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...... of the novel catalyst material for synthesising hydrogen peroxide from oxygen and hydrogen, or from oxygen and water....

  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. 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

  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. 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 compositi...... 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....

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...... focus on the surface properties. Based on a genetic algorithm (GA) we introduce and discuss efficient permutation operations that work by interchanging positions of elements depending on their local environment and position in the cluster. We discuss the fact that in order to be efficient, the operators...... have to be dynamic, i.e. change their behavior during the course of an algorithm run. The implementation of the GA including the customized operators is freely available at http://svn.fysik.dtu. dk/projects/pga....

  11. 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.

  12. Computational thermodynamics aided design of novel ferritic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying [ORNL; Tan, Lizhen [ORNL

    2016-07-01

    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.

  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. 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)

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    calculations were performed that identified relations in heats of adsorption of hydrocarbon molecules and fragments on metal surfaces. This analysis not only verified the facility of known catalysts but identified nickel- zinc alloys as alternatives. Experimental studies demonstrated that these alloys...... dispersed on an oxide support were selective for acetylene hydrogenation at low pressures....

  16. 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 high...

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

    DEFF Research Database (Denmark)

    Vej-Hansen, Ulrik Grønbjerg

    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 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...

  18. 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.

  19. 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.

  20. A Novel Ultrafine Ru-B Amorphous Alloy Catalyst for Glucose Hydrogenation to Sorbitol

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An ultrafine Ru-B amorphous alloy catalyst was prepared by chemical reduction with KBH4 in aqueous solution, which exhibited perfect selectivity to sorbitol (~100%) and very high activity during the liquid phase glucose hydrogenation, much higher than the corresponding crystallized Ru-B, the pure Ru powder, and Raney Ni catalysts. The correlation of the catalytic activity to both the structural and surface electronic characteristics was discussed briefly.

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

    Institute of Scientific and Technical Information of China (English)

    MuXuhong; ZongBaoning; 等

    2002-01-01

    Amorphous nickel based alloy catalysts(denoted as the SRNA series catalysts)were prepared via rapid quenching method followed by alkali leaching and other activation procedures.The physicochemical characterizations show that nickel,the active component in these catalysts,exists in the amorphous state,and the catalyst particles possess many nanosized voids leading to large surface area(the highest is 145m2/g).The evaluation results in some model reactions show that the SRNA series catalysts have 2 to 4 times higher activity and selectivity than conventional Raney Ni catalyst for the hydrogenation of compounds with unsatur-ated functional groups.At present,the SRNA series catalysts have been successfully used in hydrogenation of glucose,hydrogenation of pharmaceutical intermediates and purification of caprolactam.In order to use these catalysts efficiently,a magnetically stabilized bed(MSB) technology has been developed by combining the ferromagnetic property of the catalyst with the good mass transfer characteristics of MSB.The demonstration unit of MSB hydrogenation technology has been set up and has kept running for 2800 hours.The results show that,after running 2800 hours,the catalyst still retained good activity; meanwhile,the hydrogenation effi-ciency had been improved 10 times in comparison with the traditional CSTR process.

  2. 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.

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Amorphous nickel based alloy catalysts (denoted as the SRNA series catalysts) were prepared viarapid quenching method followed by alkali leaching and other activation procedures. The physicochemicalcharacterizations show that nickel, the active component in these catalysts, exists in the amorphous state, andthe catalyst particles possess many nanosized voids leading to large surface area (the highest is 145m2/g). Theevaluation results in some model reactions show that the SRNA series catalysts have 2 to 4 times higheractivity and selectivity than conventional Raney Ni catalyst for the hydrogenation of compounds with unsatur-ated functional groups. At present, the SRNA series catalysts have been successfully used in hydrogenation ofglucose, hydrogenation of pharmaceutical intermediates and purification of caprolactam. In order to use thesecatalysts efficiently, a magnetically stabilized bed (MSB) technology has been developed by combining theferromagnetic property of the catalyst with the good mass transfer characteristics of MSB. The demonstrationunit of MSB hydrogenation technology has been set up and has kept running for 2800 hours. The results showthat, after running 2800 hours, the catalyst still retained good activity; meanwhile, the hydrogenation effi-ciency had been improved 10 times in comparison with the traditional CSTR process.

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

    Institute of Scientific and Technical Information of China (English)

    Mu Xuhong; Zong Baoning; Meng Xiangkun; Min Enze

    2002-01-01

    Amorphous nickel based alloy catalysts (denoted as the SRNAseries catalysts) were prepared viarapid quenching method followed by alkali leaching and other activation procedures. The physicochemicalcharacterizations show that nickel, the active component in these catalysts, exists in the amorphous state, andthe catalyst particles possess many nanosized voids leading to large surface area (the highest is 145m2/g). Theevaluation results in some model reactions show that the SRNA series catalysts have 2 to 4 times higheractivity and selectivity than conventional Raney Ni catalyst for the hydrogenation of compounds with unsatur-ated functional groups. At present, the SRNA series catalysts have been successfully used in hydrogenation ofglucose, hydrogenation of pharmaceutical intermediates and purification of caprolactam. In order to use thesecatalysts efficiently, a magnetically stabilized bed (MSB) technology has been developed by combining theferromagnetic property of the catalyst with the good mass transfer characteristics of MSB. The demonstrationunit of MSB hydrogenation technology has been set up and has kept running for 2800 hours. The results showthat, after running 2800 hours, the catalyst still retained good activity; meanwhile, the hydrogenation effi-ciency had been improved 10 times in comparison with the traditional CSTR process.

  5. 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

  6. 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.

  7. Carbon-supported platinum alloy catalysts for phenol hydrogenation for making industrial chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, S.T.; Song, C.

    1999-07-01

    Phenol is available in large quantities in liquids derived from coal and biomass. Phenol hydrogenation is an industrially important reaction to produce cyclohexanone and cyclohexanol. Cyclohexane, cyclohexene and benzene are obtained as minor products in this reaction. Cyclohexanone is an important intermediate in the production of caprolactam for nylon 6 and cyclohexanol for adipic acid production. In USA, cyclohexanol and cyclohexanone are produced by benzene hydrogenation to cyclohexane over nickel or noble metal catalysts, followed by oxidation of cyclohexane to produce a mixture of cyclohexanol and cyclohexanone. Then cyclohexanol is dehydrogenated in the presence of Cu-Zn catalyst to cyclohexanone. Usually phenol hydrogenation is also carried out by using Ni catalyst in liquid phase. However, a direct single-step vapor phase hydrogenation of phenol to give cyclohexanone selectively is more advantageous in terms of energy savings and process economics, since processing is simplified and the endothermic step of cyclohexanol dehydrogenation can be avoided, as demonstrated by Montedipe and Johnson Matthey using promoted Pd/Al{sub 2}O{sub 3} catalyst. While it is not the purpose of this paper to dwell on the relative merits of these routes, it is necessary to mention that while using monometallic catalysts, generally the problem of catalyst deactivation of sintering as well as coking is frequently encountered. Addition and alloying of noble metal (e.g. Pt) with a second metal can result in a catalyst with better selectivity and activity in the reaction which is more resistant to deactivation. This paper presents the results on the single-step vapor phase hydrogenation of phenol over carbon-supported Pt-M (M=Cr, V, Zr) alloy catalysts to yield mainly cyclohexanone or cyclohexanol.

  8. 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.

  9. 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.

  10. 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.

  11. Cavitation-aided grain refinement in aluminium alloys

    NARCIS (Netherlands)

    Atamanenko, T.V.

    2010-01-01

    This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the conditi

  12. 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...

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Catalysts for oxidation of mercury in flue gas

    Science.gov (United States)

    Granite, Evan J.; Pennline, Henry W.

    2010-08-17

    Two new classes of catalysts for the removal of heavy metal contaminants, especially mercury (Hg) from effluent gases. Both of these classes of catalysts are excellent absorbers of HCl and Cl.sub.2 present in effluent gases. This adsorption of oxidizing agents aids in the oxidation of heavy metal contaminants. The catalysts remove mercury by oxidizing the Hg into mercury (II) moieties. For one class of catalysts, the active component is selected from the group consisting of iridium (Ir) and iridum-platinum (Ir/Pt) alloys. The Ir and Ir/Pt alloy catalysts are especially corrosion resistant. For the other class of catalyst, the active component is partially combusted coal or "Thief" carbon impregnated with Cl.sub.2. Untreated Thief carbon catalyst can be self-activating in the presence of effluent gas streams. The Thief carbon catalyst is disposable by means of capture from the effluent gas stream in a particulate collection device (PCD).

  2. Pd-Au bimetallic catalysts: understanding alloy effects from planar models and (supported) nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Feng; Goodman, Wayne D.

    2012-12-21

    Pd-Au bimetallic catalysts often display enhanced catalytic activities and selectivities compared with Pd-alone catalysts. This enhancement is often caused by two alloy effects, i.e., ensemble and ligand effects. The ensemble effect is dilution of surface Pd by Au. With increasing surface Au coverages, contiguous Pd ensembles disappear and isolated Pd ensembles form. For certain reactions, for example vinyl acetate synthesis, this effect is responsible for reaction rate enhancement via the formation of highly active surface sites, e.g., isolated Pd pairs. The disappearance of contiguous Pd ensembles also switches off side reactions catalyzed by these sites. This explains selectivity increase of certain reactions, for example direct H2O2 synthesis. The ligand effect is electronic perturbation of Au to Pd. By direct charge transfer or affecting bond length, the ligand effect causes the Pd d band to be more filled and the d-band center away from the Fermi level. Both changes make Pd more "atomic like" therefore binding reactants and products weaker. For certain reactions, this eliminates the so-called "self poisoning" and enhances activity/selectivity.

  3. 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.

  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. 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)

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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 pr......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 Zn...... 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...

  11. 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 pro......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 Zn...... 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...

  12. Preparation of low-platinum-content platinum-nickel, platinum-cobalt binary alloy and platinum-nickel-cobalt ternary alloy catalysts for oxygen reduction reaction in polymer electrolyte fuel cells

    Science.gov (United States)

    Li, Mu; Lei, Yanhua; Sheng, Nan; Ohtsuka, Toshiaki

    2015-10-01

    A series of low-platinum-content platinum-nickel (Pt-Ni), platinum-cobalt (Pt-Co) binary alloys and platinum-nickel-cobalt (Pt-Ni-Co) ternary alloys electrocatalysts were successfully prepared by a three-step process based on electrodeposition technique and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. Kinetics of ORR was studied in 0.5 M H2SO4 solution on the Pt-Ni, Pt-Co and Pt-Ni-Co alloys catalysts using rotating disk electrode technique. Both the series of Pt-Ni, Pt-Co binary alloys and the Pt-Ni-Co ternary alloys catalysts exhibited an obvious enhancement of ORR activity in comparison with pure Pt. The significant promotion of ORR activities of Pt-Ni and Pt-Co binary alloys was attributed to the enhancement of the first electron-transfer step, whereas, Pt-Ni-Co ternary alloys presented a more complicated mechanism during the electrocatalysis process but a much more efficient ORR activities than the binary alloys.

  13. Performance of metal alloys as hydrogen evolution reaction catalysts in a microbial electrolysis cell

    NARCIS (Netherlands)

    Jeremiasse, A.W.; Bergsma, J.; Kleijn, J.M.; Saakes, M.; Buisman, C.J.N.; Cohen Stuart, M.A.; Hamelers, H.V.M.

    2011-01-01

    H2 can be produced from organic matter with a microbial electrolysis cell (MEC). To decrease the energy input and increase the H2 production rate of an MEC, a catalyst is used at the cathode. Platinum is an effective catalyst, but its high costs stimulate searching for alternatives, such as non-nobl

  14. 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  

  15. 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

  16. 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.

  17. 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.)

  18. 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.

  19. L-S mass transfer in G-L-S countercurrent magnetically stabilized bed with amorphous alloy SRNA-4 catalyst

    Institute of Scientific and Technical Information of China (English)

    Wei; Li; Baoning; Zong; Xiaofang; Li; Xiangkun; Meng; Jinli; Zhang

    2007-01-01

    Liquid-solid (L-S) mass transfer coefficients (Ks) were characterized in a gas-liquid-solid (G-L-S) three-phase countercurrent magnetically stabilized bed (MSB) using amorphous alloy SRNA-4 as the solid phase. Effects of superficial liquid velocity, superficial gas velocity, magnetic field strength, liquid viscosity and surface tension were investigated. Experimental results indicated that the external magnetic field increased Ks in three-phase MSB, as compared to those in conventional G-L-S fluidized beds; that Ks increased with magnetic field strength, superficial gas and liquid velocities and decreased with liquid viscosity and surface tension; and that Ks showed uniform axial and radial distributions except for small increases close to the wall. Dimensionless correlations were established to estimate Ks of the G-L-S countercurrent MSB using SRNA-4catalyst, with an average error of 3.6%.

  20. 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.

  1. 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.

  2. 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...

  3. Reducing the Cost and Preserving the Reactivity in Noble-Metal-Based Catalysts: Oxidation of CO by Pt and Al-Pt Alloy Clusters Supported on Graphene.

    Science.gov (United States)

    Koizumi, Kenichi; Nobusada, Katsuyuki; Boero, Mauro

    2016-04-01

    The oxidation mechanisms of CO to CO2 on graphene-supported Pt and Pt-Al alloy clusters are elucidated by reactive dynamical simulations. The general mechanism evidenced is a Langmuir-Hinshelwood (LH) pathway in which O2 is adsorbed on the cluster prior to the CO oxidation. The adsorbed O2 dissociates into two atomic oxygen atoms thus promoting the CO oxidation. Auxiliary simulations on alloy clusters in which other metals (Al, Co, Cr, Cu, Fe, Ni) replace a Pt atom have pointed to the aluminum doped cluster as a special case. In the nanoalloy, the reaction mechanism for CO oxidation is still a LH pathway with an activation barrier sufficiently low to be overcome at room temperature, thus preserving the catalyst efficiency. This provides a generalizable strategy for the design of efficient, yet sustainable, Pt-based catalysts at reduced cost. PMID:26878836

  4. 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.

  5. 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.

  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

    One of the main challenges associated with the electrochemical CO or CO2 reduction is poor selectivity toward energetically rich products. In order to promote selectivity toward hydrocarbons and alcohols, most notably, the hydrogen evolution reaction (HER) should be suppressed. To achieve this goal...... 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. 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.

  8. Fracture performance of computer-aided manufactured zirconia and alloy crowns

    NARCIS (Netherlands)

    M. Rosentritt; M. Behr; C. Thaller; H. Rudolph; A.J. Feilzer

    2009-01-01

    Objective: To compare the fracture resistance and fracture performance of CAD/CAM zirconia and alloy crowns. Method and Materials: One electrophoretic deposition alumina ceramic (Wolceram, Wolceram) and 4 zirconia-based systems (ce.novation, ce.novation; Cercon, DeguDent; Digizon, Amann Girrbach; an

  9. Alternative alloys for catalysts and platinum jewelry? New structures in Pt-Hf and Pt-Mo

    Science.gov (United States)

    Gilmartin, Erin; Corbitt, Jacqueline; Hart, Gus

    2009-03-01

    The only known intermetallic structure with an 8:1 stoichiometry is that of Pt8Ti. It is intriguing that an ordered phase would occur at such low concentrations of the minority atom, but this structure occurs in about a dozen binary intermetallic systems. The formation of an ordered phase in an alloy can significantly enhance the performance of the material, particularly the hardness. We have taken a broad look at possible systems where this phase forms. Using first-principles, we calculated the stability of this structure relative to experimentally known phases for more than 80 Pt/Pd binary systems. We find the Pt8Ti structure is a possible ground state in more than 20 cases. Our experimental collaborators have verified our prediction in Pt-Mo and observed order-hardening in Pt-Hf. We discuss the discovery of new ground states that are likely to be verified experimentally and their impact on materials for Pt- and Pd-based catalysts and jewelry.

