Sample records for homogeneous catalysis heterogeneous

  1. Converting Homogeneous to Heterogeneous in Electrophilic Catalysis using Monodisperse Metal Nanoparticles

    SciTech Connect (OSTI)

    Witham, Cole A.; Huang, Wenyu; Tsung, Chia-Kuang; Kuhn, John N.; Somorjai, Gabor A.; Toste, F. Dean

    2009-10-15T23:59:59.000Z

    A continuing goal in catalysis is the transformation of processes from homogeneous to heterogeneous. To this end, nanoparticles represent a new frontier in heterogeneous catalysis, where this conversion is supplemented by the ability to obtain new or divergent reactivity and selectivity. We report a novel method for applying heterogeneous catalysts to known homogeneous catalytic reactions through the design and synthesis of electrophilic platinum nanoparticles. These nanoparticles are selectively oxidized by the hypervalent iodine species PhICl{sub 2}, and catalyze a range of {pi}-bond activation reactions previously only homogeneously catalyzed. Multiple experimental methods are utilized to unambiguously verify the heterogeneity of the catalytic process. The discovery of treatments for nanoparticles that induce the desired homogeneous catalytic activity should lead to the further development of reactions previously inaccessible in heterogeneous catalysis. Furthermore, our size and capping agent study revealed that Pt PAMAM dendrimer-capped nanoparticles demonstrate superior activity and recyclability compared to larger, polymer-capped analogues.

  2. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    K. Lee Semiconductor Photocatalysis in Advanced Oxidationthermal) catalysis or photocatalysis on nanoporous supportswith Heterogeneous Photocatalysis using Nanostructured

  3. ISHHC XIII International Symposium on the Relations betweenHomogeneous and Heterogeneous Catalysis

    SciTech Connect (OSTI)

    Somorjai (Ed.), G.A.

    2007-06-11T23:59:59.000Z

    The International Symposium on Relations between Homogeneous and Heterogeneous Catalysis (ISHHC) has a long and distinguished history. Since 1974, in Brussels, this event has been held in Lyon, France (1977), Groeningen, The Netherlands (1981); Asilomar, California (1983); Novosibirsk, Russia (1986); Pisa, Italy (1989); Tokyo, Japan (1992); Balatonfuered, Hungary (1995); Southampton, United Kingdom (1999); Lyon, France (2001); Evanston, Illinois (2001) and Florence, Italy (2005). The aim of this international conference in Berkeley is to bring together practitioners in the three fields of catalysis, heterogeneous, homogeneous and enzyme, which utilize mostly nanosize particles. Recent advances in instrumentation, synthesis and reaction studies permit the nanoscale characterization of the catalyst systems, often for the same reaction, under similar experimental conditions. It is hoped that this circumstance will permit the development of correlations of these three different fields of catalysis on the molecular level. To further this goal we aim to uncover and focus on common concepts that emerge from nanoscale studies of structures and dynamics of the three types of catalysts. Another area of focus that will be addressed is the impact on and correlation of nanosciences with catalysis. There is information on the electronic and atomic structures of nanoparticles and their dynamics that should have importance in catalyst design and catalytic activity and selectivity.

  4. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    Catalytic Processes Applied Catalysis A: General 221 (2001)Kamp, J.J.F. Scholten Applied Catalysis A. : General 89 (77. S. Xie, M. Qiao Applied Catalysis A: General 176 (1999)

  5. Heterogeneous Catalysis Environmental Catalysis and Processes

    E-Print Network [OSTI]

    Vardi, Amichay

    Department of Chemical Engineering Ben ­ Gurion University of the Negev Blechner Center for Applied CatalysisHeterogeneous Catalysis Environmental Catalysis and Processes Renewable Fuels M. Herskowitz Nanotechnology and advanced methods are applied in use inspired research #12;Fundamental research of catalytic

  6. Heterogeneous Catalysis on Atomically Dispersed Supported Metals...

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

    Catalysis on Atomically Dispersed Supported Metals: CO2 Reduction on Multifunctional Pd Catalysts. Heterogeneous Catalysis on Atomically Dispersed Supported Metals: CO2 Reduction...

  7. Is It Homogeneous or Heterogeneous Catalysis Derived from [RhCp*Cl2]2? In Operando-XAFS, Kinetic and Crucial Kinetic Poisoning Evidence for Subnanometer Rh4 Cluster-Based Benzene Hydrogenation Catalysis

    SciTech Connect (OSTI)

    Bayram, Ercan; Linehan, John C.; Fulton, John L.; Roberts, John A.; Szymczak, Nathaniel; Smurthwaite, Tricia D.; Ozkar, Saim; Balasubramanian, Mahalingam; Finke, Richard G.

    2011-11-23T23:59:59.000Z

    Determining the true, kinetically dominant catalytically active species, in the classic benzene hydrogenation system pioneered by Maitlis and co-workers 34 years ago starting with [RhCp*Cl2]2 (Cp* = [{eta}5-C5(CH3)5]), has proven to be one of the most challenging case studies in the quest to distinguish single-metal-based 'homogeneous' from polymetallic, 'heterogeneous' catalysis. The reason, this study will show, is the previous failure to use the proper combination of (i) operando spectroscopy to determine the dominant form(s) of the precatalyst's mass under catalysis (i.e., operating) conditions, plus then and crucially also (ii) the previous lack of the necessary kinetic studies, catalysis being a 'wholly kinetic phenomenon' as J. Halpern long ago noted. An important contribution from this study will be to reveal the power of quantitiative kinetic poisoning experiments for distinguishing single-metal, or in this case subnanometer Rh4 cluster-based catalysis from larger, polymetallic Rh(0)n nanoparticle catalysis, at least under favorable conditions. The combined operando-XAFS (X-ray absorption fine structure) spectroscopy and kinetic evidences provide a compelling case for Rh4-based, with average stoichiometry 'Rh4Cp*2.4Cl4Hc', benzene hydrogenation catalysis in 2-propanol with added Et3N and at 100 C and 50 atm initial H2 pressure. The results also reveal, however, that if even ca. 1.4% of the total soluble Rh(0)n had formed nanoparticles, then those Rh(0)n nanoparticles would have been able to account for all the observed benzene hydrogenation catalytic rate (using commercial, ca. 2 nm, polyethyleneglycol-dodecylether hydrosol stabilized Rh(0)n nanoparticles as a model system). The results 'especially the poisoning methodology developed and employed' are of significant, broader interest since determining the nature of the true catalyst continues to be a central, often vexing issue in any and all catalytic reactions. The results are also of fundamental interest in that they add to a growing body of evidence indicating that certain, appropriately ligated, coordinatively unsaturated, subnanometer M4 transition-metal clusters can be relatively robust catalysts. Also demonstrated herein is that Rh4 clusters are poisoned by Hg(0), demonstrating for the first time that the classic Hg(0) poisoning test of 'homogeneous' vs 'heterogeneous'catalysts cannot distinguish Rh4-based subnanometer catalysts from Rh(0)n nanoparticle catalysts, at least for the present examples of these two specific, Rh-based catalysts.

  8. ISOTOPE METHODS IN HOMOGENEOUS CATALYSIS.

    SciTech Connect (OSTI)

    BULLOCK,R.M.; BENDER,B.R.

    2000-12-01T23:59:59.000Z

    The use of isotope labels has had a fundamentally important role in the determination of mechanisms of homogeneously catalyzed reactions. Mechanistic data is valuable since it can assist in the design and rational improvement of homogeneous catalysts. There are several ways to use isotopes in mechanistic chemistry. Isotopes can be introduced into controlled experiments and followed where they go or don't go; in this way, Libby, Calvin, Taube and others used isotopes to elucidate mechanistic pathways for very different, yet important chemistries. Another important isotope method is the study of kinetic isotope effects (KIEs) and equilibrium isotope effect (EIEs). Here the mere observation of where a label winds up is no longer enough - what matters is how much slower (or faster) a labeled molecule reacts than the unlabeled material. The most careti studies essentially involve the measurement of isotope fractionation between a reference ground state and the transition state. Thus kinetic isotope effects provide unique data unavailable from other methods, since information about the transition state of a reaction is obtained. Because getting an experimental glimpse of transition states is really tantamount to understanding catalysis, kinetic isotope effects are very powerful.

  9. Catalysis of Protein Disulfide Bond Isomerization in a Homogeneous Substrate Elizabeth A. Kersteen,, Seth R. Barrows, and Ronald T. Raines*,,|

    E-Print Network [OSTI]

    Raines, Ronald T.

    Catalysis of Protein Disulfide Bond Isomerization in a Homogeneous Substrate Elizabeth A. Kersteen in these assays are, however, heterogeneous, which complicates mechanistic analyses. Here, we report the first use this continuous assay to analyze catalysis by wild-type human PDI and a variant in which the C

  10. Periodic Solutions of a Nonlinear Evolution Problem from Heterogeneous Catalysis

    E-Print Network [OSTI]

    Bothe, Dieter

    Periodic Solutions of a Nonlinear Evolution Problem from Heterogeneous Catalysis Dieter Bothe for heterogeneous catalysis in a stirred multi-phase chemical reactor. Since the appearance of T-periodic feeds for this evolution problem are provided and applied to the class of reaction-diffusion systems mentioned above. AMS

  11. Heterogeneous Catalysis DOI: 10.1002/anie.201209476

    E-Print Network [OSTI]

    Kik, Pieter

    Heterogeneous Catalysis DOI: 10.1002/anie.201209476 Trends in the Binding Strength of Surface? These questions are at the heart of many fundamental and practical problems, ranging from heterogeneous catalysis to important applied processes con- nected to materials science. In particular the interaction of oxygen

  12. Homogeneous Catalysis Selective Oxidation of Methane to Methanol

    E-Print Network [OSTI]

    Goddard III, William A.

    Homogeneous Catalysis Selective Oxidation of Methane to Methanol Catalyzed, with CÀH Activation (generated by dissolution[6] of Au2O3) react with methane at 1808C to selectively generate methanol (as a mixture of the ester and methanol) in high yield (Table 1, entries 1 and 2). As expected, the irreversible

  13. Molecular-Level Design of Heterogeneous Chiral Catalysis

    SciTech Connect (OSTI)

    Francisco Zaera

    2012-03-21T23:59:59.000Z

    The following is a proposal to continue our multi-institutional research on heterogeneous chiral catalysis. Our team combines the use of surface-sensitive analytical techniques for the characterization of model systems with quantum and statistical mechanical calculations to interpret experimental data and guide the design of future research. Our investigation focuses on the interrelation among the three main mechanisms by which enantioselectivity can be bestowed to heterogeneous catalysts, namely: (1) by templating chirality via the adsorption of chiral supramolecular assemblies, (2) by using chiral modifiers capable of forming chiral complexes with the reactant and force enantioselective surface reactions, and (3) by forming naturally chiral surfaces using imprinting chiral agents. Individually, the members of our team are leaders in these various aspects of chiral catalysis, but the present program provides the vehicle to generate and exploit the synergies necessary to address the problem in a comprehensive manner. Our initial work has advanced the methodology needed for these studies, including an enantioselective titration procedure to identify surface chiral sites, infrared spectroscopy in situ at the interface between gases or liquids and solids to mimic realistic catalytic conditions, and DFT and Monte Carlo algorithms to simulate and understand chirality on surfaces. The next step, to be funded by the monies requested in this proposal, is to apply those methods to specific problems in chiral catalysis, including the identification of the requirements for the formation of supramolecular surface structures with enantioselective behavior, the search for better molecules to probe the chiral nature of the modified surfaces, the exploration of the transition from supramolecular to one-to-one chiral modification, the correlation of the adsorption characteristics of one-to-one chiral modifiers with their physical properties, in particular with their configuration, and the development of ways to imprint chiral centers on achiral solid surfaces. Chiral catalysis is not only a problem of great importance in its own right, but also the ultimate test of how to control selectivity in catalysis. The time is ripe for fundamental work in heterogeneous chiral catalysis to provide the U.S. with a leadership role in developing the next generation of catalytic processes for medicinal and agrochemical manufacturing. Our team provides the required expertise for a synergistic and comprehensive integration of physical and chemical experimentation with solid state and molecular reactivity theories to solve this problem.

  14. Charge Transfer and Support Effects in Heterogeneous Catalysis

    E-Print Network [OSTI]

    Hervier, Antoine

    2012-01-01T23:59:59.000Z

    T. ; Haruta, M.  Applied Catalysis A:  General 1998, 169, Albert Vannice, M.  Applied Catalysis A: General 1994, 113, Viswanath, R.  P.  Applied Catalysis A: General 2001, 208, 

  15. Transformation of Sorbitol to Biofuels by Heterogeneous Catalysis: Chemical and Industrial

    E-Print Network [OSTI]

    Boyer, Edmond

    Transformation of Sorbitol to Biofuels by Heterogeneous Catalysis: Chemical and Industrial ainsi que des exemples d'applications industrielles. Abstract -- Transformation of Sorbitol to Biofuels and biodiesel production led to first generation biofuels. Nowadays, research is focused on lignocellulosic

  16. Percolation and homogenization theories for heterogeneous materials

    E-Print Network [OSTI]

    Chen, Ying, Ph. D. Massachusetts Institute of Technology

    2008-01-01T23:59:59.000Z

    Most materials produced by Nature and by human beings are heterogeneous. They contain domains of different states, structures, compositions, or material phases. How these different domains are distributed in space, or in ...

  17. HOMOGENEOUS CATALYSIS AND MASS TRANSFER IN BIPHASIC IONIC LIQUID SYSTEMS WITH COMPRESSED CO2 AND ORGANIC COMPOUNDS

    E-Print Network [OSTI]

    Ahosseini, Azita

    ABSTRACT Homogeneous catalysis in which the catalyst, solvents and reactants are all in the same phase can yield high activity and selectivity and efficiently produce chemical products. However, the main problem with these ...

  18. Cryogenic homogenization and sampling of heterogeneous multi-phase feedstock

    DOE Patents [OSTI]

    Doyle, Glenn Michael (Lakewood, CO); Ideker, Virgene Linda (Arvada, CO); Siegwarth, James David (Boulder, CO)

    2002-01-01T23:59:59.000Z

    An apparatus and process for producing a homogeneous analytical sample from a heterogenous feedstock by: providing the mixed feedstock, reducing the temperature of the feedstock to a temperature below a critical temperature, reducing the size of the feedstock components, blending the reduced size feedstock to form a homogeneous mixture; and obtaining a representative sample of the homogeneous mixture. The size reduction and blending steps are performed at temperatures below the critical temperature in order to retain organic compounds in the form of solvents, oils, or liquids that may be adsorbed onto or absorbed into the solid components of the mixture, while also improving the efficiency of the size reduction. Preferably, the critical temperature is less than 77 K (-196.degree. C.). Further, with the process of this invention the representative sample may be maintained below the critical temperature until being analyzed.

  19. DOE Laboratory Catalysis Research Symposium - Abstracts

    SciTech Connect (OSTI)

    Dunham, T.

    1999-02-01T23:59:59.000Z

    The conference consisted of two sessions with the following subtopics: (1) Heterogeneous Session: Novel Catalytic Materials; Photocatalysis; Novel Processing Conditions; Metals and Sulfides; Nuclear Magnetic Resonance; Metal Oxides and Partial Oxidation; Electrocatalysis; and Automotive Catalysis. (2) Homogeneous Catalysis: H-Transfer and Alkane Functionalization; Biocatalysis; Oxidation and Photocatalysis; and Novel Medical, Methods, and Catalyzed Reactions.

  20. Journal of Catalysis 191, 4654 (2000) doi:10.1006/jcat.1999.2798, available online at http://www.idealibrary.com on

    E-Print Network [OSTI]

    Androulakis, Ioannis (Yannis)

    2000-01-01T23:59:59.000Z

    high-temperature processes based on heterogeneous catalysis may involve homogeneous gas-phase reactionsJournal of Catalysis 191, 46­54 (2000) doi:10.1006/jcat.1999.2798, available online at http

  1. Charge Transfer and Support Effects in Heterogeneous Catalysis

    SciTech Connect (OSTI)

    Hervier, Antoine

    2011-12-21T23:59:59.000Z

    The kinetic, electronic and spectroscopic properties of two?dimensional oxide?supported catalysts were investigated in order to understand the role of charge transfer in catalysis. Pt/TiO{sub 2} nanodiodes were fabricated and used as catalysts for hydrogen oxidation. During the reaction, the current through the diode, as well as its I?V curve, were monitored, while gas chromatography was used to measure the reaction rate. The current and the turnover rate were found to have the same temperature dependence, indicating that hydrogen oxidation leads to the non?adiabatic excitation of electrons in Pt. A fraction of these electrons have enough energy to ballistically transport through Pt and overcome the Schottky barrier at the interface with TiO{sub 2}. The yield for this phenomenon is on the order of 10{sup ?4} electrons per product molecule formed, similar to what has been observed for CO oxidation and for the adsorption of many different molecules. The same Pt/TiO{sub 2} system was used to compare currents in hydrogen oxidation and deuterium oxidation. The current through the diode under deuterium oxidation was found to be greater than under hydrogen oxidation by a factor of three. Weighted by the difference in turnover frequencies for the two isotopes, this would imply a chemicurrent yield 5 times greater for D{sub 2} compared to H{sub 2}, contrary to what is expected given the higher mass of D{sub 2}. Reversible changes in the rectification factor of the diode are observed when switching between D{sub 2} and H{sub 2}. These changes are a likely cause for the differences in current between the two isotopes. In the nanodiode experiments, surface chemistry leads to charge flow, suggesting the possibility of creating charge flow to tune surface chemistry. This was done first by exposing a Pt/Si diode to visible light while using it as a catalyst for H{sub 2} oxidation. Absorption of the light in the Si, combined with the band bending at the interface, gives rise to a steady?state flow of hot holes to the surface. This leads to a decrease in turnover on the surface, an effect which is enhanced when a reverse bias is applied to the diode. Similar experiments were carried out for CO oxidation. On Pt/Si diodes, the reaction rate was found to increase when a forward bias was applied. When the diode was exposed to visible light and a reverse bias was applied, the rate was instead decreased. This implies that a flow of negative charges to the surface increases turnover, while positive charges decrease it. Charge flow in an oxide supported metal catalyst can be modified even without designing the catalyst as a solid state electronic device. This was done by doping stoichiometric and nonstoichiometric TiO{sub 2} films with F, and using the resulting oxides as supports for Pt films. In the case of stoichiometric TiO{sub 2}, F was found to act as an n?type dopant, creating a population of filled electronic states just below the conduction band, and dramatically increasing the conductivity of the oxide film. The electrons in those states can transfer to surface O, activating it for reaction with CO, and leading to increased turnover for CO oxidation. This reinforces the hypothesis that CO oxidation is activated by a flow of negative charges to the surface. The same set of catalysts was used for methanol oxidation. The electronic properties of the TiO{sub 2} films again correlated with the turnover rates, but also with selectivity. With stoichiometric TiO{sub 2} as the support, F?doping caused an increase in selectivity toward the formation of partial oxidation products, formaldehyde and methyl formate, versus the total oxidation product, CO{sub 2}. With non?stoichiometric TiO{sub 2}, F?doping had the reverse effect. Ambient Pressure X?Ray Photoelectron Spectroscopy was used to investigate this F?doping effect in reaction conditions. In O2 alone, and in CO oxidation conditions, the O1s spectrum showed a high binding energy peak that correlated in intensity with the activity of the different films: for stoichiomet

  2. Highly Dispersed Pseudo-Homogeneous and Heterogeneous Catalysts Synthesized via Inverse Micelle Solutions for the Liquefaction of Coal

    SciTech Connect (OSTI)

    Hampden-Smith, M.; Kawola, J.S.; Martino, A.; Sault, A.G.; Yamanaka, S.A.

    1999-01-05T23:59:59.000Z

    The mission of this project was to use inverse micelle solutions to synthesize nanometer sized metal particles and test the particles as catalysts in the liquefaction of coal and other related reactions. The initial focus of the project was the synthesis of iron based materials in pseudo-homogeneous form. The frost three chapters discuss the synthesis, characterization, and catalyst testing in coal liquefaction and model coal liquefaction reactions of iron based pseudo-homogeneous materials. Later, we became interested in highly dispersed catalysts for coprocessing of coal and plastic waste. Bifunctional catalysts . to hydrogenate the coal and depolymerize the plastic waste are ideal. We began studying, based on our previously devised synthesis strategies, the synthesis of heterogeneous catalysts with a bifunctional nature. In chapter 4, we discuss the fundamental principles in heterogeneous catalysis synthesis with inverse micelle solutions. In chapter 5, we extend the synthesis of chapter 4 to practical systems and use the materials in catalyst testing. Finally in chapter 6, we return to iron and coal liquefaction now studied with the heterogeneous catalysts.

  3. Bifurcation behavior in homogeneous-heterogeneous combustion. Part 2; Computations for stagnation-point flow

    SciTech Connect (OSTI)

    Song, X.; Williams, W.R.; Schmidt, L.D.; Aris, R. (Dept. of Chemical Engineering and Materials Science, Univ. of Minnesota, Minneapolis, MN (US))

    1991-04-01T23:59:59.000Z

    Bifurcation analysis of ignition and extinction of combustion in stagnation-point flow was carried out for conditions when both homogeneous and heterogeneous reactions can occur. A technique based on the bifurcation theory and the shooting algorithm is developed, which permits fast and efficient tracking of bifurcation in these systems. The influences of the different parameters on the ignition and extinction behavior were investigated by assuming (1) only catalytic surface (heterogeneous) reaction, (2) only homogeneous reaction on a hot inert surface, and (3) both surface and homogeneous reactions. The coupling effects of the homogeneous and heterogeneous reactions are clearly demonstrated. It is shown that the heterogeneous reaction dominates the system behavior at the lower temperature while both homogeneous and heterogeneous reactions play important role at higher temperature. It is predicted that the homogeneous ignition temperature is higher with surface reaction than without surface reaction. However, homogeneous-heterogeneous or homogeneous reaction alone. The numerical results for propane and for methane oxidation on platinum foil also show good qualitative agreements with the experimental results of Part I of this article, which include the two types of ignition, extinction and autothermal behavior of homogeneous-heterogeneous reactions.

  4. On the critical salt concentrations for particle detachment in homogeneous sand and heterogeneous Hanford sediments

    E-Print Network [OSTI]

    Selker, John

    On the critical salt concentrations for particle detachment in homogeneous sand and heterogeneous June 2004 Abstract One of the mechanisms for sudden particle release is a decrease in groundwater salt concentration to below the critical salt concentration (CSC), where repulsion forces between fine particles

  5. Analysis of the finite element heterogeneous multiscale method for nonlinear elliptic homogenization problems.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Analysis of the finite element heterogeneous multiscale method for nonlinear elliptic homogenization problems. Assyr Abdulle and Gilles Vilmart September 28, 2012 Abstract An analysis of the finite finite elements. Op- timal a-priori error estimates are obtained for the H1 and L2 norms, error bounds

  6. The performance of 3500 MWth homogeneous and heterogeneous metal fueled core designs

    SciTech Connect (OSTI)

    Turski, R.; Yang, Shi-tien

    1987-11-01T23:59:59.000Z

    Performance parameters are calculated for a representative 3500 MWth homogeneous and a heterogeneous metal fueled reactor design. The equilibrium cycle neutronic characteristics, safety coefficients, control system requirements, and control rod worths are evaluated. The thermal-hydraulic characteristics for both configurations are also compared. The heavy metal fuel loading requirements and neutronic performance characteristics are also evaluated for the uranium startup option. 14 refs., 14 figs., 20 tabs.

  7. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    Pelzer, K. Philippot, M. G´ mez, o G. Muller, P. Lecante, B.F. Malbosc, Y. Kihn, M. G´ mez Green Chemistry submitted. oPicurelli, A. Oliva, M. G´ mez, V. Branchadell, R.M. Ortu˜ o

  8. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    for Nanostructured Materials, University of Trieste, via A.Valerio 2, 34127, Trieste, Italy Laboratorio Nazionale TASC34012, Basovizza (Trieste), Italy Chemistry Department,

  9. Converting Homogeneous to Heterogeneous in Electrophilic Catalysis using Monodisperse Metal Nanoparticles

    E-Print Network [OSTI]

    Witham, Cole A.

    2011-01-01T23:59:59.000Z

    Synthesis of One Nanometer Rh and Pt Particles Supported on Mesoporous Silica: Catalytic Activity for Ethylene and Pyrrole

  10. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    Chemical Engineering Department, University of Pittsburgh, Pittsburgh, PA Department of Energy, National Energy Technology Laboratory, Pittsburgh, PA The design

  11. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    measurements. With an infrared laser, heating and coolingbeam for detection. Infrared laser heating is a successful

  12. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    size e?ect in the Fischer-Tropsch synthesis. ” Stud. Surf.E. Rytter, A. Holmen ”Fischer-Tropsch synthesis over ?-Al 2Rytter, A. Holmen ”Fischer-Tropsch synthesis on Co supported

  13. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    or sulfated zirconia (MOx) a?ords propene and supportedium(III) catalysts, (allyl) 2 Ir-O-MOx. These catalysts were

  14. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    due to low solubility of syngas remain a problem for e?cientof methane to form syngas. 2 However, the structure andin the production of syngas and hydrogen from fossil and

  15. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    Department of Chemical and Petroleum Engineering, UniversityDepartment of Chemical and Petroleum Engineering, University

  16. ISHHC XIII International Symposium on the Relations between Homogeneous and Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai Ed., G.A.

    2007-01-01T23:59:59.000Z

    led to outstanding catalysts, showing an excellent activity without leaching of metal up to ten recycling

  17. Asymmetric Catalysis at the Mesoscale: Gold Nanoclusters Embedded in Chiral Self-Assembled Monolayer as Heterogeneous

    E-Print Network [OSTI]

    Asymmetric Catalysis at the Mesoscale: Gold Nanoclusters Embedded in Chiral Self of the catalytically active metallic sites and the surrounding chiral SAM for the formation of a mesoscale the catalytically active site from the nanoscale to the mesoscale, which implies a principle of operating systems

  18. Bifurcation behavior in homogeneous-heterogeneous combustion. Part 1. ; Experimental results over platinum

    SciTech Connect (OSTI)

    Williams, W.R.; Stenzel, M.T.; Song, X.; Schmidt, L.D. (Dept. of Chemical Engineering and Materials Science, Univ. of Minnesota, Minneapolis, MN (US))

    1991-04-01T23:59:59.000Z

    Ignition, extinction, and autothermal behavior of the homogeneous and heterogeneous oxidation reactions in air of NH{sub 3}, CH{sub 4}, C{sub 3}H{sub 8}, and an equipolar NH{sub 3}/CH{sub 4} mixture over resistively heated polycrystalline platinum foils was studied in an atmospheric pressure flow reactor as a function of low rate, fuel concentration, preheat temperature, and reactor geometry. Surface temperature versus power curves were experimentally determined for different compositions in these systems, which were in turn summarized in bifurcation diagrams of surface temperature or power as a function of fuel composition. Two ignitions (heterogeneous and homogeneous), one extinction and one self-sustaining autothermal steady state, were observed for all systems except NH{sub 3}/CH{sub 4} oxidation. The heterogeneous ignition occurred around 600 {degrees} C for CH{sub 4} and 200 {degrees} C for all other systems and was weakly dependent on the fuel composition. Long transients due to carbon formation were observed in the autothermal behavior for fuel-rich compositions in the CH{sub 4} system. A second heterogeneous ignition occurred in NH{sub 3}/CH{sub 4} oxidation, which ranged from 400 {degrees} to 600 {degrees} C. Homogeneous reaction ignited at surface temperatures ranging from 1050 {degrees} C for C{sub 3}H{sub 8} oxidation to 1500 {degrees} C for CH{sub 4} and NH{sub 3} oxidation. For C{sub 3}H{sub 8} and CH{sub 4} oxidation, the flame generally left the foil, but in NH {sub 3} oxidation a stable boundary layer flame was also observed under some conditions.

  19. A microreactor system for high-pressure, multiphase homogeneous and heterogeneous catalyst measurements under continuous flow

    E-Print Network [OSTI]

    Keybl, Jaroslav

    2011-01-01T23:59:59.000Z

    The shift towards biomass and lower quality fossil fuel feedstocks will require new conversion approaches. Catalysis will be critical in the processing of these new feedstocks. By studying catalysis at industrially relevant ...

  20. In-situ study of the chemically driven flow fields in initiating homogeneous and heterogeneous nitromethane explosives

    SciTech Connect (OSTI)

    Sheffield, S.A.; Engelke, R.; Alcon, R.R.

    1989-01-01T23:59:59.000Z

    Electromagnetic gauging has been used to make in-situ measurements of particle velocity and impulse at five Lagrangian positions in nitromethane (NM) during gas-gun-driven, shock-to-detonation experiments. Homogeneous initiation experiments were conducted using NM that was chemically sensitized (using an organic base) and heterogeneous initiation experiments were done with physically sensitized NM (using silica particles). In the homogeneous initiation experiments, some of the features we observed are consistent with the classical homogeneous initiation model, however, our measurements show that the superdetonation does not form immediately after an induction time. Considerably behind the initial shock, reaction causes a wave to build up over a discernible length and this wave evolves into a superdetonation which catches the initial shock. In the heterogeneous initiation experiments, the waveforms indicated that wave growth occurs primarily in the shock front, similar to earlier observations in other heterogeneous explosives. 21 refs., 8 figs., 3 tabs.

  1. Metal complexes with bifunctional imidazolyl phosphines for catalytic organic transformations : applications in homogeneous and polymer supported alkene isomerization , and hydrogen deuterium exchange

    E-Print Network [OSTI]

    Erdogan, Gulin

    2012-01-01T23:59:59.000Z

    W. A. Applied homogeneous catalysis with organometallicW. A. Applied homogeneous catalysis with organometallicR. Applied organometallic chemistry and catalysis; Oxford

  2. Homogeneous and Heterogeneous Reaction and Transformation of Hg and Trace Metals in Combustion Systems

    SciTech Connect (OSTI)

    J. Helble; Clara Smith; David Miller

    2009-08-31T23:59:59.000Z

    The overall goal of this project was to produce a working dynamic model to predict the transformation and partitioning of trace metals resulting from combustion of a broad range of fuels. The information provided from this model will be instrumental in efforts to identify fuels and conditions that can be varied to reduce metal emissions. Through the course of this project, it was determined that mercury (Hg) and arsenic (As) would be the focus of the experimental investigation. Experiments were therefore conducted to examine homogeneous and heterogeneous mercury oxidation pathways, and to assess potential interactions between arsenic and calcium. As described in this report, results indicated that the role of SO{sub 2} on Hg oxidation was complex and depended upon overall gas phase chemistry, that iron oxide (hematite) particles contributed directly to heterogeneous Hg oxidation, and that As-Ca interactions occurred through both gas-solid and within-char reaction pathways. Modeling based on this study indicated that, depending upon coal type and fly ash particle size, vaporization-condensation, vaporization-surface reaction, and As-CaO in-char reaction all play a role in arsenic transformations under combustion conditions.

  3. HETEROGENEOUS CATALYSIS RESEARCH MEETING

    E-Print Network [OSTI]

    Authors, Various

    2011-01-01T23:59:59.000Z

    synthesis gas by coal gasification is very expensive andin the cost of coal gasification would have a significantas K co , to promote gasification would be beneficial s1nce

  4. HETEROGENEOUS CATALYSIS RESEARCH MEETING

    E-Print Network [OSTI]

    Authors, Various

    2011-01-01T23:59:59.000Z

    production of SNG or Fischer-Tropsch products Therefore, abe trying to obtain from Fischer-Tropsch synthesis? Answer:intermediates in Fischer-Tropsch synthesis? Answer: It was

  5. HETEROGENEOUS CATALYSIS RESEARCH MEETING

    E-Print Network [OSTI]

    Authors, Various

    2011-01-01T23:59:59.000Z

    is pointed out that coal gasification involves 70% to 80% ofof alkali metals in coal gasification is poorly under- stoodOther methods of catalyzing coal gasification also should be

  6. Homogenization of a Conductive, Convective and Radiative Heat Transfer Problem in a Heterogeneous Domain

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -cooled reactor. It is typically made of many prismatic blocks of graphite in which are inserted the nuclear fuel in the homogenization of heat transfer in periodic porous media where the fluid part is made of long thin parallel in the solid part of the domain and by conduction, convection and radiative transfer in the fluid part (the

  7. catalysis | EMSL

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

    analysis radionuclides aerosols catalysis renewable energy subsurface geological field battery materials catalyst beds geochemistry ion microprobe high sensitivity high mass...

  8. Shining Light on Catalysis | Stanford Synchrotron Radiation Lightsourc...

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

    Shining Light on Catalysis Tuesday, July 19, 2011 - 4:38pm SSRL Conference Room 137-322 Jeroen A. van Bokhoven, Professor for Heterogeneous Catalysis Institute for Chemical and...

  9. Summary Report on New Transmutation Analysis for the Evaluation of Homogeneous and Heterogeneous Options in Fast Reactors

    SciTech Connect (OSTI)

    R. M. Ferrer; S. Bays; M. Pope; B. Forget; W. Skerjanc; M. Asgari

    2008-08-01T23:59:59.000Z

    A 1000 MWth commercial-scale Sodium Fast Reactor (SFR) design was selected as the baseline in this scenario study. Traditional approaches to Light Water Reactor (LWR) Spent Nuclear Fuel (SNF) transuranic waste (TRU) burning in a fast spectrum system have typically focused on the continual homogeneous recycling (reprocessing) of the discharge fast reactor fuel. The effective reduction of transuranic inventories has been quantified through the use of the transuranics conversion ratio (TRU CR). The implicit assumption in the use of this single parameter is a homogeneous fast reactor option where equal weight is given to the destruction of transuranics, either by fission or eventual fission via transmutation. This work explores the potential application of alternative fast reactor fuel cycles in which the minor actinide (MA) component of the TRU is considered ‘waste’, while the plutonium component is considered as fuel. Specifically, a set of potential designs that incorporate radial heterogeneous target assemblies is proposed and results relevant to transmutation and system analysis are presented. In this work we consider exclusively minor actinide-bearing radial targets in a continual reprocessing scenario (as opposed to deep-burn options). The potential use of targets in a deep burn mode is not necessarily ruled out as an option. However, due to work scope constraints and material limit considerations, it was preferred to leave the target assemblies reach either the assumed limit of 200 DPA at discharge or maximum allowable gas pressure caused by helium production from transmutation. The number and specific design of the target assemblies was chosen to satisfy the necessary core symmetry and physical dimensions (available space for a certain amount of mass in an assembly based on an iterated mass density).

  10. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    SciTech Connect (OSTI)

    Andersen, T.; Jensen, R.; Christensen, M. K.; Chorkendorff, I. [Department of Physics, Danish National Research Foundation's Center for Individual Nanoparticle Functionality (CINF), Technical University of Denmark, Building 312, DK-2800 Kgs. Lyngby (Denmark); Pedersen, T.; Hansen, O. [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark)

    2012-07-15T23:59:59.000Z

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m/{Delta}m > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0-5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH{sub 3}.

  11. Selective catalysis utilizing bifunctionalized MCM-41 mesoporous materials

    SciTech Connect (OSTI)

    Strosahl, Kasey Jean

    2005-05-01T23:59:59.000Z

    Selective catalysis is a field that has been under intense investigation for the last 100 years. The most widely used method involves catalysts with stereochemical selectivity. In this type of catalysis, the catalyst controls which reactants will be transformed into the desired product. The secret to employing this type of catalysis, though, is to design the proper catalyst, which can be difficult. One may spend as much time developing the catalyst as spent separating the various products achieved. Another method of selective catalysis is now being explored. The method involves utilizing a multifunctional mesoporous silica catalyst with a gate-keeping capability. Properly functionalized mesoporous materials with well-defined pore morphology and surface properties can provide an ideal three-dimensional environment for anchoring various homogeneous catalysts. These materials can circumvent the multi-sited two-dimensional nature most heterogeneous systems have without adversely impacting the reactant diffusivity. These single-site nanostructured catalysts with ordered geometrical structure are advantageous in achieving high selectivity and reactivity. Mesoporous materials can be prepared to include pores lined homogeneously with tethered catalysts via co-condensation. Additionally, these materials can be reacted with another (RO){sub 3}Si{approx}Z group by using the traditional grafting method; this group is anchored predominantly at the entrances to the pores rather than inside the pores. Thus, if these {approx}Z groups are chosen properly, they can select certain molecules to enter the pores and be converted to products (Scheme 1). In such multifunctional catalysts, the selectivity depends on the discrimination of the gatekeeper. Gate-keeping MCM-41 materials are at the forefront of catalytic substances.

  12. Reaction Selectivity in Heterogeneous Catalysis

    E-Print Network [OSTI]

    Somorjai, Gabor A.

    2010-01-01T23:59:59.000Z

    possible adsorption modes of acrolein to a Pt(111) surface,possible adsorption structures of acrolein on Pt(111) energyand 2 Langmuir exposure of acrolein to Pt(111). Figure taken

  13. INSTITUTE FOR INTEGRATED CATALYSIS Catalysis Research for

    E-Print Network [OSTI]

    . This work includes catalysis for upgrading biomass feedstocks; for chemical energy storage, retrieval

  14. CATALYSIS SCIENCE AND TECHNOLOGY

    SciTech Connect (OSTI)

    M. ABRAMS; R. BAKER; ET AL

    2000-08-01T23:59:59.000Z

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Our objectives were to develop a multidisciplinary team and capabilities to develop a fundamental understanding of homogeneous, heterogeneous, and heterogenized catalysts. With the aid of theoretical chemistry approaches we explored and characterized the chemical reactivity and physical properties of a large number of catalytic systems.

  15. Th/U-233 Multi-recycle in Pressurized Water Reactors: Feasibility Study of Multiple Homogeneous and Heterogeneous Assembly Designs

    E-Print Network [OSTI]

    Kemner, Ken

    Th/U-233 Multi-recycle in Pressurized Water Reactors: Feasibility Study of Multiple Homogeneous in the LWR fuel cycle. The possibility for thorium utilization in a multi-recycle system has also been fuel multi-recycle in current LWRs, focusing on pressurized water reactors (PWRs). Approaches

  16. 2012 Catalysis Lectures

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

    Bert Weckhuysen, who holds the chair of Inorganic Chemistry and Catalysis at Utrecht University, will give a series of catalysis lectures during his sabbatical period at...

  17. Catalysis Workshop

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z C o . C lKieling ,Catalysis Science

  18. Frontiers in Catalysis Science and Engineering Seminar Series

    E-Print Network [OSTI]

    Frontiers in Catalysis Science and Engineering Seminar Series Heterogenized M-Salen Catalysts complexes are widely applied as catalysts for numerous important enantioselective reactions. The reactions catalysis (e.g. Co-salen for epoxide ring-opening or Al-salen conjugate additions of cyanide). The design

  19. Seventh BES (Basic Energy Sciences) catalysis and surface chemistry research conference

    SciTech Connect (OSTI)

    Not Available

    1990-03-01T23:59:59.000Z

    Research programs on catalysis and surface chemistry are presented. A total of fifty-seven topics are included. Areas of research include heterogeneous catalysis; catalysis in hydrogenation, desulfurization, gasification, and redox reactions; studies of surface properties and surface active sites; catalyst supports; chemical activation, deactivation; selectivity, chemical preparation; molecular structure studies; sorption and dissociation. Individual projects are processed separately for the data bases. (CBS)

  20. Heterodimerization of Olefins. 1. Hydrovinylation Reactions of Olefins That Are Amenable to Asymmetric Catalysis

    E-Print Network [OSTI]

    RajanBabu, T. V. "Babu"

    , 151. (b) Chauvin, Y.; Olivier, H. Dimerization and Codimerization. In Applied Homogeneous Catalysis) Jolly, P. W.; Wilke, G. Hydrovinylation. In Applied Homoge- neous Catalysis with Organometallic to Asymmetric Catalysis T. V. RajanBabu,* Nobuyoshi Nomura, Jian Jin, Malay Nandi, Haengsoon Park, and Xiufeng

  1. Zeolite catalysis

    SciTech Connect (OSTI)

    Chu, P.; Garwood, W.E.; Schwartz, A.B.

    1988-11-29T23:59:59.000Z

    This patent describes a process for preparing hydrocarbons boiling in the gasoline and/or distillate range by contacting a feedstock comprising lower molecular weight olefins in a reaction zone under conditions of elevated temperature and pressure with a shape selective crystalline aluminosilicate catalyst, comprising: reducing the non-shape selective surface-cracking and/or surface isomerization activity of the aluminosilicate catalyst by a process comprising: preparing an aqueous solution comprising colloidal silica, optionally an organic directing agent, and a source of hydroxide ions; mixing the aqueous solution with an aqueous dispersion of shape-selective crystalline aluminosilicate to form a homogeneous mixture which is subsequently heated; adding an aqueous solution comprising a source of fluoride ions to the homogeneous mixture to form a reactive composition; heating the reactive composition at a temperature to effectively form a surface-deactivated catalyst comprising a crystalline fluoride-containing silica outer shell on an aluminosilicate; withdrawing the surface-deactivated catalyst from the reactive composition for washing, drying, and calcining of the catalyst; and removing the catalyst to the reaction zone for contact with the olefin feedstock.

  2. SOUTHWEST CATALYSIS 2012 SPRING SYMPOSIUM

    E-Print Network [OSTI]

    ) "Catalysis to Meet the Energy Challenge" 11:00 AM Southwest Catalysis Society Excellence in Applied CatalysisSOUTHWEST CATALYSIS SOCIETY 2012 SPRING SYMPOSIUM April 20, 2012 Duncan Hall - McMurtry Auditorium registration fee is $50, which includes North American Catalysis Society and SWCS yearly membership dues, along

  3. Quantitative, directional measurement of electric field heterogeneity in the

    E-Print Network [OSTI]

    Boxer, Steven G.

    Quantitative, directional measurement of electric field heterogeneity in the active site SUMMARY Extensive structural studies of enzymes have revealed that biological catalysis occurs within substantial electrostatic field heterogeneity, widely differing sensitivities of discrete probes to a set

  4. EMSL - In situ catalysis

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

    situ-catalysis en New generation NMR bioreactor coupled with high-resolution NMR spectroscopy leads to novel discoveries in Moorella http:www.emsl.pnl.govemslwebpublications...

  5. Computational Catalysis and Electrocatalysis

    E-Print Network [OSTI]

    · Hydrogen storage · Photocatalysis #12;Fuel cell electrocatalysts Parallelism between bimetallics projects: photo-catalysis water decomposes over a catalyst producing oxygen and hydrogen From members

  6. Methanol Synthesis over Cu/ZnO/Al2O3: The Active Site in Industrial Catalysis

    SciTech Connect (OSTI)

    Behrens, Malte

    2012-03-28T23:59:59.000Z

    Unlike homogeneous catalysts, heterogeneous catalysts that have been optimized through decades are typically so complex and hard to characterize that the nature of the catalytically active site is not known. This is one of the main stumbling blocks in developing rational catalyst design strategies in heterogeneous catalysis. We show here how to identify the crucial atomic structure motif for the industrial Cu/ZnO/Al{sub 2}O{sub 3} methanol synthesis catalyst. Using a combination of experimental evidence from bulk-, surface-sensitive and imaging methods collected on real high-performance catalytic systems in combination with DFT calculations. We show that the active site consists of Cu steps peppered with Zn atoms, all stabilized by a series of well defined bulk defects and surface species that need jointly to be present for the system to work.

  7. Removal of Toluene in Air by Non Thermal Plasma-Catalysis Hybrid , H. T. Pham

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Removal of Toluene in Air by Non Thermal Plasma-Catalysis Hybrid System A. Khacef , H. T. Pham , A Orléans Cedex 02, France * Institute of Applied Material Science, VAST, 1 Mac Dinh Chi, HCMC, Vietnam with heterogeneous catalysts. This combination can be either single-stage (in-plasma catalysis, IPC) or two

  8. Single-molecule enzymology of RNA: Essential functional groups impact catalysis from a distance

    E-Print Network [OSTI]

    Walter, Nils G.

    Single-molecule enzymology of RNA: Essential functional groups impact catalysis from a distance the site of catalysis have on the individual rate constants. We find that all ribozyme variants show rate constants. This leads to heterogeneous cleavage activity as com- monly observed for RNA enzymes

  9. Physica A 249 (1998) 558564 Mutual catalysis in sets of prebiotic

    E-Print Network [OSTI]

    Pilpel, Yitzhak

    1998-01-01T23:59:59.000Z

    Physica A 249 (1998) 558­564 Mutual catalysis in sets of prebiotic organic molecules : Evolution on the origin of life needs to delineate a chemically rigorous, self-consistent path from highly heterogeneous Replication Domain (GARD) model for explicit kinetic analysis of mutual catalysis in sets of random oligomers

  10. SOUTHWEST CATALYSIS 2013 SPRING SYMPOSIUM

    E-Print Network [OSTI]

    Natelson, Douglas

    -free Substrates" 11:05 AM Southwest Catalysis Society Excellence in Applied Catalysis Award James "Jerry" SpiveySOUTHWEST CATALYSIS SOCIETY 2013 SPRING SYMPOSIUM Friday, April 26, 2013 Grand Hall of the Ley registration fee is $50, which includes North American Catalysis Society and SWCS yearly membership dues, along

  11. Postdoctoral Scholar position Area: Heterogeneous Catalysis

    E-Print Network [OSTI]

    de Leon, Alex R.

