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Sample records for single-site catalysts capable

  1. Olefin polymerization from single site catalysts confined within porous media

    Science.gov (United States)

    Kasi, Rajeswari M.

    Single Site Catalysts (SSCs) have been utilized for olefin polymerization. Altering the metal-ligand architecture in the SSCs, polyolefin properties can be enhanced in a rational manner. This influence of the ligands in the SSC on the property of polyolefins prepared can be referred to as the primary ligand influence. Extending this understanding and subsequent control of the metal-ligand framework to the interaction of SSCs within organic and inorganic supports is vital for the synthesis of polyolefins with tailored properties. The motivation behind this thesis was to explore the support influence on the reactivity of the SSC tethered to a support matrix during ethylene homo and copolymerization. In order to address this question of the support influence on the final polyolefin properties, synthetic routes to covalently bind SSCs on different matrices have been explored. Two distinct supported SSCs have been used to prepare branched polyethylenes. Branched polyethylenes can be prepared by either copolymerization (ethylene and alpha-olefin) or oligomerization/copolymerization processes (ethylene and in situ generated alpha-olefin). Synthetic routes to prepare precursor catalysts to Constrained Geometry Catalysts (CGCs) by silyl elimination chemistry have been developed (Chapter 2). Efficient synthetic protocols to assemble CGCs on aminomethylpolysytrene matrices (Chapter 3) and amine-functionalized mesoporous silica (Chapter 4) are also reported. These supported catalysts, with appropriate cocatalysts have been used to prepare ethylene homo and copolymers, the polymer thermal properties and microstructures were analyzed by various analytical techniques. Branched polyethylenes (LLDPE) can be prepared by copolymerization chemistry. It has been observed is that the influence of the support is seen in the production of lower crystalline forms of high density polyethylene (HDPE, 20--50% crystalline), while homogeneous polymerization of analogous soluble CGCs afford HDPE

  2. Understanding the role of aluminum-based activators in single site iron catalysts for ethylene oligomerization.

    OpenAIRE

    Boudene , Zoubeyr; Boudier , Adrien; Breuil , Pierre-Alain; Olivier-Bourbigou , Hélène; Raybaud , Pascal; Toulhoat , Hervé; De Bruin , Theodorus

    2014-01-01

    International audience; In a combined experimental and theoretical study, the activation process of a single site ethylene oligomerization catalyst with aluminum-based activators has been studied. The results put forward a plausible deactivation reaction path of the catalyst for trimethylaluminum, while for methylaluminoxane and a novel phenoxyaluminum-based activator, the experimental catalyst's activity correlates with the energy barrier for the ethylene insertion.

  3. Single-Site Palladium(II) Catalyst for Oxidative Heck Reaction: Catalytic Performance and Kinetic Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Hui; Li, Mengyang; Zhang, Guanghui; Gallagher, James R.; Huang, Zhiliang; Sun, Yu; Luo, Zhong; Chen, Hongzhong; Miller, Jeffrey T.; Zou, Ruqiang; Lei, Aiwen; Zhao, Yanli

    2015-01-01

    ABSTRACT: The development of organometallic single-site catalysts (SSCs) has inspired the designs of new heterogeneous catalysts with high efficiency. Nevertheless, the application of SSCs in certain modern organic reactions, such as C-C bond formation reactions, has still been less investigated. In this study, a single-site Pd(II) catalyst was developed, where 2,2'-bipyridine-grafted periodic mesoporous organosilica (PMO) was employed as the support of a Pd(II) complex. The overall performance of the single-site Pd(II) catalyst in the oxidative Heck reaction was then investigated. The investigation results show that the catalyst displays over 99% selectivity for the product formation with high reaction yield. Kinetic profiles further confirm its high catalytic efficiency, showing that the rate constant is nearly 40 times higher than that for the free Pd(II) salt. X-ray absorption spectroscopy reveals that the catalyst has remarkable lifetime and recyclability.

  4. Catalytic water oxidation by single-site ruthenium catalysts.

    Science.gov (United States)

    Concepcion, Javier J; Jurss, Jonah W; Norris, Michael R; Chen, Zuofeng; Templeton, Joseph L; Meyer, Thomas J

    2010-02-15

    A series of monomeric ruthenium polypyridyl complexes have been synthesized and characterized, and their performance as water oxidation catalysts has been evaluated. The diversity of ligand environments and how they influence rates and reaction thermodynamics create a platform for catalyst design with controllable reactivity based on ligand variations.

  5. Single-site catalyst promoters accelerate metal-catalyzed nitroarene hydrogenation

    KAUST Repository

    Wang, Liang

    2018-04-04

    Atomically dispersed supported metal catalysts are drawing wide attention because of the opportunities they offer for new catalytic properties combined with efficient use of the metals. We extend this class of materials to catalysts that incorporate atomically dispersed metal atoms as promoters. The catalysts are used for the challenging nitroarene hydrogenation and found to have both high activity and selectivity. The promoters are single-site Sn on TiO2 supports that incorporate metal nanoparticle catalysts. Represented as M/Sn-TiO2 (M = Au, Ru, Pt, Ni), these catalysts decidedly outperform the unpromoted supported metals, even for hydrogenation of nitroarenes substituted with various reducible groups. The high activity and selectivity of these catalysts result from the creation of oxygen vacancies on the TiO2 surface by single-site Sn, which leads to efficient, selective activation of the nitro group coupled with a reaction involving hydrogen atoms activated on metal nanoparticles.

  6. Metal–organic and covalent organic frameworks as single-site catalysts

    Science.gov (United States)

    Rogge, S. M. J.; Bavykina, A.; Hajek, J.; Garcia, H.; Olivos-Suarez, A. I.; Sepúlveda-Escribano, A.; Vimont, A.; Clet, G.; Bazin, P.; Kapteijn, F.

    2017-01-01

    Heterogeneous single-site catalysts consist of isolated, well-defined, active sites that are spatially separated in a given solid and, ideally, structurally identical. In this review, the potential of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) as platforms for the development of heterogeneous single-site catalysts is reviewed thoroughly. In the first part of this article, synthetic strategies and progress in the implementation of such sites in these two classes of materials are discussed. Because these solids are excellent playgrounds to allow a better understanding of catalytic functions, we highlight the most important recent advances in the modelling and spectroscopic characterization of single-site catalysts based on these materials. Finally, we discuss the potential of MOFs as materials in which several single-site catalytic functions can be combined within one framework along with their potential as powerful enzyme-mimicking materials. The review is wrapped up with our personal vision on future research directions. PMID:28338128

  7. A stable rhodium single-site catalyst encapsulated within dendritic mesoporous nanochannels.

    Science.gov (United States)

    Tian, Jun; Yang, Dali; Wen, Jianguo; Filatov, Alexander S; Liu, Yuzi; Lei, Aiwen; Lin, Xiao-Min

    2018-01-18

    Catalysis plays an essential role in the modern chemical industry. However, it still remains a great challenge to improve the efficiency of many heterogeneous catalysts based on a per metal atom basis. Single-site catalysts (SsCs) with isolated metal atoms/ions anchored to the supports are thus highly desirable, providing an innovative solution towards highly efficient usage of precious metal atoms in heterogeneous catalysts. Creating SsCs with high metal loading proves to be challenging because, without robust anchoring, atoms tend to diffuse to form large aggregates during catalytic reactions. We report a facile ligand exchange method to anchor a single-site Rh catalyst inside the individual channels of three-dimensional dendritic mesoporous silica nanospheres (MSNSs). The short porous channels inside MSNSs provide an easy access of reactants and the strong binding of the ligand prevents the aggregation of catalyst sites. The as-synthesized Rh 1 @MSNS-NH 2 catalyst shows excellent activity, stability and reusability in the reduction of 4-nitrophenol. The same catalyst shows high regioselectivity in the hydrosilylation of terminal alkynes to yield α-vinylsilanes through the Markovnikov addition.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-30

