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Sample records for finely divided catalysts

  1. Identification of surface states on finely divided supported palladium catalysts by means of inelastic incoherent neutron scattering.

    PubMed

    Albers, Peter W; Krauter, Jürgen G E; Ross, D K; Heidenreich, Roland G; Köhler, Klaus; Parker, Stewart F

    2004-09-14

    The purpose of the present investigation was to utilize the inelastic incoherent neutron scattering (INS) technique to reveal changes at the surface of technical catalysts under the influence of hydrogen in gas/solid interactions and during chemical reactions in a liquid-phase process. The formation and the properties of supported palladium hydride and changes of the hydrogen-related surface chemistry of the corresponding activated carbon supports in 20% Pd/C catalysts after short-term and long-term hydrogen cycling at different hydrogen pressures and temperatures were studied. The spectra indicate that hydrogenation of the activated carbon support by hydrogen spillover occurs to, partly, give a material that strongly resembles a-C:H (amorphous hydrogenated carbon). Indications for different relaxation phenomena and long-range phase coherence inside of supported particles of palladium hydride compared to hydrogenated palladium black were obtained. A 5% Pd/C catalyst after use in C-C coupling reactions, the Heck reaction of bromobenzene and styrene to stilbenes, was also studied after subsequent solvent extraction. Evidence for a preferential adsorption and accumulation of cis-stilbene at the catalyst surface was obtained. INS allows identification of a certain isomer from a complex reaction mixture preferentially adsorbed at the surface of a finely divided industrial heterogeneous catalyst.

  2. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

  3. Fine particle clay catalysts for coal liquefaction

    SciTech Connect

    Olson, E.S.

    1991-01-01

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing. 5 refs., 1 tab.

  4. Combined method for simultaneously dewatering and reconstituting finely divided carbonaceous material

    SciTech Connect

    Wen, Wu-Wey; Deurbrouck, Albert W.

    1990-01-01

    A finely-divided carbonaceous material is dewatered and reconstituted in a combined process by adding a binding agent directly into slurry of finely divided material and dewatering the material to form a cake or consolidated piece which can be hardened by drying at ambient or elevated temperatures. Alternatively, the binder often in the form of a crusting agent is sprayed onto the surface of a moist cake prior to curing.

  5. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    NASA Astrophysics Data System (ADS)

    Afanasiev, Pavel

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoSx (x≈4) of 10-30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoSx under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS2 materials with very high pore volume and specific surface area, up to 0.45 cm3/g and 190 m2/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts.

  6. Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution

    SciTech Connect

    Afanasiev, Pavel

    2014-05-01

    Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoS{sub x} (x≈4) of 10–30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoS{sub x} under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS{sub 2} materials with very high pore volume and specific surface area, up to 0.45 cm{sup 3}/g and 190 m{sup 2}/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts. - Graphical abstract: Solution reaction in propylene carbonate allows preparing weakly agglomerated molybdenum sulfide with particle size 20 nm and advantageous catalytic properties. - Highlights: • Solution reaction in propylene carbonate yields MoS{sub x} particles near 20 nm size. • Addition of starch as capping agent reduces particles size and hinder agglomeration. • EXAFS at Mo K edge shows rapid oxygen to sulfur exchange in the solution. • Thermal treatment leads to MoS{sub 2} with very high porosity and surface area.

  7. Fine particle clay catalysts for coal liquefaction. Final technical report

    SciTech Connect

    Olson, E.S.

    1995-08-01

    In an effort to develop new disposable catalysts for direct coal liquefaction, several types of clay-supported pyrrhotite catalysts were prepared and tested. These included iron-pillared montmorillonite, mixed iron/alumina-pillared montmorillonite, iron-impregnated montmorillonite, and iron oxometallate-impregnated montmorillonite.

  8. Role of the resid solvent in catalytic coprocessing with finely divided catalysts. Final report

    SciTech Connect

    Curtis, C.W.

    1996-01-01

    The role of the resid in coprocessing coal with petroleum resid has been investigated using model systems. The primary question being investigated is whether resid is participating in reactions with coal or if the resid is acting simply as a diluent. Since hydrogen transfer is an important mechanism by which solvent interacts with coal, hydrogen transfer between naphthenes, saturated alicyclic molecules, that represent resid and aromatic molecules that represent coal were examined in reactions with a high pressure H{sub 2} atmosphere that is typical of actual coprocessing. The model naphthene, perhydropyrene, was chosen as the donor species and the models, anthracene, phenanthrene, and benzophenone, were chosen as the acceptor species. Coprocessing reactions of coal with petroleum resid were performed to evaluate the effect of the chemistry of both constituents on coal conversion and the upgrading of the heavy resid. Three heavy resids, Maya, FHC-623 and Manji were used as the whole resid and as fractions that has been separates into hexane solubles and saturate fractions.

  9. Fine particle clay catalysts for coal liquefaction. Quarterly technical report, May 9, 1991--August 8, 1991

    SciTech Connect

    Olson, E.S.

    1991-12-31

    The efficient production of environmentally acceptable distillate fuels requires catalysts for hydrogenation and cleavage of the coal macromolecules and removal of oxygen, nitrogen, and sulfur heteroatoms. The goal of the proposed research is to develop new catalysts for the direct liquefaction of coal. This type of catalyst consists of fine clay particles that have been treated with reagents which form pillaring structures between the aluminosilicate layers of the clay. The pillars not only hold the layers apart but also constitute the active catalytic sites for hydrogenation of the coal and the solvent used in the liquefaction. The pillaring catalytic sites are composed of pyrrhotite, which has been previously demonstrated to be active for coal liquefaction. The pyrrhotite sites are generated in situ by sulfiding the corresponding oxyiron species. The size of the catalyst will be less than 40 nm in order to promote intimate contact with the coal material. Since the clays and reagents for pillaring and activating the clays are inexpensive, the catalysts can be discarded after use, rather than regenerated by a costly process. The proposed work will evaluate methods for preparing the fine particle iron-pillared clay dispersions and for activating the particles to generate the catalysts. Characterization studies of the pillared clays and activated catalysts will be performed. The effectiveness of the pillared clay dispersion for hydrogenation and coal liquefaction will be determined in several types of testing.

  10. Nanostructured Mg-Al hydrotalcite as catalyst for fine chemical synthesis.

    PubMed

    Basahel, Sulaiman N; Al-Thabaiti, Shaeel A; Narasimharao, Katabathini; Ahmed, Nesreen S; Mokhtar, Mohamed

    2014-02-01

    This paper reviews the recent research of nanostructured Mg-Al hydrotalcite (Mg-Al HT) and its application as an efficient solid base catalyst for the synthesis of fine chemicals. Mg-Al HT has many beneficial features, such as low cost, selectivity, catalytic properties, and wide range of preparation and modification methods. They hold promise for providing sought-after, environmentally friendly technologies for the 21st century. Replacement of currently used homogeneous alkaline bases for the synthesis of fine chemicals by a solid catalyst can result in catalyst re-use and waste stream reduction. We introduce briefly the structure, properties and characterization of the nanostructured Mg-Al HT. The efficacy and benign applications of Mg-Al HT as an alternative solid base to homogenous catalysts in the synthesis of fine chemicals are then reviewed. The challenges for the future applications of Mg-Al HT in the synthesis of fine chemicals in terms of green protocol processes are discussed. PMID:24749466

  11. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  12. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-08-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. It has been shown that catalyst activity increases significantly with decreasing particle size for particle sizes in the submicron range. Ultra-fine catalyst particle generation will be accomplished using a novel two-step process. First, the severe conditions produced by a supercritical fluid (e.g., supercritical H{sub 2}O or CO{sub 2}) will be used to dissolve suitable catalyst compounds (e.g., Fe{sub 2}O{sub 3}, FeS{sub 2}, and/or Fe(CO){sub 5}). Sulfur containing compounds may be added to the supercritical solvent during catalyst dissolution to enhance the catalytic activity of the resulting ultra-fine, iron based, catalyst particles.

  13. Use of mesoporous MCM-41 aluminosilicates as catalysts in the production of fine chemicals: Preparation of dimethylacetals

    SciTech Connect

    Climent, M.J.; Corma, A.; Iborra, S.

    1996-07-01

    The authors prepared Dimethylacetals by reacting aldehydes with trimethyl orthoformate under catalytic conditions. MCM-41 mesoporous materials are found to be promising catalysts for their use in the production of fine chemicals. 13 refs., 6 figs., 4 tabs.

  14. Direct-contact heat exchanger for swirling countercurrent flow of hot gas and finely divided solids: A parametric study

    NASA Astrophysics Data System (ADS)

    Bell, K. J.; Arman, B.

    1991-06-01

    A vertically oriented solid-to-gas direct-contact heat exchanger (DCHX) has been proposed for heat recovery in high temperature plants that process finely divided solids. The flows are countercurrent, with the inlet gas flow entering on the centerline and swirling strongly. Swirling enhances heat transfer and centrifuges the solid particles from the center to the wall in order to minimize entrainment and permit gravity separation. A computer program was written to calculate particle trajectories and heat transfer rates (and, therefore, temperature profiles) for gas and solid phases. The flow model considers interactions between the particles and the flow field of the gas. The results of the computer program showed that the introduction of swirl significantly reduced the vertical distance required to achieve a given thermal efficiency. The countercurrent flow arrangement achieves high thermal efficiency in one contacting stage, unlike existing cocurrent suspension preheater systems, which require four or five stages. The practical application of this design to the cement industry appears unlikely, because very low gas velocities and correspondingly large areas of cross-sectional flow are required to prevent elutriation of the 74 micron particles required for the chemical reactions. The computer program can be modified for spray-dryer applications by the addition of mass transfer terms and a spray-formation model. In addition, the concept of a swirling flow heat exchanger may be applicable to other processes in which larger and heavier particles are used.

  15. Nanoscaled palladium catalysts on activated carbon support "Sibunit" for fine organic synthesis

    NASA Astrophysics Data System (ADS)

    Simakova, I.; Koskin, A.; Deliy, I.; Simakov, A.

    2005-08-01

    The application of nanosized palladium catalysts has gained growing importance over the last few years. Palladiumbased catalytic methods for fine organic synthesis permits the replacement of traditional labor-consuming techniques in multi-step organic syntheses and provides an improvement from the standpoint of cost and environmental impact. The use of activated carbon "Sibunit" as a substrate for catalysts has been fostered by the substrate's high surface area, chemical inertness both in acidic and basic media, and at the same time by the absence of very strong acidic centers on its surface which could promote undesirable side reactions during the catalytic run. A conversion of alpha-pinene derivatives to commercial biologically active compounds and fragrances as well as sun screens with ultra violet filtering properties, involves a catalytic hydrogenation as a key intermediate step. The aim of the present work is to clarify the factors favoring the dispersion of Pd metal on carbon. The effect of reduction temperature and pretreatment of the carbon surface on metal size during preparation of Pd on "Sibunit" catalysts for selective verbenol conversion was studied. The electron microscopy method (TEM) was used to show the influence on Pd metal dispersion of carbon surface oxidation by the oxidant H2O2, HNO3. The catalytic activity of Pd/C catalyst samples in verbenol hydrogenation reaction was determined. Kinetic peculiarities of verbenol hydrogenation over the most active catalyst sample were obtained.

  16. The role of the resid solvent in co-processing with finely divided catalysts. Quarterly report April--June 1993

    SciTech Connect

    Curtis, C.W.

    1993-11-01

    The primary purpose of the work performed this quarter was to establish under thermal and catalytic reaction conditions whether hydrogen transfer occurred between cycloalkane type structures that are present in resids and heteroatomic species that are present in coal and liquefied coal. The research this quarter focused upon evaluating benzophenone (BENZ) as a model acceptor for hydrogen that might be transferred from a cycloalkane, perhydropyrene (PHP), under coprocessing conditions. Hence, a number of reactions was performed in which BENZ was reacted alone in hydrogen and nitrogen atmospheres in the presence and absence of a catalytic agent, molybdenum naphthenate. Reactions were also performed using a combination of PHP and BENZ at a 1 to 1 weight ratio. Also performing this quarter were initial separations with petroleum resids. Two different resids were used, Maya and LHC-362. The literature was also surveyed to determine important characteristics that should be evaluated for selecting resids. The resids that are desired for this project are resids with high-, medium-, and low-naphthenic content. Different levels of asphaltenes are also desirable. Resids with these characteristics are currently being sought. The model compound PHP that had been commercially available as naphthene representative of resids is now no longer available. Hence, several scoping experiments were performed in order to determine conditions for synthesizing PHP. The synthesis procedure reported in US Patent 3,303,227 was used as a basis for this work. Although more than 85% PHP was synthesized, partially hydrogenated pyrenes were also produced which will require separation in order to obtain pure PHP.

  17. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

    SciTech Connect

    Klein, M.T.

    1991-12-30

    The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.

  18. METHOD OF PURIFYING CATALYSTS

    DOEpatents

    Joris, G.G.

    1958-09-01

    It has been fuund that the presence of chlorine as an impurity adversely affects the performance of finely divided platinum catalysts such as are used in the isotopic exchange process for the production of beavy water. This chlorine impurity may be removed from these catalysts by treating the catalyst at an elevated temperature with dry hydrogen and then with wet hydrogen, having a hydrogen-water vapor volume of about 8: 1. This alternate treatment by dry hydrogen and wet hydrogen is continued until the chlorine is largely removed from the catalyst.

  19. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ particle generation by rapid expansion of supercritical fluid solutions. Final technical report

    SciTech Connect

    Not Available

    1994-05-01

    The research conducted by Textron Defense Systems (TDS) represents a potential new and innovative concept for dispersed coal liquefaction. The technical approach is generation of ultra-fine catalyst particles from supercritical solutions by rapid expansion of either catalyst only, or mixtures of catalyst and coal material in supersaturated solvents. The process of rapid expansion of supercritical fluid solutions was developed at Battelle`s Pacific Northwest Laboratories for the intended purpose of providing a new analytical technique for characterizing supercritical fluids. The concept forming the basis of this research is that ultra-fine particles can be generated from supercritical solutions by rapid expansion of either catalyst or catalyst/coal-material mixtures in supersaturated solvents, such as carbon dioxide or water. The focal point of this technique is the rapid transfer of low vapor pressure solute (i.e., catalyst), dissolved in the supercritical fluid solvent, to the gas phase as the solution is expanded through an orifice. The expansion process is characterized by highly nonequilibrium conditions which cause the solute to undergo extremely rapid supersaturation with respect to the solvent, leading to nucleation and particle growth resulting in nanometer size catalyst particles. A supercritical expansion system was designed and built by TDS at their Haverhill facility.

  20. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction

    SciTech Connect

    Klein, M.T.

    1991-02-22

    The first task in our proposed study of catalysts for coal liquefaction was to prepare ultrafine dispersed metal sulfide particles by reactive precipitation from solutions of appropriate metal precursors. At this point, equipment to allow us to prepare these air-sensitive materials in an anaerobic environment has been acquired and assembled. Initial experiments aimed at synthesizing iron sulfide particles have been initiated. As part of the investigation of short contact time catalytic coal liquefaction, initial efforts focused on the noncatalytic pyrolysis reactions of coal and a model compound, Dibenzyl ether (DBE). Two different reactor configurations were examined; catalytic experiments are planned for the coming month.

  1. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, April 1, 1991--June 30, 1991

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  2. Microwave-assisted Extraction of Rare Earth Elements from Petroleum Refining Catalysts and Ambient Fine Aerosols Prior to Inductively Coupled Plasma - Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Kulkarni, Pranav; Chellam, Shankar

    2006-01-01

    In the absence of a certified reference material, a robust microwave-assisted acid digestion procedure followed by inductively coupled plasma - mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM2.5). High temperature (200 C), high pressure (200 psig), acid digestion (HNO3, HF, and H3BO3) with 20 minute dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst, and PM2.5. This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb, and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy, and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using 115In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu, and Dy in ambient PM2.5 in an industrial area of Houston, TX.

  3. Microwave-assisted extraction of rare earth elements from petroleum refining catalysts and ambient fine aerosols prior to inductively coupled plasma-mass spectrometry.

    PubMed

    Kulkarni, Pranav; Chellam, Shankararaman; Mittlefehldt, David W

    2007-01-01

    A robust microwave-assisted acid digestion procedure followed by inductively coupled plasma-mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM(2.5)). High temperature (200 degrees C), high pressure (200 psig), acid digestion (HNO(3), HF and H(3)BO(3)) with 20 min dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst and PM(2.5). This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using (115)In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu and Dy in ambient PM(2.5) in an industrial area of Houston, TX. PMID:17386451

  4. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, October 1, 1990--December 31, 1990

    SciTech Connect

    Not Available

    1991-08-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. It has been shown that catalyst activity increases significantly with decreasing particle size for particle sizes in the submicron range. Ultra-fine catalyst particle generation will be accomplished using a novel two-step process. First, the severe conditions produced by a supercritical fluid (e.g., supercritical H{sub 2}O or CO{sub 2}) will be used to dissolve suitable catalyst compounds (e.g., Fe{sub 2}O{sub 3}, FeS{sub 2}, and/or Fe(CO){sub 5}). Sulfur containing compounds may be added to the supercritical solvent during catalyst dissolution to enhance the catalytic activity of the resulting ultra-fine, iron based, catalyst particles.

  5. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, February 9, 1992--May 8, 1992

    SciTech Connect

    Olson, E.S.

    1995-10-01

    An investigation of new methods for the production of iron-pillared clay catalysts and clay-supported iron hydroxyoxide catalysts and the determination of their catalytic activities was continued in this quarter. Previous work in this project showed that a catalyst prepared by adding ferric nitrate and ammonia to an acid-washed clay gave an active catalyst following sulfidation. Further testing of this catalyst with a model compound showed that its hydrocracking activity was considerably lower when used in 10% concentration rather than 50%. In contrast, the mixed iron/alumina pillared clay catalysts were still highly effective at 10% concentration and gave good conversions at one and two hour reaction times. An investigation of preparation methods demonstrated that calcination of both the iron hydroxyoxide-impregnated clay and the mixed iron/alumina pillared clays is essential for activity. High activity was obtained for these catalysts only when they were removed from the aqueous media rapidly, dried, and calcined. The use of ferric sulfate to prepare a clay-supported sulfated iron catalyst was attempted, the resulting catalyst was relatively inactive for hydrocracking. Several new catalysts were synthesized with the idea of decreasing the pillar density and thereby increasing the micropore volume. A zirconia-pillared clay with low pillar density was prepared and intercalated with triiron complex. The hydrocracking activity of this catalyst was somewhat lower than that of the mixed alumina/iron-pillared catalyst. Other new catalysts, that were prepared by first pillaring with an organic ammonium pillaring agent, then introducing a lower number of silica or alumina pillars, and finally the iron component, were also tested. The mixed alumina/iron-pillared catalysts was further tested at low concentration for pyrene hydrogenating and hydrocracking activities.

  6. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, May 9, 1992--August 8, 1992

    SciTech Connect

    Olson, E.S.

    1995-10-01

    An investigation of new methods for the production of mixed pillared clay catalysts and clay-supported catalysts and determination of their catalytic activities were continued in this quarter. To demonstrate the reproducibility of the preparative method for high activity iron/alumina-pillared montmorillonite catalysts, a new batch of the catalyst was prepared and tested for hydrocracking activity with bibenzyl. This preparation gave conversion and product distribution similar to that reported previously. The mixed iron/alumina-pillared clay was also prepared using a pillaring solution that was aged for longer period of time. To determine the importance of the type of pillaring support in hydrocracking activity, iron/zirconia-pillared montmorillonite was prepared using the same technique as that for iron/alumina-pillared montmorillonite. The reaction of bibenzyl with the sulfided iron/zirconia-pillared catalyst gave a lower hydrocracking conversion than the iron/alumina-pillared catalyst. Addition of a second catalytic metal to the clay support was attempted to determine if a synergistic effect could improve liquefaction. Ferric nitrate and stannous chloride were added to the clay, but the resulting catalyst was relatively poor for hydrocracking and hydrogenation compared with ferric nitrate supported on the clay. New disposable iron catalysts with high acidity and surface area are desired for coal liquefaction. Synthetic iron aluminosilicates were prepared by methods similar to those used for the nickel-substituted synthetic mica montmorillonite (NiSMM) catalysts, which are very effective for hydrogenation and reforming of hydrocarbons. The iron aluminosilicate catalysts were tested for hydrocracking and hydrogenation of bibenzyl, naphthalene and pyrene. Pyrene hydrogenation was effectively catalyzed by the sulfided synthetic iron catalyst.

  7. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, May 8, 1993--August 8, 1993

    SciTech Connect

    Olson, E.S.

    1995-10-01

    High hydrocracking and liquefaction activity can be achieved with 10 wt.% of sulfided clay-supported iron catalysts. Further tests and demonstrations of this activity were required. Iron hydroxyoxide was generated on acid-treated montmorillonite. The new batch of catalyst exhibited high hydrocracking activity, Three hour tests with the solubilized intermediate from low-severity treatment of Wyodak coal (LSW) gave a high conversion (45%) of the heptane-insoluble LSW intermediate to heptane-soluble products. An investigation of new methods for the production of catalysts from tetralin-soluble iron oxometallates and the determination of their catalytic activities was continued in this quarter. Iron oxotitanate and iron oxoaluminate gave very high conversions of LSW to heptane solubles (61% and 54%, respectively). The high yields of heptane soluble products obtained with these catalysts offers a potential for use in liquefaction stages with solubilized coal, or at least serve as a model for producing active catalysts via mixed metal oxides. Methods for successfully testing dispersed iron catalysts with the low-severity intermediate were also devised. Catalyst recovered from the dispersed iron hydroxyoxide-catalyzed reaction of ion-exchanged Wyodak gave a high conversion (47%) of LSW to heptane solubles.

  8. Valley Divide

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03664 Valley Divide

    These small channels join to become Sabis Vallis.

    Image information: VIS instrument. Latitude -35.3N, Longitude 159.3E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  9. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, November 9, 1991--February 8, 1992

    SciTech Connect

    Olson, E.S.

    1995-10-01

    The investigation of methods for the production and testing of iron-pillared clay catalysts was continued in this quarter. The surface area of the mixed alumina/iron pillared clay catalyst decreased to 51 m{sup 2}/g on sulfidation. Thus the stability of the alumina pillars during the sulfidation and thermal treatments prevented the total collapse that occurred in the case of the iron-pillared clays. Previously the mixed alumina/iron pillared clays were tested for hydrocracking activities with bibenzyl. This testing was extended to a determination of activity with a second model compound substrate (pyrene), representative of the polynuclear aromatic systems present in coal. Testing of the mixed alumina/iron-pillared catalysts with 1-methylnaphthalene gave interesting results that demonstrate shape selectivity. The clay-supported iron hydroxyoxide catalysts prepared by impregnation of iron species on acidic clays were further investigated. Sulfidation of these catalysts using the carbon disulfide in situ method gave hydrocracking activities with bibenzyl that were somewhat less than those obtained by presulfidation with H{sub 2}/H{sub 2}S mixtures. Liquefaction of Wyodak subbituminous coal was very successful with the iron impregnated clay catalyst, giving a highly soluble product. High conversions were also obtained with the mixed alumina/iron-pillared clay catalyst, but the yield of oil-solubles was considerably lower. Several new catalysts were synthesized with the idea of decreasing the pillar density and thereby increasing the micropore volume. These catalysts were prepared by first pillaring with an organic ammonium pillaring agent, then introducing a lower number of silica or alumina pillars. Finally the iron component was added either before or after thermal removal of organic pillars.

  10. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, November 9, 1992--February 8, 1993

    SciTech Connect

    Olson, E.S.

    1995-10-01

    The mixed iron/alumina pillared clay catalysts and clay-supported iron catalysts have been shown in previous reports of this project to significantly improve yields of heptane-soluble products obtained in the liquefaction of both as received and acid-exchanged Wyodak subbituminous coal and Blind Canyon bituminous coal. In this quarter, the soluble product (LSW) obtained from the noncatalytic low-severity liquefaction of Wyodak coal was used as a feed to determine the activity of iron based catalysts for the hydrogenation and depolymerization steps. Comparison data for liquefaction of the soluble LSW with other catalysts were desired, and these data were obtained for a dispersed form of iron sulfide, prepared via iron hydroxyoxide (PETC method). The iron oxyhydroxide catalyst was directly precipitated on LSW product using either water or ethanol as the solvent. An insight into the functioning of the mixed iron/alumina pillared clay in coal liquefaction was investigated by preparing and studying an iron oxoaluminate structure. An investigation of new methods for the production of tetralin soluble iron oxometallate catalysts and the determination of their catalytic activities was continued in this quarter. The hydrogenation activity of iron oxoaluminate was investigated using pyrene and 1-methylnaphthalene as the test compounds, and results were compared with thermal reactions. In order to determine the loss of activity, recovered catalyst was recycled a second time for the hydrotreating of pyrene. Reaction of 1-methylnaphthalene with iron oxoaluminate also gave very high conversion to 1- and 5-methyltetralins and small amount of 2- and 6-methyltetralins. Liquefaction of Wyodak subbituminous and Blind Canyon bituminous coal was investigated using an in situ sulfided soluble iron oxoaluminate catalyst.

  11. Fine particle clay catalysts for coal liquefaction. Quarterly technical progress report, February 9, 1993--May 8, 1993

    SciTech Connect

    Olson, E.S.

    1995-10-01

    An investigation of new methods for the production and utilization of tetralin-soluble iron oxometallate precursors for coal liquefaction catalysts was continued in this quarter. Further descriptions of the catalytic activities of the sulfided forms were obtained. The hydrogenation activities of catalysts derived from iron oxotitanate and cobalt oxoaluminate were investigated using pyrene as a the test compound, and results were compared with thermal reactions. The hydrogenation activity of iron oxotitanate was superior to other catalysts including iron oxoaluminate. The hydrogenation activity of cobalt oxoaluminate was similar to that of iron oxoaluminate reported in previous quarterly report. The liquefaction of Wyodak subbituminous coal was investigated using in situ sulfided iron oxotitanate catalyst. In order to improve the usefulness of iron oxoaluminate as a liquefaction catalyst, iron oxoaluminate was supported on acid-treated montmorillonite (K-10). Supporting the iron oxoaluminate on an acidic support significantly improved the hydrogenation activity of iron oxoaluminate. The hydrocracking activity was increased by a large factor. Thus the aluminate and titanate structures surrounding the pyrrhotite that forms during sulfidation have a beneficial effect in preventing deactivation of the iron sites, and the presence of the acidic sites in the clay results in effective catalytic synergism between catalyst and support. These clay-supported iron oxometallates are highly promising catalysts for coal liquefaction. Iron oxyhydroxide and triiron supported on acid-treated montmorillonite (K-10) were tested for the liquefaction of ion-exchanged Wyodak (IEW) to minimize effects of the coal mineral matter. Both sulfided catalysts gave very high conversions of coal to THF-soluble and heptane-soluble (oils) products.

  12. PRELIMINARY IN-SITU X-RAY ABSORPTION FINE STRUCTURE EXAMINATION OF PT/C AND PTCO/C CATHODE CATALYSTS IN AN OPERATIONAL POLYMER ELECTROLYTE FUEL CELL

    SciTech Connect

    Phelan, B.T.; Myers, D.J.; Smith, M.C.

    2009-01-01

    State-of-the-art polymer electrolyte fuel cells require a conditioning period to reach optimized cell performance. There is insuffi cient understanding about the behavior of catalysts during this period, especially with regard to the changing environment of the cathode electrocatalyst, which is typically Pt nanoparticles supported on high surface area Vulcan XC-72 carbon (Pt/C). The purpose of this research was to record preliminary observations of the changing environment during the conditioning phase using X-Ray Absorption Fine Structure (XAFS) spectroscopy. XAFS was recorded for a Pt/C cathode at the Pt L3-edge and a PtCo/C cathode at both the Pt L3-edge and Co K-edge. Using precision machined graphite cell-blocks, both transmission and fl uorescence data were recorded at Sector 12-BM-B of Argonne National Laboratory’s Advanced Photon Source. The fl uorescence and transmission edge steps allow for a working description of the changing electrocatalyst environment, especially water concentration, at the anode and cathode as functions of operating parameters. These features are discussed in the context of how future analysis may correlate with potential, current and changing apparent thickness of the membrane electrode assembly through loss of catalyst materials (anode, cathode, carbon support). Such direct knowledge of the effect of the conditioning protocol on the electrocatalyst may lead to better catalyst design. In turn, this may lead to minimizing, or even eliminating, the conditioning period.

  13. Structural analysis of polymer-protected Pd/Pt bimetallic clusters as dispersed catalysts by using extended x-ray absorption fine structure spectroscopy

    SciTech Connect

    Toshima, Naoki; Harada, Masafumi; Yonezawa, Tetsu; Kushihashi, Kakuta; Asakura, Kiyotaka )

    1991-09-19

    Extended X-ray absorption fine structure (EXAFS) was applied to the determination of the structure of colloidal dispersions of the poly (N-vinyl-2-pyrrolidone)-protected palladium/platinum bimetallic clusters, which work as the catalysts for selective partial hydrogenation of 1,3-cyclooctadiene to cyclooctene. The catalytic activity was found to depend on the structure of the bimetallic clusters. The EXAFS data on the Pd/Pt (4/1) bimetallic clusters, which are the most active catalysts, indicate a Pt core structure, in which the 42 Pd atoms are on the surface of the cluster particle and 13 Pt atoms are at the center of the particle, forming a core. In contrast, the Pd/Pt (1/1) bimetallic clusters are suggested to have a modified Pt core structure, in which 28 Pt atoms connect directly with each other, being located both in the core and on the surface, and 27 Pd atoms form three islands on the surface of the cluster particle. These bimetallic clusters work as active catalysts for selective hydrogenation of olefins, selective partial hydrogenation of diene to monoene, and visible light-induced hydrogen generation from water.

  14. Catalyst suppliers consolidate further, offer more catalysts

    SciTech Connect

    Rhodes, A.K.

    1995-10-02

    The list of suppliers of catalysts to the petroleum refining industry has decreased by five since Oil and Gas Journal`s survey of refining catalysts and catalytic additives was last published. Despite the consolidation, the list of catalyst designations has grown to about 950 in this latest survey, compared to 820 listed in 1993. The table divides the catalysts by use and gives data on their primary differentiating characteristics, feedstock, products, form, bulk density,catalyst support, active agents, availability, and manufactures.

  15. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, October 25, 1990--October 24, 1991: Draft

    SciTech Connect

    Klein, M.T.

    1991-12-30

    The purpose of this work is to investigate the kinetics-assisted design, synthesis and characterization of fme-pardcle, unsupported catalysts for coal liquefaction. The goal is to develop a fundamental understanding of coal catalysis and catalysts that will, in turn, allow for the specification of a novel optimal catalyst for coal liquefaction.

  16. Method for dispersing catalyst onto particulate material

    DOEpatents

    Utz, Bruce R.; Cugini, Anthony V.

    1992-01-01

    A method for dispersing finely divided catalyst precursors onto the surface of coal or other particulate material includes the steps of forming a wet paste mixture of the particulate material and a liquid solution containing a dissolved transition metal salt, for instance a solution of ferric nitrate. The wet paste mixture is in a state of incipient wetness with all of this solution adsorbed onto the surfaces of the particulate material without the presence of free moisture. On adding a precipitating agent such as ammonia, a catalyst precursor such as hydrated iron oxide is deposited on the surfaces of the coal. The catalyst is activated by converting it to the sulfide form for the hydrogenation or direct liquefaction of the coal.

  17. Injection technology to recover nickel and cobalt from spent catalysts

    SciTech Connect

    Thapliyal, P.; Zhao, Y.F.; Irons, G.A.

    1996-12-31

    The petroleum refining industry generates over a million tons of spent catalyst per year, containing valuable metals. Currently, these materials are recycled to smelting furnaces, but the fundamental mechanisms controlling the recovery processes are poorly understood. Furthermore, submerged injection of finely divided materials is potentially a means to obtain high recoveries of pay metals. In this study, a catalyst containing 10% Ni and 1% Co was injected into 45 kg heats of matte. A copper matte was chosen so that the nickel and cobalt recoveries were measurable. It was found that the recovery ranged from 40 to 70%, increasing with catalyst feed rate, decreasing with catalyst particle size and decreasing with the oxygen content of the carrier gas. A mathematical model was developed to account for the results, and to permit extrapolation to nickel mattes. The industrial implications are discussed. 7 refs., 7 figs., 4 tabs.

  18. Optimization of reaction conditions in selective oxidation of styrene over fine crystallite spinel-type CaFe{sub 2}O{sub 4} complex oxide catalyst

    SciTech Connect

    Pardeshi, Satish K.; Pawar, Ravindra Y.

    2010-05-15

    The CaFe{sub 2}O{sub 4} spinel-type catalyst was synthesized by citrate gel method and well characterized by thermogravimetric analysis, atomic absorption spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and transmission electron microscopy. The crystallization temperature of the spinel particle prepared by citrate gel method was 600 {sup o}C which was lower than that of ferrite prepared by other methods. CaFe{sub 2}O{sub 4} catalysts prepared by citrate gel method show better activity for styrene oxidation in the presence of dilute H{sub 2}O{sub 2} (30%) as an oxidizing agent. In this reaction the oxidative cleavage of carbon-carbon double bond of styrene takes place selectively with 38 {+-} 2 mol% conversion. The major product of the reaction is benzaldehyde up to 91 {+-} 2 mol% and minor product phenyl acetaldehyde up to 9 {+-} 2 mol%, respectively. The products obtained in the styrene oxidation reaction were analyzed by gas chromatography and mass spectroscopy. The influence of the catalyst, reaction time, temperature, amount of catalyst, styrene/H{sub 2}O{sub 2} molar ratio and solvents on the conversion and product distribution were studied.

  19. Digital Leadership Divide

    ERIC Educational Resources Information Center

    Consortium for School Networking (NJ1), 2004

    2004-01-01

    This 2004 survey from the Consortium for School Networking (CoSN) and Grunwald Associates includes data from 455 school district decision-makers for technology. The report points to large and growing disparities in funding for school technology and questions if these differences signal a growing digital divide. The survey reveals, schools are…

  20. The nondeterministic divide

    NASA Technical Reports Server (NTRS)

    Charlesworth, Arthur

    1990-01-01

    The nondeterministic divide partitions a vector into two non-empty slices by allowing the point of division to be chosen nondeterministically. Support for high-level divide-and-conquer programming provided by the nondeterministic divide is investigated. A diva algorithm is a recursive divide-and-conquer sequential algorithm on one or more vectors of the same range, whose division point for a new pair of recursive calls is chosen nondeterministically before any computation is performed and whose recursive calls are made immediately after the choice of division point; also, access to vector components is only permitted during activations in which the vector parameters have unit length. The notion of diva algorithm is formulated precisely as a diva call, a restricted call on a sequential procedure. Diva calls are proven to be intimately related to associativity. Numerous applications of diva calls are given and strategies are described for translating a diva call into code for a variety of parallel computers. Thus diva algorithms separate logical correctness concerns from implementation concerns.

  1. Design, synthesis, and characterization of novel fine-particle, unsupported catalysts for coal liquefaction. Technical progress report, October 26, 1990--January 26, 1991: Draft

    SciTech Connect

    Klein, M.T.

    1991-02-22

    The first task in our proposed study of catalysts for coal liquefaction was to prepare ultrafine dispersed metal sulfide particles by reactive precipitation from solutions of appropriate metal precursors. At this point, equipment to allow us to prepare these air-sensitive materials in an anaerobic environment has been acquired and assembled. Initial experiments aimed at synthesizing iron sulfide particles have been initiated. As part of the investigation of short contact time catalytic coal liquefaction, initial efforts focused on the noncatalytic pyrolysis reactions of coal and a model compound, Dibenzyl ether (DBE). Two different reactor configurations were examined; catalytic experiments are planned for the coming month.

  2. Method for dispersing catalyst onto particulate material and product thereof

    DOEpatents

    Utz, Bruce R.; Cugini, Anthony V.

    1992-01-01

    A method for dispersing finely divided catalyst precursors onto the surface of coal or other particulate material includes the steps of forming a wet paste mixture of the particulate material and a liquid solution containing a dissolved transition metal salt, for instance a solution of ferric nitrate. The wet paste mixture is in a state of incipient wetness with all of this solution adsorbed onto the surfaces of the particulate material without the presence of free moisture. On adding a precipitating agent such as ammonia, a catalyst precursor such as hydrated iron oxide is deposited on the surfaces of the coal. The catalyst is activated by converting it to the sulfide form for the hydrogenation or direct liquefaction of the coal.

  3. Melting the Divide

    NASA Astrophysics Data System (ADS)

    Gibson, S. M.

    2014-12-01

    Presenting Quaternary Environmental Change to students who fall into Widening Participation criteria at the University of Cambridge, gives a unique opportunity to present academic debate in an approachable and entertaining way. Literally by discussing the melting of our ice caps, melts the divide Cambridge has between its reputation and the reality for the brightest, underprivileged, students. There is a balance between presenting cutting edge research with the need to come across as accessible (and importantly valuable to "learning"). Climate change over the Quaternary lends itself well to this aim. By lecturing groups of potential students through the entire Quaternary in an hour, stopping to discuss how our ancestors interacted with past Interglacials and what are the mechanisms driving change (in generalized terms), you are able to introduce cutting edge research (such as the latest NEEM ice core) to the students. This shows the evolution and importance of higher education and academic research. The lecture leads well onto group discussions (termed "supervisions" in Cambridge), to explore their opinions on the concern for present Anthropogenic Climate Change in relation to Past Climate Change after being presented with images that our ancestors "made it". Here discussion thrives off students saying obvious things (or sarcastic comments!) which quickly can lead into a deep technical discussion on their terms. Such discussions give the students a zest for higher education, simply throwing Ruddiman's (2003) "The Anthroprocene Started Several Thousand Years Ago" at them, questions in a second their concept of Anthropogenic Climate Change. Supervisions lend themselves well to bright, articulate, students and by offering these experiences to students of Widening Participation criteria we quickly melt the divide between the reputation of Cambridge ( and higher education as a whole) and the day to day practice. Higher education is not for the privileged, but a free and

  4. Divided electrochemical cell assembly

    SciTech Connect

    King, Ch. J. H.

    1985-02-19

    A divided electrochemical cell assembly comprises stacked bipolar substantially square parallel planar electrodes and membranes. The corners and edges of the electrodes with bordering insulative spacers in juxtaposition with the chamber walls define four electrolyte circulation manifolds. Anolyte and catholyte channeling means permit the separate introduction of anolyte and catholyte into two of the manifolds and the withdrawal of anolyte and catholyte separately from at least two other manifolds. The electrodes and membranes are separated from one another by the insulative spacers which are also channeling means disposed to provide electrolyte channels across the interfaces of adjacent electrodes and membranes.

  5. Monitoring the Digital Divide

    SciTech Connect

    Cottrell, Les

    2003-05-28

    It is increasingly important to support the large numbers of scientists working in remote areas and having low bandwidth access to the Internet. This will continue to be the case for years to come since there is evidence from PingER performance measurements that the, so-called, digital divide is not decreasing. In this work, we review the collaborative work of The Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, a leading organization promoting science dissemination in the developing world- and SLAC in Stanford, to monitor by PingER, Universities and Research Institutions all over the developing world following the recent ''Recommendations of Trieste'' to help bridge the digital divide. As a result, PingER's deployment now covers the real-time monitoring of worldwide Internet performance and, in particular, West and Central Africa for the first time. We report on the results from the ICTP sites and quantitatively identify regions with poor performance, identify trends, discuss experiences and future work.

  6. PULSE RATE DIVIDER

    DOEpatents

    McDonald, H.C. Jr.

    1962-12-18

    A compact pulse-rate divider circuit affording low impedance output and high input pulse repetition rates is described. The circuit features a single secondary emission tube having a capacitor interposed between its dynode and its control grid. An output pulse is produced at the anode of the tube each time an incoming pulse at the control grid drives the tube above cutoff and the duration of each output pulse corresponds to the charging time of the capacitor. Pulses incoming during the time the grid bias established by the discharging capacitor is sufficiently negative that the pulses are unable to drive the tube above cutoff do not produce output pulses at the anode; these pulses are lost and a dividing action is thus produced by the circuit. The time constant of the discharge path may be vanied to vary in turn the division ratio of the circuit; the time constant of the charging circuit may be varied to vary the width of the output pulses. (AEC)

  7. Why do bacteria divide?

    PubMed

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life - Life as independent of its constituents - is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass - its cellular connectivity - would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity - Life on the Scales of Equilibria - is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias 'hyperstructures.' The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence - Competitive Coherence - is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell's contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself. PMID:25932025

  8. Why do bacteria divide?

    PubMed

    Norris, Vic

    2015-01-01

    The problem of not only how but also why cells divide can be tackled using recent ideas. One idea from the origins of life - Life as independent of its constituents - is that a living entity like a cell is a particular pattern of connectivity between its constituents. This means that if the growing cell were just to get bigger the average connectivity between its constituents per unit mass - its cellular connectivity - would decrease and the cell would lose its identity. The solution is division which restores connectivity. The corollary is that the cell senses decreasing cellular connectivity and uses this information to trigger division. A second idea from phenotypic diversity - Life on the Scales of Equilibria - is that a bacterium must find strategies that allow it to both survive and grow. This means that it has learnt to reconcile the opposing constraints that these strategies impose. The solution is that the cell cycle generates daughter cells with different phenotypes based on sufficiently complex equilibrium (E) and non-equilibrium (NE) cellular compounds and structures appropriate for survival and growth, respectively, alias 'hyperstructures.' The corollary is that the cell senses both the quantity of E material and the intensity of use of NE material and then uses this information to trigger the cell cycle. A third idea from artificial intelligence - Competitive Coherence - is that a cell selects the active subset of elements that actively determine its phenotype from a much larger set of available elements. This means that the selection of an active subset of a specific size and composition must be done so as to generate both a coherent cell state, in which the cell's contents work together harmoniously, and a coherent sequence of cell states, each coherent with respect to itself and to an unpredictable environment. The solution is the use of a range of mechanisms ranging from hyperstructure dynamics to the cell cycle itself.

  9. Catalyst Chemical State during CO Oxidation Reaction on Cu(111) Studied with Ambient-Pressure X-ray Photoelectron Spectroscopy and Near Edge X-ray Adsorption Fine Structure Spectroscopy.

    PubMed

    Eren, Baran; Heine, Christian; Bluhm, Hendrik; Somorjai, Gabor A; Salmeron, Miquel

    2015-09-01

    The chemical structure of a Cu(111) model catalyst during the CO oxidation reaction in the CO+O2 pressure range of 10-300 mTorr at 298-413 K was studied in situ using surface sensitive X-ray photoelectron and adsorption spectroscopy techniques [X-ray photoelectron spectroscopy (XPS) and near edge X-ray adsorption fine structure spectroscopy (NEXAFS)]. For O2:CO partial pressure ratios below 1:3, the surface is covered by chemisorbed O and by a thin (∼1 nm) Cu2O layer, which covers completely the surface for ratios above 1:3 between 333 and 413 K. The Cu2O film increases in thickness and exceeds the escape depth (∼3-4 nm) of the XPS and NEXAFS photoelectrons used for analysis at 413 K. No CuO formation was detected under the reaction conditions used in this work. The main reaction intermediate was found to be CO2(δ-), with a coverage that correlates with the amount of Cu2O, suggesting that this phase is the most active for CO oxidation.

  10. Oxidation catalyst

    DOEpatents

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

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

  11. Highly Dispersed Metal Catalyst for Fuel Cell Electrodes

    SciTech Connect

    2009-03-01

    This factsheet describes a study that will bring industrial catalyst experience to fuel cell research. Specifically, industrial catalysts, such as those used in platforming, utilize precious metal platinum as an active component in a finely dispersed form.

  12. Essays on the Digital Divide

    ERIC Educational Resources Information Center

    Abdelfattah, Belal M. T.

    2013-01-01

    The digital divide is a phenomenon that is globally persistent, despite rapidly decreasing costs in technology. While much of the variance in the adoption and use of information communication technology (ICT) that defines the digital divide can be explained by socioeconomic and demographic variables, there is still significant unaccounted variance…

  13. DNA repair mechanisms in dividing and non-dividing cells

    PubMed Central

    Iyama, Teruaki; Wilson, David M.

    2013-01-01

    DNA damage created by endogenous or exogenous genotoxic agents can exist in multiple forms, and if allowed to persist, can promote genome instability and directly lead to various human diseases, particularly cancer, neurological abnormalities, immunodeficiency and premature aging. To avoid such deleterious outcomes, cells have evolved an array of DNA repair pathways, which carry out what is typically a multiple-step process to resolve specific DNA lesions and maintain genome integrity. To fully appreciate the biological contributions of the different DNA repair systems, one must keep in mind the cellular context within they operate. For example, the human body is composed of non-dividing and dividing cell types, including, in the brain, neurons and glial cells. We describe herein the molecular mechanisms of the different DNA repair pathways, and review their roles in non-dividing and dividing cells, with an eye towards how these pathways may regulate the development of neurological disease. PMID:23684800

  14. DNA repair mechanisms in dividing and non-dividing cells.

    PubMed

    Iyama, Teruaki; Wilson, David M

    2013-08-01

    DNA damage created by endogenous or exogenous genotoxic agents can exist in multiple forms, and if allowed to persist, can promote genome instability and directly lead to various human diseases, particularly cancer, neurological abnormalities, immunodeficiency and premature aging. To avoid such deleterious outcomes, cells have evolved an array of DNA repair pathways, which carry out what is typically a multiple-step process to resolve specific DNA lesions and maintain genome integrity. To fully appreciate the biological contributions of the different DNA repair systems, one must keep in mind the cellular context within which they operate. For example, the human body is composed of non-dividing and dividing cell types, including, in the brain, neurons and glial cells. We describe herein the molecular mechanisms of the different DNA repair pathways, and review their roles in non-dividing and dividing cells, with an eye toward how these pathways may regulate the development of neurological disease.

  15. Sociology: The growing climate divide

    NASA Astrophysics Data System (ADS)

    Hoffman, Andrew J.

    2011-07-01

    Climate change has reached the level of a 'scientific consensus', but is not yet a 'social consensus'. New analysis highlights that a growing divide between liberals and conservatives in the American public is a major obstacle to achieving this end.

  16. Process for combining the regeneratorless operation of tandem super-dense riser and fluid-bed oligomerization reactors containing a zeolite oligomerization catalyst

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1990-05-15

    This patent describes a catalytic process for upgrading a C{sub 2}{sup +} olefin feedstream to a heavier product stream rich in C{sub 10}{sup +} aliphatic hydrocarbons in first and second oligomerization zones. It comprises: contacting the olefin feedstream in the first zone with a finely divided medium pore size zeolite metallosilicate catalyst having a silica:alumina ratio grater than 12, and a constraint index in the range from about 1 to about 12, at a weight hourly space velocity (WHSV) sufficient to maintain a transport zone, and, then with essentially the same catalyst maintained as a fluid bed, the first zone containing riser catalyst having a higher coke content than that of catalyst in the second zone maintained in a turbulent regime.

  17. Supported molten-metal catalysts

    DOEpatents

    Datta, Ravindra; Singh, Ajeet; Halasz, Istvan; Serban, Manuela

    2001-01-01

    An entirely new class of catalysts called supported molten-metal catalysts, SMMC, which can replace some of the existing precious metal catalysts used in the production of fuels, commodity chemicals, and fine chemicals, as well as in combating pollution. SMMC are based on supporting ultra-thin films or micro-droplets of the relatively low-melting (<600.degree. C.), inexpensive, and abundant metals and semimetals from groups 1, 12, 13, 14, 15 and 16, of the periodic table, or their alloys and intermetallic compounds, on porous refractory supports, much like supported microcrystallites of the traditional solid metal catalysts. It thus provides orders of magnitude higher surface area than is obtainable in conventional reactors containing molten metals in pool form and also avoids corrosion. These have so far been the chief stumbling blocks in the application of molten metal catalysts.