  10. 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.

  11. 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

  12. Nanostructured Fe(III) catalysts for water oxidation assembled with the aid of organic acid salt electrolytes

    Science.gov (United States)

    Zhao, Qiang; Li, Dandan; Gao, Guofeng; Yuan, Wen; Hao, Genyan; Li, Jinping

    2016-11-01

    We describe the preparation of three partially ordered iron-based catalyst films (Fe-OAc, Fe-Pro, Fe-But) with nanoporous structure by electrodeposition from organate electrolytes containing Fe2+. The anions of the organic acids assisted the partial ordering of the nanostructured Fe(III) catalysts for water oxidation. A model involving an electrical double layer is invoked to explain the role of the organate electrolyte system in their formation. Analytical results have revealed the main component of the iron-based films to be a β-FeOOH structure. The Fe-But catalyst catalyzed water oxidation in 0.1 m potassium carbonate solution with an average activity of 1.48 mA cm-2 and an overpotential of 433 mV.

  13. 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).

  14. Families as catalysts for peer adherence support in enhancing hope for people living with HIV/AIDS in South Africa

    Directory of Open Access Journals (Sweden)

    Caroline Masquillier

    2014-04-01

    Full Text Available Introduction: Hope is an essential dimension of successful coping in the context of illnesses such as HIV/AIDS, because positive expectations for the future alleviate emotional distress, enhance quality of life and have been linked to the capacity for behavioural change. The social environment (e.g. family, peers is a regulator of hope for people living with HIV/AIDS (PLWHA. In this regard, the dual aim of this article is (1 to analyze the influence of a peer adherence support (PAS intervention and the family environment on the state of hope in PLWHA and (2 to investigate the interrelationship between the two determinants. Methods: The Effective AIDS Treatment and Support in the Free State study is a prospective randomized controlled trial. Participants were recruited from 12 public antiretroviral treatment (ART clinics across five districts in the Free State Province of South Africa. Each of these patients was assigned to one of the following groups: a control group receiving standard care, a group receiving additional biweekly PAS or a group receiving PAS and nutritional support. Latent cross-lagged modelling (Mplus was used to analyse the impact of PAS and the family environment on the level of hope in PLWHA. Results: The results of the study indicate that neither PAS nor the family environment has a direct effect on the level of hope in PLWHA. Subsequent analysis reveals a positive significant interaction between family functioning and PAS at the second follow-up, indicating that better family functioning increases the positive effect of PAS on the state of hope in PLWHA. Conclusions: The interplay between well-functioning families and external PAS generates higher levels of hope, which is an essential dimension in the success of lifelong treatment. This study provides additional insight into the important role played by family dynamics in HIV/AIDS care, and it underscores the need for PAS interventions that are sensitive to the contexts in

  15. 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.

  16. 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.

  17. 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

  18. 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)

  19. 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...

  20. High-performance core-shell PdPt@Pt/C catalysts via decorating PdPt alloy cores with Pt

    Science.gov (United States)

    Wu, Yan-Ni; Liao, Shi-Jun; Liang, Zhen-Xing; Yang, Li-Jun; Wang, Rong-Fang

    A core-shell structured low-Pt catalyst, PdPt@Pt/C, with high performance towards both methanol anodic oxidation and oxygen cathodic reduction, as well as in a single hydrogen/air fuel cell, is prepared by a novel two-step colloidal approach. For the anodic oxidation of methanol, the catalyst shows three times higher activity than commercial Tanaka 50 wt% Pt/C catalyst; furthermore, the ratio of forward current I f to backward current I b is high up to 1.04, whereas for general platinum catalysts the ratio is only ca. 0.70, indicating that this PdPt@Pt/C catalyst has high activity towards methanol anodic oxidation and good tolerance to the intermediates of methanol oxidation. The catalyst is characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The core-shell structure of the catalyst is revealed by XRD and TEM, and is also supported by underpotential deposition of hydrogen (UPDH). The high performance of the PdPt@Pt/C catalyst may make it a promising and competitive low-Pt catalyst for hydrogen fueled polymer electrolyte membrane fuel cell (PEMFC) or direct methanol fuel cell (DMFC) applications.

  1. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

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

  2. Electrochemical Characteristics of LaNi4.5Al0.5 Alloy Used as Anodic Catalyst in a Direct Borohydride Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    Lianbang Wang; Guobin Wu; Zhenzhen Yang; Yunfang Gao; Xinbiao Mao; Chun'an Ma

    2011-01-01

    Fuel cells using borohydride as the fuel have received much attention because of high energy density and theoretical working potential. In this work, LaNi4.5Al0.5 hydrogen storage alloy used as the anodic material has been investigated. It was found that the increasing; operation temperature was helpful to the open-circuit potential, the discharge potential and the power density, but showed a negative effect on the utilization of the fuel due to the accelerated hydrogen evolution. The high KOH concentration was favorable for high-rate discharge capability. The adsorption and transformation of hydrogen on LaNi4.5Al0.5 alloy electrode has been observed, but its contribution to the discharge capability during a high-rate discharge was small.

  3. 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.

  4. 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.

  5. 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…

  6. 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.

  7. Combined high-pressure cell-ultrahigh vacuum system for fast testing of model metal alloy catalysts using scanning mass spectrometry

    DEFF Research Database (Denmark)

    Johansson, Martin; Jørgensen, Jan Hoffmann; Chorkendorff, Ib

    2004-01-01

    and gas sampling device over the sample surface. The gas sampled is analyzed with mass spectrometry. Experiments can be made at pressures up to 1 bar and temperatures up to 500 °C. It is shown that the lateral resolution is better than 0.2 mm and that up to 20 circular spots, 1 mm in diameter, can...... techniques available are scanning electron microscopy, x-ray photoemission spectroscopy, ion scattering spectroscopy, Auger electron spectroscopy, sputter profiling, and temperature programmed desorption. The catalytic activity of the model catalysts is tested individually by scanning a combined gas delivery...... be studied on a substrate 10 mm in diameter. A high pressure cell with an all-metal sealed ultrahigh vacuum lock is also described as part of the work. ©2004 American Institute of Physics....

  8. 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

  9. Urchin-Like Amorphous Ni2B Alloys: Efficient Antibacterial Materials and Catalysts for Hydrous Hydrazine Decomposition to Produce H2.

    Science.gov (United States)

    Deng, Miao; Fu, Shi Yan; Yang, Fan; Wu, Ping; Tong, Dong Ge

    2016-03-01

    Urchin-like amorphous Ni2B alloys were successfully prepared for the first time from a mixture of Ni(NH3)6(2+) and polyvinyl alcohol (PVA) via a solution plasma process (SPP). The as-synthesized samples were characterized by X-ray powder diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES) X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), selected-area electron diffraction patterns (SAED) and nitrogen adsorption-desorption isotherms. In the performance test, the obtained Ni-B urchins showed great antibacterial activities, comparable with those of amikacin and kanamycin, especially towards Pseudomonas aeruginosa (P. aeruginosa). Meanwhile, the magnetic properties of Ni-B urchins are enhanced in comparison with those of conventional Ni-B. During hydrous hydrazine (N2H4) decomposition, the dehydrogenation performance of Ni-B urchins is superior to those of Raney Ni and conventional Ni-B. The enhanced catalytic performance of Ni-B urchins is attributed to their high surface area of active species nickel and the enhanced intrinsic activity resulting from their unique structure. PMID:27455647

  10. 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.

  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...

  12. 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 ...

  13. 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.

  14. 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.

  15. 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 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...

  16. 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...

  17. Catalyst composition

    Energy Technology Data Exchange (ETDEWEB)

    Onodera, T.; Sakai, T.; Sumitani, K.; Yamasaki, Y.

    1984-11-27

    A catalyst composition comprising a crystalline aluminosilicate selected from the group consisting of zeolite ZSM-5, zeolite ZSM-11, zeolite ZSM-12, zeolite ZSM-35 and zeolite ZSM-38 and having a silica/alumina mole ratio of 20 to 1,000; and at least two metals which are platinum and at least one other metal selected from the group consisting of titanium, chromium, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, palladium, tin, barium, cerium, tungsten, osmium, lead, cadmium, mercury, indium, lanthanum and beryllium. This catalyst composition is useful particularly for the isomerization of aromatic hydrocarbons and reforming of naphtha.

  18. 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.

  19. 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. ...

  20. 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 ...

  1. 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 combinatio...... meaningful for everyone. The exhibited works are designed by SANAA, Diller Scofidio + Renfro, James Corner Field Operation, JBMC Arquitetura e Urbanismo, Atelier Bow-Wow, Ateliers Jean Nouvel, COBE, Transform, BIG, Topotek1, Superflex, and by visual artist Jane Maria Petersen....

  2. Study of ultrasonic vibration aided laser injection magnesium alloy solidification structure%超声振幅对激光熔注镁合金凝固组织的研究

    Institute of Scientific and Technical Information of China (English)

    赵明娟; 邓志成; 赵龙志; 张坚

    2015-01-01

    Based on the CA method,a grain growth model for simulation of microstructure evolution was estab-lished,and the influence of grain growth of magnesium alloy melt with different amplitude of ultrasonic vibra-tion was studied in this paper.The results show that with the increase of ultrasonic amplitude,melt undercoo-ling increases as power function,when the melt of undercooling was very small,the melt uncleats hardly,while the undercooling reaches a certain value,the nucleation rate increases dramatically.When amplitude was 10 μm,the undercooling induced by ultrasonic vibration was 32.23 K,and the nucleation rate for the melt was 353 times that of the melt without ultrasonic vibration.Under the ultrasonic vibration the alloy melt undercoo-ling increases,the melt nucleation rate increases,the grain size becomes smaller and more uniform.The simula-tion results are well in agreement with experimental results,which ensure that the simulation can guide the ap-plication of laser injection aided by ultrasonic vibration in industrial production.%采用 CA 法建立了镁合金晶粒生长模型,研究了超声振动作用下镁合金熔体的晶粒生长。结果表明,随着超声振幅的增大,熔体过冷度呈幂函数增大,熔体在过冷度很小时,基本不形核,达到一定值时,形核率急剧增加。当振幅达到10μm 时,超声振动提高的过冷度达到32.23 K,镁合金熔体形核率为未施加超声的353倍。超声振动的引入增大了合金熔体的过冷度,提高了熔体形核率,凝固组织平均晶粒尺寸减小,组织分布更均匀。模拟结果与试验结果相符,说明该模拟可以指导超声振动在辅助激光熔注工业生产中的应用。

  3. PROPERTIES OF POLYMER SUPPORTED Ni-Cu BIMETALLIC CATALYSTS PREPARED BY SOLVATED METAL ATOM IMPREGNATION

    Institute of Scientific and Technical Information of China (English)

    WU Shihua; ZHU Changying; HUANG Wenqiang

    1996-01-01

    D-72 resin supported nickel-copper catalysts prepared by solvated metal atom impregnation (SMAI) were studied by magnetic measurements and X-ray photoelectron spectroscopy (XPS). The Ni particles on the catalysts are very highly dispersed and display superparamagnetic behaviour. Ni-Cu alloy clusters were found to be formed. The surface compositions are different from the bulk concentrations. In contrast with the surface enrichment in copper generally observed on conventional Ni-Cu catalysts, the surfaces of these catalysts are enriched in nickel. The nickel is in both zero and valent states, while copper is mainly in metallic state. Catalytic data show that the formation of Ni-Cu alloy clusters has a profound effect on the catalytic activities of the catalysts in the hydrogenation of furfural. The activity of the Ni:Cu ratio of one bimetallic catalysts is much higher than that of the Ni or Cu monometallic catalyst.

  4. 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 ...

  5. 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...

  6. 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.

  7. 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.

  8. 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 ...

  9. 微波辅助雷尼镍-铝合金催化剂催化1,4-二氯苯快速脱氯反应动力学研究%In-situ Rapid Dechlorination by Microwave-assisted Catalytic Reduction of Chlorobenzene and 1,4-dichlorobenzene on Raney Ni-Al alloy Catalyst

    Institute of Scientific and Technical Information of China (English)

    陈志明; 莫招育; 吕保樱; 谢鸿; 唐丽; 林华

    2013-01-01

    Microwave-assisted catalytic rednctive dechlorination on Raney Ni-Al alloy catalyst is an efficient method for chlorobenzene (CB) and 1,4-dichlorobenzene (1,4-DCB) treatment. The result showed that the Raney Ni-Al alloy catalyst retains its high activity in this in-situ reductive dechlorination reaction. This reductive dechlorination reaction was in accordance of the psendo-second-order reaction kinetics under microwave irradiation. The activation energy (Ea) was 76.24 kj/mol. And the constant of 1,4-DCB dechlorination was 0.037 6 (35 ℃ ) and 0.151 mol/(L · min) (50 ℃) , and the activation energy (Ea) was 76. 66 kj/mol. Rapid and complete dechlorination which was achieved for CB and 1,4-DCB was obtained at close to ambient conditions. And it was showed that microwave-assisted catalytic in-situ reductive dechlorination on Raney Ni-Al alloy catalyst was an effective method to rapid and complete dechlorination for polychlorinated organic compounds.%利用雷尼镍-铝合金催化剂的高催化活性,提出了使用微波辅助雷尼镍-铝合金催化1,4-二氯苯还原脱氯的方法.结果表明,在微波辅助雷尼镍-铝合金催化剂条件下,1,4-二氯苯还原脱氯的反应符合二级反应动力学方程.1,4-二氯苯脱氯的反应速率常数k1在35和50℃下分别为0.037 6和0.151 mol/(L·min),反应活化能为76.66 kJ/mol.研究还表明,在微波辅助雷尼镍-铝合金催化剂的条件下,35℃时,1,4-二氯苯10 min脱氯率达到90%,并且反应同时脱掉两个氯,能达到高效脱氯的目的.由此可知,微波辅助雷尼镍-铝合金催化脱氯的方法应用于多氯苯类物质脱氯取得良好的效果.

  10. 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.

  11. Hearing Aid

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A man realized that he needed to purchase ahearing aid, but he was unwilling to spend muchmoney. "How much do they run?"he asked theclerk. "That depends," said. the salesman. "Theyrun from 2 to 2000."

  12. 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 ...

  13. Electrochemical catalyst recovery method

    Science.gov (United States)

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

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

  14. Platinum and Palladium Alloys Suitable as Fuel Cell Electrodes

    DEFF Research Database (Denmark)

    2011-01-01

    and innovative catalyst compositions in fuel cell electrodes. The novel electrode catalysts of the invention comprise a noble metal selected from Pt, Pd and mixtures thereof alloyed with a further element selected from Sc, Y and La as well as any mixtures thereof, wherein said alloy is supported on a conductive......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...