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

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

    Science.gov (United States)

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

    2016-08-30

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

  10. Sintering-resistant Single-Site Nickel Catalyst Supported by Metal-Organic Framework

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhanyong; Schweitzer, Neil; League, Aaron; Bernales Candia, Sandra Varinia; Peters, Aaron; Getsoian, Andrew G.; Wang, Timothy; Miller, Jeffrey T.; Vjunov, Aleksei; Fulton, John L.; Lercher, Johannes A.; Cramer, Christopher J.; Gagliardi, Laura; Hupp, Joseph; Farha, Omar

    2016-02-17

    Developing supported single-site catalysts is an important goal in heterogeneous catalysis, since the well-defined active sites afford opportunities for detailed mechanistic studies, thereby facilitating the design of improved catalysts. We present herein a method for installing Ni ions uniformly and precisely on the node of a Zr-based MOF, NU-1000, in high density and large quantity (denoted as Ni-AIM) using atomic layer deposition (ALD) in a metal–organic framework (MOF) (AIM). Ni-AIM is demonstrated to be an efficient gas-phase hydrogenation catalyst upon activation. The structure of the active sites in Ni-AIM is proposed, revealing its single-site nature. More importantly, due to the organic linker used to construct the MOF support, the Ni ions stay isolated throughout the hydrogenation catalysis, in accord with its long-term stability. A quantum chemical characterization of the catalyst and the catalytic process complements the experimental results. With validation of computational modeling protocols, we further targeted ethylene oligomerization catalysis by Ni-AIM guided by theoretical prediction. Given the generality of the AIM methodology, this emerging class of materials should prove ripe for the discovery of new catalysts for the transformation of volatile substrates.

  11. Sintering-Resistant Single-Site Nickel Catalyst Supported by Metal-Organic Framework.

    Science.gov (United States)

    Li, Zhanyong; Schweitzer, Neil M; League, Aaron B; Bernales, Varinia; Peters, Aaron W; Getsoian, Andrew Bean; Wang, Timothy C; Miller, Jeffrey T; Vjunov, Aleksei; Fulton, John L; Lercher, Johannes A; Cramer, Christopher J; Gagliardi, Laura; Hupp, Joseph T; Farha, Omar K

    2016-02-17

    Developing supported single-site catalysts is an important goal in heterogeneous catalysis since the well-defined active sites afford opportunities for detailed mechanistic studies, thereby facilitating the design of improved catalysts. We present herein a method for installing Ni ions uniformly and precisely on the node of a Zr-based metal-organic framework (MOF), NU-1000, in high density and large quantity (denoted as Ni-AIM) using atomic layer deposition (ALD) in a MOF (AIM). Ni-AIM is demonstrated to be an efficient gas-phase hydrogenation catalyst upon activation. The structure of the active sites in Ni-AIM is proposed, revealing its single-site nature. More importantly, due to the organic linker used to construct the MOF support, the Ni ions stay isolated throughout the hydrogenation catalysis, in accord with its long-term stability. A quantum chemical characterization of the catalyst and the catalytic process complements the experimental results. With validation of computational modeling protocols, we further targeted ethylene oligomerization catalysis by Ni-AIM guided by theoretical prediction. Given the generality of the AIM methodology, this emerging class of materials should prove ripe for the discovery of new catalysts for the transformation of volatile substrates.

  12. Bis(benzimidazole)amine vanadium catalysts for olefin polymerisation and co-polymerisation: thermally robust, single-site catalysts activated by simple alkylaluminium reagents.

    Science.gov (United States)

    Tomov, Atanas K; Gibson, Vernon C; Zaher, Damien; Elsegood, Mark R J; Dale, Sophie H

    2004-09-07

    Vanadium complexes containing bis(benzimidazole)amine ligands, upon activation by simple alkylaluminium reagents, give unusually robust, single-site, catalysts for olefin polymerisation/co-polymerisation.

  13. Single-Site Heterogeneous Catalysts: Innovations, Advantages, and Future Potential in Green Chemistry and Sustainable Technology

    Science.gov (United States)

    Raja, Robert; Thomas, John Meurig

    The advantages that flow from the availability of single-site heterogeneous catalysts are many. They facilitate the determination of the kinetics and mechanism of catalytic turnover and render accessible the energetics of various intermediates. More importantly, it is possible to prepare soluble molecular fragments that circumscribe the single site, thus enabling a direct comparison to be made between the catalytic performance of the same active site when functioning as a heterogeneous or a homogeneous catalyst. Our approach adopts the principles and practices of solid-state chemistry, augmented by lessons derived from enzymology, as well as computational chemistry. We have succeeded in designing a range of new catalysts to effect, inter alia, shape-selective, regioselective, bifunctional, and enantioselective catalytic conversions. In particular, large fractions of these catalysts are ideally suited for the era of clean technology in which single-step and/or solvent-free processes abound, and in which benign oxidants such as air or oxygen and inexpensive nanoporous materials are employed.

  14. Reactivity of a Carbon-Supported Single-Site Molybdenum Dioxo Catalyst for Biodiesel Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mouat, Aidan R.; Lohr, Tracy L.; Wegener, Evan C.; Miller, Jeffrey T.; Delferro, Massimiliano; Stair, Peter C.; Marks, Tobin J.

    2016-08-23

    A single-site molybdenum dioxo catalyst, (Oc)2Mo(=O)2@C, was prepared via direct grafting of MoO2Cl2(dme) (dme = 1,2-dimethoxyethane) on high-surface- area activated carbon. The physicochemical and chemical properties of this catalyst were fully characterized by N2 physisorption, ICP-AES/OES, PXRD, STEM, XPS, XAS, temperature-programmed reduction with H2 (TPR-H2), and temperature-programmed NH3 desorption (TPD-NH3). The single-site nature of the Mo species is corroborated by XPS and TPR-H2 data, and it exhibits the lowest reported MoOx Tmax of reduction reported to date, suggesting a highly reactive MoVI center. (Oc)2Mo(=O)2@C catalyzes the transesterification of a variety of esters and triglycerides with ethanol, exhibiting high activity at moderate temperatures (60-90 °C) and with negligible deactivation. (Oc)2Mo(=O)2@C is resistant to water and can be recycled at least three times with no loss of activity. The transesterification reaction is determined experimentally to be first order in [ethanol] and first order in [Mo] with ΔH = 10.5(8) kcal mol-1 and ΔS = -32(2) eu. The low energy of activation is consistent with the moderate conditions needed to achieve rapid turnover. This highly active carbon-supported single-site molybdenum dioxo species is thus an efficient, robust, and lowcost catalyst with significant potential for transesterification processes.