  18. Fine Arts.

    ERIC Educational Resources Information Center

    Danzer, Gerald A.; Newman, Mark

    1992-01-01

    Discusses the use of fine arts as sources to enrich the study of history. Suggests that such works will serve as barometers of change, examples of cross-cultural influences, and political messages. Includes suggestions of works and artists from different historic periods. (DK)

  19. Dividing Fractions: A Pedagogical Technique

    ERIC Educational Resources Information Center

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  20. Getting Past the "Digital Divide"

    ERIC Educational Resources Information Center

    McCollum, Sean

    2011-01-01

    As most educators know, there is a lot more to addressing the so-called "digital divide" than having enough working machines in classrooms. Effective information technology (IT) in schools requires useful software, reliable and speedy Internet access, effective teacher training, and well-considered goals with transformative outcomes. Educators who…

  1. Getting Past the "Digital Divide"

    ERIC Educational Resources Information Center

    McCollum, Sean

    2011-01-01

    In the last decade, "digital divide" has become a catchphrase for the stubborn disparity in IT resources between communities, especially in regard to education. Low-income, rural and minority populations have received special scrutiny as the technological "have-nots." This article presents success stories of educators who can work around obstacles…

  2. Self-regeneration of a Pd-perovskite catalyst for automotive emissions control

    NASA Astrophysics Data System (ADS)

    Nishihata, Y.; Mizuki, J.; Akao, T.; Tanaka, H.; Uenishi, M.; Kimura, M.; Okamoto, T.; Hamada, N.

    2002-07-01

    Catalytic converters are widely used to reduce the amounts of nitrogen oxides, carbon monoxide and unburned hydrocarbons in automotive emissions. The catalysts are finely divided precious-metal particles dispersed on a solid support. During vehicle use, the converter is exposed to heat, which causes the metal particles to agglomerate and grow, and their overall surface area to decrease. As a result, catalyst activity deteriorates. The problem has been exacerbated in recent years by the trend to install catalytic converters closer to the engine, which ensures immediate activation of the catalyst on engine start-up, but also places demanding requirements on the catalyst's heat resistance. Conventional catalyst systems thus incorporate a sufficient excess of precious metal to guarantee continuous catalytic activity for vehicle use over 50,000miles (80,000km). Here we use X-ray diffraction and absorption to show that LaFe0.57Co0.38Pd0.05O3, one of the perovskite-based catalysts investigated for catalytic converter applications since the early 1970s, retains its high metal dispersion owing to structural responses to the fluctuations in exhaust-gas composition that occur in state-of-the-art petrol engines. We find that as the catalyst is cycled between oxidative and reductive atmospheres typically encountered in exhaust gas, palladium (Pd) reversibly moves into and out of the perovskite lattice. This movement appears to suppress the growth of metallic Pd particles, and hence explains the retention of high catalyst activity during long-term use and ageing.

  3. Wealth and the marital divide.

    PubMed

    Schneider, Daniel

    2011-09-01

    Marriage patterns differ dramatically in the United States by race and education. The author identifies a novel explanation for these marital divides, namely, the important role of personal wealth in marriage entry. Using event-history models and data from the National Longitudinal Survey of Youth 1979 cohort, the author shows that wealth is an important predictor of first marriage and that differences in asset ownership by race and education help to explain a significant portion of the race and education gaps in first marriage. The article also tests possible explanations for why wealth plays an important role in first marriage entry. PMID:22268248

  4. Characterisation of carbon supported platinum-ruthenium fuel cell catalysts of different degree of alloying

    NASA Astrophysics Data System (ADS)

    Albers, Peter W.; Weber, Winfried; Kunzmann, Kurt; Lopez, Marco; Parker, Stewart F.

    2008-12-01

    A series of PtRu/C fuel cell catalysts have been characterised by a combination of transmission electron microscopy, scanning transmission electron microscopy, energy dispersive X-ray microanalysis, X-ray diffraction and inelastic incoherent neutron scattering. The diffraction and microscopy studies show that a range of catalysts with different degrees of alloying can be obtained. It was possible to produce a strongly alloyed catalyst with average particle size below 10 nm. STEM/EDX results on the local compositions of the precious metal particles of different size and composition showed that the larger the particles the larger the Pt/Ru ratio. This indicates that ruthenium appears to prevent the agglomeration of the platinum particles to retain the smaller nanometer size. Inelastic neutron scattering spectroscopy shows that on the alloyed catalysts hydrogen occupies the threefold site, with no evidence for occupation of the on-top sites even under 800 mbar of hydrogen gas. Changes in the region of the out-of-plane C-H vibrational bands of the carbon black support indicated a contribution of the support during catalyst formation treatment by carbothermal reaction at lower temperature. Comparison of HREELS data from single crystal work and vibrational energy values from neutron spectroscopy allows to derive information on the site occupation of atomic hydrogen on finely divided precious metal particles supported on highly absorbing high surface area carbon blacks.

  5. Novel supports for coal liquefaction catalysts

    SciTech Connect

    Haynes, H.W. Jr.

    1992-01-01

    This research is divided into three parts: (1) Evaluation of Alkaline-Earth-Promoted CoMo/Alumina Catalysts in a Bench Scale Hydrotreater, (2) Development of a Novel Catalytic Coal Liquefaction Microreactor (CCLM) Unit, and (3) Evaluation of Novel Catalyst Preparations for Direct Coal Liquefaction. (VC)

  6. Bimetallic Catalysts.

    ERIC Educational Resources Information Center

    Sinfelt, John H.

    1985-01-01

    Chemical reaction rates can be controlled by varying composition of miniscule clusters of metal atoms. These bimetallic catalysts have had major impact on petroleum refining, where work has involved heterogeneous catalysis (reacting molecules in a phase separate from catalyst.) Experimentation involving hydrocarbon reactions, catalytic…

  7. A house divided cannot stand

    SciTech Connect

    Gilbert, S.M. )

    1994-01-01

    When it comes to the relationships between electric utilities and public service commissions, utilities would do well to remember the words of Abraham Lincoln -- [open quotes]A house divided against itself cannot stand.[close quotes] For just as distrust, dissension, and division threatened the future of the United States during the Civil War, they threaten the future of utilities today.In an effort to lower their costs and increase their competitive advantage, utility companies are increasingly looking to reinvent cultures, reengineer work processes, and redefine corporate missions, values, and strategies. But unless utilities also rebuild regulatory relations, such efforts are doomed to fail. If this prognosis sounds overly simplistic or melodramatic -- especially as utilities appear to be moving toward an era of reduced regulation -- think again. History shows that regulatory relationships drive a utility's ability to successfully integrate demand-side management (DSM) programs that are often critical to business strategies and goals.

  8. Oxyhydrochlorination catalyst

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1992-01-01

    An improved catalyst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HCl and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  9. Method for the production of hydrocarbons using iron-carbon-based catalysts

    SciTech Connect

    Rice, G.W.; Fiato, R.A.; Soled, S.L.

    1988-11-29

    This patent describes a process for producing C/sub 2/+ aliphatic hydrocarbons from a CO and H/sub 2/ mixture comprising the step of contacting the mixture with a catalyst comprising finely divided nonpyrophoric iron-carbon catalyst particles comprising iron and carbon, in the substantial absence of silicon, a substantial portion of which is dementite, which was produced in a reaction zone in the presence of laser radiation under such conditions of laser flux density, power adsorption, concentration of iron compound reactants selected from the group consisting of iron carbonyls, iron acetylacetonate, and ferrocene, and pressure sufficient to produce non-pyrophoric iron-carbon particles having average diameters between 1 and 100 nm.

  10. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... testing. You may use critical-flow gas dividers, capillary-tube gas dividers, or thermal-mass-meter gas... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You...

  11. The Southern Ocean biogeochemical divide

    NASA Astrophysics Data System (ADS)

    Marinov, I.; Gnanadesikan, A.; Toggweiler, J. R.; Sarmiento, J. L.

    2006-06-01

    Modelling studies have demonstrated that the nutrient and carbon cycles in the Southern Ocean play a central role in setting the air-sea balance of CO2 and global biological production. Box model studies first pointed out that an increase in nutrient utilization in the high latitudes results in a strong decrease in the atmospheric carbon dioxide partial pressure (pCO2). This early research led to two important ideas: high latitude regions are more important in determining atmospheric pCO2 than low latitudes, despite their much smaller area, and nutrient utilization and atmospheric pCO2 are tightly linked. Subsequent general circulation model simulations show that the Southern Ocean is the most important high latitude region in controlling pre-industrial atmospheric CO2 because it serves as a lid to a larger volume of the deep ocean. Other studies point out the crucial role of the Southern Ocean in the uptake and storage of anthropogenic carbon dioxide and in controlling global biological production. Here we probe the system to determine whether certain regions of the Southern Ocean are more critical than others for air-sea CO2 balance and the biological export production, by increasing surface nutrient drawdown in an ocean general circulation model. We demonstrate that atmospheric CO2 and global biological export production are controlled by different regions of the Southern Ocean. The air-sea balance of carbon dioxide is controlled mainly by the biological pump and circulation in the Antarctic deep-water formation region, whereas global export production is controlled mainly by the biological pump and circulation in the Subantarctic intermediate and mode water formation region. The existence of this biogeochemical divide separating the Antarctic from the Subantarctic suggests that it may be possible for climate change or human intervention to modify one of these without greatly altering the other.

  12. The Southern Ocean biogeochemical divide.

    PubMed

    Marinov, I; Gnanadesikan, A; Toggweiler, J R; Sarmiento, J L

    2006-06-22

    Modelling studies have demonstrated that the nutrient and carbon cycles in the Southern Ocean play a central role in setting the air-sea balance of CO(2) and global biological production. Box model studies first pointed out that an increase in nutrient utilization in the high latitudes results in a strong decrease in the atmospheric carbon dioxide partial pressure (pCO2). This early research led to two important ideas: high latitude regions are more important in determining atmospheric pCO2 than low latitudes, despite their much smaller area, and nutrient utilization and atmospheric pCO2 are tightly linked. Subsequent general circulation model simulations show that the Southern Ocean is the most important high latitude region in controlling pre-industrial atmospheric CO(2) because it serves as a lid to a larger volume of the deep ocean. Other studies point out the crucial role of the Southern Ocean in the uptake and storage of anthropogenic carbon dioxide and in controlling global biological production. Here we probe the system to determine whether certain regions of the Southern Ocean are more critical than others for air-sea CO(2) balance and the biological export production, by increasing surface nutrient drawdown in an ocean general circulation model. We demonstrate that atmospheric CO(2) and global biological export production are controlled by different regions of the Southern Ocean. The air-sea balance of carbon dioxide is controlled mainly by the biological pump and circulation in the Antarctic deep-water formation region, whereas global export production is controlled mainly by the biological pump and circulation in the Subantarctic intermediate and mode water formation region. The existence of this biogeochemical divide separating the Antarctic from the Subantarctic suggests that it may be possible for climate change or human intervention to modify one of these without greatly altering the other.

  13. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Gas divider. 1065.248 Section 1065.248... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You may use a gas divider to blend calibration gases. (b) Component requirements. Use a gas divider...

  14. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Gas divider. 1065.248 Section 1065.248... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You may use a gas divider to blend calibration gases. (b) Component requirements. Use a gas divider...

  15. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Gas divider. 1065.248 Section 1065.248... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You may use a gas divider to blend calibration gases. (b) Component requirements. Use a gas divider...

  16. 40 CFR 1065.248 - Gas divider.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Gas divider. 1065.248 Section 1065.248... PROCEDURES Measurement Instruments Flow-Related Measurements § 1065.248 Gas divider. (a) Application. You may use a gas divider to blend calibration gases. (b) Component requirements. Use a gas divider...

  17. Applications of Neutron Scattering in the Chemical Industry: Proton Dynamics of Highly Dispersed Materials, Characterization of Fuel Cell Catalysts, and Catalysts from Large-Scale Chemical Processes

    NASA Astrophysics Data System (ADS)

    Albers, Peter W.; Parker, Stewart F.

    The attractiveness of neutron scattering techniques for the detailed characterization of materials of high degrees of dispersity and structural complexity as encountered in the chemical industry is discussed. Neutron scattering picks up where other analytical methods leave off because of the physico-chemical properties of finely divided products and materials whose absorption behavior toward electromagnetic radiation and electrical conductivity causes serious problems. This is demonstrated by presenting typical applications from large-scale production technology and industrial catalysis. These include the determination of the proton-related surface chemistry of advanced materials that are used as reinforcing fillers in the manufacture of tires, where interrelations between surface chemistry, rheological properties, improved safety, and significant reduction of fuel consumption are the focus of recent developments. Neutron scattering allows surface science studies of the dissociative adsorption of hydrogen on nanodispersed, supported precious metal particles of fuel cell catalysts under in situ loading at realistic gas pressures of about 1 bar. Insight into the occupation of catalytically relevant surface sites provides valuable information about the catalyst in the working state and supplies essential scientific input for tailoring better catalysts by technologists. The impact of deactivation phenomena on industrial catalysts by coke deposition, chemical transformation of carbonaceous deposits, and other processes in catalytic hydrogenation processes that result in significant shortening of the time of useful operation in large-scale plants can often be traced back in detail to surface or bulk properties of catalysts or materials of catalytic relevance. A better understanding of avoidable or unavoidable aspects of catalyst deactivation phenomena under certain in-process conditions and the development of effective means for reducing deactivation leads to more energy

  18. Photo-oxidation catalysts

    DOEpatents

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

    2009-07-14

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

  19. Structural studies of hydrodesulfurization catalysts

    SciTech Connect

    Sanchez, A.

    1983-01-01

    Hydrodesulfurization (HDS) is a catalytic process used to remove sulfur from S-containing compounds by converting it to hdyrogen sulfide in the presence of dihydrogen. Catalysts used in HDS are mainly made of molybdenum and cobalt sulfides supported on ..gamma..-alumina. The objective of this work was to correlate changes in the HDS activity of these catalysts with structural information obtained by X-ray absorption spectroscopy (XAS). Two series of catalysts were prepared, one by incipient wetness impregnation and the other by bulk impregnation. The catalysts had approximately the same Mo content and varying Co content, and were tested for thiophene HDS in a fixed bed reactor at 573 K and atmospheric pressure. Extended X-ray absorption fine structure (EXAFS) and X-ray absorption edge spectroscopy (XAES) were used at the Mo and Co K-edges. The catalysts were treated in a mixture of hydrogen sulfide/dihydrogen. For both series of catalysts, HDS activity increased with atomic ratio r = Co/(Co + Mo), reached a maximum and declined with further increase in r. Catalysts prepared by incipient wetness impregnation showed higher HDS activity. From EXAFS and XAES, it appears that molybdenum has a local environment similar to that of molybdenum disulfide, very dispersed on the surface of the alumina. Cobalt has sulfur atoms as nearest neighbors. The number N(S) of sulfur neighbors of Mo, determined from EXAFS, depends on r like HDS activity, and shows a linear correlation with HDS activity that holds for both series of catalysts. It seems reasonable that as r increases, the sulfur binding energy of Mo increases until the maximum value of N(S) is reached, and then declines.

  20. Synthesis of iron based hydrocracking catalysts

    DOEpatents

    Farcasiu, Malvina; Eldredge, Patricia A.; Ladner, Edward P.

    1993-01-01

    A method of preparing a fine particle iron based hydrocracking catalyst and the catalyst prepared thereby. An iron (III) oxide powder and elemental sulfur are reacted with a liquid hydrogen donor having a hydroaromatic structure present in the range of from about 5 to about 50 times the weight of iron (III) oxide at a temperature in the range of from about 180.degree. C. to about 240.degree. C. for a time in the range of from about 0 to about 8 hours. Various specific hydrogen donors are disclosed. The catalysts are active at low temperature (<350.degree. C.) and low pressure.

  1. The Myth about the Digital Divide

    ERIC Educational Resources Information Center

    Hawkins, Brian L.; Oblinge, Diana G.

    2006-01-01

    Although computer ownership is not 100 percent, progress has been made on closing the digital divide. However, defining the digital divide according to the haves and have-nots of computer ownership is only a starting point. Beyond computer ownership, colleges and universities should explore the "second-level digital divide," which can be caused by…

  2. Tech, Teachers & Teens: Bridging the Divide

    ERIC Educational Resources Information Center

    Stuht, Amy Colcord; Colcord, Cean

    2011-01-01

    In past decades, the "digital divide" referred to the gap between those who could afford access to technology and those who could not. The divide has shifted in recent years to reflect the growing technological chasm between teachers and their students: today's schools and teenagers' worlds. The digital divide is widening and deepening…

  3. Comparing Internet and Mobile Phone Digital Divides.

    ERIC Educational Resources Information Center

    Rice, Ronald E.; Katz, James E.

    2002-01-01

    Discussion of the digital divide focuses on the Internet and mobile phone digital divide. Analyses of a telephone survey from 2000 considers similarities and differences in three kinds of digital dividers for both the Internet and the mobile phone: users and nonusers, users and dropouts, and recent and veteran users. (Author/LRW)

  4. Diversity, Disability, and Geographic Digital Divide

    ERIC Educational Resources Information Center

    Sumari, Melati; Carr, Erika; Ndebe-Ngovo, Manjerngie

    2006-01-01

    The phenomenon called digital divide was the focus of this paper. Diversity, disability, and geographical digital divide were relevant to this collaborative project. An extensive review of the literature was conducted for the completion of this project. The evidence for the digital divide in terms of race, level of education, and gender in the…

  5. Power Divider for Waveforms Rich in Harmonics

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III

    2005-01-01

    A method for dividing the power of an electronic signal rich in harmonics involves the use of an improved divider topology. A divider designed with this topology could be used, for example, to propagate a square-wave signal in an amplifier designed with a push-pull configuration to enable the generation of more power than could be generated in another configuration.

  6. Catalyst activator

    DOEpatents

    McAdon, Mark H.; Nickias, Peter N.; Marks, Tobin J.; Schwartz, David J.

    2001-01-01

    A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

  7. Phosphine-Free EWG-Activated Ruthenium Olefin Metathesis Catalysts

    NASA Astrophysics Data System (ADS)

    Grela, Karol; Szadkowska, Anna; Michrowska, Anna; Bieniek, Michal; Sashuk, Volodymyr

    Hoveyda-Grubbs catalyst has been successfully fine-tuned by us in order to increase its activity and applicability by the introduction of electron-withdrawing groups (EWGs) to diminish donor properties of the oxygen atom. As a result, the stable and easily accessible nitro-substituted Hoveyda-Grubbs catalyst has found a number of successful applications in various research and industrial laboratories. Some other EWG-activated Hoveyda-type catalysts are commercially available. The results described herewith demonstrate that the activity of ruthenium (Ru) metathesis catalysts can be enhanced by introduction of EWGs without detriment to catalysts stability. Equally noteworthy is the observation that different Ru catalysts turned out to be optimal for different applications. This shows that no single catalyst outperforms all others in all possible applications.

  8. Social Welfare Implications of the Digital Divide

    ERIC Educational Resources Information Center

    Kim, Eunjin; Lee, Byungtae; Menon, Nirup M.

    2009-01-01

    The Internet plays a critical role in informing individuals about society, politics, business, and the environment. So much so that it has been said that the digital divide makes the segment of society on the ''right side'' of the divide (the digitally endowed group) better off and that on the ''wrong side'' (the digitally challenged group) worse…

  9. Bridge the Digital Divide for Educational Equity

    ERIC Educational Resources Information Center

    Mason, Christine Y.; Dodds, Richard

    2005-01-01

    Students' technological savvy has challenged schools to make greater use of computers and the Internet in their curricula, but unfortunately, not every student has the same access to it, and the inability to keep pace has created a digital divide that continues to widen. The digital divide particularly affects students who are black, Hispanic,…

  10. Fundamental Limitations Of Passive Power Dividers

    NASA Technical Reports Server (NTRS)

    Antsos, Dimitrios

    1995-01-01

    Report presents novel theoretical analysis of performance of passive, multiport power dividers like those used to distribute power to radiating elements of array antennas. Typically, unit cell of power-divider network is three- or four-port subnetwork with one port terminated, and subnetworks of network cascaded in multiple layers, so that insertion losses are of major concern.

  11. Parochial Geographies: Growing up in Divided Belfast

    ERIC Educational Resources Information Center

    Leonard, Madeleine

    2010-01-01

    This article explores the ways in which teenagers occupy and manage space in one divided community in Northern Ireland. Drawing on stories, maps and focus group discussions with 80 teenagers, from an interface area in Belfast, the article reveals their perceptions and experiences of divided cities, as risky landscapes. Teenagers respond to these…

  12. Fine motor control

    MedlinePlus

    ... out the child's developmental age. Children develop fine motor skills over time, by practicing and being taught. To have fine motor control, children need: Awareness and planning Coordination Muscle ...

  13. An ultra wideband Wilkinson power divider

    NASA Astrophysics Data System (ADS)

    Hazeri, Ali Reza

    2012-04-01

    In this article, an ultra wideband power divider is proposed, analysed and designed. The design approach of the proposed power divider is derived from even/odd mode analysis. The design approach is validated, and the power divider is simulated by two full-wave electromagnetic simulators (ADS and Sonnet) and fabricated on a substrate with a thickness of 0.635 mm and relative constant of 10.2. Measured results of the proposed power divider show equal power split, excellent insertion loss and good return loss at all the three ports, and a good isolation between the two output ports is achieved over the specified 3.1-10.6 GHz ultra wideband range. In the input port return loss, there are two transmission poles around 5.2 and 9.5 GHz. The overall size of the proposed power divider is just ? .

  14. Fluidized reduction of oxides on fine metal powders without sintering

    NASA Technical Reports Server (NTRS)

    Hayashi, T.

    1985-01-01

    In the process of reducing extremely fine metal particles (av. particle size or = 1000 angstroms) covered with an oxide layer, the metal particles are fluidized by a gas flow contg. H, heated, and reduced. The method uniformly and easily reduces surface oxide layers of the extremely fine metal particles without causing sintering. The metal particles are useful for magnetic recording materials, conductive paste, powder metallurgy materials, chem. reagents, and catalysts.

  15. [Catalyst research]. Final Report

    SciTech Connect

    Ian P Rothwell; David R McMillin

    2005-03-14

    Research results are the areas of catalyst precursor synthesis, catalyst fluxionality, catalyst stability, polymerization of {alpha}-olefins as well as the chemistry of Group IV and Group V metal centers with aryloxide and arylsulfide ligands.

  16. Centrosome positioning in non-dividing cells.

    PubMed

    Barker, Amy R; McIntosh, Kate V; Dawe, Helen R

    2016-07-01

    Centrioles and centrosomes are found in almost all eukaryotic cells, where they are important for organising the microtubule cytoskeleton in both dividing and non-dividing cells. The spatial location of centrioles and centrosomes is tightly controlled and, in non-dividing cells, plays an important part in cell migration, ciliogenesis and immune cell functions. Here, we examine some of the ways that centrosomes are connected to other organelles and how this impacts on cilium formation, cell migration and immune cell function in metazoan cells.

  17. STUDY OF SOLVENT AND CATALYST INTERACTIONS IN DIRECT COAL LIQUEFACTION

    SciTech Connect

    Michael T. Klein

    1998-10-01

    Major objectives of the present project are to develop a better understanding of the roles of the catalyst and the liquefaction solvent in the coal liquefaction process. An open question concerning the role of the catalyst is whether intimate contact between the catalyst and the coal particles is important or required. To answer this question, it had been planned to coat an active catalyst with a porous silica coating which was found to retain catalyst activity while preventing actual contact between catalyst and coal. Consultation with people in DuPont who coat catalysts for increasing abrasion resistance have indicated that only portions of the catalyst are coated by their process (spray drying) and that sections of uncoated catalyst remain. For that reason, it was decided to suspend the catalyst in a basket separated from the coal in the reactor. The basket walls were to be permeable to the liquefaction solvent but not to the coal particles. Several such baskets were constructed of stainless steel with holes which would not permit passage of coal particles larger than 30 mesh. Liquefactions run with the coal of greater than 30 mesh size gave normal conversion of coal to liquid in the absence of catalyst in the basket, but substantially increased conversion when Ni/Mo on alumina catalyst was in the basket. While this result is interesting and suggestive of some kind of mass transfer of soluble material occurring between the catalyst and the coal, it does not eliminate the possibility of breakdown of the coal particle into particle sizes permeable to the basket. Indeed, a small amount of fine coal has been found inside the basket. To determine whether fine coal from breakdown of the coal particles is responsible for the conversion, a new basket is being prepared with 0.5{micro}m pore size.

  18. Fundamental studies of hydrogen interaction with supported meta and bimetallic catalysts

    SciTech Connect

    Bhatia, S.

    1993-12-07

    The thesis is divided into 3 parts: interaction of H with silica supported Ru catalysts (high pressure in situ NMR), in situ NMR study of H interaction with supported Ru-group IB bimetallic catalysts, and in-situ NMR study of H effects on silica-supported Pt, Rh and Ru catalysts.

  19. Development of Novel Supported Gold Catalysts: A Materials Perspective

    SciTech Connect

    Dai, Sheng; Ma, Zhen

    2011-01-01

    Since Haruta et al. discovered that small gold nanoparticles finely dispersed on certain metal oxide supports can exhibit surprisingly high activity in CO oxidation below room temperature, heterogeneous catalysis by supported gold nanoparticles has attracted tremendous attention. The majority of publications deal with the preparation and characterization of conventional gold catalysts (e.g., Au/TiO{sub 2}), the use of gold catalysts in various catalytic reactions, as well as elucidation of the nature of the active sites and reaction mechanisms. In this overview, we highlight the development of novel supported gold catalysts from a materials perspective. Examples, mostly from those reported by our group, are given concerning the development of simple gold catalysts with single metal-support interfaces and heterostructured gold catalysts with complicated interfacial structures. Catalysts in the first category include active Au/SiO{sub 2} and Au/metal phosphate catalysts, and those in the second category include catalysts prepared by pre-modification of supports before loading gold, by post-modification of supported gold catalysts, or by simultaneous dispersion of gold and an inorganic component onto a support. CO oxidation has generally been employed as a probe reaction to screen the activities of these catalysts. These novel gold catalysts not only provide possibilities for applied catalysis, but also furnish grounds for fundamental research.

  20. Wideband unbalanced waveguide power dividers and combiners

    DOEpatents

    Halligan, Matthew; McDonald, Jacob Jeremiah; Strassner, II, Bernd H.

    2016-05-17

    The various technologies presented herein relate to waveguide dividers and waveguide combiners for application in radar systems, wireless communications, etc. Waveguide dividers-combiners can be manufactured in accordance with custom dimensions, as well as in accordance with waveguide standards such that the input and output ports are of a defined dimension and have a common impedance. Various embodiments are presented which can incorporate one or more septum(s), one or more pairs of septums, an iris, an input matching region, a notch located on the input waveguide arm, waveguide arms having stepped transformer regions, etc. The various divider configurations presented herein can be utilized in high fractional bandwidth applications, e.g., a fractional bandwidth of about 30%, and RF applications in the Ka frequency band (e.g., 26.5-40 GHz).

  1. Characterization of Fine Powders

    NASA Astrophysics Data System (ADS)

    Krantz, Matthew; Zhang, Hui; Zhu, Jesse

    Fine powders are used in many applications and across many industries such as powdered paints and pigments, ceramics, petrochemicals, plastics, pharmaceuticals, and bulk and fine chemicals, to name a few. In addition, fine powders must often be handled as a waste by-product, such as ash generated in combustion and gasification processes. In order to correctly design a process and process equipment for application and handling of powders, especially fine powders, it is essential to understand how the powder would behave. Many characterization techniques are available for determining the flow properties of powders; however, care must be taken in selecting the most appropriate technique(s).

  2. WIDE BAND REGENERATIVE FREQUENCY DIVIDER AND MULTIPLIER

    DOEpatents

    Laine, E.F.

    1959-11-17

    A regenerative frequency divider and multiplier having wide band input characteristics is presented. The circuit produces output oscillations having frequencies related by a fixed ratio to input oscillations over a wide band of frequencies. In accomplishing this end, the divider-multiplier includes a wide band input circuit coupled by mixer means to a wide band output circuit having a pass band related by a fixed ratio to that of the input circuit. A regenerative feedback circuit derives a fixed frequency ratio feedback signal from the output circuit and applies same to the mixer means in proper phase relation to sustain fixed frequency ratio oscillations in the output circuit.

  3. Divide and shape: an endosymbiont in action.

    PubMed

    Pyke, Kevin A

    2013-02-01

    The endosymbiotic evolution of the plastid within the host cell required development of a mechanism for efficient division of the plastid. Whilst a model for the mechanism of chloroplast division has been constructed, little is known of how other types of plastids divide, especially the proplastid, the progenitor of all plastid types in the cell. It has become clear that plastid shape is highly heterogeneous and dynamic, especially stromules. This article considers how such variation in morphology might be controlled and how such plastids might divide efficiently.

  4. Electrochemical catalyst recovery method

    DOEpatents

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

    A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.

  5. Electrochemical catalyst recovery method

    DOEpatents

    Silva, L.J.; Bray, L.A.

    1995-05-30

    A method of recovering catalyst material from latent catalyst material solids includes: (a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; (b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; (c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and (d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications. 3 figs.

  6. Long-Life Catalyst

    NASA Technical Reports Server (NTRS)

    1999-01-01

    STC Catalysts, Inc. (SCi) manufactures a noble metal reducible oxide catalyst consisting primarily of platinum and tin dioxide deposited on a ceramic substrate. It is an ambient temperature oxidation catalyst that was developed primarily for Carbon Dioxide Lasers.The catalyst was developed by the NASA Langley Research Center for the Laser Atmospheric Wind Sounder Program (LAWS) which was intended to measure wind velocity on a global basis. There are a number of NASA owned patents covering various aspects of the catalyst.

  7. From Digital Divide to Digital Democracy.

    ERIC Educational Resources Information Center

    de los Santos, Gerardo E., Ed.; de los Santos, Alfredo G., Jr., Ed.; Milliron, Mark David, Ed.

    This publication is one of many efforts of the League for Innovation in the Community College to address the issue of societal technology access and learning needs. This work addresses the issue of the digital divide, which includes the often conflicting perspectives of information technology (IT) access and literacy needs held by government…

  8. Young People's Internet Use: Divided or Diversified?

    ERIC Educational Resources Information Center

    Boonaert, Tom; Vettenburg, Nicole

    2011-01-01

    This article critically analyses research on young people's internet use. Based on a literature analysis, it examines which young people do what on the internet. These results invite a reflection on the dominant discourse on the digital divide. Within this discourse, there is a strong focus on the use of the internet for information purposes only,…

  9. Project DIVIDE Instrument Development. Technical Report # 0810

    ERIC Educational Resources Information Center

    Ketterlin-Geller, Leanne; Jung, Eunju; Geller, Josh; Yovanoff, Paul

    2008-01-01

    In this technical report, we describe the development of cognitive diagnostic test items that form the basis of the diagnostic system for Project DIVIDE (Dynamic Instruction Via Individually Designed Environments). The construct underlying the diagnostic test is division of fractions. We include a description of the process we used to identify the…

  10. THE DEVELOPMENT OF THE TEACHING SPACE DIVIDER.

    ERIC Educational Resources Information Center

    BELLOMY, CLEON C.; CAUDILL, WILLIAM W.

    TYPES OF VERTICAL WORK SURFACES AND THE DEVELOPMENT OF A MODEL TEACHING SPACE DIVIDER ARE DISCUSSED IN THIS REPORT. THIS DESIGN IS BASED ON THE EXPRESSED NEED FOR MORE TACKBOARD AND SHELVING SPACE, AND FOR MOVABLE PARTITIONS. THE MODEL PANELS WHICH SERVE DIRECTLY AS PARTITIONS RATHER THAN BEING OVERLAID ON A PLASTERED SURFACE, INCLUDE THE…

  11. An automatic bridge for inductive voltage dividers

    SciTech Connect

    Chang, P.; Liang, C.P.; Hsiao, J.C.

    1994-12-31

    We describe an automatic, injection-type bridge for inductive voltage divider (IVD) applications at low audio frequencies. We used it to self-calibrate programmable IVDs fabricated in house, by an automated {open_quotes}boot-strap{close_quotes} procedure. It is the heart of our reference standard for ac voltage ratios as well as a calibration system for IVDs.

  12. Leveraging Resources to Close the Divide

    ERIC Educational Resources Information Center

    Rourke, James R.

    2007-01-01

    A host of real and perceived chasms divide students who achieve high academic standards and those who fail to meet them: varying expectations, economic status, resources, cultural and racial preconceptions, inappropriate standards, and so on. Yet as with all human endeavors throughout history, inventors, innovators, and risk takers rise to the…

  13. Dividing Fractions: What Is the Divisor's Role?

    ERIC Educational Resources Information Center

    Coughlin, Heather A.

    2010-01-01

    Dividing by fractions is considered by many to be one of the most complicated procedures in elementary mathematics. The computations are not only complicated but also challenging to explain in the context of a word problem. In this article, the author discusses the role of the divisor in the concept of division by fractions. She examines three…

  14. Pt-Ni and Pt-Co Catalyst Synthesis Route for Fuel Cell Applications

    NASA Technical Reports Server (NTRS)

    Firdosy, Samad A.; Ravi, Vilupanur A.; Valdez, Thomas I.; Kisor, Adam; Narayan, Sri R.

    2013-01-01

    Oxygen reduction reactions (ORRs) at the cathode are the rate-limiting step in fuel cell performance. The ORR is 100 times slower than the corresponding hydrogen oxidation at the anode. Speeding up the reaction at the cathode will improve fuel cell efficiency. The cathode material is generally Pt powder painted onto a substrate (e.g., graphite paper). Recent efforts in the fuel cell area have focused on replacing Pt with Pt-X alloys (where X = Co, Ni, Zr, etc.) in order to (a) reduce cost, and (b) increase ORR rates. One of these strategies is to increase ORR rates by reducing the powder size, which would result in an increase in the surface area, thereby facilitating faster reaction rates. In this work, a process has been developed that creates Pt-Ni or Pt-Co alloys that are finely divided (on the nano scale) and provide equivalent performance at lower Pt loadings. Lower Pt loadings will translate to lower cost. Precursor salts of the metals are dissolved in water and mixed. Next, the salt mixtures are dried on a hot plate. Finally, the dried salt mixture is heattreated in a furnace under flowing reducing gas. The catalyst powder is then used to fabricate a membrane electrode assembly (MEA) for electrochemical performance testing. The Pt- Co catalyst-based MEA showed comparable performance to an MEA fabri cated using a standard Pt black fuel cell catalyst. The main objective of this program has been to increase the overall efficiencies of fuel cell systems to support power for manned lunar bases. This work may also have an impact on terrestrial programs, possibly to support the effort to develop a carbon-free energy source. This catalyst can be used to fabricate high-efficiency fuel cell units that can be used in space as regenerative fuel cell systems, and terrestrially as primary fuel cells. Terrestrially, this technology will become increasingly important when transition to a hydrogen economy occurs.

  15. The Digital Divide: A Global View

    NASA Astrophysics Data System (ADS)

    Ntoko, Alexander

    2011-04-01

    Huge progress was made in bridging the digital divide in first decade of 21^st century. This was largely due to the explosive growth of mobile, which saw numbers rise from under 500 million to over five billion mobile cellular subscriptions in just ten years. With household mobile penetration rates of over 50% even in rural areas of developing countries, we have achieved the dream of bringing all the world's people within reach of communications technology. We must now, however, replicate the mobile miracle for the Internet, and especially broadband, if we are to avoid creating a new broadband breach to replace the digital divide. Three things need to happen for this to be achieved: firstly, broadband needs to be brought to the top of the development agenda; secondly, broadband needs to become much more affordable and thirdly, security needs to be part of the strategy.

  16. Will the Nicaragua Canal connect or divide?

    PubMed

    Gross, Michael

    2014-11-01

    A century after the opening of the Panama Canal, a second inter-oceanic passage is set to be built in Central America, this time in Nicaragua. The ambitious and astronomically expensive project promises to bring economic opportunity to a poor country but it also carries risks to its tropical ecosystems. Will the new waterway ultimately link two oceans or divide a continent? Michael Gross investigates.

  17. Can Attention be Divided Between Perceptual Groups?

    NASA Technical Reports Server (NTRS)

    McCann, Robert S.; Foyle, David C.; Johnston, James C.; Hart, Sandra G. (Technical Monitor)

    1994-01-01

    Previous work using Head-Up Displays (HUDs) suggests that the visual system parses the HUD and the outside world into distinct perceptual groups, with attention deployed sequentially to first one group and then the other. New experiments show that both groups can be processed in parallel in a divided attention search task, even though subjects have just processed a stimulus in one perceptual group or the other. Implications for models of visual attention will be discussed.

  18. Lake Buchannan, Great Dividing Range, Queensland, Australia

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Lake Buchannan, a small but blue and prominent in the center of the view, lies in the Great Dividing of Queensland, Australia (22.0S, 146.0E). The mountain range in this case is a low plateau of no more than 2,000 to 3,000 ft altitude. The interior is dry, mostly in pasture but the coastal zone in contrast, is wet tropical country where bananas and sugarcane are grown.

  19. Will the Nicaragua Canal connect or divide?

    PubMed

    Gross, Michael

    2014-11-01

    A century after the opening of the Panama Canal, a second inter-oceanic passage is set to be built in Central America, this time in Nicaragua. The ambitious and astronomically expensive project promises to bring economic opportunity to a poor country but it also carries risks to its tropical ecosystems. Will the new waterway ultimately link two oceans or divide a continent? Michael Gross investigates. PMID:25587585

  20. Catalytic conversion of lignocellulosic biomass to fine chemicals and fuels.

    PubMed

    Zhou, Chun-Hui; Xia, Xi; Lin, Chun-Xiang; Tong, Dong-Shen; Beltramini, Jorge

    2011-11-01

    Lignocellulosic biomass is the most abundant and bio-renewable resource with great potential for sustainable production of chemicals and fuels. This critical review provides insights into the state-of the-art accomplishments in the chemocatalytic technologies to generate fuels and value-added chemicals from lignocellulosic biomass, with an emphasis on its major component, cellulose. Catalytic hydrolysis, solvolysis, liquefaction, pyrolysis, gasification, hydrogenolysis and hydrogenation are the major processes presently studied. Regarding catalytic hydrolysis, the acid catalysts cover inorganic or organic acids and various solid acids such as sulfonated carbon, zeolites, heteropolyacids and oxides. Liquefaction and fast pyrolysis of cellulose are primarily conducted over catalysts with proper acidity/basicity. Gasification is typically conducted over supported noble metal catalysts. Reaction conditions, solvents and catalysts are the prime factors that affect the yield and composition of the target products. Most of processes yield a complex mixture, leading to problematic upgrading and separation. An emerging technique is to integrate hydrolysis, liquefaction or pyrolysis with hydrogenation over multifunctional solid catalysts to convert lignocellulosic biomass to value-added fine chemicals and bio-hydrocarbon fuels. And the promising catalysts might be supported transition metal catalysts and zeolite-related materials. There still exist technological barriers that need to be overcome (229 references). PMID:21863197

  1. Catalytic conversion of lignocellulosic biomass to fine chemicals and fuels.

    PubMed

    Zhou, Chun-Hui; Xia, Xi; Lin, Chun-Xiang; Tong, Dong-Shen; Beltramini, Jorge

    2011-11-01

    Lignocellulosic biomass is the most abundant and bio-renewable resource with great potential for sustainable production of chemicals and fuels. This critical review provides insights into the state-of the-art accomplishments in the chemocatalytic technologies to generate fuels and value-added chemicals from lignocellulosic biomass, with an emphasis on its major component, cellulose. Catalytic hydrolysis, solvolysis, liquefaction, pyrolysis, gasification, hydrogenolysis and hydrogenation are the major processes presently studied. Regarding catalytic hydrolysis, the acid catalysts cover inorganic or organic acids and various solid acids such as sulfonated carbon, zeolites, heteropolyacids and oxides. Liquefaction and fast pyrolysis of cellulose are primarily conducted over catalysts with proper acidity/basicity. Gasification is typically conducted over supported noble metal catalysts. Reaction conditions, solvents and catalysts are the prime factors that affect the yield and composition of the target products. Most of processes yield a complex mixture, leading to problematic upgrading and separation. An emerging technique is to integrate hydrolysis, liquefaction or pyrolysis with hydrogenation over multifunctional solid catalysts to convert lignocellulosic biomass to value-added fine chemicals and bio-hydrocarbon fuels. And the promising catalysts might be supported transition metal catalysts and zeolite-related materials. There still exist technological barriers that need to be overcome (229 references).

  2. Firn Structure Evolution at WAIS Divide

    NASA Astrophysics Data System (ADS)

    Harwell, E. N.; Albert, M. R.; Gregory, S.; Keegan, K. M.

    2013-12-01

    The polar ice sheets serve as natural archives of past climate, as well as sensitive indicators of current climate change. The physical structure of snow and firn is sensitive to local environmental changes. The top 60-120 m of wide expanses of the Greenland and Antarctic ice sheets consists of firn, snow that is more than a year old. This porous structure serves as a natural archive of past atmospheric composition and plays an important role in the initiation of the ice core record of past atmospheres, and also plays a key role in remote sensing. This paper examines the physical nature of firn at the WAIS Divide ice core site in West Antarctica. Measurements of the density and permeability profiles are reported from the surface over the depth of the firn column profile. The WAIS Divide ice core site was chosen to be the Antarctic analog of the high-resolution GISP2 core from Summit, Greenland; both sites are cold sites with high accumulation rates. We describe similarities and differences in the structure of firn by comparing measurements from WAIS Divide and Summit, and we identify causes for differences.

  3. Splicing the Divide: A Review of Research on the Evolving Digital Divide among K-12 Students

    ERIC Educational Resources Information Center

    Dolan, Jennifer E.

    2016-01-01

    The digital divide has narrowed with regard to one definition of access to technology--the binary view of the "haves" and "have-nots." However, use of technology at home and in school is not equitable for all students. According to recent literature, a broader and more nuanced definition of the technological divide is necessary…

  4. Nano-catalysts: Key to the Greener Pathways Leading to Sustainability

    EPA Science Inventory

    Synthetic processes using alternative energy input in combination with nano-catalysts shorten the reaction time that eliminate or minimize side product formation. This concept is already finding acceptance in the syntheses of pharmaceuticals, fine chemicals, and polymers and may ...

  5. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction

    SciTech Connect

    Song, Chunshan; Schobert, H.H.

    1993-02-01

    Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on the development of novel bimetallic dispersed catalysts for temperature-programmed liquefaction. The ultimate goal of the present research is to develop novel catalytic hydroliquefaction process using highly active dispersed catalysts. The primary objective of this research is to develop novel bimetallic dispersed catalysts from organometallic molecular that can be used in low precursors concentrations (< 1 %) but exhibit high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. The major technical approaches are, first, to prepare the desired heteronuclear organometallic molecules as catalyst precursors that contain covalently bound, two different metal atoms and sulfur in a single molecule. Such precursors will generate finely dispersed bimetallic catalysts such as Fe-Mo, Co-Mo and Ni-Mo binary sulfides upon thermal decomposition. The second major technical approach is to perform the liquefaction of coals unpregnated with the organometallic precursors under temperature-programmed conditions, where the programmed heat-up serves as a step for both catalyst activation and coal pretreatment or preconversion. Two to three different complexes for each of the Fe-Mo, Co-Mo, and Ni-Mo combinations will be prepared. Initial catalyst screening tests will be conducted using a subbituminous coal and a bituminous coal. Effects of coal rank and solvents will be examined with the selected bimetallic catalysts which showed much higher activity than the dispersed catalysts from conventional precursors.

  6. Fine particle pollution

    Atmospheric Science Data Center

    2013-01-10

    ...   Satellites Track Human Exposure to Fine Particle Pollution   St. Louis, Missouri Alaskan Wildfires ... provides a good test region for satellite observations of pollution. ( Full St. Louis article ) MISR ...

  7. Analyses of fine paste ceramics

    SciTech Connect

    Sabloff, J A

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

  8. Attrition Resistant Fischer-Tropsch Catalysts Based on FCC Supports

    SciTech Connect

    Adeyiga, Adeyinka

    2010-02-05

    Commercial spent fluid catalytic cracking (FCC) catalysts provided by Engelhard and Albemarle were used as supports for Fe-based catalysts with the goal of improving the attrition resistance of typical F-T catalysts. Catalysts with the Ruhrchemie composition (100 Fe/5 Cu/4.2 K/25 spent FCC on mass basis) were prepared by wet impregnation. XRD and XANES analysis showed the presence of Fe{sub 2}O{sub 3} in calcined catalysts. FeC{sub x} and Fe{sub 3}O{sub 4} were present in the activated catalysts. The metal composition of the catalysts was analyzed by ICP-MS. F-T activity of the catalysts activated in situ in CO at the same conditions as used prior to the attrition tests was measured using a fixed bed reactor at T = 573 K, P = 1.38 MPa and H{sub 2}:CO ratio of 0.67. Cu and K promoted Fe supported over Engelhard provided spent FCC catalyst shows relatively good attrition resistance (8.2 wt% fines lost), high CO conversion (81%) and C{sub 5}+ hydrocarbons selectivity (18.3%).

  9. Preferential solvation: dividing surface vs excess numbers.

    PubMed

    Shimizu, Seishi; Matubayasi, Nobuyuki

    2014-04-10

    How do osmolytes affect the conformation and configuration of supramolecular assembly, such as ion channel opening and actin polymerization? The key to the answer lies in the excess solvation numbers of water and osmolyte molecules; these numbers are determinable solely from experimental data, as guaranteed by the phase rule, as we show through the exact solution theory of Kirkwood and Buff (KB). The osmotic stress technique (OST), in contrast, purposes to yield alternative hydration numbers through the use of the dividing surface borrowed from the adsorption theory. However, we show (i) OST is equivalent, when it becomes exact, to the crowding effect in which the osmolyte exclusion dominates over hydration; (ii) crowding is not the universal driving force of the osmolyte effect (e.g., actin polymerization); (iii) the dividing surface for solvation is useful only for crowding, unlike in the adsorption theory which necessitates its use due to the phase rule. KB thus clarifies the true meaning and limitations of the older perspectives on preferential solvation (such as solvent binding models, crowding, and OST), and enables excess number determination without any further assumptions. PMID:24689966

  10. Preferential solvation: dividing surface vs excess numbers.

    PubMed

    Shimizu, Seishi; Matubayasi, Nobuyuki

    2014-04-10

    How do osmolytes affect the conformation and configuration of supramolecular assembly, such as ion channel opening and actin polymerization? The key to the answer lies in the excess solvation numbers of water and osmolyte molecules; these numbers are determinable solely from experimental data, as guaranteed by the phase rule, as we show through the exact solution theory of Kirkwood and Buff (KB). The osmotic stress technique (OST), in contrast, purposes to yield alternative hydration numbers through the use of the dividing surface borrowed from the adsorption theory. However, we show (i) OST is equivalent, when it becomes exact, to the crowding effect in which the osmolyte exclusion dominates over hydration; (ii) crowding is not the universal driving force of the osmolyte effect (e.g., actin polymerization); (iii) the dividing surface for solvation is useful only for crowding, unlike in the adsorption theory which necessitates its use due to the phase rule. KB thus clarifies the true meaning and limitations of the older perspectives on preferential solvation (such as solvent binding models, crowding, and OST), and enables excess number determination without any further assumptions.

  11. Modern multiphase catalysis: new developments in the separation of homogeneous catalysts.

    PubMed

    Muldoon, Mark J

    2010-01-14

    Homogeneous catalysts are powerful tools for the synthesis of fine chemicals, pharmaceuticals and materials, however their exploitation on an industrial scale is often held back due to the challenges of separating and recycling the catalyst. This perspective focuses on approaches to multiphase catalysis that have emerged in the last decade, highlighting methods that can address the separation issues and in some cases result in superior catalyst performance and environmental benefits.

  12. Characterization of three-way automotive catalysts

    SciTech Connect

    Kenik, E.A.; More, K.L.; LaBarge, W.

    1997-04-01

    The CRADA between Delphi Automotive Systems (Delphi; formerly General Motors - AC Delco, Systems) and Lockheed Martin Energy Research (LMER) on automotive catalysts was completed at the end of FY96, after a ten month, no-cost extension. The CRADA was aimed at improved performance and lifetime of noble metal based three-way-catalysts (TWC), which are the primary catalytic system for automotive emission control systems. While these TWC can meet the currently required emission standards, higher than optimum noble metal loadings are often required to meet lifetime requirements. In addition, more stringent emission standards will be imposed in the near future, demanding improved performance and service life from these catalysts. Understanding the changes of TWC conversion efficiency with ageing is a critical need in improving these catalysts. Initially in a fresh catalyst, the active material is often distributed on a very fine scale, approaching single atoms or small atomic clusters. As such, a wide range of analytical techniques have been employed to provide high spatial resolution characterization of the evolving state of the catalytic material.