  15. Determination of platinum in Adam's catalyst

    Directory of Open Access Journals (Sweden)

    Anđelić Brankica Č.

    2003-01-01

    Full Text Available Adams's catalyst PtO2 x H2O has an important application in the chemical industry. The method for determination of platinum in Adam's catalyst has been elaborated. It includes the combination of cupellation and gravimetry methods. Considering that platinum oxide is practically insolvent in mineral acids, the sample is alloyed with lead by cupellation method and the separated balls solution procedure has been tested. The ball, platinum and lead alloy, is soluble in mineral acid. The platinum was settled by amonium chloride from solution, and obtained deposit treated by amonium acetate with addition of ethanol for lead removing. The retained platinum was determined by atomic absorption spctrophotometry method in the filtrate (after the platinum separation and the final result of platinum content corrected. It was shown how the combined gravimetric and AAS-Pt determination methods might be used for solving determination of Pt content in practically unsoluble sample of catalyst. Applied procedure enables testing the catalyst quality and proving its characteristics required for chemical industry.

  16. 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.

  17. 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 ...

  18. 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.

  19. 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...... which investigated the strategies these states have adopted in talks with aid donors, the sources of leverage they have been able to bring to bear in negotiations, and the differing degrees of control that they have been able to exercise over the policies agreed in negotiations and those implemented...

  20. 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.

  1. 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

  2. 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...

  3. 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.

  4. 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.

  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. 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.

  7. 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)

  8. 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.

  9. 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 ...

  10. Fabrication and evaluation of nickel cobalt alloy electrocatalysts for alkaline water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Hoon [School of Integrative Engineering, Chung-Ang University, Heukseokno 84, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Ahn, Sang Hyun; Choi, Insoo [Fuel Cell Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Pyo, Sung Gyu [School of Integrative Engineering, Chung-Ang University, Heukseokno 84, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Kim, Hyoung-Juhn; Jang, Jong Hyun [Fuel Cell Research Center, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Kim, Soo-Kil, E-mail: sookilkim@cau.ac.kr [School of Integrative Engineering, Chung-Ang University, Heukseokno 84, Dongjak-gu, Seoul 156-756 (Korea, Republic of)

    2014-07-01

    As a catalyst for the hydrogen evolution reaction (HER) in alkaline water splitting, NiCo alloys of various compositions were prepared through electrodeposition onto Cu substrates. The composition of each alloy catalyst was varied by controlling the molar ratio of Co{sup 2+} ions in the electrolyte. With an increase in the Co content, the morphologies of the NiCo alloys were progressively changed from a round to polygonal shape. The NiCo alloys all exhibited a Ni rich surface, as confirmed by the bulk-to-surface compositional ratio and degree of alloying. The catalytic activities of the NiCo alloys toward the HER of water splitting were electrochemically tested in a KOH electrolyte, and the specific activities were characterized by considering the electrochemical surface areas of Ni and Co. The effect of alloying was demonstrated to be a significant enhancement of HER activity, resulting from a change in the electronic structures of Ni and Co.

  11. 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.

  12. 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...

  13. Polyol synthesis of highly active PtRu/C catalyst with high metal loading

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shiyou; Sun, Gongquan; Tian, Juan; Jiang, Luhua; Qi, Jing; Xin, Qin [Direct Alcohol Fuel Cell Laboratory, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian (China)

    2006-12-01

    Highly loaded PtRu/C catalyst with high activity toward methanol electrooxidation was synthesized via a modified polyol process. XRD patterns indicated that the prepared catalyst was highly alloyed and TEM results showed that the metal nanoparticles were small and uniformly distributed on the carbon support despite the high metal loading. EDX results suggested that the two metals distributed uniformly in the catalyst. Electrochemical characterization and single cell test jointly showed that the prepared 40-20wt.%PtRu/C catalyst possessed high activity toward methanol electrooxidation. (author)

  14. 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

  15. 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.

  16. Robust CoAl Alloy: Highly Active, Reusable and Green Catalyst in the Hydrogenolysis of Glycerol%Robust CoAl Alloy: Highly Active, Reusable and Green Catalyst in the Hydrogenolysis of Glycerol

    Institute of Scientific and Technical Information of China (English)

    郭晓洋; 尹安远; 郭晓东; 郭秀英; 戴维林; 范康年

    2011-01-01

    CoAl alloy catalyst is found, for the first time, to be highly active, selective and reusable for the synthesis of diols via the hydrogenolysis of glycerol under mild conditions. The products and the catalyst could be self-separated from the reaction system through a simple reactor.

  17. 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.

  18. 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).

  19. 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.

  20. 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].

  1. 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.

  2. 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.

  3. 以非晶态合金催化剂SRNA-4为固相的气液固磁稳定床的界面传质研究%Interphase Mass Transfer in G-L-S Magnetically Stabilized Bed with Amorphous Alloy SRNA-4 Catalyst

    Institute of Scientific and Technical Information of China (English)

    李(韦华); 宗保守; 李晓芳; 孟祥坤; 张金利

    2006-01-01

    Gas-liquid (G-L) and liquid-solid (L-S) mass transfer coefficients were characterized in a gas-liquid-solid(G-L-S) three-phase magnetically stabilized bed (MSB) using amorphous alloy SRNA-4 as the solid phase. Effects such as superficial liquid velocity, superficial gas velocity, magnetic strength, liquid viscosity, and particle size were investigated. Experimental results indicated that the G-L volumetric mass transfer coefficients (KLa) increased along with the magnetic strength, superficial gas and liquid velocities. Proper increase of liquid viscosity promoted KLa only in the range of lower liquid viscosity. The external magnetic field made L-S mass transfer coefficients (Ks)in the G-L-S MSB lower than those of conventional fluidized beds. Ks in the MSB almost kept constant as the superficial liquid velocity and superficial gas velocity increased and decreased with the liquid viscosity and surface tension, while increased with the particle size Ks showed uniform axial and radial distributions except of small decreases close to the wall. Dimensionless correlations were established to estimate KLa and Ks of the MSB with SRNA-4 catalysts, which showed the average error of 5.4% and 2.5% respectively.

  4. The Capabilities of the Foamed Amorphous Alloy Catalyst for th e Hydrogenation of Benzene%发泡非晶态合金对苯加氢的催化性能

    Institute of Scientific and Technical Information of China (English)

    牛玉舒; 李保山; 全明秀; 胡壮麒

    2001-01-01

    采用新型发泡非晶态Ni-P合金催化剂,在微型固定床连续反应器上进行了苯加氢制 备环己烷的实验研究。结果表明:这种新型发泡非晶态合金催化剂具有较好的加氢催化活性 和很好的选择性,在体系氢压为2.0 MPa、反应温度为300 ℃,苯的进料速率为3 mL/h的条 件下 ,环己烷的单程收率为33.28%。试验考察了该催化剂的稳定性,结果表明,在360 h内,其 催化 活性没有显著变化。另外,该催化剂具有很好的通透性,催化剂层前、后几乎无压差。试验 还发现,该催化剂没有明显的诱导期,无需经过预处理就有很好的加氢催化活性。因此,发 泡非晶态Ni-P催化剂有希望成为工业催化剂。%Using the novel foamed amorphous alloy-fo amed Ni-P alloy-as catal yst, the hydrogenation of benzene to cyclohexane was carried out in a minisize c atena fix-bed reactor. The products were analyzed by gas chromatograph. Through t he experiments, the suitable processing conditions were obtained as the followi ng:the re action temperature 300 ℃, the feed rate 3 mL/h and the pressure of the system 2 .0 MPa. Under these conditions, the selectivity of hexamethylene alkyl was nearl y 1 00 % and the yield was about 33.28%. The results of the research on the stability indicated that the activity didn't change much in 360 h. In addition, the catal y st has no obvious inducement time. It has a good hydrogenation activity dispense with pretreatment. So the foamed Ni-P amorphous alloy can be used as industry cata lyst.

  5. AIDS.gov

    Science.gov (United States)

    ... concerns. Search Services Share This Help National HIV/AIDS Strategy Check out NHAS's latest progress in the ... from AIDS.gov Read more AIDS.gov tweets AIDS.gov HIV/AIDS Basics • Federal Resources • Using New ...

  6. 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,...

  7. 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...

  8. 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.

  9. Studies on PEM Fuel Cell Noble Metal Catalyst Dissolution

    DEFF Research Database (Denmark)

    Ma, Shuang; Skou, Eivind Morten

    Incredibly vast advance has been achieved in fuel cell technology regarding to catalyst efficiency, improvement of electrolyte conductivity and optimization of cell system. With breathtakingly accelerating progress, Proton Exchange Membrane Fuel Cells (PEMFC) is the most promising and most widely....... 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...

  10. 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.

  11. Magnetic catalyst bodies

    NARCIS (Netherlands)

    Teunissen, Wendy; Bol, A.A.; Geus, John W.

    2001-01-01

    After a discussion about the importance of the size of the catalyst bodies with reactions in the liquid-phase with a suspended catalyst, the possibilities of magnetic separation are dealt with. Deficiencies of the usual ferromagnetic particles are the reactivity and the clustering of the particles.

  12. 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...

  13. 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...

  14. 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 ...

  15. 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: ...

  16. 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 ...

  17. 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 ...

  18. 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 ...

  19. 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.

  20. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    . Previously it has been shown that calcination of cobalt catalyst in a NO/He mixture resulted in improved catalytic activity compared to standard air calcined samples, since more homogenous cobalt particles with a narrow particle size distribution were formed. Unfortunately the C5+ selectivity decreased....... Since Mn is known to improve C5+ selectivity the addition of this promoter, combined with NO calcination, was studied. The influence of parameters such as Co:Mn ratio, drying conditions, and reduction temperatures on the catalytic performance were investigated. The promotion strategy 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 vanadium-based catalyst...

  1. 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.

  2. 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)

  3. 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.

  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. 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.

  6. 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

  7. 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.

  8. ALKALI RESISTANT CATALYST

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

  9. 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.

  10. 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...

  11. 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...

  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...... 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 categorize some of the key goals, principles and institutions of the aid system. The evidence on whether aid has...... for aid in the future...

  13. 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....

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. STUDIES ON HYDROISOMERIZATION CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    C5/C6 alkane hydroisomerization is one of the most economical technologies for octane enhancement and has potential application in China in the next decade. The work about choice of hydroisomerization catalyst systems and scale-up in catalyst preparation was presented. Performance and regeneration behaviors tested in different laboratory reactors and a 1000 t/a pilot plant were discussed, which offers the information for commercial use of this process. Mechanism for coke formation was also proposed.

  20. New Catalysts for ROMP

    Institute of Scientific and Technical Information of China (English)

    H. Berke; C. Frech; A. Lhamazares; O. Blacque; H.W. Schmalle; C. Adlhart; P. Chen

    2005-01-01

    @@ 1Introduction Ring Opening Metathesis Polymerization (ROMP) is based on the olefin metathesis reaction, which requires transition metal catalysts. Mainly molybdenum, tungsten and ruthenium based catalysts have up to now been used. The "in-between" metal rhenium was only rarely applied in olefin metathesis reactions, and not at all in ROMP processes.We have found that cationic phosphine substituted dinitrosyl rhenium complexes[1]1a and 1b effectively catalyze ROMP of norbonene, dicyclopentadiene and of cyclooctene. See Fig. 1.

  1. 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 ...

  2. 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

  3. 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.

  4. Evaluation of luminol chemiluminescence based on simultaneous introducing of coumarin derivatives as green fluorophores and chitosan-induced Au/Ag alloy nanoparticle as catalyst for the sensitive determination of glucose.

    Science.gov (United States)

    Chaichi, M J; Alijanpour, S O; Asghari, S; Shadlou, S

    2015-03-01

    We report herein the development of a novel chemiluminescence system based on simultaneous introducing of synthetic coumarin derivatives and chitosan-induced Au/Ag alloy NPs on the luminol CL system and suggest how it may be useful for determination of glucose. Chitosan-induced Au/Ag nanoalloys in the coumarin derivatives intensified-luminol CL system, in addition to catalyze CL reaction can make a change in the process of coumarin derivatives effect as fluorophore on the luminol CL system. This phenomenon is caused by interaction between active functional groups of coumarin derivatives and chitosan. The interaction strength depends on the coumarin derivatives' structure and their substituents. Considering the inevitable trend luminol radical and superoxide anion radical to absorption on the surface of the embedded Au/Ag nanoalloy in the chitosan matrix, it can be concluded that chitosan acts as a platform for all reagents involved in the CL reaction including coumarin derivatives, Au/Ag nanoalloy and luminol, and electron-transfer taking place on it; Placing all chemiluminescent reagents together on the chitosan network can lead to a powerful CL due to increasing rigidity of CL system. The most efficient coumarin derivative on the Au/Ag nanoalloy-fluorophore-luminol-H2O2 CL system, in relation to interaction capability with chitosan' functional groups, was selected and the CL condition in presence of it was optimized. Whereas the glucose oxidase-mediated oxidation of glucose yields gluconic acid and H2O2, under optimum condition the most efficient CL system was applied to detection of glucose due to enzymatically production of hydrogen peroxide. The linear response range of 1.5 × 10(-6)-5.0 × 10(-3) M and the detection limit (defined as the concentration that could be detected at the signal-to-noise ratio of 3) of 7.5 × 10(-7) M was found for the glucose standards. Also, the developed method was successfully applied to determination of glucose in

  5. New catalysts for coal processing: Metal carbides and nitrides

    Energy Technology Data Exchange (ETDEWEB)

    S. Ted Oyama; David F. Cox

    1999-12-03

    The subject of this research project was to investigate the catalytic properties of a new class of materials, transition metal carbides and nitrides, for treatment of coal liquid and petroleum feedstocks. The main objectives were: (1) preparation of catalysts in unsupported and supported form; (2) characterization of the materials; (3) evaluation of their catalytic properties in HDS and HDN; (4) measurement of the surface properties; and (5) observation of adsorbed species. All of the objectives were substantially carried out and the results will be described in detail below. The catalysts were transition metal carbides and nitrides spanning Groups 4--6 in the Periodic Table. They were chosen for study because initial work had shown they were promising materials for hydrotreating. The basic strategy was first to prepare the materials in unsupported form to identify the most promising catalyst, and then to synthesize a supported form of the material. Already work had been carried out on the synthesis of the Group VI compounds Mo{sub 2}C, Mo{sub 2}N, and WC, and new methods were developed for the Group V compounds VC and NbC. All the catalysts were then evaluated in a hydrotreating test at realistic conditions. It was found that the most active catalyst was Mo{sub 2}C, and further investigations of the material were carried out in supported form. A new technique was employed for the study of the bulk and surface properties of the catalysts, near edge x-ray absorption spectroscopy (NEXAFS), that fingerprinted the electronic structure of the materials. Finally, two new research direction were explored. Bimetallic alloys formed between two transition metals were prepared, resulting in catalysts having even higher activity than Mo{sub 2}C. The performance of the catalysts in hydrodechloration was also investigated.

  6. 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

  7. 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.

  8. 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...

  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. 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.

  11. 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...

  12. 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 ...

  13. 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 ...

  14. 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.

  15. 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 ...

  16. 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: ...

  17. 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 ...

  18. 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 ...

  19. 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 ...

  20. 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 ...

  1. 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, ...

  2. 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 ...

  3. 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 ...

  4. 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 ...

  5. 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 ...