  15. Catalysis by Design: Well-Defined Single-Site Heterogeneous Catalysts

    KAUST Repository

    Pelletier, Jeremie

    2016-03-09

    ConspectusHeterogeneous catalysis, a field important industrially and scientifically, is increasingly seeking and refining strategies to render itself more predictable. The main issue is due to the nature and the population of catalytically active sites. Their number is generally low to very low, their "acid strengths" or " redox properties" are not homogeneous, and the material may display related yet inactive sites on the same material. In many heterogeneous catalysts, the discovery of a structure-activity reationship is at best challenging. One possible solution is to generate single-site catalysts in which most, if not all, of the sites are structurally identical. Within this context and using the right tools, the catalyst structure can be designed and well-defined, to reach a molecular understanding. It is then feasible to understand the structure-activity relationship and to develop predictable heterogeneous catalysis. Single-site well-defined heterogeneous catalysts can be prepared using concepts and tools of surface organometallic chemistry (SOMC). This approach operates by reacting organometallic compounds with surfaces of highly divided oxides (or of metal nanoparticles). This strategy has a solid track record to reveal structure-activity relationship to the extent that it is becoming now quite predictable. Almost all elements of the periodical table have been grafted on surfaces of oxides (from simple oxides such as silica or alumina to more sophisticated materials regarding composition or porosity).Considering catalytic hydrocarbon transformations, heterogeneous catalysis outcome may now be predicted based on existing mechanistic proposals and the rules of molecular chemistry (organometallic, organic) associated with some concepts of surface sciences. A thorough characterization of the grafted metal centers must be carried out using tools spanning from molecular organometallic or surface chemistry. By selection of the metal, its ligand set, and the

  16. Catalysis by Design: Well-Defined Single-Site Heterogeneous Catalysts.

    Science.gov (United States)

    Pelletier, Jérémie D A; Basset, Jean-Marie

    2016-04-19

    Heterogeneous catalysis, a field important industrially and scientifically, is increasingly seeking and refining strategies to render itself more predictable. The main issue is due to the nature and the population of catalytically active sites. Their number is generally low to very low, their "acid strengths" or " redox properties" are not homogeneous, and the material may display related yet inactive sites on the same material. In many heterogeneous catalysts, the discovery of a structure-activity reationship is at best challenging. One possible solution is to generate single-site catalysts in which most, if not all, of the sites are structurally identical. Within this context and using the right tools, the catalyst structure can be designed and well-defined, to reach a molecular understanding. It is then feasible to understand the structure-activity relationship and to develop predictable heterogeneous catalysis. Single-site well-defined heterogeneous catalysts can be prepared using concepts and tools of surface organometallic chemistry (SOMC). This approach operates by reacting organometallic compounds with surfaces of highly divided oxides (or of metal nanoparticles). This strategy has a solid track record to reveal structure-activity relationship to the extent that it is becoming now quite predictable. Almost all elements of the periodical table have been grafted on surfaces of oxides (from simple oxides such as silica or alumina to more sophisticated materials regarding composition or porosity). Considering catalytic hydrocarbon transformations, heterogeneous catalysis outcome may now be predicted based on existing mechanistic proposals and the rules of molecular chemistry (organometallic, organic) associated with some concepts of surface sciences. A thorough characterization of the grafted metal centers must be carried out using tools spanning from molecular organometallic or surface chemistry. By selection of the metal, its ligand set, and the support taken

  17. Single-Site Active Iron-Based Bifunctional Oxygen Catalyst for a Compressible and Rechargeable Zinc-Air Battery.

    Science.gov (United States)

    Ma, Longtao; Chen, Shengmei; Pei, Zengxia; Huang, Yan; Liang, Guojin; Mo, Funian; Yang, Qi; Su, Jun; Gao, Yihua; Zapien, Juan Antonio; Zhi, Chunyi

    2018-02-27

    The exploitation of a high-efficient, low-cost, and stable non-noble-metal-based catalyst with oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) simultaneously, as air electrode material for a rechargeable zinc-air battery is significantly crucial. Meanwhile, the compressible flexibility of a battery is the prerequisite of wearable or/and portable electronics. Herein, we present a strategy via single-site dispersion of an Fe-N x species on a two-dimensional (2D) highly graphitic porous nitrogen-doped carbon layer to implement superior catalytic activity toward ORR/OER (with a half-wave potential of 0.86 V for ORR and an overpotential of 390 mV at 10 mA·cm -2 for OER) in an alkaline medium. Furthermore, an elastic polyacrylamide hydrogel based electrolyte with the capability to retain great elasticity even under a highly corrosive alkaline environment is utilized to develop a solid-state compressible and rechargeable zinc-air battery. The creatively developed battery has a low charge-discharge voltage gap (0.78 V at 5 mA·cm -2 ) and large power density (118 mW·cm -2 ). It could be compressed up to 54% strain and bent up to 90° without charge/discharge performance and output power degradation. Our results reveal that single-site dispersion of catalytic active sites on a porous support for a bifunctional oxygen catalyst as cathode integrating a specially designed elastic electrolyte is a feasible strategy for fabricating efficient compressible and rechargeable zinc-air batteries, which could enlighten the design and development of other functional electronic devices.

  18. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    International Nuclear Information System (INIS)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    Graphical abstract: Ligand-modified signal-site SBA-15 supported zirconium catalysts were synthesized by SOMC method and characterized by a variety of techniques. The zirconium surface complexes show high catalytic efficiency for cyanosilylation of benzaldehyde. - Highlights: • Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique. • The structures of the Zr species have been characterized by a variety of techniques. • The anchored Zr species are single-sited surface complexes. • The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde. - Abstract: A successive anchoring of Zr(NMe 2 ) 4 , cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15 -500 ) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15 -500 supported zirconium complexes were characterized by in situ FT-IR, 13 C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands

  19. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang, E-mail: gfzhang@snnu.edu.cn; Gao, Ziwei, E-mail: zwgao@snnu.edu.cn

    2015-01-15

    Graphical abstract: Ligand-modified signal-site SBA-15 supported zirconium catalysts were synthesized by SOMC method and characterized by a variety of techniques. The zirconium surface complexes show high catalytic efficiency for cyanosilylation of benzaldehyde. - Highlights: • Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique. • The structures of the Zr species have been characterized by a variety of techniques. • The anchored Zr species are single-sited surface complexes. • The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde. - Abstract: A successive anchoring of Zr(NMe{sub 2}){sub 4}, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15{sub -500}) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15{sub -500} supported zirconium complexes were characterized by in situ FT-IR, {sup 13}C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands.

  20. Highly efficient one-step conversion of cyclohexane to adipic acid using single-site heterogeneous catalysts.

    Science.gov (United States)

    Raja, Robert; Thomas, John Meurig; Xu, Mingcan; Harris, Kenneth D M; Greenhill-Hooper, Michael; Quill, Kieran

    2006-01-28

    A solid source of 'active' oxygen (acetylperoxyborate, APB), when dissolved in aqueous solution in the presence of a single-site microporous catalyst containing redox centres (Fe(III)AlPO-31, Mn(III)AlPO-5, Fe(III)AlPO-5), converts cyclohexane with high efficiency (ca. 88%) and exceptionally high selectivity (ca. 81%) to adipic acid at 383 K; this procedure is also effective in converting styrene to styrene oxide and -pinene and (+)-limonene to their corresponding epoxides.

  1. A Single-Site Iron(III-Salan Catalyst for Converting COS to Sulfur-Containing Polymers

    Directory of Open Access Journals (Sweden)

    Ge-Ge Gu

    2017-10-01

    Full Text Available An iron(III complex of tetradentate N,N′-disubstituted bis(aminophenoxide (designated as salan, a saturated version of the corresponding salen ligand with a sterically hindered organic base anchored on the ligand framework, can selectively mediate the conversion of carbonyl sulfide to sulfur-containing polymers by the copolymerization with epoxides. This single-site catalyst exhibits broad substrate scope, and the resultant copolymers have completely alternating structures. In addition, this catalyst is efficient in producing diblock copolymers, suggesting a living polymerization nature.