  13. Catalyst by Design

    SciTech Connect

    Narula, Chaitanya Kumar; DeBusk, Melanie Moses

    2014-01-01

    The development of new catalytic materials is still dominated by trial and error methods. Although it has been successful, the empirical development of catalytic materials is time consuming and expensive with no guarantee of success. In our laboratories, we are developing a comprehensive catalysts by design that involves state-of-the-art first principle density functional theory calculations, experimental design of catalyst sites, and sub- ngstr m resolution imaging with an aberration-corrected electron microscope to characterize the microstructure. In this chapter, we focus on supported platinum cluster catalyst systems which are one of the most important industrial catalysts and attempt to demonstrate the feasibility of the catalyst by design concept.

  14. Library outreach: addressing Utah's "Digital Divide".

    PubMed

    McCloskey, K M

    2000-10-01

    A "Digital Divide" in information and technological literacy exists in Utah between small hospitals and clinics in rural areas and the larger health care institutions in the major urban area of the state. The goals of the outreach program of the Spencer S. Eccles Health Sciences Library at the University of Utah address solutions to this disparity in partnership with the National Network of Libraries of Medicine-- Midcontinental Region, the Utah Department of Health, and the Utah Area Health Education Centers. In a circuit-rider approach, an outreach librarian offers classes and demonstrations throughout the state that teach information-access skills to health professionals. Provision of traditional library services to unaffiliated health professionals is integrated into the library's daily workload as a component of the outreach program. The paper describes the history, methodology, administration, funding, impact, and results of the program.

  15. Overview of catalyst testing and coprocessing studies at Sandia National Laboratories

    SciTech Connect

    Stohl, F.V.; Goodnow, D.C.; Diegert, K.V.; Andujar, L.

    1997-10-01

    Prior to the initiation of Sandia`s fine particle size catalyst testing project, it was not feasible to compare the activities of the many direct coal liquefaction catalysts developed in various laboratories. This was due to the wide variety of testing methods used by the different catalyst developers. Sandia developed a procedure that uses a bituminous coal (DECS-17 Blind Canyon coal), phenathrene as the reaction solvent, and a factorial experimental design with three variables: temperature, time, and catalyst loading. Numerous catalysts have been evaluated. Pacific Northwest National Laboratories` (PNNL) 6-line ferrihydrite catalyst is the most active among the particulate catalysts. West Virginia University`s (WVU) iron catalyst impregnated on Blind Canyon coal is the best iron catalyst evaluated to date. Because this catalyst was prepared by impregnation, which involves several preparation steps, it cannot be directly compared to particulate catalysts. In an effort to enable this comparison, WVU produced a particulate iron catalyst that has been tested at Sandia. In addition, Sandia has also evaluated several of Argonne National Laboratory`s molybdenum and iron catalysts that were impregnated on Wyodak subbituminous coal from the Argonne Premium Coal Sample Program. Current activities are focused on developing capabilities for performing coprocessing experiments to support FETC`s coprocessing thrust and a new project aimed at helping Puerto Rico solve its waste disposal problems.

  16. System for reactivating catalysts

    DOEpatents

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  17. Catalyst patterning for nanowire devices

    NASA Technical Reports Server (NTRS)

    Li, Jun (Inventor); Cassell, Alan M. (Inventor); Han, Jie (Inventor)

    2004-01-01

    Nanowire devices may be provided that are based on carbon nanotubes or single-crystal semiconductor nanowires. The nanowire devices may be formed on a substrate. Catalyst sites may be formed on the substrate. The catalyst sites may be formed using lithography, thin metal layers that form individual catalyst sites when heated, collapsible porous catalyst-filled microscopic spheres, microscopic spheres that serve as masks for catalyst deposition, electrochemical deposition techniques, and catalyst inks. Nanowires may be grown from the catalyst sites.

  18. Catalytic upgrading of butyric acid towards fine chemicals and biofuels

    PubMed Central

    Sjöblom, Magnus; Matsakas, Leonidas; Christakopoulos, Paul; Rova, Ulrika

    2016-01-01

    Fermentation-based production of butyric acid is robust and efficient. Modern catalytic technologies make it possible to convert butyric acid to important fine chemicals and biofuels. Here, current chemocatalytic and biocatalytic conversion methods are reviewed with a focus on upgrading butyric acid to 1-butanol or butyl-butyrate. Supported Ruthenium- and Platinum-based catalyst and lipase exhibit important activities which can pave the way for more sustainable process concepts for the production of green fuels and chemicals. PMID:26994015

  19. Textured catalysts and methods of making textured catalysts

    DOEpatents

    Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.

    2007-03-06

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  20. Quantitative Measurement of the Digital Divide

    NASA Astrophysics Data System (ADS)

    Cottrell, Roger

    2007-04-01

    Bandwidth and the Internet infrastructure are the life-blood of the world's knowledge economy, but they are often scarcest where most needed. Measuring the numbers of users of the Internet infrastructure is not easy in developing countries because many people share accounts, use corporate and academic networks, or visit the rapidly growing number of cyber cafes, telecentres and business services. Also measuring the number of users does not take into account the level of use. One valuable indicator for measuring the Internet infrastructure is the international Internet performance of a country or region. One of the major aims of the PingER project is to provide an historical archive of extensive, publicly accessible, up-to-date, measurements, analyses and reports of multiple Internet performance indicators (such as delay, loss, throughput, reachability, and jitter) between sites, countries and regions of the world. This talk will briefly describe the PingER project and then compare and contrast the Internet performance and its trends within and between countries and regions of the world. By means of extensive case studies it will also identify which regions need the greatest attention, together with their major issues and possible approaches to reducing the divide.

  1. Bridging the divide between science and journalism.

    PubMed

    Van Eperen, Laura; Marincola, Francesco M; Strohm, Jennifer

    2010-03-10

    There are countless reasons nearly every scientist should learn how to communicate effectively with the media, including increased understanding of critical research findings to attract or sustain funding and build new professional partnerships that will further propel forward research. But where do scientists begin? Bridging the Divide between Science and Journalism offers practical tips for any scientist looking to work with the media.Given the traditional and internet-based sources for medical research and healthcare-related news now available, it is imperative that scientists know how to communicate their latest findings through the appropriate channels. The credible media channels are managed by working journalists, so learning how to package vast, technical research in a form that is appetizing and "bite-sized" in order to get their attention, is an art. Reducing years of research into a headline can be extremely difficult and certainly doesn't come naturally to every scientist, so this article provides suggestions on how to work with the media to communicate your findings.

  2. Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

    PubMed Central

    Bagheri, Samira; Muhd Julkapli, Nurhidayatullaili; Bee Abd Hamid, Sharifah

    2014-01-01

    The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO2) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO2 supported metal catalysts have attracted interest due to TiO2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO2 as a support material for heterogeneous catalysts and its potential applications. PMID:25383380

  3. Fine-tuning silencing.

    PubMed

    Panning, Barbara

    2010-01-01

    Polycomb Repressive Complex 2 (PRC2) modifies chromatin to silence many embryonic patterning genes, restricting their expression to the appropriate cell populations. Two reports in Cell by Peng et al. (2009) and Shen et al. (2009) identify Jarid2/Jumonji, a new component of PRC2, which inhibits PRC2 enzymatic activity to fine-tune silencing.

  4. Methods of making textured catalysts

    DOEpatents

    Werpy, Todd; Frye, Jr., John G.; Wang, Yong; Zacher, Alan H.

    2010-08-17

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  5. Catalyst Alloys Processing

    NASA Astrophysics Data System (ADS)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  6. Catalyst enhances Claus operations

    SciTech Connect

    Dupin, T.; Voizin, R.

    1982-11-01

    An improved Claus catalyst offers superior activity that emphasizes hydrolysis of CS/sub 2/ in the first converter. The catalyst is insensitive to oxygen action at concentrations generally found in Claus gas feeds. It also has an excellent resistance to hydrothermal shocks that may occur during shutdown of the sulfur line. Collectively, these properties make this catalyst the most active formula now available for optimum Claus yields and COS/CS/sub 2/ hydrolysis conversion.

  7. Polyolefin catalyst manufacturing

    SciTech Connect

    Inkrott, K.E.; Scinta, J.; Smith, P.D. )

    1989-10-16

    Statistical process control (SPC) procedures are absolutely essential for making new-generation polyolefin catalysts with the consistent high quality required by modern polyolefin processes. Stringent quality assurance is critical to the production of today's high-performance catalysts. Research and development efforts during the last 20 years have led to major technological improvements in the polyolefin industry. New generation catalysts, which once were laboratory curiosities, must now be produced commercially on a regular and consistent basis to meet the increasing requirements of the plastics manufacturing industry. To illustrate the more stringent requirements for producing the new generation polyolefin catalysts, the authors compare the relatively simple, first-generation polypropylene catalyst production requirements with some of the basic requirements of manufacturing a more complex new-generation catalyst, such as Catalyst Resources Inc.'s LYNX 900. The principles which hold true for the new-generation catalysts such as LYNX 900 are shown to apply equally to the scale-up of other advanced technology polyolefin catalysts.

  8. Liquefaction with microencapsulated catalysts

    DOEpatents

    Weller, Sol W.

    1985-01-01

    A method of dispersing a liquefaction catalyst within coal or other carbonaceous solids involves providing a suspension in oil of microcapsules containing the catalyst. An aqueous solution of a catalytic metal salt is emulsified in the water-immiscible oil and the resulting minute droplets microencapsulated in polymeric shells by interfacial polycondensation. The catalyst is subsequently blended and dispersed throughout the powdered carbonaceous material to be liquefied. At liquefaction temperatures the polymeric microcapsules are destroyed and the catalyst converted to minute crystallites in intimate contact with the carbonaceous material.

  9. Fine Arts and Humanities: Grade 7. Cluster III.

    ERIC Educational Resources Information Center

    Calhoun, Olivia H.

    A curriculum guide for Grade 7, the document is devoted to the occupational cluster "Fine Arts and Humanities." It is divided into five units: drama and literature, music, dance, art, and crafts. Each unit is introduced by a statement of the topic, the unit's purpose, main ideas, quests, and a list of career opportunities (positions)available in…

  10. Fine particle separation apparatus

    SciTech Connect

    Berriman, L.P.; Paul, D.G.

    1981-07-21

    An apparatus is claimed for separating almost all fine particles, including particles less than 10 microns in diameter, from a gas stream, which requires the input of only a small amount of water and which discharges a correspondingly small amount of particle-water slurry. The apparatus includes a vertical cylindrical chamber having a relatively wide upstream portion that gradually narrows in a transition portion into an elongated throat portion. A central core member extends axially along the throat portion and forms an elongated annular passage. A high velocity gas stream containing fine particles is generally tangentially introduced into the wide upstream portion of the conduit to provide a circulatory flow. Water is introduced through a plurality of parts in the transition portion downstream therefrom, to provide a thin layer of water along the outer walls of the throat. The high velocity circulatory flow of the particle-laden gas along the annular throat region causes fine particles to migrate radially outwardly under high centrifugal forces into the water layer. The water-particle slurry is discharged through a slot in the outer wall of the lower portion of the throat region. The substantially particle-free gas passes through a radial diffuser section therebelow.

  11. NMR sensor for onboard ship detection of catalytic fines in marine fuel oils.

    PubMed

    Sørensen, Morten K; Vinding, Mads S; Bakharev, Oleg N; Nesgaard, Tomas; Jensen, Ole; Nielsen, Niels Chr

    2014-08-01

    A mobile, low-field nuclear magnetic resonance (NMR) sensor for onboard, inline detection of catalytic fines in fuel oil in the shipping industry is presented as an alternative to onshore laboratory measurements. Catalytic fines (called cat fines) are aluminosilicate zeolite catalysts utilized in the oil cracking process at refineries. When present in fuel oil, cat fines cause abrasive wear of engine parts and may ultimately lead to engine breakdown with large economical consequences, thereby motivating methods for inline measurements. Here, we report on a robust, mobile, and low-cost (27)Al NMR sensor for continuous online measurement of the level of catalytic fines in fuel oil onboard ships. The sensor enables accurate measurements of aluminum (catalytic fines) in ppm concentrations in good agreement with commercial laboratory reference measurements.

  12. NMR sensor for onboard ship detection of catalytic fines in marine fuel oils.

    PubMed

    Sørensen, Morten K; Vinding, Mads S; Bakharev, Oleg N; Nesgaard, Tomas; Jensen, Ole; Nielsen, Niels Chr

    2014-08-01

    A mobile, low-field nuclear magnetic resonance (NMR) sensor for onboard, inline detection of catalytic fines in fuel oil in the shipping industry is presented as an alternative to onshore laboratory measurements. Catalytic fines (called cat fines) are aluminosilicate zeolite catalysts utilized in the oil cracking process at refineries. When present in fuel oil, cat fines cause abrasive wear of engine parts and may ultimately lead to engine breakdown with large economical consequences, thereby motivating methods for inline measurements. Here, we report on a robust, mobile, and low-cost (27)Al NMR sensor for continuous online measurement of the level of catalytic fines in fuel oil onboard ships. The sensor enables accurate measurements of aluminum (catalytic fines) in ppm concentrations in good agreement with commercial laboratory reference measurements. PMID:24988044

  13. Fischer-Tropsch Catalysts

    NASA Technical Reports Server (NTRS)

    White, James H. (Inventor); Taylor, Jesse W. (Inventor)

    2008-01-01

    Catalyst compositions and methods for F-T synthesis which exhibit high CO conversion with minor levels (preferably less than 35% and more preferably less than 5%) or no measurable carbon dioxide generation. F-T active catalysts are prepared by reduction of certain oxygen deficient mixed metal oxides.

  14. Reducible oxide based catalysts

    DOEpatents

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

    2010-04-06

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

  15. Nanostructured catalyst supports

    SciTech Connect

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2015-09-29

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  16. Improved zeolitic isocracking catalysts

    SciTech Connect

    Dahlberg, A.J.; Habib, M.M.; Moore, R.O.; Law, D.V.; Convery, L.J.

    1995-09-01

    Chevron Research Company introduced the first low pressure, low temperature catalytic hydrocracking process--ISOCRACKING--in 1959. Within the last four years, Chevron has developed and commercialized three new zeolitic ISOCRACKING catalysts. ICR 209 is Chevron`s latest noble metal ISOCRACKING catalyst. It offers improved liquid yield stability, longer life, and superior polynuclear aromatics control compared to its predecessor. ICR 209`s high hydrogenation activity generates the highest yields of superior quality jet fuel of any zeolitic ISOCRACKING catalyst. The second new ISOCRACKING catalyst, ICR 208, is a base metal catalyst which combines high liquid selectivity and high light naphtha octane in hydrocrackers operating for maximum naphtha production. ICR 210 is another new base metal catalyst which offers higher liquid yields and longer life than ICR 208 by virtue of a higher hydrogenation-to-acidity ratio. Both ICR 208 and ICR 210 have been formulated to provide higher liquid yield throughout the cycle and longer cycle length than conventional base metal/zeolite catalysts. This paper will discuss the pilot plant and commercial performances of these new ISOCRACKING catalysts.

  17. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2012-10-02

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  18. ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

    SciTech Connect

    K. Jothimurugesan; James G. Goodwin, Jr.; Santosh K. Gangwal

    1999-10-01

    Fischer-Tropsch (FT) synthesis to convert syngas (CO + H{sub 2}) derived from natural gas or coal to liquid fuels and wax is a well-established technology. For low H{sub 2} to CO ratio syngas produced from CO{sub 2} reforming of natural gas or from gasification of coal, the use of Fe catalysts is attractive because of their high water gas shift activity in addition to their high FT activity. Fe catalysts are also attractive due to their low cost and low methane selectivity. Because of the highly exothermic nature of the FT reaction, there has been a recent move away from fixed-bed reactors toward the development of slurry bubble column reactors (SBCRs) that employ 30 to 90 {micro}m catalyst particles suspended in a waxy liquid for efficient heat removal. However, the use of FeFT catalysts in an SBCR has been problematic due to severe catalyst attrition resulting in fines that plug the filter employed to separate the catalyst from the waxy product. Fe catalysts can undergo attrition in SBCRs not only due to vigorous movement and collisions but also due to phase changes that occur during activation and reaction.

  19. Improved catalysts and method

    SciTech Connect

    Taylor, C.E.; Noceti, R.P.

    1990-12-31

    An improved catalyst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HCl and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride. 8 figs., 3 tabs.

  20. Bismuth - modified supported catalysts

    SciTech Connect

    Nadirov, N.K.; Lykova, L.F.; Petrosyan, L.S.

    1985-09-01

    Bismuth was used as an additive to three-component catalysts prepared through modification of an aluminoplatinorhenium catalyst by III and IV nontransition and iron subgroup elements. Since there is conflicting information on bismuth additions, the role of bismuth in polycomponent catalysts and whether it promotes aromatization catalysts was considered. The effect of temperature on the yield of n-hexane conversion products in the presence of Pt-Re-Co-Bi/gamma-A1/sub 2/O/sub 3/ is shown. Conclusive results establish that the addition of 0.5% nickel to a 0.3 Pt-0.3 Re/gamma-A1/sub 2/O/sub 3/ catalyst (in wt.%) increased the yield of benzene from n-hexane by 5.7%. It was also shown that 0.1 to 0.25 wt.% bismuth poisons two- and three-component samples containing 0.25 to 0.3 wt.% platinum.

  1. Exploring Careers in Fine Arts and Humanities: A Guide for Teachers.

    ERIC Educational Resources Information Center

    Kennedy, Elsie

    One of 11 guides designed for junior high school teachers who wish to develop their own materials related to the fine arts and humanities area of career education, the primary focus is on identifying the components within each segment of the arts and humanities and the career areas within each segment. The fine arts are divided into art, music,…

  2. Coordination and Fine Motor Control Depends on Drosophila TRPγ

    PubMed Central

    Akitake, Bradley; Ren, Qiuting; Boiko, Nina; Ni, Jinfei; Sokabe, Takaaki; Stockand, James D.; Eaton, Benjamin A.; Montell, Craig

    2015-01-01

    Motor coordination is broadly divided into gross and fine motor control, both of which depend on proprioceptive organs. However, the channels that function specifically in fine motor control are unknown. Here, we show that mutations in trpγ disrupt fine motor control while leaving gross motor proficiency intact. The mutants are unable to coordinate precise leg movements during walking, and are ineffective in traversing large gaps due to an inability in making subtle postural adaptations that are requisite for this task. TRPγ is expressed in proprioceptive organs, and is required in both neurons and glia for gap crossing. We expressed TRPγ in vitro, and found that its activity is promoted by membrane stretch. A mutation eliminating the Na+/Ca2+ exchanger suppresses the gap crossing phenotype of trpγ flies. Our findings indicate that TRPγ contributes to fine motor control through mechanical activation in proprioceptive organs, thereby promoting Ca2+ influx, which is required for function. PMID:26028119

  3. Very fine Twilights

    NASA Astrophysics Data System (ADS)

    Boico, Vladimir

    1992-04-01

    The author is describing a very fine twilight on 3 January 1992 at 17 h25 m LT (The Sunset was at 16h48m LT) of red - terracotta color. The author is relating this twilight with the volcanic erruption of Pinatubo on the Philipines islands from June 1991. The author is describing the following phenomena related with Volcanic erruption: twilights, the greenish of the Moon's surface, a change in the color of Day Sky to white, Haloes around the Sun. The author is pointing out, that the phenomena mentioned could prolonge in time 2 or 3 years.

  4. Fine needle aspiration cytology.

    PubMed Central

    Lever, J V; Trott, P A; Webb, A J

    1985-01-01

    Fine needle aspiration cytology is an inexpensive, atraumatic technique for the diagnosis of disease sites. This paper describes the technique and illustrates how it may be applied to the management of tumours throughout the body. The limitations of the method, the dangers of false positive reports, and the inevitability of false negative diagnoses are emphasised. In a clinical context the method has much to offer by saving patients from inappropriate operations and investigations and allowing surgeons to plan quickly and more rationally. It is an economically valuable technique and deserves greater recognition. Images PMID:2578481

  5. Fine Channel Networks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A color image of fine channel networks on Mars; north toward top. The scene shows heavily cratered highlands dissected by dendritic open channel networks that dissect steep slopes of impact crater walls. This image is a composite of Viking high-resolution images in black and white and low-resolution images in color. The image extends from latitude 9 degrees S. to 5 degrees S. and from longitude 312 degrees to 320 degrees; Mercator projection. The dendritic pattern of the fine channels and their location on steep slopes leads to the interpretation that these are runoff channels. The restriction of these types of channels to ancient highland rocks suggests that these channels are old and date from a time on Mars when conditions existed for precipitation to actively erode rocks. After the channels reach a low plain, they appear to end. Termination may have resulted from burial by younger deposits or perhaps the flows percolated into the surface materials and continued underground.

  6. Synthesis and Properties of Magnetic Fine Particles

    NASA Astrophysics Data System (ADS)

    Tang, Zhongxun

    Magnetic fine particles with a variety of compositions and sizes have been prepared by aerosol and coprecipitation technique. Their magnetic properties are shown to be either similar to or quite different from those of their bulk counterparts. Iron oxide, barium iron oxide and neodynium iron based fine particles have been synthesized by an aerosol technique which produced particles with average size of about 100 nm. It was found that the as-received samples were usually in thermally unstable states because of their short residence time (seconds) at the high temperature when they were created. Heat treatment turned these as -received particles into more stable phases. The final product depended on temperature, environment and composition of the initial solution. Cation and anion effects and solvent effects on the formation and morphology of the final particle have been also observed. Manganese ferrite fine particles have been made by hydroxide induced coprecipitation of mixed iron and manganese salt solutions. The particle size appeared to be an unique function of the ratio of the metallic ion concentration to the hydroxide ion concentration when the digestion conditions were fixed. The system which used ferric salt created small MnFe_2 O_4 particles with size controllable between 5 and 25 nm. The digestion process could be described by an Ostwald ripening in which OH^- acts as a catalyst. Variation of cations showed that their oxidation states had a strong influence on the particle size. The system which used ferrous salt, however, produced larger ferrite particles (above 50 nm) with single ferrite phase (Mn_ xFe_{3-x}O_4 with x <= 0.7). Dissolution and renucleation/growth occurred during digestion. For larger particles, the magnetizations were the same as for the bulk of the phases present, while the coercivities were more system dependent. We have found that nanoscale particles, on the other hand, showed profound size effects. The saturation magnetization of

  7. Increasing FCC regenerator catalyst level

    SciTech Connect

    Wong, R.F. )

    1993-11-01

    A Peruvian FCC unit's operations were improved by increasing the regenerator's catalyst level. This increase resulted in lower stack losses, an improved temperature profile, increased catalyst activity and a lower catalyst consumption rate. A more stable operation saved this Peruvian refiner over $131,000 per year in catalyst alone. These concepts and data may be suitable for your FCC unit as well.

  8. Intercalated clay catalysts

    SciTech Connect

    Pinnavaia, T.J.

    1983-04-22

    Recent advances in the intercalation of metal complex cations in smectite clay minerals are leading to the development of new classes of selective heterogeneous catalysts. The selectivity of both metal-catalyzed and proton-catalyzed chemical conversions in clay intercalates can often be regulated by controlling surface chemical equilibria, interlamellar swelling, or reactant pair proximity in the interlayer regions. Also, the intercalation of polynuclear hydroxy metal cations and metal cluster cations in smectites affords new pillared clay catalysts with pore sizes that can be made larger than those of conventional zeolite catalysts.

  9. Intercalated Clay Catalysts

    NASA Astrophysics Data System (ADS)

    Pinnavaia, Thomas J.

    1983-04-01

    Recent advances in the intercalation of metal complex cations in smectite clay minerals are leading to the development of new classes of selective heterogeneous catalysts. The selectivity of both metal-catalyzed and proton-catalyzed chemical conversions in clay intercalates can often be regulated by controlling surface chemical equilibria, interlamellar swelling, or reactant pair proximity in the interlayer regions. Also, the intercalation of polynuclear hydroxy metal cations and metal cluster cations in smectites affords new pillared clay catalysts with pore sizes that can be made larger than those of conventional zeolite catalysts.

  10. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2011-11-15

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  11. Catalyst for microelectromechanical systems microreactors

    DOEpatents

    Morse, Jeffrey D.; Sopchak, David A.; Upadhye, Ravindra S.; Reynolds, John G.; Satcher, Joseph H.; Gash, Alex E.

    2010-06-29

    A microreactor comprising a silicon wafer, a multiplicity of microchannels in the silicon wafer, and a catalyst coating the microchannels. In one embodiment the catalyst coating the microchannels comprises a nanostructured material. In another embodiment the catalyst coating the microchannels comprises an aerogel. In another embodiment the catalyst coating the microchannels comprises a solgel. In another embodiment the catalyst coating the microchannels comprises carbon nanotubes.

  12. Deactivation by carbon of iron catalysts for indirect liquefaction

    SciTech Connect

    Bartholomew, C.H.

    1991-01-10

    Although promoted cobalt and iron catalysts for Fischer-Tropsch (FT) synthesis of gasoline feedstock were first developed more than three decades ago, a major technical problem still limiting the commercial use of these catalysts today is carbon deactivation. This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for FT synthesis, the objectives of which are to: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; and model the rates of deactivation of the same catalysts in fixed-bed reactors. To accomplish the above objectives, the project is divided into the following tasks: (1) determine the kinetics of reaction and of carbon deactivation during CO hydrogenation on Fe and Fe/K catalysts coated on monolith bodies. (2) Determine the reactivities and types of carbon deposited during reaction on the same catalysts from temperature-programmed-surface-reaction spectroscopy (TPSR) and transmission electron microscopy (TEM). Determine the types of iron carbides formed at various temperatures and H{sub 2}/CO ratios using x-ray diffraction and Moessbauer spectroscopy. (3) Develop mathematical deactivation models which include heat and mass transport contributions for FT synthesis is packed-bed reactors. Progress to date is described. 48 refs., 3 figs., 1 tab.

  13. Catalysts and method

    DOEpatents

    Taylor, Charles E.; Noceti, Richard P.

    1991-01-01

    An improved catlayst and method for the oxyhydrochlorination of methane is disclosed. The catalyst includes a pyrogenic porous support on which is layered as active material, cobalt chloride in major proportion, and minor proportions of an alkali metal chloride and of a rare earth chloride. On contact of the catalyst with a gas flow of methane, HC1 and oxygen, more than 60% of the methane is converted and of that converted more than 40% occurs as monochloromethane. Advantageously, the monochloromethane can be used to produce gasoline boiling range hydrocarbons with the recycle of HCl for further reaction. This catalyst is also of value for the production of formic acid as are analogous catalysts with lead, silver or nickel chlorides substituted for the cobalt chloride.

  14. Epoxidation catalyst and process

    DOEpatents

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  15. Granulation of fine powder

    DOEpatents

    Chen, Ching-Fong

    2016-08-09

    A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to form a dense compact with a higher density and more uniform pore size distribution.

  16. Plasmatron-catalyst system

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander; Alexeev, Nikolai

    2004-09-21

    A plasmatron-catalyst system. The system generates hydrogen-rich gas and comprises a plasmatron and at least one catalyst for receiving an output from the plasmatron to produce hydrogen-rich gas. In a preferred embodiment, the plasmatron receives as an input air, fuel and water/steam for use in the reforming process. The system increases the hydrogen yield and decreases the amount of carbon monoxide.

  17. Plasmatron-catalyst system

    DOEpatents

    Bromberg, Leslie; Cohn, Daniel R.; Rabinovich, Alexander; Alexeev, Nikolai

    2007-10-09

    A plasmatron-catalyst system. The system generates hydrogen-rich gas and comprises a plasmatron and at least one catalyst for receiving an output from the plasmatron to produce hydrogen-rich gas. In a preferred embodiment, the plasmatron receives as an input air, fuel and water/steam for use in the reforming process. The system increases the hydrogen yield and decreases the amount of carbon monoxide.

  18. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, Rayford G.; Dosch, Robert G.

    1993-01-01

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  19. Crystalline titanate catalyst supports

    DOEpatents

    Anthony, R.G.; Dosch, R.G.

    1993-01-05

    A series of new crystalline titanates (CT) are shown to have considerable potential as catalyst supports. For Pd supported catalyst, the catalytic activity for pyrene hydrogenation was substantially different depending on the type of CT, and one was substantially more active than Pd on hydrous titanium oxide (HTO). For 1-hexene hydrogenation the activities of the new CTs were approximately the same as for the hydrous metal oxide supports.

  20. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, Robert J.; Gao, Hanrong

    1998-08-04

    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.

  1. Catalyst system comprising a first catalyst system tethered to a supported catalyst

    DOEpatents

    Angelici, R.J.; Gao, H.

    1998-08-04

    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.

  2. Comprehensive catalyst management

    SciTech Connect

    Pritchard, S.

    2007-05-15

    From January 2009, as SCR season expands from five months to year-round to meet new US Clean Air Interstate Rule standards, new catalyst strategies are increasingly important. Power plants will need a comprehensive management strategy that accounts for a wide range of old and new issues to achieve peak performance. An optimum plan is necessary for catalyst replacement or addition. SCR systems should be inspected and evaluated at least once a year. Levels of deactivation agents, most often arsenic and calcium oxide, need to match the particular coals used. Tools such as Cormetech's FIELD Guide are available to quantify the effect on catalyst life under various fuel-firing scenarios. Tests should be conducted to evaluate the NH{sub 3}/NOx distribution over time to maximise catalyst performance. The article gives a case study of catalyst management at the Tennessee Valley Authority Allen plant. Recent changes have created new variables to be considered in a catalyst management process, notably the expansion of the operating temperature range, mercury oxidation and SO{sub 3} emission limits. Cormetech has researched these areas. 5 figs., 2 photos.

  3. A study of aluminophosphate supported Ni-Mo catalysts for hydrocracking bitumen

    SciTech Connect

    Smith, K.J.; Lewkowicz, L.; Oballa, M.C.; Krzywicki, A.

    1994-12-31

    H-Oil and LC-Fining processes utilize a combination of thermal and catalytic hydroprocessing reactions to achieve high yields of distillate in upgrading bitumen or heavy oil residua. The processes are based on a well mixed (ebullated bed) reactor from which deactivated catalyst is continuously withdrawn and fresh catalyst is added to maintain yields. Catalyst activity and lifetime are two key factors controlling the economics of these processes. Catalyst deactivation occurs due to the deposition of coke and metals on the catalyst surface. The choice of catalyst is usually a compromise between two extremes: small pore catalyst with low metals capacity but higher activity that deactivates rapidly because of metals deposition and wide pore catalyst that has high metals deposition capacity but lower activity due to low surface area. Recently, aluminophosphate materials with large pores (< 10 nm--1,000 nm) and high surface areas (100--500 m{sup 2}/g) have been reported. The actual pore size distribution and surface area obtained depend on the Al/P ratio, preparation method and the calcination procedure. These materials are also thermally stable. The purpose of the present work was to determine if such materials, as a result of their pore size distribution and surface area, could decrease the rate of catalyst deactivation, increase catalyst activity and provide sufficient pore volume for high capacity of metals deposition during the upgrading of heavy oil residue.

  4. Automated Camera Array Fine Calibration

    NASA Technical Reports Server (NTRS)

    Clouse, Daniel; Padgett, Curtis; Ansar, Adnan; Cheng, Yang

    2008-01-01

    Using aerial imagery, the JPL FineCalibration (JPL FineCal) software automatically tunes a set of existing CAHVOR camera models for an array of cameras. The software finds matching features in the overlap region between images from adjacent cameras, and uses these features to refine the camera models. It is not necessary to take special imagery of a known target and no surveying is required. JPL FineCal was developed for use with an aerial, persistent surveillance platform.

  5. Alumoxane precursors to designer catalysts and catalyst supports: Catalytic oxidation of dichloromethane

    SciTech Connect

    Cook, R.L.; Wong, C.; Harlan, C.J.; Kareiva, A.; Barron, A.R.

    1997-12-31

    Carboxylato-alumoxanes are aluminum-oxygen macromolecules consisting of a boehmite-like core surrounded by a sheath of carboxylate groups. The alumoxanes may be processed like organic polymers yet when fired are readily transformed into ceramic oxides. The alumoxanes can be precisely doped at room temperature in aqueous solution with a range of metal cations to prepare novel catalyst and catalyst support materials. The ease of introduction of multiple cations into the alumina lattice via the alumoxane approach provides a method for fine-tuning catalyst support properties and the fabrication of new catalyst materials themselves. Manganese-doped alumina (Mn-Al{sub 2}O{sub 3}), formed via the doping of an alumoxane with Mn at room temperature, is presented as an example where the alumoxane route provides enhanced catalytic performance over traditional approaches for the low temperature catalytic oxidation of chlorinated hydrocarbons (CHCs). The Mn-Al{sub 2}O{sub 3} formed from the Mn-doped alumoxane is compared with MnO{sub 2}/Al{sub 2}O{sub 3} prepared by the incipient wetness method, and commercial Pt/Al{sub 2}O{sub 3} for the oxidation/destruction of dichloromethane (CH{sub 2}Cl{sub 2}).

  6. Nano Catalysts for Diesel Engine Emission Remediation

    SciTech Connect

    Narula, Chaitanya Kumar; Yang, Xiaofan; Debusk, Melanie Moses; Mullins, David R; Mahurin, Shannon Mark; Wu, Zili

    2012-06-01

    The objective of this project was to develop durable zeolite nanocatalysts with broader operating temperature windows to treat diesel engine emissions to enable diesel engine based equipment and vehicles to meet future regulatory requirements. A second objective was to improve hydrothermal durability of zeolite catalysts to at least 675 C. The results presented in this report show that we have successfully achieved both objectives. Since it is accepted that the first step in NO{sub x} conversion under SCR (selective catalytic reduction) conditions involves NO oxidation to NO{sub 2}, we reasoned that catalyst modification that can enhance NO oxidation at low-temperatures should facilitate NO{sub x} reduction at low temperatures. Considering that Cu-ZSM-5 is a more efficient catalyst than Fe-ZSM-5 at low-temperature, we chose to modify Cu-ZSM-5. It is important to point out that the poor low-temperature efficiency of Fe-ZSM-5 has been shown to be due to selective absorption of NH{sub 3} at low-temperatures rather than poor NO oxidation activity. In view of this, we also reasoned that an increased electron density on copper in Cu-ZSM-5 would inhibit any bonding with NH{sub 3} at low-temperatures. In addition to modified Cu-ZSM-5, we synthesized a series of new heterobimetallic zeolites, by incorporating a secondary metal cation M (Sc{sup 3+}, Fe{sup 3+}, In{sup 3+}, and La{sup 3+}) in Cu exchanged ZSM-5, zeolite-beta, and SSZ-13 zeolites under carefully controlled experimental conditions. Characterization by diffuse-reflectance ultra-violet-visible spectroscopy (UV-Vis), X-ray powder diffraction (XRD), extended X-ray absorption fine structure spectroscopy (EXAFS) and electron paramagnetic resonance spectroscopy (EPR) does not permit conclusive structural determination but supports the proposal that M{sup 3+} has been incorporated in the vicinity of Cu(II). The protocols for degreening catalysts, testing under various operating conditions, and accelerated aging

  7. Magnetic and dendritic catalysts.

    PubMed

    Wang, Dong; Deraedt, Christophe; Ruiz, Jaime; Astruc, Didier

    2015-07-21

    The recovery and reuse of catalysts is a major challenge in the development of sustainable chemical processes. Two methods at the frontier between homogeneous and heterogeneous catalysis have recently emerged for addressing this problem: loading the catalyst onto a dendrimer or onto a magnetic nanoparticle. In this Account, we describe representative examples of these two methods, primarily from our research group, and compare them. We then describe new chemistry that combines the benefits of these two methods of catalysis. Classic dendritic catalysis has involved either attaching the catalyst covalently at the branch termini or within the dendrimer core. We have used chelating pyridyltriazole ligands to insolubilize catalysts at the termini of dendrimers, providing an efficient, recyclable heterogeneous catalysts. With the addition of dendritic unimolecular micelles olefin metathesis reactions catalyzed by commercial Grubbs-type ruthenium-benzylidene complexes in water required unusually low amounts of catalyst. When such dendritic micelles include intradendritic ligands, both the micellar effect and ligand acceleration promote faster catalysis in water. With these types of catalysts, we could carry out azide alkyne cycloaddition ("click") chemistry with only ppm amounts of CuSO4·5H2O and sodium ascorbate under ambient conditions. Alternatively we can attach catalysts to the surface of superparamagnetic iron oxide nanoparticles (SPIONs), essentially magnetite (Fe3O4) or maghemite (γ-Fe2O3), offering the opportunity to recover the catalysts using magnets. Taking advantage of the merits of both of these strategies, we and others have developed a new generation of recyclable catalysts: dendritic magnetically recoverable catalysts. In particular, some of our catalysts with a γ-Fe2O3@SiO2 core and 1,2,3-triazole tethers and loaded with Pd nanoparticles generate strong positive dendritic effects with respect to ligand loading, catalyst loading, catalytic activity and

  8. An Empirical Analysis of the Determinants of International Digital Divide

    NASA Astrophysics Data System (ADS)

    Yun, Liu

    International Digital Divide is an imbalance state of ICT penetration between countries. This paper analyzes the current status and trends of international digital divide, adopts Gompertz technology diffusion model to verify the determinants of ICT penetration level and diffusion rate separately. Finally, China should use "policy levers" to strengthen international trade cooperation, improve the capability of independent innovation, and achieve Chinese goal of bridging digital divide.

  9. Fine-Tuning Corrective Feedback.

    ERIC Educational Resources Information Center

    Han, ZhaoHong

    2001-01-01

    Explores the notion of "fine-tuning" in connection with the corrective feedback process. Describes a longitudinal case study, conducted in the context of Norwegian as a second a language, that shows how fine-tuning and lack thereof in the provision of written corrective feedback differentially affects a second language learner's restructuring of…

  10. Low Temperature Oxidation Catalyst

    NASA Technical Reports Server (NTRS)

    1995-01-01

    One day soon homeowners everywhere may be protected from deadly carbon monoxide fumes, thanks to a device invented at NASA Langley Research Center in Hampton, Va. It uses a new class of low-temperature oxidation catalysts to convert carbon monoxide to non-toxic carbon dioxide at room temperature. It can also remove formaldehyde from the air. The catalysts initially were developed for research involving carbon dioxide lasers. Industry already has shown an interest. Rochester Gas and Electric Co., of Rochester, N.Y., has an agreement with NASA Langley to develop a product for habitable spaces such as homes, cars and aircraft. The Mantic Corp., of Salt Lake City, Utah, plans to use them in breathing apparatus, such as firefighter masks. The catalysts also have applications as trace-gas detectors, and in cold-engine emission control. To work, the catalysts - tin oxide and platinum - are applied to a surface. Air passing over the surface reacts with the catalysts, transforming carbon monoxide and formaldehyde. The device requires no energy for operation, doesn't need to be plugged in, has no moving parts and lasts a long time.

  11. Reforming using erionite catalysts

    SciTech Connect

    Liers, J.; Meusinger, J.; Moesch, A. ); Reschetilowski, W. )

    1993-08-01

    The advantage of reforming on erionite catalysts is a product with high octane numbers and low amounts of aromatics. This advantage seems to be slight at reaction pressures lower than 25 bar. But it is possible to compensate for the influence of pressure by varying the erionite content within the catalyst and the reaction temperature. When reforming on Pt/Al[sub 2]O[sub 3] catalysts, the following reactions take place: dehydrocyclization of paraffins to naphthenes, dehydrogenation of naphthenes to aromatics, isomerication of normal paraffins remains in the product, lowering its octane number. By using a Ni/H-erionite catalyst, the octane rating can be increased by 3 to 7 numbers through selective hydrocracking of n-alkanes in the reformate. Erionite catalysts favor shape-selective hydrocracking of normal paraffins and the formation of cyclopentane derivatives lowering the content of aromatics during reforming reactions. Reducing the reaction pressure decreases hydrocracking activity and cyclopentane formation. These results can be interpreted in terms of thermodynamic restrictions and deactivation.

  12. Chemical composition of Martian fines

    NASA Technical Reports Server (NTRS)

    Clark, B. C.; Baird, A. K.; Weldon, R. J.; Tsusaki, D. M.; Schnabel, L.; Candelaria, M. P.

    1982-01-01

    Of the 21 samples acquired for the Viking X-ray fluorescence spectrometer, 17 were analyzed to high precision. Compared to typical terrestrial continental soils and lunar mare fines, the Martian fines are lower in Al, higher in Fe, and much higher in S and Cl concentrations. Protected fines at the two lander sites are almost indistinguishable, but concentration of the element S is somewhat higher at Utopia. Duricrust fragments, successfully acquired only at the Chryse site, invariably contained about 50% higher S than fines. No elements correlate positively with S, except Cl and possibly Mg. A sympathetic variation is found among the triad Si, Al, Ca; positive correlation occurs between Ti and Fe. Sample variabilities are as great within a few meters as between lander locations (4500 km apart), implying the existence of a universal Martian regolith component of constant average composition. The nature of the source materials for the regolith fines must be mafic to ultramafic.

  13. Quality assurance for purchased catalysts

    SciTech Connect

    Puls, F.H. )

    1988-09-01

    Petrochemical industries require many different types of catalysts in process operations. A significantly portion of these requirements is being met through purchases from merchant catalyst suppliers. The importance of catalysts and of catalyst quality to these industries cannot be overstated. It is not surprising that in the quest for quality which has affected much of US industry in the last few years, catalysts were among the first products which were singled out for development of quality assurance. Currently, catalyst supplier auditing and certification procedures are being implemented. Primary emphasis is on the implementation of statistical process control procedures in the manufacture of commercially available catalyst. Thus, a trend exists to move from quality assurance (QA) and quality control (QC) for purchased catalysts to statistical process control (SPC). This development is being supported by audits of the suppliers' manufacturing quality control systems. The keystone of quality management is the concept of customer and supplier working together for their mutual advantage. The focus in this presentation will be on two topics. (1) Fixed bed catalysts: The recognition of lot-to-lot variations led to purchase specifications which then led to quality control procedures for purchased catalysts. (2) Catalyst suppliers: the limitations of quality control for catalysts will be discussed, and the efforts of catalyst suppliers to apply SPC will be mentioned.

  14. Supported organoiridium catalysts for alkane dehydrogenation

    SciTech Connect

    Baker, R. Thomas; Sattelberger, Alfred P.; Li, Hongbo

    2013-09-03

    Solid supported organoiridium catalysts, a process for preparing such solid supported organoiridium catalysts, and the use of such solid supported organoiridium catalysts in dehydrogenation reactions of alkanes is provided. The catalysts can be easily recovered and recycled.

  15. Rethinking the Digital Divide: Impacts on Student-Tutor Relationships

    ERIC Educational Resources Information Center

    Underwood, Jean D. M.

    2007-01-01

    This article emerged from a series of debates and workshops on the impact of the Digital Divide on educational practice at the "Futures of Learning: New Learning Paradigms Conference" in Paris. The conceptualisation of the Digital Divide into the "haves" and the "have-nots", with a perception of the economically developed world as "high tech" and…

  16. Addressing the Research/Practice Divide in Teacher Education

    ERIC Educational Resources Information Center

    Flessner, Ryan

    2012-01-01

    Educational scholars often describe a research/practice divide. Similarly, students in teacher education programs often struggle to navigate the differences between university coursework and expectations they face in field-based placements. This self-study analyzes one researcher's attempt to address the research/practice divide from the position…

  17. Technology and the Cultural Divide: A Review of the Literature.

    ERIC Educational Resources Information Center

    Grant, Allen C.

    The recent proliferation of technology in educational settings is giving teachers new and innovative methods of teaching an inquiry-based curriculum within a constructivist framework. One problem within the nation's schools is the growing cultural divide. The cultural divide is the extent of the cultural barrier that exists between educators and…

  18. Modified Wilkinson Power Dividers For K And Ka Bands

    NASA Technical Reports Server (NTRS)

    Antsos, Dimitrios

    1995-01-01

    Modified configuration for Wilkinson power dividers devised for operating frequencies in K and Ka bands (18 to 27 and 27 to 40 GHz, respectively). Overcomes some difficulties associated with increasing frequency, making possible to design and accurately predict performances of unequal-split power dividers for frequencies above X-band.

  19. The Digital Divide in Health Education: Myth or Reality?

    ERIC Educational Resources Information Center

    Stellefson, Michael; Chaney, Beth; Chaney, Don

    2008-01-01

    Although e-health interventions provide new opportunities for health education, there has been cause for concern regarding the purported information technology gap between those who have access to digital applications and those who do not--termed the "digital divide." The literature suggests, however, that this divide may now be illusory, driven…

  20. 5 CFR 838.303 - Expressly dividing employee annuity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS (CONTINUED) COURT ORDERS AFFECTING RETIREMENT BENEFITS Requirements for Court Orders Affecting Employee Annuities § 838.303 Expressly dividing employee annuity. (a) A court order directed at employee annuity is not a court order acceptable for processing unless it expressly divides the employee annuity...

  1. 5 CFR 838.303 - Expressly dividing employee annuity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS (CONTINUED) COURT ORDERS AFFECTING RETIREMENT BENEFITS Requirements for Court Orders Affecting Employee Annuities § 838.303 Expressly dividing employee annuity. (a) A court order directed at employee annuity is not a court order acceptable for processing unless it expressly divides the employee annuity...

  2. 5 CFR 838.303 - Expressly dividing employee annuity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS (CONTINUED) COURT ORDERS AFFECTING RETIREMENT BENEFITS Requirements for Court Orders Affecting Employee Annuities § 838.303 Expressly dividing employee annuity. (a) A court order directed at employee annuity is not a court order acceptable for processing unless it expressly divides the employee annuity...

  3. The Digital Divide and Health Outcomes: A Teleretinal Imaging Study

    ERIC Educational Resources Information Center

    Connolly, Kathleen Kihmm

    2013-01-01

    The purpose of this research project was to understand, explore and describe the digital divide and the relationship between technology utilization and health outcomes. Diabetes and diabetic eye disease was used as the real-life context for understanding change and exploring the digital divide. As an investigational framework, a telemedicine…

  4. Connecting across Many Divides: Digital, Racial, and Socio-Economic.

    ERIC Educational Resources Information Center

    Hinson, Janice; Daniel, Cathy

    As Internet usage increases nationally, it becomes more apparent that the Digital Divide (the gap between those who have information access and those who do not) is related to demographics. Although the number of low income and ethnic households that have Internet access is increasing, the Digital Divide is expected to widen because access…

  5. Distance Education and the Digital Divide: An Academic Perspective

    ERIC Educational Resources Information Center

    Block, Judy

    2010-01-01

    This paper will address how the digital divide affects distance education. Lack of access for some students does raise concerns. Access to technology is often defined by what students don't have: what is called a digital divide. Access also is defined by the speed of Internet connections. Access in the future will be even greater as more computers…

  6. Evaluation of Fatih Project in the Frame of Digital Divide

    ERIC Educational Resources Information Center

    Karabacak, Kerim

    2016-01-01

    The aim of this research realized at the general survey model is to evaluate "FATIH Project" in the frame of digital divide by determining the effects of the distributed tablets to the students being educated at K-12 schools on digital divide. Sample is taking from the 9th grade students in Sakarya city in the 2013-2014 academic session.…

  7. Bridging the Digital Divide--An Australian Story

    ERIC Educational Resources Information Center

    Broadbent, Robyn; Papadopoulos, Theo

    2013-01-01

    There is increasing evidence that the lack of access to information and communication technology (ICT) or the "digital divide" severely limits education, employment and economic prospects. This paper reports on the evaluation of a project that aims to bridge the digital divide. In particular, the case study data has been used to bring to life the…

  8. Oxide Nanocrystal Model Catalysts.

    PubMed

    Huang, Weixin

    2016-03-15

    Model catalysts with uniform and well-defined surface structures have been extensively employed to explore structure-property relationships of powder catalysts. Traditional oxide model catalysts are based on oxide single crystals and single crystal thin films, and the surface chemistry and catalysis are studied under ultrahigh-vacuum conditions. However, the acquired fundamental understandings often suffer from the "materials gap" and "pressure gap" when they are extended to the real world of powder catalysts working at atmospheric or higher pressures. Recent advances in colloidal synthesis have realized controlled synthesis of catalytic oxide nanocrystals with uniform and well-defined morphologies. These oxide nanocrystals consist of a novel type of oxide model catalyst whose surface chemistry and catalysis can be studied under the same conditions as working oxide catalysts. In this Account, the emerging concept of oxide nanocrystal model catalysts is demonstrated using our investigations of surface chemistry and catalysis of uniform and well-defined cuprous oxide nanocrystals and ceria nanocrystals. Cu2O cubes enclosed with the {100} crystal planes, Cu2O octahedra enclosed with the {111} crystal planes, and Cu2O rhombic dodecahedra enclosed with the {110} crystal planes exhibit distinct morphology-dependent surface reactivities and catalytic properties that can be well correlated with the surface compositions and structures of exposed crystal planes. Among these types of Cu2O nanocrystals, the octahedra are most reactive and catalytically active due to the presence of coordination-unsaturated (1-fold-coordinated) Cu on the exposed {111} crystal planes. The crystal-plane-controlled surface restructuring and catalytic activity of Cu2O nanocrystals were observed in CO oxidation with excess oxygen. In the propylene oxidation reaction with O2, 1-fold-coordinated Cu on Cu2O(111), 3-fold-coordinated O on Cu2O(110), and 2-fold-coordinated O on Cu2O(100) were identified

  9. Partial oxidation catalyst

    DOEpatents

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

    2000-01-01

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

  10. Catalyst, method of making, and reactions using the catalyst

    DOEpatents

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Gao, Yufei [Kennewick, WA

    2002-08-27

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  11. Catalyst, Method Of Making, And Reactions Using The Catalyst

    DOEpatents

    Tonkovich, Anna Lee Y.; Wang, Yong; Gao, Yufei

    2004-07-13

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  12. Catalyst, method of making, and reactions using the catalyst

    DOEpatents

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Gao, Yufei [Kennewick, WA

    2009-03-03

    The present invention includes a catalyst having a layered structure with, (1) a porous support, (2) a buffer layer, (3) an interfacial layer, and optionally (4) a catalyst layer. The invention also provides a process in which a reactant is converted to a product by passing through a reaction chamber containing the catalyst.

