings on platinum (111), we show that the very high activity of core–shell structures requires patches of the guest metal to create and sustain dual active sites: nickel terraces catalyse N-Hmore » bond breaking and nickel edge sites drive atomic nitrogen association. The structure sensitivity on these active catalysts depends profoundly on reaction conditions due to kinetically competing relevant elementary reaction steps. We expose a remarkable difference in active sites between transient and steady-state studies and provide insights into optimal material design.« less

  17. Lead Sequestration and Species Redistribution During Soil Organic Matter Decomposition

    SciTech Connect (OSTI)

    Schroth,A.; Bostick, B.; Kaste, J.; Friedland, A.

    2008-01-01

    The turnover of soil organic matter (SOM) maintains a dynamic chemical environment in the forest floor that can impact metal speciation on relatively short timescales. Here we measure the speciation of Pb in controlled and natural organic (O) soil horizons to quantify changes in metal partitioning during SOM decomposition in different forest litters. We provide a link between the sequestration of pollutant Pb in O-horizons, estimated by forest floor Pb inventories, and speciation using synchrotron-based X-ray fluorescence and X-ray absorption spectroscopy. When Pb was introduced to fresh forest Oi samples, it adsorbed primarily to SOM surfaces, but as decomposition progressed over two years in controlled experiments, up to 60% of the Pb was redistributed to pedogenic birnessite and ferrihydrite surfaces. In addition, a significant fraction of pollutant Pb in natural soil profiles was associated with similar mineral phases ({approx}20-35%) and SOM ({approx}65-80%). Conifer forests have at least 2-fold higher Pb burdens in the forest floor relative to deciduous forests due to more efficient atmospheric scavenging and slower organic matter turnover. We demonstrate that pedogenic minerals play an important role in surface soil Pb sequestration, particularly in deciduous forests, and should be considered in any assessment of pollutant Pb mobility.

  18. Cho decomposition of electrically charged one-half monopole

    SciTech Connect (OSTI)

    Ng, Ban-Loong; Teh, Rosy; Wong, Khai-Ming

    2014-03-05

    Recently we have carried out some work on the Cho decomposition of the electrically neutral, finite energy one-half monopole solution of the SU(2) Yang-Mills-Higgs field theory. In this paper, we performed the decomposition of the electrically charged solution using the same numerical procedure. The gauge potential of the one-half dyon solution is decomposed into Abelian and non-Abelian components. The semi-infinite string singularity in the gauge potential is a contribution of the Higgs field and hence topological in nature. The string singularity cannot be cancelled by the non-Abelian components of the gauge potential. However, the string singularity is integrable and the energy of the solution is finite. By decomposing the magnetic fields and covariant derivatives of the Higgs field into three isospin space directions, we are able to provide conclusive evidence that the constructed one-half dyon is certainly a non-BPS solution even in the limit of vanishing Higgs self-coupling constant and electric charge. Furthermore, we found that the time component of gauge function is parallel to the Higgs field in isospace only at large distances, elsewhere they are non-parallel.

  19. Density functional studies of methanol decomposition on subnanometer Pd clusters.

    SciTech Connect (OSTI)

    Mehmood, F.; Greeley, J.; Curtiss, L. A.

    2009-12-31

    A density functional theory study of the decomposition of methanol on subnanometer palladium clusters (primarily Pd{sub 4}) is presented. Methanol dehydrogenation through C-H bond breaking to form hydroxymethyl (CH{sub 2}OH) as the initial step, followed by steps involving formation of hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO), is found to be the most favorable reaction pathway. A competing dehydrogenation pathway with O-H bond breaking as the first step, followed by formation of methoxy (CH{sub 3}O) and formaldehyde (CH{sub 2}O), is slightly less favorable. In contrast, pathways involving C-O bond cleavage are much less energetically favorable, and no feasible pathways involving C-O bond formation to yield dimethyl ether (CH{sub 3}OCH{sub 3}) are found. Comparisons of the results are made with methanol decomposition products adsorbed on more extended Pd surfaces; all reaction intermediates are found to bind slightly more strongly to the clusters than to the surfaces.

  20. Object detection with a multistatic array using singular value decomposition

    DOE Patents [OSTI]

    Hallquist, Aaron T.; Chambers, David H.

    2014-07-01

    A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across a surface and that travels down the surface. The detection system converts the return signals from a time domain to a frequency domain, resulting in frequency return signals. The detection system then performs a singular value decomposition for each frequency to identify singular values for each frequency. The detection system then detects the presence of a subsurface object based on a comparison of the identified singular values to expected singular values when no subsurface object is present.

  1. Hydroxylamine Nitrate Decomposition under Non-radiological Conditions

    SciTech Connect (OSTI)

    McFarlane, Joanna; Delmau, Laetitia Helene; DePaoli, David W.; Mattus, Catherine H.; Phelps, Clarice E.; Roach, Benjamin D.

    2015-07-01

    Hydroxylamine nitrate (HAN) is used to reduce Pu(IV) to Pu(III) in the separation of plutonium from uranium. HAN becomes unstable under certain conditions and has been known to explode, causing injury to humans including death. Hence, it is necessary to deactivate HAN once the reduction of plutonium is finished. This report reviews what is known about the chemistry of HAN and various methods to achieve a safe decomposition. However, there are areas where more information is needed to make a decision about the handling of HAN in reprocessing of nuclear fuel. Experiments have demonstrated a number of non-radiolytic ways to safely decompose HAN, including heating in HNO3, photolytic oxidation in the presence of H2O2, and the addition of a metal such as Fe(III) that will oxidize the HAN.

  2. Parallel Algorithms for Graph Optimization using Tree Decompositions

    SciTech Connect (OSTI)

    Sullivan, Blair D; Weerapurage, Dinesh P; Groer, Christopher S

    2012-06-01

    Although many $\\cal{NP}$-hard graph optimization problems can be solved in polynomial time on graphs of bounded tree-width, the adoption of these techniques into mainstream scientific computation has been limited due to the high memory requirements of the necessary dynamic programming tables and excessive runtimes of sequential implementations. This work addresses both challenges by proposing a set of new parallel algorithms for all steps of a tree decomposition-based approach to solve the maximum weighted independent set problem. A hybrid OpenMP/MPI implementation includes a highly scalable parallel dynamic programming algorithm leveraging the MADNESS task-based runtime, and computational results demonstrate scaling. This work enables a significant expansion of the scale of graphs on which exact solutions to maximum weighted independent set can be obtained, and forms a framework for solving additional graph optimization problems with similar techniques.

  3. Kinetics and mechanism of the thermal decomposition of dimethylzinc

    SciTech Connect (OSTI)

    Sokolovskii, A.E.; Baev, A.K.

    1985-05-01

    This paper studies the thermodecomposition of dimethylzinc in a vacuum in the temperature range 554.9-611.0 K and the concentration range 0.0027-0.0188 mole/liter. The investigations were conducted by the static method with a membrane wall manometer, an essential advantage of which is the possibility of the determination of the pressure in the reaction chamber with the complete absence of contact of the dimethylzinc with air and mercury. The results of the chromatographic study of the composition of the gas phase are presented. In the range of initial concentrations the content of the main decomposition products (methane, ethane, propane) scarcely changes, whereas at a concentration of 0.0027 mole/liter the yield of propane decreases somewhat.

  4. Palladium catalysts synthesized by atomic layer deposition for methanol decomposition.

    SciTech Connect (OSTI)

    Elam, J. W.; Feng, H.; Stair, P. C.; Libera, J. A.; Setthapun, W.; Northwestern Univ.

    2010-05-25

    Atomic layer deposition (ALD) palladium films were deposited at 200 C on various ALD metal oxide surfaces using sequential exposures to Pd(II) hexafluoroacetylacetonate (Pd(hfac)2) and formalin. In situ quartz crystal microbalance measurements as well as ex situ measurements performed on planar substrates revealed that the Pd growth begins with a relatively slow nucleation process and accelerates once an adequate amount of Pd has deposited on the surface. Furthermore, the Pd nucleation is faster on ALD ZnO surfaces compared to ALD Al2O3 surfaces. ALD was utilized to synthesize highly dispersed, uniform Pd nanoparticles (1 to 2 nm in diameter) on ALD ZnO and Al2O3 coated mesoporous silica gel, and the catalytic performances of these samples were compared in the methanol decomposition reaction. The ALD Pd-Al2O3 showed high activity and hydrogen selectivity at relatively low temperatures while the ALD Pd-ZnO showed very low activity as well as quick deactivation. In situ extended X-ray absorption fine structure (EXAFS) measurement revealed that the Pd supported on ZnO 'dissolves' into the substrate during the methanol decomposition reaction which accounts for the gradual disappearance of its catalytic activity. By applying one cycle of ALD Al2O3 on top of the Pd-ZnO catalyst, the activity was enhanced and the catalyst deactivation was mitigated. This Al2O3 overcoating method stabilizes the Pd-ZnO and effectively prevents the dissolution of Pd into the ZnO substrate.

  5. Breast tissue decomposition with spectral distortion correction: A postmortem study

    SciTech Connect (OSTI)

    Ding, Huanjun; Zhao, Bo; Baturin, Pavlo; Behroozi, Farnaz; Molloi, Sabee

    2014-10-15

    Purpose: To investigate the feasibility of an accurate measurement of water, lipid, and protein composition of breast tissue using a photon-counting spectral computed tomography (CT) with spectral distortion corrections. Methods: Thirty-eight postmortem breasts were imaged with a cadmium-zinc-telluride-based photon-counting spectral CT system at 100 kV. The energy-resolving capability of the photon-counting detector was used to separate photons into low and high energy bins with a splitting energy of 42 keV. The estimated mean glandular dose for each breast ranged from 1.8 to 2.2 mGy. Two spectral distortion correction techniques were implemented, respectively, on the raw images to correct the nonlinear detector response due to pulse pileup and charge-sharing artifacts. Dual energy decomposition was then used to characterize each breast in terms of water, lipid, and protein content. In the meantime, the breasts were chemically decomposed into their respective water, lipid, and protein components to provide a gold standard for comparison with dual energy decomposition results. Results: The accuracy of the tissue compositional measurement with spectral CT was determined by comparing to the reference standard from chemical analysis. The averaged root-mean-square error in percentage composition was reduced from 15.5% to 2.8% after spectral distortion corrections. Conclusions: The results indicate that spectral CT can be used to quantify the water, lipid, and protein content in breast tissue. The accuracy of the compositional analysis depends on the applied spectral distortion correction technique.

  6. Decreases in Soil Moisture and Organic Matter Quality Suppress Microbial Decomposition Following a Boreal Forest Fire

    SciTech Connect (OSTI)

    Holden, Sandra R.; Berhe, Asmeret A.; Treseder, Kathleen K.

    2015-08-01

    Climate warming is projected to increase the frequency and severity of wildfires in boreal forests, and increased wildfire activity may alter the large soil carbon (C) stocks in boreal forests. Changes in boreal soil C stocks that result from increased wildfire activity will be regulated in part by the response of microbial decomposition to fire, but post-fire changes in microbial decomposition are poorly understood. Here, we investigate the response of microbial decomposition to a boreal forest fire in interior Alaska and test the mechanisms that control post-fire changes in microbial decomposition. We used a reciprocal transplant between a recently burned boreal forest stand and a late successional boreal forest stand to test how post-fire changes in abiotic conditions, soil organic matter (SOM) composition, and soil microbial communities influence microbial decomposition. We found that SOM decomposing at the burned site lost 30.9% less mass over two years than SOM decomposing at the unburned site, indicating that post-fire changes in abiotic conditions suppress microbial decomposition. Our results suggest that moisture availability is one abiotic factor that constrains microbial decomposition in recently burned forests. In addition, we observed that burned SOM decomposed more slowly than unburned SOM, but the exact nature of SOM changes in the recently burned stand are unclear. Finally, we found no evidence that post-fire changes in soil microbial community composition significantly affect decomposition. Taken together, our study has demonstrated that boreal forest fires can suppress microbial decomposition due to post-fire changes in abiotic factors and the composition of SOM. Models that predict the consequences of increased wildfires for C storage in boreal forests may increase their predictive power by incorporating the observed negative response of microbial decomposition to boreal wildfires.

  7. Empirical and physics based mathematical models of uranium hydride decomposition kinetics with quantified uncertainties.

    SciTech Connect (OSTI)

    Salloum, Maher N.; Gharagozloo, Patricia E.

    2013-10-01

    Metal particle beds have recently become a major technique for hydrogen storage. In order to extract hydrogen from such beds, it is crucial to understand the decomposition kinetics of the metal hydride. We are interested in obtaining a a better understanding of the uranium hydride (UH3) decomposition kinetics. We first developed an empirical model by fitting data compiled from different experimental studies in the literature and quantified the uncertainty resulting from the scattered data. We found that the decomposition time range predicted by the obtained kinetics was in a good agreement with published experimental results. Secondly, we developed a physics based mathematical model to simulate the rate of hydrogen diffusion in a hydride particle during the decomposition. We used this model to simulate the decomposition of the particles for temperatures ranging from 300K to 1000K while propagating parametric uncertainty and evaluated the kinetics from the results. We compared the kinetics parameters derived from the empirical and physics based models and found that the uncertainty in the kinetics predicted by the physics based model covers the scattered experimental data. Finally, we used the physics-based kinetics parameters to simulate the effects of boundary resistances and powder morphological changes during decomposition in a continuum level model. We found that the species change within the bed occurring during the decomposition accelerates the hydrogen flow by increasing the bed permeability, while the pressure buildup and the thermal barrier forming at the wall significantly impede the hydrogen extraction.

  8. Thermal decomposition of CF{sub 2}HCl

    SciTech Connect (OSTI)

    Su, M.C.; Kumaran, S.S.; Lim, K.P.; Michael, J.V.; Wagner, A.F.; Dixon, D.A.; Kiefer, J.H.; DiFelice, J.

    1996-09-26

    The development of a multipass optical absorption (MPA) technique for detecting CF{sub 2} radicals behind reflected shock waves and its application for studying the thermal dissociation of CF{sub 2}HCl in Kr are reported. The effective absorption cross section is 2.86x10{sup -18} cm{sup 2} at 249.8 nm. In the CF{sub 2}HCl experiments, the yield was measured to be 1.01{+-}0.06, confirming that the thermal decomposition pathway is molecular HCl elimination; i.e., CF{sub 2}HCl (+ M) {yields} CF{sub 2} + HCl (+ M). Above 1900 K, C-Cl bond fission was measured to be <1%. Rate constants for the title reaction were measured. Also, rate constants were measured and the overall enthalpy change was determined. Over 1047 <= T <= 1731 K and 113 <= P <= 589 Torr, both the magnitude and the T dependence of the measured rate constants from the two techniques are in good agreement. 43 refs., 8 figs., 3 tabs.

  9. Asymmetric modes decomposition in an overmoded relativistic backward wave oscillator

    SciTech Connect (OSTI)

    Zhang, Dian; Zhang, Jun Zhong, Huihuang; Jin, Zhenxing; Ju, Jinchuan

    2014-09-15

    Most of the investigated overmoded relativistic backward wave oscillators (RBWOs) are azimuthally symmetric; thus, they are designed through two dimensional (2-D) particle-in-cell (PIC) simulations. However, 2-D PIC simulations cannot reveal the effect of asymmetric modes on beam-wave interaction. In order to investigate whether asymmetric mode competition needs to be considered in the design of overmoded RBWOs, a numerical method of determining the composition of both symmetric and asymmetric modes in three dimensional (3-D) PIC simulations is introduced in this paper. The 2-D and 3-D PIC simulation results of an X-band overmoded RBWO are analyzed. Our analysis indicates that the 2-D and 3-D PIC simulation results of our device are quite different due to asymmetric mode competition. In fact, asymmetric surface waves, especially EH{sub 11} mode, can lead to serious mode competition when electron beam propagates near the surface of slow wave structures (SWSs). Therefore, additional method of suppressing asymmetric mode competition, such as adjusting the reflections at both ends of SWSs to decrease the Q-factor of asymmetric modes, needs to be utilized in the design of overmoded RBWOs. Besides, 3-D PIC simulation and modes decomposition are essential for designing overmoded RBWOs.

  10. Theoretical rate coefficients for allyl + HO2 and allyloxy decomposition

    SciTech Connect (OSTI)

    Goldsmith, C. F.; Klippenstein, S. J.; Green, W. H.

    2011-01-01

    The kinetics of the allyl + HO{sub 2} bimolecular reaction, the thermal decomposition of C{sub 3}H{sub 5}OOH, and the unimolecular reactions of C{sub 3}H{sub 5}O are studied theoretically. High-level ab initio calculations of the C{sub 3}H{sub 5}OOH and C{sub 3}H{sub 5}O potential energy surfaces are coupled with RRKM master equation methods to compute the temperature- and pressure-dependence of the rate coefficients. Variable reaction coordinate transition state theory is used to characterize the barrierless transition states for the allyl + HO{sub 2} and C{sub 3}H{sub 5}O + OH reactions. The predicted rate coefficients for allyl + HO{sub 2} ? C{sub 3}H{sub 5}OOH ? products are in good agreement with experimental values. The calculations for allyl + HO{sub 2} ? C{sub 3}H{sub 6} + O{sub 2} underpredict the observed rate. The new rate coefficients suggest that the reaction of allyl + HO{sub 2} will promote chain-branching significantly more than previous models suggest.

  11. Normal form decomposition for Gaussian-to-Gaussian superoperators

    SciTech Connect (OSTI)

    De Palma, Giacomo; Mari, Andrea; Giovannetti, Vittorio; Holevo, Alexander S.

    2015-05-15

    In this paper, we explore the set of linear maps sending the set of quantum Gaussian states into itself. These maps are in general not positive, a feature which can be exploited as a test to check whether a given quantum state belongs to the convex hull of Gaussian states (if one of the considered maps sends it into a non-positive operator, the above state is certified not to belong to the set). Generalizing a result known to be valid under the assumption of complete positivity, we provide a characterization of these Gaussian-to-Gaussian (not necessarily positive) superoperators in terms of their action on the characteristic function of the inputs. For the special case of one-mode mappings, we also show that any Gaussian-to-Gaussian superoperator can be expressed as a concatenation of a phase-space dilatation, followed by the action of a completely positive Gaussian channel, possibly composed with a transposition. While a similar decomposition is shown to fail in the multi-mode scenario, we prove that it still holds at least under the further hypothesis of homogeneous action on the covariance matrix.

  12. Radiation-Induced Decomposition of PETN and TATB under Extreme Conditions

    SciTech Connect (OSTI)

    Giefers, Hubertus; Pravica, Michael

    2008-11-03

    We conducted a series of experiments investigating decomposition of secondary explosives PETN and TATB at varying static pressures and temperatures using synchrotron radiation. As seen in our earlier work, the decomposition rate of TATB at ambient temperature slows systematically with increasing pressure up to at least 26 GPa but varies little with pressure in PETN at ambient temperature up to 15.7 GPa, yielding important information pertaining to the activation complex volume in both cases. We also investigated the radiation-induced decomposition rate as a function of temperature at ambient pressure and 26 GPa for TATB up to 403 K, observing that the decomposition rate increases with increasing temperature as expected. The activation energy for the TATB reaction at ambient temperature was experimentally determined to be 16 {+-} 3 kJ/mol.

  13. Examination of phase transformations and decomposition chemistry in thermally aged thin-film explosives

    SciTech Connect (OSTI)

    Erickson, K.L.; Trott, W.M.; Renlund, A.M.

    1993-09-01

    To develop predictive models for the response of weapon systems to abnormal thermal environments, such as cookoff, an improved understanding of temperature-dependent thermophysical phenomena (such as phase transformations) and decomposition chemistry in totally confined explosive samples is needed. It is particularly important to examine the effects of maintaining-intimate contact between the decomposition products and the remaining condensed-phase explosive during slow reaction at elevated temperatures since confinement of the decomposition products may significantly affect thermophysical phenomena and decomposition reaction rates. The purpose of this work has been to examine experimentally the effects on condensed-phase chemistry which result when decomposition products remain in intimate contact with the reacting explosive during isothermal aging experiments at temperatures below those of the DTA exotherm for the explosive. To provide confinement, minimize vapor space, and permit condensed-phase chemical analysis, experiments were done using thin-film samples of the explosive, which were pressed and sealed between two infrared-transmitting windows, so that condensed-phase chemistry could be monitored using infrared spectroscopy. Experiments were done with NC, HMX, HMX-NC composite, and RDX samples. Results from the experiments with NC showed that for some decomposition mechanisms, the reaction rates for confined samples compared favorably with published reaction rates from unconfined samples. However, the results also demonstrated that for other mechanisms, the reaction rates were significantly affected by confinement of the decomposition products. The experiments with HMX and RDX indicated that some decomposition occurred at temperatures well below the temperatures of the respective DTA exotherms, and the experiments with HMX-NC composite samples showed some interaction between NC and HMX at temperatures as low as 150{degrees}C.

  14. TU-F-18A-02: Iterative Image-Domain Decomposition for Dual-Energy CT

    SciTech Connect (OSTI)

    Niu, T; Dong, X; Petrongolo, M; Zhu, L

    2014-06-15

    Purpose: Dual energy CT (DECT) imaging plays an important role in advanced imaging applications due to its material decomposition capability. Direct decomposition via matrix inversion suffers from significant degradation of image signal-to-noise ratios, which reduces clinical value. Existing de-noising algorithms achieve suboptimal performance since they suppress image noise either before or after the decomposition and do not fully explore the noise statistical properties of the decomposition process. We propose an iterative image-domain decomposition method for noise suppression in DECT, using the full variance-covariance matrix of the decomposed images. Methods: The proposed algorithm is formulated in the form of least-square estimation with smoothness regularization. It includes the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. Performance is evaluated using an evaluation phantom (Catphan 600) and an anthropomorphic head phantom. Results are compared to those generated using direct matrix inversion with no noise suppression, a de-noising method applied on the decomposed images, and an existing algorithm with similar formulation but with an edge-preserving regularization term. Results: On the Catphan phantom, our method retains the same spatial resolution as the CT images before decomposition while reducing the noise standard deviation of decomposed images by over 98%. The other methods either degrade spatial resolution or achieve less low-contrast detectability. Also, our method yields lower electron density measurement error than direct matrix inversion and reduces error variation by over 97%. On the head phantom, it reduces the noise standard deviation of decomposed images by over 97% without blurring the sinus structures. Conclusion: We propose an iterative image-domain decomposition method for DECT. The method combines noise suppression and material decomposition into an iterative

  15. Theoretical study of isomerization and decomposition of propenal

    SciTech Connect (OSTI)

    Chin, Chih-Hao; Lee, Shih-Huang

    2011-01-28

    We investigated the dynamics of isomerization and multi-channel dissociation of propenal (CH{sub 2}CHCHO), methyl ketene (CH{sub 3}CHCO), hydroxyl propadiene (CH{sub 2}CH{sub 2}CHOH), and hydroxyl cyclopropene (cyclic-C{sub 3}H{sub 3}-OH) in the ground potential-energy surface using quantum-chemical calculations. Optimized structures and vibrational frequencies of molecular species were computed with method B3LYP/6-311G(d,p). Total energies of molecules at optimized structures were computed at the CCSD(T)/6-311+G(3df,2p) level of theory. We established the potential-energy surface for decomposition to CH{sub 2}CHCO + H, CH{sub 2}CH + HCO, CH{sub 2}CH{sub 2}/CH{sub 3}CH + CO, CHCH/CH{sub 2}C + H{sub 2}CO, CHCCHO/CH{sub 2}CCO + H{sub 2}, CHCH + CO + H{sub 2}, CH{sub 3}+ HCCO, CH{sub 2}CCH + OH, and CH{sub 2}CC/cyclic-C{sub 3}H{sub 2}+ H{sub 2}O. Microcanonical rate coefficients of various reactions of trans-propenal with internal energies 148 and 182 kcal mol{sup -1} were calculated using Rice-Ramsperger-Kassel-Marcus and Variational transition state theories. Product branching ratios were derivable using numerical integration of kinetic master equations and the steady-state approximation. The concerted three-body dissociation of trans-propenal to fragments C{sub 2}H{sub 2}+ CO + H{sub 2} is the prevailing channel in present calculations. In contrast, C{sub 3}H{sub 3}O + H, C{sub 2}H{sub 3}+ HCO and C{sub 2}H{sub 4}+ CO were identified as major channels in the photolysis of trans-propenal. The discrepancy between calculations and experiments in product branching ratios indicates that the three major photodissociation channels occur mainly on an excited potential-energy surface whereas the other channels occur mainly on the ground potential-energy surface. This work provides profound insight in the mechanisms of isomerization and multichannel dissociation of the system C{sub 3}H{sub 4}O.

  16. Ab Initio Kinetics and Thermal Decomposition Mechanism of Mononitrobiuret and 1,5- Dinitrobiuret

    SciTech Connect (OSTI)

    Sun, Hongyan; Vaghjiani, Ghanshyam G.

    2015-05-26

    Mononitrobiuret (MNB) and 1,5-dinitrobiuret (DNB) are tetrazole-free, nitrogen-rich, energetic compounds. For the first time, a comprehensive ab initio kinetics study on the thermal decomposition mechanisms of MNB and DNB is reported here. In particular, the intramolecular interactions of amine H-atom with electronegative nitro O-atom and carbonyl O-atom have been analyzed for biuret, MNB, and DNB at the M06-2X/aug-cc-pVTZ level of theory. The results show that the MNB and DNB molecules are stabilized through six-member-ring moieties via intramolecular H-bonding with interatomic distances between 1.8 and 2.0 , due to electrostatic as well as polarization and dispersion interactions. Furthermore, it was found that the stable molecules in the solid state have the smallest dipole moment amongst all the conformers in the nitrobiuret series of compounds, thus revealing a simple way for evaluating reactivity of fuel conformers. The potential energy surface for thermal decomposition of MNB was characterized by spin restricted coupled cluster theory at the RCCSD(T)/cc-pV? Z//M06-2X/aug-cc-pVTZ level. It was found that the thermal decomposition of MNB is initiated by the elimination of HNCO and HNN(O)OH intermediates. Intramolecular transfer of a H-atom, respectively, from the terminal NH2 group to the adjacent carbonyl O-atom via a six-member-ring transition state eliminates HNCO with an energy barrier of 35 kcal/mol and from the central NH group to the adjacent nitro O-atom eliminates HNN(O)OH with an energy barrier of 34 kcal/mol. Elimination of HNN(O)OH is also the primary process involved in the thermal decomposition of DNB, which processes C2v symmetry. The rate coefficients for the primary decomposition channels for MNB and DNB were quantified as functions of temperature and pressure. In addition, the thermal decomposition of HNN(O)OH was analyzed via RiceRamspergerKasselMarcus/multi-well master equation simulations, the results of which reveal the formation of

  17. Ab initio kinetics and thermal decomposition mechanism of mononitrobiuret and 1,5-dinitrobiuret

    SciTech Connect (OSTI)

    Sun, Hongyan E-mail: ghanshyam.vaghjiani@us.af.mil; Vaghjiani, Ghanshyam L. E-mail: ghanshyam.vaghjiani@us.af.mil

    2015-05-28

    Mononitrobiuret (MNB) and 1,5-dinitrobiuret (DNB) are tetrazole-free, nitrogen-rich, energetic compounds. For the first time, a comprehensive ab initio kinetics study on the thermal decomposition mechanisms of MNB and DNB is reported here. In particular, the intramolecular interactions of amine H-atom with electronegative nitro O-atom and carbonyl O-atom have been analyzed for biuret, MNB, and DNB at the M06-2X/aug-cc-pVTZ level of theory. The results show that the MNB and DNB molecules are stabilized through six-member-ring moieties via intramolecular H-bonding with interatomic distances between 1.8 and 2.0 , due to electrostatic as well as polarization and dispersion interactions. Furthermore, it was found that the stable molecules in the solid state have the smallest dipole moment amongst all the conformers in the nitrobiuret series of compounds, thus revealing a simple way for evaluating reactivity of fuel conformers. The potential energy surface for thermal decomposition of MNB was characterized by spin restricted coupled cluster theory at the RCCSD(T)/cc-pV? Z//M06-2X/aug-cc-pVTZ level. It was found that the thermal decomposition of MNB is initiated by the elimination of HNCO and HNN(O)OH intermediates. Intramolecular transfer of a H-atom, respectively, from the terminal NH{sub 2} group to the adjacent carbonyl O-atom via a six-member-ring transition state eliminates HNCO with an energy barrier of 35 kcal/mol and from the central NH group to the adjacent nitro O-atom eliminates HNN(O)OH with an energy barrier of 34 kcal/mol. Elimination of HNN(O)OH is also the primary process involved in the thermal decomposition of DNB, which processes C{sub 2v} symmetry. The rate coefficients for the primary decomposition channels for MNB and DNB were quantified as functions of temperature and pressure. In addition, the thermal decomposition of HNN(O)OH was analyzed via RiceRamspergerKasselMarcus/multi-well master equation simulations, the results of which reveal the

  18. Lattice QCD with Domain Decomposition on Intel Xeon Phi Co-Processors

    SciTech Connect (OSTI)

    Heybrock, Simon; Joo, Balint; Kalamkar, Dhiraj D.; Smelyanskiy, Mikhail; Vaidyanathan, Karthikeyan; Wettig, Tilo; Dubey, Pradeep

    2014-12-01

    The gap between the cost of moving data and the cost of computing continues to grow, making it ever harder to design iterative solvers on extreme-scale architectures. This problem can be alleviated by alternative algorithms that reduce the amount of data movement. We investigate this in the context of Lattice Quantum Chromodynamics and implement such an alternative solver algorithm, based on domain decomposition, on Intel Xeon Phi co-processor (KNC) clusters. We demonstrate close-to-linear on-chip scaling to all 60 cores of the KNC. With a mix of single- and half-precision the domain-decomposition method sustains 400-500 Gflop/s per chip. Compared to an optimized KNC implementation of a standard solver [1], our full multi-node domain-decomposition solver strong-scales to more nodes and reduces the time-to-solution by a factor of 5.

  19. A Note on the Fisher Ideal Index Decomposition for Structural Change in Energy Intensity

    SciTech Connect (OSTI)

    Boyd, Gale A.; Roop, Joseph M.

    2004-01-01

    By direct appeal to the theory underlying price index numbers used by the energy decomposition literature, this note proposed the chain weighted Fisher Ideal Index as a formula that solves the ''residual problem;'' i.e., the decomposition is not complete in the sense that the components do not add to the whole. The connection to index number theory also allows us to illustrate that the measures of activity used to define energy intensity need not be additive across the sectors that are involved in the decomposition. We give an empirical example using recent U. S. manufacturing data of the Fisher Ideal Index, compared to the Tornquist Divisia Index, a popular index in the energy literature.

  20. Implementation of the singular-value decomposition on the Connection Machine CM-2

    SciTech Connect (OSTI)

    Chu, N.A.

    1991-04-11

    In modern digital signal processing, the singular value decomposition is increasingly recognized as an important mathematical tool. The true measure of usefulness of such a tool is very much dependent on the ability to compute it at supercomputer throughput rates. This report describes an implementation of the singular value decomposition (SVD) on the Connection Machine CM-2 using parallel Fortran. The algorithm is based on Hestenes's, which is a Jacobi iteration in which pairs of rows are rotated to become orthogonal. The Fortran implementation of this algorithm on a full CM-2 is comparable in execution speed to the Linpack implementation on a Convex C220 processor.

  1. Decomposition of chlorinated ethylenes and ethanes in an electron beam generated plasma reactor

    SciTech Connect (OSTI)

    Vitale, S.A.

    1996-02-01

    An electron beam generated plasma reactor (EBGPR) is used to determine the plasma chemistry kinetics, energetics and decomposition pathways of six chlorinated ethylenes and ethanes: 1,1,1-trichloroethane, 1,1-dichloroethane, ethyl chloride, trichloroethylene, 1,1-dichloroethylene, and vinyl chloride. A traditional chemical kinetic and chemical engineering analysis of the data from the EBGPR is performed, and the following hypothesis was verified: The specific energy required for chlorinated VOC decomposition in the electron beam generated plasma reactor is determined by the electron attachment coefficient of the VOC and the susceptibility of the molecule to radical attack. The technology was demonstrated at the Hanford Reservation to remove VOCs from soils.

  2. Oxidative Decomposition of Methanol on Subnanometer Palladium Clusters: The Effect of Catalyst Size and Support Composition

    SciTech Connect (OSTI)

    Lee, Sungsik; Lee, Byeongdu; Mehmood, Faisal; Seifert, Soenke; Libera, Joseph A.; Elam, J. W.; Greeley, Jeffrey P.; Zapol, Peter; Curtiss, Larry A.; Pellin, M. J.; Stair, Peter C.; Winans, R. E.; Vajda, S.

    2010-05-31

    Size and support effects in the oxidative decomposition of methanol on amorphous alumina supported subnanometer palladium clusters were studied under realistic reaction conditions of pressure and temperature. The smaller Pd8-12 clusters were found to promote the decomposition channel to CO and hydrogen, however with mediocre activity due to poisoning. The larger Pd15-18 clusters preferentially produce dimethyl ether and formaldehyde, without signs of posioning. A thin titania overcoat applied on the Pd15-18 improves the sintering-resistance of the catalyst. Accompanying density functional calculations confirm the posioning of small Pd clusters by CO.

  3. Oxidative decomposition of methanol on subnanometer palladium clusters : the effect of catalyst size and support composition.

    SciTech Connect (OSTI)

    Lee, S.; Lee, B.; Mehmood, F.; Seifert, S.; Libera, J. A.; Elam, J. W.; Greeley, J.; Zapol, P.; Curtiss, L. A.; Pellin, M. J.; Stair, P. C.; Winans, R. E; Vajda, S.; Northwestern Univ.

    2010-06-17

    Size and support effects in the oxidative decomposition of methanol on amorphous alumina supported subnanometer palladium clusters were studied under realistic reaction conditions of pressure and temperature. The smaller Pd{sub 8-12} clusters were found to promote the decomposition channel to CO and hydrogen, however with mediocre activity due to poisoning. The larger Pd{sub 15-18} clusters preferentially produce dimethyl ether and formaldehyde, without signs of posioning. A thin titania overcoat applied on the Pd{sub 15-18} improves the sintering-resistance of the catalyst. Accompanying density functional calculations confirm the posioning of small Pd clusters by CO.

  4. Controlled thermal decomposition of NaSi to derive silicon clathrate compounds

    SciTech Connect (OSTI)

    Horie, Hiro-omi; Kikudome, Takashi; Teramura, Kyosuke; Yamanaka, Shoji

    2009-01-15

    Formation conditions of two types of sodium containing silicon clathrate compounds were determined by the controlled thermal decomposition of sodium monosilicide NaSi under vacuum. The decomposition began at 360 deg. C. Much higher decomposition temperatures and the presence of sodium metal vapor were favorable for the formation of type I clathrate compound Na{sub 8}Si{sub 46}. Type II clathrate compound Na{sub x}Si{sub 136} was obtained as a single phase at a decomposition temperature <440 deg. C under the condition without sodium metal vapor. The type I clathrate compound was decomposed to crystalline Si above 520 deg. C. The type II clathrate compound was thermally more stable, and retained at least up to 550 deg. C in vacuum. - Graphical Abstract: The optimal condition to prepare type II silicon clathrate Na{sub x}Si{sub 136} with minimal contamination of the type I phase is proposed. The starting NaSi should be thermally decomposed below 440 deg. C, and the rapid removal of Na vapor evolved is essentially important.

  5. Photogeneration of active formate decomposition catalysts to produce hydrogen from formate and water

    DOE Patents [OSTI]

    King, Jr., Allen D.; King, Robert B.; Sailers, III, Earl L.

    1983-02-08

    A process for producing hydrogen from formate and water by photogenerating an active formate decomposition catalyst from transition metal carbonyl precursor catalysts at relatively low temperatures and otherwise mild conditions is disclosed. Additionally, this process may be expanded to include the generation of formate from carbon monoxide and hydroxide such that the result is the water gas shift reaction.

  6. PROCESS OF COATING WITH NICKEL BY THE DECOMPOSITION OF NICKEL CARBONYL

    DOE Patents [OSTI]

    Hoover, T.B.

    1959-04-01

    An improved process is presented for the deposition of nickel coatings by the thermal decomposition of nickel carbonyl vapor. The improvement consists in incorporating a small amount of hydrogen sulfide gas in the nickel carbonyl plating gas. It is postulated that the hydrogen sulfide functions as a catalyst. i

  7. Comparative Density Functional Study of Methanol Decomposition on Cu4 and Co4 Clusters

    SciTech Connect (OSTI)

    Mehmood, Faisal; Greeley, Jeffrey P.; Zapol, Peter; Curtiss, Larry A.

    2010-11-18

    A density functional theory study of the decomposition of methanol on Cu4 and Co4 clusters is presented. The reaction intermediates and activation barriers have been determined for reaction steps to form H2 and CO. For both clusters, methanol decomposition initiated by C-H and O-H bond breaking was investigated. In the case of a Cu4 cluster, methanol dehydrogenation through hydroxymethyl (CH2OH), hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO) is found to be slightly more favorable. For a Co4 cluster, the dehydrogenation pathway through methoxy (CH3O) and formaldehyde (CH2O) is slightly more favorable. Each of these pathways results in formation of CO and H2. The Co cluster pathway is very favorable thermodynamically and kinetically for dehydrogenation. However, since CO binds strongly, it is likely to poison methanol decomposition to H2 and CO at low temperatures. In contrast, for the Cu cluster, CO poisoning is not likely to be a problem since it does not bind strongly, but the dehydrogenation steps are not energetically favorable. Pathways involving C-O bond cleavage are even less energetically favorable. The results are compared to our previous study of methanol decomposition on Pd4 and Pd8 clusters. Finally, all reaction energy changes and transition state energies, including those for the Pd clusters, are related in a linear, Broensted-Evans-Polanyi plot.

  8. Hydrate decomposition conditions in the system hydrogen sulfide-methane, and propane

    SciTech Connect (OSTI)

    Schroeter, J.P.; Kobayashi, R.; Hildebrand, H.A.

    1982-12-01

    Experimental hydrate decomposition conditions are presented for 3 different H/sub 2/S-containing mixtures in the temperature region 0 C to 30 C. The 3 mixtures investigated were 4% H/sub 2/S, 7% propane, 89% methane; 12% H/sub 2/S, 7% propane, 81% methane; and 30% H/sub 2/S, 7% propane, 63% methane. Hydrate decomposition pressures and temperatures were obtained for each of these mixtures by observation of the pressure-temperature hysteresis curves associated with formation and decomposition of the hydrate crystals. A repeatable decomposition point was observed in every case, and this was identified as the hydrate point. The results for the 4% H/sub 2/S mixture were used to adjust parameters in a computer model based on the Parrish and Prausnitz statistical thermodynamics method, coupled with the BWRS equation of state. After the parameter adjustment, the computer model predicted the behavior of the 12% H/sub 2/S and the 30% H/sub 2/S mixtures to within 2 C. Experimental data for the 3 mixtures are given.

  9. Method of forming semiconducting amorphous silicon films from the thermal decomposition of fluorohydridodisilanes

    DOE Patents [OSTI]

    Sharp, Kenneth G.; D'Errico, John J.

    1988-01-01

    The invention relates to a method of forming amorphous, photoconductive, and semiconductive silicon films on a substrate by the vapor phase thermal decomposition of a fluorohydridodisilane or a mixture of fluorohydridodisilanes. The invention is useful for the protection of surfaces including electronic devices.

  10. Decomposition of toluene in a steady-state atmospheric-pressure glow discharge

    SciTech Connect (OSTI)

    Trushkin, A. N.; Grushin, M. E.; Kochetov, I. V.; Trushkin, N. I.; Akishev, Yu. S.

    2013-02-15

    Results are presented from experimental studies of decomposition of toluene (C{sub 6}H{sub 5}CH{sub 3}) in a polluted air flow by means of a steady-state atmospheric pressure glow discharge at different water vapor contents in the working gas. The experimental results on the degree of C{sub 6}H{sub 5}CH{sub 3} removal are compared with the results of computer simulations conducted in the framework of the developed kinetic model of plasma chemical decomposition of toluene in the N{sub 2}: O{sub 2}: H{sub 2}O gas mixture. A substantial influence of the gas flow humidity on toluene decomposition in the atmospheric pressure glow discharge is demonstrated. The main mechanisms of the influence of humidity on C{sub 6}H{sub 5}CH{sub 3} decomposition are determined. The existence of two stages in the process of toluene removal, which differ in their duration and the intensity of plasma chemical decomposition of C{sub 6}H{sub 5}CH{sub 3} is established. Based on the results of computer simulations, the composition of the products of plasma chemical reactions at the output of the reactor is analyzed as a function of the specific energy deposition and gas flow humidity. The existence of a catalytic cycle in which hydroxyl radical OH acts a catalyst and which substantially accelerates the recombination of oxygen atoms and suppression of ozone generation when the plasma-forming gas contains water vapor is established.

  11. CPUF - a chemical-structure-based polyurethane foam decomposition and foam response model.

    SciTech Connect (OSTI)

    Fletcher, Thomas H. (Brigham Young University, Provo, UT); Thompson, Kyle Richard; Erickson, Kenneth L.; Dowding, Kevin J.; Clayton, Daniel (Brigham Young University, Provo, UT); Chu, Tze Yao; Hobbs, Michael L.; Borek, Theodore Thaddeus III

    2003-07-01

    A Chemical-structure-based PolyUrethane Foam (CPUF) decomposition model has been developed to predict the fire-induced response of rigid, closed-cell polyurethane foam-filled systems. The model, developed for the B-61 and W-80 fireset foam, is based on a cascade of bondbreaking reactions that produce CO2. Percolation theory is used to dynamically quantify polymer fragment populations of the thermally degrading foam. The partition between condensed-phase polymer fragments and gas-phase polymer fragments (i.e. vapor-liquid split) was determined using a vapor-liquid equilibrium model. The CPUF decomposition model was implemented into the finite element (FE) heat conduction codes COYOTE and CALORE, which support chemical kinetics and enclosure radiation. Elements were removed from the computational domain when the calculated solid mass fractions within the individual finite element decrease below a set criterion. Element removal, referred to as ?element death,? creates a radiation enclosure (assumed to be non-participating) as well as a decomposition front, which separates the condensed-phase encapsulant from the gas-filled enclosure. All of the chemistry parameters as well as thermophysical properties for the CPUF model were obtained from small-scale laboratory experiments. The CPUF model was evaluated by comparing predictions to measurements. The validation experiments included several thermogravimetric experiments at pressures ranging from ambient pressure to 30 bars. Larger, component-scale experiments were also used to validate the foam response model. The effects of heat flux, bulk density, orientation, embedded components, confinement and pressure were measured and compared to model predictions. Uncertainties in the model results were evaluated using a mean value approach. The measured mass loss in the TGA experiments and the measured location of the decomposition front were within the 95% prediction limit determined using the CPUF model for all of the

  12. A literature review of radiolytic gas generation as a result of the decomposition of sodium nitrate wastes

    SciTech Connect (OSTI)

    Kasten, J.L.

    1991-01-01

    The objective of this literature review is to determine expected chemical reactions and the gas generation associated with radiolytic decomposition of radioactive sodium nitrate wastes such as the wastes stored in the Melton Valley Storage Tanks (MVST) at Oak Ridge National Laboratory (ORNL). The literature survey summarizes expected chemical reactions and identifies the gases expected to be generated as a result of the radiolytic decomposition. The literature survey also identifies G values, which are the expression for radiation chemical yields as molecules of gas formed per 100 eV of absorbed energy, obtained from experimental studies of the radiolytic decomposition of water and sodium nitrate. 2 tabs., 32 refs.

  13. Kinetics of Methane Hydrate Decomposition Studied via in Situ Low Temperature X-ray Powder Diffraction

    SciTech Connect (OSTI)

    Everett, Susan M; Rawn, Claudia J; Keffer, David J.; Mull, Derek L; Payzant, E Andrew; Phelps, Tommy Joe

    2013-01-01

    Gas hydrates are known to have a slowed decomposition rate at ambient pressure and temperatures below the melting point of ice termed self-preservation or anomalous preservation. As hydrate exothermically decomposes, gas is released and water of the clathrate cages transforms into ice. Two regions of slowed decomposition for methane hydrate, 180 200 K and 230 260 K, were observed, and the kinetics were studied by in situ low temperature x-ray powder diffraction. The kinetic constants for ice formation from methane hydrate were determined by the Avrami model within each region and activation energies, Ea, were determined by the Arrhenius plot. Ea determined from the data for 180 200 K was 42 kJ/mol and for 230 260 K was 22 kJ/mol. The higher Ea in the colder temperature range was attributed to a difference in the microstructure of ice between the two regions.

  14. Controllable pneumatic generator based on the catalytic decomposition of hydrogen peroxide

    SciTech Connect (OSTI)

    Kim, Kyung-Rok; Kim, Kyung-Soo Kim, Soohyun

    2014-07-15

    This paper presents a novel compact and controllable pneumatic generator that uses hydrogen peroxide decomposition. A fuel micro-injector using a piston-pump mechanism is devised and tested to control the chemical decomposition rate. By controlling the injection rate, the feedback controller maintains the pressure of the gas reservoir at a desired pressure level. Thermodynamic analysis and experiments are performed to demonstrate the feasibility of the proposed pneumatic generator. Using a prototype of the pneumatic generator, it takes 6 s to reach 3.5 bars with a reservoir volume of 200 ml at the room temperature, which is sufficiently rapid and effective to maintain the repetitive lifting of a 1 kg mass.