    : Immediately Salary: $40,000-$50,000 per year(plus benefits) The Department of Chemical and Petroleum with high performance and novel catalytic processes for efficient energy utilization in an economical evaluation as well as reactor system design and fabrication Creative problem-solving and strong critical

  12. Dendrimer-encapsulated metal nanoparticles: synthesis, characterization, and applications to catalysis 

    E-Print Network [OSTI]

    Niu, Yanhui

    2004-09-30T23:59:59.000Z

    The research in this dissertation examines the chemistry and applications of dendrimers in homogeneous catalysis. We examined interactions between dendrimers and charged probe molecules, prepared dendrimer-encapsulated metal nanoparticles...

  13. Center for Catalysis at Iowa State University

    SciTech Connect (OSTI)

    Kraus, George A.

    2006-10-17T23:59:59.000Z

    The overall objective of this proposal is to enable Iowa State University to establish a Center that enjoys world-class stature and eventually enhances the economy through the transfer of innovation from the laboratory to the marketplace. The funds have been used to support experimental proposals from interdisciplinary research teams in areas related to catalysis and green chemistry. Specific focus areas included: • Catalytic conversion of renewable natural resources to industrial materials • Development of new catalysts for the oxidation or reduction of commodity chemicals • Use of enzymes and microorganisms in biocatalysis • Development of new, environmentally friendly reactions of industrial importance These focus areas intersect with barriers from the MYTP draft document. Specifically, section 2.4.3.1 Processing and Conversion has a list of bulleted items under Improved Chemical Conversions that includes new hydrogenation catalysts, milder oxidation catalysts, new catalysts for dehydration and selective bond cleavage catalysts. Specifically, the four sections are: 1. Catalyst development (7.4.12.A) 2. Conversion of glycerol (7.4.12.B) 3. Conversion of biodiesel (7.4.12.C) 4. Glucose from starch (7.4.12.D) All funded projects are part of a soybean or corn biorefinery. Two funded projects that have made significant progress toward goals of the MYTP draft document are: Catalysts to convert feedstocks with high fatty acid content to biodiesel (Kraus, Lin, Verkade) and Conversion of Glycerol into 1,3-Propanediol (Lin, Kraus). Currently, biodiesel is prepared using homogeneous base catalysis. However, as producers look for feedstocks other than soybean oil, such as waste restaurant oils and rendered animal fats, they have observed a large amount of free fatty acids contained in the feedstocks. Free fatty acids cannot be converted into biodiesel using homogeneous base-mediated processes. The CCAT catalyst system offers an integrated and cooperative catalytic system that performs both esterification (of free fatty acids) and transesterification (of soybean oil) in a one-pot fashion. This will allow the biodiesel producers to use the aforementioned cheap feedstocks without any pretreatment. In addition, the catalyst system is heterogeneous and is highly recyclable and reusable. Although markets currently exist for glycerin, concern is mounting that the price of glycerin may plummet to $.05 - $.10 per pound if future production exceeds demand. Developing a system to make high value chemicals such as 1,3-propanediol from the glycerin stream will add value for biodiesel producers who implement the new technology. Given the fact that both DuPont and Shell chemicals have announced the commercialization of two new PDO-based polymers, a rapid increase of market demand for a cheaper PDO source is very likely. 4. Comparison of actual accomplishments with goals and objectives From our progress reports, the four areas are: 1. Catalyst development (7.4.12.A) 2. Conversion of glycerol (7.4.12.B) 3. Conversion of biodiesel (7.4.12.C) 4. Glucose from starch (7.4.12.D)

  14. Integrative Protein Function Transfer using Factor Graphs and Heterogeneous Data Sources

    E-Print Network [OSTI]

    Mishra, Bud

    Integrative Protein Function Transfer using Factor Graphs and Heterogeneous Data Sources Antonina, translation initiation, enzymatic catalysis, and immune re- sponse. However, for a large portion of proteins

  15. A Hydrogen-Evolving Ni(P2N2)2 Electrocatalyst Covalently Attached to a Glassy Carbon Electrode: Preparation, Characterization, and Catalysis. Comparisons With the Homogeneous Analog

    SciTech Connect (OSTI)

    Das, Atanu K.; Engelhard, Mark H.; Bullock, R. Morris; Roberts, John A.

    2014-07-07T23:59:59.000Z

    A hydrogen-evolving homogeneous Ni(P2N2)2 electrocatalyst with peripheral ester groups has been covalently attached to a 1,2,3-triazolyllithium-terminated glassy carbon electrode. The surface-confined complex is an electroctalyst for hydrogen evolution, showing onset of catalytic current at the same potential as the soluble parent complex. X-ray photoemission spectra show excellent agreement between the coupled and homogeneous species. Coverage approaches a dense monolayer. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy. The XPS measurements were performed at EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

  16. Neutrons for Catalysis: A Workshop on Neutron Scattering Techniques for Studies in Catalysis

    SciTech Connect (OSTI)

    Overbury, Steven {Steve} H [ORNL; Coates, Leighton [ORNL; Herwig, Kenneth W [ORNL; Kidder, Michelle [ORNL

    2011-10-01T23:59:59.000Z

    This report summarizes the Workshop on Neutron Scattering Techniques for Studies in Catalysis, held at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on September 16 and 17, 2010. The goal of the Workshop was to bring experts in heterogeneous catalysis and biocatalysis together with neutron scattering experimenters to identify ways to attack new problems, especially Grand Challenge problems in catalysis, using neutron scattering. The Workshop locale was motivated by the neutron capabilities at ORNL, including the High Flux Isotope Reactor (HFIR) and the new and developing instrumentation at the SNS. Approximately 90 researchers met for 1 1/2 days with oral presentations and breakout sessions. Oral presentations were divided into five topical sessions aimed at a discussion of Grand Challenge problems in catalysis, dynamics studies, structure characterization, biocatalysis, and computational methods. Eleven internationally known invited experts spoke in these sessions. The Workshop was intended both to educate catalyst experts about the methods and possibilities of neutron methods and to educate the neutron community about the methods and scientific challenges in catalysis. Above all, it was intended to inspire new research ideas among the attendees. All attendees were asked to participate in one or more of three breakout sessions to share ideas and propose new experiments that could be performed using the ORNL neutron facilities. The Workshop was expected to lead to proposals for beam time at either the HFIR or the SNS; therefore, it was expected that each breakout session would identify a few experiments or proof-of-principle experiments and a leader who would pursue a proposal after the Workshop. Also, a refereed review article will be submitted to a prominent journal to present research and ideas illustrating the benefits and possibilities of neutron methods for catalysis research.

  17. Catalysis Research for Energy Independence

    E-Print Network [OSTI]

    yields insights into improving the industrial catalyst for oil refining, chemicals processing into chemical fuels. In addition, we conduct applied catalysis research with industrial, academic, and other collaborate with catalysis leaders in academia, industry, and national laboratories. Research in Science

  18. Author's personal copy Catalysis of imido group hydrolysis in a maleimide conjugate

    E-Print Network [OSTI]

    Raines, Ronald T.

    Author's personal copy Catalysis of imido group hydrolysis in a maleimide conjugate Jeet Kaliaa, resulting in undesirable heterogeneity. Here, a chromophoric maleimide is used to demonstrate that both for molybdate and chromate, and provides a strategy for decreasing the heterogeneity of bioconjugates derived

  19. Polyisobutylene as a Polymer Support for Homogeneous Catalysis

    E-Print Network [OSTI]

    Hongfa, Chayanant

    2010-01-14T23:59:59.000Z

    and filtration. PEG is insoluble in hexane, diethyl ether, tert-butylmethyl ether (TBME), isopropyl alcohol, and cold ethanol. These are the solvents usually used for the precipitation process. 14 PEG is usefully soluble in a wide range of solvents... (>80% ee) and high yield (>80%). The PEG-bound Cinchona alkaloid 6 was recovered (8) 11 by solvent precipitation with diethyl ether and recycled through five cycles with p- chlorostyrene as a substrate. The average yield of all 5 cycles was 93...

  20. Phase selectively soluble polymer supports to facilitate homogeneous catalysis

    E-Print Network [OSTI]

    Ortiz-Acosta, Denisse

    2009-05-15T23:59:59.000Z

    Soluble polymers that have phase selective solubility are useful in synthesis because they simplify purification and separation. Such selectively soluble polymers simplify catalyst, reagent, and product recovery and enable the use of Green chemistry...

  1. Homogeneous and Interfacial Catalysis in 3D Controlled Environment | The

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh School football Highdefault Sign In AboutAmes Laboratory

  2. asymmetric catalysis stereoelectronic: Topics by E-print Network

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

    X Lewis Acid Catalysis Brnsted Acid Catalysis X Johnson, Jeff S. 2 Multidimensional free energy relationships in asymmetric catalysis. Open Access Theses and Dissertations...

  3. Magnetic catalysis and inverse magnetic catalysis in QCD

    E-Print Network [OSTI]

    Niklas Mueller; Jan M. Pawlowski

    2015-02-27T23:59:59.000Z

    We investigate the effects of strong magnetic fields on the QCD phase structure at vanishing density by solving the gluon and quark gap equations, and by studying the dynamics of the quark scattering with the four-fermi coupling. The chiral crossover temperature as well as the chiral condensate are computed. For asymptotically large magnetic fields we find magnetic catalysis, while we find inverse magnetic catalysis for intermediate magnetic fields. Moreover, for large magnetic fields the chiral phase transition for massless quarks turns into a crossover. The underlying mechanisms are then investigated analytically within a few simplifications of the full numerical analysis. We find that a combination of gluon screening effects and the weakening of the strong coupling is responsible for the phenomenon of inverse catalysis. In turn, the magnetic catalysis at large magnetic field is already indicated by simple arguments based on dimensionality.

  4. Synthetic Catalysis of Amide Isomerization

    E-Print Network [OSTI]

    Lectka, Thomas

    , they may play other roles in vivo, including the catalysis of protein folding, functioning as auxiliary seem to be a possible way to catalyze protein folding in vitro, and experiments along these lines

  5. Enhanced Micellar Catalysis LDRD.

    SciTech Connect (OSTI)

    Betty, Rita G.; Tucker, Mark David; Taggart, Gretchen; Kinnan, Mark K.; Glen, Crystal Chanea; Rivera, Danielle; Sanchez, Andres; Alam, Todd Michael

    2012-12-01T23:59:59.000Z

    The primary goals of the Enhanced Micellar Catalysis project were to gain an understanding of the micellar environment of DF-200, or similar liquid CBW surfactant-based decontaminants, as well as characterize the aerosolized DF-200 droplet distribution and droplet chemistry under baseline ITW rotary atomization conditions. Micellar characterization of limited surfactant solutions was performed externally through the collection and measurement of Small Angle X-Ray Scattering (SAXS) images and Cryo-Transmission Electron Microscopy (cryo-TEM) images. Micellar characterization was performed externally at the University of Minnesota's Characterization Facility Center, and at the Argonne National Laboratory Advanced Photon Source facility. A micellar diffusion study was conducted internally at Sandia to measure diffusion constants of surfactants over a concentration range, to estimate the effective micelle diameter, to determine the impact of individual components to the micellar environment in solution, and the impact of combined components to surfactant phase behavior. Aerosolized DF-200 sprays were characterized for particle size and distribution and limited chemical composition. Evaporation rates of aerosolized DF-200 sprays were estimated under a set of baseline ITW nozzle test system parameters.

  6. Fuel Synthesis Catalysis Laboratory (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-07-01T23:59:59.000Z

    This fact sheet provides information about Fuel Synthesis Catalysis Laboratory capabilities and applications at NREL's National Bioenergy Center.

  7. Fuel Synthesis Catalysis Laboratory (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-07-01T23:59:59.000Z

    This fact sheet provides information about Fuel Synthesis Catalysis Laboratory capabilities and applications at NREL's National Bioenergy Center.

  8. Laboratory investigations of effective flow behavior in unsaturated heterogeneous sands

    E-Print Network [OSTI]

    Wildenschild, Dorthe

    Laboratory investigations of effective flow behavior in unsaturated heterogeneous sands D, Lyngby Abstract. Two-dimensional unsaturated flow and transport through heterogeneous sand was investigated under controlled laboratory conditions. The unsaturated hydraulic conductivity of five homogeneous

  9. Charge Transfer and Catalysis at the Metal-Support Interface

    E-Print Network [OSTI]

    Baker, Lawrence Robert

    2012-01-01T23:59:59.000Z

    A. ; Miko?ajska, A. Applied Catalysis A: General 2002, 233,T. ; Haruta, M. Applied Catalysis A: General 1998, 169,Albert Vannice, M. Applied Catalysis A: General 1994, 113, (

  10. Heterogeneous Catalysis DOI: 10.1002/anie.201101378

    E-Print Network [OSTI]

    Oxidation The toxic character of CO, which is produced in large amounts from the emerging petrochemical

  11. Charge Transfer and Support Effects in Heterogeneous Catalysis

    E-Print Network [OSTI]

    Hervier, Antoine

    2012-01-01T23:59:59.000Z

    titanium  oxide  electronic  structure  show  that  the  energy and energy applications. 1–3   Among TMOs, titanium  oxide energy  dependent  imaginary  dielectric  functions  obtained  by  spectroscopic  ellipsometry  for  undoped  titanium 

  12. The Role of Catalyst Surface Structure in Heterogeneous Catalysis...

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

    Ceria Nanocrystals as Catalyst and Catalyst Support Apr 23 2014 10:00 AM - 11:00 AM Zili Wu, Chemical Science Division and Center for Nanophase Materials Sciences, ORNL Materials...

  13. Heterogeneous Catalysis DOI: 10.1002/anie.201304610

    E-Print Network [OSTI]

    Iglesia, Enrique

    and Selectivity of Fischer­ Tropsch Synthesis on Ruthenium Catalysts** David D. Hibbitts, Brett T. Loveless, Matthew Neurock,* and Enrique Iglesia* Ru and Co catalyze Fischer­Tropsch synthesis (FTS) with high rates

  14. Control Heterogeneous Catalysis at Atomic and Electronic-level Using

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration would likeConstitution And BylawsMetal-Organic Frameworks | The Ames

  15. Textured Metal Catalysts for Heterogeneous Catalysis - Energy Innovation

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our InstagramStructureProposedPAGESafetyTed Donat AboutTextiles (2010 MECS)

  16. The Role of Catalyst Surface Structure in Heterogeneous Catalysis |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solidSynthesis of 2Dand WaterThe FutureRisk Assessments

  17. Basic Research Needs: Catalysis for Energy

    SciTech Connect (OSTI)

    Bell, Alexis T.; Gates, Bruce C.; Ray, Douglas; Thompson, Michael R.

    2008-03-11T23:59:59.000Z

    The report presents results of a workshop held August 6-8, 2007, by DOE SC Basic Energy Sciences to determine the basic research needs for catalysis research.

  18. Workshop: Synchrotron Applications in Chemical Catalysis | Stanford...

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

    Applications in Chemical Catalysis Tuesday, October 25, 2011 - 8:00am 2011 SSRLLCLS Annual Users Conference This workshop, part of the 2011 SSRLLCLS Annual Users...

  19. Plasma Assisted Catalysis System for NOx Reduction

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

    2 NOXTECH NOXTECH PLASMA ASSISTED CATALYSIS SYSTEM FOR NOx REDUCTION BY NOXTECH With the Support & Cooperation of DOE Noxtech, Inc. *Delaware Corporation registered to do business...

  20. Heterogeneous effects in fast breeder reactors

    E-Print Network [OSTI]

    Gregory, Michael Vladimir

    1973-01-01T23:59:59.000Z

    Heterogeneous effects in fast breeder reactors are examined through development of simple but accurate models for the calculation of a posteriori corrections to a volume-averaged homogeneous representation. Three distinct ...

  1. Essays on economies with heterogeneous labor

    E-Print Network [OSTI]

    Lehr, Brandon Charles

    2010-01-01T23:59:59.000Z

    In this thesis, I study two different economies that consist of heterogeneous labor. By allowing for differences among individuals where previous analyses restricted attention to homogeneous labor, I am able to understand ...

  2. Thermochemical Conversion: Using Heat and Catalysis to Make Biofuels...

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

    Conversion: Using Heat and Catalysis to Make Biofuels and Bioproducts Thermochemical Conversion: Using Heat and Catalysis to Make Biofuels and Bioproducts The Bioenergy...

  3. Bimetallic and Ternary Alloys for Improved Oxygen Reduction Catalysis...

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

    Bimetallic and Ternary Alloys for Improved Oxygen Reduction Catalysis . Bimetallic and Ternary Alloys for Improved Oxygen Reduction Catalysis . Abstract: The research described in...

  4. Column Asymmetric Catalysis for -Lactam Synthesis

    E-Print Network [OSTI]

    Lectka, Thomas

    Column Asymmetric Catalysis for -Lactam Synthesis Ahmed M. Hafez, Andrew E. Taggi, Harald Wack that constitute the packing of a series of "reaction columns". This process was applied to the catalytic- and diastereoselectivity. In the realm of chiral synthesis and drug discovery, asym- metric catalysis1 and solid

  5. Topics in Catalysis ISSN 1022-5528

    E-Print Network [OSTI]

    Frenkel, Anatoly

    1 23 Topics in Catalysis ISSN 1022-5528 Top Catal DOI 10.1007/s11244-013-0053-y Characterization ubiquitous catalytic systems commonly used [1­6]. Despite significant progress made in developing catalysis, the challenge remains in the co-interpretation of their results since these methods are commonly applied

  6. Einstein homogeneous riemannian fibrations 

    E-Print Network [OSTI]

    Araujo, Fatima

    2008-01-01T23:59:59.000Z

    This thesis is dedicated to the study of the existence of homogeneous Einstein metrics on the total space of homogeneous fibrations such that the fibers are totally geodesic manifolds. We obtain the Ricci curvature of ...

  7. Approved Module Information for CH3115, 2014/5 Module Title/Name: Inorganic Chemistry III Module Code: CH3115

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Code: CH3115 School: Engineering and Applied Science Module Type: Standard Module New Module? No Module is provided. The fields of Homogeneous Catalysis and Heterogeneous Catalysis are introduced and basic aspects homogeneous and heterogenous catalytic process), hydroformylation (homogeneous catalysis), ammonia synthesis

  8. "Nanocrystal bilayer for tandem catalysis"

    SciTech Connect (OSTI)

    Yamada, Yusuke; Tsung, Chia Kuang; Huang, Wenyu; Huo, Ziyang; E.Habas, Susan E; Soejima, Tetsuro; Aliaga, Cesar E; Samorjai, Gabor A; Yang, Peidong

    2011-01-24T23:59:59.000Z

    Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalysts

  9. asymmetric catalysis solvent-free: Topics by E-print Network

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

    X Lewis Acid Catalysis Brnsted Acid Catalysis X Johnson, Jeff S. 2 Multidimensional free energy relationships in asymmetric catalysis. Open Access Theses and Dissertations...

  10. Homogenization in non linear dynamics due to frictional contact Peillex G. a

    E-Print Network [OSTI]

    Boyer, Edmond

    homogenization process and its influence on the behavior of a composite under non linear dynamic loading due homogenization process, coupled with an homogenization of the frictional contact, enables replacing the entire in the heterogeneous models are identified by using the relocalization process and a frictional contact dynamic

  11. Introduction and Case Studies The Ratio Plot Under Homogeneity and the Decontaminated Turing

    E-Print Network [OSTI]

    Boehning, Dankmar

    Outline Introduction and Case Studies The Ratio Plot Under Homogeneity and the Decontaminated Introduction and Case Studies The Ratio Plot Under Homogeneity and the Decontaminated Turing The Ratio Plot The Ratio Plot Under Homogeneity and the Decontaminated Turing The Ratio Plot and Structured Heterogeneity

  12. Nanocrystal assembly for tandem catalysis

    DOE Patents [OSTI]

    Yang, Peidong; Somorjai, Gabor; Yamada, Yusuke; Tsung, Chia-Kuang; Huang, Wenyu

    2014-10-14T23:59:59.000Z

    The present invention provides a nanocrystal tandem catalyst comprising at least two metal-metal oxide interfaces for the catalysis of sequential reactions. One embodiment utilizes a nanocrystal bilayer structure formed by assembling sub-10 nm platinum and cerium oxide nanocube monolayers on a silica substrate. The two distinct metal-metal oxide interfaces, CeO.sub.2--Pt and Pt--SiO.sub.2, can be used to catalyze two distinct sequential reactions. The CeO.sub.2--Pt interface catalyzed methanol decomposition to produce CO and H.sub.2, which were then subsequently used for ethylene hydroformylation catalyzed by the nearby Pt--SiO.sub.2 interface. Consequently, propanal was selectively produced on this nanocrystal bilayer tandem catalyst.

  13. Magnetic Catalysis vs Magnetic Inhibition

    E-Print Network [OSTI]

    Kenji Fukushima; Yoshimasa Hidaka

    2012-09-06T23:59:59.000Z

    We discuss the fate of chiral symmetry in an extremely strong magnetic field B. We investigate not only quark fluctuations but also neutral meson effects. The former would enhance the chiral-symmetry breaking at finite B according to the Magnetic Catalysis, while the latter would suppress the chiral condensate once B exceeds the scale of the hadron structure. Using a chiral model we demonstrate how neutral mesons are subject to the dimensional reduction and the low dimensionality favors the chiral-symmetric phase. We point out that this effect, the Magnetic Inhibition, can be a feasible explanation for recent lattice-QCD data indicating the decreasing behavior of the chiral-restoration temperature with increasing B.

  14. On the role of interfacial hydrogen bonds in "on-water" catalysis

    E-Print Network [OSTI]

    Kristof Karhan; Rustam Z. Khaliullin; Thomas D. Kühne

    2014-08-21T23:59:59.000Z

    Numerous experiments have demonstrated that many classes of organic reactions exhibit increased reaction rates when performed in heterogeneous water emulsions. Despite enormous practical importance of the observed "on-water" catalytic effect and several mechanistic studies, its microscopic origins remains unclear. In this work, the second generation Car-Parrinello molecular dynamics method is extended to self-consistent charge density-functional based tight-binding in order to study "on-water" catalysis of the Diels-Alder reaction between dimethyl azodicarboxylate and quadricyclane. We find that the stabilization of the transition state by dangling hydrogen bonds exposed at the aqueous interfaces plays a significantly smaller role in "on-water" catalysis than has been suggested previously.

  15. Low-Temperature Hydrocarbon/CO Oxidation Catalysis in Support...

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

    rappe.pdf More Documents & Publications Low-Temperature HydrocarbonCO Oxidation Catalysis in Support of HCCI Emission Control Low-Temperature HydrocarbonCO Oxidation Catalysis in...

  16. UNCORRECTEDPROOF Applied Catalysis B: Environmental 793 (2000) 19

    E-Print Network [OSTI]

    Jardim, Wilson de Figueiredo

    2000-01-01T23:59:59.000Z

    UNCORRECTEDPROOF Applied Catalysis B: Environmental 793 (2000) 1­9 Catalyst deactivation in the gas;UNCORRECTEDPROOF 2 R.M. Alberici et al. / Applied Catalysis B: Environmental 793 (2000) 1­9 when photo-oxidizing 1

  17. aqueous phase catalysis: Topics by E-print Network

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

    corroborate asymmetry of catalysis in F0F1-ATP synthase. Zarrabi, Nawid; Diez, Manuel; Graeber, Peter; Wrachtrup, Joerg; Boersch, Michael 2007-01-01 292 Magnetic catalysis in hot...

  18. Catalysis by Supported Gold Nanoclusters D. Wayne Goodman

    E-Print Network [OSTI]

    Goodman, Wayne

    by the selective oxidation of propylene to propylene oxide by gold,[4] alkene and arene hydrogenation catalysis,[5

  19. SouthWest Catalysis Society 2011 Spring Symposium

    E-Print Network [OSTI]

    Natelson, Douglas

    Award for Excellence in Applied Catalysis later in the day. On-site registration will begin at 7:30 AMSouthWest Catalysis Society 2011 Spring Symposium April 15, 2011 BioScience Research Collaborative in teaching and in the field of catalysis. Additionally, the Society is proud to present the inaugural SWCS

  20. Geometrically induced magnetic catalysis and critical dimensions

    E-Print Network [OSTI]

    Antonino Flachi; Kenji Fukushima; Vincenzo Vitagliano

    2015-02-21T23:59:59.000Z

    We discuss the combined effect of magnetic fields and geometry in interacting fermionic systems. At leading order in the heat-kernel expansion, the infrared singularity (that in flat space leads to the magnetic catalysis) is regulated by the chiral gap effect and the catalysis is deactivated by effect of the curvature. We discover that an infrared singularity may reappear from higher-order terms in the heat kernel expansion leading to a novel form of geometrically induced magnetic catalysis (absent in flat space). The dynamical mass squared is then modified not only due to the chiral gap effect by an amount proportional to the curvature, but also by a magnetic shift $\\propto (4-D)eB$ where $D$ represents the number of space-time dimensions. We argue that $D=4$ is a critical dimension across which the behaviour of the magnetic shift changes qualitatively.

  1. Geometrically induced magnetic catalysis and critical dimensions

    E-Print Network [OSTI]

    Flachi, Antonino; Vitagliano, Vincenzo

    2015-01-01T23:59:59.000Z

    We discuss the combined effect of magnetic fields and geometry in interacting fermionic systems. At leading order in the heat-kernel expansion, the infrared singularity (that in flat space leads to the magnetic catalysis) is regulated by the chiral gap effect and the catalysis is deactivated by effect of the curvature. We discover that an infrared singularity may reappear from higher-order terms in the heat kernel expansion leading to a novel form of geometrically induced magnetic catalysis (absent in flat space). The dynamical mass squared is then modified not only due to the chiral gap effect by an amount proportional to the curvature, but also by a magnetic shift $\\propto (4-D)eB$ where $D$ represents the number of space-time dimensions. We argue that $D=4$ is a critical dimension across which the behaviour of the magnetic shift changes qualitatively.

  2. Geometrically induced magnetic catalysis and critical dimensions

    E-Print Network [OSTI]

    Antonino Flachi; Kenji Fukushima; Vincenzo Vitagliano

    2015-04-27T23:59:59.000Z

    We discuss the combined effect of magnetic fields and geometry in interacting fermionic systems. At leading order in the heat-kernel expansion, the infrared singularity (that in flat space leads to the magnetic catalysis) is regulated by the chiral gap effect, and the catalysis is deactivated by the effect of the scalar curvature. We discover that an infrared singularity is found in higher-order terms that mix the magnetic field with curvature, and these lead to a novel form of geometrically induced magnetic catalysis. The dynamical mass squared is then modified not only due to the chiral gap effect by an amount proportional to the curvature, but also by a magnetic shift $\\propto (4-D)eB$, where $D$ represents the number of space-time dimensions. We argue that $D=4$ is a critical dimension across which the behavior of the magnetic shift changes qualitatively.

  3. Mapping parallel programs to heterogeneous multi-core systems 

    E-Print Network [OSTI]

    Grewe, Dominik

    2014-06-27T23:59:59.000Z

    Heterogeneous computer systems are ubiquitous in all areas of computing, from mobile to high-performance computing. They promise to deliver increased performance at lower energy cost than purely homogeneous, CPU-based ...

  4. Simulation and design optimization of wave propagation in heterogeneous materials

    E-Print Network [OSTI]

    Saà-Seoane, Joel

    2014-01-01T23:59:59.000Z

    Propagation of waves through heterogeneous structured materials has been the focus of considerable research in recent years. These materials consist of quasi periodic geometries combining two or more piecewise homogeneous ...

  5. Effective hydraulic conductivity of bounded, strongly heterogeneous porous media

    E-Print Network [OSTI]

    Tartakovsky, Daniel M.

    Effective hydraulic conductivity of bounded, strongly heterogeneous porous media Evangelos K of Arizona, Tucson Abstract. We develop analytical expressions for the effective hydraulic conductivity Ke boundaries. The log hydraulic conductivity Y forms a Gaussian, statistically homogeneous and anisotropic

  6. ONE-DIMENSIONAL PSEUDO-HOMOGENEOUS PACKED BED REACTOR MODELING INCLUDING NO-CO KINETICS

    E-Print Network [OSTI]

    Srinivasan, Anand

    2011-08-31T23:59:59.000Z

    major way to meet these low standards is to employ exhaust aftertreatment devices using heterogeneous catalysis for chemical species conversion. This is because the temperature is too low and the residence time is too short for chemical reactions... the chemical reactions happening on the surface of the washcoat. Moreover, collaborative efforts investigating chemical kinetics for exhaust aftertreatment between the Mechanical (ME) and Chemical and Petroleum Engineering (CPE) Departments...

  7. Homogenization of the criticality spectral equation in neutron transport

    E-Print Network [OSTI]

    Bal, Guillaume

    for the neutron transport equation in a periodic heterogeneous domain, modeling the criticality study of nuclearHomogenization of the criticality spectral equation in neutron transport Gr'egoire Allaire \\Lambda problem. This result justifies and improves the engineering procedure used in practice for nuclear reactor

  8. Defining Least Community as a Homogeneous Group in Complex Networks

    E-Print Network [OSTI]

    Jiang, Bin

    2015-01-01T23:59:59.000Z

    This paper introduces a new concept of least community that is as homogeneous as a random graph, and develops a new community detection algorithm from the perspective of homogeneity or heterogeneity. Based on this concept, we adopt head/tail breaks - a newly developed classification scheme for data with a heavy-tailed distribution - and rely on edge betweenness given its heavy-tailed distribution to iteratively partition a network into many heterogeneous and homogeneous communities. Surprisingly, the derived communities for any self-organized and/or self-evolved large networks demonstrate very striking power laws, implying that there are far more small communities than large ones. This notion of far more small things than large ones constitutes a new fundamental way of thinking for community detection. Keywords: head/tail breaks, ht-index, scaling, k-means, natural breaks, and classification

  9. OSCAR Homogeneous andOSCAR Homogeneous and Heterogeneous Multicores, Compilerg , p

    E-Print Network [OSTI]

    Kasahara, Hironori

    Supercomputer "KEI": 10PFLOPS IBM Blue Gene/L: 360TFLOPS, 2005, BG/Q :20PFLOPS 2011BG/Q :20PFLOPS.2011, BlueWaters

  10. Chemical Sciences and Engineering Division

    E-Print Network [OSTI]

    Kemner, Ken

    · Heterogeneous and Homogenous Catalysis · Fuel Cell and Electrocatalysis Electrochemical Energy Storage Anthony and Diagnostics · Emerging Materials and Technology Nuclear & Environmental Processes National Security David

  11. Nanoscale Advances in Catalysis and Energy Applications

    SciTech Connect (OSTI)

    Li, Yimin; Somorjai, Gabor A.

    2010-05-12T23:59:59.000Z

    In this perspective, we present an overview of nanoscience applications in catalysis, energy conversion, and energy conservation technologies. We discuss how novel physical and chemical properties of nanomaterials can be applied and engineered to meet the advanced material requirements in the new generation of chemical and energy conversion devices. We highlight some of the latest advances in these nanotechnologies and provide an outlook at the major challenges for further developments.

  12. USD Catalysis Group for Alternative Energy

    SciTech Connect (OSTI)

    James D. Hoefelmeyer, Ranjit Koodali, Grigoriy Sereda, Dan Engebretson, Hao Fong, Jan Puszynski, Rajesh Shende, Phil Ahrenkiel

    2012-03-13T23:59:59.000Z

    The South Dakota Catalysis Group (SDCG) is a collaborative project with mission to develop advanced catalysts for energy conversion with two primary goals: (1) develop photocatalytic systems in which polyfunctionalized TiO2 are the basis for hydrogen/oxygen synthesis from water and sunlight (solar fuels group), (2) develop new materials for hydrogen utilization in fuel cells (fuel cell group). In tandem, these technologies complete a closed chemical cycle with zero emissions.

  13. Blue Ruthenium Dimer Catalysis for Hydrogen Generation | Advanced...

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

    | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Blue Ruthenium Dimer Catalysis for Hydrogen Generation APRIL 15, 2013 Bookmark and Share Key...

  14. "Seeing" hydrogen atoms to unveil enzyme catalysis | ornl.gov

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

    "Seeing" hydrogen atoms to unveil enzyme catalysis Image shows nuclear density maps in the active site of DHFR where the catalytic group Asp27 and substrate folate have...

  15. Catalysis by Design - Theoretical and Experimental Studies of...

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

    Lean NOx Traps - Microstructural Studies of Real World and Model Catalysts Catalysts via First Principles Catalysis by Design: Bridging the Gap between Theory and Experiments...

  16. Catalysis by Design: Bridging the Gap between Theory and Experiments...

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

    between Theory and Experiments Catalysis by Design: Bridging the Gap between Theory and Experiments Poster presentation at the 2007 Diesel Engine-Efficiency & Emissions Research...

  17. Catalysis by Design: Bridging the Gap Between Theory and Experiments...

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

    Between Theory and Experiments at Nanoscale Level Catalysis by Design: Bridging the Gap Between Theory and Experiments at Nanoscale Level Studies on a simple platinum-alumina...

  18. End Functinalization of Polyisobutylenes and their Applications in Dyeing Polyolefins and in Homogeneous Catalysis

    E-Print Network [OSTI]

    Boralugodage, Nilusha P

    2013-06-05T23:59:59.000Z

    by electrophilic aromatic substitution reactions of PIB-diazonium salt 47a and 51a. ..................... 39 FIGUIRE 8. UV_vis Spectra of solutions of PIB bound azo dyes 52, 54, 55 and 56 in heptane..., conventional radical, anionic 2 or cationic polymerization methods offer very limited possibilities of using directly functional monomers due to their secondary interactions with initiator/catalyst systems which consist of metal salts. Therefore, post...

  19. A BRIEF HISTORY OF INDUSTRIAL CATALYSIS

    E-Print Network [OSTI]

    Heinemann, Heinz

    2013-01-01T23:59:59.000Z

    Dealkylation Catalytic Coal Liquefaction and Gasification a)Liquefaction Gasification c) IX Methanation Heterogeneous~IQUEFACTION AND GASIFICATION a) Liquefaction Production of

  20. Neutrons for Catalysis: A Workshop on Neutron Scattering Techniques for Studies in Catalysis

    E-Print Network [OSTI]

    Pennycook, Steve

    -EM Fischer Tropsch Catalysis on Fe- or Co-catalysts, ,,CTL" Coal to Liquids ­ ,a rough (?) analogy #12;Peter Albers, AQ-EM Carbonaceous Deposits on Catalysts #12;Peter Albers, AQ-EM IINS on Coked Catalysts from Industrial Plants High-temperature and low-temperature cokes deposited on catalysts during

  1. Frontiers in Catalysis Science and Engineering Seminar Series

    E-Print Network [OSTI]

    Frontiers in Catalysis Science and Engineering Seminar Series "Frustrated Lewis Pairs": Metal and applied to develop metal-free hydrogenations for C=N bonds in a variety of organic substrates. In addition, alkynes, cyclopropanes, CO2 and N2O. The implications of the discovery of such systems to catalysis

  2. Materials and interfaces for catalysis, separation, storage, and environmental applications

    E-Print Network [OSTI]

    Li, Mo

    Materials and interfaces for catalysis, separation, storage, and environmental applications collaborative effort in cutting-edge fundamental and applied research to discover and develop polymeric' problems such as inexpensive CO2 capture, energy-efficient and high-performance catalysis and separations

  3. Lithium Diisopropylamide-Mediated Enolization: Catalysis by Hemilabile Ligands

    E-Print Network [OSTI]

    Collum, David B.

    Lithium Diisopropylamide-Mediated Enolization: Catalysis by Hemilabile Ligands Antonio Ramirez of a lithium diisopropylamide (LDA)-mediated ester enolization. Hemilabile amino ether MeOCH2CH2NMe2, binding-based catalysis are thwarted by the occlusion of the catalyst on the lithium salt products and byproducts (eq 1

  4. Dynamic control of catalysis within biological cells

    E-Print Network [OSTI]

    Biman Jana; Biman Bagchi

    2011-05-26T23:59:59.000Z

    We develop a theory of enzyme catalysis within biological cells where the substrate concentration [S](t) is time dependent, in contrast to the Michaelis-Menten theory that assumes a steady state. We find that the time varying concentration can combine, in a non-linear way, with the ruggedness of the free energy landscape of enzymes (discovered both in single molecule studies and in simulations) to provide a highly efficient switch (or, bifurcation) between two catalytically active states, at a critical substrate concentration. This allows a dynamic control of product synthesis in cell.

  5. Microgrids and Heterogeneous Power Quality and Reliability

    SciTech Connect (OSTI)

    LaCommare, Kristina; Marnay, Chris

    2007-10-01T23:59:59.000Z

    This paper describes two stylized alternative visions of how the power system might evolve to meet future requirements for the high quality electricity service that modern digital economies demand, a supergrids paradigm and a dispersed paradigm. Some of the economics of the dispersed vision are explored, and perspectives are presented on both the choice of homogeneous universal power quality upstream in the electricity supply chain and on the extremely heterogeneous requirements of end-use loads. It is argued that meeting the demanding requirements of sensitive loads by local provision of high quality power may be more cost effective than increasing the quality of universal homogeneous supply upstream in the legacy grid. Finally, the potential role of microgrids in delivering heterogeneous power quality is demonstrated by reference to two ongoing microgrid tests in the U.S. and Japan.

  6. Impact of structured heterogeneities on reactive two-phase porous flow

    E-Print Network [OSTI]

    Reeves, Daniel

    Two-phase flow through heterogeneous media leads to scale-free distributions of irregularly shaped pockets of one fluid trapped within the other. Although reactions within these fluids are often modeled at the homogeneous ...

  7. Intrinsic heterogeneity in the survival and proliferation capacities of naïve CD8? T cells

    E-Print Network [OSTI]

    Mahajan, Vinay Subhash

    2009-01-01T23:59:59.000Z

    This thesis describes the identification and characterization of a novel 'layer' of intrinsic non-genetic functional heterogeneity within the seemingly homogeneous naive CD8? T cell population in their survival and ...

  8. On the depinning of a driven drop on a heterogeneous substrate

    E-Print Network [OSTI]

    Thiele, Uwe; Knobloch, Edgar

    2006-01-01T23:59:59.000Z

    contrasts and driving strengths µ. The thin lines corresponddriving the typical situation on a homogeneous substrate is as shown in ?gure 3 (dashed line).line (red online). heterogeneity. For very small driving it

  9. ChE 152, Winter 2015 Heterogeneous Kinetics and Reaction Engineering

    E-Print Network [OSTI]

    Low, Steven H.

    Graw-Hill, New York, 1981. 2. G.F. Froment and K.B. Bischoff, Chemical Reactor Analysis and Design, 2nd ed. Wiley, New York, 1990. 3. J.M. Thomas and W.J. Thomas, Principles and Practice of Heterogeneous Catalysis Reactors A. Dispersion (D&D, Chapter 8) B. Fixed-Bed Reactor Models (D&D, Chapter 10) C. Other

  10. Low-Temperature Hydrocarbon/CO Oxidation Catalysis in Support...

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

    National Laboratory U.S. Department of Energy Low-Temperature HydrocarbonCO Oxidation Catalysis in Support of HCCI Emission Control Ken Rapp, Liyu Li, Jonathan Male, Dave King...

  11. Low-Temperature Hydrocarbon/CO Oxidation Catalysis in Support...

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

    D.C. acep03rappe.pdf More Documents & Publications Low-Temperature HydrocarbonCO Oxidation Catalysis in Support of HCCI Emission Control Low-Temperature HydrocarbonCO...

  12. Low-Temperature Hydrocarbon/CO Oxidation Catalysis in Support...

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

    (OFCVT). deer07rappe.pdf More Documents & Publications Low-Temperature HydrocarbonCO Oxidation Catalysis in Support of HCCI Emission Control Low-Temperature HydrocarbonCO...

  13. Redox, haem and CO in enzymatic catalysis and regulation

    E-Print Network [OSTI]

    Ragsdale, Stephen W.

    The present paper describes general principles of redox catalysis and redox regulation in two diverse systems. The first is microbial metabolism of CO by the Wood–Ljungdahl pathway, which involves the conversion of CO or ...

  14. Theoretical investigation of solar energy conversion and water oxidation catalysis

    E-Print Network [OSTI]

    Wang, Lee-Ping

    2011-01-01T23:59:59.000Z

    Solar energy conversion and water oxidation catalysis are two great scientific and engineering challenges that will play pivotal roles in a future sustainable energy economy. In this work, I apply electronic structure ...

  15. Frontiers in Catalysis Science and Engineering Materials Science

    E-Print Network [OSTI]

    Frontiers in Catalysis Science and Engineering Materials Science Chemical Imaging Date: May 13 the quality of human life but also critical to our survival. To power the planet for a better future

  16. Catalysis Working Group Kick-Off Meeting Agenda

    Broader source: Energy.gov [DOE]

    Agenda for the kick-off meeting of the U.S. Department of Energy Fuel Cell Technologies Program's Catalysis Working Group, held May 14, 2012, in Arlington, Virginia.

  17. Lean NOx Trap Catalysis for Lean Natural Gas Engine Applications

    SciTech Connect (OSTI)

    Parks, II, James E [ORNL; Storey, John Morse [ORNL; Theiss, Timothy J [ORNL; Ponnusamy, Senthil [ORNL; Ferguson, Harley Douglas [ORNL; Williams, Aaron M [ORNL; Tassitano, James B [ORNL

    2007-09-01T23:59:59.000Z

    Distributed energy is an approach for meeting energy needs that has several advantages. Distributed energy improves energy security during natural disasters or terrorist actions, improves transmission grid reliability by reducing grid load, and enhances power quality through voltage support and reactive power. In addition, distributed energy can be efficient since transmission losses are minimized. One prime mover for distributed energy is the natural gas reciprocating engine generator set. Natural gas reciprocating engines are flexible and scalable solutions for many distributed energy needs. The engines can be run continuously or occasionally as peak demand requires, and their operation and maintenance is straightforward. Furthermore, system efficiencies can be maximized when natural gas reciprocating engines are combined with thermal energy recovery for cooling, heating, and power applications. Expansion of natural gas reciprocating engines for distributed energy is dependent on several factors, but two prominent factors are efficiency and emissions. Efficiencies must be high enough to enable low operating costs, and emissions must be low enough to permit significant operation hours, especially in non-attainment areas where emissions are stringently regulated. To address these issues the U.S. Department of Energy and the California Energy Commission launched research and development programs called Advanced Reciprocating Engine Systems (ARES) and Advanced Reciprocating Internal Combustion Engines (ARICE), respectively. Fuel efficiency and low emissions are two primary goals of these programs. The work presented here was funded by the ARES program and, thus, addresses the ARES 2010 goals of 50% thermal efficiency (fuel efficiency) and <0.1 g/bhp-hr emissions of oxides of nitrogen (NOx). A summary of the goals for the ARES program is given in Table 1-1. ARICE 2007 goals are 45% thermal efficiency and <0.015 g/bhp-hr NOx. Several approaches for improving the efficiency and emissions of natural gas reciprocating engines are being pursued. Approaches include: stoichiometric engine operation with exhaust gas recirculation and three-way catalysis, advanced combustion modes such as homogeneous charge compression ignition, and extension of the lean combustion limit with advanced ignition concepts and/or hydrogen mixing. The research presented here addresses the technical approach of combining efficient lean spark-ignited natural gas combustion with low emissions obtained from a lean NOx trap catalyst aftertreatment system. This approach can be applied to current lean engine technology or advanced lean engines that may result from related efforts in lean limit extension. Furthermore, the lean NOx trap technology has synergy with hydrogen-assisted lean limit extension since hydrogen is produced from natural gas during the lean NOx trap catalyst system process. The approach is also applicable to other lean engines such as diesel engines, natural gas turbines, and lean gasoline engines; other research activities have focused on those applications. Some commercialization of the technology has occurred for automotive applications (both diesel and lean gasoline engine vehicles) and natural gas turbines for stationary power. The research here specifically addresses barriers to commercialization of the technology for large lean natural gas reciprocating engines for stationary power. The report presented here is a comprehensive collection of research conducted by Oak Ridge National Laboratory (ORNL) on lean NOx trap catalysis for lean natural gas reciprocating engines. The research was performed in the Department of Energy's ARES program from 2003 to 2007 and covers several aspects of the technology. All studies were conducted at ORNL on a Cummins C8.3G+ natural gas engine chosen based on industry input to simulate large lean natural gas engines. Specific technical areas addressed by the research include: NOx reduction efficiency, partial oxidation and reforming chemistry, and the effects of sulfur poisons on the partial oxidation

  18. Nanoscale heterogeneity at the aqueous electrolyte-electrode interface

    E-Print Network [OSTI]

    David T. Limmer; Adam P. Willard

    2014-10-06T23:59:59.000Z

    Using molecular dynamics simulations, we reveal emergent properties of hydrated electrode interfaces that while molecular in origin are integral to the behavior of the system across long times scales and large length scales. Specifically, we describe the impact of a disordered and slowly evolving adsorbed layer of water on the molecular structure and dynamics of the electrolyte solution adjacent to it. Generically, we find that densities and mobilities of both water and dissolved ions are spatially heterogeneous in the plane parallel to the electrode over nanosecond timescales. These and other recent results are analyzed in the context of available experimental literature from surface science and electrochemistry. We speculate on the implications of this emerging microscopic picture on the catalytic proficiency of hydrated electrodes, offering an new direction for study in heterogeneous catalysis at the nanoscale.