  13. Molecular Engineering of Trifunctional Supported Catalysts for the Aerobic Oxidation of Alcohols.

    PubMed

    Fernandes, Antony E; Riant, Olivier; Jensen, Klavs F; Jonas, Alain M

    2016-09-01

    We describe a simple and general method for the preparation and molecular engineering of supported trifunctional catalysts and their application in the representative Cu/TEMPO/NMI-catalyzed aerobic oxidation of benzyl alcohol. The methodology allows in one single step to immobilize, with precise control of surface composition, both pyta, Cu(I) , TEMPO, and NMI sites on azide-functionalized silica particles. To optimize the performance of the heterogeneous trifunctional catalysts, synergistic interactions are finely engineered through modulating the degree of freedom of the imidazole site as well as tuning the relative surface composition, leading to catalysts with an activity significantly superior to the corresponding homogeneous catalytic system.

  14. Molecular Engineering of Trifunctional Supported Catalysts for the Aerobic Oxidation of Alcohols.

    PubMed

    Fernandes, Antony E; Riant, Olivier; Jensen, Klavs F; Jonas, Alain M

    2016-09-01

    We describe a simple and general method for the preparation and molecular engineering of supported trifunctional catalysts and their application in the representative Cu/TEMPO/NMI-catalyzed aerobic oxidation of benzyl alcohol. The methodology allows in one single step to immobilize, with precise control of surface composition, both pyta, Cu(I) , TEMPO, and NMI sites on azide-functionalized silica particles. To optimize the performance of the heterogeneous trifunctional catalysts, synergistic interactions are finely engineered through modulating the degree of freedom of the imidazole site as well as tuning the relative surface composition, leading to catalysts with an activity significantly superior to the corresponding homogeneous catalytic system. PMID:27430481

  15. Three-dimensional multiway power dividers based on transformation optics.

    PubMed

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  16. Three-dimensional multiway power dividers based on transformation optics

    PubMed Central

    Wu, Yong-Le; Zhuang, Zheng; Deng, Li; Liu, Yuan-An

    2016-01-01

    The two-dimensional (2D) or three-dimensional (3D) multiway power dividers based on transformation optical theory are proposed in this paper. It comprises of several nonisotropic mediums and one isotropic medium without any lumped and distributed elements. By using finite embedded coordinate transformations, the incident beam can be split and bent arbitrarily in order to achieve effective power division and transmission. In addition, the location of the split point can be employed to obtain unequal power dividers. Finally, several typical examples of the generalized power divider without limitation in 3D space are performed, which shows that the proposed power divider can implement required functions with arbitrary power division and arbitrary transmission paths. The excellent simulated results verify the novel design method for power dividers. PMID:27091541

  17. Secret Lives of Catalysts Revealed

    SciTech Connect

    Salmeron, Miquel; Somorjai, Gabor

    2008-01-01

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-releases/2008/10/21/catalysts/

  18. Engelhard expands oxidation catalysts portfolio

    SciTech Connect

    Rotman, D.

    1997-02-26

    Engelhard says its agreement earlier this month to market Amoco Chemical`s proprietary maleic anhydride catalyst reflects an effort to expand its speciality catalysts business (CW, Feb. 19, p.5). In particular, the company says it is looking for additional alliances to bolster its oxidation catalysts portfolio. {open_quotes}There are some areas of oxidation catalysis that are reasonably attractive,{close_quotes} says Paul Lamb, marketing director/chemical catalysts. He says that while Engelhard is not interested in commodity oxidation catalysts, such as those used to make sulfuric acid, it does want to boost offerings for higher-value oxidation catalysts. Engelhard is collaborating with Geon to offer oxychlorination catalysts for making ethylene dichloride. It also markets oxidation catalysts for vinyl acetate production.

  19. Passivating metals on cracking catalysts

    SciTech Connect

    Mckay, D.L.

    1980-01-15

    Metals such as nickel, vanadium and iron contaminating a cracking catalyst are passivated by contacting the cracking catalyst under elevated temperature conditions with antimony selenide, antimony sulfide, antimony sulfate, bismuth selenide, bismuth sulfide, or bismuth phosphate.

  20. Aerogel derived catalysts

    SciTech Connect

    Reynolds, J. G., LLNL

    1996-12-11

    Aerogels area class of colloidal materials which have high surface areas and abundant mesoporous structure. SiO{sub 2} aerogels show unique physical, optical and structural properties. When catalytic metals are incorporated in the aerogel framework, the potential exists for new and very effective catalysts for industrial processes. Three applications of these metal-containing SiO{sub 2} aerogels as catalysts are briefly reviewed in this paper--NO{sub x} reduction, volatile organic compound destruction, and partial oxidation of methane.

  1. Process of making supported catalyst

    DOEpatents

    Schwarz, James A.; Subramanian, Somasundaram

    1992-01-01

    Oxide supported metal catalysts have an additional metal present in intimate association with the metal catalyst to enhance catalytic activity. In a preferred mode, iridium or another Group VIII metal catalyst is supported on a titania, alumina, tungsten oxide, silica, or composite oxide support. Aluminum ions are readsorbed onto the support and catalyst, and reduced during calcination. The aluminum can be added as aluminum nitrate to the iridium impregnate solution, e.g. chloroiridic acid.

  2. 'RAT' Leaves a Fine Mess

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph shows the light signatures, or spectra, of two sides of the rock dubbed 'Bounce,' located at Meridiani Planum, Mars. The spectra were taken by the miniature thermal emission spectrometer on the Mars Exploration Rover Opportunity. The left side of this rock is covered by fine dust created when the rover drilled into the rock with its rock abrasion tool. These 'fines' produce a layer of pyroxene dust that can be detected here in the top spectrum. The right side of the rock has fewer fines and was used to investigate the composition of this basaltic rock.

  3. Uprated fine guidance sensor study

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Future orbital observatories will require star trackers of extremely high precision. These sensors must maintain high pointing accuracy and pointing stability simultaneously with a low light level signal from a guide star. To establish the fine guidance sensing requirements and to evaluate candidate fine guidance sensing concepts, the Space Telescope Optical Telescope Assembly was used as the reference optical system. The requirements review was separated into three areas: Optical Telescope Assembly (OTA), Fine Guidance Sensing and astrometry. The results show that the detectors should be installed directly onto the focal surface presented by the optics. This would maximize throughput and minimize point stability error by not incoporating any additional optical elements.

  4. Catalysts possessing augmented C-O and C-N hydrogenolysis activity. Preliminary progress report, August-September 1983

    SciTech Connect

    Massoth, F.E.; Shabtai, J.S.

    1983-10-31

    The aim of the proposed research is to synthesize and investigate new sulfided catalyst systems having higher carbon-heteroatom hydrogenolysis activity as compared to ring hydrogenation activity. A fundamental approach is planned to gain understanding of the basic catalytic properties which relate to hydrogenolysis, hydrogenation and cracking functions of the catalysts. This will involve preparation of new catalysts, characterization of their properties and model compound reactivity studies. In another part of the project, selected catalysts will be applied in studies of more complex O- and N-containing model compounds with the objective of providing fundamental data on the stereochemistry of HDO and HDN reactions. These data will be used to develop steric surface-reactant models for sulfided catalysts. These new catalysts should be of particular importance for upgrading of coal-derived liquids and solids, as well as other heavy feedstocks. The research is divided into four tasks: (1) catalyst preparation and activity testing; (2) catalyst characterization; (2) study of catalyst activity under hydroprocessing conditions; and (4) stereochemical studies. This report covers a period of only one month. Work was initiated on catalyst preparation. A brief literature search was made to ascertain what different preparation methods can be applied to supported sulfide catalysts besides the standard wetness method. Several Cr/Al/sub 2/O/sub 3/ catalysts containing Co or Ni were prepared by the standard impregnation method. 3 references.

  5. Catalyst increases COS conversion

    SciTech Connect

    Goodboy, K.P.

    1985-02-18

    Increasingly stringent air quality legislation is placing greater emphasis on conversion of COS and CS/sub 2/ in Claus plants for the maximum sulfur recovery. Overall sulfur recovery goals are dependent upon outstanding service from the Claus catalyst in each reactor because catalyst activity is a major factor influencing plant performance. Today's catalyst are much improved over those used 10 years ago for the Claus (H/sub 2/S/SO/sub 2/) reaction. Recent technical efforts have focused on the conversion of COS and CS/sub 2/. These carbon-sulfur compounds can account for as much as 50% of the sulfur going to the incinerator, which essentially converts all remaining sulfur species to SO/sub 2/ for atmospheric dispersion. Previously, the mechanism of Claus COS conversion, i.e., hydrolysis or oxidation by SO/sub 2/, was studied and the conclusion was that oxidation by SO/sub 2/ appears to be the predominate mode of COS conversion on sulfated alumina catalysts.

  6. Nanopore and nanoparticle catalysts.

    PubMed

    Thomas, J M; Raja, R

    2001-01-01

    The design, atomic characterization, performance, and relevance to clean technology of two distinct categories of new nanocatalysts are described and interpreted. Exceptional molecular selectivity and high activity are exhibited by these catalysts. The first category consists of extended, crystallographically ordered inorganic solids possessing nanopores (apertures, cages, and channels), the diameters of which fall in the range of about 0.4 to about 1.5 nm, and the second of discrete bimetallic nanoparticles of diameter 1 to 2 nm, distributed more or less uniformly along the inner walls of mesoporous (ca. 3 to 10 nm diameter) silica supports. Using the principles and practices of solid-state and organometallic chemistry and advanced physico-chemical techniques for in situ and ex situ characterization, a variety of powerful new catalysts has been evolved. Apart from those that, inter alia, simulate the behavior of enzymes in their specificity, shape selectivity, regio-selectivity, and ability to function under ambient conditions, many of these new nanocatalysts are also viable as agents for effecting commercially significant processes in a clean, benign, solvent-free, single-step fashion. In particular, a bifunctional, molecular sieve nanopore catalyst is described that converts cyclohexanone in air and ammonia to its oxime and caprolactam, and a bimetallic nanoparticle catalyst that selectively converts cyclic polyenes into desirable intermediates. Nanocatalysts in the first category are especially effective in facilitating highly selective oxidations in air, and those in the second are well suited to effecting rapid and selective hydrogenations of a range of organic compounds.

  7. Sabatier Catalyst Poisoning Investigation

    NASA Technical Reports Server (NTRS)

    Nallette, Tim; Perry, Jay; Abney, Morgan; Knox, Jim; Goldblatt, Loel

    2013-01-01

    The Carbon Dioxide Reduction Assembly (CRA) on the International Space Station (ISS) has been operational since 2010. The CRA uses a Sabatier reactor to produce water and methane by reaction of the metabolic CO2 scrubbed from the cabin air and the hydrogen byproduct from the water electrolysis system used for metabolic oxygen generation. Incorporating the CRA into the overall air revitalization system has facilitated life support system loop closure on the ISS reducing resupply logistics and thereby enhancing longer term missions. The CRA utilizes CO2 which has been adsorbed in a 5A molecular sieve within the Carbon Dioxide Removal Assembly, CDRA. There is a potential of compounds with molecular dimensions similar to, or less than CO2 to also be adsorbed. In this fashion trace contaminants may be concentrated within the CDRA and subsequently desorbed with the CO2 to the CRA. Currently, there is no provision to remove contaminants prior to entering the Sabatier catalyst bed. The risk associated with this is potential catalyst degradation due to trace organic contaminants in the CRA carbon dioxide feed acting as catalyst poisons. To better understand this risk, United Technologies Aerospace System (UTAS) has teamed with MSFC to investigate the impact of various trace contaminants on the CRA catalyst performance at relative ISS cabin air concentrations and at about 200/400 times of ISS concentrations, representative of the potential concentrating effect of the CDRA molecular sieve. This paper summarizes our initial assessment results.

  8. Catalyst, 2000-01.

    ERIC Educational Resources Information Center

    Ryan, Barbara E., Ed.

    2001-01-01

    "Catalyst" is a publication designed to assist higher education in developing alcohol and other drug prevention polices and programs that will foster students' academic and social development and promote campus and community safety. Issue 1 of volume 6 introduces a series of "Presidential Profiles" in which university presidents describe their…

  9. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  10. Octane boosting catalyst

    SciTech Connect

    Miller, J.G.; Pellet, R.J.; Shamshoun, E.S.; Rabo, J.A

    1989-02-07

    The invention provides petroleum cracking and octane boosting catalysts containing a composite of an intermediate pore NZMS in combination with another non-zeolitic molecular sieve having the same framework structure, and processes for cracking of petroleum for the purpose of enhancing the octane rating of the gasoline produced.

  11. Zinc sulfide liquefaction catalyst

    DOEpatents

    Garg, Diwakar

    1984-01-01

    A process for the liquefaction of carbonaceous material, such as coal, is set forth wherein coal is liquefied in a catalytic solvent refining reaction wherein an activated zinc sulfide catalyst is utilized which is activated by hydrogenation in a coal derived process solvent in the absence of coal.

  12. Shape-selective sieving layers on an oxide catalyst surface.

    PubMed

    Canlas, Christian P; Lu, Junling; Ray, Natalie A; Grosso-Giordano, Nicolas A; Lee, Sungsik; Elam, Jeffrey W; Winans, Randall E; Van Duyne, Richard P; Stair, Peter C; Notestein, Justin M

    2012-12-01

    New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al(2)O(3) (thickness, 0.4-0.7 nm) with 'nanocavities' (<2 nm in diameter) on a TiO(2) photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations. PMID:23174984

  13. Shape-selective sieving layers on an oxide catalyst surface

    NASA Astrophysics Data System (ADS)

    Canlas, Christian P.; Lu, Junling; Ray, Natalie A.; Grosso-Giordano, Nicolas A.; Lee, Sungsik; Elam, Jeffrey W.; Winans, Randall E.; van Duyne, Richard P.; Stair, Peter C.; Notestein, Justin M.

    2012-12-01

    New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al2O3 (thickness, 0.4-0.7 nm) with ‘nanocavities’ (<2 nm in diameter) on a TiO2 photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations.

  14. Noble metal ionic catalysts.

    PubMed

    Hegde, M S; Madras, Giridhar; Patil, K C

    2009-06-16

    Because of growing environmental concerns and increasingly stringent regulations governing auto emissions, new more efficient exhaust catalysts are needed to reduce the amount of pollutants released from internal combustion engines. To accomplish this goal, the major pollutants in exhaust-CO, NO(x), and unburned hydrocarbons-need to be fully converted to CO(2), N(2), and H(2)O. Most exhaust catalysts contain nanocrystalline noble metals (Pt, Pd, Rh) dispersed on oxide supports such as Al(2)O(3) or SiO(2) promoted by CeO(2). However, in conventional catalysts, only the surface atoms of the noble metal particles serve as adsorption sites, and even in 4-6 nm metal particles, only 1/4 to 1/5 of the total noble metal atoms are utilized for catalytic conversion. The complete dispersion of noble metals can be achieved only as ions within an oxide support. In this Account, we describe a novel solution to this dispersion problem: a new solution combustion method for synthesizing dispersed noble metal ionic catalysts. We have synthesized nanocrystalline, single-phase Ce(1-x)M(x)O(2-delta) and Ce(1-x-y)Ti(y)M(x)O(2-delta) (M = Pt, Pd, Rh; x = 0.01-0.02, delta approximately x, y = 0.15-0.25) oxides in fluorite structure. In these oxide catalysts, Pt(2+), Pd(2+), or Rh(3+) ions are substituted only to the extent of 1-2% of Ce(4+) ion. Lower-valent noble metal ion substitution in CeO(2) creates oxygen vacancies. Reducing molecules (CO, H(2), NH(3)) are adsorbed onto electron-deficient noble metal ions, while oxidizing (O(2), NO) molecules are absorbed onto electron-rich oxide ion vacancy sites. The rates of CO and hydrocarbon oxidation and NO(x) reduction (with >80% N(2) selectivity) are 15-30 times higher in the presence of these ionic catalysts than when the same amount of noble metal loaded on an oxide support is used. Catalysts with palladium ion dispersed in CeO(2) or Ce(1-x)Ti(x)O(2) were far superior to Pt or Rh ionic catalysts. Therefore, we have demonstrated that the

  15. New fine structure cooling rate

    NASA Technical Reports Server (NTRS)

    Hoegy, W. R.

    1976-01-01

    One of the dominant electron cooling processes in the ionosphere is caused by electron impact induced fine structure transitions among the ground state levels of atomic oxygen. This fine structure cooling rate is based on theoretical cross sections. Recent advances in the numerical cross section determinations to include polarization effects and more accurate representations of the atomic target result in new lower values. These cross sections are employed in this paper to derive a new fine structure cooling rate which is between 40% and 60% of the currently used rate. A new generalized formula is presented for the cooling rate (from which the fine structure cooling rate is derived), valid for arbitrary mass and temperature difference of the colliding particles and arbitrary inelastic energy difference.

  16. Sulfur condensation in Claus catalyst

    SciTech Connect

    Schoffs, G.R.

    1985-02-01

    The heterogeneous reactions in which catalyst deactivation by pore plugging occur are listed and include: coke formation in petroleum processing, especially hydrocracking and hydrodesulfurization catalysts; steam reforming and methnation catalysts; ammonia synthesis catalyst; and automobile exhause catalysts. The authors explain how the Claus process converts hydrogen sulfide produced by petroleum desulfurization units and gas treatment processes into elemental sulfur and water. More than 15 million tons of sulfur are recovered annually by this process. Commercial Claus plants appear to operate at thermodynamic equilibrium. Depending on the H2S content of the feed and the number of reactors, total H2S conversion to elemental sulfur can exceed 95%.

  17. Molybdenum sulfide/carbide catalysts

    DOEpatents

    Alonso, Gabriel; Chianelli, Russell R.; Fuentes, Sergio; Torres, Brenda

    2007-05-29

    The present invention provides methods of synthesizing molybdenum disulfide (MoS.sub.2) and carbon-containing molybdenum disulfide (MoS.sub.2-xC.sub.x) catalysts that exhibit improved catalytic activity for hydrotreating reactions involving hydrodesulfurization, hydrodenitrogenation, and hydrogenation. The present invention also concerns the resulting catalysts. Furthermore, the invention concerns the promotion of these catalysts with Co, Ni, Fe, and/or Ru sulfides to create catalysts with greater activity, for hydrotreating reactions, than conventional catalysts such as cobalt molybdate on alumina support.

  18. Pulse swallowing frequency divider with low power and compact structure

    NASA Astrophysics Data System (ADS)

    Haijun, Gao; Lingling, Sun; Chaobo, Cai; Haiting, Zhan

    2012-11-01

    A pulse swallowing frequency divider with low power and compact structure is presented. One of the DFFs in the divided by 2/3 prescaler is controlled by the modulus control signal, and automatically powered off when it has no contribution to the operation of the prescaler. The DFFs in the program counter and the swallow counter are shared to compose a compact structure, which reduces the power consumption further. The proposed multi-modulus frequency divider was implemented in a standard 65 nm CMOS process with an area of 28 × 22 μm2. The power consumption of the divider is 0.6 mW under 1.2 V supply voltage when operating at 988 MHz.

  19. Geology of photo linear elements, Great Divide Basin, Wyoming

    NASA Technical Reports Server (NTRS)

    Blackstone, D. L., Jr.

    1973-01-01

    The author has identified the following significant results. Ground examination of photo linear elements in the Great Divide Basin, Wyoming indicates little if any tectonic control. Aeolian aspects are more widespread and pervasive than previously considered.

  20. Narrowing the Digital Divide in Low-Income, Urban Communities

    ERIC Educational Resources Information Center

    Norris, Daniel T.; Conceicao, Simone

    2004-01-01

    The digital divide is leaving millions disenfranchised from the opportunity to use technology to change their lives and to participate fully in democracy, in their own communities, and in today's job market.

  1. Transport of fine sediment over a coarse, immobile riverbed

    USGS Publications Warehouse

    Grams, Paul E.; Wilcock, Peter R.

    2014-01-01

    Sediment transport in cobble-boulder rivers consists mostly of fine sediment moving over a coarse, immobile bed. Transport rate depends on several interrelated factors: boundary shear stress, the grain size and volume of fine sediment, and the configuration of fine sediment into interstitial deposits and bed forms. Existing models do not incorporate all of these factors. Approaches that partition stress face a daunting challenge because most of the boundary shear is exerted on immobile grains. We present an alternative approach that divides the bed into sand patches and interstitial deposits and is well constrained by two clear end-member cases: full sand cover and absence of sand. Entrainment from sand patches is a function of their aerial coverage. Entrainment from interstices among immobile grains is a function of sand elevation relative to the size of the immobile grains. The bed-sand coverage function is used to predict the ratio of the rate of entrainment from a partially covered bed to the rate of entrainment from a completely sand-covered bed, which is determined using a standard sand transport model. We implement the bed-sand coverage function in a morphodynamic routing model and test it against observations of sand bed elevation and suspended sand concentration for conditions of nonuniform fine sediment transport in a large flume with steady uniform flow over immobile hemispheres. The results suggest that this approach may provide a simple and robust method for predicting the transport and migration of fine sediment through rivers with coarse, immobile beds.

  2. A Rhodium Nanoparticle-Lewis Acidic Ionic Liquid Catalyst for the Chemoselective Reduction of Heteroarenes.

    PubMed

    Karakulina, Alena; Gopakumar, Aswin; Akçok, İsmail; Roulier, Bastien L; LaGrange, Thomas; Katsyuba, Sergey A; Das, Shoubhik; Dyson, Paul J

    2016-01-01

    We describe a catalytic system composed of rhodium nanoparticles immobilized in a Lewis acidic ionic liquid. The combined system catalyzes the hydrogenation of quinolines, pyridines, benzofurans, and furan to access the corresponding heterocycles, important molecules present in fine chemicals, agrochemicals, and pharmaceuticals. The catalyst is highly selective, acting only on the heteroaromatic ring, and not interfering with other reducible functional groups.

  3. Selective methane oxidation over promoted oxide catalysts. Topical report, September 8, 1992--September 7, 1996

    SciTech Connect

    Klier, K.; Herman, R.G.

    1996-12-31

    The objective of this research was to selectively oxidize methane to C{sub 2} hydrocarbons and to oxygenates, in particular formaldehyde and methanol, in high space time yields using air at the oxidant under milder reaction conditions that heretofore employed over industrially practical oxide catalysts. The research carried out under this US DOE-METC contract was divided into the following three tasks: Task 1, maximizing selective methane oxidation to C{sub 2}{sup +} products over promoted SrO/La{sub 2}O{sub 3} catalysts; Task 2, selective methane oxidation to oxygenates; and Task 3, catalyst characterization and optimization. Principal accomplishments include the following: the 1 wt% SO{sub 4}{sup 2{minus}}/SrO/La{sub 2}O{sub 3} promoted catalyst developed here produced over 2 kg of C{sub 2} hydrocarbons/kg catalyst/hr at 550 C; V{sub 2}O{sub 5}/SiO{sub 2} catalysts have been prepared that produce up to 1.5 kg formaldehyde/kg catalyst/hr at 630 C with low CO{sub 2} selectivities; and a novel dual bed catalyst system has been designed and utilized to produce over 100 g methanol/kg catalyst/hr at 600 C with the presence of steam in the reactant mixture.

  4. Fluorination process using catalyst

    DOEpatents

    Hochel, Robert C.; Saturday, Kathy A.

    1985-01-01

    A process for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3, AgF.sub.2 and NiF.sub.2, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF.sub.3 and AgF.sub.2, whereby the fluorination is significantly enhanced.

  5. Fluorination process using catalysts

    DOEpatents

    Hochel, R.C.; Saturday, K.A.

    1983-08-25

    A process is given for converting an actinide compound selected from the group consisting of uranium oxides, plutonium oxides, uranium tetrafluorides, plutonium tetrafluorides and mixtures of said oxides and tetrafluorides, to the corresponding volatile actinide hexafluoride by fluorination with a stoichiometric excess of fluorine gas. The improvement involves conducting the fluorination of the plutonium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/, AgF/sub 2/ and NiF/sub 2/, whereby the fluorination is significantly enhanced. The improvement also involves conducting the fluorination of one of the uranium compounds in the presence of a fluoride catalyst selected from the group consisting of CoF/sub 3/ and AgF/sub 2/, whereby the fluorination is significantly enhanced.

  6. New microbead cracking catalysts

    SciTech Connect

    Nefedov, S.K.; Guseinov, A.M.; Il'ina, L.M.; Melik-Akhnazarov, T.K.; Stankevich, V.A.

    1984-05-01

    This article reports on the preparation and testing of an experimental batch of KMTsU catalysts using a cocurrent-flow fluid-bed reactor. The proposed manufacturing process is based on the regulation of the density and pore structure of an aluminosilicate matrix by varying the conditions of syneresis and wet treatment in the activation stage. It is recommended that the medium should be at a lower pH in obtaining the gel, that the temperature and pH of the medium should be lower in the activation stage, and that additional dispersion of the gel should be accomplished before spray-drying. The results of the tests on the KMTsU catalyst demonstrate its sufficiently high stable activity, high density (900-920 kg/m/sup 3/), and attrition resistance (92-94%).

  7. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, Gerald P.; Zhao, Jianmin; Feng, Zhen

    1996-01-01

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered.

  8. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, G.P.; Zhao, J.; Feng, Z.

    1996-12-03

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered. 3 figs.

  9. FCC catalyst selection

    SciTech Connect

    Carter, G.D.L. ); McElhiney, G. )

    1989-09-01

    This paper discusses a commonly used technique for comparing FCC catalytic selectivities based on the ASTM microactivity test (MAT) procedure, ASTM D-3907-80. In its original form the ASTM test provides only very limited information on selectivity. However, extension of the ASTM MAT procedure by using additional product analyses gives a microselectivity test capable of providing detailed yield structure information. This modified MAT procedure thus provides a cost-effective and rapid means of comparing many catalysts.

  10. Steam reforming catalyst

    DOEpatents

    Kramarz, Kurt W.; Bloom, Ira D.; Kumar, Romesh; Ahmed, Shabbir; Wilkenhoener, Rolf; Krumpelt, Michael

    2001-01-01

    A method of forming a hydrogen rich gas from a source of hydrocarbon fuel. A vapor of the hydrocarbon fuel and steam is brought in contact with a two-part catalyst having a dehydrogenation powder portion and an oxide-ion conducting powder portion at a temperature not less than about 770.degree.C. for a time sufficient to generate the hydrogen rich. The H.sub.2 content of the hydrogen gas is greater than about 70 percent by volume. The dehydrogenation portion of the catalyst includes a group VIII metal, and the oxide-ion conducting portion is selected from a ceramic oxide from the group crystallizing in the fluorite or perovskite structure and mixtures thereof. The oxide-ion conducting portion of the catalyst is a ceramic powder of one or more of ZrO.sub.2, CeO.sub.2, Bi.sub.2 O.sub.3, (BiVO).sub.4, and LaGaO.sub.3.

  11. Dividing Cells Regulate Their Lipid Composition and Localization

    PubMed Central

    Atilla-Gokcumen, G. Ekin; Muro, Eleonora; Relat-Goberna, Josep; Sasse, Sofia; Bedigian, Anne; Coughlin, Margaret L.; Garcia-Manyes, Sergi; Eggert, Ulrike S.

    2014-01-01

    Summary Although massive membrane rearrangements occur during cell division, little is known about specific roles that lipids might play in this process. We report that the lipidome changes with the cell cycle. LC-MS-based lipid profiling shows that 11 lipids with specific chemical structures accumulate in dividing cells. Using AFM, we demonstrate differences in the mechanical properties of live dividing cells and their isolated lipids relative to nondividing cells. In parallel, systematic RNAi knockdown of lipid biosynthetic enzymes identified enzymes required for division, which highly correlated with lipids accumulated in dividing cells. We show that cells specifically regulate the localization of lipids to midbodies, membrane-based structures where cleavage occurs. We conclude that cells actively regulate and modulate their lipid composition and localization during division, with both signaling and structural roles likely. This work has broader implications for the active and sustained participation of lipids in basic biology. PMID:24462247

  12. REDUCTION OF NO{sub x} VIA COAL COMBUSTION CATALYSTS

    SciTech Connect

    Jeff Hare; George Ford; Stephanie Black; Bing Zhou; Stan Harding

    2004-02-13

    Air pollution is a growing concern for both the US government and its citizens. Current legislation is moving in the direction of lower emissions standards for the major pollutants, SO{sub x} and NO{sub x}. The work performed under this DOE grant focused on finding a catalyst that, when added to coal, will effectively reduce the amount of NO{sub x} produced during combustion. The test program was divided into four major tasks: (1) evaluating the impact of a combustion catalyst on nitrogen release; (2) optimizing catalyst formulation; (3) preparing a preliminary economic evaluation; and (4) outlining future test plans, costs and schedule. More than 100 bench-scale, proof-of-concept tests were completed with more than 30 different catalysts, using two different coal types, River Hill Pittsburgh 8 (River Hill) and PRB, under oxidizing and reducing conditions. The results showed that catalysts were effective in increasing, by more than 30%, the nitrogen gas (N{sub 2}) release in River Hill Pittsburgh 8 coal and more than 20% in the PRB coal. Preliminary economics suggest this technology is comparable with current combustion NO{sub x} control technologies such as overfire air addition, SNCR and reburning. Pilot-scale tests are planned in a system with low-NO{sub x} burners to further evaluate the technology.

  13. Histological findings of divided muscle after peroral endoscopic myotomy

    PubMed Central

    Shiwaku, Hironari; Inoue, Haruhiro; Nimura, Satoshi; Yamashita, Kanefumi; Ohmiya, Toshihiro; Takeno, Shinsuke; Sasaki, Takamitsu; Yamashita, Yuichi

    2016-01-01

    Peroral endoscopic myotomy (POEM) is a revolutionary therapy for achalasia and related disorders. POEM utilizes almost the same myotomy procedure as the Heller myotomy; thus, it would be expected to have the same or greater duration of therapeutic effect. However, to date, there have been no reports to prove the basis for this procedure in achalasia. In this case, we were able to histologically show the divided muscle after POEM since the patient had an esophagectomy for esophageal cancer. Histology showed that the muscle tissue divided by the POEM procedure was completely replaced by fibrosis. These findings may indirectly show the permanence of the POEM procedure. PMID:26752956

  14. Compact waveguide power divider with multiple isolated outputs

    DOEpatents

    Moeller, Charles P.

    1987-01-01

    A waveguide power divider (10) for splitting electromagnetic microwave power and directionally coupling the divided power includes an input waveguide (21) and reduced height output waveguides (23) interconnected by axial slots (22) and matched loads (25) and (26) positioned at the unused ends of input and output guides (21) and (23) respectively. The axial slots are of a length such that the wave in the input waveguide (21) is directionally coupled to the output waveguides (23). The widths of input guide (21) and output guides (23) are equal and the width of axial slots (22) is one half of the width of the input guide (21).

  15. Resynchronization in neuronal network divided by femtosecond laser processing.

    PubMed

    Hosokawa, Chie; Kudoh, Suguru N; Kiyohara, Ai; Taguchi, Takahisa

    2008-05-01

    We demonstrated scission of a living neuronal network on multielectrode arrays (MEAs) using a focused femtosecond laser and evaluated the resynchronization of spontaneous electrical activity within the network. By an irradiation of femtosecond laser into hippocampal neurons cultured on a multielectrode array dish, neurites were cut at the focal point. After the irradiation, synchronization of neuronal activity within the network drastically decreased over the divided area, indicating diminished functional connections between neurons. Cross-correlation analysis revealed that spontaneous activity between the divided areas gradually resynchronized within 10 days. These findings indicate that hippocampal neurons have the potential to regenerate functional connections and to reconstruct a network by self-assembly. PMID:18418255

  16. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, Wolfgang M. H.; Tzou, Ming-Shin; Jiang, Hui-Jong

    1987-01-01

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  17. Dispersion enhanced metal/zeolite catalysts

    DOEpatents

    Sachtler, W.M.H.; Tzou, M.S.; Jiang, H.J.

    1987-03-31

    Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

  18. Coarse-fine adaptive tuned vibration absorber with high frequency resolution

    NASA Astrophysics Data System (ADS)

    Wang, Xi; Yang, Bintang; You, Jiaxin; Gao, Zhe

    2016-11-01

    The speed fluctuation of satellite-rotary-mechanisms causes vibration of slightly different frequencies. The critical requirements of satellites need a vibration control device with high frequency resolution to suppress the vibration. This paper presents a coarse-fine adaptive tuned vibration absorber (ATVA) with high frequency resolution. The coarse-fine ATVA which simultaneously satisfies the requirements of high resolution and relatively wide effective bandwidth is capable of tracking the variable exciting frequency adaptively to suppress the vibration of the primary system. The coarse-fine ATVA is divided into a coarse tuning segment and a fine tuning segment. The coarse tuning segment is used to tune the required natural frequency in a relatively wide effective bandwidth and the fine tuning segment can achieve precise tune in a tiny-scale bandwidth. The mathematical model of the coarse tuning and the fine tuning is proposed to design the parameters of the coarse-fine ATVA. The experimental test results indicate the coarse tuning bandwidth of the coarse-fine ATVA is 8.7 Hz to 29 Hz and the minimum resolution of the fine tuning is 0.05 Hz. Moreover, a significant vibration attenuation of 15dB is verified in the effective bandwidth.

  19. Development of GREET Catalyst Module

    SciTech Connect

    Wang, Zhichao; Benavides, Pahola T.; Dunn, Jennifer B.; Cronauer, Donald C.

    2015-09-01

    In this report, we develop energy and material flows for the production of five different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5], Mo/Co/ γ-Al2O3, and Pt/ γ-Al2O3) and two chemicals (olivine, dimethyl ether of polyethylene glycol [DEPG]). These compounds and catalysts are now included in the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET™) catalyst module.

  20. Oxygen-reducing catalyst layer

    DOEpatents

    O'Brien, Dennis P.; Schmoeckel, Alison K.; Vernstrom, George D.; Atanasoski, Radoslav; Wood, Thomas E.; Yang, Ruizhi; Easton, E. Bradley; Dahn, Jeffrey R.; O'Neill, David G.

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  1. Catalyst systems and uses thereof

    SciTech Connect

    Ozkan, Umit S.; Holmgreen, Erik M.; Yung, Matthew M.

    2012-07-24

    A method of carbon monoxide (CO) removal comprises providing an oxidation catalyst comprising cobalt supported on an inorganic oxide. The method further comprises feeding a gaseous stream comprising CO, and oxygen (O.sub.2) to the catalyst system, and removing CO from the gaseous stream by oxidizing the CO to carbon dioxide (CO.sub.2) in the presence of the oxidation catalyst at a temperature between about 20 to about 200.degree. C.

  2. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Burtron H. Davis

    2005-09-30

    In this reporting period, a study of ultra-fine iron catalyst filtration was initiated to study the behavior of ultra-fine particles during the separation of Fischer-Tropsch Synthesis (FTS) liquids filtration. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. The change of particle size during the slurry-phase FTS has monitored by withdrawing catalyst sample at different TOS. The measurement of dimension of the HRTEM images of samples showed a tremendous growth of the particles. Carbon rims of thickness 3-6 nm around the particles were observed. This growth in particle size was not due to carbon deposition on the catalyst. A conceptual design and operating philosophy was developed for an integrated wax filtration system for a 4 liter slurry bubble column reactor to be used in Phase II of this research program. The system will utilize a primary inertial hydroclone followed by a Pall Accusep cross-flow membrane. Provisions for cleaned permeate back-pulsing will be included to as a flux maintenance measure.

  3. Results of catalyst testing using iron-based catalysts

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.

    1993-03-01

    As coal liquefaction catalysts, iron-based products are generally inferior to the more expensive molybdenum, cobalt, or nickel-based materials. However, the lower costs of production and recovery (or in the case of some iron catalysts, non-recovery) give the iron-based materials a potential economic advantage over the more efficient precious and semi-precious metal catalysts for this application. Recent research has shown that a number of different iron-containing materials can be successfully utilized as coal liquefaction catalysts or as catalyst. Pyrrhotite (Fe[sub 1-x]S) or a similar iron-sulfide phase is commonly believed to be the active catalyst in coal liquefaction and model compound pyrolysis reactions, although no specific phase has been yet been isolated as the actual catalyst species. The active iron-containing catalyst is usually generated in situ from an iron-oxide precursor and an elemental sulfur source under reducing conditions in the reactor vessel. Most research has concentrated on the use of common iron-oxide phases such as hematite or goethite (and their derivatives) as the iron-bearing precursor, or on non-specific iron materials produced by the reaction of various iron salts and compounds in the coal or liquefaction reactor. To our knowledge there has been no systematic effort to determine the optimum iron-containing precursor phase for producing active coal liquefaction catalysts, despite the fact that there are over ten iron-(hydroxy)oxide phases which can be easily synthesized in the laboratory. We have undertaken a systematic study to identify the most active iron-oxide catalyst precursor phases, the co-catalysts, and the coal pretreatments which will provide optimum yields in coal liquefaction processes.

  4. Results of catalyst testing using iron-based catalysts

    SciTech Connect

    Linehan, J.C.; Darab, J.G.; Matson, D.W.

    1993-03-01

    As coal liquefaction catalysts, iron-based products are generally inferior to the more expensive molybdenum, cobalt, or nickel-based materials. However, the lower costs of production and recovery (or in the case of some iron catalysts, non-recovery) give the iron-based materials a potential economic advantage over the more efficient precious and semi-precious metal catalysts for this application. Recent research has shown that a number of different iron-containing materials can be successfully utilized as coal liquefaction catalysts or as catalyst. Pyrrhotite (Fe{sub 1-x}S) or a similar iron-sulfide phase is commonly believed to be the active catalyst in coal liquefaction and model compound pyrolysis reactions, although no specific phase has been yet been isolated as the actual catalyst species. The active iron-containing catalyst is usually generated in situ from an iron-oxide precursor and an elemental sulfur source under reducing conditions in the reactor vessel. Most research has concentrated on the use of common iron-oxide phases such as hematite or goethite (and their derivatives) as the iron-bearing precursor, or on non-specific iron materials produced by the reaction of various iron salts and compounds in the coal or liquefaction reactor. To our knowledge there has been no systematic effort to determine the optimum iron-containing precursor phase for producing active coal liquefaction catalysts, despite the fact that there are over ten iron-(hydroxy)oxide phases which can be easily synthesized in the laboratory. We have undertaken a systematic study to identify the most active iron-oxide catalyst precursor phases, the co-catalysts, and the coal pretreatments which will provide optimum yields in coal liquefaction processes.

  5. Mixed Alcohol Synthesis Catalyst Screening

    SciTech Connect

    Gerber, Mark A.; White, James F.; Stevens, Don J.

    2007-09-03

    National Renewable Energy Laboratory (NREL) and Pacific Northwest National Laboratory (PNNL) are conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). PNNL is tasked with obtaining commercially available or preparing promising mixed-alcohol catalysts and screening them in a laboratory-scale reactor system. Commercially available catalysts and the most promising experimental catalysts are provided to NREL for testing using a slipstream from a pilot-scale biomass gasifier. From the standpoint of producing C2+ alcohols as the major product, it appears that the rhodium catalyst is the best choice in terms of both selectivity and space-time yield (STY). However, unless the rhodium catalyst can be improved to provide minimally acceptable STYs for commercial operation, mixed alcohol synthesis will involve significant production of other liquid coproducts. The modified Fischer-Tropsch catalyst shows the most promise for providing both an acceptable selectivity to C2+ alcohols and total liquid STY. However, further optimization of the Fischer-Tropsch catalysts to improve selectivity to higher alcohols is highly desired. Selection of a preferred catalyst will likely entail a decision on the preferred coproduct slate. No other catalysts tested appear amenable to the significant improvements needed for acceptable STYs.

  6. The Digital Divide and Its Impact on Academic Performance

    ERIC Educational Resources Information Center

    Sun, Jerry Chih-Yuan; Metros, Susan E.

    2011-01-01

    The purpose of this article is to explore issues of the digital divide and its impact on academic performance. Research shows that proper use of technology by students increases their academic performance outcomes. In the literature review section, the authors review articles and theories based on Bennett's (2001) societal equity framework. The…

  7. From Fundamentalists to Structuralists: Bridging the Digital Divide

    ERIC Educational Resources Information Center

    Kok, Ayse

    2010-01-01

    The purpose of this literature review is to provide information about several ICT initiatives undertaken in education on a global basis in order to overcome the digital divide and summarise the findings of these initiatives. Due to the limited scope of the study, the bulk of the review mainly concerns initiatives undertaken in secondary schools,…

  8. New Literacies at the Digital Divide: American Indian Community Computing

    ERIC Educational Resources Information Center

    Betts, J. David

    2009-01-01

    This study is about a community computing lab established by a U.S. Department of Commerce grant to bridge the Digital Divide in a rural Arizona American Indian community, a project called "Native Connection" (a pseudonym). This paper describes the process of integrating new literacies associated with a high-tech computer lab into the life of a…

  9. Peculiarities of the Digital Divide in Sub-Saharan Africa

    ERIC Educational Resources Information Center

    Mutula, Stephen M.

    2005-01-01

    Purpose: Seeks to argue that the peculiarities of sub-Saharan Africa, in terms of its socio-cultural diversity, low economic development, linguistic factors, HIV/AIDS pandemic, gender discrimination, low ICT awareness and so on, demand a new model of addressing the digital divide. Design/methodology/approach: Paper largely based on literature…

  10. Middle School Mathematics Students' Justification Schemes for Dividing Fractions

    ERIC Educational Resources Information Center

    Day, Melina Michele

    2010-01-01

    Three theoretical frameworks were used to guide this intervention case study: dividing fractions; sociomathematical norms, and justification. Middle school mathematics students were given the opportunity to solve partitive and measurement division of fraction word problems with different contexts. The teacher purposefully implemented a…

  11. Research and Practice in Education: Building Alliances, Bridging the Divide

    ERIC Educational Resources Information Center

    Coburn, Cynthia E., Ed.; Stein, Mary Kay, Ed.

    2010-01-01

    That there is a divide between research and practice is a common lament across policy-oriented disciplines, and education is no exception. Rhetoric abounds about the role research plays (or does not play) in the improvement of schools and classrooms, and policy makers push solutions that are rooted in assumptions about the way that research…

  12. Leadership Analysis in K-12 Case Study: "Divided Loyalties"

    ERIC Educational Resources Information Center

    Alsubaie, Merfat Ayesh

    2016-01-01

    This report mainly aims to provide a critical and in-depth analysis of the K-12 Case, "Divided Loyalty" by Holy and Tartar (2004). The case recounts how the manifestation of inadequate leadership skills in a school setting could affect negatively the performance of students.

  13. View looking to the arched entrances that divide the Departmental ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View looking to the arched entrances that divide the Departmental Auditorium from the Interstate Commerce Commission (east) and U.S. Customs Agency (originally Labor Department to the west) - Departmental Auditorium, Constitution Avenue between Twelfth and Fourteenth Streets, Washington, District of Columbia, DC

  14. Dividing Any Angle into Any Number of Equal Parts.

    ERIC Educational Resources Information Center

    Hutcheson, Thomas W.

    2001-01-01

    Presents two ancient problems, trisecting any angle and dividing a circle into any number of equal parts. Illustrates how to use these problems to prompt students to think broadly and creatively about problems instead of letting the apparent boundaries of the problem limit their thoughts. Combines three-dimensional solutions to the problems to…

  15. The Digital Divide: The Special Case of Gender

    ERIC Educational Resources Information Center

    Cooper, J.

    2006-01-01

    This paper examines the evidence for the digital divide based on gender. An overview of research published in the last 20 years draws to the conclusion that females are at a disadvantage relative to men when learning about computers or learning other material with the aid of computer-assisted software. The evidence shows that the digital divide…

  16. Response Styles and the Rural-Urban Divide

    ERIC Educational Resources Information Center

    Thomas, Troy D.; Abts, Koen; Vander Weyden, Patrick

    2014-01-01

    This article investigates the effect of the rural-urban divide on mean response styles (RSs) and their relationships with the sociodemographic characteristics of the respondents. It uses the Representative Indicator Response Style Means and Covariance Structure (RIRSMACS) method and data from Guyana--a developing country in the Caribbean. The…

  17. Teachers in the Social Trenches: Teaching Civics in Divided Societies

    ERIC Educational Resources Information Center

    Tamir, Yuli

    2015-01-01

    This article argues that in divided societies, civic education fails to fulfill one of its most important social role: creating a more inclusive society that allows a democratic dialogue to flow across different ideological, religious, and cultural communities. This failure is grounded in two main reasons. First, civics teachers are socially and…

  18. Effects of valence and divided attention on cognitive reappraisal processes

    PubMed Central

    Leclerc, Christina M.; Kensinger, Elizabeth A.

    2014-01-01

    Numerous studies have investigated the neural substrates supporting cognitive reappraisal, identifying the importance of cognitive control processes implemented by prefrontal cortex (PFC). This study examined how valence and attention affect the processes used for cognitive reappraisal by asking participants to passively view or to cognitively reappraise positive and negative images with full or divided attention. When participants simply viewed these images, results revealed few effects of valence or attention. However, when participants engaged in reappraisal, there was a robust effect of valence, with the reappraisal of negative relative to positive images associated with more widespread activation, including within regions of medial and lateral PFC. There also was an effect of attention, with more lateral PFC recruitment when regulating with full attention and more medial PFC recruitment when regulating with divided attention. Within two regions of medial PFC and one region of ventrolateral PFC, there was an interaction between valence and attention: in these regions, divided attention reduced activity during reappraisal of positive but not negative images. Critically, participants continued to report reappraisal success even during the Divided Attention condition. These results suggest multiple routes to successful cognitive reappraisal, depending upon image valence and the availability of attentional resources. PMID:24493837

  19. Closing the Digital Divide: Evaluation of the World Links Program

    ERIC Educational Resources Information Center

    Kozma, Robert; McGhee, Ray; Quellmalz, Edys; Zalles, Dan

    2004-01-01

    In response to this digital divide between developed and developing countries in their use of computers to prepare students for the global economy, the World Bank and, subsequently, the World Links organization provided schools in developing countries with networked computers and training that supports integration of ICT into teaching. This…

  20. Journalism Students, Web 2.0 and the Digital Divide

    ERIC Educational Resources Information Center

    Green, Mary Elizabeth

    2009-01-01

    The purpose of this study was to find out if students were utilizing Web 2.0 applications. Since the applications in question are often employed by the media industry, the study aspired to find out if students majoring in mass communication and journalism utilized the applications more often than other students. The "digital divide" is a term used…

  1. Dividing Attention Lowers Children's but Increases Adults' False Memories

    ERIC Educational Resources Information Center

    Otgaar, Henry; Peters, Maarten; Howe, Mark L.