  15. Pathways of anaerobic organic matter decomposition in tundra soils from Barrow, Alaska

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

    Herndon, Elizabeth M.; Mann, Benjamin F.; Chowdhury, Taniya Roy; Wullschleger, Stan D.; Graham, David E.; Liang, Liyuan; Gu, Baohua; Yang, Ziming

    2015-11-23

    Arctic tundra soils store a large quantity of organic carbon that is susceptible to decomposition and release to the atmosphere as methane (CH4) and carbon dioxide (CO2) under a warming climate. Anaerobic processes that generate CH4 and CO2 remain unclear because previous studies have focused on aerobic decomposition pathways. To predict releases of CO2 and CH4 from tundra soils, it is necessary to identify pathways of soil organic matter decomposition under the anoxic conditions that are prevalent in Arctic ecosystems. Here molecular and spectroscopic techniques were used to monitor biological degradation of water-extractable organic carbon (WEOC) during anoxic incubation ofmore » tundra soils from a region of continuous permafrost in northern Alaska. Organic and mineral soils from the tundra active layer were incubated at –2, +4, or +8°C for up to 60 days to mimic the short-term thaw season. Results suggest that, under anoxic conditions, fermentation converted complex organic molecules into simple organic acids that were used in concomitant Fe-reduction and acetoclastic methanogenesis reactions. Nonaromatic compounds increased over time as WEOC increased. Organic acid metabolites initially accumulated in soils but were mostly depleted by day 60 because organic acids were consumed to produce Fe(II), CO2, and CH4. We conclude that fermentation of nonprotected organic matter facilitates methanogenesis and Fe reduction reactions, and that the proportion of organic acids consumed by methanogenesis increases relative to Fe reduction with increasing temperature. As a result, the decomposition pathways observed in this study are important to consider in numerical modeling of greenhouse gas production in the Arctic.« less

  16. Catalytic decomposition of Ba(NO3)2 on Pt(111)

    SciTech Connect (OSTI)

    Mudiyanselage, Kumudu; Weaver, Jason F.; Szanyi, Janos

    2011-04-07

    The decomposition of Ba(NO3)2 formed on BaO/Pt(111) (Pt(111) surface is partially covered by BaO) in the presence of CO was studied using temperature programmed desorption (TPD), infrared reflection absorption (IRA) and X-ray photoelectron (XP) spectroscopies. The exposure of BaO/Pt(111) to elevated NO2 pressure (1.0×10-4 Torr) at 450 K leads to the formation of Ba(NO3)2, chemisorbed O (OPt) and Pt-oxide-like domains. During TPD, the Ba(NO3)2 begins to thermally decompose near 490 K, releasing NO and NO2 with the maximum NOx desorption rate seen at 605 K. The OPt species formed following the exposure of BaO/Pt(111) to NO2 react with CO to release CO2 at 450 K. The consumption of OPt during CO oxidation initiates the migration of O from the Pt-oxide-like domains to the chemisorbed phase, where the CO oxidation reaction occurs. Therefore, the removal of OPt by CO leads to the reduction of oxidized Pt, and to the formation of metallic Pt(111) domains, where, subsequently, catalytic decomposition of Ba(NO3)2 can take place. The Pt-catalyzed decomposition of Ba(NO3)2 occurs readily at 450 K, a temperature much lower than the onset of the decomposition temperature of Ba(NO3)2 in the presence of oxidized Pt. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  17. Pathways of anaerobic organic matter decomposition in tundra soils from Barrow, Alaska

    SciTech Connect (OSTI)

    Herndon, Elizabeth M.; Mann, Benjamin F.; Chowdhury, Taniya Roy; Wullschleger, Stan D.; Graham, David E.; Liang, Liyuan; Gu, Baohua; Yang, Ziming

    2015-11-23

    Arctic tundra soils store a large quantity of organic carbon that is susceptible to decomposition and release to the atmosphere as methane (CH4) and carbon dioxide (CO2) under a warming climate. Anaerobic processes that generate CH4 and CO2 remain unclear because previous studies have focused on aerobic decomposition pathways. To predict releases of CO2 and CH4 from tundra soils, it is necessary to identify pathways of soil organic matter decomposition under the anoxic conditions that are prevalent in Arctic ecosystems. Here molecular and spectroscopic techniques were used to monitor biological degradation of water-extractable organic carbon (WEOC) during anoxic incubation of tundra soils from a region of continuous permafrost in northern Alaska. Organic and mineral soils from the tundra active layer were incubated at –2, +4, or +8°C for up to 60 days to mimic the short-term thaw season. Results suggest that, under anoxic conditions, fermentation converted complex organic molecules into simple organic acids that were used in concomitant Fe-reduction and acetoclastic methanogenesis reactions. Nonaromatic compounds increased over time as WEOC increased. Organic acid metabolites initially accumulated in soils but were mostly depleted by day 60 because organic acids were consumed to produce Fe(II), CO2, and CH4. We conclude that fermentation of nonprotected organic matter facilitates methanogenesis and Fe reduction reactions, and that the proportion of organic acids consumed by methanogenesis increases relative to Fe reduction with increasing temperature. As a result, the decomposition pathways observed in this study are important to consider in numerical modeling of greenhouse gas production in the Arctic.

  18. Hazardous materials: Microbiological decomposition. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1993-12-01

    The bibliography contains citations concerning the decomposition of toxic materials by biological means. Bacteria, enzymes, and bioluminescence are among the methods discussed. Bacteria and enzymes that digest toluene, polychlorinated biphenyls (PCBs), selenium wastes, oil shale waste, uranium, oil sludge, pesticides, rubber wastes, and pentachlorophenol are discussed. Flavobacterium and white rot fungus are among the biological agents highlighted. (Contains 250 citations and includes a subject term index and title list.)

  19. Hazardous materials: Microbiological decomposition. (Latest citations from the Biobusiness database). NewSearch

    SciTech Connect (OSTI)

    Not Available

    1994-10-01

    The bibliography contains citations concerning the decomposition of toxic materials by biological means. Bacteria, enzymes, and bioluminescence are among the methods discussed. Bacteria and enzymes that digest toluene, polychlorinated biphenyls (PCBs), selenium wastes, oil shale waste, uranium, oil sludge, pesticides, rubber wastes, and pentachlorophenol are discussed. Flavobacterium and white rot fungus are among the biological agents highlighted. (Contains 250 citations and includes a subject term index and title list.)

  20. Substrate decomposition in galvanic displacement reaction: Contrast between gold and silver nanoparticle formation

    SciTech Connect (OSTI)

    Ghosh, Tapas; Satpati, Biswarup

    2015-06-24

    We have investigated substrate decomposition during formation of silver and gold nanoparticles in galvanic displacement reaction on germanium surfaces. Silver and gold nanoparticles were synthesized by electroless deposition on sputter coated germanium thin film (∼ 200 nm) grown initially on silicon substrate. The nanoparticles formation and the substrate corrosion were studied using scanning transmission electron microscopy (STEM) and the energy dispersive X-ray (EDX) spectroscopy.

  1. Algebraic multigrid domain and range decomposition (AMG-DD / AMG-RD)*

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

    Bank, R.; Falgout, R. D.; Jones, T.; Manteuffel, T. A.; McCormick, S. F.; Ruge, J. W.

    2015-10-29

    In modern large-scale supercomputing applications, algebraic multigrid (AMG) is a leading choice for solving matrix equations. However, the high cost of communication relative to that of computation is a concern for the scalability of traditional implementations of AMG on emerging architectures. This paper introduces two new algebraic multilevel algorithms, algebraic multigrid domain decomposition (AMG-DD) and algebraic multigrid range decomposition (AMG-RD), that replace traditional AMG V-cycles with a fully overlapping domain decomposition approach. While the methods introduced here are similar in spirit to the geometric methods developed by Brandt and Diskin [Multigrid solvers on decomposed domains, in Domain Decomposition Methods inmore » Science and Engineering, Contemp. Math. 157, AMS, Providence, RI, 1994, pp. 135--155], Mitchell [Electron. Trans. Numer. Anal., 6 (1997), pp. 224--233], and Bank and Holst [SIAM J. Sci. Comput., 22 (2000), pp. 1411--1443], they differ primarily in that they are purely algebraic: AMG-RD and AMG-DD trade communication for computation by forming global composite “grids” based only on the matrix, not the geometry. (As is the usual AMG convention, “grids” here should be taken only in the algebraic sense, regardless of whether or not it corresponds to any geometry.) Another important distinguishing feature of AMG-RD and AMG-DD is their novel residual communication process that enables effective parallel computation on composite grids, avoiding the all-to-all communication costs of the geometric methods. The main purpose of this paper is to study the potential of these two algebraic methods as possible alternatives to existing AMG approaches for future parallel machines. As a result, this paper develops some theoretical properties of these methods and reports on serial numerical tests of their convergence properties over a spectrum of problem parameters.« less

  2. Algebraic multigrid domain and range decomposition (AMG-DD / AMG-RD)*

    SciTech Connect (OSTI)

    Bank, R.; Falgout, R. D.; Jones, T.; Manteuffel, T. A.; McCormick, S. F.; Ruge, J. W.

    2015-10-29

    In modern large-scale supercomputing applications, algebraic multigrid (AMG) is a leading choice for solving matrix equations. However, the high cost of communication relative to that of computation is a concern for the scalability of traditional implementations of AMG on emerging architectures. This paper introduces two new algebraic multilevel algorithms, algebraic multigrid domain decomposition (AMG-DD) and algebraic multigrid range decomposition (AMG-RD), that replace traditional AMG V-cycles with a fully overlapping domain decomposition approach. While the methods introduced here are similar in spirit to the geometric methods developed by Brandt and Diskin [Multigrid solvers on decomposed domains, in Domain Decomposition Methods in Science and Engineering, Contemp. Math. 157, AMS, Providence, RI, 1994, pp. 135--155], Mitchell [Electron. Trans. Numer. Anal., 6 (1997), pp. 224--233], and Bank and Holst [SIAM J. Sci. Comput., 22 (2000), pp. 1411--1443], they differ primarily in that they are purely algebraic: AMG-RD and AMG-DD trade communication for computation by forming global composite “grids” based only on the matrix, not the geometry. (As is the usual AMG convention, “grids” here should be taken only in the algebraic sense, regardless of whether or not it corresponds to any geometry.) Another important distinguishing feature of AMG-RD and AMG-DD is their novel residual communication process that enables effective parallel computation on composite grids, avoiding the all-to-all communication costs of the geometric methods. The main purpose of this paper is to study the potential of these two algebraic methods as possible alternatives to existing AMG approaches for future parallel machines. As a result, this paper develops some theoretical properties of these methods and reports on serial numerical tests of their convergence properties over a spectrum of problem parameters.

  3. Dynamic load balancing algorithm for molecular dynamics based on Voronoi cells domain decompositions

    SciTech Connect (OSTI)

    Fattebert, J.-L.; Richards, D.F.; Glosli, J.N.

    2012-12-01

    We present a new algorithm for automatic parallel load balancing in classical molecular dynamics. It assumes a spatial domain decomposition of particles into Voronoi cells. It is a gradient method which attempts to minimize a cost function by displacing Voronoi sites associated with each processor/sub-domain along steepest descent directions. Excellent load balance has been obtained for quasi-2D and 3D practical applications, with up to 440106 particles on 65,536 MPI tasks.

  4. A quasimechanism of melt acceleration in the thermal decomposition of crystalline organic solids

    SciTech Connect (OSTI)

    Henson, Bryan F

    2009-01-01

    It has been know for half a century that many crystalline organic solids undergo an acceleration in the rate of thermal decomposition as the melting temperature is approached. This acceleration terminates at the melting point, exhibiting an Arrhenius-like temperature dependence in the faster decomposition rate from the liquid phase. This observation has been modeled previously using various premelting behaviors based on e.g. freezing point depression induced by decomposition products or solvent impurities. These models do not, however, indicate a mechanism for liquid formation and acceleration which is an inherent function of the bulk thermodynamics of the molecule. Here we show that such an inherent thermodynamic mechanism for liquid formation exists in the form of the so-called quasi-liquid layer at the solid surface. We explore a kinetic mechanism which describes the acceleration of rate and is a function of the free energies of sublimation and vaporization. We construct a differential rate law from these thermodynamic free energies and a normalized progress variable. We further construct a reduced variable formulation of the model which is a simple function of the metastable liquid activity below the melting point, and show that it is applicable to the observed melt acceleration in several common organic crystalline solids. A component of the differential rate law, zero order in the progress variable, is shown to be proportional to the thickness of the quasiliquid layer predicted by a recent thermodynamic theory for this phenomenon. This work therefore serves not only to provide new insight into thermal decomposition in a broad class or organic crystalline solids, but also further validates the underlying thermodynamic nature of the phenomenon of liquid formation on the molecular surface at temperatures below the melting point.

  5. On the Site-Decomposition of Magnetocrystalline Anisotropy Energy Using Ome-Electron Eigenstates

    SciTech Connect (OSTI)

    Aberg, Daniel; Sadigh, Babak; Benedict, Lorin X.

    2015-10-26

    We discuss two di erent schemes for decomposing the magnetocrystalline anisotropy energy into atomic site-speci c contributions, and show that one of these, which uses projected single-particle states, is inherently ill-de ned in practical applications. We therefore argue that the other decomposition scheme, involving ground state matrix elements of the spin-orbit operator, is preferable for the numerical prediction of one-site contributions to the anisotropy.

  6. Calculation of excitation energies from the CC2 linear response theory using Cholesky decomposition

    SciTech Connect (OSTI)

    Baudin, Pablo; qLEAP Center for Theoretical Chemistry, Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C ; Marn, Jos Snchez; Cuesta, Inmaculada Garca; Snchez de Mers, Alfredo M. J.

    2014-03-14

    A new implementation of the approximate coupled cluster singles and doubles CC2 linear response model is reported. It employs a Cholesky decomposition of the two-electron integrals that significantly reduces the computational cost and the storage requirements of the method compared to standard implementations. Our algorithm also exploits a partitioning form of the CC2 equations which reduces the dimension of the problem and avoids the storage of doubles amplitudes. We present calculation of excitation energies of benzene using a hierarchy of basis sets and compare the results with conventional CC2 calculations. The reduction of the scaling is evaluated as well as the effect of the Cholesky decomposition parameter on the quality of the results. The new algorithm is used to perform an extrapolation to complete basis set investigation on the spectroscopically interesting benzylallene conformers. A set of calculations on medium-sized molecules is carried out to check the dependence of the accuracy of the results on the decomposition thresholds. Moreover, CC2 singlet excitation energies of the free base porphin are also presented.

  7. Hydrogen-terminated silicon nanowire photocatalysis: Benzene oxidation and methyl red decomposition

    SciTech Connect (OSTI)

    Lian, Suoyuan; School of Chemical Engineering and Materials, Dalian Polytechnic University, Dalian 116034 ; Tsang, Chi Him A.; Centre of Super Diamond and Advanced Films, City University of Hong Kong, Hong Kong ; Kang, Zhenhui; Liu, Yang; Wong, Ningbew; Lee, Shuit-Tong; Centre of Super Diamond and Advanced Films, City University of Hong Kong, Hong Kong

    2011-12-15

    Graphical abstract: H-SiNWs can catalyze hydroxylation of benzene and degradation of methyl red under visible light irradiation. Highlights: Black-Right-Pointing-Pointer Hydrogen-terminated silicon nanowires were active photocatalyst in the hydroxylation of benzene under light. Black-Right-Pointing-Pointer Hydrogen-terminated silicon nanowires were also effective in the decomposition of methyl red dye. Black-Right-Pointing-Pointer The Si/SiO{sub x} core-shell structure is the main reason of the obtained high selectivity during the hydroxylation. -- Abstract: Hydrogen-terminated silicon nanowires (H-SiNWs) were used as heterogeneous photocatalysts for the hydroxylation of benzene and for the decomposition of methyl red under visible light irradiation. The above reactions were monitored by GC-MS and UV-Vis spectrophotometry, respectively, which shows 100% selectivity for the transformation of benzene to phenol. A complete decomposition of a 2 Multiplication-Sign 10{sup -4} M methyl red solution was achieved within 30 min. The high selectivity for the hydroxylation of benzene and the photodecomposition demonstrate the catalytic activity of ultrafine H-SiNWs during nanocatalysis.

  8. Decomposition pathways of C2 oxygenates on Rh-modified tungsten carbide surfaces

    SciTech Connect (OSTI)

    Kelly, Thomas G.; Ren, Hui; Chen, Jingguang G.

    2015-03-27

    Ethanol decomposition on tungsten monocarbide (WC) and Rh-modified WC was investigated using ultrahigh vacuum (UHV) surface science experiments and density functional theory (DFT) calculations. DFT calculations indicated that the binding energies of ethanol and its decomposition intermediates on WC(0001) were modified by Rh, with Rh/WC(0001) showing similar values to those on Rh(111). Through temperature-programmed desorption (TPD) experiments on polycrystalline WC and Rh-modified WC, it was shown that the selectivity for ethanol decomposition was different on these surfaces. On WC, the C-O bond of ethanol was preferentially broken to produce ethylene; on Rh-modified WC, the C-C bond was broken to produce carbon monoxide and methane. In addition, high-resolution electron energy loss spectroscopy (HREELS) was used to determine likely surface intermediates. On Rh-modified WC, ethanol first formed ethoxy through O-H scission, then reacted through an aldehyde intermediate to form the C1 products.

  9. Trends in Formic Acid Decomposition on Model Transition Metal Surfaces: A Density Functional Theory Study

    SciTech Connect (OSTI)

    Herron, Jeffrey A.; Scaranto, Jessica; Ferrin, Peter A.; Li, Sha; Mavrikakis, Manos

    2014-12-05

    We present a first-principles, self-consistent periodic density functional theory (PW91-GGA) study of formic acid (HCOOH) decomposition on model (111) and (100) facets of eight fcc metals (Au, Ag, Cu, Pt, Pd, Ni, Ir, and Rh) and (0001) facets of four hcp (Co, Os, Ru, and Re) metals. The calculated binding energies of key formic acid decomposition intermediates including formate (HCOO), carboxyl (COOH), carbon monoxide (CO), water (H2O), carbon dioxide (CO2), hydroxyl (OH), carbon (C), oxygen (O), and hydrogen (H; H2) are presented. Using these energetics, we develop thermochemical potential energy diagrams for both the carboxyl-mediated and the formate-mediated dehydrogenation mechanisms on each surface. We evaluate the relative stability of COOH, HCOO, and other isomeric intermediates (i.e., CO + OH, CO2 + H, CO + O + H) on these surfaces. These results provide insights into formic acid decomposition selectivity (dehydrogenation versus dehydration), and in conjunction with calculated vibrational frequency modes, the results can assist with the experimental search for the elusive carboxyl (COOH) surface intermediate. Results are compared against experimental reports in the literature.

  10. DIRECT DECOMPOSITION OF METHANE TO HYDROGEN ON METAL LOADED ZEOLITE CATALYST

    SciTech Connect (OSTI)

    Lucia M. Petkovic; Daniel M. Ginosar; Kyle C. Burch; Harry W. Rollins

    2005-08-01

    The manufacture of hydrogen from natural gas is essential for the production of ultra clean transportation fuels. Not only is hydrogen necessary to upgrade low quality crude oils to high-quality, low sulfur ultra clean transportation fuels, hydrogen could eventually replace gasoline and diesel as the ultra clean transportation fuel of the future. Currently, refinery hydrogen is produced through the steam reforming of natural gas. Although efficient, the process is responsible for a significant portion of refinery CO2 emissions. This project is examining the direct catalytic decomposition of methane as an alternative to steam reforming. The energy required to produce one mole of hydrogen is slightly lower and the process does not require water-gas-shift or pressure-swing adsorption units. The decomposition process does not produce CO2 emissions and the product is not contaminated with CO -- a poison for PEM fuel cells. In this work we examined the direct catalytic decomposition of methane over a metal modified zeolite catalyst and the recovery of catalyst activity by calcination. A favorable production of hydrogen was obtained, when compared with previously reported nickel-zeolite supported catalysts. Reaction temperature had a strong influence on catalyst activity and on the type of carbon deposits. The catalyst utilized at 873 and 973 K could be regenerated without any significant loss of activity, however the catalyst utilized at 1073 K showed some loss of activity after regeneration.

  11. Decomposition pathways of C2 oxygenates on Rh-modified tungsten carbide surfaces

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

    Kelly, Thomas G.; Ren, Hui; Chen, Jingguang G.

    2015-03-27

    Ethanol decomposition on tungsten monocarbide (WC) and Rh-modified WC was investigated using ultrahigh vacuum (UHV) surface science experiments and density functional theory (DFT) calculations. DFT calculations indicated that the binding energies of ethanol and its decomposition intermediates on WC(0001) were modified by Rh, with Rh/WC(0001) showing similar values to those on Rh(111). Through temperature-programmed desorption (TPD) experiments on polycrystalline WC and Rh-modified WC, it was shown that the selectivity for ethanol decomposition was different on these surfaces. On WC, the C-O bond of ethanol was preferentially broken to produce ethylene; on Rh-modified WC, the C-C bond was broken to producemore » carbon monoxide and methane. In addition, high-resolution electron energy loss spectroscopy (HREELS) was used to determine likely surface intermediates. On Rh-modified WC, ethanol first formed ethoxy through O-H scission, then reacted through an aldehyde intermediate to form the C1 products.« less

  12. Target characterization using decomposition of the time-reversal operator: electromagnetic scattering from small ellipsoids

    SciTech Connect (OSTI)

    Chambers, D H; Berryman, J G

    2006-05-18

    Decomposition of the time-reversal operator for an array, or equivalently the singular value decomposition of the multistatic response matrix, has been used to improve imaging and localization of targets in complicated media. Typically, each singular value is associated with one scatterer even though it has been shown in several cases that a single scatterer can generate several singular values. In earlier papers Chambers and Berryman [1, 2] showed that a small spherical scatterer can generate up to six singular values depending on the array geometry and sphere composition. It was shown that the existence and characteristics of multiple singular values for each scatterer can, in principle, be used to determine certain properties of the scatterers, e.g. conducting or non-conducting material. In this paper, we extend this analysis to non-spherical targets and show how orientation information about the target may be obtained from the spectrum of singular values. The general properties of the decomposition for small non-spherical dielectric (and possibly conductive) targets in an electromagnetic field are derived and detailed results are obtained for the specific cases of non-magnetic and perfectly conducting needles and disks. It is shown that scatterer orientation can be estimated by tracking the singular values of a linear array as it is rotated around its midpoint.

  13. The spinodal decomposition in 17-4PH stainless steel subjected to long-term aging at 350 deg. C

    SciTech Connect (OSTI)

    Wang Jun Zou Hong; Li Cong; Qiu Shaoyu; Shen Baoluo

    2008-05-15

    The influence of aging time on the microstructure evolution of 17-4 PH martensitic stainless steel was studied by transmission electron microscopy (TEM). Results showed that the martensite decomposed by a spinodal decomposition mechanism after the alloy was subjected to long-term aging at 350 deg. C. The fine scale spinodal decomposition of {alpha}-ferrite brought about a Cr-enriched bright stripe and a Fe-enriched dark stripe, i.e., {alpha}' and {alpha} phases, separately, which were perpendicular to the grain boundary. The spinodal decomposition started at the grain boundary. Then with prolonged aging time, the decomposition microstructure expanded from the grain boundary to interior. The wavelength of the spinodally decomposed microstructure changed little with extended aging time.

  14. The response of the HMX-based material PBXN-9 to thermal insults: thermal decomposition kinetics and morphological changes

    SciTech Connect (OSTI)

    Glascoe, E A; Hsu, P C; Springer, H K; DeHaven, M R; Tan, N; Turner, H C

    2010-12-10

    PBXN-9, an HMX-formulation, is thermally damaged and thermally decomposed in order to determine the morphological changes and decomposition kinetics that occur in the material after mild to moderate heating. The material and its constituents were decomposed using standard thermal analysis techniques (DSC and TGA) and the decomposition kinetics are reported using different kinetic models. Pressed parts and prill were thermally damaged, i.e. heated to temperatures that resulted in material changes but did not result in significant decomposition or explosion, and analyzed. In general, the thermally damaged samples showed a significant increase in porosity and decrease in density and a small amount of weight loss. These PBXN-9 samples appear to sustain more thermal damage than similar HMX-Viton A formulations and the most likely reasons are the decomposition/evaporation of a volatile plasticizer and a polymorphic transition of the HMX from {beta} to {delta} phase.

  15. Decomposition of 1,1-Dichloroethane and 1,1-Dichloroethene in an electron beam generated plasma reactor

    SciTech Connect (OSTI)

    Vitale, S.A.; Hadidi, K.; Cohn, D.R.; Bromberg, L.

    1997-03-01

    An electron beam generated plasma reactor is used to decompose low concentrations (100{endash}3000 ppm) of 1,1-dichloroethane and 1,1-dichloroethene in atmospheric pressure air streams. The energy requirements for 90{percent} and 99{percent} decomposition of each compound are reported as a function of inlet concentration. Dichloroethene decomposition is enhanced by a chlorine radical propagated chain reaction. The chain length of the dichloroethene reaction is estimated to increase with dichloroethene concentration from 10 at 100 ppm initial dichloroethene concentration to 30 at 3000 ppm. Both the dichloroethane and dichloroethene reactions seem to be inhibited by electron scavenging decomposition products. A simple analytic expression is proposed for fitting decomposition data where inhibition effects are important and simple first order kinetics are not observed. {copyright} {ital 1997 American Institute of Physics.}

  16. Activation energy and enthalpy of decomposition for the Fe{sub 17}Sm{sub 2} nitride

    SciTech Connect (OSTI)

    Cabral, F.A.; Gama, S.; Ribeiro, C.A.

    1997-04-01

    Decomposition studies of the Fe{sub 17}Sm{sub 2}N{sub 3} compound were done using a Calvet-type microcalorimeter and a simultaneous gravimetric and differential thermal analyzer (DTA). The results show that the decomposition has onset temperature of 570{degree}C and proceeds up to 900{degree}C, and presents only one well determined exothermic thermal event. The calorimetric measurement shows that the enthalpy associated with the decomposition is 69 kJ/mol. The activation energy of the process was also determined using the Kissinger method applied to the DTA signal. It was observed that there was only one activation energy for the decomposition process, with a value of 339 kJ/mol. {copyright} {ital 1997 American Institute of Physics.}

  17. Organic and inorganic decomposition products from the thermal desorption of atmospheric particles

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

    Williams, Brent J.; Zhang, Yaping; Zuo, Xiaochen; Martinez, Raul E.; Walker, Michael J.; Kreisberg, Nathan M.; Goldstein, Allen H.; Docherty, Kenneth S.; Jimenez, Jose L.

    2016-04-11

    Here, atmospheric aerosol composition is often analyzed using thermal desorption techniques to evaporate samples and deliver organic or inorganic molecules to various designs of detectors for identification and quantification. The organic aerosol (OA) fraction is composed of thousands of individual compounds, some with nitrogen- and sulfur-containing functionality and, often contains oligomeric material, much of which may be susceptible to decomposition upon heating. Here we analyze thermal decomposition products as measured by a thermal desorption aerosol gas chromatograph (TAG) capable of separating thermal decomposition products from thermally stable molecules. The TAG impacts particles onto a collection and thermal desorption (CTD) cell, and upon completionmore » of sample collection, heats and transfers the sample in a helium flow up to 310 °C. Desorbed molecules are refocused at the head of a gas chromatography column that is held at 45 °C and any volatile decomposition products pass directly through the column and into an electron impact quadrupole mass spectrometer. Analysis of the sample introduction (thermal decomposition) period reveals contributions of NO+ (m/z 30), NO2+ (m/z 46), SO+ (m/z 48), and SO2+ (m/z 64), derived from either inorganic or organic particle-phase nitrate and sulfate. CO2+ (m/z 44) makes up a major component of the decomposition signal, along with smaller contributions from other organic components that vary with the type of aerosol contributing to the signal (e.g., m/z  53, 82 observed here for isoprene-derived secondary OA). All of these ions are important for ambient aerosol analyzed with the aerosol mass spectrometer (AMS), suggesting similarity of the thermal desorption processes in both instruments. Ambient observations of these decomposition products compared to organic, nitrate, and sulfate mass concentrations measured by an AMS reveal good correlation, with improved correlations for OA when compared to the AMS

  18. Second test of base hydrolysate decomposition in a 0.04 gallon per minute scale reactor

    SciTech Connect (OSTI)

    Cena, R.J.; Thorsness, C.B.; Coburn, T.T.; Watkins, B.E.

    1994-10-11

    LLNL has built and operated a pilot plant for processing oil shale using recirculating hot solids. This pilot plant, was adapted in 1993 to demonstrate the feasibility of decomposing base hydrolysate, a mixture of sodium nitrite, sodium formate and other constituents. This material is the waste stream from the base hydrolysis process for destruction of energetic materials. In the Livermore process, the waste feed is thermally treated in a moving packed bed of ceramic spheres, where constituents in the waste decompose, in the presence of carbon dioxide, to form solid sodium carbonate and a suite of gases including: methane, carbon monoxide, oxygen, nitrogen oxides, ammonia and possibly molecular nitrogen. The ceramic spheres are circulated and heated, providing the energy required for thermal decomposition. The spheres provide a large surface area for evaporation and decomposition to occur, avoiding sticking and agglomeration of the waste. We performed a 2.5 hour test of the solids recirculation system, with continuous injection of approximately 0.04 gal/min of waste. Gasses from the packed bed reactor were directed through the lift pipe and water was not condensed. Potassium carbonate (0.356 M) was added to the hydrolysate prior to its introduction to the retort. Continuous on-line gas analysis was invaluable in tracking the progress of the experiment and quantifying the decomposition products. Analyses showed the primary solid product, collected in the lift exit cyclone, was indeed sodium carbonate, as expected. For the reactor condition studied in this test, N{sub 2}O was found to be the primary nitrogen bearing gas species. In the test, approximately equal quantities of ammonia and nitrogen bearing oxide gases were produced. Under proper conditions, this ammonia and NO{sub x} can be recombined downstream to form N{sub 2} and O{sub 2} as the primary effluent gases.

  19. A quantitative acoustic emission study on fracture processes in ceramics based on wavelet packet decomposition

    SciTech Connect (OSTI)

    Ning, J. G.; Chu, L.; Ren, H. L.

    2014-08-28

    We base a quantitative acoustic emission (AE) study on fracture processes in alumina ceramics on wavelet packet decomposition and AE source location. According to the frequency characteristics, as well as energy and ringdown counts of AE, the fracture process is divided into four stages: crack closure, nucleation, development, and critical failure. Each of the AE signals is decomposed by a 2-level wavelet package decomposition into four different (from-low-to-high) frequency bands (AA{sub 2}, AD{sub 2}, DA{sub 2}, and DD{sub 2}). The energy eigenvalues P{sub 0}, P{sub 1}, P{sub 2}, and P{sub 3} corresponding to these four frequency bands are calculated. By analyzing changes in P{sub 0} and P{sub 3} in the four stages, we determine the inverse relationship between AE frequency and the crack source size during ceramic fracture. AE signals with regard to crack nucleation can be expressed when P{sub 0} is less than 5 and P{sub 3} more than 60; whereas AE signals with regard to dangerous crack propagation can be expressed when more than 92% of P{sub 0} is greater than 4, and more than 95% of P{sub 3} is less than 45. Geiger location algorithm is used to locate AE sources and cracks in the sample. The results of this location algorithm are consistent with the positions of fractures in the sample when observed under a scanning electronic microscope; thus the locations of fractures located with Geiger's method can reflect the fracture process. The stage division by location results is in a good agreement with the division based on AE frequency characteristics. We find that both wavelet package decomposition and Geiger's AE source locations are suitable for the identification of the evolutionary process of cracks in alumina ceramics.

  20. On the influence of the partitioning schemes on the efficiency of overlapping domain decomposition methods

    SciTech Connect (OSTI)

    Ciarlet, P. Jr.; Lamour, F.; Smith, B.F.

    1995-06-01

    One level overlapping Schwarz domain decomposition preconditioners can be viewed as a generalization of block Jacobi preconditioning. The effect of the number of blocks and the amount of overlapping between blocks on the convergence rate is well understood. This paper considers the related issue of the effect of the scheme used to partition the matrix into blocks on the convergence rate of the preconditioned iterative method. Numerical results for Laplace and linear elasticity problems in two and three dimensions are presented. The tentative conclusion is that using overlap tends to decrease the differences between the rates of convergence for different partitioning schemes.

  1. Integration of progressive hedging and dual decomposition in stochastic integer programs

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

    Watson, Jean -Paul; Guo, Ge; Hackebeil, Gabriel; Ryan, Sarah M.; Woodruff, David L.

    2015-04-07

    We present a method for integrating the Progressive Hedging (PH) algorithm and the Dual Decomposition (DD) algorithm of Carøe and Schultz for stochastic mixed-integer programs. Based on the correspondence between lower bounds obtained with PH and DD, a method to transform weights from PH to Lagrange multipliers in DD is found. Fast progress in early iterations of PH speeds up convergence of DD to an exact solution. As a result, we report computational results on server location and unit commitment instances.

  2. Effects of temperature on desiccant catalysis of refrigerant and lubricant decomposition. Final report

    SciTech Connect (OSTI)

    Rohatgi, N.D.T.

    1998-06-01

    Accelerated aging at high temperatures (149 C) for short aging times (28 days) is effective in screening the compatibility of different materials in refrigeration systems. However, in actual applications temperatures are usually lower and operating times much longer. Therefore plots to allow for interpolation or extrapolation of experimental data to actual operating conditions are needed. In the current study, aging of refrigerant/lubricant/desiccant/metal systems was conducted at five different temperatures, and for each temperature at four different aging times. The data collected from this study provided plots relating refrigerant or lubricant decomposition to aging time, aging temperature, and type of desiccant, which can be used for interpolation or extrapolation.

  3. Scenario Decomposition for 0-1 Stochastic Programs: Improvements and Asynchronous Implementation

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

    Ryan, Kevin; Rajan, Deepak; Ahmed, Shabbir

    2016-05-01

    We recently proposed scenario decomposition algorithm for stochastic 0-1 programs finds an optimal solution by evaluating and removing individual solutions that are discovered by solving scenario subproblems. In our work, we develop an asynchronous, distributed implementation of the algorithm which has computational advantages over existing synchronous implementations of the algorithm. Improvements to both the synchronous and asynchronous algorithm are proposed. We also test the results on well known stochastic 0-1 programs from the SIPLIB test library and is able to solve one previously unsolved instance from the test set.

  4. Optimal operational planning of cogeneration systems with thermal storage by the decomposition method

    SciTech Connect (OSTI)

    Yokoyama, R.; Ito, K.

    1995-12-01

    An optimal operational planning method is proposed for cogeneration systems with thermal storage. The daily operational strategy of constituent equipment is determined so as to minimize the daily operational cost subject to the energy demand requirement. This optimization problem is formulated as a large-scale mixed-integer linear programming one, and it is solved by means of the decomposition method. Effects of thermal storage on the operation of cogeneration systems are examined through a numerical study on a gas engine-driven cogeneration system installed in a hotel. This method is a useful tool for evaluating the economic and energy-saving properties of cogeneration systems with thermal storage.

  5. Combined iterative reconstruction and image-domain decomposition for dual energy CT using total-variation regularization

    SciTech Connect (OSTI)

    Dong, Xue; Niu, Tianye; Zhu, Lei

    2014-05-15

    Purpose: Dual-energy CT (DECT) is being increasingly used for its capability of material decomposition and energy-selective imaging. A generic problem of DECT, however, is that the decomposition process is unstable in the sense that the relative magnitude of decomposed signals is reduced due to signal cancellation while the image noise is accumulating from the two CT images of independent scans. Direct image decomposition, therefore, leads to severe degradation of signal-to-noise ratio on the resultant images. Existing noise suppression techniques are typically implemented in DECT with the procedures of reconstruction and decomposition performed independently, which do not explore the statistical properties of decomposed images during the reconstruction for noise reduction. In this work, the authors propose an iterative approach that combines the reconstruction and the signal decomposition procedures to minimize the DECT image noise without noticeable loss of resolution. Methods: The proposed algorithm is formulated as an optimization problem, which balances the data fidelity and total variation of decomposed images in one framework, and the decomposition step is carried out iteratively together with reconstruction. The noise in the CT images from the proposed algorithm becomes well correlated even though the noise of the raw projections is independent on the two CT scans. Due to this feature, the proposed algorithm avoids noise accumulation during the decomposition process. The authors evaluate the method performance on noise suppression and spatial resolution using phantom studies and compare the algorithm with conventional denoising approaches as well as combined iterative reconstruction methods with different forms of regularization. Results: On the Catphan600 phantom, the proposed method outperforms the existing denoising methods on preserving spatial resolution at the same level of noise suppression, i.e., a reduction of noise standard deviation by one order

  6. Monitoring the formation of carbide crystal phases during the thermal decomposition of 3d transition metal dicarboxylate complexes

    SciTech Connect (OSTI)

    Huba, ZJ; Carpenter, EE

    2014-06-06

    Single molecule precursors can help to simplify the synthesis of complex alloys by minimizing the amount of necessary starting reagents. However, single molecule precursors are time consuming to prepare with very few being commercially available. In this study, a simple precipitation method is used to prepare Fe, Co, and Ni fumarate and succinate complexes. These complexes were then thermally decomposed in an inert atmosphere to test their efficiency as single molecule precursors for the formation of metal carbide phases. Elevated temperature X-ray diffraction was used to identify the crystal phases produced upon decomposition of the metal dicarboxylate complexes. Thermogravimetric analysis coupled with an infrared detector was used to identify the developed gaseous decomposition products. All complexes tested showed a reduction from the starting M2+ oxidation state to the M oxidation state, upon decomposition. Also, each complex tested showed CO2 and H2O as gaseous decomposition products. Nickel succinate, iron succinate, and iron fumarate complexes were found to form carbide phases upon decomposition. This proves that transition metal dicarboxylate salts can be employed as efficient single molecule precursors for the formation of metal carbide crystal phases.

  7. Synthesis and in vacuo deposition of iron oxide nanoparticles by microplasma-assisted decomposition of ferrocene

    SciTech Connect (OSTI)

    Schaefer, Michael E-mail: axk650@case.edu E-mail: schlaf@mail.usf.edu; Kumar, Ajay E-mail: axk650@case.edu E-mail: schlaf@mail.usf.edu; Mohan Sankaran, R. E-mail: axk650@case.edu E-mail: schlaf@mail.usf.edu; Schlaf, Rudy E-mail: axk650@case.edu E-mail: schlaf@mail.usf.edu

    2014-10-07

    Microplasma-assisted gas-phase nucleation has emerged as an important new approach to produce high-purity, nanometer-sized, and narrowly dispersed particles. This study aims to integrate this technique with vacuum conditions to enable synthesis and deposition in an ultrahigh vacuum compatible environment. The ultimate goal is to combine nanoparticle synthesis with photoemission spectroscopy-based electronic structure analysis. Such measurements require in vacuo deposition to prevent surface contamination from sample transfer, which can be deleterious for nanoscale materials. A homebuilt microplasma reactor was integrated into an existing atomic layer deposition system attached to a surface science multi-chamber system equipped with photoemission spectroscopy. As proof-of-concept, we studied the decomposition of ferrocene vapor in the microplasma to synthesize iron oxide nanoparticles. The injection parameters were optimized to achieve complete precursor decomposition under vacuum conditions, and nanoparticles were successfully deposited. The stoichiometry of the deposited samples was characterized in situ using X-ray photoelectron spectroscopy indicating that iron oxide was formed. Additional transmission electron spectroscopy characterization allowed the determination of the size, shape, and crystal lattice of the particles, confirming their structural properties.

  8. Is the resilience of C{sub 60}{sup +} towards decomposition a question of time?

    SciTech Connect (OSTI)

    Lifshitz, C.; Sandler, P.; Gotkis, I.; Laskin, J.

    1993-12-31

    The authors have measured kinetic energy release distributions (KERDs) for the evaporation of C{sub 2} from C{sub 60}{sup +} and other fullerene cations. Through analysis of the KERDs by Klot`s theory the authors determined binding energies -- the C{sub 2} binding energy in C{sub 60}{sup +} is 5.23 eV. A thermochemical cycle gave 5.77 eV as the C{sub 2} binding energy in C{sub 60} neutral. Once these binding energies were known, it enabled calculations of time resolved breakdown curves for parent and daughter ions. These calculations included the option of energy relaxation through emission in the infra-red. It was found that C{sub 60}{sup +} is almost completely undissociated at t = 1 {mu}s at an internal energy of 30 eV. However, at t = 1s, it is completely dissociated. An intrinsic shift (IS) of 16.2 eV is predicted. These results explain SID (Surface Induced Decomposition) data by Whetten and coworkers. The applicability of Trouton`s Rule and evaporation to fullerene decompositions will be discussed. Alternative mechanisms, including the Rice {open_quotes}shrink wrap{close_quotes} mechanism, will be discussed in view of the apparent universality of the Gspann parameter, {gamma}=23.5.

  9. HYBRID SULFUR FLOWSHEETS USING PEM ELECTROLYSIS AND A BAYONET DECOMPOSITION REACTOR

    SciTech Connect (OSTI)

    Gorensek, M; William Summers, W

    2008-05-30

    A conceptual design is presented for a Hybrid Sulfur process for the production of hydrogen using a high-temperature nuclear heat source to split water. The process combines proton exchange membrane-based SO{sub 2}-depolarized electrolyzer technology being developed at Savannah River National Laboratory with silicon carbide bayonet decomposition reactor technology being developed at Sandia National Laboratories. Both are part of the US DOE Nuclear Hydrogen Initiative. The flowsheet otherwise uses only proven chemical process components. Electrolyzer product is concentrated from 50 wt% sulfuric acid to 75 wt% via recuperative vacuum distillation. Pinch analysis is used to predict the high-temperature heat requirement for sulfuric acid decomposition. An Aspen Plus{trademark} model of the flowsheet indicates 340.3 kJ high-temperature heat, 75.5 kJ low-temperature heat, 1.31 kJ low-pressure steam, and 120.9 kJ electric power are consumed per mole of H{sub 2} product, giving an LHV efficiency of 35.3% (41.7% HHV efficiency) if electric power is available at a conversion efficiency of 45%.

  10. Structural, optical and magnetic properties of gadolinium sesquioxide nanobars synthesized via thermal decomposition of gadolinium oxalate

    SciTech Connect (OSTI)

    Manigandan, R.; Giribabu, K.; Suresh, R.; Vijayalakshmi, L.; Stephen, A.; Narayanan, V.

    2013-10-15

    Graphical abstract: - Highlights: • The cubic Gd{sub 2}O{sub 3} nanobars are synthesized by decomposition of C{sub 6}H{sub 20}Gd{sub 2}O{sub 22}. • The nanoparticles are rectangular bar shape with high porous surface. • The combination of magnetic and optical properties within a single particle. • The Gd{sub 2}O{sub 3} nanobars have tailorable nanostructure, wide bandgap and are paramagnetic. - Abstract: Gadolinium oxide nanobars were obtained by thermal decomposition of gadolinium oxalate, which was synthesized by the chemical precipitation method along with glycerol. The functional group analysis and formation of gadolinium oxide from gadolinium oxalate were characterized by the Fourier transform infrared spectroscopy and thermo gravimetric analyzer. The crystal structure, average crystallite size, and lattice parameter were analyzed by X-ray diffraction technique. Moreover, Raman shifts, elemental composition and morphology of the gadolinium oxide was widely investigated by the laser Raman microscope, X-ray photoelectron spectroscopy, FE-SEM-EDAX and HR-TEM, respectively. Furthermore, the optical properties like band gap, absorbance measurement of the gadolinium oxide were extensively examined. In addition, the paramagnetic property of gadolinium oxide nanobars was explored by the vibrating sample magnetometer.

  11. METHANE HYDRATE STUDIES: DELINEATING PROPERTIES OF HOST SEDIMENTS TO ESTABLISH REPRODUCIBLE DECOMPOSITION KINETICS.

    SciTech Connect (OSTI)

    Mahajan, Devinder; Jones, Keith W.; Feng, Huan; Winters, William J.

    2004-12-01

    The use of methane hydrate as an energy source requires development of a reliable method for its extraction from its highly dispersed locations in oceanic margin sediments and permafrost. The high pressure (up to 70 MPa) and low temperature (272 K to 278 K) conditions under which hydrates are stable in the marine environment can be mimicked in a laboratory setting and several kinetic studies of pure methane hydrate decomposition have been reported. However, the effect of host sediments on methane hydrate occurrence and decomposition are required to develop reliable hydrate models. In this paper, we describe methods to measure sediment properties as they relate to pore-space methane gas hydrate. Traditional geotechnical techniques are compared to the micrometer level by use of the synchrotron Computed Microtomography (CMT) technique. CMT was used to measure the porosity at the micrometer level and to show pore-space pathways through field samples. Porosities for three sediment samples: one from a site on Georges Bank and two from the known Blake Ridge methane hydrate site, from different depths below the mud line were measured by traditional drying and by the new CMT techniques and found to be in good agreement. The integration of the two analytical approaches is necessary to enable better understanding of methane hydrate interactions with the surrounding sediment particles.