  6. 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 ...

  7. 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 ...

  8. 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 ...

  9. 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 ...

  10. 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 ...

  11. A durable PtRu/C catalyst with a thin protective layer for direct methanol fuel cells.

    Science.gov (United States)

    Shimazaki, Yuzuru; Hayasaka, Sho; Koyama, Tsubasa; Nagao, Daisuke; Kobayashi, Yoshio; Konno, Mikio

    2010-11-15

    A methanol oxidation catalyst with improved durability in acidic environments is reported. The catalyst consists of PtRu alloy nanoparticles on a carbon support that were stabilized with a silane-coupling agent. The catalyst was prepared by reducing ions of Pt and Ru in the presence of a carbon support and the silane-coupling agent. The careful choice of preparatory conditions such as the concentration of the silane-coupling agent and solution pH resulted in the preparation of catalyst in which the PtRu nanoparticles were dispersively adsorbed onto the carbon support. The catalytic activity was similar to that of a commercial catalyst and was unchanged after immersion in sulfuric acid solution for 1000 h, suggesting the high durability of the PtRu catalyst for the anode of direct methanol fuel cells.

  12. Non-metallic catalysts for diamond synthesis under high pressure and high temperature

    Institute of Scientific and Technical Information of China (English)

    孙力玲; 吴奇; 戴道扬; 张君; 秦志成; 王文魁

    1999-01-01

    Recent results on conversion from graphite to diamond by aid of non-metallic catalysts are reviewed. The current status of experimental advances is presented and typical examples from relevant literature are provided for understanding the mechanism of the graphite-diamond conversion by aid of these non-metallic catalysts. Furthermore, a tendency of graphite-diamond transformation assisted by carbonates, sulfates or phosphorus under high pressure and high temperature has been investigated by calculating the activation energy and transformation probability of the carbon atoms over a potential barrier. It was found that the activation energy is highly sensitive to the catalyst chosen. The probability sequence of graphite-diamond transformation with these catalysts was put forward.

  13. Music and Hearing Aids

    OpenAIRE

    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 a...

  14. 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...

  15. 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 ...

  16. Fuel cell electrocatalsis : oxygen reduction on Pt-based nanoparticle catalysts

    NARCIS (Netherlands)

    Vliet, Dennis Franciscus van der

    2010-01-01

    The thesis contains a discussion on the subject of the Oxygen Reduction Reaction (ORR) on Pt-alloy nanoparticle catalysts in the Rotating Disk Electrode (RDE) method. An insight in some of the difficulties of this method is given with proper solutions and compensations for these problems. Pt3Co, Au-

  17. Determinants of State Aid

    NARCIS (Netherlands)

    Buiren, K.; Brouwer, E.

    2010-01-01

    From economic theory we derive a set of hypotheses on the determination of state aid. Econometric analysis on EU state aid panel data is carried out to test whether the determinants we expect on the basis of theory, correspond to the occurrence of state aid in practice in the EU. We find that politi

  18. 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 ...

  19. 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) ...

  20. 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! ...

  1. 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 ...

  2. 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: ...

  3. 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 ...

  4. 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 ...

  5. Designing State Aid Formulas

    Science.gov (United States)

    Zhao, Bo; Bradbury, Katharine

    2009-01-01

    This paper designs a new equalization-aid formula based on fiscal gaps of local communities. When states are in transition to a new local aid formula, the issue of whether and how to hold existing aid harmless poses a challenge. The authors show that some previous studies and the formulas derived from them give differential weights to existing and…

  6. 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)

  7. Olefin metathesis catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S.G.; Banks, R.L.

    1986-05-20

    A process is described for preparing a disproportionation catalyst comprising admixing a catalytically effective amount of a calcined and activated catalyst consisting essentially of at least one metal oxide selected from molybdenum oxide and tungsten oxide and a support containing a major proportion of silica or alumina with a promoting amount of a methylating agent selected from the group consisting of dimethyl sulfate, dimethylsulfoxide, trimethyloxonium tetrafluorborate, methyl iodide, and methyl bromide, and subjecting same to inert atmospheric conditions for the methylating agent to promote the activity of the calcined molybdenum and tungsten oxides for the disproportionation of olefins.

  8. Aerogel derived catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, J. G., LLNL

    1996-12-11

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

  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. 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...

  11. 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

  12. 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...... 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 treating an catalyst for conferring thereon an improved resistance to alkali poisoning....

  13. Nanoporous PdCo Catalyst for Microfuel Cells: Electrodeposition and Dealloying

    Directory of Open Access Journals (Sweden)

    Satoshi Tominaka

    2011-01-01

    Full Text Available PdCo alloy is a promising catalyst for oxygen reduction reaction of direct methanol fuel cells because of its high activity and the tolerance to methanol. We have applied this catalyst in order to realize on-chip fuel cell which is a membraneless design. The novel design made the fuel cells to be flexible and integratable with other microdevices. Here, we summarize our recent research on the synthesis of nanostructured PdCo catalyst by electrochemical methods, which enable us to deposit the alloy onto microelectrodes of the on-chip fuel cells. First, the electrodeposition of PdCo is discussed in detail, and then, dealloying for introducing nanopores into the electrodeposits is described. Finally, electrochemical response and activities are fully discussed.

  14. Computer-Aided Modelling Methods and Tools

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    The development of models for a range of applications requires methods and tools. In many cases a reference model is required that allows the generation of application specific models that are fit for purpose. There are a range of computer aided modelling tools available that help to define....... To illustrate these concepts a number of examples are used. These include models of polymer membranes, distillation and catalyst behaviour. Some detailed considerations within these models are stated and discussed. Model generation concepts are introduced and ideas of a reference model are given that shows...... a taxonomy of aspects around conservation, constraints and constitutive relations. Aspects of the ICAS-MoT toolbox are given to illustrate the functionality of a computer aided modelling tool, which incorporates an interface to MS Excel....

  15. 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.

  16. 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...... 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 categorize some of the key goals, principles and institutions of the aid system. The evidence on whether 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...

  17. 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....

  18. 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.

  19. Aid and Development

    DEFF Research Database (Denmark)

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

    This paper considers the relationship between external aid and development in Mozambique from 1980 to 2004. The main objective is to identify the specific mechanisms through which aid has influenced the developmental trajectory of the country and whether one can plausibly link outcomes to aid...... 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...... 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...

  20. Metal alloy identifier

    Science.gov (United States)

    Riley, William D.; Brown, Jr., Robert D.

    1987-01-01

    To identify the composition of a metal alloy, sparks generated from the alloy are optically observed and spectrographically analyzed. The spectrographic data, in the form of a full-spectrum plot of intensity versus wavelength, provide the "signature" of the metal alloy. This signature can be compared with similar plots for alloys of known composition to establish the unknown composition by a positive match with a known alloy. An alternative method is to form intensity ratios for pairs of predetermined wavelengths within the observed spectrum and to then compare the values of such ratios with similar values for known alloy compositions, thereby to positively identify the unknown alloy composition.

  1. 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.

  2. Olefin metathesis and catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S. G.; Banks, R. L.

    1985-05-14

    Olefins are converted into other olefins having different numbers of carbon atoms by contact with a catalyst comprising an inorganic refractory oxide support containing at least one of tungsten oxide and molybdenum oxide and a promoting amount of at least one methylating agent under conditions suitable for the methylating agent compounds to promote the activity of tungsten and molybdenum oxides for the disproportionation reaction.

  3. 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

  4. 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...

  5. Nanopore and nanoparticle catalysts.

    Science.gov (United States)

    Thomas, J M; Raja, R

    2001-01-01

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

  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. Surface Structure and Catalytic Performance of Ni-Fe Catalyst for Low-Temperature CO Hydrogenation

    Directory of Open Access Journals (Sweden)

    Fanhui Meng

    2014-01-01

    Full Text Available Catalysts 16NixFe/Al2O3 (x is 0, 1, 2, 4, 6, 8 were prepared by incipient wetness impregnation method and the catalytic performance for the production of synthetic natural gas (SNG from CO hydrogenation in slurry-bed reactor were studied. The catalysts were characterized by BET, XRD, UV-Vis DRS, H2-TPR, CO-TPD, and XPS, and the results showed that the introduction of iron improved the dispersion of Ni species, weakened the interaction between Ni species and support and decreased the reduction temperature and that catalyst formed Ni-Fe alloy when the content of iron exceeded 2%. Experimental results revealed that the addition of iron to the catalyst can effectively improve the catalytic performance of low-temperature CO methanation. Catalyst 16Ni4Fe/Al2O3 with the iron content of 4% exhibited the best catalytic performance, the conversion of CO and the yield of CH4 reached 97.2% and 84.9%, respectively, and the high catalytic performance of Ni-Fe catalyst was related to the property of formed Ni-Fe alloy. Further increase of iron content led to enhancing the water gas shift reaction.

  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. Challenges for new electro catalysts development for the ORR in acid medium for PEM fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Savadogo, O. [Ecole Polytechnique, Montreal, PQ (Canada). Laboratory of New Materials for Electrochemistry and Energy

    2010-07-01

    The low kinetic rate at the oxygen reduction reaction (ORR) of platinum (Pt) electrocatalysts in acid mediums is one of the most limiting factors for the industrial mass production of proton exchange membrane fuel cells (PEMFCs). New electrocatalyst materials are currently being investigated by researchers as a replacement for Pt include lignited ruthenium-based chalcogenides; pyrolized iron (Fe) porphyrins; metal carbides; and molybdenum (Mo), iridium (Ir) and cobalt (Co) based catalysts. Co-polypyrrole is also being considered as a non-noble catalyst. This presentation discussed the main parameters that limit the ORR of non-noble catalysts in PEMFC applications. Palladium (Pa) based bi-metallic alloys were investigated. The study showed that Pd-alloy catalysts exhibit excellent activity for the ORR in acidic media. The highest electrocatalytic activity was demonstrated in an alloy composition of 60 per cent Pd. The cost of Pd was compared to the cost of Pt. The intrinsic metal surface properties of Pd-alloys were also discussed, and the onset potential of the ORR was compared for various alloys. 31 refs., 1 tab.

  10. 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

  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. Aid and Growth

    DEFF Research Database (Denmark)

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

    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......, 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 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....

  13. 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 difference...

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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

  19. Music and Hearing Aids

    Directory of Open Access Journals (Sweden)

    Sara M. K. Madsen

    2014-10-01

    Full Text Available 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.

  20. 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

  1. Music and hearing aids.

    Science.gov (United States)

    Madsen, Sara M K; Moore, Brian C J

    2014-10-31

    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.

  2. Fluorination process using catalysts

    Science.gov (United States)

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

    1983-08-25

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

  3. Fluorination process using catalyst

    Science.gov (United States)

    Hochel, Robert C.; Saturday, Kathy A.

    1985-01-01

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

  4. 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...

  5. Preparation of nanometer FeCuP alloy and its application in decomposition of PH3

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH3 was prepared with low-cost material by chemical reduction deposition method. The properties of it were characterized by XRD, ICP and SEM. Its catalytic activity on the decomposition of PH3 and the decomposition conditions were studied. FeCuP alloy exhibits high thermal stabilities and high catalytic activity. Using it as catalyst, the decomposition temperature of phosphine decreases from over 800 ℃ to 400-500 ℃. The decomposition rate of phosphine achieved 100%.

  6. Olefin metathesis and catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kukes, S. G.; Banks, R. L.

    1985-03-12

    Olefins are converted into other olefins having different numbers of carbon atoms by contact with a catalyst comprising an inorganic refractory material containing at least one of tungsten oxide and molybdenum oxide and a promoting amount of at least one treating agent selected from chlorinated silicon compounds, thionyl chloride, and sulfuryl chloride under conditions suitable for the treating agent to promote the activity of tungsten and molybdenum oxides for the disporoportionation reaction.

  7. High-Performance Pd3Pb Intermetallic Catalyst for Electrochemical Oxygen Reduction.

    Science.gov (United States)

    Cui, Zhiming; Chen, Hao; Zhao, Mengtian; DiSalvo, Francis J

    2016-04-13

    Extensive efforts to develop highly active and strongly durable electrocatalyst for oxygen reduction are motivated by a need for metal-air batteries and fuel cells. Here, we report a very promising catalyst prototype of structurally ordered Pd-based alloys, Pd3Pb intermetallic compound. Such structurally ordered Pd3Pb/C exhibits a significant increase in mass activity. More importantly, compared to the conventional Pt/C catalysts, ordered Pd3Pb/C is highly durable and exhibits a much longer cycle life and higher cell efficiency in Zn-air batteries. Interestingly, ordered Pd3Pb/C possesses very high methanol tolerance during electrochemical oxygen reduction, which make it an excellent methanol-tolerant cathode catalyst for alkaline polymer electrolyte membrane fuel cells. This study provides a promising route to optimize the synthesis of ordered Pd-based intermetallic catalysts for fuel cells and metal-air batteries. PMID:26848634

  8. Mechanical alloying in immiscible alloy systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In recent years, mechanical alloying (MA) of immiscible alloy systems characterized by positive heat of mixing has been extensively investigated. The present article reviews the latest progress in MA of immiscible alloy systems including the mechanisms of non-equilibrium phase transformation and metastable phase formation of the MA-driven supersaturated solid solutions, amorphous phases and nanophase composites as well as their mechanical and physical properties related to those metastable phases.

  9. 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

  10. 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

  11. Catalyst composition and impurity-dependent kinetics of nanowire heteroepitaxy.

    Science.gov (United States)

    Gamalski, Andrew D; Perea, Daniel E; Yoo, Jinkyoung; Li, Nan; Olszta, Matthew J; Colby, Robert; Schreiber, Daniel K; Ducati, Caterina; Picraux, S Tom; Hofmann, Stephan

    2013-09-24

    The mechanisms and kinetics of axial Ge-Si nanowire heteroepitaxial growth based on the tailoring of the Au catalyst composition via Ga alloying are studied by environmental transmission electron microscopy combined with systematic ex situ CVD calibrations. The morphology of the Ge-Si heterojunction, in particular, the extent of a local, asymmetric increase in nanowire diameter, is found to depend on the Ga composition of the catalyst, on the TMGa precursor exposure temperature, and on the presence of dopants. To rationalize the findings, a general nucleation-based model for nanowire heteroepitaxy is established which is anticipated to be relevant to a wide range of material systems and device-enabling heterostructures.

  12. Catalyst Composition and Impurity-dependent Kinetics of Nanowire Heteroepitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Gamalski, A. D.; Perea, Daniel E.; Yoo, Jinkyoung; Li, N.; Olszta, Matthew J.; Colby, Robert J.; Schreiber, Daniel K.; Ducati, C.; Picraux, Samuel T.; Hofmann, S.

    2013-08-05

    The mechanisms and kinetics of axial Ge-Si nanowire heteroepitaxial growth based on the tailoring of the Au catalyst composition via Ga alloying are studied by environmental transmission electron microscopy combined with systematic ex-situ CVD calibrations. The morphology of the Ge-Si heterojunction, in particular the extent of a local, asymmetric increase in nanowire diameter, is found to depend on the Ga composition of the catalyst, on the TMGa precursor exposure temperature, and on the presence of dopants. To rationalize the findings, a general nucleation-based model for nanowire heteroepitaxy is established which is anticipated to be relevant to a wide range of material systems and device-enabling heterostructures.

