WorldWideScience

Sample records for alloy catalysts aided

  1. Alloy catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use...

  2. Platinum-ruthenium-palladium alloys for use as a fuel cell catalyst

    Science.gov (United States)

    Gorer, Alexander

    2002-01-01

    A noble metal alloy composition for a fuel cell catalyst, a ternary alloy composition containing platinum, ruthenium and palladium. The alloy shows increased activity as compared to well-known catalysts.

  3. Computer-Aided Design of Solid Catalysts

    Czech Academy of Sciences Publication Activity Database

    Holeňa, Martin; Baerns, M.

    Weinheim: Wiley, 2008 - (Ertl, G.; Knözinger, H.; Schüth, F.; Weitkamp, J.), s. 66-81 ISBN 978-3-527-31241-2 Institutional research plan: CEZ:AV0Z10300504 Keywords : combinatorial catalysis * design of experiments * catalyst optimization, * evolutionary methods * data analysis * artificial neural networks Subject RIV: IN - Informatics, Computer Science

  4. Electrodeposited NiCu Alloy Catalysts for Glucose Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jieun; Park, Hansoo; Kim, Sookil [Chung-Ang Univ., Seoul (Korea, Republic of); Ahn, Sang Hyun; Jang, Jong Hyun [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2014-07-15

    NiCu alloys have been suggested as potential candidates for catalysts in glucose oxidation. In this study, NiCu alloys with different compositions were prepared on a glassy carbon substrate by changing the electrodeposition potential to examine the effect of Ni/Cu ratios in alloys on catalytic activity toward glucose oxidation. Cyclic voltammetry and chronoamperometry showed that NiCu alloys had higher catalytic activity than pure Ni and Cu catalysts. Especially, Ni{sub 59}Cu{sub 41} had superior catalytic activity, which was about twice that of Ni at a given oxidation potential. X-ray analyses showed that the oxidation state of Ni in NiCu alloys was increased with the content of Cu by lattice expansion. Ni components in alloys with higher oxidation state were more effective in the oxidation of glucose.

  5. Electrodeposited NiCu Alloy Catalysts for Glucose Oxidation

    International Nuclear Information System (INIS)

    NiCu alloys have been suggested as potential candidates for catalysts in glucose oxidation. In this study, NiCu alloys with different compositions were prepared on a glassy carbon substrate by changing the electrodeposition potential to examine the effect of Ni/Cu ratios in alloys on catalytic activity toward glucose oxidation. Cyclic voltammetry and chronoamperometry showed that NiCu alloys had higher catalytic activity than pure Ni and Cu catalysts. Especially, Ni59Cu41 had superior catalytic activity, which was about twice that of Ni at a given oxidation potential. X-ray analyses showed that the oxidation state of Ni in NiCu alloys was increased with the content of Cu by lattice expansion. Ni components in alloys with higher oxidation state were more effective in the oxidation of glucose

  6. Design of a surface alloy catalyst for steam reforming

    DEFF Research Database (Denmark)

    Besenbacher, F.; Chorkendorff, Ib; Clausen, B.S.;

    1998-01-01

    Detailed studies of elementary chemical processes on well-characterized single crystal surfaces have contributed substantially to the understanding of heterogeneous catalysis. insight into the structure of surface alloys combined with an understanding of the relation between the surface composition...... and reactivity is shown to lead directly to new ideas for catalyst design, The feasibility of such an approach is illustrated by the synthesis, characterization, and tests of a high-surface area gold-nickel catalyst for steam reforming....

  7. Genetic Algorithm Procreation Operators for Alloy Nanoparticle Catalysts

    DEFF Research Database (Denmark)

    Lysgaard, Steen; Landis, David Dominic; Bligaard, Thomas;

    2014-01-01

    The long-term stability of binary nanoparticles and clusters is one of the main challenges in the development of novel (electro-)catalysts for e.g. CO2 reduction. Here, we present a method for predicting the optimal composition and structure of alloy nanoparticles and clusters, with particular...

  8. Furfural Hydrogenation on Alloyed Copper Catalysts With Additives of Ferrosilicium

    Directory of Open Access Journals (Sweden)

    T. K. Akilov

    2015-12-01

    Full Text Available The present work is dedicated to the study of influence of ferrosilicium additives [FA*-ferroalloy containing (% mass: 46.8 Si, ~53,0 Fe, other are (C, P, S impurities] on the activity of alloyed Gu-Al = 50-50 catalyst in the reaction of furfural hydrogenation under hydrogen pressure. Components content varied (% mass: Cu- 40...49, aluminum- 50, FA* -1.0...10.0. The catalysts were prepared from 1g alloys by leaching it with 20% of aqueous solution of caustic soda in boiling water-bath during 1 hour. The phase composition and structure of alloys were investigated by means of roentgenographic and X-ray spectrum methods.

  9. Highly Dispersed Alloy Catalyst for Durability

    Energy Technology Data Exchange (ETDEWEB)

    Murthi, Vivek S.; Izzo, Elise; Bi, Wu; Guerrero, Sandra; Protsailo, Lesia

    2013-01-08

    Achieving DOE's stated 5000-hr durability goal for light-duty vehicles by 2015 will require MEAs with characteristics that are beyond the current state of the art. Significant effort was placed on developing advanced durable cathode catalysts to arrive at the best possible electrode for high performance and durability, as well as developing manufacturing processes that yield significant cost benefit. Accordingly, the overall goal of this project was to develop and construct advanced MEAs that will improve performance and durability while reducing the cost of PEMFC stacks. The project, led by UTC Power, focused on developing new catalysts/supports and integrating them with existing materials (membranes and gas diffusion layers (GDLs)) using state-of-the-art fabrication methods capable of meeting the durability requirements essential for automotive applications. Specifically, the project work aimed to lower platinum group metals (PGM) loading while increasing performance and durability. Appropriate catalysts and MEA configuration were down-selected that protects the membrane, and the layers were tailored to optimize the movements of reactants and product water through the cell to maximize performance while maintaining durability.

  10. Advances in chemical synthesis and application of metal-metalloid amorphous alloy nanoparticulate catalysts

    Institute of Scientific and Technical Information of China (English)

    WU Zhijie; LI Wei; ZHANG Minghui; TAO Keyi

    2007-01-01

    This paper reviews the advances in the chemical synthesis and application of metal-metalloid amorphous alloy nanoparticles consisting of transition metal (M) and metalloid elements (B,P).After a brief introduction on the history of amorphous alloy catalysts,the paper focuses on the properties and characterization of amorphous alloy catalysts,and recent developments in the solution-phase synthesis of amorphous alloy nanoparticles.This paper further outlines the applications of amorphous alloys,with special emphasis on the problems and strategies for the application of amorphous alloy nanoparticles in catalytic reactions.

  11. Novel Carbon Nanotubes-supported NiB Amorphors Alloy Catalyst for Benzene Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Mei Hua YANG; Rong Bin ZHANG; Feng Yi LI

    2004-01-01

    The NiB amorphous alloy catalysts supported on CNTs and alumina were prepared by impregnation and chemical reduction. The gas-phase benzene hydrogenation was used as a probe reaction to evaluate the catalytic activity. The result showed that the NiB amorphous alloy catalyst supported on carbon nanotubes exhibited higher activity than that supported on alumina.

  12. Pd-Au/C catalysts with different alloying degrees for ethanol oxidation in alkaline media

    International Nuclear Information System (INIS)

    High alloyed Pd-Au/C catalyst is prepared through a rate-limiting strategy in water/ethylene glycol solution. Pd/C and low alloyed Pd-Au/C catalysts are prepared with trisodium citrate and sodium borohydride as stabilizing and reducing agents, respectively. Transmission electron microscopy (TEM) shows that the synthesized Pd(Au) particles are well dispersed on the catalysts. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) show that the high alloyed Pd-Au/C catalyst presents a relatively homogenous structure while the low alloyed Pd-Au/C catalyst presents a Pd-rich shell/Au-rich core structure. Electrochemical characterization shows that the low alloyed Pd-Au/C catalyst exhibits the best catalytic activity for ethanol oxidation reaction (EOR) in alkaline media, which could be attributed to its relatively large exposed Pd surface area as compared with the high alloyed Pd-Au/C catalyst due to its Pd-rich shell structure and its enhanced adsorption of OHads as compared with Pd/C catalyst due to its core-shell structure

  13. Tackling CO Poisoning with Single-Atom Alloy Catalysts.

    Science.gov (United States)

    Liu, Jilei; Lucci, Felicia R; Yang, Ming; Lee, Sungsik; Marcinkowski, Matthew D; Therrien, Andrew J; Williams, Christopher T; Sykes, E Charles H; Flytzani-Stephanopoulos, Maria

    2016-05-25

    Platinum catalysts are extensively used in the chemical industry and as electrocatalysts in fuel cells. Pt is notorious for its sensitivity to poisoning by strong CO adsorption. Here we demonstrate that the single-atom alloy (SAA) strategy applied to Pt reduces the binding strength of CO while maintaining catalytic performance. By using surface sensitive studies, we determined the binding strength of CO to different Pt ensembles, and this in turn guided the preparation of PtCu alloy nanoparticles (NPs). The atomic ratio Pt:Cu = 1:125 yielded a SAA which exhibited excellent CO tolerance in H2 activation, the key elementary step for hydrogenation and hydrogen electro-oxidation. As a probe reaction, the selective hydrogenation of acetylene to ethene was performed under flow conditions on the SAA NPs supported on alumina without activity loss in the presence of CO. The ability to maintain reactivity in the presence of CO is vital to other industrial reaction systems, such as hydrocarbon oxidation, electrochemical methanol oxidation, and hydrogen fuel cells. PMID:27167705

  14. Computational thermodynamics aided design of novel ferritic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Tianyi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tan, Lizhen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-06-30

    With the aid of computational thermodynamics, Ni was identified to suppress the liquidus temperature of Fe2Zr and four Fe-Cr-Ni-Zr alloys were designed to study the Ni effect on the phase stability of Fe2Zr laves_phase. These alloys were fabricated through traditional arc-metling, followed by annealing at 1000 C for 336 hours and 700 C for 1275 hours. The microstructure were examined and characterized by SEM BSE image, EDS compositional mapping and point scan, XRD and TEM analysis. The major results were summarized below: 1)For investigated alloys with 12wt% Cr, 3~6wt% Zr and 3~9 wt%Ni, the phases in equilibrium with the BCC phase are C15_Laves phase, Fe23Zr6 phase. The volume fraction of intermetallic phases increases with Ni and Zr contents. 2)Instead of (Fe,Cr)2Zr C14_Laves phase, Ni stabilizes the C15_Laves structure in Fe-Cr-Ni-Zr alloys by substituting Fe and Cr atoms with Ni atoms in the first sublattice. 3)Fe23Zr6, that is metastable in the Fe-Cr-Zr ternary, is also stabilized by Ni addition. 4)Ni7Zr2 phase was observed in samples with high Ni/Zr ratio. Extensive solubility of Fe was identified in the phase. The microstructural and composition results obtained from this study will be incorportated into the the Fe-Cr-Ni-Zr database. The current samples will be subjected to ion irradiaition to be compared with those results for Fe-Cr-Zr alloys. Additional alloys will be designed to form (Fe,Cr,Ni)2Zr nanoprecipitates for further studies.

  15. Ni-Mo-W catalysts synthesized by mechanical alloying for HDS of dibenzothiophene

    International Nuclear Information System (INIS)

    In this work we reported new trimetallic Ni-Mo-W catalysts synthesized by leaching an Ni-Mo-W-Al alloy produced by mechanical alloying. The materials were tested in the hydrodesulphurization of dibenzothiophene and characterized by scanning electron microscopy, trasmission electron microscopy, X-ray diffraction and specific surface area measurements by using the BET method. This kind of catalysts shows a moderate catalytic activity, due to the synergized effect of small particle and crystal size, and presence of porosity

  16. Mechanisms of oxygen reduction reactions for carbon alloy catalysts via first principles molecular dynamics

    International Nuclear Information System (INIS)

    Carbon alloy catalysts (CACs) are one of promising candidates for platinum-substitute cathode catalysts for polymer electrolyte fuel cells. We have investigated possible mechanisms of oxygen reduction reactions (ORRs) for CACs via first-principles-based molecular dynamics simulations. In this contribution, we review possible ORRs at likely catalytic sites of CACs suggested from our simulations. (author)

  17. Metalloporphyrin catalysts for oxygen reduction developed using computer-aided molecular design

    Energy Technology Data Exchange (ETDEWEB)

    Ryba, G.N.; Hobbs, J.D.; Shelnutt, J.A. [and others

    1996-04-01

    The objective of this project is the development of a new class of metalloporphyrin materials used as catalsyts for use in fuel cell applications. The metalloporphyrins are excellent candidates for use as catalysts at both the anode and cathode. The catalysts reduce oxygen in 1 M potassium hydroxide, as well as in 2 M sulfuric acid. Covalent attachment to carbon supports is being investigated. The computer-aided molecular design is an iterative process, in which experimental results feed back into the design of future catalysts.

  18. Miniature fuel cell with monolithically fabricated Si electrodes - Alloy catalyst formation -

    Science.gov (United States)

    Ogura, Daiki; Suzuki, Takahiro; Katayama, Noboru; Dowaki, Kiyoshi; Hayase, Masanori

    2013-12-01

    A novel Pd-Pt catalyst formation process was proposed for reduction of Pt usage. In our miniature fuel cells, porous Pt was used as the catalyst, and the Pt usage was quite high. To reduce the Pt usage, we have attempted to deposit Pt on porous Pd by galvanic replacement, and relatively large output was demonstrated. In this study, in order to reduce more Pt usage and explore the alloy catalyst formation process, atomic layer deposition by UPD-SLRR (Under Potential Deposition - Surface Limited Redox Replacement) was applied to the Pd-Pt catalyst formation. The new process was verified at each process steps by EDS elemental analysis, and the expected spectra were obtained. Prototype cells were constructed by the new process, and cell output was raised to 420mW/cm2 by the Pd-Pt catalyst from 125mW/cm2 with Pd catalyst.

  19. Miniature fuel cell with monolithically fabricated Si electrodes – Alloy catalyst formation –

    International Nuclear Information System (INIS)

    A novel Pd-Pt catalyst formation process was proposed for reduction of Pt usage. In our miniature fuel cells, porous Pt was used as the catalyst, and the Pt usage was quite high. To reduce the Pt usage, we have attempted to deposit Pt on porous Pd by galvanic replacement, and relatively large output was demonstrated. In this study, in order to reduce more Pt usage and explore the alloy catalyst formation process, atomic layer deposition by UPD-SLRR (Under Potential Deposition – Surface Limited Redox Replacement) was applied to the Pd-Pt catalyst formation. The new process was verified at each process steps by EDS elemental analysis, and the expected spectra were obtained. Prototype cells were constructed by the new process, and cell output was raised to 420mW/cm2 by the Pd-Pt catalyst from 125mW/cm2 with Pd catalyst

  20. Structure, activity, and stability of platinum alloys as catalysts for the oxygen reduction reaction

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg

    essential for wide-spread use of this technology. platinum alloys have shown great promise as more active catalysts, which are still stable under reaction conditions. We have investigated these systems on multiple scales, using either Density Functional Theory (DFT) or Effective Medium Theory (EMT......In this thesis I present our work on theoretical modelling of platinum alloys as catalysts for the Oxygen Reduction Reaction (ORR). The losses associated with the kinetics of the ORR is the main bottleneck in low-temperature fuel cells for transport applications, and more active catalysts are...... increased activity that has been seen experimentally. We show how the platinum-platinum distance at the surface is decreased for a variety of alloy phases in the core, with greater compression of the overlayer for core phases with lattice parameters which are either much smaller or much larger than pure...

  1. SURFACE STRUCTURE AND COMPOSITION CHANGES ON PLATINUM - RHODIUM ALLOY CATALYSTS

    OpenAIRE

    McCabe, A.; Smith, G.

    1984-01-01

    Platinum-rhodium gauze catalysts used in the manufacture of nitric acid undergo an extensive surface reconstruction process. This has been investigated using a miniature catalytic reactor, FIM atom probe, electron microscopy and X-ray techniques. A mechanism involving vapour transport is proposed to explain the main features of the variation in catalyst behaviour with operating conditions.

  2. Ethanol electro-oxidation on partially alloyed Pt-Sn-Rh/C catalysts

    International Nuclear Information System (INIS)

    Ternary Pt-Sn-Rh/C catalysts of Pt:Sn:Rh = 1:0.8:0.2 and 1:1:0.33 atomic ratios were synthesized using the formic acid method and their electrochemical activities were compared for ethanol oxidation with that of binary Pt-Sn/C (1:1) and Pt-Rh/C (1:0.11) catalysts. XRD analysis indicated the presence of Sn in both alloyed and oxide form and suggested the formation of a ternary Pt-Sn-Rh alloy in both catalysts. The particle size by TEM was around 3.5 nm for all catalysts. The efficiency for Pt utilization increased with Rh content. Pt-Sn-Rh/C catalysts exhibited higher catalytic activity for ethanol oxidation than Pt-Rh/C, but lower than Pt-Sn/C. Among ternary catalysts, Pt-Sn-Rh/C (1:0.8:0.2) was the most active. In situ IRRAS showed Rh plays a dual counteracting role during ethanol electro-oxidation on Pt-Sn-Rh/C catalysts, once it promotes C-C bond breaking, thus favouring CO2 formation, but hinders adsorption of ethanol, decreasing the production of acetic acid

  3. Skeletal Amorphous Nickel Based Alloy Catalysts and Magnetically Stabilized Bed Hydrogenation Technology

    Institute of Scientific and Technical Information of China (English)

    Min Enze

    2004-01-01

    Looking toward 21 century, smaller, cleaner and more energy-efficient technology will be an important trend in the development of chemical industry. In light of the new process requirements,a number of technology breakthroughs have occurred. One of these discoveries, the magnetically stabilized bed (MSB), has been proven a powerful process for intensification. Since its initial research in the late 1980's at Research Institute of Petroleum Processing (RIPP), the MSB technology and related catalytic material have matured rapidly through an intensive research and engineering program, primarily focused on its scaling-up.In this paper, we report the discovery of a novel skeletal amorphous nickel-based alloy and its use in magnetically stabilized bed (MSB). Amorphous alloys are new kinds of catalytic materials with short-range order but long-range disorder structure. In comparison with Raney Ni, the skeletal amorphous nickel-based alloy has an increasingly higher activity in the hydrogenation of reactive groups and compounds including nitro, nitrile, olefin, acetylene, aromatics, etc. Up to now, the amorphous nickel based alloy catalysts, SRNA series catalyst, one with high Ni ratio have been commercially manufactured more than four year. The new SRNA catalyst has been successfully implemented for hydrogenation applications in slurry reactor at Balin Petrochemical, SINOPEC.SRNA catalyst with further improvement in catalytic activity and stability raise its relative stability to 2~4 times of that of conventional catalyst. In the course of the long-cycle operation of SRNA-4 the excellent catalyst activity and stability can bring about such advantage as low reaction temperature, good selectivity and low catalyst resumption.Magnetically stabilized bed (MSB), a fluidized bed of magnetizable particles by applying a spatially uniform and time-invariant magnetic field oriented axially relative to the fluidizing fluid flow, had many advantages such as the low pressure drop and

  4. Pt Monolayer Shell on Nitrided Alloy Core—A Path to Highly Stable Oxygen Reduction Catalyst

    Directory of Open Access Journals (Sweden)

    Jue Hu

    2015-07-01

    Full Text Available The inadequate activity and stability of Pt as a cathode catalyst under the severe operation conditions are the critical problems facing the application of the proton exchange membrane fuel cell (PEMFC. Here we report on a novel route to synthesize highly active and stable oxygen reduction catalysts by depositing Pt monolayer on a nitrided alloy core. The prepared PtMLPdNiN/C catalyst retains 89% of the initial electrochemical surface area after 50,000 cycles between potentials 0.6 and 1.0 V. By correlating electron energy-loss spectroscopy and X-ray absorption spectroscopy analyses with electrochemical measurements, we found that the significant improvement of stability of the PtMLPdNiN/C catalyst is caused by nitrogen doping while reducing the total precious metal loading.

  5. Palladium and Tin Alloyed Catalysts for the Ethanol Oxidation Reaction in an Alkaline Medium

    Energy Technology Data Exchange (ETDEWEB)

    Su D.; Du W.; Mackenzie K.E.; Milano D.F.; Deskins N.A.; Teng X.

    2012-02-01

    In this paper, we present a study of a series of carbon-supported Pd-Sn binary alloyed catalysts prepared through a modified Polyol method as anode electrocatalysts for direct ethanol fuel cell reactions in an alkaline medium. Transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and aberration-corrected scanning transmission electron microscopy equipped with electron energy loss spectroscopy were used to characterize the Pd-Sn/C catalysts, where homogeneous Pd-Sn alloys were determined to be present with the surface Sn being partially oxidized. Among various Pd-Sn catalysts, Pd{sub 86}Sn{sub 14}/C catalysts showed much enhanced current densities in cyclic voltammetric and chronoamperometric measurements, compared to commercial Pd/C (Johnson Matthey). The overall rate law of ethanol oxidation reaction for both Pd{sub 86}Sn{sub 14}/C and commercial Pd/C were also determined, which clearly showed that Pd{sub 86}Sn{sub 14}/C was more favorable in high ethanol concentration and/or high pH environment. Density functional theory calculations also confirmed Pd-Sn alloy structures would result in lower reaction energies for the dehydrogenation of ethanol, compared to the pure Pd crystal.

  6. Low-temperature, vapor-liquid-solid, laterally grown silicon films using alloyed catalysts

    Science.gov (United States)

    LeBoeuf, Jerome L.; Brodusch, Nicolas; Gauvin, Raynald; Quitoriano, Nathaniel J.

    2014-12-01

    Using amorphous oxide templates known as micro-crucibles which confine a vapor-liquid-solid catalyst to a specific geometry, two-dimensional silicon thin-films of a single orientation have been grown laterally over an amorphous substrate and defects within crystals have been necked out. The vapor-liquid-solid catalysts consisted nominally of 99% gold with 1% titanium, chromium, or aluminum, and each alloy affected the processing of micro-crucibles and growth within them significantly. It was found that chromium additions inhibited the catalytic effect of the gold catalysts, titanium changed the morphology of the catalyst during processing and aluminum stabilized a potential third phase in the gold-silicon system upon cooling. Two mechanisms for growing undesired nanowires were identified both of which hindered the VLS film growth, fast silane cracking rates and poor gold etching, which left gold nanoparticles near the gold-vapor interface. To reduce the silane cracking rates, growth was done at a lower temperature while an engineered heat and deposition profile helped to reduce NWs caused by the second mechanism. Through experimenting with catalyst compositions, the fundamental mechanisms which produce concentration gradients across the gold-silicon alloy within a given micro-crucible have been proposed. Using the postulated mechanisms, micro-crucibles were designed which promote high-quality, single crystal growth of semiconductors.

  7. Nickel Alloy Catalysts for the Anode of a High Temperature PEM Direct Propane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Shadi Vafaeyan

    2014-01-01

    Full Text Available High temperature polymer electrode membrane fuel cells that use hydrocarbon as the fuel have many theoretical advantages over those that use hydrogen. For example, nonprecious metal catalysts can replace platinum. In this work, two of the four propane fuel cell reactions, propane dehydrogenation and water dissociation, were examined using nickel alloy catalysts. The adsorption energies of both propane and water decreased as the Fe content of Ni/Fe alloys increased. In contrast, they both increased as the Cu content of Ni/Cu alloys increased. The activation energy for the dehydrogenation of propane (a nonpolar molecule changed very little, even though the adsorption energy changed substantially as a function of alloy composition. In contrast, the activation energy for dissociation of water (a molecule that can be polarized decreased markedly as the energy of adsorption decreased. The different relationship between activation energy and adsorption energy for propane dehydrogenation and water dissociation alloys was attributed to propane being a nonpolar molecule and water being a molecule that can be polarized.

  8. Alloyed Ni-Fe nanoparticles as catalysts for NH3 decomposition

    DEFF Research Database (Denmark)

    Simonsen, Søren Bredmose; Chakraborty, Debasish; Chorkendorff, Ib;

    2012-01-01

    A rational design approach was used to develop an alloyed Ni-Fe/Al2O3 catalyst for decomposition of ammonia. The dependence of the catalytic activity is tested as a function of the Ni-to-Fe ratio, the type of Ni-Fe alloy phase, the metal loading and the type of oxide support. In the tests with hi...... smallest particles in terms of catalytic activity per active site. Compared with SiO2, ZrO2 and TiO2, the support materials Al2O3 or Mg-Al-spinel give the highest performance in the high temperature range....

  9. Oxide-supported PtCo alloy catalyst for intermediate temperature polymer electrolyte fuel cells

    OpenAIRE

    Stassi, Alessandro; Gatto, Irene; Baglio, Vincenzo; Passalacqua, Enza; Aricò, Antonino S.

    2013-01-01

    International audience A Pt-Co alloy catalyst supported on a Ta-doped Ti-oxide was investigated for the oxygen reduction reaction in a polymer electrolyte fuel cell (PEMFC) operating between 80° and 110 °C at different relative humidity (100% and 33% R.H.). A crystalline Anatase phase was obtained for the Ta-doped Ti-oxide support with BET surface area of about 150 m2/g. Pt and Pt3Co1 nanoparticles dispersed on the Ta-doped Ti-oxide showed a crystallite size of 3.9 and 2.9 nm, respectively...

  10. Magnetically stabilized bed reactor for selective hydrogenation of olefins in reformate with amorphous nickel alloy catalyst

    Institute of Scientific and Technical Information of China (English)

    Xuhong; Mu; Enze; Min

    2007-01-01

    A magnetically stabilized bed (MSB) reactor for selective hydrogenation of olefins in reformate was developed by combining the advantages of MSB and amorphous nickel alloy catalyst. The effects of operating conditions, such as temperature, pressure, liquid space velocity, hydrogen-to-oil ratio, and magnetic field intensity on the reaction were studied. A mathematical model of MSB reactor for hydrogenation of olefins in reformate was established. A reforming flow scheme with a post-hydrogenation MSB reactor was proposed. Finally, MSB hydrogenation was compared with clay treatment and conventional post-hydrogenation.

  11. First-principles density functional calculations for Mg alloys: A tool to aid in alloy development

    International Nuclear Information System (INIS)

    In studying the thermodynamics and phase stability of Mg alloys, one is often confronted with the lack of accurate, quantitative experimental data. This deficiency can be partially rectified via first-principles calculations based on density functional theory. In this paper, we will illustrate the utility of first-principles energetics for Mg alloys using three case studies (i) formation energies of ordered/disordered solid phases; (ii) solute-vacancy binding energies in Mg; (iii) point defect formation energies of β-Mg17Al12. These first-principles calculations can provide highly accurate thermodynamic and kinetic information for Mg alloys.

  12. The Integration of a Structural Water Gas Shift Catalyst with a Vanadium Alloy Hydrogen Transport Device

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Thomas; Argyle, Morris; Popa, Tiberiu

    2009-06-30

    This project is in response to a requirement for a system that combines water gas shift technology with separation technology for coal derived synthesis gas. The justification of such a system would be improved efficiency for the overall hydrogen production. By removing hydrogen from the synthesis gas stream, the water gas shift equilibrium would force more carbon monoxide to carbon dioxide and maximize the total hydrogen produced. Additional benefit would derive from the reduction in capital cost of plant by the removal of one step in the process by integrating water gas shift with the membrane separation device. The answer turns out to be that the integration of hydrogen separation and water gas shift catalysis is possible and desirable. There are no significant roadblocks to that combination of technologies. The problem becomes one of design and selection of materials to optimize, or at least maximize performance of the two integrated steps. A goal of the project was to investigate the effects of alloying elements on the performance of vanadium membranes with respect to hydrogen flux and fabricability. Vanadium was chosen as a compromise between performance and cost. It is clear that the vanadium alloys for this application can be produced, but the approach is not simple and the results inconsistent. For any future contracts, large single batches of alloy would be obtained and rolled with larger facilities to produce the most consistent thin foils possible. Brazing was identified as a very likely choice for sealing the membranes to structural components. As alloying was beneficial to hydrogen transport, it became important to identify where those alloying elements might be detrimental to brazing. Cataloging positive and negative alloying effects was a significant portion of the initial project work on vanadium alloying. A water gas shift catalyst with ceramic like structural characteristics was the second large goal of the project. Alumina was added as a

  13. Ultrasmall PdmMn1-mOx binary alloyed nanoparticles on graphene catalysts for ethanol oxidation in alkaline media

    Science.gov (United States)

    Ahmed, Mohammad Shamsuddin; Park, Dongchul; Jeon, Seungwon

    2016-03-01

    A rare combination of graphene (G)-supported palladium and manganese in mixed-oxides binary alloyed catalysts (BACs) have been synthesized with the addition of Pd and Mn metals in various ratios (G/PdmMn1-mOx) through a facile wet-chemical method and employed as an efficient anode catalyst for ethanol oxidation reaction (EOR) in alkaline fuel cells. The as prepared G/PdmMn1-mOx BACs have been characterized by several instrumental techniques; the transmission electron microscopy images show that the ultrafine alloyed nanoparticles (NPs) are excellently monodispersed onto the G. The Pd and Mn in G/PdmMn1-mOx BACs have been alloyed homogeneously, and Mn presents in mixed-oxidized form that resulted by X-ray diffraction. The electrochemical performances, kinetics and stability of these catalysts toward EOR have been evaluated using cyclic voltammetry in 1 M KOH electrolyte. Among all G/PdmMn1-mOx BACs, the G/Pd0.5Mn0.5Ox catalyst has shown much superior mass activity and incredible stability than that of pure Pd catalysts (G/Pd1Mn0Ox, Pd/C and Pt/C). The well dispersion, ultrafine size of NPs and higher degree of alloying are the key factor for enhanced and stable EOR electrocatalysis on G/Pd0.5Mn0.5Ox.

  14. Bi-Sn alloy catalyst for simultaneous morphology and doping control of silicon nanowires in radial junction solar cells

    International Nuclear Information System (INIS)

    Low-melting point metals such as bismuth (Bi) and tin (Sn) are ideal choices for mediating a low temperature growth of silicon nanowires (SiNWs) for radial junction thin film solar cells. The incorporation of Bi catalyst atoms leads to sufficient n-type doping in the SiNWs core that exempts the use of hazardous dopant gases, while an easy morphology control with pure Bi catalyst has never been demonstrated so far. We here propose a Bi-Sn alloy catalyst strategy to achieve both a beneficial catalyst-doping and an ideal SiNW morphology control. In addition to a potential of further growth temperature reduction, we show that the alloy catalyst can remain quite stable during a vapor-liquid-solid growth, while providing still sufficient n-type catalyst-doping to the SiNWs. Radial junction solar cells constructed over the alloy-catalyzed SiNWs have demonstrated a strongly enhanced photocurrent generation, thanks to optimized nanowire morphology, and largely improved performance compared to the reference samples based on the pure Bi or Sn-catalyzed SiNWs

  15. Activity and Stability of Rare Earth-Based Hydride Alloys as Catalysts of Hydrogen Absorption-Oxidation Reactions

    Institute of Scientific and Technical Information of China (English)

    Ying Taokai(应桃开); Gao Xueping(高学平); Hu Weikang(胡伟康); Noréus Dag

    2004-01-01

    Rare earth-based AB5-type hydrogen storage alloys as catalysts of hydrogen-diffusion electrodes for hydrogen absorption and oxidation reactions in alkaline fuel cells were investigated. It is demonstrated that the meta-hydride hydrogen-diffusion electrodes could be charged by hydrogen gas and electrochemically discharged at the same time to retain a stable oxidation potential for a long period. The catalytic activities and stability are almost comparable with a Pt catalyst on the active carbon. Further improvement of performances is expected via reduction of catalyst size into nanometers.

  16. Microstructure evolution during laser-aided direct metal deposition of alloy tool steel

    International Nuclear Information System (INIS)

    Laser-aided direct metal deposition has been used to form an alloy tool steel coating. The microstructure of the deposited material was analyzed by means of scanning electron microscopy and transmission electron microscopy. The formation relationships among martensite, ε-carbide, cementite and austenite in the coating are discussed. The effect of rapid solidification associated with direct metal deposition on lattice parameters is also reported.

  17. Synergistic Effects of Alloying and Thiolate Modification in Furfural Hydrogenation over Cu-Based Catalysts.

    Science.gov (United States)

    Pang, Simon H; Love, Nicole E; Medlin, J Will

    2014-12-01

    Control of bimetallic surface composition and surface modification with self-assembled monolayers (SAMs) represent two methods for modifying catalyst activity and selectivity. However, possible synergistic effects of employing these strategies in concert have not been previously explored. We investigated the effects of modifying Cu/Al2O3 catalysts by alloying with Ni and modifying with octadecanethiol (C18) SAMs, using furfural hydrogenation as a probe reaction. Incorporation of small amounts of Ni (Cu4Ni) improved catalytic activity while slightly reducing hydrogenation selectivity. Further incorporation of Ni resulted in high rates for decarbonylation and ring-opening. Modification of the Cu4Ni catalyst with C18-SAMs resulted in improvement in both the activity and hydrogenation selectivity. X-ray photoelectron spectroscopy experiments on bimetallic thin films and density functional theory calculations revealed that the C18-SAM kinetically stabilized Cu at the surface under hydrogenation conditions. These results indicate that thiolate monolayers can be used to control surface bimetallic composition to improve catalytic performance. PMID:26278941

  18. Improved reversibility in lithium-oxygen battery: Understanding elementary reactions and surface charge engineering of metal alloy catalyst

    Science.gov (United States)

    Kim, Byung Gon; Kim, Hyung-Jin; Back, Seoin; Nam, Kwan Woo; Jung, Yousung; Han, Young-Kyu; Choi, Jang Wook

    2014-02-01

    Most Li-O2 batteries suffer from sluggish kinetics during oxygen evolution reactions (OERs). To overcome this drawback, we take the lesson from other catalysis researches that showed improved catalytic activities by employing metal alloy catalysts. Such research effort has led us to find Pt3Co nanoparticles as an effective OER catalyst in Li-O2 batteries. The superior catalytic activity was reflected in the substantially decreased overpotentials and improved cycling/rate performance compared to those of other catalysts. Density functional theory calculations suggested that the low OER overpotentials are associated with the reduced adsorption strength of LiO2 on the outermost Pt catalytic sites. Also, the alloy catalyst generates amorphous Li2O2 conformally coated around the catalyst and thus facilitates easier decomposition and higher reversibility. This investigation conveys an important message that understanding elementary reactions and surface charge engineering of air-catalysts are one of the most effective approaches in resolving the chronic sluggish charging kinetics in Li-O2 batteries.

  19. The forming of coke by catalytic cracking of black mineral oil by catalysts on the base of activated aluminium alloys

    International Nuclear Information System (INIS)

    The paper deals with an investigation in coke formation under black mineral oil reactions on oxide catalysts which care based on activated aluminium alloys containing 2-20% of active components of In and Ga. The coke yield is of extreme nature and depends on the content of active components in the catalyst composition. The application of thermogravimetric method shows that the oxidation of coke depositions after black mineral oil cracking proceeds in the same temperature range while after the steam-water treatment of coked catalysts the oxidation of coke deposition proceeds at higher temperatures with different temperature maximums which points to the inhomogeneity of coke depositions. It is shown that the catalyst phase composition changes significantly during the reaction under the effect of reaction mixture. 4 refs., 3 figs

  20. Greatly improved electrochemical performance of lithium-oxygen batteries with a bimetallic platinum-copper alloy catalyst

    Science.gov (United States)

    Lee, Minwook; Hwang, Yubin; Yun, Kyung-Han; Chung, Yong-Chae

    2015-08-01

    Research on the cathode catalysts of lithium-oxygen (Li-O2) batteries is one of the most important branches to commercialize these batteries to overcome the sluggish kinetics during both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). In this study, a high performance catalyst based on a bimetallic Pt-Cu alloy is investigated for Li-O2 batteries using first-principles calculation. The theoretical prediction shows that the Pt-Cu alloy is much more effective than the pure Pt according to the electrochemical performance. In particular, the effectiveness of the catalytic property is maximized in the case of the PtCu (111) surface which greatly reduces the large overpotentials of the original Li-O2 batteries during the OER/ORR. It is identified for the first time that the charge overpotentials are affected mainly by the inherent surface charge character of the alloy catalyst. It is observed that the more negatively charged PtCu (111) surface can act as a weakly positively charged surface for the adsorption of Li-O intermediates and thus result in weak ionic bonding of the intermediates on the surface. As a result, the dominant factor improving the catalytic performance is clearly demonstrated, providing insight into the design of an efficient catalyst for Li-O2 battery technologies.

  1. Inuence of Gold-Copper Alloy Catalyst Composition on Crystal Growth and Dopant Distribution in Silicon and Germanium Nanowires

    Science.gov (United States)

    Connell, Justin G.

    A combination of local electrode atom probe tomography (LEAP) and transmission electron microscopy characterization were used to investigate growth of and dopant incorporation in silicon and germanium nanowires (Si and GeNWs) via the vapor-liquid- solid (VLS) mechanism. A sample structure was developed that enabled isolation of the catalyst-mediated contribution to doping in individual nanowires during LEAP analysis. As a result, the distribution coefficient - a thermodynamic quantity describing axial junction abruptness - was measured in nanowires for the first time, providing a fundamental framework for comparison of junction abruptness in nanowires. These investigations also enabled the identification of a previously unknown radial anisotropy in dopant incorporation through the catalyst, with variations in dopant concentration across the VLS-defined diameter of the nanowire as large as two orders of magnitude. Finite element modeling of the doping process, coupled with in situ TEM observations reported in the literature, suggests that this radially inhomogeneous dopant distribution is a direct consequence of growth from a faceted liquid-solid interface, rather than the commonly assumed planar interface. Au-Cu alloy catalysts were explored as alternatives to Au-catalyzed VLS nanowire growth as a means to alleviate or eliminate axial and radial doping gradients in nanowires. Both an aqueous solution and electron beam lithographic method for creating Au-Cu alloy catalysts of controlled composition were developed, and GeNW growth was demonstrated from both types of catalyst. LEAP characterization of Au-Cu alloy catalyzed P-doped GeNWs revealed that alloying with Cu results in more abrupt axial doping junctions, as well as a more homogeneous radial distribution of dopants within the VLS-defined diameter of the nanowire.

  2. Synthesis of graphene through direct decomposition of CO$_2$ with the aid of Ni–Ce–Fe trimetallic catalyst

    Indian Academy of Sciences (India)

    Ghazaleh Allaedini; Siti Masrinda Tasirin; Payam Aminayi

    2016-02-01

    In this study, few-layered graphene (FLG) has been synthesized using the chemical vapour deposition (CVD) method with the aid of a novel Ni–Ce–Fe trimetallic catalyst. Carbon dioxide was used as the carbon source in the present work. The obtained graphene was characterized by Raman spectroscopy, and the results proved that high-quality graphene sheets were obtained. Scanning electron microscopy, atomic force microscopy and transmission electron microscopy pictures were used to investigate the morphology of the prepared FLG. The energydispersive X-ray spectroscopy results confirmed a high yield ($\\sim$48%) of the obtained graphene through this method. Ni–Ce–Fe has been shown to be an active catalyst in the production of high-quality graphene via carbon dioxide decomposition. The X-ray photoelectron spectroscopy spectrum was also obtained to confirm the formation of graphene.

  3. Synthesis and characterization of Pt-Sn-Ni alloys to application as catalysts for direct ethanol fuel cells

    International Nuclear Information System (INIS)

    Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)

  4. A microstructural investigation of gas atomized Raney type Al-27.5 at.% Ni catalyst precursor alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mullis, A.M., E-mail: a.m.mullis@leeds.ac.uk [Institute for Materials Research, University of Leeds, Leeds LS2 9JT (United Kingdom); Bigg, T.D., E-mail: t.bigg@leeds.ac.uk [Institute for Materials Research, University of Leeds, Leeds LS2 9JT (United Kingdom); Adkins, N.J., E-mail: n.j.e.adkins@bham.ac.uk [IRC in Materials Processing, University of Birmingham, Edgbaston, Birmingham B15-2TT (United Kingdom)

    2015-11-05

    Quantitative image analysis has been used to investigate the phase composition of gas atomized powders of a Raney type Ni catalyst precursor alloys of composition Al-27.5 at.% Ni in the powder size range 150–212 μm. We find that there are considerable variations in phase composition both between powders from the same batch and as a function distance from the particle surface within individual particles. Such variations may have significant implications for the future production and uptake of such catalysts, including the necessity for post-production crushing of gas atomized powders. Models are proposed to account for both variations. - Highlights: • The phase composition of powder Raney-Ni catalysts has been investigated. • Image analysis is used to quantify differences between and within particles. • Phase composition can vary by up to 10% between the particle surface and centre. • Differences of up to 10% in the mean composition are also found between particles.

  5. Quantification of zinc atoms in a surface alloy on copper in an industrial-type methanol synthesis catalyst

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Moses, Poul Georg; Sehested, Jens;

    2014-01-01

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel. Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of ZnO as a...... promoter for this type of catalyst is still under intense debate. Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides a consistent...... picture of surface alloying between copper and zinc. This analysis enables a reinterpretation of the methods that have been used for the determination of the Cu surface area and provides an opportunity to independently quantify the specific Cu and Zn areas. This method may also be applied to other systems...

  6. Quantification of zinc atoms in a surface alloy on copper in an industrial-type methanol synthesis catalyst

    DEFF Research Database (Denmark)

    Kuld, Sebastian; Moses, Poul Georg; Sehested, Jens;

    2014-01-01

    Methanol has recently attracted renewed interest because of its potential importance as a solar fuel.1 Methanol is also an important bulk chemical that is most efficiently formed over the industrial Cu/ZnO/Al2O3 catalyst. The identity of the active site and, in particular, the role of ZnO as a...... promoter for this type of catalyst is still under intense debate.2 Structural changes that are strongly dependent on the pretreatment method have now been observed for an industrial-type methanol synthesis catalyst. A combination of chemisorption, reaction, and spectroscopic techniques provides a...... consistent picture of surface alloying between copper and zinc. This analysis enables a reinterpretation of the methods that have been used for the determination of the Cu surface area and provides an opportunity to independently quantify the specific Cu and Zn areas. This method may also be applied to other...

  7. Mechanical alloying of a hydrogenation catalyst used for the remediation of contaminated compounds

    Science.gov (United States)

    Quinn, Jacqueline W. (Inventor); Clausen, Christian A. (Inventor); Geiger, Cherie L. (Inventor); Aitken, Brian S. (Inventor)

    2012-01-01

    A hydrogenation catalyst including a base material coated with a catalytic metal is made using mechanical milling techniques. The hydrogenation catalysts are used as an excellent catalyst for the dehalogenation of contaminated compounds and the remediation of other industrial compounds. Preferably, the hydrogenation catalyst is a bimetallic particle including zero-valent metal particles coated with a catalytic material. The mechanical milling technique is simpler and cheaper than previously used methods for producing hydrogenation catalysts.

  8. AIDS

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/000594.htm HIV/AIDS To use the sharing features on this page, ... immunodeficiency virus (HIV) is the virus that causes AIDS. When a person becomes infected with HIV, the ...

  9. Computer-aided design of a catalyst for Edman degradation utilizing substrate-assisted catalysis

    OpenAIRE

    Borgo, Benjamin; Havranek, James J.

    2014-01-01

    Molecular biology has been revolutionized by the miniaturization and parallelization of DNA sequencing assays previously performed on bulk samples. Many of these technologies rely on biomolecular reagents to facilitate detection, synthesis, or labeling of samples. To aid in the construction of analogous experimental approaches for proteins and peptides, we have used computer-aided design to engineer an enzyme capable of catalyzing the cleavage step of the Edman degradation. We exploit the sim...

  10. A structure investigation of Pt-Co bimetallic catalysts fabricated by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Lucariello, Marialaura; Penazzi, Nerino [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, C.so Duca Abruzzi n. 24, I-10129 Torino (Italy); Arca, Elisabetta; Mulas, Gabriele [Dipartimento di Chimica, Universita di Sassari, Via Vienna n. 2, I-07100 Sassari (Italy); Enzo, Stefano [Dipartimento di Chimica, Universita di Sassari, Via Vienna n. 2, I-07100 Sassari (Italy)], E-mail: enzo@uniss.it

    2009-03-15

    Three Pt-Co mixtures of composition Pt{sub 25}Co{sub 75}, Pt{sub 50}Co{sub 50} and Pt{sub 75}Co{sub 25} respectively, were synthesized using the high-energy ball milling technique of the elemental powders with a view to prepare catalysts for fuel cells. The kinetics of phase evolution, their structure and average microstructure properties were quantitatively investigated by X-ray powder diffraction with the Rietveld method. The results show that the ball milling technique is able to produce Pt-Co solid solutions soon after few minutes of mechanical treatment. Of the two polymorphs of cobalt the fcc allotrope appears to be involved preferentially in the early stage of alloying reaction with fcc platinum. For the three compositions, a sigmoidal equation based on an interdiffusion-controlled mechanism satisfactorily accounts for the evolution of the solid solution as a function of mechanical treatment time. A characteristic reaction time of 3-6 h is observed for the solid state transformation reaction with the milling conditions adopted in our reactor. In the case of the Pt{sub 25}Co{sub 75} composition, a competitive-consecutive reaction is observed. Lattice parameters of the solid solutions after extended times of milling and related atomic volumes turn out to be slightly above the values ideally predicted on the basis of the Vegard's law. For the Pt{sub 75}Co{sub 25} composition the average crystallite size is reduced down to ca. 150 A after 12 h when the lattice microstrain is also at a maximum, but further mechanical treatment increases the average crystal size value and to decrease the strain. Similar results are found for equiatomic and Co-rich compositions. Annealing of the alloyed equiatomic powders promotes a cubic-to-tetragonal transformation which is already operative at 600 deg. C. In fact, after this treatment two tetragonal phases are observed. Further thermal treatment and annealing at 700 deg. C induces peak sharpening of the diffraction patterns

  11. Nanoscale alloying effect of gold–platinum nanoparticles as cathode catalysts on the performance of a rechargeable lithium–oxygen battery

    International Nuclear Information System (INIS)

    The understanding of nanoscale alloying or the phase segregation effect of alloy nanoparticles on the catalytic properties is important for a rational design of the desired catalysts for a specific reaction. This paper describes findings of an investigation into this type of structural effect for carbon-supported bimetallic gold–platinum nanoparticles as cathode catalysts in a rechargeable lithium–oxygen battery. The nanoscale structural characteristics in terms of size, alloying and phase segregation were shown to affect the catalytic properties of the catalysts in the Li–O2 battery. In addition to the composition effect, the catalysts with a fully alloyed phase structure were found to exhibit a smaller discharge–charge voltage difference and a higher discharge capacity than those with a partial phase segregation structure. This finding is significant for the design of alloy nanoparticles as air cathode catalysts in rechargeable lithium–air batteries, demonstrating the importance of the control of the nanoscale composition and phase properties. (paper)

  12. Electro-oxidation of ethanol on ternary non-alloyed Pt-Sn-Pr/C catalysts

    Science.gov (United States)

    Corradini, Patricia G.; Antolini, Ermete; Perez, Joelma

    2015-02-01

    Ternary Pt-Sn-Pr/C (70:10:20), (70:15:15) and (45:45:10) electro-catalysts were prepared by a modified formic acid method, and their activity for the ethanol oxidation reaction (EOR) was compared with that of Pt-Pr/C catalysts prepared by the same methods and that of commercial Pt-Sn/C (75:25) and Pt/C catalysts. Among all the catalysts, the Pt-Sn-Pr/C (45:45:10) catalyst presented both the highest mass activity and the highest specific activity. The steady state electrochemical stability of ternary Pt-Sn-Pr catalysts increased with the surface Sn/Pt atomic ratio. Following repetitive potential cycling (RPC), the activity for ethanol oxidation of Pt-Sn-Pr/C catalysts with high surface Sn/Pt atomic ratio was considerably higher than that of the corresponding as-prepared catalysts, and increased with increasing the Sn/Pt ratio. The increase of the EOR mass activity following RPC was ascribed to the increase of either the specific activity (for the Pt-Sn-Pr/C (70:15:15) catalyst) or the electrochemically active surface area (for the Pt-Sn-Pr/C (45:45:10) catalyst). Dissolution of Sn and Pr oxides from Pt-Sn-Pr/C catalyst surface was observed following RPC.