  19. Ice Nucleation on Carbon Surface Supports the Classical Theory for Heterogeneous Nucleation

    E-Print Network [OSTI]

    Cabriolu, Raffaela

    2015-01-01T23:59:59.000Z

    The prevalence of heterogeneous nucleation in nature was explained qualitatively by the classical theory for heterogeneous nucleation established over more than 60 years ago, but the quantitative validity and the key conclusions of the theory have remained unconfirmed. Employing the forward flux sampling method and the coarse-grained water model mW, we explicitly computed the heterogeneous ice nucleation rates in the supercooled water on a graphitic surface at various temperatures. The independently calculated ice nucleation rates were found to fit well according to the classical theory for heterogeneous nucleation. The fitting procedure further yields the estimate of the potency factor which measures the ratio of the heterogeneous nucleation barrier to the homogeneous nucleation barrier. Remarkably, the estimated potency factor agrees quantitatively with the volumetric ratio of the critical nuclei between the heterogeneous and homogeneous nucleation. Our numerical study thus provides a strong support to the ...

  20. Critical Path and Area Based Scheduling of Parallel Task Graphs on Heterogeneous Platforms

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Critical Path and Area Based Scheduling of Parallel Task Graphs on Heterogeneous Platforms Tchimou research has been done in the context of single homogeneous clus- ters, heterogeneous platforms have become) a novel "virtual" cluster methodology for handling platform het- erogeneity; (ii) a novel task placement

  1. Applied Catalysis B: Environmental 140141 (2013) 468477 Contents lists available at SciVerse ScienceDirect

    E-Print Network [OSTI]

    Alvarez, Pedro J.

    2013-01-01T23:59:59.000Z

    Applied Catalysis B: Environmental 140­141 (2013) 468­477 Contents lists available at SciVerse ScienceDirect Applied Catalysis B: Environmental journal homepage: www

  2. Value iteration for (switched) homogeneous systems

    E-Print Network [OSTI]

    Dahleh, Munther A.

    In this note, we prove that dynamic programming value iteration converges uniformly for discrete-time homogeneous systems and continuous-time switched homogeneous systems. For discrete-time homogeneous systems, rather than ...

  3. HETEROGENEOUS MULTIPROCESSOR MAPPING FOR REAL-TIME STREAMING SYSTEMS

    E-Print Network [OSTI]

    Gerstlauer, Andreas

    address the problem of multi-objective mapping of SDF graphs onto heterogeneous multi-processor platforms can be modeled by synchronous data flow (SDF) graphs [1]. Multiprocessor mapping of an SDF graph were focused on SDF mapping on homogeneous multiprocessors [1][2]. More recent ap- proaches have

  4. An Analysis of Heterogeneity in Futuristic Unmanned Vehicle Systems

    E-Print Network [OSTI]

    Cummings, Mary "Missy"

    and with enough automation aboard unmanned vehicles, inverting the multiple operators to single-vehicle control1 An Analysis of Heterogeneity in Futuristic Unmanned Vehicle Systems C.E. NEHME M.L. CUMMINGS paradigm is possible. These studies, however, have generally focused on homogeneous teams of vehicles

  5. Heterogeneity of Nucleotide Frequencies Among Evolutionary Lineages and Phylogenetic Inference

    E-Print Network [OSTI]

    Rosenberg, Michael S.

    Heterogeneity of Nucleotide Frequencies Among Evolutionary Lineages and Phylogenetic Inference is the homogeneity of nucleotide frequencies among taxa, which refers to the equality of the nucleotide frequency bias among species. Changes in nucleotide frequency among different lineages in a data set are thought

  6. Heterogeneous cavitation in liquid helium 4 near a glass plate

    E-Print Network [OSTI]

    Caupin, Frédéric

    Heterogeneous cavitation in liquid helium 4 near a glass plate X. Chavanne, S. Balibar and F wave to study cavitation, i.e. the nucleation of bubbles, in liquid helium 4 near a clean glass plate and threshold pressures in the range 0 to -3 bar, significantly less negative than for homogeneous cavitation

  7. Some General Themes in Catalysis at LANL

    SciTech Connect (OSTI)

    Gordon, John C. [Los Alamos National Laboratory

    2012-07-19T23:59:59.000Z

    Some general themes in catalysis at LANL are: (1) Storage and release of energy within chemical bonds (e.g. H{sub 2} storage in and release from covalent bonds, N{sub 2} functionalization, CO{sub 2} functionalization, H{sub 2} oxidation/evolution, O{sub 2} reduction/evolution); (2) Can we control the chemistry of reactive substrates to effect energy relevant transformations in non-traditional media (e.g. can we promote C-C couplings, dehydrations, or hydrogenations in water under relatively mild conditions)? (3) Can we supplant precious metal or rare earth catalysts to effect these transformations, by using earth abundant metals/elements instead? Can we use organocatalysis and circumvent the use of metals completely? (4) Can we improve upon existing rare earth catalyst systems (e.g. in rare earth oxides pertinent to fluid cracking or polymerization) and reduce amounts required for catalytic efficacy? Carbohydrates can be accessed from non-food based biomass sources such as woody residues and switchgrass. After extracted from the plant source, our goal is to upgrade these classes of molecules into useful fuels.

  8. E-Print Network 3.0 - alkane oxidation catalysis Sample Search...

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

    hydrogen... Reforming of Methane 10 Gas Phase Incorporation of Pd onto Iron-Ceria Aerogels for Water Gas Shift Catalysis... at the 20 North American Meeting of the Catalysis...

  9. Applied Catalysis A: General 243 (2003) 1524 On the potential role of hydroxyl groups in

    E-Print Network [OSTI]

    Marks, Laurence D.

    2003-01-01T23:59:59.000Z

    Applied Catalysis A: General 243 (2003) 15­24 On the potential role of hydroxyl groups in CO.K. Costello et al. / Applied Catalysis A: General 243 (2003) 15­24 sensitivity may also account, in part

  10. Applied Catalysis A: General 392 (2011) 5768 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    Auerbach, Scott M.

    2011-01-01T23:59:59.000Z

    Applied Catalysis A: General 392 (2011) 57­68 Contents lists available at ScienceDirect Applied Catalysis A: General journal homepage: www.elsevier.com/locate/apcata Liquid phase aldol condensation

  11. GTPase Catalysis by Ras and Other G-proteins: Insights from Substrate Directed SuperImposition

    E-Print Network [OSTI]

    Kosloff, Mickey

    GTPase Catalysis by Ras and Other G-proteins: Insights from Substrate Directed Super usage of similar approaches to comparison of enzyme catalytic machineries. We applied SDSI to various G catalysis; GTPase; guanine nucleotides; conformational rearrangement; structure comparison

  12. Applied Catalysis B: Environmental 105 (2011) 5060 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    Frenkel, Anatoly

    2011-01-01T23:59:59.000Z

    Applied Catalysis B: Environmental 105 (2011) 50­60 Contents lists available at ScienceDirect Applied Catalysis B: Environmental journal homepage: www.elsevier.com/locate/apcatb Cobalt

  13. acid-base catalysis ii: Topics by E-print Network

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

    corroborate asymmetry of catalysis in F0F1-ATP synthase. Zarrabi, Nawid; Diez, Manuel; Graeber, Peter; Wrachtrup, Joerg; Boersch, Michael 2007-01-01 232 Magnetic catalysis in hot...

  14. Gold(I)-Mediated Nucleophilic Additions to Allenes: from Enantioselective Catalysis to Supramolecular Chemistry

    E-Print Network [OSTI]

    Wang, Zhan

    2012-01-01T23:59:59.000Z

    supramolecular catalysis where the capsule itself serves as a molecular reaction vessel, product can bind competitively with the starting material.

  15. Security-Aware Resource Allocation for Real-Time Parallel Jobs on Homogeneous

    E-Print Network [OSTI]

    Qin, Xiao

    processing systems [2], med- ical electronics [9], aircraft control [1], and scientific parallel computing [6 a system framework, security overhead, and parallel applications with deadline and security constraintsSecurity-Aware Resource Allocation for Real-Time Parallel Jobs on Homogeneous and Heterogeneous

  16. Multiscale asymptotic homogenization analysis of thermo-diffusive composite materials

    E-Print Network [OSTI]

    A. Bacigalupo; L. Morini; A. Piccolroaz

    2015-03-31T23:59:59.000Z

    In this paper an asymptotic homogenization method for the analysis of composite materials with periodic microstructure in presence of thermodiffusion is described. Appropriate down-scaling relations correlating the microscopic fields to the macroscopic displacements, temperature and mass concentration are introduced. The effects of the material inhomogeneities are described by perturbation functions derived from the solution of recursive cell problems. Exact expressions for the overall elastic and thermodiffusive constants of the equivalent first order thermodiffusive continuum are derived. The proposed approach is applied to the case of a two-dimensional bi-phase orthotropic layered material, where the effective elastic and thermodiffusive properties can be determined analytically. Considering this illustrative example and assuming periodic body forces, heat and mass sources acting on the medium, the solution performed by the first order homogenization approach is compared with the numerical results obtained by the heterogeneous model.

  17. Reliable computation of homogeneous azeotropes

    SciTech Connect (OSTI)

    Maier, R.W.; Brennecke, J.F.; Stadtherr, M.A. [Univ. of Notre Dame, IN (United States). Dept. of Chemical Engineering] [Univ. of Notre Dame, IN (United States). Dept. of Chemical Engineering

    1998-08-01T23:59:59.000Z

    It is important to determine the existence and composition of homogeneous azeotropes in the analysis of phase behavior and in the synthesis and design of separation systems, from both theoretical and practical standpoints. A new method for reliably locating any and all homogeneous azeotropes for multicomponent mixtures is presented. The method also verifies the nonexistence of homogeneous azeotropes if none are present. The method is based on interval analysis, in particular an interval-Newton/generalized-bisection-algorithm providing a mathematical and computational guarantee that all azeotropes are located. This general-purpose technique can be applied in connection with any thermodynamic models. The technique is illustrated in several example problems using the Wilson, NRTL, and UNIQUAC activity-coefficient models.

  18. Applied Catalysis A: General 391 (2011) 342349 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    Goodman, Wayne

    2011-01-01T23:59:59.000Z

    Applied Catalysis A: General 391 (2011) 342­349 Contents lists available at ScienceDirect Applied Catalysis A: General journal homepage: www.elsevier.com/locate/apcata Preparation and characterization of Co in the last several decades due to their practical applications in many industrial areas such as catalysis

  19. Applied Catalysis B: Environmental 29 (2001) 327336 Gas-phase photo-oxidation of toluene using

    E-Print Network [OSTI]

    2001-01-01T23:59:59.000Z

    Applied Catalysis B: Environmental 29 (2001) 327­336 Gas-phase photo-oxidation of toluene using reserved. PII: S0926-3373(00)00211-3 #12;328 A.J. Maira et al. / Applied Catalysis B: Environmental 29.V. All rights reserved. Keywords: Photo-catalysis; Titanium dioxide; Nanoparticles; Volatile organic

  20. Applied Catalysis A: General 477 (2014) 102108 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    Cao, Guozhong

    2014-01-01T23:59:59.000Z

    Applied Catalysis A: General 477 (2014) 102­108 Contents lists available at ScienceDirect Applied Catalysis A: General journal homepage: www.elsevier.com/locate/apcata Ordered mesoporous tungsten carbide, in particular, catalysis [21­24]. A key issue for improving this class of meso- porous structure

  1. Final technical report, Symposium on New Theoretical Concepts and Directions in Catalysis

    SciTech Connect (OSTI)

    Metiu, Horia [University of California, Santa Barbara

    2014-08-22T23:59:59.000Z

    We organized in August 2013 a “Symposium on New Theoretical Concepts and Directions in Catalysis” with the participation of 20 invited distinguished quantum chemists and other researchers who use computations to study catalysis. Symposium website; http://catalysis.cnsi.ucsb.edu/

  2. DOI: 10.1002/ijch.201100102 Single-Molecule Studies of HIV-1 Protease Catalysis

    E-Print Network [OSTI]

    Myong, Sua

    DOI: 10.1002/ijch.201100102 Single-Molecule Studies of HIV-1 Protease Catalysis Enabled by Chemical. Introduction Understanding the chemistry of enzyme catalysis has been an important objective of chemical of the chemistry occurring in the enzyme­substrate complex. The physical organic chemistry of enzyme catalysis

  3. Heterogeneity and Trade

    E-Print Network [OSTI]

    Costinot, Arnaud

    2007-01-01T23:59:59.000Z

    s ), and, because of free trade in …nal goods, factor price2007], Wealth Heterogeneity and Trade, mimeo Uni- versity ofTheory of International Trade, Cambridge University Press. [

  4. Heterogeneous Catalysis on Atomically Dispersed Supported Metals: CO2 Reduction on Multifunctional Pd Catalysts

    SciTech Connect (OSTI)

    Kwak, Ja Hun; Kovarik, Libor; Szanyi, Janos

    2013-11-01T23:59:59.000Z

    Temperature programmed reaction and scanning transmission electron microscopy experiments were applied to prove the requirement of two different catalyst functionalities for the reduction of CO2 with hydrogen on Pd/Al2O3 and Pd/MWCNT catalysts. The research described in this paper was supported by the Laboratory Directed Research and Development (LDRD) program of the Pacific Northwest National Laboratory (PNNL) and was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at PNNL. PNNL is operated for the US DOE by Battelle Memorial Institute.

  5. Computational heterogeneous catalysis applied to steam methane reforming over nickel and nickel/silver catalysts

    E-Print Network [OSTI]

    Blaylock, Donnie Wayne

    2011-01-01T23:59:59.000Z

    The steam methane reforming (SMR) reaction is the primary industrial means for producing hydrogen gas. As such, it is a critical support process for applications including petrochemical processing and ammonia synthesis. ...

  6. Exhaust aftertreatment using plasma-assisted catalysis

    SciTech Connect (OSTI)

    Penetrante, B

    2000-01-20T23:59:59.000Z

    In the field of catalysis, one application that has been classified as a breakthrough technology is the catalytic reduction of NO{sub x} in oxygen-rich environments using hydrocarbons. This breakthrough will require dramatic improvements in both catalyst and engine technology, but the benefits will be substantial for energy efficiency and a cleaner environment. Engine and automobile companies are placing greater emphasis on the diesel engine because of its potential for saving fuel resources and reducing CO{sub 2} emissions. The modern direct-injection diesel engine offers demonstrated fuel economy advantages unmatched by any other commercially-viable engine. The main drawback of diesel engines is exhaust emissions. A modification of existing oxidation catalyst/engine technology is being used to address the CO, hydrocarbon and particulates. However, no satisfactory solution currently exists for NO{sub x}. Diesel engines operate under net oxidizing conditions, thus rendering conventional three-way catalytic converters ineffective for the controlling the NO{sub x} emission. NO{sub x} reduction catalysts, using ammonia as a reductant, do exist for oxygen-rich exhausts; however, for transportation applications, the use of on-board hydrocarbon fuels is a more feasible, cost-effective, and environmentally-sound approach. Selective catalytic reduction (SCR) by hydrocarbons is one of the leading catalytic aftertreatment technologies for the reduction of NO{sub x} in lean-burn engine exhaust (often referred to as lean-NO{sub x}). The objective is to chemically reduce the pollutant molecules of NO{sub x} to benign molecules such as N{sub 2}. Aftertreatment schemes have focused a great deal on the reduction of NO because the NO{sub x} in engine exhaust is composed primarily of NO. Recent studies, however, have shown that the oxidation of NO to NO{sub 2} serves an important role in enhancing the efficiency for reduction of NO{sub x} to N{sub 2}. It has become apparent that preconverting NO to NO{sub 2} could improve both the efficiency and durability of lean-NO{sub x} catalysts. A non-thermal plasma is an efficient means for selective partial oxidation of NO to NO{sub 2}. The use of a non-thermal plasma in combination with a lean-NO{sub x} catalyst opens the opportunity for catalysts that are more efficient and more durable compared to conventional catalysts. In the absence of hydrocarbons, the O radicals will oxidize NO to NO{sub 2}, and the OH radicals will further oxidize NO{sub 2} to nitric acid. In plasma-assisted catalysis it is important that the plasma oxidize NO to NO{sub 2} without further producing acids.

  7. High-Spin Cobalt Hydrides for Catalysis

    SciTech Connect (OSTI)

    Holland, Patrick L. [Yale University] [Yale University

    2013-08-29T23:59:59.000Z

    Organometallic chemists have traditionally used catalysts with strong-field ligands that give low-spin complexes. However, complexes with a weak ligand field have weaker bonds and lower barriers to geometric changes, suggesting that they may lead to more rapid catalytic reactions. Developing our understanding of high-spin complexes requires the use of a broader range of spectroscopic techniques, but has the promise of changing the mechanism and/or selectivity of known catalytic reactions. These changes may enable the more efficient utilization of chemical resources. A special advantage of cobalt and iron catalysts is that the metals are more abundant and cheaper than those currently used for major industrial processes that convert unsaturated organic molecules and biofeedstocks into useful chemicals. This project specifically evaluated the potential of high-spin cobalt complexes for small-molecule reactions for bond rearrangement and cleavage reactions relevant to hydrocarbon transformations. We have learned that many of these reactions proceed through crossing to different spin states: for example, high-spin complexes can flip one electron spin to access a lower-energy reaction pathway for beta-hydride elimination. This reaction enables new, selective olefin isomerization catalysis. The high-spin cobalt complexes also cleave the C-O bond of CO2 and the C-F bonds of fluoroarenes. In each case, the detailed mechanism of the reaction has been determined. Importantly, we have discovered that the cobalt catalysts described here give distinctive selectivities that are better than known catalysts. These selectivities come from a synergy between supporting ligand design and electronic control of the spin-state crossing in the reactions.

  8. Catalysis-by-design impacts assessment

    SciTech Connect (OSTI)

    Fassbender, L L; Young, J K [Pacific Northwest Lab., Richland, WA (USA); Sen, R K [Sen (R.K.) and Associates, Washington, DC (USA)

    1991-05-01T23:59:59.000Z

    Catalyst researchers have always recognized the need to develop a detailed understanding of the mechanisms of catalytic processes, and have hoped that it would lead to developing a theoretical predictive base to guide the search for new catalysts. This understanding allows one to develop a set of hierarchical models, from fundamental atomic-level ab-initio models to detailed engineering simulations of reactor systems, to direct the search for optimized, efficient catalyst systems. During the last two decades, the explosions of advanced surface analysis techniques have helped considerably to develop the building blocks for understanding various catalytic reactions. An effort to couple these theoretical and experimental advances to develop a set of hierarchical models to predict the nature of catalytic materials is a program entitled Catalysis-by-Design (CRD).'' In assessing the potential impacts of CBD on US industry, the key point to remember is that the value of the program lies in developing a novel methodology to search for new catalyst systems. Industrial researchers can then use this methodology to develop proprietary catalysts. Most companies involved in catalyst R D have two types of ongoing projects. The first type, what we call market-driven R D,'' are projects that support and improve upon a company's existing product lines. Project of the second type, technology-driven R D,'' are longer term, involve the development of totally new catalysts, and are initiated through scientists' research ideas. The CBD approach will impact both types of projects. However, this analysis indicates that the near-term impacts will be on market-driven'' projects. The conclusions and recommendations presented in this report were obtained by the authors through personal interviews with individuals involved in a variety of industrial catalyst development programs and through the three CBD workshops held in the summer of 1989. 34 refs., 7 figs., 7 tabs.

  9. Homogeneous Random Measures and Strongly Supermedian Kernels

    E-Print Network [OSTI]

    Fitzsimmons, Patrick J.

    . Keywords and phrases: Homogeneous random measure, additive functional, Kuznets* *ov measure, potential

  10. Joint Center for Artificial Photosynthesis

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

    Heterogeneous Catalysis heterogeneous catalysis The focus of the Heterogeneous Catalysis project is to discover and develop heterogeneous catalysts for solar-fuel generation. Using...

  11. Dedicated heterogeneous node scheduling including backfill scheduling

    DOE Patents [OSTI]

    Wood, Robert R. (Livermore, CA); Eckert, Philip D. (Livermore, CA); Hommes, Gregg (Pleasanton, CA)

    2006-07-25T23:59:59.000Z

    A method and system for job backfill scheduling dedicated heterogeneous nodes in a multi-node computing environment. Heterogeneous nodes are grouped into homogeneous node sub-pools. For each sub-pool, a free node schedule (FNS) is created so that the number of to chart the free nodes over time. For each prioritized job, using the FNS of sub-pools having nodes useable by a particular job, to determine the earliest time range (ETR) capable of running the job. Once determined for a particular job, scheduling the job to run in that ETR. If the ETR determined for a lower priority job (LPJ) has a start time earlier than a higher priority job (HPJ), then the LPJ is scheduled in that ETR if it would not disturb the anticipated start times of any HPJ previously scheduled for a future time. Thus, efficient utilization and throughput of such computing environments may be increased by utilizing resources otherwise remaining idle.

  12. Enantioselective Alkenylation of Aldehydes with Boronic Acids via the Synergistic Combination of Copper(II) and Amine Catalysis

    E-Print Network [OSTI]

    MacMillan, David W. C.

    recently applied the synergistic catalysis paradigm to the development of several new asymmetric bond of Copper(II) and Amine Catalysis Jason M. Stevens and David W. C. MacMillan* Merck Center for Catalysis combination of copper and chiral amine catalysis. The merger of two highly utilized and robust catalytic

  13. MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

    SciTech Connect (OSTI)

    Burt, Scott R; Burt, Scott R.

    2008-06-25T23:59:59.000Z

    The power of magnetic resonance imaging (MRI) is its ability to image the internal structure of optically opaque samples and provide detailed maps of a variety of important parameters, such as density, diffusion, velocity and temperature. However, one of the fundamental limitations of this technique is its inherent low sensitivity. For example, the low signal to noise ratio (SNR) is particularly problematic for imaging gases in porous materials due to the low density of the gas and the large volume occluded by the porous material. This is unfortunate, as many industrially relevant chemical reactions take place at gas-surface interfaces in porous media, such as packed catalyst beds. Because of this severe SNR problem, many techniques have been developed to directly increase the signal strength. These techniques work by manipulating the nuclear spin populations to produce polarized} (i.e., non-equilibrium) states with resulting signal strengths that are orders of magnitude larger than those available at thermal equilibrium. This dissertation is concerned with an extension of a polarization technique based on the properties of parahydrogen. Specifically, I report on the novel use of heterogeneous catalysis to produce parahydrogen induced polarization and applications of this new technique to gas phase MRI and the characterization of micro-reactors. First, I provide an overview of nuclear magnetic resonance (NMR) and how parahydrogen is used to improve the SNR of the NMR signal. I then present experimental results demonstrating that it is possible to use heterogeneous catalysis to produce parahydrogen-induced polarization. These results are extended to imaging void spaces using a parahydrogen polarized gas. In the second half of this dissertation, I demonstrate the use of parahydrogen-polarized gas-phase MRI for characterizing catalytic microreactors. Specifically, I show how the improved SNR allows one to map parameters important for characterizing the heat and mass transport in a heterogeneous catalyst bed. This is followed by appendices containing detailed information regarding the design and use of my experimental setup.

  14. Allylation of acetanilides with allyl acetate under conditions of metal-complex catalysis combined with phase-transfer catalysis

    SciTech Connect (OSTI)

    Lebedev, S.A.; Leonova, Yu.P.; Berestova, S.S.; Petrov, E.S.

    1988-10-20T23:59:59.000Z

    Acetanilides are alkylated at the nitrogen atom under the conditions of phase-transfer catalysis. For the case of the reaction of acetanilides with allyl acetate the authors showed that 2-alkenyl esters can be used for the alkylation of acetanilides under the conditions of phase-transfer catalysis in the presence of the complexes of zero valent palladium. N-Acetylskatole was obtained with a yield of 50% from N-allyl-2-bromoacetanilide by intramolecular cyclization in the presence of Od(OAc)/sub 2/ as catalyst.

  15. Frontiers in Catalysis Science and Engineering Seminar Series

    E-Print Network [OSTI]

    in internal combustion engines and power plants. Copper-exchanged promising as selective catalytic reduction ) are a major atmospheric pollutant produced through the combustion of fossil fuels in internal combustionFrontiers in Catalysis Science and Engineering Seminar Series Small Pore Zeolites: Effective

  16. Frontiers in Catalysis Science and Engineering Seminar Series

    E-Print Network [OSTI]

    Frontiers in Catalysis Science and Engineering Seminar Series On the role of hydrogen of Chemical & Biological Engineering ·University of Wisconsin - Madison Abstract Hydrogen is a frequent principles governing the role of hydrogen in a wide range of catalytic transformations begin to emerge

  17. Overview of surface science and catalysis by Qifei Wu

    E-Print Network [OSTI]

    of hydrodesulfurization catalysis Crude oil contains S-impurity (R-S; environmental hazard) H2 + R-S RH + H2S catalyst P. Hydrodesulfurization (HDS) on metcar nanoparticles C4H4S(g) +3H2(g) C4H8(g) +H2S(g) According to our DFT calculations

  18. Lithium Diisopropylamide-Mediated Ortholithiations: Lithium Chloride Catalysis

    E-Print Network [OSTI]

    Collum, David B.

    Lithium Diisopropylamide-Mediated Ortholithiations: Lithium Chloride Catalysis Lekha Gupta, 2008 Ortholithiations of a range of arenes mediated by lithium diisopropylamide (LDA) in THF at -78 °C protocols with unpurified commercial samples of n-butyl- lithium to prepare LDA or commercially available

  19. JOURNAL OF CATALYSIS 177, 343351 (1998) ARTICLE NO. CA982143

    E-Print Network [OSTI]

    Iglesia, Enrique

    1998-01-01T23:59:59.000Z

    - modynamically favorable at high temperatures, but often leads to high yields of coke and smaller hydrocarbons, but it requires a selective catalyst in order to avoid complete oxidation to CO and CO2. A number of recentJOURNAL OF CATALYSIS 177, 343­351 (1998) ARTICLE NO. CA982143 Structure and Properties of Vanadium

  20. Heterogeneous recurrence monitoring and control of nonlinear stochastic processes

    SciTech Connect (OSTI)

    Yang, Hui, E-mail: huiyang@usf.edu; Chen, Yun [Complex Systems Monitoring, Modeling and Analysis Laboratory, University of South Florida, Tampa, Florida 33620 (United States)] [Complex Systems Monitoring, Modeling and Analysis Laboratory, University of South Florida, Tampa, Florida 33620 (United States)

    2014-03-15T23:59:59.000Z

    Recurrence is one of the most common phenomena in natural and engineering systems. Process monitoring of dynamic transitions in nonlinear and nonstationary systems is more concerned with aperiodic recurrences and recurrence variations. However, little has been done to investigate the heterogeneous recurrence variations and link with the objectives of process monitoring and anomaly detection. Notably, nonlinear recurrence methodologies are based on homogeneous recurrences, which treat all recurrence states in the same way as black dots, and non-recurrence is white in recurrence plots. Heterogeneous recurrences are more concerned about the variations of recurrence states in terms of state properties (e.g., values and relative locations) and the evolving dynamics (e.g., sequential state transitions). This paper presents a novel approach of heterogeneous recurrence analysis that utilizes a new fractal representation to delineate heterogeneous recurrence states in multiple scales, including the recurrences of both single states and multi-state sequences. Further, we developed a new set of heterogeneous recurrence quantifiers that are extracted from fractal representation in the transformed space. To that end, we integrated multivariate statistical control charts with heterogeneous recurrence analysis to simultaneously monitor two or more related quantifiers. Experimental results on nonlinear stochastic processes show that the proposed approach not only captures heterogeneous recurrence patterns in the fractal representation but also effectively monitors the changes in the dynamics of a complex system.

  1. Superization of Homogeneous Spin Manifolds and Geometry of Homogeneous Supermanifolds

    E-Print Network [OSTI]

    Andrea Santi

    2009-05-24T23:59:59.000Z

    Let M_0=G_0/H be a (pseudo)-Riemannian homogeneous spin manifold, with reductive decomposition g_0=h+m and let S(M_0) be the spin bundle defined by the spin representation Ad:H->\\GL_R(S) of the stabilizer H. This article studies the superizations of M_0, i.e. its extensions to a homogeneous supermanifold M=G/H whose sheaf of superfunctions is isomorphic to Lambda(S^*(M_0)). Here G is the Lie supergroup associated with a certain extension of the Lie algebra of symmetry g_0 to an algebra of supersymmetry g=g_0+g_1=g_0+S via the Kostant-Koszul construction. Each algebra of supersymmetry naturally determines a flat connection nabla^{S} in the spin bundle S(M_0). Killing vectors together with generalized Killing spinors (i.e. nabla^{S}-parallel spinors) are interpreted as the values of appropriate geometric symmetries of M, namely even and odd Killing fields. An explicit formula for the Killing representation of the algebra of supersymmetry is obtained, generalizing some results of Koszul. The generalized spin connection nabla^{S} defines a superconnection on M, via the super-version of a theorem of Wang.

  2. NOTE: OPTIMAL NON-HOMOGENEOUS COMPOSITES FOR ...

    E-Print Network [OSTI]

    R. Tavakoli

    2012-10-02T23:59:59.000Z

    NOTE: OPTIMAL NON-HOMOGENEOUS COMPOSITES FOR. DYNAMIC LOADING REVISITED. R. TAVAKOLI. 1. Problem formulation. Consider ? ? Rd (

  3. Catalysis Center for Energy Innovation for Biomass Processing: Research Strategies and Goals

    SciTech Connect (OSTI)

    Vlachos, Dion G.; Chen, Jingguang; Gorte, R. J.; Huber, George W.; Tsapatsis, Michael

    2010-01-01T23:59:59.000Z

    Production of energy and chemicals from biomass is of critical importance in meeting some of the challenges associated with decreasing availability of fossil fuels and addressing global climate change. In the current article, we outline a perspective on key challenges of biomass processing. We also introduce the Catalysis Center for Energy Innovation (CCEI), one of the 46 Energy Frontier Research Centers established by the Department of Energy in the spring of 2009, and CCEI’s overall research strategies and goals along with its cross-cutting research thrusts that can enable potential technological breakthroughs in the utilization of biomass and its derivatives. The center focuses on developing innovative heterogeneous catalysts and processing schemes that can lead to viable biorefineries for the conversion of biomass to chemicals, fuels, and electricity. In order to achieve this goal, a group of over twenty faculty members from nine institutions has been assembled to bring together complementary expertise covering novel materials synthesis, advanced characterization, multiscale modeling, surface science, catalytic kinetics, and microreactors.

  4. Heterogeneous electrocatalysis in porous cathodes of solid oxide fuel cells

    E-Print Network [OSTI]

    Fu, Y; Bertei, A; Qi, C; Mohanram, A; Pietras, J D; Bazant, M Z

    2014-01-01T23:59:59.000Z

    A general physics-based model is developed for heterogeneous electrocatalysis in porous electrodes and used to predict and interpret the impedance of solid oxide fuel cells. This model describes the coupled processes of oxygen gas dissociative adsorption and surface diffusion of the oxygen intermediate to the triple phase boundary, where charge transfer occurs. The model accurately captures the Gerischer-like frequency dependence and the oxygen partial pressure dependence of the impedance of symmetric cathode cells. Digital image analysis of the microstructure of the cathode functional layer in four different cells directly confirms the predicted connection between geometrical properties and the impedance response. As in classical catalysis, the electrocatalytic activity is controlled by an effective Thiele modulus, which is the ratio of the surface diffusion length (mean distance from an adsorption site to the triple phase boundary) to the surface boundary layer length (square root of surface diffusivity div...

  5. One- and two-dimensional infrared spectroscopic studies of solution-phase homogeneous catalysis and spin-forbidden reactions

    SciTech Connect (OSTI)

    Sawyer, Karma Rae

    2008-12-12T23:59:59.000Z

    Understanding chemical reactions requires the knowledge of the elementary steps of breaking and making bonds, and often a variety of experimental techniques are needed to achieve this goal. The initial steps occur on the femto- through picosecond time-scales, requiring the use of ultrafast spectroscopic methods, while the rate-limiting steps often occur more slowly, requiring alternative techniques. Ultrafast one and two-dimensional infrared and step-scan FTIR spectroscopies are used to investigate the photochemical reactions of four organometallic complexes. The analysis leads to a detailed understanding of mechanisms that are general in nature and may be applicable to a variety of reactions.

  6. One- and two-dimensional infrared spectroscopic studies of solution-phase homogeneous catalysis and spin-forbidden reactions

    E-Print Network [OSTI]

    Sawyer, Karma Rae

    2010-01-01T23:59:59.000Z

    Tsunami 80 MHz, 650 mW, 80 fs, 800 nm (FWHM = 13nm) Nd:YLF nanosecond pump laser SpectraPhysics Evolution-

  7. Journal of Molecular Catalysis A: Chemical 251 (2006) 823 Design and study of homogeneous catalysts for the selective,

    E-Print Network [OSTI]

    Goddard III, William A.

    2006-01-01T23:59:59.000Z

    as groups have focused on the catalytic conversion of its major component, methane, to functionalized products. The key requirements is to design new catalysts for the oxidative functionalization of methane oxidation chemistry could lead to a new paradigm in petrochemical technology that is environmentally cleaner

  8. Plasma-Activated Lean NOx Catalysis for Heavy-Duty Diesel Emissions...

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

    2002deeraardahl.pdf More Documents & Publications Heavy-Duty NOx Emissions Control: Reformer-Assisted vs. Plasma-Facilitated Lean NOx Catalysis Selective reduction of NOx in...

  9. Support for U.S. Participants at the 15th International Congress on Catalysis

    SciTech Connect (OSTI)

    Wachs, Israel E.

    2013-08-05T23:59:59.000Z

    The grant was used to partially assist the travel expenses of U.S. academic scientists to attend the 15th International Congress on Catalysis. The conference was held in Munich, Germany from July 1-6, 2012. The importance of the International Congress was to bring together the international community of faculty members who participate in catalysis research, and to share information that would lead to further developments and directions in the field of study. Graduate students and Post Docs were invited to apply for travel assistance based on criteria established by the North American Catalysis Society (NACS) and the local Catalysis Clubs.

  10. Plasma-Activated Lean NOx Catalysis for Heavy-Duty Diesel Emissions...

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

    Lean NOx Catalysis l Chemistry l Reducing Agent Effects l Collaboration with LEP CRADA l Aging Studies Plasma Initiation - + Electron Avalanche e - e - e - e - e - e - e -...

  11. Isolated Palladium Atoms Allow Highly-Selective Catalysis of...

    Office of Science (SC) Website

    a general strategy for designing novel bifunctional heterogeneous catalysts for the production of fuels, agricultural chemicals and medicine. By controlling changes to the amount...

  12. A novel bifunctional catalyst for alkene isomerization : development, scope and limitations, and applications in organic transformations

    E-Print Network [OSTI]

    Larsen, Casey Renee

    2012-01-01T23:59:59.000Z

    W. A. Applied Homogenous Catalysis with OrganometallicW. A. Applied Homogenous Catalysis with OrganometallicIndustry” Applied Homogenous Catalysis with Organometallic

  13. Heterogeneous waste processing

    DOE Patents [OSTI]

    Vanderberg, Laura A. (Los Alamos, NM); Sauer, Nancy N. (Los Alamos, NM); Brainard, James R. (Los Alamos, NM); Foreman, Trudi M. (Los Alamos, NM); Hanners, John L. (Los Alamos, NM)

    2000-01-01T23:59:59.000Z

    A combination of treatment methods are provided for treatment of heterogeneous waste including: (1) treatment for any organic compounds present; (2) removal of metals from the waste; and, (3) bulk volume reduction, with at least two of the three treatment methods employed and all three treatment methods emplyed where suitable.

  14. Applied Catalysis A: General 232 (2002) 219235 An EXAFS study of the co-ordination chemistry of hydrogen

    E-Print Network [OSTI]

    Regalbuto, John R.

    2002-01-01T23:59:59.000Z

    Applied Catalysis A: General 232 (2002) 219­235 An EXAFS study of the co-ordination chemistry)00116-3 #12;220 W.A. Spieker et al. / Applied Catalysis A: General 232 (2002) 219­235 dissociation

  15. Low-Temperature Hydrocarbon/CO Oxidation Catalysis in Support...

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

    Development of catalyst materials to facilitate the low-temperature oxidation of hydrocarbons and CO in homogeneous charge compression ignition (HCCI) emissions. deer08...

  16. The research at the department of Biochemistry is focused on enzyme catalysis, applied enzymology and ecological plant biochemistry. There are two main activities within enzyme catalysis, one towards synthesis

    E-Print Network [OSTI]

    Lagergren, Jens

    The research at the department of Biochemistry is focused on enzyme catalysis, applied enzymology and ecological plant biochemistry. There are two main activities within enzyme catalysis, one towards synthesis of enzyme catalysis based on a broad interdisciplinary competence in enzymology, molecular biology, organic

  17. Optimization Online - On Implementing a Homogeneous Interior ...

    E-Print Network [OSTI]

    Anders Skajaa

    2011-01-25T23:59:59.000Z

    Jan 25, 2011 ... imm.dtu.dk) Per Christian Hansen (pch ***at*** imm.dtu.dk). Abstract: Based on earlier work by Nesterov, an implementation of a homogeneous ...

  18. Probing the chemistry of thioredoxin catalysis Arun P. Wiita1,2

    E-Print Network [OSTI]

    Fernandez, Julio M.

    LETTERS Probing the chemistry of thioredoxin catalysis with force Arun P. Wiita1,2 , Raul Perez organisms1 . Although catalysis is thought to proceed through a substitution nucleophilic bimolecular (SN2 (Trx). We applied mechanical force in the range of 25­600 pN to a disulphide bond substrate

  19. Advanced Synthesis & Catalysis Terminal alkyne metathesis: a further step towards selectivity.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Advanced Synthesis & Catalysis Terminal alkyne metathesis: a further step towards selectivity 320436585 E-mail: andre.mortreux@ensc-lille.fr , Received alkyne / metathesis / catalysis / carbyne,[2] the latter giving rise to much more active catalysts, allowing the reaction to be applied

  20. Amine a-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway

    E-Print Network [OSTI]

    MacMillan, David W. C.

    Amine a-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway accomplished via photoredox catalysis to generate valuable benzylic amine pharmacophores. A variety of five substitution (SNAr)3 or transi- tion metal-catalyzed approaches,4 have been extensively studied and applied

  1. Applied Catalysis A: General 226 (2002) 183192 NO reduction by urea under lean conditions

    E-Print Network [OSTI]

    Gulari, Erdogan

    2002-01-01T23:59:59.000Z

    Applied Catalysis A: General 226 (2002) 183­192 NO reduction by urea under lean conditions over.V. All rights reserved. PII: S0926-860X(01)00901-2 #12;184 E. Seker et al. / Applied Catalysis A: General

  2. Journal of Catalysis 260 (2008) 342350 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    Regalbuto, John R.

    2008-01-01T23:59:59.000Z

    Journal of Catalysis 260 (2008) 342­350 Contents lists available at ScienceDirect Journal of Catalysis www.elsevier.com/locate/jcat The synthesis of highly dispersed noble and base metals on silica via The catalyst synthesis method of strong electrostatic adsorption (SEA) was applied to mesoporous silica SBA-15

  3. Journal of Catalysis 260 (2008) 329341 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    Regalbuto, John R.

    2008-01-01T23:59:59.000Z

    Journal of Catalysis 260 (2008) 329­341 Contents lists available at ScienceDirect Journal of Catalysis www.elsevier.com/locate/jcat The synthesis of highly dispersed noble and base metals on silica via and after reduction. The results showed that the SEA method can be applied for many ammine complexes

  4. Z .Journal of Molecular Catalysis A: Chemical 153 2000 155163 www.elsevier.comrlocatermolcata

    E-Print Network [OSTI]

    Truong, Thanh N.

    Z .Journal of Molecular Catalysis A: Chemical 153 2000 155­163 www and Applied Chemistry, Chemistry Department, Faculty of Science, Kasetsart UniÕersity, Bangkok 10900, Thailand. q 2000 Elsevier Science B.V. All rights reserved. 1. Introduction Zeolite catalysis is of prime

  5. Bifunctional Lewis Acid-Nucleophile-Based Asymmetric Catalysis: Mechanistic Evidence for Imine Activation Working

    E-Print Network [OSTI]

    Lectka, Thomas

    Bifunctional Lewis Acid-Nucleophile-Based Asymmetric Catalysis: Mechanistic Evidence for Imine that substantial progress has been made in the use of well- defined bifunctional systems as applied to asymmetric catalysis.4 Several of these systems combine a metal ion (usually as part of a chiral Lewis acid complex

  6. Tandem Catalysis A Highly Efficient and Rapid Approach to Synthetic Elaboration

    E-Print Network [OSTI]

    Stoltz, Brian M.

    diiodide catalyzed Mukaiyama Michael-aldol reactions C.) Zirconium catalyzed synthesis of !-cyanohydrins D and rhodium catalyzed annulation. B.) Cobalt catalyzed annulation and cycloaddition C.) Rapid synthesis of pyrroles and furans D.) Organocatalytic / Lewis acid tandem catalysis 5.) Conclusions Tandem catalysis

  7. AQUEOUS HOMOGENEOUS REACTORTECHNICAL PANEL REPORT

    SciTech Connect (OSTI)

    Diamond, D.J.; Bajorek, S.; Bakel, A.; Flanagan, G.; Mubayi, V.; Skarda, R.; Staudenmeier, J.; Taiwo, T.; Tonoike, K.; Tripp, C.; Wei, T.; Yarsky, P.

    2010-12-03T23:59:59.000Z

    Considerable interest has been expressed for developing a stable U.S. production capacity for medical isotopes and particularly for molybdenum- 99 (99Mo). This is motivated by recent re-ductions in production and supply worldwide. Consistent with U.S. nonproliferation objectives, any new production capability should not use highly enriched uranium fuel or targets. Conse-quently, Aqueous Homogeneous Reactors (AHRs) are under consideration for potential 99Mo production using low-enriched uranium. Although the Nuclear Regulatory Commission (NRC) has guidance to facilitate the licensing process for non-power reactors, that guidance is focused on reactors with fixed, solid fuel and hence, not applicable to an AHR. A panel was convened to study the technical issues associated with normal operation and potential transients and accidents of an AHR that might be designed for isotope production. The panel has produced the requisite AHR licensing guidance for three chapters that exist now for non-power reactor licensing: Reac-tor Description, Reactor Coolant Systems, and Accident Analysis. The guidance is in two parts for each chapter: 1) standard format and content a licensee would use and 2) the standard review plan the NRC staff would use. This guidance takes into account the unique features of an AHR such as the fuel being in solution; the fission product barriers being the vessel and attached systems; the production and release of radiolytic and fission product gases and their impact on operations and their control by a gas management system; and the movement of fuel into and out of the reactor vessel.

  8. THE KINEMATIC FORMULA IN RIEMANNIAN HOMOGENEOUS SPACES

    E-Print Network [OSTI]

    Howard, Ralph

    THE KINEMATIC FORMULA IN RIEMANNIAN HOMOGENEOUS SPACES Ralph Howard Department of Mathematics)IR (N). This generalizes the Chern-Federer kinematic formula to arbitrary homogeneous spaces with an invariant Riemannian metric and leads to new formulas even in the case of submanifolds of Euclidean space

  9. ADSORPTION OF SEMIFLEXIBLE POLYMERS ON HOMOGENEOUS SURFACES

    E-Print Network [OSTI]

    Oro, Daniel

    ADSORPTION OF SEMIFLEXIBLE POLYMERS ON HOMOGENEOUS SURFACES K. Sumithra F G Theoretische Physik the problem of adsorption of a single semiflexible polymer chain on to a planar, homogeneous surface using off-lattice Monte Carlosimulations. Adsorption characteristics were studied at different temperatures for chains

  10. Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

    SciTech Connect (OSTI)

    Coble, Inger M

    2008-08-15T23:59:59.000Z

    Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.