  12. Thermal Decomposition of Trinitrotoluene (TNT) with a New One-Dimensional Time to Explosion (ODTX) Apparatus

    SciTech Connect (OSTI)

    Tran, T D; Simpson, R L; Maienschein, J; Tarver, C

    2001-03-23

    The thermal explosion of trinitrotoluene (TNT) is used as a basis for evaluating the performance of a new One-Dimensional-Time-to-Explosion (ODTX) apparatus. The ODTX experiment involves holding a 12.7 mm-diameter spherical explosive sample under confinement (150 MPa) at a constant elevated temperature until the confining pressure is exceeded by the evolution of gases during chemical decomposition. The resulting time to explosion as a function of temperature provides valuable decomposition kinetic information. A comparative analysis of the measurements obtained from the new unit and an older system is presented. Discussion on selected performance aspects of the new unit will also be presented. The thermal explosion of TNT is highly dependent on the material. Analysis of the time to explosion is complicated by historical and experimental factors such as material variability, sample preparation, temperature measurement and system errors. Many of these factors will be addressed. Finally, a kinetic model using a coupled thermal and heat transport code (chemical TOPAZ) was used to match the experimental data.

  13. First-principles calculated decomposition pathways for LiBH4 nanoclusters

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

    Huang, Zhi -Quan; Chen, Wei -Chih; Chuang, Feng -Chuan; Majzoub, Eric H.; Ozolins, Vidvuds

    2016-05-18

    Here, we analyze thermodynamic stability and decomposition pathways of LiBH4 nanoclusters using grand-canonical free-energy minimization based on total energies and vibrational frequencies obtained from density-functional theory (DFT) calculations. We consider (LiBH4)n nanoclusters with n = 2 to 12 as reactants, while the possible products include (Li)n, (B)n, (LiB)n, (LiH)n, and Li2BnHn; off-stoichiometric LinBnHm (m ≤ 4n) clusters were considered for n = 2, 3, and 6. Cluster ground-state configurations have been predicted using prototype electrostatic ground-state (PEGS) and genetic algorithm (GA) based structural optimizations. Free-energy calculations show hydrogen release pathways markedly differ from those in bulk LiBH4. While experiments havemore » found that the bulk material decomposes into LiH and B, with Li2B12H12 as a kinetically inhibited intermediate phase, (LiBH4)n nanoclusters with n ≤ 12 are predicted to decompose into mixed LinBn clusters via a series of intermediate clusters of LinBnHm (m ≤ 4n). The calculated pressure-composition isotherms and temperature-pressure isobars exhibit sloping plateaus due to finite size effects on reaction thermodynamics. Generally, decomposition temperatures of free-standing clusters are found to increase with decreasing cluster size due to thermodynamic destabilization of reaction products.« less

  14. Theoretical Study of the Thermal Decomposition of Carboxylic Acids at Pyrolysis Temperature

    SciTech Connect (OSTI)

    Clark, J. M.; Robichaud, D. J.; Nimlos, M. R.

    2013-01-01

    Carboxylic acids are important in the processing of biomass into renewable fuels and chemicals. They are formed from the pretreatment and pyrolysis of hemicellulose biopolymers and are released from the decomposition of sugars. They result from the deconstruction of polyhydroxyalkanoates (bacterial carbon storage polymers) from fatty acids derived from algae, bacteria, and oil crops. The thermal deoxygenation of carboxylic acids is an important step in the conversion of biomass into aliphatic hydrocarbons suitable for use in renewable biofuels and as petrochemical replacements. Decarboxylation, a primary decomposition pathway under pyrolysis conditions, represents an ideal conversion process, because it eliminates two atoms of oxygen for every carbon atom removed. Problematically, additional deoxygenation processes exist (e.g. dehydration) that are in direct competition with decarboxylation and result in the formation of reactive and more fragmented end products. To better understand the competition between decarboxylation and other deoxygenation processes and to gain insight into possible catalysts that would favor decarboxylation, we have investigated the mechanisms and thermochemistry of the various unimolecular and bimolecular deoxygenation pathways for a family of C1-C4 organic acids using electronic structure calculations at the M06-2X/6-311++G(2df,p) level of theory.

  15. Trends in Methanol Decomposition on Transition Metal Alloy Clusters from Scaling and BrnstedEvansPolanyi Relationships

    SciTech Connect (OSTI)

    Mehmood, Faisal; Rankin, Rees B.; Greeley, Jeffrey P.; Curtiss, Larry A.

    2012-05-15

    A combination of ?rst principles Density Functional Theory calculations and thermochemical scaling relationships are employed to estimate the thermochemistry and kinetics of methanol decomposition on unsupported subnanometer metal clusters. The approach uses binding energies of various atomic and molecular species, determined on the pure metal clusters, to develop scaling relationships that are then further used to estimate the methanol decomposition thermodynamics for a series of pure and bimetallic clusters with four atoms per cluster. Additionally, activation energy barriers are estimated from BrnstedEvansPolanyi plots relating transition and ?nal state energies on these clusters. The energetic results are combined with a simple, microkineticallyinspired rate expression to estimate reaction rates as a function of important catalytic descriptors, including the carbon and atomic oxygen binding energies to the clusters. Based on these analyses, several alloy clusters are identi?ed as promising candidates for the methanol decomposition reaction.

  16. The application of domain decomposition to time-domain computations of nonlinear water waves with a panel method

    SciTech Connect (OSTI)

    De Haas, P.C.A.; Zandbergen, P.J.

    1996-12-01

    In this paper an iterative domain decomposition method for the solution of Laplace`s equation is described and its effectiveness in time-domain computations of nonlinear water waves with a panel method is investigated. An important aspect of these computations is the varying shape of the free surface. The convergence of the iterative method is fast and leads to a speedup of the computations in the aforementioned application. The domain decomposition method gives a considerable reduction of memory requirements. Furthermore, it lends itself naturally for parallel computing. 18 refs., 9 figs., 2 tabs.

  17. Hybrid and Parallel Domain-Decomposition Methods Development to Enable Monte Carlo for Reactor Analyses

    SciTech Connect (OSTI)

    Wagner, John C; Mosher, Scott W; Evans, Thomas M; Peplow, Douglas E.; Turner, John A

    2011-01-01

    This paper describes code and methods development at the Oak Ridge National Laboratory focused on enabling high-fidelity, large-scale reactor analyses with Monte Carlo (MC). Current state-of-the-art tools and methods used to perform real commercial reactor analyses have several undesirable features, the most significant of which is the non-rigorous spatial decomposition scheme. Monte Carlo methods, which allow detailed and accurate modeling of the full geometry and are considered the gold standard for radiation transport solutions, are playing an ever-increasing role in correcting and/or verifying the deterministic, multi-level spatial decomposition methodology in current practice. However, the prohibitive computational requirements associated with obtaining fully converged, system-wide solutions restrict the role of MC to benchmarking deterministic results at a limited number of state-points for a limited number of relevant quantities. The goal of this research is to change this paradigm by enabling direct use of MC for full-core reactor analyses. The most significant of the many technical challenges that must be overcome are the slow, non-uniform convergence of system-wide MC estimates and the memory requirements associated with detailed solutions throughout a reactor (problems involving hundreds of millions of different material and tally regions due to fuel irradiation, temperature distributions, and the needs associated with multi-physics code coupling). To address these challenges, our research has focused on the development and implementation of (1) a novel hybrid deterministic/MC method for determining high-precision fluxes throughout the problem space in k-eigenvalue problems and (2) an efficient MC domain-decomposition (DD) algorithm that partitions the problem phase space onto multiple processors for massively parallel systems, with statistical uncertainty estimation. The hybrid method development is based on an extension of the FW-CADIS method, which

  18. Hybrid and Parallel Domain-Decomposition Methods Development to Enable Monte Carlo for Reactor Analyses

    SciTech Connect (OSTI)

    Wagner, John C; Mosher, Scott W; Evans, Thomas M; Peplow, Douglas E.; Turner, John A

    2010-01-01

    This paper describes code and methods development at the Oak Ridge National Laboratory focused on enabling high-fidelity, large-scale reactor analyses with Monte Carlo (MC). Current state-of-the-art tools and methods used to perform ''real'' commercial reactor analyses have several undesirable features, the most significant of which is the non-rigorous spatial decomposition scheme. Monte Carlo methods, which allow detailed and accurate modeling of the full geometry and are considered the ''gold standard'' for radiation transport solutions, are playing an ever-increasing role in correcting and/or verifying the deterministic, multi-level spatial decomposition methodology in current practice. However, the prohibitive computational requirements associated with obtaining fully converged, system-wide solutions restrict the role of MC to benchmarking deterministic results at a limited number of state-points for a limited number of relevant quantities. The goal of this research is to change this paradigm by enabling direct use of MC for full-core reactor analyses. The most significant of the many technical challenges that must be overcome are the slow, non-uniform convergence of system-wide MC estimates and the memory requirements associated with detailed solutions throughout a reactor (problems involving hundreds of millions of different material and tally regions due to fuel irradiation, temperature distributions, and the needs associated with multi-physics code coupling). To address these challenges, our research has focused on the development and implementation of (1) a novel hybrid deterministic/MC method for determining high-precision fluxes throughout the problem space in k-eigenvalue problems and (2) an efficient MC domain-decomposition (DD) algorithm that partitions the problem phase space onto multiple processors for massively parallel systems, with statistical uncertainty estimation. The hybrid method development is based on an extension of the FW-CADIS method

  19. Optimization-based additive decomposition of weakly coercive problems with applications

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

    Bochev, Pavel B.; Ridzal, Denis

    2016-01-27

    In this study, we present an abstract mathematical framework for an optimization-based additive decomposition of a large class of variational problems into a collection of concurrent subproblems. The framework replaces a given monolithic problem by an equivalent constrained optimization formulation in which the subproblems define the optimization constraints and the objective is to minimize the mismatch between their solutions. The significance of this reformulation stems from the fact that one can solve the resulting optimality system by an iterative process involving only solutions of the subproblems. Consequently, assuming that stable numerical methods and efficient solvers are available for every subproblem,more » our reformulation leads to robust and efficient numerical algorithms for a given monolithic problem by breaking it into subproblems that can be handled more easily. An application of the framework to the Oseen equations illustrates its potential.« less

  20. FETI Prime Domain Decomposition base Parallel Iterative Solver Library Ver.1.0

    Energy Science and Technology Software Center (OSTI)

    2003-09-15

    FETI Prime is a library for the iterative solution of linear equations in solid and structural mechanics. The algorithm employs preconditioned conjugate gradients, with a domain decomposition-based preconditioner. The software is written in C++ and is designed for use with massively parallel computers, using MPI. The algorithm is based on the FETI-DP method, with additional capabilities for handling constraint equations, as well as interfacing with the Salinas structural dynamics code and the Finite Element Interfacemore » (FEI) library. Practical Application: FETI Prime is designed for use with finite element-based simulation codes for solid and structural mechanics. The solver uses element matrices, connectivity information, nodal information, and force vectors computed by the host code and provides back the solution to the linear system of equations, to the user specified level of accuracy, The library is compiled with the host code and becomes an integral part of the host code executable.« less

  1. Method for hydroperoxide decomposition using novel porphyrins synthesized from dipyrromethanes and aldehydes

    DOE Patents [OSTI]

    Wijesekera, Tilak; Lyons, James E.; Ellis, Jr., Paul E.

    1998-01-01

    The invention comprises a method for the oxidation of alkanes to alcohols and for decomposition of hydroperoxides to alcohols utilizing new compositions of matter, which are metal complexes of porphyrins. Preferred complexes have hydrogen, haloalkyl or haloaryl groups in meso positions, two of the opposed meso atoms or groups being hydrogen or haloaryl, and two of the opposed meso atoms or groups being hydrogen or haloalkyl, but not all four of the meso atoms or groups being hydrogen. Other preferred complexes are ones in which all four of the meso positions are substituted with haloalkyl groups and the beta positions are substituted with halogen atoms. A new method of synthesizing porphyrinogens is also disclosed.

  2. Method for hydroperoxide decomposition using novel porphyrins synthesized from dipyrromethanes and aldehydes

    DOE Patents [OSTI]

    Wijesekera, T.; Lyons, J.E.; Ellis, P.E. Jr.

    1998-03-03

    The invention comprises a method for the oxidation of alkanes to alcohols and for decomposition of hydroperoxides to alcohols utilizing new compositions of matter, which are metal complexes of porphyrins. Preferred complexes have hydrogen, haloalkyl or haloaryl groups in meso positions, two of the opposed meso atoms or groups being hydrogen or haloaryl, and two of the opposed meso atoms or groups being hydrogen or haloalkyl, but not all four of the meso atoms or groups being hydrogen. Other preferred complexes are ones in which all four of the meso positions are substituted with haloalkyl groups and the beta positions are substituted with halogen atoms. A new method of synthesizing porphyrinogens is also disclosed.

  3. Sapphire decomposition and inversion domains in N-polar aluminum nitride

    SciTech Connect (OSTI)

    Hussey, Lindsay White, Ryan M.; Kirste, Ronny; Bryan, Isaac; Guo, Wei; Osterman, Katherine; Haidet, Brian; Bryan, Zachary; Bobea, Milena; Collazo, Ramn; Sitar, Zlatko; Mita, Seiji

    2014-01-20

    Transmission electron microscopy (TEM) techniques and potassium hydroxide (KOH) etching confirmed that inversion domains in the N-polar AlN grown on c-plane sapphire were due to the decomposition of sapphire in the presence of hydrogen. The inversion domains were found to correspond to voids at the AlN and sapphire interface, and transmission electron microscopy results showed a V-shaped, columnar inversion domain with staggered domain boundary sidewalls. Voids were also observed in the simultaneously grown Al-polar AlN, however no inversion domains were present. The polarity of AlN grown above the decomposed regions of the sapphire substrate was confirmed to be Al-polar by KOH etching and TEM.

  4. An Algorithm for Decomposition of the Charged Particle Scattering Cross Sections into Singular and Regular Components

    SciTech Connect (OSTI)

    Inanc, Feyzi

    2005-04-09

    Any radiography simulation effort that involves high energy photons should also address charged particle transport problem as well. The scattering cross sections with the charged particles, namely electrons and positrons, go through elastic and inelastic scattering interactions that are highly anisotropic. The conventional Boltzmann operator used in the transport computations can not represent the highly anisotropic scattering interactions. One way is to implement Fokker-Planck operators. The implementation of Fokker-Planck operators requires decomposition of scattering kernels into singular and regular components. This paper introduces an algorithm on how to decompose the elastic and inelastic scattering cross sections into singular and regular components and how to compute momentum transfer and stopping power coefficients from singular components.

  5. Validation of Heat Transfer Thermal Decomposition and Container Pressurization of Polyurethane Foam.

    SciTech Connect (OSTI)

    Scott, Sarah Nicole; Dodd, Amanda B.; Larsen, Marvin E.; Suo-Anttila, Jill M.; Erickson, Kenneth L

    2014-09-01

    Polymer foam encapsulants provide mechanical, electrical, and thermal isolation in engineered systems. In fire environments, gas pressure from thermal decomposition of polymers can cause mechanical failure of sealed systems. In this work, a detailed uncertainty quantification study of PMDI-based polyurethane foam is presented to assess the validity of the computational model. Both experimental measurement uncertainty and model prediction uncertainty are examined and compared. Both the mean value method and Latin hypercube sampling approach are used to propagate the uncertainty through the model. In addition to comparing computational and experimental results, the importance of each input parameter on the simulation result is also investigated. These results show that further development in the physics model of the foam and appropriate associated material testing are necessary to improve model accuracy.

  6. Final Report, DE-FG01-06ER25718 Domain Decomposition and Parallel Computing

    SciTech Connect (OSTI)

    Widlund, Olof B.

    2015-06-09

    The goal of this project is to develop and improve domain decomposition algorithms for a variety of partial differential equations such as those of linear elasticity and electro-magnetics.These iterative methods are designed for massively parallel computing systems and allow the fast solution of the very large systems of algebraic equations that arise in large scale and complicated simulations. A special emphasis is placed on problems arising from Maxwell's equation. The approximate solvers, the preconditioners, are combined with the conjugate gradient method and must always include a solver of a coarse model in order to have a performance which is independent of the number of processors used in the computer simulation. A recent development allows for an adaptive construction of this coarse component of the preconditioner.

  7. Growth and stability of oxidation resistant Si nanocrystals formed by decomposition of alkyl silanes

    SciTech Connect (OSTI)

    Zaitseva, N; Hamel, S; Dai, Z R; Saw, C; Williamson, A J; Galli, G

    2007-01-12

    The synthesis and characterization of 1-10 nm Si nanocrystals highly resistant to oxidation is described. The nanocrystals were prepared by thermal decomposition of tetramethylsilane at 680 C, or in a gold- induced catalytic process at lower temperatures down to 400-450 C using trioctylamine as an initial solvent. Transmission electron microscopic analysis of samples obtained in the presence of gold show that the nanocrystals form via solid-phase epitaxial attachment of Si to the gold crystal lattice. The results of computational modeling performed using first principles density functional theory (DFT) calculations predict that the enhanced stability of nanocrystals to oxidation is due to the presence of N or N-containing groups on the surface of nanocrystals.

  8. Low-rank matrix decomposition and spatio-temporal sparse recovery for STAP radar

    SciTech Connect (OSTI)

    Sen, Satyabrata

    2015-08-04

    We develop space-time adaptive processing (STAP) methods by leveraging the advantages of sparse signal processing techniques in order to detect a slowly-moving target. We observe that the inherent sparse characteristics of a STAP problem can be formulated as the low-rankness of clutter covariance matrix when compared to the total adaptive degrees-of-freedom, and also as the sparse interference spectrum on the spatio-temporal domain. By exploiting these sparse properties, we propose two approaches for estimating the interference covariance matrix. In the first approach, we consider a constrained matrix rank minimization problem (RMP) to decompose the sample covariance matrix into a low-rank positive semidefinite and a diagonal matrix. The solution of RMP is obtained by applying the trace minimization technique and the singular value decomposition with matrix shrinkage operator. Our second approach deals with the atomic norm minimization problem to recover the clutter response-vector that has a sparse support on the spatio-temporal plane. We use convex relaxation based standard sparse-recovery techniques to find the solutions. With extensive numerical examples, we demonstrate the performances of proposed STAP approaches with respect to both the ideal and practical scenarios, involving Doppler-ambiguous clutter ridges, spatial and temporal decorrelation effects. As a result, the low-rank matrix decomposition based solution requires secondary measurements as many as twice the clutter rank to attain a near-ideal STAP performance; whereas the spatio-temporal sparsity based approach needs a considerably small number of secondary data.

  9. Low-rank matrix decomposition and spatio-temporal sparse recovery for STAP radar

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

    Sen, Satyabrata

    2015-08-04

    We develop space-time adaptive processing (STAP) methods by leveraging the advantages of sparse signal processing techniques in order to detect a slowly-moving target. We observe that the inherent sparse characteristics of a STAP problem can be formulated as the low-rankness of clutter covariance matrix when compared to the total adaptive degrees-of-freedom, and also as the sparse interference spectrum on the spatio-temporal domain. By exploiting these sparse properties, we propose two approaches for estimating the interference covariance matrix. In the first approach, we consider a constrained matrix rank minimization problem (RMP) to decompose the sample covariance matrix into a low-rank positivemore » semidefinite and a diagonal matrix. The solution of RMP is obtained by applying the trace minimization technique and the singular value decomposition with matrix shrinkage operator. Our second approach deals with the atomic norm minimization problem to recover the clutter response-vector that has a sparse support on the spatio-temporal plane. We use convex relaxation based standard sparse-recovery techniques to find the solutions. With extensive numerical examples, we demonstrate the performances of proposed STAP approaches with respect to both the ideal and practical scenarios, involving Doppler-ambiguous clutter ridges, spatial and temporal decorrelation effects. As a result, the low-rank matrix decomposition based solution requires secondary measurements as many as twice the clutter rank to attain a near-ideal STAP performance; whereas the spatio-temporal sparsity based approach needs a considerably small number of secondary data.« less

  10. Decomposition of the scattering amplitude into shadow and surface components with inclusion of spin-orbit coupling

    SciTech Connect (OSTI)

    Melo, German; David, Jorge; Restrepo, Albeiro

    2008-09-15

    We propose a decomposition of the scattering amplitude into shadow and surface components for proton scattering against calcium isotopes as targets at 21 MeV. We account for spin-orbit coupling effects for the optical potential in the nonrelativistic limit. Our calculations show very good agreement with experimental trends.

  11. Simulation of toluene decomposition in a pulse-periodic discharge operating in a mixture of molecular nitrogen and oxygen

    SciTech Connect (OSTI)

    Trushkin, A. N.; Kochetov, I. V.

    2012-05-15

    The kinetic model of toluene decomposition in nonequilibrium low-temperature plasma generated by a pulse-periodic discharge operating in a mixture of nitrogen and oxygen is developed. The results of numerical simulation of plasma-chemical conversion of toluene are presented; the main processes responsible for C{sub 6}H{sub 5}CH{sub 3} decomposition are identified; the contribution of each process to total removal of toluene is determined; and the intermediate and final products of C{sub 6}H{sub 5}CH{sub 3} decomposition are identified. It was shown that toluene in pure nitrogen is mostly decomposed in its reactions with metastable N{sub 2}(A{sub 3}{Sigma}{sub u}{sup +}) and N{sub 2}(a Prime {sup 1}{Sigma}{sub u}{sup -}) molecules. In the presence of oxygen, in the N{sub 2} : O{sub 2} gas mixture, the largest contribution to C{sub 6}H{sub 5}CH{sub 3} removal is made by the hydroxyl radical OH which is generated in this mixture exclusively due to plasma-chemical reactions between toluene and oxygen decomposition products. Numerical simulation showed the existence of an optimum oxygen concentration in the mixture, at which toluene removal is maximum at a fixed energy deposition.

  12. New bounding and decomposition approaches for MILP investment problems: Multi-area transmission and generation planning under policy constraints

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

    Munoz, F. D.; Hobbs, B. F.; Watson, J. -P.

    2016-02-01

    A novel two-phase bounding and decomposition approach to compute optimal and near-optimal solutions to large-scale mixed-integer investment planning problems is proposed and it considers a large number of operating subproblems, each of which is a convex optimization. Our motivating application is the planning of power transmission and generation in which policy constraints are designed to incentivize high amounts of intermittent generation in electric power systems. The bounding phase exploits Jensen’s inequality to define a lower bound, which we extend to stochastic programs that use expected-value constraints to enforce policy objectives. The decomposition phase, in which the bounds are tightened, improvesmore » upon the standard Benders’ algorithm by accelerating the convergence of the bounds. The lower bound is tightened by using a Jensen’s inequality-based approach to introduce an auxiliary lower bound into the Benders master problem. Upper bounds for both phases are computed using a sub-sampling approach executed on a parallel computer system. Numerical results show that only the bounding phase is necessary if loose optimality gaps are acceptable. But, the decomposition phase is required to attain optimality gaps. Moreover, use of both phases performs better, in terms of convergence speed, than attempting to solve the problem using just the bounding phase or regular Benders decomposition separately.« less

  13. Thermal Decomposition Characteristics of Orthorhombic Ammonium Perchlorate (o-AP) and an 0-AP/HTPB-Based Propellant

    SciTech Connect (OSTI)

    BEHRENS JR.,RICHARD; MINIER,LEANNA M.G.

    1999-10-25

    A study to characterize the low-temperature reactive processes for o-AP and an AP/HTPB-based propellant (class 1.3) is being conducted in the laboratory using the techniques of simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) and scanning electron microscopy (SEM). The results presented in this paper are a follow up of the previous work that showed the overall decomposition to be complex and controlled by both physical and chemical processes. The decomposition is characterized by the occurrence of one major event that consumes up to {approx}35% of the AP, depending upon particle size, and leaves behind a porous agglomerate of AP. The major gaseous products released during this event include H{sub 2}O, O{sub 2}, Cl{sub 2}, N{sub 2}O and HCl. The recent efforts provide further insight into the decomposition processes for o-AP. The temporal behaviors of the gas formation rates (GFRs) for the products indicate that the major decomposition event consists of three chemical channels. The first and third channels are affected by the pressure in the reaction cell and occur at the surface or in the gas phase above the surface of the AP particles. The second channel is not affected by pressure and accounts for the solid-phase reactions characteristic of o-AP. The third channel involves the interactions of the decomposition products with the surface of the AP. SEM images of partially decomposed o-AP provide insight to how the morphology changes as the decomposition progresses. A conceptual model has been developed, based upon the STMBMS and SEM results, that provides a basic description of the processes. The thermal decomposition characteristics of the propellant are evaluated from the identities of the products and the temporal behaviors of their GFRs. First, the volatile components in the propellant evolve from the propellant as it is heated. Second, the hot AP (and HClO{sub 4}) at the AP-binder interface oxidize the binder through reactions that

  14. Unveiling the proton spin decomposition at a future electron-ion collider

    SciTech Connect (OSTI)

    Aschenauer, Elke C.; Sassot, Rodolfo; Stratmann, Marco

    2015-11-24

    We present a detailed assessment of how well a future electron-ion collider could constrain helicity parton distributions in the nucleon and, therefore, unveil the role of the intrinsic spin of quarks and gluons in the proton’s spin budget. Any remaining deficit in this decomposition will provide the best indirect constraint on the contribution due to the total orbital angular momenta of quarks and gluons. Specifically, all our studies are performed in the context of global QCD analyses based on realistic pseudodata and in the light of the most recent data obtained from polarized proton-proton collisions at BNL-RHIC that have provided evidence for a significant gluon polarization in the accessible, albeit limited range of momentum fractions. We also present projections on what can be achieved on the gluon’s helicity distribution by the end of BNL-RHIC operations. As a result, all estimates of current and projected uncertainties are performed with the robust Lagrange multiplier technique.

  15. Direct numerical simulation of shear localization and decomposition reactions in shock-loaded HMX crystal

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

    Austin, Ryan A.; Barton, Nathan R.; Reaugh, John E.; Fried, Laurence E.

    2015-05-14

    A numerical model is developed to study the shock wave ignition of HMX crystal. The model accounts for the coupling between crystal thermal/mechanical responses and chemical reactions that are driven by the temperature field. This allows for the direct numerical simulation of decomposition reactions in the hot spots formed by shock/impact loading. The model is used to simulate intragranular pore collapse under shock wave loading. In a reference case: (i) shear-enabled micro-jetting is responsible for a modest extent of reaction in the pore collapse region, and (ii) shear banding is found to be an important mode of localization. The shearmore » bands, which are filled with molten HMX, grow out of the pore collapse region and serve as potential ignition sites. The model predictions of shear banding and reactivity are found to be quite sensitive to the respective flow strengths of the solid and liquid phases. In this regard, it is shown that reasonable assumptions of liquid-HMX viscosity can lead to chemical reactions within the shear bands on a nanosecond time scale.« less

  16. Unveiling the proton spin decomposition at a future electron-ion collider

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

    Aschenauer, Elke C.; Sassot, Rodolfo; Stratmann, Marco

    2015-11-24

    We present a detailed assessment of how well a future electron-ion collider could constrain helicity parton distributions in the nucleon and, therefore, unveil the role of the intrinsic spin of quarks and gluons in the proton’s spin budget. Any remaining deficit in this decomposition will provide the best indirect constraint on the contribution due to the total orbital angular momenta of quarks and gluons. Specifically, all our studies are performed in the context of global QCD analyses based on realistic pseudodata and in the light of the most recent data obtained from polarized proton-proton collisions at BNL-RHIC that have providedmore » evidence for a significant gluon polarization in the accessible, albeit limited range of momentum fractions. We also present projections on what can be achieved on the gluon’s helicity distribution by the end of BNL-RHIC operations. As a result, all estimates of current and projected uncertainties are performed with the robust Lagrange multiplier technique.« less

  17. Demonstration of base catalyzed decomposition process, Navy Public Works Center, Guam, Mariana Islands

    SciTech Connect (OSTI)

    Schmidt, A.J.; Freeman, H.D.; Brown, M.D.; Zacher, A.H.; Neuenschwander, G.N.; Wilcox, W.A.; Gano, S.R.; Kim, B.C.; Gavaskar, A.R.

    1996-02-01

    Base Catalyzed Decomposition (BCD) is a chemical dehalogenation process designed for treating soils and other substrate contaminated with polychlorinated biphenyls (PCB), pesticides, dioxins, furans, and other hazardous organic substances. PCBs are heavy organic liquids once widely used in industry as lubricants, heat transfer oils, and transformer dielectric fluids. In 1976, production was banned when PCBs were recognized as carcinogenic substances. It was estimated that significant quantities (one billion tons) of U.S. soils, including areas on U.S. military bases outside the country, were contaminated by PCB leaks and spills, and cleanup activities began. The BCD technology was developed in response to these activities. This report details the evolution of the process, from inception to deployment in Guam, and describes the process and system components provided to the Navy to meet the remediation requirements. The report is divided into several sections to cover the range of development and demonstration activities. Section 2.0 gives an overview of the project history. Section 3.0 describes the process chemistry and remediation steps involved. Section 4.0 provides a detailed description of each component and specific development activities. Section 5.0 details the testing and deployment operations and provides the results of the individual demonstration campaigns. Section 6.0 gives an economic assessment of the process. Section 7.0 presents the conclusions and recommendations form this project. The appendices contain equipment and instrument lists, equipment drawings, and detailed run and analytical data.

  18. Synthesis of phase-pure and monodisperse iron oxide nanoparticles by thermal decomposition

    SciTech Connect (OSTI)

    Hufschmid, Ryan D.; Arami, Hamed; Ferguson, R. Matthew; Gonzales, Marcela; Teeman, Eric M.; Brush, Lucien N.; Browning, Nigel D.; Krishnan, Kannan M.

    2015-06-03

    We present a comprehensive template for the design and synthesis of iron oxide nanoparticles with control over size, size distribution, phase, and resulting properties. Monodisperse superparamagnetic iron oxide nanoparticles were synthesized by thermal decomposition of three different iron containing precursors (iron oleate, iron pentacarbonyl, and iron oxyhydroxide) in organic solvents under a variety of synthetic conditions. We compare the suitability of these three kinetically controlled synthesis protocols, which have in common the use of iron oleate as a starting precursor or reaction intermediate, for producing nanoparticles with specific size and magnetic properties. Monodisperse particles were produced over a tunable range of sizes from approximately 2-30 nm. Reaction parameters such as precursor concentration, addition of surfactant, temperature, ramp rate, and time were adjusted to kinetically control size and size-distribution. In particular, large quantities of excess surfactant (up to 25:1 molar ratio) alter reaction kinetics and result in larger particles with uniform size; however, there is often a trade-off between large particles and a narrow size distribution. Iron oxide phase is also critical for establishing magnetic properties. As an example, we show the importance of obtaining the required iron oxide phase for application to Magnetic Particle Imaging (MPI), and describe how phase purity can be controlled.

  19. Reactive power planning under high penetration of wind energy using Benders decomposition

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

    Xu, Yan; Wei, Yanli; Fang, Xin; Li, Fangxing; Azim, Riyasat

    2015-11-05

    This study addresses the optimal allocation of reactive power volt-ampere reactive (VAR) sources under the paradigm of high penetration of wind energy. Reactive power planning (RPP) in this particular condition involves a high level of uncertainty because of wind power characteristic. To properly model wind generation uncertainty, a multi-scenario framework optimal power flow that considers the voltage stability constraint under the worst wind scenario and transmission N 1 contingency is developed. The objective of RPP in this study is to minimise the total cost including the VAR investment cost and the expected generation cost. Therefore RPP under this condition ismore » modelled as a two-stage stochastic programming problem to optimise the VAR location and size in one stage, then to minimise the fuel cost in the other stage, and eventually, to find the global optimal RPP results iteratively. Benders decomposition is used to solve this model with an upper level problem (master problem) for VAR allocation optimisation and a lower problem (sub-problem) for generation cost minimisation. Impact of the potential reactive power support from doubly-fed induction generator (DFIG) is also analysed. Lastly, case studies on the IEEE 14-bus and 118-bus systems are provided to verify the proposed method.« less

  20. Orthogonal decomposition as a design tool: With application to a mixing impeller

    SciTech Connect (OSTI)

    Sloan, Benjamin

    2013-05-15

    Digital manufacturing eliminates the expense and time required to develop custom products. By utilizing this technology, designers can quickly create a customized product specifically for their performance needs. But the timescale and expense from the engineering design workflows used to develop these customized products have not been adapted from the workflows used in mass production. In many cases these customized designs build upon already successful mass-produced products that were developed using conventional engineering design workflows. Many times as part of this conventional design process significant time is spent creating and validating high fidelity models that accurately predict the performance of the final design. These existing validated high fidelity models used for the mass-produced design can be reused for analysis and design of unknown products. This thesis explores the integration of reduced order modeling and detailed analysis into the engineering design workflow developing a customized design using digital manufacturing. Specifically, detailed analysis is coupled with proper orthogonal decomposition to enable the exploration of the design space while simultaneously shaping the model representing the design. This revised workflow is examined using the design of a laboratory scale overhead mixer impeller. The case study presented here is compared with the design of the Kar Dynamic Mixer impeller developed by The Dow Chemical Company. The result of which is a customized design for a refined set of operating conditions with improved performance.

  1. Balancing Conflicting Requirements for Grid and Particle Decomposition in Continuum-Lagrangian Solvers

    SciTech Connect (OSTI)

    Sitaraman, Hariswaran; Grout, Ray

    2015-10-30

    The load balancing strategies for hybrid solvers that involve grid based partial differential equation solution coupled with particle tracking are presented in this paper. A typical Message Passing Interface (MPI) based parallelization of grid based solves are done using a spatial domain decomposition while particle tracking is primarily done using either of the two techniques. One of the techniques is to distribute the particles to MPI ranks to whose grid they belong to while the other is to share the particles equally among all ranks, irrespective of their spatial location. The former technique provides spatial locality for field interpolation but cannot assure load balance in terms of number of particles, which is achieved by the latter. The two techniques are compared for a case of particle tracking in a homogeneous isotropic turbulence box as well as a turbulent jet case. We performed a strong scaling study for more than 32,000 cores, which results in particle densities representative of anticipated exascale machines. The use of alternative implementations of MPI collectives and efficient load equalization strategies are studied to reduce data communication overheads.

  2. Reactive power planning under high penetration of wind energy using Benders decomposition

    SciTech Connect (OSTI)

    Xu, Yan; Wei, Yanli; Fang, Xin; Li, Fangxing; Azim, Riyasat

    2015-11-05

    This study addresses the optimal allocation of reactive power volt-ampere reactive (VAR) sources under the paradigm of high penetration of wind energy. Reactive power planning (RPP) in this particular condition involves a high level of uncertainty because of wind power characteristic. To properly model wind generation uncertainty, a multi-scenario framework optimal power flow that considers the voltage stability constraint under the worst wind scenario and transmission N 1 contingency is developed. The objective of RPP in this study is to minimise the total cost including the VAR investment cost and the expected generation cost. Therefore RPP under this condition is modelled as a two-stage stochastic programming problem to optimise the VAR location and size in one stage, then to minimise the fuel cost in the other stage, and eventually, to find the global optimal RPP results iteratively. Benders decomposition is used to solve this model with an upper level problem (master problem) for VAR allocation optimisation and a lower problem (sub-problem) for generation cost minimisation. Impact of the potential reactive power support from doubly-fed induction generator (DFIG) is also analysed. Lastly, case studies on the IEEE 14-bus and 118-bus systems are provided to verify the proposed method.

  3. Direct numerical simulation of shear localization and decomposition reactions in shock-loaded HMX crystal

    SciTech Connect (OSTI)

    Austin, Ryan A.; Barton, Nathan R.; Reaugh, John E.; Fried, Laurence E.

    2015-05-14

    A numerical model is developed to study the shock wave ignition of HMX crystal. The model accounts for the coupling between crystal thermal/mechanical responses and chemical reactions that are driven by the temperature field. This allows for the direct numerical simulation of decomposition reactions in the hot spots formed by shock/impact loading. The model is used to simulate intragranular pore collapse under shock wave loading. In a reference case: (i) shear-enabled micro-jetting is responsible for a modest extent of reaction in the pore collapse region, and (ii) shear banding is found to be an important mode of localization. The shear bands, which are filled with molten HMX, grow out of the pore collapse region and serve as potential ignition sites. The model predictions of shear banding and reactivity are found to be quite sensitive to the respective flow strengths of the solid and liquid phases. In this regard, it is shown that reasonable assumptions of liquid-HMX viscosity can lead to chemical reactions within the shear bands on a nanosecond time scale.

  4. Molecular Theory of Detonation Initiation: Insight from First Principles Modeling of the Decomposition Mechanisms of Organic Nitro Energetic Materials

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

    Tsyshevsky, Roman; Sharia, Onise; Kuklja, Maija

    2016-02-19

    Our review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation initiation theory in a widely agreed upon form. However, recent advances in experimental and theoretical methods allow for a constructive and rigorous approach to design and test the theory or at least some of its fundamental building blocks. In this review, we analyzed a set of select experimental and theoretical articles, which were augmented by our ownmore » first principles modeling and simulations, to reveal new trends in energetic materials and to refine known existing correlations between their structures, properties, and functions. Lastly, our consideration is intentionally limited to the processes of thermally stimulated chemical reactions at the earliest stage of decomposition of molecules and materials containing defects.« less

  5. Time-dependent density functional theory for open systems with a positivity-preserving decomposition scheme for environment spectral functions

    SciTech Connect (OSTI)

    Wang, RuLin; Zheng, Xiao; Kwok, YanHo; Xie, Hang; Chen, GuanHua; Yam, ChiYung

    2015-04-14

    Understanding electronic dynamics on material surfaces is fundamentally important for applications including nanoelectronics, inhomogeneous catalysis, and photovoltaics. Practical approaches based on time-dependent density functional theory for open systems have been developed to characterize the dissipative dynamics of electrons in bulk materials. The accuracy and reliability of such approaches depend critically on how the electronic structure and memory effects of surrounding material environment are accounted for. In this work, we develop a novel squared-Lorentzian decomposition scheme, which preserves the positive semi-definiteness of the environment spectral matrix. The resulting electronic dynamics is guaranteed to be both accurate and convergent even in the long-time limit. The long-time stability of electronic dynamics simulation is thus greatly improved within the current decomposition scheme. The validity and usefulness of our new approach are exemplified via two prototypical model systems: quasi-one-dimensional atomic chains and two-dimensional bilayer graphene.

  6. A comparative density functional study of methanol decomposition on Cu{sub 4} and Co{sub 4} clusters.

    SciTech Connect (OSTI)

    Mehmood, F.; Greeley, J.; Zapol, P.; Curtiss, L. A.

    2010-08-12

    A density functional theory study of the decomposition of methanol on Cu{sub 4} and Co{sub 4} clusters is presented. The reaction intermediates and activation barriers have been determined for reaction steps to form H{sub 2} and CO. For both clusters, methanol decomposition initiated by C-H and O-H bond breaking was investigated. In the case of a Cu{sub 4} cluster, methanol dehydrogenation through hydroxymethyl (CH{sub 2}OH), hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO) is found to be slightly more favorable. For a Co{sub 4} cluster, the dehydrogenation pathway through methoxy (CH{sub 3}O) and formaldehyde (CH{sub 2}O) is slightly more favorable. Each of these pathways results in formation of CO and H{sub 2}. The Co cluster pathway is very favorable thermodynamically and kinetically for dehydrogenation. However, since CO binds strongly, it is likely to poison methanol decomposition to H{sub 2} and CO at low temperatures. In contrast, for the Cu cluster, CO poisoning is not likely to be a problem since it does not bind strongly, but the dehydrogenation steps are not energetically favorable. Pathways involving C-O bond cleavage are even less energetically favorable. The results are compared to our previous study of methanol decomposition on Pd{sub 4} and Pd{sub 8} clusters. Finally, all reaction energy changes and transition state energies, including those for the Pd clusters, are related in a linear, Broensted?Evans?Polanyi plot.

  7. The surface quasiliquid melt acceleration and the role of thermodynamic phase in the thermal decomposition of crystalline organic explosives

    SciTech Connect (OSTI)

    Henson, Bryan F

    2010-01-01

    We show that melt acceleration in the thermal decomposition of crystalline organic solids is a manifestation of the surface quasiliquid phase. We derive a single universal rate law for melt acceleration that is a simple function of the metastable liquid activity below the melting point, and has a zero order term proportional to the quasiliquid thickness. We argue that the underlying mechanisms of this model will provide a molecular definition for the stability of the class of secondary explosives.

  8. Thermal decomposition of 1,3,3-trinitroazetidine (TNAZ): A density functional theory and ab initio study

    SciTech Connect (OSTI)

    Veals, Jeffrey D.; Thompson, Donald L.

    2014-04-21

    Density functional theory and ab initio methods are employed to investigate decomposition pathways of 1,3,3-trinitroazetidine initiated by unimolecular loss of NO{sub 2} or HONO. Geometry optimizations are performed using M06/cc-pVTZ and coupled-cluster (CC) theory with single, double, and perturbative triple excitations, CCSD(T), is used to calculate accurate single-point energies for those geometries. The CCSD(T)/cc-pVTZ energies for NO{sub 2} elimination by NN and CN bond fission are, including zero-point energy (ZPE) corrections, 43.21 kcal/mol and 50.46 kcal/mol, respectively. The decomposition initiated by trans-HONO elimination can occur by a concerted H-atom and nitramine NO{sub 2} group elimination or by a concerted H-atom and nitroalkyl NO{sub 2} group elimination via barriers (at the CCSD(T)/cc-pVTZ level with ZPE corrections) of 47.00 kcal/mol and 48.27 kcal/mol, respectively. Thus, at the CCSD(T)/cc-pVTZ level, the ordering of these four decomposition steps from energetically most favored to least favored is: NO{sub 2} elimination by NN bond fission, HONO elimination involving the nitramine NO{sub 2} group, HONO elimination involving a nitroalkyl NO{sub 2} group, and finally NO{sub 2} elimination by CN bond fission.

  9. Early stages of spinodal decomposition in Fe–Cr resolved by in-situ small-angle neutron scattering

    SciTech Connect (OSTI)

    Hörnqvist, M. Thuvander, M.; Steuwer, A.; King, S.; Odqvist, J.; Hedström, P.

    2015-02-09

    In-situ, time-resolved small-angle neutron scattering (SANS) investigations of the early stages of the spinodal decomposition process in Fe–35Cr were performed at 773 and 798 K. The kinetics of the decomposition, both in terms of characteristic distance and peak intensity, followed a power-law behaviour from the start of the heat treatment (a′{sup  }= 0.10–0.11 and a″ = 0.67–0.86). Furthermore, the method allows tracking of the high–Q slope, which is a sensitive measure of the early stages of decomposition. Ex-situ SANS and atom probe tomography were used to verify the results from the in-situ investigations. Finally, the in-situ measurement of the evolution of the characteristic distance at 773 K was compared with the predictions from the Cahn-Hilliard-Cook model, which showed good agreement with the experimental data (a′{sup  }= 0.12–0.20 depending on the assumed mobility)

  10. Succession of Phylogeny and Function During Plant Litter Decomposition (2013 DOE JGI Genomics of Energy and Environment 8th Annual User Meeting)

    SciTech Connect (OSTI)

    Brodie, Eoin

    2013-03-01

    Eoin Brodie of Berkeley Lab on "Succession of phylogeny and function during plant litter decomposition" at the 8th Annual Genomics of Energy & Environment Meeting on March 27, 2013 in Walnut Creek, Calif.

  11. Analysis of the three-dimensional structure of a bubble wake using PIV and Galilean decomposition

    SciTech Connect (OSTI)

    Hassan, Y.A.; Schmidl, W.D.; Ortiz-Villafuerte, J.; Scharf, J.R.

    1999-07-01

    Bubbly flow plays a key role in a variety of natural and industrial processes. An accurate and complete description of the phase interactions in two-phase bubbly flow is not available at this time. These phase interactions are, in general, always three-dimensional and unsteady. Therefore, measurement techniques utilized to obtain qualitative and quantitative data from two-phase flow should be able to acquire transient and three-dimensional data, in order to provide information to test theoretical models and numerical simulations. Even for dilute bubble flows, in which bubble interaction is at a minimum, the turbulent motion of the liquid generated by the bubble is yet to be completely understood. For many years, the design of systems with bubbly flows was based primarily on empiricism. Dilute bubbly flows are an extension of single bubble dynamics, and therefore improvements in the description and modeling of single bubble motion, the flow field around the bubble, and the dynamical interactions between the bubble and the flow will consequently improve bubbly flow modeling. The improved understanding of the physical phenomena will have far-reaching benefits in upgrading the operation and efficiency of current processes and in supporting the development of new and innovative approaches. A stereoscopic particle image velocimetry measurement of the flow generated by the passage of a single air-bubble rising in stagnant water, in a circular pipe is presented. Three-dimensional velocity fields within the measurement zone were obtained. Ensemble-averaged instantaneous velocities for a specific bubble path were calculated and interpolated to obtain mean three-dimensional velocity fields. A Galilean velocity decomposition is used to study the vorticity generated in the flow.