  13. Multiply twinned AgNi alloy nanoparticles as highly active catalyst for multiple reduction and degradation reactions.

    Science.gov (United States)

    Kumar, Mukesh; Deka, Sasanka

    2014-09-24

    Size dependent surface characteristics of nanoparticles lead to use of these nanomaterials in many technologically important fields, including the field of catalysis. Here Ag(1-x)Ni(x) bimetallic alloy nanoparticles have been developed having a 5-fold twinned morphology, which could be considered as an important alloy because of their excellent and unique catalytic and magnetic properties. Alloying between Ag and Ni atoms on a nanoscale has been confirmed with detailed X-ray diffraction, high resolution transmission electron microscopy, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and magnetization measurements. Although introduced for the first time as a catalyst due to having high active surface sites, the as-synthesized nanoparticles showed one of the best multiple catalytic activity in the industrially important (electro)-catalytic reduction of 4-nitrophenol (4-NP) and 4-nitroaniline (4-NA) to corresponding amines with noticeable reduced reaction time and increased rate constant without the use of any large area support. Additionally the same catalyst showed enhanced catalytic activity in degradation of environment polluting dye molecules. The highest ever activity parameter we report here for Ag0.6Ni0.4 composition is 156 s(-1)g(-1) with an apparent rate constant of 31.1 × 10(-3) s(-1) in a 4-NP reduction reaction where the amount of catalyst used was 0.2 mg and the time taken for complete conversion of 4-NP to 4-aminophenol was 60 s. Similarly, an incredible reaction rate constant (115 s(-1)) and activity parameter (576.6 s(-1)g(-1)) were observed for the catalytic degradation of methyl orange dye where 15 s is the maximum time for complete degradation of the dye molecules. The high catalytic performance of present AgNi alloy NPs over the other catalysts has been attributed to size, structural (twinned defect) and electronic effects. This study may lead to use of these bimetallic nanostructures with excellent recyclable catalytic

  14. Optimization of Pt-Pd alloy catalyst and supporting materials for oxygen reduction in air-cathode Microbial Fuel Cells

    International Nuclear Information System (INIS)

    Highlights: • Pt-Pd alloy catalyst was fabricated on carbon paper via electro-deposition. • MFCs with Pt-Pd cathode of 15 deposition cycles generated a maximum power density. • Graphene decoration did not improve ORR activity of the Pt-Pd electrode. • CNT as the supporting material enhanced ORR activity of the Pt-Pd electrode. • CNT-Pt-Pd cathode demonstrates the potential of replacing Pt catalyst in MFCs. - ABSTRACT: In this study, Pt-Pd alloy catalyst was fabricated on carbon papers via electro-deposition as an alternative catalyst for oxygen reduction in air-cathode Microbial Fuel Cells (MFCs). Effects of electro-deposition cycles and supporting materials (graphene and carbon nanotubes (CNTs)) on oxygen reduction reaction (ORR) activity of the Pt-Pd electrode and power generation in MFCs were investigated. The structural and electrochemical properties of the Pt-Pd catalyst were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results showed that the Pt-Pd electrode showed a good ORR activity. A MFC with a Pt-Pd cathode of 15 deposition cycles produced a maximum power density of 1274 mWm−2, comparable to that with a conventional Pt/C cathode (0.5 mg Pt cm−2). CNT as the supporting material further increased ORR activity of the Pt-Pd electrode and power generation capacity in MFCs, while graphene as the supporting material did not produce positive effects. XRD results confirmed the presence of Pt/Pd elements on the electrode. SEM results showed that decoration using CNT reduced Pt-Pd particle size and promoted them even dispersion on the carbon paper. The Pt-Pd electrode attained a comparable performance to the Pt/C electrode when controlling an optimum deposition cycles and using CNT as the supporting materials, which demonstrates the potential of replacing Pt as an oxygen reduction catalyst in MFCs due to high oxygen reduction activity and relatively low cost

  15. Carbon deposition in the Bosch process with ruthenium and ruthenium-iron alloy catalysts. M.S. Thesis. Final Report, Jan. 1981 - Jul. 1982

    Science.gov (United States)

    Manning, M. P.; Reid, R. C.; Sophonpanich, C.

    1982-01-01

    The effectiveness of ruthenium and the alloys 50Ru50Fe and 33Ru67Fe as alternatives to iron, nickel, and cobalt catalysts in recovering oxygen from metabolic carbon dioxide was investigated. Carbon deposition boundaries over the unsupported alloys are reported. Experiments were also carried out over 50Ru50Fe and 97Ru3Fe3 catalysts supported on gamma-alumina to determine their performance in the synthesis of low molecular weight olefins. High production of ethylene and propylene would be beneficial for an improvement of an overall Bosch process, as a gas phase containing high olefin content would enhance carbon deposition in a Bosch reactor.

  16. Identification of non-precious metal alloy catalysts for selective hydrogenation of acetylene

    DEFF Research Database (Denmark)

    Studt, Felix; Abild-Pedersen, Frank; Bligaard, Thomas; Sørensen, Rasmus Zink; Christensen, Claus H.; Nørskov, Jens Kehlet

    2008-01-01

    The removal of trace acetylene from ethylene is performed industrially by palladium hydrogenation catalysts ( often modified with silver) that avoid the hydrogenation of ethylene to ethane. In an effort to identify catalysts based on less expensive and more available metals, density functional...

  17. Rational Catalyst Design of Titanium-Silica Materials Aided by Site-Specific Titration Tools

    Science.gov (United States)

    Eaton, Todd Robert

    Silica-supported titanium materials are widely used for thermocatalytic applications such as hydroxylation of alkanes and aromatics, oxidation of alcohols and ethers, ammoximation of carbonyls, and sulfoxidations, while Ti-based materials are widely studied for photocatalytic applications such as photo-oxidation of organic substrates and photo-reduction of CO 2. However, the underlying phenomena of how to synthesize, identify, and control the active structures in these materials is not well understood because of the narrow scope of previous work. Studies of titanium-based catalysts typically focus on materials where the metal is present as either highly-dispersed Ti cations or in bulk crystalline TiO2 form, neglecting the numerous and potentially useful intermediate structures. Furthermore, these works typically focus on a single synthesis technique and rely upon bulk characterization techniques to understand the materials. Here rigorous titanium-silica synthesis-structure-function relationships are established by examining several different synthetic method and utilizing characterization techniques that enable an atomic-level understanding of the materials. The materials studied span the range from isolated Ti cations to clustered TiOx domains, polymeric TiO x domains, anatase-like 2D TiO2 domains, and 3D crystalline TiO2. Tools to quantify accessible TiO x and tetrahedral Ti sites are developed, utilizing the selective titration of titanium with phenylphosphonic acid (PPA). Catalytic properties are probed with the photocatalytic oxidation of benzyl alcohol and the thermocatalytic epoxidation of cis-cyclooctene with H2O2 . PPA titration data indicate that the rate of benzyl alcohol photo-oxidation is independent of titanium coordination, while the rate of alkene epoxidation with H2O2 is proportional to the number of tetrahedral titanium sites on the catalyst. PPA titration data also enables the estimation of TiO2 particle size and reveals an important distinction

  18. CFD aided optimization of an innovative SCR catalyst design for heavy-duty marine diesel engines

    Science.gov (United States)

    Krastev, V. K.; Russo, S.; Verdemare, D.; Recine, G.; Biferale, L.; Falcucci, G.

    2016-06-01

    In this paper, the design of a new system for reducing NOx from exhaust gases from marine engines is shown. The core of the system is represented by the Selective Catalytic Reduction (SCR) reactor, in which the catalyst is made of titanium dioxide nano-fibers functionalized with metal oxides and deposited by electrospinning on a corrugated metal support. Compared to the current monolithic reactor designs, the high specific surface offered by the fibers allows in principle to satisfy the TIER III emission standards, with a consistent saving in the reactor volume. To optimize the reactor design process, a Computational Fluid Dynamics (CFD) model has been developed, alongside experimental measurements and numerical simulations. Results of different configurations are reported and critically assessed.

  19. Nitrogen-doped carbon onions encapsulating metal alloys as efficient and stable catalysts for dye-sensitized solar cells

    Science.gov (United States)

    Zhu, Chongyang; Xu, Feng; Chen, Jing; Min, Huihua; Dong, Hui; Tong, Ling; Qasim, Khan; Li, Shengli; Sun, Litao

    2016-01-01

    Designing a new class of non-noble metal catalysts with triiodide reduction activity and stability comparable to those of conventional Pt is extremely significant for the application of dye-sensitized solar cells (DSSCs). Here, we demonstrate newly designed counter electrode (CE) materials of onion-like nitrogen-doped carbon encapsulating metal alloys (ONC@MAs) such as FeNi3 (ONC@FeNi3) or FeCo (ONC@FeCo), by a facile and scalable pyrolysis method. The resulting composite catalysts show superior catalytic activities towards the triiodide reduction and exhibit low charge transfer resistance between the electrode surfaces and electrolytes. As a result, the DSSCs based on ONC@FeCo and ONC@FeNi3 achieve outstanding power conversion efficiencies (PCEs) of 8.26% and 8.87%, respectively, which can rival the 8.28% of Pt-based DSSC. Moreover, the excellent electrochemical stabilities for both the two catalysts also have been corroborated by electrochemical impendence spectra and cyclic voltammetry (CV). Noticeably, TEM investigation further reveals that the N-doped graphitic carbon onions exhibit the high structural stability in iodine-containing medium even subject to hundreds of CV scanning. These results make ONC@MAs the promising candidates to supersede costly Pt as efficient and stable CEs for DSSCs.

  20. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    Directory of Open Access Journals (Sweden)

    Rodiansono Rodiansono

    2015-07-01

    Full Text Available A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, and 0.75. The formation of Ni-Sn alloy species was mainly depended on the composition and temperature of H2 treatment. Intermetallics Ni-Sn that contain Ni3Sn, Ni3Sn2, and Ni3Sn4 alloy phases are known to be effective heterogeneous catalysts for levulinic acid hydrogenation giving very excellence g-valerolactone yield of >99% at 433 K, initial H2 pressure of 4.0 MPa within 6 h. The effective hydrogenation was obtained in H2O without the formation of by-product. Intermetallic Ni-Sn(1.5 that contains Ni3Sn2 alloy species demonstrated very stable and reusable catalyst without any significant loss of its selectivity. © 2015 BCREC UNDIP. All rights reserved. Received: 26th February 2015; Revised: 16th April 2015; Accepted: 22nd April 2015  How to Cite: Rodiansono, R., Astuti, M.D., Ghofur, A., Sembiring, K.C. (2015. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 192-200. (doi:10.9767/bcrec.10.2.8284.192-200Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8284.192-200  

  1. Hydrogenation of furfuryl alcohol to tetrahydrofurfuryl alcohol on NiB/SiO2 amorphous alloy catalyst

    Institute of Scientific and Technical Information of China (English)

    SONG Yun; LI Wei; ZHANG Minghui; TAO Keyi

    2007-01-01

    NiB/SiO2 amorphous alloy catalyst was prepared by power electroless plating method and characterized by induction coupled plasma (ICP),Brunauer-Emmett-Teller method (BET),transmission electron microscope (TEM)and X-ray diffraction (XRD) techniques.The catalytic performance of NiB/SiO2 was investigated for the hydrogenation of furfuryl alcohol (FA) to tetrahydrofurfuryl alcohol (THFA).The effects of operational conditions,such as reaction temperature,pressure,and stirring rate were carefully studied.The proper conditions were determined as the following:pressure 2.0 MPa,temperature 120℃ and stirring rate 550 r/min.A typical result with FA conversion of 99%and THFA selectivity of 100% was obtained under such conditions,which was close to that over Raney Ni.

  2. Computer-aided determinatio of absorption cross section of multicomponent alloys

    International Nuclear Information System (INIS)

    For U alloys with Cu, Mo and Hf, the results are given of computer calculations of changes in the effective absorption cross section for thermal neutrons with composition of the alloys. The program was written in Algol 68 for the TESLA 200 computer. The program may be used for calculating the effective absorption cross section of any alloy consisting of a maximum of 6 components. (E.S.)

  3. Surface structure and chemistry of Pt/Cu/Pt(1 1 1) near surface alloy model catalyst in CO

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Shibi [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Nguyen, Luan; Cheng, Fang [Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Liu, Lacheng [Department of Physics, Nanchang University, Nanchang 350000 (China); Yu, Ying [College of Physical Science and Technology, Central China Normal University, Wuhan 430079 (China); Tao, Franklin, E-mail: franklin.tao.2011@gmail.com [Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2014-11-30

    Graphical abstract: - Abstract: Near surface alloy (NSA) model catalyst Pt/Cu/Pt(1 1 1) was prepared on Pt(1 1 1) through a controlled vapor deposition of Cu atoms. Different coordination environments of Pt atoms of the topmost Pt layer with the underneath Cu atoms in the subsurface result in different local electronic structures of surface Pt atoms. Surface structure and chemistry of the NAS model catalyst in Torr pressure of CO were studied with high pressure scanning tunneling microscopy (HP-STM) and ambient pressure X-ray photoelectron spectroscopy (AP-XPS). In Torr pressure of CO, the topmost Pt layer of Pt/Cu/Pt(1 1 1) is restructured to thin nanoclusters with size of about 1 nm. Photoemission feature of O 1s of CO on Pt/Cu/Pt(1 1 1) suggests CO adsorbed on both edge and surface of these formed nanoclusters. This surface is active for CO oxidation. Atomic layers of carbon are formed on Pt/Cu/Pt(1 1 1) at 573 K in 2 Torr of CO.

  4. Ultrasmall PtSn alloy catalyst for ethanol electro-oxidation reaction

    Science.gov (United States)

    Kwak, Da-Hee; Lee, Young-Woo; Han, Sang-Beom; Hwang, Eui-Tak; Park, Han-Chul; Kim, Min-Cheol; Park, Kyung-Won

    2015-02-01

    To improve the electrocatalytic properties for an ethanol electro-oxidation reaction, modifications of Pt nanocrystallites have been used by alloying with other elements such as Ru, Sn, and Au. Here we demonstrate carbon supported Pt3Sn alloy electrocatalyst (Pt3Sn/C) synthesized using a thermal-decomposition method. The PtSn/C prepared by the present synthetic process shows a homogeneous distribution of ultrasmall alloy nanoparticles (∼2.5 nm) in the presence of Pt and Sn metallic states. At 0.45 V, the Pt3Sn/C (0.35 mA cm-2) exhibits much higher current density as compared with Pt/C (0.13 mA cm-2). In an electrochemical stability test, the Pt3Sn/C supported quite high current density and thus showed 3% current reduction after the stability test.

  5. Catalytic Hydrogenation of Levulinic Acid in Water into g-Valerolactone over Bulk Structure of Inexpensive Intermetallic Ni-Sn Alloy Catalysts

    OpenAIRE

    Rodiansono Rodiansono; Maria Dewi Astuti; Abdul Ghofur; Kiky C. Sembiring

    2015-01-01

    A bulk structure of inexpensive intermetallic nickel-tin (Ni-Sn) alloys catalysts demonstrated highly selective in the hydrogenation of levulinic acid in water into g-valerolactone. The intermetallic Ni-Sn catalysts were synthesized via a very simple thermochemical method from non-organometallic precursor at low temperature followed by hydrogen treatment at 673 K for 90 min. The molar ratio of nickel salt and tin salt was varied to obtain the corresponding Ni/Sn ratio of 4.0, 3.0, 2.0, 1.5, a...

  6. Intermetallic Alloys as CO Electroreduction Catalysts-Role of Isolated Active Sites

    DEFF Research Database (Denmark)

    Karamad, Mohammadreza; Tripkovic, Vladimir; Rossmeisl, Jan

    2014-01-01

    potentially selective intermetallic surfaces on which CO can be reduced to methanol at potentials comparable to or even slightly positive than those for CO/CO2 reduction to methane on Cu. Common features shared by most of the selective alloys are single TM sites. The role of single sites is to block parasitic...

  7. Computational Modeling aided Near Net Shape Manufacturing for Aluminum Alloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will focus on developing and validating computational models for near-net shape processing of aluminum alloys. Computational models will be developed...

  8. Alloy hydride catalyst route for the synthesis of single-walled carbon nanotubes, multi-walled carbon nanotubes and magnetic metal-filled multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    This paper presents a novel, cost-effective and single-step technique for the synthesis of single-walled carbon nanotubes (SWNTs), multi-walled carbon nanotubes (MWNTs) and magnetic metal-filled MWNTs using a fixed bed reaction thermal chemical vapour deposition (CVD) using alloy hydride catalyst. The single-step method involves the pyrolysis of methane at suitable temperatures over fine powders of certain Mischmetal-based AB3 alloy hydride catalysts, prepared through the hydrogen decrepitation technique. These carbon nanostructures have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray analysis (EDAX), thermo-gravimetric analysis (TGA) and Raman spectroscopy. The magnetic properties of these metal-filled MWNTs have been studied by vibrating sample magnetometry, and the results are discussed

  9. Nitrogen-doped graphene/CoNi alloy encased within bamboo-like carbon nanotube hybrids as cathode catalysts in microbial fuel cells

    Science.gov (United States)

    Hou, Yang; Yuan, Heyang; Wen, Zhenhai; Cui, Shumao; Guo, Xiaoru; He, Zhen; Chen, Junhong

    2016-03-01

    Cost-effective catalysts are of key importance to the successful deployment of microbial fuel cells (MFCs) for electricity generation from organic wastes. Herein, a novel catalyst prepared by one-step synthesis strategy is reported. The catalyst features N-doped bamboo-like carbon nanotube (BCNT) in which CoNi-alloy is encapsulated at the end and/or the middle section of the tube with many graphene layers inside inner cavities of BCNT (N-G@CoNi/BCNT). The prepared N-G@CoNi/BCNT exhibits a high oxygen reduction reaction (ORR) activity with an early onset potential of 0.06 V vs. Ag/AgCl and a comparable exchange current density to that of commercial Pt/C. The excellent catalytic activity is further evidenced by a high electron transfer number of 3.63. When being applied in MFCs, the N-G@CoNi/BCNT yields an average current density of 6.7 A m-2, slightly lower than that of Pt/C but with a less mass transfer potential loss. The cost of the N-G@CoNi/BCNT for constructing a 1-m2 cathode electrode is 200 times lower than that of Pt/C. With such a competitive price and excellent electrocatalytic-activity resulting from its unique morphology, CoNi-alloy/nitrogen dopants, considerable specific surface area, and carbon-coated alloy/graphene hybridization, the present catalyst is a promising candidate for ORR catalysts in MFCs for energy recovery from wastes.

  10. A Platinum Monolayer Core-Shell Catalyst with a Ternary Alloy Nanoparticle Core and Enhanced Stability for the Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Haoxiong Nan

    2015-01-01

    Full Text Available We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core. The core-shell Pd1Ir1Ni2@Pt/C catalyst exhibits excellent oxygen reduction reaction activity, yielding a mass activity significantly higher than that of Pt monolayer catalysts containing PdIr or PdNi nanoparticles as cores and four times higher than that of a commercial Pt/C electrocatalyst. In 0.1 M HClO4, the half-wave potential reaches 0.91 V, about 30 mV higher than that of Pt/C. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst. We suggest that the porous structure resulting from the dissolution of Ni in the alloy nanoparticles may be the main reason for the catalyst’s enhanced performance.

  11. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    was inspired by a computational screening, suggesting that alloys such as Ni-Fe, Co-Ni, and Co-Fe should show superior activity to the industrially used nickel catalyst. Especially the Ni-Fe system was considered to be interesting, since such alloy catalysts should be both more active and cheaper than...... turned out to work well, and the best catalyst prepared had a C5+ yield almost a factor of two higher than a standard air calcined Co catalyst. In the NH3-SCR reaction it is desirable to develop an active and stable catalyst for NOx removal in automotive applications, since the traditionally used...

  12. Formation and Characterization of Pd, Pt and Pd-Pt Alloy Films on Polyimide by Catalyst-Enhanced Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jinlan; CHENG Yinhua; Yousuf Hamadan; YU Kaichao

    2007-01-01

    Platinum, palladium and their alloy films on polyimide were formed by catalyst-enhanced chemical vapor deposition (CVD) in the carrier gas (N2, O2) at 220-300 ℃ under reduced pressure and normal pressure. The deposition of palladium complexes [ Pd((η3-allyl)(hfac) and Pd(hfac)2 ] gives pure palladium film,while the deposition of platinum needs the enhancement of palladium complex by mixing precursor platinum complex Pt(COD)Me2 and palladium complex in the same chamber. The co-deposition of Pd and Pt metals was used for the deposition of alloy films. During the CVD of palladium-platinum alloy, the Pd/Pt atomic ratios vary under different co-deposition conditions. These metal films were characterized by XPS and SEM, and show a good adhesive property.

  13. CuAu–ZnO–graphene nanocomposite: A novel graphene-based bimetallic alloy-semiconductor catalyst with its enhanced photocatalytic degradation performance

    International Nuclear Information System (INIS)

    Graphical abstract: In this work, we have successfully synthesized a novel graphene-based bimetallic alloy-semiconductor catalyst: CuAu–ZnO–Gr nanocomposite, and which behaved an enhanced photocatalytic activity. - Highlights: • A bimetallic alloy-based catalyst: CuAu–ZnO–Gr is synthesized. • CuAu–ZnO–Gr behaves an enhanced photocatalytic activity. • The detailed explanation of photocatalytic mechanism of CuAu–ZnO–Gr. - Abstract: The bimetallic alloy CuAu nanoparticles (NPs) can produce more photogenerated electrons when compared with single metal Au NPs. Moreover, graphene (Gr) sheets can help the charge separation and slow down the recombination of the electron hole pairs of ZnO. Hence, a novel graphene-based bimetallic alloy-semiconductor catalyst: CuAu–ZnO–Gr nanocomposite is synthesized. Due to the synergistic effect among CuAu NPs, ZnO nanopyramids, and Gr sheets, CuAu–ZnO–Gr behaves an enhanced photocatalytic activity for the photocatalytic degradation of synthetic colorants methyl orange (MO), methylene blue (MB), indigotin (IN), sunset yellow (SY), and tartrazine (TT) under the simulated sunlight irradiation. Furthermore, the apparent rate constants (kapp) of MO, MB, IN, SY, and TT degradation are estimated respectively. In addition, the as-prepared CuAu–ZnO–Gr nanocomposite is characterized by X-ray diffraction, UV–vis spectrum, transmission electron microscopy, energy dispersive X-ray analysis (EDX), and EDX mapping. As a result of the facile synthesis route and the enhanced photocatalytic activity, this new material CuAu–ZnO–Gr can be a promising photocatalyst for the degradation of dyes

  14. CuAu–ZnO–graphene nanocomposite: A novel graphene-based bimetallic alloy-semiconductor catalyst with its enhanced photocatalytic degradation performance

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Hong [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Ye, Xiaoliang [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Duan, Kaiyue; Xue, Muyin; Du, Yongling; Ye, Weichun [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Wang, Chunming, E-mail: wangcm@lzu.edu.cn [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2015-07-05

    Graphical abstract: In this work, we have successfully synthesized a novel graphene-based bimetallic alloy-semiconductor catalyst: CuAu–ZnO–Gr nanocomposite, and which behaved an enhanced photocatalytic activity. - Highlights: • A bimetallic alloy-based catalyst: CuAu–ZnO–Gr is synthesized. • CuAu–ZnO–Gr behaves an enhanced photocatalytic activity. • The detailed explanation of photocatalytic mechanism of CuAu–ZnO–Gr. - Abstract: The bimetallic alloy CuAu nanoparticles (NPs) can produce more photogenerated electrons when compared with single metal Au NPs. Moreover, graphene (Gr) sheets can help the charge separation and slow down the recombination of the electron hole pairs of ZnO. Hence, a novel graphene-based bimetallic alloy-semiconductor catalyst: CuAu–ZnO–Gr nanocomposite is synthesized. Due to the synergistic effect among CuAu NPs, ZnO nanopyramids, and Gr sheets, CuAu–ZnO–Gr behaves an enhanced photocatalytic activity for the photocatalytic degradation of synthetic colorants methyl orange (MO), methylene blue (MB), indigotin (IN), sunset yellow (SY), and tartrazine (TT) under the simulated sunlight irradiation. Furthermore, the apparent rate constants (k{sub app}) of MO, MB, IN, SY, and TT degradation are estimated respectively. In addition, the as-prepared CuAu–ZnO–Gr nanocomposite is characterized by X-ray diffraction, UV–vis spectrum, transmission electron microscopy, energy dispersive X-ray analysis (EDX), and EDX mapping. As a result of the facile synthesis route and the enhanced photocatalytic activity, this new material CuAu–ZnO–Gr can be a promising photocatalyst for the degradation of dyes.

  15. Solid-state-reaction synthesis of cotton-like CoB alloy at room temperature as a catalyst for hydrogen generation.

    Science.gov (United States)

    Wang, Xingpu; Liao, Jinyun; Li, Hao; Wang, Hui; Wang, Rongfang

    2016-08-01

    A novel room-temperature solid-state reaction is developed to synthesize cotton-like CoB alloy (CoBSSR) catalysts with a large specific surface area of 222.4m(2)g(-1). In the hydrolysis of ammonia borane catalyzed by the CoBSSR, the rate of hydrogen generation can reach 68.7mLmin(-1) with a turnover frequency (TOF) value of ca. 6.9Lhydrogenmin(-1)gcatalyst(-1) at 25°C. The TOF value is about 2 times as large as that of CoB alloy prepared by a regular solid-state reaction, which is also much higher than those of the CoB catalysts recently reported in the literature. The activation energy of the hydrolysis of ammonia borane catalyzed by the CoBSSR is as low as 22.78kJmol(-1), hinting that the CoBSSR possesses high catalytic activity, which may be attributed to the large specific surface area and the abundant porous structure. The high catalytic performance, good recoverability and low cost of the CoBSSR enable it to be a promissing catalyst condidate in the hydrolysis of ammonia borane for hydrogen production in commercial application. PMID:27163841

  16. AuPt Alloy on TiO2: A Selective and Durable Catalyst for L-Sorbose Oxidation to 2-Keto-Gulonic Acid.

    Science.gov (United States)

    Chan-Thaw, Carine E; Chinchilla, Lidia E; Campisi, Sebastian; Botton, Gianluigi A; Prati, Laura; Dimitratos, Nikolaos; Villa, Alberto

    2015-12-21

    Pt nanoparticles were prepared by a sol immobilization route, deposited on supports with different acid/base properties (MgO, activated carbon, TiO2 , Al2O3, H-Mordenite), and tested in the selective oxidation of sorbose to 2-keto-gulonic acid (2-KGUA), an important precursor for vitamin C. In general, as the basicity of the support increased, a higher catalytic activity occurred. However, in most cases, a strong deactivation was observed. The best selectivity to 2-KGUA was observed with acidic supports (TiO2 and H-Mordenite) that were able to minimize the formation of C1/C2 products. We also demonstrated that, by alloying Pt to Au, it is possible to enhance significantly the selectivity of Pt-based catalysts. Moreover, the AuPt catalyst, unlike monometallic Pt, showed good stability in recycling because of the prevention of metal leaching during the reaction. PMID:26611807

  17. In Situ Fabrication of PtCo Alloy Embedded in Nitrogen-Doped Graphene Nanopores as Synergistic Catalyst for Oxygen Reduction Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Xing; Wang, Lei; Zhou, Hu; Qin, Yingying; Xu, Wenlei; Jiang, Yu; Sun, Youyi; Shi, Zheqi; Zhuang, Guilin; Li, Xiaonian; Mei, Donghai; Wang, Jian-guo

    2015-11-23

    A novel PtCo alloy in situ etched and embedded in graphene nanopores (PtCo/NPG) as a high-performance catalyst for ORR was reported. Graphene nanopores were fabricated in situ while forming PtCo nanoparticles that were uniformly embedded in the graphene nanopores. Given the synergistic effect between PtCo alloy and nanopores, PtCo/NPG exhibited 11.5 times higher mass activity than that of the commercial Pt/C cathode electrocatalyst. DFT calculations indicated that the nanopores in NPG cannot only stabilize PtCo nanoparticles but can also definitely change the electronic structures, thereby change its adsorption abilities. This enhancement can lead to a favorable reaction pathway on PtCo/NPG for ORR. This study showed that PtCo/NPG is a potential candidate for the next generation of Pt-based catalysts in fuel cells. This study also offered a promising alternative strategy and enabled the fabrication of various kinds of metal/graphene nanopore nanohybrids with potential applications in catalysts and potential use for other technological devices. The authors acknowledge the financial support from the National Basic Research Program (973 program, No. 2013CB733501), Zhejiang Provincial Education Department Research Program (Y201326554) and the National Natural Science Foundation of China (No. 21306169, 21101137, 21136001, 21176221 and 91334013). D. Mei acknowledges the support from the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. Computing time was granted by the grand challenge of computational catalysis of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) and by the National Energy Research Scientific Computing Center (NERSC).

  18. Carbon nanotube-supported Au-Pd alloy with cooperative effect of metal nanoparticles and organic ketone/quinone groups as a highly efficient catalyst for aerobic oxidation of amines.

    Science.gov (United States)

    Deng, Weiping; Chen, Jiashu; Kang, Jincan; Zhang, Qinghong; Wang, Ye

    2016-05-21

    Functionalised carbon nanotube (CNT)-supported Au-Pd alloy nanoparticles were highly efficient catalysts for the aerobic oxidation of amines. We achieved the highest turnover frequencies (>1000 h(-1)) for the oxidative homocoupling of benzylamine and the oxidative dehydrogenation of dibenzylamine. We discovered a cooperative effect between Au-Pd nanoparticles and ketone/quinone groups on CNTs. PMID:27125360

  19. Ordered alloy formation for Pt3Fe/C, PtFe/C and Pt5.75Fe5.75Cuy/CO2-reduction electro-catalysts

    International Nuclear Information System (INIS)

    Carbon supported Pt3Fe, PtFe and Pt5.75Fe5.75Cu catalysts are prepared via the impregnation of Fe and/or Cu-nitrate precursor salts onto a preformed nano-sized Pt/C catalyst. They are referred to as Pt3Fe/C, PtFe/C and Pt5.75Fe5.75Cu/C catalysts and the subscripts refer to the nominal Pt, Fe and Cu atomic ratios. The final catalysts are obtained by annealing the impregnated samples in a H2 enriched atmosphere. Pt5.75Fe6.75/C, Pt5.75Cu6.75/C and Pt5.75Fe5.75Cu2/C catalysts were also made. The as-prepared catalysts are characterized using X-ray diffraction, transmission electron microscopy, standard electrochemical methods and probed for the electrochemical O2 reduction reaction (orr). Rietveld analyses reveal that [Fm-3m] Pt, cubic [Pm-3m] Pt3Fe and tetragonal [P4/mmm] PtFe structure types are made. In case of the Pt5.75Fe5.75Cu/C catalyst, a nano-sized carbon-supported single-phase catalyst of [P4/mmm] structure is found to be made at 800 °C, with Pt and Fe ordered on separate lattice planes, while Cu is distributed randomly onto both Pt and Fe atomic planes. The PtFe/C equivalent catalyst contains in addition a separate Fe phase as well as a slightly disordered [P4/mmm] phase. Pt5.75Cu6.75/C forms a disordered cubic [Fm-3m] alloy structure. The activity toward the orr was measured after 70 potential cycling, which can cause beneficial changes to the catalysts. In case of the specific orr activity, a dependence on the catalyst series is observed as follows: Pt5.75Fe5.75Cu/C [P4/mmm] > PtFe/C [P4/mmm] > Pt3Fe/C [Pm-3 m] ≈ Pt5.75Cu6.75/C [Fm-3m] > Pt/C [Fm-3m]. The highest orr mass activities are also found for the Pt5.75Fe5.75Cu/C and subsequently for the PtFe/C catalysts. Estimated orr activities are well within the range reported in the literature. In fact the specific orr activities compare to results reported for so called de-alloyed catalyst that are among the highest orr mass activities reported in the recent literature.

  20. Widely tunable alloy composition and crystal structure in catalyst-free InGaAs nanowire arrays grown by selective area molecular beam epitaxy

    Science.gov (United States)

    Treu, J.; Speckbacher, M.; Saller, K.; Morkötter, S.; Döblinger, M.; Xu, X.; Riedl, H.; Abstreiter, G.; Finley, J. J.; Koblmüller, G.

    2016-02-01

    We delineate the optimized growth parameter space for high-uniformity catalyst-free InGaAs nanowire (NW) arrays on Si over nearly the entire alloy compositional range using selective area molecular beam epitaxy. Under the required high group-V fluxes and V/III ratios, the respective growth windows shift to higher growth temperatures as the Ga-content x(Ga) is tuned from In-rich to Ga-rich InGaAs NWs. Using correlated x-ray diffraction, transmission electron microscopy, and micro-photoluminescence spectroscopy, we identify structural defects to govern luminescence linewidths in In-rich (x(Ga) 0.6) NWs, whereas limitations at intermediate Ga-content (0.4 blue-shifted to red-shifted photoluminescence emission relative to the band edge emission of the bulk ZB InGaAs phase.

  1. Widely tunable alloy composition and crystal structure in catalyst-free InGaAs nanowire arrays grown by selective area molecular beam epitaxy

    International Nuclear Information System (INIS)

    We delineate the optimized growth parameter space for high-uniformity catalyst-free InGaAs nanowire (NW) arrays on Si over nearly the entire alloy compositional range using selective area molecular beam epitaxy. Under the required high group-V fluxes and V/III ratios, the respective growth windows shift to higher growth temperatures as the Ga-content x(Ga) is tuned from In-rich to Ga-rich InGaAs NWs. Using correlated x-ray diffraction, transmission electron microscopy, and micro-photoluminescence spectroscopy, we identify structural defects to govern luminescence linewidths in In-rich (x(Ga) < 0.4) and Ga-rich (x(Ga) > 0.6) NWs, whereas limitations at intermediate Ga-content (0.4 < x(Ga) < 0.6) are mainly due to compositional inhomogeneities. Most remarkably, the catalyst-free InGaAs NWs exhibit a characteristic transition in crystal structure from wurtzite to zincblende (ZB) dominated phase near x(Ga) ∼ 0.4 that is further reflected in a cross-over from blue-shifted to red-shifted photoluminescence emission relative to the band edge emission of the bulk ZB InGaAs phase

  2. Widely tunable alloy composition and crystal structure in catalyst-free InGaAs nanowire arrays grown by selective area molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Treu, J., E-mail: Julian.Treu@wsi.tum.de, E-mail: Gregor.Koblmueller@wsi.tum.de; Speckbacher, M.; Saller, K.; Morkötter, S.; Xu, X.; Riedl, H.; Abstreiter, G.; Finley, J. J.; Koblmüller, G., E-mail: Julian.Treu@wsi.tum.de, E-mail: Gregor.Koblmueller@wsi.tum.de [Walter Schottky Institut, Physik Department, Center of Nanotechnology and Nanomaterials, Technische Universität München, Am Coulombwall 4, Garching 85748 (Germany); Döblinger, M. [Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, Munich 81377 (Germany)

    2016-02-01

    We delineate the optimized growth parameter space for high-uniformity catalyst-free InGaAs nanowire (NW) arrays on Si over nearly the entire alloy compositional range using selective area molecular beam epitaxy. Under the required high group-V fluxes and V/III ratios, the respective growth windows shift to higher growth temperatures as the Ga-content x(Ga) is tuned from In-rich to Ga-rich InGaAs NWs. Using correlated x-ray diffraction, transmission electron microscopy, and micro-photoluminescence spectroscopy, we identify structural defects to govern luminescence linewidths in In-rich (x(Ga) < 0.4) and Ga-rich (x(Ga) > 0.6) NWs, whereas limitations at intermediate Ga-content (0.4 < x(Ga) < 0.6) are mainly due to compositional inhomogeneities. Most remarkably, the catalyst-free InGaAs NWs exhibit a characteristic transition in crystal structure from wurtzite to zincblende (ZB) dominated phase near x(Ga) ∼ 0.4 that is further reflected in a cross-over from blue-shifted to red-shifted photoluminescence emission relative to the band edge emission of the bulk ZB InGaAs phase.

  3. Thermodynamic Constraints in Using AuM (M = Fe, Co, Ni, and Mo) Alloys as N2 Dissociation Catalysts: Functionalizing a Plasmon-Active Metal.

    Science.gov (United States)

    Martirez, John Mark P; Carter, Emily A

    2016-02-23

    The Haber-Bosch process for NH3 synthesis is arguably one of the greatest inventions of the 20th century, with a massive footprint in agriculture and, historically, warfare. Current catalysts for this reaction use Fe for N2 activation, conducted at high temperatures and pressures to improve conversion rate and efficiency. A recent finding shows that plasmonic metal nanoparticles can either generate highly reactive electrons and holes or induce resonant surface excitations through plasmonic decay, which catalyze dissociation and redox reactions under mild conditions. It is therefore appealing to consider AuM (M = Fe, Co, Ni, and Mo) alloys to combine the strongly plasmonic nature of Au and the catalytic nature of M metals toward N2 dissociation, which together might facilitate ammonia production. To this end, through density functional theory, we (i) explore the feasibility of forming these surface alloys, (ii) find a pathway that may stabilize/deactivate surface M substituents during fabrication, and (iii) define a complementary route to reactivate them under operational conditions. Finally, we evaluate their reactivity toward N2, as well as their ability to support a pathway for N2 dissociation with a low thermodynamic barrier. We find that AuFe possesses similar appealing qualities, including relative stability with respect to phase separation, reversibility of Fe oxidation and reduction, and reactivity toward N2. While AuMo achieves the best affinity toward N2, its strong propensity toward oxidation could greatly limit its use. PMID:26831377

  4. CVD growth of carbon nanotubes on thin-film Ni20Ti35N45 alloy catalyst

    Science.gov (United States)

    Gromov, D. G.; Pavlov, A. A.; Skorik, S. N.; Trifonov, A. Yu.; Shulyat'ev, A. S.

    2015-12-01

    The possibility of forming carbon nanotube (CNT) arrays on a Ni-Ti-N catalytic alloy with low nickel content by chemical vapor deposition (CVD) is demonstrated. Adding nitrogen to the Ni-Ti alloy composition favors the formation of TiN compound and segregation of Ni on the surface, where it produces a catalytic effect on the CNT growth. It is found that, using CVD from acetylene gas phase at a substrate temperature of 650°C, a CNT array of 9-µm height can be grown for 2 min.

  5. A novel Pt-Co alloy hydrogen anode catalyst with superlative activity, CO-tolerance and robustness

    Science.gov (United States)

    Shi, G. Y.; Yano, H.; Tryk, D. A.; Watanabe, M.; Iiyama, A.; Uchida, H.

    2016-07-01

    PtCo nanoparticles, having two atomic layers of stabilized Pt skin, supported on carbon black (Pt2AL-PtCo/C), exhibited superlative mass activity for the CO-tolerant hydrogen oxidation reaction (HOR), together with high robustness with respect to air exposure, as a novel anode catalyst in reformate gas-based polymer electrolyte fuel cells. The high area-specific HOR activity and CO tolerance are consistent with DFT calculations.PtCo nanoparticles, having two atomic layers of stabilized Pt skin, supported on carbon black (Pt2AL-PtCo/C), exhibited superlative mass activity for the CO-tolerant hydrogen oxidation reaction (HOR), together with high robustness with respect to air exposure, as a novel anode catalyst in reformate gas-based polymer electrolyte fuel cells. The high area-specific HOR activity and CO tolerance are consistent with DFT calculations. Electronic supplementary information (ESI) available: Experimental details, TEM images and particle size distribution histograms of all catalysts, and details of the DFT calculations. See DOI: 10.1039/c6nr00778c

  6. Synthesis and characterization of Pt-Sn-Ni alloys to application as catalysts for direct ethanol fuel cells; Sintese e caracterizacao de ligas de Pt-Sn-Ni para aplicacao como caztalisadores em celulas a combustivel do tipo DEFC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.L. da; Correa, P.S.; Oliveira, E.L. de; Takimi, A.S.; Malfatti, C.F., E-mail: celia.malfatti@ufrgs.b [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica. Lab. de Pesquisa em Corrosao; Radtke, C. [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica

    2010-07-01

    Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)

  7. Correlation between diffusion barriers and alloying energy in binary alloys

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg; Rossmeisl, Jan; Stephens, Ifan; Schiøtz, Jakob

    2016-01-01

    In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells.......In this paper, we explore the notion that a negative alloying energy may act as a descriptor for long term stability of Pt-alloys as cathode catalysts in low temperature fuel cells....

  8. Examining the surfaces in used platinum catalysts

    OpenAIRE

    Trumić B.; Stanković D.; Trujić V.

    2009-01-01

    For the purpose of finding more advanced platinum catalyst manufacturing technologies and achieving a higher degree of ammonia oxidation, metallographic characterization has been done on the surface of catalyst gauzes and catalyst gripper gauzes made from platinum and palladium alloys. For the examined samples of gauzes as well as the cross section of the wires, a chemical analysis was provided. The purpose of this paper is the metallographic characterization of examined alloys carried out by...

  9. Supported molten-metal catalysts

    Science.gov (United States)

    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.

  10. CO methanation over supported bimetallic Ni-Fe catalysts: From computational studies towards catalyst optimization

    DEFF Research Database (Denmark)

    Kustov, Arkadii; Frey, Anne Mette; Larsen, Kasper Emil;

    2007-01-01

    DFT calculations combined with a computational screening method have previously shown that bimetallic Ni-Fe alloys should be more active than the traditional Ni-based catalyst for CO methanation. That was confirmed experimentally for a number of bimetallic Ni-Fe catalysts supported on MgAl2O4. He...

  11. Homogeneous catalysts

    CERN Document Server

    Chadwick, John C; Freixa, Zoraida; van Leeuwen, Piet W N M

    2011-01-01

    This first book to illuminate this important aspect of chemical synthesis improves the lifetime of catalysts, thus reducing material and saving energy, costs and waste.The international panel of expert authors describes the studies that have been conducted concerning the way homogeneous catalysts decompose, and the differences between homogeneous and heterogeneous catalysts. The result is a ready reference for organic, catalytic, polymer and complex chemists, as well as those working in industry and with/on organometallics.

  12. Bimetallic Catalysts.

    Science.gov (United States)

    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…

  13. Rhenium Nanochemistry for Catalyst Preparation

    Directory of Open Access Journals (Sweden)

    Vadim G. Kessler

    2012-08-01

    Full Text Available The review presents synthetic approaches to modern rhenium-based catalysts. Creation of an active center is considered as a process of obtaining a nanoparticle or a molecule, immobilized within a matrix of the substrate. Selective chemical routes to preparation of particles of rhenium alloys, rhenium oxides and the molecules of alkyltrioxorhenium, and their insertion into porous structure of zeolites, ordered mesoporous MCM matrices, anodic mesoporous alumina, and porous transition metal oxides are considered. Structure-property relationships are traced for these catalysts in relation to such processes as alkylation and isomerization, olefin metathesis, selective oxidation of olefins, methanol to formaldehyde conversion, etc.

  14. Manufacture of Catalyst Systems for Ammonia Conversion

    Institute of Scientific and Technical Information of China (English)

    GAKH S.V.; SAVENKOV D.A.

    2012-01-01

    Platinum catalyst gauzes have been in use since the moment of development of the process of catalyst oxidation of ammonia for production of nitric acid or hydrocyanic acid.Catalyst gauzes are usually made of platinum or its alloys with rhodium and palladium.These precious metals have remarkable properties that make them ideal catalysts for acceleration of the ammonia/oxygen reaction.In 2008,OJSC "SIC ‘Supermetal’" and Umicore AG&Co.KG launched a production line for Pt-alloy-based catalyst systems to be used for ammonia oxidation in the production of weak nitric acid.Catalyst systems consist of a pack of catalyst gauzes and a pack of catchment gauzes,which are made using flat-bed knitting machines and wire-cloth looms.Today,up-to-date catalyst systems MKSpreciseTM are being manufactured,the basic advantages of which are an individual structure of gauzes and composition of the material,which allows to define precisely the position of each gauze in the catalyst pack,a high activity of the catalyst pack,direct catching of platinum and rhodium in the catalyst system,and a reasonable combination of single- and multilayer types of gauzes.This makes it possible to vary the configuration of the catalyst and select an optimum composition of the system to ensure the maximum efficiency of the ammonia oxidation process.We also produce the catchment systems that allow to find the best decision from the economic point view for each individual case.

  15. Photo-oxidation catalysts

    Science.gov (United States)

    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.