  11. Inorganic Chemistry in Hydrogen Storage and Biomass Catalysis

    SciTech Connect (OSTI)

    Thorn, David [Los Alamos National Laboratory

    2012-06-13T23:59:59.000Z

    Making or breaking C-H, B-H, C-C bonds has been at the core of catalysis for many years. Making or breaking these bonds to store or recover energy presents us with fresh challenges, including how to catalyze these transformations in molecular systems that are 'tuned' to minimize energy loss and in molecular and material systems present in biomass. This talk will discuss some challenging transformations in chemical hydrogen storage, and some aspects of the inorganic chemistry we are studying in the development of catalysts for biomass utilization.

  12. Catalysis Science | U.S. DOE Office of Science (SC)

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z C o . C lKieling ,Catalysis Science Chemical

  13. Theoretical Study on Catalysis by Protein Enzymes and Ribozyme

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin Transition in theTheoretical Study on Catalysis by Protein Enzymes

  14. Catalysis Working Group Meeting: June 2014 | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: Theof Energy Change RequestFirstchampions, checklists,CaseyCatalysis Working

  15. Catalysis Working Group Meeting: May 2013 | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: Theof Energy Change RequestFirstchampions, checklists,CaseyCatalysis

  16. Catalysis by Design - Theoretical and Experimental Studies of Model

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels DataDepartment of Energy Your Density Isn't Your Destiny: Theof Energy Change RequestFirstchampions, checklists,CaseyCatalysisCatalysts

  17. Catalysis | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurTheBrookhaven National Laboratory Laboratory Policy (LP) LPCMSNFScienceCatalysis

  18. TRANSPORT IN HETEROGENEOUS

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    ; HOMOGENEOUS MEDIUM Flow: Darcy Equation u(x) = Krh(x) Incompressibility: r #1; u(x) = 0 Boundary Conditions Field: Darcy Equation u(x) = exp(f(x)) rh(x) Incompressibility r #1; u(x) = 0 Assumption: f(x) = f f 0), and autocorrelation function f 0 (x) f 0 (x 0 ) = C ff (x x 0 ) Via the Darcy equation the randomness transfers to u

  19. Reaction Pathways for Oxygen Evolution Promoted by Cobalt Giuseppe Mattioli,*,

    E-Print Network [OSTI]

    Guidoni, Leonardo

    ABSTRACT: The in-depth understanding of the molecular mechanisms regulating the water oxidation catalysis heterogeneous and homogeneous TM-based oxygen evolving catalysts,5 containing different metal-oxygen cores (Mn,6

  20. MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

    E-Print Network [OSTI]

    Burt, Scott R

    2008-01-01T23:59:59.000Z

    Gas–liquid–solid Catalytic Fixed Bed Reactor. ChemicalConversion Within a Fixed- bed Reactor. Applied Catalysis A:

  1. Campagne d'emplois enseignants-chercheurs 2014 UPMC -Universit Pierre et Marie Curie -Sorbonne Universits

    E-Print Network [OSTI]

    Arleo, Angelo

    EURAXESS RESEARCH FIELDS Engineering Chemical engineering Chemistry Heterogeneous catalysis ENSEIGNEMENT

  2. Multiscale strength homogenization : application to shale nanoindentation

    E-Print Network [OSTI]

    Gathier, Benjamin

    2008-01-01T23:59:59.000Z

    Shales are one of the most encountered materials in sedimentary basins. Because of their highly heterogeneous nature, their strength prediction for oil and gas exploitation engineering has long time been an enigma. In this ...

  3. Producing tritium in a homogenous reactor

    DOE Patents [OSTI]

    Cawley, William E. (Richland, WA)

    1985-01-01T23:59:59.000Z

    A method and apparatus are described for the joint production and separation of tritium. Tritium is produced in an aqueous homogenous reactor and heat from the nuclear reaction is used to distill tritium from the lower isotopes of hydrogen.

  4. 1 Electrospun Polyethylene Oxide/Cellulose Nanocrystal Composite 2 Nanofibrous Mats with Homogeneous and Heterogeneous

    E-Print Network [OSTI]

    property, and excellent flexibility for 32 chemical/physical surface functionalization. Hence, electrospun nanoparticles into polymer matrices is one 47 technique that has been developed and used as one of the most 48(acrylic acid) (PAA),14 polyethylene oxide (PEO),15 poly(lactic 57acid) (PLA),16,17 polystyrene (PS),18

  5. Untangling the Chemical Evolution of Titan's Atmosphere and Surface -- From Homogeneous to Heterogeneous Chemistry

    SciTech Connect (OSTI)

    Kaiser, Ralf I.; Maksyutenko, Pavlo; Ennis, Courtney; Zhang, Fangtong; Gu, Xibin; Krishtal, Sergey P.; Mebel, Alexander M.; Kostko, Oleg; Ahmed, Musahid

    2010-03-16T23:59:59.000Z

    The arrival of the Cassini-Huygens probe at Saturn's moon Titan - the only Solar System body besides Earth and Venus with a solid surface and a thick atmosphere with a pressure of 1.4 atm at surface level - in 2004 opened up a new chapter in the history of Solar System exploration. The mission revealed Titan as a world with striking Earth-like landscapes involving hydrocarbon lakes and seas as well as sand dunes and lava-like features interspersed with craters and icy mountains of hitherto unknown chemical composition. The discovery of a dynamic atmosphere and active weather system illustrates further the similarities between Titan and Earth. The aerosol-based haze layers, which give Titan its orange-brownish color, are not only Titan's most prominent optically visible features, but also play a crucial role in determining Titan's thermal structure and chemistry. These smog-like haze layers are thought to be very similar to those that were present in Earth's atmosphere before life developed more than 3.8 billion years ago, absorbing the destructive ultraviolet radiation from the Sun, thus acting as 'prebiotic ozone' to preserve astrobiologically important molecules on Titan. Compared to Earth, Titan's low surface temperature of 94 K and the absence of liquid water preclude the evolution of biological chemistry as we know it. Exactly because of these low temperatures, Titan provides us with a unique prebiotic 'atmospheric laboratory' yielding vital clues - at the frozen stage - on the likely chemical composition of the atmosphere of the primitive Earth. However, the underlying chemical processes, which initiate the haze formation from simple molecules, have been not understood well to date.

  6. Untangling the Chemical Evolution of Titan's Atmosphere and Surface -- From Homogeneous to Heterogeneous Chemistry

    E-Print Network [OSTI]

    Kaiser, Ralf I.

    2010-01-01T23:59:59.000Z

    infrared spectrum of the irradiated propane ice after heatinginfrared spectrum obtained for irradiated propane ices after controlled heatingsubstrate after heating to 300 K. The infrared spectrum

  7. Ionization of large homogeneous and heterogeneous clusters generated in acetylene-Ar expansions: Cluster ion polymerization

    SciTech Connect (OSTI)

    Kocisek, J.; Lengyel, J.; Farnik, M. [J. Heyrovsky Institute of Physical Chemistry v.v.i., Academy of Sciences of the Czech Republic, Dolejskova 3, 18223 Prague (Czech Republic)

    2013-03-28T23:59:59.000Z

    Pure acetylene and mixed Ar-acetylene clusters are formed in supersonic expansions of acetylene/argon mixtures and analysed using reflectron time-of-flight mass spectrometer with variable electron energy ionization source. Acetylene clusters composed of more than a hundred acetylene molecules are generated at the acetylene concentration of Almost-Equal-To 8%, while mixed species are produced at low concentrations ( Almost-Equal-To 0.7%). The electron energy dependence of the mass spectra revealed the ionization process mechanisms in clusters. The ionization above the threshold for acetylene molecule of 11.5 eV results in the main ionic fragment progression (C{sub 2}H{sub 2}){sub n}{sup +}. At the electron energies Greater-Than-Or-Slanted-Equal-To 21.5 eV above the CH+CH{sup +} dissociative ionization limit of acetylene the fragment ions nominally labelled as (C{sub 2}H{sub 2}){sub n}CH{sup +}, n Greater-Than-Or-Slanted-Equal-To 2, are observed. For n Less-Than-Or-Slanted-Equal-To 7 these fragments correspond to covalently bound ionic structures as suggested by the observed strong dehydrogenation [(C{sub 2}H{sub 2}){sub n}-k Multiplication-Sign H]{sup +} and [(C{sub 2}H{sub 2}){sub n}CH -k Multiplication-Sign H]{sup +}. The dehydrogenation is significantly reduced in the mixed clusters where evaporation of Ar instead of hydrogen can stabilize the nascent molecular ion. The C{sub 3}H{sub 3}{sup +} ion was previously assigned to originate from the benzene molecular ion; however, the low appearance energy of Almost-Equal-To 13.7 eV indicates that a less rigid covalently bound structure of C{sub 6}H{sub 6}{sup +} ion must also be formed upon the acetylene cluster electron ionization. The appearance energy of Ar{sub n}(C{sub 2}H{sub 2}){sup +} fragments above Almost-Equal-To 15.1 eV indicates that the argon ionization is the first step in the fragment ion production, and the appearance energy of Ar{sub n{>=}2}(C{sub 2}H{sub 2}){sub m{>=}2}{sup +} at Almost-Equal-To 13.7 eV is discussed in terms of an exciton transfer mechanism.

  8. Spontaneous generation of local CP violation and inverse magnetic catalysis

    E-Print Network [OSTI]

    Lang Yu; Hao Liu; Mei Huang

    2014-09-14T23:59:59.000Z

    In the chiral symmetric phase, the polarized instanton--anti-instanton molecule pairing induces a nontrivial repulsive interaction in the iso-scalar axial-vector channel. As a consequence, one unusual property is observed that in the chiral restoration phase, there is a first order phase transition for the spontaneous generation of local CP violation and chiral imbalance. Furthermore, it is found that external magnetic fields will lower the critical temperature for the local CP-odd phase transition and catalyze the chiral imbalance, which destroys the chiral condensate with pairing quarks between different chiralities. A reasonable strength of the repulsive interaction in the iso-scalar axial-vector channel can naturally explain the inverse magnetic catalysis around the critical temperature under external magnetic fields.

  9. Metal Carbonyl-Hydrosilane Reactions and Hydrosilation Catalysis

    SciTech Connect (OSTI)

    Cutler, A. R.

    2001-04-14T23:59:59.000Z

    Manganese carbonyl complexes serve as hydrosilation precatalysts for selectively transforming a carbonyl group into a siloxy methylene or a fully reduced methylene group. Substrates of interest include (1) aldehydes, ketones, carboxylic acids, silyl esters, and esters, and (2) their organometallic acyl counterparts. Three relevant catalytic reactions are shown. Two types of manganese precatalysts have been reported: (a) alkyl and acyl complexes (L)(C0){sub 4}MnR [L = CO, PPh{sub 3}; R = COCH{sub 3}, COPh, CH{sub 3}] and (b) halides (CO){sub 5}MnX and [(CO){sub 4}MnX]{sub 2} (X = Br, I). The former promote hydrosilation and deoxygenation catalysis; the latter promote dehydrogenative silation of alcohols and carboxylic acids as well as hydrosilation and deoxygenation of some metallocarboxylic acid derivatives. In every case studied, these Mn precatalysts are far more reactive or selective than traditional Rh(I) precatalysts.

  10. An experimental investigation of viscous fingering in heterogeneous porous media

    SciTech Connect (OSTI)

    Brock, D.C.

    1991-01-01T23:59:59.000Z

    The growth of viscous fingers in heterogeneous porous media was examined using flow visualization experiments in four different glass bead packs with different permeability heterogeneities: a uniform permeability model, one with two equal-width layers in the flow direction, one with a thin, high permeability streak in the flow direction, and one with blocks of different permeabilities. The experiments were compared with numerical simulations, paying particular attention to finger growth mechanisms, finger sizes and locations, and number of fingers. In near-homogeneous model displacements, fingers were observed to grow through the mechanisms of spreading, splitting, shielding, and coalescence. In all experiments, shielding and coalescence acted to reduce the number of fingers as flow progressed. Analysis of pressure distributions in and around fingers indicates that viscous crossflow was the driving force for the finger growth mechanisms. Simulations of the experiments yielded finger patterns similar to those observed in the experiments. The general agreement over a variety of mobility ratios and rates indicates that the simulator used captures the essential features of the physics of finger growth. In heterogeneous permeability fields, locations of fingers were largely determined by the pattern of heterogeneity. In the model with two thick layers and the model with blocks of different permeabilities, a pattern of viscous fingers was superimposed on the fronts. The model with a thin, high permeability streak showed very little viscous fingering because the width of the layer was small. In the heterogeneous cases, simulations yielded finger patterns remarkably similar to those observed in experiments. In particular, simulations reproduced the concept of viscous fingers overlain on flow affected by permeability heterogeneity.

  11. Studies toward biomimetic claisen condensation using nucleic acid templates and ribozyme catalysis

    E-Print Network [OSTI]

    Ryu, Youngha

    2005-08-29T23:59:59.000Z

    Many different experimental approaches were attempted to achieve carbon-carbon bond formation by nucleic acid template-directed reactions and ribozyme catalysis as potential lipid synthesizing machineries in the RNA world. A novel biomimetic...

  12. Two-Stage Plasma-Catalysis for Diesel NOx Emission Control. ...

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

    producing nitrogen. Citation: Hoard J, and RG Tonkyn.2003."Two-Stage Plasma-Catalysis for Diesel NOx Emission Control."Journal of Advanced Oxidation Technologies 6(2):158-165....

  13. Molecular computations for reactions and phase transitions: applications to protein stabilization, hydrates and catalysis

    E-Print Network [OSTI]

    Anderson, Brian J.

    In this work we have made significant contributions in three different areas of interest: therapeutic protein stabilization, thermodynamics of natural gas clathrate-hydrates, and zeolite catalysis. In all three fields, ...

  14. Dynamical heterogeneities in an attraction driven colloidal glass

    E-Print Network [OSTI]

    Antonio M. Puertas; Matthias Fuchs; Michael E. Cates

    2006-01-16T23:59:59.000Z

    The dynamical heterogeneities (DH) in non-ergodic states of an attractive colloidal glass are studied, as a function of the waiting time. Whereas the fluid states close to vitrify showed strong DH, the distribution of squared displacements of the glassy states studied here only present a tail of particles with increased mobility for the lower attraction strength at short waiting times. These particles are in the surface of the percolating cluster that comprises all of the particles, reminiscent of the fastest particles in the fluid. The quench deeper into the attractive glass is dynamically more homogeneous, in agreement with repulsive glasses (i.e. Lennard-Jones glass).

  15. Microgrids and Heterogeneous Security, Quality, Reliability, andAvailability

    SciTech Connect (OSTI)

    Marnay, Chris

    2007-01-31T23:59:59.000Z

    This paper describes two stylized alternative visions inpopular currencyof how the power system might evolve to meet futurerequirements for the high quality electricity service that modern digitaleconomies demand, a supergrids paradigm and a dispersed paradigm. Some ofthe economics of the dispersed vision are explored. Economic perspectivesare presented on both the choice of homogeneous universal power qualityupstream in the electricity supply, and also on the extremelyheterogeneous require-ments of end-use loads. Finally, the potential roleof microgrids in delivering heterogeneous power quality is demonstratedby reference to two ongoing microgrid tests in the U.S. andJapan.

  16. A Note on KKT Points of Homogeneous Programs 1'

    E-Print Network [OSTI]

    2005-07-11T23:59:59.000Z

    A Note on KKT Points of Homogeneous Programs 1'. Y. B. Zhao 2 and D. Li 3. Abstract. Homogeneous programming is an important class of optimization ...

  17. Analytical modeling of the interaction of enzyme catalysis and diffusion processes at the intracellular level

    E-Print Network [OSTI]

    Faith, Duane Willbern

    1977-01-01T23:59:59.000Z

    ANALYTICAL MODELING OF THE INTERACTION OF ENZYME CATALYSIS AND DIFFUSION PROCESSES AT THE INTRACELLULAR LEVEL A Thesis by Duane Nillbern Faith Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1977 Major Subject: Bioengineering ANALYTICAL MODELING OF THE INTERACTION OF ENZYME CATALYSIS AND DIFFUSION PROCESSES AT THE INTRACELLULAR LEVEL A Thesis by Duane Willbern Faith Approved as to style and content by...

  18. Studies of the relationship of protein structure to regulation and catalysis in tyrosine hydroxylase

    E-Print Network [OSTI]

    Sura, Giri Raju

    2007-09-17T23:59:59.000Z

    STUDIES OF THE RELATIONSHIP OF PROTEIN STRUCTURE TO REGULATION AND CATALYSIS IN TYROSINE HYDROXYLASE A Dissertation by GIRI RAJU SURA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2006 Major Subject: Biochemistry STUDIES OF THE RELATIONSHIP OF PROTEIN STRUCTURE TO REGULATION AND CATALYSIS IN TYROSINE HYDROXYLASE A Dissertation by GIRI RAJU...

  19. Final Report on Kokes Awards for the 20th North American Catalysis Society Meeting

    SciTech Connect (OSTI)

    Wong, Michael S

    2008-12-31T23:59:59.000Z

    This Final Report describes how the Kokes Awards program was carried out for the 2007 meeting with regard to selection of students and disbursement of funds received from DOE and other sources. The objective of the Richard J. Kokes Travel Award program of the American Catalysis Society is to encourage graduate students to attend and participate meaningfully in the biennial North American Catalysis Society Meeting.

  20. Conceptual design of a new homogeneous reactor for medical radioisotope Mo-99/Tc-99m production

    SciTech Connect (OSTI)

    Liem, Peng Hong [Nippon Advanced Information Service (NAIS Co., Inc.) Scientific Computational Division, 416 Muramatsu, Tokaimura, Ibaraki (Japan); Tran, Hoai Nam [Chalmers University of Technology, Dept. of Applied Physics, Div. of Nuclear Engineering, SE-412 96 Gothenburg (Sweden); Sembiring, Tagor Malem [National Nuclear Energy Agency (BATAN), Center for Reactor Technology and Nuclear Safety, Kawasan Puspiptek, Serpong, Tangerang Selatan, Banten (Indonesia); Arbie, Bakri [PT MOTAB Technology, Kedoya Elok Plaza Blok DA 12, Jl. Panjang, Kebun Jeruk, Jakarta Barat (Indonesia)

    2014-09-30T23:59:59.000Z

    To partly solve the global and regional shortages of Mo-99 supply, a conceptual design of a nitrate-fuel-solution based homogeneous reactor dedicated for Mo-99/Tc-99m medical radioisotope production is proposed. The modified LEU Cintichem process for Mo-99 extraction which has been licensed and demonstrated commercially for decades by BATAN is taken into account as a key design consideration. The design characteristics and main parameters are identified and the advantageous aspects are shown by comparing with the BATAN's existing Mo-99 supply chain which uses a heterogeneous reactor (RSG GAS multipurpose reactor)

  1. Chimera states in heterogeneous networks

    E-Print Network [OSTI]

    Carlo R. Laing

    2008-12-17T23:59:59.000Z

    Chimera states in networks of coupled oscillators occur when some fraction of the oscillators synchronise with one another, while the remaining oscillators are incoherent. Several groups have studied chimerae in networks of identical oscillators, but here we study these states in a heterogeneous model for which the natural frequencies of the oscillators are chosen from a distribution. We obtain exact results by reduction to a finite set of differential equations. We find that heterogeneity can destroy chimerae, destroy all states except chimerae, or destabilise chimerae in Hopf bifurcations, depending on the form of the heterogeneity.

  2. Sensitivity Analysis of Combustion Timing of Homogeneous

    E-Print Network [OSTI]

    Stefanopoulou, Anna

    to predict the start of combustion in a homogeneous charge compression ignition (HCCI) engine. Qualitative and quantitative information on the individual effects of fuel and exhaust gas recirculation on the HCCI combustion-injection gasoline HCCI engine, we find that temperature is the dominant factor in determining the start

  3. Portable performance on heterogeneous architectures

    E-Print Network [OSTI]

    Phothilimthana, Phitchaya Mangpo

    Trends in both consumer and high performance computing are bringing not only more cores, but also increased heterogeneity among the computational resources within a single machine. In many machines, one of the greatest ...

  4. A hierarchical framework for the multiscale modeling of microstructure evolution in heterogeneous materials.

    SciTech Connect (OSTI)

    Luscher, Darby J.

    2010-04-01T23:59:59.000Z

    All materials are heterogeneous at various scales of observation. The influence of material heterogeneity on nonuniform response and microstructure evolution can have profound impact on continuum thermomechanical response at macroscopic “engineering” scales. In many cases, it is necessary to treat this behavior as a multiscale process thus integrating the physical understanding of material behavior at various physical (length and time) scales in order to more accurately predict the thermomechanical response of materials as their microstructure evolves. The intent of the dissertation is to provide a formal framework for multiscale hierarchical homogenization to be used in developing constitutive models.

  5. Applied Catalysis A: General 192 (2000) 227234 Hydrogen production via the direct cracking of methane over Ni/SiO2

    E-Print Network [OSTI]

    zur Loye, Hans-Conrad

    2000-01-01T23:59:59.000Z

    Applied Catalysis A: General 192 (2000) 227­234 Hydrogen production via the direct cracking al. / Applied Catalysis A: General 192 (2000) 227­234 to be the diffusion of carbon through the metal

  6. Role of adsorption in catalysis: applications of NMR relaxometry

    E-Print Network [OSTI]

    Arias Vecino, Pablo

    2015-06-09T23:59:59.000Z

    for the desired products. A successful example is the three-way catalyst, which effectively reduces pollution from car engines (Niemantsverdriet, 2000). Other important processes involving heterogeneous catalysts include the Haber-Bosch process for ammonia... against the %d-character, defined as the contribution of the d-electrons to the spd hybrid orbitals in Resonance Band Valence Theory. The figure shows a volcano-shaped plot, indicative of the differences between weak adsorption vs. hindered desorption...

  7. On the energy of homogeneous cosmologies

    E-Print Network [OSTI]

    James M. Nester; Lau Loi So; T. Vargas

    2008-03-23T23:59:59.000Z

    An energy for the homogeneous cosmological models is presented. More specifically, using an appropriate natural prescription, we find the energy within any region with any gravitational source for a large class of gravity theories--namely those with a tetrad description--for all 9 Bianchi types. Our energy is given by the value of the Hamiltonian with homogeneous boundary conditions; this value vanishes for all regions in all Bianchi class A models, and it does not vanish for any class B model. This is so not only for Einstein's general relativity but, moreover, for the whole 3-parameter class of tetrad-teleparallel theories. For the physically favored one parameter subclass, which includes the teleparallel equivalent of Einstein's theory as an important special case, the energy for all class B models is, contrary to expectation, negative.

  8. Homogeneous Einstein metrics on SU(n)

    E-Print Network [OSTI]

    Abid H. Mujtaba

    2011-10-10T23:59:59.000Z

    It is known that every compact simple Lie group admits a bi-invariant homogeneous Einstein metric. In this paper we use two ansatz to probe the existence of additional inequivalent Einstein metrics on the Lie group SU (n) for arbitrary n. We provide an explicit construction of (2k+1) inequivalent Einstein metrics on SU (2k) and 2k inequivalent Einstein metrics on SU (2k + 1).

  9. Simulations on the effects of confinement and Ni-catalysis on the formation of tubular fullerene structures from peapod precursors

    E-Print Network [OSTI]

    Goddard III, William A.

    Simulations on the effects of confinement and Ni-catalysis on the formation of tubular fullerene April 2007 We applied the recently developed reactive force field ReaxFF to study the dynamics buckyballs. This barrier is lowered by 40% with the aid of Ni-catalysis. This research can help the community

  10. Asymmetric Catalysis on Sequentially-Linked Columns Ahmed M. Hafez, Andrew E. Taggi, Travis Dudding, and Thomas Lectka*

    E-Print Network [OSTI]

    Lectka, Thomas

    Asymmetric Catalysis on Sequentially-Linked Columns Ahmed M. Hafez, Andrew E. Taggi, Travis Dudding of a series of "reaction columns". This process was applied to the catalytic asymmetric synthesis of -lactams that they conduct chemical reactions. In regard to chiral synthesis and drug discovery, asymmetric catalysis1

  11. Molecular-level Design of Heterogeneous Chiral Catalysts

    SciTech Connect (OSTI)

    Gellman, Andrew John [Carnegie Mellon University; Sholl, David S. [Georgia Institute of Technology; Tysoe, Wilfred T. [University of Wisconsin - Milwaukee; Zaera, Francisco [University of California at Riverside

    2013-04-28T23:59:59.000Z

    Understanding and controlling selectivity is one of the key challenges in heterogeneous catalysis. Among problems in catalytic selectivity enantioselectivity is perhaps the most the most challenging. The primary goal of the project on “Molecular-level Design of Heterogeneous Chiral Catalysts” is to understand the origins of enantioselectivity on chiral heterogeneous surfaces and catalysts. The efforts of the project team include preparation of chiral surfaces, characterization of chiral surfaces, experimental detection of enantioselectivity on such surfaces and computational modeling of the interactions of chiral probe molecules with chiral surfaces. Over the course of the project period the team of PI’s has made some of the most detailed and insightful studies of enantioselective chemistry on chiral surfaces. This includes the measurement of fundamental interactions and reaction mechanisms of chiral molecules on chiral surfaces and leads all the way to rationale design and synthesis of chiral surfaces and materials for enantioselective surface chemistry. The PI’s have designed and prepared new materials for enantioselective adsorption and catalysis. Naturally Chiral Surfaces • Completion of a systematic study of the enantiospecific desorption kinetics of R-3-methylcyclohexanone (R-3-MCHO) on 9 achiral and 7 enantiomeric pairs of chiral Cu surfaces with orientations that span the stereographic triangle. • Discovery of super-enantioselective tartaric acid (TA) and aspartic acid (Asp) decomposition as a result of a surface explosion mechanism on Cu(643)R&S. Systematic study of super-enantiospecific TA and Asp decomposition on five enantiomeric pairs of chiral Cu surfaces. • Initial observation of the enantiospecific desorption of R- and S-propylene oxide (PO) from Cu(100) imprinted with {3,1,17} facets by L-lysine adsorption. Templated Chiral Surfaces • Initial observation of the enantiospecific desorption of R- and S-PO from Pt(111) and Pd(111) modified by a variety of chiral templates. • Demonstrated enantioselective separation of racemic PO on chemically synthesized chiral gold nanoparticles. • Discovery of zwitterionic adsorption states of amino acids on Pd(111). • First structure determinations of adsorbed amino acids and identification of tetrameric chiral template structures. • Exploration of the enantiospecific interaction of PO and R-3-MCHO adsorption on chirally modified Cu(100), Cu(110) and Cu(111). One-to-One Interactions • Determination of cinchona orientation on Pt surfaces in situ at the solid-liquid interface using FT-IRAS. • Systematic study of the influence of solution properties on the adsorption of modified cinchonas alkaloids onto Pt surfaces. • Correlation of cinchona adsorption with catalytic activity, as affected by concentration, the nature of the solvent, and dissolved gases in the liquid phase. • Measurement of enantioselective chemisorption on 1-(1-naphthyl) ethylamine (NEA) modified Pt(111) and Pd(111) surfaces. • Imaging of chiral docking complexes between NEA and methyl pyruvate on Pd(111). Chiral Catalyst Synthesis • Anchoring of cinchona alkaloid to surfaces • Synthesis of chiral Au nanoparticles and demonstration of their enantiospecific interactions with R- and S-PO. • Elucidation of the driving forces for chiral imprinting of Cu(100) by L- and D-lysine to form Cu(3,1,17)R&S facets.

  12. 2010 CATALYSIS GORDON RESEARCH CONFERENCE, JUNE 27 - JULY 2, 2010, NEW LONDON, NEW HAMPSHIRE

    SciTech Connect (OSTI)

    Abhaya Datye

    2010-07-02T23:59:59.000Z

    Catalysis is a key technology for improving the quality of life while simultaneously reducing the adverse impact of human activities on the environment. The discovery of new catalytic processes and the improvement of existing ones are also critically important for securing the nation's energy supply. The GRC on Catalysis is considered one the most prestigious conference for catalysis research, bringing together leading researchers from both academia, industry and national labs to discuss the latest, most exciting research in catalysis and the future directions for the field. The 2010 GRC on Catalysis will follow time-honored traditions and feature invited talks from the world's leading experts in the fundamentals and applications of catalytic science and technology. We plan to have increased participation from industry. The extended discussions in the company of outstanding thinkers will stimulate and foster new science. The conference will include talks in the following areas: Alternative feedstocks for chemicals and fuels, Imaging and spectroscopy, Design of novel catalysts, Catalyst preparation fundamentals, Molecular insights through theory, Surface Science, Catalyst stability and dynamics. In 2010, the Catalysis conference will move to a larger conference room with a new poster session area that will allow 40 posters per session. The dorm rooms provide single and double accommodations, free WiFi and the registration fee includes all meals and the famous lobster dinner on Thursday night. Afternoons are open to enjoy the New England ambiance with opportunities for hiking, sailing, golf and tennis to create an outstanding conference that will help you network with colleagues, and make long lasting connections.

  13. Growth mechanism of graphene on platinum: Surface catalysis and carbon segregation

    SciTech Connect (OSTI)

    Sun, Jie, E-mail: jie.sun@chalmers.se; Lindvall, Niclas; Yurgens, August [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Nam, Youngwoo [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Cole, Matthew T. [Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, CB3 0FA Cambridge (United Kingdom); Teo, Kenneth B. K. [AIXTRON Nanoinstruments Ltd., Swavesey, CB24 4FQ Cambridge (United Kingdom); Woo Park, Yung [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2014-04-14T23:59:59.000Z

    A model of the graphene growth mechanism of chemical vapor deposition on platinum is proposed and verified by experiments. Surface catalysis and carbon segregation occur, respectively, at high and low temperatures in the process, representing the so-called balance and segregation regimes. Catalysis leads to self-limiting formation of large area monolayer graphene, whereas segregation results in multilayers, which evidently “grow from below.” By controlling kinetic factors, dominantly monolayer graphene whose high quality has been confirmed by quantum Hall measurement can be deposited on platinum with hydrogen-rich environment, quench cooling, tiny but continuous methane flow and about 1000?°C growth temperature.

  14. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    SciTech Connect (OSTI)

    Keith James Stanger

    2003-05-31T23:59:59.000Z

    The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-{alpha}-acetamidocinnamate (MAC), has the illustrated structure as established by {sup 31}P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]{sub 4}, [Rh(COD){sub 2}]{sup +}BF{sub 4}{sup -}, [Rh(COD)Cl]{sub 2}, and RhCl{sub 3} {center_dot} 3H{sub 2}O, adsorbed on SiO{sub 2} are optimally activated for toluene hydrogenation by pretreatment with H{sub 2} at 200 C. The same complexes on Pd-SiO{sub 2} are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH{sub 2}){sub 3}s-]Re(O)(Me)(PPh{sub 3}) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.

  15. Evidence for heterogeneity in facioscapulohumeral muscular dystrophy (FSHD)

    SciTech Connect (OSTI)

    Gilbert, J.R.; Stajich, J.M.; Wall, S.; Carter, S.C.; Qiu, H.; Vance, J.M.; Stewart, C.S.; Speer, M.C.; Pufky, J.; Yamaoka, L.H.; Rozear, M.; Roses, A.D.; Pericak-Vance, M.A. (Duke Univ. Medical Center, Durham, NC (United States)); Samson, F.; Fardeau, M. (INSERM, Paris (France))

    1993-08-01T23:59:59.000Z

    Facioscapulohumeral muscular dystrophy (FSHD) is a slowly progressive primary disease of muscle which is usually inherited as an autosomal dominant disorder. FSHD has been localized to the long arm of chromosome 4, specifically to the 4q3.5-qter region. Initially published linkage studies showed no evidence for heterogeneity in FSHD. In the present study the authors have examined individuals in seven FSHD families. Two-point lod scores show significant evidence for linkage for D4S163 (lod score 3.04 at recombination fraction .21) and D4S139 (lod score 3.84 at recombination fraction .20). D4S171 also gave a positive score (lod score 2.56 at recombination fraction .24). Significant evidence for heterogeneity was found for each of the three markers. Multipoint linkage analysis in this region resulted in a peak multipoint lod score of 6.47. The multipoint analysis supported the two-point studies with odds of 20:1 showing linkage and heterogeneity over linkage and homogeneity. Five of the seven families gave a posterior probability of >95% of being of the linked type, while two families appeared unlinked to this region of 4q (P<.01%). Individuals in the two unlinked families met the clinical criteria for the diagnosis of FSHD, including facial weakness, clavicular flattening, scapula winging, proximal muscle weakness, and myopathic changes on muscle biopsies without inflammatory or mitochondrial pathology. This study demonstrates genetic heterogeneity in FSHD and has important implications for both genetic counseling and the elucidation of the etiology of FSHD. 19 refs., 3 figs., 2 tabs.

  16. Gauge Theories in Noncommutative Homogeneous Kähler Manifolds

    E-Print Network [OSTI]

    Yoshiaki Maeda; Akifumi Sako; Toshiya Suzuki; Hiroshi Umetsu

    2014-09-07T23:59:59.000Z

    We construct a gauge theory on a noncommutative homogeneous K\\"ahler manifold, where we employ the deformation quantization with separation of variables for K\\"ahler manifolds formulated by Karabegov. A key point in this construction is to obtaining vector fields which act as inner derivations for the deformation quantization. We show that these vector fields are the only Killing vector fields. We give an explicit construction of this gauge theory on noncommutative ${\\mathbb C}P^N$ and noncommutative ${\\mathbb C}H^N$.

  17. High Throughput Sample Preparation and Analysis for DNA Sequencing, PCR and Combinatorial Screening of Catalysis Based on Capillary Array Technique

    SciTech Connect (OSTI)

    Yonghua Zhang

    2002-05-27T23:59:59.000Z

    Sample preparation has been one of the major bottlenecks for many high throughput analyses. The purpose of this research was to develop new sample preparation and integration approach for DNA sequencing, PCR based DNA analysis and combinatorial screening of homogeneous catalysis based on multiplexed capillary electrophoresis with laser induced fluorescence or imaging UV absorption detection. The author first introduced a method to integrate the front-end tasks to DNA capillary-array sequencers. protocols for directly sequencing the plasmids from a single bacterial colony in fused-silica capillaries were developed. After the colony was picked, lysis was accomplished in situ in the plastic sample tube using either a thermocycler or heating block. Upon heating, the plasmids were released while chromsomal DNA and membrane proteins were denatured and precipitated to the bottom of the tube. After adding enzyme and Sanger reagents, the resulting solution was aspirated into the reaction capillaries by a syringe pump, and cycle sequencing was initiated. No deleterious effect upon the reaction efficiency, the on-line purification system, or the capillary electrophoresis separation was observed, even though the crude lysate was used as the template. Multiplexed on-line DNA sequencing data from 8 parallel channels allowed base calling up to 620 bp with an accuracy of 98%. The entire system can be automatically regenerated for repeated operation. For PCR based DNA analysis, they demonstrated that capillary electrophoresis with UV detection can be used for DNA analysis starting from clinical sample without purification. After PCR reaction using cheek cell, blood or HIV-1 gag DNA, the reaction mixtures was injected into the capillary either on-line or off-line by base stacking. The protocol was also applied to capillary array electrophoresis. The use of cheaper detection, and the elimination of purification of DNA sample before or after PCR reaction, will make this approach an attractive alternative to current methods for genetic analysis and disease diagnosis.

  18. New multilateral well architecture in heterogeneous reservoirs

    E-Print Network [OSTI]

    Jia, Hongqiao

    2004-09-30T23:59:59.000Z

    . The performance of new multilateral well in heterogeneous reservoirs is studied, and that is compared with vertical well architecture also. In order to study the productivity of new multilateral wells, we use a numerical simulation method to set up heterogeneous...

  19. Mesoscale harmonic analysis of homogenous dislocation nucleation

    E-Print Network [OSTI]

    Asad Hasan; Craig E. Maloney

    2012-05-08T23:59:59.000Z

    We perform atomistic computer simulations to study the mechanism of homogeneous dislocation nucleation in two dimensional (2D) hexagonal crystalline films during indentation with a circular nanoindenter. The nucleation process is governed by the vanishing of the energy associated with a single normal mode. This critical mode is largely confined to a single plane of adjacent atoms. For fixed film thickness, L, the spatial extent, \\xi, of the critical mode grows with indenter radius, R. For fixed R/L, the spatial extent \\xi, grows roughly as \\xi ~ L^0.4. We, furthermore, perform a mesoscale analysis to determine the lowest energy normal mode for mesoscale regions of varying radius, r_{meso}, centered on the critical mode's core. The energy, \\lambda_{meso}, of the lowest normal mode in the meso-region decays very rapidly with r_{meso} and \\lambda_{meso} ~= 0 for r_{meso} >~ \\xi. The lowest normal mode shows a spatial extent, \\xi_{meso}, which has a sublinear power-law increase with r_{meso} for r_{meso} mesoscale analysis gives good estimates for the energy and spatial extent of the critical mode \\emph{only} for r_{meso} >~ 1.5 \\xi. In this sense homogeneous dislocation nucleation should be understood as a quasi-local phenomenon.

  20. 337th Catalysis Research Center (CRC) Colloquium Fluorine Industry in China

    E-Print Network [OSTI]

    Ishii, Hitoshi

    337th Catalysis Research Center (CRC) Colloquium Fluorine Industry in China Lu Long (Shanghai industries in China, the second largest economy in the world. In this presentation, fluorine industry in China and the potential business opportunity will be discussed briefly, including inorganic fluorides

  1. Enzyme-Like Catalysis of the Nazarov Cyclization by Supramolecular Encapsulation

    SciTech Connect (OSTI)

    Hastings, Courtney; Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2010-03-29T23:59:59.000Z

    A primary goal in the design and synthesis of molecular hosts has been the selective recognition and binding of a variety of guests using non-covalent interactions. Supramolecular catalysis, which is the application of such hosts towards catalysis, has much in common with many enzymatic reactions, chiefly the use of both spatially appropriate binding pockets and precisely oriented functional groups to recognize and activate specific substrate molecules. Although there are now many examples which demonstrate how selective encapsulation in a host cavity can enhance the reactivity of a bound guest, all have failed to reach the degree of increased reactivity typical of enzymes. We now report the catalysis of the Nazarov cyclization by a self-assembled coordination cage, a carbon-carbon bond-forming reaction which proceeds under mild, aqueous conditions. The acceleration in this system is over a million-fold, and represents the first example of supramolecular catalysis that achieves the level of rate enhancement comparable to that observed in several enzymes. We explain the unprecedented degree of rate increase as due to the combination of (a) preorganization of the encapsulated substrate molecule, (b) stabilization of the transition state of the cyclization by constrictive binding, and (c) increase in the basicity of the complexed alcohol functionality.

  2. Challenges for the application of quantum chemical calculations to problems in catalysis

    E-Print Network [OSTI]

    Bell, Alexis T.

    2004) A long-standing goal of researchers in the field of catalysis is to develop first-principles of a catalysed reaction occurring in a reactor given knowledge only of reactor configuration, catalyst accurate determinations of reactor performance given a set of rate parameters describing catalyst

  3. Enantioselective Organocatalytic Indole Alkylations. Design of a New and Highly Effective Chiral Amine for Iminium Catalysis

    E-Print Network [OSTI]

    MacMillan, David W. C.

    structural motifs of established value in medicinal chemistry or complex target synthesis. In this regard the capacity of iminium catalysis to mediate the enantioselective coupling of pyrroles and R, -unsaturated alde nucleophiles. Despite struc- tural similarities, it has long been established7 that the pyrrole -system

  4. Applied Catalysis A: General 254 (2003) 97106 Photoionization detection (PID) as a high throughput

    E-Print Network [OSTI]

    Senkan, Selim M.

    Applied Catalysis A: General 254 (2003) 97­106 Photoionization detection (PID) as a high throughput 2002 Abstract A versatile photoionization detection (PID) system has been developed to rapidly screen libraries of catalytic materials. The PID approach involves the use of an appropriately selected dc

  5. High surface area crystalline titanium dioxide: potential and limits in electrochemical energy storage and catalysis

    E-Print Network [OSTI]

    Pfeifer, Holger

    High surface area crystalline titanium dioxide: potential and limits in electrochemical energy-Planck-Institut für Polymerforschung, Ackermannweg 10, D-55128 Mainz, Germany Abstract Titanium dioxide is one, as support in catalysis etc. Common synthesis methods of titanium dioxide typically require a high

  6. Argonne National Laboratory Chemical Engineering Division Water-gas shift catalysis

    E-Print Network [OSTI]

    Argonne National Laboratory Chemical Engineering Division Water-gas shift catalysis Sara Yu Choung Engineering Division Argonne National Laboratory Hydrogen, Fuel Cells, and Infrastructure Technologies 2003 Merit Review Berkeley, CA May 19-22, 2003 #12;Argonne National Laboratory Chemical Engineering Division

  7. Catalysis Today 77 (2002) 6578 CO-free fuel processing for fuel cell applications

    E-Print Network [OSTI]

    Goodman, Wayne

    2002-01-01T23:59:59.000Z

    Catalysis Today 77 (2002) 65­78 CO-free fuel processing for fuel cell applications T.V. Choudhary In view of the stringent CO intolerance of the state-of-the-art proton exchange membrane (PEM) fuel cells of hydrocarbons has been proposed for production of CO-free hydrogen for fuel cell applications. The decomposition

  8. Calculational and experimental investigations of void effect -- A simple theoretical model for space-dependent leakage treatment of heterogeneous assemblies

    SciTech Connect (OSTI)

    Benoist, P.; Petrovic, I. (Commissariat a' l'Energie Atomique, Gif-sur-Yvette (France)); Mondot, J. (Commissariat a l'Energie Atomique, Saint Paul lez Durance (France))

    1994-12-01T23:59:59.000Z

    This method, which takes into account the influence of assembly heterogeneity on neutron leakage, is based on the heterogeneous B[sub 1] formalism, which assumes the existence of a fundamental mode in an infinite and regular lattice of heterogeneous assemblies. A simplified formalism, TIBERE, is presented that allows one to define directional space-dependent leakage coefficients. This method, introduced for two-dimensional x-y geometry in the APOLLO-2 multigroup transport code, uses classical and directional first-flight collision probabilities. One can now define leakage cross sections as additional absorption cross sections that have space and energy dependence, as well as all other cross sections. Hence, one obtains perfectly consistent reaction and leakage rates used in an equivalence procedure, determining cell-homogenized parameters for a whole core calculation. The study of this refined heterogeneous leakage treatment was undertaken because of the insufficiency of the homogeneous leakage model, especially in cases when an assembly contain voided zones or almost voided zones, i.e., zones with a long mean free path, so that the streaming effect may become important. The fission rate comparison between the EPICURE reactor experimental results and the results of the corresponding whole reactor calculations were accomplished, with leakages calculated by the homogeneous and the TIBERE procedures of the APOLLO-2 code.

  9. Enhancing quantum entanglement and quantum teleportation for two-mode squeezed vacuum state by local quantum-optical catalysis

    E-Print Network [OSTI]

    Xue-xiang Xu

    2015-03-17T23:59:59.000Z

    I investigate how the entanglement properties of a two-mode squeezed vacuum state (TMSVS) can be enhanced by operating quantum-optical catalysis, proposed by Lovvky and Mlynek [Phys. Rev. Lett. 88, 250404 (2002)], on each mode. I show that the degree of entanglement, the Eistein-Podolsky-Rosen-type correlation, and the performance of quantum teleportation can be all enhanced for the output state when the appropriate quantum-optical catalysis is applied to a TMSVS. It is found that all the enhancements are happened in the small-squeezing and small-catalysis parameter regime.

  10. Homogeneous catalyst formulations for methanol production

    DOE Patents [OSTI]

    Mahajan, Devinder (Port Jefferson, NY); Sapienza, Richard S. (Shoreham, NY); Slegeir, William A. (Hampton Bays, NY); O'Hare, Thomas E. (Huntington Station, NY)

    1991-02-12T23:59:59.000Z

    There is disclosed synthesis of CH.sub.3 OH from carbon monoxide and hydrogen using an extremely active homogeneous catalyst for methanol synthesis directly from synthesis gas. The catalyst operates preferably between 100.degree.-150.degree. C. and preferably at 100-150 psia synthesis gas to produce methanol. Use can be made of syngas mixtures which contain considerable quantities of other gases, such as nitrogen, methane or excess hydrogen. The catalyst is composed of two components: (a) a transition metal carbonyl complex and (b) an alkoxide component. In the simplest formulation, component (a) is a complex of nickel tetracarbonyl and component (b) is methoxide (CH.sub.3 O.sup.-), both being dissolved in a methanol solvent system. The presence of a co-solvent such as p-dioxane, THF, polyalcohols, ethers, hydrocarbons, and crown ethers accelerates the methanol synthesis reaction.