  12. Development of microbial-enzyme-mediated decomposition model parameters through steady-state and dynamic analyses

    SciTech Connect (OSTI)

    Wang, Gangsheng; Post, Wilfred M; Mayes, Melanie

    2013-01-01

    We developed a Microbial-ENzyme-mediated Decomposition (MEND) model, based on the Michaelis-Menten kinetics, that describes the dynamics of physically defined pools of soil organic matter (SOC). These include particulate, mineral-associated, dissolved organic matter (POC, MOC, and DOC, respectively), microbial biomass, and associated exoenzymes. The ranges and/or distributions of parameters were determined by both analytical steady-state and dynamic analyses with SOC data from the literature. We used an improved multi-objective parameter sensitivity analysis (MOPSA) to identify the most important parameters for the full model: maintenance of microbial biomass, turnover and synthesis of enzymes, and carbon use efficiency (CUE). The model predicted an increase of 2 C (baseline temperature =12 C) caused the pools of POC-Cellulose, MOC, and total SOC to increase with dynamic CUE and decrease with constant CUE, as indicated by the 50% confidence intervals. Regardless of dynamic or constant CUE, the pool sizes of POC, MOC, and total SOC varied from 8% to 8% under +2 C. The scenario analysis using a single parameter set indicates that higher temperature with dynamic CUE might result in greater net increases in both POC-Cellulose and MOC pools. Different dynamics of various SOC pools reflected the catalytic functions of specific enzymes targeting specific substrates and the interactions between microbes, enzymes, and SOC. With the feasible parameter values estimated in this study, models incorporating fundamental principles of microbial-enzyme dynamics can lead to simulation results qualitatively different from traditional models with fast/slow/passive pools.

  13. Decomposition Pathway of Ammonia Borane on the Surface of nano-BN

    SciTech Connect (OSTI)

    Neiner, Doinita; Luedtke, Avery T.; Karkamkar, Abhijeet J.; Shaw, Wendy J.; Wang, Julia; Browning, Nigel; Autrey, Thomas; Kauzlarich, Susan M.

    2010-08-19

    Ammonia borane (AB) is under significant investigation as a possible hydrogen storage material. While many chemical additives have been demonstrated to have a significant positive effect on hydrogen release from ammonia borane, many provide additional complications in the regeneration cycle. Mechanically alloyed hexagonal BN (nano-BN) has been shown to facilitate the release of hydrogen from AB at lower temperature, with minimal induction time, less exothermically, and inert nano-BN may be easily removed during any regeneration of the spent AB. The samples were prepared by mechanically alloying AB with nano-BN. Raman spectroscopy indicates that the AB:nano-BN samples are physical mixtures of AB and h-BN. The release of hydrogen from AB:nano-BN mixtures as well as the decomposition products were characterized by 11B magic angle spinning (MAS) solid state NMR, TGA/DSC/MS with 15N labeled AB, and solution 11B NMR spectroscopy. The 11B MAS solid state NMR spectrum shows that diammonate of diborane (DADB) is present in the mechanically alloyed mixture, which drastically shortens the induction period for hydrogen release from AB. Analysis of the TGA/DSC/MS spectra using 15N labeled AB shows that all the borazine (BZ) produced in the reaction comes from AB and that increasing nano-BN surface area results in increased amounts of BZ. However, under high temperature, 150?C, isothermal conditions, the amount of BZ released was the same as for neat AB. High resolution transmission electron microscopy (HRTEM), selected area diffraction (SAD), and electron energy loss spectroscopy (EELS) of the initial and final nano-BN additive provide evidence for crystallinity loss but not significant chemical changes. The higher concentration of BZ observed for low temperature dehydrogenation of AB:nano-BN mixtures versus neat AB is attributed to a surface interaction that favors the formation of precursors which ultimately result in BZ. This pathway can be avoided through isothermal heating

  14. A periodic energy decomposition analysis method for the investigation of chemical bonding in extended systems

    SciTech Connect (OSTI)

    Raupach, Marc; Tonner, Ralf

    2015-05-21

    The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the bonding energy between two fragments (e.g., the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic, Pauli repulsion, and orbital relaxation energies. This is complemented by consideration of dispersion interactions via a pairwise scheme. One major extension toward a previous implementation [Philipsen and Baerends, J. Phys. Chem. B 110, 12470 (2006)] lies in the separate discussion of electrostatic and Pauli and the addition of a dispersion term. The pEDA presented here for an implementation based on atomic orbitals can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy, and k-space sampling. Four typical bonding scenarios for surface-adsorbate complexes were chosen to highlight the performance of the method representing insulating (CO on MgO(001)), metallic (H{sub 2} on M(001), M = Pd, Cu), and semiconducting (CO and C{sub 2}H{sub 2} on Si(001)) substrates. These examples cover diverse substrates as well as bonding scenarios ranging from weakly interacting to covalent (shared electron and donor acceptor) bonding. The results presented lend confidence that the pEDA will be a powerful tool for the analysis of surface-adsorbate bonding in the future, enabling the transfer of concepts like ionic and covalent bonding, donor-acceptor interaction, steric repulsion, and others to extended systems.

  15. Comparison of the thermal decompositions of HMX and 2,4-DNI for evaluation of slow cookoff response and long-term stability

    SciTech Connect (OSTI)

    Minier, L.; Behrens, R.; Bulusu, S.

    1995-12-01

    Thermal decomposition of HMX between 175C and 200C was studied using the simultaneous thermogravimetric modulated beam mass spectrometer with focus on initial stages of the decomposition. Thermal decomposition products are the same as in previous higher temperature experiments. The initial stages of the decomposition have an induction period followed by two acceleratory periods. Arrhenius parameters for the induction and two acceleratory periods are (Log(A)= 18.2 {plus_minus} 0.8, Ea = 48.2 {plus_minus} 1.8 kcal/mole), (Log (A) = 17.15 {plus_minus} 1.5 and Ea = 48.9 {plus_minus} 3.2 kcal/mole), (Log (A) = 19.1 {plus_minus} 3.0 and Ea = 52.1 {plus_minus} 6.3 kcal/mole). This data can be used to calculate the time and temperature required to decompose a desired fraction of a test sample testing the effect of thermal degradation on sensitivity or bum rates. It can also be used to estimate the extent of decomposition expected under normal storage conditions for munitions containing HMX. This data, along with previous mechanistic studies conducted at higher temperatures, suggest that the process that controls the early stages of decomposition of HMX in the solid phase is scission of the N-NO{sub 2} bond, reaction of the N0{sub 2} within a lattice cage to form the mononitroso analogue of HMX and decomposition of the mononitroso HMX within the HMX lattice to form gaseous products that are retained in bubbles or diffuse into the surrounding lattice. These methods evaluating HMX can be used to evaluate new energetic materials such as 2,4-DNI. The early 2,4-DNI thermal decomposition is characterized by an initial decomposition, an apparent induction period, then an initial acceleratory period. The main gaseous products are NO, C0{sub 2}, HNCO, H{sub 2}0, N{sub 2}, CO, HCN and C{sub 2}N{sub 2}. The presence of adsorbed and occluded H{sub 2}0 is the major cause of the early decomposition.

  16. Technical Note: MRI only prostate radiotherapy planning using the statistical decomposition algorithm

    SciTech Connect (OSTI)

    Siversson, Carl; Nordström, Fredrik; Nilsson, Terese; Nyholm, Tufve; Jonsson, Joakim; Gunnlaugsson, Adalsteinn; Olsson, Lars E.

    2015-10-15

    Purpose: In order to enable a magnetic resonance imaging (MRI) only workflow in radiotherapy treatment planning, methods are required for generating Hounsfield unit (HU) maps (i.e., synthetic computed tomography, sCT) for dose calculations, directly from MRI. The Statistical Decomposition Algorithm (SDA) is a method for automatically generating sCT images from a single MR image volume, based on automatic tissue classification in combination with a model trained using a multimodal template material. This study compares dose calculations between sCT generated by the SDA and conventional CT in the male pelvic region. Methods: The study comprised ten prostate cancer patients, for whom a 3D T2 weighted MRI and a conventional planning CT were acquired. For each patient, sCT images were generated from the acquired MRI using the SDA. In order to decouple the effect of variations in patient geometry between imaging modalities from the effect of uncertainties in the SDA, the conventional CT was nonrigidly registered to the MRI to assure that their geometries were well aligned. For each patient, a volumetric modulated arc therapy plan was created for the registered CT (rCT) and recalculated for both the sCT and the conventional CT. The results were evaluated using several methods, including mean average error (MAE), a set of dose-volume histogram parameters, and a restrictive gamma criterion (2% local dose/1 mm). Results: The MAE within the body contour was 36.5 ± 4.1 (1 s.d.) HU between sCT and rCT. Average mean absorbed dose difference to target was 0.0% ± 0.2% (1 s.d.) between sCT and rCT, whereas it was −0.3% ± 0.3% (1 s.d.) between CT and rCT. The average gamma pass rate was 99.9% for sCT vs rCT, whereas it was 90.3% for CT vs rCT. Conclusions: The SDA enables a highly accurate MRI only workflow in prostate radiotherapy planning. The dosimetric uncertainties originating from the SDA appear negligible and are notably lower than the uncertainties

  17. Effect of moisture on leaf litter decomposition and its contribution to soil respiration in a temperate forest

    SciTech Connect (OSTI)

    Cisneros-Dozal, Luz Maria; Trumbore, Susan E.; Hanson, Paul J

    2007-01-01

    The degree to which increased soil respiration rates following wetting is caused by plant (autotrophic) versus microbial (heterotrophic) processes, is still largely uninvestigated. Incubation studies suggest microbial processes play a role but it remains unclear whether there is a stimulation of the microbial population as a whole or an increase in the importance of specific substrates that become available with wetting of the soil. We took advantage of an ongoing manipulation of leaf litter 14C contents at the Oak Ridge Reservation, Oak Ridge, Tennessee, to (1) determine the degree to which an increase in soil respiration rates that accompanied wetting of litter and soil, following a short period of drought, could be explained by heterotrophic contributions; and (2) investigate the potential causes of increased heterotrophic respiration in incubated litter and 0-5 cm mineral soil. The contribution of leaf litter decomposition increased from 6 3 mg C m 2 hr 1 during a transient drought, to 63 18 mg C m 2 hr 1 immediately after water addition, corresponding to an increase in the contribution to soil respiration from 5 2% to 37 8%. The increased relative contribution was sufficient to explain all of the observed increase in soil respiration for this one wetting event in the late growing season. Temperature (13 C versus 25 C) and moisture (dry versus field capacity) conditions did not change the relative contributions of different decomposition substrates in incubations, suggesting that more slowly cycling C has at least the same sensitivity to decomposition as faster cycling organic C at the temperature and moisture conditions studied.

  18. ENERGY EFFICIENCY LIMITS FOR A RECUPERATIVE BAYONET SULFURIC ACID DECOMPOSITION REACTOR FOR SULFUR CYCLE THERMOCHEMICAL HYDROGEN PRODUCTION

    SciTech Connect (OSTI)

    Gorensek, M.; Edwards, T.

    2009-06-11

    A recuperative bayonet reactor design for the high-temperature sulfuric acid decomposition step in sulfur-based thermochemical hydrogen cycles was evaluated using pinch analysis in conjunction with statistical methods. The objective was to establish the minimum energy requirement. Taking hydrogen production via alkaline electrolysis with nuclear power as the benchmark, the acid decomposition step can consume no more than 450 kJ/mol SO{sub 2} for sulfur cycles to be competitive. The lowest value of the minimum heating target, 320.9 kJ/mol SO{sub 2}, was found at the highest pressure (90 bar) and peak process temperature (900 C) considered, and at a feed concentration of 42.5 mol% H{sub 2}SO{sub 4}. This should be low enough for a practical water-splitting process, even including the additional energy required to concentrate the acid feed. Lower temperatures consistently gave higher minimum heating targets. The lowest peak process temperature that could meet the 450-kJ/mol SO{sub 2} benchmark was 750 C. If the decomposition reactor were to be heated indirectly by an advanced gas-cooled reactor heat source (50 C temperature difference between primary and secondary coolants, 25 C minimum temperature difference between the secondary coolant and the process), then sulfur cycles using this concept could be competitive with alkaline electrolysis provided the primary heat source temperature is at least 825 C. The bayonet design will not be practical if the (primary heat source) reactor outlet temperature is below 825 C.

  19. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria

    SciTech Connect (OSTI)

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-07-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO₂ emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO₂ emission constituted 1,200 µm C g⁻¹ soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO₂ emission constituted 2,000 µm C g⁻¹ soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO₂ emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of

  20. Reactions of tungsten-titanium alloys with decomposition products from a glow UHF discharge in a tetrafluoromethane-oxygen mixture

    SciTech Connect (OSTI)

    Amirov, I.I.; Vinogradov, G.K.; Slovetskii, D.I.

    1988-07-01

    Decomposition products from tetrafluoromethane mixed with oxygen react with WTi alloy in an HF glow discharge, the extent of reaction being dependent on the atomic fluorine concentration, temperature, and surface potential. The rates of reaction with the CF/sub 4/ products are proportional to the atomic fluorine concentrations. The effective activation energies have been determined for the atomic fluorine reacting with the alloy components in various gases. The metal removal rate increases when the specimen is negative with respect to the plasma potential, which is ascribed to the surface being bombarded by positive ions or to the electric field affecting the surface reaction rates.

  1. Phase decomposition in an Fe-40 at.% Cr alloy after isothermal aging and its effect on hardening

    SciTech Connect (OSTI)

    Lopez-Hirata, Victor M. Soriano-Vargas, Orlando; Rosales-Dorantes, Hector J.; Saucedo Munoz, Maribel L.

    2011-08-15

    The phase decomposition process of an Fe-40 at.% Cr alloy was studied after isothermal aging at 475 and 500 deg. C using a high-resolution transmission electron microscope, as well as hardness measurements. High-resolution transmission electron microscope observations showed that the hardening behavior is associated with the formation of the nanometric coherent decomposed Cr-rich and Fe-rich phases with irregular shape and interconnected as expected for a spinodally-decomposed alloy. As the aging progressed, coherent rounded Cr-rich phase precipitates were observed in the Fe-rich phase matrix. The coarsening process of the Cr-rich phase was observed for aging times up to 750 h. Nevertheless, no decrease in hardness with time was observed because of the nanometric size of the Cr-rich phase, less than 10 nm. Aging hardening was higher at 500 deg. C because of the higher decomposition kinetics. - Research Highlights: {yields} Spinodally-decomposed phases showed an interconnected and irregular shape in aged Fe-Cr alloy. {yields} Further aging promoted the formation of nanometric coherent rounded Cr-rich precipitates. {yields} Nanometric Cr-rich phases are responsible for the age hardening. {yields} Coarsening process of these nanometric Cr-rich precipitates caused no decrease in hardness.

  2. Identifying the Oil Price-Macroeconomy Relationship: An Empirical Mode Decomposition Analysis of U.S. Data

    SciTech Connect (OSTI)

    Oladosu, Gbadebo A

    2009-01-01

    This work applies the empirical mode decomposition (EMD) method to data on real quarterly oil price (West Texas Intermediate - WTI) and U.S. gross domestic product (GDP). This relatively new method is adaptive and capable of handling non-linear and non-stationary data. Correlation analysis of the decomposition results was performed and examined for insights into the oil-macroeconomy relationship. Several components of this relationship were identified. However, the principal one is that the medium-run cyclical component of the oil price exerts a negative and exogenous influence on the main cyclical component of the GDP. This can be interpreted as the supply-driven or supply-shock component of the oil price-GDP relationship. In addition, weak correlations suggesting a lagging demand-driven, an expectations-driven, and a long-run supply-driven component of the relationship were also identified. Comparisons of these findings with significant oil supply disruption and recession dates were supportive. The study identified a number of lessons applicable to recent oil market events, including the eventuality of persistent economic and price declines following a long oil price run-up. In addition, it was found that oil-market related exogenous events are associated with short- to medium-run price implications regardless of whether they lead to actual supply disruptions.

  3. Thioozonide decomposition: sulfur and oxygen atom transfer. Evidence for the formation of a carbonyl O-sulfide intermediate

    SciTech Connect (OSTI)

    Matturro, M.G.; Reynolds, R.P.; Kastrup, R.V.; Pictroski, C.F.

    1986-05-14

    The chemistry of ozonides is of considerable interest from a practical and theoretical viewpoint. Thioozonide 1, formally the monosulfur-substituted ozonide of dimethylcyclobutadiene, has been proposed as an intermediate in the room temperature photooxidation of 2,5-dimethylthiophene. Subsequent low-temperature studies confirmed this structural assignment. When 1 is allowed to warm to room temperature, it rearranges to a mixture of sulfine 2 and cis- and trans-3-hexene-2,5-diones (3c and 3t). Recent examination of the thermal decomposition of 1 has led to a proposed mechanism involving a carbonyl sulfide 4 as an intermediate along the sulfur expulsion pathway to 3c; however, no experimental support for this hypothesis was given. Carbonyl O-sulfides have also been implicated as intermediates from the photolysis of oxathiiranes. The authors report evidence for the formation of 4 during the decomposition of 1 and that elemental sulfur (S/sub 8/) is formed during the reaction by concatenation of sulfur atoms or fragments (S/sub 2/, S/sub 3/, etc.).

  4. Thermodynamic studies of studtite thermal decomposition pathways via amorphous intermediates UO3, U2O7, and UO4

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

    Guo, Xiaofeng; Wu, Di; Xu, Hongwu; Burns, Peter C.; Navrotsky, Alexandra

    2016-06-08

    The thermal decomposition of studtite (UO2)O2(H2O)2·2H2O results in a series of intermediate X-ray amorphous materials with general composition UO3+x (x = 0, 0.5, 1). As an extension of a structural study on U2O7, this work provides detailed calorimetric data on these amorphous oxygen-rich materials since their energetics and thermal stability are unknown. These were characterized in situ by thermogravimetry, and mass spectrometry. Ex situ X-ray diffraction and infrared spectroscopy characterized their chemical bonding and local structures. This detailed characterization formed the basis for obtaining formation enthalpies by high temperature oxide melt solution calorimetry. The thermodynamic data demonstrate the metastability ofmore » the amorphous UO3+x materials, and explain their irreversible and spontaneous reactions to generate oxygen and form metaschoepite. Thus, formation of studtite in the nuclear fuel cycle, followed by heat treatment, can produce metastable amorphous UO3+x materials that pose the risk of significant O2 gas. Quantitative knowledge of the energy landscape of amorphous UO3+x was provided for stability analysis and assessment of conditions for decomposition.« less

  5. Photochemical fabrication of size-controllable gold nanoparticles on chitosan and their application on catalytic decomposition of acetaldehyde

    SciTech Connect (OSTI)

    Yu, Chung-Chin; Yang, Kuang-Hsuan; Liu, Yu-Chuan; Chen, Bo-Chuen

    2010-07-15

    In this work, we report a new pathway to prepare size-controllable gold nanoparticles (NPs) on chitosan (Ch) in aqueous solutions for improving catalytic decomposition of acetaldehyde by pure gold NPs at room temperature. First, Au substrates were cycled in deoxygenated aqueous solutions containing 0.1N NaCl and 1 g/L Ch from -0.28 to +1.22 V vs Ag/AgCl at 500 mV/s for 200 scans. Then the solutions were irradiated with UV lights of different wavelengths to prepare size-controllable Au NPs on Ch. Experimental results indicate that the particle sizes of prepared NPs are increased when UV lights with longer wavelengths were employed. The particle sizes of resulted Au NPs can be controlled from 10 to 50 nm. Moreover, the decomposition of acetaldehydes in wines can be significantly enhanced by ca. 190% of magnitude due to the contribution of the adsorption of Au NPs on Ch.

  6. A domain decomposition method of stochastic PDEs: An iterative solution techniques using a two-level scalable preconditioner

    SciTech Connect (OSTI)

    Subber, Waad Sarkar, Abhijit

    2014-01-15

    Recent advances in high performance computing systems and sensing technologies motivate computational simulations with extremely high resolution models with capabilities to quantify uncertainties for credible numerical predictions. A two-level domain decomposition method is reported in this investigation to devise a linear solver for the large-scale system in the Galerkin spectral stochastic finite element method (SSFEM). In particular, a two-level scalable preconditioner is introduced in order to iteratively solve the large-scale linear system in the intrusive SSFEM using an iterative substructuring based domain decomposition solver. The implementation of the algorithm involves solving a local problem on each subdomain that constructs the local part of the preconditioner and a coarse problem that propagates information globally among the subdomains. The numerical and parallel scalabilities of the two-level preconditioner are contrasted with the previously developed one-level preconditioner for two-dimensional flow through porous media and elasticity problems with spatially varying non-Gaussian material properties. A distributed implementation of the parallel algorithm is carried out using MPI and PETSc parallel libraries. The scalabilities of the algorithm are investigated in a Linux cluster.

  7. Synthesis of polycrystalline Co{sub 3}O{sub 4} nanowires with excellent ammonium perchlorate catalytic decomposition property

    SciTech Connect (OSTI)

    Zhou, Hai; Lv, Baoliang; Wu, Dong; Xu, Yao

    2014-12-15

    Graphical abstract: Co{sub 3}O{sub 4} nanowires with excellent ammonium perchlorate catalytic decomposition property were synthesized via a methanamide-assisted hydrolysis and subsequent dissolution–recrystallization process in the presence of methanamide. - Abstract: Co{sub 3}O{sub 4} nanowires, with the length of tens of micrometers and the width of several hundred nanometers, were produced by a hydrothermal treatment and a post-anneal process. X-ray diffraction (XRD) result showed that the Co{sub 3}O{sub 4} nanowires belong to cubic crystal system. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analysis indicated that the Co{sub 3}O{sub 4} nanowires, composed by single crystalline nanoparticles, were of polycrystalline nature. On the basis of time-dependent experiments, methanamide-assisted hydrolysis and subsequent dissolution–recrystallization process were used to explain the precursors' formation process of the polycrystalline Co{sub 3}O{sub 4} nanowires. The TGA experiments showed that the as-obtained Co{sub 3}O{sub 4} nanowires can catalyze the thermal decomposition of ammonium perchlorate (AP) effectively.

  8. Shock tube and theoretical studies on the thermal decomposition of propane : evidence for a roaming radical channel.

    SciTech Connect (OSTI)

    Sivaramakrishnan, R.; Su, M.-C.; Michael, J. V.; Klippenstein, S. J.; Harding, L. B.; Ruscic, B.

    2011-04-21

    The thermal decomposition of propane has been studied using both shock tube experiments and ab initio transition state theory-based master equation calculations. Dissociation rate constants for propane have been measured at high temperatures behind reflected shock waves using high-sensitivity H-ARAS detection and CH{sub 3} optical absorption. The two major dissociation channels at high temperature are C{sub 3}H{sub 8} {yields} CH{sub 3} + C{sub 2}H{sub 5} (eq 1a) and C{sub 3}H{sub 8} {yields} CH{sub 4} + C{sub 2}H{sub 4} (eq 1b). Ultra high-sensitivity ARAS detection of H-atoms produced from the decomposition of the product, C{sub 2}H{sub 5}, in (1a), allowed measurements of both the total decomposition rate constants, k{sub total}, and the branching to radical products, k{sub 1a}/k{sub total}. Theoretical analyses indicate that the molecular products are formed exclusively through the roaming radical mechanism and that radical products are formed exclusively through channel 1a. The experiments were performed over the temperature range 1417-1819 K and gave a minor contribution of (10 {+-} 8%) due to roaming. A multipass CH{sub 3} absorption diagnostic using a Zn resonance lamp was also developed and characterized in this work using the thermal decomposition of CH{sub 3}I as a reference reaction. The measured rate constants for CH{sub 3}I decomposition agreed with earlier determinations from this laboratory that were based on I-atom ARAS measurements. This CH{sub 3} diagnostic was then used to detect radicals from channel 1a allowing lower temperature (1202-1543 K) measurements of k1a to be determined. Variable reaction coordinate-transition state theory was used to predict the high pressure limits for channel (1a) and other bond fission reactions in C{sub 3}H{sub 8}. Conventional transition state theory calculations were also used to estimate rate constants for other tight transition state processes. These calculations predict a negligible contribution (<1%) from

  9. A full-spectral Bayesian reconstruction approach based on the material decomposition model applied in dual-energy computed tomography

    SciTech Connect (OSTI)

    Cai, C.; Rodet, T.; Mohammad-Djafari, A.; Legoupil, S.

    2013-11-15

    Purpose: Dual-energy computed tomography (DECT) makes it possible to get two fractions of basis materials without segmentation. One is the soft-tissue equivalent water fraction and the other is the hard-matter equivalent bone fraction. Practical DECT measurements are usually obtained with polychromatic x-ray beams. Existing reconstruction approaches based on linear forward models without counting the beam polychromaticity fail to estimate the correct decomposition fractions and result in beam-hardening artifacts (BHA). The existing BHA correction approaches either need to refer to calibration measurements or suffer from the noise amplification caused by the negative-log preprocessing and the ill-conditioned water and bone separation problem. To overcome these problems, statistical DECT reconstruction approaches based on nonlinear forward models counting the beam polychromaticity show great potential for giving accurate fraction images.Methods: This work proposes a full-spectral Bayesian reconstruction approach which allows the reconstruction of high quality fraction images from ordinary polychromatic measurements. This approach is based on a Gaussian noise model with unknown variance assigned directly to the projections without taking negative-log. Referring to Bayesian inferences, the decomposition fractions and observation variance are estimated by using the joint maximum a posteriori (MAP) estimation method. Subject to an adaptive prior model assigned to the variance, the joint estimation problem is then simplified into a single estimation problem. It transforms the joint MAP estimation problem into a minimization problem with a nonquadratic cost function. To solve it, the use of a monotone conjugate gradient algorithm with suboptimal descent steps is proposed.Results: The performance of the proposed approach is analyzed with both simulated and experimental data. The results show that the proposed Bayesian approach is robust to noise and materials. It is also

  10. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria

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

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-07-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO₂ emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis ofmore » amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO₂ emission constituted 1,200 µm C g⁻¹ soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO₂ emission constituted 2,000 µm C g⁻¹ soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO₂ emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and

  11. Thermal decomposition of Mg/V hydrotalcites and catalytic performance of the products in oxidative dehydrogenation reactions

    SciTech Connect (OSTI)

    Holgado, M.J.; Labajos, F.M.; Montero, M.J.S.; Rives, V

    2003-11-26

    Layered double hydroxides with the hydrotalcite-type structure containing Mg{sup 2+} and V{sup 3+} in the brucite-like layers, possessing different V contents, have been prepared and characterised by elemental chemical analysis, powder X-ray diffraction, Fourier transform infrared (FT-IR) spectroscopy and specific surface area and porosity assessment by nitrogen adsorption; thermal decomposition was studied by Differential Thermal Analysis and Thermogravimetric Analysis. The solids obtained after calcination at 800 deg. C were tested as catalysts for oxidative dehydrogenation of propane and n-butane. Results indicate that the relative amounts of Mg{sub 3}(VO{sub 4}) and MgO, depending on the V content in the starting hydrotalcite, determines the performance of the catalysts in oxidative dehydrogenation of propane and n-butane.

  12. MHD Structure Analysis by Singular Value Decomposition as a Tool for ECRH RT-Control of Instabilities on FTU

    SciTech Connect (OSTI)

    Marchetto, C.; Cirant, S.; Granucci, G.; Lazzaro, E.; Gandini, F.; Esposito, B.

    2009-11-26

    In this work we present the results obtained applying Singular Value Decomposition (SVD) on a Mirnov coil array in FTU discharges where experiments on MHD stabilization or disruption avoidance via ECRH were performed. In these shots the mode analysis has been consolidated off line by means of FFT and SXR-tomography. Although the Mirnov setting was not necessarily optimised, results show that the algorithm based on SVD is able to detect the mode with a precision equal or better than the FFT, while acting on a smaller time interval. The short execution time required, even in the present preliminary form, suggests that this analysis can be a suitable tool to be implemented in a real time control chain.

  13. System and methods for determining masking signals for applying empirical mode decomposition (EMD) and for demodulating intrinsic mode functions obtained from application of EMD

    DOE Patents [OSTI]

    Senroy, Nilanjan; Suryanarayanan, Siddharth

    2011-03-15

    A computer-implemented method of signal processing is provided. The method includes generating one or more masking signals based upon a computed Fourier transform of a received signal. The method further includes determining one or more intrinsic mode functions (IMFs) of the received signal by performing a masking-signal-based empirical mode decomposition (EMD) using the at least one masking signal.

  14. Catalytic decomposition of S sub 2 F sub 10 and its implications on sampling and detection from SF sub 6 -insulated equipment

    SciTech Connect (OSTI)

    Olthoff, J.K.; Van Brunt, R.J.; Herron, J.T. ); Sauers, I.; Harman, G. )

    1990-01-01

    Recent findings indicate that S{sub 2}F{sub 10} is unstable with respect to decomposition on a surface. This paper reports the first results of a study investigating the mechanisms and rates of surface decomposition of S{sub 2}F{sub 10} under various conditions. Initial results indicate that surface decomposition rates on stainless steel increase with increased water content, temperature, and surface-to-volume ratio, and with decreased gas pressure. The implications of these results for the preparation and storage of S{sub 2}F{sub 10} samples are discussed. Additionally, the use of this surface decomposition mechanism to enhance the detection sensitivity of small concentrations of S{sub 2}F{sub 10} in SF{sub 6} using a gas chromatograph/mass spectrometer (GC/MS) is investigated. Detection sensitivities of 1 ppM by volume (ppM{sub v}) of S{sub 2}F{sub 10} in SF{sub 6} are routinely achievable using this new technique. 14 refs., 8 figs.

  15. Silver-mordenite for radiologic gas capture from complex streams. Dual catalytic CH3I decomposition and I confinement

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

    Nenoff, Tina M.; Rodriguez, Mark A.; Soelberg, Nick R.; Chapman, Karena W.

    2014-05-09

    The selective capture of radiological iodine (129I) is a persistent concern for safe nuclear energy. In these nuclear fuel reprocessing scenarios, the gas streams to be treated are extremely complex, containing several distinct iodine-containing molecules amongst a large variety of other species. Silver-containing mordenite (MOR) is a longstanding benchmark for radioiodine capture, reacting with molecular iodine (I2) to form AgI. However the mechanisms for organoiodine capture is not well understood. Here we investigate the capture of methyl iodide from complex mixed gas streams by combining chemical analysis of the effluent gas stream with in depth characterization of the recovered sorbent.more » Tools applied include infrared spectroscopy, thermogravimetric analysis with mass spectrometry, micro X-ray fluorescence, powder X-ray diffraction analysis, and pair distribution function analysis. Moreover, the MOR zeolite catalyzes decomposition of the methyl iodide through formation of surface methoxy species (SMS), which subsequently reacts with water in the mixed gas stream to form methanol, and with methanol to form dimethyl ether, which are both detected downstream in the effluent. The liberated iodine reacts with Ag in the MOR pore to the form subnanometer AgI clusters, smaller than the MOR pores, suggesting that the iodine is both physically and chemically confined within the zeolite.« less

  16. Spontaneous formation of nanostructures by surface spinodal decomposition in GaAs{sub 1?x}Bi{sub x} epilayers

    SciTech Connect (OSTI)

    Luna, E. Wu, M.; Trampert, A.; Puustinen, J.; Guina, M.

    2015-05-14

    We report on the spontaneous formation of lateral composition modulations (LCMs) in Ga(As,Bi) epilayers grown by low-temperature (<300?C) molecular beam epitaxy (MBE) on GaAs(001). Both cross-section and plan-view transmission electron microscopy techniques are used to investigate the nature of the LCMs, consisting of Bi-rich cylinder-like nanostructures lying along the [001] growth direction. The observed LCMs are the consequence of a two-dimensional phase separation process occurring at the surface of the growing epilayers, and their columnar nature is consistent with a surface-directed spinodal decomposition process. Although LCMs are thermodynamically driven, we show how they can be kinetically controlled, in particular, through the As/Ga flux ratio and the substrate temperature. This is a result of LCMs developing from surface atomic diffusion processes, since the atomic dimer configurations on the surface alter adatom diffusivity. The significant role of the surface reconstructions is also discussed.

  17. Blip decomposition of the path integral: Exponential acceleration of real-time calculations on quantum dissipative systems

    SciTech Connect (OSTI)

    Makri, Nancy

    2014-10-07

    The real-time path integral representation of the reduced density matrix for a discrete system in contact with a dissipative medium is rewritten in terms of the number of blips, i.e., elementary time intervals over which the forward and backward paths are not identical. For a given set of blips, it is shown that the path sum with respect to the coordinates of all remaining time points is isomorphic to that for the wavefunction of a system subject to an external driving term and thus can be summed by an inexpensive iterative procedure. This exact decomposition reduces the number of terms by a factor that increases exponentially with propagation time. Further, under conditions (moderately high temperature and/or dissipation strength) that lead primarily to incoherent dynamics, the “fully incoherent limit” zero-blip term of the series provides a reasonable approximation to the dynamics, and the blip series converges rapidly to the exact result. Retention of only the blips required for satisfactory convergence leads to speedup of full-memory path integral calculations by many orders of magnitude.

  18. Final technical report. Can microbial functional traits predict the response and resilience of decomposition to global change?

    SciTech Connect (OSTI)

    Allison, Steven D.

    2015-09-24

    The role of specific micro-organisms in the carbon cycle, and their responses to environmental change, are unknown in most ecosystems. This knowledge gap limits scientists’ ability to predict how important ecosystem processes, like soil carbon storage and loss, will change with climate and other environmental factors. The investigators addressed this knowledge gap by transplanting microbial communities from different environments into new environments and measuring the response of community composition and carbon cycling over time. Using state-of-the-art sequencing techniques, computational tools, and nanotechnology, the investigators showed that microbial communities on decomposing plant material shift dramatically with natural and experimentally-imposed drought. Microbial communities also shifted in response to added nitrogen, but the effects were smaller. These changes had implications for carbon cycling, with lower rates of carbon loss under drought conditions, and changes in the efficiency of decomposition with nitrogen addition. Even when transplanted into the same conditions, microbial communities from different environments remained distinct in composition and functioning for up to one year. Changes in functioning were related to differences in enzyme gene content across different microbial groups. Computational approaches developed for this project allowed the conclusions to be tested more broadly in other ecosystems, and new computer models will facilitate the prediction of microbial traits and functioning across environments. The data and models resulting from this project benefit the public by improving the ability to predict how microbial communities and carbon cycling functions respond to climate change, nutrient enrichment, and other large-scale environmental changes.

  19. Mass-radius relations and core-envelope decompositions of super-Earths and sub-Neptunes

    SciTech Connect (OSTI)

    Howe, Alex R.; Burrows, Adam; Verne, Wesley E-mail: burrows@astro.princeton.edu

    2014-06-01

    Many exoplanets have been discovered with radii of 1-4 R {sub ?}, between that of Earth and Neptune. A number of these are known to have densities consistent with solid compositions, while others are 'sub-Neptunes' likely to have significant H{sub 2}-He envelopes. Future surveys will no doubt significantly expand these populations. In order to understand how the measured masses and radii of such planets can inform their structures and compositions, we construct models both for solid layered planets and for planets with solid cores and gaseous envelopes, exploring a range of core masses, H{sub 2}-He envelope masses, and associated envelope entropies. For planets in the super-Earth/sub-Neptune regime for which both radius and mass are measured, we estimate how each is partitioned into a solid core and gaseous envelope, associating a specific core mass and envelope mass with a given exoplanet. We perform this decomposition for both ''Earth-like'' rock-iron cores and pure ice cores, and find that the necessary gaseous envelope masses for this important sub-class of exoplanets must range very widely from zero to many Earth masses, even for a given core mass. This result bears importantly on exoplanet formation and envelope evaporation processes.

  20. TU-F-18A-04: Use of An Image-Based Material-Decomposition Algorithm for Multi-Energy CT to Determine Basis Material Densities

    SciTech Connect (OSTI)

    Li, Z; Leng, S; Yu, L; McCollough, C

    2014-06-15

    Purpose: Published methods for image-based material decomposition with multi-energy CT images have required the assumption of volume conservation or accurate knowledge of the x-ray spectra and detector response. The purpose of this work was to develop an image-based material-decomposition algorithm that can overcome these limitations. Methods: An image-based material decomposition algorithm was developed that requires only mass conservation (rather than volume conservation). With this method, using multi-energy CT measurements made with n=4 energy bins, the mass density of each basis material and of the mixture can be determined without knowledge of the tube spectra and detector response. A digital phantom containing 12 samples of mixtures from water, calcium, iron, and iodine was used in the simulation (Siemens DRASIM). The calibration was performed by using pure materials at each energy bin. The accuracy of the technique was evaluated in noise-free and noisy data under the assumption of an ideal photon-counting detector. Results: Basis material densities can be estimated accurately by either theoretic calculation or calibration with known pure materials. The calibration approach requires no prior information about the spectra and detector response. Regression analysis of theoretical values versus estimated values results in excellent agreement for both noise-free and noisy data. For the calibration approach, the R-square values are 0.9960+/−0.0025 and 0.9476+/−0.0363 for noise-free and noisy data, respectively. Conclusion: From multi-energy CT images with n=4 energy bins, the developed image-based material decomposition method accurately estimated 4 basis material density (3 without k-edge and 1 with in the range of the simulated energy bins) even without any prior information about spectra and detector response. This method is applicable to mixtures of solutions and dissolvable materials, where volume conservation assumptions do not apply. CHM receives

  1. Spectroscopic study of reaction intermediates and mechanisms in nitramine decomposition and combustion. Final report, 20 March 1992-19 March 1995

    SciTech Connect (OSTI)

    Jacox, M.B.

    1995-05-20

    The infrared spectra of reaction intermediates trapped in solid neon were studied in order to support the development of diagnostics for short-lived species which are reaction carriers in nitramine decomposition and combustion and to derive information about reactions which are important in the condensed-phase decomposition of nitramines. Nitromethane and monomethylnitramine were used as model compounds in these studies. Evidence was obtained for the formation of water complexes with both of these species. The results support the water-catalyzed decomposition mechanism for nitramines that was proposed by Melius. Studies of the photodecomposition of isotopically substituted monomethylnitramine demonstrate that four different groups of products are formed. Tentative spectral assignments are made for the aci-isomer of monomethylnitramine and for CH3NHONO. The final photodecomposition products are CH4, NO, CH3OH, and N20. Other studies have provided evidence for the formation of a weakly bonded complex of H2 with H20, as well as spectral data for the HCC free radical and for the H20+, N02+, NO(2-), and NO(3-), molecular ions.

  2. Energy savings and structural changes in the U.S. economy: Evidence from disaggregated data using decomposition techniques

    SciTech Connect (OSTI)

    Murtishaw, Scott; Schipper, Lee

    2001-12-01

    During the period 1973 to 1985, the U.S. economy saved energy in virtually every sector. Much of this period of energy saving was also marked by a significant drop in the ratio of energy use to GDP. However, since 1985 there has been a slowdown in the rate of energy saving, as key energy intensities (space heating, automobile driving, etc.) have declined less rapidly since 1985 than before. This paper examines delivered (or final) energy consumption trends from the early 1970s to 1994 and provides a framework for measuring key changes that affect U.S. energy use. Starting with estimates of outputs or activity levels for thirty major energy end uses, and energy intensities of each end use, we use the Adaptive Weighted Divisia decomposition to measure the impact of changes in the structure of the U.S. economy. In contrast to many similar decomposition studies, we define measures of structural changes for both households and branches of transportation. We find that between 1973 and 1985, lower energy intensities (corrected to average winter heating demand) reduced U.S. energy uses by about 1.7% per year, while structural changes reduced energy uses by 0.4% per year. After 1985, when oil prices declined markedly, intensities fell by only 0.8% per year and structural changes actually increased energy use by 0.4% per year. In the 1990s energy intensities in some industries have even edged upward. Changes in the ratio of energy to GDP (E/GDP) are affected both by intensities and the changes in the demand for energy services relative to GDP. During the first period, from 1973 to 1985, GDP increased faster than the growth in key structural and activity parameters that determine demand for energy services (such as home area, appliance ownership, and motor vehicle use) by 1.5% per year. From 1985 to 1994 the difference dropped to less than 0.3% per year, largely due to the reversal of structural trends. Thus, the sharp fall in the rate of decline in E/GDP from -3.1% to -1

  3. Decomposition and vibrational relaxation in CH{sub 3}I and self-reaction of CH{sub 3} radicals.

    SciTech Connect (OSTI)

    Yang, X.; Goldsmith, C. F.; Tranter, R. S.

    2009-07-01

    Vibrational relaxation and dissociation of CH{sub 3}I, 2-20% in krypton, have been investigated behind incident shock waves in a diaphragmless shock tube at 20, 66, 148, and 280 Torr and 630-2200 K by laser schlieren densitometry. The effective collision energy obtained from the vibrational relaxation experiments has a small, positive temperature dependence, {Delta}E{sub down} = 63 x (T/298){sup 0.56} cm{sup -1}. First-order rate coefficients for dissociation of CH{sub 3}I show a strong pressure dependence and are close to the low-pressure limit. Restricted-rotor Gorin model RRKM calculations fit the experimental results very well with {Delta}E{sub down} = 378 x (T/298){sup 0.457} cm{sup -1}. The secondary chemistry of this reaction system is dominated by reactions of methyl radicals and the reaction of the H atom with CH{sub 3}I. The results of the decomposition experiments are very well simulated with a model that incorporates methyl recombination and reactions of methylene. Second-order rate coefficients for ethane dissociation to two methyl radicals were derived from the experiments and yield k = (4.50 {+-} 0.50) x 10{sup 17} exp(-32709/T) cm{sup 3} mol{sup -1} s{sup -1}, in good agreement with previous measurements. Rate coefficients for H + CH{sub 3}I were also obtained and give k = (7.50 {+-} 1.0) x 10{sup 13} exp(-601/T) cm{sup 3} mol{sup -1} s{sup -1}, in reasonable agreement with a previous experimental value.

  4. Decomposition of carbohydrate wastes

    DOE Patents [OSTI]

    Appell, Herbert R.; Pantages, Peter

    1976-11-02

    Carbohydrate waste materials are decomposed to form a gaseous fuel product by contacting them with a transition metal catalyst at elevated temperature substantially in the absence of water.

  5. Validation of heat transfer, thermal decomposition, and container pressurization of polyurethane foam using mean value and Latin hypercube sampling approaches

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

    Scott, Sarah N.; Dodd, Amanda B.; Larsen, Marvin E.; Suo-Anttila, Jill M.; Erickson, Ken L.

    2014-12-09

    In this study, polymer foam encapsulants provide mechanical, electrical, and thermal isolation in engineered systems. It can be advantageous to surround objects of interest, such as electronics, with foams in a hermetically sealed container in order to protect them from hostile environments or from accidents such as fire. In fire environments, gas pressure from thermal decomposition of foams can cause mechanical failure of sealed systems. In this work, a detailed uncertainty quantification study of polymeric methylene diisocyanate (PMDI)-polyether-polyol based polyurethane foam is presented and compared to experimental results to assess the validity of a 3-D finite element model of themore » heat transfer and degradation processes. In this series of experiments, 320 kg/m3 PMDI foam in a 0.2 L sealed steel container is heated to 1,073 K at a rate of 150 K/min. The experiment ends when the can breaches due to the buildup of pressure. The temperature at key location is monitored as well as the internal pressure of the can. Both experimental uncertainty and computational uncertainty are examined and compared. The mean value method (MV) and Latin hypercube sampling (LHS) approach are used to propagate the uncertainty through the model. The results of the both the MV method and the LHS approach show that while the model generally can predict the temperature at given locations in the system, it is less successful at predicting the pressure response. Also, these two approaches for propagating uncertainty agree with each other, the importance of each input parameter on the simulation results is also investigated, showing that for the temperature response the conductivity of the steel container and the effective conductivity of the foam, are the most important parameters. For the pressure response, the activation energy, effective conductivity, and specific heat are most important. The comparison to experiments and the identification of the drivers of uncertainty allow for

  6. ACTUAL-WASTE TESTS OF ENHANCED CHEMICAL CLEANING FOR RETRIEVAL OF SRS HLW SLUDGE TANK HEELS AND DECOMPOSITION OF OXALIC ACID

    SciTech Connect (OSTI)

    Martino, C.; King, W.; Ketusky, E.

    2012-01-12

    Savannah River National Laboratory conducted a series of tests on the Enhanced Chemical Cleaning (ECC) process using actual Savannah River Site waste material from Tanks 5F and 12H. Testing involved sludge dissolution with 2 wt% oxalic acid, the decomposition of the oxalates by ozonolysis (with and without the aid of ultraviolet light), the evaporation of water from the product, and tracking the concentrations of key components throughout the process. During ECC actual waste testing, the process was successful in decomposing oxalate to below the target levels without causing substantial physical or chemical changes in the product sludge.

  7. Synthesis and characterization of ZnO and Ni doped ZnO nanorods by thermal decomposition method for spintronics application

    SciTech Connect (OSTI)

    Saravanan, R.; Santhi, Kalavathy; Sivakumar, N.; Narayanan, V.; Stephen, A.

    2012-05-15

    Zinc oxide nanorods and diluted magnetic semiconducting Ni doped ZnO nanorods were prepared by thermal decomposition method. This method is simple and cost effective. The decomposition temperature of acetate and formation of oxide were determined by TGA before the actual synthesis process. The X-ray diffraction result indicates the single phase hexagonal structure of zinc oxide. The transmission electron microscopy and scanning electron microscopy images show rod like structure of ZnO and Ni doped ZnO samples with the diameter {approx} 35 nm and the length in few micrometers. The surface analysis was performed using X-ray photoelectron spectroscopic studies. The Ni doped ZnO exhibits room temperature ferromagnetism. This diluted magnetic semiconducting Ni doped ZnO nanorods finds its application in spintronics. - Highlights: Black-Right-Pointing-Pointer The method used is very simple and cost effective compared to all other methods for the preparation DMS materials. Black-Right-Pointing-Pointer ZnO and Ni doped ZnO nanorods Black-Right-Pointing-Pointer Ferromagnetism at room temperature.