  13. 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).

  14. 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.

  15. 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

  16. 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].

  17. AIDS as Metaphor.

    Science.gov (United States)

    McMillen, Liz

    1994-01-01

    Scholarly interest in Acquired Immune Deficiency Syndrome (AIDS) has spread throughout the humanities, attracting the attention of historians of medicine, political scientists, sociologists, public health scholars, and anthropologists. Most theorists hope their research will aid in policymaking or change understanding of the epidemic. (MSE)

  18. [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

  19. 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…

  20. 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.

  1. 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 c...

  2. 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....

  3. 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…

  4. 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.

  5. 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.

  6. 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.

  7. Catalyst systems and uses thereof

    Science.gov (United States)

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

    2012-07-24

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

  8. 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.

  9. 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.

  10. In silico search for novel methane steam reforming catalysts

    DEFF Research Database (Denmark)

    Xu, Yue; Lausche, Adam C; Wang, Shengguang;

    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 ‘Cat......, 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...

  11. In situ investigation of catalysts for alcohol synthesis

    DEFF Research Database (Denmark)

    Duchstein, Linus Daniel Leonhard; Sharafutdinov, Irek; Wu, Qiongxiao;

    microscopic and macroscopic properties of materials, e.g. relating catalytic performance with crystal structure and morphology. This study presents extensive characterization of NiGa and CuNi alloys during catalyst formation, alcohol synthesis, and accelerated aging experiments. The characterization platform...... consists of three complimentary in situ techniques: (1) Activity measurements based on a reactor connected to a gas chromatograph (GC), (2) In situ x-ray diffractometer (XRD) measurements based on a reactor cell connected to a mass spectrometer (MS), and (3) environmental TEM (ETEM) that allows...

  12. 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.

  13. 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...

  14. 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.

  15. Atomic-level Electron Microscopy of Metal and Alloy Electrocatalysts

    DEFF Research Database (Denmark)

    Deiana, Davide

    This thesis presents the application of transmission electron microscopy techniques towards the characterisation of novel metal nanoparticle catalysts. Two main subjects have been covered: first, the sintering-resistance behaviour of monomodal mass-selected Pt cluster catalysts have been studied...... by means of ex situ Scanning Transmission Electron Microscopy (STEM) in combination with in situ indirect nanoplasmonic sensing. Secondly, electron microscopy imaging and spectroscopy have been used for the characterisation of novel metal alloy nanoparticle electrocatalysts for the Oxygen Reduction...... and its dissolution into the electrolyte. The formed Pt-rich shell prevents further dissolution of the rare earth metal protecting the alloyed core. Pt−Hg and Pd−Hg have been identified by Density Functional Theory (DFT) calculations as promising candidates for the electrochemical production of hydrogen...

  16. Bimetallic Au-decorated Pd catalyst for the liquid phase hydrodechlorination of 2,4-dichlorophenol

    Science.gov (United States)

    Zhou, Juan; Chen, Huan; Chen, Quanyuan; Huang, Zhaolu

    2016-11-01

    Monometallic and bimetallic Pd-Au catalysts supported on multi-walled carbon nanotubes (CNTs) with varied Au cooperation amounts were prepared using the complexing-reduction method in the presence of tetrahydrofuran (THF). The liquid phase catalytic hydrodechlorination (HDC) of 2,4-dichlorophenol (2,4-DCP) was investigated over these bimetallic catalysts. The catalysts were characterized by N2 adsorption-desorption isotherms, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and H2 chemisorption. Characterization results showed that the co-reduction of Pd and Au mainly formed alloy-like structure. The bimetallic catalysts had smaller metal particles and larger numbers of exposed active site than that of monometallic catalysts. In addition, compared with Pd(1.7)/CNTs and Au(0.4)/CNTs, the binding energies of Pd 3d5/2 shifted to higher positions while that of Au 4f7/2 had negative shifts in the Pd-Au bimetallic catalysts, which can be ascribed to the electrons transferred from metal Pd to Au and the cationization of Pd particles was enhanced. Accordingly, the bimetallic Pd-Au particles with different Au contents in the catalysts exhibited varied synergistic effects for the catalytic HDC of 2,4-DCP, with Pd(1.8)Au(0.4)/CNTs having the highest catalytic activity. For the bimetallic catalysts, a disproportional increase of turnover frequency (TOF) was observed with increasing Au content due to the enhanced cationization of Pd particles. Moreover, the dechlorination of 2,4-DCP over the supported monometallic and bimetallic catalysts proceeded via both the stepwise and concerted pathway, and the concerted pathway became predominant with Au decoration amount in the catalyst.

  17. 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.

  18. PLUTONIUM-THORIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.

    1959-09-15

    New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.

  19. 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...

  20. REACTOR FILLED WITH CATALYST MATERIAL, AND CATALYST THEREFOR

    NARCIS (Netherlands)

    Sie, S.T.

    1995-01-01

    Abstract of WO 9521691 (A1) Described is a reactor (1) at least partially filled with catalyst granules (11), which is intended for catalytically reacting at least one gas and at least one liquid with each other. According to the invention the catalyst granules (11) are collected in agglomerates

  1. Catalyst regeneration by circulating catalyst in a hydrotreating oil process

    Energy Technology Data Exchange (ETDEWEB)

    Kanbier, D.; Goudriaan, F.

    1978-02-14

    A process is disclosed for catalytic hydrotreating of a heavy hydrocarbon oil and a light hydrocarbon oil in separate reactors, wherein the hydrotreating catalyst is circulated through both reactors. The process is particularly suited to obtaining long catalyst life when operating at low hydrogen pressures.

  2. 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.

  3. 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.

  4. Platinum and palladium nano-structured catalysts for polymer electrolyte fuel cells and direct methanol fuel cells.

    Science.gov (United States)

    Long, Nguyen Viet; Thi, Cao Minh; Yong, Yang; Nogami, Masayuki; Ohtaki, Michitaka

    2013-07-01

    In this review, we present the synthesis and characterization of Pt, Pd, Pt based bimetallic and multi-metallic nanoparticles with mixture, alloy and core-shell structure for nano-catalysis, energy conversion, and fuel cells. Here, Pt and Pd nanoparticles with modified nanostructures can be controllably synthesized via chemistry and physics for their uses as electro-catalysts. The cheap base metal catalysts can be studied in the relationship of crystal structure, size, morphology, shape, and composition for new catalysts with low cost. Thus, Pt based alloy and core-shell catalysts can be prepared with the thin Pt and Pt-Pd shell, which are proposed in low and high temperature proton exchange membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs). We also present the survey of the preparation of Pt and Pd based catalysts for the better catalytic activity, high durability, and stability. The structural transformations, quantum-size effects, and characterization of Pt and Pd based catalysts in the size ranges of 30 nm (1-30 nm) are presented in electro-catalysis. In the size range of 10 nm (1-10 nm), the pure Pt catalyst shows very large surface area for electro-catalysis. To achieve homogeneous size distribution, the shaped synthesis of the polyhedral Pt nanoparticles is presented. The new concept of shaping specific shapes and morphologies in the entire nano-scale from nano to micro, such as polyhedral, cube, octahedra, tetrahedra, bar, rod, and others of the nanoparticles is proposed, especially for noble and cheap metals. The uniform Pt based nanosystems of surface structure, internal structure, shape, and morphology in the nanosized ranges are very crucial to next fuel cells. Finally, the modifications of Pt and Pd based catalysts of alloy, core-shell, and mixture structures lead to find high catalytic activity, durability, and stability for nano-catalysis, energy conversion, fuel cells, especially the next large-scale commercialization of next

  5. 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

  6. 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. ...

  7. 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, ...

  8. 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 ...

  9. 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 ...

  10. 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 ...

  11. 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 ...

  12. 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.

  13. Hearing Aid and children

    Directory of Open Access Journals (Sweden)

    Jamileh Fatahi

    2002-07-01

    Full Text Available In order to develop oral communication, hearing impaired infants and young children must be able to hear speech comfortably and consistently. To day children with all degrees of hearing loss may be condidates for some kinds of amlification. As children differ from adults, many Factors should be consider in hearing aid selection, evaluation and fitting. For example the child age when he or she is candidate for custom instruments? Do we consider programmable Hearing aid? Are multi memory instruments appropriate for them? What about directional microphones? What style of hearing aid do we select? In this paper such questions are Answered.

  14. 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....

  15. 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....

  16. 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......) significant and positive in the tradable and the nontradable sectors, and (ii) equally strong in both sectors. The article thus provides no empirical support for the hypothesis that aid reduces external competitiveness in developing countries. A possible reason for this finding is the existence of large idle...

  17. 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....

  18. 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.

  19. deNOx catalysts for biomass combustion

    DEFF Research Database (Denmark)

    Kristensen, Steffen Buus

    industrial reference catalyst. Furthermore long-term activity measurements at normal operating temperature revealed that the catalyst did not display any sign of deactivation. The catalyst showed very high resistance towards potassium poisoning maintaining a 16 times higher activity than the equally poisoned...... industrial reference catalyst, after impregnation of 225 mole potassium/g of catalyst. A catalyst plate was synthesised using 20 wt.% sepiolite mixed with nano catalyst, supported by a SiO2-fibre mesh. Realistic potassium poisoning was performed on the catalyst plate, by exposure in a potassium aerosol...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  7. 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.)

  8. Active and Durable Hydrogen Evolution Reaction Catalyst Derived from Pd-Doped Metal-Organic Frameworks.

    Science.gov (United States)

    Chen, Jitang; Xia, Guoliang; Jiang, Peng; Yang, Yang; Li, Ren; Shi, Ruohong; Su, Jianwei; Chen, Qianwang

    2016-06-01

    The water electrolysis is of critical importance for sustainable hydrogen production. In this work, a highly efficient and stable PdCo alloy catalyst (PdCo@CN) was synthesized by direct annealing of Pd-doped metal-organic frameworks (MOFs) under N2 atmosphere. In 0.5 M H2SO4 solution, PdCo@CN displays remarkable electrocatalytic performance with overpotential of 80 mV, a Tafel slope of 31 mV dec(-1), and excellent stability of 10 000 cycles. Our studies reveal that noble metal doped MOFs are ideal precursors for preparing highly active alloy electrocatalysts with low content of noble metal.

  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. 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 ...

  11. 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

  12. 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+...

  13. 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)

  14. 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.

  15. 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...

  16. 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....

  17. 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

  18. 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.

  19. 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.

  20. 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...

  1. 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

  2. Stereospecific olefin polymerization catalysts

    Science.gov (United States)

    Bercaw, John E.; Herzog, Timothy A.

    1998-01-01

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

  3. 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

    for engineering of more active or selective catalyst materials. Dynamical surface changes on alloy surfaces due to the adsorption of reactants in high gas pressures are challenging to investigate using standard characterization tools. Here we apply synchrotron illuminated near ambient pressure X-ray photoelectron...

  4. 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

    of nanostructured Pt-Y alloy catalysts were studied using transmission electron microscopy techniques. Using elemental X-ray mapping and high-resolution electron microscopy, the specific compositional structure and distribution of the individual nanoparticles was unraveled and the stability assessed. Studying...

  5. 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]. Howev...

  6. Multilateral Aid | L’aide multilatérale

    Directory of Open Access Journals (Sweden)

    2012-05-01

    Full Text Available Bilateral and Multilateral Aid, DAC Members, 1960–2010 (in million USD constant, 2009Aide bilatérale et multilatérale des pays membres du CAD, 1960-2010 (en millions USD constants de 2009­Bilateral and Multilateral Aid by Recipient Region, DAC Members, 2008 (in percentage of total aid by RegionAide bilatérale et multilatérale des pays membres du CAD par region de destination, 2008 (en pourcentage de l’aide totale par régionSources: OECD (2010 2010 DAC Report on Multilateral Aid (Paris: O...

  7. 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

  8. 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

  9. 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)

  10. 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.

  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. An in-depth understanding of the bimetallic effects and coked carbon species on an active bimetallic Ni(Co)/Al2O3 dry reforming catalyst.

    Science.gov (United States)

    Liao, Xin; Gerdts, Rihards; Parker, Stewart F; Chi, Lina; Zhao, Yongxiang; Hill, Martyn; Guo, Junqiu; Jones, Martin O; Jiang, Zheng

    2016-06-29

    Ni/Al2O3, Co/Al2O3 and bimetallic Ni(Co)/Al2O3 catalysts were prepared using an impregnation method and employed in CO2 dry reforming of methane under coking-favored conditions. The spent catalysts were carefully characterized using typical characterization technologies and inelastic neutron scattering spectroscopy. The bimetallic catalyst exhibited a superior activity and anti-coking performance compared to Ni/Al2O3, while the most resistant to coking behavior was Co/Al2O3. The enhanced activity of the Ni(Co)/Al2O3 bimetallic catalyst is attributed to the reduced particle size of metallic species and resistance to forming stable filamentous carbon. The overall carbon deposition on the spent bimetallic catalyst is comparable to that of the spent Ni/Al2O3 catalyst, whereas the carbon deposited on the bimetallic catalyst is mainly less-stable carbonaceous species as confirmed by SEM, TPO, Raman and INS characterization. This study provides an in depth understanding of alloy effects in catalysts, the chemical nature of coked carbon on spent Ni-based catalysts and, hopefully, inspires the creative design of a new bimetallic catalyst for dry reforming reactions.

  13. 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.

  14. 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.

  15. 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 quantify...... and compare the different effects in the adsorption of acetylene and ethylene on various transition-metal surfaces (see picture)....

  16. 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...

  17. 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).

  18. 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

  19. 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)

  20. Computer aided materials design; Keisanki zairyo sekkei

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The questionnaire survey on the computer aided materials design (CAMD), and the survey of current domestic and overseas software concerned were carried out to clarify developmental issues. The current elementary technology of CAMD was also surveyed to study its several problems caused with a progress of material design technology due to drastic diffusion of CAMD. This project aims at establishment of a new demanded software, computer chemistry, focusing attention on functional materials such as catalyst, polymer and non-linear electronic materials. Microscopic simulation technology was mainly surveyed in fiscal 1996. Although some fruitful results have been obtained in the fields of medical and agricultural chemicals, organic compounds, proteins, catalysts and electronic materials, such some problems are pointed out as `CAMD cannot handle an actual size of the target system` and `commercially available software are very expensive.` Reliable tool development as elementary technology, and the verification of its applications are thus required. Meso-dynamics, polymers, surface reaction and integrated technological environment attract users` attention. 27 refs., 16 figs., 2 tabs.

  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. 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. PLUTONIUM-ZIRCONIUM ALLOYS

    Science.gov (United States)

    Schonfeld, F.W.; Waber, J.T.

    1960-08-30

    A series of nuclear reactor fuel alloys consisting of from about 5 to about 50 at.% zirconium (or higher zirconium alloys such as Zircaloy), balance plutonium, and having the structural composition of a plutonium are described. Zirconium is a satisfactory diluent because it alloys readily with plutonium and has desirable nuclear properties. Additional advantages are corrosion resistance, excellent fabrication propenties, an isotropie structure, and initial softness.

  4. 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.

  5. 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)

  6. 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

  7. 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

  8. 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...