  2. Homogeneity of Surface Sites in Supported Single-Site Metal Catalysts: Assessment with Band Widths of Metal Carbonyl Infrared Spectra.

    Science.gov (United States)

    Hoffman, Adam S; Fang, Chia-Yu; Gates, Bruce C

    2016-10-06

    Determining and controlling the uniformity of isolated metal sites on surfaces of supports are central goals in investigations of single-site catalysts because well-defined species provide opportunities for fundamental understanding of the surface sites. CO is a useful probe of surface metal sites, often reacting with them to form metal carbonyls, the infrared spectra of which provide insights into the nature of the sites and the metal-support interface. Metals bonded to various support surface sites give broad bands in the spectra, and when narrow bands are observed, they indicate a high degree of uniformity of the metal sites. Much recent work on single-site catalysts has been done with supports that are inherently nonuniform, giving supported metal species that are therefore nonuniform. Herein we summarize values of ν CO data characterizing supported iridium gem-dicarbonyls, showing that the most nearly uniform of them are those supported on zeolites and the least uniform are those supported on metal oxides. Guided by ν CO data of supported iridium gem-dicarbonyls, we have determined new, general synthesis methods to maximize the degree of uniformity of iridium species on zeolites and on MgO. We report results for a zeolite HY-supported iridium gem-dicarbonyl with full width at half-maximum values of only 4.6 and 5.2 cm -1 characterizing the symmetric and asymmetric CO stretches and implying that this is the most nearly uniform supported single-site metal catalyst.

  3. Design and Use of Nanostructured Single-Site Heterogeneous Catalysts for the Selective Transformation of Fine Chemicals

    Directory of Open Access Journals (Sweden)

    Vladimiro Dal Santo

    2010-05-01

    Full Text Available Nanostructured single-site heterogeneous catalysts possess the advantages of classical solid catalysts, in terms of easy recovery and recycling, together with a defined tailored chemical and steric environment around the catalytically active metal site. The use of inorganic oxide supports with selected shape and porosity at a nanometric level may have a relevant impact on the regio- and stereochemistry of the catalytic reaction. Analogously, by choosing the optimal preparation techniques to obtain spatially isolated and well-characterised active sites, it is possible to achieve performances that are comparable to (or, in the most favourable cases, better than those obtained with homogeneous systems. Such catalysts are therefore particularly suitable for the transformation of highly-functionalised fine chemicals and some relevant examples where high chemo-, regio- and stereoselectivity are crucial will be described.

  4. Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

    International Nuclear Information System (INIS)

    Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    A successive anchoring of Ti(NMe 2 ) 4 , cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, 13 C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands. - Graphical abstract: The ligand-tailored silica supported “single site” titanium complexes were synthesized by SOMC strategy and fully characterized. Their catalytic activity were evaluated by benzaldehyde silylcyanation. - Highlights: • Single-site silica supported Ti active species was prepared by SOMC technique. • O-donor ligand tailored Ti surface species was synthesized. • The surface species was characterized by XPS, 13 C CP-MAS NMR, XANES etc. • Catalytic activity of the Ti active species in silylcyanation reaction was evaluated

  5. Highly Stereoselective Heterogeneous Diene Polymerization by Co-MFU-4l: A Single-Site Catalyst Prepared by Cation Exchange.

    Science.gov (United States)

    Dubey, Romain J-C; Comito, Robert J; Wu, Zhenwei; Zhang, Guanghui; Rieth, Adam J; Hendon, Christopher H; Miller, Jeffrey T; Dincă, Mircea

    2017-09-13

    Molecular catalysts offer tremendous advantages for stereoselective polymerization because their activity and selectivity can be optimized and understood mechanistically using the familiar tools of organometallic chemistry. Yet, this exquisite control over selectivity comes at an operational price that is generally not justifiable for the large-scale manufacture of polyfolefins. In this report, we identify Co-MFU-4l, prepared by cation exchange in a metal-organic framework, as a solid catalyst for the polymerization of 1,3-butadiene with high stereoselectivity (>99% 1,4-cis). To our knowledge, this is the highest stereoselectivity achieved with a heterogeneous catalyst for this transformation. The polymer's low polydispersity (PDI ≈ 2) and the catalyst's ready recovery and low leaching indicate that our material is a structurally resilient single-site heterogeneous catalyst. Further characterization of Co-MFU-4l by X-ray absorption spectroscopy provided evidence for discrete, tris-pyrazolylborate-like coordination of Co(II). With this information, we identify a soluble cobalt complex that mimics the structure and reactivity of Co-MFU-4l, thus providing a well-defined platform for studying the catalytic mechanism in the solution phase. This work underscores the capacity for small molecule-like tunability and mechanistic tractability available to transition metal catalysis in metal-organic frameworks.

  6. Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang, E-mail: gfzhang@snnu.edu.cn; Gao, Ziwei, E-mail: zwgao@snnu.edu.cn

    2015-01-15

    A successive anchoring of Ti(NMe{sub 2}){sub 4}, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1′-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, {sup 13}C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands. - Graphical abstract: The ligand-tailored silica supported “single site” titanium complexes were synthesized by SOMC strategy and fully characterized. Their catalytic activity were evaluated by benzaldehyde silylcyanation. - Highlights: • Single-site silica supported Ti active species was prepared by SOMC technique. • O-donor ligand tailored Ti surface species was synthesized. • The surface species was characterized by XPS, {sup 13}C CP-MAS NMR, XANES etc. • Catalytic activity of the Ti active species in silylcyanation reaction was evaluated.

  7. Ligand-tailored single-site silica supported titanium catalysts: Synthesis, characterization and towards cyanosilylation reaction

    Science.gov (United States)

    Xu, Wei; Li, Yani; Yu, Bo; Yang, Jindou; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    A successive anchoring of Ti(NMe2)4, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1‧-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on silica was conducted by SOMC strategy in moderate conditions. The silica, monitored by in-situ Fourier transform infrared spectroscopy (in-situ FT-IR), was pretreated at different temperatures (200, 500 and 800 °C). The ligand tailored silica-supported titanium complexes were characterized by in-situ FT-IR, 13C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) and elemental analysis in detail, verifying that the surface titanium species are single sited. The catalytic activity of the ligand tailored single-site silica supported titanium complexes was evaluated by a cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the dehydroxylation temperatures of silica and the configuration of the ligands.

  8. Isospecific propylene polymerization with in situ generated bis(phenoxy-amine)zirconium and hafnium single site catalysts.

    Science.gov (United States)

    Makio, Haruyuki; Prasad, Aitha Vishwa; Terao, Hiroshi; Saito, Junji; Fujita, Terunori

    2013-07-07

    Bis(phenoxy-imine) Zr and Hf complexes were activated with (i)Bu3Al or (i)Bu2AlH in conjunction with Ph3CB(C6F5)4 and tested as catalysts for propylene polymerization with emphasis on the enantioselectivity of the isospecific species and the single site polymerization characteristics. The isoselective species was identified as the in situ generated bis(phenoxy-amine) complex whose isoselectivity was sensitive to subtle changes in ligand structure. By employing specific substituents at certain key positions the isotacticity reached an extremely high level comparable to high-end commercial isotactic polypropylenes (Tm > 160 °C). Single site polymerization characteristics depended upon the efficiency and selectivity of the in situ imine reduction which is sensitive to the substituent on the imine nitrogen and the reaction conditions. By using (i)Bu2AlH as a reducing agent, quantitative imine reduction can be achieved with a stoichiometric amount of the reducing agent. This lower alkylaluminum loading is beneficial for the catalyst and significantly enhances the polymerization activity and the molecular weight of the resultant polymer.