  11. Homogeneous catalyst formulations for methanol production

    DOE Patents [OSTI]

    Mahajan, Devinder (Port Jefferson, NY); Sapienza, Richard S. (Shoreham, NY); Slegeir, William A. (Hampton Bays, NY); O'Hare, Thomas E. (Huntington Station, NY)

    1990-01-01T23:59:59.000Z

    There is disclosed synthesis of CH.sub.3 OH from carbon monoxide and hydrogen using an extremely active homogeneous catalyst for methanol synthesis directly from synthesis gas. The catalyst operates preferably between 100.degree.-150.degree. C. and preferably at 100-150 psia synthesis gas to produce methanol. Use can be made of syngas mixtures which contain considerable quantities of other gases, such as nitrogen, methane or excess hydrogen. The catalyst is composed of two components: (a) a transition metal carbonyl complex and (b) an alkoxide component. In the simplest formulation, component (a) is a complex of nickel tetracarbonyl and component (b) is methoxide (CH.sub.3 O.sup.13 ), both being dissolved in a methanol solvent system. The presence of a co-solvent such as p-dioxane, THF, polyalcohols, ethers, hydrocarbons, and crown ethers accelerates the methanol synthesis reaction.

  12. Solvation and Acid Strength Effects on Catalysis by Faujasite Zeolites

    SciTech Connect (OSTI)

    Gounder, Rajamani P.; Jones, Andrew J.; Carr, Robert T.; Iglesia, Enrique

    2012-02-01T23:59:59.000Z

    Kinetic, spectroscopic, and chemical titration data indicate that differences in monomolecular isobutane cracking and dehydrogenation and methanol dehydration turnover rates (per H+) among FAU zeolites treated thermally with steam (H-USY) and then chemically with ammonium hexafluorosilicate (CDHUSY) predominantly reflect differences in the size and solvating properties of their supercage voids rather than differences in acid strength. The number of protons on a given sample was measured consistently by titrations with Na+, with CH3 groups via reactions of dimethyl ether, and with 2,6-di-tert-butylpyridine during methanol dehydration catalysis; these titration values were also supported by commensurate changes in acidic OH infrared band areas upon exposure to titrant molecules. The number of protons, taken as the average of the three titration methods, was significantly smaller than the number of framework Al atoms (Alf) obtained from X-ray diffraction and 27Al magic angle spinning nuclear magnetic resonance spectroscopy on H-USY (0.35 H+/Alf) and CD-HUSY (0.69 H+/Alf). These data demonstrate that the ubiquitous use of Alf sites as structural proxies for active H+ sites in zeolites can be imprecise, apparently because distorted Al structures that are not associated with acidic protons are sometimes detected as Alf sites. Monomolecular isobutane cracking and dehydrogenation rate constants, normalized non-rigorously by the number of Alf species, decreased with increasing Na+ content on both H-USY and CD-HUSY samples and became undetectable at sub-stoichiometric exchange levels (0.32 and 0.72 Na+/Alf ratios, respectively), an unexpected finding attributed incorrectly in previous studies to the presence of minority ‘‘super-acidic’’ sites. These rate constants, when normalized rigorously by the number of residual H+ sites were independent of Na+ content on both H-USY and CD-HUSY samples, reflecting the stoichiometric replacement of protons that are uniform in reactivity by Na+ cations. Monomolecular isobutane cracking and dehydrogenation rate constants (per H+; 763 K), however, were higher on H-USY than CD-HUSY (by a factor of 1.4). Equilibrium constants for the formation of protonated methanol dimers via adsorption of gaseous methanol onto adsorbed methanol monomers, determined from kinetic studies of methanol dehydration to dimethyl ether (433 K), were also higher on H-USY than CD-HUSY (by a factor of 2.1). These larger constants predominantly reflect stronger dispersive interactions in H-USY, consistent with its smaller supercage voids that result from the occlusion of void space by extraframework Al (Alex) residues. These findings appear to clarify enduring controversies about the mechanistic interpretation of the effects of Na+ and Alex species on the catalytic reactivity of FAU zeolites. They also illustrate the need to normalize rates by the number of active sites instead of more convenient but less accurate structural proxies for such sites.

  13. The roles of redox active cofactors in catalysis : structural studies of iron sulfur cluster and flavin dependent enzymes

    E-Print Network [OSTI]

    Goldman, Peter John

    2013-01-01T23:59:59.000Z

    Cofactors are highly prevalent in biological systems and have evolved to take on many functions in enzyme catalysis. Two cofactors, flavin adenine dinucleotide (FAD) and [4Fe-4S] clusters, were originally determined to aid ...

  14. Homogenization of a locally-periodic medium with areas of low and high diffusivity

    E-Print Network [OSTI]

    van Noorden, T

    2010-01-01T23:59:59.000Z

    We aim at understanding transport in porous materials including regions with both high and low diffusivities. For such scenarios, the transport becomes structured (here: {\\em micro-macro}). The geometry we have in mind includes regions of low diffusivity arranged in a locally-periodic fashion. We choose a prototypical advection-diffusion system (of minimal size), discuss its formal homogenization (the heterogenous medium being now assumed to be made of zones with circular areas of low diffusivity of $x$-varying sizes), and prove the weak solvability of the limit two-scale reaction-diffusion model. A special feature of our analysis is that most of the basic estimates (positivity, $L^\\infty$-bounds, uniqueness, energy inequality) are obtained in $x$-dependent Bochner spaces.

  15. Ion beam analyses of radionuclide migration in heterogeneous rocks

    SciTech Connect (OSTI)

    Alonso, Ursula; Missana, Tiziana; Garcia-Gutierrez, Miguel [CIEMAT, Avda. Complutense 40, Madrid 28040 (Spain); Patelli, Alessandro [CIVEN, Via delle Industrie 5, Venezia-Marghera 30175 (Italy); Rigato, Valentino; Ceccato, Daniele [LNL-INFN, Viale dell' Universita 2, Legnaro-Padova 35020 (Italy)

    2013-07-18T23:59:59.000Z

    The migration of radionuclides (RN) in the environment is a topic of general interest, for its implications on public health, and it is an issue for the long-term safety studies of deep geological repositories (DGR) for high-level radioactive waste. The role played by colloids on RN migration is also of great concern. Diffusion and sorption are fundamental mechanisms controlling RN migration in rocks and many experimental approaches are applied to determine transport parameters for low sorbing RN in homogeneous rocks. However, it is difficult to obtain relevant data for high sorbing RN or colloids, for which diffusion lengths are extremely short, or within heterogeneous rocks, where transport might be different in different minerals. The ion beam techniques Rutherford Backscattering Spectrometry (RBS) and micro-Particle Induced X-Ray Emission ({mu}PIXE), rarely applied in the field, were selected for their micro-analytical potential to study RN diffusion and surface retention within heterogeneous rocks. Main achievements obtained during last 12 years are highlighted.

  16. The effect of reservoir heterogeneity on gas production from hydrate accumulations in the permafrost

    SciTech Connect (OSTI)

    Reagan, M. T.; Kowalsky, M B.; Moridis, G. J.; Silpngarmlert, S.

    2010-05-01T23:59:59.000Z

    The quantity of hydrocarbon gases trapped in natural hydrate accumulations is enormous, leading to significant interest in the evaluation of their potential as an energy source. Large volumes of gas can be readily produced at high rates for long times from methane hydrate accumulations in the permafrost by means of depressurization-induced dissociation combined with conventional technologies and horizontal or vertical well configurations. Initial studies on the possibility of natural gas production from permafrost hydrates assumed homogeneity in intrinsic reservoir properties and in the initial condition of the hydrate-bearing layers (either due to the coarseness of the model or due to simplifications in the definition of the system). These results showed great promise for gas recovery from Class 1, 2, and 3 systems in the permafrost. This work examines the consequences of inevitable heterogeneity in intrinsic properties, such as in the porosity of the hydrate-bearing formation, or heterogeneity in the initial state of hydrate saturation. Heterogeneous configurations are generated through multiple methods: (1) through defining heterogeneous layers via existing well-log data, (2) through randomized initialization of reservoir properties and initial conditions, and (3) through the use of geostatistical methods to create heterogeneous fields that extrapolate from the limited data available from cores and well-log data. These extrapolations use available information and established geophysical methods to capture a range of deposit properties and hydrate configurations. The results show that some forms of heterogeneity, such as horizontal stratification, can assist in production of hydrate-derived gas. However, more heterogeneous structures can lead to complex physical behavior within the deposit and near the wellbore that may obstruct the flow of fluids to the well, necessitating revised production strategies. The need for fine discretization is crucial in all cases to capture dynamic behavior during production.

  17. Optimization Online - Note: Optimal non-homogeneous composites ...

    E-Print Network [OSTI]

    Tavakoli Rouhollah

    2012-08-29T23:59:59.000Z

    Aug 29, 2012 ... Note: Optimal non-homogeneous composites for dynamic loading revisited. Tavakoli Rouhollah (rtavakoli ***at*** sharif.ir). Abstract: The ...

  18. A Homogeneous Model for P0 and P? Nonlinear Complementarity ...

    E-Print Network [OSTI]

    2005-05-01T23:59:59.000Z

    to P0 CPs starting at a positive point near the central trajectory and does not .... the trajectory induced by the homogeneous model is discussed as an essential.

  19. Towards Realization of Computational Homogenization in Practice1

    E-Print Network [OSTI]

    Fish, Jacob

    demonstrate how to utilize ABAQUS existing facilities to develop analysis attributes required for solving homogenization technologies have been successfully verified and validated; and while industry have abandoned in

  20. Modelling long-distance seed dispersal in heterogeneous landscapes.

    SciTech Connect (OSTI)

    Levey, Douglas, J.; Tewlsbury, Joshua, J.; Bolker, Benjamin, M.

    2008-01-01T23:59:59.000Z

    1. Long-distance seed dispersal is difficult to measure, yet key to understanding plant population dynamics and community composition. 2. We used a spatially explicit model to predict the distribution of seeds dispersed long distances by birds into habitat patches of different shapes. All patches were the same type of habitat and size, but varied in shape. They occurred in eight experimental landscapes, each with five patches of four different shapes, 150 m apart in a matrix of mature forest. The model was parameterized with smallscale movement data collected from field observations of birds. In a previous study we validated the model by testing its predictions against observed patterns of seed dispersal in real landscapes with the same types and spatial configuration of patches as in the model. 3. Here we apply the model more broadly, examining how patch shape influences the probability of seed deposition by birds into patches, how dispersal kernels (distributions of dispersal distances) vary with patch shape and starting location, and how movement of seeds between patches is affected by patch shape. 4. The model predicts that patches with corridors or other narrow extensions receive higher numbers of seeds than patches without corridors or extensions. This pattern is explained by edgefollowing behaviour of birds. Dispersal distances are generally shorter in heterogeneous landscapes (containing patchy habitat) than in homogeneous landscapes, suggesting that patches divert the movement of seed dispersers, ‘holding’ them long enough to increase the probability of seed defecation in the patches. Dispersal kernels for seeds in homogeneous landscapes were smooth, whereas those in heterogenous landscapes were irregular. In both cases, long-distance (> 150 m) dispersal was surprisingly common, usually comprising approximately 50% of all dispersal events. 5. Synthesis . Landscape heterogeneity has a large influence on patterns of long-distance seed dispersal. Our results suggest that long-distance dispersal events can be predicted using spatially explicit modelling to scale-up local movements, placing them in a landscape context. Similar techniques are commonly used by landscape ecologists to model other types of movement; they offer much promise to the study of seed dispersal.

  1. Upscaling of Solute Transport in Heterogeneous Media with Non-uniform Flow and Dispersion Fields

    SciTech Connect (OSTI)

    Xu, Zhijie; Meakin, Paul

    2013-10-01T23:59:59.000Z

    An analytical and computational model for non-reactive solute transport in periodic heterogeneous media with arbitrary non-uniform flow and dispersion fields within the unit cell of length ? is described. The model lumps the effect of non-uniform flow and dispersion into an effective advection velocity Ve and an effective dispersion coefficient De. It is shown that both Ve and De are scale-dependent (dependent on the length scale of the microscopic heterogeneity, ?), dependent on the Péclet number Pe, and on a dimensionless parameter ? that represents the effects of microscopic heterogeneity. The parameter ?, confined to the range of [-0.5, 0.5] for the numerical example presented, depends on the flow direction and non-uniform flow and dispersion fields. Effective advection velocity Ve and dispersion coefficient De can be derived for any given flow and dispersion fields, and . Homogenized solutions describing the macroscopic variations can be obtained from the effective model. Solutions with sub-unit-cell accuracy can be constructed by homogenized solutions and its spatial derivatives. A numerical implementation of the model compared with direct numerical solutions using a fine grid, demonstrated that the new method was in good agreement with direct solutions, but with significant computational savings.

  2. DEFLECTION OF A HETEROGENEOUS WIDE-BEAM UNDER UNIFORM PRESSURE LOAD

    SciTech Connect (OSTI)

    T. V. Holschuh; T. K. Howard; W. R. Marcum

    2014-07-01T23:59:59.000Z

    Oregon State University (OSU) and the Idaho National Laboratory (INL) are currently collaborating on a test program which entails hydro-mechanical testing of a generic plate type fuel element, or generic test plate assembly (GTPA), for the purpose of qualitatively demonstrating mechanical integrity of uranium-molybdenum monolithic plates as compared to that of uranium aluminum dispersion, and aluminum fuel plates onset by hydraulic forces. This test program supports ongoing work conducted for/by the Global Threat Reduction Initiative (GTRI) Fuels Development Program. This study’s focus supports the ongoing collaborative effort by detailing the derivation of an analytic solution for deflection of a heterogeneous plate under a uniform, distributed load in order to predict the deflection of test plates in the GTPA. The resulting analytical solutions for three specific boundary condition sets are then presented against several test cases of a homogeneous plate. In all test cases considered, the results for both homogeneous and heterogeneous plates are numerically identical to one another, demonstrating correct derivation of the heterogeneous solution. Two additional problems are presents herein that provide a representative deflection profile for the plates under consideration within the GTPA. Furthermore, qualitative observations are made about the influence of a more-rigid internal fuel-meat region and its influence on the overall deflection profile of a plate. Present work is being directed to experimentally confirm the analytical solution’s results using select materials.

  3. Homogeneous cosmology with aggressively expanding civilizations

    E-Print Network [OSTI]

    S. Jay Olson

    2014-11-17T23:59:59.000Z

    In the context of a homogeneous universe, we note that the appearance of aggressively expanding advanced life is geometrically similar to the process of nucleation and bubble growth in a first-order cosmological phase transition. We exploit this similarity to describe the dynamics of life saturating the universe on a cosmic scale, adapting the phase transition model to incorporate probability distributions of expansion and resource consumption strategies. Through a series of numerical solutions covering several orders of magnitude in the input assumption parameters, the resulting cosmological model is used to address basic questions related to the intergalactic spreading of life, dealing with issues such as timescales, observability, competition between strategies, and first-mover advantage. Finally, we examine physical effects on the universe itself, such as reheating and the backreaction on the evolution of the scale factor, if such life is able to control and convert a significant fraction of the available pressureless matter into radiation. We conclude that the existence of life, if certain advanced technologies are practical, could have a significant influence on the future large-scale evolution of the universe.

  4. Davydov's Solitons in a Homogeneous Nucleotide Chain

    E-Print Network [OSTI]

    Lakhno, Victor D

    2013-01-01T23:59:59.000Z

    Charge transfer in homogeneous nucleotide chains is modeled on the basis of Holstein Hamiltonian. The path length of Davydov solitons in these chains is being studied. It is shown that in a dispersionless case, when the soliton velocity V is small, the path length grows exponentially as V decreases. In this case the state of a moving soliton is quasisteady. In the presence of dispersion determined by the dependence $\\Omega^2 = \\Omega_0^2 + V_0^2\\kappa^2$ \\, the path length in the region 0 V_0 the soliton motion is accompanied by emission of phonons which leads to a finite path length of a soliton. The latter tends to infinity as $V \\rightarrow V_0 + 0$ and $V \\rightarrow \\infty$. The presence of dissipation leads to a finite soliton path length. An equilibrium velocity of soliton in an external electric field is calculated. It is shown that there is a maximum intensity of an electric field at which a steady motion of a soliton is possible. The soliton mobility is calculated for the stable or ohmic brunch.

  5. Active particles in heterogeneous media display new physics: existence of an optimal noise and absence of bands and long-range order

    E-Print Network [OSTI]

    Chepizhko, Oleksandr

    2015-01-01T23:59:59.000Z

    We present a detailed study of the large-scale collective properties of self-propelled particles (SPPs) moving in two-dimensional heterogeneous spaces. The impact of spatial heterogeneities on the ordered, collectively moving phase is investigated. We show that for strong enough spatial heterogeneity, the well-documented high-density, high-ordered propagating bands that emerge in homogeneous space disappears. Moreover, the ordered phase does not exhibit long-range order, as occurs in homogeneous systems, but rather quasi-long range order: i.e. the SPP system becomes disordered in the thermodynamical limit. For finite size systems, we find that there is an optimal noise value that maximizes order. Interestingly, the system becomes disordered in two limits, for high noise values as well as for vanishing noise. This remarkable finding strongly suggests the existence of two critical points, instead of only one, associated to the collective motion transition. Density fluctuations are consistent with these observat...

  6. Kokes Awards for the 22nd North American Catalysis Society Meeting, June 5-10, 2011

    SciTech Connect (OSTI)

    Fabio H. Ribeiro

    2011-06-05T23:59:59.000Z

    The biennial North American Catalysis Society (NACS) Meetings are the premiere conferences in the area of catalysis, surface science, and reaction engineering. The 22nd meeting will be held the week of June 5-10, 2011 in Detroit, Michigan. The objective of the Meetings is to bring together leading researchers for intensive scientific exchange and interactions. Financial support that offsets some of the associated costs (specifically, registration fee, airline tickets, and hotel accommodations) would encourage graduate students, and for the first time undergraduate students, to attend and participate meaningfully in this conference. The funds sought in this proposal will help support the Richard J. Kokes Travel Award program. Graduate students eligible for these merit-based Awards are those who study at a North American university and who will present at the Meeting. We have currently 209 applications and we expect to be able to fund about half of them. The NACS has traditionally sought to encourage graduate student, and this year for the first time undergraduate studies, participation at the National Meetings and providing financial support is the most effective means to do so. Their attendance would contribute significantly to their scientific training and communication and presentation skills. They would be exposed to the leading researchers from the US and abroad; they would meet their peers from other universities; they would learn about cutting-edge results that could benefit their research projects; and they may become interested in becoming active participants in the catalysis community. These young investigators represent the next generation of scientists and engineers, and their proper training will lead to future scientific breakthroughs and technological innovations that benefit the US economy. Advances in catalysis can come in the form of more energy-efficient and environmentally-friendly chemical processes, improved fuel cell performance, efficient hydrogen production, and a cleaner environment.

  7. Runtime Adaptation for Autonomic Heterogeneous Computing | ornl...

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

    goal is to make the complex functions of heterogeneous computing autonomic, handling load balancing, memory coherence and other performance critical factors in the runtime. This...

  8. Chimera: Hypertext for Heterogeneous Software Environments

    E-Print Network [OSTI]

    Whitehead, James

    Chimera: Hypertext for Heterogeneous Software Environments Kenneth M. Anderson, Richard N. Taylor the approach and presents an architecture which supports it. Experience with the Chimera prototype and its

  9. Feedbacks Between Hydrological Heterogeneity and Bioremediation

    E-Print Network [OSTI]

    Hubbard, Susan

    Feedbacks Between Hydrological Heterogeneity and Bioremediation Induced Biogeochemical, intensively studied over the last 20 years (4), has potential to further impact bioremediation efforts

  10. Joint Center for Artificial Photosynthesis

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

    Catalysis molecular catalysis The Molecular Catalysis Project involves directed discovery of homogeneous catalysts for the key reactions involved in solar-fuel generation:...

  11. MODELING OF NATURALLY FRACTURED RESERVOIRS BY FORMAL HOMOGENIZATION TECHNIQUES*

    E-Print Network [OSTI]

    Douglas Jr., Jim

    MODELING OF NATURALLY FRACTURED RESERVOIRS BY FORMAL HOMOGENIZATION TECHNIQUES* Todd Arbogast,y Jim in naturally fractured reservoirs. A single component in a single phase and two-component mis- cible. porous medium, double porosity, fractured reservoir, homogenization. yDepartment of Mathematics, Purdue

  12. Comparisons of empirical viscous-fingering models and their calibration for heterogeneous problems

    SciTech Connect (OSTI)

    Fayers, F.J.; Blunt, M.J.; Christie, M.A. (BP Research Center (GB))

    1992-05-01T23:59:59.000Z

    This paper reviews the formulation and parameters for three principal empirical viscous-fingering models: the Kovl, Todd and Longstaff, and Fayers methods. All three methods give similar levels of accuracy when compared with linear homogeneous experiments, but they differ in performance in 2D applications. This arises from differences in the formulation of the total mobility terms. The superiority of the Todd and Longstaff and Fayers methods is demonstrated for 2D and gravity-influenced flows by comparison with experiments and high-resolution simulation. The use of high-resolution simulation to calibrate empirical models in a systematic manner is described. Results from detailed simulation demonstrate the sensitivity of empirical model parameters to viscous/gravity ratio, recovery process (secondary, tertiary, or water-alternating-gas (WAG)), and geological heterogeneity. For large amplitude heterogeneities with short correlation lengths, the accuracy of the empirical models is shown to be less satisfactory, but improved by the addition of a diffusive term.

  13. Catalysis Today 151 (2010) 3438 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    history: Available online 24 March 2010 Keywords: Zinc oxide Nanowires Photocatalysis Stearic acid a b rights reserved. 1. Introduction Heterogeneous photocatalysis on semiconductor surfaces has attracted

  14. Chimera: Hypermedia for Heterogeneous Software Development Environments

    E-Print Network [OSTI]

    Whitehead, James

    1 of 31 Chimera: Hypermedia for Heterogeneous Software Development Environments Abstract Emerging of "Chimera: Hypertext for Heterogeneous Software Environments," which appeared in the proceedings of ECHT'94 the approach employed by the Chimera open hypermedia system to address this research area, and also serves

  15. Emerging heterogeneities in Italian customs

    E-Print Network [OSTI]

    Agliari, Elena; Galluzzi, Andrea; Javarone, Marco Alberto; Pizzoferrato, Andrea; Tantari, Daniele

    2015-01-01T23:59:59.000Z

    Since its unification, more than a century ago, Italy has experienced strong social and economical diversities between its southern and northern regions. In the last decades, Italy has undergone a severe economical and political crisis reflecting corruption at various levels of social stratification as well as a poor involvement of its population in the number of elections that occurred. This might be explained by a lack of confidence, or interest in the country as a whole, as if the primary social and political focus of its citizens could still lay at smaller regional scales, possibly evidencing the persistence of different cultural heritages. In order to shed lights on the possible existence of such heterogeneities, we perform a statistical-mechanics-driven analysis focusing on key social quantifiers, namely the evolution of autochthonous marriages (as family still plays as a fundamental brick in the edification of social aggregates) and of mixed marriages, namely those involving a foreign-born and a native...

  16. HETEROGENEOUS REBURNING BY MIXED FUELS

    SciTech Connect (OSTI)

    Wei-Yin Chen; Benson B. Gathitu

    2005-01-14T23:59:59.000Z

    Recent studies of heterogeneous reburning, i.e., reburning involving a coal-derived char, have elucidated its variables, kinetics and mechanisms that are valuable to the development of a highly efficient reburning process. Young lignite chars contain catalysts that not only reduce NO, but they also reduce HCN that is an important intermediate that recycles to NO in the burnout zone. Gaseous CO scavenges the surface oxides that are formed during NO reduction, regenerating the active sites on the char surface. Based on this mechanistic information, cost-effective mixed fuels containing these multiple features has been designed and tested in a simulated reburning apparatus. Remarkably high reduction of NO and HCN has been observed and it is anticipated that mixed fuel will remove 85% of NO in a three-stage reburning process.

  17. Heterogeneous Reburning By Mixed Fuels

    SciTech Connect (OSTI)

    Anderson Hall

    2009-03-31T23:59:59.000Z

    Recent studies of heterogeneous reburning, i.e., reburning involving a coal-derived char, have elucidated its variables, kinetics and mechanisms that are valuable to the development of a highly efficient reburning process. Young lignite chars contain catalysts that not only reduce NO, but they also reduce HCN that is an important intermediate that recycles to NO in the burnout zone. Gaseous CO scavenges the surface oxides that are formed during NO reduction, regenerating the active sites on the char surface. Based on this mechanistic information, cost-effective mixed fuels containing these multiple features has been designed and tested in a simulated reburning apparatus. Remarkably high reduction of NO and HCN has been observed and it is anticipated that mixed fuel will remove 85% of NO in a three-stage reburning process.

  18. Th/U-233 multi-recycle in pressurized water reactors : feasibility study of multiple homogeneous and heterogeneous assembly designs.

    SciTech Connect (OSTI)

    Yun, D.; Taiwo, T. A.; Kim, T. K.; Mohamed, A.; Nuclear Engineering Division

    2010-10-01T23:59:59.000Z

    The use of thorium in current or advanced light water reactors (LWRs) has been of interest in recent years. These interests have been associated with the need to increase nuclear fuel resources and the perceived non-proliferation advantages of the utilization of thorium in the fuel cycle. Various options have been considered for the use of thorium in the LWR fuel cycle. The possibility for thorium utilization in a multi-recycle system has also been considered in past literature, primarily because of the potential for near breeders with Th/U-233 in the thermal energy range. The objective of this study is to evaluate the potential of Th/U-233 fuel multi-recycle in current LWRs, focusing on pressurized water reactors (PWRs). Approaches for sustainable multi-recycle without the need for external fissile material makeup have been investigated. The intent is to obtain a design that allows existing PWRs to be used with minimal modifications.

  19. At tank Low Activity Feed Homogeneity Analysis Verification

    SciTech Connect (OSTI)

    DOUGLAS, J.G.

    2000-09-28T23:59:59.000Z

    This report evaluates the merit of selecting sodium, aluminum, and cesium-137 as analytes to indicate homogeneity of soluble species in low-activity waste (LAW) feed and recommends possible analytes and physical properties that could serve as rapid screening indicators for LAW feed homogeneity. The three analytes are adequate as screening indicators of soluble species homogeneity for tank waste when a mixing pump is used to thoroughly mix the waste in the waste feed staging tank and when all dissolved species are present at concentrations well below their solubility limits. If either of these conditions is violated, then the three indicators may not be sufficiently chemically representative of other waste constituents to reliably indicate homogeneity in the feed supernatant. Additional homogeneity indicators that should be considered are anions such as fluoride, sulfate, and phosphate, total organic carbon/total inorganic carbon, and total alpha to estimate the transuranic species. Physical property measurements such as gamma profiling, conductivity, specific gravity, and total suspended solids are recommended as possible at-tank methods for indicating homogeneity. Indicators of LAW feed homogeneity are needed to reduce the U.S. Department of Energy, Office of River Protection (ORP) Program's contractual risk by assuring that the waste feed is within the contractual composition and can be supplied to the waste treatment plant within the schedule requirements.

  20. Structural and Energetic Heterogeneity in Protein Folding

    E-Print Network [OSTI]

    Steven S. Plotkin; Jose N. Onuchic

    2000-09-27T23:59:59.000Z

    A general theoretical framework is developed using free energy functional methods to understand the effects of heterogeneity in the folding of a well-designed protein. Native energetic heterogeneity arising from non-uniformity in native stability, as well as entropic heterogeneity intrinsic to the topology of the native structure are both investigated as to their impact on the folding free energy landscape and resulting folding mechanism. Given a minimally frustrated protein, both structural and energetic heterogeneity lower the thermodynamic barrier to folding, and designing in sufficient heterogeneity can eliminate the barrier at the folding transition temperature. Sequences with different distributions of stability throughout the protein and correspondingly different folding mechanisms may still be good folders to the same structure. This theoretical framework allows for a systematic study of the coupled effects of energetics and topology in protein folding, and provides interpretations and predictions for future experiments which may investigate these effects.

  1. Hydrogen storage materials and method of making by dry homogenation

    DOE Patents [OSTI]

    Jensen, Craig M. (Kailua, HI); Zidan, Ragaiy A. (Honolulu, HI)

    2002-01-01T23:59:59.000Z

    Dry homogenized metal hydrides, in particular aluminum hydride compounds, as a material for reversible hydrogen storage is provided. The reversible hydrogen storage material comprises a dry homogenized material having transition metal catalytic sites on a metal aluminum hydride compound, or mixtures of metal aluminum hydride compounds. A method of making such reversible hydrogen storage materials by dry doping is also provided and comprises the steps of dry homogenizing metal hydrides by mechanical mixing, such as be crushing or ball milling a powder, of a metal aluminum hydride with a transition metal catalyst. In another aspect of the invention, a method of powering a vehicle apparatus with the reversible hydrogen storage material is provided.

  2. Applied Catalysis A: General 378 (2010) 227233 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    Accepted 22 February 2010 Available online 1 March 2010 Keywords: Nanowires Photocatalysis Aqueous solution heterogeneous photocatalysis, which implies the use of an inert catalyst, non-hazardous oxidants and UV and/or visible light input. Heterogeneous photocatalysis is attracting extensive interest for the degradation

  3. Fuel effects in homogeneous charge compression ignition (HCCI) engines

    E-Print Network [OSTI]

    Angelos, John P. (John Phillip)

    2009-01-01T23:59:59.000Z

    Homogenous-charge, compression-ignition (HCCI) combustion is a new method of burning fuel in internal combustion (IC) engines. In an HCCI engine, the fuel and air are premixed prior to combustion, like in a spark-ignition ...

  4. Tritium Technology Program TTP-1-3089 TPBAR Homogenized Composition

    SciTech Connect (OSTI)

    Love, Edward F.

    2014-10-12T23:59:59.000Z

    Homogenized TPBAR number densities contained herein have been derived for unclassified core physics calculations. The use of this information may not provide accurate, conservative or representative results and must be evaluated for applicability to the specific problem.

  5. Continuum Electrodynamics of a Piecewise-Homogeneous Linear Medium

    E-Print Network [OSTI]

    Crenshaw, Michael E

    2015-01-01T23:59:59.000Z

    The energy--momentum tensor and the tensor continuity equation serve as the conservation laws of energy, linear momentum, and angular momentum for a continuous flow. Previously, we derived equations of motion for macroscopic electromagnetic fields in a homogeneous linear dielectric medium that is draped with a gradient-index antireflection coating (J. Math Phys. 55, 042901 (2014) ). These results are consistent with the electromagnetic tensor continuity equation in the limit that reflections and the accompanying surface forces are negligible thereby satisfying the condition of an unimpeded flow in a thermodynamically closed system. Here, we take the next step and derive equations of motion for the macroscopic fields in the limiting case of a piecewise-homogeneous simple linear dielectric medium. The presence of radiation surface forces on the interface between two different homogeneous linear materials means that the energy--momentum formalism must be modified to treat separate homogeneous media in which the ...

  6. Synthesis of Proteins with Homogenous Chemical and Posttranslational Modifications

    E-Print Network [OSTI]

    Wu, Bo

    2014-06-19T23:59:59.000Z

    Genetic encoding non-canonical amino acids (NCAAs) is a facile approach to synthesize proteins with homogenous modifications. In my graduate study, I demonstrated the application of this approach in the synthesis of a variety of proteins with site...

  7. Dynamics of empty homogeneous isotropic three-dimensional spaces

    E-Print Network [OSTI]

    A. V. Klimenko; V. A. Klimenko

    2012-02-28T23:59:59.000Z

    It is shown that there are seven types of solutions described in the framework of general relativity theory (GRT), the dynamics of empty homogeneous isotropic three-dimensional spaces. Solution of the equations of GRT, which describes the dynamics of a homogeneous isotropic universe, in the limiting case of vanishingly small effect of matter on the metric properties of space must go to one of them.

  8. A study of non-homogeneous absorbing Markov chains

    E-Print Network [OSTI]

    Bean, John Kevin

    1975-01-01T23:59:59.000Z

    A STUDY OF NON-HOMOGENEOUS ABSORBING MARKOV CHAINS A Thesis by JOHN KEVIN BEAN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement. ior the degree of MASTER OF SCIFNCE December 1975 Major... Subject: Mathematics A STUDY OF NON-HOMOGENEOUS ABSORBING MARKOV CHAINS A Thesis by JOHN KEVIN BEAN Approved as to style and content by: (C airman of Committee) (Head of Department) , '-. ! ember) em er December 1975 ABSTRACT A Study of Non...

  9. Theoretical/Computational Tools for Energy-Relevant Catalysis | The Ames

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin Transition in theTheoretical Study on Catalysis by

  10. An Empirical Model for Heterogeneous Translucent Objects

    E-Print Network [OSTI]

    Durand, Frédo

    scatter- ing in heterogeneous translucent objects. Motivated by the exponential fall-off of scattered in the marble example (Figure 3). Figure 3: The marble example. Left: Modulation texture and diffusely lit

  11. Dynamical Heterogeneities in Grains and Foams

    E-Print Network [OSTI]

    Olivier Dauchot; Douglas J. Durian; Martin van Hecke

    2010-10-05T23:59:59.000Z

    Dynamical heterogeneities have been introduced in the context of the glass transition of molecular liquids and the lengthscale associated with them has been argued to be at the origin of the observed quasi-universal behaviour of glassy systems. Dense amorphous packings of granular media and foams also exhibit slow dynamics, intermittency and heterogeneities. We review a number of recent experimental studies of these systems, where one has direct access to the relevant space-time dynamics, allowing for direct visualisations of the dynamical heterogeneities. On one hand these visualisations provide a unique opportunity to access the microscopic mechanisms responsible for the growth of dynamical correlations. On the other hand focussing on the differences in these heterogeneities in microscopically different systems allows to discuss the range of the analogies between molecular thermal glasses and athermal glasses such as granular media and foams. Finally this review is the opportunity to discuss various approaches to actually extract quantitatively the dynamical lengthscale from experimental data.

  12. Homogeneous blue pattern: A rare presentation in an acral congenital melanocytic nevus

    E-Print Network [OSTI]

    2010-01-01T23:59:59.000Z

    Malvehy J. Homogeneous blue pattern in an acral congenitalof a plantar combined blue nevus: a simulator of melanoma.Homogeneous blue pattern: A rare presentation in an acral

  13. Heterogeneous Recycling in Fast Reactors

    SciTech Connect (OSTI)

    Forget, Benoit; Pope, Michael; Piet, Steven J.; Driscoll, Michael

    2012-07-30T23:59:59.000Z

    Current sodium fast reactor (SFR) designs have avoided the use of depleted uranium blankets over concerns of creating weapons grade plutonium. While reducing proliferation risks, this restrains the reactor design space considerably. This project will analyze various blanket and transmutation target configurations that could broaden the design space while still addressing the non-proliferation issues. The blanket designs will be assessed based on the transmutation efficiency of key minor actinide (MA) isotopes and also on mitigation of associated proliferation risks. This study will also evaluate SFR core performance under different scenarios in which depleted uranium blankets are modified to include minor actinides with or without moderators (e.g. BeO, MgO, B4C, and hydrides). This will be done in an effort to increase the sustainability of the reactor and increase its power density while still offering a proliferation resistant design with the capability of burning MA waste produced from light water reactors (LWRs). Researchers will also analyze the use of recycled (as opposed to depleted) uranium in the blankets. The various designs will compare MA transmutation efficiency, plutonium breeding characteristics, proliferation risk, shutdown margins and reactivity coefficients with a current reference sodium fast reactor design employing homogeneous recycling. The team will also evaluate the out-of-core accumulation and/or burn-down rates of MAs and plutonium isotopes on a cycle-by-cycle basis. This cycle-by-cycle information will be produced in a format readily usable by the fuel cycle systems analysis code, VISION, for assessment of the sustainability of the deployment scenarios.

  14. Classification of Message Spreading in a Heterogeneous Social Network

    E-Print Network [OSTI]

    Jendoubi, Siwar; Liétard, Ludovic; Yaghlane, Boutheina Ben

    2015-01-01T23:59:59.000Z

    Nowadays, social networks such as Twitter, Facebook and LinkedIn become increasingly popular. In fact, they introduced new habits, new ways of communication and they collect every day several information that have different sources. Most existing research works fo-cus on the analysis of homogeneous social networks, i.e. we have a single type of node and link in the network. However, in the real world, social networks offer several types of nodes and links. Hence, with a view to preserve as much information as possible, it is important to consider so-cial networks as heterogeneous and uncertain. The goal of our paper is to classify the social message based on its spreading in the network and the theory of belief functions. The proposed classifier interprets the spread of messages on the network, crossed paths and types of links. We tested our classifier on a real word network that we collected from Twitter, and our experiments show the performance of our belief classifier.

  15. Proton Mediated Chemistry and Catalysis in a Self-Assembled Supramolecular Host

    SciTech Connect (OSTI)

    Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2009-04-10T23:59:59.000Z

    Synthetic supramolecular host assemblies can impart unique reactivity to encapsulated guest molecules. Synthetic host molecules have been developed to carry out complex reactions within their cavities, despite the fact that they lack the type of specifically tailored functional groups normally located in the analogous active sites of enzymes. Over the past decade, the Raymond group has developed a series of self-assembled supramolecules and the Bergman group has developed and studied a number of catalytic transformations. In this Account, we detail recent collaborative work between these two groups, focusing on chemical catalysis stemming from the encapsulation of protonated guests and expanding to acid catalysis in basic solution. We initially investigated the ability of a water-soluble, self-assembled supramolecular host molecule to encapsulate protonated guests in its hydrophobic core. Our study of encapsulated protonated amines revealed rich host-guest chemistry. We established that self-exchange (that is, in-out guest movement) rates of protonated amines were dependent on the steric bulk of the amine rather than its basicity. The host molecule has purely rotational tetrahedral (T) symmetry, so guests with geminal N-methyl groups (and their attendant mirror plane) were effectively desymmetrized; this allowed for the observation and quantification of the barriers for nitrogen inversion followed by bond rotation. Furthermore, small nitrogen heterocycles, such as N-alkylaziridines, N-alkylazetidines, and N-alkylpyrrolidines, were found to be encapsulated as proton-bound homodimers or homotrimers. We further investigated the thermodynamic stabilization of protonated amines, showing that encapsulation makes the amines more basic in the cavity. Encapsulation raises the effective basicity of protonated amines by up to 4.5 pK{sub a} units, a difference almost as large as that between the moderate and strong bases carbonate and hydroxide. The thermodynamic stabilization of protonated guests was translated into chemical catalysis by taking advantage of the potential for accelerating reactions that take place via positively charged transition states, which could be potentially stabilized by encapsulation. Orthoformates, generally stable in neutral or basic solution, were found to be suitable substrates for catalytic hydrolysis by the assembly. Orthoformates small enough to undergo encapsulation were readily hydrolyzed by the assembly in basic solution, with rate acceleration factors up to 3900 compared with those of the corresponding uncatalyzed reactions. Furthering the analogy to enzymes that obey Michaelis-Menten kinetics, we observed competitive inhibition with the inhibitor NPr{sub 4}{sup +}, thereby confirming that the interior cavity of the assembly was the active site for catalysis. Mechanistic studies revealed that the assembly is required for catalysis and that the rate-limiting step of the reaction involves proton transfer from hydronium to the encapsulated substrate. Encapsulation in the assembly changes the orthoformate hydrolysis from an A-1 mechanism (in which decomposition of the protonated substrate is the rate-limiting step) to an A-S{sub E}2 mechanism (in which proton transfer is the rate-limiting step). The study of hydrolysis in the assembly was next extended to acetals, which were also catalytically hydrolyzed by the assembly in basic solution. Acetal hydrolysis changed from the A-1 mechanism in solution to an A-2 mechanism inside the assembly, where attack of water on the protonated substrate is rate limiting. This work provides rare examples of assembly-catalyzed reactions that proceed with substantial rate accelerations despite the absence of functional groups in the cavity and with mechanisms fully elucidated by quantitative kinetic studies.

  16. Applied Catalysis A: General 467 (2013) 559567 Contents lists available at ScienceDirect

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    Keywords: Aqueous solution growth Pulsed laser deposition Seed layer ZnO Nanowires Photocatalysis-hazardous oxidants and UV and/or visible light input. Heterogeneous photocatalysis is attracting extensive interest

  17. General basic and coordination catalysis in reactions of haloaromatic compounds with ammonia in the presence of copper(I) compounds

    SciTech Connect (OSTI)

    Chumak, V.T.; Shein, S.M.

    1985-11-01T23:59:59.000Z

    This paper presents a study made to detect general basic catalysis by ammonia (reagent) in reactions of ammonolysis of haloaromatic compounds in the presence of Cu/sup +/ ions, as well as to determine the generality of the mechanisms of the catalytic replacement of a halogen atom by an amino group in the anthraquinone and benzene series.

  18. Effects of catalysis on particle motion in plane-parallel and cylindrical channels in a catalytic reactor

    SciTech Connect (OSTI)

    Kabanov, A.N.; Murashkevich, F.I.; Shulimanova, Z.L.; Shukin, E.R.

    1987-09-01T23:59:59.000Z

    A theoretical study is made on aerosol behavior in a catalysis zone for a plane-parallel or cylindrical channel in a catalytic reactor. It is found that the thermophoretic trapping coefficient may attain 10-15% in a laminar flow having longitudinal Pe and Re >> 1 even for small relative temperature differences.

  19. Decarboxylative Arylation of Amino Acids via Photoredox Catalysis: A One-Step Conversion of Biomass to Drug

    E-Print Network [OSTI]

    MacMillan, David W. C.

    Decarboxylative Arylation of Amino Acids via Photoredox Catalysis: A One-Step Conversion of Biomass. This method offers rapid entry to prevalent benzylic amine architectures from an abundant biomass the worldwide abundance of biomass6 that incorporates carboxylate functionality (e.g., amino acids, -hydroxy

  20. Approved Module Information for CH3010, 2014/5 Module Title/Name: Catalysis Module Code: CH3010

    E-Print Network [OSTI]

    Neirotti, Juan Pablo

    Approved Module Information for CH3010, 2014/5 Module Title/Name: Catalysis Module Code: CH3010 School: Engineering and Applied Science Module Type: Standard Module New Module? No Module Credits: 10 in which available: BSc/MChem Applied Chemistry. BSc/MChem Chemistry. BEng/MEng Chemical Engineering. MEng

  1. Structure of Human Epoxide Hydrolase Reveals Mechanistic Inferences on Bifunctional Catalysis in Epoxide and Phosphate Ester Hydrolysis,

    E-Print Network [OSTI]

    Hammock, Bruce D.

    is unclear. Recent experiments demonstrate that the N-terminal domain of human sEH catalyzes the metalStructure of Human Epoxide Hydrolase Reveals Mechanistic Inferences on Bifunctional Catalysis ReceiVed February 4, 2004 ABSTRACT: The X-ray crystal structure of human soluble epoxide hydrolase (s

  2. Applied Catalysis A: General 219 (2001) 215222 Structural analysis of unpromoted Fe-based FischerTropsch

    E-Print Network [OSTI]

    Iglesia, Enrique

    2001-01-01T23:59:59.000Z

    Applied Catalysis A: General 219 (2001) 215­222 Structural analysis of unpromoted Fe-based Fischer­Tropsch by Mössbauer emission and X-ray absorption spectroscopies after use in the Fischer­Tropsch synthesis (FTS reactant mixture. © 2001 Elsevier Science B.V. All rights reserved. Keywords: Fischer­Tropsch synthesis; X

  3. Variable valve timing in a homogenous charge compression ignition engine

    DOE Patents [OSTI]

    Lawrence, Keith E.; Faletti, James J.; Funke, Steven J.; Maloney, Ronald P.

    2004-08-03T23:59:59.000Z

    The present invention relates generally to the field of homogenous charge compression ignition engines, in which fuel is injected when the cylinder piston is relatively close to the bottom dead center position for its compression stroke. The fuel mixes with air in the cylinder during the compression stroke to create a relatively lean homogeneous mixture that preferably ignites when the piston is relatively close to the top dead center position. However, if the ignition event occurs either earlier or later than desired, lowered performance, engine misfire, or even engine damage, can result. The present invention utilizes internal exhaust gas recirculation and/or compression ratio control to control the timing of ignition events and combustion duration in homogeneous charge compression ignition engines. Thus, at least one electro-hydraulic assist actuator is provided that is capable of mechanically engaging at least one cam actuated intake and/or exhaust valve.