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

    DEFF Research Database (Denmark)

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

    ] confirm dealloying as responsible for high temperature (T > 300 °C) deactivation, this does not explain the activity loss in the low temperature regime (T temperature (T = 200, 210, 250 °C) deactivation of silica supported Ni5Ga3 nanoparticles...... as 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 subsequently increased, suggesting the presence of carbon containing species blocking the active sites of the alloy nanoparticles (Figure 1). Carbon deposition has furthermore been investigated by temperature programmed oxidation (TPO) of a deactivated catalyst in a fixed-bed reactor connected to a mass...

  11. Investigation of altenative carbon materials for fuel-cell catalyst support

    DEFF Research Database (Denmark)

    Larsen, Mikkel Juul

    In order to ensure high utilization of the catalyst material in a polymer electrolyte membrane fuel cell (PEMFC) it is usually fixed in the form of nanoparticles on a supporting material. The catalyst is platinum or a platinum alloy, and the commonly used support is carbon black (CB). Although...... the large surface area and good anchoring properties make it a suited material for this purpose, it is prone to degradation in the fuel-cell environment. Thus alternative materials with higher durability than CB, but with similar (or better) capability of dispersion, are desired. Among them are highly...... structured carbon forms such as graphitized CBs, carbon nanotubes (CNTs), and carbon nanofibres (CNFs). This thesis concerns the investigation of an array of different materials which may prospec-tively replace the conventional materials used in the catalyst. The study comprised 13 carbon samples which...

  12. 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.

  13. 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.

  14. Copper containing hydrocarbon cracking catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lussier, R.J.; Magee, J.S. Jr.

    1975-12-30

    A copper-exchanged zeolite cracking catalyst capable of producing high octane gasoline of increased aromatic and olefinic content is described. Mixtures of copper and hydrogen ions are exchanged into a Y-type zeolite using a combination of exchange and calcination steps. The exchanged zeolite is advantageously combined with a major portion of inorganic oxide matrix to produce a catalyst suitable for use in standard commercial fluid and moving bed cat-cracking units. (auth)

  15. Mechanical Properties and Friction/Wear Behavior of Copper Alloyed Powder Composites

    Institute of Scientific and Technical Information of China (English)

    DENG Chen-hong; CHEN Guang-zhi; GE Qi-lu

    2005-01-01

    Copper alloyed powder composites containing nanoparticles were developed by hot pressing. Effects of nanoscale activated sintering aid and fine ceramic particles Al2O3 on hardness, working quality, and behaviors of friction and wear of the composites have been studied, compared with the composites including microscale activated sintering aid and microscale ceramic particles. The microstructures of the samples were analyzed by SEM. The results show that the materials with nanoscale sintering aid and fine ceramic particles have better mechanical properties and abrasive resistance than the materials with microscale activated sintering aid and microceramic particles. Moreover, element mutual transfer occurs between samples (strip) and abrasive wheel (ring).

  16. 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)

  17. 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

  18. 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.

  19. 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.

  20. The role of reaction pathways and support interactions in the development of high activity hydrotreating catalysts

    DEFF Research Database (Denmark)

    Topsøe, Henrik; Hinnemann, Berit; Nørskov, Jens Kehlet;

    2005-01-01

    exhibiting a metallic character are observed to be involved in adsorption, hydrogenation and C-S bond cleavage. The insight is seen to provide a new framework for understanding the DDS and HYD pathways and the role of steric hindrance and poisons. Density functional theory (DFT) calculations have illustrated...... structures may be present as single sulfide sheets. Thus, stacking is not an essential feature of Type II catalysts. The article illustrates how the new scientific insight has aided the introduction of the new high activity BRIM (TM) type catalysts for FCC pre-treatment and production of ultra low sulfur...

  1. Parent Hearing Aid Experiences

    Science.gov (United States)

    Munoz, Karen; Roberts, Mallory; Mullings, Day; Harward, Richard

    2012-01-01

    This study addresses parent experiences in obtaining and managing hearing aids for their young child. The purpose was to identify challenges parents encounter to determine what state agencies can do to improve parent access to amplification. Data were collected July through September of 2010; 40 parents of children ages birth to 3 years old…

  2. 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…

  3. 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

  4. 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…

  5. 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.

  6. 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

  7. 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.

  8. 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– ...

  9. 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

  10. 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.

  11. Coil Welding Aid

    Science.gov (United States)

    Wiesenbach, W. T.; Clark, M. C.

    1983-01-01

    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  12. 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.

  13. 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

  14. 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

  15. Screening for AIDS.

    Science.gov (United States)

    1985-03-29

    Tests to detect serum antibody to human T-lymphotropic virus type III (HTLV-III), based on an enzyme-linked immunosorbent assay (ELISA) that uses whole disrupted HTLV-III virus antigens, are now commercially available in the US. Recent surveys of groups at high risk for acquired immunodeficiency syndrome (AIDS) have found that 22-65% of homosexual men, 87% of active intravenous drug users, 56-72% of hemophiliacs, and 35% of women who were sexual partners of men with AIDS have had postitive ELISA tests compared with fewer than 1% of those with no known risk factors. A positive ELISA test could be due to subclinical infection, immunity, or cross-reactivity with other viral antigens. Laboratory error can also produce false positive results. Thus, it is recommended that the ELISA test be repeated at least once on all seropositive specimens before the result is reported to the patient. The western blot test appears to be more specific and less sensitive than the ELISA. Studies of asymptomatic seropositive homosexual men followed for 2-5 years have found that over 50% remain asymptomatic, 5-19% develop full blown AIDS, and 25% develop signs suggestive of the AIDS-related complex. Asymptomatic patients with positive ELISA tests should be made aware of early signs and symptoms of AIDS. Other data suggest that seropositive patients have the HTLV-III virus in their blood, semen, and/or saliva and can transmit the infection. Precautions to prevent transmission, such as the use of condoms, should be taken by such patients. Physicians should be sensitive to the fear and anxiety that a positive ELISA test will create.

  16. 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.

  17. Copper-tantalum alloy

    Science.gov (United States)

    Schmidt, Frederick A.; Verhoeven, John D.; Gibson, Edwin D.

    1986-07-15

    A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.

  18. 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

  19. 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)

  20. 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...

  1. 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.

  2. 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

  3. 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.

  4. 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)

  5. 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.

  6. 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.

  7. 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 ...

  8. 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- ...

  9. 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. ...

  10. Does Corruption Cause Aid Fatigue?

    DEFF Research Database (Denmark)

    Bauhr, Monika; Charron, Nicholas; Nasiritousi, Naghmeh

    2013-01-01

    Does perceived corruption in recipient countries reduce support for foreign aid in donor countries? This under-explored yet salient question is examined using the 2009 Eurobarometer survey for the 27 EU countries. We suggest that perceived corruption can cause aid fatigue but that this relationship...... is highly contextualized. The results show that perceptions about corruption in developing countries reduce overall support for aid among respondents in donor countries. However, this effect is mitigated by country and contextual-level effects and different understandings of what we call the “aid......-corruption paradox,” namely that the need for foreign aid is often the greatest in corrupt environments. Three different dynamics of the aid-corruption paradox influence support for aid: moral, pragmatic, and strategic understandings. In EU-15 countries, the effect of perceived corruption in recipient states on aid...

  11. 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 ...

  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

    Energy Technology Data Exchange (ETDEWEB)

    Christ, F.; Steudel, H.; Klotz, D.

    1986-02-01

    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.

  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. Mycobacterial Infections in AIDS

    Directory of Open Access Journals (Sweden)

    A Ross Hill

    1991-01-01

    Full Text Available Tuberculosis (TB remains uniquely important among acquired immune deficiency syndrome (AIDS-associated opportunistic infections: it presents the greatest public health hazard worldwide, is the most readily curable, and is largely preventable with existing means. Given the expanding pool of human immunodeficiency virus (HIV seropositive persons, particularly in developing nations where Mycobacterium tuberculosis remains a leading health problem, one can expect a continued rise in TB cases during the 1990s. Global efforts to eliminate TB are now inextricably entwined with the effectiveness of measures to curtail the HIV epidemic. Mycobacterium avium complex infection, currently an intractable late complication of aids, may increase in clinical importance as success in managing other opportunistic infections and HIV disease itself improves. Understanding of the pathogenesis and management of mycobacterial diseases should increase rapidly given the renewed research spurred on by the advent of HIV.

  17. 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 ...

  18. 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 ...

  19. 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

  20. 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

  1. 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.

  2. 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....

  3. AIDS and Occupational Therapy

    Directory of Open Access Journals (Sweden)

    Ruiz Garrós, MC

    2004-12-01

    Full Text Available "When my first hospitalization took place, I must recognize I was plunged into the mistake of identifying AIDS with death, together with the depression, uneasiness, unsecurity and the feeling of inability to plan my life in the short and long term to the point of refusing in my mind to organize things as simple as future holidays or improvements at home".Thanks to retroviral treatments, the initially mortal HIV/AIDS infection has become a chronic disease as it can be today thediabetes, allowing objectives in the short, medium and long term. Here is where the occupational therapy operates as an instrument to improve, keep or rehabilitate the occupational areas of this group which has a series of special features to be borne in mind when working with them.I seek to reflect my 8 months experience working as an occupational therapist in a Refuge Centre for AIDS ill people, and how throughout this experience I changed several of my initial approaches and working methods too.

  4. Redirecting British foreign aid.

    Science.gov (United States)

    Dean, M

    1994-01-01

    Britain has longed followed a disease-control strategy for providing aid in the health sector to developing, low-income countries. Given, however, the high level of waste upon tertiary care and specialized medicine in current health programs of low-income countries as documented by the World Bank; the poor performance of existing general government hospitals and clinics; and the poor image of Third World health systems in the eyes of Western officials and government ministers, the chief health advisor of the Overseas Development Administration has called for a drastic redirection of policy toward development aid. Specifically, a shift away from a specific-disease control approach toward an overall, sweeping reform of the health sector in developing countries is urged. The level of waste needs to be reduced and more attention given to the poor. Unless such changes result, government ministers will grow increasingly reluctant to provide tangible aid to the health sectors of countries in need. The availability of such funds invested in effective, well-managed health programs will grow more critical to health in the Third World as populations shift away from communicable disease morbidity and mortality toward illnesses which are of a more noncommunicable nature such as stroke and cancer.

  5. 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.

  6. Electro-oxidation of ethylene glycol on nanoporous Ti-Cu amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Chen Cuijie [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhu Shengli, E-mail: slzhu@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Yang Xianjin [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Pi Lele; Cui Zhenduo [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2011-11-30

    Highlights: > Nanoporous Ti-Cu amorphous alloy exhibits apparent EG electrocatalytic ability EG electro-oxidation occurs more easily in alkaline medium than in acid medium. > In acid medium, heat treatment plays an enhancing role towards EG oxidation. > In alkaline medium, heat treatment has opposite effect below and above 0.1 V. - Abstract: This work describes ethylene glycol (EG) electro-oxidation over nanoporous structure catalyst prepared by dealloying Ti-Cu amorphous alloy. Scanning electron microscopy (SEM) was used to characterize nanoporous catalysts. Electrocatalytic performances in acid and alkaline mediums were measured by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The results showed that nanoporous Ti-Cu amorphous alloy exhibited apparent electrocatalytic ability in terms of higher oxidation current in CV and CA curves comparing to raw Ti-Cu amorphous alloy. Electro-oxidation of EG took place more easily in alkaline medium than that in acid medium. In acid medium, heat treatment improved the electrocatalytic activity of nanoporous catalyst. In alkaline medium, heat treatment played an enhancing role below 0.1 V and a depressing role above 0.1 V. Possible electro-oxidation mechanism of EG was also discussed.

  7. 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.

  8. 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.

  9. Corrosion Behaviour of Zn-10Al-1.5Cu Alloy

    Directory of Open Access Journals (Sweden)

    C. N. Panagopoulos

    2011-01-01

    Full Text Available The corrosion behaviour of Zn-10Al-1.5Cu alloy in NaCl solution was examined. The used NaCl solution concentrations were 1M, 0.3M, and 0.003M for a constant temperature values of 7°C or 25°C or 45°C. The corrosion behaviour of this alloy was investigated under potentiodynamic corrosion conditions. The surface of the corroded alloy specimens was studied with the aid of scanning electron microscopy and X-ray diffraction techniques. It was observed that the increase of NaCl concentration in the corrosion solution for a constant value of temperature led to lower corrosion resistance of the alloy. For a constant value of solution concentration, the increase of solution temperature also led to the decrease of corrosion resistance of the same alloy.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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...

  15. 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

  16. Single-Atom Catalyst of Platinum Supported on Titanium Nitride for Selective Electrochemical Reactions.

    Science.gov (United States)

    Yang, Sungeun; Kim, Jiwhan; Tak, Young Joo; Soon, Aloysius; Lee, Hyunjoo

    2016-02-01

    As a catalyst, single-atom platinum may provide an ideal structure for platinum minimization. Herein, a single-atom catalyst of platinum supported on titanium nitride nanoparticles were successfully prepared with the aid of chlorine ligands. Unlike platinum nanoparticles, the single-atom active sites predominantly produced hydrogen peroxide in the electrochemical oxygen reduction with the highest mass activity reported so far. The electrocatalytic oxidation of small organic molecules, such as formic acid and methanol, also exhibited unique selectivity on the single-atom platinum catalyst. A lack of platinum ensemble sites changed the reaction pathway for the oxygen-reduction reaction toward a two-electron pathway and formic acid oxidation toward direct dehydrogenation, and also induced no activity for the methanol oxidation. This work demonstrates that single-atom platinum can be an efficient electrocatalyst with high mass activity and unique selectivity.

  17. One-step synthesis of PtPdAu ternary alloy nanoparticles on graphene with superior methanol electrooxidation activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuzhen; Gu Yonge; Lin Shaoxiong; Wei Jinping; Wang Zaihua [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Wang Chunming, E-mail: wangcm@lzu.edu.cn [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Du Yongling; Ye Weichun [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

    2011-10-01

    Highlights: > PtPdAu nanoparticles were synthesized on graphene sheets via chemical reduction method. > The prepared PtPdAu nanoparticles were ternary alloy with fcc structure. > The catalyst exhibited superior catalytic activity and stability for MOR in alkaline. - Abstract: Well-dispersed PtPdAu ternary alloy nanoparticles were synthesized on graphene sheets via a simple one-step chemical reduction method in ethylene glycol (EG) and water system, in which EG served as both reductive and dispersing agent. The electrocatalytic activity of PtPdAu/G was tested by methanol oxidation reaction (MOR). The catalyst was further characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), which indicated that the as-synthesized PtPdAu nanoparticles with alloy structures were successfully dispersed on the graphene sheets. Electrocatalytic properties of the catalyst for MOR in alkaline have been investigated by cyclic voltammetry (CV), chronoamperometry and Tafel curves. The electrocatalytic activity and stability of PtPdAu/G were superior to PtPd/G, PtAu/G and Pt/G. In addition, the anodic peak current on PtPdAu/G catalyst was proportional to the concentration of methanol in the range of 0.05-1.00 M. This study implies that the prepared catalyst have great potential applications in fuel cells.

  18. Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

    Standard Specification for Copper-Aluminum-Silicon-Cobalt Alloy, Copper-Nickel-Silicon-Magnesium Alloy, Copper-Nickel-Silicon Alloy, Copper-Nickel-Aluminum-Magnesium Alloy, and Copper-Nickel-Tin Alloy Sheet and Strip

  19. Efficient epoxidation of propene using molecular catalysts

    DEFF Research Database (Denmark)

    Markovits, Iulius I. E.; Anthofer, Michael H.; Kolding, Helene;

    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...