  9. Lability and Basicity of Bipyridine-Carboxylate-Phosphonate Ligand Accelerate Single-Site Water Oxidation by Ruthenium-Based Molecular Catalysts.

    Science.gov (United States)

    Shaffer, David W; Xie, Yan; Szalda, David J; Concepcion, Javier J

    2017-11-01

    A critical step in creating an artificial photosynthesis system for energy storage is designing catalysts that can thrive in an assembled device. Single-site catalysts have an advantage over bimolecular catalysts because they remain effective when immobilized. Hybrid water oxidation catalysts described here, combining the features of single-site bis-phosphonate catalysts and fast bimolecular bis-carboxylate catalysts, have reached turnover frequencies over 100 s -1 , faster than both related catalysts under identical conditions. The new [(bpHc)Ru(L) 2 ] (bpH 2 cH = 2,2'-bipyridine-6-phosphonic acid-6'-carboxylic acid, L = 4-picoline or isoquinoline) catalysts proceed through a single-site water nucleophilic attack pathway. The pendant phosphonate base mediates O-O bond formation via intramolecular atom-proton transfer with a calculated barrier of only 9.1 kcal/mol. Additionally, the labile carboxylate group allows water to bind early in the catalytic cycle, allowing intramolecular proton-coupled electron transfer to lower the potentials for oxidation steps and catalysis. That a single-site catalyst can be this fast lends credence to the possibility that the oxygen evolving complex adopts a similar mechanism.

  10. Lability and Basicity of Bipyridine-Carboxylate-Phosphonate Ligand Accelerate Single-Site Water Oxidation by Ruthenium-Based Molecular Catalysts

    International Nuclear Information System (INIS)

    Shaffer, David W.; Xie, Yan; Szalda, David J.; Concepcion, Javier J.

    2017-01-01

    Here, a critical step in creating an artificial photosynthesis system for energy storage is designing catalysts that can thrive in an assembled device. Single-site catalysts have an advantage over bimolecular catalysts because they remain effective when immobilized. Hybrid water oxidation catalysts described here, combining the features of single-site bis-phosphonate catalysts and fast bimolecular bis-carboxylate catalysts, have reached turnover frequencies over 100 s –1 , faster than both related catalysts under identical conditions. The new [(bpHc)Ru(L) 2 ] (bpH 2 cH = 2,2'-bipyridine-6-phosphonic acid-6'-carboxylic acid, L = 4-picoline or isoquinoline) catalysts proceed through a single-site water nucleophilic attack pathway. The pendant phosphonate base mediates O–O bond formation via intramolecular atom-proton transfer with a calculated barrier of only 9.1 kcal/mol. Additionally, the labile carboxylate group allows water to bind early in the catalytic cycle, allowing intramolecular proton-coupled electron transfer to lower the potentials for oxidation steps and catalysis. That a single-site catalyst can be this fast lends credence to the possibility that the oxygen evolving complex adopts a similar mechanism.

  11. Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

    Science.gov (United States)

    Xu, Wei; Yu, Bo; Zhang, Ying; Chen, Xi; Zhang, Guofang; Gao, Ziwei

    2015-01-01

    A successive anchoring of Zr(NMe2)4, cyclopentadiene and a O-donor ligand, 1-hydroxyethylbenzene (PEA), 1,1‧-bi-2-naphthol (Binol) or 2,3-dihydroxybutanedioic acid diethyl ester (Tartrate), on dehydroxylated SBA-15 pretreated at 500 °C for 16 h (SBA-15-500) was conducted by SOMC strategy in moderate conditions. The dehydoxylation of SBA-15 was monitored by in situ Fourier transform infrared spectroscopy (in situ FT-IR). The ligand-modified SBA-15-500 supported zirconium complexes were characterized by in situ FT-IR, 13C CP MAS-NMR, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MAS) and elemental analysis in detail, verifying that the surface zirconium species are single-sited. The catalytic activity of these complexes was evaluated by cyanosilylation of benzaldehyde. The results showed that the catalytic activity is dependent strongly on the structure of surface species and the configuration of the ligands.

  12. Stabilizing Single Sites on Solid Supports: Robust Grafted Ti(IV)-Calixarene Olefin Epoxidation Catalysts via Surface Polymerization and Cross-Linking

    OpenAIRE

    Guo, Yijun; Solovyov, Andrew; Grosso-Giordano, Nicolás A.; Hwang, Son-Jong; Katz, Alexander

    2016-01-01

    This manuscript develops a surface polymerization and cross-linking approach for the stabilization of single-site catalysts on solid surfaces, which is demonstrated here for grafted Ti(IV)-calixarene Lewis acids on silica. Our approach relies on cationic polymerization that is initiated by an adsorbed B(C_6F_5)_3 and uses styrene as the monomer and diisopropenylbenzene as the cross-linking agent. The mildness of this polymerization method is demonstrated by its lack of blocking micropores and...

  13. Surface structural-chemical characterization of a single-site d0 heterogeneous arene hydrogenation catalyst having 100% active sites

    Science.gov (United States)

    Williams, Linda A.; Guo, Neng; Motta, Alessandro; Delferro, Massimiliano; Fragalà, Ignazio L.; Miller, Jeffrey T.; Marks, Tobin J.

    2013-01-01

    Structural characterization of the catalytically significant sites on solid catalyst surfaces is frequently tenuous because their fraction, among all sites, typically is quite low. Here we report the combined application of solid-state 13C-cross-polarization magic angle spinning nuclear magnetic resonance (13C-CPMAS-NMR) spectroscopy, density functional theory (DFT), and Zr X-ray absorption spectroscopy (XAS) to characterize the adsorption products and surface chemistry of the precatalysts (η5-C5H5)2ZrR2 (R = H, CH3) and [η5-C5(CH3)5]Zr(CH3)3 adsorbed on Brønsted superacidic sulfated alumina (AlS). The latter complex is exceptionally active for benzene hydrogenation, with ∼100% of the Zr sites catalytically significant as determined by kinetic poisoning experiments. The 13C-CPMAS-NMR, DFT, and XAS data indicate formation of organozirconium cations having a largely electrostatic [η5-C5(CH3)5]Zr(CH3)2+···AlS− interaction with greatly elongated Zr···OAlS distances of ∼2.35(2) Å. The catalytic benzene hydrogenation cycle is stepwise understandable by DFT, and proceeds via turnover-limiting H2 delivery to surface [η5-C5(CH3)5]ZrH2(benzene)+···AlS− species, observable by solid-state NMR and XAS. PMID:23269836