    2012-01-01

    The present study examined the impact of divided attention on children's and adults' neutral and negative true and false memories in a standard Deese/Roediger-McDermott paradigm. Children (7- and 11-year-olds; n = 126) and adults (n = 52) received 5 neutral and 5 negative Deese/Roediger-McDermott word lists; half of each group also received a…

  2. Research Highlights. Strengths and Needs of Divided Families.

    ERIC Educational Resources Information Center

    Stringer-Seibold, Traci; And Others

    1996-01-01

    Describes a qualitative research study of children from divided families and analyzes findings in terms of family contexts, children's resiliency, and needs. Suggests strategies for professionals including recognition of developmental capacity within family circumstances, interactive systems, communication patterns and areas of stress. Includes…

  3. The Common Core State Standards and the Great Divide

    ERIC Educational Resources Information Center

    Wiley, Terrence G.; Rolstad, Kellie

    2014-01-01

    This article contextualizes recent developments around issues of language and the new Common Core State Standards (CCSS) in terms of the classic distinction between literates and non-literates in the Great Divide debate. Using a social practices perspective to frame the issues, the authors argue that the CCSS reiterate the debate, and reflect an…

  4. Digital Divide among Youth: Socio-Cultural Factors and Implications

    ERIC Educational Resources Information Center

    Parycek, Peter; Sachs, Michael; Schossbock, Judith

    2011-01-01

    Purpose: This paper aims to examine socio-cultural differences in internet use (Digital Divide) among 14-year-old Austrian pupils, in particular usage scenarios and research competences. It is based on a paper presented at the International Association for the Development of the Information Society e-Society conference, 10-13 March 2011, Spain…

  5. Digital Democracy in Higher Education: Bridging the Digital Divide

    ERIC Educational Resources Information Center

    Juniu, Susana

    2005-01-01

    Susana Juniu's thought-provoking essay defines the new digital divide in higher education--a division of knowledge, experience, and needs that influence the integration of technology into the classroom. She acknowledges educators' frequently conflicting feelings about technology as well as the lack of communication between IT departments and…

  6. Dismantling the Digital Divide: A Multicultural Education Framework.

    ERIC Educational Resources Information Center

    Gorski, Paul C.

    2002-01-01

    Describes inequities in access to computers by gender and race, drawing connections between the two and discussing the use of a multicultural education approach to understanding and eliminating the digital divide. This involves such actions as critiquing technology-related inequities in the context of larger educational and social inequities,…

  7. Advanced on-chip divider for monolithic microwave VCO's

    NASA Technical Reports Server (NTRS)

    Peterson, Weddell C.

    1989-01-01

    High frequency division on a monolithic circuit is a critical technology required to significantly enhance the performance of microwave and millimeter-wave phase-locked sources. The approach used to meet this need is to apply circuit design practices which are essentially 'microwave' in nature to the basically 'digital' problem of high speed division. Following investigation of several promising circuit approaches, program phase 1 culminated in the design and layout of an 8.5 GHz (Deep Space Channel 14) divide by four circuit based on a dynamic mixing divider circuit approach. Therefore, during program phase 2, an 8.5 GHz VCO with an integral divider which provides a phase coherent 2.125 GHz reference signal for phase locking applications was fabricated and optimized. Complete phase locked operation of the monolithic GaAs devices (VCO, power splitter, and dynamic divider) was demonstrated both individually and as an integrated unit. The fully functional integrated unit in a suitable test fixture was delivered to NASA for engineering data correlation. Based on the experience gained from this 8.5 GHz super component, a monolithic GaAs millimeter-wave dynamic divider for operation with an external VCO was also designed, fabricated, and characterized. This circuit, which was also delivered to NASA, demonstrated coherent division by four at an input frequency of 24.3 GHz. The high performance monolithic microwave VCO with a coherent low frequency reference output described in this report and others based on this technology will greatly benefit advanced communications systems in both the DoD and commercial sectors. Signal processing and instrumentation systems based on phase-locking loops will also attain enhanced performance at potentially reduced cost.

  8. Fine Arts in the Curriculum.

    ERIC Educational Resources Information Center

    Tuttle, Frederick B., Jr., Ed.

    In this anthology the issues related to the fine arts (music, theater, visual arts) in the elementary secondary curriculum are examined. The fifteen articles, ranging in length from one to seven pages, are followed by a biographical page briefly identifying the contributors. The articles are: "What's It All About?" (Frederick B. Tuttle, Jr.);…

  9. Swedish discovery: magnetic fines recovery

    SciTech Connect

    Hervol, J.D.

    1984-07-01

    A Swedish device, the Magnadisc, which recovers magnetite fines normally lost in tailings is described. The system was developed in the 1970s, but has reached the US only recently. Tests carried out by EPRI are reported and the results are presented. These indicate that the machine can recover a significant percentage of magnetite currently discharged in the tailings from magnetic drum separators.

  10. Regional Background Fine Particulate Matter

    EPA Science Inventory

    A modeling system composed of the global model GEOS-Chem providing hourly lateral boundary conditions to the regional model CMAQ was used to calculate the policy relevant background level of fine particulate: matter. Simulations were performed for the full year of 2004 over the d...

  11. Costar/foc Fine Alignment

    NASA Astrophysics Data System (ADS)

    Hartig, George

    1994-01-01

    The following activities will take place during this proposal. 1. Perform a 3x3 tilt scan centered on the current best FOC X-tilt and Y-tilt positions. Take an FOC image at each scan point. Perform a fine focus sweep. +/- 2, 1 mm and take an FOC image at each DOB point.

  12. Fine Arts. [SITE 2002 Section].

    ERIC Educational Resources Information Center

    Robin, Bernard, Ed.

    This document contains two papers on fine arts from the SITE (Society for Information Technology & Teacher Education) 2002 conference. "Expanding the Boundaries of the Music Education of the Elementary Teacher Classroom with Information Technology" (Cheryl Jackson) reports on how information technology is used in a music methods course for…

  13. Chemoselective single-site Earth-abundant metal catalysts at metal-organic framework nodes.

    PubMed

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X; Urban, Ania; Thacker, Nathan C; Lin, Wenbin

    2016-01-01

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal-organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C-H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  14. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    SciTech Connect

    Amitava Sarkar; James K. Neathery; Burtron H. Davis

    2006-12-31

    A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of iron catalyst particles and the formation of ultra-fine particles.

  15. Carbon nanocages: A new support material for Pt catalyst with remarkably high durability

    PubMed Central

    Wang, Xiao Xia; Tan, Zhe Hua; Zeng, Min; Wang, Jian Nong

    2014-01-01

    Low durability is the major challenge hindering the large-scale implementation of proton exchange membrane fuel cell (PEMFC) technology, and corrosion of carbon support materials of current catalysts is the main cause. Here, we describe the finding of remarkably high durability with the use of a novel support material. This material is based on hollow carbon nanocages developed with a high degree of graphitization and concurrent nitrogen doping for oxidation resistance enhancement, uniform deposition of fine Pt particles, and strong Pt-support interaction. Accelerated degradation testing shows that such designed catalyst possesses a superior electrochemical activity and long-term stability for both hydrogen oxidation and oxygen reduction relative to industry benchmarks of current catalysts. Further testing under conditions of practical fuel cell operation reveals almost no degradation over long-term cycling. Such a catalyst of high activity, particularly, high durability, opens the door for the next-generation PEMFC for “real world” application. PMID:24658614

  16. Chemoselective single-site Earth-abundant metal catalysts at metal-organic framework nodes

    NASA Astrophysics Data System (ADS)

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X.; Urban, Ania; Thacker, Nathan C.; Lin, Wenbin

    2016-08-01

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal-organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C-H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  17. DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE

    EPA Science Inventory

    The objectives of this project were to better understand the effect of different catalyst preparation parameters, the effect of different catalyst treatment parameters, and the mechanism of deactivation. Accordingly, catalysts were made using various preparation methods and with...

  18. Fine and coarse components in surface sediments from Bikini Lagoon

    SciTech Connect

    Noshkin, V. E., LLNL

    1997-01-01

    In 1979, 21 years after the moratorium on nuclear testing in the Marshall Islands, surface sediment samples (to depths of 2 and 4 cm) were collected from 87 locations in the lagoon of Bikini Atoll, one of the two sites in the Marshall Islands used by the United States to test nuclear devices from 1946 through 1958. The main purpose for the collections was to map the distribution of long-lived man-made radionuclides associated with the bottom material. In addition the samples were processed to estimate the fraction of fine and coarse components to show, by comparison, what modifications occurred in the composition since the sediments were first described in samples collected before testing in 1946. Nuclear testing produced more finely divided material that is now found in the surface sediment layer over large areas of the lagoon and especially in regions of the lagoon and reef adjacent to test sites. The 5 cratering events alone at Bikini Atoll redistributed sufficient material to account for the higher inventory of fine material found over the surface 4 cm of the sediment of the lagoon. Although the fraction of fine material in the bottom sediments was altered by the nuclear events, the combined processes of formation, transport and deposition were not sufficiently dynamic to greatly change the general geographical features of the major sedimentary components over most of the lagoon floor.

  19. Novel bimetallic dispersed catalysts for temperature-programmed coal liquefaction. Technical progress report, October--December 1992

    SciTech Connect

    Song, Chunshan; Schobert, H.H.

    1993-02-01

    Development of new catalysts is a promising approach to more efficient coal liquefaction. It has been recognized that catalysts are superior to supported catalysts for primary liquefaction of coals, because the control of initial coal dissolution or depolymerization requires intimate contact between the catalyst and coal. This research is a fundamental and exploratory study on catalytic coal liquefaction, with the emphasis on the development of novel bimetallic dispersed catalysts for temperature-programmed liquefaction. The ultimate goal of the present research is to develop novel catalytic hydroliquefaction process using highly active dispersed catalysts. The primary objective of this research is to develop novel bimetallic dispersed catalysts from organometallic molecular that can be used in low precursors concentrations (< 1 %) but exhibit high activity for efficient hydroliquefaction of coals under temperature-programmed conditions. The major technical approaches are, first, to prepare the desired heteronuclear organometallic molecules as catalyst precursors that contain covalently bound, two different metal atoms and sulfur in a single molecule. Such precursors will generate finely dispersed bimetallic catalysts such as Fe-Mo, Co-Mo and Ni-Mo binary sulfides upon thermal decomposition. The second major technical approach is to perform the liquefaction of coals unpregnated with the organometallic precursors under temperature-programmed conditions, where the programmed heat-up serves as a step for both catalyst activation and coal pretreatment or preconversion. Two to three different complexes for each of the Fe-Mo, Co-Mo, and Ni-Mo combinations will be prepared. Initial catalyst screening tests will be conducted using a subbituminous coal and a bituminous coal. Effects of coal rank and solvents will be examined with the selected bimetallic catalysts which showed much higher activity than the dispersed catalysts from conventional precursors.

  20. Catalyst for cracking kerosene

    SciTech Connect

    Hsie, C. H.

    1985-06-04

    A catalyst capable of cracking kerosene under lower pressure and temperature comprising kerosene; metal powder mixture of chromium powder, copper powder, lead powder, zinc powder, nickel powder, manganese powder in an amount of 12 to 13 parts by weight per 100 parts by weight of said kerosene; sulfuric acid in an amount of 15 to 30 parts by weight per 100 parts by weight of said kerosene; inorganic powder mixture of aluminum oxide powder, serpentine powder, alum powder, magnesium oxide powder, limestone powder, slake lime powder, silica powder, and granite powder in an amount of 150 to 170 parts by weight per 100 parts by weight of said kerosene.

  1. Molecular water oxidation catalyst

    DOEpatents

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

    1993-01-01

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

  2. Novel Reforming Catalysts

    SciTech Connect

    Pfefferle, Lisa D; Haller, Gary L

    2012-10-16

    Aqueous phase reforming is useful for processing oxygenated hydrocarbons to hydrogen and other more useful products. Current processing is hampered by the fact that oxide based catalysts are not stable under high temperature hydrothermal conditions. Silica in the form of structured MCM-41 is thermally a more stable support for Co and Ni than conventional high surface area amorphous silica but hydrothermal stability is not demonstrated. Carbon nanotube supports, in contrast, are highly stable under hydrothermal reaction conditions. In this project we show that carbon nanotubes are stable high activity/selectivity supports for the conversion of ethylene glycol to hydrogen.

  3. New catalysts with unsymmetrical N-heterocyclic carbene ligands.

    PubMed

    Tornatzky, Johanna; Kannenberg, Axel; Blechert, Siegfried

    2012-07-21

    The importance of unsymmetrical N-heterocyclic carbenes (uNHCs) as ligands in metal-catalyzed reactions is undeniable. While uNHCs show similar properties as compared with symmetrical NHCs, dissymmetrization allows for further fine-tuning. The introduction of chelatization, hemilability, bifunctionality, shielding effects, and chirality-transfer influences the catalyst's stability, reactivity, and selectivity, thus offering access to tailor-made systems including mono- and multidentate uNHC ligands. Based on selected examples, the structure-reactivity relationship of uNHCs employed in metal catalysts is presented. The focus is on catalytically active complexes, which either offer access to new applications or lead to significantly improved results in metal-catalyzed reactions. PMID:22584913

  4. Imaging of Oxygen Diffusion in Individual Platinum/Ce2 Zr2 Ox Catalyst Particles During Oxygen Storage and Release.

    PubMed

    Matsui, Hirosuke; Ishiguro, Nozomu; Enomoto, Kaori; Sekizawa, Oki; Uruga, Tomoya; Tada, Mizuki

    2016-09-19

    The spatial distribution of Ce(3+) and Ce(4+) in each particle of Ce2 Zr2 Ox in a three-way conversion catalyst system was successfully imaged during an oxygen storage/release cycle by scanning X-ray absorption fine structure (XAFS) using hard X-ray nanobeams. For the first time, nano-XAFS imaging visualized and identified the modes of non-uniform oxygen diffusion from the interface of Pt catalyst and Ce2 Zr2 Ox support and the active parts in individual catalyst particles. PMID:27574097

  5. A high performance Ru-ZrO2/carbon nanotubes-Ni foam composite catalyst for selective CO methanation

    NASA Astrophysics Data System (ADS)

    Xiong, Jun; Dong, Xinfa; Song, Yibing; Dong, Yingchao

    2013-11-01

    A novel Ru-ZrO2/carbon nanotubes (CNTs)-Ni foam composite catalyst for selective CO methanation is prepared by using CNTs-Ni foam as support. This catalyst exhibits an improved performance of CO selectivity and excellent catalytic stability, which may be attributed to the high thermal conductivity and unique microstructure of the Ru-based CNTs-Ni foam composite. The SEM and XRD measurements reveal that amorphous Ru-ZrO2 particles with fine size (<20 nm) are well dispersed on the CNTs surface of the composite catalyst reduced at 350 °C, possibly leading to its high catalytic activity.

  6. Darwinism Then and Now: The Divide Over Form and Function

    NASA Astrophysics Data System (ADS)

    Ruse, Michael

    2010-05-01

    As biologists have recognized since Aristotle, there are two complementary ways of looking at organisms: one can think of them from the viewpoint of homology, asking about the isomorphisms between different organisms and even within the organisms themselves; or one can think of them from the viewpoint of adaptation or final cause, asking about the ends that the features serve. I look at this divide with special respect to the theory of evolution through natural selection as first announced by the English naturalist Charles Darwin in his Origin of Species in 1859, considering both different interpretations that scholars today make of Darwin’s work and the overall implications of Darwin’s achievements for the homology/adaptation, often called the ‘form/function,’ divide.

  7. Design and analysis of unequal split Bagley power dividers

    NASA Astrophysics Data System (ADS)

    Abu-Alnadi, Omar; Dib, Nihad; Al-Shamaileh, Khair; Sheta, Abdelfattah

    2015-03-01

    In this article, we propose a general design procedure to develop unequal split Bagley power dividers (BPDs). Based on the mathematical approach carried out in the insight of simple circuit and transmission line theories, exact design equations for 3-way and 5-way BPDs are derived. Utilising the developed equations leads to power dividers with the ability of offering different output power ratios through a suitable choice of the characteristic impedances of the interconnecting transmission lines. For verification purposes, a 1:2:1 3-way, 1:2:1:2:1 5-way and 1:3:1:3:1 5-way BPDs are designed and fabricated. The experimental and full-wave simulation results prove the validity of the designed unequal split BPDs.

  8. The effect of divided attention on inhibiting the gravity error.

    PubMed

    Hood, Bruce M; Wilson, Alice; Dyson, Sally

    2006-05-01

    Children who could overcome the gravity error on Hood's (1995) tubes task were tested in a condition where they had to monitor two falling balls. This condition significantly impaired search performance with the majority of mistakes being gravity errors. In a second experiment, the effect of monitoring two balls was compared in the tubes task and a spatial transposition task not involving gravity. Again, monitoring two objects produced impaired search performance in the gravity task but not in the spatial transposition task. These findings support the view that divided attention disrupts the ability to exercise inhibitory control over the gravity error and that the performance drop on this task is not due to the additional task demands incurred by divided attention.

  9. Successfully cope with FCC catalyst

    SciTech Connect

    Lindstrom, T.H.; Hashemi, R.

    1993-08-01

    The fluid catalytic cracking (FCC) process converts straight-run atmospheric gas oil, vacuum gas oils, certain atmospheric residues, and heavy stocks recovered from other operations into high-octane gasoline, light fuel oils, and olefin-rich light gases. The main features of the FCC processes are long-term reliability and operating adjustability, allowing the refinery to easily adapt their product yields to an ever changing market. The produced gasoline, for example, has an excellent front-end octane number and good overall octane characteristics. The cracking reactions are carried out in a vertical reactor vessel in which vaporized oil rises and carries along with it in intimate contact small fluidized catalyst particles. The reactions are very rapid, and a contact time of only a few seconds is enough for most applications. During the cracking a carbonaceous material of low hydrogen-to-carbon ratio, coke, forms and deposits on the catalyst. The coke blocks the access to the internal structure of the catalyst particle and thus reduces its activity. The spent catalyst is separated from the cracking products in a catalyst stripper/disengager, and the catalyst is transported to a separate vessel, the regenerator, where the coke is burned off reactivating the catalyst. The regenerated catalyst is then transported to the bottom of the reactor riser, where the cycle begins again.

  10. Doped palladium containing oxidation catalysts

    DOEpatents

    Mohajeri, Nahid

    2014-02-18

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

  11. Transition metal sulfide loaded catalyst

    DOEpatents

    Maroni, V.A.; Iton, L.E.; Pasterczyk, J.W.; Winterer, M.; Krause, T.R.

    1994-04-26

    A zeolite-based catalyst is described for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C[sub 2]+ hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

  12. Transition metal sulfide loaded catalyst

    DOEpatents

    Maroni, Victor A.; Iton, Lennox E.; Pasterczyk, James W.; Winterer, Markus; Krause, Theodore R.

    1994-01-01

    A zeolite based catalyst for activation and conversion of methane. A zeolite support includes a transition metal (Mo, Cr or W) sulfide disposed within the micropores of the zeolite. The catalyst allows activation and conversion of methane to C.sub.2 + hydrocarbons in a reducing atmosphere, thereby avoiding formation of oxides of carbon.

  13. Catalysts for low temperature oxidation

    DOEpatents

    Toops, Todd J.; Parks, III, James E.; Bauer, John C.

    2016-03-01

    The invention provides a composite catalyst containing a first component and a second component. The first component contains nanosized gold particles. The second component contains nanosized platinum group metals. The composite catalyst is useful for catalyzing the oxidation of carbon monoxide, hydrocarbons, oxides of nitrogen, and other pollutants at low temperatures.

  14. Measuring the Digital Divide with PingER

    SciTech Connect

    Cottrell, L.

    2003-10-01

    We introduce the PingER project/toolkit and show its relevance to monitoring sites in developing countries. We then show results from PingER that illustrate the extent of the Digital Divide in terms of Internet performance between developed and developing regions, which developing regions are catching up, keeping up, or falling behind and the magnitude of the differences in performance between developed regions and developing regions.

  15. Geothermal resources of the Washakie and Great Divide basins, Wyoming

    SciTech Connect

    Heasler, H.P.; Buelow, K.L.

    1985-01-01

    The geothermal resources of the Great Divide and Washakie Basins of southern Wyoming are described. Oil well bottomhole temperatures, thermal logs of wells, and heat flow data were interpreted within a framework of geologic and hydrologic constraints. It was concluded large areas in Wyoming are underlain by water hotter than 120{sup 0}F. Isolated areas with high temperature gradients exist within each basin. 68 refs., 8 figs., 7 tabs. (ACR)

  16. Divided loyalties in medicine: the ambivalence of occupational medical practice.

    PubMed

    Walsh, D C

    1986-01-01

    This paper develops two divergent views of occupational medicine. The first holds that the field has a major contribution to make in the prevention of disease and the stabilization of health care costs. The second sees in it all the worst characteristics of contemporary medical practice. Consideration of the special difficulties of occupational physicians raises fundamental questions about the divided loyalties and moral conflicts that will increasingly beset the general practice of medicine as bureaucratic forms and controls continue to proliferate.

  17. Use of previously divided latissimus dorsi muscle for bronchopleural fistula.

    PubMed

    Kaplan, Tevfik; Kaya, Basar; Kazbek, Baturay Kansu; Kocer, Bulent; Han, Serdar; Yormuk, Erdem

    2015-06-01

    Management of postpneumonectomy bronchopleural fistula remains a major challenge for thoracic surgeons. Successful closure of a postpneumonectomy bronchopleural fistula was performed in a 60-year-old man, using a flap made by a combination of serratus anterior and latissimus dorsi muscle which had been divided during the pneumonectomy operation. The flap was prepared on the presence of a dependable collateral serratus anterior branch to the lateral thoracic artery, which provides retrograde flow to the latissimus dorsi muscle.

  18. Catalysts for hydrocarbon oxidation

    SciTech Connect

    Ott, K.C.; Paffett, M.T.; Earl, W.L.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The focus of this project was elucidating structural aspects of a titanosilicate TS-1 that is an oxidation catalyst. The authors have prepared samples of TS-1 and used scanning electron microscopy, high resolution transmission electron microscopy, and ultraviolet-visible spectroscopy to examine the samples of TS-1 for amorphous titanium-containing phases that may confound the analysis of the neutron scattering data. They observed that the volume fraction of titanium-containing impurity phases(s) determined from electron microscopy did not correlate well with that amount determined by ultraviolet-visible diffuse-reflectance spectroscopy. The authors also designed, constructed and tested a flow reactor that can be placed into the neutron flight path at the High Intensity Powder Diffractometer line at the Manual Lujan, Jr. Neutron Scattering Center. This reactor will allow for the observation of crystallographic changes of catalysts and other materials under reaction conditions.

  19. Hydrogenation of succinic acid to 1,4-butanediol over rhenium catalyst supported on copper-containing mesoporous carbon.

    PubMed

    Hong, Ung Gi; Park, Hai Woong; Lee, Joongwon; Hwang, Sunhwan; Kwak, Jimin; Yi, Jongheop; Song, In Kyu

    2013-11-01

    Copper-containing mesoporous carbon (Cu-MC) was prepared by a single-step surfactant-templating method. For comparison, copper-impregnated mesoporous carbon (Cu/MC) was also prepared by a surfactant-templating method and a subsequent impregnation method. Rhenium catalysts supported on copper-containing mesoporous carbon and copper-impregnated mesoporous carbon (Re/Cu-MC and Re/Cu/MC, respectively) were then prepared by an incipient wetness method, and they were applied to the liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO). It was observed that copper in the Re/Cu-MC catalyst was well incorporated into carbon framework, resulting in higher surface area and larger pore volume than those of Re/Cu/MC catalyst. Therefore, Re/Cu-MC catalyst showed higher copper dispersion than Re/Cu/MC catalyst, although both catalysts retained the same amounts of copper and rhenium. In the liquid-phase hydrogenation of succinic acid to BDO, Re/Cu-MC catalyst showed a better catalytic activity than Re/Cu/MC catalyst. Fine dispersion of copper in the Re/Cu-MC catalyst was responsible for its enhanced catalytic activity. PMID:24245272

  20. Hydrogenation of succinic acid to 1,4-butanediol over rhenium catalyst supported on copper-containing mesoporous carbon.

    PubMed

    Hong, Ung Gi; Park, Hai Woong; Lee, Joongwon; Hwang, Sunhwan; Kwak, Jimin; Yi, Jongheop; Song, In Kyu

    2013-11-01

    Copper-containing mesoporous carbon (Cu-MC) was prepared by a single-step surfactant-templating method. For comparison, copper-impregnated mesoporous carbon (Cu/MC) was also prepared by a surfactant-templating method and a subsequent impregnation method. Rhenium catalysts supported on copper-containing mesoporous carbon and copper-impregnated mesoporous carbon (Re/Cu-MC and Re/Cu/MC, respectively) were then prepared by an incipient wetness method, and they were applied to the liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO). It was observed that copper in the Re/Cu-MC catalyst was well incorporated into carbon framework, resulting in higher surface area and larger pore volume than those of Re/Cu/MC catalyst. Therefore, Re/Cu-MC catalyst showed higher copper dispersion than Re/Cu/MC catalyst, although both catalysts retained the same amounts of copper and rhenium. In the liquid-phase hydrogenation of succinic acid to BDO, Re/Cu-MC catalyst showed a better catalytic activity than Re/Cu/MC catalyst. Fine dispersion of copper in the Re/Cu-MC catalyst was responsible for its enhanced catalytic activity.

  1. How Does a Divided Population Respond to Change?

    PubMed Central

    Qubbaj, Murad R.; Muneepeerakul, Rachata; Aggarwal, Rimjhim M.; Anderies, John M.

    2015-01-01

    Most studies on the response of socioeconomic systems to a sudden shift focus on long-term equilibria or end points. Such narrow focus forgoes many valuable insights. Here we examine the transient dynamics of regime shift on a divided population, exemplified by societies divided ideologically, politically, economically, or technologically. Replicator dynamics is used to investigate the complex transient dynamics of the population response. Though simple, our modeling approach exhibits a surprisingly rich and diverse array of dynamics. Our results highlight the critical roles played by diversity in strategies and the magnitude of the shift. Importantly, it allows for a variety of strategies to arise organically as an integral part of the transient dynamics—as opposed to an independent process—of population response to a regime shift, providing a link between the population's past and future diversity patterns. Several combinations of different populations' strategy distributions and shifts were systematically investigated. Such rich dynamics highlight the challenges of anticipating the response of a divided population to a change. The findings in this paper can potentially improve our understanding of a wide range of socio-ecological and technological transitions. PMID:26161859

  2. How Does a Divided Population Respond to Change?

    PubMed

    Qubbaj, Murad R; Muneepeerakul, Rachata; Aggarwal, Rimjhim M; Anderies, John M

    2015-01-01

    Most studies on the response of socioeconomic systems to a sudden shift focus on long-term equilibria or end points. Such narrow focus forgoes many valuable insights. Here we examine the transient dynamics of regime shift on a divided population, exemplified by societies divided ideologically, politically, economically, or technologically. Replicator dynamics is used to investigate the complex transient dynamics of the population response. Though simple, our modeling approach exhibits a surprisingly rich and diverse array of dynamics. Our results highlight the critical roles played by diversity in strategies and the magnitude of the shift. Importantly, it allows for a variety of strategies to arise organically as an integral part of the transient dynamics--as opposed to an independent process--of population response to a regime shift, providing a link between the population's past and future diversity patterns. Several combinations of different populations' strategy distributions and shifts were systematically investigated. Such rich dynamics highlight the challenges of anticipating the response of a divided population to a change. The findings in this paper can potentially improve our understanding of a wide range of socio-ecological and technological transitions.

  3. Fine Shades of a Sombrero

    NASA Astrophysics Data System (ADS)

    2000-02-01

    In addition to their scientific value, many of the exposures now being obtained by visiting astronomers to ESO's Very Large Telescope (VLT) are also very beautiful. This is certainly true for this new image of the famous early-type spiral galaxy Messier 104 , widely known as the "Sombrero" (the Mexican hat) because of its particular shape. The colour image was made by a combination of three CCD images from the FORS1 multi-mode instrument on VLT ANTU , recently obtained by Peter Barthel from the Kapteyn Institute (Groningen, The Netherlands) during an observing run at the Paranal Observatory. He and Mark Neeser , also from the Kapteyn Institute, produced the composite images. The galaxy fits perfectly into the 6.8 x 6.8 arcmin 2 field-of-view of the FORS1 camera. A great amount of fine detail is revealed, from the structures in the pronounced dust band in the equatorial plane, to many faint background galaxies that shine through the outer regions. The "Sombrero" is located in the constellation Virgo (The Virgin), at a distance of about 50 million light-years. The overall "sharpness" of this colour image corresponds to about 0.7 arcsec which translates into a resolution of about 170 light-years at that distance. About Messier 104 Messier 104 is the 104th object in the famous catalogue of nebulae by French astronomer Charles Messier (1730 - 1817). It was not included in the first two editions (with 45 objects in 1774; 103 in 1781), but Messier soon thereafter added it by hand in his personal copy as a "very faint nebula". The recession velocity, about 1000 km/sec, was first measured by American astronomer Vesto M. Slipher at the Lowell Observatory in 1912; he was also the first to detect the galaxy's rotation. ESO Press Photo 07c/00 ESO Press Photo 07c/00 [Preview; JPEG: 400 x 307; 59k] [Normal; JPEG: 800 x 614; 308k] [Full-Res; JPEG: 2028 x 1556; 2.3Mb] PR Photo 07c/00 has been processed to show the numerous dust bands in the central plane of the Sombrero galaxy (see

  4. Catalysts Encapsulated in Molecular Machines.

    PubMed

    Pan, Tiezheng; Liu, Junqiu

    2016-06-17

    Smart catalysts offer the control of chemical processes and sequences of transformations, and catalysts with unique catalytic behavior can afford chiral products or promote successive polymerization. To meet advanced demands, the key to constructing smart catalysts is to incorporate traditional catalytic functional groups with trigger-induced factors. Molecular machines with dynamic properties and particular topological structures have typical stimulus-responsive features. In recent years, scientists have made efforts to utilize molecular machines (molecular switches, rotaxanes, motors, etc.) as scaffolds to develop smart catalysts. This Minireview focuses on the achievements of developing catalysts encapsulated in molecular machines and their remarkable specialties. This strategy is believed to provide more potential applications in switchable reactions, asymmetric synthesis, and processive catalysis.

  5. HDS catalysts performance and properties

    SciTech Connect

    Panarello, F.; Guanziroli, S.

    1995-12-31

    The European refiners are being asked to produce cleaner diesel fuel which might reduce engine emissions. To meet this requirement they have to increase the hydrotreatment capacity and to use the best catalysts in terms of activity and deactivation performances. In particular, Co-Mo on gamma-alumina catalysts are currently in use to reduce diesel sulfur content. In the past, different chemical-physical modifications have been studied in order to improve the catalysts performances, many theoretical correlations between one or more chemical-physical properties and activity have been suggested. We tested different Co-Mo catalysts in pilot plant units with various refinery streams and run length up to two thousand hours. We performed on fresh, exhausted and regenerated catalysts samples, elemental composition, surface properties, metal dispersion and metal distribution analyses. Among the various chemical-physical properties the metal distribution is the parameter that correlates in the most satisfactory way with the catalytic performances.

  6. Process for preparing fine grain titanium carbide powder

    DOEpatents

    Janey, Mark A.

    1986-01-01

    A method for preparing finely divided titanium carbide powder in which an organotitanate is reacted with a carbon precursor polymer to provide an admixture of the titanium and the polymer at a molecular-level due to a crosslinking reaction between the organotitanate and the polymer. The resulting gel is dried, pyrolyzed to drive off volatile components and provide carbon. The resulting solids are then heated at an elevated temperature to convert the titanium and carbon to high-purity titanium carbide powder in a submicron size range.

  7. Process for preparing fine grain silicon carbide powder

    DOEpatents

    Wei, G.C.

    Finely divided silicon carbide powder is obtained by mixing colloidal silica and unreacted phenolic resin in either acetone or methanol, evaporating solvent from the obtained solution to form a gel, drying and calcining the gel to polymerize the phenolic resin therein, pyrolyzing the dried and calcined gel at a temperature in the range of 500 to 1000/sup 0/C, and reacting silicon and carbon in the pyrolyzed gel at a temperature in the range of 1550 to 1700/sup 0/C to form the powder.

  8. Process for preparing fine grain titanium carbide powder

    DOEpatents

    Janney, M.A.

    1985-03-12

    A method for preparing finely divided titanium carbide powder in which an organotitanate is reacted with a carbon precursor polymer to provide an admixture of the titanium and the polymer at a molecular level due to a crosslinking reaction between the organotitanate and the polymer. The resulting gel is dried, pyrolyzed to drive off volatile components and provide carbon. The resulting solids are then heated at an elevated temperature to convert the titanium and carbon to high-purity titanium carbide powder in a submicron size range.

  9. Compressive behavior of fine sand.

    SciTech Connect

    Martin, Bradley E.; Kabir, Md. E.; Song, Bo; Chen, Wayne

    2010-04-01

    The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.

  10. Wetter for fine dry powder

    DOEpatents

    Hall, James E.; Williams, Everett H.

    1977-01-01

    A system for wetting fine dry powders such as bentonite clay with water or other liquids is described. The system includes a wetting tank for receiving water and a continuous flow of fine powder feed. The wetting tank has a generally square horizontal cross section with a bottom end closure in the shape of an inverted pyramid. Positioned centrally within the wetting tank is a flow control cylinder which is supported from the walls of the wetting tank by means of radially extending inclined baffles. A variable speed motor drives a first larger propeller positioned immediately below the flow control cylinder in a direction which forces liquid filling the tank to flow downward through the flow control cylinder and a second smaller propeller positioned below the larger propeller having a reverse pitch to oppose the flow of liquid being driven downward by the larger propeller.

  11. Dense, finely, grained composite materials

    DOEpatents

    Dunmead, Stephen D.; Holt, Joseph B.; Kingman, Donald D.; Munir, Zuhair A.

    1990-01-01

    Dense, finely grained composite materials comprising one or more ceramic phase or phase and one or more metallic and/or intermetallic phase or phases are produced by combustion synthesis. Spherical ceramic grains are homogeneously dispersed within the matrix. Methods are provided, which include the step of applying mechanical pressure during or immediately after ignition, by which the microstructures in the resulting composites can be controllably selected.

  12. Electrochemical Process Makes Fine Needles

    NASA Technical Reports Server (NTRS)

    Watkins, J. L.

    1986-01-01

    Electrochemical process makes fine tungsten needles for use as microscopic probes or field-emission cathodes. Etching vessel filled with dense, inert lower liquid covered by less-dense, caustic etching solution. Newly formed needle breaks off upper part of wire in etchant and falls into can in inert liquid below. Improved process does not require close monitoring and left unattended for an indefinite time.

  13. Chemical composition of emissions from urban sources of fine organic aerosol

    SciTech Connect

    Hildemann, L.M.; Markowski, G.R.; Cass, G.R. )

    1991-04-01

    A dilution source sampling system was used to collect primary fine aerosol emissions from important sources of urban organic aerosol, including a boiler burning No. 2 fuel oil, a home fireplace, a fleet of catalyst-equipped and noncatalyst automobiles, heavy-duty diesel trucks, natural gas home appliances, and meat cooking operations. Alternative dilution sampling techniques were used to collect emissions from cigarette smoking and a roofing tar pot, and grab sample techniques were employed to characterize paved road dust, brake lining wear, and vegetative detritus. Organic aerosol constituted the majority of the fine aerosol mass emitted from many of the sources tested. Fine primary organic aerosol emissions within the heavily urbanized western portion of the Los Angeles Basin were determined to total 29.8 metric ton/day. Over 40% of these organic aerosol emissions are from anthropogenic pollution sources that are expected to emit contemporary (nonfossil) aerosol carbon, in good agreement with the available ambient monitoring data.

  14. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, John E.; Herzog, Timothy A.

    1998-01-01

    A metallocene catalyst system for the polymerization of .alpha.-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula ##STR1## wherein: R.sup.1, R.sup.2, and R.sup.3 are independently selected from the group consisting of hydrogen, C.sub.1 to C.sub.10 alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C.sub.1 to C.sub.10 alkyls as a substituent, C.sub.6 to C.sub.15 aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R.sup.8).sub.3 where R.sup.8 is selected from the group consisting of C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; R.sup.4 and R.sup.6 are substituents both having van der Waals radii larger than the van der Waals radii of groups R.sup.1 and R.sup.3 ; R.sup.5 is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E.sup.1, E.sup.2 are independently selected from the group consisting of Si(R.sup.9).sub.2, Si(R.sup.9).sub.2 --Si(R.sup.9).sub.2, Ge(R.sup.9).sub.2, Sn(R.sup.9).sub.2, C(R.sup.9).sub.2, C(R.sup.9).sub.2 --C(R.sup.9).sub.2, where R.sup.9 is C.sub.1 to C.sub.10 alkyl, C.sub.6 to C.sub.15 aryl or C.sub.3 to C.sub.10 cycloalkyl; and the ligand may have C.sub.S or C.sub.1 -symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from .alpha.-olefin monomers.

  15. Stereospecific olefin polymerization catalysts

    DOEpatents

    Bercaw, J.E.; Herzog, T.A.

    1998-01-13

    A metallocene catalyst system is described for the polymerization of {alpha}-olefins to yield stereospecific polymers including syndiotactic, and isotactic polymers. The catalyst system includes a metal and a ligand of the formula shown wherein: R{sup 1}, R{sup 2}, and R{sup 3} are independently selected from the group consisting of hydrogen, C{sub 1} to C{sub 10} alkyl, 5 to 7 membered cycloalkyl, which in turn may have from 1 to 3 C{sub 1} to C{sub 10} alkyls as a substituent, C{sub 6} to C{sub 15} aryl or arylalkyl in which two adjacent radicals may together stand for cyclic groups having 4 to 15 carbon atoms which in turn may be substituted, or Si(R{sup 8}){sub 3} where R{sup 8} is selected from the group consisting of C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; R{sup 4} and R{sup 6} are substituents both having van der Waals radii larger than the van der Waals radii of groups R{sup 1} and R{sup 3}; R{sup 5} is a substituent having a van der Waals radius less than about the van der Waals radius of a methyl group; E{sup 1}, E{sup 2} are independently selected from the group consisting of Si(R{sup 9}){sub 2}, Si(R{sup 9}){sub 2}--Si(R{sup 9}){sub 2}, Ge(R{sup 9}){sub 2}, Sn(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}, C(R{sup 9}){sub 2}--C(R{sup 9}){sub 2}, where R{sup 9} is C{sub 1} to C{sub 10} alkyl, C{sub 6} to C{sub 15} aryl or C{sub 3} to C{sub 10} cycloalkyl; and the ligand may have C{sub S} or C{sub 1}-symmetry. Preferred metals are selected from the group consisting of group III, group IV, group V or lanthanide group elements. The catalysts are used to prepare stereoregular polymers including polypropylene from {alpha}-olefin monomers.

  16. Generic Divide and Conquer Internet-Based Computing

    NASA Technical Reports Server (NTRS)

    Radenski, Atanas; Follen, Gregory J. (Technical Monitor)

    2001-01-01

    The rapid growth of internet-based applications and the proliferation of networking technologies have been transforming traditional commercial application areas as well as computer and computational sciences and engineering. This growth stimulates the exploration of new, internet-oriented software technologies that can open new research and application opportunities not only for the commercial world, but also for the scientific and high -performance computing applications community. The general goal of this research project is to contribute to better understanding of the transition to internet-based high -performance computing and to develop solutions for some of the difficulties of this transition. More specifically, our goal is to design an architecture for generic divide and conquer internet-based computing, to develop a portable implementation of this architecture, to create an example library of high-performance divide-and-conquer computing agents that run on top of this architecture, and to evaluate the performance of these agents. We have been designing an architecture that incorporates a master task-pool server and utilizes satellite computational servers that operate on the Internet in a dynamically changing large configuration of lower-end nodes provided by volunteer contributors. Our designed architecture is intended to be complementary to and accessible from computational grids such as Globus, Legion, and Condor. Grids provide remote access to existing high-end computing resources; in contrast, our goal is to utilize idle processor time of lower-end internet nodes. Our project is focused on a generic divide-and-conquer paradigm and its applications that operate on a loose and ever changing pool of lower-end internet nodes.

  17. Surface Tension and Adsorption without a Dividing Surface.

    PubMed

    Marmur, Abraham

    2015-11-24

    The ingenious concept of a dividing surface of zero thickness that was introduced by Gibbs is the basis of the theory of surface tension and adsorption. However, some fundamental questions, mainly those related to the location of the dividing surface and the proper definition of relative adsorption, have remained open over the years. To avoid these questions, the present paper proposes to analyze an interfacial phase by defining a thermodynamic system of constant, but nonzero thickness. The interfacial phase is analyzed as it really is, namely a nonuniform three-dimensional entity. The current analysis redevelops the equation for calculating surface tension, though with different assumptions. However, the main point in the proposed model is that the thermodynamic interfacial system, due to its fixed thickness, conforms to the requirement of first-order homogeneity of the internal energy. This property is the key that allows using the Gibbs adsorption isotherm. It is also characteristic of the Gibbs dividing surface model, but has not always been discussed with regard to subsequent models. The resulting equation leads to a simple, "natural" expression for the relative adsorption. This expression may be compared with simulations and sophisticated surface concentration measurements, and from which the dependence of interfacial tension on the solution composition can be derived. Finally, it is important to point out that in order to calculate the interfacial tension as well as the relative adsorption from data on the properties of the interfacial phase, there is no need to know its exact thickness, as long as it is bigger than the actual thickness but sufficiently small.

  18. Catalyst deactivation in residue hydrocracking

    SciTech Connect

    Oballa, M.C.; Wong, C.; Krzywicki, A.

    1994-12-31

    The existence of a computer-controlled bench scale hydrocracking units at the authors site has made cheaper the non-stop running of experiments for long periods of time. It was, therefore possible to show, at minimal costs, when three hydrocracking catalysts in service reach their maximum lifetime. Different parameters which are helpful for catalyst life and activity predictions were calculated, e.g., relative catalyst age and the effectiveness factor. Experimental results compared well with model, giving them the minimum and maximum catalyst lifetime, as well as the deactivation profile with regard to sulfur and metals removal. Reaction rate constants for demetallization and desulfurization were also determined. Six commercial catalysts were evaluated at short term runs and the three most active were used for long term runs. Out of three catalysts tested for deactivation at long term runs, it was possible to choose one whose useful life was higher than the others. All runs were carried out in a Robinson-Mahoney continuous flow stirred tank reactor, using 50/50 volumetric mixture of Cold Lake/Lloydminster atmospheric residue and NiMo/Al{sub 2}O{sub 3} catalyst.

  19. Catalysts for a cleaner environment

    SciTech Connect

    1995-09-01

    Pollution-abatement catalysts remain a challenging area for process development. That`s because the pollutants themselves often poison the catalysts, and the new catalytic processes are now required to capture pollutants from very dilute waste streams. A case in point in the US is how severely low-level emissions of halogenated hydrocarbons are regulated through Title III regulations on toxic compounds. While common oxidation catalysts may be quite effective at eliminating most VOC [volatile organic compound] emissions, the presence of halogenated hydrocarbons can adversely affect catalyst performance. Only recently have catalysts become available that will be effective at oxidizing the halogenated hydrocarbons. The items described below illustrate the variety and scope of recently introduced catalysts that have proved themselves by increasing yields and reducing emissions. The offerings include catalysts for: improving yield in the production of acrylic acid, ammonia, styrene, phthalic anhydride and alcohol; reducing the sulfur and aromatic content of fuels; curtailing byproduct production in fluid-catalytic cracking units; oxidizing emissions of chlorinated hydrocarbons; and reducing NOx in combustion gas using hydrogen or carbon monoxide.

  20. Pump tank divider plate for sump suction sodium pumps

    DOEpatents

    George, John A.; Nixon, Donald R.

    1977-01-01

    A circular plate extends across the diameter of "sump suction" pump, with a close clearance between the edge of the plate and the wall of the pump tank. The plate is located above the pump impeller, inlet and outlet flow nozzles but below the sodium free surface and effectively divides the pump tank into two separate chambers. On change of pump speed, the close fitting flow restriction plate limits the rate of flow into or out of the upper chamber, thereby minimizing the rate of level change in the tank and permitting time for the pump cover gas pressure to be varied to maintain an essentially constant level.

  1. Divided-pulse amplification to the joule level.

    PubMed

    Webb, Benjamin; Azim, Ahmad; Bodnar, Nathan; Chini, Michael; Shah, Lawrence; Richardson, Martin

    2016-07-01

    Divided-pulse amplification (DPA) has proven to be a valuable tool in scaling the peak power of diode-pumped ytterbium-doped amplifiers to beyond the single-pulse threshold for parasitic nonlinear effects. DPA enables the amplification of picosecond pulses in solid-state amplifiers with limited bandwidth beyond the single-pulse damage threshold. In this Letter, we demonstrate DPA of picosecond pulses in a flashlamp-pumped Nd:YAG amplifier for the first time, to the best of our knowledge, yielding a combined pulse energy of 167 mJ. PMID:27367113

  2. Transition duct with divided upstream and downstream portions

    SciTech Connect

    McMahan, Kevin Weston; LeBegue, Jeffrey Scott; Maldonado, Jaime Javier; Dillard, Daniel Jackson; Flanagan, James Scott

    2015-07-14

    Turbine systems are provided. In one embodiment, a turbine system includes a transition duct comprising an inlet, an outlet, and a duct passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The duct passage includes an upstream portion extending from the inlet and a downstream portion extending from the outlet. The turbine system further includes a rib extending from an outer surface of the duct passage, the rib dividing the upstream portion and the downstream portion.

  3. Wideband resistive voltage divider for a standard wattmeter

    NASA Astrophysics Data System (ADS)

    Slomovitz, D.; Trigo, L.; Aristoy, G.; Brehm, M.; Kyriazis, G. A.

    2016-07-01

    This work shows the state of development of resistive voltage dividers for use in a standard wattmeter that covers a frequency range from 50 Hz to 100 kHz. The voltage ranges go from 4 V to 1024 V with an expected accuracy of 20 μV/V and 60 μrad/kHz. Nonlinear influences are studied and different methods to compensate the effect of stray capacitances are analysed, as well as the measurement systems used to calibrate these devices.

  4. Ceramic catalyst materials

    SciTech Connect

    Sault, A.G.; Gardner, T.J.; Hanprasopwattanna, A.; Reardon, J.; Datye, A.K.

    1995-08-01

    Hydrous titanium oxide (HTO) ion-exchange materials show great potential as ceramic catalyst supports due to an inherently high ion-exchange capacity which allows facile loading of catalytically active transition metal ions, and an ability to be cast as thin films on virtually any substrate. By coating titania and HTO materials onto inexpensive, high surface area substrates such as silica and alumina, the economics of using these materials is greatly improved, particularly for the HTO materials, which are substantially more expensive in the bulk form than other oxide supports. In addition, the development of thin film forms of these materials allows the catalytic and mechanical properties of the final catalyst formulation to be separately engineered. In order to fully realize the potential of thin film forms of titania and HTO, improved methods for the deposition and characterization of titania and HTO films on high surface area substrates are being developed. By varying deposition procedures, titania film thickness and substrate coverage can be varied from the submonolayer range to multilayer thicknesses on both silica and alumina. HTO films can also be formed, but the quality and reproducibility of these films is not nearly as good as for pure titania films. The films are characterized using a combination of isopropanol dehydration rate measurements, point of zero charge (PZC) measurements, BET surface area, transmission electron microscopy (TEM), and elemental analysis. In order to assess the effects of changes in film morphology on catalytic activity, the films are being loaded with MoO{sub 3} using either incipient wetness impregnation or ion-exchange of heptamolybdate anions followed by calcining. The MoO{sub 3} is then sulfided to form MOS{sub 2}, and tested for catalytic activity using pyrene hydrogenation and dibenzothiophene (DBT) desulfurization, model reactions that simulate reactions occurring during coal liquefaction.