  8. Catalyst Activity and Post-operation Analyses of Pt/TiO2 (Rutile) Catalysts Used in the Sulfuric Acid Decomposition Reaction

    SciTech Connect (OSTI)

    Lucia M. Petkovic; Daniel M. Ginosar; Harry W. Rollins; Kyle C. Burch; Patrick J. Pinhero; Helen H. Farrell

    2007-06-01

    Production of hydrogen by splitting of water at lower temperatures than by direct thermal decomposition can be achieved by a series of particular chemical reactions that establish a thermochemical cycle [1]. Among the high number of thermochemical water-splitting cycles proposed in the literature [2], the sulfur-based group is of considerable interest. All the sulfur-based cycles employ the catalytic decomposition of sulfuric acid into SO2 and O2. The produced O2 corresponds to the O2 generated from water in the overall cycle. Research performed at the Idaho National Laboratory [3] has found that even one of the most stables catalysts, Pt supported on low surface area titania, deactivates with time on stream (TOS). To develop an understanding of the factors that cause catalyst deactivation, samples of 1% Pt supported on titania (rutile) catalyst were submitted to flowing concentrated sulfuric acid at 1123 K and atmospheric pressure for different TOSs between 0 and 548 h and a number of chemical and spectroscopic analyses applied to the spent samples.

  9. The thermal decomposition of NH{sub 2}OH and subsequent reactions : ab initio transition state theory and reflected shock tube experiments.

    SciTech Connect (OSTI)

    Klippenstein, S. J.; Harding, L. B.; Ruscic, B.; Sivaramakrishnan, R.; Srinivasan, N. K.; Su, M.-C.; Michael, J. V.; Chemical Sciences and Engineering Division; Sonoma State Univ.

    2009-01-01

    Primary and secondary reactions involved in the thermal decomposition of NH{sub 2}OH are studied with a combination of shock tube experiments and transition state theory based theoretical kinetics. This coupled theory and experiment study demonstrates the utility of NH{sub 2}OH as a high temperature source of OH radicals. The reflected shock technique is employed in the determination of OH radical time profiles via multipass electronic absorption spectrometry. O-atoms are searched for with atomic resonance absorption spectrometry. The experiments provide a direct measurement of the rate coefficient, k{sub 1}, for the thermal decomposition of NH{sub 2}OH. Secondary rate measurements are obtained for the NH{sub 2} + OH (5a) and NH{sub 2}OH + OH (6a) abstraction reactions. The experimental data are obtained for temperatures in the range from 1355 to 1889 K and are well represented by the respective rate expressions: log[k/(cm{sup 3} molecule{sup -1} s{sup -1})] = (?10.12 {+-} 0.20) + (?6793 {+-} 317 K/T) (k{sub 1}); log[k/(cm{sup 3} molecule{sup -1} s{sup -1})] = (?10.00 {+-} 0.06) + (?879 {+-} 101 K/T) (k{sub 5a}); log[k/(cm{sup 3} molecule{sup -1} s{sup -1})] = (?9.75 {+-} 0.08) + (?1248 {+-} 123 K/T) (k{sub 6a}). Theoretical predictions are made for these rate coefficients as well for the reactions of NH{sub 2}OH + NH{sub 2}, NH{sub 2}OH + NH, NH + OH, NH{sub 2} + NH{sub 2}, NH{sub 2} + NH, and NH + NH, each of which could be of secondary importance in NH{sub 2}OH thermal decomposition. The theoretical analyses employ a combination of ab initio transition state theory and master equation simulations. Comparisons between theory and experiment are made where possible. Modest adjustments of predicted barrier heights (i.e., by 2 kcal/mol or less) generally yield good agreement between theory and experiment. The rate coefficients obtained here should be of utility in modeling NO{sub x} in various combustion environments.

  10. Effect of internal noise on the oscillation of N{sub 2}O decomposition over Cu-ZSM-5 zeolites using a stochastic description

    SciTech Connect (OSTI)

    Liu, Fuliang; Li, Yaping Sun, Xiaoming

    2014-01-28

    When considering stochastic oscillations of heterogeneous catalyst systems, most researches have focused on the surface of a metal or its oxide catalysts, but there have been few studies on porous catalysts. In this work, the effects of internal noise on oscillations of N{sub 2}O decomposition over Cu-ZSM-5 zeolites are investigated, using the chemical Langevin equation and a mesoscopic stochastic model. Considering that Cu-ZSM-5 particles are finely divided particles, the number of Cu ions (N{sub s}) is proportional to the particle size at a certain Cu/Al, and the internal noise is inversely proportional to N{sub s}. Stochastic oscillations can be observed outside the deterministic oscillatory region. Furthermore, the performance of the oscillation characterized by the signal-to-noise ratio has a maximum within the optimal size range of 48 nm. This suggests that a nanometer-sized zeolite may be best for oscillations.

  11. Investigation of the Decomposition Mechanism of Lithium Bis(oxalate)borate (LiBOB) Salt in the Electrolyte of an Aprotic LiO2 Battery

    SciTech Connect (OSTI)

    Lau, Kah Chun; Lu, Jun; Low, John; Peng, Du; Wu, Huiming; Albishri, Hassan M.; Al-Hady, D. Abd; Curtiss, Larry A.; Amine, Khalil

    2014-04-01

    The stability of the lithium bis(oxalate) borate (LiBOB) salt against lithium peroxide (Li2O2) formation in an aprotic LiO2 (Liair) battery is investigated. From theoretical and experimental findings, we find that the chemical decomposition of LiBOB in electrolytes leads to the formation lithium oxalate during the discharge of a LiO2 cell. According to density functional theory (DFT) calculations, the formation of lithium oxalate as the reaction product is exothermic and therefore is thermodynamically feasible. This reaction seems to be independent of solvents used in the LiO2 cell, and therefore LiBOB is probably not suitable to be used as the salt in LiO2 cell electrolytes.

  12. Stimulated decomposition of Fe(OH)[sub 2] in the presence of AVT chemicals and metallic surfaces - Relevance to low-temperature feedwater line corrosion

    SciTech Connect (OSTI)

    Joshi, P.S.; Venkateswaran, G.; Venkateswarlu, K.S.; Rao, K.A. )

    1993-04-01

    Alkalizing agents cyclohexylamine, morpholine, and hydrazine accelerate the base-induced decomposition of Fe(OH)[sub 2] even at high pH levels by lowering the activation energy of the reaction. Efficient evolution of hydrogen is observed from Fe(OH)[sub 2] suspension in the presence of hydrazine, while weakly stimulated evolution is observed in the presence of cyclohexylamine and morpholine. It appears that the concentration and complexing abilities of the additives critically determine the yield of hydrogen. Nickel-containing surfaces such as NiO and Monel 400 alloy (UNS N04400) apart from pure nickel also increase the H[sub 2] yield from Fe(OH)[sub 2] suspensions. These observations are related to corrosion occurring in the low-temperature portion of feedwater circuits of power plants.

  13. Rate constants for the thermal decomposition of ethanol and its bimolecular reactions with OH and D : reflected shock tube and theoretical studies.

    SciTech Connect (OSTI)

    Sivaramakrishnan, R.; Su, M.-C.; Michael, J. V.; Klippenstein, S. J.; Harding, L. B.; Ruscic, B.

    2010-09-09

    The thermal decomposition of ethanol and its reactions with OH and D have been studied with both shock tube experiments and ab initio transition state theory-based master equation calculations. Dissociation rate constants for ethanol have been measured at high T in reflected shock waves using OH optical absorption and high-sensitivity H-atom ARAS detection. The three dissociation processes that are dominant at high T are: C{sub 2}H{sub 5}OH {yields} C{sub 2}H{sub 4} + H{sub 2}O; C{sub 2}H{sub 5}OH {yields} CH{sub 3} + CH{sub 2}OH; C{sub 2}H{sub 5}OH {yields} C{sub 2}H{sub 5} + OH. The rate coefficient for reaction C was measured directly with high sensitivity at 308 nm using a multipass optical White cell. Meanwhile, H-atom ARAS measurements yield the overall rate coefficient and that for the sum of reactions B and C, since H-atoms are instantaneously formed from the decompositions of CH{sub 2}OH and C{sub 2}H{sub 5} into CH{sub 2}O + H and C{sub 2}H{sub 4} + H, respectively. By difference, rate constants for reaction 1 could be obtained. One potential complication is the scavenging of OH by unreacted ethanol in the OH experiments, and therefore, rate constants for OH + C{sub 2}H{sub 5}OH {yields} products were measured using tert-butyl hydroperoxide (tBH) as the thermal source for OH. The present experiments can be represented by the Arrhenius expression k = (2.5 {+-} 0.43) x 10{sup -11} exp(- 911 {+-} 191 K/T) cm{sup 3} molecule{sup -1} s{sup -1} over the T range 857-1297 K. For completeness, we have also measured the rate coefficient for the reaction of D atoms with ethanol D + C{sub 2}H{sub 5}OH {yields} products whose H analogue is another key reaction in the combustion of ethanol. Over the T range 1054-1359 K, the rate constants from the present experiments can be represented by the Arrhenius expression, k = (3.98 {+-} 0.76) x 10{sup -10} exp(- 4494 {+-} 235 K/T) cm{sup 3} molecule{sup -1} s{sup -1}. The high-pressure rate coefficients for reactions B and C

  14. Meso/macroporous {gamma}-Al{sub 2}O{sub 3} fabricated by thermal decomposition of nanorods ammonium aluminium carbonate hydroxide

    SciTech Connect (OSTI)

    Li, Guang-Ci; Liu, Yun-Qi; Guan, Li-Li; Hu, Xiao-Fu; Liu, Chen-Guang

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Rod-like AACH were synthesized by a hydrothermal treatment. Black-Right-Pointing-Pointer AACH was formed via a Al(OH){sub 3} {yields} (NH{sub 4}){sub 2}Al{sub 6}(CO{sub 3}){sub 3}(OH){sub 14}{center_dot}xH{sub 2}O {yields} NH{sub 4}Al(OH){sub 2}CO{sub 3}{center_dot}H{sub 2}O {yields} NH{sub 4}Al(OH){sub 2}CO{sub 3} path. Black-Right-Pointing-Pointer Alumina derived from AACH has a good thermal stability. Black-Right-Pointing-Pointer The obtained alumina possesses large pore volume and bimodal porosity. -- Abstract: Through exploring the reaction parameters during the synthesis of the AACH, rod-like ammonium aluminium carbonate hydroxide (AACH) with high crystallinity has been successfully prepared via a facile hydrothermal method. The synthesis parameters like time, the molar ratio of NH{sub 4}HCO{sub 3}/Al and the properties of starting materials were systematically investigated. The structure was characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), IR and transmission electron microscopy (TEM). The experimental results display that the obtained {gamma}-Al{sub 2}O{sub 3} materials possess meso/macroporosity and large pore volume, which are mainly attributed to the removal of gas molecules during the decomposition of AACH. Moreover, using the rod-like AACH as precursor, {gamma}-Al{sub 2}O{sub 3} nanorods were obtained via a low-temperature thermal decomposition method.

  15. The role of adsorption in decomposition of dyes on TiO{sub 2} and N-modified TiO{sub 2} photocatalysts under UV and visible light irradiations

    SciTech Connect (OSTI)

    Bubacz, Kamila; Tryba, Beata; Morawski, Antoni W.

    2012-11-15

    Graphical abstract: Influence of pH and zeta potential of TiO{sub 2} based photocatalysts on the adsorption and degradation of MB under UV irradiation. Highlights: ? Adsorption of dyes on TiO{sub 2}/N accelerated their decomposition under visible light. ? pH of solution and the PZC of the TiO{sub 2} surface influence the adsorption of dyes. ? Under UV irradiation oxidation of pollutants with OH radicals is the most powerful. -- Abstract: Photoactivities of TiO{sub 2} based photocatalysts towards dyes decomposition was studied by consider their adsorption abilities. It was proved that zeta potential and PZC (point zero charge) of photocatalyst surface as well as pH of solution strongly influenced adsorption of tested dyes, Methylene Blue (MB) and Reactive Red 198 (RR198). These dyes underwent the photocatalytic decomposition by two ways, OH radicals attack and direct oxidation with photogenerated holes. The latter one is more efficient in case of better contact of pollutant with the photocatalysts surface and is dominant under visible light irradiation, where insignificant amount of OH radicals is formed. The former one is powerful under UV irradiation and is a key factor in decomposition of dyes regardless of their adsorption abilities.

  16. Methanol Decomposition over Palladium Particles Supported on Silica: Role of Particle Size and Co-Feeding Carbon Dioxide on the Catalytic Properties

    SciTech Connect (OSTI)

    Hokenek, Selma; Kuhn, John N. (USF)

    2012-10-23

    Monodisperse palladium particles of six distinct and controlled sizes between 4-16 nm were synthesized in a one-pot polyol process by varying the molar ratios of the two palladium precursors used, which contained palladium in different oxidation states. This difference permitted size control by regulation of the nucleation rate because low oxidation state metals ions nucleate quickly relative to high oxidation state ions. After immobilization of the Pd particles on silica by mild sonication, the catalysts were characterized by X-ray absorption spectroscopy and applied toward catalytic methanol decomposition. This reaction was determined as structure sensitive with the intrinsic activity (turnover frequency) increasing with increasing particle size. Moreover, observed catalytic deactivation was linked to product (carbon monoxide) poisoning. Co-feeding carbon dioxide caused the activity and the amount of deactivation to decrease substantially. A reaction mechanism based on the formation of the {pi}-bond between carbon and oxygen as the rate-limiting step is in agreement with antipathetic structure sensitivity and product poisoning by carbon monoxide.

  17. Silver-mordenite for radiologic gas capture from complex streams. Dual catalytic CH3I decomposition and I confinement

    SciTech Connect (OSTI)

    Nenoff, Tina M.; Rodriguez, Mark A.; Soelberg, Nick R.; Chapman, Karena W.

    2014-05-09

    The selective capture of radiological iodine (129I) is a persistent concern for safe nuclear energy. In these nuclear fuel reprocessing scenarios, the gas streams to be treated are extremely complex, containing several distinct iodine-containing molecules amongst a large variety of other species. Silver-containing mordenite (MOR) is a longstanding benchmark for radioiodine capture, reacting with molecular iodine (I2) to form AgI. However the mechanisms for organoiodine capture is not well understood. Here we investigate the capture of methyl iodide from complex mixed gas streams by combining chemical analysis of the effluent gas stream with in depth characterization of the recovered sorbent. Tools applied include infrared spectroscopy, thermogravimetric analysis with mass spectrometry, micro X-ray fluorescence, powder X-ray diffraction analysis, and pair distribution function analysis. Moreover, the MOR zeolite catalyzes decomposition of the methyl iodide through formation of surface methoxy species (SMS), which subsequently reacts with water in the mixed gas stream to form methanol, and with methanol to form dimethyl ether, which are both detected downstream in the effluent. The liberated iodine reacts with Ag in the MOR pore to the form subnanometer AgI clusters, smaller than the MOR pores, suggesting that the iodine is both physically and chemically confined within the zeolite.

  18. A pseudo-spectral method for the simulation of poro-elastic seismic wave propagation in 2D polar coordinates using domain decomposition

    SciTech Connect (OSTI)

    Sidler, Rolf, E-mail: rsidler@gmail.com [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland)] [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland); Carcione, Jos M. [Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42c, 34010 Sgonico, Trieste (Italy)] [Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42c, 34010 Sgonico, Trieste (Italy); Holliger, Klaus [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland)] [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland)

    2013-02-15

    We present a novel numerical approach for the comprehensive, flexible, and accurate simulation of poro-elastic wave propagation in 2D polar coordinates. An important application of this method and its extensions will be the modeling of complex seismic wave phenomena in fluid-filled boreholes, which represents a major, and as of yet largely unresolved, computational problem in exploration geophysics. In view of this, we consider a numerical mesh, which can be arbitrarily heterogeneous, consisting of two or more concentric rings representing the fluid in the center and the surrounding porous medium. The spatial discretization is based on a Chebyshev expansion in the radial direction and a Fourier expansion in the azimuthal direction and a RungeKutta integration scheme for the time evolution. A domain decomposition method is used to match the fluidsolid boundary conditions based on the method of characteristics. This multi-domain approach allows for significant reductions of the number of grid points in the azimuthal direction for the inner grid domain and thus for corresponding increases of the time step and enhancements of computational efficiency. The viability and accuracy of the proposed method has been rigorously tested and verified through comparisons with analytical solutions as well as with the results obtained with a corresponding, previously published, and independently benchmarked solution for 2D Cartesian coordinates. Finally, the proposed numerical solution also satisfies the reciprocity theorem, which indicates that the inherent singularity associated with the origin of the polar coordinate system is adequately handled.

  19. Public Interest Energy Research (PIER) Program. Final Project Report. California Energy Balance Update and Decomposition Analysis for the Industry and Building Sectors

    SciTech Connect (OSTI)

    de la Rue du Can, Stephane; Hasanbeigi, Ali; Sathaye, Jayant

    2010-12-01

    This report on the California Energy Balance version 2 (CALEB v2) database documents the latest update and improvements to CALEB version 1 (CALEB v1) and provides a complete picture of how energy is supplied and consumed in the State of California. The CALEB research team at Lawrence Berkeley National Laboratory (LBNL) performed the research and analysis described in this report. CALEB manages highly disaggregated data on energy supply, transformation, and end-use consumption for about 40 different energy commodities, from 1990 to 2008. This report describes in detail California's energy use from supply through end-use consumption as well as the data sources used. The report also analyzes trends in energy demand for the "Manufacturing" and "Building" sectors. Decomposition analysis of energy consumption combined with measures of the activity driving that consumption quantifies the effects of factors that shape energy consumption trends. The study finds that a decrease in energy intensity has had a very significant impact on reducing energy demand over the past 20 years. The largest impact can be observed in the industry sector where energy demand would have had increased by 358 trillion British thermal units (TBtu) if subsectoral energy intensities had remained at 1997 levels. Instead, energy demand actually decreased by 70 TBtu. In the "Building" sector, combined results from the "Service" and "Residential" subsectors suggest that energy demand would have increased by 264 TBtu (121 TBtu in the "Services" sector and 143 TBtu in the "Residential" sector) during the same period, 1997 to 2008. However, energy demand increased at a lesser rate, by only 162 TBtu (92 TBtu in the "Services" sector and 70 TBtu in the "Residential" sector). These energy intensity reductions can be indicative of energyefficiency improvements during the past 10 years. The research presented in this report provides a basis for developing an energy-efficiency performance index to measure

  20. THERMAL DECOMPOSITION OF URANIUM COMPOUNDS

    DOE Patents [OSTI]

    Magel, T.T.; Brewer, L.

    1959-02-10

    A method is presented of preparing uranium metal of high purity consisting contacting impure U metal with halogen vapor at between 450 and 550 C to form uranium halide vapor, contacting the uranium halide vapor in the presence of H/sub 2/ with a refractory surface at about 1400 C to thermally decompose the uranium halides and deposit molten U on the refractory surface and collecting the molten U dripping from the surface. The entire operation is carried on at a sub-atmospheric pressure of below 1 mm mercury.

  1. Collaborative Research: Process-Resolving Decomposition of the Global Temperature Response to Modes of Low Frequency Variability in a Changing Climate

    SciTech Connect (OSTI)

    Deng, Yi

    2014-11-24

    DOE-GTRC-05596 11/24/2104 Collaborative Research: Process-Resolving Decomposition of the Global Temperature Response to Modes of Low Frequency Variability in a Changing Climate PI: Dr. Yi Deng (PI) School of Earth and Atmospheric Sciences Georgia Institute of Technology 404-385-1821, yi.deng@eas.gatech.edu El Niño-Southern Oscillation (ENSO) and Annular Modes (AMs) represent respectively the most important modes of low frequency variability in the tropical and extratropical circulations. The projection of future changes in the ENSO and AM variability, however, remains highly uncertain with the state-of-the-science climate models. This project conducted a process-resolving, quantitative evaluations of the ENSO and AM variability in the modern reanalysis observations and in climate model simulations. The goal is to identify and understand the sources of uncertainty and biases in models’ representation of ENSO and AM variability. Using a feedback analysis method originally formulated by one of the collaborative PIs, we partitioned the 3D atmospheric temperature anomalies and surface temperature anomalies associated with ENSO and AM variability into components linked to 1) radiation-related thermodynamic processes such as cloud and water vapor feedbacks, 2) local dynamical processes including convection and turbulent/diffusive energy transfer and 3) non-local dynamical processes such as the horizontal energy transport in the oceans and atmosphere. In the past 4 years, the research conducted at Georgia Tech under the support of this project has led to 15 peer-reviewed publications and 9 conference/workshop presentations. Two graduate students and one postdoctoral fellow also received research training through participating the project activities. This final technical report summarizes key scientific discoveries we made and provides also a list of all publications and conference presentations resulted from research activities at Georgia Tech. The main findings include

  2. Short time proton dynamics in bulk ice and in porous anode solid oxide fuel cell materials

    SciTech Connect (OSTI)

    Basoli, Francesco; Senesi, Roberto; Kolesnikov, Alexander I; Licoccia, Silvia

    2014-01-01

    Oxygen reduction and incorporation into solid electrolytes and the reverse reaction of oxygen evolution play a cru-cial role in Solid Oxide Fuel Cell (SOFC) applications. However a detailed un derstanding of the kinetics of the cor-responding reactions, i.e. on reaction mechanisms, rate limiting steps, reaction paths, electrocatalytic role of materials, is still missing. These include a thorough characterization of the binding potentials experienced by protons in the lattice. We report results of Inelastic Neutron Scattering (INS) measurements of the vibrational state of the protons in Ni- YSZ highly porous composites (75% to 90% ), a ceramic-metal material showing a high electrical conductivity and ther mal stability, which is known to be most effectively used as anodes for solid ox ide fuel cells. The results are compared with INS and Deep Inelastic Neutron Scattering (DINS) experiments on the proton binding states in bulk ice.

  3. Investigation of the physical properties of the tetragonal CeMAl4Si2...

    Office of Scientific and Technical Information (OSTI)

    You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This ... The synthesis, crystal structure and physical properties studied by means of x-ray ...

  4. The influence of the iron content on the reductive decomposition of A{sub 3?x}Fe{sub x}Al{sub 2}Si{sub 3}O{sub 12} garnets (A = Mg, Mn; 0.47 ? x ? 2.85)

    SciTech Connect (OSTI)

    Aparicio, Claudia, E-mail: claudia.aparicio@upol.cz; Filip, Jan, E-mail: claudia.aparicio@upol.cz; Mashlan, Miroslav, E-mail: claudia.aparicio@upol.cz; Zboril, Radek, E-mail: claudia.aparicio@upol.cz [Regional Centre of Advanced Technologies and Materials, Departments of Experimental Physics and Physical Chemistry, Faculty of Science, Palacky University, 17. listopadu 1192/12, 77146 Olomouc (Czech Republic)

    2014-10-27

    Thermally-induced reductive decomposition of natural iron-bearing garnets of the almandine-pyrope and almandine-spessartine series were studied at temperatures up to 1200 C (heating rate of 10 C/min) under atmosphere of forming gas (10% of H{sub 2} in N{sub 2}). Crystallochemical formula of the studied garnet was calculated as {sup VIII}(A{sub 3?x}Fe{sub x}{sup 2+}){sup VI}(Al,Fe{sup 3+}){sub 2}Si{sub 3}O{sub 12}, where the amount of Fe{sup 3+} in the octahedral sites is negligible with the exception of pyrope, A = Mg, Mn, and 0.47 ? x ? 2.85. The observed decomposition temperature, determined from differential scanning calorimetry and thermogravimetry, is greater than 1000 C in all cases and showed almost linear dependence on the iron content in the dodecahedral sites of the studied garnets, with the exception of garnet with a near-pyrope composition (Prp{sub 80}Alm{sub 20}). The initial garnet samples and decomposition products were characterized in details by means of X-ray powder diffraction and {sup 57}Fe Mssbauer spectroscopy. We found that all studied garnets have common decomposition products such as metallic iron (in general, rounded particles below 4 ?m) and Fe-spinel; the other identified decomposition products depend on starting chemical composition of the garnet: Fe-cordierite, olivine (fayalite or tephroite), cristobalite, pyroxene (enstatite or pigeonite), and anorthite. Anorthite and pigeonite were only present in garnets with Ca in the dodecahedral site. All the identified phases were usually well crystallized.

  5. Longitudinal spin Seebeck effect in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} prepared on gadolinium gallium garnet (001) by metal organic decomposition method

    SciTech Connect (OSTI)

    Asada, H. Kuwahara, A.; Sakata, N.; Ono, T.; Kishimoto, K.; Koyanagi, T.; Ishibashi, T.; Meguro, A.; Hashinaka, T.

    2015-05-07

    Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} thin films with the Ga composition x = 0, 0.5, and 1.0 are prepared on (001) oriented gadolinium gallium garnet substrates by a metal organic decomposition method. Only (001) peaks are observed in x-ray diffraction patterns for all the films, suggesting that the highly oriented Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} thin films were formed. Increasing Ga composition, the saturation magnetization decreases, and the perpendicular easy axis is enhanced due to the decrease of the shape anisotropy. Longitudinal spin Seebeck effects (LSSEs) in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} thin films with a Pt layer of 10 nm in thickness were investigated. Magnetic field dependence of the thermoelectric voltage caused by the LSSE in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} films indicates the hysteresis loop with the small coercivity reflecting the magnetization curve. The decrease of LSSE voltage in Nd{sub 2}BiFe{sub 5−x}Ga{sub x}O{sub 12} is clearly observed with the decrease of Fe composition.

  6. Thermoelectric and microstructural properties of Pb{sub 0.9-x}Sn{sub 0.1}Ge{sub x}Te compounds prepared by spinodal decomposition

    SciTech Connect (OSTI)

    Sondergaard, M.; Christensen, M.; Johnsen, S. [Center for Energy Materials, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C (Denmark); Stiewe, C.; Dasgupta, T.; Mueller, E. [German Aerospace Center (DLR), Linder Hoehe, DE-51147 Cologne (Germany); Iversen, B.B., E-mail: bo@chem.au.d [Center for Energy Materials, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C (Denmark)

    2011-05-15

    Three samples of Pb{sub 0.9-x}Sn{sub 0.1}Ge{sub x}Te with x=0.25, 0.35, 0.6 were prepared by heating the mixtures above the melting point of the constituent elements followed by quenching in water. The x=0.6 sample is close to the center of the immiscibility region, while the x=0.25 and 0.35 samples are in the Pb rich region inside the spinodal miscibility gap. Microstructural investigations using Powder X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy revealed both GeTe-rich and PbTe-rich phases. The samples were uniaxially hot pressed and the thermoelectric properties were characterized in the temperature range 2-400 K using a commercial apparatus and from 300 to 650 K with a custom designed setup. The best sample (x=0.6) reached zT{approx}0.6 at 650 K, while the x=0.25 and 0.35 samples showed thermal instability at elevated temperatures. -- Graphical abstract: Spinodal decomposition in the GeTe-SnTe-PbTe system demonstrated by SEM and EXS images. Display Omitted Highlights: {yields} Investigation of Pb-rich part of the spinodal miscibility gap in PbTe-SnTe-GeTe. {yields} zT=0.6 at 650 K reproduced for Pb{sub 0.3}Sn{sub 0.1}Ge{sub 0.6}Te. {yields} Pb-rich phases shown to be thermally instable. {yields} Thermoelectric property characterization at low and high temperature. {yields} Microstructural investigations using PXRD, SEM, EDX and PSM.

  7. Plutonium Hexafluoride Thermal Decomposition Rates (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Find in Google Scholar Find in Google Scholar Search WorldCat Search WorldCat to find libraries that may hold this journal Have feedback or suggestions for a way to improve these ...

  8. Task Decomposition in Human Reliability Analysis

    SciTech Connect (OSTI)

    Boring, Ronald Laurids; Joe, Jeffrey Clark

    2014-06-01

    In the probabilistic safety assessments (PSAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approaches should arrive at the same set of HFEs. This question remains central as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PSAs tend to be top-down— defined as a subset of the PSA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) are more likely to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications.

  9. Method for thermochemical decomposition of water

    DOE Patents [OSTI]

    Abraham, Bernard M.; Schreiner, Felix

    1977-01-11

    Water is thermochemically decomposed to produce hydrogen by the following sequence of reactions: KI, NH.sub.3, CO.sub. 2 and water in an organic solvent such as ethyl or propyl alcohol are reacted to produce KHCO 3 and NH.sub.4 I. The KHCO.sub.3 is thermally decomposed to K.sub.2 CO.sub.3, H.sub.2 O and CO.sub.2, while the NH.sub.4 I is reacted with Hg to produce HgI.sub.2, NH.sub.3 and H.sub.2. The K.sub.2 CO.sub.3 obtained by calcining KHCO.sub.3 is then reacted with HgI.sub.2 to produce Hg, KI, CO and O.sub.2. All products of the reaction are recycled except hydrogen and oxygen.

  10. Rexsss Performance Analysis: Domain Decomposition Algorithm Implementa...

    Office of Scientific and Technical Information (OSTI)

    Close Cite: Bibtex Format Close 0 pages in this document matching the terms "" Search For Terms: Enter terms in the toolbar above to search the full text of this document for ...

  11. The Natural Helmholtz-Hodge Decomposition

    Energy Science and Technology Software Center (OSTI)

    2015-08-20

    nHHD is a C++ library to decompose a flow field into three components exhibiting specific types of behaviors. These components allow more targeted analysis of flow behavior and can be applied to a variety of application areas.

  12. Use of oxide decompositions in advanced thermochemical hydrogen cycles for solar heat sources. Experimental results on the low-temperature reactions for the tricobalt tetraoxide-cobalt monoxide pair

    SciTech Connect (OSTI)

    Jones, W.M.; Bowman, M.G.

    1982-01-01

    The concept of utilizing oxide decompositions in advanced thermochemical hydrogen cycles for solar heat sources is introduced. It has particular interest in allowing direct transmission of energy to the process through an air window. A cycle for the Co/sub 3/O/sub 4/-CoO pair would be, schematically: (1) Co/sub 3/O/sub 4/ = 3CoO + 1/2 O/sub 2/; (2) I/sub 2/(s,1) + Mg(OH)/sub 2/ + 3CoO = MgI/sub 2/(aq) + Co/sub 3/O/sub 4/ + H/sub 2/O(1); (3) H/sub 2/O + MgI/sub 2/(aq) = MgO + 2HI; (4) 2 HI = H/sub 2/ + I/sub 2/; (5) MgO + H/sub 2/O = Mg(OH)/sub 2/. Reaction (2) should give a high concentration of MgI/sub 2/ that would be favorable for (3). The solutions would also contain iodine dissolved as polyiodide, partly offsetting this advantage. Preliminary results indicate that reaction (2) is slow at 150/sup 0/C. It is surmised that the mechanism of (2) consists of the iodine disproportionation reaction (6), followed by reaction (7). (6) I/sub 2/(s,1) + Mg(OH)/sub 2/ = 5/6 MgI/sub 2/(aq) + 1/6 Mg(IO/sub 3/)/sub 2/(aq) + H/sub 2/O(1); (7) 1/6 Mg(IO/sub 3/)/sub 2/(aq) + 3 CoO = 1/6 MgI/sub 2/(aq) + Co/sub 3/O/sub 4/. Other workers have found (6) to be relatively fast and with a good yield at 150/sup 0/C. We have found the independently studied reaction (7) to be sufficiently slow at 150/sup 0/C to account for the slowness of (2). The yield of (7) was found to be proportional to the square root of the time, which suggests that iodate must diffuse through an adherent, accumulating Co/sub 3/O/sub 4/ layer. Since (7) is much faster when Mg(IO/sub 3/)/sub 2/ is replaced by KIO/sub 3/, the Mg/sup 2 +/ ion may catalyze formation of an adherent Co/sub 3/O/sub 4/ spinel layer. The reactivity of CoO in the KIO/sub 3/ analog of (7) is greatly decreased by exposure to high temperature.

  13. Method for increasing steam decomposition in a coal gasification process

    DOE Patents [OSTI]

    Wilson, Marvin W.

    1988-01-01

    The gasification of coal in the presence of steam and oxygen is significantly enhanced by introducing a thermochemical water-splitting agent such as sulfuric acid, into the gasifier for decomposing the steam to provide additional oxygen and hydrogen usable in the gasification process for the combustion of the coal and enrichment of the gaseous gasification products. The addition of the water-splitting agent into the gasifier also allows for the operation of the reactor at a lower temperature.

  14. Method for increasing steam decomposition in a coal gasification process

    DOE Patents [OSTI]

    Wilson, M.W.

    1987-03-23

    The gasification of coal in the presence of steam and oxygen is significantly enhanced by introducing a thermochemical water- splitting agent such as sulfuric acid, into the gasifier for decomposing the steam to provide additional oxygen and hydrogen usable in the gasification process for the combustion of the coal and enrichment of the gaseous gasification products. The addition of the water-splitting agent into the gasifier also allows for the operation of the reactor at a lower temperature.

  15. Domain decomposition in time for PDE-constrained optimization

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

    Barker, Andrew T.; Stoll, Martin

    2015-08-28

    Here, PDE-constrained optimization problems have a wide range of applications, but they lead to very large and ill-conditioned linear systems, especially if the problems are time dependent. In this paper we outline an approach for dealing with such problems by decomposing them in time and applying an additive Schwarz preconditioner in time, so that we can take advantage of parallel computers to deal with the very large linear systems. We then illustrate the performance of our method on a variety of problems.

  16. Method of generating hydrogen by catalytic decomposition of water

    DOE Patents [OSTI]

    Balachandran, Uthamalingam; Dorris, Stephen E.; Bose, Arun C.; Stiegel, Gary J.; Lee, Tae-Hyun

    2002-01-01

    A method for producing hydrogen includes providing a feed stream comprising water; contacting at least one proton conducting membrane adapted to interact with the feed stream; splitting the water into hydrogen and oxygen at a predetermined temperature; and separating the hydrogen from the oxygen. Preferably the proton conducting membrane comprises a proton conductor and a second phase material. Preferable proton conductors suitable for use in a proton conducting membrane include a lanthanide element, a Group VIA element and a Group IA or Group IIA element such as barium, strontium, or combinations of these elements. More preferred proton conductors include yttrium. Preferable second phase materials include platinum, palladium, nickel, cobalt, chromium, manganese, vanadium, silver, gold, copper, rhodium, ruthenium, niobium, zirconium, tantalum, and combinations of these. More preferably second phase materials suitable for use in a proton conducting membrane include nickel, palladium, and combinations of these. The method for generating hydrogen is preferably preformed in the range between about 600.degree. C. and 1,700.degree. C.

  17. Multigrid and multilevel domain decomposition for unstructured grids

    SciTech Connect (OSTI)

    Chan, T.; Smith, B.

    1994-12-31

    Multigrid has proven itself to be a very versatile method for the iterative solution of linear and nonlinear systems of equations arising from the discretization of PDES. In some applications, however, no natural multilevel structure of grids is available, and these must be generated as part of the solution procedure. In this presentation the authors will consider the problem of generating a multigrid algorithm when only a fine, unstructured grid is given. Their techniques generate a sequence of coarser grids by first forming an approximate maximal independent set of the vertices and then applying a Cavendish type algorithm to form the coarser triangulation. Numerical tests indicate that convergence using this approach can be as fast as standard multigrid on a structured mesh, at least in two dimensions.

  18. Decomposition of calcium sulfate: a review of the literature...

    Office of Scientific and Technical Information (OSTI)

    Authors: Swift, W M ; Panek, A F ; Smith, G W ; Vogel, G J ; Jonke, A A Publication Date: 1976-12-01 OSTI Identifier: 7224692 Report Number(s): ANL-76-122 DOE Contract Number: ...

  19. Thermal decomposition of silane to form hydrogenated amorphous Si

    DOE Patents [OSTI]

    Strongin, M.; Ghosh, A.K.; Wiesmann, H.J.; Rock, E.B.; Lutz, H.A. III

    Hydrogenated amorphous silicon is produced by thermally decomposing silane (SiH/sub 4/) or other gases comprising H and Si, at elevated temperatures of about 1700 to 2300/sup 0/C, in a vacuum of about 10/sup -8/ to 10/sup -4/ torr. A gaseous mixture is formed of atomic hydrogen and atomic silicon. The gaseous mixture is deposited onto a substrate to form hydrogenated amorphous silicon.

  20. Closed-form decomposition of one-loop massive amplitudes

    SciTech Connect (OSTI)

    Britto, Ruth; Feng Bo; Mastrolia, Pierpaolo

    2008-07-15

    We present formulas for the coefficients of 2-, 3-, 4-, and 5-point master integrals for one-loop massive amplitudes. The coefficients are derived from unitarity cuts in D dimensions. The input parameters can be read off from any unitarity-cut integrand, as assembled from tree-level expressions, after simple algebraic manipulations. The formulas presented here are suitable for analytical as well as numerical evaluation. Their validity is confirmed in two known cases of helicity amplitudes contributing to gg{yields}gg and gg{yields}gH, where the masses of the Higgs and the fermion circulating in the loop are kept as free parameters.

  1. Diverse Fungi Secrete Similar Suite of Decomposition Enzymes...

    Office of Science (SC) Website

    role in biofuel production and bioremediation of metal-contaminated soils and water. ... fungal species can be harnessed to remove toxic metals from contaminated soils and water. ...

  2. DECOMPOSITION OF CALCIUM SULFATE: A REVIEW OF THE LITERATURE

    Office of Scientific and Technical Information (OSTI)

    OF CALCIUM SULFATE: A REVIEW OF THE LITERATURE W. M. Swift, A. F. Panek, G. W. Smith, 0 . ... SULFATE : A REVIEW O F THE LITERATURE W. M. S w i f t , A. F. Panek, G. W. Smith, G . ...

  3. Ab initio kinetics and thermal decomposition mechanism of mononitrobiu...

    Office of Scientific and Technical Information (OSTI)

    Propellants Branch, Rocket Propulsion Division, Aerospace Systems Directorate, Air Force Research Laboratory, AFRLRQRP, 10 E. Saturn Blvd., Edwards AFB, California 93524, USA ...

  4. Pressure Dependent Decomposition Kinetics of the Energetic Material...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Country of Publication: United States Language: English Subject: 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ACCELERATION; DIAMONDS; KINETICS;...

  5. Spinodal Decomposition and Nucleation and Growth as a Means to...

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

    C. Uher, T. Hogan, M. G. Kanatzidis, et.al Year: 2007 Abstract: URL: Link to article - FTIR spectroscopy and Thermal Analysis labs Document: Download Document (PDF) - 6962.01kb...

  6. Integrated boiler, superheater, and decomposer for sulfuric acid decomposition

    DOE Patents [OSTI]

    Moore, Robert; Pickard, Paul S.; Parma, Jr., Edward J.; Vernon, Milton E.; Gelbard, Fred; Lenard, Roger X.

    2010-01-12

    A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.

  7. GSA Office of Governmentwide Policy CIVILIAN AGENCY ACQUISITION...

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

    N AG THER THAN NASA FROM: -LAURAAULETTA CHAIR CIVILIAN AGENCY ACQUISITION COUNCIL (CAAC) ... This CAAC memorandum constitutes consultation with the Chair of the CAAC required by FAR ...

  8. untitled

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

    ... The advanced accelerator and X-ray sources developed for this mission are being extended ... viscoelastic fric- tion to its potential energy, we developed a ther- modynamically ...

  9. Protermosolar | Open Energy Information

    Open Energy Info (EERE)

    Place: Sevilla, Spain Zip: 41092 Sector: Solar Product: Association of Solar Ther Electricity Generation (STEG) and equipment providers in Spain References:...

  10. Alliance to Save Energy | Open Energy Information

    Open Energy Info (EERE)

    Washington, DC Zip: 20036 Sector: Efficiency Product: String representation "Founded in 1977 ... ther countries." is too long. References: Alliance to Save Energy1 Information...

  11. Swatch Group | Open Energy Information

    Open Energy Info (EERE)

    Swatch Group Jump to: navigation, search Name: Swatch Group Place: Switzerland Product: String representation "The Swatch Grou ... ther industries" is too long. References: Swatch...

  12. GSA Office of Governmentwide Policy CIVILIAN AGENCY ACQUISITION...

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

    Office of Governmentwide Policy CIVILIAN AGENCY ACQUISITION LETTER 2013-03 May 7, 2013 MEMORANDUM FOR Cl N AG THER THAN NASA FROM: -LAURAAULETTA CHAIR CIVILIAN AGENCY ACQUISITION ...

  13. High Power Coax Window

    SciTech Connect (OSTI)

    Neubauer, M. L.; Dudas, A.; Sah, R.; Elliott, T. S.; Rimmer, R. A.; Stirbet, M. S.

    2010-05-23

    A su­per­con­duct­ing RF (SRF) power cou­pler ca­pa­ble of han­dling 500 kW CW RF power is re­quired for pre­sent and fu­ture stor­age rings and linacs. There are over 35 cou­pler de­signs for SRF cav­i­ties rang­ing in fre­quen­cy from 325 to 1500 MHz. Cou­pler win­dows vary from cylin­ders to cones to disks, and RF power cou­plers are lim­it­ed by the abil­i­ty of ce­ram­ic win­dows to with­stand the stress­es due to heat­ing and me­chan­i­cal flex­ure. We pro­pose a novel ro­bust co-ax­i­al SRF cou­pler de­sign which uses com­pressed win­dow tech­nol­o­gy. This tech­nol­o­gy will allow the use of high­ly ther­mal­ly con­duc­tive ma­te­ri­als for cryo­genic win­dows. Using com­pressed win­dow tech­niques on disk co-ax­i­al win­dows will make sig­nif­i­cant im­prove­ments in the power han­dling of SRF cou­plers. We pre­sent the bench test re­sults of two win­dow as­sem­blies back to back, as well as in­di­vid­u­al win­dow VSWR in EIA3.125 coax. A vac­u­um test as­sem­bly was made and the win­dows baked out at 155C. The pro­cess­es used to build win­dows is scal­able to larg­er di­am­e­ter coax and to high­er power lev­els.

  14. A Flow-Channel Analysis for the Mars Hopper

    SciTech Connect (OSTI)

    W. Spencer Cooley

    2013-02-01

    The Mars Hopper is an exploratory vehicle designed to fly on Mars using carbon dioxide from the Martian atmosphere as a rocket propellant. The propellent gasses are thermally heated while traversing a radioisotope ther- mal rocket (RTR) engine’s core. This core is comprised of a radioisotope surrounded by a heat capacitive material interspersed with tubes for the propellant to travel through. These tubes, or flow channels, can be manu- factured in various cross-sectional shapes such as a special four-point star or the traditional circle. Analytical heat transfer and computational fluid dynamics (CFD) anal- yses were performed using flow channels with either a circle or a star cross- sectional shape. The nominal total inlet pressure was specified at 2,805,000 Pa; and the outlet pressure was set to 2,785,000 Pa. The CO2 inlet tem- perature was 300 K; and the channel wall was 1200 K. The steady-state CFD simulations computed the smooth-walled star shape’s outlet temper- ature to be 959 K on the finest mesh. The smooth-walled circle’s outlet temperature was 902 K. A circle with a surface roughness specification at 0.01 mm gave 946 K and at 0.1 mm yielded 989 K. The The effects of a slightly varied inlet pressure were also examined. The analytical calculations were based on the mass flow rates computed in the CFD simulations and provided significantly higher outlet temperature results while displaying the same comparison trends. Research relating to the flow channel heat transfer studies was also done. Mathematical methods to geometrically match the cross-sectional areas of the circle and star, along with a square and equilateral triangle, were derived. A Wolfram Mathematica 8 module was programmed to analyze CFD results using Richardson Extrapolation and calculate the grid convergence index (GCI). A Mathematica notebook, also composed, computes and graphs the bulk mean temperature along a flow channel’s length while the user dynam- ically provides the input

  15. Fluctuation studies in the infinite interval matrix representations of operator products and their decompositions

    SciTech Connect (OSTI)

    Baykara, N. A.; Guervit, Ercan; Demiralp, Metin

    2012-12-10

    In this work a study on finite dimensional matrix approximations to products of quantum mechanical operators is conducted. It is emphasized that the matrix representation of the product of two operators is equal to the product of the matrix representation of each of the operators when all the fluctuation terms are ignored. The calculation of the elements of the matrices corresponding to the matrix representation of various operators, based on three terms recursive relation is defined. Finally it is shown that the approximation quality depends on the choice of higher values of n, namely the dimension of Hilbert space.

  16. One Size Does Not Fit All: Human Failure Event Decomposition and Task Analysis

    SciTech Connect (OSTI)

    Ronald Laurids Boring, PhD

    2014-09-01

    In the probabilistic safety assessments (PSAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered or exacerbated by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approaches should arrive at the same set of HFEs. This question remains central as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PSAs tend to be top-down—defined as a subset of the PSA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) are more likely to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications. In this paper, I first review top-down and bottom-up approaches for defining HFEs and then present a seven-step guideline to ensure a task analysis completed as part of human error identification decomposes to a level suitable for use as HFEs. This guideline illustrates an effective way to bridge the bottom-up approach with top-down requirements.