  16. First-principles-aided design of a new Ni-base superalloy: Influence of transition metal alloying elements on grain boundary and bulk cohesion

    International Nuclear Information System (INIS)

    A new approach to the design of Ni-base polycrystalline superalloys is proposed. In this approach, we assume that the creep–rupture characteristics of a superalloy are mostly determined by the strength of interatomic bonding at grain boundaries (GBs) and in the bulk of γ matrix. The ideal work of separation, Wsep, of a GB is used as a fundamental thermodynamic quantity that controls the mechanical strength of an interface, whereas the partial cohesive energy, χ, of an alloy component serves to characterize its contribution into the strength of the bulk. Using the Σ5 (2 1 0)[1 0 0] symmetric tilt GB as a representative high-angle GB in Ni, we calculate Wsep,χ, and GB segregation energies, Eseg, for the complete set of 4d and 5d transition metal impurities, to which we add B (a typical microalloying addition), S and Bi (notoriously known as harmful impurities in Ni-base superalloys). The purpose of the analysis is to identify the elements that demonstrate a high tendency to segregate to GBs, have positive (preferably high) partial cohesive energies in the bulk, and have positive impact on Wsep of GBs. We refer to these elements as low-alloying additions. Our study reveals Zr, Hf, Nb, Ta and B as the most promising low-alloying additions. Our next step is to introduce the elements found in the first step into a new powder metallurgy (P/M) Ni-base superalloy. The results of the subsequent testing confirm that the newly created P/M superalloy indeed demonstrates superior mechanical properties at high temperatures compared to the existing Russian P/M alloy EP741NP

  17. Discovery of technical methanation catalysts based on computational screening

    DEFF Research Database (Denmark)

    Sehested, Jens; Larsen, Kasper Emil; Kustov, Arkadii;

    2007-01-01

    Methanation is a classical reaction in heterogeneous catalysis and significant effort has been put into improving the industrially preferred nickel-based catalysts. Recently, a computational screening study showed that nickel-iron alloys should be more active than the pure nickel catalyst and at ...

  18. Aid Effectiveness

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    Controversy over the aggregate impact of foreign aid has focused on reduced form estimates of the aid-growth link. The causal chain, through which aid affects developmental outcomes including growth, has received much less attention. We address this gap by: (i) specifying a structural model of the...... main relationships; (ii) estimating the impact of aid on a range of final and intermediate outcomes; and (iii) quantifying a simplied representation of the full structural form, where aid impacts on growth through key intermediate outcomes. A coherent picture emerges: aid stimulates growth and reduces...

  19. Catalysts for Efficient Production of Carbon Nanotubes

    Science.gov (United States)

    Sun, Ted X.; Dong, Yi

    2009-01-01

    Several metal alloys have shown promise as improved catalysts for catalytic thermal decomposition of hydrocarbon gases to produce carbon nanotubes (CNTs). Heretofore almost every experiment on the production of carbon nanotubes by this method has involved the use of iron, nickel, or cobalt as the catalyst. However, the catalytic-conversion efficiencies of these metals have been observed to be limited. The identification of better catalysts is part of a continuing program to develop means of mass production of high-quality carbon nanotubes at costs lower than those achieved thus far (as much as $100/g for purified multi-wall CNTs or $1,000/g for single-wall CNTs in year 2002). The main effort thus far in this program has been the design and implementation of a process tailored specifically for high-throughput screening of alloys for catalyzing the growth of CNTs. The process includes an integral combination of (1) formulation of libraries of catalysts, (2) synthesis of CNTs from decomposition of ethylene on powders of the alloys in a pyrolytic chemical-vapor-decomposition reactor, and (3) scanning- electron-microscope screening of the CNTs thus synthesized to evaluate the catalytic efficiencies of the alloys. Information gained in this process is put into a database and analyzed to identify promising alloy compositions, which are to be subjected to further evaluation in a subsequent round of testing. Some of these alloys have been found to catalyze the formation of carbon nano tubes from ethylene at temperatures as low as 350 to 400 C. In contrast, the temperatures typically required for prior catalysts range from 550 to 750 C.

  20. Catalyst Architecture

    DEFF Research Database (Denmark)

    Kiib, Hans; Marling, Gitte; Hansen, Peter Mandal

    2014-01-01

    How can architecture promote the enriching experiences of the tolerant, the democratic, and the learning city - a city worth living in, worth supporting and worth investing in? Catalyst Architecture comprises architectural projects, which, by virtue of their location, context and their combination...... of programs, have a role in mediating positive social and/or cultural development. In this sense, we talk about architecture as a catalyst for: sustainable adaptation of the city’s infrastructure appropriate renovation of dilapidated urban districts strengthening of social cohesiveness in the city...

  1. AIDS (image)

    Science.gov (United States)

    AIDS (acquired immune deficiency syndrome) is caused by HIV (human immunodeficiency virus), and is a syndrome that ... life-threatening illnesses. There is no cure for AIDS, but treatment with antiviral medication can suppress symptoms. ...

  2. Hearing Aids

    Science.gov (United States)

    ... more in both quiet and noisy situations. Hearing aids help people who have hearing loss from damage ... your doctor. There are different kinds of hearing aids. They differ by size, their placement on or ...

  3. Hearing Aids

    Science.gov (United States)

    ... electrical nerve impulses and send them to the auditory nerve, which connects the inner ear to the ... prefer. Cleaning makes a difference in hearing aid comfort. A perfectly comfortable hearing aid can become pretty ...

  4. Foreign aid

    DEFF Research Database (Denmark)

    Tarp, Finn

    2008-01-01

    Foreign aid has evolved significantly since the Second World War in response to a dramatically changing global political and economic context. This article (a) reviews this process and associated trends in the volume and distribution of foreign aid; (b) reviews the goals, principles and instituti......Foreign aid has evolved significantly since the Second World War in response to a dramatically changing global political and economic context. This article (a) reviews this process and associated trends in the volume and distribution of foreign aid; (b) reviews the goals, principles and...... institutions of the aid system; and (c) discusses whether aid has been effective. While much of the original optimism about the impact of foreign aid needed modification, there is solid evidence that aid has indeed helped further growth and poverty reduction...

  5. Highly active gauze-supported skeletal nickel catalysts

    OpenAIRE

    Fow, Kam Loon; Ganapathi, Murugan; Stassen, Ivo; Fransaer, Jan; Binnemans, Koen; De Vos, Dirk E.

    2013-01-01

    Gauze-supported skeletal nickel catalysts were prepared by electrodeposition of Ni–Zn alloys from an acetamide–DMSO2–NiCl2–ZnCl2 quaternary melt, followed by chemical or electrochemical leaching of zinc from the alloys. The activity and selectivity of the structured RANEY® nickel surpass those of commercial RANEY® nickel in the hydrogenation of acetophenone.

  6. Examining the surfaces in used platinum catalysts

    Directory of Open Access Journals (Sweden)

    Trumić B.

    2009-01-01

    Full Text Available For the purpose of finding more advanced platinum catalyst manufacturing technologies and achieving a higher degree of ammonia oxidation, metallographic characterization has been done on the surface of catalyst gauzes and catalyst gripper gauzes made from platinum and palladium alloys. For the examined samples of gauzes as well as the cross section of the wires, a chemical analysis was provided. The purpose of this paper is the metallographic characterization of examined alloys carried out by way of electronic microscopic scanning, X-rays as well as chemical assays which contributed greatly to a better understanding of the surface deactivation, in other words a better consideration of structural changes occurring on the wire surface.

  7. Electronic-Structure-Based Design of Ordered Alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Andersson, M.P.; Jacobsen, Karsten Wedel; Skriver, Hans Lomholt; Christensen, Claus H.; Nørskov, Jens Kehlet

    2006-01-01

    We describe some recent advances in the methodology of using electronic structure calculations for materials design. The methods have been developed for the design of ordered metallic alloys and metal alloy catalysts, but the considerations we present are relevant for the atomic-scale computational...... discovery of a promising catalytic metal alloy surface with high reactivity and low cost....

  8. Hearing Aids

    Science.gov (United States)

    ... prefer the open-fit hearing aid because their perception of their voice does not sound “plugged up.” ... My voice sounds too loud. The “plugged-up” sensation that causes a hearing aid user’s voice to ...

  9. Brand Aid

    DEFF Research Database (Denmark)

    Richey, Lisa Ann; Ponte, Stefano

    A critical account of the rise of celebrity-driven “compassionate consumption” Cofounded by the rock star Bono in 2006, Product RED exemplifies a new trend in celebrity-driven international aid and development, one explicitly linked to commerce, not philanthropy. Brand Aid offers a deeply informed...

  10. Hearing Aid

    Science.gov (United States)

    ... and Food and Drug Administration Staff FDA permits marketing of new laser-based hearing aid with potential ... feeds Follow FDA on Twitter Follow FDA on Facebook View FDA videos on YouTube View FDA photos ...

  11. Effect of Fe state on electrocatalytic activity of Pd-Fe/C catalyst for oxygen reduction

    International Nuclear Information System (INIS)

    The carbon-supported Pd-Fe catalyst (Pd-Fe/C) is prepared in the H2O/tetrahydrofuran (THF) mixture solvent under the low temperature. The homemade Pd-Fe/C catalyst contains two forms of iron species, alloying and non-alloying Fe. The alloying Fe species is hardly dissolved in 0.5 M H2SO4 solution, while the non-alloying Fe species is easily dissolved in 0.5 M H2SO4 solution. The electrochemical measurements show the electrocatalytic activity of the Pd-Fe/C catalyst with the acid treatment for the oxygen reduction is higher than that of the Pd-Fe/C catalyst without the acid treatment, illustrating that the non-alloying Fe species suppresses the electrocatalytic activity of the Pd-Fe/C catalyst. In contrast, the alloying Fe species promotes the electrocatalytic activity of the Pd-Fe/C catalyst for the oxygen reduction, which is likely attributed to the change of the electron structure of Pd atom and/or bond length of Pd-Pd in the Pd-Fe/C catalyst.

  12. Solvent effects on Pt-Ru/C catalyst for methanol electro-oxidation

    Institute of Scientific and Technical Information of China (English)

    Jinwei Chen; Chunping Jiang; Hui Lu; Lan Feng; Xin Yang; Liangqiong Li; Ruilin Wang

    2009-01-01

    Alloying degree,particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent(s) used in the preparation process can affect the particle size and alloying degree of the object substance,which lead to a great positive impact on its properties. In this work,three types of solvents and their mixtures were used in preparation of the Pt-Ru/C catalysts by chemical reduction of metal precursors with sodium borohydride at room temperature. The structure of the catalysts was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The catalytic activity and stability for methanol electro-oxidation were studied by Cyclic Voltammetry (CV) and Chronoamperometry (CA). Pt-Ru/C catalyst prepared in H_2O or binary solvents of H_2O and isopropanol had large particle size and low alloying degree leading to low catalytic activity and less stability in methanol electro-oxidation. When tetrahydrofuran was added to the above solvent systems,Pt-Ru/C catalyst prepared had smaller particle size and higher alloying degree which resulted in better catalytic activity,lower onset and peak potentials,compared with the above catalysts. Moreover,the catalyst prepared in ternary solvents of isopropanol,water and tetrahydrofuran had the smallest particle size,and the high alloying degree and the dispersion kept unchanged. Therefore,this kind of catalyst showed the highest catalytic activity and good stability for methanol electro-oxidation.

  13. RECYCLING TECHNOLOGY INTO INDUSTRIAL TURNOVER OF BISMUTH AND MOLYBDENUM FROM DEAD CATALYST

    Directory of Open Access Journals (Sweden)

    O. S. Komarov

    2015-05-01

    Full Text Available The technology of separate extraction of bismuth and molybdenum from spent catalyst was presented and information on the effectiveness of its use in a composition of comprehensive modifier in the iron-carbon alloy was given.

  14. Possibility of Wastewater Treatment Using MFC with Ni-Co Catalyst of Fuel Electrode

    Science.gov (United States)

    Włodarczyk, Paweł P.; Włodarczyk, Barbara

    2016-06-01

    One of the problems with microbial fuel cells is a low current density of those energy sources. Nonetheless, it is possible to increase the current density by using the catalyst for fuel electrode (anode) - as long as a low cost catalyst can be found. The possibility of wastewater treatment using the Ni-Co alloy as catalyst for MFC's is presented in this paper. The alloys were obtained with different concentrations of Co (15 and 50% of Co). The increase of current density with Ni-Co catalyst is approximately 0,1 mA/cm2. So, a fundamental possibility wastewater treatment using the Ni-Co alloy as catalyst for microbial fuel cells was presented.

  15. Methanol Electro-Oxidation on Pt-Ru Alloy Nanoparticles Supported on Carbon Nanotubes

    OpenAIRE

    Yangchuan Xing; Liang Li

    2009-01-01

    Carbon nanotubes (CNTs) have been investigated in recent years as a catalyst support for proton exchange membrane fuel cells. Improved catalyst activities were observed and attributed to metal-support interactions. We report a study on the kinetics of methanol electro-oxidation on CNT supported Pt-Ru alloy nanoparticles. Alloy catalysts with different compositions, Pt 53 Ru 47 /CNT, Pt 69 Ru 31 /CNT and Pt 77 Ru 23 /CNT, were prepared and investigated in detail. Experiments were conducted at ...

  16. Types of Hearing Aids

    Science.gov (United States)

    ... Devices Consumer Products Hearing Aids Types of Hearing Aids Share Tweet Linkedin Pin it More sharing options ... some features for hearing aids? What are hearing aids? Hearing aids are sound-amplifying devices designed to ...

  17. Pt -based anode catalysts for direct ethanol fuel cells

    International Nuclear Information System (INIS)

    In this work it is studied the electro-catalytic behavior of pure platinum and platinum-based alloys with Ru, Sn, Ir, and Os supported on carbon to the ethanol electro-oxidation in aims to develop anodic catalysts for direct ethanol fuel cells, additionally, porous electrodes and membrane electrode assemblies were built for proton exchange membrane fuel cells in which the electrodes were tested. Catalysts characterization was made by cyclic voltammetry whereas the fuel cells behavior tests were made by current-potential polarization curves. in general, all alloys show a lower on-set reaction potential and a higher catalytic activity than pure platinum. However, in the high over potential zone, pure platinum has higher catalytic activity than the alloys. In agreement with these results, the alloys studied here could be useful in fuel cells operating on moderated and low current

  18. Foundation Flash Catalyst

    CERN Document Server

    Goralski, Greg

    2010-01-01

    This book offers an introduction to Flash Catalyst for designers with intermediate to advanced skills. It discusses where Catalyst sits within the production process and how it communicates with other programs. It covers all of the features of the Flash Catalyst workspace, teaching you how to create designs from scratch, how to build application designs and add functionality, and how to master the Catalyst/Flex workflow. * Introduces Flash Catalyst * Focuses on production process * Covers the interrelation between Flash Catalyst and Photoshop/Illustrator/Flex/Flash What you'll learn Starting f

  19. Brand Aid

    DEFF Research Database (Denmark)

    Richey, Lisa Ann; Ponte, Stefano

    2011-01-01

    activists, scholars and venture capitalists, discusses the pros and cons of changing the world by ‘voting with your dollars’. Lisa Ann Richey and Stefano Ponte (Professor at Roskilde University and Senior Researcher at DIIS respectively), authors of Brand Aid: Shopping Well to Save the World, highlight how...

  20. Negotiating Aid

    DEFF Research Database (Denmark)

    Whitfield, Lindsay; Fraser, Alastair

    2011-01-01

    This article presents a new analytical approach to the study of aid negotiations. Building on existing approaches but trying to overcome their limitations, it argues that factors outside of individual negotiations (or the `game' in game-theoretic approaches) significantly affect the preferences of...

  1. Design criteria for stable Pt/C fuel cell catalysts

    Directory of Open Access Journals (Sweden)

    Josef C. Meier

    2014-01-01

    Full Text Available Platinum and Pt alloy nanoparticles supported on carbon are the state of the art electrocatalysts in proton exchange membrane fuel cells. To develop a better understanding on how material design can influence the degradation processes on the nanoscale, three specific Pt/C catalysts with different structural characteristics were investigated in depth: a conventional Pt/Vulcan catalyst with a particle size of 3–4 nm and two Pt@HGS catalysts with different particle size, 1–2 nm and 3–4 nm. Specifically, Pt@HGS corresponds to platinum nanoparticles incorporated and confined within the pore structure of the nanostructured carbon support, i.e., hollow graphitic spheres (HGS. All three materials are characterized by the same platinum loading, so that the differences in their performance can be correlated to the structural characteristics of each material. The comparison of the activity and stability behavior of the three catalysts, as obtained from thin film rotating disk electrode measurements and identical location electron microscopy, is also extended to commercial materials and used as a basis for a discussion of general fuel cell catalyst design principles. Namely, the effects of particle size, inter-particle distance, certain support characteristics and thermal treatment on the catalyst performance and in particular the catalyst stability are evaluated. Based on our results, a set of design criteria for more stable and active Pt/C and Pt-alloy/C materials is suggested.

  2. TOPICAL REVIEW: Nanostructured catalysts in fuel cells

    Science.gov (United States)

    Zhong, Chuan-Jian; Luo, Jin; Fang, Bin; Wanjala, Bridgid N.; Njoki, Peter N.; Loukrakpam, Rameshwori; Yin, Jun

    2010-02-01

    One of the most important challenges for the ultimate commercialization of fuel cells is the preparation of active, robust, and low-cost catalysts. This review highlights some findings of our investigations in the last few years in developing advanced approaches to nanostructured catalysts that address this challenge. Emphasis is placed on nanoengineering-based fabrication, processing, and characterization of multimetallic nanoparticles with controllable size (1-10 nm), shape, composition (e.g. MlnM2100-n, M1nM2mM3100-n-m, M1@M2, where M (1 or 2) = Pt, Co, Ni, V, Fe, Cu, Pd, W, Ag, Au etc) and morphology (e.g. alloy, core@shell etc). In addition to an overview of the fundamental issues and the recent progress in fuel cell catalysts, results from evaluations of the electrocatalytic performance of nanoengineered catalysts in fuel cell reactions are discussed. This approach differs from other traditional approaches to the preparation of supported catalysts in the ability to control the particle size, composition, phase, and surface properties. An understanding of how the nanoscale properties of the multimetallic nanoparticles differ from their bulk-scale counterparts, and how the interaction between the nanoparticles and the support materials relates to the size sintering or evolution in the thermal activation process, is also discussed. The fact that the bimetallic gold-platinum nanoparticle system displays a single-phase character different from the miscibility gap known for its bulk-scale counterpart serves as an important indication of the nanoscale manipulation of the structural properties, which is useful for refining the design and preparation of the bimetallic catalysts. The insight gained from probing how nanoparticle-nanoparticle and nanoparticle-substrate interactions relate to the size evolution in the activation process of nanoparticles on planar substrates serves as an important guiding principle in the control of nanoparticle sintering on different

  3. Investigation of surface layer composition of the rhodium-ruthenium catalysts by means of auger spectroscopy

    International Nuclear Information System (INIS)

    The surface layer composition of skeleton catalysts of the rhodium-ruthenium system by means of Auger-electron spectroscopy and electron spectroscopy for the chemical analysis is investigated. It is shown that apart from rhodium, ruthenium aluminium and silicon there is a certain quantity of chemosorbed oxygen accumulated in case of catalysts conservation over a long period of time. The dependence of filling catalysts by chemosorbed oxygen on the alloy composition has been found

  4. Influence of aminosilane surface functionalization of rare earth hydride-forming alloys on palladium treatment by electroless deposition and hydrogen sorption kinetics of composite materials

    International Nuclear Information System (INIS)

    A pre-treatment technique was developed to facilitate electroless deposition of palladium layers on the surface of metal hydride-forming alloys for increasing hydrogen absorption kinetics. The technique involved functionalization of the oxidized surface of the alloys by deposition of assembled layers derived from γ-aminopropyltriethoxysilane. This results in the formation of a surface assembly of adhesive functional groups for the immobilization of palladium as a unique catalyst for hydrogen sorption. The layers of γ-aminopropyltriethoxysilane aided immobilization of Pd nuclei, in the activation procedure of electroless deposition, by increasing the chemical adhesion. Pd electroless deposition on rare-earth metal hydride-forming alloys, without γ-aminopropyltriethoxysilane pre-treatment, facilitated the deposition of Pd agglomerates, whereas the use of γ-aminopropyltriethoxysilane pre-treatment facilitated the deposition of continuous Pd layers on the surface of the alloy resulting in dramatic improvements in hydrogen sorption performances, including faster kinetics of hydrogenation of the non-activated material under mild conditions, compared to that observed for non-activated unmodified starting materials and materials surface modified by Pd electroless deposition without the additional γ-aminopropyltriethoxysilane pre-treatment step. The attractiveness of aminosilane pre-treatment for improvement of hydrogen sorption properties of rare earth-nickel-based AB5 alloys, and the influence of the differences in surface structure between deposited Pd agglomerates and layers was demonstrated

  5. Tactile Aids

    Directory of Open Access Journals (Sweden)

    Mohtaramossadat Homayuni

    1996-04-01

    Full Text Available Tactile aids, which translate sound waves into vibrations that can be felt by the skin, have been used for decades by people with severe/profound hearing loss to enhance speech/language development and improve speechreading.The development of tactile aids dates from the efforts of Goults and his co-workers in the 1920s; Although The power supply was too voluminous and it was difficult to carry specially by children, it was too huge and heavy to be carried outside the laboratories and its application was restricted to the experimental usage. Nowadays great advances have been performed in producing this instrument and its numerous models is available in markets around the world.

  6. Pd Close Coupled Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhong Hua SHI; Mao Chu GONG; Yao Qiang CHEN

    2006-01-01

    A catalyst comprised novel high surface area alumina support was prepared to control emission of automobiles. The results showed that prepared catalyst could satisfy the requirements of a high performance close coupled catalyst for its good catalytic activity at low temperature and good stability at high temperature.

  7. Preparation and Hydrodesulfurization Performance of Ni-B Amorphous Alloy Catalyst Supported by APTS Modified SBA-15%APTS改性SBA-15负载Ni-B非晶态合金催化剂的制备及加氢脱硫性能

    Institute of Scientific and Technical Information of China (English)

    谌伟庆; 黄勇; 石秋杰

    2012-01-01

    SBA-15 was modified by APTS with covalent grafting method,and then Ni-B amorphous alloy catalysts were prepared by using APTS modified SBA-15 and unmodified SBA-15 as supports.The catalytic activities of both catalysts were characterized,and thiophene hydrodesulfurization was selected as probe reaction.The results show that thiophene conversation of Ni-B/SBA-15-APTS is 50.8%,which is higher than the one of Ni-B/SBA-15.The complexation between NH2 and Ni2+ would be benefit for dispersion of Ni-B alloy particles and reduction of Ni2+.According to ICP results,Ni-B/SBA-15-APTS show bigger quantity of Ni in support and higher content of Ni in Ni-B amorphous alloy than Ni-B/SBA-15,resulting in the higher activity.%采用共价接枝法制备APTS改性介孔分子筛SBA-15,将氨基官能团接枝到SBA-15表面.并采用化学还原法制备了Ni-B/SBA-15-APTS非晶态合金催化剂,以噻吩加氢脱硫为探针反应,研究了其催化加氢脱硫性能.结果表明,240℃时,APTS改性SBA-15所负载的Ni-B催化剂噻吩转化率达到50.8%,较未改性SBA-15所负载的催化剂噻吩转化率有显著地提高.由于氨基与Ni2+的配合作用,有助于Ni在催化剂中的分散,因而更容易被还原.ICP结果表明,在相同的制备条件下,相比未改性的SBA-15,APTS改性SBA-15使其催化剂中Ni的负载量增加,并且非晶态合金组成中Ni的含量也增大,B的含量降低,有利于提高催化剂的活性.

  8. Studies on PEM Fuel Cell Noble Metal Catalyst Dissolution

    DEFF Research Database (Denmark)

    Ma, Shuang; Skou, Eivind Morten

    . Membrane Electrode Assembly (MEA) is commonly considered as the heart of cell system [2]. Degradation of the noble metal catalysts in MEAs especially Three-Phase-Boundary (TPB) is a key factor directly influencing fuel cell durability. In this work, electrochemical degradation of Pt and Pt/Ru alloy were...

  9. Bifunctional Anode Catalysts for Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Rossmeisl, Jan; Ferrin, Peter A.; Tritsaris, Georgios A.; Nilekar, Anand U.; Koh, Shirlaine; Bae, Sang Eun; Brankovic, Stanko R.; Strasser, Peter; Mavrikakis, Manos

    2012-06-13

    Using the binding energy of OH* and CO* on close-packed surfaces as reactivity descriptors, we screen bulk and surface alloy catalysts for methanol electro-oxidation activity. Using these two descriptors, we illustrate that a good methanol electro-oxidation catalyst must have three key properties: (1) the ability to activate methanol, (2) the ability to activate water, and (3) the ability to react off surface intermediates (such as CO* and OH*). Based on this analysis, an alloy catalyst made up of Cu and Pt should have a synergistic effect facilitating the activity towards methanol electro-oxidation. Using these two reactivity descriptors, a surface PtCu3 alloy is proposed to have the best catalytic properties of the Pt–Cu model catalysts tested, similar to those of a Pt–Ru bulk alloy. To validate the model, experiments on a Pt(111) surface modified with different amounts of Cu adatoms are performed. Adding Cu to a Pt(111) surface increases the methanol oxidation current by more than a factor of three, supporting our theoretical predictions for improved electrocatalysts.

  10. Neurological Complications of AIDS

    Science.gov (United States)

    ... Diversity Find People About NINDS Neurological Complications of AIDS Fact Sheet Feature Federal domestic HIV/AIDS information ... Where can I get more information? What is AIDS? AIDS (acquired immune deficiency syndrome) is a condition ...

  11. Bifunctional anode catalysts for direct methanol fuel cells

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Ferrin, Peter; Tritsaris, Georgios;

    2012-01-01

    Using the binding energy of OH* and CO* on close-packed surfaces as reactivity descriptors, we screen bulk and surface alloy catalysts for methanol electro-oxidation activity. Using these two descriptors, we illustrate that a good methanol electro-oxidation catalyst must have three key properties......: (1) the ability to activate methanol, (2) the ability to activate water, and (3) the ability to react off surface intermediates (such as CO* and OH*). Based on this analysis, an alloy catalyst made up of Cu and Pt should have a synergistic effect facilitating the activity towards methanol electro....... Adding Cu to a Pt(111) surface increases the methanol oxidation current by more than a factor of three, supporting our theoretical predictions for improved electrocatalysts....

  12. In silico search for novel methane steam reforming catalysts

    Science.gov (United States)

    Xu, Yue; Lausche, Adam C.; Wang, Shengguang; Khan, Tuhin S.; Abild-Pedersen, Frank; Studt, Felix; Nørskov, Jens K.; Bligaard, Thomas

    2013-12-01

    This paper demonstrates a method for screening transition metal and metal alloy catalysts based on their predicted rates and stabilities for a given catalytic reaction. This method involves combining reaction and activation energies (available to the public via a web-based application ‘CatApp’) with a microkinetic modeling technique to predict the rates and selectivities of a prospective material. This paper illustrates this screening technique using the steam reforming of methane to carbon monoxide and hydrogen as a test reaction. While catalysts are already commercially available for this process, the method demonstrated in this paper is very general and could be applied to a wide range of catalytic reactions. Following the steps outlined herein, such an analysis could potentially enable researchers to understand reaction mechanisms on a fundamental level and, on this basis, develop leads for new metal alloy catalysts.

  13. In silico search for novel methane steam reforming catalysts

    International Nuclear Information System (INIS)

    This paper demonstrates a method for screening transition metal and metal alloy catalysts based on their predicted rates and stabilities for a given catalytic reaction. This method involves combining reaction and activation energies (available to the public via a web-based application ‘CatApp’) with a microkinetic modeling technique to predict the rates and selectivities of a prospective material. This paper illustrates this screening technique using the steam reforming of methane to carbon monoxide and hydrogen as a test reaction. While catalysts are already commercially available for this process, the method demonstrated in this paper is very general and could be applied to a wide range of catalytic reactions. Following the steps outlined herein, such an analysis could potentially enable researchers to understand reaction mechanisms on a fundamental level and, on this basis, develop leads for new metal alloy catalysts. (paper)

  14. AIDS Epidemiyolojisi

    OpenAIRE

    SÜNTER, A.T.; PEKŞEN, Y.

    2010-01-01

    AIDS was first defined in the United States in 1981. It spreads to nearly all the countries of the world with a great speed and can infect everbody without any differantiation. The infection results in death and there is no cure or vaccine for it, yet. To data given to World Health Organization until July-1994, it is estimated that there are about 1 million patients and about 22 millions HIV positive persons In the world. Sixty percent of HIV positive persons are men and 40% are women. The di...

  15. Nickel-base alloys combat corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, D.C. [VDM Technologies Corp., Houston, TX (United States); Herda, W. [Krupp-VDM GmbH, Werdohl (Germany)

    1995-06-01

    The modern chemical process industry must increase production efficiency to remain competitive. Manufacturers typically meet this challenge by utilizing higher temperatures and pressures, and more-corrosive catalysts. At the same time, the industry has to solve the technical and commercial problems resulting from rigid environmental regulations. To overcome these obstacles, new alloys having higher levels of corrosion resistance have been developed. These materials are based on increased understanding of the physical metallurgy of nickel-base alloys, especially the role of alloying elements. Results of many studies have led to innovations in nickel-chromium-molybdenum alloys containing both high and low amounts of nickel. Higher molybdenum and chromium contents, together with nitrogen additions, have opened up an entirely new class of alloys having unique properties. In addition, a new chromium-base, fully wrought super stainless steel shows excellent promise in solving many corrosion problems. These newer alloys have the ability to combat uniform corrosion, localized corrosion, and stress-corrosion cracking in the harsh halogenic environment of the chemical process industry. This article briefly lists some of the major highlights and corrosion data on recent nickel-chromium-molybdenum and nickel-molybdenum alloys, and the development of a chromium-base, wrought super-austenitic alloy known as Nicrofer 3033 (Alloy 33). Some comparisons with existing alloys are presented, along with a few commercial applications.

  16. Vapor phase hydrogenation of furfural over nickel mixed metal oxide catalysts derived from layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Sulmonetti, Taylor P.; Pang, Simon H.; Claure, Micaela Taborga; Lee, Sungsik; Cullen, David A.; Agrawal, Pradeep K.; Jones, Christopher W.

    2016-05-01

    The hydrogenation of furfural is investigated over various reduced nickel mixed metal oxides derived from layered double hydroxides (LDHs) containing Ni-Mg-Al and Ni-Co-Al. Upon reduction, relatively large Ni(0) domains develop in the Ni-Mg-Al catalysts, whereas in the Ni-Co-Al catalysts smaller metal particles of Ni(0) and Co(0), potentially as alloys, are formed, as evidenced by XAS, XPS, STEM and EELS. All the reduced Ni catalysts display similar selectivities towards major hydrogenation products (furfuryl alcohol and tetrahydrofurfuryl alcohol), though the side products varied with the catalyst composition. The 1.1Ni-0.8Co-Al catalyst showed the greatest activity per titrated site when compared to the other catalysts, with promising activity compared to related catalysts in the literature. The use of base metal catalysts for hydrogenation of furanic compounds may be a promising alternative to the well-studied precious metal catalysts for making biomass-derived chemicals if catalyst selectivity can be improved in future work by alloying or tuning metal-oxide support interactions.

  17. Development of highly active and stable hybrid cathode catalyst for PEMFCs

    Science.gov (United States)

    Jung, Won Suk

    Polymer electrolyte membrane fuel cells (PEMFCs) are attractive power sources of the future for a variety of applications including portable electronics, stationary power, and automobile application. However, sluggish cathode kinetics, high Pt cost, and durability issues inhibit the commercialization of PEMFCs. To overcome these drawbacks, research has been focused on alloying Pt with transition metals since alloy catalysts show significantly improved catalytic properties like high activity, selectivity, and durability. However, Pt-alloy catalysts synthesized using the conventional impregnation method exhibit uneven particle size and poor particle distribution resulting in poor performance and/or durability in PEMFCs. In this dissertation, a novel catalyst synthesis methodology is developed and compared with catalysts prepared using impregnation method and commercial catalysts. Two approaches are investigated for the catalyst development. The catalyst durability was studied under U. S. DRIVE Fuel Cell Tech Team suggested protocols. In the first approach, the carbon composite catalyst (CCC) having active sites for oxygen reduction reaction (ORR) is employed as a support for the synthesis of Pt/CCC catalyst. The structural and electrochemical properties of Pt/CCC catalyst are investigated using high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, while RDE and fuel cell testing are carried out to study the electrochemical properties. The synergistic effect of CCC and Pt is confirmed by the observed high activity towards ORR for the Pt/CCC catalyst. The second approach is the synthesis of Co-doped hybrid cathode catalysts (Co-doped Pt/CCC) by diffusing the Co metal present within the CCC support into the Pt nanoparticles during heat-treatment. The optimized Co-doped Pt/CCC catalyst performed better than the commercial catalysts and the catalyst prepared using the impregnation method in PEMFCs and showed high

  18. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  19. Towards the Rational Design of Nanoparticle Catalysts

    Science.gov (United States)

    Dash, Priyabrat

    stabilization in BMIMPF6 IL is described, and have shown that nanoparticle stability and catalytic activity of nanoparticles is dependent on the overall stability of the nanoparticles towards aggregation (manuscript submitted). The second major project is focused on synthesizing structurally well-defined supported catalysts by incorporating the nanoparticle precursors (both alloy and core shell) into oxide frameworks (TiO2 and Al2O 3), and examining their structure-property relationships and catalytic activity. a full article has been published on this project (Journal of Physical Chemistry C, 2009, 113, 12719) in which a route to rationally design supported catalysts from structured nanoparticle precursors with precise control over size, composition, and internal structure of the nanoparticles has been shown. In a continuation of this methodology for the synthesis of heterogeneous catalysts, efforts were carried out to apply the same methodology in imidazolium-based ILs as a one-pot media for the synthesis of supported-nanoparticle heterogeneous catalysts via the trapping of pre-synthesized nanoparticles into porous inorganic oxide materials. Nanoparticle catalysts in highly porous titania supports were synthesized using this methodology (manuscript to be submitted).

  20. Carbon-resistant Ni-Zr0.92Y0.08O2-δ supported solid oxide fuel cells using Ni-Cu-Fe alloy cermet as on-cell reforming catalyst and mixed methane-steam as fuel

    Science.gov (United States)

    Hua, Bin; Li, Meng; Luo, Jing-li; Pu, Jian; Chi, Bo; Li, Jian

    2016-01-01

    Two types of anode-supported cell are fabricated by tape casting, screen printing and sintering processes. The first one is a conventional anode supported cell (ASC); and the other, namely CASC, contains an extra layer of Ni-Cu/Ni-Fe alloys-BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (NCF-BZCYYb) cermet catalyst on the surface of the anode-support. Using CH4-3 mol. % H2O as the fuel, the initial performance of the CASC is moderately improved, compared with that of the ASC; the power density of the CASC and ASC at 500 mA cm-2 and 800 °C remain stable on the level of 470 mW cm-2 for approximately 11 and 0.8 h, respectively, before cell disintegration caused by carbon formation. The performances of the CASC in the fuel of CH4-33.3 mol. % H2O are significantly increased above the level of the ASC, demonstrating an initial peak power density ranging from 280 to 1638 mW cm-2 at temperatures between 600 and 800 °C and a stable power density of 485 mW cm-2 at 500 mA cm-2 and 800 °C for 48 h. Carbon deposition in the anode region of the tested CASC cell is not detected, as the NCF-BZCYYb is a more active catalyst than the Ni-Zr0.92Y0.08O2-δ (YSZ) anode-support for CH4 steam reforming.

  1. Design of Pd-Based Bimetallic Catalysts for ORR: A DFT Calculation Study

    Directory of Open Access Journals (Sweden)

    Lihui Ou

    2015-01-01

    Full Text Available Developing Pd-lean catalysts for oxygen reduction reaction (ORR is the key for large-scale application of proton exchange membrane fuel cells (PEMFCs. In the present paper, we have proposed a multiple-descriptor strategy for designing efficient and durable ORR Pd-based alloy catalysts. We demonstrated that an ideal Pd-based bimetallic alloy catalyst for ORR should possess simultaneously negative alloy formation energy, negative surface segregation energy of Pd, and a lower oxygen binding ability than pure Pt. By performing detailed DFT calculations on the thermodynamics, surface chemistry and electronic properties of Pd-M alloys, Pd-V, Pd-Fe, Pd-Zn, Pd-Nb, and Pd-Ta, are identified theoretically to have stable Pd segregated surface and improved ORR activity. Factors affecting these properties are analyzed. The alloy formation energy of Pd with transition metals M can be mainly determined by their electron interaction. This may be the origin of the negative alloy formation energy for Pd-M alloys. The surface segregation energy of Pd is primarily determined by the surface energy and the atomic radius of M. The metals M which have smaller atomic radius and higher surface energy would tend to favor the surface segregation of Pd in corresponding Pd-M alloys.

  2. Macroeconomic Issues in Foreign Aid

    DEFF Research Database (Denmark)

    Hjertholm, Peter; Laursen, Jytte; White, Howard

    foreign aid, macroeconomics of aid, gap models, aid fungibility, fiscal response models, foreign debt,......foreign aid, macroeconomics of aid, gap models, aid fungibility, fiscal response models, foreign debt,...

  3. Synergetic effects leading to coke-resistant NiCo bimetallic catalysts for dry reforming of methane

    KAUST Repository

    Li, Lidong

    2015-01-08

    A new dry reforming of methane catalyst comprised of NiCo bimetallic nanoparticles and a Mgx(Al)O support that exhibits high coke resistance and long-term on-stream stability is reported. The structural characterization by XRD, TEM, temperature-programmed reduction, and BET analysis demonstrates that the excellent performance of this catalyst is ascribed to the synergy of various parameters, including metal-nanoparticle size, metal-support interaction, catalyst structure, ensemble size, and alloy effects.

  4. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  5. HIV and AIDS

    Science.gov (United States)

    ... Got Homework? Here's Help White House Lunch Recipes HIV and AIDS KidsHealth > For Kids > HIV and AIDS ... actually the virus that causes the disease AIDS. HIV Hurts the Immune System People who are HIV ...

  6. HIV-AIDS Connection

    Science.gov (United States)

    ... Content Marketing Share this: Main Content Area The HIV-AIDS Connection AIDS was first recognized in 1981 ... cancers. Why is there overwhelming scientific consensus that HIV causes AIDS? Before HIV infection became widespread in ...

  7. Heart attack first aid

    Science.gov (United States)

    First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... A heart attack occurs when the blood flow that carries oxygen to the heart is blocked. The heart muscle becomes ...

  8. AIDS.gov

    Science.gov (United States)

    ... Hospitalization and Palliative Care Friends & Family Dating and Marriage Family Planning Mixed-Status Couples Discrimination Legal Issues ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS ...

  9. Breathing difficulties - first aid

    Science.gov (United States)

    Difficulty breathing - first aid; Dyspnea - first aid; Shortness of breath - first aid ... Breathing difficulty is almost always a medical emergency. An exception is feeling slightly winded from normal activity, ...

  10. Heart attack first aid

    Science.gov (United States)

    First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... A heart attack occurs when the blood flow that carries oxygen to the heart is blocked. The heart muscle ...

  11. Nosebleed, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Nosebleed, First Aid A A A First Aid for Nosebleed: View ... of the nose, causing bleeding into the throat. First Aid Guide The following self-care measures are recommended: ...

  12. Unconsciousness - first aid

    Science.gov (United States)

    Loss of consciousness - first aid; Coma - first aid; Mental status change; Altered mental status ... has a change in mental status, follow these first aid steps: Call or tell someone to call 911 . ...

  13. Splinter, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Splinter, First Aid A A A First Aid for Splinter: View ... wet, it makes the area prone to infection. First Aid Guide Self-care measures to remove a splinter ...

  14. Heterogeneous hydrogenation catalysts

    International Nuclear Information System (INIS)

    The main types of heterogeneous catalysts used for hydrogenation, the methods for their preparation, and the structure and chemistry of their surfaces are considered, as well as the catalytic activity and the mechanism of action in the hydrogenation of unsaturated and aromatic compounds, of CO, and of carbonyl compounds and in the hydrorefining of fuels. Chief attention is paid to supported Ni catalysts, to the methods for their preparation and physicochemical studies, and to the development of novel catalytic systems through modification. A novel type of catalyst for hydrogenation, viz. metal carbides, is described. Some aspects of the mechanochemical treatment of hydrogenation catalysts, including in situ methods, are discussed. Sulfide catalysts for hydrotreating are also discussed in detail. The bibliography includes 340 references.

  15. Effects of Cu over Pd based catalysts supported on silica or niobia

    Directory of Open Access Journals (Sweden)

    Roma M.N.S.C.

    2000-01-01

    Full Text Available Palladium and palladium-copper catalysts supported on silica and niobia were characterized by H2 chemisorption and H2-O2 titration. Systems over silica were also analyzed by transmission electron microscopy and EXAFS. The metallic dispersion decreased from 20% to 7% when the content of Pd was increased from 0.5wt.-% to 3wt.-% in monometallic catalysts. The addition of 3 wt.-% Cu to obtain Pd-Cu catalysts caused a remarkable capacity loss of hydrogen chemisorption. TPR analysis suggested an interaction between the two metals and EXAFS characterization of the catalyst supported on silica confirmed the formation of Pd-Cu alloy. Pd/Nb2O5 catalysts showed turnover numbers higher than those obtained with the Pd/SiO2 systems in the cyclohexane dehydrogenation. However, the bimetallic catalysts showed very low turnover numbers.

  16. Manufacture of Raney Ni catalyst with metastable Ni2Al3 by high—energy milling

    Institute of Scientific and Technical Information of China (English)

    滕荣厚; 马如璋; 等

    1999-01-01

    The Ni-Al alloy containing Cr,Fe additives were prepared as Raney Ni Catalyst by high energy milling.The size and surface state of Ni-Al alloy powder were studied by particle size analyzer and sanning electron microscopy.the Structure was analyzed by XRD and Moessbauer methods.The results showed that after a high-energy milling(HEM).the Ni-Al alloy transforms to a nano-scale NiAl structure with rich Al.By annealing the alloy,a metastable Ni2Al3 phase can be obtained.

  17. Manufacture of Raney Ni catalyst with metastable Ni2Al3 by high-energy milling

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Ni-Al alloy containing Cr, Fe additives were prepared as Raney Ni catalyst by high energy milling. The size and surface state of Ni-Al alloy powder were studied by particle size analyzer and sanning electron microscopy, the structure was analyzed by XRD and Mossbauer methods. The results showed that after a high-energy milling (HEM), the Ni-Al alloy transforms to a nano-scale NiAl structure with rich Al. Byannealing the alloy, a metastable Ni2Al3 phase can be obtained.

  18. Catalysts, methods of making catalysts, and methods of use

    KAUST Repository

    Renard, Laetitia

    2014-03-06

    Embodiments of the present disclosure provide for catalysts, methods of making catalysts, methods of using catalysts, and the like. In an embodiment, the method of making the catalysts can be performed in a single step with a metal nanoparticle precursor and a metal oxide precursor, where a separate stabilizing agent is not needed.

  19. Titania Supported Pt and Pt/Pd Nano-particle Catalysts for the Oxidation of Sulfur Dioxide

    DEFF Research Database (Denmark)

    Koutsopoulos, Sotiris; Johannessen, Tue; Eriksen, Kim Michael;

    2006-01-01

    Several types of titania (anatase) were used as supports for pure platinum and Pt–Pd bimetallic alloy catalysts. The preparation methods, normal wet impregnation technique and flame aerosol synthesis, obtained metal loadings of 2% by weight. The prepared catalysts were tested for SO2 oxidation...... activity at atmospheric pressure in the temperature range 250–600 °C. The SO2 to SO3 conversion efficiency of the Pt–Pd alloy was significantly higher than that of the individual metals. The effects of the preparation method and the titania type used on the properties and activity of the resulting catalyst...

  20. Catalyst in Basic Oleochemicals

    Directory of Open Access Journals (Sweden)

    Eva Suyenty

    2007-10-01

    Full Text Available Currently Indonesia is the world largest palm oil producer with production volume reaching 16 million tones per annum. The high crude oil and ethylene prices in the last 3 – 4 years contribute to the healthy demand growth for basic oleochemicals: fatty acids and fatty alcohols. Oleochemicals are starting to replace crude oil derived products in various applications. As widely practiced in petrochemical industry, catalyst plays a very important role in the production of basic oleochemicals. Catalytic reactions are abound in the production of oleochemicals: Nickel based catalysts are used in the hydrogenation of unsaturated fatty acids; sodium methylate catalyst in the transesterification of triglycerides; sulfonic based polystyrene resin catalyst in esterification of fatty acids; and copper chromite/copper zinc catalyst in the high pressure hydrogenation of methyl esters or fatty acids to produce fatty alcohols. To maintain long catalyst life, it is crucial to ensure the absence of catalyst poisons and inhibitors in the feed. The preparation methods of nickel and copper chromite catalysts are as follows: precipitation, filtration, drying, and calcinations. Sodium methylate is derived from direct reaction of sodium metal and methanol under inert gas. The sulfonic based polystyrene resin is derived from sulfonation of polystyrene crosslinked with di-vinyl-benzene. © 2007 BCREC UNDIP. All rights reserved.[Presented at Symposium and Congress of MKICS 2007, 18-19 April 2007, Semarang, Indonesia][How to Cite: E. Suyenty, H. Sentosa, M. Agustine, S. Anwar, A. Lie, E. Sutanto. (2007. Catalyst in Basic Oleochemicals. Bulletin of Chemical Reaction Engineering and Catalysis, 2 (2-3: 22-31.  doi:10.9767/bcrec.2.2-3.6.22-31][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.2.2-3.6.22-31 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/6

  1. Study of spent hydrorefining catalysts

    International Nuclear Information System (INIS)

    Aluminonickelmolybdenum catalysts for diesel fuel hydrorefining have been studied by DTA, XSPS, and diffuse reflection spectroscopy. Chemical and phase states of molybdenum compounds in samples of fresh catalyst, regenerated one after one year operation, and clogged with coke catalyst after five year operation, are determined. Chemical reactions and crystal-phase transformations of the molybdenum compounds during catalyst deactivation and regeneration are discussed

  2. Hydrogen adsorption on skeletal rhodium-tantalum electrodes-catalysts

    International Nuclear Information System (INIS)

    Skeleton rhodium-tantalic catalyst electrodes with a tantalum mass percentage of 0 to 100 have been obtained by the methodology of Crupp and others. The hydrogen adsorption is studied through the method of removing the galvano-static and potentiodynamic curves of charging in sulfuric acid and potassium hydroxide. It has been discovered that the maximum adsorption ability relatively to the hydrogen can be observed in an alloy with a 5% tantalum contents. The energetic characteristics of the alloys are higher in alkali than in acid

  3. Method for forming gold-containing catalyst with porous structure

    Energy Technology Data Exchange (ETDEWEB)

    Biener, Juergen; Hamza, Alex V; Baeumer, Marcus; Schulz, Christian; Jurgens, Birte; Biener, Monika M.