  5. Considering Fine Art and Picture Books

    ERIC Educational Resources Information Center

    Serafini, Frank

    2015-01-01

    There has been a close association between picturebook illustrations and works of fine art since the picturebook was first conceived, and many ways these associations among works of fine art and picturebook illustrations and design play out. To make sense of all the various ways picturebook illustrations are associated with works of fine art,…

  6. 36 CFR 910.35 - Fine arts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Fine arts. 910.35 Section 910... DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.35 Fine arts. Fine arts... of art which are appropriate for the development. For information and guidance, a...

  7. 36 CFR 910.35 - Fine arts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Fine arts. 910.35 Section 910... DEVELOPMENT AREA Standards Uniformly Applicable to the Development Area § 910.35 Fine arts. Fine arts... of art which are appropriate for the development. For information and guidance, a...

  8. Green chemistry: biodiesel made with sugar catalyst.

    PubMed

    Toda, Masakazu; Takagaki, Atsushi; Okamura, Mai; Kondo, Junko N; Hayashi, Shigenobu; Domen, Kazunari; Hara, Michikazu

    2005-11-10

    The production of diesel from vegetable oil calls for an efficient solid catalyst to make the process fully ecologically friendly. Here we describe the preparation of such a catalyst from common, inexpensive sugars. This high-performance catalyst, which consists of stable sulphonated amorphous carbon, is recyclable and its activity markedly exceeds that of other solid acid catalysts tested for 'biodiesel' production. PMID:16281026

  9. Chemical interactions in multimetal/zeolite catalysts

    SciTech Connect

    Sachtler, W.M.H.

    1992-02-07

    This report treats four subject areas: PtCu/NaY and Pd/Cu/NaY catalysts; reducibility of Ni in PdNi/NaY catalysts; CO hydrogenation over PdNi/NaY catalysts; and PdFe/NaY, Ga/H-ZSM5 and PtGa/H-ZSM5 catalysts.

  10. Chalcogen catalysts for polymer electrolyte fuel cell

    DOEpatents

    Zelenay, Piotr; Choi, Jong-Ho; Alonso-Vante, Nicolas; Wieckowski, Andrzej; Cao, Dianxue

    2010-08-24

    A methanol-tolerant cathode catalyst and a membrane electrode assembly for fuel cells that includes such a cathode catalyst. The cathode catalyst includes a support having at least one transition metal in elemental form and a chalcogen disposed on the support. Methods of making the cathode catalyst and membrane electrode assembly are also described.

  11. Chalcogen catalysts for polymer electrolyte fuel cell

    DOEpatents

    Alonso-Vante, Nicolas; Zelenay, Piotr; Choi, Jong-Ho; Wieckowski, Andrzej; Cao, Dianxue

    2009-09-15

    A methanol-tolerant cathode catalyst and a membrane electrode assembly for fuel cells that includes such a cathode catalyst. The cathode catalyst includes a support having at least one transition metal in elemental form and a chalcogen disposed on the support. Methods of making the cathode catalyst and membrane electrode assembly are also described.

  12. Green chemistry: Biodiesel made with sugar catalyst

    NASA Astrophysics Data System (ADS)

    Toda, Masakazu; Takagaki, Atsushi; Okamura, Mai; Kondo, Junko N.; Hayashi, Shigenobu; Domen, Kazunari; Hara, Michikazu

    2005-11-01

    The production of diesel from vegetable oil calls for an efficient solid catalyst to make the process fully ecologically friendly. Here we describe the preparation of such a catalyst from common, inexpensive sugars. This high-performance catalyst, which consists of stable sulphonated amorphous carbon, is recyclable and its activity markedly exceeds that of other solid acid catalysts tested for `biodiesel' production.

  13. Molecular metal catalysts on supports: organometallic chemistry meets surface science.

    PubMed

    Serna, Pedro; Gates, Bruce C

    2014-08-19

    Recent advances in the synthesis and characterization of small, essentially molecular metal complexes and metal clusters on support surfaces have brought new insights to catalysis and point the way to systematic catalyst design. We summarize recent work unraveling effects of key design variables of site-isolated catalysts: the metal, metal nuclearity, support, and other ligands on the metals, also considering catalysts with separate, complementary functions on supports. The catalysts were synthesized with the goal of structural simplicity and uniformity to facilitate incisive characterization. Thus, they are essentially molecular species bonded to porous supports chosen for their high degree of uniformity; the supports are crystalline aluminosilicates (zeolites) and MgO. The catalytic species are synthesized in reactions of organometallic precursors with the support surfaces; the precursors include M(L)2(acetylacetonate)1-2, with M = Ru, Rh, Ir, or Au and the ligands L = C2H4, CO, or CH3. Os3(CO)12 and Ir4(CO)12 are used as precursors of supported metal clusters, and some such catalysts are made by ship-in-a-bottle syntheses to trap the clusters in zeolite cages. The simplicity and uniformity of the supported catalysts facilitate precise structure determinations, even in reactive atmospheres and during catalysis. The methods of characterizing catalysts in reactive atmospheres include infrared (IR), extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and nuclear magnetic resonance (NMR) spectroscopies, and complementary methods include density functional theory and atomic-resolution aberration-corrected scanning transmission electron microscopy for imaging of individual metal atoms. IR, NMR, XANES, and microscopy data demonstrate the high degrees of uniformity of well-prepared supported species. The characterizations determine the compositions of surface metal complexes and clusters, including the ligands and the metal

  14. Molecular metal catalysts on supports: organometallic chemistry meets surface science.

    PubMed

    Serna, Pedro; Gates, Bruce C

    2014-08-19

    Recent advances in the synthesis and characterization of small, essentially molecular metal complexes and metal clusters on support surfaces have brought new insights to catalysis and point the way to systematic catalyst design. We summarize recent work unraveling effects of key design variables of site-isolated catalysts: the metal, metal nuclearity, support, and other ligands on the metals, also considering catalysts with separate, complementary functions on supports. The catalysts were synthesized with the goal of structural simplicity and uniformity to facilitate incisive characterization. Thus, they are essentially molecular species bonded to porous supports chosen for their high degree of uniformity; the supports are crystalline aluminosilicates (zeolites) and MgO. The catalytic species are synthesized in reactions of organometallic precursors with the support surfaces; the precursors include M(L)2(acetylacetonate)1-2, with M = Ru, Rh, Ir, or Au and the ligands L = C2H4, CO, or CH3. Os3(CO)12 and Ir4(CO)12 are used as precursors of supported metal clusters, and some such catalysts are made by ship-in-a-bottle syntheses to trap the clusters in zeolite cages. The simplicity and uniformity of the supported catalysts facilitate precise structure determinations, even in reactive atmospheres and during catalysis. The methods of characterizing catalysts in reactive atmospheres include infrared (IR), extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and nuclear magnetic resonance (NMR) spectroscopies, and complementary methods include density functional theory and atomic-resolution aberration-corrected scanning transmission electron microscopy for imaging of individual metal atoms. IR, NMR, XANES, and microscopy data demonstrate the high degrees of uniformity of well-prepared supported species. The characterizations determine the compositions of surface metal complexes and clusters, including the ligands and the metal

  15. Textured catalysts, methods of making textured catalysts, and methods of catalyzing reactions conducted in hydrothermal conditions

    DOEpatents

    Werpy, Todd [West Richland, WA; Wang, Yong [Richland, WA

    2003-12-30

    A textured catalyst having a hydrothermally-stable support, a metal oxide and a catalyst component is described. Methods of conducting aqueous phase reactions that are catalyzed by a textured catalyst are also described. The invention also provides methods of making textured catalysts and methods of making chemical products using a textured catalyst.

  16. A divide and conquer approach to multiple alignment.

    PubMed

    Dress, A; Füllen, G; Perrey, S

    1995-01-01

    We present a report on work in progress on a divide and conquer approach to multiple alignment. The algorithm makes use of the costs calculated from applying the standard dynamic programming scheme to all pairs of sequences. The resulting cost matrices for pairwise alignment give rise to secondary matrices containing the additional costs imposed by fixing the path through the dynamic programming graph at a particular vertex. Such a constraint corresponds to a division of the problem obtained by slicing both sequences between two particular positions, and aligning the two sequences on the left and the two sequences on the right, charging for gaps introduced at the slicing point. To obtain an estimate for the additional cost imposed by forcing the multiple alignment through a particular vertex in the whole hypercube, we will take a (weighted) sum of secondary costs over all pairwise projections of the division of the problem, as defined by this vertex, that is, by slicing all sequences at the points suggested by the vertex. We then use that partition of every single sequence under consideration into two 'halfs' which imposes a minimal (weighted) sum of pairwise additional costs, making sure that one of the sequences is divided somewhere close to its midpoint. Hence, each iteration can cut the problem size in half. As the enumeration of all possible partitions may restrict this approach to small-size problems, we eliminate futile partitions, and organize their enumeration in a way that starts with the most promising ones.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Embodied ideas and divided selves: revisiting Laing via Bakhtin.

    PubMed

    Burkitt, Ian; Sullivan, Paul

    2009-09-01

    In this article, we apply Mikhail Bakhtin's model of a 'divided self' to R.D. Laing's eponymous work on the lived experience of divided selves in 'psychosis'. Both of these authors offer intriguing insights into the fracturing of self through its social relationships (including the 'micro-dialogues' staged for oneself) but from uniquely different perspectives. Bakhtin (1984) uses Dostoevsky's novels as his material for a theory of self, centrally concerned with moments of split identity, crisis, and personal transformation, while Laing relies on his patient's accounts of 'psychosis'. We will outline how two key Bakhtinian divisions of the self (spirit/soul and authoritative/internally persuasive discourse) help to make sense of Laing's descriptions of his patient's experiences and micro-dialogues. Conversely, when refracted through Laing's phenomenology Bakhtin's account of the self becomes richer and somewhat darkened in terms of a double-edged ontology, which describes a maximally open self but one that is consumed by ideas, unable to manage their contradictions. The implications of this for managing the dilemmas of self-identity will be drawn out.

  18. Stratified Flow Past a Hill: Dividing Streamline Concept Revisited

    NASA Astrophysics Data System (ADS)

    Leo, Laura S.; Thompson, Michael Y.; Di Sabatino, Silvana; Fernando, Harindra J. S.

    2016-06-01

    The Sheppard formula (Q J R Meteorol Soc 82:528-529, 1956) for the dividing streamline height H_s assumes a uniform velocity U_∞ and a constant buoyancy frequency N for the approach flow towards a mountain of height h, and takes the form H_s/h=( {1-F} ) , where F=U_{∞}/Nh. We extend this solution to a logarithmic approach-velocity profile with constant N. An analytical solution is obtained for H_s/h in terms of Lambert-W functions, which also suggests alternative scaling for H_s/h. A `modified' logarithmic velocity profile is proposed for stably stratified atmospheric boundary-layer flows. A field experiment designed to observe H_s is described, which utilized instrumentation from the spring field campaign of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program. Multiple releases of smoke at F≈ 0.3-0.4 support the new formulation, notwithstanding the limited success of experiments due to logistical constraints. No dividing streamline is discerned for F≈ 10, since, if present, it is too close to the foothill. Flow separation and vortex shedding is observed in this case. The proposed modified logarithmic profile is in reasonable agreement with experimental observations.

  19. High Temperature Membrane & Advanced Cathode Catalyst Development

    SciTech Connect

    Protsailo, Lesia

    2006-04-20

    Current project consisted of three main phases and eighteen milestones. Short description of each phase is given below. Table 1 lists program milestones. Phase 1--High Temperature Membrane and Advanced Catalyst Development. New polymers and advanced cathode catalysts were synthesized. The membranes and the catalysts were characterized and compared against specifications that are based on DOE program requirements. The best-in-class membranes and catalysts were downselected for phase 2. Phase 2--Catalyst Coated Membrane (CCM) Fabrication and Testing. Laboratory scale catalyst coated membranes (CCMs) were fabricated and tested using the down-selected membranes and catalysts. The catalysts and high temperature membrane CCMs were tested and optimized. Phase 3--Multi-cell stack fabrication. Full-size CCMs with the down-selected and optimized high temperature membrane and catalyst were fabricated. The catalyst membrane assemblies were tested in full size cells and multi-cell stack.

  20. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    SciTech Connect

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2004-09-30

    In this reporting period, a fundamental filtration study was continued to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. The shakedown phase of the pilot-scale filtration platform was completed at the end of the last reporting period. A study of various molecular weight waxes was initiated to determine the effect of wax physical properties on the permeation rate without catalyst present. As expected, the permeation flux was inversely proportional to the nominal average molecular weight of the polyethylene wax. Even without catalyst particles present in the filtrate, the filtration membranes experience fouling during an induction period on the order of days on-line. Another long-term filtration test was initiated using a batch of iron catalyst that was previously activated with CO to form iron carbide in a separate continuous stirred tank reactor (CSTR) system. The permeation flux stabilized more rapidly than that experienced with unactivated catalyst tests.

  1. Template Effect and Ligand Substitution Methods for the Synthesis of Iron Catalysts: A Two-Part Experiment for Inorganic Chemistry

    ERIC Educational Resources Information Center

    Sues, Peter E.; Cai, Kuihua; McIntosh, Douglas F.; Morris, Robert H.

    2015-01-01

    Asymmetric transfer hydrogenation is an important transformation for the production of fine chemicals. Traditionally, platinum group metals are used to catalyze this reaction, but recent pressure for greener practices has driven the development of base-metal catalysts. Due to the growing interest in this area of research, the underlying concepts…

  2. The electron is a catalyst

    NASA Astrophysics Data System (ADS)

    Studer, Armido; Curran, Dennis P.

    2014-09-01

    The electron is an efficient catalyst for conducting various types of radical cascade reaction that proceed by way of radical and radical ion intermediates. But because electrons are omnipresent, catalysis by electrons often passes unnoticed. In this Review, a simple analogy between acid/base catalysis and redox catalysis is presented. Conceptually, the electron is a catalyst in much the same way that a proton is a catalyst. The 'electron is a catalyst' paradigm unifies mechanistically an assortment of synthetic transformations that otherwise have little or no apparent relationship. Diverse radical cascades, including unimolecular radical substitution reactions (SRN1-type chemistry), base-promoted homolytic aromatic substitutions (BHAS), radical Heck-type reactions, radical cross-dehydrogenative couplings (CDC), direct arene trifluoromethylations and radical alkoxycarbonylations, can all be viewed as electron-catalysed reactions.

  3. Catalyst for sodium chlorate decomposition

    NASA Technical Reports Server (NTRS)

    Wydeven, T.

    1972-01-01

    Production of oxygen by rapid decomposition of cobalt oxide and sodium chlorate mixture is discussed. Cobalt oxide serves as catalyst to accelerate reaction. Temperature conditions and chemical processes involved are described.

  4. Secret Lives of Catalysts Revealed

    ScienceCinema

    Miquel Salmeron and Gabor Somorjai

    2010-01-08

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-relea...

  5. Secret Lives of Catalysts Revealed

    SciTech Connect

    Miquel Salmeron and Gabor Somorjai

    2008-10-15

    Miquel Salmeron and Gabor Somorjai of Berkeley Lab's Materials Sciences Division discuss the first-ever glimpse of nanoscale catalysts in action. More information: http://newscenter.lbl.gov/press-relea...

  6. Dichloromethane photodegradation using titanium catalysts

    SciTech Connect

    Tanguay, J.F.; Suib, S.L.; Coughlin, R.W. )

    1989-06-01

    The use of titanium dioxide and titanium aluminosilicates in the photocatalytic destruction of chlorinated hydrocarbons is investigated. Titanium-exchanged clays, titanium-pillared clays, and titanium dioxide in the amorphous, anatase, and rutile forms are used to photocatalytically degrade dichloromethane to hydrochloric acid and carbon dioxide. Bentonite clays pillared by titanium dioxide are observed to be more catalytically active than titanium-exchanged clays. Clays pillared by titanium aluminum polymeric cations display about the same catalytic activity as that of titanium-exchanged clays. The rutile form of titanium dioxide is the most active catalyst studied for the dichloromethane degradation reaction. The anatase form of titanium dioxide supported on carbon felt was also used as a catalyst. This material is about five times more active than titanium dioxide-pillared clays. Degradation of dichloromethane using any of these catalysts can be enhanced by oxygen enrichment of the reaction solution or by preirradiating the catalyst with light.

  7. Generic Divide and Conquer Internet-Based Computing

    NASA Technical Reports Server (NTRS)

    Follen, Gregory J. (Technical Monitor); Radenski, Atanas

    2003-01-01

    The growth of Internet-based applications and the proliferation of networking technologies have been transforming traditional commercial application areas as well as computer and computational sciences and engineering. This growth stimulates the exploration of Peer to Peer (P2P) software technologies that can open new research and application opportunities not only for the commercial world, but also for the scientific and high-performance computing applications community. The general goal of this project is to achieve better understanding of the transition to Internet-based high-performance computing and to develop solutions for some of the technical challenges of this transition. In particular, we are interested in creating long-term motivation for end users to provide their idle processor time to support computationally intensive tasks. We believe that a practical P2P architecture should provide useful service to both clients with high-performance computing needs and contributors of lower-end computing resources. To achieve this, we are designing dual -service architecture for P2P high-performance divide-and conquer computing; we are also experimenting with a prototype implementation. Our proposed architecture incorporates a master server, utilizes dual satellite servers, and operates on the Internet in a dynamically changing large configuration of lower-end nodes provided by volunteer contributors. A dual satellite server comprises a high-performance computing engine and a lower-end contributor service engine. The computing engine provides generic support for divide and conquer computations. The service engine is intended to provide free useful HTTP-based services to contributors of lower-end computing resources. Our proposed architecture is complementary to and accessible from computational grids, such as Globus, Legion, and Condor. Grids provide remote access to existing higher-end computing resources; in contrast, our goal is to utilize idle processor time of

  8. Revolutions in Global Networking and Collaborations, and the Digital Divide

    NASA Astrophysics Data System (ADS)

    Newman, Harvey

    2007-04-01

    The major physics experiments of the next twenty five years, such as those at the Large Hadron Collider and the International Linear Collider, will break new ground in our understanding of the fundamental interactions, structures and symmetries that govern the nature of matter and spacetime. In order to realize the scientific wealth of these experimental programs, physicists have formed global-scale collaborations and built grid systems where the data is processed, distributed and collaboratively analyzed using networked computing facilities at more than 100 sites around the world. Effective use of these emerging ensembles of facilities and networks presents new challenges in Petabyte-scale data access, processing and distribution, and collaboration across national and international networks on a scale unprecedented in the history of science. The key to meeting these challenges is the effective use of data networks. The bandwidth use by high energy physicists, paralleled by scientists in other fields of data intensive science, continues to grow at several hundred times per decade, and there are indications that this growth is accelerating. This is helping to drive the growth of the major networks serving research and education, as well as mission-oriented networks in the US, Europe, Asia-Pacific, Latin America and across the Atlantic and Pacific oceans. Physicists and computer scientists have together made striking technological advances in recent years, and have developed tools that allow full use of long range 10 gigabit/sec links on a routine basis for the first time. As the science community continues to advance in its development of networks and grid systems, a key concern is the rising Digital Divide between the favored and less-favored regions of the world. Closing the Divide is vital for the health of our global collaborations and our field. In this talk I will review these trends, and focus on the means to reduce the Digital Divide, from the perspective of

  9. Catalyst for carbon monoxide oxidation

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, David R. (Inventor); Davis, Patricia P. (Inventor); Schryer, David R. (Inventor); Brown, Kenneth G. (Inventor); Vannorman, John D. (Inventor)

    1991-01-01

    A catalyst for the combination of CO and O2 to form CO2 which includes a platinum group metal, e.g., platinum; a reducible metal oxide having mulitple valence states, e.g., SnO2; and a compound which can bind water to its structure, e.g., silica gel. This catalyst is ideally suited for application to high powered, pulsed, CO2 lasers operating in a sealed or closed cycle condition.

  10. Catalyst for carbon monoxide oxidation

    NASA Technical Reports Server (NTRS)

    Upchurch, Billy T. (Inventor); Miller, Irvin M. (Inventor); Brown, David R. (Inventor); Davis, Patricia (Inventor); Schryer, David R. (Inventor); Brown, Kenneth G. (Inventor); Vannorman, John D. (Inventor)

    1990-01-01

    A catalyst is disclosed for the combination of CO and O2 to form CO2, which includes a platinum group metal (e.g., platinum); a reducable metal oxide having multiple valence states (e.g., SnO2); and a compound which can bind water to its structure (e.g., silica gel). This catalyst is ideally suited for application to high-powered pulsed, CO2 lasers operating in a sealed or closed-cycle condition.

  11. Divided-pulse nonlinear amplification and simultaneous compression

    SciTech Connect

    Hao, Qiang; Zhang, Qingshan; Sun, Tingting; Chen, Jie; Wang, Yuqing; Guo, Zhengru; Yang, Kangwen; Guo, Zhanhua; Zeng, Heping

    2015-03-09

    We report on a fiber laser system delivering 122 fs pulse duration and 600 mW average power at 1560 nm by the interplay between divided pulse amplification and nonlinear pulse compression. A small-core double-clad erbium-doped fiber with anomalous dispersion carries out the pulse amplification and simultaneously compresses the laser pulses such that a separate compressor is no longer necessary. A numeric simulation reveals the existence of an optimum fiber length for producing transform-limited pulses. Furthermore, frequency doubling to 780 nm with 240 mW average power and 98 fs pulse duration is achieved by using a periodically poled lithium niobate crystal at room temperature.

  12. Size and emotion averaging: costs of dividing attention after all.

    PubMed

    Brand, John; Oriet, Chris; Tottenham, Laurie Sykes

    2012-03-01

    Perceptual averaging is a process by which sets of similar items are represented by summary statistics such as their average size, luminance, or orientation. Researchers have argued that this process is automatic, able to be carried out without interference from concurrent processing. Here, we challenge this conclusion and demonstrate a reliable cost of computing the mean size of circles distinguished by colour (Experiments 1 and 2) and the mean emotionality of faces distinguished by sex (Experiment 3). We also test the viability of two strategies that could have allowed observers to guess the correct response without computing the average size or emotionality of both sets concurrently. We conclude that although two means can be computed concurrently, doing so incurs a cost of dividing attention. PMID:22390476

  13. Flagellation of Pseudomonas aeruginosa in newly divided cells

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Lee, Calvin; Anda, Jaime; Wong, Gerard

    2015-03-01

    For monotrichous bacteria, Pseudomonas aeruginosa, after cell division, one daughter cell inherits the old flagellum from its mother cell, and the other grows a new flagellum during or after cell division. It had been shown that the new flagellum grows at the distal pole of the dividing cell when the two daughter cells haven't completely separated. However, for those daughter cells who grow new flagella after division, it still remains unknown at which pole the new flagellum will grow. Here, by combining our newly developed bacteria family tree tracking techniques with genetic manipulation method, we showed that for the daughter cell who did not inherit the old flagellum, a new flagellum has about 90% chances to grow at the newly formed pole. We proposed a model for flagellation of P. aeruginosa.

  14. The cultural divide: exploring communication barriers between scientists and clinicians

    PubMed Central

    Restifo, Linda L.; Phelan, Gerald R.

    2011-01-01

    Summary Despite remarkable advances in basic biomedical science that have led to improved patient care, there is a wide and persistent gap in the abilities of researchers and clinicians to understand and appreciate each other. In this Editorial, the authors, a scientist and a clinician, discuss the rift between practitioners of laboratory research and clinical medicine. Using their first-hand experience and numerous interviews throughout the United States, they explore the causes of this ‘cultural divide’. Members of both professions use advanced problem-solving skills and typically embark on their career paths with a deeply felt sense of purpose. Nonetheless, differences in classroom education, professional training environments, reward mechanisms and sources of drive contribute to obstacles that inhibit communication, mutual respect and productive collaboration. More than a sociological curiosity, the cultural divide is a significant barrier to the bench-to-bedside goals of translational medicine. Understanding its roots is the first step towards bridging the gap. PMID:21708897

  15. Divided Saddle Theory: A New Idea for Rate Constant Calculation.

    PubMed

    Daru, János; Stirling, András

    2014-03-11

    We present a theory of rare events and derive an algorithm to obtain rates from postprocessing the numerical data of a free energy calculation and the corresponding committor analysis. The formalism is based on the division of the saddle region of the free energy profile of the rare event into two adjacent segments called saddle domains. The method is built on sampling the dynamics within these regions: auxiliary rate constants are defined for the saddle domains and the absolute forward and backward rates are obtained by proper reweighting. We call our approach divided saddle theory (DST). An important advantage of our approach is that it requires only standard computational techniques which are available in most molecular dynamics codes. We demonstrate the potential of DST numerically on two examples: rearrangement of alanine-dipeptide (CH3CO-Ala-NHCH3) conformers and the intramolecular Cope reaction of the fluxional barbaralane molecule.

  16. Four Sided Domains in Hierarchical Space Dividing Patterns

    NASA Astrophysics Data System (ADS)

    Bohn, S.; Douady, S.; Couder, Y.

    2005-02-01

    The cracks observed in the glaze of ceramics form networks, which divide the 2D plane into domains. It is shown that, on the average, the number of sides of these domains is four. This contrasts with the usual 2D space divisions observed in Voronoi tessellation or 2D soap froths. In the latter networks, the number of sides of a domain coincides with the number of its neighbors, which, according to Euler’s theorem, has to be six on average. The four sided property observed in cracks is the result of a formation process which can be understood as the successive divisions of domains with no later reorganization. It is generic for all networks having such hierarchical construction rules. We introduce a “geometrical charge,” analogous to Euler’s topological charge, as the difference from four of the number of sides of a domain. It is preserved during the pattern formation of the crack pattern.

  17. Characterization of Na+- beta-Zeolite Supported Pd and Pd Ag Bimetallic Catalysts using EXAFS, TEM and Flow Reactor

    SciTech Connect

    Huang,W.; Lobo, R.; Chen, J.

    2008-01-01

    Flow reactor studies of the selective hydrogenation of acetylene in the presence of ethylene have been performed on Na+ exchanged {beta}-zeolite supported Pd, Ag and PdAg catalysts, as an extension of our previous batch reactor studies [W. Huang, J.R. McCormick, R.F. Lobo, J.G. Chen, J. Catal. 246 (2007) 40-51]. Results from flow reactor studies show that the PdAg/Na+-{beta}-zeolite bimetallic catalyst has lower activity than Pd/Na+-{beta}-zeolite monometallic catalyst, while Ag/Na+-{beta}-zeolite does not show any activity for acetylene hydrogenation. However, the selectivity for the PdAg bimetallic catalyst is much higher than that for either the Pd catalyst or Ag catalyst. The selectivity to byproduct (ethane) is greatly inhibited on the PdAg bimetallic catalyst as well. The results from the current flow reactor studies confirmed the pervious results from batch reactor studies [W. Huang, J.R. McCormick, R.F. Lobo, J.G. Chen, J. Catal. 246 (2007) 40-51]. In addition, we used transmission electron microscope (TEM), extended X-ray absorption fine structure (EXAFS), and FTIR of CO adsorption to confirm the formation of Pd-Ag bimetallic alloy in the PdAg/Na+-{beta}-zeolite catalyst.

  18. Divided Attention and Processes Underlying Sense of Agency

    PubMed Central

    Wen, Wen; Yamashita, Atsushi; Asama, Hajime

    2016-01-01

    Sense of agency refers to the subjective feeling of controlling events through one’s behavior or will. Sense of agency results from matching predictions of one’s own actions with actual feedback regarding the action. Furthermore, when an action involves a cued goal, performance-based inference contributes to sense of agency. That is, if people achieve their goal, they would believe themselves to be in control. Previous studies have shown that both action-effect comparison and performance-based inference contribute to sense of agency; however, the dominance of one process over the other may shift based on task conditions such as the presence or absence of specific goals. In this study, we examined the influence of divided attention on these two processes underlying sense of agency in two conditions. In the experimental task, participants continuously controlled a moving dot for 10 s while maintaining a string of three or seven digits in working memory. We found that when there was no cued goal (no-cued-goal condition), sense of agency was impaired by high cognitive load. Contrastingly, when participants controlled the dot based on a cued goal (cued-goal-directed condition), their sense of agency was lower than in the no-cued-goal condition and was not affected by cognitive load. The results suggest that the action-effect comparison process underlying sense of agency requires attention. On the other hand, the weaker influence of divided attention in the cued-goal-directed condition could be attributed to the dominance of performance-based inference, which is probably automatic. PMID:26858680

  19. Further reflections on the humanistic psychology-positive psychology divide.

    PubMed

    Waterman, Alan S

    2014-01-01

    Replies to comments by Morley (see record 2014-01475-010), Serlin (see record 2014-01475-011), Friedman (see record 2014-01475-012), Churchill and Mruk (see record 2014-01475-013), and Schneider (see record 2014-01475-014) on the current author's original article "The humanistic psychology-positive psychology divide: Contrasts in philosophical foundations" (see record 2013-12501-001). The article contrasting humanistic psychology and positive psychology with respect to their ontological, epistemological, and practical philosophical foundations has generated commentaries from leading proponents of varying perspectives within humanistic psychology. There is a great deal of material within those commentaries with which the current author is in full accord. It is worth noting at the outset that no one appears to be challenging the observations (a) that published exchanges between proponents of humanistic and positive psychology have been marked by tension and ambivalence, albeit with occasional efforts at reconciliation and rapprochement; (b) that proponents of the two perspectives differ with respect to the philosophers they most frequently cite in their writings; or (c) that such citations reflect the philosophical assumptions serving as foundations for the theoretical, research, and counseling/therapeutic endeavors of psychologists in both groups. The principal points of concurrence in the critiques published here are that the current underestimates the extent to which mutually supportive, collaborative work can be accomplished across the philosophical divide and that the recommendations the current author has made has advanced serious potential negative consequences for the field. The current author will address these points here in the reply, although space does not permit him to address other substantive points raised by individual commentators.

  20. Older people and digital disengagement: a fourth digital divide?

    PubMed

    Olphert, Wendy; Damodaran, Leela

    2013-01-01

    Digital technologies are becoming more pervasive in all areas of society. Enabling everyone to have access and capability to use the Internet and associated digital technologies, summed up in the term 'digital inclusion', is seen to have wide-ranging benefits to the individual, to the economy and to society. For older people, being digitally included can help them to maintain their independence, social connectedness and sense of worth in the face of declining health or limited capabilities, as well as also offering new opportunities to improve their quality of life. At present however, access to the technology and to the benefits is not equally distributed either between or within nations, and older people tend to be on the 'wrong' side of what is termed the 'digital divide'. Governments globally are developing strategies to promote digital inclusion and indeed Internet uptake is increasing steadily, including amongst older people. However, such strategies have focussed on getting people online, and there appears to be an assumption that once someone is online they will remain 'digitally engaged'. In fact statistics show that some users give up using the Internet, and there is emerging evidence that older people are more vulnerable to the factors which can lead to this outcome. The authors see this phenomenon as a potential but largely unrecognised 'fourth digital divide' which has serious implications for social inclusion. The objectives of this article are (a) to raise awareness of the phenomenon of digital disengagement by considering some of the emerging evidence, (b) to explore some of the potential implications of not recognising and therefore not addressing the needs of the digitally disengaged older population, and (c) to reveal the prevailing gap in knowledge which future research should address.

  1. Deeper Probing of the Fine-structure Constant

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal

    2008-10-01

    In our earlier attempt in [1] to derive fine-structure constant, one subtle reason why the natural logarithm of the age of the universe in Planck times comes out to be slightly greater than the reciprocal of the fine structure constant is that the variable W in Boltzmann's expression should be the age of the universe in Planck times divided by the bit depth for our specific application. Since we cannot decode the nature's bit depth, we cannot come up with the expected value of ALPHA. For an assumed bit depth of 10, the reciprocal of ALPHA goes down by ln10 (2.3) without having a significant impact on the order of magnitude of the baud rate (baud rate = bits per second/bit depth = 10^43 (Planck time/second)/10 = 10^42). Use of terms and equations from informatics in both of author's interrelated abstracts this meeting is meant to engage a wider audience simply. [1] Goradia, Shantilal ``What is Fine-structure Constant?'' http://www.arXiv.org/pdf/physics/0210040v3.

  2. New approaches in catalyst manufacture

    SciTech Connect

    Lostaglio, V.J.; Carruthers, J.D.

    1986-03-01

    Changes in both petroleum refinery feedstocks and refinery product slates during the past 10 years have necessitated new approaches in catalyst manufacture. New hydrotreating catalysts are expected to improve polynuclear aromatic saturation, and to increase cetane index, mild hydrocracking, asphaltene conversion, and contaminant metal removal. Sulfur and nitrogen removal were once considered the sole benefits of hydroprocessing. To accommodate these needs, catalyst manufacturers have focused added attention on defining and achieving rigorous physical and chemical specifications for each new catalyst. It is considered essential to continually improve quality and process control in each manufacturing step. In addition, manufacturers have introduced new technology both in the process and in the evaluation of product. The importance of pore size distribution (PSD), for example, has been appreciated for 20 years or more but it is only within the past 10 years that routine measurement of PSD by mercury and/or nitrogen porosimetry has been applied throughout the entire manufacturing process. A greater emphasis on heavy oil hydrotreating has spurred demands for wide pore catalysts of small external dimensions to overcome the problems of diffusion-limited reactions. In turn, however, these properties may create problems with crush strength and catalyst attrition.

  3. Waste catalysts for waste polymer.

    PubMed

    Salmiaton, A; Garforth, A

    2007-01-01

    Catalytic cracking of high-density polyethylene (HDPE) over fluid catalytic cracking (FCC) catalysts (1:6 ratio) was carried out using a laboratory fluidized bed reactor operating at 450 degrees C. Two fresh and two steam deactivated commercial FCC catalysts with different levels of rare earth oxide (REO) were compared as well as two used FCC catalysts (E-Cats) with different levels of metal poisoning. Also, inert microspheres (MS3) were used as a fluidizing agent to compare with thermal cracking process at BP pilot plant at Grangemouth, Scotland, which used sand as its fluidizing agent. The results of HDPE degradation in terms of yield of volatile hydrocarbon product are fresh FCC catalysts>steamed FCC catalysts approximately used FCC catalysts. The thermal cracking process using MS3 showed that at 450 degrees C, the product distribution gave 46 wt% wax, 14% hydrocarbon gases, 8% gasoline, 0.1% coke and 32% nonvolatile product. In general, the product yields from HDPE cracking showed that the level of metal contamination (nickel and vanadium) did not affect the product stream generated from polymer cracking. This study gives promising results as an alternative technique for the cracking and recycling of polymer waste. PMID:17084608

  4. Nano-Engineered Catalysts for Direct Methanol Fuel Cells

    NASA Technical Reports Server (NTRS)

    Myung, Nosang; Narayanan, Sekharipuram; Wiberg, Dean

    2008-01-01

    Nano-engineered catalysts, and a method of fabricating them, have been developed in a continuing effort to improve the performances of direct methanol fuel cells as candidate power sources to supplant primary and secondary batteries in a variety of portable electronic products. In order to realize the potential for high energy densities (as much as 1.5 W h/g) of direct methanol fuel cells, it will be necessary to optimize the chemical compositions and geometric configurations of catalyst layers and electrode structures. High performance can be achieved when catalyst particles and electrode structures have the necessary small feature sizes (typically of the order of nanometers), large surface areas, optimal metal compositions, high porosity, and hydrophobicity. The present method involves electrodeposition of one or more catalytic metal(s) or a catalytic-metal/polytetrafluoroethylene nanocomposite on an alumina nanotemplate. The alumina nanotemplate is then dissolved, leaving the desired metal or metal/polytetrafluoroethylene-composite catalyst layer. Unlike some prior methods of making fine metal catalysts, this method does not involve processing at elevated temperature; all processing can be done at room temperature. In addition, this method involves fewer steps and is more amenable to scaling up for mass production. Alumina nanotemplates are porous alumina membranes that have been fabricated, variously, by anodizing either pure aluminum or aluminum that has been deposited on silicon by electronbeam evaporation. The diameters of the pores (7 to 300 nm), areal densities of pores (as much as 7 x 10(exp 10)sq cm), and lengths of pores (up to about 100 nm) can be tailored by selection of fabrication conditions. In a given case, the catalytic metal, catalytic metal alloy, or catalytic metal/ polytetrafluoroethylene composite is electrodeposited in the pores of the alumina nanotemplate. The dimensions of the pores, together with the electrodeposition conditions

  5. Production of biodiesel fuel from canola oil with dimethyl carbonate using an active sodium methoxide catalyst prepared by crystallization.

    PubMed

    Kai, Takami; Mak, Goon Lum; Wada, Shohei; Nakazato, Tsutomu; Takanashi, Hirokazu; Uemura, Yoshimitsu

    2014-07-01

    In this study, a novel method for the production of biodiesel under mild conditions using fine particles of sodium methoxide formed in dimethyl carbonate (DMC) is proposed. Biodiesel is generally produced from vegetable oils by the transesterification of triglycerides with methanol. However, this reaction produces glycerol as a byproduct, and raw materials are not effectively utilized. Transesterification with DMC has recently been studied because glycerol is not formed in the process. Although solid-state sodium methoxide has been reported to be inactive for this reaction, the catalytic activity dramatically increased with the preparation of fine catalyst powders by crystallization. The transesterification of canola oil with DMC was studied using this catalyst for the preparation of biodiesel. A conversion greater than 96% was obtained at 65°C for 2h with a 3:1M ratio of DMC and oil and 2.0 wt% catalyst. PMID:24813567

  6. Production of biodiesel fuel from canola oil with dimethyl carbonate using an active sodium methoxide catalyst prepared by crystallization.

    PubMed

    Kai, Takami; Mak, Goon Lum; Wada, Shohei; Nakazato, Tsutomu; Takanashi, Hirokazu; Uemura, Yoshimitsu

    2014-07-01

    In this study, a novel method for the production of biodiesel under mild conditions using fine particles of sodium methoxide formed in dimethyl carbonate (DMC) is proposed. Biodiesel is generally produced from vegetable oils by the transesterification of triglycerides with methanol. However, this reaction produces glycerol as a byproduct, and raw materials are not effectively utilized. Transesterification with DMC has recently been studied because glycerol is not formed in the process. Although solid-state sodium methoxide has been reported to be inactive for this reaction, the catalytic activity dramatically increased with the preparation of fine catalyst powders by crystallization. The transesterification of canola oil with DMC was studied using this catalyst for the preparation of biodiesel. A conversion greater than 96% was obtained at 65°C for 2h with a 3:1M ratio of DMC and oil and 2.0 wt% catalyst.

  7. Relative importance of temporal envelope and fine structure in lexical-tone perception (L)

    NASA Astrophysics Data System (ADS)

    Xu, Li; Pfingst, Bryan E.

    2003-12-01

    The relative importance of temporal envelope and fine structure in speech and music perception was investigated by Smith et al. [Nature (London) 416, 87-90 (2002)] using ``auditory chimera'' in which the envelope from one sound was paired with the fine structure of another. Smith et al. found that, when 4 to 16 frequency bands were used, recognition of English speech was dominated by the envelope, whereas recognition of melody was dominated by the fine structure. In the present study, Mandarin Chinese monosyllables were divided into 4, 8, or 16 frequency bands and the fine structure and envelope of one tone pattern were exchanged with those of another tone pattern of the same monosyllable. Five normal-hearing native Mandarin Chinese speakers completed a four-alternative forced-choice tone-identification task. In the vast majority of trials, subjects based their identification of the monosyllables on the fine structure rather than the envelope. Thus, the relative importance of envelope and fine structure for lexical-tone perception resembled that for melody recognition rather than that for English speech recognition. Delivering fine-structure information in cochlear implant stimulation could be particularly beneficial for lexical-tone perception.

  8. Northwest outlet channels of Lake Agassiz, isostatic tilting and a migrating continental drainage divide, Saskatchewan, Canada

    NASA Astrophysics Data System (ADS)

    Fisher, Timothy G.; Souch, Catherine

    1998-10-01

    Lake cores obtained from the northwest outlet of glacial Lake Agassiz in northwest Saskatchewan, Canada, provide a minimum date for the cessation of the flood from the northwest outlet, and a chronology for abandonment of mid-Holocene channels that presently straddle the Mackenzie and Churchill drainage divide. The stratigraphy of a vibracore taken from Long Lake consists of a lower pebble gravel fining to massive sand, silty-clay and then fibrous peat. Wood fragments from the base of the clay yielded an accelerator mass spectrometry (AMS) date of 9120 BP. Because the lake is scour in origin and is in the head of the spillway, the date is considered to be a minimum estimate for cessation of the flood from the northwest outlet at the beginning of the Emerson Phase. A vibracore taken at Haas Lake in an abandoned channel surrounded by muskeg with no influent streams, consists of 0.8 m of stratified, pebble gravel containing abundant shell and wood fragments, overlain by 1.62 m of gyttja with a sharp, conformable lower contact. AMS dates range from 5590 BP from the topmost gravel to 3080 BP within the gyttja. The gravel is interpreted as fluvial, recording a river draining Wasekamio Lake north into the Clearwater River across the present-day drainage divide. Today, a drop of 2 m occurs from Wasekamio Lake southeast to Lac Ile-a-la-Crosse, along 150 km of lake basins parallel to the Cree Lake Moraine. The dates from Haas Lake suggest that before 5200 BP, the drainage divide was about 100 km further southeast, implying that during the Emerson Phase, lake level was controlled by a sill near Flatstone Lake at about 430 m instead of between Wasekamio Lake and the Clearwater River, as was previously proposed. Holocene differential isostatic uplift caused the flow reversal in the upper Churchill basin. Anastomosed channels at the mouth of rivers flowing north into lakes indicate that uplift is still active in the area today.

  9. The innovation catalysts.

    PubMed

    Martin, Roger L

    2011-06-01

    A few years ago the software development company Intuit realized that it needed a new approach to galvanizing customers. The company's Net Promoter Score was faltering, and customer recommendations of new products were especially disappointing. Intuit decided to hold a two-day, off-site meeting for the company's top 300 managers with a focus on the role of design in innovation. One of the days was dedicated to a program called Design for Delight. The centerpiece of the day was a PowerPoint presentation by Intuit founder Scott Cook, who realized midway through that he was no Steve Jobs: The managers listened dutifully, but there was little energy in the room. By contrast, a subsequent exercise in which the participants worked through a design challenge by creating prototypes, getting feedback, iterating, and refining, had them mesmerized. The eventual result was the creation of a team of nine design-thinking coaches--"innovation catalysts"--from across Intuit who were made available to help any work group create prototypes, run experiments, and learn from customers. The process includes a "painstorm" (to determine the customer's greatest pain point), a "soljam" (to generate and then winnow possible solutions), and a "code-jam" (to write code "good enough" to take to customers within two weeks). Design for Delight has enabled employees throughout Intuit to move from satisfying customers to delighting them.

  10. The innovation catalysts.

    PubMed

    Martin, Roger L

    2011-06-01

    A few years ago the software development company Intuit realized that it needed a new approach to galvanizing customers. The company's Net Promoter Score was faltering, and customer recommendations of new products were especially disappointing. Intuit decided to hold a two-day, off-site meeting for the company's top 300 managers with a focus on the role of design in innovation. One of the days was dedicated to a program called Design for Delight. The centerpiece of the day was a PowerPoint presentation by Intuit founder Scott Cook, who realized midway through that he was no Steve Jobs: The managers listened dutifully, but there was little energy in the room. By contrast, a subsequent exercise in which the participants worked through a design challenge by creating prototypes, getting feedback, iterating, and refining, had them mesmerized. The eventual result was the creation of a team of nine design-thinking coaches--"innovation catalysts"--from across Intuit who were made available to help any work group create prototypes, run experiments, and learn from customers. The process includes a "painstorm" (to determine the customer's greatest pain point), a "soljam" (to generate and then winnow possible solutions), and a "code-jam" (to write code "good enough" to take to customers within two weeks). Design for Delight has enabled employees throughout Intuit to move from satisfying customers to delighting them. PMID:21714388

  11. Increased sulfur tolerance of Pt/KL catalysts prepared by vapor-phase impregnation and containing a Tm promoter

    SciTech Connect

    Jacobs, G.; Ghadiali, F.; Pisanu, A.; Padro, C.L.; Borgna, A.; Alvarez, W.E.; Resasco, D.E.

    2000-04-01

    Tm-containing Pt/KL catalysts were prepared by a variety of techniques, including incipient wetness impregnation (IWI), ion exchange (IE), and vapor-phase impregnation (VPI) methods. The Pt morphology resulting from the addition of Tm and Pt sequentially, using the VPI method, was found to yield the greatest enhancement to the aromatization performance of the Pt/KL catalysts studied. The presence of Tm in the sequential VPI Pt/Tm/KL catalyst resulted reproducibly in a catalyst with higher Pt dispersion than that in an unpromoted VPI catalyst, as determined by EXAFS analysis and DRIFTS of adsorbed CO. VPI catalysts give more finely dispersed Pt clusters than either conventional IWI or IE methods. From TPO of poisoned catalysts, Tm was also found to act as a getter for sulfur, so it delays the poisoning of Pt under sulfur-containing feeds, as further evidenced by reaction studies. In addition, the initial activity of the Tm-promoted VPI catalysts was found to be higher than that of the unpromoted Pt/KL VPI catalysts, suggesting that Tm may directly modify Pt or even participate in accelerating the aromatization reaction. The amount and method of incorporation of Tm were found to be critical to the morphology of the Pt clusters and, subsequently, to catalyst performance under sulfur-free and sulfur-poisoned reaction conditions. While the sequential vapor-phase impregnation method with a small amount of Tm (0.15%) yielded a catalyst with improved catalytic properties, some of the other methods such as coimpregnation of Pt and Tm were found to hinder the dispersion of Pt. This may cause the blocking of the L-zeolite channels, as demonstrated by DRIFTS of adsorbed CO, and a higher deactivation rate in the reaction

  12. Characterization and functionalities of Pd/hydrotalcite catalysts

    NASA Astrophysics Data System (ADS)

    Naresh, Dhachapally; Kumar, Vanama Pavan; Harisekhar, Mitta; Nagaraju, Nekkala; Putrakumar, Balla; Chary, Komandur V. R.

    2014-09-01

    A series of palladium supported on calcined hydrotalcite (CHT) catalysts with varying palladium (Pd) loadings (1.0-8.0 wt%) were prepared by impregnation method. Their catalytic performance was evaluated for the reductive amination of phenol to aniline that showed a tremendous interest in the chemical industry. The catalysts were characterized by BET surface area, XRD, TEM, XPS, TPR of H2, TPD of CO2 and CO chemisorption. BET surface area decreased continuously with increase in Pd content. XRD results confirmed the changes in the crystalline phases with altering Pd content. TEM results showed the formation of fine particles at lower loadings and agglomerates at higher loadings. TPR profiles revealed that the reducibility increases with increase of Pd loading. CO2 TPD results illustrate the catalysts basicity increases with increase of Pd loading up to 4.0 wt% and decreases at higher loadings. Pd dispersion, metal area and crystallite sizes were determined by CO chemisorption method. Pd dispersion and metal area decreases with increase of Pd content and crystallite sizes. The results demonstrated that the Pd dispersion and basic properties are depending on the Pd loading. The catalytic performance clearly showed that the increase Pd loading the conversion of phenol increased up to 2.0 wt% and level off beyond the loading. The catalytic properties are well correlated with the active Pd sites determined by CO chemisorption, dispersion and basicity.

  13. Catalyst suppliers further consolidate business units

    SciTech Connect

    Rhodes, A.K.