  17. A Linked-Cell Domain Decomposition Method for Molecular Dynamics Simulation on a Scalable Multiprocessor

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

    Yang, L. H.; Brooks III, E. D.; Belak, J.

    1992-01-01

    A molecular dynamics algorithm for performing large-scale simulations using the Parallel C Preprocessor (PCP) programming paradigm on the BBN TC2000, a massively parallel computer, is discussed. The algorithm uses a linked-cell data structure to obtain the near neighbors of each atom as time evoles. Each processor is assigned to a geometric domain containing many subcells and the storage for that domain is private to the processor. Within this scheme, the interdomain (i.e., interprocessor) communication is minimized.

  18. Overlapping domain decomposition preconditioners for the generalized Davidson method for the eigenvalue problem

    SciTech Connect (OSTI)

    Stathopoulos, A.; Fischer, C.F.; Saad, Y.

    1994-12-31

    The solution of the large, sparse, symmetric eigenvalue problem, Ax = {lambda}x, is central to many scientific applications. Among many iterative methods that attempt to solve this problem, the Lanczos and the Generalized Davidson (GD) are the most widely used methods. The Lanczos method builds an orthogonal basis for the Krylov subspace, from which the required eigenvectors are approximated through a Rayleigh-Ritz procedure. Each Lanczos iteration is economical to compute but the number of iterations may grow significantly for difficult problems. The GD method can be considered a preconditioned version of Lanczos. In each step the Rayleigh-Ritz procedure is solved and explicit orthogonalization of the preconditioned residual ((M {minus} {lambda}I){sup {minus}1}(A {minus} {lambda}I)x) is performed. Therefore, the GD method attempts to improve convergence and robustness at the expense of a more complicated step.

  19. Domain decomposition based iterative methods for nonlinear elliptic finite element problems

    SciTech Connect (OSTI)

    Cai, X.C.

    1994-12-31

    The class of overlapping Schwarz algorithms has been extensively studied for linear elliptic finite element problems. In this presentation, the author considers the solution of systems of nonlinear algebraic equations arising from the finite element discretization of some nonlinear elliptic equations. Several overlapping Schwarz algorithms, including the additive and multiplicative versions, with inexact Newton acceleration will be discussed. The author shows that the convergence rate of the Newton`s method is independent of the mesh size used in the finite element discretization, and also independent of the number of subdomains into which the original domain in decomposed. Numerical examples will be presented.

  20. Thermal decomposition of electronic wastes: Mobile phone case and other parts

    SciTech Connect (OSTI)

    Molto, Julia; Egea, Silvia; Conesa, Juan Antonio; Font, Rafael

    2011-12-15

    Highlights: > Pyrolysis and combustion of different parts of mobile phones produce important quantities of CO and CO{sub 2}. > Naphthalene is the most abundant PAH obtained in the thermal treatment of mobile phones. > Higher combustion temperature increases the chlorinated species evolved. - Abstract: Pyrolysis and combustion runs at 850 {sup o}C in a horizontal laboratory furnace were carried out on different parts of a mobile phone (printed circuit board, mobile case and a mixture of both materials). The analyses of the carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), polychlorodibenzo-p-dioxin, polychlorodibenzofurans (PCDD/Fs), and dioxin-like PCBs are shown. Regarding semivolatile compounds, phenol, styrene, and its derivatives had the highest yields. In nearly all the runs the same PAHs were identified, naphthalene being the most common component obtained. Combustion of the printed circuit board produced the highest emission factor of PCDD/Fs, possibly due to the high copper content.

  1. Proper Orthogonal Decomposition of the Flow in a T-Junction ...

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

    T-Junction (In: Advances in Nuclear Power Plants) Authors: Merzari, E., Pointer, W.D., ... Congress on Advances in Nuclear Power Plants 2010 (ICAPP 2010) Publisher: Curran ...

  2. Metatranscriptomic analysis of lignocellulolytic microbial communities involved in high-solids decomposition of rice straw

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

    Simmons, Christopher W.; Reddy, Amitha P.; D’haeseleer, Patrik; Khudyakov, Jane; Billis, Konstantinos; Pati, Amrita; Simmons, Blake A.; Singer, Steven W.; Thelen, Michael P.; VanderGheynst, Jean S.

    2014-12-31

    New lignocellulolytic enzymes are needed that maintain optimal activity under the harsh conditions present during industrial enzymatic deconstruction of biomass, including high temperatures, the absence of free water, and the presence of inhibitors from the biomass. Enriching lignocellulolytic microbial communities under these conditions provides a source of microorganisms that may yield robust lignocellulolytic enzymes tolerant to the extreme conditions needed to improve the throughput and efficiency of biomass enzymatic deconstruction. Identification of promising enzymes from these systems is challenging due to complex substrate-enzyme interactions and requirements to assay for activity. In this study, metatranscriptomes from compost-derived microbial communities enriched onmore » rice straw under thermophilic and mesophilic conditions were sequenced and analyzed to identify lignocellulolytic enzymes overexpressed under thermophilic conditions. To determine differential gene expression across mesophilic and thermophilic treatments, a method was developed which pooled gene expression by functional category, as indicated by Pfam annotations, since microbial communities performing similar tasks are likely to have overlapping functions even if they share no specific genes. Differential expression analysis identified enzymes from glycoside hydrolase family 48, carbohydrate binding module family 2, and carbohydrate binding module family 33 domains as significantly overexpressed in the thermophilic community. Overexpression of these protein families in the thermophilic community resulted from expression of a small number of genes not currently represented in any protein database. Genes in overexpressed protein families were predominantly expressed by a single Actinobacteria genus, Micromonospora. In conclusion, coupling measurements of deconstructive activity with comparative analyses to identify overexpressed enzymes in lignocellulolytic communities provides a targeted approach for discovery of candidate enzymes for more efficient biomass deconstruction. Furthermore, glycoside hydrolase family 48 cellulases and carbohydrate binding module family 33 polysaccharide monooxygenases with carbohydrate binding module family 2 domains may improve saccharification of lignocellulosic biomass under high-temperature and low moisture conditions relevant to industrial biofuel production.« less

  3. Estimation and decomposition of productive efficiency in a panel data model: an application to electric utilities

    SciTech Connect (OSTI)

    Melfi, C.A.

    1984-01-01

    New econometric methodology for modeling and estimating technical and allocative efficiency in production is proposed and applied. Translog cost frontier and share equations are presented in a panel data context, with the structure of the error terms representing noise and inefficiency. The use of panel data with this multivariate error components approach facilitates the separation of eficiency into its technical and allocative components, as well as the separation of noise from inefficiency. The model used is logically consistent in that the distributional assumptions concerning the disturbance vectors take into account the relationships among the disturbance terms in the cost and share equations. This method of efficiency measurement is applied to the electric utilities industry to obtain individual firm estimates of technical and allocative efficiency. The data consist of yearly cost, output, and input price information on 38 electric utility firms over a period of 18 years. Rate-of-return regulation in the electric utilities industry requires estimation of a regulated cost frontier and the associated share equations. Estimates of technical and allocative efficiency are obtained for each firm in every year. Comparisons are made with previous efficiency measurement studies. The measures of efficiency are analyzed in light of rate-of-return regulation.

  4. Mass-radius relations and core-envelope decompositions of super...

    Office of Scientific and Technical Information (OSTI)

    Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544 (United States) Department of Computer Science, Princeton University, Princeton, NJ ...

  5. Rapid hydrogen gas generation using reactive thermal decomposition of uranium hydride.

    SciTech Connect (OSTI)

    Kanouff, Michael P.; Van Blarigan, Peter; Robinson, David B.; Shugard, Andrew D.; Gharagozloo, Patricia E.; Buffleben, George M.; James, Scott Carlton; Mills, Bernice E.

    2011-09-01

    Oxygen gas injection has been studied as one method for rapidly generating hydrogen gas from a uranium hydride storage system. Small scale reactors, 2.9 g UH{sub 3}, were used to study the process experimentally. Complimentary numerical simulations were used to better characterize and understand the strongly coupled chemical and thermal transport processes controlling hydrogen gas liberation. The results indicate that UH{sub 3} and O{sub 2} are sufficiently reactive to enable a well designed system to release gram quantities of hydrogen in {approx} 2 seconds over a broad temperature range. The major system-design challenge appears to be heat management. In addition to the oxidation tests, H/D isotope exchange experiments were performed. The rate limiting step in the overall gas-to-particle exchange process was found to be hydrogen diffusion in the {approx}0.5 {mu}m hydride particles. The experiments generated a set of high quality experimental data; from which effective intra-particle diffusion coefficients can be inferred.

  6. Unconstrained plastering : all-hexahedral mesh generation via advancing front geometry decomposition (2004-2008).

    SciTech Connect (OSTI)

    Blacker, Teddy Dean; Staten, Matthew L.; Kerr, Robert A.; Owen, Steven James

    2010-03-01

    The generation of all-hexahedral finite element meshes has been an area of ongoing research for the past two decades and remains an open problem. Unconstrained plastering is a new method for generating all-hexahedral finite element meshes on arbitrary volumetric geometries. Starting from an unmeshed volume boundary, unconstrained plastering generates the interior mesh topology without the constraints of a pre-defined boundary mesh. Using advancing fronts, unconstrained plastering forms partially defined hexahedral dual sheets by decomposing the geometry into simple shapes, each of which can be meshed with simple meshing primitives. By breaking from the tradition of previous advancing-front algorithms, which start from pre-meshed boundary surfaces, unconstrained plastering demonstrates that for the tested geometries, high quality, boundary aligned, orientation insensitive, all-hexahedral meshes can be generated automatically without pre-meshing the boundary. Examples are given for meshes from both solid mechanics and geotechnical applications.

  7. Strain of alcaligenes latus bacteria used for the decomposition of polychlorinated biphenyls

    DOE Patents [OSTI]

    Dyadischev, Nikolai Romanovich; Zharikov, Gennady Alekseevich; Kapranov, Vladimir Vladimirovich

    2001-09-11

    Alcaligenes latus bacterial strain TXD-13 VKPM B 75-05 is capable of degrading polychlorinated biphenyls (PCBs). The strain may be employed to detoxicate environment media and PCB-containing industrial waste. To produce biomass, the strain is incubated on media which contain carbon sources, nitrogen sources and mineral salts. The strain is cultivated by a subsurface method up to a titer from 6.0.multidot.10.sup.8 to 2.0.times.10.sup.9 cells per cu cm. The produced biomass is used for degrading PCBs in concentrations from 10.sup.7 to 10.sup.8 cells per cu cm. The strain ensures from 35 to 50% reduction in PCB content in soil and water.

  8. Effect of Morphology of CdS thin film on the Photocatalytic Decomposition of Hydrogen Sulfide

    SciTech Connect (OSTI)

    Takahashi, A.; Ishiyama, T.; Takahashi, H.; Sato, Y.; Jeyadevan, B.; Tohji, K.

    2007-03-20

    Photocatalytic activity of the CdS thin film depended very much on the film density, adhesion between the CdS and substrate, and whether effective electron path existed or not. We have proposed the formation of a bridging layer of Cd metal to improve the film density, adhesivity and the electron conduction path. Here, we report the results of the study undertaken to develop CdS/Cd (dendrite)/Ti film with enhanced photocatalytic property to decompose hydrogen sulphide. CdS/Cd (dendrite)/Ti photocatalyst showed the highest photocatalytic activity and photocurrent, which was 1.4 times higher than the traditional CdS/Ti photocatalyst.

  9. Combinatorial evaluation of systems including decomposition of a system representation into fundamental cycles

    DOE Patents [OSTI]

    Oliveira, Joseph S.; Jones-Oliveira, Janet B.; Bailey, Colin G.; Gull, Dean W.

    2008-07-01

    One embodiment of the present invention includes a computer operable to represent a physical system with a graphical data structure corresponding to a matroid. The graphical data structure corresponds to a number of vertices and a number of edges that each correspond to two of the vertices. The computer is further operable to define a closed pathway arrangement with the graphical data structure and identify each different one of a number of fundamental cycles by evaluating a different respective one of the edges with a spanning tree representation. The fundamental cycles each include three or more of the vertices.

  10. Fourier decomposition of polymer orientation in large-amplitude oscillatory shear flow

    SciTech Connect (OSTI)

    Giacomin, A. J.; Gilbert, P. H.; Schmalzer, A. M.

    2015-03-19

    In our previous work, we explored the dynamics of a dilute suspension of rigid dumbbells as a model for polymeric liquids in large-amplitude oscillatory shear flow, a flow experiment that has gained a significant following in recent years. We chose rigid dumbbells since these are the simplest molecular model to give higher harmonics in the components of the stress response. We derived the expression for the dumbbell orientation distribution, and then we used this function to calculate the shear stress response, and normal stress difference responses in large-amplitude oscillatory shear flow. In this paper, we deepen our understanding of the polymer motion underlying large-amplitude oscillatory shear flow by decomposing the orientation distribution function into its first five Fourier components (the zeroth, first, second, third, and fourth harmonics). We use three-dimensional images to explore each harmonic of the polymer motion. Our analysis includes the three most important cases: (i) nonlinear steady shear flow (where the Deborah number λω is zero and the Weissenberg number λγ 0 is above unity), (ii) nonlinear viscoelasticity (where both λω and λγ 0 exceed unity), and (iii) linear viscoelasticity (where λω exceeds unity and where λγ 0 approaches zero). We learn that the polymer orientation distribution is spherical in the linear viscoelastic regime, and otherwise tilted and peanut-shaped. We find that the peanut-shaping is mainly caused by the zeroth harmonic, and the tilting, by the second. The first, third, and fourth harmonics of the orientation distribution make only slight contributions to the overall polymer motion.

  11. Markov chain decomposition of monthly rainfall into daily rainfall: Evaluation of climate change impact

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

    Yoo, Chulsang; Lee, Jinwook; Ro, Yonghun

    2016-01-01

    This paper evaluates the effect of climate change on daily rainfall, especially on the mean number of wet days and the mean rainfall intensity. Assuming that the mechanism of daily rainfall occurrences follows the first-order Markov chain model, the possible changes in the transition probabilities are estimated by considering the climate change scenarios. Also, the change of the stationary probabilities of wet and dry day occurrences and finally the change in the number of wet days are derived for the comparison of current (1x CO2) and 2x CO2conditions. As a result of this study, the increase or decrease in themore » mean number of wet days was found to be not enough to explain all of the change in monthly rainfall amounts, so rainfall intensity should also be modified. The application to the Seoul weather station in Korea shows that about 30% of the total change in monthly rainfall amount can be explained by the change in the number of wet days and the remaining 70% by the change in the rainfall intensity. That is, as an effect of climate change, the increase in the rainfall intensity could be more significant than the increase in the wet days and, thus, the risk of flood will be much highly increased.« less

  12. Fourier decomposition of polymer orientation in large-amplitude oscillatory shear flow

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

    Giacomin, A. J.; Gilbert, P. H.; Schmalzer, A. M.

    2015-03-19

    In our previous work, we explored the dynamics of a dilute suspension of rigid dumbbells as a model for polymeric liquids in large-amplitude oscillatory shear flow, a flow experiment that has gained a significant following in recent years. We chose rigid dumbbells since these are the simplest molecular model to give higher harmonics in the components of the stress response. We derived the expression for the dumbbell orientation distribution, and then we used this function to calculate the shear stress response, and normal stress difference responses in large-amplitude oscillatory shear flow. In this paper, we deepen our understanding of themore » polymer motion underlying large-amplitude oscillatory shear flow by decomposing the orientation distribution function into its first five Fourier components (the zeroth, first, second, third, and fourth harmonics). We use three-dimensional images to explore each harmonic of the polymer motion. Our analysis includes the three most important cases: (i) nonlinear steady shear flow (where the Deborah number λω is zero and the Weissenberg number λγ 0 is above unity), (ii) nonlinear viscoelasticity (where both λω and λγ 0 exceed unity), and (iii) linear viscoelasticity (where λω exceeds unity and where λγ 0 approaches zero). We learn that the polymer orientation distribution is spherical in the linear viscoelastic regime, and otherwise tilted and peanut-shaped. We find that the peanut-shaping is mainly caused by the zeroth harmonic, and the tilting, by the second. The first, third, and fourth harmonics of the orientation distribution make only slight contributions to the overall polymer motion.« less

  13. Novel Composite Hydrogen-Permeable Membranes for Nonthermal Plasma Reactors for the Decomposition of Hydrogen Sulfide

    SciTech Connect (OSTI)

    Morris Argyle; John Ackerman; Suresh Muknahallipatna; Jerry Hamann; Stanislaw Legowski; Gui-Bing Zhao; Sanil John; Ji-Jun Zhang; Linna Wang

    2007-09-30

    The goal of this experimental project was to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a nonthermal plasma and to recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), but it was not achieved at the moderate pressure conditions used in this study. However, H{sub 2}S was successfully decomposed at energy efficiencies higher than any other reports for the high H{sub 2}S concentration and moderate pressures (corresponding to high reactor throughputs) used in this study.

  14. Corrosion-resistant coating prepared by the thermal decomposition of lithium permanganate

    SciTech Connect (OSTI)

    Ferrando, W.A.

    1999-09-01

    A ceramic, metal, or metal alloy surface is covered with lithium permanganate which is then thermally decomposed to produce a corrosion resistant coating on the surface. This coating serves as a primer coating which is preferably covered with an overcoat of a sealing paint.

  15. Method for production of ceramic oxide and carbide bodies by polymer inclusion and decomposition

    DOE Patents [OSTI]

    Quinby, Thomas C.

    1985-01-01

    A method for the preparation of thin, free-standing metal oxide films which are useful as nuclear accelerator target materials. Cations of any metal except those of Group IA and precious metals, such as, U, Zr, Nd, Ce, Th, pr or Cr, are absorbed on a thin film of polymeric material, such as, carboxymethylcellulose, viscose rayon or cellophane. The cation impregnated polymeric material is dried. Then the impregnated film is heated in an inert atmosphere to form a carbonized membrane. The carbonized membrane is oxidized to yield a thin, self-supporting, metal oxide membrane. Or, the membrane can be heated in an inert atmosphere to yield a thin, self-supporting, metal carbide-containing membrane.

  16. Synthesis of phase-pure U2N3 microspheres and its decomposition into UN

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

    Silva, Chinthaka M.; Hunt, Rodney Dale; Snead, Lance Lewis; Terrani, Kurt A.

    2014-12-12

    Uranium mononitride (UN) is important as a nuclear fuel. Fabrication of UN in its microspherical form also has its own merits since the advent of the concept of accident-tolerant fuel, where UN is being considered as a potential fuel in the form of TRISO particles. But, not many processes have been well established to synthesize kernels of UN. Therefore, a process for synthesis of microspherical UN with a minimum amount of carbon is discussed herein. First, a series of single-phased microspheres of uranium sesquinitride (U2N3) were synthesized by nitridation of UO2+C microspheres at a few different temperatures. Resulting microspheres weremore » of low-density U2N3 and decomposed into low-density UN. The variation of density of the synthesized sesquinitrides as a function of its chemical composition indicated the presence of extra (interstitial) nitrogen atoms corresponding to its hyperstoichiometry, which is normally indicated as α-U2N3. Average grain sizes of both U2N3 and UN varied in a range of 1–2.5 μm. In addition, these had a considerably large amount of pore spacing, indicating the potential sinterability of UN toward its use as a nuclear fuel.« less

  17. Effect of exposure environment on surface decomposition of SiC-silver ion implantation diffusion couples

    SciTech Connect (OSTI)

    Gerczak, Tyler J.; Zheng, Guiqui; Field, Kevin G.; Allen, Todd R.

    2014-10-05

    SiC is a promising material for nuclear applications and is a critical component in the construction of tristructural isotropic (TRISO) fuel. A primary issue with TRISO fuel operation is the observed release of 110m Ag from intact fuel particles. The release of Ag has prompted research efforts to directly measure the transport mechanism of Ag in bulk SiC. Recent research efforts have focused primarily on Ag ion implantation designs. The effect of the thermal exposure system on the ion implantation surface has been investigated. Results indicate the utilization of a mated sample geometry and the establishment of a static thermal exposure environment is critical to maintaining an intact surface for diffusion analysis. In conclusion, the nature of the implantation surface and its potential role in Ag diffusion analysis are discussed.

  18. Effect of exposure environment on surface decomposition of SiC-silver ion implantation diffusion couples

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

    Gerczak, Tyler J.; Zheng, Guiqui; Field, Kevin G.; Allen, Todd R.

    2014-10-05

    SiC is a promising material for nuclear applications and is a critical component in the construction of tristructural isotropic (TRISO) fuel. A primary issue with TRISO fuel operation is the observed release of 110m Ag from intact fuel particles. The release of Ag has prompted research efforts to directly measure the transport mechanism of Ag in bulk SiC. Recent research efforts have focused primarily on Ag ion implantation designs. The effect of the thermal exposure system on the ion implantation surface has been investigated. Results indicate the utilization of a mated sample geometry and the establishment of a static thermalmore » exposure environment is critical to maintaining an intact surface for diffusion analysis. In conclusion, the nature of the implantation surface and its potential role in Ag diffusion analysis are discussed.« less

  19. Markov chain decomposition of monthly rainfall into daily rainfall: Evaluation of climate change impact

    SciTech Connect (OSTI)

    Yoo, Chulsang; Lee, Jinwook; Ro, Yonghun

    2016-01-01

    This paper evaluates the effect of climate change on daily rainfall, especially on the mean number of wet days and the mean rainfall intensity. Assuming that the mechanism of daily rainfall occurrences follows the first-order Markov chain model, the possible changes in the transition probabilities are estimated by considering the climate change scenarios. Also, the change of the stationary probabilities of wet and dry day occurrences and finally the change in the number of wet days are derived for the comparison of current (1x CO2) and 2x CO2conditions. As a result of this study, the increase or decrease in the mean number of wet days was found to be not enough to explain all of the change in monthly rainfall amounts, so rainfall intensity should also be modified. The application to the Seoul weather station in Korea shows that about 30% of the total change in monthly rainfall amount can be explained by the change in the number of wet days and the remaining 70% by the change in the rainfall intensity. That is, as an effect of climate change, the increase in the rainfall intensity could be more significant than the increase in the wet days and, thus, the risk of flood will be much highly increased.

  20. Crossed Molecular Beam Studies and Dynamics of Decomposition of Chemically Activated Radicals

    DOE R&D Accomplishments [OSTI]

    Lee, Y. T.

    1973-09-01

    The power of the crossed molecular beams method in the investigation of the dynamics of chemical reactions lies mainly in the direct observation of the consequences of single collisions of well controlled reactant molecules. The primary experimental observations which provide information on reaction dynamics are the measurements of angular and velocity distributions of reaction products.

  1. Decomposition of PCBs in Oils Using Gamma Radiolysis A Treatability Study - Final Report

    SciTech Connect (OSTI)

    B. J. Mincher; R. E. Arbon

    1996-08-01

    Several legacy hydraulic oil waste streams contaminated with Aroclor 1260 and small amounts of Cesium-137 have been in storage at the Idaho National Engineering Laboratory (INEL) due to the lack of appropriate treatment facilities. The goal of this study was to demonstrate that polychlorinated biphenyls (PCBs) could be selectively decomposed in the oils. Removal of the PCB component to less than the 2 mg/L treatment standard should result in a waste oil that is not regulated by the Toxic Substances Control Act. Irradiation of the oils with high gamma-ray doses produces free electrons in the solution that react with PCBs. The reaction results in dechlorination of the PCBs to produce biphenyl. The gamma-ray source was spent reactor fuel stored in the Advanced Test Reactor canal at the INEL. A dry tube extends into the canal which allowed for positioning of samples in the proximity of the fuel. The gamma-ray dose rates at the samples varied from 10 to 30 kGy/h. This was measured using commercially available FWT-60 dosimeters. Irradiation of samples in a series of progressively increasing absorbed doses allowed the generation of rate constants used to predict absorbed doses necessary to meet the 2 mg/kg treatment standard. Three separate irradiation experiments were performed. The first irradiation used a maximum absorbed dose of 183 kGy. This experiment demonstrated that the PCB concentration decreased and allowed calculation of preliminary rate constants. The second irradiation used a maximum absorbed dose of 760 kGy. From this experiment, accurate rate constants were calculated, and the necessary absorbed dose to achieve the treatment standard was calculated. In the third irradiation of 2,242 kGy, all three waste streams were adequately decontaminated.

  2. On the formation and decomposition of C{sub 7}H{sub 8}.

    SciTech Connect (OSTI)

    Klippenstein, S. J.; Harding, L. B.; Georgievskii, Y.; Chemistry; SNL

    2007-01-01

    The kinetics of reactions on the C{sub 7}H{sub 8} surface were studied with state-of-the-art ab initio transition state theory (TST) and master equation methodologies. A priori predictions of the capture rate for C{sub 6}H{sub 5} + CH{sub 3} and for C{sub 7}H{sub 7} + H are obtained from direct variable reaction coordinate TST simulations. These simulations employ small basis set CASPT2 interaction energies coupled with one-dimensional reaction path corrections based on higher level simulations for related reactions. For the C{sub 7}H{sub 7} + H reaction, predictions are obtained for both the total rate and for the branching between toluene, o-isotoluene and p-isotoluene. A mapping of the low energy pathways for isomerization from these three C{sub 7}H{sub 8} isomers identifies a number of processes with barriers at or below the dissociation threshold. Nevertheless, at combustion temperatures the dissociation rates are predicted to exceed the isomerization rates, and it is reasonable to treat the kinetics of each isomer as a simple single well association/dissociation equilibrium. Master equation simulations yield predictions for the temperature and pressure dependence of each of the recombination and dissociation processes, as well as for the C{sub 7}H{sub 7} + H {yields} C{sub 6}H{sub 5} + CH{sub 3} bimolecular reaction. These simulations implement collisional energy transfer probabilities based on the work of Luther and co-workers. The theoretical predictions are found to be in satisfactory agreement with the available experimental data for the photodissociation of toluene, the temperature and pressure dependent dissociation of toluene, and the reaction of benzyl radical with H. For the C{sub 6}H{sub 5} + CH{sub 3} recombination, the theoretical predictions exceed the experimental measurements of Lin and coworkers by a factor of 2 or more for all temperatures.

  3. Metatranscriptomic analysis of lignocellulolytic microbial communities involved in high-solids decomposition of rice straw

    SciTech Connect (OSTI)

    Simmons, Christopher W.; Reddy, Amitha P.; D’haeseleer, Patrik; Khudyakov, Jane; Billis, Konstantinos; Pati, Amrita; Simmons, Blake A.; Singer, Steven W.; Thelen, Michael P.; VanderGheynst, Jean S.

    2014-12-31

    New lignocellulolytic enzymes are needed that maintain optimal activity under the harsh conditions present during industrial enzymatic deconstruction of biomass, including high temperatures, the absence of free water, and the presence of inhibitors from the biomass. Enriching lignocellulolytic microbial communities under these conditions provides a source of microorganisms that may yield robust lignocellulolytic enzymes tolerant to the extreme conditions needed to improve the throughput and efficiency of biomass enzymatic deconstruction. Identification of promising enzymes from these systems is challenging due to complex substrate-enzyme interactions and requirements to assay for activity. In this study, metatranscriptomes from compost-derived microbial communities enriched on rice straw under thermophilic and mesophilic conditions were sequenced and analyzed to identify lignocellulolytic enzymes overexpressed under thermophilic conditions. To determine differential gene expression across mesophilic and thermophilic treatments, a method was developed which pooled gene expression by functional category, as indicated by Pfam annotations, since microbial communities performing similar tasks are likely to have overlapping functions even if they share no specific genes. Differential expression analysis identified enzymes from glycoside hydrolase family 48, carbohydrate binding module family 2, and carbohydrate binding module family 33 domains as significantly overexpressed in the thermophilic community. Overexpression of these protein families in the thermophilic community resulted from expression of a small number of genes not currently represented in any protein database. Genes in overexpressed protein families were predominantly expressed by a single Actinobacteria genus, Micromonospora. In conclusion, coupling measurements of deconstructive activity with comparative analyses to identify overexpressed enzymes in lignocellulolytic communities provides a targeted approach for discovery of candidate enzymes for more efficient biomass deconstruction. Furthermore, glycoside hydrolase family 48 cellulases and carbohydrate binding module family 33 polysaccharide monooxygenases with carbohydrate binding module family 2 domains may improve saccharification of lignocellulosic biomass under high-temperature and low moisture conditions relevant to industrial biofuel production.

  4. Fitting FFT-derived spectra: Theory, tool, and application to solar radio spike decomposition

    SciTech Connect (OSTI)

    Nita, Gelu M.; Fleishman, Gregory D.; Gary, Dale E.; Marin, William; Boone, Kristine

    2014-07-10

    Spectra derived from fast Fourier transform (FFT) analysis of time-domain data intrinsically contain statistical fluctuations whose distribution depends on the number of accumulated spectra contributing to a measurement. The tail of this distribution, which is essential for separating the true signal from the statistical fluctuations, deviates noticeably from the normal distribution for a finite number of accumulations. In this paper, we develop a theory to properly account for the statistical fluctuations when fitting a model to a given accumulated spectrum. The method is implemented in software for the purpose of automatically fitting a large body of such FFT-derived spectra. We apply this tool to analyze a portion of a dense cluster of spikes recorded by our FASR Subsystem Testbed instrument during a record-breaking event that occurred on 2006 December 6. The outcome of this analysis is briefly discussed.

  5. Proper Orthogonal Decomposition of the Flow in a T-Junction (In: Advances

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

    Study - Propane Bakery Delivery Step Vans April 2016 1 Contents Background .......................................................................................................................................................................... 3 Motivation for Adopting Propane ................................................................................................................................... 3 Financial Benefits

  6. Method for production of ceramic oxide and carbide bodies by polymer inclusion and decomposition

    DOE Patents [OSTI]

    Quinby, T.C.

    1984-08-30

    A method for the preparation of thin, free-standing metal oxide films which are useful as nuclear accelerator target materials is described. Cations of any metal except those of Group IA and precious metals, such as, U, Zr, Nd, Ce, Th, Pr or Cr, are absorbed on a thin film of polymeric material, such as carboxymethylcellulose, viscose rayon or cellophane. The cation impregnated polymeric material is dried. Then the impregnated film is heated in an inert atmosphere to form a carbonized membrane. The carbonized membrane is oxidized to yield a thin, self-supporting, metal oxide membrane. Or, the membrane can be heated in an inert atmosphere to yield a thin, self-supporting, metal carbide-containing membrane.

  7. Isospin Decomposition of the Photoproduced Sigma pi System Near the Lambda(1405)

    SciTech Connect (OSTI)

    Carnegie Mellon U.; Indiana U.

    2013-09-01

    Recent experimental results for the reaction \\gamma + p \\to K^+ + \\Sigma + \\pi\\ from CLAS at Jefferson Lab are discussed. It was found that the mass distributions or "line shapes" of the three charge combinations \\Sigma^+ \\pi^-, \\Sigma^0 \\pi^0 and \\Sigma^- \\pi^+ differ significantly. Our results show that the \\Lambda(1405), as the I=0 constituent of the reaction, must be accompanied by an I > 0 component. We discuss phenomenological fits to the data to test the possible forms and magnitudes of these amplitudes. A two-amplitude I=0 fit of Breit-Wigner form to the \\Sigma^0\\pi^0 channel alone works quite well. The addition of a single I=1 amplitude works fairly well to model all the line shapes simultaneously.

  8. Hydrogen production from water decomposition by redox of Fe{sub...

    Office of Scientific and Technical Information (OSTI)

    DOI: 10.1016j.jssc.2010.03.017; PII: S0022-4596(10)00095-2; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved. Country of...

  9. Douglas Jacobsen! NERSC Bioinformatics Computing Consultant

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

    * By d efault, q stat o nly s hows y our j obs * To s ee o thers, q stat --- u < username> o r q stat --- u * * State: - r: " running" - qw: " queue---wait" - R: " ...

  10. BPA-2014-01328-FOIA Response

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

    0 Alarm 181 Auto Accident 0 Client Comp. 0 Emergency 0 Fire 0 Open SafeFile 0 Prop. Damage 0 Safety Hazard 0 Susp Person(s) 0 Theft 0 Water Leak 00ther Explain: Vehicle...

  11. A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback

    SciTech Connect (OSTI)

    Koven, C. D.; Schuur, E. A. G.; Schadel, C.; Bohn, T. J.; Burke, E. J.; Chen, G.; Chen, X.; Ciais, P.; Grosse, G.; Harden, J. W.; Hayes, D. J.; Hugelius, G.; Jafarov, E. E.; Krinner, G.; Kuhry, P.; Lawrence, D. M.; MacDougall, A. H.; Marchenko, S. S.; McGuire, A. D.; Natali, S. M.; Nicolsky, D. J.; Olefeldt, D.; Peng, S.; Romanovsky, V. E.; Schaefer, K. M.; Strauss, J.; Treat, C. C.; Turetsky, M.

    2015-10-05

    We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation–Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2–33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9–112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change (γ sensitivity) of –14 to –19 Pg C °C–1 on a 100 year time scale. For CH4 emissions, our approach assumes a fixed saturated area and that increases in CH4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10–18

  12. A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback

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

    Koven, C. D.; Schuur, E. A. G.; Schadel, C.; Bohn, T. J.; Burke, E. J.; Chen, G.; Chen, X.; Ciais, P.; Grosse, G.; Harden, J. W.; et al

    2015-10-05

    We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation–Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soilmore » temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2–33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9–112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change (γ sensitivity) of –14 to –19 Pg C °C–1 on a 100 year time scale. For CH4 emissions, our approach assumes a fixed saturated area and that increases in CH4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10–18%. In conclusion, the

  13. Measurements of the Neutron Longitudinal Spin Asymmetry A1n and Flavor Decomposition in the Valence Quark Region

    SciTech Connect (OSTI)

    Flay, David J.

    2014-08-01

    The current data for the nucleon-virtual photon longitudinal spin asymmetry A1 on the proton and neutron have shown that the ratio of the polarized-to-unpolarized down-quarkparton distribution functions,Dd=d, tends towards -1/2 at large x, in disagreement with the perturbative QCD prediction that Dd/d approaches 1 but more in line with constituent quark models. As a part of experiment E06-014 in Hall A of Jefferson Lab, double-spin asymmetries were measured in the scattering of a longitudinally polarized electron beam of energies 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target in the deep inelastic scattering and resonance region, allowing for the extraction of the neutron asymmetry An1 and the ratios Dd/d and Du/u. We will discuss our analysis of the data and present results for A1 and g1/F1 on both 3He and the neutron, and the resulting quark ratios for the up and down quarks in the kinematic range of 0.2

  14. Mesoporous carbon-containing MoS{sub 2} materials formed from the in situ decomposition of tetraalkylammonium thiomolybdates

    SciTech Connect (OSTI)

    Alonso, Gabriel; Berhault, Gilles; Paraguay, Francisco; Rivera, Eric; Fuentes, Sergio; Chianelli, Russell R

    2003-05-26

    Molybdenum disulfide with unique mesoporous structure was synthesized from tetraalkylammonium thiometallate precursors in situ decomposed in a batch reactor in the presence of dibenzothiophene (DBT). The precursors used in this study were tetraalkylammonium thiomolybdates with alkyl groups ranging from propyl to octyl. Molybdenum disulfide thus prepared presents high surface area (from 255 up to 329 m{sup 2}/g), high content of carbon (C/Mo=2.7-4.0) and type IV nitrogen adsorption-desorption isotherms when decomposed from tetrahexyl-, tetraheptyl- or tetraoctylammonium thiomolybdates. The as-formed materials are poorly crystallized with a very weak intensity of the (0 0 2) peak of the 2H-MoS{sub 2} structure. Such diffraction patterns are characteristic of exfoliated samples. Characterization by TEM shows a disordered layered structure with no long range order for the MoS{sub 2} catalysts. Therefore, the nature of the alkyl group in the precursor affects both the surface area and the pore size distribution of the final MoS{sub 2} catalysts with a progressive morphological modification up to a mesoporous organization.

  15. Silver-Mordenite for Radiologic Gas Capture from Complex Streams: Dual Catalytic CH3I Decomposition and I Confinement

    SciTech Connect (OSTI)

    Tina M. Nenoff; Mark Rodriguez; Nick Soelberg; Karena W. Chapman

    2014-12-01

    The effective capture and storage of radiological iodine (129I) remains a strong concern for safe nuclear waste storage and safe nuclear energy. Silver-containing mordenite (MOR) is a longstanding benchmark for iodine capture. In nuclear fuel reprocessing scenarios, complex gas streams will be present and the need for high selectivity of all iodine containing compounds is of the utmost importance for safety and the environment. In particular, a molecular level understanding of the sorption of organic iodine compounds is not well understood. Here we probe the structure and distribution of methyl iodide sorbed by silver-containing MOR using a combination of crystallographic and materials characterization techniques including: infrared spectroscopy, thermogravimetric analysis with mass spectrometry, Micro-X-ray Fluorescence, powder X-ray diffraction analysis, and pair distribution function analysis. The iodine is captured inside the MOR pore in the form of AgI nanoparticles, that is consistent with the pores sizes of the MOR, indicating that the molecule is both physically and chemically captured in the Ag-MOR. The organic component is surface catalyzed by the zeolite via the formation of Surface Methoxy Species (SMS) that result in downstream organics of dimethyl ether and methanol formation.

  16. Decomposition of tetraphenylborate precipitates used to isolate Cs-137 from Savannah River Site high-level waste

    SciTech Connect (OSTI)

    Ferrara, D.M.; Bibler, N.E.; Ha, B.C.

    1993-03-01

    This paper presents results of the radioactive demonstration of the Precipitate Hydrolysis Process (PHP) that will be performed in the Defense Waste Processing Facility (DWPF) at the Savannah River Site. The PHP destroys the tetraphenylborate precipitate that is used at SRS to isolate Cs-137 from caustic High-Level Waste (HLW) supernates. This process is necessary to decrease the amount of organic compounds going to the melter in the DWPF. Actual radioactive precipitate containing Cs-137 was used for this demonstration.

  17. NOVEL COMPOSITE HYDROGEN-PERMEABLE MEMBRANES FOR NON-THERMAL PLASMA REACTORS FOR THE DECOMPOSITION OF HYDROGEN SULFIDE

    SciTech Connect (OSTI)

    Morris D. Argyle; John F. Ackerman; Suresh Muknahallipatna; Jerry C. Hamann; Stanislaw Legowski; Ji-Jun Zhang; Guibing Zhao; Robyn J. Alcanzare; Linna Wang; Ovid A. Plumb

    2004-07-01

    The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a non-thermal plasma and recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. Experiments involving methane conversion reactions were conducted with a preliminary pulsed corona discharge reactor design in order to test and improve the reactor and membrane designs using a non-toxic reactant. This report details the direct methane conversion experiments to produce hydrogen, acetylene, and higher hydrocarbons utilizing a co-axial cylinder (CAC) corona discharge reactor, pulsed with a thyratron switch. The reactor was designed to accommodate relatively high flow rates (655 x 10{sup -6} m{sup 3}/s) representing a pilot scale easily converted to commercial scale. Parameters expected to influence methane conversion including pulse frequency, charge voltage, capacitance, residence time, and electrode material were investigated. Conversion, selectivity and energy consumption were measured or estimated. C{sub 2} and C{sub 3} hydrocarbon products were analyzed with a residual gas analyzer (RGA). In order to obtain quantitative results, the complex sample spectra were de-convoluted via a linear least squares method. Methane conversion as high as 51% was achieved. The products are typically 50%-60% acetylene, 20% propane, 10% ethane and ethylene, and 5% propylene. First Law thermodynamic energy efficiencies for the system (electrical and reactor) were estimated to range from 38% to 6%, with the highest efficiencies occurring at short residence time and low power input (low specific energy) where conversion is the lowest (less than 5%). The highest methane conversion of 51% occurred at a residence time of 18.8 s with a flow rate of 39.4 x 10{sup -6} m{sup 3}/s (5 ft{sup 3}/h) and a specific energy of 13,000 J/l using niobium and platinum coated stainless steel tubes as cathodes. Under these conditions, the First Law efficiency for the system was 8%. Under similar reaction conditions, methane conversions were {approx}50% higher with niobium and platinum coated stainless steel cathodes than with a stainless steel cathode.

  18. Investigating the Mechanism of Catalytic Tetraphenylborate Decomposition Using Nuclear Magnetic Resonance Spectrometry: Initial Studies in FY00

    SciTech Connect (OSTI)

    Bonnesen, P.V.

    2001-01-30

    The key findings from this study can be summarized as follows: (1) palladium appears to be capable of catalyzing the degradation in the absence of mercury; (2) when mercury was added to the palladium system in the form of mercuric nitrate or phenylmercuric nitrate basic, the rate of TPB degradation was roughly the same as the rate without mercury present; (3) when mercury was added to the system in the form of diphenylmercury, the rate of TPB degradation was greatly accelerated; (4) no TPB degradation was observed for a system which contained phenylmercuric nitrate basic alone with no palladium present; (5) the distribution of lower phenylborates (1 PB, 2PB, and 3PB) varied as a function of the catalyst system; (6) no lower phenylborates were observed during the first 17 hours of reaction indicating that an ''induction period'' may be necessary; and (7) the appearance of precipitates in the reaction mixture varied with the catalyst system, possibly indicating that the active catalyst that is formed may vary with the chemical form of mercury added.

  19. The Investigation of Decomposition of Supersaturated Si Solid Solution by X-Ray Diffuse Scattering

    SciTech Connect (OSTI)

    Shcherbachev, Kirill; Privezentsev, Vladimir

    2010-04-06

    The results of investigation of microstructure of Zn doped n-type Si by X-ray Diffuse Scattering (XRDS) are presented. Experimental samples were made by a high-temperature Zn diffusion annealing with subsequent quenching and tempering. Reciprocal space maps of XRDS were obtained. They resulted in that crystal lattice of the samples contains spherical MDs of vacancy type and plane shape MDs of interstitial type. The MDs average radius and their type depend on Zn doping level and thermal treatment after Zn diffusion.

  20. Effects of organic matter and its anaerobic decomposition products on the growth and zinc uptake by Oryza sativa

    SciTech Connect (OSTI)

    Kang, Y.

    1987-01-01

    In this study, the effect of organic acid and bicarbonate on plant growth and Zn uptake, effects of organic matter addition on various Zn fractions at different pH levels were investigated. Organic acids, acetic, propionic and butyric acids at 5 meq/l, caused reduced plant growth and impaired Zn uptake. Plant toxicity by organic acids was greatest at low pH which was related to the increased concentration of undissociated acid concentration in the nutrient media. The relative injury severity of organic acids to plant growth was in the order of butyric > propionic > acetic acid. Bicarbonate ion concentration, greater than 5 meq/l significantly decreased Zn uptake by rice shoots and roots. The combined effect of high pH and high bicarbonate ion concentration had the greatest detrimental effect on rice seedling growth and Zn uptake. In a Zn fraction experiment, seven Zn pools were separated. Multiple regression and path-coefficient analysis indicated that water soluble + exchangeable Zn, Zn weakly complexed to OM, and Zn bound to OM are the major contributors to plant Zn uptake.

  1. Scott French! NERSC User Services Group! New User Training!

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

    French! NERSC User Services Group! ! New User Training! August 13, 2015 Computing Environment Node Types * Login nodes - Shared w ith o ther u sers - Code c ompila3on, j ob p repara3on a nd s ubmission * MOM n odes ( Cray m achines) - Shared w ith o ther u sers - Where b atch s cript e xecutes - Will g o a way w hen w e t ransi3on t o S LURM * Compute n odes - Not s hared ( except s erial q ueues) --- 2 --- Login Node Configuration * Edison - Twelve n odes * 16 c ores, 2 .0 G Hz I ntel S andy B

  2. J U N E

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    J U N E 1 5 , 2 0 1 5 | W A S H I N G T O N , D C Stephen J . R ourke V I C E P R E S I D ... g as, b iomass, o ther b iomass g as, w ind, s olar, m unicipal s olid w aste, a nd ...

  3. NERSC_ASCR_Requirements_Review-1.pptx

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

    15, 2014 LBNL Outline * Goal: i mproved w idely u sed l inear a lgebra (and o ther) l ... t o a Nain n eeded a ccuracy * What H WSW f eatures d o w e n eed t o d o t his? ...

  4. Microsoft Word - 4.11.2013 ANGA QER Written Statement.docx

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

    S o w e a ppreciate t he emphasis o n t his s ubject d uring t he f irst y ear o f t he q ... M ore t han o ther f uels, w e a lso p rovide consistent, f lexible p ower t hat h elps m ...

  5. Method of freezing living cells and tissues with improved subsequent survival

    DOE Patents [OSTI]

    Senkan, Selim M.; Hirsch, Gerald P.

    1980-01-01

    This invention relates to an improved method for freezing red blood cells, ther living cells, or tissues with improved subsequent survival, wherein constant-volume freezing is utilized that results in significantly improved survival compared with constant-pressure freezing; optimization is attainable through the use of different vessel geometries, cooling baths and warming baths, and sample concentrations.

  6. The Los Alamos Postdoc Career Fair is an

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

    m aterials t echnology, s uper---compu>ng, a nd m any other fi elds. L ANL h as a l ong---standing t radi>on o f p artnering with u niversi>es, i ndustries, a nd o ther n...