    2014-07-22

    A method for forming a gold-containing catalyst with porous structure according to one embodiment of the present invention includes producing a starting alloy by melting together of gold and at least one less noble metal that is selected from the group consisting of silver, copper, rhodium, palladium, and platinum; and a dealloying step comprising at least partial removal of the less noble metal by dissolving the at least one less noble metal out of the starting alloy. Additional methods and products thereof are also presented.

  4. Evaluating the role of Lead In A Novel Ternary Catalysts For DMFCs

    CERN Document Server

    Halder, Aditi; Trahan, Matthew; Mukerjee, Sanjeev

    2012-01-01

    The current density at lower potential is highly desirable in fuel cell technology and crucial center point for designing a new catalyst. By alloying platinum with various other metals, the improvisation of the fuel cell catalyst has achieved a lot of attention and interests. In this article, a novel porous ternary alloy PtPb@Ru as anode catalysts for direct methanol fuel cell had been synthesized by micro-emulsion technique. The catalysts had been characterized by various spectroscopic and microscopic techniques. The activity and durability of the catalysts had been tested by running cyclic voltammetry in 0.1 M HClO4 and 1M Methanol. To explain the many fold increase in current density of the PtPb@Ru catalysts in comparison to the commercial available PtRu catalysts, in situ X-ray absorption spectroscopy (XAS) measurements, at the PtL3 edge (XANES and EXAFS) were carried out on the PtPb@Ru catalysts in an electrochemical cell. The down-shift in the d-band center of platinum observed in the XAS study, might b...

  5. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    SOUMEN SAHA; SONALIKA VAIDYA; KANDALAM V RAMANUJACHARY; SAMUEL E LOFLAND; ASHOK K GANGULI

    2016-04-01

    Cu–Fe–Ni ternary alloys (size ∼55–80 nm) with varying compositions viz. CuFeNi (A1), CuFe2Ni (A2) and CuFeNi2 (A3) were successfully synthesized using microemulsion. It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an appropriate microemulsion system. High electrocatalytic activity towards HER in alkaline medium was achieved by the formation of alloys of metals with low and high binding energies. A high value of current density (228 mA cm$^2$) at an overpotential of 545 mV was obtained for CuFeNi (A1), which is significantly high as compared to the previously reported Ni$_{59}$Cu$_{41}$ alloy catalyst.

  6. Confinement dependence of electro-catalysts for hydrogen evolution from water splitting

    Directory of Open Access Journals (Sweden)

    Mikaela Lindgren

    2014-02-01

    Full Text Available Density functional theory is utilized to articulate a particular generic deconstruction of the electrode/electro-catalyst assembly for the cathode process during water splitting. A computational model was designed to determine how alloying elements control the fraction of H2 released during zirconium oxidation by water relative to the amount of hydrogen picked up by the corroding alloy. This model is utilized to determine the efficiencies of transition metals decorated with hydroxide interfaces in facilitating the electro-catalytic hydrogen evolution reaction. A computational strategy is developed to select an electro-catalyst for hydrogen evolution (HE, where the choice of a transition metal catalyst is guided by the confining environment. The latter may be recast into a nominal pressure experienced by the evolving H2 molecule. We arrived at a novel perspective on the uniqueness of oxide supported atomic Pt as a HE catalyst under ambient conditions.

  7. Types of Foreign Aid

    DEFF Research Database (Denmark)

    Bjørnskov, Christian

    Foreign aid is given for many purposes and different intentions, yet most studies treat aid flows as a unitary concept. This paper uses factor analysis to separate aid flows into different types. The main types can be interpreted as aid for economic purposes, social purposes, and reconstruction; a...... residual category captures remaining purposes. Estimating the growth effects of separable types of aid suggests that most aid has no effects while reconstruction aid has direct positive effects. Although this type only applies in special circumstances, it has become more prevalent in more recent years....

  8. Structure and Stability of Pt-Y Alloy Particles for Oxygen Reduction Studied by Electron Microscopy

    DEFF Research Database (Denmark)

    Deiana, Davide; Wagner, Jakob Birkedal; Hansen, Thomas Willum

    2015-01-01

    Platinum-yttrium alloy nanoparticles show both a high activity and stability for the oxygen reduction reaction. The catalysts were prepared by magnetron sputter aggregation and mass filtration providing a model catalyst system with a narrow size distribution. The structure and stability of nanost...... catalyst after reaction and after aging tests shows the development of a core-shell type structure after being exposed to reaction conditions....

  9. Catalyst for microelectromechanical systems microreactors

    Energy Technology Data Exchange (ETDEWEB)

    Morse, Jeffrey D. (Martinez, CA); Sopchak, David A. (Livermore, CA); Upadhye, Ravindra S. (Pleasanton, CA); Reynolds, John G. (San Ramon, CA); Satcher, Joseph H. (Patterson, CA); Gash, Alex E. (Brentwood, CA)

    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.

  10. Catalyst for microelectromechanical systems microreactors

    Science.gov (United States)

    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.

  11. Mesoporous molecular sieve catalysts

    DEFF Research Database (Denmark)

    Højholt, Karen Thrane

    the micropores. Furthermore, preliminary work was done using mesoporous ZSM-5 zeolites as support material for anchoring molecular CoMo6 species for the application as potential bi-functional catalyst in simultaneous hydrodesulfurisation (HDS) and hydrocracking. HDS activity tests revealed that the...... of different catalytic applications. Primarily the zeolites were modified regarding the porosity and the introduction of metals to the framework. The obtained materials were used as solid acid catalysts, as an inert matrix for stabilising metal nanoparticles and as an anchoring material for molecular...... only be used as solid acid catalysts but can also be used as a size-selective matrix. It was shown that it is possible to encapsulate 1-2 nm sized gold nanoparticles by silicalite-1 or ZSM-5 zeolite crystals thereby forming a sintering-stable and substrate size-selective oxidation catalyst. After...

  12. Epoxidation catalyst and process

    Science.gov (United States)

    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.

  13. Thinking about Aid Predictability

    OpenAIRE

    Andrews, Matthew; Wilhelm, Vera

    2008-01-01

    Researchers are giving more attention to aid predictability. In part, this is because of increases in the number of aid agencies and aid dollars and the growing complexity of the aid community. A growing body of research is examining key questions: Is aid unpredictable? What causes unpredictability? What can be done about it? This note draws from a selection of recent literature to bring s...

  14. Heterogeneous chromium catalysts

    OpenAIRE

    2005-01-01

    The present invention relates to a heterogeneous chromium catalyst system for the polymerisation of ethylene and/or alpha olefins prepared by the steps of: (a) providing a silica-containing support, (b) treating the silica-containing support with a chromium compound to form a chromium-based silica-containing support, (c) activating the chromium-based silica-containing support, (d) chemically reducing the activated chromium-based silica-containing support to produce a precursor catalyst, (e) r...

  15. Aftermarket catalyst durability evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bruetsch, R.I.; Cheng, J.P.; Hellman, K.H.

    1986-01-01

    Suppliers have introduced replacement aftermarket catalytic converters which are characterized by design differences from the original equipment converters in the direction of lower costs. The objective of the work reported here was to test a group of nine aftermarket catalysts from three manufacturers for 25,000 miles. Mileage was accumulated on three routes in Maryland and West Virginia characterized by varying degrees of tire wear. All catalysts were dynamometer tested on the same vehicle at the same laboratory.

  16. Studies of the electronic structure of simple metals and their alloys with the aid of compton scattering and positron annihilation using lithium, magnesium, lithium-magnesium and aluminium-zinc as examples

    International Nuclear Information System (INIS)

    The results show that the positron annihilation is an appropriate method for receiving information on the Fermi levels of simple metals. Concerning the global electronic structure of alloys, however, its applicability is limited, particularly in the case of Al-Zn, whereas the local electronic structure can be determined. The Compton profiles were calculated for the metals and compared with experimental results. The influence of the potential Fourier components, of the orthogonalization properties and of interactions on the electronic structure was studied. A first insight into the electronic structure of Zn-Al was gained. (author)

  17. Electrical Resistance Alloys and Low-Expansion Alloys

    DEFF Research Database (Denmark)

    Kjer, Torben

    1996-01-01

    The article gives an overview of electrical resistance alloys and alloys with low thermal expansion. The electrical resistance alloys comprise resistance alloys, heating alloys and thermostat alloys. The low expansion alloys comprise alloys with very low expansion coefficients, alloys with very low...... thermoelastic coefficients and age hardenable low expansion alloys....

  18. How to Get Hearing Aids

    Science.gov (United States)

    ... Consumer Products Hearing Aids How to get Hearing Aids Share Tweet Linkedin Pin it More sharing options ... my hearing aids? How do I get hearing aids? To get hearing aids, you should first have ...

  19. Characterization and Catalytic Properties of a Rapidly Quenched Ni-RE-P-AL Catalyst

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A Ni-RE-P-AL catalyst prepared by alkaline extraction of a rapidly quenched Ni-RE-P-AL alloy was characterized by means of ICP,BET,XRD,ZPS and TEM.The results show that the rapidly quenched Ni-RE-P-AL alloy contained less crystalline AL3Ni than AL-Ni alloy.After alkaline extraction,most of Al in the Ni-RE-P-AL alloy was leached out and the resulted Ni-RE-P-AL catalyst presented a spone structure similar to Raney Ni.Although Crystalline Ni is the major phase in the Ni-RE-P-AL catalyst and Raney Ni,amorphous Ni-P phase has been detected in the Ni-RE-P-AL catalyst.Studies on catalytic hydrogenation of toluene,phenyl ethylene,acetylene benzene,nitrobenzene,cyclohexanone and adiponitrile in liquid phase showed that the activity and selectivity of this Ni-RE-P-AL catalyst are superior to those of Raney Ni,especially at low temperatures.The amorphous phase is considered to be responsible for its superior catalytic properties.

  20. An Exploration of Geometric and Electronic Effects in Metal Nanoparticle Catalysts

    Science.gov (United States)

    Childers, David

    The goal of this thesis is to investigate the influence geometric and electronic effects on metal nanoparticle catalysis. There are three main methods which alter a catalyst's properties: changing support material, changing nanoparticle size and alloying a second metal. This work will focus on the latter two methods using Pt-group metals and alloys. Platinum and palladium were chosen as the active metals due to a large amount of industry significance and prior literature to draw upon. Neopentane conversion and propane dehydrogenation were the two probe reactions used to evaluate these catalysts mainly due to their relative simplicity and ease of operation on a laboratory scale. The effect of particle size was studied with Pt and Pd monometallic catalysts using neopentane hydrogenolysis/isomerization as the probe reaction. Particle size studies have been done previously using this reaction so there is literature data to compare this study's results. This data will also be used as comparison for the bimetallic studies conducted later so that particle size effects can be accounted for when attempting to determine the effect of alloying a second metal. Bimetallic catalysts have several different possible structures depending on a number of factors from the identity of the two metals to the synthesis procedure. Homogeneous, core-shell and intermetallic alloys are the three structures evaluated in this work. Determining the surface composition of a homogeneous alloy can be difficult especially if both metals adsorb CO. PtPd homogeneous alloys were used to evaluate the ability of EXAFS to give information about surface composition using CO adsorption. These catalysts were also tested using neopentane conversion to evaluate changes in catalytic performance. Core-shell catalysts can also exhibit unique properties although it is not clear whether the identity of the core metal is relevant or if surface changes are most important to changing catalytic behavior. PdAu catalysts

  1. In silico search for novel methane steam reforming catalysts

    OpenAIRE

    Xu, Yue; Lausche, Adam C; Wang, Shengguang; Khan, Tuhin Suvra; Abild-Pedersen, Frank; Studt, Felix; Nørskov, Jens K.; Bligaard, Thomas

    2013-01-01

    This paper demonstrates a method for screening transition metal and metal alloy catalysts based on their predicted rates and stabilities for a given catalytic reaction. This method involves combining reaction and activation energies (available to the public via a web-based application ‘CatApp’) with a microkinetic modeling technique to predict the rates and selectivities of a prospective material. This paper illustrates this screening technique using the steam reforming of methane to carbon m...

  2. Adsorbate induced surface alloy formation investigated by near ambient pressure X-ray photoelectron spectroscopy

    DEFF Research Database (Denmark)

    Nierhoff, Anders Ulrik Fregerslev; Conradsen, Christian Nagstrup; McCarthy, David Norman;

    2014-01-01

    Formation of meta-stable surface-alloys can be used as a way to tune the binding strength of reaction intermediates and could therefore be used as improved catalyst materials for heterogeneous catalysis. Understanding the role of adsorbates on such alloy surfaces can provide new insights for...

  3. PdZn catalysts prepared by washcoating microstructured reactors

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, P.; Schubert, K. [Forschungszentrum Karlsruhe GmbH, Institute for Micro Process Engineering, POB 3640, 76021 Karlsruhe (Germany); Liauw, M.A.; Emig, G. [University Erlangen-Nurnberg, LTC1, Egerlandstrasse 3, 91058 Erlangen (Germany)

    2004-08-30

    Methanol steam reforming is an option for dynamic hydrogen generation in automotive fuel cell systems. Microstructured reactors with small channels (100{mu}mx100{mu}m) are being studied. A washcoating procedure applying dispersed ZnO nanoparticles to the microchannel walls was adapted to the PdZn catalyst system. The catalyst layer showed no significant differences during X-ray diffraction and temperature-programmed oxidation and reduction experiments for examination of oxidation state and alloy formation compared with other PdZn systems reported in the literature. Chemisorption with different adsorbates and X-ray backscattering were used for gathering detailed information on PdZn dispersion, diameter and shape with respect to the preparation parameters. Catalytic experiments yielded a relationship between the catalyst properties and the catalytic activity, degradation and secondary reactions.

  4. Magnetic and dendritic catalysts.

    Science.gov (United States)

    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

  5. Catalyst design for enhanced sustainability through fundamental surface chemistry.

    Science.gov (United States)

    Personick, Michelle L; Montemore, Matthew M; Kaxiras, Efthimios; Madix, Robert J; Biener, Juergen; Friend, Cynthia M

    2016-02-28

    Decreasing energy consumption in the production of platform chemicals is necessary to improve the sustainability of the chemical industry, which is the largest consumer of delivered energy. The majority of industrial chemical transformations rely on catalysts, and therefore designing new materials that catalyse the production of important chemicals via more selective and energy-efficient processes is a promising pathway to reducing energy use by the chemical industry. Efficiently designing new catalysts benefits from an integrated approach involving fundamental experimental studies and theoretical modelling in addition to evaluation of materials under working catalytic conditions. In this review, we outline this approach in the context of a particular catalyst-nanoporous gold (npAu)-which is an unsupported, dilute AgAu alloy catalyst that is highly active for the selective oxidative transformation of alcohols. Fundamental surface science studies on Au single crystals and AgAu thin-film alloys in combination with theoretical modelling were used to identify the principles which define the reactivity of npAu and subsequently enabled prediction of new reactive pathways on this material. Specifically, weak van der Waals interactions are key to the selectivity of Au materials, including npAu. We also briefly describe other systems in which this integrated approach was applied. PMID:26755756

  6. Controllable galvanic synthesis of triangular Ag-Pd alloy nanoframes for efficient electrocatalytic methanol oxidation.

    Science.gov (United States)

    Xu, Lin; Luo, Zhimin; Fan, Zhanxi; Yu, Sijia; Chen, Junze; Liao, Yusen; Xue, Can

    2015-06-01

    Triangular Ag-Pd alloy nanoframes were successfully synthesized through galvanic replacement by using Ag nanoprisms as sacrificial templates. The ridge thickness of the Ag-Pd alloy nanoframes could be readily tuned by adjusting the amount of the Pd source during the reaction. These obtained triangular Ag-Pd alloy nanoframes exhibit superior electrocatalytic activity for the methanol oxidation reaction as compared with the commercial Pd/C catalyst due to the alloyed Ag-Pd composition as well as the hollow-framed structures. This work would be highly impactful in the rational design of future bimetallic alloy nanostructures with high catalytic activity for fuel cell systems. PMID:25925988

  7. Hydrogen absorption induced metal deposition on palladium and palladium-alloy particles

    Science.gov (United States)

    Wang, Jia X.; Adzic, Radoslav R.

    2009-03-24

    The present invention relates to methods for producing metal-coated palladium or palladium-alloy particles. The method includes contacting hydrogen-absorbed palladium or palladium-alloy particles with one or more metal salts to produce a sub-monoatomic or monoatomic metal- or metal-alloy coating on the surface of the hydrogen-absorbed palladium or palladium-alloy particles. The invention also relates to methods for producing catalysts and methods for producing electrical energy using the metal-coated palladium or palladium-alloy particles of the present invention.

  8. Electrochemical dissolution of steel as a typical catalyst for electro-Fenton oxidation

    OpenAIRE

    Kočanová, Veronika; Dušek, Libor

    2016-01-01

    Abstract Although traditional Fenton reaction is known for a long time, it is still a perspective method for removal of pollution from wastewater. Applications of electro-Fenton oxidation are commonly used in wastewater treatment. These methods are classified into groups—electrochemical advanced oxidation processes. Typical catalysts for these technologies are Fe2+ ions. Comparison between two material types of steel was investigated in this paper. Alloy steel Cr–Ni and non-alloy steel were u...

  9. Aid and growth regressions

    DEFF Research Database (Denmark)

    Hansen, Henrik; Tarp, Finn

    2001-01-01

    This paper examines the relationship between foreign aid and growth in real GDP per capita as it emerges from simple augmentations of popular cross country growth specifications. It is shown that aid in all likelihood increases the growth rate, and this result is not conditional on ‘good’ policy....... There are, however, decreasing returns to aid, and the estimated effectiveness of aid is highly sensitive to the choice of estimator and the set of control variables. When investment and human capital are controlled for, no positive effect of aid is found. Yet, aid continues to impact on growth via...

  10. Synthesis of CuNi/C and CuNi/γ-Al2O3 Catalysts for the Reverse Water Gas Shift Reaction

    Directory of Open Access Journals (Sweden)

    Maxime Lortie

    2015-01-01

    Full Text Available A new polyol synthesis method is described in which CuNi nanoparticles of different Cu/Ni atomic ratios were supported on both carbon and gamma-alumina and compared with Pt catalysts using the reverse water gas shift, RWGS, reaction. All catalysts were highly selective for CO formation. The concentration of CH4 was less than the detection limit. Cu was the most abundant metal on the CuNi alloy surfaces, as determined by X-ray photoelectron spectroscopy, XPS, measurements. Only one CuNi alloy catalyst, Cu50Ni50/C, appeared to be as thermally stable as the Pt/C catalysts. After three temperature cycles, from 400 to 700°C, the CO yield at 700°C obtained using the Cu50Ni50/C catalyst was comparable to that obtained using a Pt/C catalyst.

  11. New Construction and Catalyst Support Materials for Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey

    in question are those for bipolar plates, gas diusion layers (GDLs), catalysts and catalyst supports. This work is focused on developing bipolar plate, GDL and catalyst support materials for the anode compartment of PEM electrolyzers, operating at elevated temperatures. The thesis starts with Chapter...... electrolysis. Chapter 4 reports results of testing dierent types of commercially available stainless steels, Ni-based alloys as well as titanium and tantalum as possible metallic bipolar plates and construction materials for HTPEMEC. The corrosion resistance was measured under simulated conditions of high...

  12. Methanol-Tolerant Cathode Catalyst Composite For Direct Methanol Fuel Cells

    Science.gov (United States)

    Zhu, Yimin; Zelenay, Piotr

    2006-03-21

    A direct methanol fuel cell (DMFC) having a methanol fuel supply, oxidant supply, and its membrane electrode assembly (MEA) formed of an anode electrode and a cathode electrode with a membrane therebetween, a methanol oxidation catalyst adjacent the anode electrode and the membrane, an oxidant reduction catalyst adjacent the cathode electrode and the membrane, comprises an oxidant reduction catalyst layer of a platinum-chromium alloy so that oxidation at the cathode of methanol that crosses from the anode through the membrane to the cathode is reduced with a concomitant increase of net electrical potential at the cathode electrode.

  13. Catalyst component interactions in nickel/alumina catalyst

    Directory of Open Access Journals (Sweden)

    Kiš Erne E.

    2007-01-01

    Full Text Available The influence of nickel loading (5; 10; 20 wt% Ni, temperature of heat treatment (400; 700; 1100°C and way of catalyst preparation on the catalyst component interactions (CCI in the impregnated, mechanical powder mixed and co-precipitated catalyst was investigated. For sample characterization, low temperature nitrogen adsorption (LTNA and X-ray diffraction (XRD were applied. Significant differences were revealed, concerning CCI in dependence of nickel loading, temperature of heat treatment and way of catalyst preparation. The obtained results show that the support metal oxide interactions (SMI in impregnated and co-precipitated catalysts are more intensive than in the mechanical powder mixed catalyst. The degree and intensity of CCI is expressed by the ratio of real and theoretical surface area of the catalyst. This ratio can be used for a quantitative estimation of CCI and it is generally applicable to all types of heterogeneous catalysts.

  14. Synergistic Effects in Bimetallic Palladium-Copper Catalysts Improve Selectivity in Oxygenate Coupling Reactions.

    Science.gov (United States)

    Goulas, Konstantinos A; Sreekumar, Sanil; Song, Yuying; Kharidehal, Purnima; Gunbas, Gorkem; Dietrich, Paul J; Johnson, Gregory R; Wang, Y C; Grippo, Adam M; Grabow, Lars C; Gokhale, Amit A; Toste, F Dean

    2016-06-01

    Condensation reactions such as Guerbet and aldol are important since they allow for C-C bond formation and give higher molecular weight oxygenates. An initial study identified Pd-supported on hydrotalcite as an active catalyst for the transformation, although this catalyst showed extensive undesirable decarbonylation. A catalyst containing Pd and Cu in a 3:1 ratio dramatically decreased decarbonylation, while preserving the high catalytic rates seen with Pd-based catalysts. A combination of XRD, EXAFS, TEM, and CO chemisorption and TPD revealed the formation of CuPd bimetallic nanoparticles with a Cu-enriched surface. Finally, density functional theory studies suggest that the surface segregation of Cu atoms in the bimetallic alloy catalyst produces Cu sites with increased reactivity, while the Pd sites responsible for unselective decarbonylation pathways are selectively poisoned by CO. PMID:27195582

  15. Deactivation-resistant catalyst for selective catalyst reduction of NOx

    OpenAIRE

    Jensen, Anker Degn; Castellino, Francesco; Rams, Per Donskov; Pedersen, Jannik Blaabjerg; Putluru, Siva Sankar Reddy

    2011-01-01

    The present invention relates to a catalyst for selective catalytic reduction of NOx in alkali metal containing flue gas using ammonia as reductant, the catalyst comprising a surface with catalytically active sites, wherein the surface is at least partly coated with a coating comprising at least one metal oxide. In another aspect the present invention relates to the use of said catalyst and to a method of producing said catalyst. In addition, the present invention relates to a method of treat...

  16. Supported organoiridium catalysts for alkane dehydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. How HIV Causes AIDS

    Science.gov (United States)

    ... Share this: Main Content Area How HIV Causes AIDS HIV destroys CD4 positive (CD4+) T cells, which ... and disease, ultimately resulting in the development of AIDS. Most people who are infected with HIV can ...

  18. HIV/AIDS Basics

    Science.gov (United States)

    ... Providers Prevention Resources Newsletter Get Tested Find an HIV testing site near you. Enter ZIP code or ... AIDS Get Email Updates on AAA Anonymous Feedback HIV/AIDS Media Infographics Syndicated Content Podcasts Slide Sets ...

  19. Aids for visual impairment.

    OpenAIRE

    Dudley, N. J.

    1990-01-01

    This article provides only a flavour of the type and range of aids available to the visually impaired person. Many other aids for leisure, learning, and daily living are illustrated in the RNIB equipment and games catalogue.

  20. AIDS Myths and Misunderstandings

    Science.gov (United States)

    ... 2014 Select a Language: Fact Sheet 158 AIDS Myths and Misunderstandings WHY ARE THERE SO MANY AIDS ... sweat, saliva or urine of an infected person. Myth: A pregnant woman with HIV infection always infects ...

  1. First Aid: Influenza (Flu)

    Science.gov (United States)

    ... Smoothie Pregnant? Your Baby's Growth First Aid: The Flu KidsHealth > For Parents > First Aid: The Flu Print ... tiredness What to Do If Your Child Has Flu Symptoms: Call your doctor. Encourage rest. Keep your ...

  2. First Aid and Safety

    Science.gov (United States)

    ... Things to Know About Zika & Pregnancy First Aid & Safety Keeping your child safe is your top priority. ... to call for help, and more. First Aid & Safety Center Home Sweet Home A Safe and Spooktacular ...

  3. MICROFICHE AIDS DATA

    Science.gov (United States)

    This data set contains counts of AIDS (Acquired Immune Deficiency Syndrome) cases reported to state and local health departments, by demographics; case-definition; HIV exposure group (risk factors for AIDS); Half-year of diagnosis, report, and death.

  4. Head injury - first aid

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000028.htm Head injury - first aid To use the sharing features on this page, ... a concussion can range from mild to severe. First Aid Learning to recognize a serious head injury and ...

  5. Drug abuse first aid

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000016.htm Drug abuse first aid To use the sharing features on this page, ... Diarrhea Hallucinations Nausea and vomiting Restlessness Shaking Death First Aid 1. Check the patient's airway, breathing, and pulse. ...

  6. Poisoning first aid

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007579.htm Poisoning first aid To use the sharing features on this page, ... or burns Stupor Unconsciousness Unusual breath odor Weakness First Aid Seek immediate medical help. For poisoning by swallowing: ...

  7. Frostbite, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Frostbite, First Aid A A A Severe frostbite can result in ... became frozen). Frostbite is often associated with hypothermia. First Aid Guide In the case of mild frostbite, the ...

  8. Jellyfish Stings, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Jellyfish Stings, First Aid A A A The rash caused by a ... to Portuguese man-of-war stings as well. First Aid Guide The rescuer should take care to avoid ...

  9. Unconsciousness, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Unconsciousness, First Aid A A A Unconsciousness signs and symptoms can ... keep the airway clear while awaiting medical care. First Aid Guide If you find an unconscious person, try ...

  10. Tick Bites, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Tick Bites, First Aid A A A It is important to inspect ... temporary paralysis in their host (called tick paralysis). First Aid Guide To remove an embedded tick: Wash your ...

  11. Heat Cramps, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Heat Cramps, First Aid A A A Heat cramp signs and symptoms ... if later stages of heat illness are suspected. First Aid Guide Use a combination of the following measures, ...

  12. Blisters, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Blisters, First Aid A A A Blisters on the feet are ... can also be found via the Disease List. First Aid Guide Blisters often go away on their own ...

  13. Heatstroke, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Heatstroke, First Aid A A A Heatstroke signs and symptoms can ... specific to the earlier stages of heat illness. First Aid Guide When heatstroke is suspected, seek emergency medical ...

  14. Heat Exhaustion, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Heat Exhaustion, First Aid A A A Heat exhaustion signs and symptoms ... specific to the other stages of heat illness. First Aid Guide Use a combination of the following measures ...

  15. First aid kit

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001958.htm First aid kit To use the sharing features on this ... ahead, you can create a well-stocked home first aid kit. Keep all of your supplies in one ...

  16. Head Trauma, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Head Trauma, First Aid A A A Head trauma signs and symptoms ... to take care for potential neck/spinal injury. First Aid Guide If you suspect either a serious head ...

  17. Bruises, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Bruises, First Aid A A A Bruises lighten and change color ... Bruises can be a sign of internal bleeding. First Aid Guide If there is external bleeding in addition ...

  18. Methanol Electro-Oxidation on Pt-Ru Alloy Nanoparticles Supported on Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yangchuan Xing

    2009-09-01

    Full Text Available Carbon nanotubes (CNTs have been investigated in recent years as a catalyst support for proton exchange membrane fuel cells. Improved catalyst activities were observed and attributed to metal-support interactions. We report a study on the kinetics of methanol electro-oxidation on CNT supported Pt-Ru alloy nanoparticles. Alloy catalysts with different compositions, Pt53Ru47/CNT, Pt69Ru31/CNT and Pt77Ru23/CNT, were prepared and investigated in detail. Experiments were conducted at various temperatures, electrode potentials, and methanol concentrations. It was found that the reaction order of methanol electro-oxidation on the PtRu/CNT catalysts was consistent with what has been reported for PtRu alloys with a value of 0.5 in methanol concentrations. However, the electro-oxidation reaction on the PtRu/CNT catalysts displayed much lower activation energies than that on the Pt-Ru alloy catalysts unsupported or supported on carbon black (PtRu/CB. This study provides an overall kinetic evaluation of the PtRu/CNT catalysts and further demonstrates the beneficial role of CNTs.

  19. Fiscal effects of aid

    OpenAIRE

    Timmis, Emilija

    2015-01-01

    This thesis analyses fiscal effects of aid, first of health aid on health spending for a sample of developing countries and then broadly for Ethiopia and Tanzania. Particular attention is paid to data quality and the severe difficulties in achieving a reliable disaggregation of aid into its on-budget and off-budget components. The first essay assesses the sensitivity of estimated health aid fungibility to how the missing data (often considerable) are treated and explores a novel (at least in...

  20. Studying Aid: Some Methods

    OpenAIRE

    Gasper, Des

    2003-01-01

    textabstractINVESTIGATING IDEAS, IDEOLOGIES AND PRACTICES This paper presents some methods for trying to make sense of international aid and of its study.1 Some of the methods may be deemed ethnographic; the others are important partners to them, but rather different. In the course of discussing questions of aid policy and practice—such as: Should international development aid exist at all? How should aid be conducted? Should humanitarian relief be provided in conflict situations when it can ...

  1. Aid and Development

    OpenAIRE

    Tarp, Finn

    2006-01-01

    Foreign aid looms large in the public discourse; and international development assistance remains squarely on most policy agendas concerned with growth, poverty and inequality in Africa and elsewhere in the developing world. The present review takes a retrospective look at how foreign aid has evolved since World War II in response to a dramatically changing global political and economic context. I review the aid process and associated trends in the volume and distribution of aid and categoriz...

  2. First Aid: Falls

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Falls KidsHealth > For Parents > First Aid: Falls Print A A A Text Size en ... Floors, Doors & Windows, Furniture, Stairways: Household Safety Checklist First Aid: Broken Bones Head Injuries Preventing Children's Sports Injuries ...

  3. First Aid: Rashes

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Rashes KidsHealth > For Parents > First Aid: Rashes Print A A A Text Size Rashes ... For Kids For Parents MORE ON THIS TOPIC First Aid: Skin Infections Poison Ivy Erythema Multiforme Hives (Urticaria) ...

  4. First Aid: Dehydration

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Dehydration KidsHealth > For Parents > First Aid: Dehydration Print A A A Text Size Dehydration ... MORE ON THIS TOPIC Summer Safety Heat Illness First Aid: Heat Illness Sun Safety Dehydration Diarrhea Vomiting Word! ...

  5. First Aid: Burns

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Burns KidsHealth > For Parents > First Aid: Burns Print A A A Text Size Scald ... THIS TOPIC Kitchen: Household Safety Checklist Fireworks Safety First Aid: Sunburn Firesetting Fire Safety Burns Household Safety: Preventing ...

  6. First Aid: Choking

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Choking KidsHealth > For Parents > First Aid: Choking Print A A A Text Size Choking ... usually are taught as part of any basic first-aid course. Reviewed by: Steven Dowshen, MD Date reviewed: ...

  7. First Aid: Animal Bites

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Animal Bites KidsHealth > For Parents > First Aid: Animal Bites Print A A A Text Size ... For Kids For Parents MORE ON THIS TOPIC First Aid & Safety Center Infections That Pets Carry Dealing With ...

  8. First Aid: Croup

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Croup KidsHealth > For Parents > First Aid: Croup Print A A A Text Size Croup ... For Kids For Parents MORE ON THIS TOPIC First Aid: Coughing X-Ray Exam: Neck Why Is Hand ...

  9. Dynamics of Catalyst Nanoparticles

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Cavalca, Filippo; Wagner, Jakob Birkedal

    under gas exposure, dynamic phenomena such as sintering and growth can be observed with sub-Ångstrøm resolution. Metal nanoparticles contain the active sites in heterogeneous catalysts, which are important for many industrial applications including the production of clean fuels, chemicals...... and pharmaceuticals, and the cleanup of exhaust from automobiles and stationary power plants. Sintering, or thermal deactivation, is an important mechanism for the loss of catalyst activity. In order to initiate a systematic study of the dynamics and sintering of nanoparticles, various catalytic systems have been...

  10. Electronic-Structure-Based Design of Ordered Alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Andersson, M.P.; Jacobsen, Karsten Wedel; Skriver, Hans Lomholt; Christensen, Claus H.; Nørskov, Jens Kehlet

    2006-01-01

    We describe some recent advances in the methodology of using electronic structure calculations for materials design. The methods have been developed for the design of ordered metallic alloys and metal alloy catalysts, but the considerations we present are relevant for the atomic-scale computational...... discovery of a promising catalytic metal alloy surface with high reactivity and low cost....... design of other materials as well. A central problem is how to treat the huge number of compounds that can be envisioned by varying the concentrations and the number of the elements involved. We discuss various strategies for approaching this problem and show how one strategy has led to the computational...

  11. Fuel cell applications for novel metalloporphyrin catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ryba, G.; Shelnutt, J.; Doddapaneni, N.; Zavadil, K.

    1997-04-01

    This project utilized Computer-Aided Molecular Design (CAMD) to develop a new class of metalloporphyrin materials for use as catalysts for two fuel cell reactions. The first reaction is the reduction of oxygen at the fuel cell cathode, and this reaction was the main focus of the research. The second reaction we attempted to catalyze was the oxidation of methanol at the anode. Two classes of novel metalloporphyrins were developed. The first class comprised the dodecaphenylporphyrins whose steric bulk forces them into a non-planar geometry having a pocket where oxygen or methanol is more tightly bound to the porphyrin than it is in the case of planar porphyrins. Significant improvements in the catalytic reduction of oxygen by the dodecaphenyl porphyrins were measured in electrochemical cells. The dodecaphenylporphyrins were further modified by fluorinating the peripheral phenyl groups to varying degrees. The fluorination strongly affected their redox potential, but no effect on their catalytic activity towards oxygen was observed. The second class of porphyrin catalysts was a series of hydrogen-bonding porphyrins whose interaction with oxygen is enhanced. Enhancements in the interaction of oxygen with the porphyrins having hydrogen bonding groups were observed spectroscopically. Computer modeling was performed using Molecular Simulations new CERIUS2 Version 1.6 and a research version of POLYGRAF from Bill Goddard`s research group at the California Institute of Technology. We reoptimized the force field because of an error that was in POLYGRAF and corrected a problem in treatment of the metal in early versions of the program. This improved force field was reported in a J. Am. Chem. Soc. manuscript. Experimental measurements made on the newly developed catalysts included the electrochemical testing in a fuel cell configuration and spectroscopic measurements (UV-Vis, Raman and XPS) to characterize the catalysts.

  12. Aid with Multiple Personalities

    OpenAIRE

    Djankov, Simeon; Jose G. Montalvo; Reynal-Querol, Marta

    2009-01-01

    The existing research on foreign aid offers inconclusive evidence on the factors that make aid effective. In this paper, we study the supply of aid money in 112 developing countries over the period 1960-1999 and find that the presence of multiple donors in a given country renders aid less effective. In particular, an aid-receiving country at the median of the donor fractionalization distribution will grow one percentage point faster than a country at the 75th percentile. This is in part becau...

  13. Why foreign aid fails

    Directory of Open Access Journals (Sweden)

    Prokopijević Miroslav

    2007-01-01

    Full Text Available The main point of this paper is that foreign aid fails because the structure of its incentives resembles that of central planning. Aid is not only ineffective, it is arguably counterproductive. Contrary to business firms that are paid by those they are supposed to serve (customers, aid agencies are paid by tax payers of developed countries and not by those they serve. This inverse structure of incentives breaks the stream of pressure that exists on the commercial market. It also creates larger loopholes in the principle-agent relationship on each point along the chain of aid delivery. Both factors enhance corruption, moral hazard and negative selection. Instead of promoting development, aid extends the life of bad institutions and those in power. Proposals to reform foreign aid – like aid privatization and aid conditionality – do not change the existing structure of the incentives in aid delivery, and their implementation may just slightly improve aid efficacy. Larger improvement is not possible. For that reason, foreign aid will continue to be a waste of resources, probably serving some objectives different to those that are usually mentioned, like recipient’s development poverty reduction and pain relief.

  14. Conditional Aid Effectiveness

    DEFF Research Database (Denmark)

    Doucouliagos, Hristos; Paldam, Martin

    The AEL (aid effectiveness literature) studies the effect of development aid using econometrics on macro data. It contains about 100 papers of which a third analyzes conditional models where aid effectiveness depends upon z, so that aid only works for a certain range of the variable. The key term...... in this family of AEL models is thus an interaction term of z times aid. The leading candidates for z are a good policy index and aid itself. In this paper, meta-analysis techniques are used (i) to determine whether the AEL has established the said interaction terms, and (ii) to identify some of the...... determinants of the differences in results between studies. Taking all available studies in consideration, we find no support for conditionality with respect to policy, while conditionality regarding aid itself is dubious. However, the results differ depending on the authors’ institutional affiliation....

  15. China vs. AIDS

    Institute of Scientific and Technical Information of China (English)

    LURUCAI

    2004-01-01

    CHINA's first HIV positive diagnosis was in 1985, the victim an ArgentineAmerican. At that time most Chinese,medical workers included, thought of AIDS as a phenomenon occurring outside of China. Twenty years later, the number of HIV/AIDS patients has risen alarmingly. In 2003, the Chinese Ministry of Health launched an AIDS Epidemiological Investigation across China with the support of the WHO and UN AIDS Program. Its results show that there are currently 840,000 HIV carriers, including 80,000 people with full-blown AIDS, in 31 Chinese provinces, municipalities and autonomous regions. This means China has the second highest number of HIV/AIDS cases in Asia and 14th highest in the world. Statistics from the Chinese Venereal Disease and AIDS Prevention Association indicate that the majority of Chinese HIV carriers are young to middle aged, more than half of them between the ages of 20 and 29.

  16. HIV, AIDS, and the Future

    Science.gov (United States)

    ... Navigation Bar Home Current Issue Past Issues HIV / AIDS HIV, AIDS, and the Future Past Issues / Summer 2009 Table ... and your loved ones from HIV/AIDS. The AIDS Memorial Quilt In 1987, a total of 1, ...

  17. Catalysts for Environmental Remediation

    DEFF Research Database (Denmark)

    Abrams, B. L.; Vesborg, Peter Christian Kjærgaard

    2013-01-01

    The properties of catalysts used in environmental remediation are described here through specific examples in heterogeneous catalysis and photocatalysis. In the area of heterogeneous catalysis, selective catalytic reduction (SCR) of NOx was used as an example reaction with vanadia and tungsta on...

  18. Tight bifunctional hierarchical catalyst.

    Science.gov (United States)

    Højholt, Karen T; Vennestrøm, Peter N R; Tiruvalam, Ramchandra; Beato, Pablo

    2011-12-28

    A new concept to prepare tight bifunctional catalysts has been developed, by anchoring CoMo(6) clusters on hierarchical ZSM-5 zeolites for simultaneous use in HDS and hydrocracking catalysis. The prepared material displays a significant improved activity in HDS catalysis compared to the impregnated counterpart. PMID:22048337

  19. Hydrogen evolution reaction catalyst

    Science.gov (United States)

    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.

  20. Formic acid oxidation at platinum-bismuth catalysts

    Directory of Open Access Journals (Sweden)

    Popović Ksenija Đ.

    2015-01-01

    Full Text Available The field of heterogeneous catalysis, specifically catalysis on bimetallic surfaces, has seen many advances over the past few decades. Bimetallic catalysts, which often show electronic and chemical properties that are distinct from those of their parent metals, offer the opportunity to obtain new catalysts with enhanced selectivity, activity, and stability. The oxidation of formic acid is of permanent interest as a model reaction for the mechanistic understanding of the electrooxidation of small organic molecules and because of its technical relevance for fuel cell applications. Platinum is one of the most commonly used catalysts for this reaction, despite the fact that it shows a few significant disadvantages: high cost and extreme susceptibility to poisoning by CO. To solve this problem, several approaches have been used, but generally, they all consist in the modification of platinum with a second element. Especially, bismuth has received significant attention as Pt modifier. According to the results presented in this survey dealing with the effects influencing the formic acid oxidation it was found that two types of Pt-Bi bimetallic catalysts (bulk and low loading deposits on GC showed superior catalytic activity in terms of the lower onset potential and oxidation current density, as well as exceptional stability compared to Pt. The findings in this report are important for the understanding of mechanism of formic acid electrooxidation on a bulk alloy and decorated surface, for the development of advanced anode catalysts for direct formic acid fuel cells, as well as for the synthesis of novel low-loading bimetallic catalysts. The use of bimetallic compounds as the anode catalysts is an effective solution to overcoming the problems of the formic acid oxidation current stability for long term applications. In the future, the tolerance of both CO poisoning and electrochemical leaching should be considered as the key factors in the development

  1. Using supported Au nanoparticles as starting material for preparing uniform Au/Pd bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Villa, Alberto [Universita di Milano, Italy; Prati, Laura [Universita di Milano, Italy; Su, Dangshen [Fritz Haber Institute of the Max Planck Society, Berlin, Germany; Wang, Di [Fritz Haber Institute of the Max Planck Society, Berlin, Germany; Veith, Gabriel M [ORNL

    2010-01-01

    One of the best methods for producing bulk homogeneous (composition) supported bimetallic AuPd clusters involves the immobilization of a protected Au seed followed by the addition of Pd. This paper investigates the importance of this gold seed in controlling the resulting bimetallic AuPd clusters structures, sizes and catalytic activities by investigating three different gold seeds. Uniform Au-Pd alloy were obtained when a steric/electrostatic protecting group, poly(vinyl alcohol) (PVA), was used to form the gold clusters on activated carbon (AC). In contrast Au/AC precursors prepared using Au nanoparticles with only electrostatic stabilization (tetrakis(hydroxypropyl)phosphonium chloride (THPC)), or no stabilization (magnetron sputtering) produced inhomogeneous alloys and segregation of the gold and palladium. The uniform alloyed catalyst (Pd{at}Au{sub PVA}/AC) is the most active and selective catalyst, while the inhomogenous catalysts are less active and selective. Further study of the PVA protected Au clusters revealed that the amount of PVA used is also critical for the preparation of uniform alloyed catalyst, their stability, and their catalytic activity.

  2. On the Role of Surface Modifications of Palladium Catalysts in the Selective Hydrogenation of Acetylene

    DEFF Research Database (Denmark)

    Studt, Felix; Abild-Pedersen, Frank; Bligaard, Thomas;

    2008-01-01

    Summing Me up: DFT calculations have shown that alloying, subsurface carbon, and hydride formation, all increase the selectivity of Pd catalysts for acetylene hydrogenation by weakening the surface–adsorbate bond. A simple descriptor—the adsorption energy of a methyl group—has been used to quanti...

  3. Synthesis of nickel-based skeletal catalyst for an alkaline electrolyzer

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, W.M.; Fernandez, A.M. [Universidad Nacional Autonoma de Mexico, Centro de Investigacion en Energia, Av. Xochicalco s/n, Col. Centro, 62580 Temixco, Morelos (Mexico); Cano, U. [Gerencia de Energias No Convencionales, Instituto de Investigaciones Electricas (IIE), Av. Reforma 113, Col. Palmira 62490, Cuernavaca, Mor. (Mexico); Sandoval J, A. [Instituto de Investigaciones Nucleares, Carretera Mexico-Toluca S/N (Km. 36.5), La Marquesa, Ocoyoacac, Mexico C.P.

    2010-08-15

    A method for preparing Nickel-based skeletal catalyst as well as its characterization is reported. The catalyst has an intended use as a cathode in alkaline electrolysis. Skeletal catalyst electrodes were synthesized from equal weights (50% each) of aluminum and nickel powders. The catalyst was prepared with metal powders which were melted in an induction oven, allowing the alloy to solidify at room temperature to obtain the thermodynamically-stable phases of the alloy. Samples from the resulting alloy went through a leaching process in an alkaline solution using two different leaching times. After leaching, porous and amorphous electrodes were obtained and then subjected to a slow oxidative stage to avoid ignition. The structure, composition, morphology and electrochemical characteristics of the electrodes were studied. The leached samples showed a high exchange current density indicating that are good catalysts for the Hydrogen Evolution Reaction (HER), a property enhanced by the adsorption of hydrogen during the leaching process which facilitated the hydrogen reduction overall reaction. (author)

  4. What Is the Optimum Strain for Pt Alloys for Oxygen Electroreduction?

    DEFF Research Database (Denmark)

    Escribano, Maria Escudero; Malacrida, Paolo; Velazquez-Palenzuela, Amado Andres;

    2015-01-01

    In order to make low-temperature fuel cells commercially viable, it is crucial to develop oxygen reduction catalysts based on more active, stable and abundant materials. A fruitful strategy for enhancing the oxygen reduction reaction (ORR) activity is to alloy Pt with transition metals [1]. However...... trends in activity and stability novel Pt-lanthanide (Pt-Ln) alloys as efficient ORR catalysts. Sputter-cleaned, polycrystalline Pt5Gd shows a 5-fold increase in ORR activity [3], relative to Pt. All the Pt-lanthanide alloys are at least 3 times more active than Pt for the ORR [3-5]. A compressed Pt...... overlayer is formed onto the bulk alloy. Accordingly, the effect of alloying Pt is to impose strain onto the Pt overlayer [3-5]. It is likely that this strain would be relaxed by defects [6]. The activity of the Pt-based electrocatalysts versus the lattice parameter in the bulk shows a volcano relationship...