    1993-10-11

    The petroleum-refining catalyst industry sustained significant reorganization in 1993. A joint venture between two previous competitors and the consolidated of two sister companies reflect general trends in the global market-place. The Journal's latest survey lists more than 820 unique catalysts. This reduction of some 220 catalysts since the last complete catalyst compilation is partially the result of the deletion of some of the more specialized catalysts from this year's survey. Other factors contributing to this decrease include industry rationalization and the listing of catalyst families instead of individual products--especially in the fluid catalytic cracking category. The Journal's international refining-catalyst compilation lists catalysts manufactured for all major catalytic refinery processes by essentially all the world's petroleum catalyst producers and suppliers. The objective of the survey is two-fold: first, to list each catalyst by its specific designation or supplier identification in its process application category (for instance, hydrocracking); and second, to differentiate each catalyst from the others in that category. These differentiations can be made in terms of either the catalyst's application (for example, feedstock characteristics) or its physical characteristics (for instance, particle size or activity). The compilation is designed to provide a ready reference for both refiners and catalyst manufacturers. In the process, it may also help sort out the sometimes confusing nomenclature used to describe these catalysts.

  14. Catalyst for coal liquefaction process

    DOEpatents

    Huibers, Derk T. A.; Kang, Chia-Chen C.

    1984-01-01

    An improved catalyst for a coal liquefaction process; e.g., the H-Coal Process, for converting coal into liquid fuels, and where the conversion is carried out in an ebullated-catalyst-bed reactor wherein the coal contacts catalyst particles and is converted, in addition to liquid fuels, to gas and residual oil which includes preasphaltenes and asphaltenes. The improvement comprises a catalyst selected from the group consisting of the oxides of nickel molybdenum, cobalt molybdenum, cobalt tungsten, and nickel tungsten on a carrier of alumina, silica, or a combination of alumina and silica. The catalyst has a total pore volume of about 0.500 to about 0.900 cc/g and the pore volume comprises micropores, intermediate pores and macropores, the surface of the intermediate pores being sufficiently large to convert the preasphaltenes to asphaltenes and lighter molecules. The conversion of the asphaltenes takes place on the surface of micropores. The macropores are for metal deposition and to prevent catalyst agglomeration. The micropores have diameters between about 50 and about 200 angstroms (.ANG.) and comprise from about 50 to about 80% of the pore volume, whereas the intermediate pores have diameters between about 200 and 2000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume, and the macropores have diameters between about 2000 and about 10,000 angstroms (.ANG.) and comprise from about 10 to about 25% of the pore volume. The catalysts are further improved where they contain promoters. Such promoters include the oxides of vanadium, tungsten, copper, iron and barium, tin chloride, tin fluoride and rare earth metals.

  15. Pretreatment of CO oxidation catalysts

    NASA Technical Reports Server (NTRS)

    Vannorman, John D.

    1988-01-01

    CO oxidation catalysts with high activity in the range of 25 C to 100 C are important for long-life, closed-cycle operation of pulsed carbon dioxide 2 lasers. A reductive pretreatment with either CO or H sub 2 was shown to significantly enhance the activity of a commerically-available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above caused an initial dip in observed CO or O sub 2 loss or CO sub 2 formation in a test gas mixture of 1 percent CO and 0.5 percent O sub 2 in a He gas matrix before a steady-state yield was obtained. This dip was found to be caused by dehydration of the surface of the catalyst and was readily eliminated by humidifying the catalyst or the test gas mixture. It was also found that too much moisture resulted in a lower overall yield of CO sub 2. Under similar conditions, it is hypothesized that the effect of the humidification is to increase the concentration of OH groups on the surface of the catalyst. The effect of having high concentration of CO sub 2 in the test gas mixture upon the loss of CO and O sub 2 as well as the effect of periods of relaxation of the catalyst under non-test gas conditions was studied. The purpose of these studies was to gain an insight into the mechanism of CO oxidation on this type of catalyst.

  16. Fine structures at pore boundary

    NASA Astrophysics Data System (ADS)

    Bharti, L.; Quintero Noda, C.; Joshi, C.; Rakesh, S.; Pandya, A.

    2016-10-01

    We present high resolution observations of fine structures at pore boundaries. The inner part of granules towards umbra show dark striations which evolve into a filamentary structure with dark core and `Y' shape at the head of the filaments. These filaments migrate into the umbra similar to penumbral filaments. These filaments show higher temperature, lower magnetic field strength and more inclined field compared to the background umbra. The optical depth stratification of physical quantities suggests their similarity with penumbral filaments. However, line-of-sight velocity pattern is different from penumbral filaments where they show downflows in the deeper layers of the atmosphere while the higher layers show upflows. These observations show filamentation in a simple magnetic configuration.

  17. Fine structure of cluster decays

    SciTech Connect

    Dumitrescu, O.

    1994-03-01

    Within the one level {ital R}-matrix approach, expressions are derived for the hindrance factors of cluster radioactive decays in which {ital y} {ital the} {ital shell} {ital model} {ital with} {ital effective} {ital residual} {ital interactions} [{ital e}.{ital g}.,{ital thelar} in the Michigan State University version for nearly spherical nuclei, or the enlarged superfluid model (ESM) recently proposed for deformed nuclei]. The exterior wave functions are calculated from a cluster-nucleus double-folding model potential obtained with the M3Y interaction. As examples of the cluster decay fine structure we analyzed the particular cases of {alpha} decay of {sup 241}Am and {sup 243}Cm, {sup 14}C decay of {sup 223}Ra, and {sup 34}Si decay of {sup 243}Cm. Good agreement with the experimental data is obtained.

  18. Fine Structure in Solar Flares.

    PubMed

    Warren

    2000-06-20

    We present observations of several large two-ribbon flares observed with both the Transition Region and Coronal Explorer (TRACE) and the soft X-ray telescope on Yohkoh. The high spatial resolution TRACE observations show that solar flare plasma is generally not confined to a single loop or even a few isolated loops but to a multitude of fine coronal structures. These observations also suggest that the high-temperature flare plasma generally appears diffuse while the cooler ( less, similar2 MK) postflare plasma is looplike. We conjecture that the diffuse appearance of the high-temperature flare emission seen with TRACE is due to a combination of the emission measure structure of these flares and the instrumental temperature response and does not reflect fundamental differences in plasma morphology at the different temperatures.

  19. Tracking Petroleum Refinery Emission Events Using Lanthanum and Lanthanides as Elemental Markers for Fine Particulate Matter

    NASA Astrophysics Data System (ADS)

    Kulkarni, P.; Chellam, S.; Fraser, M. P.

    2007-12-01

    This presentation reports the development and application of an analytical method to quantify the rare earth elements (REEs) in atmospheric particulate matter and emissions of catalyst material from the petroleum refining industry. Inductively coupled plasma - mass spectrometry following high temperature/high pressure microwave digestion has been used to study the REE composition of several fresh and spent catalysts used in fluidized-bed catalytic cracking (FCC) units in petroleum refineries as well as in ambient atmospheric fine particulate matter collected in Houston, TX. The results show that the routine emissions from local FCC units in Houston contribute a constant and low amount to ambient PM2.5 of ~0.1 micrograms per cubic meter. However, a significant (33 - 106 fold) increase in the contributions of FCC emissions to PM2.5 is quantified during an upset emission event compared with background levels associated with routine operation. The impact of emissions from the local refinery that reported the emission event was tracked to a site approximately 50 km downwind from the source, illustrating the potential exposure of humans over a large geographical area through the long-range transport of atmospheric fine particles as well as the power of elemental signatures to understand the sources of fine particles.

  20. Effects of Divided Attention at Retrieval on Conceptual Implicit Memory

    PubMed Central

    Prull, Matthew W.; Lawless, Courtney; Marshall, Helen M.; Sherman, Annabella T. K.

    2016-01-01

    This study investigated whether conceptual implicit memory is sensitive to process-specific interference at the time of retrieval. Participants performed the implicit memory test of category exemplar generation (CEG; Experiments 1 and 3), or the matched explicit memory test of category-cued recall (Experiment 2), both of which are conceptually driven memory tasks, under one of two divided attention (DA) conditions in which participants simultaneously performed a distracting task. The distracting task was either syllable judgments (dissimilar processes), or semantic judgments (similar processes) on unrelated words. Compared to full attention (FA) in which no distracting task was performed, DA had no effect on CEG priming overall, but reduced category-cued recall similarly regardless of distractor task. Analyses of distractor task performance also revealed differences between implicit and explicit memory retrieval. The evidence suggests that, whereas explicit memory retrieval requires attentional resources and is disrupted by semantic and phonological distracting tasks, conceptual implicit memory is automatic and unaffected even when distractor and memory tasks involve similar processes. PMID:26834678

  1. Disability Divides in India: Evidence from the 2011 Census

    PubMed Central

    Saikia, Nandita; Bora, Jayanta Kumar; Jasilionis, Domantas; Shkolnikov, Vladimir M.

    2016-01-01

    Background Understanding the socioeconomic and regional divides in disability prevalence in India has considerable relevance for designing public health policies and programs. Objectives The aim of the present study is to quantify the prevalence of disability by gender, region (rural and urban; states and districts), and caste. We also examine the association between disability prevalence and the major socio-demographic and socioeconomic characteristics of the districts in India. Methods Age-standardized disability prevalence (ASDP) was calculated using 2011 census data and applying the WHO World Standard Population. A regression analysis was carried out to examine the association between disability prevalence and demographic and socioeconomic characteristics across districts of India. Results The study found that ASDP varies substantially across districts and is higher among women, rural dwellers, and members of scheduled tribes (STs) and scheduled castes (SCs). The regression model showed that the disability rate in districts rises with increasing proportions of the population who are urban dwellers, aged 65 or older, members of STs, and living in dilapidated housing; and that the disability prevalence decreases with increasing proportions of the female population who are literate, and of the general population who are working and have access to safe drinking water. Conclusion As the burden of disability falls disproportionately across geographic regions and socioeconomic groups, public health policies in India should take this variation into account. The definition of disability used in the census should be modified to generate internationally comparable estimates of disability prevalence. PMID:27490469

  2. Movement Synchrony Forges Social Bonds across Group Divides

    PubMed Central

    Tunçgenç, Bahar; Cohen, Emma

    2016-01-01

    Group dynamics play an important role in the social interactions of both children and adults. A large amount of research has shown that merely being allocated to arbitrarily defined groups can evoke disproportionately positive attitudes toward one's in-group and negative attitudes toward out-groups, and that these biases emerge in early childhood. This prompts important empirical questions with far-reaching theoretical and applied significance. How robust are these inter-group biases? Can biases be mitigated by behaviors known to bond individuals and groups together? How can bonds be forged across existing group divides? To explore these questions, we examined the bonding effects of interpersonal synchrony on minimally constructed groups in a controlled experiment. In-group and out-group bonding were assessed using questionnaires administered before and after a task in which groups performed movements either synchronously or non-synchronously in a between-participants design. We also developed an implicit behavioral measure, the Island Game, in which physical proximity was used as an indirect measure of interpersonal closeness. Self-report and behavioral measures showed increased bonding between groups after synchronous movement. Bonding with the out-group was significantly higher in the condition in which movements were performed synchronously than when movements were performed non-synchronously between groups. The findings are discussed in terms of their importance for the developmental social psychology of group dynamics as well as their implications for applied intervention programs. PMID:27303341

  3. Flood variability east of Australia’s Great Dividing Range

    NASA Astrophysics Data System (ADS)

    Rustomji, Paul; Bennett, Neil; Chiew, Francis

    2009-08-01

    SummaryThe variability of flow in river channels influences the spatial and temporal variability of many biophysical processes including the transport of sediment and waterborne pollutants and the recruitment of aquatic animals and plants. In this study, inter- and intra-basin patterns of flood variability are examined for catchments east of Australia's Great Dividing Range. Three measures of flood variability are explored with uncertainty quantified using bootstrap resampling. The two preferred measures of flood variability (namely a flood quantile ratio and a power law scaling coefficient) produced similar results. Catchments in the wet tropics of far north Queensland experience low flood variability. Flood variability increased southwards through Queensland, reaching a maximum in the vicinity of the Fitzroy and Burnett River basins. The small near-coast catchments of southern Queensland and northern New Wales experience low flood variability. Flood variability is also high in the southern Hunter River and Hawkesbury-Nepean basins. Using L-moment ratio diagrams with data from 424 streamflow stations, we also conclude that the Generalised Pareto distribution is preferable for modelling flood frequency curves for this region. These results provide a regional perspective that can be used to develop new hypotheses about the effects of hydrologic variability on the biophysical characteristics of these Australian rivers.

  4. Divided attention limits perception of 3-D object shapes.

    PubMed

    Scharff, Alec; Palmer, John; Moore, Cathleen M

    2013-01-01

    Can one perceive multiple object shapes at once? We tested two benchmark models of object shape perception under divided attention: an unlimited-capacity and a fixed-capacity model. Under unlimited-capacity models, shapes are analyzed independently and in parallel. Under fixed-capacity models, shapes are processed at a fixed rate (as in a serial model). To distinguish these models, we compared conditions in which observers were presented with simultaneous or sequential presentations of a fixed number of objects (The extended simultaneous-sequential method: Scharff, Palmer, & Moore, 2011a, 2011b). We used novel physical objects as stimuli, minimizing the role of semantic categorization in the task. Observers searched for a specific object among similar objects. We ensured that non-shape stimulus properties such as color and texture could not be used to complete the task. Unpredictable viewing angles were used to preclude image-matching strategies. The results rejected unlimited-capacity models for object shape perception and were consistent with the predictions of a fixed-capacity model. In contrast, a task that required observers to recognize 2-D shapes with predictable viewing angles yielded an unlimited capacity result. Further experiments ruled out alternative explanations for the capacity limit, leading us to conclude that there is a fixed-capacity limit on the ability to perceive 3-D object shapes.

  5. Two-Volt Josephson Arbitrary Waveform Synthesizer Using Wilkinson Dividers

    PubMed Central

    Flowers-Jacobs, Nathan E.; Fox, Anna E.; Dresselhaus, Paul D.; Schwall, Robert E.; Benz, Samuel P.

    2016-01-01

    The root-mean-square (rms) output voltage of the NIST Josephson arbitrary waveform synthesizer (JAWS) has been doubled from 1 V to a record 2 V by combining two new 1 V chips on a cryocooler. This higher voltage will improve calibrations of ac thermal voltage converters and precision voltage measurements that require state-of-the-art quantum accuracy, stability, and signal-to-noise ratio. We achieved this increase in output voltage by using four on-chip Wilkinson dividers and eight inner-outer dc blocks, which enable biasing of eight Josephson junction (JJ) arrays with high-speed inputs from only four high-speed pulse generator channels. This approach halves the number of pulse generator channels required in future JAWS systems. We also implemented on-chip superconducting interconnects between JJ arrays, which reduces systematic errors and enables a new modular chip package. Finally, we demonstrate a new technique for measuring and visualizing the operating current range that reduces the measurement time by almost two orders of magnitude and reveals the relationship between distortion in the output spectrum and output pulse sequence errors. PMID:27453676

  6. Application System Architecture for Cellular Phones by Dividing Interaction Logics

    NASA Astrophysics Data System (ADS)

    Kitamura, Misayo; Todoroki, Nobutoshi; Akiyoshi, Masanori; Kojima, Taizo

    This paper describes application system architecture using cellular phones as user interface devices, which enables users to interact with the system by graphic symbols on a client screen. Our approach has the following features: (i) divided interaction logics running on a server and a Java phone client; both interaction logics cooperate to accomplish a user's operation using a simplified script, (ii) local interaction which enables users to handle figures on a client screen without connecting to a server, and (iii) device-independent script which hides the differences of API sets among various cellular phones. By using this architecture, complicated figures including lots of graphic symbols can be displayed in spite of program-size limitation on a client device, and application programs including same interaction logics are just described once for various cellular phones. Our experiments show the advantage of the local interaction. A client program can respond immediately when handling complicated figures. The ratio of requests to the server is reduced to 23%. It takes less than 9 seconds to display typical contents, which is good enough for practical use. This method also reduces development costs at the second development or later.

  7. Study of the redox properties of bismuth-molybdate and uranium-antimonate catalysts

    SciTech Connect

    Paz-Pujalt, G.R.

    1985-01-01

    The oxidation/reduction properties of various bismuth molybdates, molybdenum trioxide, bismuth oxide, uranium antimonate, and iron antimonate have been studied in an effort to correlate them to their catalytic properties. The temperature at which ..gamma..-phase bismuth molybdate is prereduced plays an important role in the behavior the catalyst exhibits under reoxidation conditions. The overall behavior of ..gamma..-phase bismuth molybdate under catalytic conditions may be divided into two temperature regimes: below 360/sup 0/C the catalyst shows a higher rate of propylene adsorption than product desorption, and above 360/sup 0/C where produced desorption is dominant. This temperature is the same at which the Arrhenius plot for the reaction has a break. Several reduction of ..gamma..-bismuth molybdate results in the formation of clusters of bismuth metal and crystallites of molybdenum dioxide. This is irreversible. The reoxidation of the bismuth molybdate catalysts shows the presence of two oxygen incorporation temperatures. The ratios of the areas under these peaks are not the same for the three catalysts. Uranium antimonate shows a lesser degree of lattice oxygen participation. During several reduction the catalyst decomposes partially and an excess of antimony is evident. The isothermal reduction profiles of the catalysts permitted their classification into either of two reduction models: (A) ..cap alpha..-, ..beta..-, ..gamma..-phase bismuth molybdates, molybdenum trioxide, bismuth oxide, and the equimolar mixture follow the nucleation model, (B) uranium antimonate, and iron antimonate following the shrinking sphere model. These models have been correlated to certain characteristics of these catalysts. Group A catalysts show a high degree of lattice oxygen participation (migration of bulk oxygen to surface nuclei). In contrast in group B catalysts only a few layers of oxygen are peeled off during catalysis.

  8. Reducing the consumption of microbead cracking catalyst

    SciTech Connect

    Khadzhiev, S.N.; Rivkinzon, I.B.; Zyuba, B.I.

    1984-05-01

    This article attempts to determine the degree to which catalyst consumption depends on its physicochemical characteristics and on the efficiency of the dust collection systems. As a result of high dust content, catalyst circulation is hindered, uncontrolled chemical conversions in the stagnant zones of the vessels in the reactor section become more of a factor, the content of catalyst dust in the cracked products increases sharply, unfavorable conditions are created for operation of the main distillation tower, and it may be plugged with catalyst dust. The factors that influence the average catalyst consumption in the USSR petroleum refining industry are identified. It is concluded that reliable methods do exist for curtailing catalyst consumption.

  9. 28 CFR 571.52 - Procedures-committed fines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the inmate's commitment, staff shall inform the inmate that there is a committed fine, or fine and... the fine, or fine and costs is paid, except— (i) The inmate may spend money from his/her trust fund.... (b) If the inmate pays the committed fine, or fine and costs, or staff have verified payment,...

  10. Process for gasifying fine grained and dust-like solid fuels

    SciTech Connect

    Dutz, K.; Goeke, E.; Preusser, G.

    1980-06-10

    Fine grained fuel such as coal dust is gasified at an elevated pressure by passing the fuel from a supply tank which is at atmospheric pressure by pump means into a pressurized lock basin and therefrom into the gasifier, the fuel during such movement retaining its loose consistency. This can be accomplished for instance by a solid piston pump which is only partially filled with the fuel. Thus, agglomerations are avoided and the fuel is directly conveyed into the gasifier in flowable and fluidizable form without the necessity of being reconverted into a finely divided form.

  11. Combinatorial methods in catalyst development

    NASA Astrophysics Data System (ADS)

    Lauterbach, Jochen

    2002-03-01

    The discovery of novel catalytic materials has traditionally followed a hypothesize-and-test methodology with limited systematic guidance. In the past few years, a high-throughput approach to catalysis has emerged, which includes efficient sample preparation, parallel processing, and rapid sequential or parallel testing of large diversities of different catalytic materials. A short review of high-throughput screening techniques will be presented. We combine computer-aided materials design techniques with high-throughput screening methodologies for automating and systematizing the catalyst design process. Rapid-scan Fourier transform infrared hyperspectral imaging is used as the main tool for the parallel investigation of multiple member supported catalyst systems. It combines the chemical specificity of infrared spectroscopy with the ability to rapidly analyze multiple samples simultaneously. Using CO oxidation, propylene oxidation, and NO decomposition as model systems, it will be demonstrated that FTIR imaging is well suited to high throughput parallel analysis of reaction products from supported catalyst libraries. A novel, systems-oriented, integrated knowledge architecture that enables the use of high-throughput data for catalyst design will be presented. This new approach involves solving the forward problem of performance prediction using hybrid first principles, rule-based and statistical models and then using that solution to solve the inverse problem: the determination of the optimal catalyst descriptors that meet the target performance.

  12. Immobilized Bis-Indenyl Ligands for Stable and Cost-Effective Metallocene Catalysts of Hydrogenation and Polymerization Reactions

    NASA Astrophysics Data System (ADS)

    Simerly, Thomas Max

    Reactions of catalytic hydrogenations and polymerizations are widely used in industry for manufacture of fine chemicals, pharmaceuticals, and plastics. Homogeneous catalysts for the processes that have low stability and their separation is difficult. Therefore, the development of new highly active and stable catalysts for hydrogenations and polymerizations is a necessity. The objective of this research was the development of a strategy for immobilization of heterogeneous metallocene catalysts. First, a methodology of immobilization of bis-indenyl ligands on the surface of mesoporous silica gel was designed. Four bis-indenyl ligands containing functionalized tethers of various lengths with terminal alkene groups were synthesized. All bis-indenyl ligands were immobilized on the surface of mesoporous functionalized silica gel by two methods: hydrosilylation and thiol-ene coupling of the double bond. After comparing the results, the second strategy was chosen as more efficient. The materials can be used further as intermediates for synthesis of supported metallocene catalysts.

  13. Fused silica fine grinding with low roughness

    NASA Astrophysics Data System (ADS)

    Dai, Lei; Gu, Yongqiang; Wu, Di

    2014-08-01

    Lithography-optics is one of the most complex optical systems. The fine grinding process is the most important step before polishing. Roughness and sub-surface damage (SSD) are essential outputs of fine grinding. We demonstrate the method that use fix abrasive cup tool with CNC grinding machine to complete the fine grinding process, even instead of lapping process. And experiment sample roughness can reach 23.40nm rms and Ra 18.554nm. The SSD estimate is about 2 μm which is also smaller than commercial lapping process. The fine grinding output can satisfy the lithography optic fabrication demands and efficiently reduce the polishing time.

  14. Regeneration of Hydrotreating and FCC Catalysts

    SciTech Connect

    CM Wai; JG Frye; JL Fulton; LE Bowman; LJ Silva; MA Gerber

    1999-09-30

    Hydrotreating, hydrocracking, and fluid catalytic cracking (FCC) catalysts are important components of petroleum refining processes. Hydrotreating and hydrocracking catalysts are used to improve the yield of high-quality light oil fractions from heavier crude oil and petroleum feedstocks containing high levels of impurities. FCC catalysts improve the yield of higher octane gasoline from crude oil. Residuum hydrotreating and cracking catalysts are susceptible to irreversible deactivation caused by adsorption of sulfur and by metals impurities, such as vanadium and nickel. The gradual buildup of these impurities in a hydrotreating catalyst eventually plugs the pores and deactivates it. Nickel and vanadium adversely affect the behavior of cracking catalysts, reducing product yield and quality. Replacing deactivated catalysts represents a significant cost in petroleum refining. Equally important are the costs and potential liabilities associated with treating and disposing spent catalysts. For example, recent US Environmental Protection Agency rulings have listed spent hydrotreating and hydrorefining catalysts as hazardous wastes. FCC catalysts, though more easily disposed of as road-base or as filler in asphalt and cement, are still an economic concern mainly because of the large volumes of spent catalysts generated. New processes are being considered to increase the useful life of catalysts or for meeting more stringent disposal requirements for spent catalysts containing metals. This report discusses a collaborative effort between Pacific Northwest National Laboratory (PNNL) and Phillips Petroleum, Inc., to identify promising chemical processes for removing metals adhered to spent hydrodesulfurization (HDS, a type of hydrotreating catalyst) and FCC catalysts. This study, conducted by PNNL, was funded by the US Department of Energy's Bartlesville Project Office. Fresh and spent catalysts were provided by Phillips Petroleum. The FCC catalyst was a rare-earth exchanged

  15. Molecularly imprinted Ru complex catalysts integrated on oxide surfaces.

    PubMed

    Muratsugu, Satoshi; Tada, Mizuki

    2013-02-19

    Selective catalysis is critical for the development of green chemical processes, and natural enzymes that possess specialized three-dimensional reaction pockets with catalytically active sites represent the most sophisticated systems for selective catalysis. A reaction space in an enzyme consists of an active metal center, functional groups for molecular recognition (such as amino acids), and a surrounding protein matrix to prepare the reaction pocket. The artificial design of such an integrated catalytic unit in a non-enzymatic system remains challenging. Molecular imprinting of a supported metal complex provides a promising approach for shape-selective catalysis. In this process, an imprinted cavity with a shape matched to a template molecule is created in a polymer matrix with a catalytically active metal site. In this Account, we review our studies on molecularly imprinted metal complex catalysts, focusing on Ru complexes, on oxide surfaces for shape-selective catalysis. Oxide surface-attached transition metal complex catalysts not only improve thermal stability and catalyst dispersion but also provide unique catalytic performance not observed in homogeneous precursors. We designed molecularly imprinted Ru complexes by using surface-attached Ru complexes with template ligands and inorganic/organic surface matrix overlayers to control the chemical environment around the active metal complex catalysts on oxide surfaces. We prepared the designed, molecularly imprinted Ru complexes on SiO(2) surfaces in a step-by-step manner and characterized them with solid-state (SS) NMR, diffuse-reflectance (DR) UV-vis, X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller isotherm (BET), X-ray fluorescence (XRF), and Ru K-edge extended X-ray absorption fine structure (EXAFS). The catalytic performances of these Ru complexes suggest that this process of molecular imprinting facilitates the artificial integration of catalytic functions at surfaces. Further advances such

  16. Catalysts for improved fuel processing

    SciTech Connect

    Borup, R.L.; Inbody, M.A.

    2000-09-01

    This report covers our technical progress on fuel processing catalyst characterization for the specific purpose of hydrogen production for proton-exchange-membrane (PEM) fuel cells. These development efforts support DOE activities in the development of compact, transient capable reformers for on-board hydrogen generation starting from candidate fuels. The long-term objective includes increased durability and lifetime, in addition to smaller volume, improved performance, and other specifications required meeting fuel processor goals. The technical barriers of compact fuel processor size, transient capability, and compact, efficient thermal management all are functions of catalyst performance. Significantly, work at LANL now tests large-scale fuel processors for performance and durability, as influenced by fuels and fuel constituents, and complements that testing with micro-scale catalyst evaluation which is accomplished under well controlled conditions.

  17. Catalyst containing oxygen transport membrane

    SciTech Connect

    Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

    2012-12-04

    A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

  18. A Mechanochemically Triggered "Click" Catalyst.

    PubMed

    Michael, Philipp; Binder, Wolfgang H

    2015-11-16

    "Click" chemistry represents one of the most powerful approaches for linking molecules in chemistry and materials science. Triggering this reaction by mechanical force would enable site- and stress-specific "click" reactions--a hitherto unreported observation. We introduce the design and realization of a homogeneous Cu catalyst able to activate through mechanical force when attached to suitable polymer chains, acting as a lever to transmit the force to the central catalytic system. Activation of the subsequent copper-catalyzed "click" reaction (CuAAC) is achieved either by ultrasonication or mechanical pressing of a polymeric material, using a fluorogenic dye to detect the activation of the catalyst. Based on an N-heterocyclic copper(I) carbene with attached polymeric chains of different flexibility, the force is transmitted to the central catalyst, thereby activating a CuAAC in solution and in the solid state. PMID:26420664

  19. Catalyst regeneration with flue gas

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1989-09-19

    This patent describes an integrated once through reactor system for regenerating acidic medium pore zeolite olefin or oxygenate feedstock conversion catalyst with flue gas. It comprises in combination: fluid catalytic cracking catalyst regenerator means for providing the flue gas containing oxygen; at least two fixed bed reactor means for containing the zeolite catalyst, the reactor means receivably connected to the regenerator means for alternately receiving the flue gas therefrom; feedstock conduit means connected to the reactor means for alternately transferring the feedstock thereto; conversion product conduit means receivably connected to the reactor means for alternately transferring the product therefrom; flue gas conduit means receivably connected to the reactor means for alternately transferring flue gas therefrom.

  20. CO2 Hydrogenation over Oxide-Supported PtCo Catalysts: The Role of the Oxide Support in Determining the Product Selectivity.

    PubMed

    Kattel, Shyam; Yu, Weiting; Yang, Xiaofang; Yan, Binhang; Huang, Yanqiang; Wan, Weiming; Liu, Ping; Chen, Jingguang G

    2016-07-01

    By simply changing the oxide support, the selectivity of a metal-oxide catalysts can be tuned. For the CO2 hydrogenation over PtCo bimetallic catalysts supported on different reducible oxides (CeO2 , ZrO2 , and TiO2 ), replacing a TiO2 support by CeO2 or ZrO2 selectively strengthens the binding of C,O-bound and O-bound species at the PtCo-oxide interface, leading to a different product selectivity. These results reveal mechanistic insights into how the catalytic performance of metal-oxide catalysts can be fine-tuned.

  1. Advanced Fine Particulate Characterization Methods

    SciTech Connect

    Steven Benson; Lingbu Kong; Alexander Azenkeng; Jason Laumb; Robert Jensen; Edwin Olson; Jill MacKenzie; A.M. Rokanuzzaman

    2007-01-31

    The characterization and control of emissions from combustion sources are of significant importance in improving local and regional air quality. Such emissions include fine particulate matter, organic carbon compounds, and NO{sub x} and SO{sub 2} gases, along with mercury and other toxic metals. This project involved four activities including Further Development of Analytical Techniques for PM{sub 10} and PM{sub 2.5} Characterization and Source Apportionment and Management, Organic Carbonaceous Particulate and Metal Speciation for Source Apportionment Studies, Quantum Modeling, and High-Potassium Carbon Production with Biomass-Coal Blending. The key accomplishments included the development of improved automated methods to characterize the inorganic and organic components particulate matter. The methods involved the use of scanning electron microscopy and x-ray microanalysis for the inorganic fraction and a combination of extractive methods combined with near-edge x-ray absorption fine structure to characterize the organic fraction. These methods have direction application for source apportionment studies of PM because they provide detailed inorganic analysis along with total organic and elemental carbon (OC/EC) quantification. Quantum modeling using density functional theory (DFT) calculations was used to further elucidate a recently developed mechanistic model for mercury speciation in coal combustion systems and interactions on activated carbon. Reaction energies, enthalpies, free energies and binding energies of Hg species to the prototype molecules were derived from the data obtained in these calculations. Bimolecular rate constants for the various elementary steps in the mechanism have been estimated using the hard-sphere collision theory approximation, and the results seem to indicate that extremely fast kinetics could be involved in these surface reactions. Activated carbon was produced from a blend of lignite coal from the Center Mine in North Dakota and

  2. Catalyst for Decomposition of Nitrogen Oxides

    NASA Technical Reports Server (NTRS)

    Schryer, David R. (Inventor); Jordan, Jeffrey D. (Inventor); Akyurtlu, Ates (Inventor); Akyurtlu, Jale (Inventor)

    2015-01-01

    This invention relates generally to a platinized tin oxide-based catalyst. It relates particularly to an improved platinized tin oxide-based catalyst able to decompose nitric oxide to nitrogen and oxygen without the necessity of a reducing gas.

  3. Novel Fischer-Tropsch catalysts. [DOE patent

    DOEpatents

    Vollhardt, K.P.C.; Perkins, P.

    Novel compounds are described which are used as improved Fischer-Tropsch catalysts particularly for the conversion of CO + H/sub 2/ to gaseous and liquid hydrocarbons at milder conditions than with prior catalysts.

  4. Catalysts for carbon and coal gasification

    DOEpatents

    McKee, Douglas W.; Spiro, Clifford L.; Kosky, Philip G.

    1985-01-01

    Catalyst for the production of methane from carbon and/or coal by means of catalytic gasification. The catalyst compostion containing at least two alkali metal salts. A particulate carbonaceous substrate or carrier is used.

  5. Not Just an Access Issue: Further Analysis of the Digital Divide from a Socioeconomic Perspective

    ERIC Educational Resources Information Center

    Milheim, Karen L.

    2006-01-01

    In recent years, a concern surrounding technology access to historically marginalized populations, referred to as the "Digital Divide" (Divide), has surfaced. This analysis examines the Digital Divide from a socioeconomic standpoint, and discusses the effects of the Divide on students. Also addressed are the varying perspectives towards the…

  6. Bismuth catalysts in aqueous media.

    PubMed

    Kobayashi, Shū; Ueno, Masaharu; Kitanosono, Taku

    2012-01-01

    Several bismuth-catalyzed synthetic reactions, which proceed well in aqueous media, are discussed. Due to increasing demand of water as a solvent in organic synthesis, catalysts that can be used in aqueous media are becoming more and more important. Although bismuth Lewis acids are not very stable in water, it has been revealed that they can be stabilized by basic ligands. Chiral amine and related basic ligands combined with bismuth Lewis acids are particularly useful in asymmetric catalysis in aqueous media. On the other hand, bismuth hydroxide is stable and works as an efficient catalyst for carbon-carbon bond-forming reactions in water. PMID:21769719

  7. The transatlantic divide over brain death determination and the debate.

    PubMed

    Wijdicks, Eelco F M

    2012-04-01

    In 1976, the Royal College of Physicians published neurological criteria of death. The memorandum stated that-after preconditions and exclusion criteria were met-the absence of brainstem function, including apnoea testing, would suffice. In the USA, many experts felt that brain death could be only determined by demonstrating death of the entire brain. In the history of further refinement of UK and USA brain death criteria, one particular period stands out that would bring about an apparent transatlantic divide. On 13 October 1980, the British Broadcasting Corporation aired a programme entitled 'Transplants: Are the Donors Really Dead?' Several United States experts not only disagreed with the United Kingdom criteria, but claimed that patients diagnosed with brain death using United Kingdom criteria could recover. The fallout of this television programme was substantial, as indicated by a media frenzy and a 6-month period of heated correspondence within The Lancet and The British Medical Journal. Members of the Parliament questioned the potential long-term effect on the public's trust in organ transplantation. Given the concerns raised, the British Broadcasting Corporation commissioned a second programme, which was broadcast on 19 February 1981 entitled 'A Question of Life or Death: The Brain Death Debate.' Two panels debated the issues on the accuracy of the electroencephalogram and its place, the absolute need for assessing preconditions before an examination, the problems with recognition of toxins and the feasibility of doing a new prospective study in the United Kingdom, which would follow patients' examination assessed with United Kingdom criteria until cardiac standstill. The positions of the United States and United Kingdom remained diametrically opposed to each other. This article revisits this landmark moment and places it in a wider historical context. In the USA, the focus was not on the brainstem, and the definition of brain death became rapidly infused

  8. Bridging the Divide: Translating Landsat Research Into Usable Science

    NASA Astrophysics Data System (ADS)

    Rocchio, L. E.; Davis, A. L.

    2006-12-01

    Science has long served humankind. Breakthroughs in medicine have increased longevity and advances in technology have made modern-day conveniences possible. Yet, social benefits begotten by the environmental sciences, although critical for the survival of humanity, have not always been as widely recognized or used. To benefit today's rapidly growing population, the divides between environmental research, applied environmental science, and use of this information by decision makers must be bridged. Lessons about the translation from research to usable science can be learned from the four decades of Landsat history, and these lessons can serve as useful models for bridging the gaps between new technology, scientific research, and the use of that research and technology in real-world problem solving. In 1965, William Pecora, then-director of the U.S. Geological Survey, proposed the idea of a remote sensing satellite program to gather facts about natural resources of Earth. For the next seven years, an intense campaign showing the depth and diversity of satellite imagery applications was waged. This led to the 1972 launch of the first civilian land-observing satellite, Landsat 1. By 1975, successful application research based on Landsat 1 imagery prompted then-NASA Administrator Dr. James Fletcher to proclaim that if one space age development would save the world, it would be Landsat and its successor satellites. Thirty-four years of continual Landsat imaging and related-research has lead to the implementation of many socially beneficial applications, such as improved water management techniques, crop insurance fraud reduction, illicit crop inventories, natural disaster relief planning, continent-scale carbon estimates, and extensive cartographic advances. Despite these successes, the challenge of translating Landsat research into realized social benefits remains. Even in this geospatially-savvy era, the utility of Landsat largely escapes policymakers. Here, in an

  9. Correlating Extent of Pt–Ni Bond Formation with Low-temperature Hydrogenation of Benzene and 1,3-butadiene over Supported Pt/Ni Bimetallic Catalysts

    SciTech Connect

    Lonergan, W.; Vlachos, D; Chen, J

    2010-01-01

    Low-temperature hydrogenation of benzene and 1,3-butadiene on supported Pt/Ni catalysts have been used as probe reactions to correlate hydrogenation activity with the extent of Pt-Ni bimetallic bond formation. Pt/Ni bimetallic and Pt and Ni monometallic catalysts were supported on {gamma}-Al{sub 2}O{sub 3} using incipient wetness impregnation. Two sets of bimetallic catalysts were synthesized: one set to study the effect of metal atomic ratio and the other to study the effect of impregnation sequence. Fourier transform infrared spectroscopy (FTIR) CO adsorption studies were performed to characterize the surface composition of the bimetallic nanoparticles, and transmission electron microscopy (TEM) was utilized to characterize the particle size distribution. Batch reactor studies with FTIR demonstrated that all bimetallic catalysts outperformed monometallic catalysts for both benzene and 1,3-butadiene hydrogenation. Within the two sets of bimetallic catalysts, it was found that catalysts with a smaller Pt:Ni ratio possessed higher hydrogenation activity and that catalysts synthesized using co-impregnation had greater activity than sequentially impregnated catalysts. Extended X-ray absorption fine structure (EXAFS) measurements were performed in order to verify the extent of Pt-Ni bimetallic bond formation, which was found to correlate with the hydrogenation activity.

  10. On-line regeneration of hydrodesulfurization catalyst

    DOEpatents

    Preston, Jr., John L.

    1980-01-01

    A hydrotreating catalyst is regenerated as it concurrently hydrotreats a hydrocarbon fuel by introducing a low concentration of oxygen into the catalyst bed either continuously or periodically. At low oxygen concentrations the carbon deposits on the catalyst are burned off without harming the catalyst and without significantly affecting the hydrotreating process. In a preferred embodiment the hydrotreating process is hydrodesulfurization, and regenerating is done periodically with oxygen concentrations between 0.1 and 0.5 volume percent.

  11. Controlled Surface Segregation Leads to Efficient Coke-Resistant Nickel/Platinum Bimetallic Catalysts for the Dry Reforming of Methane

    SciTech Connect

    Li, Lidong; Zhou, Lu; Ould-Chikh, Samy; Anjum, Dalaver H.; Kanoun, Mohammed B.; Scaranto, Jessica; Hedhili, Mohamed N.; Khalid, Syed; Laveille, Paco V.; Lawrence D'Souza; Clo, Alain; Basset, Jean-Marie

    2015-02-03

    The surface composition and structure are of vital importance for heterogeneous catalysts, especially for bimetallic catalysts, which often vary as a function of reaction conditions (known as surface segregation). The preparation of bimetallic catalysts with controlled metal surface composition and structure is very challenging. In this study, we synthesize a series of Ni/Pt bimetallic catalysts with controlled metal surface composition and structure using a method derived from surface organometallic chemistry. Moreover, the evolution of the surface composition and structure of the obtained bimetallic catalysts under simulated reaction conditions is investigated by various techniques, which include CO-probe IR spectroscopy, high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, extended X-ray absorption fine structure analysis, X-ray absorption near-edge structure analysis, XRD, and X-ray photoelectron spectroscopy. It is demonstrated that the structure of the bimetallic catalyst is evolved from Pt monolayer island-modified Ni nanoparticles to core–shell bimetallic nanoparticles composed of a Ni-rich core and a Ni/Pt alloy shell upon thermal treatment. The catalysts are active for the dry reforming of methane, and their catalytic activities, stabilities, and carbon formation vary with their surface composition and structure.

  12. SOUTHERN FINE PARTICULATE MONITORING PROJECT

    SciTech Connect

    Ashley D. Williamson

    2001-10-01

    This quarterly report presents results and analysis of continuous onsite ambient fine particulate data at the North Birmingham study site during the July-September, 2000 study period. The continuous data include PM{sub 2.5} mass concentrations measured by TEOM, particle sulfate using the R&P 8400S sulfate monitor, particle size distributions measured by SMPS and APS monitors, and PM{sub 2.5} light scattering extinction coefficient as measured by nephelometer. The report also presents some initial notes on our operating experience with the 8400S sulfate analyzer. As described in the previous quarterly report, some persistent daily trends are seen in the particulate data, superimposed on a seasonal trend toward higher concentrations in warmer months. The sulfate mass fraction shows a markedly different time of day pattern from the balance of the particle mass, confirming the independent origin of this major mass fraction. The time variability of the major mass-bearing size fractions, and of the light-scattering potential, do not allow for a clean separation of independent size fractions. However, when the particle number averages are examined, the stronger time of day dependence of the smaller size fractions becomes more apparent, consistent with periods of higher formation of sub-100nm particles in early morning and in afternoon-evening periods.

  13. [The role of fine-needle aspiration in the diagnosis of thyroid nodules].

    PubMed

    Marrazzo, Antonio; Casà, Luigi; David, Massimo; Lo Gerfo, Domenico; Noto, Antonio; Taormina, Piera

    2005-01-01

    The aim of this study was to prospectively evaluate the sensitivity, specificity and accuracy of fine-needle aspiration of thyroid nodules. From January 1978 to December 2003, 497 patients underwent fine-needle aspiration of thyroid nodules and then thyroidectomy. Fine-needle aspiration was performed with a fine 23-25 gauge and the aspirate was fixed and dyed with May-Grounwald-Giemsa method. The results of cytology were divided into four groups: positive for malignancy (77 patients), negative for malignancy (370 patients), suspect for malignancy (34 patients) and not diagnostic (16 patients). Suspect specimens also included follicular neoplasm and Hürthle cell neoplasm. Fine-needle aspiration results were compared with histopathologic analysis after thyroidectomy. There were 2 false-positive (0.5%) and 5 false-negative patients (1%). Sensitivity, specificity and accuracy were respectively 94.7%, 99% and 98.4%. This study confirms that fine-needle aspiration of thyroid nodules can be performed easily with high sensitivity, specificity and accuracy. PMID:15832740

  14. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    DOEpatents

    Gangwal, S.; Jothimurugesan, K.

    1999-07-27

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption process, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gases from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or passivating the heavy metals on the spent FCC catalyst as an intermediate step.

  15. Attrition resistant catalysts and sorbents based on heavy metal poisoned FCC catalysts

    DOEpatents

    Gangwal, Santosh; Jothimurugesan, Kandaswamy

    1999-01-01

    A heavy metal poisoned, spent FCC catalyst is treated by chemically impregnating the poisoned catalyst with a new catalytic metal or metal salt to provide an attrition resistant catalyst or sorbent for a different catalytic or absorption processes, such as catalysts for Fischer-Tropsh Synthesis, and sorbents for removal of sulfur gasses from fuel gases and flue-gases. The heavy metal contaminated FCC catalyst is directly used as a support for preparing catalysts having new catalytic properties and sorbents having new sorbent properties, without removing or "passivating" the heavy metals on the spent FCC catalyst as an intermediate step.

  16. Get out of Fines Free: Recruiting Student Usability Testers via Fine Waivers

    ERIC Educational Resources Information Center

    Hockenberry, Benjamin; Blackburn, Kourtney

    2016-01-01

    St. John Fisher College's Lavery Library's Access Services and Systems departments began a pilot project in which students with overdue fines tested usability of library Web sites in exchange for fine waivers. Circulation staff promoted the program and redeemed fine waiver vouchers at the Checkout Desk, while Systems staff administered testing and…

  17. ADVANCING FINE ROOT RESEARCH WITH MINIRHIZOTRONS

    EPA Science Inventory

    Minirhizotrons provide a nondestructive, in situ method for directly viewing and studying fine roots. Although many insights into fine roots have been gained using minirhizotrons, it is clear from the literature that there is still wide variation in how minirhizotrons and minirhi...

  18. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  19. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  20. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  1. Sulfate as a precursor of catalyst poisoning

    SciTech Connect

    Mador, I.L.; Rosan, A.M.; Crissey, R.K.

    1984-05-01

    The poisoning of noble metal catalysts of hydrogenation reactions by sulfur in various forms is discussed. The specific reaction investigated was the hydrogenation of phenol to cyclohexanone over palladium. Catalyst pretreatments with NaHSO/sub 4/, PdSO/sub 4/, H/sub 2/, and He produced catalyst activities varying from inactive to unimpaired.

  2. Silver doped catalysts for treatment of exhaust

    DOEpatents

    Park, Paul Worn; Hester, Virgil Raymond; Ragle, Christie Susan; Boyer, Carrie L.

    2009-06-02

    A method of making an exhaust treatment element includes washcoating a substrate with a slurry that includes a catalyst support material. At least some of the catalyst support material from the slurry may be transferred to the substrate, and silver metal (Ag) is dispersed within the catalyst support material.

  3. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  4. 40 CFR 721.9665 - Organotin catalysts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853,...

  5. Regeneration of Hydrotreating and FCC Catalysts

    SciTech Connect

    Gerber, Mark A.; Frye, John G.; Bowman, Lawrence E.; Fulton, John L.; Silva, Laura J.; Wai, Chien M.

    1999-09-30

    Hydrotreating, hydrocracking, and fluid catalytic cracking (FCC) catalysts are important components of petroleum refining processes. Hydrotreating and hydrocracking catalysts are used to improve the yield of high-quality light oil fractions from heavier crude oil and petroleum feedstocks containing high levels of impurities. FCC catalysts improve the yield of higher octane gasoline from crude oil.

  6. Highly dispersed catalysts for coal liquefaction

    SciTech Connect

    Hirschon, A.S.; Wilson, R.B.

    1992-11-05

    The objectives of this project are to study the effect of pretreatment methods on the two-stage liquefaction process. In particular, the effects of dispersed catalysts and carbon monoxide atmospheres on a coal liquefaction process. The project is divided into three technical tasks. Task 1 and 2 deal with the analyses and liquefaction experiments, respectively, whereas Task 3 deals with the economic impact of utilizing the pretreatment methods. This quarter we concentrated on Tasks 1 and 2, which are summarized below. Samples of Black Thunder Subbituminous coal and the corresponding recycle solvent were received from Wilsonville. These particular samples were obtained from run [number sign]263. The samples were analyzed for a proximate and ultimate analysis, as well as heat content. We have also received samples of the iron oxide used in the Wilsonville coal liquefaction runs as well as Shell 324 and molyVanL for use in future runs. Base-line screening experiments were conducted in 300 mL autoclaves using 2.5 parts by weight of recycle solvent to 1 part Black Thunder coal at 425[degree]C for one hour. In preliminary results for the comparison of iron oxide and iron carbonyl, the iron carbonyl appears to give higher yields to soluble products.

  7. Catalysts for coal liquefaction processes

    DOEpatents

    Garg, D.

    1986-10-14

    Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

  8. Catalyst. Issue 2, Fall 2008

    ERIC Educational Resources Information Center

    Hawkins, B. Denise, Ed.

    2008-01-01

    Catalyst, a quarterly newsletter from the Institute's Communications Office, contains news, information, and features about the programs and services of the National Institute for Literacy. Contents of this issue include: (1) Shanahan on the National Early Literacy Panel Report: What's in Store; (2) Director's Message; (3) Representative Fattah to…

  9. Catalyst. Issue 1, Spring 2008

    ERIC Educational Resources Information Center

    Hawkins, B. Denise, Ed.

    2008-01-01

    Catalyst, a quarterly newsletter from the Institute's Communications Office, contains news, information, and features about the programs and services of the National Institute for Literacy. This issue contains the following articles: (1) Spanish-Language Publication for Parents of Young Readers Among the Institute's New Titles; (2) Director's…

  10. Perovskite catalysts for oxidative coupling

    DOEpatents

    Campbell, K.D.

    1991-06-25

    Perovskites of the structure A[sub 2]B[sub 2]C[sub 3]O[sub 10] are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  11. Perovskite catalysts for oxidative coupling

    DOEpatents

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  12. Coal liquefaction with molybdenum catalysts

    SciTech Connect

    Chien, P.L.