  14. Tuning the properties of metal–organic framework nodes as supports of single-site iridium catalysts: node modification by atomic layer deposition of aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dong [Department of Chemical Engineering; University of California; Davis; USA; Momeni, Mohammad R. [Department of Chemistry; Chemical Theory Center; Supercomputing Institute; University of Minnesota; Minneapolis; Demir, Hakan [Department of Chemistry; Chemical Theory Center; Supercomputing Institute; University of Minnesota; Minneapolis; Pahls, Dale R. [Department of Chemistry; Chemical Theory Center; Supercomputing Institute; University of Minnesota; Minneapolis; Rimoldi, Martino [Department of Chemistry; Northwestern University; Evanston; USA; Wang, Timothy C. [Department of Chemistry; Northwestern University; Evanston; USA; Farha, Omar K. [Department of Chemistry; Northwestern University; Evanston; USA; Department of Chemistry; Hupp, Joseph T. [Department of Chemistry; Northwestern University; Evanston; USA; Cramer, Christopher J. [Department of Chemistry; Chemical Theory Center; Supercomputing Institute; University of Minnesota; Minneapolis; Gates, Bruce C. [Department of Chemical Engineering; University of California; Davis; USA; Gagliardi, Laura [Department of Chemistry; Chemical Theory Center; Supercomputing Institute; University of Minnesota; Minneapolis

    2017-01-01

    The metal–organic framework NU-1000, with Zr6-oxo, hydroxo, and aqua nodes, was modified by incorporation of hydroxylated Al(iii) ions by ALD-like chemistry with [Al(CH3)2(iso-propoxide)]2followed by steam (ALD = atomic layer deposition). Al ions were installed to the extent of approximately 7 per node. Single-site iridium diethylene complexes were anchored to the nodes of the modified and unmodified MOFs by reaction with Ir(C2H4)2(acac) (acac = acetylacetonate) and converted to Ir(CO)2complexes by treatment with CO. Infrared spectra of these supported complexes show that incorporation of Al weakened the electron donor tendency of the MOF. Correspondingly, the catalytic activity of the initial supported iridium complexes for ethylene hydrogenation increased, as did the selectivity for ethylene dimerization. The results of density functional theory calculations with a simplified model of the nodes incorporating Al(iii) ions are in qualitative agreement with some catalyst performance data.

  15. "Hydro-metathesis" of olefins: A catalytic reaction using a bifunctional single-site tantalum hydride catalyst supported on fibrous silica (KCC-1) nanospheres

    KAUST Repository

    Polshettiwar, Vivek

    2011-02-18

    Tantalizing hydrocarbons: Tantalum hydride supported on fibrous silica nanospheres (KCC-1) catalyzes, in the presence of hydrogen, the direct conversion of olefins into alkanes that have higher and lower numbers of carbon atoms (see scheme). This catalyst shows remarkable catalytic activity and stability, with excellent potential of regeneration. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Conversion of actual flue gas CO 2 via cycloaddition to propylene oxide catalyzed by a single-site, recyclable zirconium catalyst

    KAUST Repository

    Kelly, Michael J.

    2017-06-12

    A reusable zirconium-based catalyst for the cycloaddition of CO2 to propylene oxide (PO) was prepared by the surface organometallic chemistry (SOMC) methodology. Accordingly, well-defined amounts of the ZrCl4·(OEt2)2 precursor were grafted on the surface of silica dehydroxylated at 700°C (SiO2-700) and at 200°C (SiO2-200) in order to afford surface coordination compounds with different podality and chemical environment. The identity of the surface complexes was thoroughly investigated by FT-IR, elemental microanalysis and solid state NMR and applied as a recoverable and reusable heterogeneous catalyst for the title reaction using pure CO2 and flue gas samples from a cement factory. The observed catalytic activity for the isolated zirconium complexes is rationalized by means of systematic DFT calculations.

  17. Laproendoscopic single site oesophageal diverticulectomy

    Directory of Open Access Journals (Sweden)

    Chinnusamy Palanivelu

    2013-01-01

    Full Text Available Epiphrenic divericula are uncommon disorders of the lower oesophagus, which are symptomatic in only 15-20% of cases. The optimum treatment modality for such cases remains an oesophageal diverticulectomy with long myotomy with or without an antireflux operation. Recently, this is increasingly being done through the laparoscopic approach. Here we describe the first reported case of oesophageal diverticulectomy through the laparoendoscopic single site approach. A 57-year-old man presented to us with 6 months history of dysphagia and regurgitation. Patient was investigated with upper gastrointestinal (UGI endoscopy, barium swallow, CECT chest and abdomen, oesophageal manometry and 24 hour pH study. He was diagnosed to have lower oesophageal diverticulum with mildly elevated pressure readings in manometric studies with normal peristalsis. Based on his symptoms, he was taken up for surgery. A laparoscopic transhiatal oesophageal diverticulectomy with myotomy was done through laparoendoscopic single site technique. The procedure lasted 160 min. There was no intraoperative complication. Gastrograffin study was done on postoperative day 2 following which he was started on liquids. He made an uneventful recovery and was discharged on fourth day. He remained asymptomatic on follow up. Oesophageal diverticulectomy is possible through laparoendoscopic single site approach if necessary expertise is available.

  18. Hydrogenation and dehydrogenation iron pincer catalysts capable of metal-ligand cooperation by aromatization/dearomatization.

    Science.gov (United States)

    Zell, Thomas; Milstein, David

    2015-07-21

    some cases can even exceed those of state-of-the-art noble-metal catalysts. For the iron PNP systems, we describe the synthesis of the pyridine- and acridine-based PNP iron complexes and their performances and limitations in catalytic reactions, and we present studies on their reactivity with relevance to their catalytic mechanisms. In the case of the bipyridine-based PNN system, we summarize the synthesis of new complexes and describe studies on the noninnocence of the methylene position, which can be reversibly deprotonated, as well as on the noninnocence of the bipyridine unit. Overall, this Account underlines that the combination of cheap and abundant iron with ligands that are capable of metal-ligand cooperation can result in the development of novel, versatile, and efficient catalysts for atom-efficient catalytic reactions.

  19. Ni catalyst wash-coated on metal monolith with enhanced heat-transfer capability for steam reforming

    Science.gov (United States)

    Ryu, Jae-Hong; Lee, Kwan-Young; La, Howon; Kim, Hak-Joo; Yang, Jung-Il; Jung, Heon

    A commercial Ni-based catalyst is wash-coated on a monolith made of 50 μm-thick fecralloy plates. Compared with the same volume of coarsely powdered Ni catalysts, the monolith wash-coated Ni catalysts give higher methane conversion in the steam reforming reaction, especially at gas hourly space velocities (GHSV) higher than 28,000 h -1, and with no pressure drop. A higher conversion of the monolith catalyst is obtained, even though it contains a lower amount of active catalyst (3 g versus 17 g for a powdered catalyst), which indicates that the heat-transfer capability of the wash-coated Ni catalyst is significantly enhanced by the use of a metal monolith. The efficacy of the monolith catalyst is tested using a shell-and-tube type heat-exchanger reactor with 912 cm 3 of the monolith catalyst charged on to the tube side and hot combusted gas supplied to the shell side in a counter-current direction to the reactant flow. A methane conversion greater than 94% is obtained at a GHSV of 7300 h -1 and an average temperature of 640 °C. Nickel catalysts should first be reduced to become active for steam reforming. Doping a small amount (0.12 wt.%) of noble metal (Ru or Pt) in the commercial Ni catalyst renders the wash-coated catalyst as active as a pre-reduced Ni catalyst. Thus, noble metal-doped Ni appears useful for steam reforming without any pre-reduction procedure.