  4. A generalized 2D pencil beam scaling algorithm for proton dose calculation in heterogeneous slab geometries

    SciTech Connect (OSTI)

    Westerly, David C. [Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States); Mo Xiaohu; DeLuca, Paul M. Jr. [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705 (United States); Tome, Wolfgang A. [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705 and Institute of Onco-Physics, Albert Einstein College of Medicine and Division of Medical Physics, Department of Radiation Oncology, Montefiore Medical Center, Bronx, New York 10461 (United States); Mackie, Thomas R. [Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53705 and Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53792 (United States)

    2013-06-15T23:59:59.000Z

    Purpose: Pencil beam algorithms are commonly used for proton therapy dose calculations. Szymanowski and Oelfke ['Two-dimensional pencil beam scaling: An improved proton dose algorithm for heterogeneous media,' Phys. Med. Biol. 47, 3313-3330 (2002)] developed a two-dimensional (2D) scaling algorithm which accurately models the radial pencil beam width as a function of depth in heterogeneous slab geometries using a scaled expression for the radial kernel width in water as a function of depth and kinetic energy. However, an assumption made in the derivation of the technique limits its range of validity to cases where the input expression for the radial kernel width in water is derived from a local scattering power model. The goal of this work is to derive a generalized form of 2D pencil beam scaling that is independent of the scattering power model and appropriate for use with any expression for the radial kernel width in water as a function of depth. Methods: Using Fermi-Eyges transport theory, the authors derive an expression for the radial pencil beam width in heterogeneous slab geometries which is independent of the proton scattering power and related quantities. The authors then perform test calculations in homogeneous and heterogeneous slab phantoms using both the original 2D scaling model and the new model with expressions for the radial kernel width in water computed from both local and nonlocal scattering power models, as well as a nonlocal parameterization of Moliere scattering theory. In addition to kernel width calculations, dose calculations are also performed for a narrow Gaussian proton beam. Results: Pencil beam width calculations indicate that both 2D scaling formalisms perform well when the radial kernel width in water is derived from a local scattering power model. Computing the radial kernel width from a nonlocal scattering model results in the local 2D scaling formula under-predicting the pencil beam width by as much as 1.4 mm (21%) at the depth of the Bragg peak for a 220 MeV proton beam in homogeneous water. This translates into a 32% dose discrepancy for a 5 mm Gaussian proton beam. Similar trends were observed for calculations made in heterogeneous slab phantoms where it was also noted that errors tend to increase with greater beam penetration. The generalized 2D scaling model performs well in all situations, with a maximum dose error of 0.3% at the Bragg peak in a heterogeneous phantom containing 3 cm of hard bone. Conclusions: The authors have derived a generalized form of 2D pencil beam scaling which is independent of the proton scattering power model and robust to the functional form of the radial kernel width in water used for the calculations. Sample calculations made with this model show excellent agreement with expected values in both homogeneous water and heterogeneous phantoms.

  5. CT-scan-monitored electrical-resistivity measurements show problems achieving homogeneous saturation

    SciTech Connect (OSTI)

    Sprunt, E.S.; Davis, R.M.; Muegge, E.L. (Mobil R and D Corp. (US)); Desai, K.P. (Saudi Aramco (SA))

    1991-06-01T23:59:59.000Z

    This paper reports on x-ray computerized tomography (CT) scans obtained during measurement of the electrical resistivity of core samples which revealed some problems in obtaining uniform saturation along the lengths of the samples. The electrical resistivity of core samples is measured as a function of water saturation to determine the saturation exponent used in electric-log interpretation. An assumption in such tests is that the water saturation is uniformly distributed. Failure of this assumption can result in errors in the determination of the saturation exponent. Three problems were identified in obtaining homogeneous water saturation in two samples of a Middle Eastern carbonate grainstone: a stationary front formed in one sample at 1-psi oil/brine capillary pressure, a moving front formed at oil/brine capillary pressure {le}4 psi in samples tested in fresh mixed-wettability and cleaned water-wet states, and the heterogeneous fluid distribution caused by a rapidly moving front did not dissipate when the capillary pressure was eliminated in the samples.

  6. Environment-based pin-power reconstruction method for homogeneous core calculations

    SciTech Connect (OSTI)

    Leroyer, H.; Brosselard, C.; Girardi, E. [EDF R and D/SINETICS, 1 av du General de Gaulle, F92141 Claman Cedex (France)

    2012-07-01T23:59:59.000Z

    Core calculation schemes are usually based on a classical two-step approach associated with assembly and core calculations. During the first step, infinite lattice assemblies calculations relying on a fundamental mode approach are used to generate cross-sections libraries for PWRs core calculations. This fundamental mode hypothesis may be questioned when dealing with loading patterns involving several types of assemblies (UOX, MOX), burnable poisons, control rods and burn-up gradients. This paper proposes a calculation method able to take into account the heterogeneous environment of the assemblies when using homogeneous core calculations and an appropriate pin-power reconstruction. This methodology is applied to MOX assemblies, computed within an environment of UOX assemblies. The new environment-based pin-power reconstruction is then used on various clusters of 3x3 assemblies showing burn-up gradients and UOX/MOX interfaces, and compared to reference calculations performed with APOLLO-2. The results show that UOX/MOX interfaces are much better calculated with the environment-based calculation scheme when compared to the usual pin-power reconstruction method. The power peak is always better located and calculated with the environment-based pin-power reconstruction method on every cluster configuration studied. This study shows that taking into account the environment in transport calculations can significantly improve the pin-power reconstruction so far as it is consistent with the core loading pattern. (authors)

  7. Design, Synthesis and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

    SciTech Connect (OSTI)

    Akio Ishikawa; Manuel Ojeda; Nan Yao; Enrique Iglesia

    2007-03-31T23:59:59.000Z

    This project extends previously discovered Fe-based catalysts to hydrogen-poor synthesis gas streams derived from coal and biomass sources. These catalysts have shown unprecedented Fischer-Tropsch synthesis rates and selectivities for synthesis gas derived from methane. During the first reporting period, we certified a microreactor, installed required analytical equipment, and reproduced synthetic protocols and catalytic results previously reported. During the second reporting period, we prepared several Fe-based compositions for Fischer-Tropsch Synthesis and tested the effects of product recycle under both subcritical and supercritical conditions. During the third and fourth reporting periods, we improved the catalysts preparation method, which led to Fe-based materials with the highest FTS reaction rates and selectivities so far reported, a finding that allowed their operation at lower temperatures and pressures with high selectivity to desired products (C{sub 5+}, olefins). During the fifth and sixth reporting period, we studied the effects of different promoters on catalytic performance, specifically how their sequence of addition dramatically influenced the performance of these materials in the Fischer-Tropsch synthesis. We also continued our studies of the kinetic behavior of these materials during the sixth reporting period. Specifically, the effects of H{sub 2}, CO, and CO{sub 2} on the rates and selectivities of Fischer-Tropsch Synthesis reactions led us to propose a new sequence of elementary steps on Fe and Co Fischer-Tropsch catalysts. Finally, we also started a study of the use of colloidal precipitation methods for the synthesis small Co clusters using recently developed methods to explore possible further improvements in FTS rates and selectivities. We found that colloidal synthesis makes possible the preparation of small cobalt particles, although large amount of cobalt silicate species, which are difficult to reduce, were formed. During this seventh reporting period, we have explored several methods to modify the silanol groups on SiO{sub 2} by using either a homogeneous deposition-precipitation method or surface titration of Si-OH on SiO{sub 2} with zirconium (IV) ethoxide to prevent the formation of unreducible and unreactive CoO{sub x} species during synthesis and FTS catalysis. We have synthesized monometallic Co/ZrO{sub 2}/SiO{sub 2} catalysts with different Co loadings (11-20 wt%) by incipient wetness impregnation methods and characterized the prepared Co supported catalysts by H{sub 2} temperature-programmed reduction (H{sub 2}-TPR) and H{sub 2}-chemisorption. We have measured the catalytic performance in FTS reactions and shown that although the hydroxyl groups on the SiO{sub 2} surface are difficult to be fully titrated by ZrO{sub 2}, modification of ZrO{sub 2} on SiO{sub 2} surface can improve the Co clusters dispersion and lead to a larger number of exposed Co surface atoms after reduction and during FTS reactions. During this seventh reporting period, we have also advanced our development of the reaction mechanism proposed in the previous reporting period. Specifically, we have shown that our novel proposal for the pathways involved in CO activation on Fe and Co catalysts is consistent with state-of-the-art theoretical calculations carried out in collaboration with Prof. Manos Mavrikakis (University of Wisconsin-Madison). Finally, we have also worked on the preparation of several manuscripts describing our findings about the preparation, activation and mechanism of the FTS with Fe-based catalysts and we have started redacting the final report for this project.

  8. MESOSCALE MODELLING OF WIND ENERGY OVER NON-HOMOGENEOUS TERRAIN

    E-Print Network [OSTI]

    Pielke, Roger A.

    MESOSCALE MODELLING OF WIND ENERGY OVER NON-HOMOGENEOUS TERRAIN (ReviewArticle) Y. MAHRER.1. OBSERVATIONALAPPROACHES Evaluations of wind energy based on wind observations (usually surface winds) at well, the resolution of the wind energy pattern throughout an extended area by this methodology requires a large number

  9. Homogenized Maxwell's Equations; a Model for Varistor Ceramics

    E-Print Network [OSTI]

    Birnir, Björn

    from [3] of the electric field as a function of the current density for Zinc Oxide, ZnHomogenized Maxwell's Equations; a Model for Varistor Ceramics Bj¨orn Birnir Niklas Wellander and lower bounds are obtained for the effective conductivity in the varistor. These two bounds

  10. Homogenized Maxwell's Equations; a Model for Varistor Ceramics

    E-Print Network [OSTI]

    Birnir, Björn

    from [3] of the electric field as a function of the current density for Zinc Oxide, ZnHomogenized Maxwell's Equations; a Model for Varistor Ceramics BjË? orn Birnir Niklas Wellander and lower bounds are obtained for the effective conductivity in the varistor. These two bounds

  11. Anisotropic Homogeneous Cosmologies in the Post-Newtonian Approximation

    E-Print Network [OSTI]

    Tamath Rainsford

    2000-07-23T23:59:59.000Z

    In this paper we explore how far the post-Newtonian theory goes in overcoming the difficulties associated with anisotropic homogeneous cosmologies in the Newtonian approximation. It will be shown that, unlike in the Newtonian case, the cosmological equations of the post-Newtonian approximation are much more in the spirit of general relativity with regard to the nine Bianchi types and issues of singularities. The situations of vanishing rotation and vanishing shear are treated separately. The homogeneous Bianchi I model is considered as an example of a rotation-free cosmology with anisotropy. It is found in the Newtonian approximation that there are arbitrary functions that need to be given for all time if the initial value problem is to be well-posed, while in the post-Newtonian case there is no such need. For the general case of a perfect fluid only the post-Newtonian theory can satisfactorily describe the effects of pressure. This is in accordance with findings in an earlier paper where the post-Newtonian approximation was applied to homogeneous cosmologies. For a shear-free anisotropic homogeneous cosmology the Newtonian theory of Heckmann and Sch\\"ucking is explored. Comparisons with its relativistic and post-Newtonian counterparts are made. In the Newtonian theory solutions exist to which there are no analogues in general relativity. The post-Newtonian approximation may provide a way out.

  12. CODIMENSION 2 CYCLES ON PRODUCTS OF PROJECTIVE HOMOGENEOUS SURFACES

    E-Print Network [OSTI]

    * *ary field F reduces to computing its torsion subgroup. For codimension d 1, the Chow group CH d provide general bounds for the torsion* * in the codi- mension 2 Chow groups of the products of projective homogeneous surfaces* *. In particular, we determine the torsion for the product of four

  13. Preparation of Lead Zirconate by Homogeneous Precipitation and Calcination

    E-Print Network [OSTI]

    Tas, A. Cuneyt

    Preparation of Lead Zirconate by Homogeneous Precipitation and Calcination Ersin Emre Oren, Ercan. Introduction LEAD ZIRCONATE (PbZrO3) is an antiferroelectric ceramic with a Curie temperature of 230°C electric field to the ceramic in the antifer- roelectric state) leads to significant energy storage

  14. Correlation between homogeneous propane pyrolysis and pyrocarbon deposition

    E-Print Network [OSTI]

    Boyer, Edmond

    Correlation between homogeneous propane pyrolysis and pyrocarbon deposition C´edric Descamps, G propane pyrolysis is studied in a 1-D hot-wall CVD furnace. The gas-phase pyrolysis is modelled in previous reports [6]: total pressure equal to 2 kPa, temperature between 900 K and 1400 K, and pure propane

  15. Lifetime Benefits through Load Balancing in Homogeneous Sensor Networks

    E-Print Network [OSTI]

    Haenggi, Martin

    , battery depletion is emulated so that it becomes possible to actually measure the load balancingLifetime Benefits through Load Balancing in Homogeneous Sensor Networks Daniele Puccinelli network. The use of load balancing schemes can be expected to provide significant lifetime benefits

  16. Homogeneous Charge Compression Ignition: Formulation Effect of a Diesel Fuel

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Homogeneous Charge Compression Ignition: Formulation Effect of a Diesel Fuel on the Initiation and the Combustion Potential of Olefin Impact in a Diesel Base Fuel D. Alseda1,2, X. Montagne1 and P. Dagaut2 1 Compression Ignition: Formulation Effect of a Diesel Fuel on the Initiation and the Combustion - Potential

  17. Asymmetry of rotational catalysis of single membrane-bound F0F1-ATP synthase

    E-Print Network [OSTI]

    Zarrabi, Nawid; Diez, Manuel; Graeber, Peter; Wrachtrup, Joerg; Boersch, Michael

    2007-01-01T23:59:59.000Z

    Synthesis of the cellular 'energy currency' ATP is catalyzed by membrane-bound F0F1-ATP synthases. The chemical reaction at three binding sites in the F1 part is coupled to proton translocation through the membrane-integrated F0 part by an internal rotation of subunits. We examined the rotary movements of the epsilon-subunit of the 'rotor' with respect to the b-subunits of the 'stator' by single-molecule fluorescence resonance energy transfer (FRET). Rotation of epsilon during ATP hydrolysis is divided into three major steps with constant FRET level corresponding to three binding sites. Different catalytic activities of the individual binding sites were observed depending on the relative orientation of the 'rotor'. Computer simulations of the FRET signals and non-equally distributed orientations of epsilon strongly corroborate asymmetry of catalysis in F0F1-ATP synthase.

  18. Methane Oxidation to Methanol without CO2 Emission: Catalysis by Atomic Negative Ions

    E-Print Network [OSTI]

    Tesfamichael, Aron; Felfli, Zineb; Msezane, Alfred Z

    2014-01-01T23:59:59.000Z

    The catalytic activities of the atomic Y-, Ru-, At-, In-, Pd-, Ag-, Pt-, and Os- ions have been investigated theoretically using the atomic Au- ion as the benchmark for the selective partial oxidation of methane to methanol without CO2 emission. Dispersion-corrected density-functional theory has been used for the investigation. From the energy barrier calculations and the thermodynamics of the reactions, we conclude that the catalytic effect of the atomic Ag-, At-, Ru-, and Os- ions is higher than that of the atomic Au- ion catalysis of CH4 conversion to methanol. By controlling the temperature around 290K (Os-), 300K (Ag-), 310K (At-), 320K (Ru-) and 325K (Au-) methane can be completely oxidized to methanol without the emission of CO2. We conclude by recommending the investigation of the catalytic activities of combinations of the above negative ions for significant enhancement of the selective partial oxidation of methane to methanol.

  19. Superacid catalysis of light hydrocarbon conversion. Sixth quarterly report, January 1, 1995--March 31, 1995

    SciTech Connect (OSTI)

    Gates, B.C. [California Univ., Davis, CA (United States). Dept. of Chemical Engineering and Materials Science

    1995-08-01T23:59:59.000Z

    Iron- and Manganese-promoted sulfated zirconia is a catalyst for the conversion of propane, but the rate of conversion of propane is much less than the rate of conversion of butane. Whereas this catalyst appears to be a good candidate for practical, industrial conversion of butane, it appears to lack sufficient activity for practical conversion of propane. Perhaps more active catalysts will be useful for propane conversion. The propane conversion data reported here provide excellent insights into the chemistry of the catalytic conversions; they are consistent with the inference that the catalyst is a superacid and that the chemistry is analogous to. that determined in superacid solutions by G.A. Olah, who was awarded the most recent Nobel Prize in chemistry for his work. The catalyst was tested for conversion of propane at 1 bar, 200--300{degrees}C and propane partial pressures in the range of 0.01--0.05 bar. At 250{degrees}C, catalysis was demonstrated, as the number of propane molecules converted was at least 1 per sulfate group after 16 days of operation in a continues flow reactor. Propane was converted in high yield to butanes, but the conversions were low, for example being only a fraction of a percent at a space velocity of 9.1 {times} 10{sup {minus}7} mol(g of catalysis {center_dot} s) and 250{degrees}C. Coke formation was rapid. The observation of butanes, pentanes, and methane as products is consistent with Olah superacid chemistry, whereby propane is first protonated by a very strong acid to form a carbonium ion. The carbonium ion then decomposes into methane and an ethyl cation which undergoes oligocondensation reactions with propane to form higher molecular weight alkanes. The results are consistent with the identification of iron- and manganese-promoted sulfated zirconia as a superacid.

  20. Active particles in heterogeneous media display new physics: existence of optimal noise and absence of bands and long-range order

    E-Print Network [OSTI]

    Oleksandr Chepizhko; Fernando Peruani

    2015-03-18T23:59:59.000Z

    We present a detailed study of the large-scale collective properties of self-propelled particles (SPPs) moving in two-dimensional heterogeneous space. The impact of spatial heterogeneities on the ordered, collectively moving phase is investigated. We show that for strong enough spatial heterogeneity, the well-documented high-density, high-ordered propagating bands that emerge in homogeneous space disappear. Moreover, the ordered phase does not exhibit long-range order, as occurs in homogeneous systems, but rather quasi-long range order: i.e. the SPP system becomes disordered in the thermodynamical limit. For finite size systems, we find that there is an optimal noise value that maximizes order. Interestingly, the system becomes disordered in two limits, for high noise values as well as for vanishing noise. This remarkable finding strongly suggests the existence of two critical points, instead of only one, associated to the collective motion transition. Density fluctuations are consistent with these observations, being higher and anomalously strong at the optimal noise, and decreasing and crossing over to normal for high and low noise values. Collective properties are investigated in static as well as dynamic heterogeneous environments, and by changing the symmetry of the velocity alignment mechanism of the SPPs.

  1. Mapping mesoscale heterogeneity in the plastic deformation of a copper single crystal

    E-Print Network [OSTI]

    Magid, K. R.

    2009-01-01T23:59:59.000Z

    619. page 18 Mapping mesoscale heterogeneity in a deformedthese planes. page 36 Mapping mesoscale heterogeneity in aJanuary 2009, 77–107 Mapping mesoscale heterogeneity in the

  2. Heterogeneous Temporal Probabilistic Agents JURGEN DIX

    E-Print Network [OSTI]

    Kraus, Sarit

    and software modules. We will define the concept of a heterogeneous temporal probabilistic (HTP) agent). Intuitively, an FTPSI specifies what all an HTP agent is permitted/forbidden/obliged to do at various times t. As changes occur in the environment, the HTP agent must compute a new FTPSI. HTP agents continuously compute

  3. Modeling the Energy Efficiency of Heterogeneous Clusters

    E-Print Network [OSTI]

    Teo, Yong-Meng

    are an alternative for energy-efficient clusters [18], [20], [23]. On the contrary, other researchersModeling the Energy Efficiency of Heterogeneous Clusters Lavanya Ramapantulu, Bogdan Marius Tudor analyze the energy efficiency of mixing high-performance and low-power nodes in a cluster. Using a model

  4. Chimera states in heterogeneous Kuramoto networks

    E-Print Network [OSTI]

    Laing, Carlo R.

    Chimera states in heterogeneous Kuramoto networks Carlo R. Laing IIMS, Massey University, Auckland discovered by Kuramoto c. 2002; named "chimeras" by Strogatz. #12;· Identical oscillators, so why coherent/incoherent groups? · This type of solution discovered by Kuramoto c. 2002; named "chimeras" by Strogatz. #12

  5. Heterogeneous lithium niobate photonics on silicon substrates

    E-Print Network [OSTI]

    Fathpour, Sasan

    Heterogeneous lithium niobate photonics on silicon substrates Payam Rabiei,1,* Jichi Ma,1 Saeed-confined lithium niobate photonic devices and circuits on silicon substrates is reported based on wafer bonding high- performance lithium niobate microring optical resonators and Mach- Zehnder optical modulators

  6. ON DIFFUSION IN HETEROGENEOUS MEDIA YOUXUE ZHANG*,

    E-Print Network [OSTI]

    Liu, Liping

    , heterogeneous media, multi-mineral rocks, multi-phase media, composite materials, kinetics, porous rocks to bulk diffusion, and porous materials (such as plants, soil, rock with partial melt or fluid, sediment of air and moisture in soils, drying of paint, wood, and concrete, diffusion of gases in rubber, movement

  7. Vancouver: A Software Stack for Productive Heterogeneous

    E-Print Network [OSTI]

    .S. Department of Energy Vetter_Vancouver_SC10 Vancouver overview · Large-scale heterogeneous system deployments #12;3 Managed by UT-Battelle for the U.S. Department of Energy Vetter_Vancouver_SC10 Language tools optimizations #12;4 Managed by UT-Battelle for the U.S. Department of Energy Vetter_Vancouver_SC10 Runtime data

  8. Semantic Taxonomy Induction from Heterogenous Evidence Computer Science Department

    E-Print Network [OSTI]

    Ng, Andrew Y.

    Semantic Taxonomy Induction from Heterogenous Evidence Rion Snow Computer Science Department­ tic taxonomies. Previous algorithms for taxonomy induction have typically focused on independent over heterogenous relationships to optimize the entire structure of the taxonomy, using knowl­ edge

  9. Semantic Taxonomy Induction from Heterogenous Evidence Computer Science Department

    E-Print Network [OSTI]

    Ng, Andrew Y.

    Semantic Taxonomy Induction from Heterogenous Evidence Rion Snow Computer Science Department- tic taxonomies. Previous algorithms for taxonomy induction have typically focused on independent over heterogenous relationships to optimize the entire structure of the taxonomy, using knowl- edge

  10. Communication Efficient Construction of Decision Trees Over Heterogeneously Distributed Data

    E-Print Network [OSTI]

    Kargupta, Hilol

    Communication Efficient Construction of Decision Trees Over Heterogeneously Distributed Data Chris Giannella Kun Liu Todd Olsen Hillol Kargupta Department of Computer Science and Electrical Engineering to efficiently construct a decision tree over heterogeneously distributed data with- out centralizing. We compare

  11. Characterization of oil and gas reservoir heterogeneity

    SciTech Connect (OSTI)

    Tyler, N.; Barton, M.D.; Bebout, D.G.; Fisher, R.S.; Grigsby, J.D.; Guevara, E.; Holtz, M.; Kerans, C.; Nance, H.S.; Levey, R.A.

    1992-10-01T23:59:59.000Z

    Research described In this report addresses the internal architecture of two specific reservoir types: restricted-platform carbonates and fluvial-deltaic sandstones. Together, these two reservoir types contain more than two-thirds of the unrecovered mobile oil remaining ill Texas. The approach followed in this study was to develop a strong understanding of the styles of heterogeneity of these reservoir types based on a detailed outcrop description and a translation of these findings into optimized recovery strategies in select subsurface analogs. Research targeted Grayburg Formation restricted-platform carbonate outcrops along the Algerita Escarpment and In Stone Canyon In southeastern New Mexico and Ferron deltaic sandstones in central Utah as analogs for the North Foster (Grayburg) and Lake Creek (Wilcox) units, respectively. In both settings, sequence-stratigraphic style profoundly influenced between-well architectural fabric and permeability structure. It is concluded that reservoirs of different depositional origins can therefore be categorized Into a heterogeneity matrix'' based on varying intensity of vertical and lateral heterogeneity. The utility of the matrix is that it allows prediction of the nature and location of remaining mobile oil. Highly stratified reservoirs such as the Grayburg, for example, will contain a large proportion of vertically bypassed oil; thus, an appropriate recovery strategy will be waterflood optimization and profile modification. Laterally heterogeneous reservoirs such as deltaic distributary systems would benefit from targeted infill drilling (possibly with horizontal wells) and improved areal sweep efficiency. Potential for advanced recovery of remaining mobile oil through heterogeneity-based advanced secondary recovery strategies In Texas is projected to be an Incremental 16 Bbbl. In the Lower 48 States this target may be as much as 45 Bbbl at low to moderate oil prices over the near- to mid-term.

  12. SU-E-I-100: Heterogeneity Studying for Primary and Lymphoma Tumors by Using Multi-Scale Image Texture Analysis with PET-CT Images

    SciTech Connect (OSTI)

    Li, Dengwang [Shandong Normal University, Jinan, Shandong Province (China); Wang, Qinfen [Shandong Normal University, Jinan, Shandong (China); Li, H; Chen, J [Shandong Cancer Hospital and Institute, Jinan, Shandong (China)

    2014-06-01T23:59:59.000Z

    Purpose: The purpose of this research is studying tumor heterogeneity of the primary and lymphoma by using multi-scale texture analysis with PET-CT images, where the tumor heterogeneity is expressed by texture features. Methods: Datasets were collected from 12 lung cancer patients, and both of primary and lymphoma tumors were detected with all these patients. All patients underwent whole-body 18F-FDG PET/CT scan before treatment.The regions of interest (ROI) of primary and lymphoma tumor were contoured by experienced clinical doctors. Then the ROI of primary and lymphoma tumor is extracted automatically by using Matlab software. According to the geometry size of contour structure, the images of tumor are decomposed by multi-scale method.Wavelet transform was performed on ROI structures within images by L layers sampling, and then wavelet sub-bands which have the same size of the original image are obtained. The number of sub-bands is 3L+1.The gray level co-occurrence matrix (GLCM) is calculated within different sub-bands, thenenergy, inertia, correlation and gray in-homogeneity were extracted from GLCM.Finally, heterogeneity statistical analysis was studied for primary and lymphoma tumor using the texture features. Results: Energy, inertia, correlation and gray in-homogeneity are calculated with our experiments for heterogeneity statistical analysis.Energy for primary and lymphomatumor is equal with the same patient, while gray in-homogeneity and inertia of primaryare 2.59595±0.00855, 0.6439±0.0007 respectively. Gray in-homogeneity and inertia of lymphoma are 2.60115±0.00635, 0.64435±0.00055 respectively. The experiments showed that the volume of lymphoma is smaller than primary tumor, but thegray in-homogeneity and inertia were higher than primary tumor with the same patient, and the correlation with lymphoma tumors is zero, while the correlation with primary tumor isslightly strong. Conclusion: This studying showed that there were effective heterogeneity differences between primary and lymphoma tumor by multi-scale image texture analysis. This work is supported by National Natural Science Foundation of China (No. 61201441), Research Fund for Excellent Young and Middle-aged Scientists of Shandong Province (No. BS2012DX038), Project of Shandong Province Higher Educational Science and Technology Program (No. J12LN23), Jinan youth science and technology star (No.20120109)

  13. Centrifugal cosmological repulsive force in a homogeneous universe

    E-Print Network [OSTI]

    A. V. Klimenko; V. A. Klimenko

    2011-03-21T23:59:59.000Z

    We study the dynamics of homogeneous isotropic three-dimensional worlds filled with radiation (3R-worlds). It is shown that the dynamics of these worlds with the additional fourth large-scale spatial dimension leads to an important effect. At 3R-worlds the forces of repulsion appear. The source of these forces is the thermal energy of the radiation that fills these worlds. In the four-dimensional space, these forces are centrifugal. They operate in an external for 3R-world spatial dimension and stretch it. In the three-dimensional comoving coordinate system the centrifugal forces shows themselves as forces of repulsion. Standard Einstein's equations do not describe these forces. Written generalized Einstein's equation describing the dynamics of a homogeneous isotropic universe, taking into consideration the centrifugal forces of repulsion. We propose a cosmological model of the universe, based on these equations. This model apply to explain the observation data.

  14. Apparatus for unilateral generation of a homogeneous magnetic field

    DOE Patents [OSTI]

    Fukushima, E.; Rath, A.R.; Roeder, S.B.W.

    1984-05-01T23:59:59.000Z

    An apparatus for unilaterally producing a substantially homogeneous magnetic field. The apparatus includes two circular electromagnet coils, a small coil and a large coil, which are coaxial with one another and which are separated by a distance equal to one-half the difference in the radius of the two coils. By appropriate selection of electrical currents, which are passed through the coils in opposite directions, a region of homogeneous magnetic field is formed. This region is centered on the common axis of the two coils, at a point on the axis which is at a distance from the small coil equal to one-half the radius of the small coil, and which is on the opposite side of the small coil from the large coil. The apparatus has particular application in the field of diagnostic medical NMR and other NMR applications.

  15. Apparatus for unilateral generation of a homogeneous magnetic field

    DOE Patents [OSTI]

    Fukushima, Eiichi (Los Alamos, NM); Rath, Alan R. (San Diego, CA); Roeder, Stephen B. W. (La Mesa, CA)

    1988-01-01T23:59:59.000Z

    An apparatus for unilaterally producing a substantially homogeneous magnetic field. The apparatus includes two circular electromagnet coils, a small coil and a large coil, which are coaxial with one another and which are separated by a distance equal to one-half the difference in the radius of the two coils. By appropriate selection of electrical currents, which are passed through the coil in opposite directions, a region of homogeneous magnetic field is formed. This region is centered on the common axis of the two coils, at a point on the axis which is at a distance from the small coil equal to one-half the radius of the small coil, and which is on the opposite side of the small coil from the large coil. The apparatus has particular application in the field of diagnostic medical NMR and other NMR applications.

  16. High load operation in a homogeneous charge compression ignition engine

    DOE Patents [OSTI]

    Duffy, Kevin P. (Metamora, IL); Kieser, Andrew J. (Morton, IL); Liechty, Michael P. (Chillicothe, IL); Hardy, William L. (Peoria, IL); Rodman, Anthony (Chillicothe, IL); Hergart, Carl-Anders (Peoria, IL)

    2008-12-23T23:59:59.000Z

    A homogeneous charge compression ignition engine is set up by first identifying combinations of compression ratio and exhaust gas percentages for each speed and load across the engines operating range. These identified ratios and exhaust gas percentages can then be converted into geometric compression ratio controller settings and exhaust gas recirculation rate controller settings that are mapped against speed and load, and made available to the electronic

  17. Dosimetry in Mammography: Average Glandular Dose Based on Homogeneous Phantom

    SciTech Connect (OSTI)

    Benevides, Luis A. [Naval Sea Systems Command,1333 Isaac Hull Avenue, Washington Navy Yard, DC 20376 (United States); Hintenlang, David E. [University of Florida, 202 Nuclear Sciences Center, P.O. Box 1183, Gainesville Florida 32611 (United States)

    2011-05-05T23:59:59.000Z

    The objective of this study was to demonstrate that a clinical dosimetry protocol that utilizes a dosimetric breast phantom series based on population anthropometric measurements can reliably predict the average glandular dose (AGD) imparted to the patient during a routine screening mammogram. AGD was calculated using entrance skin exposure and dose conversion factors based on fibroglandular content, compressed breast thickness, mammography unit parameters and modifying parameters for homogeneous phantom (phantom factor), compressed breast lateral dimensions (volume factor) and anatomical features (anatomical factor). The patient fibroglandular content was evaluated using a calibrated modified breast tissue equivalent homogeneous phantom series (BRTES-MOD) designed from anthropomorphic measurements of a screening mammography population and whose elemental composition was referenced to International Commission on Radiation Units and Measurements Report 44 and 46 tissues. The patient fibroglandular content, compressed breast thickness along with unit parameters and spectrum half-value layer were used to derive the currently used dose conversion factor (DgN). The study showed that the use of a homogeneous phantom, patient compressed breast lateral dimensions and patient anatomical features can affect AGD by as much as 12%, 3% and 1%, respectively. The protocol was found to be superior to existing methodologies. The clinical dosimetry protocol developed in this study can reliably predict the AGD imparted to an individual patient during a routine screening mammogram.

  18. ORIGINAL RESEARCH PAPER Gridding heterogeneous bathymetric data sets with stacked

    E-Print Network [OSTI]

    Jakobsson, Martin

    heterogeneous bathymetric data sets for the compilation of Digital bathymetric models (DBMs), poses specific of the most widely used gridding methods, our approach yields superior DBMs based on heterogeneous bathymetric gridding algorithm has been specifically designed to con- struct DBMs from heterogeneous bathymetric source

  19. Design of heterogeneous turbine blade Xiaoping Qian, Deba Dutta*

    E-Print Network [OSTI]

    Qian, Xiaoping

    Design of heterogeneous turbine blade Xiaoping Qian, Deba Dutta* Department of Mechanical in turbine drivers push the material capabilities of turbine blades to the limit. The recent development of heterogeneous objects by layered manufacturing offers new potentials for the turbine blades. In heterogeneous

  20. September October November Samir Mitragotri

    E-Print Network [OSTI]

    Gray, Jeffrey J.

    the University of Florida has research interests that include Heterogeneous Catalysis, Nanoparticle Oxides

  1. Chinese Journal of Chemistry, 2009, 27, 1339--1344 Full Paper * E-mail: yiyuanpeng@yahoo.com

    E-Print Network [OSTI]

    Shen, Jun

    heterogeneous catalysis.5 However, these processes need rather harsh conditions such as high temperature

  2. CHEMICAL AND BIOMOLECULAR ENGINEERING 099. Undergraduate Research and Independent Study. (C) A maximum of 2 c.u. of CBE 099 may be applied toward

    E-Print Network [OSTI]

    Fang-Yen, Christopher

    and transition state theories. Heterogeneous catalysis. Electronic structure and properties of solids. 371

  3. Solubility and Aggregation of Charged Surfactants in Ionic Liquids Lang G. Chen and Harry Bermudez*

    E-Print Network [OSTI]

    of ILs are also of central importance in applications such as lubrication, (heterogeneous) catalysis

  4. Andrew T Storfer-Curriculum Vitae CURRICULUM VITAE

    E-Print Network [OSTI]

    Storfer, Andrew

    Synthesis Center (Catalysis Meeting) 2011-2014 "Heterogeneity in disease susceptibility of Tasmanian devils

  5. The Role of Interstitial Sites in the Ti3d Defect State

    E-Print Network [OSTI]

    , is used in a number of technological areas, includ- ing heterogeneous catalysis, photocatalysis, solar

  6. IMPACTS OF SOURCE TERM HETEROGENEITIES ON WATER PATHWAY DOSE.

    SciTech Connect (OSTI)

    SULLIVAN, T.; GUSKOV, A.; POSKAS, P.; RUPERTI, N.; HANUSIK, V.; ET AL.

    2004-09-15T23:59:59.000Z

    Radioactive sealed sources are used extensively throughout the world in different field and various activities such as medicine, agriculture, industry, research, education military applications, as well as nuclear facilities. The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation sources [1] defines a sealed source as ''radioactive material that is (a) permanently sealed in capsule or (b) closely bounded and in a solid form. The capsule or material of sealed source shall be strong enough to maintain remain leak free under the conditions of use and wear for which the source was designed, also under foreseeable mishaps''. When a radioactive sealed source is no longer needed, or becomes unfit for the intended application it is considered spent. A spent sealed source is not necessarily a waste because it can be used in other applications. If for any technical or economic reason (decay, obsolete equipment and technique, worn out equipment) no further use is foreseen, the spent sealed source is considered spent and becomes radioactive waste [2] [3]. In addition, a source may be taken out of service temporarily or indefinitely. In this case the source is out of used (''disused'') but not considered spent [4]. Sources that are not in active use and have not being declared as spent are considered as disused sealed sources [4]. Considering the potential radiation hazards associated with such waste it has to be managed and disposed of in a way that will ensure that the potential radiation hazards are adequately managed and controlled in compliance with the appropriate safety principles and criteria. It is recognized that there exists today experience and means for all steps in the management of disused sealed sources, except disposal of [2]. In many countries, disused sealed sources represent a part of the radioactive waste inventory being characterized generally with high specific activities and small physical sizes and for which a solution has to be found in term of long-term disposal. Together with their casing and packaging, they are one form of heterogeneous waste; many other forms of waste with heterogeneous properties exist. They may arise in very small quantities and with very specific characteristics in the case of small producers, or in larger streams with standard characteristics in others. This wide variety of waste induces three main different levels of waste heterogeneity: (1) hot spot (e.g. disused sealed sources); (2) large item inside a package (e.g. metal components); and (3) very large items to be disposed of directly in the disposal unit (e.g. irradiated pipes, vessels). Safety assessments generally assume a certain level of waste homogeneity in most of the existing or proposed disposal facilities. There is a need to evaluate the appropriateness of such an assumption and the influence on the results of safety assessment. This need is especially acute in the case of sealed sources. There are many cases where are storage conditions are poor, or there is improper management leading to a radiological accident, some with significant or detrimental impacts. Disposal in a near surface disposal facility has been used in the past for some disused sealed sources. This option is currently in use for others sealed sources, or is being studied for the rest of them. The regulatory framework differs greatly between countries. In some countries, large quantities of disused sealed sources have been disposed of without any restriction, in others their disposal is forbidden by law. In any case, evaluation of the acceptability of disposal of disused sealed sources in near surface disposal facility is of utmost importance.

  7. Kinetics of oxidation of an organic amine with a Cr(V) salen complex in homogeneous aqueous solution and on the surface of mesoporous silica

    SciTech Connect (OSTI)

    Szajna-Fuller, Ewa; Huang, Yulin; Rapp, Jennifer L.; Chaka, Gezhegn; Lin, Victor S.Y.; Pruski, Marek; Bakac, Andreja

    2009-03-09T23:59:59.000Z

    A comparative study of catalytic activity under homogeneous and heterogeneous conditions was carried out using the (salen)Cr{sup III}-catalyzed oxidation of tetramethylbenzidine (TMB) with iodosobenzene as a model reaction. Amine-functionalized mesoporous silica nanoparticles (MSN) were synthesized in a co-condensation reaction and functionalized with salen via a covalent Si-C bond. A Cr(III) complex of this supported ligand, MSN-(salen)Cr{sup III}, was prepared and characterized. Data from powder XRD, BET isotherms and BJH pore size distribution all showed that MSN-(salen)Cr{sup III} still had the typical MSN high surface area, narrow pore size distribution, and ordered hexagonal pore structure, which were further confirmed by transmission electron microscopy (TEM) images. {sup 13}C and {sup 29}Si solid-state NMR data provided structural information about the catalyst and verified successful functionalization of the salen ligand and coordination to Cr(III). No unreacted salen or Cr(III) were observed. The loadings of salen and salen-Cr{sup III} complex were determined via TGA and EDX, respectively. Both measurements indicated that approximately 0.5 mmol/g of catalyst was loaded on the surface of MSN. The oxidation of TMB with iodosobenzene using MSN-(salen)Cr{sup III} as a heterogeneous catalyst exhibited both similarities and differences with the analogous homogeneous reaction using (salen)Cr{sup III}(H{sub 2}O){sup +} as a catalyst in aqueous acetonitrile. In the presence of 0.10 M HClO{sub 4}, the two catalytic reactions proceeded at similar rates and generated the doubly oxidized product TMB{sup 2+}. In the absence of acid, the radical cation TMB{sup +} was produced. The kinetics of the heterogeneous reaction in the absence of added acid responded to concentrations of all three reagents, i.e. (salen)Cr{sup III}, TMB, and PhIO.

  8. Final Report: Experimental and Theoretical Studies of Surface Oxametallacycles - Connections to Heterogeneous Olefin Epoxidation

    SciTech Connect (OSTI)

    Mark A. Barteau

    2009-09-15T23:59:59.000Z

    This project has aimed at the rational design of catalysts for direct epoxidation of olefins. This chemistry remains one of the most challenging problems in heterogeneous catalysis. Although the epoxidation of ethylene by silver catalysts to form ethylene oxide (EO) has been practiced for decades, little progress has been made in expanding this technology to other products and processes. We have made significant advances through the combination of surface science experiments, Density Functional Theory (DFT) calculations, and catalytic reactor experiments, toward understanding the mechanism of this reaction on silver catalysts, and to the rational improvement of selectivity. The key has been our demonstration of surface oxametallacycle intermediates as the species that control reaction selectivity. This discovery permits the influence of catalyst promoters on selectivity to be probed, and new catalyst formulations to be developed. It also guides the development of new chemistry with potential for direct epoxidation of more complex olefins. During the award period we have focused on 1. the formation and reaction selectivity of complex olefin epoxides on silver surfaces, and 2. the influence of co-adsorbed oxygen atoms on the reactions of surface oxametallacycles on silver, and 3. the computational prediction, synthesis, characterization and experimental evaluation of bimetallic catalysts for ethylene epoxidation. The significance of these research thrusts is as follows. Selective epoxidation of olefins more complex than ethylene requires suppression of not only side reactions available to the olefin such as C-H bond breaking, but it requires formation and selective ring closure of the corresponding oxametallacycle intermediates. The work carried out under this grant has significantly advanced the field of catalyst design from first principles. The combination of computational tools, surface science, and catalytic reactor experiments in a single laboratory has few other examples. We have successfully predicted and validated new bimetallic catalyst for ethylene epoxidation. In so doing, we have established one of the first examples of successful catalyst design from first principles to achieve improved reaction selectivity.

  9. Mesoporous Silica Nanomaterials for Applications in Catalysis, Sensing, Drug Delivery and Gene Transfection

    SciTech Connect (OSTI)

    Daniela Rodica Radu

    2005-12-19T23:59:59.000Z

    The central theme of this dissertation is represented by the versatility of mesoporous silica nanomaterials in various applications such as catalysis and bio-applications, with main focus on biological applications of Mesoporous Silica Nanospheres (MSN). The metamorphosis that we impose to these materials from catalysis to sensing and to drug and gene delivery is detailed in this dissertation. First, we developed a synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pores surface of MSN by exploiting electrostatic and size matching between the cationic alkylammonium head group of the cetyltrimethylammonium bromide (CTAB) surfactant and various anionic organoalkoxysilane precursors at the micelle-water interface in a base-catalyzed condensation reaction of silicate. Aiming nature imitation, we demonstrated the catalytic abilities of the MSNs, We utilized an ethylenediamine functional group for chelating Cu{sup 2+} as a catalytic functional group anchored inside the mesopores. Thus, a polyalkynylene-based conducting polymer (molecular wire) was synthesized within the Cu-functionalized MSNs silica catalyst. For sensing applications, we have synthesized a poly(lactic acid) coated mesoporous silica nanosphere (PLA-MSN) material that serves as a fluorescence sensor system for detection of amino-containing neurotransmitters in neutral aqueous buffer. We exploited the mesoporosity of MSNs for encapsulating pharmaceutical drugs. We examined bio-friendly capping molecules such as polyamidoamine dendrimers of generations G2 to G4, to prevent the drug leaching. Next, the drug delivery system employed MSNs loaded with Doxorubicin, an anticancer drug. The results demonstrated that these nano-Trojan horses have ability to deliver Doxorubicin to cancer cells and induce their death. Finally, to demonstrate the potential of MSN as an universal cellular transmembrane nanovehicle, we anchored positively charged dendrimers on the surface of MSN and utilize them to complex cationic DNA. The p-EGFP-CI gene-coated MSN nanocomposite was able to transfect cancer cell lines, such as human HeLa and CHO cancer cell lines. The gene carrier ability of MSNs was further proved by transfecting primary cells and cotransfecting of two different genes in cancer cell lines. In sum, MSN are versatile partners in several types of applications.

  10. Probing the Impact of the EchinT C-Terminal Domain on Structure and Catalysis

    SciTech Connect (OSTI)

    S Bardaweel; J Pace; T Chou; V Cody; C Wagner

    2011-12-31T23:59:59.000Z

    Histidine triad nucleotide binding protein (Hint) is considered as the ancestor of the histidine triad protein superfamily and is highly conserved from bacteria to humans. Prokaryote genomes, including a wide array of both Gram-negative bacteria and Gram-positive bacteria, typically encode one Hint gene. The cellular function of Hint and the rationale for its evolutionary conservation in bacteria have remained a mystery. Despite its ubiquity and high sequence similarity to eukaryote Hint1 [Escherichia coli Hint (echinT) is 48% identical with human Hint1], prokaryote Hint has been reported in only a few studies. Here we report the first conformational information on the full-length N-terminal and C-terminal residues of Hint from the E. coli complex with GMP. Structural analysis of the echinT-GMP complex reveals that it crystallizes in the monoclinic space group P2{sub 1} with four homodimers in the asymmetric unit. Analysis of electron density for both the N-terminal residues and the C-terminal residues of the echinT-GMP complex indicates that the loops in some monomers can adopt more than one conformation. The observation of conformational flexibility in terminal loop regions could explain the presence of multiple homodimers in the asymmetric unit of this structure. To explore the impact of the echinT C-terminus on protein structure and catalysis, we conducted a series of catalytic radiolabeling and kinetic experiments on the C-terminal deletion mutants of echinT. In this study, we show that sequential deletion of the C-terminus likely has no effect on homodimerization and a modest effect on the secondary structure of echinT. However, we observed a significant impact on the folding structure, as reflected by a significant lowering of the T{sub m} value. Kinetic analysis reveals that the C-terminal deletion mutants are within an order of magnitude less efficient in catalysis compared to wild type, while the overall kinetic mechanism that proceeds through a fast step, followed by a rate-limiting hydrolysis step, was conserved. Nevertheless, the ability of the C-terminal deletion mutants to hydrolyze lysyl-AMP generated by LysU was greatly impaired. Taken together, our results highlight the emerging role of the C-terminus in governing the catalytic function of Hints.