    1983-01-01

    Coal liquefaction experiments were carried out in a stirred autoclave under nitrogen. Tetralin was employed as solvent, and the catalyst, when used, was ammonium heptamolybdate (impregnated on coal) or stannous chloride (powdered). Production of pentane soluble oil was higher in the runs with catalyst, but net hydrogen transfer from tetralin to coal was less when catalyst was used. Coal and powdered stannous chloride exhibited a marked synergistic effect on the dehydrogenation of tetralin. A free radical mechanism was suggested to explain this effect, and model experiments with bibenzyl (but no coal) gave results that were consistent with this mechanism. An apparent synergistic effect of coal and impregnated ammonium heptamolybdate was shown to be attributed simply to improved distribution (higher surface area) of the impregnated catalyst, the coal acting as a high-area support. Comparison of the results from autoclave experiments (under nitrogen) with those from tubing bomb experiments (under air) indicated major differences in coal conversion and hydrogen transfer. The conversion was 62% in the autoclave and 81% in the tubing bomb, and the hydrogen transfer was 0.7% in the autoclave and 2.93% in the tubing bomb, when 1% of Mo (based on coal) was impregnated on coal in a preliminary step.

  13. Catalysts for coal liquefaction processes

    DOEpatents

    Garg, Diwakar

    1986-01-01

    Improved catalysts for catalytic solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprise a combination of zinc or copper, or a compound thereof, and a Group VI or non-ferrous Group VIII metal, or a compound thereof.

  14. Pulmonary Fibrosis in Workers Exposed to Finely Powdered Aluminium

    PubMed Central

    Mitchell, John; Manning, G. B.; Molyneux, M.; Lane, Ronald E.

    1961-01-01

    Of 30 workmen at risk 27 were examined and six found to have evidence of pulmonary fibrosis. In the two fatal cases the evidence for pulmonary fibrosis was conclusive and in three other cases it was sufficient; in one case it was suggestive. The clinical, radiological, and pathological features of these six cases are recorded. Results of respiratory function tests on the four non-fatal cases are given. The manufacturing process is described. An analysis of the powder is given, also the results of dust measurement in the contaminated atmosphere. The literature is reviewed and our own experience compared with reports from Germany and Canada. We concluded that the pulmonary fibrosis was caused by the dust inhaled at work and that the component responsible was finely divided aluminium. Images PMID:13771334

  15. Structural and Electrocatalytic Properties of PtIrCo/C Catalysts for Oxygen Reduction Reaction

    SciTech Connect

    Loukrakpam, Rameshwori; Wanjala, Bridgid N.; Yin, Jun; Fang, Bin; Luo, Jin; Shao, Minhua; Protsailo, Lesia; Kawamura, Tetsuo; Chen, Yongsheng; Petkov, Valeri; Zhong, Chuan-Jian

    2015-10-15

    This paper describes the results of an investigation of the synthesis of PtIrCo nanoparticles (2-3 nm) for electrocatalytic oxygen reduction reaction. The carbon-supported PtIrCo catalysts (PtIrCo/C) were thermally treated at temperatures ranging from 400 to 900 C. The size, composition, and atomic-scale structures of the PtIrCo/C catalysts were characterized for establishing their correlation with the electrocatalytic activity toward oxygen reduction reaction. The specific activity was found to increase by a factor of 3-5 for the PtIrCo/C catalysts in comparison with Pt/C catalysts. A correlation was identified between the specific activity and the nanoparticle's fcc-type lattice parameter. The specific activity increases whereas the fcc-type lattice parameter decreases with the thermal treatment temperature. This correlation was further substantiated by analyzing the interatomic spatial parameters in the trimetallic nanoparticles based on X-ray absorption fine structure spectroscopic and high-energy XRD experiments. Implications of these findings, along with the durability of the catalysts, to the design of active electrocatalysts were also discussed.

  16. Studies on KIT-6 Supported Cobalt Catalyst for Fischer–Tropsch Synthesis

    SciTech Connect

    Gnanamani, M.; Jacobs, G; Graham, U; Ma, W; Pendyala, V; Ribeiro, M; Davis, B

    2010-01-01

    KIT-6 molecular sieve was used as a support to prepare cobalt catalyst for Fischer-Tropsch synthesis (FTS) using an incipient wetness impregnation method to produce cobalt loadings of 15 and 25 wt%. The catalysts were characterized by BET surface area, X-ray diffraction, scanning transmission election microscopy (STEM), extended X-ray absorption fine spectroscopy and X-ray absorption near edge spectroscopy. The catalytic properties for FTS were evaluated using a 1L CSTR reactor. XRD, pore size distribution, and STEM analysis indicate that the KIT-6 mesostructure remains stable during and after cobalt impregnation and tends to form smaller cobalt particles, probably located inside the mesopores. The mesoporous KIT-6 exhibited a slightly higher cobalt dispersion compared to amorphous SiO{sub 2} supported catalyst. With the higher Co loading (25 wt%) on KIT-6, partial structural collapse was observed after the FTS reaction. Compared to an amorphous SiO{sub 2} supported cobalt catalyst, KIT-6 supported cobalt catalyst displayed higher methane selectivity at a similar Co loading, likely due to diffusion effects.

  17. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    SciTech Connect

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2004-03-31

    In this reporting period, a fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of production since the reaction is highly exothermic. Consequently, heavy wax products must be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase FTS. The separation problem is further compounded by catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. Existing pilot-scale equipment was modified to include a filtration test apparatus. After undergoing an extensive plant shakedown period, filtration tests with cross-flow filter modules using simulant FTS wax slurry were conducted. The focus of these early tests was to find adequate mixtures of polyethylene wax to simulate FTS wax. Catalyst particle size analysis techniques were also developed. Initial analyses of the slurry and filter permeate particles will be used by the research team to design improved filter media and cleaning strategies.

  18. The Different Impacts of SO2 and SO3 on Cu/zeolite SCR Catalysts

    SciTech Connect

    Cheng, Y.; Lambert, C; Kim, D; Kwak, J; Cho, S; Peden, C

    2010-01-01

    The different impacts of SO{sub 2} and SO{sub 3} on Cu/zeolite SCR catalysts were investigated by SCR performance tests and multiple characterization techniques including temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS). The results indicate that a larger amount of highly dispersed CuSO{sub 4} formed in the zeolite catalysts (Z-CuSO{sub 4}) upon SO{sub 3} poisoning, explaining the much more significant deactivation of the Cu/zeolite catalysts that were exposed to SO{sub 3} compared to poisoning by SO{sub 2}. This paper provides the first demonstration that active sites of Cu/zeolite SCR catalysts involved in the storage and removal of sulfur can react with SO{sub 2} and SO{sub 3} in very different ways. In particular, the significant differences in the extent of sulfur uptake account for the considerably different impacts of SO{sub 2} and SO{sub 3} poisoning on the performance of Cu/zeolite SCR catalysts.

  19. The Different Impacts of SO2 and SO3 on Cu/Zeolite SCR Catalysts

    SciTech Connect

    Cheng, Yisun; Lambert, Christine; Kim, Do Heui; Kwak, Ja Hun; Cho, Sung June; Peden, Charles HF

    2010-06-19

    The different impacts of SO2 and SO3 on Cu/zeolite SCR catalysts were investigated by SCR performance tests and multiple characterization techniques including temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS). The results indicate that a larger amount of highly dispersed CuSO4 formed in the zeolite catalysts (Z-CuSO4) upon SO3 poisoning, explaining the much more significant deactivation of the Cu/zeolite catalysts that were exposed to SO3 compared to poisoning by SO2. This paper provides the first demonstration that active sites of Cu/zeolite SCR catalysts involved in the storage and removal of sulfur can react with SO2 and SO3 in very different ways. In particular, the significant differences in the extent of sulfur uptake account for the considerably different impacts of SO2 and SO3 poisoning on the performance of Cu/zeolite SCR catalysts.

  20. An evaluation of Pt sulfite acid (PSA) as precursor for supported Pt catalysts

    SciTech Connect

    Regalbuto, J.R.; Ansel, O.; Miller, J.T.

    2010-11-12

    As a catalyst precursor, platinum sulfite acid (PSA) is easy to use and not relatively expensive, and is a potentially attractive precursor for many types of supported catalysts. The ultimate usefulness for many catalyst applications will depend on the extent that Pt can be dispersed and sulfur eliminated. To our knowledge, there exists no detailed characterization in the catalysis literature of PSA and the nanoparticulate Pt phases derived from it during catalyst pretreatment. To this end a series of supports including alumina, silica, magnesia, niobia, titania, magnesia and carbon were contacted with PSA solutions and subsequently analyzed with extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) analysis, and x-ray photoelectron spectroscopy (XPS) to characterize the Pt species formed upon impregnation, calcination, and reduction. While all catalysts show retention of some S, reasonably small particle sizes with relatively little Pt-S can in some instances be produced using PSA. The amount of retained sulfur appears to decrease with decreasing surface acidity, although even the most acidic supports (niobia and silica) display some storage of S even while only Pt-O bands are observed after calcination or reoxidation. More sulfur was eliminated by high temperature calcinations followed by reduction in hydrogen, at the expense of increasing Pt particle size.

  1. Upgrading light olefin fuel gas and catalytic reformate in a turbulent fluidized bed catalyst reactor

    SciTech Connect

    Kushnerick, J.D.; Harandi, M.N.; Owen, H.

    1989-05-02

    A fluidized bed catalyst process is described for conversion of C/sub 4/- light olefinic gas feedstock to C/sub 5/+ hydrocarbons and for conversion of C/sub 6/ to C/sub 8/ aromatic feedstock to C/sub 7/ to C/sub 11/ aromatics. It consists of: maintaining a fluidized bed of zeolite catalyst particles in a turbulent reactor bed at a temperature of about 500/sup 0/ to 800/sup 0/F, the catalyst having an apparent particle density of about 0.9 to 1.6 g/cm/sup 3/ and a size range of about 1 to 150 microns, an average catalyst particle size of about 20 to 100 microns containing about 10 to 25 weight percent of fine particles having a particle size less than 32 microns; contacting the feedstocks and passing the feedstocks upwardly through the fluidized catalyst bed under turbulent flow conditions at reaction conditions sufficient to convert at least about 70% of the olefin feedstock and to convert at least 5% of the C/sub 6/ to C/sub 8/ aromatic feedstock; maintaining turbulent fluidized bed conditions through the reactor bed between transition velocity and transport velocity at a superficial fluid velocity of about 0.3 to 2 meters per second; and recovering hydrocarbon product containing C/sub 5/+ hydrocarbons C/sub 7/ to C/sub 11/ aromatic hydrocarbons.

  2. Toward Molecular Catalysts by Computer

    SciTech Connect

    Raugei, Simone; DuBois, Daniel L.; Rousseau, Roger J.; Chen, Shentan; Ho, Ming-Hsun; Bullock, R. Morris; Dupuis, Michel

    2015-02-17

    Rational design of molecular catalysts requires a systematic approach to designing ligands with specific functionality and precisely tailored electronic and steric properties. It then becomes possible to devise computer protocols to predict accurately the required properties and ultimately to design catalysts by computer. In this account we first review how thermodynamic properties such as oxidation-reduction potentials (E0), acidities (pKa), and hydride donor abilities (ΔGH-) form the basis for a systematic design of molecular catalysts for reactions that are critical for a secure energy future (hydrogen evolution and oxidation, oxygen and nitrogen reduction, and carbon dioxide reduction). We highlight how density functional theory allows us to determine and predict these properties within “chemical” accuracy (~ 0.06 eV for redox potentials, ~ 1 pKa unit for pKa values, and ~ 1.5 kcal/mol for hydricities). These quantities determine free energy maps and profiles associated with catalytic cycles, i.e. the relative energies of intermediates, and help us distinguish between desirable and high-energy pathways and mechanisms. Good catalysts have flat profiles that avoid high activation barriers due to low and high energy intermediates. We illustrate how the criterion of a flat energy profile lends itself to the prediction of design points by computer for optimum catalysts. This research was carried out in the Center for Molecular Electro-catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory (PNNL) is operated for the DOE by Battelle.

  3. Microbial recovery of metals from spent catalysts

    SciTech Connect

    Sperl, P.L.; Sperl, G.T.

    1990-01-01

    This project was initiated on October 1, 1989, for the purpose of recovering metals from spent coal liquefaction catalysts. Two catalyst types are the subject of the contract. The first is a Ni-Mo catalyst supported on alumina (Shell 324) as is used in a pilot scale coal liquefaction facility at Wilsonville, Alabama. The object of the contract is to treat these spent catalysts with microorganisms, especially Thiobacillus ferrooxidans, but also other Thiobacillus sp., to leach and remove the metals (Ni and Mo) from the spent catalysts into a form which can be readily recovered by conventional techniques.

  4. The History of Current State of the Art of Propylene Polymerization Catalysts.

    ERIC Educational Resources Information Center

    Goodall, Brian L.

    1986-01-01

    Outlines the development of the modern catalysts for propylene polymerization, considering the historical background; structure of titanium chloride catalysts; first-generation catalysts; cocatalysts; second-generation catalysts; catalysts morphology; and third-generation (supported catalysts). (JN)

  5. Synthesis and characterization of supported sugar catalyst by dip coating method

    NASA Astrophysics Data System (ADS)

    Janaun, J.; Siambun, N. J.; Safie, N. N.

    2016-06-01

    Sugar catalyst is a novel solid acid catalyst with reactivity comparable to that of sulphuric acid in biodiesel production. However, the fine powder form of sugar catalyst with the non-porous structure might cause large pressure drop in a packed bed reactor due to low bed porosity, affecting the reaction conversion especially in gas phase reaction. Furthermore, higher pressure drop requires higher electrical energy to drive the fluid through. Increasing the particle size is anticipated to be able to overcome the pressure drop matter. Hence, a deposition of sugar catalyst on larger particle materials was studied. Three types of materials were used for this investigation namely aluminum, silica and clay. The deposition was done via dip-coating method. The materials were characterized for their total acidity, thermal stability, functional groups, surface area, and element composition. The total acidity for SCDCAl, SCDCSi, and SCDCCl were 0.9 mmol/g, 0.2 mmol/g, and 0.4 mmol/g, respectively. The ratio of char deposited on SCDCAl, SCDCSi and SCDCCl were 0.9 g of support/g of carbon, 0.040 g of support/g of carbon, and 0.014 g of support/g of carbon respectively. FTIR and EDX analyses were carried out to determine the presence of active sites of the catalysis by identifying the functional groups such as -COOH, -OH, -SO3H. The results showed that -SO3H was detected on the surface of synthesized catalysts, except for SCDCC1.The pore size of SCDCAl, SCDCSi and SCDCCl were classified as macropores because the average diameter were greater than 50nm.. The catalysts were stable up to 400°C. The results showed that the dipcoating method could deposit sugar catalyst on aluminum, silica, and clay at low total acidity concentration.

  6. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    SciTech Connect

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2005-03-31

    In this reporting period, a fundamental filtration study was continued to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. In this reporting period, a series of crossflow filtration experiments were initiated to study the effect of olefins and oxygenates on the filtration flux and membrane performance. Iron-based FTS reactor waxes contain a significant amount of oxygenates, depending on the catalyst formulation and operating conditions. Mono-olefins and aliphatic alcohols were doped into an activated iron catalyst slurry (with Polywax) to test their influence on filtration properties. The olefins were varied from 5 to 25 wt% and oxygenates from 6 to 17 wt% to simulate a range of reactor slurries reported in the literature. The addition of an alcohol (1-dodecanol) was found to decrease the permeation rate while the olefin added (1-hexadecene) had no effect on the permeation rate. A passive flux maintenance technique was tested that can temporarily increase the permeate rate for 24 hours.

  7. Fine Guidance Sensing for Coronagraphic Observatories

    NASA Technical Reports Server (NTRS)

    Brugarolas, Paul; Alexander, James W.; Trauger, John T.; Moody, Dwight C.

    2011-01-01

    Three options have been developed for Fine Guidance Sensing (FGS) for coronagraphic observatories using a Fine Guidance Camera within a coronagraphic instrument. Coronagraphic observatories require very fine precision pointing in order to image faint objects at very small distances from a target star. The Fine Guidance Camera measures the direction to the target star. The first option, referred to as Spot, was to collect all of the light reflected from a coronagraph occulter onto a focal plane, producing an Airy-type point spread function (PSF). This would allow almost all of the starlight from the central star to be used for centroiding. The second approach, referred to as Punctured Disk, collects the light that bypasses a central obscuration, producing a PSF with a punctured central disk. The final approach, referred to as Lyot, collects light after passing through the occulter at the Lyot stop. The study includes generation of representative images for each option by the science team, followed by an engineering evaluation of a centroiding or a photometric algorithm for each option. After the alignment of the coronagraph to the fine guidance system, a "nulling" point on the FGS focal point is determined by calibration. This alignment is implemented by a fine alignment mechanism that is part of the fine guidance camera selection mirror. If the star images meet the modeling assumptions, and the star "centroid" can be driven to that nulling point, the contrast for the coronagraph will be maximized.

  8. Perspectives of Using Ultra-Fine Metals as Universal Safe BioStimulators to Get Cattle Breeding Quality Products

    NASA Astrophysics Data System (ADS)

    Polishchuk, S.

    2015-11-01

    We have conducted investigations of ultra-fine metals biological activity with lab non-pedigree white rats, rabbits breed “Soviet chinchilla” and cattle young stock of the black and white breed as the most widely spread in the central part of Russia. One can see the possibility of using microelements of ultra-fine iron, cobalt and copper as cheap, non-toxic and highly effective biological catalyst of biochemical processes in the organism that improve physiological state, morphological and biochemical blood parameters increasing activity of the experimental animals’ ferment systems and their productivity and meat biological value. We have proved the ultra-fine powders safety when adding them to the animals’ diet.

  9. Autothermal reforming catalyst having perovskite structure

    DOEpatents

    Krumpel, Michael; Liu, Di-Jia

    2009-03-24

    The invention addressed two critical issues in fuel processing for fuel cell application, i.e. catalyst cost and operating stability. The existing state-of-the-art fuel reforming catalyst uses Rh and platinum supported over refractory oxide which add significant cost to the fuel cell system. Supported metals agglomerate under elevated temperature during reforming and decrease the catalyst activity. The catalyst is a perovskite oxide or a Ruddlesden-Popper type oxide containing rare-earth elements, catalytically active firs row transition metal elements, and stabilizing elements, such that the catalyst is a single phase in high temperature oxidizing conditions and maintains a primarily perovskite or Ruddlesden-Popper structure under high temperature reducing conditions. The catalyst can also contain alkaline earth dopants, which enhance the catalytic activity of the catalyst, but do not compromise the stability of the perovskite structure.

  10. Semisynthetic and Biomolecular Hydrogen Evolution Catalysts.

    PubMed

    Kandemir, Banu; Chakraborty, Saikat; Guo, Yixing; Bren, Kara L

    2016-01-19

    There has been great interest in the development of stable, inexpensive, efficient catalysts capable of reducing aqueous protons to hydrogen (H2), an alternative to fossil fuels. While synthetic H2 evolution catalysts have been in development for decades, recently there has been great progress in engineering biomolecular catalysts and assemblies of synthetic catalysts and biomolecules. In this Forum Article, progress in engineering proteins to catalyze H2 evolution from water is discussed. The artificial enzymes described include assemblies of synthetic catalysts and photosynthetic proteins, proteins with cofactors replaced with synthetic catalysts, and derivatives of electron-transfer proteins. In addition, a new catalyst consisting of a thermophilic cobalt-substituted cytochrome c is reported. As an electrocatalyst, the cobalt cytochrome shows nearly quantitative Faradaic efficiency and excellent longevity with a turnover number of >270000.

  11. Cationic ruthenium alkylidene catalysts bearing phosphine ligands.

    PubMed

    Endo, Koji; Grubbs, Robert H

    2016-02-28

    The discovery of highly active catalysts and the success of ionic liquid immobilized systems have accelerated attention to a new class of cationic metathesis catalysts. We herein report the facile syntheses of cationic ruthenium catalysts bearing bulky phosphine ligands. Simple ligand exchange using silver(i) salts of non-coordinating or weakly coordinating anions provided either PPh3 or chelating Ph2P(CH2)nPPh2 (n = 2 or 3) ligated cationic catalysts. The structures of these newly reported catalysts feature unique geometries caused by ligation of the bulky phosphine ligands. Their activities and selectivities in standard metathesis reactions were also investigated. These cationic ruthenium alkylidene catalysts reported here showed moderate activity and very similar stereoselectivity when compared to the second generation ruthenium dichloride catalyst in ring-closing metathesis, cross metathesis, and ring-opening metathesis polymerization assays.

  12. Selectivity, activity, and metal-support interactions of Rh bimetallic catalysts. Progress report, 15 November 1981-15 August 1982

    SciTech Connect

    Haller, G L

    1982-08-01

    We report on a detailed investigation of the effect of TiO/sub 2/ support on Rh-Ag interaction as exhibited in catalytic activity. The temporal evolution of activity over Rh-Ag/TiO/sub 2/ for ethane hydrogenolysis and hydrogen chemisorption as a function of temperature, Ag to Rh ratio, the Rh particle size, Rh loading, and ambient gas were studied. Preliminary extended x-ray absorption fine structure (EXAFS) analysis of Rh/TiO/sub 2/ catalysts indicate that 100% exposed (dispersed) catalyst prepared by ion exchange may be atomically dispersed after low temperature reduction. 7 figures, 1 table.

  13. Dividers for reduction of aerodynamic drag of vehicles with open cavities

    NASA Technical Reports Server (NTRS)

    Storms, Bruce L. (Inventor)

    2007-01-01

    A drag-reduction concept for vehicles with open cavities includes dividing a cavity into smaller adjacent cavities through installation of one or more vertical dividers. The dividers may extend the full depth of the cavity or only partial depth. In either application, the top of the dividers are typically flush with the top of the bed or cargo bay of the vehicle. The dividers may be of any material, but are strong enough for both wind loads and forces encountered during cargo loading/unloading. For partial depth dividers, a structural angle may be desired to increase strength.

  14. Catalyst for Carbon Monoxide Oxidation

    NASA Technical Reports Server (NTRS)

    Davis, Patricia; Brown, Kenneth; VanNorman, John; Brown, David; Upchurch, Billy; Schryer, David; Miller, Irvin

    2010-01-01

    In many applications, it is highly desirable to operate a CO2 laser in a sealed condition, for in an open system the laser requires a continuous flow of laser gas to remove the dissociation products that occur in the discharge zone of the laser, in order to maintain a stable power output. This adds to the operating cost of the laser, and in airborne or space applications, it also adds to the weight penalty of the laser. In a sealed CO2 laser, a small amount of CO2 gas is decomposed in the electrical discharge zone into corresponding quantities of CO and O2. As the laser continues to operate, the concentration of CO2 decreases, while the concentrations of CO and O2 correspondingly increase. The increasing concentration of O2 reduces laser power, because O2 scavenges electrons in the electrical discharge, thereby causing arcing in the electric discharge and a loss of the energetic electrons required to boost CO2 molecules to lasing energy levels. As a result, laser power decreases rapidly. The primary object of this invention is to provide a catalyst that, by composition of matter alone, contains chemisorbed water within and upon its structure. Such bound moisture renders the catalyst highly active and very long-lived, such that only a small quantity of it needs to be used with a CO2 laser under ambient operating conditions. This object is achieved by a catalyst that consists essentially of about 1 to 40 percent by weight of one or more platinum group metals (Pt, Pd, Rh, Ir, Ru, Os, Pt being preferred); about 1 to 90 percent by weight of one or more oxides of reducible metals having multiple valence states (such as Sn, Ti, Mn, Cu, and Ce, with SnO2 being preferred); and about 1 to 90 percent by weight of a compound that can bind water to its structure (such as silica gel, calcium chloride, magnesium sulfate, hydrated alumina, and magnesium perchlorate, with silica gel being preferred). Especially beneficial results are obtained when platinum is present in the

  15. Oxygen reduction reaction on palladium-cobalt alloy catalysts for polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Oishi, Kentaro

    The Oxygen Reduction Reaction (ORR) activity in acid medium on Pd-Co was studied in this work. The catalysts were synthesized by two techniques; physical vapor deposition technique and ultrasonic spray reaction technique. The last technique was developed for the first time in our laboratory for the supported electro catalyst preparation and direct deposition onto the carbon paper or gas diffusion electrode the for PEMFC applications. The electrochemical properties such as the amount of hydrogen adsorption/desorption, the oxide formation/reduction of Pd-Co alloy catalyst have not been sufficiently studied before. Therefore these electrochemical properties were investigated by using the Pd-Co thin films prepared by sputtering method. A thin film catalyst cannot be directly used as an electrode of working PEMFCs, however the sputtering method is very useful since the chemical composition of alloy and surface area of the electrode can be controlled easily. Thus the fundamental electrochemical properties such as the amount of hydrogen adsorption/desorption, oxide formation/reduction and oxide reduction peak position on thin films of Pd-Co alloy, Pd and Pt catalysts were determined and their correlations to ORR catalytic activities in acid medium were studied. Enhancements of the catalytic activities for ORR by Pd-Co binary alloys were found to be in agreement with results obtained in previous studies. Ultrasonic spray reaction method was developed for the first time in our laboratory for carbon supported nano-scale catalyst for PEMFC application. Fine catalyst particles supported on high surface area carbon powder are required to apply the catalyst as the PEMFC cathode materials for the commercialization, but none of the studies done before were able to successfully obtain the Pd-Co fine particles which are comparable with the existing carbon supported platinum catalyst (ϕ2-4nm). Therefore the establishment of the catalyst synthesis method for Pd-Co fine particles are

  16. Profiling physicochemical changes within catalyst bodies during preparation: new insights from invasive and noninvasive microspectroscopic studies.

    PubMed

    Espinosa-Alonso, Leticia; Beale, Andrew M; Weckhuysen, Bert M

    2010-09-21

    Cylindrical or spherical catalyst bodies with sizes ranging from tens of micrometers to a few millimeters have a wide variety of industrial applications. They are crucial in the oil refining industry and in the manufacture of bulk and fine chemicals. Their stability, activity, and selectivity are largely dependent on their preparation; thus, achieving the optimum catalyst requires a perfect understanding of the physicochemical processes occurring in a catalyst body during its synthesis. The ultimate goal of the catalyst researcher is to visualize these physicochemical processes as the catalyst is being prepared and without interfering with the system. In order to understand this chemistry and improve catalyst design, researchers need better, less invasive tools to observe this chemistry as it occurs, from the first stages in contact with a precursor all the way through its synthesis. In this Account, we provide an overview of the recent advances in the development of space- and time-resolved spectroscopic methods, from invasive techniques to noninvasive ones, to image the physicochemical processes taking place during the preparation of catalyst bodies. Although several preparation methods are available to produce catalyst bodies, the most common method used in industry is the incipient wetness impregnation. It is the most common method used in industry because it is simple and cost-effective. This method consists of three main steps each of which has an important role in the design of a catalytic material: pore volume impregnation, drying, and thermal treatment. During the impregnation step, the interface between the support surface and the precursor of the active phase at the solid-liquid interface is where the critical synthetic chemistry occurs. Gas-solid and solid-solid interfaces are critical during the drying and thermal treatment steps. Because of the length scale of these catalyst bodies, the interfacial chemistry that occurs during preparation is space

  17. Reduction of Fine Sediment Input: What is Practical and at What Scale?

    NASA Astrophysics Data System (ADS)

    Madej, M.

    2006-12-01

    In the Trinity River basin, northern California, salmon and steelhead populations declined following the construction of dams and diversion of flow. A large-scale restoration program includes goals to augment coarse gravel, reconfigure the floodplain, improve stream temperature regimes, alter stream flows through controlled flow releases, and reduce fine sediment in the mainstem Trinity River. Questions that must be addressed are: what are the current conditions, what is possible to correct, what is practical to correct, and on what scale can restoration be effective? This study assesses restoration effectiveness of one aspect of the program: reduction of fine sediment. To date, techniques used include construction of sediment detention basins and road upgrades or decommissioning. To assess the probable effectiveness of these efforts, the mainstem Trinity River was divided into cells, defined by locations of confluences of large tributaries. In each river cell, fine sediment in mainstem storage was quantified for several sediment mobility categories: active channel bed, gravel bars, floodplain, deltas and riparian berms. Probable fine sediment input from tributaries, primarily from landslides and roads, was compared to the mainstem fine sediment storage volumes and to measured sediment yield from tributaries. For example, in a river cell with 30,000 Mg of fine sediment stored in the active channel bed, the major tributary in that reach delivers about 700 Mg of fine sediment per year. This tributary basin has 160 km of roads with more than 400 stream crossings. The costs to control the fine sediment from this tributary basin may not be justified in terms of making a biologically significant difference in mainstem aquatic habitat quality. In contrast, in other cells, fine sediment input from tributaries is significant when compared with mainstem sediment storage. Transport and storage of fine sediment are dependent on other restoration activities, such as controlled

  18. DESIGN INFORMATION ON FINE PORE AERATION SYSTEMS

    EPA Science Inventory

    Field studies were conducted over several years at municipal wastewater treatment plants employing line pore diffused aeration systems. These studies were designed to produce reliable information on the performance and operational requirements of fine pore devices under process ...

  19. Shock Fabrics in Fine-Grained Micrometeorites

    NASA Astrophysics Data System (ADS)

    Suttle, M. D.; Genge, M. J.; Russell, S. S.

    2016-08-01

    Low grade (S1) shock fabrics are identified in unmelted fine-grained micrometeorites through the presence of aligned dehydration cracks. This study suggests hydrated micrometeorites originate predominantly from rubble-pile asteroids.

  20. Fine needle aspiration of the thyroid

    MedlinePlus

    Thyroid nodule fine needle aspirate biopsy; Biopsy - thyroid - skinny-needle; Skinny-needle thyroid biopsy ... cleaned. A thin needle is inserted into the thyroid, and a sample of thyroid cells and fluid ...

  1. Immobilization of Rocky Flats Graphite Fines Residue

    SciTech Connect

    Rudisill, T.S.

    1999-04-06

    The development of the immobilization process for graphite fines has proceeded through a series of experimental programs. The experimental procedures and results from each series of experiments are discussed in this report.

  2. Catalyst for selective conversion of synthesis gas and method of making the catalyst

    DOEpatents

    Dyer, Paul N.; Pierantozzi, Ronald

    1986-01-01

    A Fischer-Tropsch (F-T) catalyst, a method of making the catalyst and an F-T process utilizing the catalyst by which synthesis gas, particularly carbon-monoxide rich synthesis gas is selectively converted to higher hydrocarbons of relatively narrow carbon number range. In general, the selective and notably stable catalyst, consists of an inert carrier first treated with a Group IV B metal compound (such as zirconium or titanium), preferably an alkoxide compound, and subsequently treated with an organic compound of an F-T metal catalyst, such as cobalt, iron or ruthenium carbonyl. Reactions with air and water and calcination are specifically avoided in the catalyst preparation procedure.

  3. Supported fischer-tropsch catalyst and method of making the catalyst

    DOEpatents

    Dyer, Paul N.; Pierantozzi, Ronald; Withers, Howard P.

    1987-01-01

    A Fischer-Tropsch catalyst and a method of making the catalyst for a Fischer-Tropsch process utilizing the catalyst by which synthesis gas, particularly carbon-monoxide rich synthesis gas, is selectively converted to higher hydrocarbons of relatively narrow carbon number range is disclosed. In general, the selective and notably stable catalyst, consist of an inert carrier first treated with a Group IV B metal compound (such as zirconium or titanium), preferably an alkoxide compound, and subsequently treated with an organic compound of a Fischer-Tropsch metal catalyst, such as cobalt, iron or ruthenium carbonyl. Reactions with air and water and calcination are specifically avoided in the catalyst preparation procedure.

  4. Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid

    MedlinePlus

    ... Index A-Z Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid An ultrasound-guided thyroid biopsy ... Thyroid? What is Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid? During a fine needle aspiration ...

  5. Interaction of fine sediment with alluvial streambeds

    USGS Publications Warehouse

    Jobson, H.E.; Carey, W.P.

    1989-01-01

    An alluvial streambed can have a large capacity to store fine sediments that are extracted from the flow when instream concentrations are high and it can gradually release fine sediment to the flow when the instream concentrations are low. Several types of storage mechanisms are available depending on the relative size distribution of the suspended load and bed material, as well as the flow hydraulics. -from Authors

  6. NUMERICAL MODELING OF FINE SEDIMENT PHYSICAL PROCESSES.

    USGS Publications Warehouse

    Schoellhamer, David H.

    1985-01-01

    Fine sediment in channels, rivers, estuaries, and coastal waters undergo several physical processes including flocculation, floc disruption, deposition, bed consolidation, and resuspension. This paper presents a conceptual model and reviews mathematical models of these physical processes. Several general fine sediment models that simulate some of these processes are reviewed. These general models do not directly simulate flocculation and floc disruption, but the conceptual model and existing functions are shown to adequately model these two processes for one set of laboratory data.

  7. Sulfiding of hydrogel derived catalysts

    SciTech Connect

    Kemp, R.A.

    1991-11-05

    This patent describes a process for hydrotreating hydrocarbon feeds. It comprises contacting the feeds at a temperature in the range of from about 400{degrees} F. to about 850{degrees} F. and a pressure in the range of from about 400 psig to about 2500 psig with a catalyst having improved desulfurization activity prepared by incorporating an element selected from the group consisting of nickel, cobalt and mixtures thereof, and a heavy metal selected from the group consisting of molybdenum, tungsten and mixtures thereof, into an alumina hydrogel containing a phosphorous-containing compound, and sulfiding the catalyst with a gaseous sulfur compound at a temperature of at least about 900{degrees} F. for at least one hour.

  8. Catalyst interaction in a FCCU

    SciTech Connect

    Griffiths, C.; Glendinning, R.

    1986-01-01

    The FCC process is of major importance in modern refineries and the optimum performance of the unit has a marked effect on overall refinery economics. To meet refiners demand for improved selectivity and metals tolerance developments in cracking catalyst technology have accelerated over the last 3 years. In addition, physical properties, such as attrition resistance, particle size distribution and fluidisation characteristics have now to be controlled and optimised in order to maximise unit performance. The fluid cracking catalyst has three main functions in a FCCU: - to supply active acid sites to the reactor, to crack the feedstock; to contain the effect of contaminants, such as nickel and vanadium etc.; to transfer the necessary heat from the regenerator to the reactor system. The catalytic effect in a unit is evident in two ways: - by altering catalytic coke production and by modifying liquid selectivities.

  9. Catalyst for hydrotreating carbonaceous liquids

    DOEpatents

    Berg, Lloyd; McCandless, Frank P.; Ramer, Ronald J.

    1982-01-01

    A catalyst for denitrogenating and desulfurating carbonaceous liquid such as solvent refined coal includes catalytic metal oxides impregnated within a porous base of mostly alumina with relatively large pore diameters, surface area and pore volume. The base material includes pore volumes of 0.7-0.85 ml/g, surface areas of 200-350 m.sup.2 /g and pore diameters of 85-200 Angstroms. The catalytic metals impregnated into these base materials include the oxides of Group VI metals, molybdenum and tungsten, and the oxides of Group VIII metals, nickel and cobalt, in various combinations. These catalysts and bases in combination have effectively promoted the removal of chemically combined sulfur and nitrogen within a continuous flowing mixture of carbonaceous liquid and hydrogen gas.

  10. Recombination Catalysts for Hypersonic Fuels

    NASA Technical Reports Server (NTRS)

    Chinitz, W.

    1998-01-01

    The goal of commercially-viable access to space will require technologies that reduce propulsion system weight and complexity, while extracting maximum energy from the products of combustion. This work is directed toward developing effective nozzle recombination catalysts for the supersonic and hypersonic aeropropulsion engines used to provide such access to space. Effective nozzle recombination will significantly reduce rk=le length (hence, propulsion system weight) and reduce fuel requirements, further decreasing the vehicle's gross lift-off weight. Two such catalysts have been identified in this work, barium and antimony compounds, by developing chemical kinetic reaction mechanisms for these materials and determining the engine performance enhancement for a typical flight trajectory. Significant performance improvements are indicated, using only 2% (mole or mass) of these compounds in the combustor product gas.

  11. Cooperation of catalysts and templates

    NASA Technical Reports Server (NTRS)

    White, D. H.; Kanavarioti, A.; Nibley, C. W.; Macklin, J. W.

    1986-01-01

    In order to understand how self-reproducing molecules could have originated on the primitive Earth or extraterrestrial bodies, it would be useful to find laboratory models of simple molecules which are able to carry out processes of catalysis and templating. Furthermore, it may be anticipated that systems in which several components are acting cooperatively to catalyze each other's synthesis will have different behavior with respect to natural selection than those of purely replicating systems. As the major focus of this work, laboratory models are devised to study the influence of short peptide catalysts on template reactions which produce oligonucleotides or additional peptides. Such catalysts could have been the earliest protoenzymes of selective advantage produced by replicating oligonucleotides. Since this is a complex problem, simpler systems are also studied which embody only one aspect at a time, such as peptide formation with and without a template, peptide catalysis of nontemplated peptide synthesis, and model reactions for replication of the type pioneered by Orgel.

  12. Low Temperature Hydrogenation of Benzene and Cyclohexene: A Comparative Study Between gamma-Al2O3 Supported PtCo and PtNi Bimetallic Catalysts

    SciTech Connect

    Lu, S.; Lonergan, W; Bosco, J; Wang, S; Zhu, Y; Xie, Y; Chen, J

    2008-01-01

    Supported PtCo and PtNi bimetallic and Co, Ni, Pt monometallic catalysts were prepared by impregnation method on ?-Al2O3 and evaluated for the hydrogenation of benzene and cyclohexene at low temperatures (273-343 K) and atmospheric pressure. Results from batch reactor studies with Fourier transform infrared spectroscopy (FTIR) and flow reactor studies both showed that PtCo bimetallic catalysts exhibited significantly higher activity than PtNi and monometallic Co, Ni, and Pt catalysts for benzene hydrogenation, while PtNi catalysts showed higher activity for cyclohexene hydrogenation. Results from H2 chemisorption and H2-temperature-programmed reduction (H2-TPR) studies showed that a small amount of Pt addition could increase the chemisorption capacity and make the reduction of Co or Ni much easier, especially for Co-based catalysts. Extended X-ray absorption fine structure (EXAFS) results confirmed the formation of Pt-Co and Pt-Ni bimetallic bonds in the PtCo and PtNi bimetallic catalysts, supporting the argument from previous surface science and theoretical predictions that these two bimetallic catalysts would have higher hydrogenation activity than the corresponding monometallic catalysts.

  13. Crossing the divide between homogeneous and heterogeneous catalysis in water oxidation.

    PubMed

    Vannucci, Aaron K; Alibabaei, Leila; Losego, Mark D; Concepcion, Javier J; Kalanyan, Berç; Parsons, Gregory N; Meyer, Thomas J

    2013-12-24

    Enhancing the surface binding stability of chromophores, catalysts, and chromophore-catalyst assemblies attached to metal oxide surfaces is an important element in furthering the development of dye sensitized solar cells, photoelectrosynthesis cells, and interfacial molecular catalysis. Phosphonate-derivatized catalysts and molecular assemblies provide a basis for sustained water oxidation on these surfaces in acidic solution but are unstable toward hydrolysis and loss from surfaces as the pH is increased. Here, we report enhanced surface binding stability of a phosphonate-derivatized water oxidation catalyst over a wide pH range (1-12) by atomic layer deposition of an overlayer of TiO2. Increased stability of surface binding, and the reactivity of the bound catalyst, provides a hybrid approach to heterogeneous catalysis combining the advantages of systematic modifications possible by chemical synthesis with heterogeneous reactivity. For the surface-stabilized catalyst, greatly enhanced rates of water oxidation are observed upon addition of buffer bases -H2PO(-)(4)/HPO(2-)(4), B(OH)3/B(OH)2 O-, HPO(2-)4 /PO(3-)(4) - and with a pathway identified in which O-atom transfer to OH(-) occurs with a rate constant increase of 10(6) compared to water oxidation in acid. PMID:24277824

  14. Crossing the divide between homogeneous and heterogeneous catalysis in water oxidation.

    PubMed

    Vannucci, Aaron K; Alibabaei, Leila; Losego, Mark D; Concepcion, Javier J; Kalanyan, Berç; Parsons, Gregory N; Meyer, Thomas J

    2013-12-24

    Enhancing the surface binding stability of chromophores, catalysts, and chromophore-catalyst assemblies attached to metal oxide surfaces is an important element in furthering the development of dye sensitized solar cells, photoelectrosynthesis cells, and interfacial molecular catalysis. Phosphonate-derivatized catalysts and molecular assemblies provide a basis for sustained water oxidation on these surfaces in acidic solution but are unstable toward hydrolysis and loss from surfaces as the pH is increased. Here, we report enhanced surface binding stability of a phosphonate-derivatized water oxidation catalyst over a wide pH range (1-12) by atomic layer deposition of an overlayer of TiO2. Increased stability of surface binding, and the reactivity of the bound catalyst, provides a hybrid approach to heterogeneous catalysis combining the advantages of systematic modifications possible by chemical synthesis with heterogeneous reactivity. For the surface-stabilized catalyst, greatly enhanced rates of water oxidation are observed upon addition of buffer bases -H2PO(-)(4)/HPO(2-)(4), B(OH)3/B(OH)2 O-, HPO(2-)4 /PO(3-)(4) - and with a pathway identified in which O-atom transfer to OH(-) occurs with a rate constant increase of 10(6) compared to water oxidation in acid.

  15. Crossing the divide between homogeneous and heterogeneous catalysis in water oxidation

    PubMed Central

    Vannucci, Aaron K.; Alibabaei, Leila; Losego, Mark D.; Concepcion, Javier J.; Kalanyan, Berç; Parsons, Gregory N.; Meyer, Thomas J.

    2013-01-01

    Enhancing the surface binding stability of chromophores, catalysts, and chromophore–catalyst assemblies attached to metal oxide surfaces is an important element in furthering the development of dye sensitized solar cells, photoelectrosynthesis cells, and interfacial molecular catalysis. Phosphonate-derivatized catalysts and molecular assemblies provide a basis for sustained water oxidation on these surfaces in acidic solution but are unstable toward hydrolysis and loss from surfaces as the pH is increased. Here, we report enhanced surface binding stability of a phosphonate-derivatized water oxidation catalyst over a wide pH range (1–12) by atomic layer deposition of an overlayer of TiO2. Increased stability of surface binding, and the reactivity of the bound catalyst, provides a hybrid approach to heterogeneous catalysis combining the advantages of systematic modifications possible by chemical synthesis with heterogeneous reactivity. For the surface-stabilized catalyst, greatly enhanced rates of water oxidation are observed upon addition of buffer bases and with a pathway identified in which O-atom transfer to OH− occurs with a rate constant increase of 106 compared to water oxidation in acid. PMID:24277824

  16. Catalyst Development for Hydrogen Peroxide Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morlan, P. W.; Wu, P.-K.; Ruttle, D. W.; Fuller, R. P.; Nejad, A. S.; Anderson, W. E.

    1999-01-01

    The development of various catalysts of hydrogen peroxide was conducted for the applications of liquid rocket engines. The catalyst development includes silver screen technology, solid catalyst technology, and homogeneous catalyst technology. The silver screen technology development was performed with 85% (by weight) hydrogen peroxide. The results of this investigation were used as the basis for the catalyst design of a pressure-fed liquid-fueled upper stage engine. Both silver-plated nickel 200 screens and pure silver screens were used as the active metal catalyst during the investigation, The data indicate that a high decomposition efficiency (greater than 90%) of 85% hydrogen peroxide can be achieved at a bed loading of 0.5 lbm/sq in/sec with both pure silver and silver plated screens. Samarium oxide coating, however, was found to retard the decomposition process and the catalyst bed was flooded at lower bed loading. A throughput of 200 lbm of hydrogen peroxide (1000 second run time) was tested to evaluate the catalyst aging issue and performance degradation was observed starting at approximately 400 seconds. Catalyst beds of 3.5 inch in diameter was fabricated using the same configuration for a 1,000-lbf rocket engine. High decomposition efficiency was obtained with a low pressure drop across the bed. Solid catalyst using precious metal was also developed for the decomposition of hydrogen peroxide from 85% to 98% by weight. Preliminary results show that the catalyst has a strong reactivity even after 15 minutes of peroxide decomposition. The development effort also includes the homogeneous catalyst technology. Various non-toxic catalysts were evaluated with 98% peroxide and hydrocarbon fuels. The results of open cup drop tests indicate an ignition delay around 11 ms.

  17. Pelletization of fine coals. Final report

    SciTech Connect

    Sastry, K.V.S.

    1995-12-31

    Coal is one of the most abundant energy resources in the US with nearly 800 million tons of it being mined annually. Process and environmental demands for low-ash, low-sulfur coals and economic constraints for high productivity are leading the coal industry to use such modern mining methods as longwall mining and such newer coal processing techniques as froth flotation, oil agglomeration, chemical cleaning and synthetic fuel production. All these processes are faced with one common problem area--fine coals. Dealing effectively with these fine coals during handling, storage, transportation, and/or processing continues to be a challenge facing the industry. Agglomeration by the unit operation of pelletization consists of tumbling moist fines in drums or discs. Past experimental work and limited commercial practice have shown that pelletization can alleviate the problems associated with fine coals. However, it was recognized that there exists a serious need for delineating the fundamental principles of fine coal pelletization. Accordingly, a research program has been carried involving four specific topics: (i) experimental investigation of coal pelletization kinetics, (ii) understanding the surface principles of coal pelletization, (iii) modeling of coal pelletization processes, and (iv) simulation of fine coal pelletization circuits. This report summarizes the major findings and provides relevant details of the research effort.

  18. Hydrogen activation by magnesia catalysts

    SciTech Connect

    Yulin Gu; Brenner, A. )

    1992-07-01

    Hydrogen activation by magnesia catalysts was investigated by studying H{sub 2}-D{sub 2} exchange. The number of active sites, surface composition, rate, and mechanism of the reaction were investigated as a function of the activation temperature. Behavior of a commercial magnesia and a catalyst synthesized from Mg(OH){sub 2} were similar, although the latter catalyst had a much larger surface area. The upper limit for the number of active sites was determined in the classical manner by using selective poisoning by CO. A novel technique involving monitoring the stoichiometric reaction between magnesia and D{sub 2}(g) enabled the very unusual determination of the lower limit for the number of active sites. Thus, the true number of active sites is bracketed within the upper and lower limits. Maximal activity occurred after activation at 700 C. The number of active sites is about 10{sup 12}/cm{sup 2}, which is 10{sup 3}-fold higher than formerly reported on the basis of EPR data. The turnover frequency at 273 K and a partial pressure of 20 Torr of an equimolar mixture of H{sub 2}-D{sub 2} is 4 s{sup {minus}1}, roughly 10{sup 3}-fold less than previously reported. The site density and activity are now consistent with expected values, rather than the anomalous values previously reported. The hydroxyl coverage of the surface was determined in a novel manner using thermogravimetric analysis over the temperature range of 300 to 1,400 K. The catalysts are of low activity when the surface is either of very high or very low hydroxyl content. A mechanism in which the active site includes an ensemble consisting of a Mg{sup 2+} center and neighboring surface OH and O{sup 2{minus}} is proposed.

  19. Supercritical/Solid Catalyst (SSC)

    ScienceCinema

    None

    2016-07-12

    INL's patented, continuous-flow Supercritical/Solid Catalyst (SSC) produces the highest ASTM-quality B-100 biodiesel from waste fats, oils, and greases at the site of waste generation. SSC delivers low-cost transportation fuel, avoids significant landfill costs for municipalities, and reduces potent methane and other emissions produced in landfills from these wastes. You can learn more about INL's energy research programs at http://www.facebook.com/idahonationallaboratory.

  20. Catalyst for Expanding Human Spaceflight

    NASA Technical Reports Server (NTRS)

    Lueders, Kathryn L.

    2014-01-01

    History supplies us with many models of how and how not to commercialize an industry. This presentation draws parallels between industries with government roots, like the railroad, air transport, communications and the internet, and NASAs Commercial Crew Program. In these examples, government served as a catalyst for what became a booming industry. The building block approach the Commercial Crew Program is taking is very simple -- establish a need, laying the groundwork, enabling industry and legal framework.