  7. A coupled transport and solid mechanics formulation with improved reaction kinetics parameters for modeling oxidation and decomposition in a uranium hydride bed.

    SciTech Connect (OSTI)

    Salloum, Maher N.; Shugard, Andrew D.; Kanouff, Michael P.; Gharagozloo, Patricia E.

    2013-03-01

    Modeling of reacting flows in porous media has become particularly important with the increased interest in hydrogen solid-storage beds. An advanced type of storage bed has been proposed that utilizes oxidation of uranium hydride to heat and decompose the hydride, releasing the hydrogen. To reduce the cost and time required to develop these systems experimentally, a valid computational model is required that simulates the reaction of uranium hydride and oxygen gas in a hydrogen storage bed using multiphysics finite element modeling. This SAND report discusses the advancements made in FY12 (since our last SAND report SAND2011-6939) to the model developed as a part of an ASC-P&EM project to address the shortcomings of the previous model. The model considers chemical reactions, heat transport, and mass transport within a hydride bed. Previously, the time-varying permeability and porosity were considered uniform. This led to discrepancies between the simulated results and experimental measurements. In this work, the effects of non-uniform changes in permeability and porosity due to phase and thermal expansion are accounted for. These expansions result in mechanical stresses that lead to bed deformation. To describe this, a simplified solid mechanics model for the local variation of permeability and porosity as a function of the local bed deformation is developed. By using this solid mechanics model, the agreement between our reacting bed model and the experimental data is improved. Additionally, more accurate uranium hydride oxidation kinetics parameters are obtained by fitting the experimental results from a pure uranium hydride oxidation measurement to the ones obtained from the coupled transport-solid mechanics model. Finally, the coupled transport-solid mechanics model governing equations and boundary conditions are summarized and recommendations are made for further development of ARIA and other Sandia codes in order for them to sufficiently implement the model.

  8. Obtaining aluminas from the thermal decomposition of their different precursors: An {sup 27}Al MAS NMR and X-ray powder diffraction studies

    SciTech Connect (OSTI)

    Chagas, L.H.; De Carvalho, G.S.G.; San Gil, R.A.S.; Chiaro, S.S.X.; Leito, A.A.; Diniz, R.

    2014-01-01

    Graphical abstract: - Highlights: We synthesized three precursors of alumina from different methods. The calcination of the precursors generated several alumina polymorphs. XRD and NMR were used for structural investigation of the polymorphs. The synthesis route determines the structural and textural properties of the solids. - Abstract: A commercial sample of Boehmite was used as precursor of alumina polymorphs. For comparison, three other precursors were synthesized from different methods. Particularly, the use of excess of urea promoted a very crystalline form of basic aluminum carbonate. The characteristics of the four precursors were investigated by thermal, vibrational and X-ray powder diffraction (XRD) analysis. Additionally, the nuclear magnetic resonance, with magic angle spinning ({sup 27}Al MAS NMR), was used to verify the coordination of aluminum cations. Each precursor was calcined at various temperatures generating alumina polymorphs, which were structurally analyzed by XRD and {sup 27}Al MAS NMR. Due to interest in catalysis supports, special attention was given to the ?-Al{sub 2}O{sub 3} phase, which in addition to structural investigation was subjected to textural analysis. The results showed that, from different synthesis procedures and common route of calcination, one can obtain materials with the same composition but with different structural and textural properties, which in turn can significantly influence the performance of a supported catalyst.

  9. Analytical gradients of complete active space self-consistent field energies using Cholesky decomposition: Geometry optimization and spin-state energetics of a ruthenium nitrosyl complex

    SciTech Connect (OSTI)

    Delcey, Mickaël G.; Freitag, Leon; González, Leticia; Pedersen, Thomas Bondo; Aquilante, Francesco; Dipartimento di Chimica “G. Ciamician,” Università di Bologna, V. F. Selmi 2, 40126 Bologna ; Lindh, Roland; Uppsala Center for Computational Chemistry - UC3, Uppsala University, Box 518, 751 20 Uppsala

    2014-05-07

    We present a formulation of analytical energy gradients at the complete active space self-consistent field (CASSCF) level of theory employing density fitting (DF) techniques to enable efficient geometry optimizations of large systems. As an example, the ground and lowest triplet state geometries of a ruthenium nitrosyl complex are computed at the DF-CASSCF level of theory and compared with structures obtained from density functional theory (DFT) using the B3LYP, BP86, and M06L functionals. The average deviation of all bond lengths compared to the crystal structure is 0.042 Å at the DF-CASSCF level of theory, which is slightly larger but still comparable with the deviations obtained by the tested DFT functionals, e.g., 0.032 Å with M06L. Specifically, the root-mean-square deviation between the DF-CASSCF and best DFT coordinates, delivered by BP86, is only 0.08 Å for S{sub 0} and 0.11 Å for T{sub 1}, indicating that the geometries are very similar. While keeping the mean energy gradient errors below 0.25%, the DF technique results in a 13-fold speedup compared to the conventional CASSCF geometry optimization algorithm. Additionally, we assess the singlet-triplet energy vertical and adiabatic differences with multiconfigurational second-order perturbation theory (CASPT2) using the DF-CASSCF and DFT optimized geometries. It is found that the vertical CASPT2 energies are relatively similar regardless of the geometry employed whereas the adiabatic singlet-triplet gaps are more sensitive to the chosen triplet geometry.

  10. The effect of PECVD plasma decomposition on the wettability and dielectric constant changes in silicon modified DLC films for potential MEMS and low stiction applications

    SciTech Connect (OSTI)

    Ogwu, A. A.; Okpalugo, T. I. T.; McLaughlin, J. A. D.

    2012-09-15

    We have carried out investigations aimed at understanding the mechanism responsible for a water contact angle increase of up to ten degrees and a decrease in dielectric constant in silicon modified hydrogenated amorphous carbon films compared to unmodified hydrogenated amorphous carbon films. Our investigations based on surface chemical constituent analysis using Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), SIMS, FTIR, contact angle / surface energy measurements and spectroscopic ellipsometry suggests the presence of hydrophobic chemical entities on the surface of the films. This observation is consistent with earlier theoretical plasma chemistry predictions and observed Raman peak shifts in the films. These surface hydrophobic entities also have a lower polarizability than the bonds in the un-modified films thereby reducing the dielectric constant of the silicon modified films measured by spectroscopic ellipsometry. Ellipsometric dielectric constant measurement is directly related to the surface energy through Hamaker's constant. Our current finding is expected to be of benefit to understanding stiction, friction and lubrication in areas that range from nano-tribology to microfluidics.

  11. Photo-initiated reactions of 2,4,6 TCP on Degussa P25 formulation TiO{sub 2} : wavelength sensitive decomposition.

    SciTech Connect (OSTI)

    Hurum, D. C.; Gray, K. A.; Rajh, T.; Thurnauer, M. C.; Chemistry; Northwestern Univ.

    2004-10-21

    The photoinitiated oxidative reactions of 2,4,6 trichlorophenol (2,4,6 TCP) and 2,4,5 trichlorophenol (2,4,5 TCP) are studied on the titania photocatalyst Degussa P25. On this catalyst 2,4,6 TCP is used to confirm two distinct oxidative mechanisms that are triggered at different light-excitation wavelengths. A charge-transfer mechanism occurs at sub-bandgap energies of the photocatalyst leading to a phenoxyl radical product and an oxidative mechanism occurs at the bandgap leading to a semiquinone radical product. The wavelength dependence of these two mechanisms is discussed.

  12. Synthesis of phase-pure U2N3 microspheres and its decomposition into UN

    SciTech Connect (OSTI)

    Silva, Chinthaka M.; Hunt, Rodney Dale; Snead, Lance Lewis; Terrani, Kurt A.

    2014-12-12

    Uranium mononitride (UN) is important as a nuclear fuel. Fabrication of UN in its microspherical form also has its own merits since the advent of the concept of accident-tolerant fuel, where UN is being considered as a potential fuel in the form of TRISO particles. But, not many processes have been well established to synthesize kernels of UN. Therefore, a process for synthesis of microspherical UN with a minimum amount of carbon is discussed herein. First, a series of single-phased microspheres of uranium sesquinitride (U2N3) were synthesized by nitridation of UO2+C microspheres at a few different temperatures. Resulting microspheres were of low-density U2N3 and decomposed into low-density UN. The variation of density of the synthesized sesquinitrides as a function of its chemical composition indicated the presence of extra (interstitial) nitrogen atoms corresponding to its hyperstoichiometry, which is normally indicated as α-U2N3. Average grain sizes of both U2N3 and UN varied in a range of 1–2.5 μm. In addition, these had a considerably large amount of pore spacing, indicating the potential sinterability of UN toward its use as a nuclear fuel.

  13. MgCoAl and NiCoAl LDHs synthesized by the hydrothermal urea hydrolysis method: Structural characterization and thermal decomposition

    SciTech Connect (OSTI)

    Chagas, L.H.; De Carvalho, G.S.G.; Do Carmo, W.R.; San Gil, R.A.S.; Chiaro, S.S.X.; Leitão, A.A.; Diniz, R.; De Sena, L.A.; Achete, C.A.

    2015-04-15

    Highlights: • We synthesized MgCoAl and NiCoAl LDHs by the urea hydrolysis method. • Aluminum rich and crystalline materials have been formed. • The calcination of the LDHs generated mixed oxides with high surface areas. - Abstract: Layered double hydroxides (LDHs) with Mg/Co/Al and Ni/Co/Al were synthesized for the first time by the urea hydrolysis method. The experimental conditions promoted aluminum rich and crystalline materials. The formation of LDHs was investigated by powder X-ray diffraction (XRD), chemical analysis, solid state nuclear magnetic resonance with magic angle spinning ({sup 27}Al-MAS-NMR), simultaneous thermogravimetric/differential thermal analysis (TGA/DTA), FTIR spectroscopy, scanning electron microscopy (SEM), and N{sub 2} adsorption–desorption experiments. A single phase corresponding to LDH could be obtained in all the investigated compositions. Thermal calcination of these LDHs at 500 °C resulted in the formation of solid solutions in which Al{sup 3+} was dissolved. All the calcined materials have rock-salt like structures and high surface areas.

  14. Molybdenum-based additives to mixed-metal oxides for use in hot gas cleanup sorbents for the catalytic decomposition of ammonia in coal gases

    DOE Patents [OSTI]

    Ayala, Raul E.

    1993-01-01

    This invention relates to additives to mixed-metal oxides that act simultaneously as sorbents and catalysts in cleanup systems for hot coal gases. Such additives of this type, generally, act as a sorbent to remove sulfur from the coal gases while substantially simultaneously, catalytically decomposing appreciable amounts of ammonia from the coal gases.

  15. Application of the base catalyzed decomposition process to treatment of PCB-contaminated insulation and other materials associated with US Navy vessels. Final report

    SciTech Connect (OSTI)

    Schmidt, A.J.; Zacher, A.H.; Gano, S.R.

    1996-09-01

    The BCD process was applied to dechlorination of two types of PCB-contaminated materials generated from Navy vessel decommissioning activities at Puget Sound Naval Shipyard: insulation of wool felt impregnated with PCB, and PCB-containing paint chips/debris from removal of paint from metal surfaces. The BCD process is a two-stage, low-temperature chemical dehalogenation process. In Stage 1, the materials are mixed with sodium bicarbonate and heated to 350 C. The volatilized halogenated contaminants (eg, PCBs, dioxins, furans), which are collected in a small volume of particulates and granular activated carbon, are decomposed by the liquid-phase reaction (Stage 2) in a stirred-tank reactor, using a high-boiling-point hydrocarbon oil as the reaction medium, with addition of a hydrogen donor, a base (NaOH), and a catalyst. The tests showed that treating wool felt insulation and paint chip wastes with Stage 2 on a large scale is feasible, but compared with current disposal costs for PCB-contaminated materials, using Stage 2 would not be economical at this time. For paint chips generated from shot/sand blasting, the solid-phase BCD process (Stage 1) should be considered, if paint removal activities are accelerated in the future.

  16. Interplay of topological surface and bulk electronic states in...

    Office of Scientific and Technical Information (OSTI)

    Title: Interplay of topological surface and bulk electronic states in Bi2Se3 Authors: Romanowich, Megan ; Lee, Mal-Soon ; Chung, Duck-Young ; Mahanti, S. D. ; Kanatzidis, Mercouri ...

  17. l[nterial &oratory the New York h'

    Office of Legacy Management (LM)

    re- ceive and possess 25 gram3 of umnium (20 percent enrichment in uwnium 235) in the form of uranyl nitrate, for radiation chemistry osperiments. MalZnckrodt Chanical1Vork.q St. ...

  18. MSWGW

    Office of Legacy Management (LM)

    ... ground water following remediation of the millsite, 4) to evaluate health risks to humans, plants and ani- mals, and 5) to evaluate remediation options for soil and ground water. ...

  19. AFV CoverSheet

    Office of Scientific and Technical Information (OSTI)

    ... In our search for new families of heavy fermion compounds that may show interesting behavior, we focus our attention on CeMAl4Si2 (MRh, Ir, Pt). These compounds adopt a tetragonal ...

  20. MODEL REDUCTION WITH MAPREDUCE-ENABLED TALL AND SKINNY SINGULAR...

    Office of Scientific and Technical Information (OSTI)

    AND SKINNY SINGULAR VALUE DECOMPOSITION. Citation Details In-Document Search Title: MODEL REDUCTION WITH MAPREDUCE-ENABLED TALL AND SKINNY SINGULAR VALUE DECOMPOSITION. Abstract ...

  1. Do financial investors destabilize the oil price?

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    ... Moreover, we test whether the ine cient ...nancial trading shock (iii) increased the ... To test for this, we generate the variance decomposition and the historical decomposition ...

  2. Water-splitting using photocatalytic porphyrin-nanotube composite devices

    DOE Patents [OSTI]

    Shelnutt, John A.; Miller, James E.; Wang, Zhongchun; Medforth, Craig J.

    2008-03-04

    A method for generating hydrogen by photocatalytic decomposition of water using porphyrin nanotube composites. In some embodiments, both hydrogen and oxygen are generated by photocatalytic decomposition of water.

  3. Section 15

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

    An Internal Analysis of SGP/CART Radiosonde Performance During the September 1996 Water Vapor Intensive Observation Period B. M. Lesht Argonne National Laboratory Argonne, Illinois Introduction The September 1996 Water Vapor Intensive Observation Per- iod (IOP) provided an excellent opportunity to investigate fur- ther the operational performance of the radiosondes used by ARM at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site. Although many instrument inter- comparisons

  4. Growth and characterization of thin oriented Co{sub 3}O{sub 4} (111) films obtained by decomposition of layered cobaltates Na{sub x}CoO{sub 2}

    SciTech Connect (OSTI)

    Buršík, Josef; Soroka, Miroslav; Kužel, Radomír; Mika, Filip

    2015-07-15

    The formation and structural characterization of highly (111)-oriented Co{sub 3}O{sub 4} films prepared by a novel procedure from weakly (001)-oriented Na{sub x}CoO{sub 2} is reported. The Na{sub x}CoO{sub 2} films were deposited on both single crystal and amorphous substrates by chemical solution deposition (CSD) method and crystallized at 700 °C. Subsequently they were transformed into (111)-oriented Co{sub 3}O{sub 4} phase during post-growth annealing at 900 °C. The degree of preferred orientation in Co{sub 3}O{sub 4}, which was determined by phi-scan and pole figure measurements, depends on the content of Na in the starting Na{sub x}CoO{sub 2} phase. Surface morphology of the films was investigated using electron microscopy and atomic force microscopy. - Graphical abstract: Structure of growth twins and possible O{sup 2−} stacking sequences in (111)-oriented Co{sub 3}O{sub 4} thin films on α-Al{sub 2}O{sub 3}(001) prepared by chemical solution deposition through the transformation of (001)-oriented Na{sub x}CoO{sub 2} thin film. - Highlights: • Single phase Co{sub 3}O{sub 4} thin films was prepared by means of chemical solution deposition. • Conditions for γ-Na{sub x}CoO{sub 2} to Co{sub 3}O{sub 4} transformation were optimized. • Growth twinning of Co{sub 3}O{sub 4} films due to two possible O{sup 2−} stacking sequences. • Growth with (pseudo)epitaxial relation Co{sub 3}O{sub 4} (111)[−121]//α-Al{sub 2}O{sub 3} (001)[10−10].

  5. WEC-Sim-METS2014_Final

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

    radiation added---mass and damping terms from other bodies, whereas Babarit [14] 7 considers these terms. Further studies are underway to develop the capability to model off--- diagonal h ydrodynamic f orces f rom o ther b odies. CONCLUSIONS NREL and SNL have developed an open---source numerical m odeling t ool f or d esign a nd a nalysis o f a wide span of WEC devices. In this paper, we applied WEC---Sim to model a two---body floating--- point absorber and two types of oscillating surge

  6. Ankit Bhagatwala! NERSC User Services Group! New User Training!

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

    Ankit Bhagatwala! NERSC User Services Group! ! New User Training! March 21, 2016 Computing Environment Node Types * Login nodes - Shared w ith o ther u sers - Code c ompila3on, j ob p repara3on a nd s ubmission * Compute n odes - Not s hared ( except s hared q ueue o n C ori) * Service nodes - File s ystem a ccess ( lustre), d ata m ovement ( HPSS), network c onnec3ons t o o utside w orld, e tc. - Not a ccessed d irectly --- 2 --- Login Node Configuration * Edison - Twelve n odes * 16 c ores, 2

  7. Conceptual Design for a High-Temperature Gas Loop Test Facility

    SciTech Connect (OSTI)

    James B. Kesseli

    2006-08-01

    This report documents an early-stage conceptual design for a high-temperature gas test loop. The objectives accomplished by the study include, (1) investigation of existing gas test loops to determine ther capabilities and how the proposed system might best complement them, (2) development of a preliminary test plan to help identify the performance characteristics required of the test unit, (3) development of test loop requirements, (4) development of a conceptual design including process flow sheet, mechanical layout, and equipment specifications and costs, and (5) development of a preliminary test loop safety plan.

  8. SkinnerMatgetFinal.pptx

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

    aterials G enomics Kris0n P ersson, A nubhav J ain, D an G unter ( LBNL), G erbrand Ceder ( MIT), G eoffroy H au0er ( UCL) M ark A sta ( UCB), A lan Dozier ( UKY), S hyue---Ping O ng ( UCSD) ...3.5K o thers NERSC BES Requirements for 2017 October 8-9, 2013 Gaithersburg, MD Materials G enomics: Problem: Materials d iscovery i s c rucial t o a s ustainable energy f uture ( PV, b aYeries, p ermanent m agnets, cement, t hermo---electrics, c atalysis, e tc.) b ut 0 me f rom lab t o c ommercializa0on

  9. Tax Credits, Rebates & Savings | Department of Energy

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

    Technologies Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of...

  10. Laboratory support for in situ gasification reaction kinetics...

    Office of Scientific and Technical Information (OSTI)

    CARBONACEOUS MATERIALS; CHALCOGENIDES; DECOMPOSITION; ENERGY SOURCES; FOSSIL FUELS; FUELS; IN-SITU PROCESSING; KINETICS; OXIDES; OXYGEN COMPOUNDS; PROCESSING; REACTION ...

  11. Gasification of chars produced under simulated in situ processing...

    Office of Scientific and Technical Information (OSTI)

    ELECTRON MICROSCOPY; CARBONACEOUS MATERIALS; DECOMPOSITION; ENERGY SOURCES; FOSSIL FUELS; FUELS; IN-SITU PROCESSING; KINETICS; MICROSCOPY; PROCESSING; REACTION KINETICS; ...

  12. Laboratory support for in situ gasification reaction kinetics...

    Office of Scientific and Technical Information (OSTI)

    COMPOUNDS; CARBONACEOUS MATERIALS; CHALCOGENIDES; DECOMPOSITION; ENERGY SOURCES; FOSSIL FUELS; FUELS; IN-SITU PROCESSING; KINETICS; OXIDES; OXYGEN COMPOUNDS; PROCESSING; REACTION ...

  13. Gasification of chars produced under simulated in situ processing...

    Office of Scientific and Technical Information (OSTI)

    COAL; CRYOGENIC FLUIDS; DECOMPOSITION; ELEMENTS; ENERGY SOURCES; FLUIDS; FOSSIL FUELS; FUELS; GASES; GASIFICATION; HYDROCARBONS; IN-SITU PROCESSING; KINETICS; MICROSCOPY; ...

  14. Gasification of chars produced under simulated in situ processing...

    Office of Scientific and Technical Information (OSTI)

    REACTIONS; COAL GAS; GAS CHROMATOGRAPHY; HYDROGEN; METHANE; NITROGEN; SUBBITUMINOUS COAL; ... FLUIDS; DECOMPOSITION; ELEMENTS; ENERGY SOURCES; FLUIDS; FOSSIL FUELS; FUELS; ...

  15. Tax Credits, Rebates & Savings | Department of Energy

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

    wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or... Eligibility: Commercial, Industrial, Residential,...

  16. Tax Credits, Rebates & Savings | Department of Energy

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

    waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or... Eligibility: Commercial, Industrial, Residential, Agricultural,...

  17. Tax Credits, Rebates & Savings | Department of Energy

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

    decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or... Eligibility: Commercial, Industrial, Residential, Agricultural, Multifamily...

  18. Tax Credits, Rebates & Savings | Department of Energy

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

    waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or... Eligibility: Commercial, Industrial, Residential, Agricultural, Multifamily...

  19. INDDGO

    Energy Science and Technology Software Center (OSTI)

    002861MLTPL00 Integrated Network Decompositions and Dynamic Programming for Graph Optimization (INDDGO) http://github.org/bdsullivan/INDDGO

  20. NATIONAL GEOTHERMAL DATA SYSTEM (NGDS) GEOTHERMAL DATA DOMAIN: ASSESSMENT OF GEOTHERMAL COMMUNITY DATA NEEDS

    SciTech Connect (OSTI)

    Anderson, Arlene; Blackwell, David; Chickering, Cathy; Boyd, Toni; Horne, Roland; MacKenzie, Matthew; Moore, Joseph; Nickull, Duane; Richard, Stephen; Shevenell, Lisa A.

    2013-01-01

    To satisfy the critical need for geothermal data to ad- vance geothermal energy as a viable renewable ener- gy contender, the U.S. Department of Energy is in- vesting in the development of the National Geother- mal Data System (NGDS). This paper outlines efforts among geothermal data providers nationwide to sup- ply cutting edge geo-informatics. NGDS geothermal data acquisition, delivery, and methodology are dis- cussed. In particular, this paper addresses the various types of data required to effectively assess geother- mal energy potential and why simple links to existing data are insufficient. To create a platform for ready access by all geothermal stakeholders, the NGDS in- cludes a work plan that addresses data assets and re- sources of interest to users, a survey of data provid- ers, data content models, and how data will be ex- changed and promoted, as well as lessons learned within the geothermal community.

  1. Reliable Viscosity Calculation from Equilibrium Molecular Dynamics

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

    Simulations: A Time Decomposition Method - Joint Center for Energy Storage Research July 7, 2015, Research Highlights Reliable Viscosity Calculation from Equilibrium Molecular Dynamics Simulations: A Time Decomposition Method Schematic demonstration of the time decomposition method Scientific Achievement An equilibrium molecular dynamics-based computational method is developed and tested for the reliable calculation of viscosity. Significance and Impact Viscosity is one of the key properties

  2. Slide 1

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

    Principles Simulation and Model-Driven Isotopic Labeling Experiments Reveal Biomass Decomposition Pathways 1 Theory driven experimental confirmation Intensity (arb. units) 600 550 500 450 400 350 300 250 Temperature (K) H 2 (2amu) background DOCH 2 CH 2 OD HOCD 2 CD 2 OH 398K 322K 346K 432K (A) * Density functional theory (DFT) calculations of ethylene glycol decomposition on Pt(111) and Ni/Pt(111) reveal key differences between decomposition of highly functionalized oxygenates compared to

  3. Supporting Advanced Scientific Computing Research * Basic Energy Sciences * Biological

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

    Energy S ciences N etwork Enabling Virtual Science June 9, 2009 Steve C o/er steve@es.net Dept. H ead, E nergy S ciences N etwork Lawrence B erkeley N aDonal L ab The E nergy S ciences N etwork The D epartment o f E nergy's O ffice o f S cience i s o ne o f t he l argest s upporters o f basic r esearch i n t he p hysical s ciences i n t he U .S. * Directly s upports t he r esearch o f s ome 1 5,000 s cienDsts, p ostdocs a nd g raduate s tudents at D OE l aboratories, u niversiDes, o ther F

  4. Nanosecond Time Resolved and Steady State Infrared Studies of...

    Office of Scientific and Technical Information (OSTI)

    Nanosecond Time Resolved and Steady State Infrared Studies of Photoinduced Decomposition of TATB at Ambient and Elevated Pressures Citation Details In-Document Search Title: ...

  5. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in...

  6. Tax Credits, Rebates & Savings | Department of Energy

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

    of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or......

  7. What Does? Scalable Resilience? Look Like

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

    Models 4 A Runtime System based on Over-decomposition and Migratability can support resilience effetively Runtime Systems can play a role * RTS based solutions to resilience are...

  8. Tax Credits, Rebates & Savings | Department of Energy

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

    Fuels, Microturbines Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of...

  9. Tax Credits, Rebates & Savings | Department of Energy

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

    Hydroelectric (Small) Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of...

  10. Lead Hexacyanoferrate(II) Tetrahydrate: Crystal Structure, FTIR...

    Office of Scientific and Technical Information (OSTI)

    Lead Hexacyanoferrate(II) Tetrahydrate: Crystal Structure, FTIR Spectroscopy and Thermal Decomposition Studies Citation Details In-Document Search Title: Lead Hexacyanoferrate(II) ...

  11. The microbe-mediated mechanisms affecting topsoil carbon stock...

    Office of Scientific and Technical Information (OSTI)

    affecting topsoil carbon stock in Tibetan grasslands Warming has been shown to cause soil carbon (C) loss in northern grasslands owing to accelerated microbial decomposition...

  12. Reduced Order Modeling of the Forward Eigenvalue Problem

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

    reduction, the proper orthogonal decomposition 1, with a range finding algorithm from linear algebra to reduce the dimensionality of the state space 2. This results in...

  13. Tax Credits, Rebates & Savings | Department of Energy

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

    Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small...

  14. untitled

    Office of Scientific and Technical Information (OSTI)

    SCIENTIFIC REPORTS Q OPEN SUBJECT AREAS: MICROBIAL ECOLOGY THEORETICAL ECOLOGY ECOLOGICAL ... via decomposition of plant residues SCIENTIFIC REPORTS | 5 : 9575 | DOI: 10.1038...

  15. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Microscopic Origin of the Reduced Thermal Conductivity of Silicon Nanowires He, Yuping ; ... G W calculations using the spectral decomposition of the dielectric matrix: Verification, ...

  16. Search for: All records | DOE PAGES

    Office of Scientific and Technical Information (OSTI)

    ... Microscopic Origin of the Reduced Thermal Conductivity of Silicon Nanowires He, Yuping ; ... G W calculations using the spectral decomposition of the dielectric matrix: Verification, ...

  17. ARM - Publications: Science Team Meeting Documents: Advantages...

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

    an alternative T-mode decomposition. Whereas S-mode representation analyzes a dispersion matrix of inter-station covariancescorrelations, T-mode analysis transposes the...

  18. Renewable Energy Systems Exemption

    Broader source: Energy.gov [DOE]

    Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or...

  19. Tax Credits, Rebates & Savings | Department of Energy

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

    forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission...

  20. Tax Credits, Rebates & Savings | Department of Energy

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

    Geothermal Direct-Use Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of...

  1. Tax Credits, Rebates & Savings | Department of Energy

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

    Cells using Renewable Fuels Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of...

  2. A New Approach in Urea Dosing to Improve Performance and Durability of SCR Systems for the Use in Off-Road Applications to Fulfill Tier 4 Final

    Broader source: Energy.gov [DOE]

    Evaluation of influence of spray quality on urea decomposition and catalyst performance leads to new approach in dosing, using special nozzle and air-supply strategy

  3. Mechanism of Hydrogen Formation in Solar Paraboic Trough Receivers

    SciTech Connect (OSTI)

    Moens, L.; Blake, D.

    2008-02-01

    Technical report that provides an overview of the chemical literature dealing with the thermal decomposition of diphenyl oxide and biphenyl, the two constituents of Therminol VP-1.

  4. Tax Credits, Rebates & Savings | Department of Energy

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

    passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or... Eligibility: Commercial, Industrial, Residential,...

  5. Method for making boron carbide cermets

    DOE Patents [OSTI]

    Cline, Carl F.; Fulton, Fred J.

    1987-01-01

    A method for synthesizing low density cermets of boron carbide and a metal binder, using decomposition of a metallic compound at controlled temperature and pressure.

  6. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... decomposition of water into hydrogen gas using ultraviolet and visible solar radiation. ... TaON is considered as a potential candidate as a visible-light responsive photocatalyst. ...

  7. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Additionally, ethanol yields from a Simultaneous Saccharification and Fermentation process ... kinetic predictions: A case study of ethanol decomposition Xing, Lili ; Li, Shuang ; ...

  8. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Our spectral decomposition into ionic and different water solvation shell contributions ... At the same time they have developed a reputation for being hard to predict with ...

  9. Tax Credits, Rebates & Savings | Department of Energy

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

    Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal,...

  10. Process for remediation of plastic waste

    DOE Patents [OSTI]

    Pol, Vilas G; Thiyagarajan, Pappannan

    2013-11-12

    A single step process for degrading plastic waste by converting the plastic waste into carbonaceous products via thermal decomposition of the plastic waste by placing the plastic waste into a reactor, heating the plastic waste under an inert or air atmosphere until the temperature of about 700.degree. C. is achieved, allowing the reactor to cool down, and recovering the resulting decomposition products therefrom. The decomposition products that this process yields are carbonaceous materials, and more specifically carbon nanotubes having a partially filled core (encapsulated) adjacent to one end of the nanotube. Additionally, in the presence of a transition metal compound, this thermal decomposition process produces multi-walled carbon nanotubes.

  11. Process for remediation of plastic waste

    DOE Patents [OSTI]

    Pol, Vilas G.; Thiyagarajan, Pappannan

    2012-04-10

    A single step process for degrading plastic waste by converting the plastic waste into carbonaceous products via thermal decomposition of the plastic waste by placing the plastic waste into a reactor, heating the plastic waste under an inert or air atmosphere until the temperature of 700.degree. C. is achieved, allowing the reactor to cool down, and recovering the resulting decomposition products therefrom. The decomposition products that this process yields are carbonaceous materials, and more specifically egg-shaped and spherical-shaped solid carbons. Additionally, in the presence of a transition metal compound, this thermal decomposition process produces multi-walled carbon nanotubes.

  12. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... LLC New Brunswick Laboratory (NBL), Argonne, IL (United States) New York ... (1) corrosion (1) decomposition (1) evaluation (1) flowsheets (1) forecasting (1) ...

  13. Consortium for Advanced Simulation of Light Water Reactors (CASL...

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

    The toolkit also provides run-time parallel domain decomposition with data-migration for both static and dynamic load-balancing. Linear algebra is handled through an...

  14. New Title

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

    ... and industrial applications and Vision 21 energy plants. ... of "mass customization" as the route to reducing costs. ... Decomposition Reforming Methods SECA Proceedings June 2000 ...

  15. Tax Credits, Rebates & Savings | Department of Energy

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

    Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants,...

  16. Tax Credits, Rebates & Savings | Department of Energy

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

    Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal,...

  17. Tax Credits, Rebates & Savings | Department of Energy

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

    Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants,...

  18. Tax Credits, Rebates & Savings | Department of Energy

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

    Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small...

  19. Tax Credits, Rebates & Savings | Department of Energy

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

    Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower...

  20. Task Technical Plan for Studies of Oxygen Consumption in the Catalyzed Hydrolysis of Tetraphenylborate Ion

    SciTech Connect (OSTI)

    Fink, S.D.

    1996-12-20

    This document presents the plan for studies of how dissolved oxygen affects the catalytic decomposition of the tetraphenylborate ion in alkaline aqueous solution.

  1. Tax Credits, Rebates & Savings | Department of Energy

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

    using Renewable Fuels Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of...

  2. Tax Credits, Rebates & Savings | Department of Energy

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

    Renewable Energy Systems Exemption Recognized forms of energy generation include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes,...

  3. Molecular Theory of Detonation Initiation: Insight from First...

    Office of Scientific and Technical Information (OSTI)

    decomposition of molecules and materials containing defects. ... Additional Journal Information: Journal Volume: 21; Journal Issue: 2; Journal ID: ISSN 1420-3049 Publisher: MDPI Research ...

  4. Tax Credits, Rebates & Savings | Department of Energy

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

    include solar photovoltaics, passive solar, wind, solid waste, decomposition of organic wastes, geothermal, small hydropower plants, low-emission wood or... Eligibility:...

  5. SUSANA MARTINEZ Governor JOHN A. SANCHEZ Lieutenant Governor

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

    ENVlRONMENTDEPARTMENT Hazardous Waste Bureau 2905 Rodeo Park Drive East, Building 1 Santa Fe, New Mexico 87505-6303 Phone (505) 476-6000 Fax (505) 476-6030 IVww.nmenv.state.nm.us DAVE MARTIN Secretary BUTCH TONGATE Deputy Secretary CERTIFIED MAlL - RETURN RECEIPT REQUESTED May 30,2012 Jose R. Franco, Manager Carlsbad Field Office Department of Energy P. O. Box 3090 Carlsbad, New Mexico 88221-3090 M. FarokSharif Washington TRU Solutions LLC P. O. Box 2078 Carlsbad, New Mexico 88221-5608 RE:

  6. pLS010 plasmid vector

    DOE Patents [OSTI]

    Lacks, Sanford A.; Balganesh, Tanjore S.

    1988-01-01

    Disclosed is recombinant plasmid pLS101, consisting essentially of a 2.0 Kb malM gene fragment ligated to a 4.4 Kb T.sub.c r DNA fragment, which is particularly useful for transforming Gram-positive bacteria. This plasmid contains at least four restriction sites suitable for inserting exogeneous gene sequences. Also disclosed is a method for plasmid isolation by penicillin selection, as well as processes for enrichment of recombinant plasmids in Gram-positive bacterial systems.

  7. dI UNIVERSITY OF NEV\DA SYSTEM

    Office of Legacy Management (LM)

    g3t4 6 dI UNIVERSITY OF NEV\DA SYSTEM tw ?r@ D O E / D P / O 1 2 6 3 - 2 0 L , n z l t P ' " WATER RESOURCES CENTER itf.l This report was prepared as an aecount of work sponsore$ by the United States Government. Neither the United States nor the United States Department of Energy, nor any of their employees, mal assumes any legal liability or responsib usefulness of any informationr apparatus' I that its use would not infringe privately speeifie eommereial produetr proeesst ufacturen, or

  8. Introduction

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

    diverse and complex mosaic of plant and animal communities are found at the Nevada National Security Site. Representative of both the Mojave and Great Basin deserts, approximately 1,500 ani- mal species, including 924 species of insects, and 750 different kinds of plants are documented at the site. The varying elevations and climatic conditions at the test site contribute to the distribution of plant and animal communities. On the south end of the site, Jackass Flats lies at a low 2,688 feet

  9. Purification of Hydrogen

    DOE Patents [OSTI]

    Newton, A S

    1950-12-05

    Disclosed is a process for purifying hydrogen containing various gaseous impurities by passing the hydrogen over a large surface of uranium metal at a temperature above the decomposition temperature of uranium hydride, and below the decomposition temperature of the compounds formed by the combination of the uranium with the impurities in the hydrogen.

  10. Method of manufacturing aerogel composites

    DOE Patents [OSTI]

    Cao, Wanqing; Hunt, Arlon Jason

    1999-01-01

    Disclosed herewith is a process of forming an aerogel composite which comprises introducing a gaseous material into a formed aerogel monolith or powder, and causing decomposition of said gaseous material in said aerogel in amounts sufficient to cause deposition of the decomposition products of the gas on the surfaces of the pores of the said aerogel.

  11. Method of manufacturing aerogel composites

    DOE Patents [OSTI]

    Cao, W.; Hunt, A.J.

    1999-03-09

    Disclosed herewith is a process of forming an aerogel composite which comprises introducing a gaseous material into a formed aerogel monolith or powder, and causing decomposition of said gaseous material in said aerogel in amounts sufficient to cause deposition of the decomposition products of the gas on the surfaces of the pores of the said aerogel.

  12. Method and apparatus for maintaining the pH in zinc-bromine battery systems

    DOE Patents [OSTI]

    Grimes, Patrick G.

    1985-09-10

    A method and apparatus for maintaining the pH level in a zinc-bromine battery features reacting decomposition hydrogen with bromine in the presence of a catalyst. The catalyst encourages the formation of hydrogen and bromine ions. The decomposition hydrogen is therefore consumed, alloying the pH of the system to remain substantially at a given value.

  13. Benzene distribution in product streams from in-tank processing

    SciTech Connect (OSTI)

    Walker, D.D.

    1987-01-15

    Benzene is the major product of radiolytic decomposition of tetraphenylborate salts during in-tank salt decontamination. Its production rate has been measured at the Savannah River Laboratory (SR) and at the University of Florida under various conditions of importance to the in-tank process. Recent work has been concerned with the extent of decomposition for long storage periods, and the composition of the product streams from the process. The major results from this work are: the stored potassium tetraphenylborate precipitate will decompose at a rate of 7.3 {plus minus} 1.1% per year; the major products of the decomposition are benzene, phenol, biphenyl, and phenylboric acid; decomposition is directly proportional to the total dose and is unaffected by dose rate; the decomposition produces acidic compounds which will cause a decrease in the pH of the storage tank. 13 refs., 6 figs., 6 tabs.

  14. Evaluation of global horizontal irradiance to plane-of-array irradiance models at locations across the United States

    SciTech Connect (OSTI)

    Lave, Matthew; Hayes, William; Pohl, Andrew; Hansen, Clifford W.

    2015-02-02

    We report an evaluation of the accuracy of combinations of models that estimate plane-of-array (POA) irradiance from measured global horizontal irradiance (GHI). This estimation involves two steps: 1) decomposition of GHI into direct and diffuse horizontal components and 2) transposition of direct and diffuse horizontal irradiance (DHI) to POA irradiance. Measured GHI and coincident measured POA irradiance from a variety of climates within the United States were used to evaluate combinations of decomposition and transposition models. A few locations also had DHI measurements, allowing for decoupled analysis of either the decomposition or the transposition models alone. Results suggest that decomposition models had mean bias differences (modeled versus measured) that vary with climate. Transposition model mean bias differences depended more on the model than the location. Lastly, when only GHI measurements were available and combinations of decomposition and transposition models were considered, the smallest mean bias differences were typically found for combinations which included the Hay/Davies transposition model.

  15. Relation between combustion heat and chemical wood composition during white and brown rot

    SciTech Connect (OSTI)

    Dobry, J.; Dziurzynski, A.; Rypacek, V.

    1986-01-01

    Samples of beech and spruce wood were incubated with the white rot fungi Pleurotus ostreatus and Lentinus tigrinus and the brown rot fungi Fomitopsis pinicola and Serpula lacrymans (S. lacrimans) for four months. Decomposition (expressed as percent weight loss) and amounts of holocellulose, lignin, humic acids (HU), hymatomelanic acids (HY) and fulvo acids (FU) were determined and expressed in weight percent. Combustion heat of holocellulose and lignin was determined in healthy wood and in specimens where decomposition was greater than 50%. During white rot decomposition, combustion heat was unchanged even at high decomposition and the relative amounts of holocellulose and lignin remained the same. Total amounts of HU, HY and FU increased during the initial stages and stabilized at 20%. The content of HU plus HY was negligible even at the highest degree of decomposition. During brown rot decomposition, combustion heat was unchanged only in the initial stages, it increased continously with increasing rot. Lignin content was unchanged in the initial stages and increased after 30% weight loss. Total amounts of HU, HY and FU increased continuously, reaching higher values than in white rot decomposition; there were differences between the two species. Biosynthesis of HU plus HY began when weight loss reached 30%; there were differences in absolute and relative amounts between species. 24 references.

  16. A Window on Surface Explosions: Tartaric Acid on Cu(110)

    SciTech Connect (OSTI)

    Mhatre, B. S.; Pushkarev, V.; Holsclaw, B.; Lawton, T. J.; Sykes, E. C. H.; Gellman, A. J.

    2013-04-18

    Autocatalytic reaction mechanisms are observed in a range of important chemical processes including catalysis, radical-mediated explosions, and biosynthesis. Because of their complexity, the microscopic details of autocatalytic reaction mechanisms have been difficult to study on surfaces and heterogeneous catalysts. Autocatalytic decomposition reactions of S,S- and R,R-tartaric acid (TA) adsorbed on Cu(110) offer molecular-level insight into aspects of these processes, which until now, were largely a matter of speculation. The decomposition of TA/Cu(110) is initiated by a slow, irreversible process that forms vacancies in the adsorbed TA layer, followed by a vacancy-mediated, explosive decomposition process that yields CO{sub 2} and small hydrocarbon products. Initiation of the explosive decomposition of TA/Cu(110) has been studied by measurement of the reaction kinetics, time-resolved low energy electron diffraction (LEED), and time-resolved scanning tunneling microscopy (STM). Initiation results in a decrease in the local coverage of TA and a concomitant increase in the areal vacancy concentration. Observations of explosive TA decomposition on the Cu(651)S surface suggest that initiation does not occur at structural defects in the surface, as has been suggested in the past. Once the vacancy concentration reaches a critical value, the explosive, autocatalytic decomposition step dominates the TA decomposition rate. The onset of the explosive decomposition of TA on Cu(110) is accompanied by the extraction of Cu atoms from the surface to form a (±6,7; {-+}2,1) overlayer that is readily observable using LEED and STM. The explosive decomposition step is second-order in vacancy concentration and accelerates with increasing extent of reaction.

  17. CX-013571: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Thermal-Chemical Decomposition of Graphite CX(s) Applied: B3.6Date: 04/13/2015 Location(s): South CarolinaOffices(s): Savannah River Operations Office

  18. CX-010329: Categorical Exclusion Determination

    Office of Energy Efficiency and Renewable Energy (EERE)

    Thermal-Chemical Decomposition of Graphite CX(s) Applied: B3.6 Date: 04/04/2013 Location(s): South Carolina Offices(s): Savannah River Operations Office

  19. CX-011510: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Thermal-Chemical Decomposition of Graphite CX(s) Applied: B3.6 Date: 10/17/2013 Location(s): South Carolina Offices(s): Savannah River Operations Office

  20. Liquid composition having ammonia borane and decomposing to form hydrogen and liquid reaction product

    DOE Patents [OSTI]

    Davis, Benjamin L; Rekken, Brian D

    2014-04-01

    Liquid compositions of ammonia borane and a suitably chosen amine borane material were prepared and subjected to conditions suitable for their thermal decomposition in a closed system that resulted in hydrogen and a liquid reaction product.

  1. Porphyrins and metal complexes thereof having haloalkyl side chains

    DOE Patents [OSTI]

    Wijesekera, Tilak; Lyons, James E.; Ellis, Jr., Paul E.; Bhinde, Manoj V.

    1997-01-01

    Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides.

  2. Alkane oxidation with porphyrins and metal complexes thereof having haloalkyl side chains

    DOE Patents [OSTI]

    Wijesekera, T.; Lyons, J.E.; Ellis, P.E. Jr.; Bhinde, M.V.

    1998-06-23

    Transition metal complexes of meso-haloalkylporphyrins are disclosed, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides. 7 figs.

  3. Porphyrins and metal complexes thereof having haloalkyl side chains

    DOE Patents [OSTI]

    Wijesekera, T.; Lyons, J.E.; Ellis, P.E. Jr.; Bhinde, M.V.

    1997-03-04

    Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides. 7 figs.

  4. Alkane oxidation with porphyrins and metal complexes thereof having haloalkyl side chains

    DOE Patents [OSTI]

    Wijesekera, Tilak; Lyons, James E.; Ellis, Jr., Paul E.; Bhinde, Manoj V.

    1998-01-01

    Transition metal complexes of meso-haloalkylporphyrins, wherein the haloalkyl groups contain 2 to 8 carbon atoms have been found to be highly effective catalysts for oxidation of alkanes and for the decomposition of hydroperoxides.

  5. September 2015 Most Viewed Documents for Chemistry | OSTI, US...

    Office of Scientific and Technical Information (OSTI)

    Decomposition of calcium sulfate: a review of the literature. 62 refs Swift, W M; Panek, A F; Smith, G W; Vogel, G J; Jonke, A A (1976) 122 Electrical conductivity measurements ...

  6. September 2015 Most Viewed Documents for Fossil Fuels | OSTI...

    Office of Scientific and Technical Information (OSTI)

    Jorge Gabitto; Maria Barrufet (2003) 141 Decomposition of calcium sulfate: a review of the literature. 62 refs Swift, W M; Panek, A F; Smith, G W; Vogel, G J; Jonke, A A (1976) ...

  7. Raman Investigation of The Uranium Compounds U3O8, UF4, UH3 and...

    Office of Scientific and Technical Information (OSTI)

    They absorb the incoming radiation and quickly heat up to the point of decomposition. This has been dealt with in the past by keeping the incoming laser power to very low levels on ...