  20. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  1. 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.

  2. 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...

  3. 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

  4. 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

  5. Refractory alloy component fabrication

    International Nuclear Information System (INIS)

    Purpose of this report is to describe joining procedures, primarily welding techniques, which were developed to construct reliable refractory alloy components and systems for advanced space power systems. Two systems, the Nb-1Zr Brayton Cycle Heat Receiver and the T-111 Alloy Potassium Boiler Development Program, are used to illustrate typical systems and components. Particular emphasis is given to specific problems which were eliminated during the development efforts. Finally, some thoughts on application of more recent joining technology are presented. 78 figures

  6. Machining of titanium alloys

    CERN Document Server

    2014-01-01

    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  7. 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

  8. 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...

  9. [Adolescence and AIDS].

    Science.gov (United States)

    1991-01-01

    The myths and prejudices that distort the reality and hide the true causes and effects of natural and social phenomena related to sexuality have a fertile ground in AIDS, given its obvious link to sex. The alarming spread of AIDS has been 1 result of these myths and prejudices. Human beings are sexual by nature; genital organs determine sex and also induce sexual behavior. It is by not fairly well accepted that an individual's sexuality exists from birth. Puberty usually begins at 12-16 years for both sexes. The physical changes of puberty terminate in the ability of the female to conceive and the male to procreate. The sexual excitation of adolescents resulting from production of various hormones can only be eliminated by some type of sexual satisfaction or sublimation. Sexuality, according to Freud, is an organizing principle of the personality. The sexual organs exist not merely for reproduction but to provide pleasure. Puberty signifies entry into active sex life. But the ideological structure of society, perpetuated by the family, schools, religion, the mass media, and other social institutions, sends confused signals to adolescents, requiring abstinence and virginity until marriage for women while encouraging sexual adventures for men. Adolescents are confronted by their new sexual feelings in the midst of a virtual bombardment of visual sexual stimuli from the mass media. It becomes impossible for adolescents to satisfy the requirements of appearances while also resolving the problems and pressures of their newly gained sexual maturity. Many adolescents become sexually active, and the problem is not to prevent sexual activity but to improve the conditions under which it occurs. Adolescents, lacking education and information about sex, begin their sex lives without protection. AIDS has now been added to the list of dire consequences that can result. A true sex education beginning in the home is needed to enable young people to develop healthy and full sex

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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...... heated” debate on aid needs redirecting toward more rigorous analysis, in which the advantages—and disadvantages—of using aid for development can be evaluated in a calmer manner....

  15. [Women and AIDS in Africa].

    Science.gov (United States)

    Coll Seck, A M

    1990-10-01

    The theme of "World Aids Day" for 1990 was "Women and AIDS." This theme was chosen because of the devastating effects AIDS has on women. The World Health Organization's (WHO) latest figures state that women represent 1/3 of the estimated 6 million people infected with AIDS worldwide. The majority of these women are in Sub-Saharan Africa (SSA) and the Caribbean. The outcomes of a recent study done in a Central African country showed that women were 4 times more susceptible to getting AIDS than men, in spite of the fact that there are more men than women in this area of SSA. The reasons that women are so vulnerable are multiple: illiteracy, lack of access to information, prejudices, sexual taboos, and an economic dependency which have all led women towards prostitution and the growing incidence of hetero sexual transmission of AIDS in SSA. Prostitutes are 88% seropositive in Kigali; 16% in Dakar and 90% in Nairobi. 10% of all AIDS cases in SSA are due to transfusions where the blood banks are not monitored because women are loosing large quantities of blood through abortions, hemorrhages, deliveries and chronic anemia due to continuous pregnancies that are badly spaced. Additional problems for women are transmitting AIDS to their babies -- 25-30% of pediatric AIDS are transmitted from mother to child through "vertical transmission (VT)." This VT is a serious problem in East Africa where a survey in Uganda showed that 24% of pregnant women were infected with AIDS. The WHO estimated that between 1980-1987, 80,000 children were infected with AIDS of which 80% died before age 5. AIDS in SSA is taking its toll on women who face environmental, socio-cultural, political and economic discrimination. Such a loss to AIDS to incalculable to society.

  16. MECHANICAL STRENGTH AND RELIABILITY OF SOLID CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Yongdan Li; Dongfang Wu; Y.S. Lin

    2004-01-01

    The mechanical strength of solid catalysts is one of the key parameters for reliable and efficient performance of a fixed bed reactor. Some recent developments and their basic mechanics within this context are reviewed. The main concepts discussed are brittle fracture which leads to the mechanical failure of the catalyst pellets, measurement and statistical properties of the catalyst strength data, and mechanical reliability of the catalyst pellets and their packed bed. The scientific basis for the issues on the catalyst mechanical properties calls yet for further elucidation and advancement.

  17. 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

  18. Formation of Pt-Zn Alloy Nanoparticles by Electron-Beam Irradiation of Wurtzite ZnO in the TEM.

    Science.gov (United States)

    Lee, Sung Bo; Park, Jucheol; van Aken, Peter A

    2016-12-01

    As is well documented, platinum nanoparticles, promising for catalysts for fuel cells, exhibit better catalytic activities, when alloyed with Zn. Pre-existing syntheses of Pt-Zn alloy catalysts are composed of a number of complex steps. In this study, we have demonstrated that nanoparticles of Pt-Zn alloys are simply generated by electron-beam irradiation in a transmission electron microscope of a wurtzite ZnO single-crystal specimen. The initial ZnO specimen is considered to have been contaminated by Pt during specimen preparation by focused ion beam milling. The formation of the nanoparticle is explained within the framework of ionization damage (radiolysis) by electron-beam irradiation and accompanying electrostatic charging. PMID:27440080

  19. Controllable Catalysis with Nanoparticles: Bimetallic Alloy Systems and Surface Adsorbates

    KAUST Repository

    Chen, Tianyou

    2016-05-16

    Transition metal nanoparticles are privileged materials in catalysis due to their high specific surface areas and abundance of active catalytic sites. While many of these catalysts are quite useful, we are only beginning to understand the underlying catalytic mechanisms. Opening the “black box” of nanoparticle catalysis is essential to achieve the ultimate goal of catalysis by design. In this Perspective we highlight recent work addressing the topic of controlled catalysis with bimetallic alloy and “designer” adsorbate-stabilized metal nanoparticles.

  20. Near-surface alloys for hydrogen fuel cell applications

    DEFF Research Database (Denmark)

    Greeley, Jeffrey Philip; Mavrikakis, Manos

    2006-01-01

    Near-surface alloys (NSAs) possess a variety of unusual catalytic properties that could make them useful candidates for improved catalysts in a variety of chemical processes. It is known from previous work, for example, that some NSAs bind hydrogen very weakly while, at the same time, permitting...... facile H-2 activation. These NSAs could, potentially, facilitate highly selective hydrogenation reactions at low temperatures. In the present work, the suitability of NSAs for use as hydrogen fuel cell anodes has been evaluated: the combination of properties, possessed by selected NSAs, of weak binding...

  1. 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

  2. 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.

  3. 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

  4. The carbon-tolerance mechanism of Ni-based alloy with coinage metals

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mingyang; Fu, Zhaoming; Yang, Zongxian, E-mail: yzx@henannu.edu.cn

    2013-11-01

    Using the first-principles calculations, we investigate the successive dehydrogenation of CH{sub 4}, as well as the diffusion of CH (the most important carbon-containing intermediate), on the Ni(111) surfaces doped with coinage metals. It is found that, although alloying of Ni with coinage metals can to some extent affect the CH{sub 4} dehydrogenation, the coking inhibition on the alloy surface mainly roots in the large diffusion barrier of CH, as well as the reduction of the number of active adsorption sites for CH{sub x}. These results give a clue for designing new catalyst with higher coking resistance.

  5. Automotive Catalyst State Diagnosis Using Microwaves

    Directory of Open Access Journals (Sweden)

    Moos Ralf

    2015-01-01

    Full Text Available The state of catalysts plays a key role in automotive exhaust gas aftertreatment. The soot or ash loading of Diesel particulate filters, the oxygen loading degree in three-way catalysts, the amount of stored ammonia in SCR catalysts, or the NOx loading degree in NOx storage catalysts are important parameters that are today determined indirectly and in a model-based manner with gas sensors installed upstream and/or downstream of the catalysts. This contribution gives an overview on a novel approach to determine the catalyst state directly by a microwave-based technique. The method exploits the fact that the catalyst housing acts as a microwave cavity resonator. As “sensing” elements, one or two simple antennas are mounted inside the catalyst canning. The electrical properties of the catalyst device (ceramic honeycomb plus coating and storage material can be measured. Preferably, the resonance characteristics, e.g., the resonance frequencies, of selected cavity modes are observed. The information on the catalyst interior obtained in such a contactless manner is very well correlated with the catalyst state as will be demonstrated for different exhaust gas aftertreatment systems.

  6. 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.

  7. Kinetic Monte Carlo simulation of surface segregation in Pd–Cu alloys

    International Nuclear Information System (INIS)

    The knowledge of surface composition and atomic arrangement is prerequisite for understanding of catalytic properties of an alloy catalyst. Gaining such knowledge is rather difficult, especially for those possessing surface segregation. Pd–Cu alloy is used in many fields and possesses surface segregation. In this paper kinetic Monte Carlo method is used to explore the surface composition and structure and to examine the effects of bulk composition and temperature on the surface segregation of Pd–Cu alloys. It is shown that the segregation basically completes within 900 s at 500 K. Below 900 K and within 20 min the enriched surface Cu atoms mainly come from the top five layers. For the first time we demonstrate that there exists a “bulk-inside flocking” or clustering phenomenon (the same component element congregates in bulk) in Pd–Cu alloys. Our results indicate that for alloys with higher Cu content there are small Pd ensembles like monomers, dimers and trimers with contiguous subsurface Pd atoms. - Highlights: • Kinetic Monte Carlo was first used to study surface segregation of Pd–Cu alloys. • Bulk-inside flocking (the same component element congregates in bulk) was observed. • Small Pd ensembles with contiguous subsurface Pd exist on surfaces of Cu-rich alloys

  8. Kinetic Monte Carlo simulation of surface segregation in Pd–Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feng [Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University (China); He, Xiang [Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Chen, Zhao-Xu, E-mail: zxchen@nju.edu.cn [Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University (China); Huang, Yu-Gai [Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Key Laboratory of Mesoscopic Chemistry of MOE, Nanjing University (China); JiangSu Second Normal University, Nanjing (China)

    2015-11-05

    The knowledge of surface composition and atomic arrangement is prerequisite for understanding of catalytic properties of an alloy catalyst. Gaining such knowledge is rather difficult, especially for those possessing surface segregation. Pd–Cu alloy is used in many fields and possesses surface segregation. In this paper kinetic Monte Carlo method is used to explore the surface composition and structure and to examine the effects of bulk composition and temperature on the surface segregation of Pd–Cu alloys. It is shown that the segregation basically completes within 900 s at 500 K. Below 900 K and within 20 min the enriched surface Cu atoms mainly come from the top five layers. For the first time we demonstrate that there exists a “bulk-inside flocking” or clustering phenomenon (the same component element congregates in bulk) in Pd–Cu alloys. Our results indicate that for alloys with higher Cu content there are small Pd ensembles like monomers, dimers and trimers with contiguous subsurface Pd atoms. - Highlights: • Kinetic Monte Carlo was first used to study surface segregation of Pd–Cu alloys. • Bulk-inside flocking (the same component element congregates in bulk) was observed. • Small Pd ensembles with contiguous subsurface Pd exist on surfaces of Cu-rich alloys.

  9. Sodium citrate assisted facile synthesis of AuPd alloy networks for ethanol electrooxidation with high activity and durability

    Science.gov (United States)

    Zhai, Yanling; Zhu, Zhijun; Lu, Xiaolin; Zhou, H. Susan

    2016-10-01

    The direct ethanol fuel cell is an emerging energy conversion device for which palladium is considered as the one of the most effective components for anode catalyst, however, its widespread application has been still limited by the activity and durability of the anode catalyst. In this work, AuPd alloy networks (NWs) are synthesized using H2PdCl4 and HAuCl4 as precursors reduced by NaBH4 in the presence of sodium citrate (SC). The results reveal that SC plays significant role in network structure, resulting in the enhanced electrocatalytic activity of the catalyst. This self-supported AuPd NWs catalyst exhibits much higher electrochemical catalytic activity than commercial Pd/C catalyst toward ethanol electrooxidation in alkaline solution. Significantly, AuPd NWs catalyst shows extremely high durability at the beginning of the chronoamperometry test, and as high as 49% of the mass current density (1.41 A/mgPd) remains after 4000 s current-time test at -0.3 V (vs. Ag/AgCl) in N2-saturated KOH-ethanol solution. This strategy provides a facile method for the preparation of alloy networks with high electrochemical activity, and can be potentially expanded to a variety of electrochemical applications.

  10. Investigation of nano Pt and Pt-based alloys electrocatalysts for direct methanol fuel cells and their properties

    Directory of Open Access Journals (Sweden)

    Chunguang Suo

    2014-03-01

    Full Text Available The electrocatalysts used in micro direct methanol fuel cell (μDMFC, such as Pt/C and Pt alloy/C, prepared by liquid-phase NaBH4 reduction method have been investigated. XC-72 (Cobalt corp. Company, U.S.A is chosen as the activated carrier for the electrocatalysts to keep the catalysts powder in the range of several nanometers. The XRD, SEM, EDX analyses indicated that the catalysts had small particle size in several nanometers, in excellent dispersed phase and the molar ratio of the precious metals was found to be optimal. The performances of the DMFCs using cathodic catalyst with Pt percentage of 30wt% and different anodic catalysts (Pt-Ru, Pt-Ru-Mo were tested. The polarization curves and power density curves of the cells were measured to determine the optimal alloy composition and condition for the electrocatalysts. The results showed that the micro direct methanol fuel cell with 30wt% Pt/C as the cathodic catalyst and n(Pt:n(Ru:n(Mo = 3:2:2 PtRuMo/C as the anodic catalyst at room temperature using 2.0mol/L methanol solution has the best performances.

  11. Microstructures of erbium modified aluminum-copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berghof-Hasselbaecher, Ellen; Schmidt, Gerald; Galetz, Mathias; Schuetze, Michael [DECHEMA-Forschungsinstitut, Frankfurt am Main (Germany); Masset, Patrick J. [Fraunhofer UMSICHT-ATZ Entwicklungszentrum, Sulzbach-Rosenberg (Germany); Zhang, Ligang [Technische Univ. Bergakademie Freiberg (Germany). ZIK Virtuhcon; Liu, Libin; Jin, Zhanpeng [Central South Univ., Changsha, Hunan (China)

    2012-07-01

    Alloying with rare earth metals improves to the mechanical properties and corrosion resistance of aluminium base alloys at high temperatures. The rare earth metal erbium may be used for grain refinement. Within a project of computer-aided alloy development based on the CALPHAD (CALculation of PHAse Diagrams) method various alloys were melted on the Al-rich side of the ternary system Al-Cu-Er under argon atmosphere and their microstructures were characterized in the as-cast state or after long-term isothermal annealing (400 C/960 h) by means of different investigation techniques. As a result, the phases fcc (Al), {tau}{sub 1}-Al{sub 8}Cu{sub 4}Er, {theta}-CuAl{sub 2}, {eta}-CuAl, and Al{sub 3}Er were identified, their compositions and fractions were quantified, and their hardnesses were determined. The experimental obtained microstructures agree very well with the calculated solidification behaviors of the cast alloys. The knowledge gained from this work about the phase compositions and microstructures can also be utilized for the fine optimization of the phase diagram. (orig.)