  20. Robotic single-site pelvic lymphadenectomy.

    Science.gov (United States)

    Tateo, Saverio; Nozza, Arrigo; Del Pezzo, Chiara; Mereu, Liliana

    2014-09-01

    To examine the feasibility of performing pelvic lymphadenectomy with robotic single site approach. Recent papers described the feasibility of robotic-single site hysterectomy [1-3] for benign and malign pathologies but only with the development of new single site 5mm instruments as the bipolar forceps, robotic single site platform can be safely utilized also for lymphadenectomy. A 65 year-old, multiparous patient with a body mass index of 22.5 and diagnosed with well differentiated adenocarcinoma of the endometrium underwent a robotic single-site peritoneal washing, total hysterectomy, bilateral adnexectomy and pelvic lymphadenectomy. The procedure was performed using the da Vinci Si Surgical System (Intuitive Surgical, Sunnyvale, CA) through a single 2,5 cm umbilical incision, with a multi-channel system and two single site robotic 5mm instruments. A 3-dimensional, HD 8.5mm endoscope and a 5mm accessory instrument were also utilized. Type I lymphonodes dissection for external iliac and obturator regions was performed [4]. Total operative time was 210 min; incision, trocar placement and docking time occurring in 12 min. Total console time was 183 min, estimated blood loss was 50 ml, no intra-operative or post-operative complications occurred. Hospital discharge occurred on post operative day 2 and total number of lymphnodes removed was 33. Difficulties in term of instrument's clashing and awkward motions have been encountered. Robotic single-site pelvic lymphadenectomy using bipolar forceps and monopolar hook is feasible. New developments are needed to improve surgical ergonomics and additional studies should be performed to explore possible benefits of this procedure. Copyright © 2014 Elsevier Inc. All rights reserved.

  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. Theoretical study of catalytic mechanism for single-site water oxidation process.

    Science.gov (United States)

    Lin, Xiangsong; Hu, Xiangqian; Concepcion, Javier J; Chen, Zuofeng; Liu, Shubin; Meyer, Thomas J; Yang, Weitao

    2012-09-25

    Water oxidation is a linchpin in solar fuels formation, and catalysis by single-site ruthenium complexes has generated significant interest in this area. Combining several theoretical tools, we have studied the entire catalytic cycle of water oxidation for a single-site catalyst starting with [Ru(II)(tpy)(bpm)(OH(2))](2+) (i.e., [Ru(II)-OH(2)](2+); tpy is 2,2':6',2''-terpyridine and bpm is 2,2'-bypyrimidine) as a representative example of a new class of single-site catalysts. The redox potentials and pK(a) calculations for the first two proton-coupled electron transfers (PCETs) from [Ru(II)-OH(2)](2+) to [Ru(IV) = O](2+) and the following electron-transfer process to [Ru(V) = O](3+) suggest that these processes can proceed readily in acidic or weakly basic conditions. The subsequent water splitting process involves two water molecules, [Ru(V) = O](3+) to generate [Ru(III)-OOH](2+), and H(3)O(+) with a low activation barrier (~10 kcal/mol). After the key O-O bond forming step in the single-site Ru catalysis, another PECT process oxidizes [Ru(III)-OOH](2+) to [Ru(IV)-OO](2+) when the pH is lower than 3.7. Two possible forms of [Ru(IV)-OO](2+), open and closed, can exist and interconvert with a low activation barrier (catalytic cycle. This understanding is helpful in the design of new catalysts for water oxidation.

  3. Real-Time Visualization of Active Species in a Single-Site Metal–Organic Framework Photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Sizhuo [Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States; Pattengale, Brian [Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States; Lee, Sungsik [X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60349, United States; Huang, Jier [Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States

    2018-02-06

    In this work, we report a new single-site photocatalyst (Co-Ru-UIO- 67(bpy)) based on a metal-organic framework platform with incorporated molecular photosensitizer and catalyst. We show that this catalyst not only demonstrates exceptional activity for light-driven H2 production but also can be recycled without loss of activity. Using the combination of optical transient absorption spectroscopy and in situ X-ray absorption spectroscopy, we not only captured the key CoI intermediate species formed after ultrafast charge transfer from the incorporated photosensitizer but also identified the rate-limiting step in the catalytic cycle, providing insight into the catalysis mechanism of these single-site metal-organic framework photocatalysts.

  4. First case of robotic laparoendoscopic single-site radical prostatectomy with single-site VesPa platform.

    Science.gov (United States)

    Mattevi, D; Luciani, L G; Vattovani, V; Chiodini, S; Puglisi, M; Malossini, G

    2017-07-07

    This study aimed at reporting our first experience with robotic laparoendoscopic single-site radical prostatectomy (R-LESS-RP) with single-site VesPa platform (Intuitive Surgical Inc.). A 68-year-old-man presenting with a cT1c adenocarcinoma Gleason Score 3 + 4 = 7 in 4/12 bilateral cores underwent a transperitoneal robotic LESS-RP with a single-site Vespa platform. Initial PSA, prostate weight, and body mass index (BMI) were 4.4 ng/ml, 45 g, and 25, respectively. Instruments and camera cross within the Single-Site port; the da Vinci System software detects and reassigns the user's hands with the instruments position. The single-site port is inserted through a 2-cm intraumbilical incision. The robotic 8.5 mm scope and two surgical curved instruments (fenestrated bipolar forceps and cautery hook) are introduced through the ports and used for most of the procedure, whereas a wristed needle driver on the right hand is used for the reconstructive steps. An additional 12 mm port (Air Seal, SurgiQuest) is placed in a midline between the umbilicus and the right iliac spine in order to facilitate table assistance during surgery and to place a drain at the end of the procedure.Operative time and blood loss were 300 min and 400 mL, respectively. The postoperative course was uneventful. The drain and the catheter were removed on days 1 and 6, respectively. The patient experienced a temporary mild stress incontinence (one pad at sixth month) and erectile dysfunction.Our first robotic laparoendoscopic single-site radical prostatectomy (R-LESS-RP) with the single-site VesPa platform was associated with acceptable operative times and perioperative outcome. This procedure is feasible without complications, provided that a proper patient selection has occurred. Limited movements together with the lack of the fourth robotic arm require a considerable expertise in robotic surgery. Some tricks can help overcome technical limitations. The Robotic LESS-RP reduces in some

  5. Single-site neural tube closure in human embryos revisited.

    Science.gov (United States)

    de Bakker, Bernadette S; Driessen, Stan; Boukens, Bastiaan J D; van den Hoff, Maurice J B; Oostra, Roelof-Jan

    2017-10-01

    Since the multi-site closure theory was first proposed in 1991 as explanation for the preferential localizations of neural tube defects, the closure of the neural tube has been debated. Although the multi-site closure theory is much cited in clinical literature, single-site closure is most apparent in literature concerning embryology. Inspired by Victor Hamburgers (1900-2001) statement that "our real teacher has been and still is the embryo, who is, incidentally, the only teacher who is always right", we decided to critically review both theories of neural tube closure. To verify the theories of closure, we studied serial histological sections of 10 mouse embryos between 8.5 and 9.5 days of gestation and 18 human embryos of the Carnegie collection between Carnegie stage 9 (19-21 days) and 13 (28-32 days). Neural tube closure was histologically defined by the neuroepithelial remodeling of the two adjoining neural fold tips in the midline. We did not observe multiple fusion sites in neither mouse nor human embryos. A meta-analysis of case reports on neural tube defects showed that defects can occur at any level of the neural axis. Our data indicate that the human neural tube fuses at a single site and, therefore, we propose to reinstate the single-site closure theory for neural tube closure. We showed that neural tube defects are not restricted to a specific location, thereby refuting the reasoning underlying the multi-site closure theory. Clin. Anat. 30:988-999, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. Laparoendoscopic single-site cholecystectomy in a pregnant patient

    Directory of Open Access Journals (Sweden)

    Ramya Ranjan Behera

    2013-01-01

    Full Text Available Feasibility and safety of laparoscopic cholecystectomy during pregnancy for patients with symptomatic or complicated gallstone disease is well established. Laparoendoscopic single-site cholecystectomy (LESS-chole is a new modality in which the entire surgery is undertaken via a transumbilical incision. We describe a 33-year-old patient who underwent a LESS-chole in the 20 th week of pregnancy for gallstone disease complicated by episodes of obstructive jaundice and acute pancreatitis. This is the first reported case of LESS-chole performed using conventional laparoscopic instruments. The technical aspects as well as the various perioperative measures utilized to undertake this procedure safely are outlined.