  8. Process for thermochemically producing hydrogen

    DOE Patents [OSTI]

    Bamberger, Carlos E.; Richardson, Donald M.

    1976-01-01

    Hydrogen is produced by the reaction of water with chromium sesquioxide and strontium oxide. The hydrogen producing reaction is combined with other reactions to produce a closed chemical cycle for the thermal decomposition of water.

  9. RussiaLANLV3-web.indd

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

    Heterogeneous decomposition Radius, mm 2 1 0 Radius, mm 2 1 0 Radius, mm Aluminum Copper Modifi ed for the Web The task will be performed in two stages. In the fi rst stage (fi rst ...

  10. RussiaSNL2-web.indd

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

    ... On-Line FTIR Condenser Reactor Schematic large sample thermal decomposition. Modifi ed for the Web The project has signifi cantly benefi ted USDP, ASC, and the Russian Federation, ...

  11. J

    Office of Scientific and Technical Information (OSTI)

    ... Another benefit of application of TiO2 is that the unit price of T1O2 is affordable to use ... (1.983). 16. Ahmead, S. & Ollis, D. F., "Solar Photoassisted Catalytic Decomposition of ...

  12. Harnessing the Bacterial Power of Nanomagnets

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

    and 23 atom % Co (bottom). Right: The decomposition of the XMCD spectra into the Fe2+ Oh (purple), Fe3+ Td (blue), and Fe3+ Oh (green) components. The color-coded numbers indicate...

  13. Method of depositing buffer layers on biaxially textured metal...

    Office of Scientific and Technical Information (OSTI)

    eu; gd; tb; tm; resup1subx; resup2sub1-xsub2; osub3; buffer; layer; deposited; sol-gel; metal-organic; decomposition; laminate; article; layer; ybco; resup1subx; ...

  14. CX-012288: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Development of Reduced-Order Model for Gas-Solid Flow Using Proper Orthogonal Decomposition CX(s) Applied: A9 Date: 06/05/2014 Location(s): Texas Offices(s): National Energy Technology Laboratory

  15. CX-012287: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Development of Reduced-Order Model for Gas-Solid Flow Using Proper Orthogonal Decomposition CX(s) Applied: A9 Date: 06/05/2014 Location(s): Florida Offices(s): National Energy Technology Laboratory

  16. Energy partitioning in elementary chemical processes

    SciTech Connect (OSTI)

    Bersohn, R.

    1993-12-01

    In the past year research has centered on the decomposition of hot molecules, the reaction of ethynyl radicals with hydrogen molecules and the reaction of oxygen atoms with acetylene. Reaction kinetics studies are reported for each of these systems.

  17. Flash photolysis-shock tube studies

    SciTech Connect (OSTI)

    Michael, J.V.

    1993-12-01

    Even though this project in the past has concentrated on the measurement of thermal bimolecular reactions of atomic species with stable molecules by the flash or laser photolysis-shock tube (FP- or LP-ST) method using atomic resonance absorption spectrometry (ARAS) as the diagnostic technique, during the past year the authors have concentrated on studies of the thermal decompositions of selected chlorocarbon molecules. These studies are necessary if the degradation of chlorine containing organic molecules by incineration are to be understood at the molecular level. Clearly, destruction of these molecules will not only involve abstraction reactions, when possible, but also thermal decomposition followed by secondary reactions of the initially formed atoms and radicals. Studies on the thermal decomposition of CH{sub 3}Cl are complete, and the curve-of-growth for Cl-atom atomic resonance absorption has been determined. The new thermal decomposition studies are similar to those already reported for CH{sub 3}Cl.

  18. Thermal Stability of LiPF 6 Salt and Li-ion Battery Electrolytes...

    Office of Scientific and Technical Information (OSTI)

    In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct thermal reaction between LiPF 6 and water vapor to form ...

  19. Modeling the effects of fire severity and climate warming on...

    Office of Scientific and Technical Information (OSTI)

    in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal...

  20. 836.pdf

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

    ... domain decomposition with data-migration for both static and dynamic load-balancing. ... gradient, i.e, the 'Q' criteria, processor ID (MPI rank), and tur- bulent eddy viscosity. ...

  1. Nanocatalytic Conversion of Biomass into Second-Generation Biofuels

    SciTech Connect (OSTI)

    2009-04-01

    This factsheet describes a study whose focus is on unconventional feedstocks for ansportation fuel and commodity chemicals, primarily lignin, testing novel nanocatalytic pathways for the decomposition of refractory materials into useful building block chemicals.

  2. Method for preparing thermally cleavable surfactants without deprotonation

    DOE Patents [OSTI]

    McElhanon, James R.; Jamison, Gregory M.; Long, Timothy M.; Loy, Douglas A.; Rahimian, Kamyar; Simmons, Blake A.; Staiger, Chad L.; Wheeler, David R.; Zifer, Thomas

    2008-05-27

    The present invention describes surfactants of formula (I), ##STR00001## wherein R, R.sub.N, and m are defined herein, processes for their preparation, and methods for their decomposition.

  3. Thermally cleavable surfactants without deprotonation

    DOE Patents [OSTI]

    McElhanon, James R.; Jamison, Gregory M.; Long, Timothy M.; Loy, Douglas A.; Rahimian, Kamyar; Simmons, Blake A.; Staiger, Chad L.; Wheeler, David R.; Zifer, Thomas

    2008-04-01

    The present invention describes surfactants of formula (I), ##STR00001## wherein R, R.sub.N, and m are defined herein, processes for their preparation, and methods for their decomposition.

  4. Ni-Si Alloys for the S-I Reactor-Hydrogen Production Process Interface

    SciTech Connect (OSTI)

    Joseph W. Newkirk; Richard K. Brow

    2010-01-21

    The overall goal of this project was to develop Ni-Si alloys for use in vessels to contain hot, pressurized sulfuric acid. The application was to be in the decomposition loop of the thermochemical cycle for production of hydrogen.

  5. THE LEVENBERG-MARQUARDT ALGORITHM: IMPLEMENTATION AND THEORY

    Office of Scientific and Technical Information (OSTI)

    ... p is to use Cholesky decomposition on the linear system (3.1) (JJ + XDD)p -j'f . ... and moreover, the denominator will be non-negative regardless of roundoff errors. ...

  6. Viscosity and Vorticity in Reduced Magneto-Hydrodynamics

    SciTech Connect (OSTI)

    Joseph, Ilon

    2015-08-12

    Magneto-hydrodynamics (MHD) critically relies on viscous forces in order for an accurate determination of the electric eld. For each charged particle species, the Braginskii viscous tensor for a magnetized plasma has the decomposition into matrices with special symmetries.

  7. Thermal Hydraulic Modeling: Cross-Verification, Validation, and...

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

    ... Wire in a Channel Proper Orthogonal Decomposition of the Flow in a T-Junction (In: Advances in Nuclear Power Plants) Optimal Disturbances in Three-Dimensional Natural Convection ...

  8. Adventures on the C3H5O potential energy surface: OH+propyne...

    Office of Scientific and Technical Information (OSTI)

    for the bimolecular reactions propyne + OH and allene + OH, and for the unimolecular decomposition of the CH3CCHOH, CH3C(OH)CH, CH2CCH2OH, CH2C(OH)CH2 primary adducts, ...

  9. Dynamic and Adaptive Parallel Programming for Exascale Research | Argonne

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

    Leadership Computing Facility Sample multi-resolution adaptive decomposition of a function and flow of data associated with compression of the representation. Sample multi-resolution adaptive decomposition of a function and flow of data associated with compression of the representation. The example is in one dimension but practical applications are typically in three, four, five and even six dimensions. Robert Harrison, Stony Brook University Dynamic and Adaptive Parallel Programming for

  10. Solution mining dawsonite from hydrocarbon containing formations with a chelating agent

    DOE Patents [OSTI]

    Vinegar, Harold J. (Bellaire, TX)

    2009-07-07

    A method for treating an oil shale formation comprising dawsonite includes providing heat from one or more heaters to the formation to heat the formation. Hydrocarbon fluids are produced from the formation. At least some dawsonite in the formation is decomposed with the provided heat. A chelating agent is provided to the formation to dissolve at least some dawsonite decomposition products. The dissolved dawsonite decomposition products are produced from the formation.

  11. Heavy oil/plastic co-processing - subtask 4.1. Topical report, February 1, 1994--February 1, 1995

    SciTech Connect (OSTI)

    1998-12-31

    Western Research Institute (WRI) is developing a low-temperature thermal decomposition process to alleviate the problems associated with disposal of waste plastics and at the same time generate a product stream in the gasoline boiling range for use in the refining and petrochemical industries. The technology being developed by WRI is significantly different from conventional thermal decomposition processes used to recover distillates from waste plastics. The key to this difference is the application of a decomposition initiator concept that allows operation of the process at temperatures below those used in other thermal decomposition processes. The WRI technology utilizes the decomposition initiator to enhance thermal decomposition of waste plastics in the presence of a low-value heavy oil at temperatures below those normally used for thermal decomposition. Operation of the process at lower temperatures produces higher yields of distillate product and lower yields of gaseous and char products than conventional processes. The activity of the initiator was identified in earlier research studying the thermal decomposition of polymers. This activity was observed to result in a decrease in the temperature required to thermally decompose plastics in the presence of a heavy oil. These early experiments indicated that the initiator was native to the plastics matrix, but the identity and possible mode of action were not determined. This study was undertaken to identify the active initiator in the plastics matrix and define its activity. The experiments performed in this study were conducted in a batch-type reactor. The particular elements of the activity that were addressed included: (1) the kinetics of the reaction, (2) the effects of diluting the plastics with the heavy oil, and (3) the effects of using different types of heavy oil.

  12. ACTUAL-WASTE TESTING OF ULTRAVIOLET LIGHT TO AUGMENT THE ENHANCED CHEMICAL CLEANING OF SRS SLUDGE

    SciTech Connect (OSTI)

    Martino, C.; King, W.; Ketusky, E.

    2012-07-10

    In support of Savannah River Site (SRS) tank closure efforts, the Savannah River National Laboratory (SRNL) conducted Real Waste Testing (RWT) to evaluate Enhanced Chemical Cleaning (ECC), an alternative to the baseline 8 wt% oxalic acid (OA) chemical cleaning technology for tank sludge heel removal. ECC utilizes a more dilute OA solution (2 wt%) and an oxalate destruction technology using ozonolysis with or without the application of ultraviolet (UV) light. SRNL conducted tests of the ECC process using actual SRS waste material from Tanks 5F and 12H. The previous phase of testing involved testing of all phases of the ECC process (sludge dissolution, OA decomposition, product evaporation, and deposition tank storage) but did not involve the use of UV light in OA decomposition. The new phase of testing documented in this report focused on the use of UV light to assist OA decomposition, but involved only the OA decomposition and deposition tank portions of the process. Compared with the previous testing at analogous conditions without UV light, OA decomposition with the use of UV light generally reduced time required to reach the target of <100 mg/L oxalate. This effect was the most pronounced during the initial part of the decomposition batches, when pH was <4. For the later stages of each OA decomposition batch, the increase in OA decomposition rate with use of the UV light appeared to be minimal. Testing of the deposition tank storage of the ECC product resulted in analogous soluble concentrations regardless of the use or non-use of UV light in the ECC reactor.

  13. 2013 DOE Bioenergy Technologies Office (BETO) Project Peer Review

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

    Hydrothermal Decomposition & Resource Recycling Date: May 21 st , 2013 Technology Area Review: BETO Principal Investigator: City of Allentown & Delta Thermo Energy Organization: City of Allentown This presentation does not contain any proprietary, confidential, or otherwise restricted information Goal Statement * Research & design an innovative solution using "Hydrothermal Decomposition" technology to transform municipal solid waste, biomass, biosolids waste into a

  14. PROCESS FOR CONTROLLING ANIMAL GROWTH RATE

    DOE Patents [OSTI]

    Visek, W.J.

    1962-04-10

    A method of injecting growing animals with the enzyme urease subcutaneously in increasing dosages is described; this generates within the blood anti-urease which enters the intestinal tract and inhibits the enzymatic decomposition of urea by urease in that location. Ammonia, one of the decomposition products, is thereby kept from diffusing through the intestinal walls into the blood, and this greatly reduces the energy requirements of the liver for removing the ammonia, thereby increasing the feeding efficiency of the animals. (AEC)

  15. Slide 1

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

    obtain an accurate force field for Metal Organic Frameworks (MOF) with open metal sites from quantum chemical calculations Significance and Impact This method allows the prediction of the thermodynamic and transport data of these MOFS from structural data Research Details - Development of the force field is based on the NEMO approach which allows the decomposition of the total energy into different contributions: repulsion, attraction, and electrostatic. - This decomposition allows the fitting

  16. Aerogel composites and method of manufacture

    DOE Patents [OSTI]

    Cao, Wanqing (Alameda, CA); Hunt, Arlon Jason (Oakland, CA)

    1999-01-01

    Disclosed herewith is a process of forming an aerogel composite which comprises introducing a gaseous material into a formed aerogel monolith or powder, and causing decomposition of said gaseous material in said aerogel in amounts sufficient to cause deposition of the decomposition products of the gas on the surfaces of the pores of the said aerogel. Also disclosed are the composites made by the process.

  17. Anaerobic High-Throughput Cultivation Method for Isolation of Thermophiles Using Biomass-Derived Substrates

    SciTech Connect (OSTI)

    Hamilton-Brehm, Scott; Vishnivetskaya, Tatiana A; Allman, Steve L; Mielenz, Jonathan R; Elkins, James G

    2012-01-01

    Flow cytometry (FCM) techniques have been developed for sorting mesophilic organisms, but the difficulty increases if the target microbes are thermophilic anaerobes. We demonstrate a reliable, high-throughput method of screening thermophilic anaerobic organisms using FCM and 96-well plates for growth on biomass-relevant substrates. The method was tested using the cellulolytic thermophiles Clostridium ther- mocellum (Topt = 55 C), Caldicellulosiruptor obsidiansis (Topt = 78 C) and the fermentative hyperthermo- philes, Pyrococcus furiosus (Topt = 100 C) and Thermotoga maritima (Topt = 80 C). Multi-well plates were incubated at various temperatures for approximately 72 120 h and then tested for growth. Positive growth resulting from single cells sorted into individual wells containing an anaerobic medium was verified by OD600. Depending on the growth substrate, up to 80 % of the wells contained viable cultures, which could be transferred to fresh media. This method was used to isolate thermophilic microbes from Rabbit Creek, Yellowstone National Park (YNP), Wyoming. Substrates for enrichment cultures including crystalline cellulose (Avicel), xylan (from Birchwood), pretreated switchgrass and Populus were used to cultivate organisms that may be of interest to lignocellulosic biofuel production.

  18. Magnetic structure of the antiferromagnetic Kondo lattice compounds CeRhAl4Si2 and CeIrAl4Si2

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

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

    2015-06-01

    In this article, we have investigated the magnetic ground state of the antiferromagnetic Kondo-lattice compounds CeMAl4Si2(M = Rh, Ir) using neutron powder diffraction. Although both of these compounds show two magnetic transitions TN1 and TN2 in the bulk properties measurements, evidence for magnetic long-range order was only found below the lower transition TN2. Analysis of the diffraction profiles reveals a commensurate antiferromagnetic structure with a propagation vector k = (0, 0, 1/2). The magnetic moment in the ordered state of CeRhAl4Si2 and CeIrAl4Si2 were determined to be 1.14(2) and 1.41(3) μB/Ce, respectively, and are parallel to the crystallographic c-axis inmore » agreement with magnetic susceptibility measurements.« less

  19. DIFFERENTIAL SPECTRUM OF NEUTRONS AT CHACALTAYA-BOLIVIA

    SciTech Connect (OSTI)

    Mayta, R.; Zanini, A.; Ticona, R.; Velarde, A.

    2009-04-30

    We describe the Neutron Spectrometer Experiment installed at Chacaltaya Cosmic Rays Observatory (68 deg. O, 16.2 deg. S), located in Bolivia, at 5230 m.a.s.l. This experimental system is constituted by passive detectors which register the flux of neutrons, in an energy range of 10 KeV-20 MeV. Using the unfolding code BUNTO a peak around 1 MeV of the characteristic spectrum of neutrons was obtained. Experimental values, observed during April of 2008, are compared with similar ones carried out in 1997 at the same place, in order to look for eventual changes due to local atmosphere. A similar experiment was also carried up at the Laboratory of Testa Grigia-Italy (45.56 deg. N, 7.42 deg. E,. 3480 m.a.l.s). Data of both stations allow us to compare the spectra in order to explain the difference of neutron flux of these two stations.

  20. Reversible hydrogen storage materials

    DOE Patents [OSTI]

    Ritter, James A.; Wang, Tao; Ebner, Armin D.; Holland, Charles E.

    2012-04-10

    In accordance with the present disclosure, a process for synthesis of a complex hydride material for hydrogen storage is provided. The process includes mixing a borohydride with at least one additive agent and at least one catalyst and heating the mixture at a temperature of less than about 600.degree. C. and a pressure of H.sub.2 gas to form a complex hydride material. The complex hydride material comprises MAl.sub.xB.sub.yH.sub.z, wherein M is an alkali metal or group IIA metal, Al is the element aluminum, x is any number from 0 to 1, B is the element boron, y is a number from 0 to 13, and z is a number from 4 to 57 with the additive agent and catalyst still being present. The complex hydride material is capable of cyclic dehydrogenation and rehydrogenation and has a hydrogen capacity of at least about 4 weight percent.

  1. CILJCU~ATI, QUO J. A. Qu~glw, M

    Office of Legacy Management (LM)

    lo&&-, : i e r : gtdlm FILLS March 12, 1956 ~'RII~~~~~I~~D~.,A~ICAW~~TMDRLBS, CILJCU~ATI, QUO J. A. Qu~glw, M .D. c. E. aahwun ObJcrativr oi THpt On !iUesd8y, Fabmerg 28,19!36, th@ lILQMetallurgMalD@p~rtJmnt beipn bzdquotting green ult-ll( blend on e 350 ton hydmulla prau 8t the Ura &i&nnrlug DivUiou of Ameria8n Steel muUdPae8, c&alMatl, Ohio. Approll'tely a,ooo pound8 of greeu ult ub briqumtte4 bw13ry 8 -rioa of mvea day,. Par the pwpou ofwalutlngexpo88mmmafpemmm8 linrelvmd

  2. Static and dynamic pressure effects on the thermolysis of nitroalkanes in solution

    SciTech Connect (OSTI)

    Brower, K.R. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Chemistry; Davis, L.L.; Naud, D.L. [Los Alamos National Lab., NM (United States); Wang, J. [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemistry

    1998-12-31

    The authors have measured the effects of static and shock-induced pressures on the decomposition rates and mechanisms of various nitroalkanes dissolved in different solvents with and without organic amine catalysts. While nitroalkanes without {alpha}-hydrogen decompose by homolysis of the C-NO{sub 2} bond over a wide range of conditions, the decomposition pathway of nitroalkanes having {alpha}-hydrogens (i.e., acidic nitroalkanes) is complicated and follows different decomposition mechanisms depending on the availability of organic base and reaction pressure. The Nef reaction is also an important reaction pathway. The five known decomposition pathways, homolysis of the C-NO{sub 2} bond, bimolecular reaction between the aci-form and aci-ion, cyclization of the aci-form, elimination of nitrous acid, and the Nef reaction, are highly dependent on the reaction conditions, such as pressure, presence of organic amines, water, alcohols, and polarity of solvent. The authors discuss the results of several tests used to support these various decomposition mechanisms.

  3. Parallel Atomistic Simulations

    SciTech Connect (OSTI)

    HEFFELFINGER,GRANT S.

    2000-01-18

    Algorithms developed to enable the use of atomistic molecular simulation methods with parallel computers are reviewed. Methods appropriate for bonded as well as non-bonded (and charged) interactions are included. While strategies for obtaining parallel molecular simulations have been developed for the full variety of atomistic simulation methods, molecular dynamics and Monte Carlo have received the most attention. Three main types of parallel molecular dynamics simulations have been developed, the replicated data decomposition, the spatial decomposition, and the force decomposition. For Monte Carlo simulations, parallel algorithms have been developed which can be divided into two categories, those which require a modified Markov chain and those which do not. Parallel algorithms developed for other simulation methods such as Gibbs ensemble Monte Carlo, grand canonical molecular dynamics, and Monte Carlo methods for protein structure determination are also reviewed and issues such as how to measure parallel efficiency, especially in the case of parallel Monte Carlo algorithms with modified Markov chains are discussed.

  4. Handling of Ammonium Nitrate Mother-Liquid Radiochemical Production - 13089

    SciTech Connect (OSTI)

    Zherebtsov, Alexander; Dvoeglazov, Konstantine; Volk, Vladimir; Zagumenov, Vladimir; Zverev, Dmitriy; Tinin, Vasiliy; Kozyrev, Anatoly; Shamin, Dladimir; Tvilenev, Konstantin

    2013-07-01

    The aim of the work is to develop a basic technology of decomposition of ammonium nitrate stock solutions produced in radiochemical enterprises engaged in the reprocessing of irradiated nuclear fuel and fabrication of fresh fuel. It was necessary to work out how to conduct a one-step thermal decomposition of ammonium nitrate, select and test the catalysts for this process and to prepare proposals for recycling condensation. Necessary accessories were added to a laboratory equipment installation decomposition of ammonium nitrate. It is tested several types of reducing agents and two types of catalyst to neutralize the nitrogen oxides. It is conducted testing of modes of the process to produce condensation, suitable for use in the conversion of a new technological scheme of production. It is studied the structure of the catalysts before and after their use in a laboratory setting. It is tested the selected catalyst in the optimal range for 48 hours of continuous operation. (authors)

  5. Thermal shock resistance ceramic insulator

    DOE Patents [OSTI]

    Morgan, Chester S. (Oak Ridge, TN); Johnson, William R. (Maynardville, TN)

    1980-01-01

    Thermal shock resistant cermet insulators containing 0.1-20 volume % metal present as a dispersed phase. The insulators are prepared by a process comprising the steps of (a) providing a first solid phase mixture of a ceramic powder and a metal precursor; (b) heating the first solid phase mixture above the minimum decomposition temperature of the metal precursor for no longer than 30 minutes and to a temperature sufficiently above the decomposition temperature to cause the selective decomposition of the metal precursor to the metal to provide a second solid phase mixture comprising particles of ceramic having discrete metal particles adhering to their surfaces, said metal particles having a mean diameter no more than 1/2 the mean diameter of the ceramic particles, and (c) densifying the second solid phase mixture to provide a cermet insulator having 0.1-20 volume % metal present as a dispersed phase.

  6. Flammable Gas Safety Program: Mechanisms of gas generation from simulated SY Tank Farm wastes. Progress report, FY 1994

    SciTech Connect (OSTI)

    Barefield, E.K.; Boadtright, D.; Deshpande, A.; Doctorovich, F.; Liotta, C.L.; Neumann, H.M.; Seymore, S.

    1995-09-01

    This is the final report for work done at Georgia Tech during Fiscal Year 1994. The objectives of this work were to develop a better understanding of the mechanism of formation of flammable gases in the thermal decomposition of metal complexants, such as HEDTA and sodium glycolate, in simulated SY waste mixtures. This project is a continuation of work begun under earlier contracts with Westinghouse Hanford Co. Three major areas are discussed: development of a reliable analysis for dissolved ammonia, the initiation of long term studies of HEDTA decomposition in stainless steel vessels and product analyses through 3800 h, and further consideration of product analyses and kinetic data reported in FY 1993 for decomposition of HEDTA and sodium glycolate in Teflon-lined glass vessels. A brief exploration was also made of the speciation of aluminum(l1l) in the presence of HEDTA as a function of pH using {sup 27}Al NMR.

  7. Method for the decontamination of soil containing solid organic explosives therein

    DOE Patents [OSTI]

    Radtke, Corey W.; Roberto, Francisco F.

    2000-01-01

    An efficient method for decontaminating soil containing organic explosives ("TNT" and others) in the form of solid portions or chunks which are not ordinarily subject to effective bacterial degradation. The contaminated soil is treated by delivering an organic solvent to the soil which is capable of dissolving the explosives. This process makes the explosives more bioavailable to natural bacteria in the soil which can decompose the explosives. An organic nutrient composition is also preferably added to facilitate decomposition and yield a compost product. After dissolution, the explosives are allowed to remain in the soil until they are decomposed by the bacteria. Decomposition occurs directly in the soil which avoids the need to remove both the explosives and the solvents (which either evaporate or are decomposed by the bacteria). Decomposition is directly facilitated by the solvent pre-treatment process described above which enables rapid bacterial remediation of the soil.

  8. Survey of systolic arrays for signal processing

    SciTech Connect (OSTI)

    Speiser, J.M.; Whitehouse, H.J.

    1983-01-01

    This paper reviews the major computational requirements for modern signal processing and surveys recent progress in parallel processing algorithms and architectures for their real-time implementation. The five matrix operations listed may be computed noniteratively, and systolic array architectures and algorithms are available which provide modular parallelism. Parallel computation of eigensystems, generalized eigensystems, the singular value decomposition, and the generalized singular value decomposition is more difficult, since the computation is necessarily iterative, and it is difficult to utilize only local communication between processing elements while maintaining high efficiency. Algorithms for the latter problems are therefore still the subject of intensive research. 33 references.

  9. Matrix Methods for Estimating the Coherence Functions from Estimates of the Cross-Spectral Density Matrix

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

    Smallwood, D. O.

    1996-01-01

    It is shown that the usual method for estimating the coherence functions (ordinary, partial, and multiple) for a general multiple-input! multiple-output problem can be expressed as a modified form of Cholesky decomposition of the cross-spectral density matrix of the input and output records. The results can be equivalently obtained using singular value decomposition (SVD) of the cross-spectral density matrix. Using SVD suggests a new form of fractional coherence. The formulation as a SVD problem also suggests a way to order the inputs when a natural physical order of the inputs is absent.

  10. REDUCTION OF ACIDITY OF NITRIC ACID SOLUTIONS BY USE OF FORMALDEHYDE

    DOE Patents [OSTI]

    Healy, T.V.

    1958-05-20

    A continuous method is described of concentrating by evaporation and reducing the nitrate ion content of an aqueous solution of metallic salts containing nitric acid not in excess of 8N. It consists of heating the solution and then passing formaldehyde into the heated solution to bring about decomposition of the nitric acid. The evolved gases containing NO are contacted countercurrently with an aqueous metal salt solution containing nitric acid in excess of 8N so as to bring about decomposition of the nitric acid and lower the normality to at least 8N, whereupon it is passed into the body of heated solution.

  11. Light-weight analyzer for odor recognition

    DOE Patents [OSTI]

    Vass, Arpad A; Wise, Marcus B

    2014-05-20

    The invention provides a light weight analyzer, e.g., detector, capable of locating clandestine graves. The detector utilizes the very specific and unique chemicals identified in the database of human decompositional odor. This detector, based on specific chemical compounds found relevant to human decomposition, is the next step forward in clandestine grave detection and will take the guess-work out of current methods using canines and ground-penetrating radar, which have historically been unreliable. The detector is self contained, portable and built for field use. Both visual and auditory cues are provided to the operator.

  12. Radiolysis Concerns for Water Shielding in Fission Surface Power Applications

    SciTech Connect (OSTI)

    Schoenfeld, Michael P.; Anghaie, Samim

    2008-01-21

    This paper presents an overview of radiolysis concerns with regard to water shields for fission surface power. A review of the radiolysis process is presented and key parameters and trends are identified. From this understanding of the radiolytic decomposition of water, shield pressurization and corrosion are identified as the primary concerns. Existing experimental and modeling data addressing concerns are summarized. It was found that radiolysis of pure water in a closed volume results in minimal, if any net decomposition, and therefore reduces the potential for shield pressurization and corrosion.

  13. Alpha and gamma radioysis of nuclear solvent etxraction ligands used for An(III) and Ln(III) Separations

    SciTech Connect (OSTI)

    Stephen P. Mezyk; Bruce J. Mincher; Christian Ekberg; Gunnar Skarnemark

    2013-05-01

    The separation of the minor actinides from dissolved nuclear fuel remains a major challenge in developing large-scale waste separations processes. One important criterion is that all these processes must be robust under high acidity and radiation dose conditions. Here we have investigated the TRUEX ligand CMPO in dodecane, comparing the effects of gamma (60Co) with alpha irradiation using isotopic alpha sources (244Cm, 211At) experiments. The radiolytically-based CMPO decomposition efficiencies are approximately the same for both types of radiolysis, with the overall decomposition being significantly less when this formulation is irradiated in contact with aqueous acid.

  14. Parallel Computation of Persistent Homology using the Blowup Complex

    SciTech Connect (OSTI)

    Lewis, Ryan; Morozov, Dmitriy

    2015-04-27

    We describe a parallel algorithm that computes persistent homology, an algebraic descriptor of a filtered topological space. Our algorithm is distinguished by operating on a spatial decomposition of the domain, as opposed to a decomposition with respect to the filtration. We rely on a classical construction, called the Mayer--Vietoris blowup complex, to glue global topological information about a space from its disjoint subsets. We introduce an efficient algorithm to perform this gluing operation, which may be of independent interest, and describe how to process the domain hierarchically. We report on a set of experiments that help assess the strengths and identify the limitations of our method.

  15. C%2B%2B tensor toolbox user manual.

    SciTech Connect (OSTI)

    Plantenga, Todd D.; Kolda, Tamara Gibson

    2012-04-01

    The C++ Tensor Toolbox is a software package for computing tensor decompositions. It is based on the Matlab Tensor Toolbox, and is particularly optimized for sparse data sets. This user manual briefly overviews tensor decomposition mathematics, software capabilities, and installation of the package. Tensors (also known as multidimensional arrays or N-way arrays) are used in a variety of applications ranging from chemometrics to network analysis. The Tensor Toolbox provides classes for manipulating dense, sparse, and structured tensors in C++. The Toolbox compiles into libraries and is intended for use with custom applications written by users.

  16. The FBI wavelet/scalar quantization standard for gray-scale fingerprint image compression

    SciTech Connect (OSTI)

    Bradley, J.N.; Brislawn, C.M. ); Hopper, T. )

    1993-01-01

    The FBI has recently adopted a standard for the compression of digitized 8-bit gray-scale fingerprint images. The standard is based on scalar quantization of a 64-subband discrete wavelet transform decomposition of the images, followed by Huffman coding. Novel features of the algorithm include the use of symmetric boundary conditions for transforming finite-length signals and a subband decomposition tailored for fingerprint images scanned at 500 dpi. The standard is intended for use in conjunction with ANSI/NBS-CLS 1-1993, American National Standard Data Format for the Interchange of Fingerprint Information, and the FBI's Integrated Automated Fingerprint Identification System.

  17. The FBI wavelet/scalar quantization standard for gray-scale fingerprint image compression

    SciTech Connect (OSTI)

    Bradley, J.N.; Brislawn, C.M.; Hopper, T.

    1993-05-01

    The FBI has recently adopted a standard for the compression of digitized 8-bit gray-scale fingerprint images. The standard is based on scalar quantization of a 64-subband discrete wavelet transform decomposition of the images, followed by Huffman coding. Novel features of the algorithm include the use of symmetric boundary conditions for transforming finite-length signals and a subband decomposition tailored for fingerprint images scanned at 500 dpi. The standard is intended for use in conjunction with ANSI/NBS-CLS 1-1993, American National Standard Data Format for the Interchange of Fingerprint Information, and the FBI`s Integrated Automated Fingerprint Identification System.

  18. Dispersion toughened ceramic composites and method for making same

    DOE Patents [OSTI]

    Stinton, D.P.; Lackey, W.J.; Lauf, R.J.

    1984-09-28

    Ceramic composites exhibiting increased fracture toughness are produced by the simultaneous codeposition of silicon carbide and titanium disilicide by chemical vapor deposition. A mixture of hydrogen, methyltrichlorosilane and titanium tetrachloride is introduced into a furnace containing a substrate such as graphite or silicon carbide. The thermal decomposition of the methyltrichlorosilane provides a silicon carbide matrix phase and the decomposition of the titanium tetrachloride provides a uniformly dispersed second phase of the intermetallic titanium disilicide within the matrix phase. The fracture toughness of the ceramic composite is in the range of about 6.5 to 7.0 MPa..sqrt..m which represents a significant increase over that of silicon carbide.

  19. Dispersion toughened ceramic composites and method for making same

    DOE Patents [OSTI]

    Stinton, David P.; Lackey, Walter J.; Lauf, Robert J.

    1986-01-01

    Ceramic composites exhibiting increased fracture toughness are produced by the simultaneous codeposition of silicon carbide and titanium disilicide by chemical vapor deposition. A mixture of hydrogen, methyltrichlorosilane and titanium tetrachloride is introduced into a furnace containing a substrate such as graphite or silicon carbide. The thermal decomposition of the methyltrichlorosilane provides a silicon carbide matrix phase and the decomposition of the titanium tetrachloride provides a uniformly dispersed second phase of the intermetallic titanium disilicide within the matrix phase. The fracture toughness of the ceramic composite is in the range of about 6.5 to 7.0 MPa.sqroot.m which represents a significant increase over that of silicon carbide.

  20. Antifoam degradation testing

    SciTech Connect (OSTI)

    Lambert, D. P.; Zamecnik, J. R.; Newell, D. D.; Williams, M. S.

    2015-08-20

    This report describes the results of testing to quantify the degradation products resulting from the dilution and storage of Antifoam 747. Antifoam degradation is of concern to the Defense Waste Processing Facility (DWPF) due to flammable decomposition products in the vapor phase of the Chemical Process Cell vessels, as well as the collection of flammable and organic species in the offgas condensate. The discovery that hexamethyldisiloxane is formed from the antifoam decomposition was the basis for a Potential Inadequacy in the Safety Analysis declaration by the DWPF.

  1. Potential role of the Fast Flux Test Facility and the advanced test reactor in the U.S. tritium production system

    SciTech Connect (OSTI)

    Dautel, W.A.

    1996-10-01

    The Deparunent of Energy is currently engaged in a dual-track strategy to develop an accelerator and a conunercial light water reactor (CLWR) as potential sources of tritium supply. New analysis of the production capabilities of the Fast Flux Test Facility (FFTF) at the Hanford Site argues for considering its inclusion in the tritium supply,system. The use of the FFTF (alone or together with the Advanced Test Reactor [ATR] at the Idaho National Engineering Laboratory) as an integral part of,a tritium production system would help (1) ensure supply by 2005, (2) provide additional time to resolve institutional and technical issues associated with the- dual-track strategy, and (3) reduce discounted total life-cycle`costs and near-tenn annual expenditures for accelerator-based systems. The FFRF would also provide a way to get an early start.on dispositioning surplus weapons-usable plutonium as well as provide a source of medical isotopes. Challenges Associated With the Dual-Track Strategy The Departinent`s purchase of either a commercial reactor or reactor irradiation services faces challenging institutional issues associated with converting civilian reactors to defense uses. In addition, while the technical capabilities of the individual components of the accelerator have been proven, the entire system needs to be demonstrated and scaled upward to ensure that the components work toge ther 1548 as a complete production system. These challenges create uncertainty over the ability of the du2a-track strategy to provide an assured tritium supply source by 2005. Because the earliest the accelerator could come on line is 2007, it would have to operate at maximum capacity for the first few years to regenerate the reserves lost through radioactive decay aftei 2005.

  2. Accelerating Computation of the Unit Commitment Problem (Presentation)

    SciTech Connect (OSTI)

    Hummon, M.; Barrows, C.; Jones, W.

    2013-10-01

    Production cost models (PCMs) simulate power system operation at hourly (or higher) resolution. While computation times often extend into multiple days, the sequential nature of PCM's makes parallelism difficult. We exploit the persistence of unit commitment decisions to select partition boundaries for simulation horizon decomposition and parallel computation. Partitioned simulations are benchmarked against sequential solutions for optimality and computation time.

  3. TiO2 nanotube arrays grown in ionic liquids: high-efficiency in photocatalysis and pore-widening

    SciTech Connect (OSTI)

    Li, Huaqing; Qu, Jun; Cui, Qingzhou; Xu, Hanbing; Luo, Huimin; Chi, Miaofang; Meisner, Roberta Ann; Wang, Wei; Dai, Sheng

    2011-01-01

    Debris-free, long, well-separated TiO2 nanotube arrays were obtained using an ionic liquid (IL) as electrolyte. The high conductivity of IL resulted in fast pore widening and few contaminants from electrolyte decomposition leading to high photocatalytic efficiency in water splitting.

  4. Degradation chemistry of PETN and its homologues

    SciTech Connect (OSTI)

    Shepodd, T.; Behrens, R.; Anex, D.; Miller, D.; Anderson, K.

    1997-11-01

    Pentaerythritol tetranitrate (PETN) is used throughout the stockpile as an energetic material. The formulation of PETN into XTX8003 (80% PETN, 20% Sylgard 182) creates an extrudable energetic composite. PETN and XTX8003 are used in the firesets for the retired W68 (MC2370) and the W76 (MC3028). When faced with potential lifetime extensions, energetic materials are naturally suspect regarding their output after prolonged aging. The authors have studied PETN and XTX8003 by looking at 25-year-old samples from retired MC2370s and newer materials. Both the old and new materials have also been placed in various accelerated aging protocols to investigate any decomposition that might occur over time. PETN is known to decompose autocatalytically even in the early stages of decomposition, but the process is poorly understood. Published values for the activation energy of decomposition vary by >40 kcal/mol. The 12 million year half life predicted for room temperature PETN would be dramatically shortened by chemical influences that lead to lower energy decomposition pathways. Degree of confinement, purity, and crystal size all influence degradation rates. In this paper, the authors observe the effects of chemical and thermal aging on PETN. They anticipate changes in mechanism at higher temperature aging, and before trying to extrapolate to lower temperatures, they want to make sure that they understand the different chemical processed involved.

  5. Evaluation of global horizontal irradiance to plane-of-array irradiance models at locations across the United States

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

    Lave, Matthew; Hayes, William; Pohl, Andrew; Hansen, Clifford W.

    2015-02-02

    We report an evaluation of the accuracy of combinations of models that estimate plane-of-array (POA) irradiance from measured global horizontal irradiance (GHI). This estimation involves two steps: 1) decomposition of GHI into direct and diffuse horizontal components and 2) transposition of direct and diffuse horizontal irradiance (DHI) to POA irradiance. Measured GHI and coincident measured POA irradiance from a variety of climates within the United States were used to evaluate combinations of decomposition and transposition models. A few locations also had DHI measurements, allowing for decoupled analysis of either the decomposition or the transposition models alone. Results suggest that decompositionmore » models had mean bias differences (modeled versus measured) that vary with climate. Transposition model mean bias differences depended more on the model than the location. Lastly, when only GHI measurements were available and combinations of decomposition and transposition models were considered, the smallest mean bias differences were typically found for combinations which included the Hay/Davies transposition model.« less

  6. Polychlorinated biphenyls: Occurrence in sediments and soils. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1993-02-01

    The bibliography contains citations concerning field and laboratory analyses of polychlorinated biphenyls (PCBs) in sediments and soils. Topics include site studies; chemical analyses of adsorption-desorption processes; decomposition in soils, including biodegradation; and bioaccumulation. Detection methods and instrumention, and the impact of dredging in contaminated areas are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  7. Polychlorinated biphenyls: Occurrence in sediments and soils. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1993-11-01

    The bibliography contains citations concerning field and laboratory analyses of polychlorinated biphenyls (PCBs) in sediments and soils. Topics include site studies; chemical analyses of adsorption-desorption processes; decomposition in soils, including biodegradation; and bioaccumulation. Detection methods and instrumention, and the impact of dredging in contaminated areas are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  8. Polychlorinated biphenyls: Occurrence in sediments and soils. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect (OSTI)

    Not Available

    1994-08-01

    The bibliography contains citations concerning field and laboratory analyses of polychlorinated biphenyls (PCBs) in sediments and soils. Topics include site studies; chemical analyses of adsorption-desorption processes; decomposition in soils, including biodegradation; and bioaccumulation. Detection methods and instrumention, and the impact of dredging in contaminated areas are also discussed. (Contains 250 citations and includes a subject term index and title list.)

  9. Analysis of thermally-degrading, confined HMX

    SciTech Connect (OSTI)

    Hobbs, M.L.; Schmitt, R.G.; Renlund, A.M.

    1996-12-01

    The response of a thermally-degrading, confined HMX pellet is analyzed using a Reactive Elastic-Plastic (REP) constitutive model which is founded on the collapse and growth of internal inclusions resulting from physical and chemical processes such as forced displacement, thermal expansion, and/or decomposition. Axial stress predictions compare adequately to data. Deficiencies in the model and future directions are discussed.

  10. Method of deposition of silicon carbide layers on substrates

    DOE Patents [OSTI]

    Angelini, P.; DeVore, C.E.; Lackey, W.J.; Blanco, R.E.; Stinton, D.P.

    1982-03-19

    A method for direct chemical vapor deposition of silicon carbide to substrates, especially nuclear waste particles, is provided by the thermal decomposition of methylsilane at 800 to 1050/sup 0/C when the substrates have been confined within a suitable coating environment.

  11. Method of deposition of silicon carbide layers on substrates and product

    DOE Patents [OSTI]

    Angelini, Peter; DeVore, Charles E.; Lackey, Walter J.; Blanco, Raymond E.; Stinton, David P.

    1984-01-01

    A method for direct chemical vapor deposition of silicon carbide to substrates, especially nuclear waste particles, is provided by the thermal decomposition of methylsilane at about 800.degree. C. to 1050.degree. C. when the substrates have been confined within a suitable coating environment.

  12. No reduction using sublimation of cyanuric acid

    DOE Patents [OSTI]

    Perry, Robert A.

    1990-01-01

    An arrangement for reducing the NO content of a gas stream comprises contacting the gas stream with NHCO into a temperature effective for heat induced decomposition of HNCO and for resultant lowering of the NO content of the gas stream. Preferably, the HNCO is generated by sublimation of cyanuric acid.

  13. Hydrogen-permeable composite metal membrane and uses thereof

    DOE Patents [OSTI]

    Edlund, David J.; Friesen, Dwayne T.

    1993-06-08

    Various hydrogen production and hydrogen sulfide decomposition processes are disclosed that utilize composite metal membranes that contain an intermetallic diffusion barrier separating a hydrogen-permeable base metal and a hydrogen-permeable coating metal. The barrier is a thermally stable inorganic proton conductor.

  14. Method and apparatus for pyrolysis of atactic polypropylene

    DOE Patents [OSTI]

    Staffin, H.K.; Roaper, R.B.

    1986-09-23

    This invention relates to an apparatus and a method for pyrolytic decomposition of polymeric materials into lower molecular weight products involving the heat treatment of raw polymeric material within reactive conduits submerged in a fluidized bed furnace operated at pyrolyzing temperatures. 1 fig.

  15. Competitive ion kinetics in direct mass spectrometric organic speciation: (Progress report, FY87-89)

    SciTech Connect (OSTI)

    Sieck, L.W.

    1987-01-01

    The following were studied: Stabilities of S...H/sup +/...X bonds, thermal decomposition of ions, stabilities of nitro anion association ions, stabilities of SF/sub 6//sup -/ association ions, proton affinities and cationic stabilization of tetraalkylhydrazines, adduct ion diagnostics in MS/MS, and anionic association ions incorporating RO/sup -/ or RCO/sub 2//sup -/.

  16. NO reduction using sublimation of cyanuric acid

    DOE Patents [OSTI]

    Perry, Robert A.

    1988-01-01

    An arrangement for reducing the NO content of a gas stream comprises contacting the gas stream with HNCO at a temperature effective for heat induced decomposition of HNCO and for resultant lowering of the NO content of the gas stream. Preferably, the HNCO is generated by sublimation of cyanuric acid.

  17. System for NO reduction using sublimation of cyanuric acid

    DOE Patents [OSTI]

    Perry, Robert A.

    1989-01-01

    An arrangement for reducing the NO content of a gas stream comprises contacting the gas stream with HNCO at a temperature effective for heat induced decomposition of HNCO and for resultant lowering of the NO content of the gas stream. Preferably, the HNCO is generated by sublimation of cyanuric acid.

  18. System for NO reduction using sublimation of cyanuric acid

    DOE Patents [OSTI]

    Perry, R.A.

    1989-01-24

    An arrangement for reducing the NO content of a gas stream comprises contacting the gas stream with HNCO at a temperature effective for heat induced decomposition of HNCO and for resultant lowering of the NO content of the gas stream. Preferably, the HNCO is generated by sublimation of cyanuric acid. 1 fig.

  19. Laminate articles on biaxially textured metal substrates (Patent...

    Office of Scientific and Technical Information (OSTI)

    The (RE.sup.1.sub.x RE.sup.2.sub.(1-x)).sub.2 O.sub.3 buffer layer can be deposited using sol-gel or metal-organic decomposition. The laminate article can include a layer of YBCO ...

  20. Apparatus for upgrading heavy hydrocarbons employing a diluent

    SciTech Connect (OSTI)

    Calderon, J. L.; Layrisse, I.

    1985-06-04

    Apparatus for upgrading heavy hydrocarbonaceous materials for making coke suitable for metallurgical purposes comprises mixing the heavy hydrocarbonaceous materials with a diluent having a closely controlled boiling range so as to facilitate transport, dehydration and desalting of the crude oil. In addition, the diluent aids in controlling temperature and residence time of the crude thereby avoiding premature decomposition.