  12. Nanotemplated platinum fuel cell catalysts and copper-tin lithium battery anode materials for microenergy devices

    Energy Technology Data Exchange (ETDEWEB)

    Rohan, J.F., E-mail: james.rohan@tyndall.ie [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Hasan, M.; Holubowitch, N. [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland)

    2011-11-01

    Highlights: > Anodic Aluminum oxide formation on Si substrate. > High density nanotemplated Pt catalyst on Si for integrated energy and electronics. > CuSn alloy deposition from a single, high efficiency methanesulfonate plating bath. > Nanotemplated CuSn Li anode electrodes with high capacity retention. - Abstract: Nanotemplated materials have significant potential for applications in energy conversion and storage devices due to their unique physical properties. Nanostructured materials provide additional electrode surface area beneficial for energy conversion or storage applications with short path lengths for electronic and ionic transport and thus the possibility of higher reaction rates. We report on the use of controlled growth of metal and alloy electrodeposited templated nanostructures for energy applications. Anodic aluminium oxide templates fabricated on Si for energy materials integration with electronic devices and their use for fuel cell and battery materials deposition is discussed. Nanostructured Pt anode catalysts for methanol fuel cells are shown. Templated CuSn alloy anodes that possess high capacity retention with cycling for lithium microbattery integration are also presented.

  13. Promoting effect of Ir on the catalytic property of Ru/ZnO catalysts for selective hydrogenation of crotonaldehyde

    International Nuclear Information System (INIS)

    A series of ZnO supported Ru–Ir bimetal catalysts were prepared and tested for vapor-phase selective hydrogenation of crotonaldehyde. The addition of Ir could effectively promote the catalytic performance, especially the catalyst stability. A Ru–0.5Ir/ZnO catalyst showed the highest activity (a conversion of 63.3%) and selectivity to crotyl alcohol (94.4%) after 30 h reaction. The enhanced stability was attributed to the modified electronic property of Ru by the formation of RuIr alloy as the X-ray photoelectron spectroscopy results showed charge transfer from Ru to Ir, as well as the weakened surface acidity in the Ru–Ir/ZnO catalyst as evidenced by NH3 temperature-programmed desorption technique. Besides, the deactivation of the catalysts was due to the strong chemisorption of CO on the metal surface via decarbonylation reaction and deposition of organic compounds on the catalyst surface, which was characterized by CO poisoning experiment, CO temperature-programmed desorption and temperature-programmed oxidation methods.

  14. Titanium alloys. Advances in alloys, processes, products and applications

    OpenAIRE

    Blenkinsop, P.

    1993-01-01

    The last few years have been a period of consolidation of existing alloys and processes. While the aerospace industry remains the principal driving force for alloy development, the paper illustrates examples of new markets being established in "older" alloys, by a combination of product/process development and a re-examination of engineering design parameters. Considerable attention is still being directed towards the titanium aluminide systems, but other more conventional alloy developments ...

  15. 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...

  16. 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.

  17. 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....

  18. 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.

  19. Recent results for bonding S-65C grade Be to copper alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dombrowski, D.W. [Brush Wellman Inc., Cleveland, OH (United States)

    1995-09-01

    Novel processes for bonding beryllium to copper alloys without the use of a silver bonding aid have been developed at Brush Wellman. Tensile strength results will be presented at room temperature and elevated temperatures. A comparison will be made between bond strengths derived from rectangular tensile specimens and reduced section tensile specimens. Failure modes of the specimens at various temperatures will be shown.

  20. Critical assessment of computational thermodynamics in the alloy design of PM high speed steels

    Energy Technology Data Exchange (ETDEWEB)

    Trabadelo, V. [CEIT, Po Manuel Lardizabal 15, 20018 San Sebastian (Spain); Gimenez, S. [K.U. Leuven, Kasteelpark Arenberg 44, B3001 Heverlee (Belgium); Gomez-Acebo, T. [TECNUN, Po Manuel Lardizabal 15, 20018 San Sebastian (Spain); Iturriza, I. [CEIT, Po Manuel Lardizabal 15, 20018 San Sebastian (Spain)]. E-mail: iiturriza@ceit.es

    2005-08-15

    The experimental powder M42HVIG is used to illustrate how the adequate selection of the constituent phases involved in the calculation of multicomponent phase diagrams is a key factor for success in the computer-aided alloy design of highly sinterable high speed steel compositions.

  1. RBF-Type Artificial Neural Network Model Applied in Alloy Design of Steels

    Institute of Scientific and Technical Information of China (English)

    YOU Wei; LIU Ya-xiu; BAI Bing-zhe; FANG Hong-sheng

    2008-01-01

    RBF model, a new type of artificial neural network model was developed to design the content of carbon in low-alloy engineering steels. The errors of the ANN model are. MSE 0. 052 1, MSRE 17. 85%, and VOF 1. 932 9. The results obtained are satisfactory. The method is a powerful aid for designing new steels.

  2. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM

    2013-01-01

    Full Text Available Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium and its alloys [1]. The element and its alloys take a big part of modern industry needs. Especially nowadays magnesium alloys are used in automotive and mechanical (trains and wagons manufacture, because of its lightness and other features. Magnesium and magnesium alloys are the easiest of all metals to machine, allowing machining operations at extremely high speed. All standard machining operations such as turning, drilling, milling, are commonly performed on magnesium parts.

  3. A study of surface tension driven segregation in monotectic alloy systems

    Science.gov (United States)

    Andrews, J. Barry; Andrews, Rosalia N.; Gowens, Terrell F.

    1988-01-01

    The compatibilities of various monotectic alloy systems with several different crucible materials were evaluated. The study was carried out using small candidate alloy samples of compositions that produced fifty volume percent of each liquid phase at the monotectic temperature. Compatibility was based on the evaluation of the wetting tendency of the two immiscible phases with the crucible material in a one-g solidified sample. Three types of wetting phenomena were observed during the evaluation. Type 1 indicates an alloy-crucible combination where the L2 phase preferentially wets the crucible material. Since L2 is usually the minority phase in desirable alloys, this material combination would be difficult to process and is therefore considered incompatible. Type 2 behavior indicates an alloy-crucible combination where the L1 phase preferentially wets the crucible material. This type of combination is considered compatible since surface tension effects should aid in processing the alloy to a useful form. Type 3 indicates any combination that leads to major reactions between the alloy and crucible material, gas entrapment, or separation of the metal from the crucible wall. Additional compatibility evaluations would have to be carried out on combinations of this category. The five alloy systems studied included aluminum-bismuth, copper-lead, aluminum-indium, aluminum-lead and cadmium-gallium. The systems were combined with crucibles of alumina, boron nitride, mullite, quartz, silicon carbide and zirconia.

  4. 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...

  5. 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

  6. 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.

  7. 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.

  8. 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...... in CACE enhancing efficient flow of information between the tools supporting the following phases of the design process. In principle, this flow has to be two-way, and more or less automated, in order to enable the engineer to observe the propagation of the particular design decisions taken at various...... levels.The major conclusions of the paper are related with identifying the factors affecting the software tool integration in a way needed to facilitate design "inter-phase" communication. These are: standard application interfaces, dynamic data exchange mechanisms, code generation techniques and general...

  9. Performative Brand Aid

    DEFF Research Database (Denmark)

    Christiansen, Lene Bull; Olwig, Mette Fog

    This paper argues that contextualizing the celebrity-led benefit event in relation to local cultural norms is of pivotal importance to understanding the rationales behind its execution and its potential impact in terms of local understandings and acts of humanitarianism. The paper is based...... on the analysis of two Danish benefit events: The annual national telethon and media event Danmarks Indsamling (Denmark’s Fundraiser), and the annual small-scale music concert Hammershus Fairtrade Concert. The campaigns are different in scope and location, but share important common global and local features....... By focusing on a peripheral case set outside the classical Anglo-American context we aim to illustrate how the two benefit events seek to promote development aid and fair trade by drawing on a combination of international trends and local sets of cultural norms. The Danish case, we posit, can thereby shed...

  10. 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

  11. 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。

  12. AIDS and sex tourism.

    Science.gov (United States)

    Herold, E S; Van Kerkwijk, C

    1992-01-01

    Tourists traveling internationally lower their inhibitions and take greater risks than they would typically in their home cultures. Loneliness, boredom, and a sense of freedom contribute to this behavioral change. Some tourists travel internationally in search of sexual gratification. This motivation may be actively conscious or subconscious to the traveler. Billed as romantic with great natural beauty, Thailand, the Philippines, Brazil, the Dominican Republic, and Kenya are popular destinations of tourists seeking sex. The Netherlands and countries in eastern Europe are also popular. With most initial cases of HIV infection in Europe having histories of international travel, mass tourism is a major factor in the international transmission of AIDS. While abroad, tourists have sex with casual partners, sex workers, and/or other tourists. Far from all tourists, however, carry and consistently use condoms with these partners. One study found female and non white travelers to be less likely than Whites and males to carry condoms. The risk of HIV infection increases in circumstances where condoms are not readily available in the host country and/or are of poor quality. Regarding actual condom use, a study found only 34% of sex tourists from Switzerland to consistently use condoms while abroad. 28% of men in an STD clinic in Melbourne, Australia, reported consistent condom use in sexual relations while traveling in Asia; STDs were identified in 73% of men examined. The few studies of tourists suggest that a significant proportion engage in risky behavior while traveling. HIV prevalence is rapidly increasing in countries known as destinations for sex tourism. High infection rates are especially evident among teenage sex workers in Thailand. Simply documenting the prevalence of risky behavior among sex tourists will not suffice. More research is needed on travelers and AIDS with particular attention upon the motivating factors supporting persistent high-risk behavior. PMID

  13. [AIDS information in Zimbabwe].

    Science.gov (United States)

    Meyer, L

    1993-11-20

    The difficulties of health education concerning AIDs prevention in Zimbabwe include communicating simple information about complicated processes, resistance to the information because of status or tradition, and lack of experience with translating material that was produced in the West. The beliefs in ghosts and witch doctors are still part of the tradition in Zimbabwe, providing cultural diversity and a sense of identification. Traditional medicine is characterized by Westerners as often irrational behavior that is deleterious to one's health. However, even in the allegedly educated part of the world compliance is often lacking and alternative treatment forms are actively pursued in tandem with formal medicine. When there is a short time period between harmful behavior and infection, most people realize that there is a causative connection. On the other hand, it is a more complicated mental exercise to fathom that intercourse can result in HIV infection that 5 years later may lead to death from tuberculosis. No other disease is known by these people that has a corresponding delay from the time of infection to disease or death. It is also confusing that a sexually transmitted disease does not produce symptoms such as discharge or genital sores. It is difficult to comprehend that a sole causative agent, HIV, can lead to so many different diseases and symptoms. When a young man died after having been hospitalized with protracted cough and TB as a result of HIV infection that he had contracted from a girlfriend, the father told the folks at home that his son had died of TB. These conflicting pieces of information make AIDS prevention education wrought with difficulties, which adds to the rapid spread of the disease, although the authorities and international organizations have responded with strategies, informational materials, and educational courses. PMID:8273086

  14. Structural thermodynamics of alloys

    CERN Document Server

    Manenc, Jack

    1973-01-01

    Technical progress has for a very long time been directly dependent on progress in metallurgy, which is itself connected with improvements in the technology of alloys. Metals are most frequently used in the form of alloys for several reasons: the quantity of pure metal in its native state in the earth's crust is very limited; pure metals must be extracted from ores which are themselves impure. Finally, the methods of treatment used lead more easily to alloys than to pure metals. The most typical case is that of iron, where a pure ore may be found, but which is the starting point for cast iron or steel, alloys of iron and carbon. In addition, the properties of alloys are in general superior to those of pure metals and modem metallurgy consists of controlling these properties so as to make them conform to the requirements of the design office. Whilst the engineer was formerly compelled to adapt his designs and constructions to the materials available, such as wood, stone, bronze, iron, cast iron and ordinary st...

  15. INVESTIGATION OF MAGNESIUM ALLOYS MACHINABILITY

    OpenAIRE

    Berat Barıs BULDUM; Aydın SIK; Iskender OZKUL

    2013-01-01

    Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attra...

  16. Productive Machining of Titanium Alloys

    OpenAIRE

    Čejka, Libor

    2013-01-01

    This diploma thesis is focused on a productive machining of titanium alloys. At the beginning it deals about titanium and its alloys. It describes chip generation mechanism, tool blunting and surface quality. Further it contains modern strategies of efficient titanium alloys machining. Then it analyzes contemporary manufacturing technology of hinge made of titanium alloy Ti-6Al-4V in Frentech Aerospace s.r.o. company, and at the end finds possibility of savings by inovation of roughing process.

  17. Ultrasound-assisted Cinnamaldehyde Hydrogenation to Cinnamyl Alcohol at Atmospheric Pressure over Ru-B Amorphous Catalyst

    Institute of Scientific and Technical Information of China (English)

    LI Hui; MA Chun-Jing; LI He-Xing

    2006-01-01

    The ultrafine Ru-B amorphous alloy catalyst was prepared by chemical reduction with KBH4. During liquid phase hydrogenation of cinnamaldehyde at atmospheric pressure, the Ru-B catalyst prepared exhibited excellent selectivity to cinnamyl alcohol. When the hydrogenation was performed with ultrasonic irradiation, the reaction rate could be greatly enhanced while the selectivity to cinnamyl alcohol remained almost unchanged. The hydrogenation rate was increased with the increase of either the ultrasonic frequency or the irradiation time. According to various characterizations, such as XRD, XPS, TEM, BET and ICP, the effect of ultrasonic irradiation on the structural and electronic characteristics of Ru-B catalyst was studied briefly. Meanwhile, the promotion effect of ultrasonication on the catalytic performance was also discussed based on the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol.

  18. 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...

  19. Surface mechanical behaviour of composite Ni-P-fly ash/zincate coated aluminium alloy

    International Nuclear Information System (INIS)

    Ni-P-fly ash coatings were produced on zincate coated 5083 wrought aluminium alloy substrates with the aid of an electroless deposition technique. Structural and chemical characterization of the produced coatings was performed with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDS) techniques. The Ni-P-fly ash coating was found to consist of an amorphous Ni-P matrix with dispersed fly ash particles. The wear resistance of the Ni-P-fly ash coating on zincate treated aluminium alloy was observed to be higher than that of the bare aluminium alloy, when sliding against a stainless steel counterface. In addition, the adhesion between the Ni-P-fly ash/zincate coating and the aluminium alloy substrate was also studied with a scratch testing apparatus. The adhesion strength of Ni-P-fly ash/zincate coating on the aluminium alloy substrate was observed to be higher in comparison to the Ni-P/zincate coating on the same aluminium alloy.

  20. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter; Koh, Shirlaine; Mani, Prasanna; Ratndeep, Srivastava

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.