  11. Combined homo- and heterogeneous model for mercury speciation in pulverized fuel combustion flue gases

    SciTech Connect (OSTI)

    Shishir P. Sable; Wiebren de Jong; Hartmut Spliethoff [Delft University Technology, Delft (Netherlands). Section Energy Technology, Department of Process and Energy

    2008-01-15T23:59:59.000Z

    A new model is developed to predict Hg{sup 0}, Hg{sup +}, Hg{sup 2+}, and Hg{sub p} in the post-combustion zone upstream of a particulate control device (PCD) in pulverized coal-fired power plants. The model incorporates reactions of mercury with chlorinating agents (HCl) and other gaseous species and simultaneous adsorption of oxidized mercury (HgCl{sub 2}) on fly ash particles in the cooling of flue gases. The homogeneous kinetic model from the literature has been revised to understand the effect of the NO + OH + M {longleftrightarrow} HONO + M reaction on mercury oxidation. Because it is a pressure-dependent reaction, the choice of proper reaction rates was very critical. It was found that mercury oxidation reduces from 100 to 0% while going from high- to low-pressure limit rates with 100 ppmv NO. The heterogeneous model describes selective in-duct Langmuir-Hinshelwood adsorption of mercury chloride on ash particles. The heterogeneous model has been built using Fortran and linked to Chemkin 4.0. The final predictions of elemental, oxidized, and particulate mercury were compared to mercury speciation from power plant data. Information collection request (ICR) data were used for this comparison. The model results follow very similar trends compared to those of the plant data; however, quantitative deviation was considerable. These deviations are due to the errors in the measurement of mercury upstream of PCD, lack of adsorption kinetic data, accurate homogeneous reaction mechanisms, and certain modeling assumptions. The model definitely follows a new approach for the prediction of mercury speciation, and further refinement will improve the model significantly. 43 refs., 1 figs., 6 tabs.

  12. Homogenized dynamic constitutive relation for Bloch-wave propagation in periodic composites: structure and symmetries

    E-Print Network [OSTI]

    Nemat-Nasser, Sia

    Homogenized dynamic constitutive relation for Bloch-wave propagation in periodic composites composites has been made only very recently. Here we discuss the explicit form of the effective dynamic properties of composites with tailored microstructure necessitates a systematic homogenization procedure

  13. Simulation of CO2 Sequestration at Rock Spring Uplift, Wyoming: Heterogeneity and Uncertainties in Storage Capacity, Injectivity and Leakage

    SciTech Connect (OSTI)

    Deng, Hailin [Los Alamos National Laboratory; Dai, Zhenxue [Los Alamos National Laboratory; Jiao, Zunsheng [Wyoming State Geological Survey; Stauffer, Philip H. [Los Alamos National Laboratory; Surdam, Ronald C. [Wyoming State Geological Survey

    2011-01-01T23:59:59.000Z

    Many geological, geochemical, geomechanical and hydrogeological factors control CO{sub 2} storage in subsurface. Among them heterogeneity in saline aquifer can seriously influence design of injection wells, CO{sub 2} injection rate, CO{sub 2} plume migration, storage capacity, and potential leakage and risk assessment. This study applies indicator geostatistics, transition probability and Markov chain model at the Rock Springs Uplift, Wyoming generating facies-based heterogeneous fields for porosity and permeability in target saline aquifer (Pennsylvanian Weber sandstone) and surrounding rocks (Phosphoria, Madison and cap-rock Chugwater). A multiphase flow simulator FEHM is then used to model injection of CO{sub 2} into the target saline aquifer involving field-scale heterogeneity. The results reveal that (1) CO{sub 2} injection rates in different injection wells significantly change with local permeability distributions; (2) brine production rates in different pumping wells are also significantly impacted by the spatial heterogeneity in permeability; (3) liquid pressure evolution during and after CO{sub 2} injection in saline aquifer varies greatly for different realizations of random permeability fields, and this has potential important effects on hydraulic fracturing of the reservoir rock, reactivation of pre-existing faults and the integrity of the cap-rock; (4) CO{sub 2} storage capacity estimate for Rock Springs Uplift is 6614 {+-} 256 Mt at 95% confidence interval, which is about 36% of previous estimate based on homogeneous and isotropic storage formation; (5) density profiles show that the density of injected CO{sub 2} below 3 km is close to that of the ambient brine with given geothermal gradient and brine concentration, which indicates CO{sub 2} plume can sink to the deep before reaching thermal equilibrium with brine. Finally, we present uncertainty analysis of CO{sub 2} leakage into overlying formations due to heterogeneity in both the target saline aquifer and surrounding formations. This uncertainty in leakage will be used to feed into risk assessment modeling.

  14. Weak law of large numbers for some Markov chains along non homogeneous genealogies

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Weak law of large numbers for some Markov chains along non homogeneous genealogies Vincent Bansaye goes to infinity. It is described by a discrete genealogy which may be time non-homogeneous and we pay of the trait of each individual along this genealogy and may also be time non- homogeneous. Such models

  15. Self-sustained oscillations in homogeneous shear flow

    E-Print Network [OSTI]

    Victor Yakhot

    2002-06-27T23:59:59.000Z

    Generation of the large-scale coherent vortical structurs in homogeneous shear flow couples dynamical processes of energy and enstrophy production. In the large rate of strain limit, the simple estimates of the contributions to the energy and enstrophy equations result in a dynamical system, describing experimentally and numerically observed self-sustained non-linear oscillations of energy and enstrophy. It is shown that the period of these oscilaltions is independent upon the box size and the energy and enstrophy fluctuations are strongly correlated.

  16. Exhaust gas recirculation in a homogeneous charge compression ignition engine

    DOE Patents [OSTI]

    Duffy, Kevin P. (Metamora, IL); Kieser, Andrew J. (Morton, IL); Rodman, Anthony (Chillicothe, IL); Liechty, Michael P. (Chillicothe, IL); Hergart, Carl-Anders (Peoria, IL); Hardy, William L. (Peoria, IL)

    2008-05-27T23:59:59.000Z

    A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

  17. Controlling And Operating Homogeneous Charge Compression Ignition (Hcci) Engines

    DOE Patents [OSTI]

    Flowers, Daniel L. (San Leandro, CA)

    2005-08-02T23:59:59.000Z

    A Homogeneous Charge Compression Ignition (HCCI) engine system includes an engine that produces exhaust gas. A vaporization means vaporizes fuel for the engine an air induction means provides air for the engine. An exhaust gas recirculation means recirculates the exhaust gas. A blending means blends the vaporized fuel, the exhaust gas, and the air. An induction means inducts the blended vaporized fuel, exhaust gas, and air into the engine. A control means controls the blending of the vaporized fuel, the exhaust gas, and the air and for controls the inducting the blended vaporized fuel, exhaust gas, and air into the engine.

  18. Synergistic Catalysis between Pd and Fe in Gas Phase Hydrodeoxygenation of m-Cresol

    SciTech Connect (OSTI)

    Hong, Yongchun; Zhang, He; Sun, Junming; Karim, Ayman M.; Hensley, Alyssa; Gu, Meng; Engelhard, Mark H.; McEwen, Jean-Sabin; Wang, Yong

    2014-10-31T23:59:59.000Z

    In this work, a series of Pd/Fe2O3 catalysts were synthesized, characterized, and evaluated for the hydrodeoxygenation (HDO) of m-cresol. It was found that the addition of Pd remarkably promotes the catalytic activity of Fe while the product distributions resemble that of monometallic Fe catalyst, showing high selectivity towards the production of toluene (C-O cleavage without saturation of aromatic ring and C-C cleavage). Reduced catalysts featured with Pd patches on the top of reduced Fe nanoparticle surface, and the interaction between Pd and Fe was further confirmed using X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM) and X-ray absorption near edge fine structure (XANES). A possible mechanism, including Pd assisted H2 dissociation and Pd facilitated stabilization of metallic Fe surface as well as Pd enhanced product desorption, is proposed to be responsible for the high activity and HDO selectivity in Pd-Fe catalysts. The synergic catalysis derived from Pd-Fe interaction found in this work was proved to be applicable to other precious metal promoted Fe catalysts, providing a promising strategy for future design of highly active and selective HDO catalysts.

  19. Steam catalysis in CaO carbonation under low steam partial pressure

    SciTech Connect (OSTI)

    Yang, S.J.; Xiao, Y.H. [Chinese Academy of Science, Beijing (China)

    2008-06-15T23:59:59.000Z

    CaO was widely used to capture CO{sub 2} in direct hydrogen production process, where steam always existed simultaneously. The effect of steam on CaO carbonation performance under low steam partial pressure was investigated using a pressurized thermogravimetric apparatus. The experimental results revealed that steam improved CaO carbonation performance significantly no matter whether Ca(OH){sub 2} was produced or not. At 823 K and 0.5 MPa of steam partial pressure, effect of steam on CaO carbonation performance could not be attributed mainly to production of Ca(OH){sub 2} because the hydration rate of CaO was very slow. The main reason was steam catalysis in CaO carbonation. Enhancement of steam on CaO carbonation performance without Ca(OH){sub 2} production could not be attributed to improvement of steam on the physical property, but to catalytic effect of steam. Effects of CaO precursors, CO{sub 2} partial pressure, steam partial pressure, and temperature with steam addition on CaO carbonation performance were also investigated.

  20. Molecular Insights into Substrate Recognition and Catalysis by Tryptophan 2,3-dioxygenase

    SciTech Connect (OSTI)

    Forouhar,F.; Ross Anderson, J.; Mowat, C.; Vorobiev, S.; Hussain, A.; Abashidze, M.; Bruckmann, C.; Thackray, S.; Seetharaman, J.; et al.

    2007-01-01T23:59:59.000Z

    Tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) constitute an important, yet relatively poorly understood, family of heme-containing enzymes. Here, we report extensive structural and biochemical studies of the Xanthomonas campestris TDO and a related protein SO4414 from Shewanella oneidensis, including the structure at 1.6-{angstrom} resolution of the catalytically active, ferrous form of TDO in a binary complex with the substrate l-Trp. The carboxylate and ammonium moieties of tryptophan are recognized by electrostatic and hydrogen-bonding interactions with the enzyme and a propionate group of the heme, thus defining the l-stereospecificity. A second, possibly allosteric, l-Trp-binding site is present at the tetramer interface. The sixth coordination site of the heme-iron is vacant, providing a dioxygen-binding site that would also involve interactions with the ammonium moiety of l-Trp and the amide nitrogen of a glycine residue. The indole ring is positioned correctly for oxygenation at the C2 and C3 atoms. The active site is fully formed only in the binary complex, and biochemical experiments confirm this induced-fit behavior of the enzyme. The active site is completely devoid of water during catalysis, which is supported by our electrochemical studies showing significant stabilization of the enzyme upon substrate binding.

  1. INITIAL ANALYSIS OF TRANSIENT POWER TIME LAG DUE TO HETEROGENEITY WITHIN THE TREAT FUEL MATRIX.

    SciTech Connect (OSTI)

    D.M. Wachs; A.X. Zabriskie, W.R. Marcum

    2014-06-01T23:59:59.000Z

    The topic Nuclear Safety encompasses a broad spectrum of focal areas within the nuclear industry; one specific aspect centers on the performance and integrity of nuclear fuel during a reactivity insertion accident (RIA). This specific accident has proven to be fundamentally difficult to theoretically characterize due to the numerous empirically driven characteristics that quantify the fuel and reactor performance. The Transient Reactor Test (TREAT) facility was designed and operated to better understand fuel behavior under extreme (i.e. accident) conditions; it was shutdown in 1994. Recently, efforts have been underway to commission the TREAT facility to continue testing of advanced accident tolerant fuels (i.e. recently developed fuel concepts). To aid in the restart effort, new simulation tools are being used to investigate the behavior of nuclear fuels during facility’s transient events. This study focuses specifically on the characterizing modeled effects of fuel particles within the fuel matrix of the TREAT. The objective of this study was to (1) identify the impact of modeled heterogeneity within the fuel matrix during a transient event, and (2) demonstrate acceptable modeling processes for the purpose of TREAT safety analyses, specific to fuel matrix and particle size. Hypothetically, a fuel that is dominantly heterogeneous will demonstrate a clearly different temporal heating response to that of a modeled homogeneous fuel. This time difference is a result of the uniqueness of the thermal diffusivity within the fuel particle and fuel matrix. Using MOOSE/BISON to simulate the temperature time-lag effect of fuel particle diameter during a transient event, a comparison of the average graphite moderator temperature surrounding a spherical particle of fuel was made for both types of fuel simulations. This comparison showed that at a given time and with a specific fuel particle diameter, the fuel particle (heterogeneous) simulation and the homogeneous simulation were related by a multiplier relative to the average moderator temperature. As time increases the multiplier is comparable to the factor found in a previous analytical study from literature. The implementation of this multiplier and the method of analysis may be employed to remove assumptions and increase fidelity for future research on the effect of fuel particles during transient events.

  2. Argonne integrated heterogeneous file transfer network

    SciTech Connect (OSTI)

    Schofield, J.

    1984-01-01T23:59:59.000Z

    This presentation describes the computing environment at Argonne National Laboratory and the actions underway to implement a coherent hierarchy of computing systems connected through a heterogeneous file transfer network. A major goal of the Computing Services Division is to integrate heterogeneous computing elements incrementally into a nework, with the goal of having everything somehow connected to everything else. Using standard IBM networking protocols, we have already built a full-function computer-to-computer file transfer network of IBM and DEC VAX systems. Currently, the users on the IBM MVS and VM/CMS systems can use standard IBM commands to send files and mail to DEC VAX users and output devices, and they can receive files from the DEC VAX's as if they had been sent from other IBM systems; similarly, the DEC VAX users can use standard DEC commands to send files and mail to IBM users and output devices, and they can receive files from the IBM systems as if they had been sent from other DEC VAX systems. In fact, the VAXes can exchange files and mail among themselves via the IBM NJE-based network without the need for DECnet links between the VAXes. Because this integrated heterogeneous file transfer network uses the standard IBM peer-to-peer communications protocol, all of the Laboratory's IBM and DEC computers easily communicate with the approximately 170 other computers in the Bitnet university network. Plans call for further integration of existing HP 3000 systems and future word processing systems such as Exxon, NBI, or Wang; we believe it is vitally important to provide smooth paths into this network for users of personal desktop computers. 17 references.

  3. Heterogeneously integrated microsystem-on-a-chip

    DOE Patents [OSTI]

    Chanchani, Rajen (Albuquerque, NM)

    2008-02-26T23:59:59.000Z

    A microsystem-on-a-chip comprises a bottom wafer of normal thickness and a series of thinned wafers can be stacked on the bottom wafer, glued and electrically interconnected. The interconnection layer comprises a compliant dielectric material, an interconnect structure, and can include embedded passives. The stacked wafer technology provides a heterogeneously integrated, ultra-miniaturized, higher performing, robust and cost-effective microsystem package. The highly integrated microsystem package, comprising electronics, sensors, optics, and MEMS, can be miniaturized both in volume and footprint to the size of a bottle-cap or less.

  4. aquifer heterogeneity completion: Topics by E-print Network

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

    Sciences Websites Summary: Sequential Consistency for Heterogeneous-Race-Free DEREK R. HOWER, BRADFORD M. BECKMANN, BENEDICT R: Sequential Consistency for Data-Race-Free (SC for...

  5. aquifer heterogeneity final: Topics by E-print Network

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

    Sciences Websites Summary: Sequential Consistency for Heterogeneous-Race-Free DEREK R. HOWER, BRADFORD M. BECKMANN, BENEDICT R: Sequential Consistency for Data-Race-Free (SC for...

  6. axially heterogeneous core: Topics by E-print Network

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

    Sciences Websites Summary: Sequential Consistency for Heterogeneous-Race-Free DEREK R. HOWER, BRADFORD M. BECKMANN, BENEDICT R: Sequential Consistency for Data-Race-Free (SC for...

  7. aquifer property heterogeneity: Topics by E-print Network

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

    Sciences Websites Summary: Sequential Consistency for Heterogeneous-Race-Free DEREK R. HOWER, BRADFORD M. BECKMANN, BENEDICT R: Sequential Consistency for Data-Race-Free (SC for...

  8. analyzing heterogeneous samples: Topics by E-print Network

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

    Sciences Websites Summary: Sequential Consistency for Heterogeneous-Race-Free DEREK R. HOWER, BRADFORD M. BECKMANN, BENEDICT R: Sequential Consistency for Data-Race-Free (SC for...

  9. advanced heterogeneous catalysts: Topics by E-print Network

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

    Sciences Websites Summary: Sequential Consistency for Heterogeneous-Race-Free DEREK R. HOWER, BRADFORD M. BECKMANN, BENEDICT R: Sequential Consistency for Data-Race-Free (SC for...

  10. Heterogeneous Nucleation of Ice on Anthropogenic Organic Particles...

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

    Nucleation of Ice on Anthropogenic Organic Particles Collected in Mexico City. Heterogeneous Nucleation of Ice on Anthropogenic Organic Particles Collected in Mexico City....

  11. Heterogeneous ice nucleation and water uptake by field-collected...

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

    ice nucleation and water uptake by field-collected atmospheric particles below 273 K. Heterogeneous ice nucleation and water uptake by field-collected atmospheric particles below...

  12. Heterogeneous Structure Around the Jemez Volcanic Field, New...

    Open Energy Info (EERE)

    Heterogeneous Structure Around the Jemez Volcanic Field, New Mexico, USA, as Inferred from the Envelope Inversion of Active-Experiment Seismic Data Jump to: navigation, search...

  13. Competing contact processes on homogeneous networks with tunable clusterization

    E-Print Network [OSTI]

    Rybak, Marcin

    2012-01-01T23:59:59.000Z

    We investigate two homogeneous networks: the Watts-Strogatz network and the random Erdos-Renyi network, the latter with tunable clustering coefficient $C$. The network is an area of two competing contact processes, where nodes can be in two states, S or D. A node S becomes D with probability 1 if at least two its mutually linked neighbours are D. A node D becomes S with a given probability $p$ if at least one of its neighbours is S. The competition between the processes is described by a phase diagram, where the critical probability $p_c$ depends on the clustering coefficient $C$. For $p>p_c$ the rate of state S increases in time, seemingly to dominate in the whole system. Below $p_c$, the contribution of D-nodes remains finite. The numerical results, supported by mean field approach, indicate that the transition is discontinuous.

  14. Applications of Fourier analysis in homogenization and boundary layer

    E-Print Network [OSTI]

    Aleksanyan, Hayk; Sjölin, Per

    2012-01-01T23:59:59.000Z

    In this paper we prove convergence results for the boundary layer homogenization problem for solutions of partial differential system with rapidly oscillating Dirichlet data. Our method is based on analysis of oscillatory integrals. In the uniformly convex regime and smooth boundaries we prove pointwise as well as $L^p$ convergence results. Namely, we prove $|u_{\\e}(x)-u_0 (x)| \\leq C_{\\kappa} \\e^{(d-1)/2}\\frac{1}{d(x)^{\\kappa}}$, $\\forall x\\in D$, $ \\forall \\ \\kappa>d-1$, and for $1\\leq pboundary of $D$. In particular for $p=2$ our result relates to the recent result of D. G\\'{e}rarad-Varet and N. Masmoudi \\cite{GM}.

  15. The manufacture and performance of homogeneous microstructure SBR MOX fuel

    SciTech Connect (OSTI)

    Barker, Matthew A. [Nexia Solutions Ltd., British Technology Centre, Sellafield, CA20 1PG (United Kingdom); Stephenson, Keith; Weston, Rebecca [Sellafield Ltd., B582, Sellafield, CA20 1PG (United Kingdom)

    2007-07-01T23:59:59.000Z

    In the early 1980's, British experience in the manufacture of mixed-oxide fast reactor fuel was used to develop a new thermal MOX manufacturing route called the Short Binder-less Route (SBR). Laboratory- scale development led to the manufacture of commercial PWR fuel in a small pilot plant, and the construction of the full-scale dual-line Sellafield MOX Plant (SMP). SMP's first MOX assemblies are now under irradiation. SBR MOX is manufactured with 100% co-milled feedstock, leading to a microstructure dominated by a solid solution of (U,Pu)O{sub 2} at the nominal enrichment. A comprehensive fuel performance research programme has demonstrated the benign performance of SBR MOX up to 54 MWd/kgHM. In particular, the homogeneous microstructure is believed to be instrumental in the favourable fission gas retention and PCI resistance properties. (authors)

  16. Rotation Rate of Particle Pairs in Homogeneous Isotropic Turbulence

    E-Print Network [OSTI]

    Daddi-Moussa-Ider, Abdallah

    2015-01-01T23:59:59.000Z

    Understanding the dynamics of particles in turbulent flow is important in many environmental and industrial applications. In this paper, the statistics of particle pair orientation is numerically studied in homogeneous isotropic turbulent flow, with Taylor microscale Rynolds number of 300. It is shown that the Kolmogorov scaling fails to predict the observed probability density functions (PDFs) of the pair rotation rate and the higher order moments accurately. Therefore, a multifractal formalism is derived in order to include the intermittent behavior that is neglected in the Kolmogorov picture. The PDFs of finding the pairs at a given angular velocity for small relative separations, reveals extreme events with stretched tails and high kurtosis values. Additionally, The PDFs are found to be less intermittent and follow a complementary error function distribution for larger separations.

  17. Generalized quantum gravity condensates for homogeneous geometries and cosmology

    E-Print Network [OSTI]

    Daniele Oriti; Daniele Pranzetti; James P. Ryan; Lorenzo Sindoni

    2015-01-05T23:59:59.000Z

    We construct a generalized class of quantum gravity condensate states, that allows the description of continuum homogeneous quantum geometries within the full theory. They are based on similar ideas already applied to extract effective cosmological dynamics from the group field theory formalism, and thus also from loop quantum gravity. However, they represent an improvement over the simplest condensates used in the literature, in that they are defined by an infinite superposition of graph-based states encoding in a precise way the topology of the spatial manifold. The construction is based on the definition of refinement operators on spin network states, written in a second quantized language. The construction lends itself easily to be applied also to the case of spherically symmetric quantum geometries.

  18. Structural, Spectroscopic, And Theoretical Elucidation of a Redox-Active Pincer-Type Ancillary Applied in Catalysis

    SciTech Connect (OSTI)

    Adhikari, D.; Mossin, S.; Basuli, F.; Huffman, J.C.; Szilagyi, R.K.; Meyer, K.; Mindiola, D.J.

    2009-05-11T23:59:59.000Z

    Pincer-type ligands are believed to be very robust scaffolds that can support multifarious functionalities as well as highly reactive metal motifs applied in organometallic chemistry, especially in the realm of catalysis. In this paper, we describe the redox and, therefore, noninnocent behavior of a PNP (PNP{sup -} = N[2-P(CHMe{sub 2}){sub 2}-4-methylphenyl]{sub 2}) pincer ancillary bound to nickel. A combination of structural, spectroscopic, and theoretical techniques suggests that this type of framework can house an electron hole when coordinated to Ni(II).

  19. Intrinsic Nanoscience of ? Pu-Ga Alloys: Local Structure and Speciation, Collective Behavior, Nanoscale Heterogeneity, and Aging Mechanisms

    SciTech Connect (OSTI)

    Conradson, Steven D.; Bock, Nicolas; Castro, Julio M.; Conradson, Dylan R.; Cox, Lawrence E.; Dmowski, Wojtek; Dooley, David E.; Egami, Takeshi; Espinosa-Faller, Francisco J.; Freibert, Franz J.; Garcia-Adeva, Angel J.; Hess, Nancy J.; Holmstrom, Erik; Howell, Rafael C.; Katz, Barbara A.; Lashley, Jason C.; Martinez, Raymond J.; Moore, David P.; Morales, Luis A.; Olivas, J David; Pereyra, Ramiro A.; Ramos, Michael; Terry, Jeff H.; Villella, Phillip M.

    2014-04-24T23:59:59.000Z

    Because diffraction measurements are sensitive only to the long range average arrangement of the atoms in the coherent portion of a crystal, complementary local structure measurements are required for a complete understanding of the structure of a complex material. This is particularly an issue in solid solutions where even random distributions of a solute will result in nanometer-scale fluctuations in the local composition. The structure will be further complicated if collective and cooperative phenomena organize the solute distribution via longer range interactions between non-bonded solute sites. If the solute affects the phase stability then the question is raised of whether the atoms in domains with local compositions outside the limits of the bulk phase will rearrange into the structure stable for that composition and temperature or if the resulting stress would prevent such a local phase transition. If the former, then phase separated, heterogeneous structures at or below the diffraction limit will form. This nanometerscale competition between the phase transition and the epitaxial mismatch – exacerbated by the added strain if the transition involves a volume change – raises the potential for the formation of novel structures that do not occur in bulk material, e.g., fcc Fe. This coupling over multiple scales between inhomogeneity ordering, elastic forces, phase competition, and texture in the form of coexisting structures is a hallmark of martensites, a class of complex materials that includes ?-stabilized PuGa and that often exhibit correlated atomic and electronic properties. The enigmatic and extreme nature of Pu is consistent with its exhibiting unusual structural behavior of this type, including nanoscale heterogeneity in ?-stabilized PuGa and its enhanced homogeneity on aging that has been suggested based on earlier X-ray Absorption Fine Structure (XAFS) spectroscopy and x-ray pair distribution function (pdf) measurements. Measurements on a defined set of laboratory-prepared materials now corroborate and better describe this heterogeneity while additional aged samples demonstrate the role of heterogeneity in aging processes in Pu.

  20. Energy Conservation in Heterogeneous Server Clusters Taliver Heath

    E-Print Network [OSTI]

    Bianchini, Ricardo

    Energy Conservation in Heterogeneous Server Clusters #3; Taliver Heath Dept. of Computer Science, measurement Keywords Energy conservation, server clusters, heterogeneity #3; This research has been supported.g., [3, 4, 9, 21]) and dynamic cluster recon#12;guration for energy conservation without per- formance

  1. The dynamics of chimera states in heterogeneous Kuramoto networks

    E-Print Network [OSTI]

    Laing, Carlo R.

    The dynamics of chimera states in heterogeneous Kuramoto networks Carlo R. Laing a a. Abstract We study a variety of mixed synchronous/incoherent ("chimera") states in sev- eral heterogeneous with one another, while the remainder are incoherent [7­15], referred to by Abrams et al. as "chimera

  2. On the Throughput Capacity of Heterogeneous Wireless Networks

    E-Print Network [OSTI]

    Latchman, Haniph A.

    On the Throughput Capacity of Heterogeneous Wireless Networks Pan Li, Member, IEEE, and Yuguang of wireless networks. However, it is commonly assumed that all nodes in the network are identical. The issue of heterogeneous wireless networks with general network settings. Specifically, we consider an extended network

  3. The Specification and Execution of Heterogeneous Synchronous Reactive Systems

    E-Print Network [OSTI]

    The Specification and Execution of Heterogeneous Synchronous Reactive Systems by Stephen Anthony in Engineering---Electrical Engineering and Computer Sciences in the GRADUATE DIVISION of the UNIVERSITY of Heterogeneous Synchronous Reactive Systems Copyright ã 1997 by Stephen Anthony Edwards #12; Abstract

  4. An Availability-Aware Task Scheduling Strategy for Heterogeneous Systems

    E-Print Network [OSTI]

    Xie, Tao

    An Availability-Aware Task Scheduling Strategy for Heterogeneous Systems Xiao Qin, Member, IEEE, and Tao Xie, Member, IEEE Abstract--High availability is a key requirement in the design and development of heterogeneous systems where processors operate at different speeds and are not continuously available

  5. Dynamic Resource Management in Energy Constrained Heterogeneous Computing

    E-Print Network [OSTI]

    Maciejewski, Anthony A.

    Dynamic Resource Management in Energy Constrained Heterogeneous Computing Systems Using Voltage) in a manner that exploits the heterogeneity of the resources and tasks while considering the energy the resources are wireless and mobile, the limited battery capacity becomes a constraint and power or energy

  6. OSCAR Parallelizing Compiler Cooperative Heterogeneous Multi-core Architecture

    E-Print Network [OSTI]

    Kasahara, Hironori

    OSCAR Parallelizing Compiler Cooperative Heterogeneous Multi-core Architecture Akihiro Hayashi,kamiyama,watanabe,takeshi,mase}@kasahara.cs.waseda.ac.jp 1. Background Heterogeneous multi-core architectures, which integrates multiple general purpose CPU, powerful parallelizing compiler for hetero- geneous multi-core architectures is expected. Furthermore

  7. On the Numerical Simulation of Waterflooding of Heterogeneous

    E-Print Network [OSTI]

    Furtado, Fred

    On the Numerical Simulation of Waterflooding of Heterogeneous Petroleum Reservoirs Jim Douglas, Jr Simulation of Waterflooding of Heterogeneous Petroleum Reservoirs · A two-stage operator-splitting allows consider as a model problem the two-phase immiscible displacement in petroleum reservoirs. A very detailed

  8. On the Numerical Simulation of Waterflooding of Heterogeneous

    E-Print Network [OSTI]

    Douglas Jr., Jim

    On the Numerical Simulation of Waterflooding of Heterogeneous Petroleum Reservoirs Jim Douglas, Jr displacement in petroleum reservoirs. A very detailed description of the numerical method is presented. Follow, 22290 Rio de Janeiro, RJ, Brazil #12; On the Numerical Simulation of Waterflooding of Heterogeneous

  9. Mining Competitive Relationships by Learning across Heterogeneous Networks

    E-Print Network [OSTI]

    Menczer, Filippo

    . Existing studies mainly focus on mining competitive relationships within a single data source, whileMining Competitive Relationships by Learning across Heterogeneous Networks Yang Yang , Jie Tang. In this paper, we study the problem of mining competitive rela- tionships by learning across heterogeneous

  10. Optimizing the Cost of an Heterogeneous Distributed Platform

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Optimizing the Cost of an Heterogeneous Distributed Platform Jean-Marc Nicod, Laurent Philippe [nicod,philippe,sabbah]@lifc.univ-fcomte.fr Abstract--Distributed platforms become heterogeneous in more. For production grids and factories, it is mandatory to control and optimize the economic cost of a such platforms

  11. Dynamic Lung Morphology of Methacholine-Induced Heterogeneous Bronchoconstriction

    E-Print Network [OSTI]

    Dynamic Lung Morphology of Methacholine-Induced Heterogeneous Bronchoconstriction Ben T. Chen and G). The method provides direct visualization of the venti- lated regions within the lung. Heterogeneous bronchoconstric- tion following the i.v. MCh injection was evident using this technique. These 3 He dynamic lung

  12. DESCRIPTION OF HETEROGENEOUS USING PRESSURE AND TRACER DATA

    E-Print Network [OSTI]

    Stanford University

    DESCRIPTION OF HETEROGENEOUS RESERVOIRS USING PRESSURE AND TRACER DATA A DISSERTATION SUBMITTED of characterizing areally heterogeneous reservoirs through the interpretation of pressure data and tracer data for the selected reservoir model, increases the tolerance to noise in the data, increases the confidence

  13. Hydrovinylation of Norbornene. Ligand-Dependent Selectivity and

    E-Print Network [OSTI]

    RajanBabu, T. V. "Babu"

    . W.; Wilke, G. Hydrovinylation. In Applied Homogeneous Catalysis with Organometallic Compounds, J.; Kuhn, H. Preparation of Optically ActiVe Azaphospholenes and Their Use in Catalysis

  14. Dynamics on modular networks with heterogeneous correlations

    SciTech Connect (OSTI)

    Melnik, Sergey [MACSI, Department of Mathematics and Statistics, University of Limerick (Ireland) [MACSI, Department of Mathematics and Statistics, University of Limerick (Ireland); Oxford Centre for Industrial and Applied Mathematics, Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom); CABDyN Complexity Centre, University of Oxford, Oxford OX1 1HP (United Kingdom); Porter, Mason A. [Oxford Centre for Industrial and Applied Mathematics, Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom) [Oxford Centre for Industrial and Applied Mathematics, Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom); CABDyN Complexity Centre, University of Oxford, Oxford OX1 1HP (United Kingdom); Mucha, Peter J. [Department of Mathematics, Carolina Center for Interdisciplinary Applied Mathematics, University of North Carolina, Chapel Hill, North Carolina 27599-3250 (United States) [Department of Mathematics, Carolina Center for Interdisciplinary Applied Mathematics, University of North Carolina, Chapel Hill, North Carolina 27599-3250 (United States); Institute for Advanced Materials, Nanoscience and Technology, University of North Carolina, Chapel Hill, North Carolina 27599-3216 (United States); Gleeson, James P. [MACSI, Department of Mathematics and Statistics, University of Limerick (Ireland)] [MACSI, Department of Mathematics and Statistics, University of Limerick (Ireland)

    2014-06-15T23:59:59.000Z

    We develop a new ensemble of modular random graphs in which degree-degree correlations can be different in each module, and the inter-module connections are defined by the joint degree-degree distribution of nodes for each pair of modules. We present an analytical approach that allows one to analyze several types of binary dynamics operating on such networks, and we illustrate our approach using bond percolation, site percolation, and the Watts threshold model. The new network ensemble generalizes existing models (e.g., the well-known configuration model and Lancichinetti-Fortunato-Radicchi networks) by allowing a heterogeneous distribution of degree-degree correlations across modules, which is important for the consideration of nonidentical interacting networks.

  15. Numerical homogenization of concrete microstructures without explicit meshes

    SciTech Connect (OSTI)

    Sanahuja, Julien, E-mail: julien.sanahuja@edf.fr; Toulemonde, Charles, E-mail: charles.toulemonde@edf.fr

    2011-12-15T23:59:59.000Z

    Life management of electric hydro or nuclear power plants requires to estimate long-term concrete properties on facilities, for obvious safety and serviceability reasons. Decades-old structures are foreseen to be operational for several more decades. As a large number of different concrete formulations are found in EDF facilities, empirical models based on many experiments cannot be an option for a large fleet of power plant buildings. To build predictive models, homogenization techniques offer an appealing alternative. To properly upscale creep, especially at long term, a rather precise description of the microstructure is required. However, the complexity of the morphology of concrete poses several challenges. In particular, concrete is formulated to maximize the packing density of the granular skeleton, leading to aggregates spanning several length scales with small inter particle spacings. Thus, explicit meshing of realistic concrete microstructures is either out of reach of current meshing algorithms or would produce a number of degrees of freedom far higher than the current generic FEM codes capabilities. This paper proposes a method to deal with complex matrix-inclusions microstructures such as the ones encountered at the mortar or concrete scales, without explicitly meshing them. The microstructure is superimposed to an independent mesh, which is a regular Cartesian grid. This inevitably yields so called 'gray elements', spanning across multiple phases. As the reliability of the estimate of the effective properties highly depends on the behavior affected to these gray elements, special attention is paid to them. As far as the question of the solvers is concerned, generic FEM codes are found to lack efficiency: they cannot reach high enough levels of discretization with classical free meshes, and they do not take advantage of the regular structure of the mesh. Thus, a specific finite differences/finite volumes solver has been developed. At first, generic off-the-shelf linear system solvers were used. To further improve the efficiency in terms of memory requirements, specific variants of the preconditioned conjugate gradient were implemented. This allowed to homogenize the conductivity of a concrete-like microstructure using more than 10{sup 9} degrees of freedom on a rather common hardware for 2010 (a PC embedding 48 GB of RAM). Taking benefit of the properties of the regular Cartesian grid we have also investigated a multi-level method to improve the CPU efficiency of the code.

  16. Accelerating Subsurface Transport Simulation on Heterogeneous Clusters

    SciTech Connect (OSTI)

    Villa, Oreste; Gawande, Nitin A.; Tumeo, Antonino

    2013-09-23T23:59:59.000Z

    Reactive transport numerical models simulate chemical and microbiological reactions that occur along a flowpath. These models have to compute reactions for a large number of locations. They solve the set of ordinary differential equations (ODEs) that describes the reaction for each location through the Newton-Raphson technique. This technique involves computing a Jacobian matrix and a residual vector for each set of equation, and then solving iteratively the linearized system by performing Gaussian Elimination and LU decomposition until convergence. STOMP, a well known subsurface flow simulation tool, employs matrices with sizes in the order of 100x100 elements and, for numerical accuracy, LU factorization with full pivoting instead of the faster partial pivoting. Modern high performance computing systems are heterogeneous machines whose nodes integrate both CPUs and GPUs, exposing unprecedented amounts of parallelism. To exploit all their computational power, applications must use both the types of processing elements. For the case of subsurface flow simulation, this mainly requires implementing efficient batched LU-based solvers and identifying efficient solutions for enabling load balancing among the different processors of the system. In this paper we discuss two approaches that allows scaling STOMP's performance on heterogeneous clusters. We initially identify the challenges in implementing batched LU-based solvers for small matrices on GPUs, and propose an implementation that fulfills STOMP's requirements. We compare this implementation to other existing solutions. Then, we combine the batched GPU solver with an OpenMP-based CPU solver, and present an adaptive load balancer that dynamically distributes the linear systems to solve between the two components inside a node. We show how these approaches, integrated into the full application, provide speed ups from 6 to 7 times on large problems, executed on up to 16 nodes of a cluster with two AMD Opteron 6272 and a Tesla M2090 per node.

  17. Method of fabricating a homogeneous wire of inter-metallic alloy

    DOE Patents [OSTI]

    Ohriner, Evan Keith (Knoxville, TN); Blue, Craig Alan (Knoxville, TN)

    2001-01-01T23:59:59.000Z

    A method for fabricating a homogeneous wire of inter-metallic alloy comprising the steps of providing a base-metal wire bundle comprising a metal, an alloy or a combination thereof; working the wire bundle through at least one die to obtain a desired dimension and to form a precursor wire; and, controllably heating the precursor wire such that a portion of the wire will become liquid while simultaneously maintaining its desired shape, whereby substantial homogenization of the wire occurs in the liquid state and additional homogenization occurs in the solid state resulting in a homogenous alloy product.

  18. Solar energy storage through the homogeneous electrocatalytic reduction of carbon dioxide : photoelectrochemical and photovoltaic approaches

    E-Print Network [OSTI]

    Sathrum, Aaron John

    2011-01-01T23:59:59.000Z

    electricity from photovoltaic cells to convert CO 2 intoSolar Energy Anode Photovoltaic Cell Cathode PP Mesh SpacerCoupling a Photovoltaic Solar Cell with a Homogeneous

  19. Improved Modeling of Transition Metals, Applications to Catalysis and Technetium Chemistry

    SciTech Connect (OSTI)

    Cundari, T. R.

    2004-03-05T23:59:59.000Z

    There is considerable impetus for identification of aqueous OM catalysts as water is the ultimate ''green'' solvent. In collaboration with researchers at Ames Lab, we investigated effective fragment and Monte Carlo techniques for aqueous-phase hydroformylation (HyF). The Rh of the HyF catalyst is weakly aquated, in contrast to the hydride of the Rh-H bond. As the insertion of the olefin C=C into Rh-H determines the linear-to-branched aldehyde ratio, it is reasonable to infer that solvent plays an important role in regiochemistry. Studies on aqueous-phase organometallic catalysis were complemented in studies of the gas-phase reaction. A Rh-carbonyl-phosphine catalyst was investigated. Two of the most important implications of this research include (a) pseudorotation among five-coordinate intermediates is significant in HyF, and (b) CO insertion is the rate-determining step. The latter is in contrast to experimental deductions, highlighting the need for more accurate modeling. To this end, we undertook studies of (a) experimentally relevant PR{sub 3} co-ligands (PMe{sub 3}, PPh{sub 3}, P(p-PhSO{sub 3{sup -}}){sub 3}, etc.), and (b) HyF of propene. For the propylene research, simulations indicated that the linear: branched aldehyde ratio (linear is more desirable) is determined by thermodynamic discrimination of two distinct pathways. Other projects include a theory-experiment study of C-H activation by early transition metal systems, which establishes that weakly-bound adducts play a key role in activity selectivity. By extension, more selective catalysts for functionalization of methane (major component of natural gas) will require better understanding of these adducts, which are greatly affected by steric interactions with the ligands. In the de novo design of Tc complexes, we constructed (and are now testing) a coupled quantum mechanics-molecular mechanics protocol. Initial research shows it to be capable of accurately predicting structure ''from scratch.'' Challenges include conformational, geometric, coordination, spin, and particularly linkage (e.g., Tc-SCN versus Tc-NCS) isomerism. In general, our protocol can rapidly (<1 day with desktop software/hardware) predict the structure of diverse Tc complexes with an accuracy commensurate to organics. Our de novo strategy is also being used to investigate tris-pyrazolyl borate (Tp) complexes. Data suggests a fundamental difference in methane activation between TpRe and related CpRe complexes. Furthermore, Tp is a more electronically ''flexible'' platform for catalysts modification than Cp.

  20. Resonant Interactions in Rotating Homogeneous Three-dimensional Turbulence

    E-Print Network [OSTI]

    Q. Chen; S. Chen; G. L. Eyink; D. D. Holm

    2004-04-29T23:59:59.000Z

    Direct numerical simulations of three-dimensional (3D) homogeneous turbulence under rapid rigid rotation are conducted to examine the predictions of resonant wave theory for both small Rossby number and large Reynolds number. The simulation results reveal that there is a clear inverse energy cascade to the large scales, as predicted by 2D Navier-Stokes equations for resonant interactions of slow modes. As the rotation rate increases, the vertically-averaged horizontal velocity field from 3D Navier-Stokes converges to the velocity field from 2D Navier-Stokes, as measured by the energy in their difference field. Likewise, the vertically-averaged vertical velocity from 3D Navier-Stokes converges to a solution of the 2D passive scalar equation. The energy flux directly into small wave numbers in the $k_z=0$ plane from non-resonant interactions decreases, while fast-mode energy concentrates closer to that plane. The simulations are consistent with an increasingly dominant role of resonant triads for more rapid rotation.

  1. Homogeneous isotropic turbulence in dilute polymers: scale by scale budget

    E-Print Network [OSTI]

    E. De Angelis; C. M. Casciola; R. Benzi; R. Piva

    2002-08-09T23:59:59.000Z

    The turbulent energy cascade in dilute polymers solution is addressed here by considering a direct numerical simulation of homogeneous isotropic turbulence of a FENE-P fluid in a triply periodic box. On the basis of the DNS data, a scale by scale analysis is provided by using the proper extension to visco-elastic fluids of the Karman-Howarth equation for the velocity. For the microstructure, an equation, analogous to the Yaglom equation for scalars, is proposed for the free-energy density associated to the elastic behavior of the material. Two mechanisms of energy removal from the scale of the forcing are identified, namely the classical non-linear transfer term of the standard Navier-Stokes equations and the coupling between macroscopic velocity and microstructure. The latter, on average, drains kinetic energy to feed the dynamics of the microstructure. The cross-over scale between the two corresponding energy fluxes is identified, with the flux associated with the microstructure dominating at small separations to become sub-leading above the cross-over scale, which is the equivalent of the elastic limit scale defined by De Gennes-Tabor on the basis of phenomenological assumptions.

  2. Homogeneous ice nucleation evaluated for several water models

    E-Print Network [OSTI]

    J. R. Espinosa; E. Sanz; C. Valeriani; C. Vega

    2014-11-25T23:59:59.000Z

    In this work, we evaluate by means of computer simulations the rate for ice homogeneous nucleation for several water models such as TIP4P, TIP4P/2005,TIP4P/ICE, and mW (following the same procedure as in Sanz et al. [J. Am. Chem. Soc.135, 15008 (2013)]) in a broad temperature range. We estimate the ice-liquid interfacial free-energy, and conclude that for all water models {\\gamma} decreases as the temperature decreases. Extrapolating our results to the melting temperature, we obtain a value of the interfacial free-energy between 25 and 32 mN/m in reasonable agreement with the reported experimental values. Moreover, we observe that the values of {\\gamma} depend on the chosen water model and this is a key factor when numerically evaluating nucleation rates, given that the kinetic prefactor is quite similar for all water models with the exception of the mW (due to the absence of hydrogens). Somewhat surprisingly the estimates of the nucleation rates found in this work for TIP4P/2005 are slightly higher than those of the mW model, even though the former has explicit hydrogens. Our results suggest that it may be possible to observe in computer simulations spontaneous crystallization of TIP4P/2005 at about 60 K below the melting point.