  5. Effects of copper-based alloy on the synthesis of single-crystal diamond

    CERN Document Server

    Chen Li Xue; Ma Hong An; Jia Xiao Peng; Wakatsuki, M; Zou Guang Tian

    2002-01-01

    The catalytic effects of copper-based alloys in diamond growth have been investigated. A single crystal of diamond has been obtained by the temperature gradient method (TGM), using Cu-Mn-Co and Cu-Co alloys as catalysts. It was found that the melted Cu-Mn-Co and Cu-Co alloys show low viscosity. The eutectic temperatures of these two alloys with graphite were between 1130 and 1150 deg. C, and the temperature of the transition to diamond was over 1300 deg. C at 5.5 GPa. High-quality diamond could not be obtained in Cu-Co alloy by the TGM. Our results suggest that adding Cu to a catalyst cannot decrease the reaction temperature for diamond growth.

  6. Aid Effectiveness on Growth

    DEFF Research Database (Denmark)

    Doucouliagos, Hristos; Paldam, Martin

    The AEL (aid effectiveness literature) is econo¬metric studies of the macroeconomic effects of development aid. It contains about 100 papers of which 68 are reduced form estimates of theeffect of aid on growth in the recipient country. The raw data show that growth is unconnected to aid, but the...... AEL has put so much structure on the data that all results possible have emerged. The present meta study considers both the best-set of the 68 papers and the all-set of 543 regressions published. Both sets have a positive average aid-growth elasticity, but it is small and insignificant: The AEL has...... not established that aid works. Using meta-regression analysis it is shown that about 20 factors influence the results. Much of the variation between studies is an artifact and can be attributed to publication outlet, institu¬tional affiliation, and specification differences. However, some of the...

  7. Aid and Growth

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    , are being drawn on the basis of fragile evidence. This paper first assesses the aid-growth literature with a focus on recent contributions. The aid-growth literature is then framed, for the first time, in terms of the Rubin Causal Model, applied at the macroeconomic level. Our results show that aid......The micro-macro paradox has been revived. Despite broadly positive evaluations at the micro and meso-levels, recent literature has turned decidedly pessimistic with respect to the ability of foreign aid to foster economic growth. Policy implications, such as the complete cessation of aid to Africa...... has a positive and statistically significant causal effect on growth over the long run with point estimates at levels suggested by growth theory. We conclude that aid remains an important tool for enhancing the development prospects of poor nations....

  8. Towards a general growth model for graphene CVD on transition metal catalysts

    Science.gov (United States)

    Cabrero-Vilatela, Andrea; Weatherup, Robert S.; Braeuninger-Weimer, Philipp; Caneva, Sabina; Hofmann, Stephan

    2016-01-01

    The chemical vapour deposition (CVD) of graphene on three polycrystalline transition metal catalysts, Co, Ni and Cu, is systematically compared and a first-order growth model is proposed which can serve as a reference to optimize graphene growth on any elemental or alloy catalyst system. Simple thermodynamic considerations of carbon solubility are insufficient to capture even basic growth behaviour on these most commonly used catalyst materials, and it is shown that kinetic aspects such as carbon permeation have to be taken into account. Key CVD process parameters are discussed in this context and the results are anticipated to be highly useful for the design of future strategies for integrated graphene manufacture.The chemical vapour deposition (CVD) of graphene on three polycrystalline transition metal catalysts, Co, Ni and Cu, is systematically compared and a first-order growth model is proposed which can serve as a reference to optimize graphene growth on any elemental or alloy catalyst system. Simple thermodynamic considerations of carbon solubility are insufficient to capture even basic growth behaviour on these most commonly used catalyst materials, and it is shown that kinetic aspects such as carbon permeation have to be taken into account. Key CVD process parameters are discussed in this context and the results are anticipated to be highly useful for the design of future strategies for integrated graphene manufacture. Electronic supplementary information (ESI) available: Fig. S1. See DOI: 10.1039/c5nr06873h

  9. On the stability of the CO adsorption-induced and self-organized CuPt surface alloy

    DEFF Research Database (Denmark)

    Andersson, Klas Jerker; Chorkendorff, Ib

    2010-01-01

    regenerated by reducing the CuOx in 100 mbar CO for 10 min at room temperature. The results show, amongst others, the stability of the CuPt surface alloy in various environments containing CO and how a novel coinage/Pt-group bimetallic surface alloy catalyst induced by CO adsorption can be reactivated before...

  10. Hearing Aids and Music

    OpenAIRE

    Chasin, Marshall; Russo, Frank A.

    2004-01-01

    Historically, the primary concern for hearing aid design and fitting is optimization for speech inputs. However, increasingly other types of inputs are being investigated and this is certainly the case for music. Whether the hearing aid wearer is a musician or merely someone who likes to listen to music, the electronic and electro-acoustic parameters described can be optimized for music as well as for speech. That is, a hearing aid optimally set for music can be optimally set for speech, even...

  11. Radiographic imaging of aids

    International Nuclear Information System (INIS)

    The acquired immunodeficiency syndrome (AIDS) has impacted the civilized world like no other disease. This research aimed to discuss some of the main aids-related complications and their detection by radiology tests, specifically central nervous system and musculoskeletal system disorders. The objectives are: to show specific characteristics of various diseases of HIV patient, to analyze the effect of pathology in patients by radiology, to enhance the knowledge of technologists in aids imaging and to improve communication skills between patient and radiology technologists

  12. Radiographic imaging of aids

    CERN Document Server

    Mahmoud, M B

    2002-01-01

    The acquired immunodeficiency syndrome (AIDS) has impacted the civilized world like no other disease. This research aimed to discuss some of the main aids-related complications and their detection by radiology tests, specifically central nervous system and musculoskeletal system disorders. The objectives are: to show specific characteristics of various diseases of HIV patient, to analyze the effect of pathology in patients by radiology, to enhance the knowledge of technologists in aids imaging and to improve communication skills between patient and radiology technologists.

  13. AIDS: acquired immunodeficiency syndrome

    OpenAIRE

    Gilmore, N. J.; Beaulieu, R.; Steben, M.; Laverdière, M.

    2002-01-01

    Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Ca...

  14. Aid, growth, and development

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    2010-01-01

    The micro-macro paradox has been revived. Despite broadly positive evaluations at the micro- and meso-levels, recent literature doubts the ability of foreign aid to foster economic growth and development. This paper assesses the aid-growth literature and, taking inspiration from the program...... evaluation literature, we re-examine key hypotheses. In our findings, aid has a positive and statistically significant causal effect on growth over the long run, with confidence intervals conforming to levels suggested by growth theory. Aid remains a key tool for enhancing the development prospects of poor...

  15. Music and hearing aids.

    Science.gov (United States)

    Madsen, Sara M K; Moore, Brian C J

    2014-01-01

    The signal processing and fitting methods used for hearing aids have mainly been designed to optimize the intelligibility of speech. Little attention has been paid to the effectiveness of hearing aids for listening to music. Perhaps as a consequence, many hearing-aid users complain that they are not satisfied with their hearing aids when listening to music. This issue inspired the Internet-based survey presented here. The survey was designed to identify the nature and prevalence of problems associated with listening to live and reproduced music with hearing aids. Responses from 523 hearing-aid users to 21 multiple-choice questions are presented and analyzed, and the relationships between responses to questions regarding music and questions concerned with information about the respondents, their hearing aids, and their hearing loss are described. Large proportions of the respondents reported that they found their hearing aids to be helpful for listening to both live and reproduced music, although less so for the former. The survey also identified problems such as distortion, acoustic feedback, insufficient or excessive gain, unbalanced frequency response, and reduced tone quality. The results indicate that the enjoyment of listening to music with hearing aids could be improved by an increase of the input and output dynamic range, extension of the low-frequency response, and improvement of feedback cancellation and automatic gain control systems. PMID:25361601

  16. HIV / AIDS Network.

    Science.gov (United States)

    1995-01-01

    The HIV/AIDS Network and the Philippines Department of Health (DOH) collaborated to produce the AIDS Candlelight Memorial at the Philippine International Convention Center (PICC), May 1995, and World AIDS Day activities on December 1, 1995. After the memorial, a fashion show, "Body Shots," provided a channel for information on acquired immunodeficiency syndrome (AIDS). On World AIDS Day, at the request of DOH, the Network provided speakers who lectured on human immunodeficiency virus (HIV) and AIDS in different government offices. Prior to World AIDS Day, the Network focused on strengthening its cohesiveness and building the capabilities of its member organizations through lectures and symposia during November. Network activities were coordinated by the Remedios AIDS Foundation with support from the other members of the Coordinating Council: Health Action Information Network (HAIN); Caritas; Kabalikat, Stop Trafficking of Pilopinos Foundation, Inc. (STOP);and the Library Foundation (TLF). The Coordinating Council elected for 1996 includes the Remedios AIDS Foundation, HAIN, Caritas, TLF, STOP, the Foundation for Adolescent Development (FAD), and the Salvation Army. PMID:12291699

  17. Vanadium alloys: development strategy

    International Nuclear Information System (INIS)

    A strategy for the development of vanadium alloys for use in radiation environments is outlined. An attractive reference alloy (V-15Cr-5Ti) has been identified. The critical issues in developing vanadium base alloys are summarized

  18. Platinum and palladium alloys suitable as fuel cell electrodes

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention concerns electrode catalysts used in fuel cells, such as proton exchange membrane (PEM) fuel cells. The invention is related to the reduction of the noble metal content and the improvement of the catalytic efficiency by low level substitution of the noble metal to provide ne...... and innovative catalyst compositions in fuel cell electrodes. The novel electrode catalysts of the invention comprise a noble metal selected from Pt and Pd alloyed with an alkaline earth metal.......The present invention concerns electrode catalysts used in fuel cells, such as proton exchange membrane (PEM) fuel cells. The invention is related to the reduction of the noble metal content and the improvement of the catalytic efficiency by low level substitution of the noble metal to provide new...

  19. AIDS is your business.

    Science.gov (United States)

    Rosen, Sydney; Simon, Jonathon; Vincent, Jeffrey R; MacLeod, William; Fox, Matthew; Thea, Donald M

    2003-02-01

    If your company operates in a developing country, AIDS is your business. While Africa has received the most attention, AIDS is also spreading swiftly in other parts of the world. Russia and Ukraine had the fastest-growing epidemics last year, and many experts believe China and India will suffer the next tidal wave of infection. Why should executives be concerned about AIDS? Because it is destroying the twin rationales of globalization strategy-cheap labor and fast-growing markets--in countries where people are heavily affected by the epidemic. Fortunately, investments in programs that prevent infection and provide treatment for employees who have HIV/AIDS are profitable for many businesses--that is, they lead to savings that outweigh the programs' costs. Due to the long latency period between HIV infection and the onset of AIDS symptoms, a company is not likely to see any of the costs of HIV/AIDS until five to ten years after an employee is infected. But executives can calculate the present value of epidemic-related costs by using the discount rate to weigh each cost according to its expected timing. That allows companies to think about expenses on HIV/AIDS prevention and treatment programs as investments rather than merely as costs. The authors found that the annual cost of AIDS to six corporations in South Africa and Botswana ranged from 0.4% to 5.9% of the wage bill. All six companies would have earned positive returns on their investments if they had provided employees with free treatment for HIV/AIDS in the form of highly active antiretroviral therapy (HAART), according to the mathematical model the authors used. The annual reduction in the AIDS "tax" would have been as much as 40.4%. The authors' conclusion? Fighting AIDS not only helps those infected; it also makes good business sense. PMID:12577655

  20. Supported Copper, Nickel and Copper-Nickel Nanoparticle Catalysts for Low Temperature Water-Gas-Shift Reaction

    Science.gov (United States)

    Lin, Jiann-Horng

    Hydrogen is being considered worldwide as a future replacement for gasoline, diesel fuel, natural gas in both the transportation and non-transportation sectors. Hydrogen is a versatile energy carrier that can be produced from a variety of widely available primary energy sources, including coal, natural gas, biomass, solar, wind, and nuclear power. Coal, the most abundant fossil fuel on the planet, is being looked at as the possible future major source of H2, due to the development of the integrated gasification combined cycle (IGCC) and integrated gasification fuel cell technologies (IGFC). The gasification of coal produces syngas consisting of predominately carbon monoxide and hydrogen with some remaining hydrocarbons, carbon dioxide and water. Then, the water-gas shift reaction is used to convert CO to CO2 and additional hydrogen. The present work describes the synthesis of model Cu, Ni and Cu-Ni catalysts prepared from metal colloids, and compares their behavior in the WGS reaction to that of traditional impregnation catalysts. Initially, we systematically explored the performance of traditional Cu, Ni and Cu-Ni WGS catalysts made by impregnation methods. Various bimetallic Cu-Ni catalysts were prepared by supported impregnation and compared to monometallic Cu and Ni catalysts. The presence of Cu in bimetallic catalysts suppressed undesirable methanation side reaction, while the Ni component was important for high WGS activity. Colloidal Cu, Ni and Cu-Ni alloy nanoparticles obtained by chemical reduction were deposited onto alumina to prepare supported catalysts. The resulting Cu and Ni nanoparticle catalysts were found to be 2.5 times more active in the WGS reaction per unit mass of active metal as compared to catalysts prepared by the conventional impregnation technique. The powder XRD and HAADF-STEM provided evidence supporting the formation of Cu-Ni particles containing the Cu core and Cu-Ni alloy shell. The XPS data indicated surface segregation of Cu in

  1. International Aid to Education

    Science.gov (United States)

    Benavot, Aaron

    2010-01-01

    Recent evidence highlights several worrisome trends regarding aid pledges and disbursements, which have been exacerbated by the global financial crisis. First, while overall development assistance rose in 2008, after 2 years of decline, the share of all sector aid going to the education sector has remained virtually unchanged at about 12 percent…

  2. AIDS Epidemiological models

    Science.gov (United States)

    Rahmani, Fouad Lazhar

    2010-11-01

    The aim of this paper is to present mathematical modelling of the spread of infection in the context of the transmission of the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS). These models are based in part on the models suggested in the field of th AIDS mathematical modelling as reported by ISHAM [6].

  3. Genetic Immunity to AIDS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In an article on genetic immunity to AIDS published in Science magazine, American and Chinese scientists claim to have discovered why certain HIV carriers do not develop full-blown AIDS. They say that the key to this conundrum lies in a particular protein in the endocrine system that inhibits development of HIV.

  4. Aid and Income

    DEFF Research Database (Denmark)

    Lof, Matthijs; Mekasha, Tseday Jemaneh; Tarp, Finn

    2015-01-01

    to nonrandom omission of a large proportion of observations. Furthermore, we show that NDHKM’s use of co-integrated regressions is not a suitable empirical strategy for estimating the causal effect of aid on income. Evidence from a Panel VAR model estimated on the dataset of NDHKM, suggests a...... positive and statistically significant long-run effect of aid on income....

  5. AIDS and Chemical Dependency.

    Science.gov (United States)

    Pohl, Melvin I.

    After defining HIV and the AIDS disease and outlining symptoms and means of infection, this fact sheet lists the ways alcohol and drugs are involved with the AIDS epidemic, noting that needle-sharing transmits the virus; that alcohol or mood-altering drugs like crack cocaine cause disinhibition, increase sex drive, encourage sex for drugs, and…

  6. [Oral hygiene aids].

    Science.gov (United States)

    Hovius, M; Leemans, G J

    1994-05-01

    Different dental hygiene aids are discussed, such as floss, tape, superfloss, gauze, flat shoelace, toothpick, interproximal brush, single-tufted brush, electric toothbrush, manual toothbrush and oral irrigation. Research shows that not one specific aid is superior to another if effectiveness is taken into consideration. Other factors which can influence oral hygiene efficacy are discussed as well. PMID:11830968

  7. Changing epidemiology of AIDS.

    OpenAIRE

    Donovan, C. A.; Stratton, E.

    1994-01-01

    It has been 15 years since AIDS made its first appearance in North America, probably longer worldwide. In that time, our knowledge of the epidemiology of AIDS has grown and changed. This review highlights significant aspects of the epidemic with particular emphasis on the evolution of this disease in North America.

  8. Hearing aid and Noise

    OpenAIRE

    Ahmad Reza Nazeri

    1999-01-01

    Prescription of hearing aid is an extensive special category of knowledge in the field of audiology. This article is aimed at discussing the function of hearing aid and also management of patients in the noisy environments and presenting solutions to overcome problems regarding to this issue along with taking a look to the equipments prepared nowadays to cope with noisy situations.

  9. Aid and sectoral growth

    DEFF Research Database (Denmark)

    Selaya, Pablo; Thiele, Rainer

    2010-01-01

    This article examines empirically the proposition that aid to poor countries is detrimental for external competitiveness, giving rise to Dutch disease type effects. At the aggregate level, aid is found to have a positive effect on growth. A sectoral decomposition shows that the effect is (i) sign...... labour capacity that prevents the real exchange rate from appreciating....

  10. Influence of preparation method on supported Cu-Ni alloys and their catalytic properties in high pressure CO hydrogenation

    DEFF Research Database (Denmark)

    Wu, Qiongxiao; Eriksen, Winnie L.; Duchstein, Linus Daniel Leonhard;

    2014-01-01

    (50 bar CO and 50 bar H2). These alloy catalysts are highly selective (more than 99 mol%) and active for methanol synthesis; however, loss of Ni caused by nickel carbonyl formation is found to be a serious issue. The Ni carbonyl formation should be considered, if Ni-containing catalysts (even in...... impregnation, the coprecipitation and deposition-coprecipitation methods are more efficient for preparation of small and homogeneous Cu-Ni alloy nanoparticles. In order to examine the stability of Cu-Ni alloys in high pressure synthesis gas conversion, they have been tested for high pressure CO hydrogenation...

  11. Oxygen-reducing catalyst layer

    Science.gov (United States)

    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.

  12. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States); Benavides, Pahola T. [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States)

    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.

  13. Privileged chiral ligands and catalysts

    CERN Document Server

    Zhou, Qi-Lin

    2011-01-01

    This ultimate ""must have"" and long awaited reference for every chemist working in the field of asymmetric catalysis starts with the core structure of the catalysts, explaining why a certain ligand or catalyst is so successful. It describes in detail the history, the basic structural characteristics, and the applications of these ""privileged catalysts"". A novel concept that gives readers a much deeper insight into the topic.

  14. Precious-metal-free automotive catalyst in the elements science and technology project

    International Nuclear Information System (INIS)

    Self-regeneration of the intelligent catalyst as an automotive catalyst was observed by in-situ XAFS. Palladium nano-particles in catalytic reaction were also observed to elucidate the difference in activity between the intelligent catalyst and the conventional one. Copper has been investigated as a candidate to replace precious metals since the first-principle theory predicts an active copper surface for NO dissociation. The redox property of Cu turned into a similar property of precious metals by managing the interaction between Cu particles and a substrate. The conversion efficiency of Ni-Cu alloy particles increased than each element alone. The Ni was oxidized faster than the Cu so as to maintain a metallic surface of Cu. These properties of Cu were incorporated into new design of a Cu catalyst, which has achieved high catalytic activity with the regular operation of engine in the beginning. (author)

  15. Implementing AIDS Education

    Directory of Open Access Journals (Sweden)

    Grace C. Huerta

    1996-08-01

    Full Text Available The world has been challenged by the AIDS epidemic for 15 years. In 1985, the U.S. Department of Health and Human Services, Centers for Disease Control, allocated funds to all state departments of education to assist schools in the development of AIDS education policies and programs. Yet, these policies do not ensure that all students receive effective AIDS education. On September 21, 1991, the Arizona Legislature passed Senate Bill 1396, which requires public schools to annually provide AIDS education in grades K-12. The bill was rescinded in 1995. With prohibitive curriculum guidelines, limited teacher training opportunities and tremendous instructional demands, this educational policy was implemented in disparate forms. By examining the perspectives of the Arizona educators (representing three school districts, this qualitative study reveals how teachers ultimately controlled the delivery and nature of AIDS instruction based upon personal values, views of teacher roles, and their interpretation of the mandate itself.

  16. Reuse of Hydrotreating Spent Catalyst

    International Nuclear Information System (INIS)

    All hydro treating catalysts used in petroleum refining processes gradually lose activity through coking, poisoning by metal, sulfur or halides or lose surface area from sintering at high process temperatures. Waste hydrotreating catalyst, which have been used in re-refining of waste lube oil at Alexandria Petroleum Company (after 5 years lifetime) compared with the same fresh catalyst were used in the present work. Studies are conducted on partial extraction of the active metals of spent catalyst (Mo and Ni) using three leaching solvents,4% oxidized oxalic acid, 10% aqueous sodium hydroxide and 10% citric acid. The leaching experiments are conducting on the de coked extrude [un crushed] spent catalyst samples. These steps are carried out in order to rejuvenate the spent catalyst to be reused in other reactions. The results indicated that 4% oxidized oxalic acid leaching solution gave total metal removal 45.6 for de coked catalyst samples while NaOH gave 35% and citric acid gave 31.9 % The oxidized leaching agent was the most efficient leaching solvent to facilitate the metal removal, and the rejuvenated catalyst was characterized by the unchanged crystalline phase The rejuvenated catalyst was applied for hydrodesulfurization (HDS) of vacuum gas oil as a feedstock, under different hydrogen pressure 20-80 bar in order to compare its HDS activity

  17. Hydrodewaxing with mixed zeolite catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chester, A.W.; McHale, W.D.; Yen, J.H.

    1986-03-11

    A process is described for catalytically dewaxing a hydrocarbon lubricating oil feedstock comprising contacting the feedstock with a dewaxing catalyst, the dewaxing catalyst comprising, in combination: (a) a zeolite catalyst having a Constraint Index not less than 1, (b) an acidic catalytic material selected from the group consisting of Mordenite, TEA Mordenite, Dealuminized Y, Ultrastable Y, Rare Earth Y, amorphous silica-alumina chlorinated alumina, ZSM-4 and ZSM-20, and (c) a hydrogenation component, and recovering a dewaxed product. A process is also described for catalytically dewaxing a hydrocarbon lubricating oil feedstock comprising contacting the feedstock with a dewaxing catalyst, the dewaxing catalyst comprising, in combinations: (a) a first zeolite catalyst selected from the group consisting of ZSM-5, ZMS-11, ZSM-12, ZSM-22, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48, TMA Offretite and Erionite, (b) a second catalyst selected from the group consisting of ZSM-12, ZSM-22, ZSM-38 and ZSM-48, the second zeolite catalyst being different from the first zeolite catalyst, and (c) a hydrogenation component, and recovering a dewaxed product.

  18. Theoretical predictions of platinum-rhodium bimetallic catalysts

    International Nuclear Information System (INIS)

    After a general introduction to supported bimetallic catalysts and automobile catalytic converters (supports, base metal promoters, noble metals, deterioration of 3-way catalysts, current/future technology), a paper is presented for surface segregation in bimetallic catalysts: The catalytic properties are influenced by the structure of the cluster surface. Two methods are described to treat this problem, from the demanding corrected effective medium (CEM) theory (a non-self-consistent density functional based method) and the simple method of surface modified pair potentials. Predictions are compared with experiment for the heat of formation in RhxPt1-x alloys and for surface segregation in Rh0.9Pt0.1(111). Results on shape, site composition, surface micromixing are shown for 201 atom clusters (dispersion of 0.6) and RhxPt1-x(111). The CEM calculated cohesive energy of Rh is slightly smaller than for Pt, but the surface energy of Rh is larger: the driving force for surface segregation is the relative surface energies, not the relative cohesive energies. One can predict surface energy differences by accounting for the variation of the bond energy with coordination. Recommendations for the development of improved automobile exhaust catalysts are given. The Monte Carlo bimetallic simulation program is described

  19. Carbon Nanotubes and Other Nanostructures as Support Material for Nanoparticulate Noble-Metal Catalysts in Fuel Cells

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul; Veltzé, Sune; Skou, Eivind Morten

    platinum-alloy catalysts in the electrodes are required. To maximize the utilization of the noble metal it is frequently deposited as nanoparticles (1-5 nm) on a stabilizing support of carbon black. Carbon black provides good anchoring of the catalyst particles, but is prone to severe destructive oxidation...... fuel-cell electrodes. However, the low concentration of structural defects also poses challenges with regard to anchoring of the catalyst particles on the CNT surface. Thus, activation treatments introducing surface functional groups may be necessary. Also, the surface properties are responsible for...

  20. Carbon nanotubes and other nanostructures as support material for nanoparticulate noble-metal catalysts in fuel cells

    DEFF Research Database (Denmark)

    Veltzé, Sune; Larsen, Mikkel Juul; Elina, Yli-Rantala;

    platinum-alloy catalysts in the electrodes are required. To maximize the utilization of the noble metal it is frequently deposited as nanoparticles (1–5 nm) on a stabilizing support of carbon black. Carbon black provides good anchoring of the catalyst particles, but is prone to severe destructive oxidation...... fuel-cell electrodes. However, the low concentration of structural defects also poses challenges with regard to anchoring of the catalyst particles on the CNT surface. Thus, activation treatments introducing surface functional groups may be necessary. Also, the surface properties are responsible for...

  1. Activity and Stability of Nanoscale Oxygen Reduction Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Shao-Horn, Yang

    2015-07-28

    Design of highly active and stable nanoscale catalysts for electro-oxidation of small organic molecules is of great importance to the development of efficient fuel cells. The amount and instability of Pt-based catalysts in the cathode limits the cost, efficiency and lifetime of proton exchange membrane fuel cells. We developed a microscopic understanding of the factors governing activity and stability in Pt and PtM alloys. Experimental efforts were focused on probing the size and shape dependence of ORR activity of Pt-based nanoparticles supported on carbon nanotubes. A microscopic understanding of the activity was achieved by correlating voltammetry and rotating ring disk electrodes to surface atomic and electronic structures, which were elucidated predominantly by high-resolution transmission electron microscopy (HRTEM), Scanning transmission electron microscopy energy dispersive X-ray Spectroscopy (STEM-EDS) and synchrotron X-ray absorption spectroscopy (XAS).

  2. DEHYDROGENATION CATALYST FOR PRODUCTION OF MTBE

    Science.gov (United States)

    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...

  3. Deactivation-resistant catalyst for selective catalyst reduction of NOx

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a catalyst for selective catalytic reduction of NOx in alkali metal containing flue gas using ammonia as reductant, the catalyst comprising a surface with catalytically active sites, wherein the surface is at least partly coated with a coating comprising at least...

  4. A novel TiO2 nanofiber supported PdAg catalyst for methanol electro-oxidation

    International Nuclear Information System (INIS)

    A novel PdAg/TiO2 nanofiber electrocatalyst for methanol oxidation was fabricated by using TiO2 nanofiber as support. The structural and electrochemical properties of the PdAg/TiO2 nanofiber catalyst were characterized by XRD (X-ray diffraction), TEM (the transmission electron microscopy) and electrochemical analysis. The experiment results showed that the large surface area and porous structure of TiO2 nanofiber were preferable to the dispersion of nanosized PdAg alloy on the surface of TiO2 nanofiber support. The electrocatalytic activity for methanol oxidation of the PdAg/TiO2 nanofiber catalyst has shown promising electrocatalytic and anti-poisoning capabilities. The methanol oxidation mechanism of the PdAg/TiO2 nanofiber catalyst was mainly resulted from the photocatalytic function of the composite TiO2 material that had high catalytic activity without UV light illumination. The PdAg/TiO2 catalyst might become a promising candidate for direct methanol fuel cell. - Highlights: • Novel non-Pt catalyst of PdAg/TiO2 nanofiber for methanol oxidation is fabricated. • PdAg alloy is dispersed uniformly on the surface of TiO2 nanofiber support. • The novel catalyst shows promising electrocatalytic activity and anti-poisoning ability. • The methanol oxidation mechanism of the catalyst results from photocatalytic mechanism of TiO2

  5. Novel Reforming Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Technique for predicting the thermal expansion coefficients of cryogenic metallic alloys

    Science.gov (United States)

    Clark, A. F.

    1969-01-01

    Series of measurements on the thermal expansion coefficients of several aerospace alloys and standard materials establish relationships between related alloys that would aid in predicting their thermal expansion reliability. Thermal expansion data are also necessary for the reduction of electrical resistivity measurements of those same materials.

  7. Room-temperature synthesis and electrocatalysis of carbon nanotubes supported palladium–iron alloy nanoparticles

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNTs) supported palladium–iron bimetallic nanoparticles (Pd–Fe/CNTs) catalyst is synthesized using palladium hexacyanoferrate (PdHCF) as reaction precursor. In this method, the negatively charged PdHCF nanoparticles self-assemble on the positively charged polydiallyldimethylammonium chloride (PDDA) functionalized CNTs through electrostatic interaction, and then are reduced to Pd–Fe alloy nanoparticles by sodium borohydride. The physicochemical properties of Pd–Fe/CNTs are investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). These structural analyses reveal that the Pd–Fe/CNTs catalyst possesses the high alloying degree and the small particle size. Electrochemical measurements show that the eletrocatalytic activity of the Pd–Fe/MWCNTs catalyst for the methanol oxidation is better than that of the Pd/CNTs catalyst, which originates from the synergistic effect between Pd atom and Fe atom

  8. In-situ characterization of heterogeneous catalysts

    CERN Document Server

    Rodriguez, Jose A; Chupas, Peter J

    2013-01-01

    Helps researchers develop new catalysts for sustainable fuel and chemical production Reviewing the latest developments in the field, this book explores the in-situ characterization of heterogeneous catalysts, enabling readers to take full advantage of the sophisticated techniques used to study heterogeneous catalysts and reaction mechanisms. In using these techniques, readers can learn to improve the selectivity and the performance of catalysts and how to prepare catalysts as efficiently as possible, with minimum waste. In-situ Characterization of Heterogeneous Catalysts feat

  9. Research Report: HIV/AIDS

    Science.gov (United States)

    ... Reports » HIV/AIDS » Letter from the Director HIV/AIDS Email Facebook Twitter Letter from the Director Human ... the virus that causes acquired immune deficiency syndrome (AIDS) — has been with us for three decades now. ...

  10. HIV/AIDS and Alcohol

    Science.gov (United States)

    ... Psychiatric Disorders Other Substance Abuse HIV/AIDS HIV/AIDS Human immunodeficiency virus (HIV) targets the body’s immune ... and often leads to acquired immune deficiency syndrome (AIDS). Each year in the United States, between 55, ...

  11. HIV, AIDS, and the Future

    Science.gov (United States)

    Skip Navigation Bar Home Current Issue Past Issues HIV / AIDS HIV, AIDS, and the Future Past Issues / Summer 2009 ... turn Javascript on. Photo: The NAMES Project Foundation HIV and AIDS are a global catastrophe. While advances ...

  12. HIV/AIDS: Women's Health

    Science.gov (United States)

    ... Hospitalization and Palliative Care Friends & Family Dating and Marriage Family Planning Mixed-Status Couples Discrimination Legal Issues ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS ...

  13. What Is HIV/AIDS?

    Science.gov (United States)

    ... Hospitalization and Palliative Care Friends & Family Dating and Marriage Family Planning Mixed-Status Couples Discrimination Legal Issues ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS ...

  14. HIV/AIDS and Vaccines

    Science.gov (United States)

    ... Hospitalization and Palliative Care Friends & Family Dating and Marriage Family Planning Mixed-Status Couples Discrimination Legal Issues ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS ...

  15. HIV / AIDS: An Unequal Burden

    Science.gov (United States)

    ... Navigation Bar Home Current Issue Past Issues HIV / AIDS HIV / AIDS: An Unequal Burden Past Issues / Summer 2009 Table ... Victoria Cargill talks to students about HIV and AIDS at the opening of a National Library of ...

  16. High-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles for phenol hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chao [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Yang, Xu [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Yang, Hui; Huang, Peiyan; Song, Huiyu [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China); Liao, Shijun, E-mail: chsjliao@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province and The Key Laboratory for New Energy of Guangdong Universities, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou (China)

    2014-10-01

    Graphical abstract: The addition of Ru could significantly improve the performance of the mesoporous silica nanoparticles supported PdRu/MSN catalyst, which showed over 5 times higher mass activity than the mono-Pd/MSN towards the liquid-phase hydrogenation of phenol. The improved dispersion and the electronic interaction contributed to the enhanced catalytic activity for the catalyst towards phenol hydrogenation. - Highlights: • PdRu bimetal catalyst supported on mesoporous silica nanoparticles was prepared. • The average sizeof PdRu alloy is smaller than that of mono-Pd. • The addition of Ru to Pd modulates the electronic properties between Pd and Ru. • PdRu/MSN catalyst shows superior activity on phenol hydrogenation than Pd/MSN. • PdRu/MSN catalyst shows good selectivity for cyclohexanol to some extent. - Abstract: A high-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles (MSN), PdRu/MSN, was prepared by a facile impregnation–hydrogen reduction method. It was found that PdRu/MSN showed 5 times higher activity than that of Pd/MSN towards the liquid-phase hydrogenation of phenol. The catalysts were characterized comprehensively by multiple techniques, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen temperature program reduction (TPR). It was revealed that adding Ru could effectively improve the Pd dispersion and promote the electronic interaction between the Pd and Ru, both of which contribute to enhancing the catalytic activity.

  17. High-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles for phenol hydrogenation

    International Nuclear Information System (INIS)

    Graphical abstract: The addition of Ru could significantly improve the performance of the mesoporous silica nanoparticles supported PdRu/MSN catalyst, which showed over 5 times higher mass activity than the mono-Pd/MSN towards the liquid-phase hydrogenation of phenol. The improved dispersion and the electronic interaction contributed to the enhanced catalytic activity for the catalyst towards phenol hydrogenation. - Highlights: • PdRu bimetal catalyst supported on mesoporous silica nanoparticles was prepared. • The average sizeof PdRu alloy is smaller than that of mono-Pd. • The addition of Ru to Pd modulates the electronic properties between Pd and Ru. • PdRu/MSN catalyst shows superior activity on phenol hydrogenation than Pd/MSN. • PdRu/MSN catalyst shows good selectivity for cyclohexanol to some extent. - Abstract: A high-performance PdRu bimetallic catalyst supported on mesoporous silica nanoparticles (MSN), PdRu/MSN, was prepared by a facile impregnation–hydrogen reduction method. It was found that PdRu/MSN showed 5 times higher activity than that of Pd/MSN towards the liquid-phase hydrogenation of phenol. The catalysts were characterized comprehensively by multiple techniques, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and hydrogen temperature program reduction (TPR). It was revealed that adding Ru could effectively improve the Pd dispersion and promote the electronic interaction between the Pd and Ru, both of which contribute to enhancing the catalytic activity

  18. Aid Supplies Over Time

    DEFF Research Database (Denmark)

    Jones, Edward Samuel

    2015-01-01

    What determines how much foreign aid donors provide? Existing answers to this question point to a complex range of influences. However, the tasks of distinguishing between long- and short-run factors, as well as differences between donors, have not been adequately addressed. Taking advantage of...... data spanning nearly 50 years, this paper uses panel cointegration techniques to consider these issues. The analysis provides clear evidence for heterogeneity both between donors and over time, bandwagon effects, and a growing influence of security considerations in aid provision. Domestic...... macroeconomic shocks have a moderate but delayed effect on aid disbursements....

  19. Aid and Growth

    DEFF Research Database (Denmark)

    Tarp, Finn; Mekasha, Tseday Jemaneh

    2013-01-01

    Recent litterature in the meta-analysis category where results from a range of studies are brought together throws doubt on the ability of foreign aid to foster economic growth and development. This article assesses what meta-analysis has to contribute to the litterature on the effectiveness of...... foreign aid in terms of growth impact. We re-examine key hypotheses, and find that the effect of aid on growth is positive and statistically significant. This significant effect is genuine, and not an artefact of publication selection. We also show why our results differ from those published elsewhere....

  20. Aid and development

    DEFF Research Database (Denmark)

    Tarp, Finn

    2006-01-01

    Foreign aid looms large in the public discourse; and international development assistance remains squarely on most policy agendas concerned with growth, poverty and inequality in Africa and elsewhere in the developing world. The present review takes a retrospective look at how foreign aid has...... been effective in furthering economic growth and development is discussed in some detail. I add perspective and identify some critical unresolved issues. I finally turn to the current development debate and discuss some key concerns, I believe should be kept in mind in formulating any agenda for aid in...

  1. Aid and Growth

    DEFF Research Database (Denmark)

    Mekasha, Tseday Jemaneh; Tarp, Finn

    Some recent literature in the meta-analysis category where results from a range of studies are brought together throws doubt on the ability of foreign aid to foster economic growth and development. This paper assesses what meta-analysis has to say about the effectiveness of foreign aid in terms of...... the growth impact. We re-examine key hypotheses, and find that the effect of aid on growth is positive and statistically significant. This significant effect is genuine, and not an artefact of publication selection. We also show why our results differ from those published elsewhere....

  2. Pulmonary complications of AIDS: radiologic features. [AIDS

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B.A.; Pomeranz, S.; Rabinowitz, J.G.; Rosen, M.J.; Train, J.S.; Norton, K.I.; Mendelson, D.S.

    1984-07-01

    Fifty-two patients with pulmonary complications of acquired immunodeficiency syndrome (AIDS) were studied over a 3-year period. The vast majority of the patients were homosexual; however, a significant number were intravenous drug abusers. Thirteen different organisms were noted, of which Pneumocystis carinii was by far the most common. Five patients had neoplasia. Most patients had initial abnormal chest films; however, eight patients subsequently shown to have Pneumocystis carinii pneumonia had normal chest films. A significant overlap in chest radiographic findings was noted among patients with different or multiple organisms. Lung biopsy should be an early consideration for all patients with a clinical history consistent with the pulmonary complications of AIDS. Of the 52 patients, 41 had died by the time this report was completed.

  3. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    specifications. However, to take advantage of the automated analysis of Alloy, the model-oriented VDM specifications must be translated into a constraint-based Alloy specifications. We describe how a sub- set of VDM can be translated into Alloy and how assertions can be expressed in VDM and checked by the Alloy...

  4. Startup procedure for reforming catalysts

    Energy Technology Data Exchange (ETDEWEB)

    McHale, W.D.; Schoennagel, H.J.

    1984-08-14

    Process for reforming a hydrocarbon charge under reforming conditions in a reforming zone containing a sulfur-sensitive metal containing reforming catalyst wherein over-cracking of the charge stock and excessive temperature rise in the reforming zone is suppressed by pre-conditioning the catalyst, prior to contact with the charge, with a reformate of specified octane number and aromatics content.

  5. Doped palladium containing oxidation catalysts

    Science.gov (United States)

    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.

  6. Catalysts for low temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Catalyst design for biorefining.

    Science.gov (United States)

    Wilson, Karen; Lee, Adam F

    2016-02-28

    The quest for sustainable resources to meet the demands of a rapidly rising global population while mitigating the risks of rising CO2 emissions and associated climate change, represents a grand challenge for humanity. Biomass offers the most readily implemented and low-cost solution for sustainable transportation fuels, and the only non-petroleum route to organic molecules for the manufacture of bulk, fine and speciality chemicals and polymers. To be considered truly sustainable, biomass must be derived from resources which do not compete with agricultural land use for food production, or compromise the environment (e.g. via deforestation). Potential feedstocks include waste lignocellulosic or oil-based materials derived from plant or aquatic sources, with the so-called biorefinery concept offering the co-production of biofuels, platform chemicals and energy; analogous to today's petroleum refineries which deliver both high-volume/low-value (e.g. fuels and commodity chemicals) and low-volume/high-value (e.g. fine/speciality chemicals) products, thereby maximizing biomass valorization. This article addresses the challenges to catalytic biomass processing and highlights recent successes in the rational design of heterogeneous catalysts facilitated by advances in nanotechnology and the synthesis of templated porous materials, as well as the use of tailored catalyst surfaces to generate bifunctional solid acid/base materials or tune hydrophobicity. PMID:26755755

  8. Latent catalyst; Senzaisei shokubai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-01

    Epoxy resin, an important function material to support such main industries as electric and electronic devices, automobiles, civil engineering, and building construction, is demanded of development of single liquid type resin having excellent quick hardening performance and storage stability. This requirement comes from environmental problems with an intention of saving energies and reducing resin wastes. The Company, using freely its independent phase separation technology that controls molecular structure of catalysts, developed a latent catalyst having excellent storage stability and high-temperature quick hardening performance. Its major features may be summarized as follows: (1) excellent storage stability at room temperature keeping the product stable for 2.5 months or longer (2 days in conventional products); (2) quick hardening performance hardening the resin in seven seconds at 150 degrees C (equivalent to conventional products); and (3) excellent insulation performance of hardened resin at 140 degrees C of 7 times 10 {sup 13} (ohm) (center dot) cm (2 times 10 {sup 12} (ohm) (center dot) cm in conventional products) (translated by NEDO)

  9. Buying a Hearing Aid

    Science.gov (United States)

    ... Treatments & Cures Buying a Hearing Aid Cancer Treatment Scams Cancer Treatment Scams CURE-ious Bookmark Direct-to-Consumer Genetic Tests ... Money Privacy, Identity & Online Security Blog Video & Media Scam Alerts Get health and fitness updates by email ...

  10. The Aid Effectiveness Literature

    DEFF Research Database (Denmark)

    Doucouliagos, Hristos; Paldam, Martin

    The AEL consists of empirical macro studies of the effects of development aid. At the end of 2004 it had reached 97 studies of three families, which we have summarized in one study each using meta-analysis. Studies of the effect on investments show that they rise by 1/3 of the aid – the rest is...... crowded out by a fall in savings. Studies of the effect on growth show an insignificant positive effect. Studies of the effect on growth, conditional on something else, have till now shown weak results. The Dutch Disease effect of aid has been ignored. The best aggregate estimate is that since its start...... in the early 1960s aid has increased the standard of living in the poor countries by 20%....

  11. Performance Aided Design

    DEFF Research Database (Denmark)

    Parigi, Dario

    2014-01-01

    The paper present the methodologies and tools developed in the framework of Performance Aided Design (PAD), a term that indicates the shift in the use of Computer Aided Design (CAD) tools from a mere translation in a digital environment of the operations once carried on paper, to an evolving...... paradigm where the increasing integration of parametric tools and performative analysis is changing the way we learn and design. The term Performance Aided Architectural Design (PAD) is proposed at the Master of Science of Architecture and Design at Aalborg University, with the aim of extending a tectonic...... tradition of architecture with computational tools, preparing the basis for the creation of the figure of a modern master builder, sitting at the boundary of the disciplines of architecture and engineering. Performance Aided Design focuses on the role of performative analysis, embedded tectonics, and...

  12. HIV/AIDS

    Science.gov (United States)

    HIV stands for human immunodeficiency virus. It harms your immune system by destroying the white blood cells ... It is the final stage of infection with HIV. Not everyone with HIV develops AIDS. HIV most ...

  13. Aid and Development

    DEFF Research Database (Denmark)

    Tarp, Finn; Arndt, Channing; Jones, Edward Samuel

    inputs. We take as our point of departure a growth accounting analysis and review both intended and unintended effects of aid. Mozambique has benefited from sustained aid inflows in conflict, post-conflict and reconstruction periods. In each of these phases aid has made an unambiguous, positive...... sustained future growth, Mozambique will have to develop its capacity to maximise the benefits from its natural resources while ensuring at the same time the necessary framework is put in place to promote constructive integration in international markets...... contribution both enabling and supporting rapid growth since 1992. At the same time, the proliferation of donors and aid-supported interventions has burdened local administration and there is a distinct need to develop government accountability to its own citizens rather than donor agencies. In ensuring...

  14. World AIDS Day 1998.

    Science.gov (United States)

    1999-01-01

    Excerpts of speeches given at a public rally on World AIDS Day 1998 underscore the need to energize support for those living with HIV/AIDS, emphasize the importance of increasing public education efforts, and memorialize those lost to the disease. Reverend Pat Bumgardner stressed the need to educate children about practicing safe sex and the dangers of drug use. He also focused attention on AIDS as a worldwide crisis, with the 30 million people who have HIV or AIDS. Councilwoman Margarita Lopez spoke about achieving objectives and securing resources through activism. She also condemned New York City's Mayor for trying to hinder the rally. Anne Chelimsky, who did not speak at the rally but attended it, reflected on her new role as an activist, and on how the rally affected her. PMID:11367196

  15. AidData

    Data.gov (United States)

    US Agency for International Development — AidData is a research and innovation lab making information on development finance more accessible and actionable. Tracking more than $6 trillion dollars from 90+...

  16. HIV/AIDS

    Science.gov (United States)

    ... Casual contact, such as hugging Mosquitoes Participating in sports Touching items that were touched by a person ... 20 years. People with AIDS have had their immune system damaged by HIV. They are at very high ...

  17. House OK's Russian aid

    International Nuclear Information System (INIS)

    This article discusses the 2.5 Billion dollar aid package to Russia which House Appropriations Foreign Operations Subcommittee Chairman David Obey successfully defended on the House floor last June. Arizona Republican Jon Kyl offered an admendment that would cut 700 million from the package and was defeated with a 118 to 140 vote. The bill is currently in the hands of the Senate. The controversy over the bill and details concerning the aid package are discussed. The aid deal includes 250 million dollars for nuclear reactor safety and energy as well as environmental technical assistance, 655 million dollars to aid private sector development, and 704 million dollars for additional technical and economic assistance

  18. AIDS: A National Dilemma.

    Science.gov (United States)

    Issues in Science and Technology, 1987

    1987-01-01

    Contains excerpts from a special study on the AIDS epidemic by the Institute of Medicine and National Academy of Sciences. Presents an overview of the problem, outlines educational needs and public health measures, and identifies future research needs. (ML)

  19. HIV/AIDS

    Science.gov (United States)

    HIV stands for human immunodeficiency virus. It kills or damages the body's immune system cells. AIDS stands ... is the most advanced stage of infection with HIV. HIV most often spreads through unprotected sex with ...

  20. AIDS: the hidden enemy.

    Science.gov (United States)

    Tinker, J; Sabatier, R

    1987-01-01

    This article discusses the acquired immunodeficiency syndrome (AIDS) epidemic an its effect on developing countries, with emphasis on Africa. The AIDS death toll will be high in the US: 180,000 by 1991, but it will be in the millions in developing countries. In Africa, AIDS is mainly transmitted heterosexually, is as prevalent among women as among men, and is taking a serious toll among professional classes and young wage earners. The social costs of funerals has increased, and company clinics and sick pay funds have been overwhelmed. In Uganda, the epidemic adds to the state of psychological shock people have sufferred because of the civil war. Medical professionals have been hard-pressed to acquire equipment for testing blood for the virus, although there have been efforts to protect blood supplies through exhaustive testing. Endemic tuberculosis becomes an even more serious problem in developing countries, since AIDS lowers resistance to it. AIDS also effects many developing country children, usually through infected mothers, who can transmit AIDS through breast milk or during pregnancy of birth. This poses a dilemma for promoters of breastfeeding. It is also feared that innoculation of immunosuppressed children may be dangerous. The global picture suggests that Africa is hardest hit: seropositivity prevalence ranges from 0.7% of Congo blood donors to 33% of male donors in Lusaka Zambia. Brazil's cases are mainly homosexual, and in Asia the prevalence is mostly low, although there is a great potential danger in countries where prostitution and heroin addiction are prevalent. The only effective weapon against AIDS is education and blood testing to prevent spread. Despite good education programs in some countries, e.g. Rwanda, there is still widespread ignorance of how AIDS is spread. PMID:12314457

  1. Aid and Vulnerability

    OpenAIRE

    Andrea Filippo Presbitero

    2013-01-01

    Managing and identifying risks are a key challenge for Low Income Countries (LICs), which are extremely vulnerable to exogenous shocks. However, the use of risk management tools by developing countries is quite limited. The paper discusses in which ways aid could strengthen the capacity of LICs to deal with vulnerability to external shocks and to manage capital flows. We provide some novel empirical evidence on the potential role of aid as output stabilizer and shock absorber in recipient cou...

  2. Chagas' disease and AIDS

    OpenAIRE

    Vaidian, Anil K; Louis M Weiss; Tanowitz, Herbert B.

    2004-01-01

    Chagas' disease caused by Trypanosoma cruzi is an opportunistic infection in the setting of HIV/AIDS. Some individuals with HIV and chronic T. cruzi infection may experience a reactivation, which is most commonly manifested by meningoencephalitis. A reactivation myocarditis is the second most common manifestation. These presentations may be difficult to distinguish from toxoplasmosis in individuals with HIV/AIDS. The overlap of HIV and Trypanosoma cruzi infection occurs not only in endemic ar...

  3. [The liver and AIDS].

    Science.gov (United States)

    Rull, S; Sanchís, M J; Palacios, A; Anguiz, A; Colomina, J

    1992-02-01

    Hepatic disorders in AIDS are very common, although the injuries observed are usually non-specific. This is the reason why the real usefulness of hepatic biopsy in this patients is being currently discussed. In this work, such aspect and the hepatic injuries observed in patients with AIDS are discussed. Current indications for hepatic biopsy are summarized, as well as its later manipulation in order to obtain maximum profitability of it. PMID:1576316

  4. World AIDS Day 2004

    Institute of Scientific and Technical Information of China (English)

    CynthiaKirk; 刘保行

    2005-01-01

    December first was World AIDS Day. Last year, the campaign (运动;活动) centered on women and girls. They made up almost half of all people infected with the virus HIV that causes AIDS. And H1V was spreading faster among women than men in most areas of the world. These findings (发现) werefrom the yearly report by the United Nations and the World Health Organization, a UN agency

  5. Hearing aid adjustment

    DEFF Research Database (Denmark)

    Heinemann, Trine; Matthews, Ben; Raudaskoski, Pirkko Liisa

    2012-01-01

    to the interaction during hearing aid fitting. This report of a Danish pilot study describes two such problems. The first problem arises from the requirement that the audiologist needs to ‘translate’ the patient’s subjective hearing description for making technological decisions. The second problem...... is the way in which the hearing aid user’s implicit and often unrealistic expectations are handled. This kind of research has potential application for developing a model of best practices....

  6. The effect of Fe-Rh alloying on CO hydrogenation to C2+ oxygenates

    OpenAIRE

    Palomino, Robert M; Magee, Joseph W.; Llorca Piqué, Jordi; Senanayake, Sanjaya D.; White, Michael G.

    2015-01-01

    A combination of reactivity and structural studies using X-ray diffraction (XRD), pair distribution function (PDF), and transmission electron microscopy (TEM) was used to identify the active phases of Fe-modified Rh/TiO2 catalysts for the synthesis of ethanol and other C2+ oxygenates from CO hydrogenation. XRD and TEM confirm the existence of Fe-Rh alloys for catalyst with 1-7 wt% Fe and similar to 2 wt% Rh. Rietveld refinements show that FeRh alloy content increases with Fe loading up to sim...

  7. Characterization of FeCo based catalyst for ammonia decomposition. The effect of potassium oxide

    Directory of Open Access Journals (Sweden)

    Lendzion-Bieluń Zofia

    2014-12-01

    Full Text Available FeCo fused catalyst was obtained by fusing iron and cobalt oxides with an addition of calcium, aluminium, and potassium oxides (CaO, Al2O3, K2O. An additional amount of potassium oxide was inserted by wet impregnation. Chemical composition of the prepared catalysts was determined with an aid of the XRF method. On the basis of XRD analysis it was found that cobalt was built into the structure of magnetite and solid solution of CoFe2O4 was formed. An increase in potassium content develops surface area of the reduced form of the catalyst, number of adsorption sites for hydrogen, and the ammonia decomposition rate. The nitriding process of the catalyst slows down the ammonia decomposition.

  8. Oxidation of glycerol using gold-palladium alloy-supported nanocrystals.

    Science.gov (United States)

    Dimitratos, Nikolaos; Lopez-Sanchez, Jose Antonio; Anthonykutty, Jinto Manjaly; Brett, Gemma; Carley, Albert F; Tiruvalam, Ram Chandra; Herzing, Andrew A; Kiely, Christopher J; Knight, David W; Hutchings, Graham J

    2009-07-01

    The use of bio-renewable resources for the generation of materials and chemicals continues to attract significant research attention. Glycerol, a by-product from biodiesel manufacture, is a highly functionalised renewable raw material, and in this paper the oxidation of glycerol in the presence of base using supported gold, palladium and gold-palladium alloys is described and discussed. Two supports, TiO(2) and carbon, and two preparation methods, wet impregnation and sol-immobilisation, are compared and contrasted. For the monometallic catalysts prepared by impregnation similar activities are observed for Au and Pd, but the carbon-supported monometallic catalysts are more active than those on TiO(2). Glycerate is the major product and lesser amounts of tartronate, glycolate, oxalate and formate are observed, suggesting a sequential oxidation pathway. Combining the gold and palladium as supported alloy nanocrystals leads to a significant enhancement in catalyst activity and the TiO(2)-supported catalysts are significantly more active for the impregnated catalysts. The use of a sol-immobilisation preparation method as compared to impregnation leads to the highest activity alloy catalysts and the origins of these activity trends are discussed. PMID:19562125

  9. Alumina supported model Pd Ag catalysts: A combined STM, XPS, TPD and IRAS study

    Science.gov (United States)

    Khan, N. A.; Uhl, A.; Shaikhutdinov, S.; Freund, H.-J.

    2006-05-01

    The bimetallic Pd-Ag model catalysts were prepared by physical vapor deposition on thin alumina films. The morphology and structure of the Pd-Ag particles were studied by STM, XPS, and by TPD and IRAS of CO. The results showed the formation of true alloy particles with Ag segregated at the surface. The addition of Ag first suppresses the most strongly bonded CO on threefold hollow sites of Pd. With further increasing Ag coverage, only isolated Pd atoms surrounded by Ag atoms are likely present on the surface. The results on CO adsorption suggest that the model Pd-Ag system mimics the structure of the real Pd-Ag catalysts.

  10. Electroless synthesis of 3 nm wide alloy nanowires inside Tobacco mosaic virus

    International Nuclear Information System (INIS)

    We show that 3 nm wide cobalt–iron alloy nanowires can be synthesized by simple wet chemical electroless deposition inside tubular Tobacco mosaic virus particles. The method is based on adsorption of Pd(II) ions, formation of a Pd catalyst, and autocatalytic deposition of the alloy from dissolved metal salts, reduced by a borane compound. Extensive energy-filtering TEM investigations at the nanoscale revealed that the synthesized wires are alloys of Co, Fe, and Ni. We confirmed by high-resolution TEM that our alloy nanowires are at least partially crystalline, which is compatible with typical Co-rich alloys. Ni traces bestow higher stability, presumably against corrosion, as also known from bulk CoFe. Alloy nanowires, as small as the ones presented here, might be used for a variety of applications including high density data storage, imaging, sensing, and even drug delivery. (paper)

  11. Alloyed steel

    International Nuclear Information System (INIS)

    The composition and properties are listed of alloyed steel for use in the manufacture of steam generators, collectors, spacers, emergency tanks, and other components of nuclear power plants. The steel consists of 0.08 to 0.11% w.w. C, 0.6 to 1.4% w.w. Mn, 0.35 to 0.6% w.w. Mo, 0.02 to 0.07% w.w. Al, 0.17 to 0.37% w.w. Si, 1.7 to 2.7% w.w. Ni, 0.03 to 0.07% w.w. V, 0.005 to 0.012% w.w. N, and the rest is Fe. The said steel showed a sufficiently low transition temperature between brittle and tough structures, a greater depth of hardenability, and better weldability than similar steels. (B.S.)

  12. Final technical report. Bimetallic complexes as methanol oxidation catalysts

    Energy Technology Data Exchange (ETDEWEB)

    McElwee-White, Lisa

    2002-01-21

    Our work on the electrocatalyzed oxidation of methanol was initially motivated by the interest in methanol as an anodic reactant in fuel cells. The literature on electrochemical oxidation of alcohols can be roughly grouped into two sets: fuel cell studies and inorganic chemistry studies. Work on fuel cells primarily focuses on surface-catalyzed oxidation at bulk metal anodes, usually Pt or Pt/Ru alloys. In the surface science/electrochemistry approach to these studies, single molecule catalysts are generally not considered. In contrast, the inorganic community investigates the electrooxidation of alcohols in homogeneous systems. Ruthenium complexes have been the most common catalysts in these studies. The alcohol substrates are typically either secondary alcohols (e.g., isopropanol) such that the reaction stops after 2 e{sup -} oxidation to the aldehyde and 4 e{sup -} oxidation to the carboxylic acid can be observed. Methanol, which can also undergo 6 e{sup -} oxidation to CO{sub 2}, rarely appears in the homogeneous catalysis studies. Surface studies have shown that two types of metal centers with different functions result in more effective catalysts than a single metal; however, application of this concept to homogeneous systems has not been demonstrated. The major thrust of the work is to apply this insight from the surface studies to homogeneous catalysis. Even though homogeneous systems would not be appropriate models for active sites on Pt/Ru anodes, it is possible that heterobimetallic catalysts could also utilize two metal centers for different roles. Starting from that perspective, this work involves the preparation and investigation of heterobinuclear catalysts for the electrochemical oxidation of methanol.

  13. Hydrogenation of Furfural to Furfuryl Alcohol over Co-B Amorphous Catalysts Prepared by Chemical Reduction in Variable Media

    Institute of Scientific and Technical Information of China (English)

    LI, Hui; CHAI, Wei-Mei; LUO, Hong-Shan; LI, He-Xing

    2006-01-01

    Five Co-B amorphous alloy catalysts were prepared by chemical reduction in different media, including pure water and pure ethanol as well as the mixture of ethanol and water with variable ethanol content. Their catalytic properties were evaluated using liquid phase furfural hydrogenation to furfuryl alcohol as the probe reaction. It was found that the reaction media had no significant influence on either the amorphous structure of the Co-B catalyst or the electronic interaction between metallic Co and alloying B. This could successfully account for the fact that all the as-prepared Co-B catalysts exhibited almost the same selectivity to furfuryl alcohol and the same activity per surface area ( RSH ), which could be considered as the intrinsic activity, since the nature of active sites remained unchanged. However, the activity per gram of Co ( RmH ) of the as-prepared Co-B catalysts increased rapidly when the ethanol content in the water-ethanol mixture used as the reaction medium for catalyst preparation increased. This could be attributed to the rapid increase in the surface area possibly owing to the presence of more oxidized boron species which could serve as a support for dispersing the Co-B amorphous alloy particles.

  14. Hydrogen isotope enrichment by hydrophobic Pt-catalyst in Japan and Western countries

    International Nuclear Information System (INIS)

    The activities of the studies on hydrogen isotope separation by hydrophobic Pt-catalyst in Japan and the Western countries between 1970 and 1990 were reviewed. The R and D of tritium separation from heavy water or light water by the H2/H2O-isotopic exchange system with the aid of hydrophobic Pt-catalyst at the CRNL in Canada, the Mound Facility in the USA, the University of Karlsruhe in Germany and the Nuclear Center of Mol in Belgium were technically successful, but the construction of a commercial H2/H2O-isotopic exchange plant was abandoned or suspended because of political or budgetary problems. On the other hand, the Fugen heavy water upgrader using hydrogen isotope exchange by hydrophobic Pt-catalyst was constructed commercially and is treating on the average of about 10 m3 degraded heavy water (about 30%D) a year since 1986. In Canada, the major thrust of the development program of a new heavy water production process is directed at the CIRCE process. The catalyst used in this process is based on AECL's structured-type hydrophobic screen Pt-catalysts which are about three times more active than the corresponding random-type. Recent advances have allowed a fourfold reduction in Pt-metal loading without affecting catalyst performance. The objective of AECL is to develop the catalyst technology to allow commitment of a prototype CIRCE plant in 1994. (author)

  15. Ceramic catalyst materials

    Energy Technology Data Exchange (ETDEWEB)

    Sault, A.G.; Gardner, T.J. [Sandia National Laboratories, Albuquerque, NM (United States); Hanprasopwattanna, A.; Reardon, J.; Datye, A.K. [Univ. of New Mexico, Albuquerque, NM (United States)

    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.

  16. Electrodeposition of PdCu alloy and its application in methanol electro-oxidation

    International Nuclear Information System (INIS)

    This study demonstrates a simple electrodeposition method to fabricate the palladium–copper alloy on an ITO coated glass (PdCu/ITO) and its application in methanol electro-oxidation. Our approaches involve the co-reduction of Pd and Cu using triethanolamine (TEA) as a complexing agent in the electroplating bath and a Pd redox replacement of Cu on the surface of the as-prepared PdCu alloy. The phase structures, alloy compositions and morphologies of catalysts are determined by X-ray diffraction, energy dispersive spectrometer and scanning electron microscopy, respectively. X-ray diffraction shows that the particle size of PdCu deposits shrink when the alloy is deposited in a TEA-contained solution. The electrocatalytic properties of PdCu alloys and Pd redox replacement modified PdCu alloys for methanol oxidation have been investigated by cyclic voltammetry. The PdCu alloy with atomic ratio of 20.5% Cu exhibits higher catalytic activity toward methanol oxidation compared with a pure Pd catalyst. PdCu alloys with smaller particle sizes associated with TEA agent and the surface confined Pd replacement are found to have enhanced catalytic performance in the electro-oxidation of methanol.

  17. Electrodeposition of PdCu alloy and its application in methanol electro-oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Ming-Wei [Department of Chemistry, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Whang, Thou-Jen, E-mail: twhang@mail.ncku.edu.tw [Department of Chemistry, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

    2013-04-01

    This study demonstrates a simple electrodeposition method to fabricate the palladium–copper alloy on an ITO coated glass (PdCu/ITO) and its application in methanol electro-oxidation. Our approaches involve the co-reduction of Pd and Cu using triethanolamine (TEA) as a complexing agent in the electroplating bath and a Pd redox replacement of Cu on the surface of the as-prepared PdCu alloy. The phase structures, alloy compositions and morphologies of catalysts are determined by X-ray diffraction, energy dispersive spectrometer and scanning electron microscopy, respectively. X-ray diffraction shows that the particle size of PdCu deposits shrink when the alloy is deposited in a TEA-contained solution. The electrocatalytic properties of PdCu alloys and Pd redox replacement modified PdCu alloys for methanol oxidation have been investigated by cyclic voltammetry. The PdCu alloy with atomic ratio of 20.5% Cu exhibits higher catalytic activity toward methanol oxidation compared with a pure Pd catalyst. PdCu alloys with smaller particle sizes associated with TEA agent and the surface confined Pd replacement are found to have enhanced catalytic performance in the electro-oxidation of methanol.

  18. Atomic engineering of platinum alloy surfaces.

    Science.gov (United States)

    Li, Tong; Bagot, P A J; Marquis, E A; Edman Tsang, S C; Smith, G D W

    2013-09-01

    A major practical challenge in heterogeneous catalysis is to minimize the loading of expensive platinum group metals (PGMs) without degrading the overall catalytic efficiency. Gaining a thorough atomic-scale understanding of the chemical/structural changes occurring during catalyst manufacture/operation could potentially enable the design and production of "nano-engineered" catalysts, optimized for cost, stability and performance. In the present study, the oxidation behavior of a Pt-31 at% Pd alloy between 673-1073 K is investigated using atom probe tomography (APT). Over this range of temperatures, three markedly different chemical structures are observed near the surface of the alloy. At 673 K, the surface oxide formed is enriched with Pd, the concentration of which rises further following oxidation at 773 K. During oxidation at 873 K, a thick, stable oxide layer is formed on the surface with a stoichiometry of PdO, beneath which a Pd-depleted (Pt-rich) layer exists. Above 873 K, the surface composition switches to enrichment in Pt, with the Pt content increasing further with increasing oxidation temperature. This treatment suggests a route for tuning the surfaces of Pt-Pd nanoparticles to be either Pd-rich or Pt-rich, simply by adjusting the oxidation temperatures in order to form two different types of core-shell structures. In addition, comparison of the oxidation behavior of Pt-Pd with Pt-Rh and Pd-Rh alloys demonstrates markedly different trends under the same conditions for these three binary alloys. PMID:23276526

  19. Magnetically Recoverable Ruthenium Catalysts in Organic Synthesis

    OpenAIRE

    Dong Wang; Didier Astruc

    2014-01-01

    Magnetically recyclable catalysts with magnetic nanoparticles (MNPs) are becoming a major trend towards sustainable catalysts. In this area, recyclable supported ruthenium complexes and ruthenium nanoparticles occupy a key place and present great advantages compared to classic catalysts. In this micro-review, attention is focused on the fabrication of MNP-supported ruthenium catalysts and their catalytic applications in various organic syntheses.

  20. Impeded solid state reactions and transformations in ceramic catalysts supports and catalysts

    Directory of Open Access Journals (Sweden)

    Ernő E. Kiss

    2012-12-01

    Full Text Available Impeded chemical reactions and impeded polymorphous transformation in materials are discussed, as desired effects, for stabilization of ceramic catalyst supports and ceramic based catalysts. This paper gives a short overview about the possibilities of slowing down the aging processes in ceramic catalyst supports and catalysts. Special attention is given to alumina and titania based catalysts.

  1. AIDS ORPHANS GET SPECIAL VISITOR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chinese Premier Wen Jiabao visits AIDS orphans in Shangcai County,central China’s Henan Province,on November 30,a day before the 20th World AIDS Day. The region of Shangcai has the highest concentration of people living with HIV/AIDS in China. The Chinese Government has released a package of policies that offer people living with HIV/AIDS free medicine,health checks and consultations,as well as free schooling to AIDS orphans.

  2. Microstructure Evolution of a Multifunctional Titanium Alloy

    Science.gov (United States)

    Tian, Yu Xing; Hao, Yu Lin

    2016-03-01

    To optimize both mechanical and functional properties of multifunctional titanium alloys via grain refinement, an example of such alloys termed as Ti2448 is adopted to investigate its microstructure evolution and strain rate sensitivity by compression in the single β-phase field. The results show that flow stress and strain rate follow a bilinear relation, which is in sharp contrast with other metallic materials exhibiting a monotonic linearity. Below the critical strain of 1 s-1, the alloy has a normal strain rate sensitivity factor of 0.265. Above the critical value, its hardening rate is ultra-low with a factor of 0.03. Inspite of ultra-low hardening, the alloy is plastic stable under the tested conditions. With the aid of electron back-scattering diffraction and transmission electron microscopy analyses, microstructure evolution via several mechanisms such as dynamic recovery and recrystallization is evaluated by quantitative measurements of grain misorientation and its distribution, sub-grain formation, and localized grain refinement. These results are helpful to obtain the homogenous ultrafine-grained alloy by multi-step thermo-mechanical processing.

  3. The Science and Engineering of Durable Ultralow PGM Catalysts- 2012 DOE-EERE-FCT annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, Fernando H. [Los Alamos National Laboratory

    2012-07-16

    Minimizing the quantity of Pt group metals used in polymer membrane fuel cells (PEMFCs) is one of the remaining grand challenges for fuel cell commercialization. Tremendous progress has been achieved over the last two decades in decreasing the Pt loading required for efficient fuel cell performance. Unfortunately, the fluctuations in the price of Pt represent a substantial barrier to the economics of widespread fuel cell use. Durability and impurity tolerance are also challenges that are tightly coupled to fuel cell Pt electrode loading. Traditional approaches to decreasing the amount of Pt required for good performance include: (1) Increasing mass activity by decreasing Pt particle size by supporting on carbon; (2) Alloy formulation Pt-Co, Pt-Cr alloys to improve mass activity; (3) Increasing Pt utilization by optimization of electronic and ionic contact of the Pt particles; (4) Improving conductivity of the electronic and ionic conducting constituents of the membrane electrode assembly; and (5) Improving reactant to and product mass transport away from the electroactive sites. Recent novel approaches include the nanoengineering of core shell catalysts and Pt particles of unusual geometries such as nanowires/whiskers. The success of the aforementioned approaches has been great; however further advances using such approaches have been hampered by a lack of underlining scientific understanding of the catalyst activity, particle growth mechanisms, and optimization strategies for designing composite electrodes The objectives of this report are: (1) Development of durable, high mass activity Platinum Group Metal (PGM) cathode catalysts-enabling lower cost fuel cells; (2) Elucidation of the fundamental relationships between PGM catalyst shape, particle size and activity to help design better catalysts; (3) Optimization of the cathode electrode layer to maximize the performance of PGM catalysts-improving fuel cell performance and lowering cost; (4) Understanding the

  4. Early AIDS dementia complex

    International Nuclear Information System (INIS)

    A frequent complication of the acquired immunodeficiency syndrome (AIDS) is AIDS dementia complex (ADC). The authors evaluated seven patients with AIDS (aged 28-55 years, all male) for ADC by psychiatric evaluation, neuropsychological testing, CT scanning, and IMP-SPECT. Six of seven patients exhibited cognitive or behavioral abnormalities. Neuropsychological testing showed general deficits but no cases of explicit dementia. SPECT showed marked abnormalities in two cases: posterior temporal-parietal diminution of tracer uptake in one case (posterior/anterior=0.81) and marked right/left subcortical asymmetry (1.17) in the other. In three additional cases there was asymmetric tracer uptake in the subcortical and parietal regions. CT findings were normal in all seven cases. The authors conclude that functional imaging with the use of IMP-SPECT may be a useful method to follow ADC progression and response to therapy

  5. A constitution for AIDS.

    Science.gov (United States)

    Koshy, L M

    1996-01-15

    The Indian Health Organization projected the number of deaths per day due to AIDS by the year 2000 at 10,000. An interdisciplinary international conference was held in New Delhi to draft an international law governing the issues related to AIDS. Human freedom and public health policies are the most affected by this disease. In the absence of an international AIDS law, judicial verdicts set precedents and could have serious ramifications. A participant from the John Marshall Law School, Chicago, suggested that instead of making new laws, the existing ones from the colonial past should be repealed. This includes Section 377 of the Indian Penal Code, which provides criminal sanctions against those who indulge in unnatural relations with man, woman, or animal. Penalizing homosexuality will only perpetuate clandestine relations and spread the virus into their families. Another participant seconded this motion stating that even a sex worker must be protected from abuse and indignity. The National AIDS Control Organization responded to the criticism that the government had not utilized all the World Bank funds allocated for anti-AIDS projects. The trends of the epidemic were the most important indicators not just the numbers. In Manipur and Mizoram, infection was almost entirely due to injecting drug use. The Saheli project undertaken in the red-light areas of Bombay encompassed brothel owners and prostitutes, which could be replicated in other areas. Because existing government policies were focusing on prevention, there was no protection of an HIV-infected individual's privacy, one participant from Madras stated. The confidentiality issue was also echoed by a US participant. The New Delhi Declaration and Action Plan on HIV/AIDS was also discussed. It forbids discrimination in employment, education, housing, health care, social security, travel, and marital and reproductive rights. Providing sterile needles and ensuring the safety of the blood supply were other concerns

  6. Nano-Engineered Catalysts for Direct Methanol Fuel Cells

    Science.gov (United States)

    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

  7. Duplex steam reformer: alternate catalyst

    International Nuclear Information System (INIS)

    The manufacturing feasibility of a duplex steam reformer tube for potential use in a high temperature gas cooled reactor has been successfully demonstrated. This technique consists of explosively expanding the inner tube into the outer tube. To successfully achieve the desired 0 to 3 mil radial gap between the tubes it is necessary to perform the expansion in two steps with an intermediate anneal. A catalyst design that would have replaced the conventional Raschig rings with a metal supported catalyst has been evaluated and it has been concluded that further development and testing are needed before fabrication of a full scale prototype is warranted. Consequently, the immediate efforts are directed towards reevaluating the incentives for developing a catalyst and the probability of successfully developing a catalyst that could be used for steam reforming

  8. Alumina supported iridium catalysts - preparation

    International Nuclear Information System (INIS)

    This report describes the method employed in the preparation of alumina supported iridium catalysts, with metal contents between 30 and 40%, that will be used for hydrazine monopropellant decomposition. (author)

  9. Aid Supplies Over Time

    DEFF Research Database (Denmark)

    Jones, Edward Samuel

    The recent financial crisis has rekindled interest in the foreign aid supply behaviour of bilateral donors. Using the latest data covering the period 1960-2009, this paper examines how such behaviour is related to domestic factors. Based on a simple empirical model, a distinction is made between...... substantial heterogeneity between countries. There is also good evidence that donor behaviour continues to evolve over time. As such, past trends in aid supplies are unlikely to provide a good guide to those of the future....

  10. Hearing Aid Personalization

    DEFF Research Database (Denmark)

    Nielsen, Jens Brehm; Nielsen, Jakob; Jensen, Bjørn Sand;

    2013-01-01

    Modern digital hearing aids require and offer a great level of personalization. Today, this personalization is not performed based directly on what the user actually perceives, but on a hearing-care professional’s interpretation of what the user explains about what is perceived. In this paper, an...... interactive personalization system based on Gaussian process regression and active learning is proposed, which personalize the hearing aids based directly on what the user perceives. Preliminary results demonstrate a significant difference between a truly personalized setting obtained with the proposed system...

  11. Computer aided control engineering

    DEFF Research Database (Denmark)

    Szymkat, Maciej; Ravn, Ole

    1997-01-01

    Current developments in the field of Computer Aided Control Engineering (CACE) have a visible impact on the design methodologies and the structure of the software tools supporting them. Today control engineers has at their disposal libraries, packages or programming environments that may be speci......Current developments in the field of Computer Aided Control Engineering (CACE) have a visible impact on the design methodologies and the structure of the software tools supporting them. Today control engineers has at their disposal libraries, packages or programming environments that may...

  12. Aid and Development

    DEFF Research Database (Denmark)

    Tarp, Finn

    Foreign aid looms large in the public discourse; and international development assistance remains squarely on most policy agendas concerned with growth, poverty and inequality in Africa and elsewhere in the developing world. The present review takes a retrospective look at how foreign aid has...... been effective in furthering economic growth and development is discussed in some detail. I add perspective and identify some critical unresolved issues. I finally turn to the current development debate and discuss some key concerns, which I believe should be kept in mind in formulating any agenda for...

  13. Degradation of TATP, TNT, and RDX using mechanically alloyed metals

    Science.gov (United States)

    Clausen, Christian (Inventor); Geiger, Cherie (Inventor); Sigman, Michael (Inventor); Fidler, Rebecca (Inventor)

    2012-01-01

    Bimetallic alloys prepared in a ball milling process, such as iron nickel (FeNi), iron palladium (FePd), and magnesium palladium (MgPd) provide in situ catalyst system for remediating and degrading nitro explosive compounds. Specifically, munitions, such as, 2,4,6-trinitrotoluene (TNT), cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), nitrocellulose and nitroglycerine that have become contaminants in groundwater, soil, and other structures are treated on site to remediate explosive contamination.

  14. Irradiation effects of argon ion on a plate-type Raney nickel catalyst

    International Nuclear Information System (INIS)

    The present paper deals with restoration of the catalytic activity of Raney nickel deactivated by heat treatment (1), electrochemical oxidation (2) slow oxidation in water by dissolved oxygen (3) and quick oxidation in air (4). The plate-type Raney nickel catalyst used in this experiment is convenient for this particular ion-bombarding technique. The fine powder catalyst usually used could not be applied to this technique. The catalysts deactivated by the methods (2, 3) were activated by means of radio frequency diode sputtering system. An ordinary nickel plate and Raney nickel catalyst heated at high temperature (method 1) or burned in air (method 4) could not be activated by argon ion bombardment, because of the strong Ni-Ni and Ni-O bonds. The appearance of activity in Raney nickel catalyst generally results from amorphous nickel structure, when aluminum is leached from Ni-Al alloy. Activity restoration of catalyst by argon ion bombardment is satisfactly explained on the basis of the same reason. (author)

  15. Separately supported polymetallic reforming catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kresge, C. T.; Krishnamurthy, S.; McHale, W. D.

    1985-01-15

    There is provided, in accordance with the present invention, a catalyst composition made up of a mixture of two components, one component comprising a minor proportion of platinum and rhenium on a support and the second component comprising a minor proportion of iridium and rhenium on a separate support. A process for reforming a charge stock, such as naphtha, utilizing such catalyst is also provided.

  16. Characterization of rapidly and naturally quenched skeletal iron catalysts for FT synthesis

    Institute of Scientific and Technical Information of China (English)

    YAN Shi-run; QIAO Ming-hua; ZHU Yuan-long; FAN Kang-nian

    2004-01-01

    The slurry phase is a promising system for Fischer-Tropsch (FT) synthesis. Since the liquid medium efficiently removes the heat of reaction so that the steady-state reaction is easily achieved. High catalytic activity is maintained due to removal of waxy products from the catalyst surface by the action of solvent. In addition, CO-rich syngas from coal gasification can be directly used in FT synthesis which may increase the thermal efficiency of the indirect coal liquefaction. One of the important problems to be solved for slurry phase FT is the catalyst attrition and separation from wax residue. Fused iron and Raney iron were found to have high attrition resistance and easy to separate from wax in slurry phase FT synthesis, but their activity is relatively low. Amorphous alloys made by rapid quenching techniques have drawn increasing interest due to their superior mechanical,chemical and magnetic properties compared to the thermodynamically stable crystalline alloys of the same compositions. It is reported that rapidly quenched skeletal Ni catalyst showed higher catalytic activity than Raney Ni in selective hydrogenation of unsaturated organic functional groups.In this paper, Fe50Al50 (by weight) alloys with different quenching rates, rapid quenching (RQ) and natural quenching (NQ) were prepared for FT synthesis. The phase composition of alloys was characterized by XRD. The physical properties, thermal-stability and adsorption properties of skeletal Fe that was prepared by leaching aluminum of the corresponding alloy with aqueous solution of NaOH were also studied by BET, in situ XRD and H2- and CO-TPD. It is found from XRD patterns of the alloys that RQ Fe50Al50 is composed of orthorhombic phase, and NQ Fe50Al50 alloy is mainly composed of monoclinic phase. Meanwhile, diffraction peaks of the RQ alloy are seriously broadened. After leaching aluminum by aqueous solution of NaOH at the same conditions,skeletal Fe from the RQ alloy give the higher specific surface

  17. Characterization of Catalyst Materials for Production of Aerospace Fuels

    Science.gov (United States)

    Best, Lauren M.; De La Ree, Ana B.; Hepp, Aloysius F.

    2012-01-01

    Due to environmental, economic, and security issues, there is a greater need for cleaner alternative fuels. There will undoubtedly be a shift from crude oil to non-petroleum sources as a feedstock for aviation (and other transportation) fuels. Additionally, efforts are concentrated on reducing costs coupled with fuel production from non-conventional sources. One solution to this issue is Fischer-Tropsch gas-to-liquid technology. Fischer-Tropsch processing of synthesis gas (CO/H2) produces a complex product stream of paraffins, olefins, and oxygenated compounds such as alcohols and aldehydes. The Fisher-Tropsch process can produce a cleaner diesel oil fraction with a high cetane number (typically above 70) without any sulfur or aromatic compounds. This process is most commonly catalyzed by heterogeneous (in this case, silver and platinum) catalysts composed of cobalt supported on alumina or unsupported alloyed iron powders. Physisorption, chemisorptions, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) are described to better understand the potential performance of Fischer-Tropsch cobalt on alumina catalysts promoted with silver and platinum. The overall goal is to preferentially produce C8 to C18 paraffin compounds for use as aerospace fuels. Progress towards this goal will eventually be updated and achieved by a more thorough understanding of the characterization of catalyst materials. This work was supported by NASA s Subsonic Fixed Wing and In-situ Resource Utilization projects.

  18. Alloy Fabrication Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — At NETL’s Alloy Fabrication Facility in Albany, OR, researchers conduct DOE research projects to produce new alloys suited to a variety of applications, from gas...

  19. Synthesis and characterization of Fe–Ni/ɣ-Al2O3 egg-shell catalyst for H2 generation by ammonia decomposition

    DEFF Research Database (Denmark)

    Silva, Hugo José Lopes; Nielsen, Morten Godtfred; Fiordaliso, Elisabetta Maria;

    2015-01-01

    the active phase should match with the type of reaction. In this work, a novel synthesis route was developed for the preparation of a Fe–Ni/ɣ-Al2O3 egg-shell catalyst. Egg-shell is a preferred profile considering the highly endothermic nature of ammonia decomposition reaction. The high viscosity of......The Fe–Ni alloyed nanoparticles are a promising alternative to expensive ruthenium-based catalysts for a real-scale application of hydrogen generation by ammonia decomposition. In practical applications, millimeter-sized extrudates are used as catalyst supports, where the spatial distribution of....... The outer-shell region showed the presence of Fe and Ni alloyed nanoparticles with a size of approximately 5nm.. The egg-shell catalyst showed significant higher activity in ammonia decomposition by converting 3 times more ammonia to equilibrium conversion than either egg-white or catalyst with...

  20. Reaction products at the interface between Si3N4 and Ni-Cr alloys

    International Nuclear Information System (INIS)

    Interaction at the interface between Si3N4 and Ni-Cr alloys at 1125 C has been investigated. The internal nitridation of Ni-Cr alloys after annealing in contact with dense Si3N4 was found due to a high N2-pressure at the interface. The isothermal section of the Ni-Cr-Si system at 900 C was determined by using diffusion couples together with equilibrated alloys. The same isothermal section, as well as the activity of nitrogen in the Ni-Cr alloys was calculated with aid of the Thermo-Calc databank system. (orig.)

  1. Tracking the shape-dependent sintering of platinum–rhodium model catalysts under operando conditions

    OpenAIRE

    Hejral, Uta; Müller, Patrick; Balmes, Olivier; Pontoni, Diego; Stierle, Andreas

    2016-01-01

    Nanoparticle sintering during catalytic reactions is a major cause for catalyst deactivation. Understanding its atomic-scale processes and finding strategies to reduce it is of paramount scientific and economic interest. Here, we report on the composition-dependent three-dimensional restructuring of epitaxial platinum–rhodium alloy nanoparticles on alumina during carbon monoxide oxidation at 550 K and near-atmospheric pressures employing in situ high-energy grazing incidence x-ray diffraction...

  2. The innovation catalysts.

    Science.gov (United States)

    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

  3. Computer aided control engineering

    DEFF Research Database (Denmark)

    Szymkat, Maciej; Ravn, Ole

    Current developments in the field of Computer Aided Control Engineering (CACE) have a visible impact on the design methodologies and the structure of the software tools supporting them. Today control engineers has at their disposal libraries, packages or programming environments that may be...

  4. HIV/AIDS

    Science.gov (United States)

    ... health days Meetings and consultations 2014 Fact sheets Features Commentaries 2014 Multimedia Contacts HIV/AIDS Fact sheet Updated July 2016 Key facts HIV continues to be a major global public health issue, having claimed more than 35 million lives so far. In 2015, 1.1 (940 000– ...

  5. Computer aided magnet design

    International Nuclear Information System (INIS)

    In this paper the elements of a computer aided magnet design system is outlined. The methods of solving the field equations are briefly reviewed, followed by a survey of available codes. Particular examples of the use of RAL codes in solving 3D magnetic design problems are given. Future developments are discussed. (author)

  6. Computer aided safety analysis

    International Nuclear Information System (INIS)

    The document reproduces 20 selected papers from the 38 papers presented at the Technical Committee/Workshop on Computer Aided Safety Analysis organized by the IAEA in co-operation with the Institute of Atomic Energy in Otwock-Swierk, Poland on 25-29 May 1987. A separate abstract was prepared for each of these 20 technical papers. Refs, figs and tabs

  7. Hearing Aids Communication

    DEFF Research Database (Denmark)

    Globally, hearing loss is the second most frequent disability. About 80% of the persons affected by hearing loss do not use hearing aids. The goal of this edited volume is to present a theoretically founded, interdisciplinary approach geared at understanding and improving social interaction impac...

  8. AIDS, a development challenge.

    Science.gov (United States)

    1999-01-01

    During the Joint Conference of African Ministers of Planning and Finance, hosted by the UN Economic Commission for Africa in Addis Ababa on May 6-8, 1999, HIV/AIDS was highlighted as one of the major agendas for development planning. AIDS was considered to have a major impact on the household economy, the private sector, and at the macroeconomic level. Aside from the emotional impact of losing a loved one, the families of deceased HIV-infected individuals suffer an almost 50% reduction of income. This would consequently lead to cutting down on educational expenditures. On the other hand, national economies and private sectors suffer from a decreased purchasing power and loss of competitiveness in the global economy due to illiteracy. Furthermore, 50% of the national budget would be allocated for AIDS treatment, while private companies would experience a 7-20% decrease in profits as a result of high cost of medical treatment. In addition, the reduced pool of skilled labor and high expense of training would eventually bring about a decrease in high quality foreign investment. At the macroeconomic level, AIDS would result in a 1% reduction of gross domestic product growth per capita annually. It was suggested that strong political support, broad institutional participation and carefully selected program intervention, as well as openness about the disease and information dissemination on its cause and spread are deemed effective in the plan of eliminating the spread of the disease. PMID:12349447

  9. Leishmaniasis and AIDS coinfection*

    OpenAIRE

    Hozannah, Adriana; Santos, Monica; Chrusciak-Talhari, Anette; Talhari, Carolina

    2013-01-01

    Cutaneous leishmaniasis and HIV coinfection has been reported in Brazil since the initial description of AIDS in the country. We report an HIV-positive patient under antiretroviral treatment who presented with cutaneous leishmaniasis which was successfully treated with meglumine antimoniate.

  10. Range Scheduling Aid (RSA)

    Science.gov (United States)

    Logan, J. R.; Pulvermacher, M. K.

    1991-01-01

    Range Scheduling Aid (RSA) is presented in the form of the viewgraphs. The following subject areas are covered: satellite control network; current and new approaches to range scheduling; MITRE tasking; RSA features; RSA display; constraint based analytic capability; RSA architecture; and RSA benefits.

  11. Studying Aid: Some Methods

    NARCIS (Netherlands)

    D.R. Gasper (Des)

    2003-01-01

    textabstractINVESTIGATING IDEAS, IDEOLOGIES AND PRACTICES This paper presents some methods for trying to make sense of international aid and of its study.1 Some of the methods may be deemed ethnographic; the others are important partners to them, but rather different. In the course of discussing q

  12. AIDS Overspill to Everyman

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Xu Wenqing, national project officer of the UN International Children's Emergency Fund (UNICEF), recently issued a warning that the men/women ratio of HIV infection in China now stands at 5:5. This indicates that AiDS now threatens other than intravenous drug users, sex workers and hemophiliacs.

  13. Apartheid and AIDS.

    Science.gov (United States)

    Viljoen, A T

    1989-11-25

    To persuade South Africa to abolish its apartheid policy several measures have been taken by the international community, including economic sanctions. The harm done by sanctions to the South African economy is obvious. As economic activity has slowed down, unemployment, especially in the black community, has risen. For the unemployed poverty and hunger are harsh realities while for those lucky enough to have jobs income remains quite high. Prostitution has become a way of redistributing income and for many families it is the only way to avoid starvation. With prostitution, however, has come AIDS: it is estimated that HIV infection is doubling every 5-8 months. On 1 calculation 85% of sexually active blacks could be infected with HIV by 1996; most would proceed to AIDS and die, leaving millions of children without parents. Although economic sanctions have speeded up some measure of reform in South Africa they are now harming the very people they were intended to help. Furthermore insidious voices are already being heard saying the government should stop all reform processes and anti-AIDS campaigns and just "sit it out" for the next few years. A further consequence of an ailing economy is the unavailability of funding for those who wish to curb the spread of AIDS via educational and other programs. [Full text] PMID:2573792

  14. DIAPASON, supervision aid system

    International Nuclear Information System (INIS)

    Diapason, a supervision aid system, gives to the operator a synthetic representation of the process. It permits to predict the evolution of the process in order to realize an anticipated control; in incidental conditions, it permits a precocious detection and gives a default diagnostic. It comprises 3 modules used in a spent fuel reprocessing simulator. 9 refs

  15. Oesophageal candiasis in AIDS

    OpenAIRE

    Yadav, S. P. S.; Ranga, Rupender K.; Singh, Jagat; Yadav, Rohtas

    2003-01-01

    With the explosion in the number of AIDS patients, many of these are likely to consult to otolaryngologists the head & neck is a rather common site to be affected. Sometimes only oesophageal candidiasis is the presenting feature as in the present case which is being reported show typical radiological appearance. the differential diagnosis and treatment of nesophageal candidiasis is briefly discussed

  16. Aid Projects Benefit Xigaze

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Motivated by the thirdnational conference onwork in Tibet held by theCPC Central Committeeand the State Council meeting in July1994, Shanghai and Shandong provincedecided to provide aid to the Xigazearea from May 1995 onwards. Thefourth conference on work in Tibet heldin May 2001 again established that the

  17. More than First Aid

    Science.gov (United States)

    Schoessler, Sally

    2011-01-01

    The school nurse is an important member of the school team since school health services keep students in school, in the classroom, and ready to learn. Although school nurses are often seen as the people who deliver first aid at school, their role is much deeper and has such breadth that only a registered, professional nurse has the skill set to…

  18. Agglomeration and aid

    NARCIS (Netherlands)

    S. Brakman (Steven); J.H. Garretsen (Harry); J.G.M. van Marrewijk (Charles)

    2007-01-01

    textabstractA key issue in development economics is the explanation of core-periphery patterns around the world. Combining this issue with that of analyzing unilateral transfers (e.g. foreign aid) points in the direction of the use of New Economic Geography (NEG) models which, so far, has not been d

  19. First Aid Challenge

    Science.gov (United States)

    Roman, Harry T.

    2011-01-01

    This article describes a challenge wherein students will be asked to design a portable first aid kit that is normally carried in a recreational vehicle (RV), but can also be hand-carried or backpacked off road for distances of approximately 1-2 miles. This can be a very practical challenge for the students because it touches everyone. Everybody…

  20. First aid advisor

    Energy Technology Data Exchange (ETDEWEB)

    Saffer, S.I.; Weng, Wen-Chang [Texas A & M Univ., Commerce, TX (United States)

    1996-12-31

    A knowledge-based system (KBS), First Aid Advisor (FAA), is developed to provide a guidance for either a trained or untrained person to take some emergent actions to rescue the victim from life-threatening hazard or to prevent from causing serious problem before the Emergency Medical Service System (EMS) personnels arrive the scene. The First Aid Advisor will collect victim`s information by interacting with the user through a sequence of questions, analyze the victim`s problem, and give instructions step by step before offering a final advice. Since all the possible conditions are taken into consideration, it will guide the user to perform first aid from the most to the least urgent step for the victim. Furthermore, it will offer a suitable first aid advice for victim and eliminate the possibility of wrong actions done by trained person due to carelessness or nervousness. Offering advice to handle problems involving life-threatening conditions is the main objective of this system. In this paper, we will describe six major components of FAA and their respective tasks. Decision tables and dependency diagrams used in FAA implementation will also be described. System performance issues will conclude the paper.

  1. AIDS and associated malignancies

    Institute of Scientific and Technical Information of China (English)

    Charles; WOOD; William; HARRINGTON; Jr

    2005-01-01

    AIDS associated malignancies (ARL) is a major complication associated with AIDS patients upon immunosuppression.Chronically immunocompromised patients have a markedly increased risk of developing lymphoproliferative disease. In the era of potent antiretrovirals therapy (ARV), the malignant complications due to HIV- 1 infection have decreased in developed nations where ARV is administered, but still poses a major problem in developing countries where HIV- 1incidence is high and ARV is still not yet widely available. Even in ARV treated individuals there is a concern that the prolonged survival of many HIV- 1 carriers is likely to eventually result in an increased number of malignancies diagnosed.Malignancies that were found to have high incidence in HIV-infected individuals are Kaposi's sarcoma (KS), Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). The incidence of NHL has increased nearly 200 fold in HIV-positive patients, and accounts for a greater percentage of AIDS defining illness in the US and Europe since the advent of HAART therapy. These AIDS related lymphomas are distinct from their counterparts seen in HIV- 1 seronegative patients.For example nearly half of all cases of ARL are associated with the presence of a gamma herpesvirus, Epstein Barr virus (EBV) or human herpesvirus-8 (HHV-8)/Kaposi's sarcoma associated herpesvirus (KSHV). The pathogenesis of ARLs is complex. B-cell proliferation driven by chronic antigenemia resulting in the induction of polyclonal and ultimately monoclonal lymphoproliferation may occur in the setting of severe immunosuppression.