  3. Dynamic control of a homogeneous charge compression ignition engine

    DOE Patents [OSTI]

    Duffy, Kevin P. (Metamora, IL); Mehresh, Parag (Peoria, IL); Schuh, David (Peoria, IL); Kieser, Andrew J. (Morton, IL); Hergart, Carl-Anders (Peoria, IL); Hardy, William L. (Peoria, IL); Rodman, Anthony (Chillicothe, IL); Liechty, Michael P. (Chillicothe, IL)

    2008-06-03T23:59:59.000Z

    A homogenous charge compression ignition engine is operated by compressing a charge mixture of air, exhaust and fuel in a combustion chamber to an autoignition condition of the fuel. The engine may facilitate a transition from a first combination of speed and load to a second combination of speed and load by changing the charge mixture and compression ratio. This may be accomplished in a consecutive engine cycle by adjusting both a fuel injector control signal and a variable valve control signal away from a nominal variable valve control signal. Thereafter in one or more subsequent engine cycles, more sluggish adjustments are made to at least one of a geometric compression ratio control signal and an exhaust gas recirculation control signal to allow the variable valve control signal to be readjusted back toward its nominal variable valve control signal setting. By readjusting the variable valve control signal back toward its nominal setting, the engine will be ready for another transition to a new combination of engine speed and load.

  4. Soliton ratchets in homogeneous nonlinear Klein-Gordon systems

    E-Print Network [OSTI]

    Luis Morales-Molina; Niurka R. Quintero; Franz G. Mertens; Angel Sanchez

    2005-11-30T23:59:59.000Z

    We study in detail the ratchet-like dynamics of topological solitons in homogeneous nonlinear Klein-Gordon systems driven by a bi-harmonic force. By using a collective coordinate approach with two degrees of freedom, namely the center of the soliton, $X(t)$, and its width, $l(t)$, we show, first, that energy is inhomogeneously pumped into the system, generating as result a directed motion; and, second, that the breaking of the time shift symmetry gives rise to a resonance mechanism that takes place whenever the width $l(t)$ oscillates with at least one frequency of the external ac force. In addition, we show that for the appearance of soliton ratchets, it is also necesary to break the time-reversal symmetry. We analyze in detail the effects of dissipation in the system, calculating the average velocity of the soliton as a function of the ac force and the damping. We find current reversal phenomena depending on the parameter choice and discuss the important role played by the phases of the ac force. Our analytical calculations are confirmed by numerical simulations of the full partial differential equations of the sine-Gordon and $\\phi^4$ systems, which are seen to exhibit the same qualitative behavior. Our results are in agreement with recent experimental work on dissipation induced symmetry breaking.

  5. Type Ia Supernova Explosion Models: Homogeneity versus Diversity

    E-Print Network [OSTI]

    W. Hillebrandt; J. C. Niemeyer; M. Reinecke

    2000-05-30T23:59:59.000Z

    Type Ia supernovae (SN Ia) are generally believed to be the result of the thermonuclear disruption of Chandrasekhar-mass carbon-oxygen white dwarfs, mainly because such thermonuclear explosions can account for the right amount of Ni-56, which is needed to explain the light curves and the late-time spectra, and the abundances of intermediate-mass nuclei which dominate the spectra near maximum light. Because of their enormous brightness and apparent homogeneity SN Ia have become an important tool to measure cosmological parameters. In this article the present understanding of the physics of thermonuclear explosions is reviewed. In particular, we focus our attention on subsonic (``deflagration'') fronts, i.e. we investigate fronts propagating by heat diffusion and convection rather than by compression. Models based upon this mode of nuclear burning have been applied very successfully to the SN Ia problem, and are able to reproduce many of their observed features remarkably well. However, the models also indicate that SN Ia may differ considerably from each other, which is of importance if they are to be used as standard candles.

  6. Panaches horizontaux non-Boussinesq en milieu homog\\`ene

    E-Print Network [OSTI]

    Daddi-Moussa-Ider, Abdallah; Mehaddi, Rabah; Vauquelin, Olivier; Candelier, Fabien

    2014-01-01T23:59:59.000Z

    The environmental impact of pollutants and effluents discharged into the atmosphere or the oceans has led researchers to conduct studies related to this issue. Several works have been carried out in this context in order to reduce the effect on the local environment. These types of ejections in nature are modeled as jets in the presence of a density gradient. In this study we treated the problem of inclined round turbulent buoyant jets and plumes ejected in a homogeneous or stratified fluid, at rest or in motion. The prediction of the flow behavior, i.e. the evolution of its variables, is first treated theoretically from a model whose formalism is valid in both the Boussinesq case as well as in the non-Boussinesq general case. Solving the equations governing the plumes is performed numerically using a Runge-Kutta 4th order. To validate the model, laboratory experiments are performed with round jets of air and helium for a wide range of densities. The confrontation theory-experience aims here to fix the limits...

  7. Molecular Active Sites in Heterogeneous Ir-La/C Catalyzed Carbonylatio...

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

    Molecular Active Sites in Heterogeneous Ir-LaC Catalyzed Carbonylation of Methanol to Acetates. Molecular Active Sites in Heterogeneous Ir-LaC Catalyzed Carbonylation of Methanol...

  8. Towards a multifrontal QR factorization for heterogeneous architectures over runtime systems

    E-Print Network [OSTI]

    Uçar, Bora

    , computer architectures for high performance computing have considerably evolved toward heterogeneous. An example of popular heterogeneous architectures widely adopted in the high performance computing domain

  9. Homogeneous middles vs. heterogeneous tails, and the end of the ‘Inverted-U’: the share of the rich is what it's all about

    E-Print Network [OSTI]

    Palma, José Gabriel

    2011-01-26T23:59:59.000Z

    relatively minor (but much heralded) improvement at the other end.13 As a result, although the median remained static (40.6 and 41, respectively), the harmonic mean increased significantly (from 35.7 to 40).14 And as there was a decline in the standard... statistic at least as extreme as the one that was actually observed, assuming that the null hypothesis is true) of 36.3 per cent and 14.7 per cent, respectively. And if the regression is run with only one of the two slopes at a time, although the slope...

  10. Degradation of resolution in a homogeneous dual readout hadronic calorimeter

    E-Print Network [OSTI]

    Donald E. Groom

    2012-12-26T23:59:59.000Z

    If the response to a hadronic shower in a semi-infinite uniform calorimeter structure is $S$ relative to the electronic response, then $S/E = [\\fem + (1-\\fem)(h/e)]$, where $E$ is the incident hadron energy, $\\fem$ is the electronic shower fraction, and $h/e$ is the hadron/electron response ratio. In conventional calorimeters the energy resolution is dominated by the stochastic variable $\\fem$, whose broad, skewed pdf has an energy-dependent mean. The slow increase of the mean with $E$ is responsible for response nonlinearity and the skewness results in a non-Gaussian response. If the cascade is observed in two channels with different values of $h/e$ (typically scintillator($S$) and Cherenkov ($C$)), $\\fem$ can be eliminated. An energy estimator, linear in $C$ and $S$, is obtained which is proportional to the incident hadron's energy. The resolution depends upon the contrast in $h/e$ between the two channels. The Cherenkov $h/e$ will be 0.20--0.25. In sampling calorimeters, $h/e$ can be increased to about 0.7 by arranging for preferential absorption of the electromagnetic (EM) shower energy in the absorber (decreasing $e$) and using a hydrogenous detector (organic scintillator) to enhance $h$ through the contribution of recoil protons in $n$--$p$ scattering. Neither mechanism is available in a homogeneous crystal or glass scintillator,\\rm where $h/e$is expected to be in the vicinity of 0.4 because of invisible hadronic energy loss and other effects. The $h/e$ contrast is very likely too small to provide the needed energy resolution. We support this conclusion with simple Monte Carlo simulations.

  11. SELECTIVE REDUCTION OF NOX IN OXYGEN RICH ENVIRONMENTS WITH PLASMA-ASSISTED CATALYSIS: CATALYST DEVELOPMENT AND MECHANISTIC STUDIES

    SciTech Connect (OSTI)

    Peden, C; Barlow, S; Hoard, J; Kwak, J; *Balmer-Millar, M; *Panov, A; Schmieg, S; Szanyi, J; Tonkyn, R

    2003-08-24T23:59:59.000Z

    The control of NOx (NO and NO2) emissions from so-called ''lean-burn'' vehicle engines remains a challenge. In recent years, there have been a number of reports that show that a plasma device combined with a catalyst can reduce as high as 90% or more of NOx in simulated diesel and other ''lean-burn'' exhaust. In the case of propylene containing simulated diesel exhaust, the beneficial role of a plasma treatment is now thought to be due to oxidation of NO to NO2, and the formation of partially oxidized hydrocarbons that are more active for the catalytic reduction of NO2 than propylene. Thus, the overall system can be most usefully described as hydrocarbon selective catalytic reduction (SCR) enhanced by 'reforming' the exhaust with a non-thermal plasma (NTP) device. For plasma-enhanced catalysis, both zeolite- and alumina-based materials have shown high activity, albeit in somewhat different temperature ranges, when preceded by an NTP reactor. This paper will briefly describe our research efforts aimed at optimizing the catalyst materials for NTP-catalysis devices based, in part, on our continuing studies of the NTP- and catalytic-reaction mechanisms. Various alkali- and alkaline earth-cation-exchanged Y zeolites have been prepared, their material properties characterized, and they have been tested as catalytic materials for NOx reduction in laboratory NTP-catalysis reactors. Interestingly, NO2 formed in the plasma and not subsequently removed over these catalysts, will back-convert to NO, albeit to varying extents depending upon the nature of the cation. Besides this comparative reactivity, we will also discuss selected synthesis strategies for enhancing the performance of these zeolite-based catalyst materials. A particularly important result from our mechanistic studies is the observation that aldehydes, formed during the plasma treatment of simulated diesel exhaust, are the important species for the reduction of NOx to N2. Indeed, acetaldehyde has been found to be especially effective in the thermal reduction of both NO and NO2 over Ba- and Na-Y zeolite catalysts.

  12. Analysis of combustion in a small homogeneous charge compression assisted ignition engine

    E-Print Network [OSTI]

    237 Analysis of combustion in a small homogeneous charge compression assisted ignition engine H Ma1 characteristics to homogeneous charge compression ignition (HCCI) engines. Difficulties such as unknown ignition timing and the polytropic index have been addressed by combining both heat release and mass fraction burn

  13. Equivalence of Control Systems with Linear Systems on Lie Groups and Homogeneous Spaces

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Equivalence of Control Systems with Linear Systems on Lie Groups and Homogeneous Spaces Philippe of geometric control theory arguments. Keywords: Lie groups; Homogeneous spaces; Linear systems; Com- plete JOUAN 28th November 2008 Abstract The aim of this paper is to prove that a control affine system

  14. Effect of high pressure homogenization on the physical properties of milk

    E-Print Network [OSTI]

    Gonzalez De Cossio, Carlos

    1994-01-01T23:59:59.000Z

    Milk was homogenized at pressures ranging from 17.2 MPa to 100 MPa to determine the effect of homogenization pressure on the fat globule size distribution, viscosity, color, and temperature changes in milk. Milk containing 0, 1.5 and 3.0% milk fat...

  15. Application of the Hanbury BrownTwiss effect to scattering from quasi-homogeneous media

    E-Print Network [OSTI]

    Visser, Taco D.

    Application of the Hanbury Brown­Twiss effect to scattering from quasi-homogeneous media David: Hanbury Brown-Twiss effect Scattering Born approximation Quasi-homogeneous media Inverse scattering a b scattering media, is studied by the use of the Hanbury Brown­Twiss effect. In particular the two

  16. Space-time BIE methods for non homogeneous exterior wave equation problems. The Dirichlet case.

    E-Print Network [OSTI]

    Ceragioli, Francesca

    Space-time BIE methods for non homogeneous exterior wave equation problems. The Dirichlet case. S. Falletta , G. Monegato , L. Scuderi§ Abstract In this paper we consider the (2D and 3D) exterior problem; non homogeneous conditions; space-time boundary integral equations; numerical methods This work

  17. Data-driven Techniques to Estimate Parameters in the Homogenized Energy Model for Shape Memory Alloys

    E-Print Network [OSTI]

    Data-driven Techniques to Estimate Parameters in the Homogenized Energy Model for Shape Memory. In this paper, we focus on the homogenized energy model for shape memory alloys (SMA). Specifically, we develop parameters are compared to the initial estimates. 1 Introduction Shape memory alloys (SMA) are novel

  18. Near Optimal Broadcast with Network Coding in Large Homogeneous Wireless Sensor Networks

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Near Optimal Broadcast with Network Coding in Large Homogeneous Wireless Sensor Networks C of wireless "homogeneous" sensor networks contained of the plane: wireless lattice networks, and dense unit of application is wireless sensor net- works, and indeed network coding has been used in wireless networks

  19. Mechanisms of Homogeneous Nucleation of Polymers of Sickle Cell Anemia Hemoglobin in Deoxy State

    E-Print Network [OSTI]

    Vekilov, Peter

    Mechanisms of Homogeneous Nucleation of Polymers of Sickle Cell Anemia Hemoglobin in Deoxy State, TX 77204-4004, USA The primary pathogenic event of sickle cell anemia is the polymerization reserved. Keywords: sickle cell anemia; hemoglobin S polymerization; fiber nucleation; homogeneous

  20. Unsteady Flow Evolution and Combustion Dynamics of Homogeneous Solid Propellant in a Rocket Motor

    E-Print Network [OSTI]

    Apte, Sourabh V.

    Unsteady Flow Evolution and Combustion Dynamics of Homogeneous Solid Propellant in a Rocket Motor University, University Park, PA 16802, USA A time-resolved numerical analysis of combustion dynamics of double-base homogenous solid propellant in a rocket motor is performed by means of a Large

  1. Homogeneous, dual layer, solid state, thin film deposition for structural and/or electrochemical characteristics

    DOE Patents [OSTI]

    Pitts, J. Roland; Lee, Se-Hee; Tracy, C. Edwin; Li, Wenming

    2014-04-08T23:59:59.000Z

    Solid state, thin film, electrochemical devices (10) and methods of making the same are disclosed. An exemplary device 10 includes at least one electrode (14) and an electrolyte (16) deposited on the electrode (14). The electrolyte (16) includes at least two homogenous layers of discrete physical properties. The two homogenous layers comprise a first dense layer (15) and a second porous layer (16).

  2. Scheduling Parallel Task Graphs on (Almost) Homogeneous Multi-cluster Platforms

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Scheduling Parallel Task Graphs on (Almost) Homogeneous Multi-cluster Platforms Pierre these applications efficiently on parallel platforms has been a long-standing challenge. In the case of a single homogeneous platform, such as a cluster, results have been obtained both in theory, i.e., guaranteed

  3. The building blocks of dynamical heterogeneities in dense granular media

    E-Print Network [OSTI]

    R. Candelier; O. Dauchot; G. Biroli

    2009-01-22T23:59:59.000Z

    We investigate experimentally the connection between short time dynamics and long time dynamical heterogeneities within a dense granular media under cyclic shear. We show that dynamical heterogeneities result from a two timescales process. Short time but already collective events consisting in clustered cage jumps concentrate most of the non affine displacements. On larger timescales such clusters appear aggregated both temporally and spatially in avalanches which eventually build the large scales dynamical heterogeneities. Our results indicate that facilitation plays an important role in the relaxation process although it does not appear to be conserved as proposed in many models studied in the literature.

  4. Development of K-Basin High-Strength Homogeneous Sludge Simulants and Correlations Between Unconfined Compressive Strength and Shear Strength

    SciTech Connect (OSTI)

    Onishi, Yasuo; Baer, Ellen BK; Chun, Jaehun; Yokuda, Satoru T.; Schmidt, Andrew J.; Sande, Susan; Buchmiller, William C.

    2011-02-20T23:59:59.000Z

    K-Basin sludge will be stored in the Sludge Transport and Storage Containers (STSCs) at an interim storage location on Central Plateau before being treated and packaged for disposal. During the storage period, sludge in the STSCs may consolidate/agglomerate, potentially resulting in high-shear-strength material. The Sludge Treatment Project (STP) plans to use water jets to retrieve K-Basin sludge after the interim storage. STP has identified shear strength to be a key parameter that should be bounded to verify the operability and performance of sludge retrieval systems. Determining the range of sludge shear strength is important to gain high confidence that a water-jet retrieval system can mobilize stored K-Basin sludge from the STSCs. The shear strength measurements will provide a basis for bounding sludge properties for mobilization and erosion. Thus, it is also important to develop potential simulants to investigate these phenomena. Long-term sludge storage tests conducted by Pacific Northwest National Laboratory (PNNL) show that high-uranium-content K-Basin sludge can self-cement and form a strong sludge with a bulk shear strength of up to 65 kPa. Some of this sludge has 'paste' and 'chunks' with shear strengths of approximately 3-5 kPa and 380-770 kPa, respectively. High-uranium-content sludge samples subjected to hydrothermal testing (e.g., 185 C, 10 hours) have been observed to form agglomerates with a shear strength up to 170 kPa. These high values were estimated by measured unconfined compressive strength (UCS) obtained with a pocket penetrometer. Due to its ease of use, it is anticipated that a pocket penetrometer will be used to acquire additional shear strength data from archived K-Basin sludge samples stored at the PNNL Radiochemical Processing Laboratory (RPL) hot cells. It is uncertain whether the pocket penetrometer provides accurate shear strength measurements of the material. To assess the bounding material strength and potential for erosion, it is important to compare the measured shear strength to penetrometer measurements and to develop a correlation (or correlations) between UCS measured by a pocket penetrometer and direct shear strength measurements for various homogeneous and heterogeneous simulants. This study developed 11 homogeneous simulants, whose shear strengths vary from 4 to 170 kPa. With these simulants, we developed correlations between UCS measured by a Geotest E-280 pocket penetrometer and shear strength values measured by a Geonor H-60 hand-held vane tester and a more sophisticated bench-top unit, the Haake M5 rheometer. This was achieved with side-by-side measurements of the shear strength and UCS of the homogeneous simulants. The homogeneous simulants developed under this study consist of kaolin clay, plaster of Paris, and amorphous alumina CP-5 with water. The simulants also include modeling clay. The shear strength of most of these simulants is sensitive to various factors, including the simulant size, the intensity of mixing, and the curing time, even with given concentrations of simulant components. Table S.1 summarizes these 11 simulants and their shear strengths.

  5. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOE Patents [OSTI]

    Angelici, R.J.; Gao, H.

    1998-08-04T23:59:59.000Z

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilication, olefin oxidation, isomerization, hydrocyanidation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical. 2 figs.

  6. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOE Patents [OSTI]

    Angelici, Robert J. (Ames, IA); Gao, Hanrong (Ames, IA)

    1998-08-04T23:59:59.000Z

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilation, olefin oxidation, isomerization, hydrocyanation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical.

  7. Crystal Structure of 12-Lipoxygenase Catalytic-Domain-Inhibitor Complex Identifies a Substrate-Binding Channel for Catalysis

    SciTech Connect (OSTI)

    Xu, Shu; Mueser, Timothy C.; Marnett, Lawrence J.; Funk, Jr., Max O. (Toledo); (Vanderbilt)

    2014-10-02T23:59:59.000Z

    Lipoxygenases are critical enzymes in the biosynthesis of families of bioactive lipids including compounds with important roles in the initiation and resolution of inflammation and in associated diseases such as diabetes, cardiovascular disease, and cancer. Crystals diffracting to high resolution (1.9 {angstrom}) were obtained for a complex between the catalytic domain of leukocyte 12-lipoxygenase and the isoform-specific inhibitor, 4-(2-oxapentadeca-4-yne)phenylpropanoic acid (OPP). In the three-dimensional structure of the complex, the inhibitor occupied a new U-shaped channel open at one end to the surface of the protein and extending past the redox-active iron site that is essential for catalysis. In models, the channel accommodated arachidonic acid, defining the binding site for the substrate of the catalyzed reaction. There was a void adjacent to the OPP binding site connecting to the surface of the enzyme and providing a plausible access channel for the other substrate, oxygen.

  8. Metal carbonyl-hydrosilane reactions and hydrosilation catalysis. Final report for period May 1, 1995 - August 14, 1999

    SciTech Connect (OSTI)

    Cutler, Alan R.

    2001-04-14T23:59:59.000Z

    Manganese carbonyl complexes serve as hydrosilation precatalysts for selectively transforming a carbonyl group into a doxy methylene or a fully reduced methylene group. Substrates of interest include (1) aldehydes, ketones, carboxylic acids, silyl esters, and esters, and (2) their organometallic acyl counterparts. Two types of manganese precatalysts have been reported: (a) alkyl and acyl complexes (L)(CO){sub 4}MnR [L = CO, PPh{sub 3}; R = COCH{sub 3}, COPh, CH{sub 3}] and (b) halides (CO){sub 5}MnX and [(CO){sub 4}MnX]{sub 2} (X = Br, I). The former promote hydrosilation and deoxygenation catalysis; the latter promote dehydrogenative silation of alcohols and carboxylic acids as well as hydrosilation and deoxygenation of some metallocarboxylic acid derivatives. In every case studied, these Mn precatalysts are far more reactive or selective than traditional Rh(l) precatalysts. The reaction chemistry of the above and other Mn alkyl complexes with hydrosilanes was studied in order to probe catalysis mechanism(s). Thus, Mn(CO){sub 5} methyl, benzyl, acetyl, and benzoyl (4 p-substituents) complexes reacted with hydrosilines by four different mechanisms, which were established. A noteworthy development was that the methyl and benzoyl complexes gave moderate yields of a new ({eta}{sup 2}-Si-H) silane adduct (CO){sub 4}Mn(SiMe{sub 2}Ph)(H-SiMe{sub 2}Ph), which is stable in the presence of excess silane. This silane adduct promotes all three catalytic reactions; its extraordinary activity and potential selectivity are under study.

  9. High Efficiency, Low Emissions Homogeneous Charge Compression Ignition (HCCI) Engines

    SciTech Connect (OSTI)

    None

    2011-01-31T23:59:59.000Z

    This is the final report of the High Efficiency Clean Combustion (HECC) Research Program for the U.S. Department of Energy. Work under this co-funded program began in August 2005 and finished in July 2010. The objective of this program was to develop and demonstrate a low emission, high thermal efficiency engine system that met 2010 EPA heavy-duty on-highway truck emissions requirements (0.2g/bhp-hr NOx, 0.14g/bhp-hr HC and 0.01g/bhp-hr PM) with a thermal efficiency of 46%. To achieve this goal, development of diesel homogenous charge compression ignition (HCCI) combustion was the chosen approach. This report summarizes the development of diesel HCCI combustion and associated enabling technologies that occurred during the HECC program between August 2005 and July 2010. This program showed that although diesel HCCI with conventional US diesel fuel was not a feasible means to achieve the program objectives, the HCCI load range could be increased with a higher volatility, lower cetane number fuel, such as gasoline, if the combustion rate could be moderated to avoid excessive cylinder pressure rise rates. Given the potential efficiency and emissions benefits, continued research of combustion with low cetane number fuels and the effects of fuel distillation are recommended. The operation of diesel HCCI was only feasible at part-load due to a limited fuel injection window. A 4% fuel consumption benefit versus conventional, low-temperature combustion was realized over the achievable operating range. Several enabling technologies were developed under this program that also benefited non-HCCI combustion. The development of a 300MPa fuel injector enabled the development of extended lifted flame combustion. A design methodology for minimizing the heat transfer to jacket water, known as precision cooling, will benefit conventional combustion engines, as well as HCCI engines. An advanced combustion control system based on cylinder pressure measurements was developed. A Well-to-wheels analysis of the energy flows in a mobile vehicle system and a 2nd Law thermodynamic analysis of the engine system were also completed under this program.

  10. Quantitative tumor heterogeneity assessment on a nuclear population

    E-Print Network [OSTI]

    Quantitative tumor heterogeneity assessment on a nuclear population basis Anne-Sofie Wessel score in this area was performed. 110 of the 226 TMA cores were scored by a pathologist. The automatic

  11. Well Productivity Enhancement of High Temperature Heterogeneous Carbonate Reservoirs

    E-Print Network [OSTI]

    Wang, Guanqun

    2014-05-08T23:59:59.000Z

    Acidizing is one of the most popular techniques for well productivity enhancement during oil and gas production. However, the treatment method is not very effective when the wellbore penetrates through multiple layers of heterogeneous reservoirs...

  12. Heterogeneous-race-free Memory Models Derek R. Hower

    E-Print Network [OSTI]

    Wood, David A.

    1 Heterogeneous-race-free Memory Models Derek R. Hower , Blake A. Hechtman§ , Bradford M. Beckmann Electrical and Computer Engineering University of Wisconsin-Madison Computer Sciences {derek.hower, brad

  13. Structure, Thermodynamics and Kinetics of Chemically Heterogeneous Interfaces

    E-Print Network [OSTI]

    Palafox Hernandez, Jesus Pablo

    2011-08-31T23:59:59.000Z

    ), and a metal alloy interface (Cu-Pb). In both systems, interfacial prefreezing (crystal formation above the melting point of the fluid) was observed and this prefreezing was seen to promote heterogeneous nucleation, when the systems were cooled below...

  14. An Intelligent Threat Prevention Framework with Heterogeneous Information

    E-Print Network [OSTI]

    Liu, Weiru

    An Intelligent Threat Prevention Framework with Heterogeneous Information Wenjun Ma 1 and Weiru Liu 1 Abstract. Three issues usually are associated with threat prevention intelligent surveillance, the de- mand of effectively predicting suspects' intention and ranking the potential threats posed

  15. The Yin and Yang of Hardware Heterogeneity: Can Software Survive?

    E-Print Network [OSTI]

    McKinley, Kathryn S.

    The Yin and Yang of Hardware Heterogeneity: Can Software Survive? Kathryn S. McKinley Microsoft- ingly choose high-level managed programming languages with safe pointer disciplines, garbage collection

  16. Discrete Feature Approach for Heterogeneous Reservoir Production Enhancement

    SciTech Connect (OSTI)

    Dershowitz, William S.; Curran, Brendan; Einstein, Herbert; LaPointe, Paul; Shuttle, Dawn; Klise, Kate

    2002-07-26T23:59:59.000Z

    The report presents summaries of technology development for discrete feature modeling in support of the improved oil recovery (IOR) for heterogeneous reservoirs. In addition, the report describes the demonstration of these technologies at project study sites.

  17. PARTITIONED ANALYSIS FOR DIMENSIONALLY-HETEROGENEOUS HYDRAULIC NETWORKS*

    E-Print Network [OSTI]

    Buscaglia, Gustavo C.

    PARTITIONED ANALYSIS FOR DIMENSIONALLY-HETEROGENEOUS HYDRAULIC NETWORKS* JORGE S. LEIVA , PABLO J for which this procedure is envisaged arises when modeling hydraulic networks in which complex and simple

  18. Magnetically-Assisted Statistical Assembly - a new heterogeneous integration technique

    E-Print Network [OSTI]

    Fonstad, Clifton G. Jr.

    This paper presents a new technique for the monolithic heterogeneous integration of compound semiconductor devices with silicon integrated circuits, and establishes the theoretical foundation for a key element of the ...

  19. Increasing Stability Reduces Conformational Heterogeneity in a Protein Folding

    E-Print Network [OSTI]

    Increasing Stability Reduces Conformational Heterogeneity in a Protein Folding Intermediate, the results show that protein folding intermediates are ensembles of different structural forms direct experi- mental evidence in support of a basic tenet of energy landscape theory for protein folding

  20. Entrainment of heterogeneous glycolytic oscillations in single cells

    E-Print Network [OSTI]

    Gustavsson, A -K; Mehlig, B; Goksör, M

    2015-01-01T23:59:59.000Z

    Cell signaling, gene expression, and metabolism are affected by cell-cell heterogeneity and random changes in the environment. The effects of such fluctuations on cell signaling and gene expression have recently been studied intensively using single-cell experiments. In metabolism heterogeneity may be particularly important because it may affect synchronisation of metabolic oscillations, an important example of cell-cell communication. This synchronisation is notoriously difficult to describe theoretically as the example of glycolytic oscillations shows: neither is the mechanism of glycolytic synchronisation understood nor the role of cell-cell heterogeneity. To pin down the mechanism and to assess its robustness and universality we have experimentally investigated the entrainment of glycolytic oscillations in individual yeast cells by periodic external perturbations. We find that oscillatory cells synchronise through phase shifts and that the mechanism is insensitive to cell heterogeneity (robustness) and si...

  1. Heterogeneous-k-core versus Bootstrap Percolation on Complex Networks

    E-Print Network [OSTI]

    G. J. Baxter; S. N. Dorogovtsev; A. V. Goltsev; J. F. F. Mendes

    2010-12-20T23:59:59.000Z

    We introduce the heterogeneous-$k$-core, which generalizes the $k$-core, and contrast it with bootstrap percolation. Vertices have a threshold $k_i$ which may be different at each vertex. If a vertex has less than $k_i$ neighbors it is pruned from the network. The heterogeneous-$k$-core is the sub-graph remaining after no further vertices can be pruned. If the thresholds $k_i$ are $1$ with probability $f$ or $k \\geq 3$ with probability $(1-f)$, the process forms one branch of an activation-pruning process which demonstrates hysteresis. The other branch is formed by ordinary bootstrap percolation. We show that there are two types of transitions in this heterogeneous-$k$-core process: the giant heterogeneous-$k$-core may appear with a continuous transition and there may be a second, discontinuous, hybrid transition. We compare critical phenomena, critical clusters and avalanches at the heterogeneous-$k$-core and bootstrap percolation transitions. We also show that network structure has a crucial effect on these processes, with the giant heterogeneous-$k$-core appearing immediately at a finite value for any $f > 0$ when the degree distribution tends to a power law $P(q) \\sim q^{-\\gamma}$ with $\\gamma < 3$.

  2. The heterogeneous gas with singular interaction: Generalized circular law and heterogeneous renormalized energy

    E-Print Network [OSTI]

    Luis Carlos Garcia del Molino; Khashayar Pakdaman; Jonathan Touboul

    2014-10-26T23:59:59.000Z

    We introduce and analyze $d$ dimensional Coulomb gases with random charge distribution and general external confining potential. We show that these gases satisfy a large deviations principle. The analysis of the minima of the rate function (which is the leading term of the energy) reveals that at equilibrium, the particle distribution is a generalized circular law (i.e. with spherical support but non-necessarily uniform distribution). In the classical electrostatic external potential, there are infinitely many minimizers of the rate function. The most likely macroscopic configuration is a disordered distribution in which particles are uniformly distributed (for $d=2$, the circular law), and charges are independent of the positions of the particles. General charge-dependent confining potentials unfold this degenerate situation: in contrast, the particle density is not uniform, and particles spontaneously organize according to their charge. In that picture the classical electrostatic potential appears as a transition at which order is lost. Sub-leading terms of the energy are derived: we show that these are related to an operator, generalizing the Coulomb renormalized energy, which incorporates the heterogeneous nature of the charges. This heterogeneous renormalized energy informs us about the microscopic arrangements of the particles, which are non-standard, strongly depending on the charges, and include progressive and irregular lattices.

  3. Line-tension-induced scenario of heterogeneous nucleation on a spherical substrate and in a spherical cavity

    E-Print Network [OSTI]

    Masao Iwamatsu

    2015-06-19T23:59:59.000Z

    Line-tension-induced {scenario of heterogeneous nucleation} is studied for a lens-shaped nucleus with a finite contact angle nucleated on a spherical substrate and on the bottom of the wall of a spherical cavity. The effect of line tension on the free energy of a critical nucleus can be separated from the usual volume term. By comparing the free energy of a lens-shaped critical nucleus of a finite contact angle with that of a spherical nucleus, we find that a spherical nucleus may have a lower free energy than a lens-shaped nucleus when the line tension is positive and large, which is similar to the drying transition predicted by Widom [B. Widom, J. Phys. Chem. {\\bf 99} 2803 (1995)]. Then, the homogeneous nucleation rather than the heterogeneous nucleation will be favorable. Similarly, the free energy of a lens-shaped nucleus becomes negative when the line tension is negative and large. Then, the barrier-less nucleation with no thermal activation called athermal nucleation will be realized.

  4. Research of a boundary condition quantifiable correction method in the assembly homogenization

    SciTech Connect (OSTI)

    Peng, L. H.; Liu, Z. H.; Zhao, J. [Inst. of Nuclear and New Energy Technology, Tsinghua Univ., Beijing, 100084 (China); Li, W. H. [China Nuclear Power Technology Research Inst., Shenzhen, 518026 (China)

    2012-07-01T23:59:59.000Z

    The methods and codes currently used in assembly homogenization calculation mostly adopt the reflection boundary conditions. The influences of real boundary conditions on the assembly homogenized parameters were analyzed. They were summarized into four quantifiable effects, and then the mathematical expressions could be got by linearization hypothesis. Through the calculation of a test model, it had been found that the result was close to transport calculation result when considering four boundary quantifiable effects. This method would greatly improve the precision of a core design code which using the assembly homogenization methods, but without much increase of the computing time. (authors)

  5. Effect of homogenization pressure and milk composition on some physical properties of yogurt

    E-Print Network [OSTI]

    Lin, Chun-An

    1995-01-01T23:59:59.000Z

    (Fig. 7). The increase in firmness due to increased MF concentration was not linear. The increase in firmness that was observed when the MF concentration of the yogurt was increased &om 2 to 4% was much greater than the increase in firmness when MF...) Figure 6. Effect of homogenization pressure (HP) and solids-not-fat (SNF) on the firmness of yogurt. 25 120 4% MF 110 100 90 2% MF 80 70 0% MF 60 3000 6000 9000 12000 15000 Homogenization pressure (psi) Figure 7. Effect of homogenization...

  6. Neutronic Assessment of Transmutation Target Compositions in Heterogeneous Sodium Fast Reactor Geometries

    SciTech Connect (OSTI)

    Samuel E. Bays; Rodolfo M. Ferrer; Michael A. Pope; Benoit Forget; Mehdi Asgari

    2008-02-01T23:59:59.000Z

    The sodium fast reactor is under consideration for consuming the transuranic waste in the spent nuclear fuel generated by light water reactors. This work is concerned with specialized target assemblies for an oxide-fueled sodium fast reactor that are designed exclusively for burning the americium and higher mass actinide component of light water reactor spent nuclear fuel (SNF). The associated gamma and neutron radioactivity, as well as thermal heat, associated with decay of these actinides may significantly complicate fuel handling and fabrication of recycled fast reactor fuel. The objective of using targets is to isolate in a smaller number of assemblies these concentrations of higher actinides, thus reducing the volume of fuel having more rigorous handling requirements or a more complicated fabrication process. This is in contrast to homogeneous recycle where all recycled actinides are distributed among all fuel assemblies. Several heterogeneous core geometries were evaluated to determine the fewest target assemblies required to burn these actinides without violating a set of established fuel performance criteria. The DIF3D/REBUS code from Argonne National Laboratory was used to perform the core physics and accompanying fuel cycle calculations in support of this work. Using the REBUS code, each core design was evaluated at the equilibrium cycle condition.

  7. Characterization of oil and gas reservoir heterogeneity; Final report, November 1, 1989--June 30, 1993

    SciTech Connect (OSTI)

    Sharma, G.D.

    1993-09-01T23:59:59.000Z

    The Alaskan North Slope comprises one of the Nation`s and the world`s most prolific oil province. Original oil in place (OOIP) is estimated at nearly 70 BBL (Kamath and Sharma, 1986). Generalized reservoir descriptions have been completed by the University of Alaska`s Petroleum Development Laboratory over North Slope`s major fields. These fields include West Sak (20 BBL OOIP), Ugnu (15 BBL OOIP), Prudhoe Bay (23 BBL OOIP), Kuparuk (5.5 BBL OOIP), Milne Point (3 BBL OOIP), and Endicott (1 BBL OOIP). Reservoir description has included the acquisition of open hole log data from the Alaska Oil and Gas Conservation Commission (AOGCC), computerized well log analysis using state-of-the-art computers, and integration of geologic and logging data. The studies pertaining to fluid characterization described in this report include: experimental study of asphaltene precipitation for enriched gases, CO{sup 2} and West Sak crude system, modeling of asphaltene equilibria including homogeneous as well as polydispersed thermodynamic models, effect of asphaltene deposition on rock-fluid properties, fluid properties of some Alaskan north slope reservoirs. Finally, the last chapter summarizes the reservoir heterogeneity classification system for TORIS and TORIS database.

  8. Characterizing Scattering by 3-D Arbitrarily Shaped Homogeneous Dielectric Objects Using Fast Multipole Method

    E-Print Network [OSTI]

    Li, Jian-Ying

    Electromagnetic scattering by 3-D arbitrarily shaped homogeneous dielectric objects is characterized. In the analysis, the method of moments is first employed to solve the combined field integral equation for scattering ...

  9. Dark energy homogeneity in general relativity: are we applying it correctly?

    E-Print Network [OSTI]

    Duniya, Didam

    2015-01-01T23:59:59.000Z

    Thusfar, there does not appear to be an agreed definition of homogeneous dark energy (DE). In this work, we argue that a correct definition of homogeneous DE is one whose density perturbation in comoving gauge vanishes. Using different DE models, we then investigate the consequence of this approach in the power spectrum -- with all the power spectra being normalized to match each other on small scales, at z = 0. We find that on super-Hubble scales, relativistic corrections in the observed galaxy power spectrum are able to distinguish a homogeneous DE from the concordance model and from a clustering DE, at low z and for high magnification bias. However, the matter power spectrum: is incapable of distinguishing a homogeneous DE from the concordance model (on all scales), at z = 0; but is able to differentiate it from a clustering DE, particularly at low z. Moreover, we found that relativistic effects become enhanced with decreasing magnification bias, and with increasing z.

  10. Thermodynamics In Einstein equation, the energy momentum tensor of homogeneous, isotropic

    E-Print Network [OSTI]

    Murayama, Hitoshi

    Thermodynamics In Einstein equation, the energy momentum tensor of homogeneous, isotropic fluid using the 1st law of thermodynamics, T = (U/S)V . Since U = V is expressed in terms of the temperature

  11. Homogeneous Factorisations of Graphs and Michael Giudici a, Cai Heng Li a

    E-Print Network [OSTI]

    Giudici, Michael

    Homogeneous Factorisations of Graphs and Digraphs Michael Giudici a, Cai Heng Li a Primoz Potocnik@maths.uwa.edu.au (Michael Giudici), li@maths.uwa.edu.au (Cai Heng Li), primoz.potocnik@fmf.uni-lj.si (Primoz Preprint

  12. Extension of the high load limit in the Homogeneous Charge Compression Ignition engine

    E-Print Network [OSTI]

    Scaringe, Robert J. (Robert Joseph)

    2009-01-01T23:59:59.000Z

    The Homogeneous Charge Compression Ignition (HCCI) engine offers diesel-like efficiency with very low soot and NOx emissions. In a HCCI engine, a premixed charge of air, fuel and burned gas is compressed to achieve ...

  13. Molecular simulation study of homogeneous crystal nucleation in n-alkane melts

    E-Print Network [OSTI]

    Yi, Peng, Ph. D. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    This work used molecular dynamics (MD) and Monte Carlo (MC) method to study the homogeneous crystal nucleation in the melts of n-alkanes, the simplest class of chain molecules. Three n-alkanes with progressive chain length ...

  14. RATE OF STRAIN TENSOR STATISTICS IN COMPRESSIBLE HOMOGENEOUS G. Erlebacher 1 , S. Sarkar 1

    E-Print Network [OSTI]

    Erlebacher, Gordon

    RATE OF STRAIN TENSOR STATISTICS IN COMPRESSIBLE HOMOGENEOUS TURBULENCE G. Erlebacher 1 , S. Sarkar was determined in Sarkar, Erlebacher and Hus­ saini (ref. 2) to be due to enhanced compressible dis­ sipation

  15. An investigation into the properties and characteristics of homogeneous tapered cables

    E-Print Network [OSTI]

    deCastongrene, Russell Othomar

    1975-01-01T23:59:59.000Z

    AN INVESTIGATION INTO THE PROPERTIES AND CHABACTEBISTICS OF HOMOGENEOUS TAPL'BED CABLES A Thesis by RUSSELL OTHOMAR deCASTONGBENE Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirement sor... the degree of MASTER OF SCIENCF. May 1975 Major Subject: Civil Engineering AN INVESTIGATION INTO THE PROPERTIES AND CHARACTERISTICS OF HOMOGENEOUS TAPERED CABLES A Thesis RUSSELL OTHOMAR deCASTONGRENE Approved as to style and content by: ( irman...

  16. Integration of geodesic flows on homogeneous spaces: the case of a wild lie group

    E-Print Network [OSTI]

    A. A. Magazev; I. V. Shirokov

    2007-03-21T23:59:59.000Z

    We obtain necessary and sufficient conditions for the integrability in quadratures of geodesic flows on homogeneous spaces $M$ with invariant and central metrics. The proposed integration algorithm consists in using a special canonical transformation in the space $T^*M$ based on constructing the canonical coordinates on the orbits of the coadjoint representation and on the simplectic sheets of the Poisson algebra of invariant functions. This algorithm is applicable to integrating geodesic flows on homogeneous spaces of a wild Lie group.

  17. The effect of temperature and homogenization pressure on enzymatic activity in cheese whey 

    E-Print Network [OSTI]

    Del Carmen, Maria Yanina

    1995-01-01T23:59:59.000Z

    THE EFFECT OF TEMPERATURE AND HOMOGENIZATION PRESSURE ON ENZYMATIC ACTIVITY IN CHEESE WHEY A Thesis by MARIA YANINA DEL CAWvKN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 1995 Major Subject; Food Science and Technology THE EFFECT OF TEMPERATURE AND HOMOGENIZATION PRESSURE ON ENZYMATIC ACTIVITY IN CHEESE WHEY A Thesis by MARIA YANINA DEL CARMEN Submitted to the Office of Graduate...

  18. The effect of temperature and homogenization pressure on enzymatic activity in cheese whey

    E-Print Network [OSTI]

    Del Carmen, Maria Yanina

    1995-01-01T23:59:59.000Z

    THE EFFECT OF TEMPERATURE AND HOMOGENIZATION PRESSURE ON ENZYMATIC ACTIVITY IN CHEESE WHEY A Thesis by MARIA YANINA DEL CAWvKN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE August 1995 Major Subject; Food Science and Technology THE EFFECT OF TEMPERATURE AND HOMOGENIZATION PRESSURE ON ENZYMATIC ACTIVITY IN CHEESE WHEY A Thesis by MARIA YANINA DEL CARMEN Submitted to the Office of Graduate...

  19. Two dimensional finite element analysis of homogenization and failure in plain weave textile composites

    E-Print Network [OSTI]

    Kondagunta, Veeraraghava Gopal

    1993-01-01T23:59:59.000Z

    TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA Submitted to the Office of Graduate Studies of Texas ARM University In partial fulffllment... of the requirements for the degree of MASTER OF SCIENCE August 1993 Major Subject: Aerospace Engineering TWO DIMENSIONAL FINITE ELEMENT ANALYSIS OF HOMOGENIZATION AND FAILURE IN PLAIN WEAVE TEXTILE COMPOSITES A Thesis by VEERARAGHAVA GOPAL KONDAGUNTA...

  20. Feedbacks between hydrological heterogeneity and bioremediation induced biogeochemical transformations

    SciTech Connect (OSTI)

    Englert, A.; Hubbard, S.S.; Williams, K.H.; Li, L.; Steefel, C.I.

    2009-04-15T23:59:59.000Z

    For guiding optimal design and interpretation of in-situ treatments that strongly perturb subsurface systems, knowledge about the spatial and temporal patterns of mass transport and reaction intensities are important. Here, a procedure was developed and applied to time-lapse concentrations of a conservative tracer (bromide), an injected amendment (acetate) and reactive species (iron(II), uranium(VI) and sulfate) associated with two field scale biostimulation experiments, which were conducted successively at the same field location over two years. The procedure is based on a temporal moment analysis approach that relies on a streamtube approximation. The study shows that biostimulated reactions can be considerably influenced by subsurface hydrological and geochemical heterogeneities: the delivery of bromide and acetate and the intensity of the sulfate reduction is interpreted to be predominantly driven by the hydrological heterogeneity, while the intensity of the iron reduction is interpreted to be primarily controlled by the geochemical heterogeneity. The intensity of the uranium(VI) reduction appears to be impacted by both the hydrological and geochemical heterogeneity. Finally, the study documents the existence of feedbacks between hydrological heterogeneity and remediation-induced biogeochemical transformations at the field scale, particularly the development of precipitates that may cause clogging and flow rerouting.