  2. Terbium base alloy

    International Nuclear Information System (INIS)

    Composition of terbium-5-7 % gadolinium alloy with high magnetostriction sensitivity (180x10-8 Oe) is suggested. The alloy is designed for usage under cryogenic temperature within 500-1500 Oe fields. Magnetostriction sensitivity of the suggested alloy is by 2-2.5 times higher, than that of well-known before one. 1 tab

  3. Synthesis of Pt-Ni alloy nanocrystals with high-index facets and enhanced electrocatalytic properties.

    Science.gov (United States)

    Xu, Xiling; Zhang, Xin; Sun, Hui; Yang, Ying; Dai, Xiaoping; Gao, Jinsen; Li, Xueyong; Zhang, Pengfang; Wang, Hong-Hui; Yu, Neng-Fei; Sun, Shi-Gang

    2014-11-10

    The shape-controlled synthesis of multicomponent metal nanocrystals (NCs) bounded by high-index facets (HIFs) is of significant importance in the design and synthesis of high-activity catalysts. We report herein the preparation of Pt-Ni alloy NCs by tuning their shape from concave-nanocubic (CNC) to nanocubic and hexoctahedral (HOH). Owing to the synergy of the HIFs and the electronic effect of the Pt-Ni alloy, the as-prepared CNC and HOH Pt-Ni alloy NCs exhibited excellent catalytic properties for the electrooxidation of methanol and formic acid, as well as for the oxygen reduction reaction (ORR). PMID:25195668

  4. AIDS: there's hope.

    Science.gov (United States)

    1993-06-01

    In 1993, 10 years after realizing that AIDS posed a threat to the future of mankind, social mobilization will improve the odds against AIDS. The objective is to create awareness about the virus, and to affect positive behavioral change through advocacy, communication, and grass-roots actions. The first goal is to change the societal attitude about the status of youth and women in order to understand that gender inequality fuels the pandemic. They are the most vulnerable groups, therefore their economic and social power must be improved. The Convention on the Rights of the Child and the Convention on the Elimination of All Forms of Discrimination against Women constitute a platform for broader action by governmental, nongovernmental, and religious institutions. In addition, these organizations need strong allies in society: 1) the media, which can communicate the importance of youth, women, and attitudes in the epidemic; 2) religious leaders, who can be powerful sources of advocacy for change in attitudes as well as support and care for AIDS-affected individuals and families; 3) policy makers, who can be crucial in changing existing policies and altering the allocation of government resources to youth and women; 4) human rights organizations, which play an important role in promoting the concept of health as a human right and for enhancing the understanding of AIDS in the context of discrimination and poverty; 5) the private sector, including commerce and industry, which can promote changes in attitude within the work force and AIDS prevention initiatives; and 6) parent-teacher groups and models for youth, who can educate them about socially acceptable and unacceptable behavior and can empower them to make responsible behavior choices. PMID:12179231

  5. [AIDS in Tanzania].

    Science.gov (United States)

    Barstad, S

    1993-04-20

    The World Health Organization has announced that within 3 years 10% of Tanzania's population of 26 million will be infected with the human immunodeficiency virus (HIV). But there is some faint hope in the research of Tanzanian traditional medicine. An almost 90-year-man, Waziri Mrisho, is credited with having treated AIDS patients successfully with herbs that strengthen the immune system. Margaret Nakamya was stricken by the symptoms of AIDs in March 1990. She was referred to Waziri and started using his herbs. 3 years later she weighs 49 kg compared to 40 kg before. The old man's son set up a little factory where he pulverizes herbs and sells them at the price he can command The 3 types of trees that the herbal medicine is taken from grow in the wild, but some have also been planted around the factory. Even if these herbs are effective, it will take years before the AIDS epidemic is over, when people have changed their lifestyles. The means of communication (TV, cinema, radio, telephone) are missing or inadequate. In the Kagera region, with 1.2 million inhabitants, 25% of pregnant women are HIV-infected and 65,000 children lost their parents to AIDS. There are 2000 children in Dar Es Salaam living in the streets. The Anglican St. Albans Church runs a center for street kids where they get meals 3 times a week. The nurse Ruth Nesje enlisted a Norwegian physician and homeopath in a research project involving 30 AIDS patients in Norway. The University in Bergen will do in vitro testing. One group of patients will receive both AZT and the herbs, another group will get only AZT, and the 3rd group will obtain only the herbs. The Norwegian Nursing Association, NORAD, and DANIDA also plan various projects in the Tanga region. PMID:8499187

  6. F-Alloy: An Alloy Based Model Transformation Language

    OpenAIRE

    Gammaitoni, Loïc; Kelsen, Pierre

    2015-01-01

    Model transformations are one of the core artifacts of a model-driven engineering approach. The relational logic language Alloy has been used in the past to verify properties of model transformations. In this paper we introduce the concept of functional Alloy modules. In essence a functional Alloy module can be viewed as an Alloy module representing a model transformation. We describe a sublanguage of Alloy called F-Alloy that allows the specification of functional Alloy modules. Module...

  7. Origin of low temperature deactivation of Ni5Ga3 nanoparticles as catalyst for methanol synthesis

    DEFF Research Database (Denmark)

    Gardini, Diego; Sharafutdinov, Irek; Damsgaard, Christian Danvad;

    In an effort to find alternative energy sources capable to compete with fossil fuels, methanol synthesis could represent a realistic solution to store “green” hydrogen produced from electrolysis or photo-induced water splitting. Recently, density functional theory (DFT) calculations [1] proposed Ni...... catalyst for methanol production. Synthesis, followed by deactivation and a series of regeneration steps at increasing temperature in pure H2 has been carried out in a fixed-bed reactor connected to a gas chromatography system. In each regeneration step, CH4 is generated and the activity of the catalyst is......-Ga alloys as active catalysts for methanol production from syngas mixtures and Ni-Ga nanoparticles supported on highly porous silica have been prepared using an incipient wetness impregnation technique from a solution of nickel and gallium nitrates [2]. Tests conducted in a fixed-bed reactor showed that the...

  8. Wireless Solar Water Splitting Using Silicon-Based Semiconductors and Earth-Abundant Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Reece, SY; Hamel, JA; Sung, K; Jarvi, TD; Esswein, AJ; Pijpers, JJH; Nocera, DG

    2011-11-03

    We describe the development of solar water-splitting cells comprising earth-abundant elements that operate in near-neutral pH conditions, both with and without connecting wires. The cells consist of a triple junction, amorphous silicon photovoltaic interfaced to hydrogen- and oxygen-evolving catalysts made from an alloy of earth-abundant metals and a cobalt|borate catalyst, respectively. The devices described here carry out the solar-driven water-splitting reaction at efficiencies of 4.7% for a wired configuration and 2.5% for a wireless configuration when illuminated with 1 sun (100 milliwatts per square centimeter) of air mass 1.5 simulated sunlight. Fuel-forming catalysts interfaced with light-harvesting semiconductors afford a pathway to direct solar-to-fuels conversion that captures many of the basic functional elements of a leaf.

  9. Palladium-tin catalysts for the direct synthesis of H₂O₂ with high selectivity.

    Science.gov (United States)

    Freakley, Simon J; He, Qian; Harrhy, Jonathan H; Lu, Li; Crole, David A; Morgan, David J; Ntainjua, Edwin N; Edwards, Jennifer K; Carley, Albert F; Borisevich, Albina Y; Kiely, Christopher J; Hutchings, Graham J

    2016-02-26

    The direct synthesis of hydrogen peroxide (H2O2) from H2 and O2 represents a potentially atom-efficient alternative to the current industrial indirect process. We show that the addition of tin to palladium catalysts coupled with an appropriate heat treatment cycle switches off the sequential hydrogenation and decomposition reactions, enabling selectivities of >95% toward H2O2. This effect arises from a tin oxide surface layer that encapsulates small Pd-rich particles while leaving larger Pd-Sn alloy particles exposed. We show that this effect is a general feature for oxide-supported Pd catalysts containing an appropriate second metal oxide component, and we set out the design principles for producing high-selectivity Pd-based catalysts for direct H2O2 production that do not contain gold. PMID:26917769

  10. Microstructural and auger microanalytical characterization of Cu-Hf and Cu-Ti catalysts.

    Science.gov (United States)

    Pisarek, M; Janik-Czachor, M

    2006-06-01

    Degradation processes occurring at the surface and in the bulk of Cu-based amorphous alloys during cathodic hydrogen charging were used for promoting the catalytic activity of such alloys. These processes modifying the structure, composition, and morphology of the substrate proved to be useful methods for transforming Cu-Hf and inactive Cu-Ti amorphous alloy precursors into active and durable catalysts. Indeed, their catalytic activity for dehydrogenation of 2-propanol increased up to a conversion level of approximately 60% at selectivities to acetone of about 99% for Cu-Ti and to conversion of approximately 90% at selectivities of approximately 95% for Cu-Hf. Previous attempts carried out by aging in air or hydrogen charging from the gas phase resulted in a maximum conversion level up to 15% for Cu-Hf and up to 3% for Cu-Ti. High resolution Auger spectroscopy allowed changes occurring during the activation process to be identified, namely, the formation of small Cu particles on the HfO2 surface and the formation of highly porous particles containing mostly Cu and some Ti and O (Cu-Ti-O) on a Cu-Ti substrate. Differences in the chemistry and structure of both catalysts are discussed, and the implications for catalytic function are considered. A probable configuration of active sites on the Cu-Ti-O/Ti-O-Cu catalyst for dehydrogenation of 2-propanol is proposed. PMID:17481359

  11. Preparation and characterization of silica-supported Ni/Pt catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Raab, C.; Lercher, J.A. (Universitaet Wien, Vienna (Austria)); Goodwin, J.G. Jr. (Univ. of Pittsburgh, PA (USA)); Shyu, J.Z. (Amoco Research Center, Naperville, IL (USA))

    1990-04-01

    The formation of a series of Ni/Pt catalysts was investigated by means of temperature programmed reduction (TPR) of the chloride precursor, hydrogen chemisorption, x-ray diffraction, scanning electron microscopy, XPS, and magnetic measurements. An alloy between Pt and Ni was formed. The minority constituent of the series of bimetallic catalysts was always found to be quantitatively alloyed or in close contact with the more abundant metal. For several samples, the stoichiometric NiPt compound was observed. With Ni-rich samples a nonstoichiometric alloy (rich in Ni) was concluded to exist. At all concentration levels the presence of Pt facilitated the reduction of Ni{sup 2+} significantly. Temperature-programmed reduction of the Ni/Pt catalyst with 50 mol% and higher concentrations of Pt did not differ from that of pure Pt. Based on XPS and magnetic measurements it is concluded that a constant fraction (approximately 10-15%) of Ni was highly dispersed and interacted strongly with the support. 30 refs.

  12. Foreign Aid and Consumption Smoothing; Evidence From Global Food Aid

    OpenAIRE

    Erwin Tiongson; Benedict J. Clements; Sanjeev Gupta

    2003-01-01

    Global food aid is considered a critical consumption smoothing mechanism in many countries. However, its record of stabilizing consumption has been mixed. This paper examines the cyclical properties of food aid with respect to food availability in recipient countries, with a view to assessing its impact on consumption in some 150 developing countries and transition economies, covering 1970 to 2000. The results show that global food aid has been allocated to countries most in need. Food aid ha...

  13. Low-temperature steam-reforming of ethanol over ZnO-supported Ni and Cu catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Homs, Narcis; Llorca, Jordi; De la Piscina, Pilar Ramirez [Departament de Quimica Inorganica, Universitat de Barcelona, C/Marti i Franques 1-11, 08028 Barcelona (Spain)

    2006-08-15

    ZnO-supported Ni and Cu as well as bimetallic Co-Ni and Co-Cu catalysts containing ca. 0.7wt% sodium promoter and prepared by the co-precipitation method were tested in the ethanol steam-reforming reaction at low temperature (523-723K), using a bioethanol-like mixture diluted in Ar. Monometallic ZnO-supported Cu or Ni samples do not exhibit good catalytic performance in the steam-reforming of ethanol for hydrogen production. Copper catalyst mainly dehydrogenates ethanol to acetaldehyde, whereas nickel catalyst favours ethanol decomposition. However, the addition of Ni to ZnO-supported cobalt has a positive effect both on the production of hydrogen at low temperature (<573K), and on catalyst stability. Evidence for alloy formation as well as mixed oxides at the microstructural level was found in the bimetallic systems after running the ethanol steam-reforming reaction by HRTEM-EELS. (author)

  14. Titanium and zirconium based wrought alloys and bulk metallic glasses for fluoride ion containing 11.5 M HNO3 medium

    International Nuclear Information System (INIS)

    Aqueous reprocessing of plutonium-rich mixed oxide fuels require fluoride as a catalyst in boiling nitric acid for an effective dissolution of the spent fuel. The corrosion behavior of the candidate dissolver materials zircaloy-4 (Zr-4) and commercial pure titanium (CP-Ti grade 2) in boiling 11.5 M HNO3 + 0.05 M NaF has been established. High corrosion rates were obtained for Zr- 4 and CP-Ti in nitric acid containing fluoride ions. Complexing the fluoride ions either with Al(NO3)3 or ZrO(NO3)2 aided in decreasing the corrosion rates of Zr-4 and CP-Ti. High corrosion resistance is claimed as one of the principal property of the amorphous alloy when compared to the crystalline alloy. Thus Ni60Nb40 and Ni60Nb30Ta10 amorphous ribbons were prepared and exposed in boiling 11.5 M HNO3 and 11.5 M HNO3 + 0.05 M NaF. In nitric acid these alloys did not show any sign of corrosion attack. XPS analysis confirmed that the passivity was due to the formation passive films of thickness ≈3 nm enriched with Nb2O5 and of ≈1.5 nm enriched with both Nb2O5 and Ta2O5 on the respective surfaces of the ribbons. In boiling 11.5 M HNO3 + 0.05 M NaF, severe corrosion attack was observed on Ni60Nb40 ribbon, due to the instability of the oxide/metal interface. The Ni60Nb30Ta10 amorphous ribbon exhibited corrosion resistance of at least an order of magnitude higher than that for Ni60Nb40 ribbon

  15. Visible Light Responsive Catalysts Using Quantum Dot-Modified Ti02 for Air and Water Purification

    Science.gov (United States)

    Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.; Hintze, paul; Clausen, Christian

    2012-01-01

    The method of photocatalysis utilizing titanium dioxide, TiO2, as the catalyst has been widely studied for trace contaminant control for both air and water applications because of its low energy consumption and use of a regenerable catalyst. Titanium dioxide requires ultraviolet light for activation due to its band gap energy of 3.2 eV. Traditionally, Hg-vapor fluorescent light sources are used in PCO reactors and are a setback for the technology for space application due to the possibility of Hg contamination. The development of a visible light responsive (VLR) TiO2-based catalyst could lead to the use of solar energy in the visible region (approx.45% of the solar spectrum lies in the visible region; > 400 nm) or highly efficient LEDs (with wavelengths > 400 nm) to make PCO approaches more efficient, economical, and safe. Though VLR catalyst development has been an active area of research for the past two decades, there are few commercially available VLR catalysts; those that are available still have poor activity in the visible region compared to that in the UV region. Thus, this study was aimed at the further development of VLR catalysts by a new method - coupling of quantum dots (QD) of a narrow band gap semiconductor (e.g., CdS, CdSe, PbS, ZnSe, etc.) to the TiO2 by two preparation methods: 1) photodeposition and 2) mechanical alloying using a high-speed ball mill. A library of catalysts was developed and screened for gas and aqueous phase applications, using ethanol and 4-chlorophenol as the target contaminants, respectively. Both target compounds are well studied in photocatalytic systems serve as model contaminants for this research. Synthesized catalysts were compared in terms of preparation method, type of quantum dots, and dosage of quantum dots.

  16. Henan Surveys Blood Donors to Aid AIDS Prevention

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Central China's Henan Province, one of the worst AIDS-hit provinces in the country, launched a sweeping survey in September of past blood donors to ascertain tile number of HIV-infected individuals to aid AIDS prevention and control work.

  17. Role of precursor alloy phases and intermediate oxides in the preparation of Raney and Urushibara iron

    International Nuclear Information System (INIS)

    57Fe Moessbauer spectroscopy and scanning electron microscopy measurements of precursor phases formed during catalyst preparation and of the catalysts, themselves, demonstrate that the preparation of Raney iron from iron aluminum alloys involves the formation of Fe (OH)2 and Fe3O4 as intermediate phases. The metallic Fe is formed from subsequent reduction of Fe3O4 by hydrogen generated by the oxidation of aluminum metal by hydroxide ions. Precursors to Urushibara iron U-Fe (III) are found to consist of Fe-Zn alloys when Zn is used as a reductant and of epitaxial deposits of Fe on aluminum when Al is the reductant. The material resulting from the reduction of the iron salt by aluminum is not a hydrogenation catalyst; the absence of catalytic activity is related to the absence of any alloying of the iron and aluminum. A consideration of the preparation of Raney iron, Urushibara iron, ammonia synthesis and Fischer-Tropsch catalysts leads to the conclusions that catalytic activity is highly correlated to the existence of intermediate mixed-crystals phases and the presence of intimate mixtures of at least two phases in the final catalyst. (orig.)

  18. Platinum- and platinum alloy-coated palladium and palladium alloy particles and uses thereof

    Science.gov (United States)

    Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir Branko

    2010-04-06

    The present invention relates to particle and nanoparticle composites useful as oxygen-reduction electrocatalysts. The particle composites are composed of a palladium or palladium-alloy particle or nanoparticle substrate coated with an atomic submonolayer, monolayer, bilayer, or trilayer of zerovalent platinum atoms. The invention also relates to a catalyst and a fuel cell containing the particle or nanoparticle composites of the invention. The invention additionally includes methods for oxygen reduction and production of electrical energy by using the particle and nanoparticle composites of the invention.

  19. Complex metallic alloys as new materials for additive manufacturing

    International Nuclear Information System (INIS)

    Additive manufacturing processes allow freeform fabrication of the physical representation of a three-dimensional computer-aided design (CAD) data model. This area has been expanding rapidly over the last 20 years. It includes several techniques such as selective laser sintering and stereolithography. The range of materials used today is quite restricted while there is a real demand for manufacturing lighter functional parts or parts with improved functional properties. In this article, we summarize recent work performed in this field, introducing new composite materials containing complex metallic alloys. These are mainly Al-based quasicrystalline alloys whose properties differ from those of conventional alloys. The use of these materials allows us to produce light-weight parts consisting of either metal–matrix composites or of polymer–matrix composites with improved properties. Functional parts using these alloys are now commercialized. (review)

  20. Electrodeposition of Compositionally Modulated Zinc-cobalt Alloy Multilayer Coatings

    Institute of Scientific and Technical Information of China (English)

    费敬银; 梁国正; 辛文利

    2005-01-01

    The effects of pulse parameters on the cobalt content, surface morphologies and grain size of Zn-Co alloy deposits were studied using a pulse plating technique with a square-wave current containing reverse pulse. Average current density and reverse anodic current density amongst the variables investigated have very strong effects on the cobalt content in the Zn-Co alloy deposits. Grain size, surface appearance and internal stress in the deposit were improved significantly by introducing the reverse current. Varieties of Zn-Co alloy compositionally modulated multilayer (CMM) coatings with large differences in cobalt contents for different sublayers were electrodeposited by designing corresponding waveforms using a computer-aided pulse plater and characterized in terms of surface morphologies. Cross-sectional morphologies of the Zn-Co alloy CMM coatings, examined using field emission gun scanning electron microscopy (FEGSEM), confirmed the layered structure.

  1. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub

    2012-06-05

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  2. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX

    2010-08-31

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  3. Single crystal studies of platinum alloys for oxygen reduction electrodes

    DEFF Research Database (Denmark)

    Ulrikkeholm, Elisabeth Therese

    In this thesis the discovery, characterization and testing of new catalysts for the oxygen reduction reaction (ORR) is investigated. Experiments on sputter cleaned, polycrystalline Pt5Y and Pt5Gd crystals have shown that these alloys are excelent candidates for catalysts for the ORR. To mimic the...... behavior of bulk single crystals, deposition of yttrium and gadolinium on a clean, annealed Pt(111) crystal were investigated in UHV. PtxY and PtxGd alloys terminated with a single atomic layer of platinum were formed after annealing to 500 °C in UHV. These alloys will be referred to as Y/Pt(111) and Gd.......89×1.89 structure, and the Gd/Pt(111) sample has formed a 1.90×1.90 structure compared to pure platinum. From the XPS measurements, it is most likely that alloys with the Pt5Y and Pt5Gd stoichiometry have been formed. The reactivity of the surfaces were probed using TPD. These measurements showed sharp desorption...

  4. Women and HIV/AIDS

    Science.gov (United States)

    ... About Us Contact Us Text size | Print | HIV/AIDS This information in Spanish ( en español ) The human ... HIV, is a sexually transmitted infection and causes acquired immunodeficiency syndrome, or AIDS. Today, about one in four Americans ...

  5. HIV / AIDS: An Unequal Burden

    Science.gov (United States)

    Skip Navigation Bar Home Current Issue Past Issues HIV / AIDS HIV / AIDS: An Unequal Burden Past Issues / Summer 2009 ... high-risk category, emphasizes Dr. Cargill. Photo: iStock HIV and Pregnancy Are there ways to help HIV- ...

  6. Different Styles of Hearing Aids

    Science.gov (United States)

    ... aids available and offer some cosmetic and listening advantages. Photo courtesy of Phonak Click for larger image ... in place. These aids offer cosmetic and listening advantages and are used typically for adults. Photo courtesy ...

  7. Ten Common First Aid Mistakes

    Science.gov (United States)

    ... for the Latest in Workplace Safety Ten Common First Aid Mistakes These days, there are countless resources to ... We’ve listed some of the most common first aid mistakes below, along with the correct response methods. ...

  8. Fischer-Tropsch Catalyst for Aviation Fuel Production

    Science.gov (United States)

    DeLaRee, Ana B.; Best, Lauren M.; Bradford, Robyn L.; Gonzalez-Arroyo, Richard; Hepp, Aloysius F.

    2012-01-01

    As the oil supply declines, there is a greater need for cleaner alternative fuels. There will undoubtedly be a shift from crude oil to nonpetroleum sources as a feedstock for aviation (and other transportation) fuels. The Fischer-Tropsch process uses a gas mixture of carbon monoxide and hydrogen which is converted into various liquid hydrocarbons; this versatile gas-to-liquid technology produces a complex product stream of paraffins, olefins, and oxygenated compounds such as alcohols and aldehydes. The Fischer-Tropsch process can produce a cleaner diesel oil fraction with a high cetane number (typically above 70) without any sulfur and aromatic compounds. It is most commonly catalyzed by cobalt supported on alumina, silica, or titania or unsupported alloyed iron powders. Cobalt is typically used more often than iron, in that cobalt is a longer-active catalyst, has lower water-gas shift activity, and lower yield of modified products. Promoters are valuable in improving Fischer-Tropsch catalyst as they can increase cobalt oxide dispersion, enhance the reduction of cobalt oxide to the active metal phase, stabilize a high metal surface area, and improve mechanical properties. Our goal is to build up the specificity of the Fischer-Tropsch catalyst while adding less-costly transition metals as promoters; the more common promoters used in Fischer-Tropsch synthesis are rhenium, platinum, and ruthenium. In this report we will describe our preliminary efforts to design and produce catalyst materials to achieve our goal of preferentially producing C8 to C18 paraffin compounds in the NASA Glenn Research Center Gas-To-Liquid processing plant. Efforts at NASA Glenn Research Center for producing green fuels using non-petroleum feedstocks support both the Sub-sonic Fixed Wing program of Fundamental Aeronautics and the In Situ Resource Utilization program of the Exploration Technology Development and Demonstration program.

  9. Determination of the catalyst circulation rate in a FCC cold flow pilot unit using nuclear techniques

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Valdemir A. dos, E-mail: valdemir.alexandre@pq.cnpq.br [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil). Centro de Ciencias e Tecnologia; Dantas, Carlos C.; Melo, Silvio B., E-mail: ccd@ufpe.br, E-mail: sbm@cin.ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Lima, Emerson A.O., E-mail: eal@poli.br [Universidade de Pernambuco (UPE), Recife, PE (Brazil). Escola Politecnica

    2013-07-01

    Nuclear techniques of gamma transmission and radioactive tracer were used to estimate the catalyst circulation rate in a cold flow pilot plant unit of Fluid Catalytic Cracking (FCC). Catalyst circulation rate in a FCC unit, allow to determine operating conditions of the exchange catalyst and inlet data for fluid dynamic simulation computational program. The pilot unit was fabricated obeying geometrical parameters provided by the Petrobras Research Center (CENPES), based on hot pilot units to existing in that center. The cold flow pilot unit has a transfer line, two separation vessels flash type, a return column, a riser and a regenerator. The vertical sections as riser, return column, regenerator column and transfer line are made of transparent material (glass). The two separation vessels have bases with tapered cylindrical shapes and are made of steel plates. The riser is divided into four sections of different diameters (0.005 m, 0.010 m, 0.018 m and 0.025 m) and rising upwards, to simulate the increasing flow rate caused by the increase of volume with the increase of the number of moles due to molecules breakage. The radioactive tracer used was the catalyst itself (intrinsic tracer) irradiated by neutron activation, yielding the radioisotope {sup 59}Fe. The velocity measurements were also obtained with aid of an electronic clock triggered by certain radiation levels across the two detectors. Besides estimates for the catalyst circulation rate was possible to identify the type of flow relative to the catalyst in return column. (author)

  10. Determination of the catalyst circulation rate in a FCC cold flow pilot unit using nuclear techniques

    International Nuclear Information System (INIS)

    Nuclear techniques of gamma transmission and radioactive tracer were used to estimate the catalyst circulation rate in a cold flow pilot plant unit of Fluid Catalytic Cracking (FCC). Catalyst circulation rate in a FCC unit, allow to determine operating conditions of the exchange catalyst and inlet data for fluid dynamic simulation computational program. The pilot unit was fabricated obeying geometrical parameters provided by the Petrobras Research Center (CENPES), based on hot pilot units to existing in that center. The cold flow pilot unit has a transfer line, two separation vessels flash type, a return column, a riser and a regenerator. The vertical sections as riser, return column, regenerator column and transfer line are made of transparent material (glass). The two separation vessels have bases with tapered cylindrical shapes and are made of steel plates. The riser is divided into four sections of different diameters (0.005 m, 0.010 m, 0.018 m and 0.025 m) and rising upwards, to simulate the increasing flow rate caused by the increase of volume with the increase of the number of moles due to molecules breakage. The radioactive tracer used was the catalyst itself (intrinsic tracer) irradiated by neutron activation, yielding the radioisotope 59Fe. The velocity measurements were also obtained with aid of an electronic clock triggered by certain radiation levels across the two detectors. Besides estimates for the catalyst circulation rate was possible to identify the type of flow relative to the catalyst in return column. (author)

  11. Biocompatibility of dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)

    2001-10-01

    Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

  12. Global NeuroAIDS roundtable

    OpenAIRE

    Joseph, J.; Achim, CL; Boivin, MJ; Brew, BJ; Clifford, DB; Colosi, DA; Ellis, RJ; Heaton, RK; Gallo-Diop, A; Grant, I; Kanmogne, GD; Kumar, M; Letendre, S; Marcotte, TD; Nath, A

    2013-01-01

    In May 2012, the Division of AIDS Research at the National Institute of Mental Health (NIMH) organized the "Global NeuroAIDS Roundtable" in conjunction with the 11th International Symposium on Neurovirology and the 2012 Conference on HIV in the Nervous System. The meeting was held in New York, NY, USA and brought together NIMH-funded investigators who are currently working on projects related to the neurological complications of AIDS (NeuroAIDS) in Africa, Asia, Eastern Europe, and Latin Amer...

  13. Aid allocation and fragile states

    OpenAIRE

    McGillivray, Mark

    2006-01-01

    This paper summarises research on aid allocation and effectiveness, highlighting the current findings of recent research on aid allocation to fragile states. Fragile states are defined by the donor community as those with either critically poor policies or poorly performing institutions, or both. The paper examines the research findings in the broader context of research and analysis on how aid should and is being allocated across all developing countries. Various aid allocation models and th...

  14. Cerebral toxoplasmosis in AIDS

    International Nuclear Information System (INIS)

    Since 1982 (Hauser and co-workers), literature has reported focal cerebral tissue charges in AIDS patients whose diagnosis was unclear at first but which could be identified finally as florid toxoplasmosis encephalitis by biopsy and autopsy. It was found that the value of otherwise reliable serological tests (KBR, Sabin-Feldmann tests, etc.) is questionable in patients with severely impaired or incompetent immune systems, and, in particular, that a negative or uncharacteristic test result may not preclude any opportunistic infection process. Furthermore, isolation of Toxoplasma gondii or specific antibodies from the cerebrospinal fluid will be successful in exceptional cases only. In patients with AIDS or lymphadenopathy syndrome, the differential diagnosis will have to include - first and foremost - reactivated toxoplasma infection (not newly acquired, as a rule) if central neurological symptoms occur. (orig.)

  15. Mutual aid fund commission

    CERN Multimedia

    Staff Association

    2011-01-01

    The composition of the Board of the Mutual Aid Fund for 2011 is as follows: President: Pascal Droux Vice-president: Connie Potter Treasurer: Louis Pereira Deputy treasurer: Barbara Brugger Secretary: Sonia Casenove Deputy secretary: Isabelle Mardirossian Members: Christopher David Thomas   Jean-Claude Vialis (GAC member)   Marie-Luce Falipou   Gunilla Santiard (Jean-Claude Vialis’s alternate) The role of the Fund is to provide financial help to members of personnel and beneficiaries of the Pension Fund who are in need of exceptional financial assistance. All requests are treated in the strictest confidence. Should you wish to apply for aid from the Fund, kindly contact any member of the Board as given above or Social Services, tel.74479 – 73867.

  16. How Do People Get AIDS?

    Science.gov (United States)

    ... a Friend Who Cuts? How Do People Get AIDS? KidsHealth > For Teens > How Do People Get AIDS? Print A A A Text Size en español ¿Cómo contrae alguien el SIDA? AIDS stands for acquired immunodeficiency syndrome , a disease that ...

  17. HIV/AIDS and Alcohol

    Science.gov (United States)

    ... Other Psychiatric Disorders Other Substance Abuse HIV/AIDS HIV/AIDS Human immunodeficiency virus (HIV) targets the body’s immune ... and abuse can contribute to the spread of HIV/AIDS and affect treatment for infected patients. Abusing alcohol ...

  18. AIDS: Dynamics and Rehabilitation Concerns.

    Science.gov (United States)

    Wong, Henry; And Others

    1988-01-01

    The epidemic of Acquired Immune Deficiency Syndrome (AIDS) confronts the rehabilitation professional with a number of concerns. This paper reviews literature on the diagnosis, epidemiological factors, psychosocial elements, medical intervention of AIDS, and rehabilitation issues involved in serving AIDS patients. (JDD)

  19. Synthesis and Electrochemical Evaluation of Carbon Supported Pt-Co Bimetallic Catalysts Prepared by Electroless Deposition and Modified Charge Enhanced Dry Impregnation

    Directory of Open Access Journals (Sweden)

    John Meynard M. Tengco

    2016-06-01

    Full Text Available Carbon-supported bimetallic Pt-Co cathode catalysts have been previously identified as higher activity alternatives to conventional Pt/C catalysts for fuel cells. In this work, a series of Pt-Co/C catalysts were synthesized using electroless deposition (ED of Pt on a Co/C catalyst prepared by modified charge enhanced dry impregnation. X-ray diffraction (XRD and scanning transmission electron microscopy (STEM characterization of the base catalyst showed highly dispersed particles. A basic ED bath containing PtCl62− as the Pt precursor, dimethylamine borane as reducing agent, and ethylenediamine as stabilizing agent successfully targeted deposition of Pt on Co particles. Simultaneous action of galvanic displacement and ED resulted in Pt-Co alloy formation observed in XRD and energy dispersive X-ray spectroscopy (XEDS mapping. In addition, fast deposition kinetics resulted in hollow shell Pt-Co alloy particles while particles with Pt-rich shell and Co-rich cores formed with controlled Pt deposition. Electrochemical evaluation of the Pt-Co/C catalysts showed lower active surface but much higher mass and surface activities for oxygen reduction reaction compared to a commercial Pt/C fuel cell catalyst.

  20. Computer aided product design

    DEFF Research Database (Denmark)

    Constantinou, Leonidas; Bagherpour, Khosrow; Gani, Rafiqul; Klein, J.A.; Wu, D.T.

    A general methodology for Computer Aided Product Design (CAPD) with specified property constraints which is capable of solving a large range of problems is presented. The methodology employs the group contribution approach, generates acyclic, cyclic and aromatic compounds of various degrees of......-liquid equilibria (LLE), solid-liquid equilibria (SLE) and gas solubility. Finally, a computer program based on the extended methodology has been developed and the results from five case studies highlighting various features of the methodology are presented....

  1. Transitional justice and aid

    OpenAIRE

    Hellsten, Sirkku K.

    2012-01-01

    This paper examines the current security-governance-development nexus, something that is often also discussed under the concept of transitional justice (TJ). The paper analyses how the ambiguous, evolving and expanding nature of the concept of TJ affects the planning, coordination, evaluation and assessment of aid given to conflict ridden, post-conflict or (post) authoritarian societies in order to strengthen their democracy. Special attention is paid to gender justice. Illustrations are draw...

  2. Pulmonary mycosis in AIDS

    International Nuclear Information System (INIS)

    We retrospectively reviewed our series of 35 pulmonary mycosis in patients with AIDS, observed from 1987 to 1999, to correlate the imaging and pathologic findings. We further evaluated the frequency of fungal pneumonia before and after the use of a highly active antiretroviral therapy (HAART). Early recognition of pulmonary mycosis is imperative in these patients and improved survival can be achieved with early CT detection and prompt institution of high-dose antifungal therapy

  3. Pulmonary mycosis in AIDS

    Energy Technology Data Exchange (ETDEWEB)

    Busi Rizzi, Elisa; Schinina, Vincenzo; Bellussi, Angelo; De Santis, Andrea; Mazzuoli, Giovanna; Giosue, Sandro; Bibbolino, Corrado

    2001-01-01

    We retrospectively reviewed our series of 35 pulmonary mycosis in patients with AIDS, observed from 1987 to 1999, to correlate the imaging and pathologic findings. We further evaluated the frequency of fungal pneumonia before and after the use of a highly active antiretroviral therapy (HAART). Early recognition of pulmonary mycosis is imperative in these patients and improved survival can be achieved with early CT detection and prompt institution of high-dose antifungal therapy.

  4. Computer aided product design

    DEFF Research Database (Denmark)

    Constantinou, Leonidas; Bagherpour, Khosrow; Gani, Rafiqul;

    1996-01-01

    A general methodology for Computer Aided Product Design (CAPD) with specified property constraints which is capable of solving a large range of problems is presented. The methodology employs the group contribution approach, generates acyclic, cyclic and aromatic compounds of various degrees......-liquid equilibria (LLE), solid-liquid equilibria (SLE) and gas solubility. Finally, a computer program based on the extended methodology has been developed and the results from five case studies highlighting various features of the methodology are presented....

  5. [AIDS in Africa].

    Science.gov (United States)

    Bolin, H

    1987-12-01

    Acquired immunodeficiency syndrome (AIDS) is believed to have begun in Rwanda with the transmission of green monkey virus to humans; the virus spread among prostitutes and truck drivers along the highways and then to the cities. In the most threatened areas, for example, Kinshasa in Zaire, 20% of the inhabitants are infected. 8% of pregnant women are human immunodeficiency virus (HIV)-positive. Social conditions are important. In Kenya prostitutes who work along the highways are carriers of socially transmitted diseases and genital sores. They are 60-80% HIV-positive. The better-off prostitutes at bars and hotels enjoy better health and fewer contacts and are 30% HIV-positive. It should be possible to develop a vaccine against the AIDS virus, but only a few virologists believe that this can be done within 10 years. Because HIV virus mutates rapidly, many different vaccines would have to be prepared. About 80 countries are cooperating with the World Health Organization to combat HIV and AIDS in Africa. Traveling and working abroad is beginning to be a problem. 15 countries have introduced restrictions on foreign visitors. Swedish midwives have an important role to play in fighting HIV. Their youth counseling activities can spread information about HIV and AIDS. Children who are in early stages of sexuality are probably the most important group to be influenced. It is already too late to begin informing 15-17 year olds about the disease. Midwives should probably be starting much sooner, perhaps even with 10-year olds. PMID:3692943

  6. Regeneration of Hydrotreating and FCC Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    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

  7. Atomically mixed Fe-group nanoalloys: catalyst design for the selective electrooxidation of ethylene glycol to oxalic acid.

    Science.gov (United States)

    Matsumoto, Takeshi; Sadakiyo, Masaaki; Ooi, Mei Lee; Yamamoto, Tomokazu; Matsumura, Syo; Kato, Kenichi; Takeguchi, Tatsuya; Ozawa, Nobuki; Kubo, Momoji; Yamauchi, Miho

    2015-05-01

    We demonstrate electric power generation via the electrooxidation of ethylene glycol (EG) on a series of Fe-group nanoalloy (NA) catalysts in alkaline media. A series of Fe-group binary NA catalysts supported on carbon (FeCo/C, FeNi/C, and CoNi/C) and monometallic analogues (Fe/C, Co/C, and Ni/C) were synthesized. Catalytic activities and product distributions on the prepared Fe-group NA catalysts in the EG electrooxidation were investigated by cyclic voltammetry and chronoamperometry, and compared with those of the previously reported FeCoNi/C, which clarified the contributory factors of the metal components for the EG electrooxidation activity, C2 product selectivity, and catalyst durability. The Co-containing catalysts, such as Co/C, FeCo/C, and FeCoNi/C, exhibit relatively high catalytic activities for EG electrooxidation, whereas the catalytic performances of Ni-containing catalysts are relatively low. However, we found that the inclusion of Ni is a requisite for the prevention of rapid degradation due to surface modification of the catalyst. Notably, FeCoNi/C shows the highest selectivity for oxalic acid production without CO2 generation at 0.4 V vs. the reversible hydrogen electrode (RHE), resulting from the synergetic contribution of all of the component elements. Finally, we performed power generation using the direct EG alkaline fuel cell in the presence of the Fe-group catalysts. The power density obtained on each catalyst directly reflected the catalytic performances elucidated in the electrochemical experiments for the corresponding catalyst. The catalytic roles and alloying effects disclosed herein provide information on the design of highly efficient electrocatalysts containing Fe-group metals. PMID:25848911

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lidong [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Zhou, Lu [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Ould-Chikh, Samy [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Anjum, Dalaver H. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Kanoun, Mohammed B. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Scaranto, Jessica [SABIC Corporate Research and Innovation Center, Thuwal (Saudi Arabia); Hedhili, Mohamed N. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Khalid, Syed [Brookhaven National Lab. (BNL), Upton, NY (United States); Laveille, Paco V. [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); D' Souza, Lawrence [SABIC Corporate Research and Innovation Center, Thuwal (Saudi Arabia); Clo, Alain [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia); Basset, Jean-Marie [King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia)

    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.

  9. Catalyst containing oxygen transport membrane

    Science.gov (United States)

    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.

  10. Hollow raspberry-like PdAg alloy nanospheres: High electrocatalytic activity for ethanol oxidation in alkaline media

    Science.gov (United States)

    Peng, Cheng; Hu, Yongli; Liu, Mingrui; Zheng, Yixiong

    2015-03-01

    Palladium-silver (PdAg) alloy nanospheres with unique structure were prepared using a one-pot procedure based on the galvanic replacement reaction. Their electrocatalytic activity for ethanol oxidation in alkaline media was evaluated. The morphology and crystal structure of the samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Electrochemical characterization techniques, including cyclic voltammetry (CV) and chronoamperometry (CA) measurements were used to analyze the electrochemical performance of the PdAg alloy nanospheres. The SEM and TEM images showed that the PdAg alloy nanospheres exhibit a hierarchical nanostructure with hollow interiors and porous walls. Compared to the commercial Pd/C catalyst, the as-prepared PdAg alloy nanospheres exhibit superior electrocatalytic activity and stability towards ethanol electro-oxidation in alkaline media, showing its potential as a new non-Pt electro-catalyst for direct alcohol fuel cells (DAFCs).

  11. Triangular Ag-Pd alloy nanoprisms: rational synthesis with high-efficiency for electrocatalytic oxygen reduction

    Science.gov (United States)

    Xu, Lin; Luo, Zhimin; Fan, Zhanxi; Zhang, Xiao; Tan, Chaoliang; Li, Hai; Zhang, Hua; Xue, Can

    2014-09-01

    We report the generation of triangular Ag-Pd alloy nanoprisms through a rationally designed synthetic strategy based on silver nanoprisms as sacrificial templates. The galvanic replacement between Ag nanoprisms and H2PdCl4 along with co-reduction of Ag+/Pd2+ is responsible for the formation of final prismatic Ag-Pd alloy nanostructures. Significantly, these Ag-Pd alloy nanoprisms exhibited superior electrocatalytic activity for the oxygen reduction reaction (ORR) as compared with the commercial Pd/C catalyst. Such a high catalytic activity is attributed to not only the alloyed Ag-Pd composition but also the dominant {111} facets of the triangular Ag-Pd nanoprisms. This work demonstrates the rational design of bimetallic alloy nanostructures with control of selective crystal facets that are critical to achieve high catalytic activity for fuel cell systems.We report the generation of triangular Ag-Pd alloy nanoprisms through a rationally designed synthetic strategy based on silver nanoprisms as sacrificial templates. The galvanic replacement between Ag nanoprisms and H2PdCl4 along with co-reduction of Ag+/Pd2+ is responsible for the formation of final prismatic Ag-Pd alloy nanostructures. Significantly, these Ag-Pd alloy nanoprisms exhibited superior electrocatalytic activity for the oxygen reduction reaction (ORR) as compared with the commercial Pd/C catalyst. Such a high catalytic activity is attributed to not only the alloyed Ag-Pd composition but also the dominant {111} facets of the triangular Ag-Pd nanoprisms. This work demonstrates the rational design of bimetallic alloy nanostructures with control of selective crystal facets that are critical to achieve high catalytic activity for fuel cell systems. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03600j

  12. The DynAlloy Visualizer

    OpenAIRE

    Bendersky, Pablo; Galeotti, Juan Pablo; Garbervetsky, Diego

    2014-01-01

    We present an extension to the DynAlloy tool to navigate DynAlloy counterexamples: the DynAlloy Visualizer. The user interface mimics the functionality of a programming language debugger. Without this tool, a DynAlloy user is forced to deal with the internals of the Alloy intermediate representation in order to debug a flaw in her model.

  13. Catalyst for Decomposition of Nitrogen Oxides

    Science.gov (United States)

    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.

  14. Use of lanthanide catalysts in air electrodes

    International Nuclear Information System (INIS)

    A review on the lanthanide catalysts suitable for the reduction catalysis of oxygen in air electrodes is presented. The kinds of lanthanide indicated to be used as catalysts of oxygen reduction are shown. (A.R.H.)

  15. Novel Fischer-Tropsch catalysts. [DOE patent

    Science.gov (United States)

    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.

  16. Biomass processing over gold catalysts

    CERN Document Server

    Simakova, Olga A; Murzin, Dmitry Yu

    2013-01-01

    The book describes the valorization of biomass-derived compounds over gold catalysts. Since biomass is a rich renewable feedstock for diverse platform molecules, including those currently derived from petroleum, the interest in various transformation routes has become intense. Catalytic conversion of biomass is one of the main approaches to improving the economic viability of biorefineries.  In addition, Gold catalysts were found to have outstanding activity and selectivity in many key reactions. This book collects information about transformations of the most promising and important compounds

  17. Quick Guide to Flash Catalyst

    CERN Document Server

    Elmansy, Rafiq

    2011-01-01

    How do you transform user interface designs created in Photoshop or Illustrator into interactive web pages? It's easier than you think. This guide shows you how to use Adobe Flash Catalyst to create interactive UIs and website wireframes for Rich Internet Applications-without writing a single line of code. Ideal for web designers, this book introduces Flash Catalyst basics with detailed step-by-step instructions and screenshots that illustrate every part of the process. You'll learn hands-on how to turn your static design or artwork into working user interfaces that can be implemented in Fla

  18. Colloidal nanoparticles as catalysts and catalyst precursors for nitrite hydrogenation

    NARCIS (Netherlands)

    Zhao, Yingnan

    2015-01-01

    The most distinguished advantage to use colloidal methods for catalyst preparation is that the size and the shape of nanoparticles can be manipulated easily under good control, which is normally difficult to achieve by using traditional methods, such as impregnation and precipitation. This facilitat

  19. Catalyst-assisted Probabilistic Entanglement Transformation

    OpenAIRE

    Feng, Yuan; Duan, Runyao; Ying, Mingsheng

    2004-01-01

    We are concerned with catalyst-assisted probabilistic entanglement transformations. A necessary and sufficient condition is presented under which there exist partial catalysts that can increase the maximal transforming probability of a given entanglement transformation. We also design an algorithm which leads to an efficient method for finding the most economical partial catalysts with minimal dimension. The mathematical structure of catalyst-assisted probabilistic transformation is carefully...

  20. Cotter's new plant diets on spent catalysts

    International Nuclear Information System (INIS)

    Cotter Corp.'s new 60-tpd spent-catalyst processing plant that recovers molybdenum, nickel, tungsten and vanadium products from spent catalysts is described. The company entered the business as a sideline to its main activity--the mining and processing of uranium ore. The spent-catalyst plant contains ammonium carbonate and sodium hydroxide leach circuits to provide the versatility required to recover various metals from a variety of spent catalysts

  1. Polymer-bound rhodium hydroformylation catalysts

    OpenAIRE

    Jongsma, Tjeerd

    1992-01-01

    Homogeneous catalysts are superior in activity, selectivity as well as specificity, but heterogeneous catalyst are often preferred in industrial processes, because of their good recoverability and their applicability in continuous flow reactors. It would be of great environmental, commercial and scientific interest to combine the advantages of both catalysts. A route to achieve this goal is to immobilize a potent homogeneous catalyst onto an insoluble resin. In this thesis we have used solubl...

  2. EFFECTS OF CATALYST MORPHOLOGY ON HYDROTREATING REACTIONS

    OpenAIRE

    TYE CHING THIAN

    2008-01-01

    Due to the new environmental regulations for fuel quality, refineries need to process cleaner fuel. This requires an improvement in performance of hydrotreating catalysts. Improvements in catalyst activity require knowledge of the relationships between catalyst morphology and activity. Molybdenum sulfide, the generally agreed catalysts that give the best performance in hydrocracking and hydrotreating was investigated for its morphology effects on hydrotreating reactions. Three types of MoS2 c...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gangwal, Santosh (Cary, NC); Jothimurugesan, Kandaswamy (Hampton, VA)

    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.

  5. Hydrogenation properties of nanostructured Ti2Ni-based alloys and nanocomposites

    Science.gov (United States)

    Balcerzak, M.; Jakubowicz, J.; Kachlicki, T.; Jurczyk, M.

    2015-04-01

    Mechanical alloying and annealing at 1023 K for 0.5 h under an argon atmosphere were used to prepare Ti2Ni-based nanocrystalline alloys and their nanocomposites. Ti2Ni alloy was chemically modified by Pd and multi-walled carbon nanotubes. An objective of the present study is to provide data on hydrogenation properties of Ti2Ni-based alloys and compounds containing Pd and/or multi-walled carbon nanotubes. Alloys and composites were characterized by X-ray diffraction, scanning electron microscopy equipped with an electron energy dispersive spectrometer, transmission electron microscopy, atomic force microscopy to evaluate phase composition, crystal structure, grain size, particle morphology and distribution of catalyst element. Hydrogenation/dehydrogenation properties and hydriding kinetics of materials were measured using a Sievert's apparatus. Hydrogenation properties of nanostructured Ti2Ni-based alloy and Ti2Ni-based nanocomposites were compared with those of the binary Ti2Ni compound. In present work we shown how mechanical alloying method and chemical modification by Pd and MWCNTs affected hydrogen storage properties of Ti2Ni alloy. The highest hydrogen capacity obtained for nanostructured Ti2Ni + Pd alloy equaled 2.1 wt.%. Up to our knowledge it is the highest hydrogen storage capacity obtained so far for Ti2Ni-based materials.

  6. High performing and stable supported nano-alloys for the catalytic hydrogenation of levulinic acid to gamma-valerolactone

    OpenAIRE

    Luo, Wenhao; Meenakshisundaram, Sankar; Beale, Andrew M; He, Qian; Kiely, Christopher J.; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

    2015-01-01

    The catalytic hydrogenation of levulinic acid, a key platform molecule in many biorefinery schemes, into gamma-valerolactone is considered as one of the pivotal reactions to convert lignocellulose-based biomass into renewable fuels and chemicals. Here we report on the development of highly active, selective and stable supported metal catalysts for this reaction and on the beneficial effects of metal nano-alloying. Bimetallic random alloys of gold-palladium and ruthenium-palladium supported on...

  7. High performing and stable supported nano-alloys for the catalytic hydrogenation of levulinic acid to γ-valerolactone

    OpenAIRE

    W. Luo; Sankar, M.; Beale, A.M.; Q. He; Kiely, C. J.; Bruijnincx, P. C.; Weckhuysen, B. M.

    2015-01-01

    The catalytic hydrogenation of levulinic acid, a key platform molecule in many biorefinery schemes, into γ-valerolactone is considered as one of the pivotal reactions to convert lignocellulose-based biomass into renewable fuels and chemicals. Here we report on the development of highly active, selective and stable supported metal catalysts for this reaction and on the beneficial effects of metal nano-alloying. Bimetallic random alloys of gold-palladium and ruthenium-palladium supported on tit...

  8. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes;

    2012-01-01

    Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared by...

  9. deNOx catalysts for biomass combustion

    DEFF Research Database (Denmark)

    Kristensen, Steffen Buus

    , however the alkali in biomass complicate matters. Alkali in biomass severely deactivates the catalyst used for the selective catalytic reduction in matter of weeks, hence a more alkali resistant catalyst is needed. In the thesis a solution to the problem is presented, the nano particle deNOx catalyst...

  10. Silver doped catalysts for treatment of exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Park, Paul Worn (Peoria, IL); Hester, Virgil Raymond (Edelstein, IL); Ragle, Christie Susan (Havana, IL); Boyer, Carrie L. (Shiloh, IL)

    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.

  11. Catalyst for selective oxidation of hydrocarbons

    OpenAIRE

    Álvaro Rodríguez, Mercedes; Amarajothi, Dhakshinamoorthy; García Gómez, Hermenegildo

    2010-01-01

    [EN] The present invention relates to a solid catalyst that includes a metal-organic reticular pattem and an agent promoting the generation of radicals, to a method for obtaining said catalyst and to the use thereof as a catalyst in the selective aerobic oxidation reaction ofhydrocarbons.

  12. Efficient epoxidation of propene using molecular catalysts

    DEFF Research Database (Denmark)

    Markovits, Iulius I. E.; Anthofer, Michael H.; Kolding, Helene; Cokoja, Mirza; Pöthig, Alexander; Raba, Andreas; Herrmann, Wolfgang A.; Fehrmann, Rasmus; Kühn, Fritz E.

    2014-01-01

    The epoxidation of propene is performed in homogeneous phase using various molecular catalysts and H2O2 or tert-butyl hydroperoxide as oxidants. A comparison between some molybdenum catalysts and methyltrioxorhenium (MTO) shows that the well known Re catalyst is the best among the examined...

  13. Carbon-Supported bimetallic Pd-Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Junming; Karim, Ayman M.; Zhang, He; Kovarik, Libor; Li, Xiaohong S.; Hensley, Alyssa; McEwen, Jean-Sabin; Wang, Yong

    2013-10-01

    Abstract Carbon supported metal catalysts (Cu/C, Fe/C, Pd/C, Pt/C, PdFe/C and Ru/C) have been prepared, characterized and tested for vapor-phase hydrodeoxygenation (HDO) of guaiacol (GUA) at atmospheric pressure. Phenol was the major intermediate on all catalysts. Over the noble metal catalysts saturation of the aromatic ring was the major pathway observed at low temperature (250 °C), forming predominantly cyclohexanone and cyclohexanol. Substantial ring opening reaction was observed on Pt/C and Ru/C at higher reaction temperatures (e.g., 350 °C). Base metal catalysts, especially Fe/C, were found to exhibit high HDO activity without ring-saturation or ring-opening with the main products being benzene, phenol along with small amounts of cresol, toluene and trimethylbenzene (TMB). A substantial enhancement in HDO activity was observed on the PdFe/C catalysts. Compared with Fe/C, the yield to oxygen-free aromatic products (i.e., benzene/toluene/TMB) on PdFe/C increased by a factor of four at 350 °C, and by approximately a factor of two (83.2% versus 43.3%) at 450 °C. The enhanced activity of PdFe/C is attributed to the formation of PdFe alloy as evidenced by STEM, EDS and TPR.

  14. Computational Chemistry-Based Identification of Ultra-Low Temperature Water-Gas-Shift Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Manos Mavrikakis

    2008-08-31

    The current work seeks to identify novel, catalytically-active, stable, poison-resistant LWGS catalysts that retain the superior activity typical of conventional Cu catalysts but can be operated at similar or lower temperatures. A database for the Binding Energies (BEs) of the LWGS relevant species, namely CO, O and OH on the most-stable, close-packed facets of a set of 17 catalytically relevant transition metals was established. This BE data and a database of previously established segregation energies was utilized to predict the stability of bimetallic NSAs that could be synthesized by combinations of the 17 parent transition metals. NSAs that were potentially stable both in vacuo and under the influence of strong-binding WGS intermediates were then selected for adsorption studies. A set of 40 NSAs were identified that satisfied all three screener criteria and the binding energies of CO, O and OH were calculated on a set of 66, 43 and 79 NSA candidates respectively. Several NSAs were found that bound intermediates weaker than the monometallic catalysts and were thus potentially poison-resistant. Finally, kinetic studies were performed and resulted in the discovery of a specific NSA-based bimetallic catalyst Cu/Pt that is potentially a promising LWGS catalyst. This stable Cu/Pt subsurface alloy is expected to provide facile H{sub 2}O activation and remain relatively resistant from the poisoning by CO, S and formate intermediates.

  15. Pregnancy and AIDS.

    Science.gov (United States)

    Henrion, R

    1988-02-01

    Since the first cases of a new acquired immunodeficiency syndrome (AIDS) described by Oleske et al. and Rubinstein et al. in children in 1983, we have witnessed an ever-increasing number of such observations. As serology is not being performed on all pregnant women in many European countries, obstetricians must try to identify those belonging to risk groups: intravenous drug abusers, natives of affected regions or women having travelled to these areas, women having numerous sexual partners, presenting with other sexually transmitted diseases or living with infected individuals, prostitutes, transfused women. If the woman belongs to risk groups, HIV antibody testing is to be done at the beginning of pregnancy. The risks for the mother remain ill-defined, due in part to the difficulties inherent in keeping track of heroin abusers. Aggravation is certain if the mother is affected with AIDS or an associated syndrome called ARC (AIDS-related complex). It is debatable and at least rarer if the mother presents no clinical symptoms. Infant risks are becoming better known. The existence of materno-fetal contamination by transplacental route is undebatable. However, contamination during delivery or during the passage through the maternal genital tract cannot be excluded. The proportion of contaminated infants is approximately 40%. The disease in the infant is highly dangerous. According to these data, the procedure adopted by most obstetricians is the following: abortion is recommended at the first trimester of the pregnancy, a free choice is left open for the woman at the second trimester and at the third trimester delivery is carried out naturally. Caesarean sections are only done when there are obstetrical indications.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3281969

  16. Computer aided engineering drawing

    CERN Document Server

    Dubey, N H

    2006-01-01

    This book caters to the need of First Year Engineering Students desiring to achieve a firm footage in the Subject Computer Aided Engineering Drawing. The formulation and methodology of the contents in this book is that one can easily understand the finer details of the subject and can master them with regular practice. It is essential that every on involved in engineering field must understand CAD for Drawing. This book contains well-illustrated figures along with theory for explaining procedures wherever necessary. A large number of solved and unsolved problems are provided so that one can ge

  17. Refocusing disaster aid.

    Science.gov (United States)

    Linnerooth-Bayer, Joanne; Mechler, Reinhard; Pflug, Georg

    2005-08-12

    With new modeling techniques for estimating and pricing the risks of natural disasters, the donor community is now in a position to help the poor cope with the economic repercussions of disasters by assisting before they happen. Such assistance is possible with the advent of novel insurance instruments for transferring catastrophe risks to the global financial markets. Donor-supported risk-transfer programs not only would leverage limited disaster-aid budgets but also would free recipient countries from depending on the vagaries of postdisaster assistance. Both donors and recipients stand to gain, especially because the instruments can be closely coupled with preventive measures. PMID:16099976

  18. First aid in mathematics

    CERN Document Server

    Sulley, Robert

    2014-01-01

    Achieve the best possible standard with this bestselling book of traditional practice and guidance - now in colour!. First Aid in Mathematics provides all the help and support needed for learning and practising Mathematics. It offers comprehensive coverage of core mathematical topics in clear and accessible language. It is suitable for both native English speakers and students of English as a second language and can be used in class, or as a reference and revision book. - Develops a strong basis of understanding with core topics covered in clear and accessible language. - Improves student's ab

  19. First aid at mines

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-01

    This Code of Practice has been approved by the Health and Safety Commission with the consent of the Secretary of State under section 16 of the Health and Safety at Work etc. Act 1974. It gives practical guidance on the requirements placed on employers and self-employed persons by the Health and Safety (First-Aid) Regulations 1981 as they now apply to mines and comes into effect on 1 October 1993 which is the date on which the Management and Administration of Safety and Health at Mines Regulations 1993 come into force.

  20. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    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.

  1. Biodiesel production using heterogenous catalyst

    Science.gov (United States)

    The current transesterification of triacylglycerides (TAG) to produce biodiesel is based on the homogenous catalyst method using strong base such as hydroxides or methoxides. However, this method results in a number of problems: (1) acid pre-treatment is required of feedstocks high in free fatty ac...

  2. Superplasticity in titanium alloys

    OpenAIRE

    J. Sieniawski; Motyka, M.

    2007-01-01

    Purpose: The paper reports characteristic of superplasticity phenomenon in titanium alloys and possibility of its applications.Design/methodology/approach: The main objective of the paper is to show features of superplastic forming of titanium alloys and current research trends aiming at widespread application of this technology.Findings: In the paper characteristic of selected superplastic titanium alloys was presented. The effect of microstructural parameters on superplasticity was consider...

  3. Mesoporous Pt and Pt/Ru alloy electrocatalysts for methanol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Franceschini, Esteban A. [Grupo de Celdas de Combustible, Departamento de Fisica de la Materia Condensada, Centro Atomico Constituyentes, CNEA. Av. General Paz 1499 (1650), San Martin, Buenos Aires (Argentina); Planes, Gabriel A. [Departamento de Quimica, Facultad de Ciencias Exactas, Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto, Agencia Postal No 3, 5800, Rio Cuarto (Argentina); Williams, Federico J. [Departamento de Quimica Inorganica, Analitica y Quimica-Fisica, INQUIMAE CONICET, Facultad Ciencias Exactas y Naturales, Pabellon 2, Ciudad Universitaria, Buenos Aires (Argentina); Soler-Illia, Galo J.A.A. [Gerencia de Quimica, Centro Atomico Constituyentes, CNEA. Av. General Paz 1499 (1650), San Martin, Buenos Aires (Argentina); Corti, Horacio R. [Grupo de Celdas de Combustible, Departamento de Fisica de la Materia Condensada, Centro Atomico Constituyentes, CNEA. Av. General Paz 1499 (1650), San Martin, Buenos Aires (Argentina); Departamento de Quimica Inorganica, Analitica y Quimica-Fisica, INQUIMAE CONICET, Facultad Ciencias Exactas y Naturales, Pabellon 2, Ciudad Universitaria, Buenos Aires (Argentina)

    2011-02-15

    Mesoporous Pt and Pt/Ru catalysts with 2D-hexagonal mesostructure were synthesized using a triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer (Pluronic F127 {sup registered}) template, on a gold support. Large electrochemical surface areas were observed for the catalysts prepared at high overpotentials. Compared to the Pt catalyst, the Pt/Ru alloy containing 3 at% of Ru exhibited lower onset potential and more than three times the limit mass activity for methanol oxidation. This behavior is assigned to the larger pore size of the mesoporous Pt and Pt/Ru catalysts obtained with this template that seems to improve the methanol accessibility to the active sites compared to those obtained using lyotropic liquid crystals. (author)

  4. Corrosion resistant amorphous alloys

    International Nuclear Information System (INIS)

    A review of publication data on corrosion resistance of amorphous alloys and the methods of amorphization of surface layers of massive materials (laser treatment, iron implantation, detonation-gas spraying, cathode and ion sputtering, electrodeposition) was made. A study was made on corrosion properties of Fe66Cr11B10Si4 alloy in cast state and after laser irradiation, rendering the surface amorphous as well as the samples of Arenco iron and steel 20 with ion-plasma coatings of Fe-Cr-Ni-Ti alloy. It was established that amorphous coatings posses much higher corrosion resistance as compared to crystalline alloys on the same base

  5. Toward Molecular Catalysts by Computer

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. AIDS-related myopathy.

    Science.gov (United States)

    Sheikh, Rafiq A.; Yasmeen, Shagufta; Munn, Robert; Ruebner, Boris H.; Ellis, William G.

    1999-09-01

    Infection with the human immunodeficiency virus (HIV) is often associated with the acquired immunodeficiency syndrome (AIDS), and wasting is one of the defining clinical features of AIDS. Muscular weakness due to myopathy may develop at any stage of HIV infection. We report two illustrative cases of HIV-associated myopathies. One was due to inflammatory myosits most likely directly related to the HIV infection, and the other was most likely the result of mitochondrial damage due to zidovudine, a nucleoside analogue commonly used in treating HIV infection. Biopsies from both patients showed alterations of myofiber structures, of varying severity, culminating in necrosis, lipid droplets, and lymphoplasmocytic inflammatory response. The zidovudine-treated patient also showed distinctive mitochondrial changes, predominantly enlargement, variation in shape and size, and disorganization of the cristae. These two types of HIV-associated inflammatory myopathies are reviewed, along with other HIV-associated myopathies, including HIV wasting syndrome, nemaline rod myopathy, pyomyositis, rhabdomyolysis, cardiomyopathy, and other miscellaneous myopathies associated with HIV infection. PMID:11810429

  7. Talking about AIDS

    Directory of Open Access Journals (Sweden)

    2003-09-01

    Full Text Available This paper explores the significance of social relationships to two important stages in the process of sexual behavioral change in response to increased HIV/AIDS risk in rural Africa: the perceived risk of becoming HIV-infected through unprotected sexual intercourse and the preferred methods of protection either through sexual fidelity, or through condom use. The empirical analyses are based on cross-sectional data from the 'Kenyan Diffusion and Ideational Change Project' (KDICP which provides information about AIDS-related, ego-centered communication networks of Kenyan men and women. The results show that perceived risks, as well as preferred methods of protection against HIV-infection, depend in general on the prevailing perceptions and favored protective methods within personal communication networks. However, different influential network properties can be found. The risk-perceptions of women are shaped by strong relationships and cohesive network structures. Male's risk perception depends more on the number of risk-perceivers in their communication networks. Heterogeneous relationships of various kinds are influential on women's and men's probability of favoring sexual faithfulness as a method of protection against HIV-infection.

  8. HIV/AIDS epidemiology.

    Science.gov (United States)

    Todd, C

    2000-10-14

    In this paper, Charles Todd comments that the report of Evan Wood and colleagues illustrates the dangers of taking a narrow medical view of the HIV/AIDS epidemic in Africa. It runs the risk of reversing the growing realization that the HIV/AIDS epidemic in southern Africa is a broad, social, cultural, political, and economic issue rather than a purely medical one. Todd raises the point that Wood and colleagues did not model the costs associated with the voluntary testing and counseling that should accompany a prophylaxis program. To this effect, a more helpful approach on meeting basic health needs and eradicating poverty would be to compare the impact of such levels of expenditure. It is also emphasized that the title of the paper of Wood and colleagues is misleading, implying that the focus of the modeling was sub-Saharan Africa as a whole, when it was in fact South Africa alone. Accordingly, the gross domestic product of South Africa per person is higher than that of nearly all other sub-Saharan African countries, and health expenditure is 10-20 times greater. PMID:11073053

  9. Aid Policy and the Macroeconomic Management of Aid

    DEFF Research Database (Denmark)

    Addison, Tony; Tarp, Finn

    2015-01-01

    This is an introduction to the UNU-WIDER special issue of World Development on aid policy and the macroeconomic management of aid. We provide an overview of the 10 studies, grouping them under three sub-themes: the aid–growth relationship; the supply-side of aid (including its level, volatility......, and coordination of donors); and the macroeconomic framework around aid. The studies in the special issue demonstrate the centrality of research methodology, the importance of disaggregation, and the need to account for country-specific situations and problems. This introduction concludes that the sometimes “over...

  10. Solvothermal synthesis of Pt-Pd alloys with selective shapes and their enhanced electrocatalytic activities

    Science.gov (United States)

    Zhang, Zhi-Cheng; Hui, Jun-Feng; Guo, Zhen-Guo; Yu, Qi-Yu; Xu, Biao; Zhang, Xin; Liu, Zhi-Chang; Xu, Chun-Ming; Gao, Jin-Sen; Wang, Xun

    2012-03-01

    Pt-Pd bimetallic alloy nanostructures with highly selective morphologies such as cube, bar, flower, concave cube, and dendrite have been achieved through a facile one-pot solvothermal synthesis. The effects of shape-controllers (sodium dodecyl sulfate (SDS), ethylenediamine-tetraacetic acid disodium salt (EDTA-2Na), NaI) and solvents (water/DMF) on the morphologies were systematically investigated. The electrocatalytic activities of these Pt-Pd alloy nanostructures toward formic acid oxidation were tested. The results indicated that these alloy nanocrystals exhibited enhanced and shape-dependent electrocatalytic activity toward formic acid oxidation compared to commercial Pt black and Pt/C catalysts.Pt-Pd bimetallic alloy nanostructures with highly selective morphologies such as cube, bar, flower, concave cube, and dendrite have been achieved through a facile one-pot solvothermal synthesis. The effects of shape-controllers (sodium dodecyl sulfate (SDS), ethylenediamine-tetraacetic acid disodium salt (EDTA-2Na), NaI) and solvents (water/DMF) on the morphologies were systematically investigated. The electrocatalytic activities of these Pt-Pd alloy nanostructures toward formic acid oxidation were tested. The results indicated that these alloy nanocrystals exhibited enhanced and shape-dependent electrocatalytic activity toward formic acid oxidation compared to commercial Pt black and Pt/C catalysts. Electronic supplementary information (ESI) available: See DOI: 10.1039/c2nr12135b

  11. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts

    Directory of Open Access Journals (Sweden)

    Nur Hidayati

    2016-03-01

    Full Text Available Even though platinum is known as an active electro-catalyst for ethanol oxidation at low temperatures (< 100 oC, choosing the electrode material for ethanol electro-oxidation is a crucial issue. It is due to its property which easily poisoned by a strong adsorbed species such as CO. PtSn-based electro-catalysts have been identified as better catalysts for ethanol electro-oxidation. The third material is supposed to improved binary catalysts performance. This work presents a study of the ethanol electro-oxidation on carbon supported Pt-Sn and Pt-Sn-Ni catalysts. These catalysts were prepared by alcohol reduction. Nano-particles with diameters between 2.5-5.0 nm were obtained. The peak of (220 crystalline face centred cubic (fcc Pt phase for PtSn and PtSnNi alloys was repositioned due to the presence of Sn and/or Ni in the alloy. Furthermore, the modification of Pt with Sn and SnNi improved ethanol and CO electro-oxidation. Copyright © 2016 BCREC GROUP. All rights reserved Received: 10th November 2015; Revised: 1st February 2016; Accepted: 1st February 2016 How to Cite: Hidayati, N., Scott, K. (2016. Electro-oxidation of Ethanol on Carbon Supported PtSn and PtSnNi Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 10-20. (doi:10.9767/bcrec.11.1.394.10-20 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.394.10-20

  12. Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

    Directory of Open Access Journals (Sweden)

    Mallika Gummalla

    2015-05-01

    Full Text Available The initial performance and decay trends of polymer electrolyte membrane fuel cells (PEMFC cathodes with Pt3Co catalysts of three mean particle sizes (4.9 nm, 8.1 nm, and 14.8 nm with identical Pt loadings are compared. Even though the cathode based on 4.9 nm catalyst exhibited the highest initial electrochemical surface area (ECA and mass activity, the cathode based on 8.1 nm catalyst showed better initial performance at high currents. Owing to the low mass activity of the large particles, the initial performance of the 14.8 nm Pt3Co-based electrode was the lowest. The performance decay rate of the electrodes with the smallest Pt3Co particle size was the highest and that of the largest Pt3Co particle size was lowest. Interestingly, with increasing number of decay cycles (0.6 to 1.0 V, 50 mV/s, the relative improvement in performance of the cathode based on 8.1 nm Pt3Co over the 4.9 nm Pt3Co increased, owing to better stability of the 8.1 nm catalyst. The electron microprobe analysis (EMPA of the decayed membrane-electrode assembly (MEA showed that the amount of Co in the membrane was lower for the larger particles, and the platinum loss into the membrane also decreased with increasing particle size. This suggests that the higher initial performance at high currents with 8.1 nm Pt3Co could be due to lower contamination of the ionomer in the electrode. Furthermore, lower loss of Co from the catalyst with increased particle size could be one of the factors contributing to the stability of ECA and mass activity of electrodes with larger cathode catalyst particles. To delineate the impact of particle size and alloy effects, these results are compared with prior work from our research group on size effects of pure platinum catalysts. The impact of PEMFC operating conditions, including upper potential, relative humidity, and temperature on the alloy catalyst decay trends, along with the EMPA analysis of the decayed MEAs, are reported.

  13. Highly Active Carbon Supported Pd-Ag Nanofacets Catalysts for Hydrogen Production from HCOOH.

    Science.gov (United States)

    Wang, Wenhui; He, Ting; Liu, Xuehua; He, Weina; Cong, Hengjiang; Shen, Yangbin; Yan, Liuming; Zhang, Xuetong; Zhang, Jinping; Zhou, Xiaochun

    2016-08-17

    Hydrogen is regarded as a future sustainable and clean energy carrier. Formic acid is a safe and sustainable hydrogen storage medium with many advantages, including high hydrogen content, nontoxicity, and low cost. In this work, a series of highly active catalysts for hydrogen production from formic acid are successfully synthesized by controllably depositing Pd onto Ag nanoplates with different Ag nanofacets, such as Ag{111}, Ag{100}, and the nanofacet on hexagonal close packing Ag crystal (Ag{hcp}). Then, the Pd-Ag nanoplate catalysts are supported on Vulcan XC-72 carbon black to prevent the aggregation of the catalysts. The research reveals that the high activity is attributed to the formation of Pd-Ag alloy nanofacets, such as Pd-Ag{111}, Pd-Ag{100}, and Pd-Ag{hcp}. The activity order of these Pd-decorated Ag nanofacets is Pd-Ag{hcp} > Pd-Ag{111} > Pd-Ag{100}. Particularly, the activity of Pd-Ag{hcp} is up to an extremely high value, i.e., TOF{hcp} = 19 000 ± 1630 h(-1) at 90 °C (lower limit value), which is more than 800 times higher than our previous quasi-spherical Pd-Ag alloy nanocatalyst. The initial activity of Pd-Ag{hcp} even reaches (3.13 ± 0.19) × 10(6) h(-1) at 90 °C. This research not only presents highly active catalysts for hydrogen generation but also shows that the facet on the hcp Ag crystal can act as a potentially highly active catalyst. PMID:27454194

  14. Electrochemical and Structural Study of a Chemically Dealloyed PtCu Oxygen Reduction Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Indrajit; Carpenter, Michael K.; Balogh, Michael P.; Ziegelbauer, Joseph M.; Moylan, Thomas E.; Atwan, Mohammed H.; Irish, Nicholas P. (Trison Business Solutions); (General Motors Corp.)

    2010-10-22

    A carbon-supported, dealloyed platinum-copper (Pt-Cu) oxygen reduction catalyst was prepared using a multistep synthetic procedure. Material produced at each step was characterized using high-angle annular dark-field scanning transmission electron microscopy, electron energy loss spectroscopy mapping, X-ray absorption spectroscopy, X-ray diffraction, and cyclic voltammetry, and its oxygen reduction reaction (ORR) activity was measured by a thin-film rotating disk electrode technique. The initial synthetic step, a coreduction of metal salts, produced a range of poorly crystalline Pt, Cu, and Pt-Cu alloy nanoparticles that nevertheless exhibited good ORR activity. Annealing this material alloyed the metals and increased particle size and crystallinity. Transmission electron microscopy shows the annealed catalyst to include particles of various sizes, large (>25 nm), medium (12-25 nm), and small (<12 nm). Most of the small and medium-sized particles exhibited a partial or complete core-shell (Cu-rich core and Pt shell) structure with the smaller particles typically having more complete shells. The appearance of Pt shells after annealing indicates that they are formed by a thermal diffusion mechanism. Although the specific activity of the catalyst material was more than doubled by annealing, the concomitant decrease in Pt surface area resulted in a drop in its mass activity. Subsequent dealloying of the catalyst by acid treatment to partially remove the copper increased the Pt surface area by changing the morphology of the large and some medium particles to a 'Swiss cheese' type structure having many voids. The smaller particles retained their core-shell structure. The specific activity of the catalyst material was little reduced by dealloying, but its mass activity was more than doubled due to the increase in surface area. The possible origins of these results are discussed in this report.

  15. Hydroprocessing using regenerated spent heavy hydrocarbon catalyst

    International Nuclear Information System (INIS)

    This patent describes a process for hydroprocessing a hydrocarbon feedstock. It comprises: contacting the feedstock with hydrogen under hydroprocessing conditions with a hydroprocessing catalyst wherein the hydroprocessing catalyst contains a total contaminant metals build-up of greater than about 4 wt. % nickel plus vanadium, a hydrogenation component selected from the group consisting of Group VIB metals and Group VIII metals and is regenerated spent hydroprocessing catalyst regenerated by a process comprising the steps: partially decoking the spent catalyst in an initial coke-burning step; impregnating the partially decoked catalyst with a Group IIA metal-containing impregnation solution; and decoking the impregnated catalyst in a final coke-burning step wherein the impregnated catalyst is contacted with an oxygen-containing gas at a temperature of about 600 degrees F to about 1400 degrees F

  16. Autothermal reforming catalyst having perovskite structure

    Science.gov (United States)

    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.

  17. Direct decomposition of methane over SBA-15 supported Ni, Co and Fe based bimetallic catalysts

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Synthesis and characterization of Ni, Co and Fe based bimetallic catalysts supported over SBA-15. • Thermocatalytic decomposition of methane over the SBA-15 supported bimetallic catalysts. • Enhanced catalytic efficiency of the bimetallic catalysts for the production of COx free hydrogen and nanocarbon. • Production of value added open tip hollow multi-walled carbon nanotubes. • Crystalline characterization of carbon nanotubes by XRD, Raman and thermogravimetric analysis. - Abstract: Thermocatalytic decomposition of methane is an alternative route for the production of COx-free hydrogen and carbon nanomaterials. In this work, a set of novel Ni, Co and Fe based bimetallic catalysts supported over mesoporous SBA-15 was synthesized by a facile wet impregnation route, characterized for their structural, textural and reduction properties and were successfully used for the methane decomposition. The fine dispersion of metal oxide particles on the surface of SBA-15, without affecting its mesoporous texture was clearly shown in the low angle X-ray diffraction patterns and the transmission electron microscopy (TEM) images. The nitrogen sorption analysis showed the reduced specific surface area and pore volume of SBA-15, after metal loading due to the partial filling of hexagonal mesopores by metal species. The results of methane decomposition experiments indicated that all of the bimetallic catalysts were highly active and stable for the reaction at 700 °C even after 300 min of time on stream (TOS). However, a maximum hydrogen yield of ∼56% was observed for the NiCo/SBA-15 catalyst within 30 min of TOS. A high catalytic stability was shown by the CoFe/SBA-15 catalyst with 51% of hydrogen yield during the course of reaction. The catalytic stability of the bimetallic catalysts was attributed to the formation of bimetallic alloys. Moreover, the deposited carbons were found to be in the form of a new set of hollow multi

  18. Direct decomposition of methane over SBA-15 supported Ni, Co and Fe based bimetallic catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Pudukudy, Manoj, E-mail: manojpudukudy@gmail.com [Fuel Cell Institute, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia); Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia); Yaakob, Zahira, E-mail: zahirayaakob65@gmail.com [Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia); Akmal, Zubair Shamsul [Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, UKM, Bangi 43600, Selangor (Malaysia)

    2015-03-01

    Graphical abstract: - Highlights: • Synthesis and characterization of Ni, Co and Fe based bimetallic catalysts supported over SBA-15. • Thermocatalytic decomposition of methane over the SBA-15 supported bimetallic catalysts. • Enhanced catalytic efficiency of the bimetallic catalysts for the production of CO{sub x} free hydrogen and nanocarbon. • Production of value added open tip hollow multi-walled carbon nanotubes. • Crystalline characterization of carbon nanotubes by XRD, Raman and thermogravimetric analysis. - Abstract: Thermocatalytic decomposition of methane is an alternative route for the production of CO{sub x}-free hydrogen and carbon nanomaterials. In this work, a set of novel Ni, Co and Fe based bimetallic catalysts supported over mesoporous SBA-15 was synthesized by a facile wet impregnation route, characterized for their structural, textural and reduction properties and were successfully used for the methane decomposition. The fine dispersion of metal oxide particles on the surface of SBA-15, without affecting its mesoporous texture was clearly shown in the low angle X-ray diffraction patterns and the transmission electron microscopy (TEM) images. The nitrogen sorption analysis showed the reduced specific surface area and pore volume of SBA-15, after metal loading due to the partial filling of hexagonal mesopores by metal species. The results of methane decomposition experiments indicated that all of the bimetallic catalysts were highly active and stable for the reaction at 700 °C even after 300 min of time on stream (TOS). However, a maximum hydrogen yield of ∼56% was observed for the NiCo/SBA-15 catalyst within 30 min of TOS. A high catalytic stability was shown by the CoFe/SBA-15 catalyst with 51% of hydrogen yield during the course of reaction. The catalytic stability of the bimetallic catalysts was attributed to the formation of bimetallic alloys. Moreover, the deposited carbons were found to be in the form of a new set of hollow

  19. Joining of yttria-tetragonal zirconia polycrystal with an aluminum-zirconium alloy

    International Nuclear Information System (INIS)

    Specimens of yttria-tetragonal zirconia polycrystal (Y-TZP) have been joined with an Al-5.8 wt% Zr alloy at temperatures of 900 degrees C and above. The braze alloy contained large needlelike precipitates of the intermetallic phase Al3Sr. It is shown that these large precipitates can aid in strengthening of the joint, especially if they are close to the interface. With decreasing layer thickness, the strengths increased with values as high as 420 MPa

  20. Catalyst for Carbon Monoxide Oxidation

    Science.gov (United States)

    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

  1. Aid, social policy, and development

    DEFF Research Database (Denmark)

    Addison, Tony; Niño-Zarazúa, Miguel; Tarp, Finn

    This paper discusses past and current social policy strategies in the international aid architecture. From the 1990s, aid strategy and policy shifted to put a stronger emphasis on human development. This accelerated with the Millennium Development Goals and will continue under the Sustainable...... Development Goals, which have even more ambitious targets. The paper also assesses some of the concerns associated with the ‘Paris-style’ aid modalities, and discusses major challenges for the future global development agenda....

  2. Aid, social policy, and development

    OpenAIRE

    Addison, Tony; Niño-Zarazúa, Miguel; Tarp, Finn

    2015-01-01

    This paper discusses past and current social policy strategies in the international aid architecture. From the 1990s, aid strategy and policy shifted to put a stronger emphasis on human development. This accelerated with the Millennium Development Goals and will continue under the Sustainable Development Goals, which have even more ambitious targets. The paper also assesses some of the concerns associated with the 'Paris-style' aid modalities, and discusses major challenges for the future glo...

  3. The Consequences of Merit Aid

    OpenAIRE

    2002-01-01

    Since the early Nineties, a dozen states have established broad-based merit aid programs. The typical program waives tuition and fees at public colleges and universities in one's home state. Unlike traditional merit programs, such as the National Merit Scholarship, this aid requires relatively modest academic performance and provide scholarships to hundreds of thousands of students. This paper examines how merit aid programs in seven states have affected an array of schooling decisions, payin...

  4. Aid and sectoral labour productivity

    OpenAIRE

    Selaya, Pablo; Thiele, Rainer

    2008-01-01

    The paper examines empirically the proposition that aid to poor countries is detrimental for external competitiveness, giving rise to Dutch disease type effects. At the aggregate level, aid is found to have a positive effect on growth of labour productivity. A sectoral decomposition shows that the effect is significant and positive both in the tradables and the nontradables sectors. The paper thus finds no empirical support for the hypothesis that aid reduces external competitiveness in devel...

  5. National HIV/AIDS Strategy

    Centers for Disease Control (CDC) Podcasts

    2012-02-01

    Dr. Kevin Fenton, Director of CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, talks about the importance of the National HIV/AIDS Strategy and the work of CDC.  Created: 2/1/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 2/1/2012.

  6. National Latino AIDS Awareness Day

    Centers for Disease Control (CDC) Podcasts

    2014-10-08

    This podcast highlights National Latino AIDS Awareness Day, to increase awareness of the disproportionate impact of HIV on the Hispanic or Latino population in the United States and dependent territories. The podcast reminds Hispanics or Latinos that they have the power to take control of their health and protect themselves against HIV.  Created: 10/8/2014 by Office of Health Equity, Office of the Director, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD and TB Prevention, Division of HIV/AIDS Prevention.   Date Released: 10/14/2014.

  7. Controlled CVD growth of Cu-Sb alloy nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jing; Yin Zongyou; Sim, Daohao; Tay, Yee Yan; Zhang Hua; Ma Jan; Hng, Huey Hoon; Yan Qingyu, E-mail: alexyan@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2011-08-12

    Sb based alloy nanostructures have attracted much attention due to their many promising applications, e.g. as battery electrodes, thermoelectric materials and magnetic semiconductors. In many cases, these applications require controlled growth of Sb based alloys with desired sizes and shapes to achieve enhanced performance. Here, we report a flexible catalyst-free chemical vapor deposition (CVD) process to prepare Cu-Sb nanostructures with tunable shapes (e.g. nanowires and nanoparticles) by transporting Sb vapor to react with copper foils, which also serve as the substrate. By simply controlling the substrate temperature and distance, various Sb-Cu alloy nanostructures, e.g. Cu{sub 11}Sb{sub 3} nanowires (NWs), Cu{sub 2}Sb nanoparticles (NPs), or pure Sb nanoplates, were obtained. We also found that the growth of Cu{sub 11}Sb{sub 3} NWs in such a catalyst-free CVD process was dependent on the substrate surface roughness. For example, smooth Cu foils could not lead to the growth of Cu{sub 11}Sb{sub 3} nanowires while roughening these smooth Cu foils with rough sand papers could result in the growth of Cu{sub 11}Sb{sub 3} nanowires. The effects of gas flow rate on the size and morphology of the Cu-Sb alloy nanostructures were also investigated. Such a flexible growth strategy could be of practical interest as the growth of some Sb based alloy nanostructures by CVD may not be easy due to the large difference between the condensation temperature of Sb and the other element, e.g. Cu or Co.

  8. Characterization and electrocatalytic properties of PtRu/C catalysts prepared by impregnation-reduction method using Nd2O3 as dispersing reagent

    International Nuclear Information System (INIS)

    A simple impregnation-reduction method introducing Nd2O3 as dispersing reagent has been used to synthesize PtRu/C catalysts with uniform Pt-Ru spherical nanoparticles. X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis have been used to characterize the composition, particle size and crystallinity of the catalysts. Well-dispersed catalysts with average particle size about 2 nm are achieved. The electrochemically active surface area of the different PtRu/C catalysts is determined by the COad-stripping voltammetry experiment. The electrocatalytic activities of these catalysts towards methanol electrooxidation are investigated by cyclic voltammetry measurements and ac impedance spectroscopy. The in-house prepared PtRu/C catalyst (PtRu/C-03) in 0.5 M H2SO4 + 1.0 M CH3OH at 30 deg. C display a higher catalytic activity and lower charge-transfer resistance (R t) than that of the standard PtRu/C catalyst (PtRu/C-C). It is mainly due to enhanced electrochemically active specific surface, higher alloying extent of Ru and the abundant Pt and Ru oxides on the surface of the PtRu/C catalyst

  9. Synthesis and characterization of ternary Pt-Ni-M/C (M=Cu, Fe, Ce, Mo, W) nano-catalysts for low temperature fuel cells

    International Nuclear Information System (INIS)

    Ternary metal catalysts were synthesized by impregnation method. The mixture of metal solutions was reduced slowly under inert atmosphere and the reduced metals were deposited on the Vulcan Carbon(VC). Tungsten, molybdenum, cerium, iron and copper were added to specified amounts of platinum and nickel. Addition of nickel generally improves catalytic activity of platinum. The XRD of the catalysts was done and the crystallite size and other parameters were calculated. Crystallite sizes were in the range of 5 to 16 nm. Electrochemical surface areas of the catalysts were determined by cyclic voltammetry (CV) in acidic media and are compared. Electro oxidation of methanol on the catalysts was done and peak potential, peak current, mass activity of the catalysts were calculated and are compared. These parameters were determined in acidic and basic media. It was found that mass activity increased significantly in basic media. Rate constants for the electro oxidation of methanol were also calculated in acidic and basic media and are compared and discussed. Rate constants were generally higher in basic media. Ternary catalysts showed improved catalytic activity than the binary catalyst. Nano alloying improved the catalytic activity and stability of the ternary catalysts

  10. Ergogenic Aids and Supplements.

    Science.gov (United States)

    Porrini, Marisa; Del Boʼ, Cristian

    2016-01-01

    Great interest is currently shown for the contribution of nutrition to optimize training and athletic performance, and a considerable debate exists about the potential ergogenic value of several dietary supplements. However, most of the products used by athletes do not provide sufficient scientific evidence regarding their efficacy in enhancing physical performance as well as their specificity of action and safety. For this reason, sport nutrition professionals need skills in evaluating the scientific value of papers and advertisements on ergogenic aids and supplements in order to support athletes in their choice. In the present chapter, the efficacy of some of the most popular supplements used by athletes and sport practitioners will be discussed. Particular attention will be devoted to amino acids and derivatives, caffeine and caffeinated energy drinks, and some antioxidants. PMID:27348226

  11. Learning to aid learning.

    Science.gov (United States)

    Richards, Jacqui

    2016-01-01

    The National Health Service (NHS) is one of the largest employers in the world and, with 1.3 million staff, the biggest employer in Europe. With over three hundred different careers on offer (NHS 2015), the acquisition of skills and qualifications, through academic and clinical training, is an integral part of day-to-day life in the health service. As such, mentoring has become a significant feature in the preparation of healthcare professionals, to support students and ensure learning needs and experiences are appropriate to competency. This article examines the mentor's role, in relation to a teaching innovation designed to address students' identified learning needs to meet the requirements of the multi-professional learning and assessment in practice course NM6156. The effectiveness of the aids to learning will be assessed through an online quiz, and its usefulness will be analysed with reference to educational theories of learning and development. PMID:26975128

  12. AIDS Care Ignores Children

    Institute of Scientific and Technical Information of China (English)

    Apoorva; Mandavilli; 张祖明

    2005-01-01

    艾滋病的全称为"获得性免疫缺陷综合症(AIDS)",通过性、血液和母婴三种接触方式传播,是一种严重危害健康的传染性疾病。它通过破坏人的免疫系统和机体抵抗能力给人以致命的打击,被称为"超级绝症"。儿童感染艾滋病通常是由于母体传播的,但是他们却成为艾滋病防治过程中的一个"盲点"。究竟为什么呢?请看下文。

  13. Nb-doped TiO2/carbon composite supports synthesized by ultrasonic spray pyrolysis for proton exchange membrane (PEM) fuel cell catalysts

    Science.gov (United States)

    Senevirathne, Keerthi; Neburchilov, Vladimir; Alzate, Vanesa; Baker, Ryan; Neagu, Roberto; Zhang, Jiujun; Campbell, Stephen; Ye, Siyu

    2012-12-01

    In this paper we report the use of both ultrasonic spray pyrolysis and microwave-assisted polyol reduction methods to synthesize Nb-doped TiO2/carbon (25 wt% Nb0.07Ti0.93O2/75 wt% carbon) composite supports and Pt0.62Pd0.38 alloy catalysts, respectively. The physicochemical properties of the synthesized supports and their Pt0.62Pd0.38 supported catalysts are evaluated using several methods including XRD, TEM, BET surface area analysis, TGA, as well as ICP-MS elemental analysis. The electronic conductivities and thermal/chemical stabilities of the supports are also evaluated with respect to their possible use as catalyst supports. Electrochemical measurements for oxygen reduction activity of the Pt0.62Pd0.38 alloy catalysts supported on oxide/carbon composites are also carried out in order to check their suitability for possible PEM fuel cell applications. The results show that 20wt%Pt0.62Pd0.38/25 wt%(Nb0.07Ti0.93O2)-75 wt%C catalysts exhibit enhanced mass activities compared to those of commercially available 48wt% Pt/C and home-made 20wt% Pt62Pd38/C catalysts.

  14. Aids and Infectious Diseases (aid) Pmp 2013 Report

    Science.gov (United States)

    Buonaguro, Franco M.

    2014-07-01

    The AIDS and Infectious Diseases (AID) PMP of the WFS contributed this year with a session on August 22nd to the Plenary Sessions of the International Seminars on Planetary Emergencies and Associated Meetings--46th Session: The Role of Science in the Third Millennium (Erice, 19-24 August 2013). Furthermore a workshop on August 24th was organized...

  15. Thermofluency in zirconium alloys

    International Nuclear Information System (INIS)

    A summary is presented about the theoretical and experimental results obtained at present in thermofluency under radiation in zirconium alloys. The phenomenon of thermofluency is presented in a general form, underlining the thermofluency at high temperature because this phenomenon is similar to the thermofluency under radiation, which ocurrs in zirconium alloys into the operating reactor. (author)

  16. High temperature niobium alloys

    International Nuclear Information System (INIS)

    Niobium alloys are currently being used in various high temperature applications such as rocket propulsion, turbine engines and lighting systems. This paper presents an overview of the various commercial niobium alloys, including basic manufacturing processes, properties and applications. Current activities for new applications include powder metallurgy, coating development and fabrication of advanced porous structures for lithium cooled heat pipes

  17. Radiation induced segregation and point defects in binary copper alloys

    International Nuclear Information System (INIS)

    Considerable progress, both theoretical and experimental, has been made in establishing and understanding the influence of factors such as temperature, time, displacement rate dependence and the effect of initial solute misfit on radiation induced solute diffusion and segregation. During irradiation, the composition of the alloy changes locally, due to defect flux driven non-equilibrium segregation near sinks such as voids, external surfaces and grain boundaries. This change in composition could influence properties and phenomena such as ductility, corrosion resistance, stress corrosion cracking, sputtering and blistering of materials used in thermo-nuclear reactors. In this work, the effect of 1 MeV electron irradiation on the initiation and development of segregation and defect diffusion in binary copper alloys has been studied in situ, with the aid of a high voltage electron microscope. The binary copper alloys had Be, Pt and Sn as alloying elements which had atomic radii less than, similar and greater than that of copper, respectively. It has been observed that in a wide irradiation temperature range, stabilization and growth of dislocation loops took place in Cu-Sn and Cu-Pt alloys. Whereas in the Cu-Be alloy, radiation induced precipitates formed and transformed to the stable γ phase. (Author)

  18. Ultrahigh temperature intermetallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brady, M.P.; Zhu, J.H.; Liu, C.T.; Tortorelli, P.F.; Wright, J.L.; Carmichael, C.A.; Walker, L.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-01

    A new family of Cr-Cr{sub 2}X based alloys with fabricability, mechanical properties, and oxidation resistance superior to previously developed Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys has been identified. The new alloys can be arc-melted/cast without cracking, and exhibit excellent room temperature and high-temperature tensile strengths. Preliminary evaluation of oxidation behavior at 1100 C in air indicates that the new Cr-Cr{sub 2}X based alloys form an adherent chromia-based scale. Under similar conditions, Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys suffer from extensive scale spallation.

  19. Alloys in energy development

    International Nuclear Information System (INIS)

    The development of new and advanced energy systems often requires the tailoring of new alloys or alloy combinations to meet the novel and often stringent requirements of those systems. Longer life at higher temperatures and stresses in aggressive environments is the most common goal. Alloy theory helps in achieving this goal by suggesting uses of multiphase systems and intermediate phases, where solid solutions were traditionally used. However, the use of materials under non-equilibrium conditions is now quite common - as with rapidly solidified metals - and the application of alloy theory must be modified accordingly. Under certain conditions, as in a reactor core, the rate of approach to equilibrium will be modified; sometimes a quasi-equilibrium is established. Thus an alloy may exhibit enhanced general diffusion at the same time as precipitate particles are being dispersed and solute atoms are being carried to vacancy sinks. We are approaching an understanding of these processes and can begin to model these complex systems

  20. XVII International AIDS Conference: From Evidence to Action - AIDS 2008 and the global response to AIDS

    OpenAIRE

    Kort, Rodney

    2009-01-01

    The impact of the XVII International AIDS Conference (AIDS 2008) was reflected in a number of commitments from political and business leaders, who announced initiatives ranging from implementing comprehensive sexual education for young people in Latin America to reducing regulatory barriers and the price of drugs in the host country. The unprecedented media coverage brought attention and public awareness to the epidemic in Latin America. Several meetings and sessions at AIDS 2008 also address...