  7. Single-site robotic cholecystectomy: efficiency and cost analysis.

    Science.gov (United States)

    Buzad, Francis A; Corne, Louis M; Brown, Thomas C; Fagin, Randy S; Hebert, April E; Kaczmarek, Charles A; Pack, Angie N; Payne, Thomas N

    2013-09-01

    Single-incision surgery has gained in popularity, and the recent development of specialized robotic and laparoscopic instruments may remove some of the ergonomic and technical difficulties associated with this approach. However, questions of cost and efficiency remain. We prospectively collected perioperative outcome and efficiency (operative time, case volume) data for our single-site robotic cholecystectomy cases and retrospectively reviewed data for our single-incision laparoscopic cholecystectomy cases. There were no differences in patient characteristics or perioperative outcomes between the robotic (n = 20) and laparoscopic (n = 10) groups; operative times were equivalent (84.6 vs 85.5 min; p = 0.8737) and blood loss and complications were minimal. There was a higher robotic case volume, with an average of two robotic cases (range 1-4)/day vs one/day for laparoscopic cases (range 1-1; p = 0.0306). Streamlined instrument costs were essentially equivalent. Robotic single-site cholecystectomy is a safe, cost-effective alternative to single-incision laparoscopic cholecystectomy in a robot-existing model. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Direct partial oxidation of methane via single-site chemistry

    Science.gov (United States)

    Kakekhani, Arvin; Norskov, Jens

    Methane (CH4), the cheapest source of hydrocarbons, is a difficult-to-store and hard-to-convert chemical, due to strong and isotropic C-H bonds. Having a selective and efficient method to partially oxidize methane into more useful chemicals including methanol, formaldehyde and alkenes has long been an open challenge for catalysis community. The main challenge is selectivity: if a catalytic material interacts strongly with methane, sufficient to break one C-H bond, it breaks all other bonds of the derivative molecules, as well. This leads to over-oxidization to CO2. Here using density functional theory (DFT) modelings, we discuss the possibility of using defective (vacancy rich) 2-d materials e.g., MoS2 to effectively trap single transition metal atoms; thereby, creating a single-site chemistry to enhance the selectivity of methane oxidation process. A single-site chemistry leads to competition between intermediates and products for limited active sites. Our strategy is to use this as an effective means to block unwanted reaction pathways leading to over-oxidization. United States department of energy.

  9. Wegner Estimates for Sign-Changing Single Site Potentials

    Science.gov (United States)

    Veselić, Ivan

    2010-12-01

    We study Anderson and alloy-type random Schrödinger operators on ℓ2(ℤ d ) and L 2(ℝ d ). Wegner estimates are bounds on the average number of eigenvalues in an energy interval of finite box restrictions of these types of operators. For a certain class of models we prove a Wegner estimate which is linear in the volume of the box and the length of the considered energy interval. The single site potential of the Anderson/alloy-type model does not need to have fixed sign, but it needs be of a generalised step function form. The result implies the Lipschitz continuity of the integrated density of states.

  10. Intramolecular electron transfer in single-site-mutated azurins

    DEFF Research Database (Denmark)

    Farver, O; Skov, L K; Pascher, T

    1993-01-01

    . Natl. Acad. Sci. U.S.A. 86, 6968-6972]. The RSSR- radical produced in the above reaction was reoxidized in a slower intramolecular electron-transfer process (30-70 s-1 at 298 K) concomitant with a further reduction of the Cu(II) ion. The temperature dependence of the latter rates was determined...... and used to derive information on the possible effects of the mutations. The substitution of residue Phe114, situated on the opposite side of Cu relative to the disulfide, by Ala resulted in a rate increase by a factor of almost 2. By assuming that this effect is only due to an increase in driving force......Single-site mutants of the blue, single-copper protein, azurin, from Pseudomonas aeruginosa were reduced by CO2- radicals in pulse radiolysis experiments. The single disulfide group was reduced directly by CO2- with rates similar to those of the native protein [Farver, O., & Pecht, I. (1989) Proc...

  11. Laparoendoscopic single-site adnexal surgery: Preliminary Indian experience

    Directory of Open Access Journals (Sweden)

    Smitha Balusamy

    2017-01-01

    Full Text Available Introduction: Laparoendoscopic single-site surgery (LESS is an emerging technique in gynaecology. The proposed advantages of the LESS include better cosmesis and reduction in pain. We report our preliminary experience with LESS in the treatment of adnexal pathology. Materials and Methods: After a preoperative workup, LESS was offered to 37 patients between July 2009 and April 2015. All the procedures were carried out through a 2–2.5 cm transumbilical incision using conventional laparoscopic instruments. A single-incision, multiport (SIMP approach (utilising one 7 mm and two 5 mm ports was used in 27 patients and a homemade glove port (HMGP was utilised in ten patients. All the specimens were extracted after placement in a plastic bag or inside the glove port avoiding contact with the wound. Umbilical fascial incisions were meticulously closed with non-absorbable sutures. Results: Two patients with a history of previous abdominal surgery required omental adhesiolysis. Seventeen patients with breast cancer underwent bilateral salpingo-oophorectomy, ten had ovarian cystectomy (6 had cystadenoma, 2 had endometriotic cysts and 2 had dermoid cyst, six had excision of paraovarian cysts (one along with partial salpingectomy and four with ruptured ectopic pregnancy underwent salpingectomy. LESS was completed in all but one patient, who required insertion of an additional 5 mm port. There were no intra- or post-operative complications. Conclusions: Our experience confirms the feasibility and safety of LESS in a variety of benign adnexal pathology. Both the SIMP and HMGP approaches seem comparable. Performing LESS without the use of specialised access ports or instruments makes it cost effective and suitable for wider application.

  12. Well-defined silica supported aluminum hydride: another step towards the utopian single site dream?

    Science.gov (United States)

    Werghi, Baraa; Bendjeriou-Sedjerari, Anissa; Sofack-Kreutzer, Julien; Jedidi, Abdesslem; Abou-Hamad, Edy; Cavallo, Luigi; Basset, Jean-Marie

    2015-10-01

    processes occur by opening of a strained siloxane bridge, Si-O-Si but with two different mechanisms, showing that the reality of "single site" catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O-Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a β-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al-H bond and a O-Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10 -5 mbar) generates Al-H through a β-H elimination of isobutyl fragment. These supported well-defined Al-H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27 Al- 1 H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system.

  13. Single-site robotic surgery in gynecologic cancer: a pilot study

    OpenAIRE

    Yoo, Ha-Na; Kim, Tae-Joong; Lee, Yoo-Young; Choi, Chel Hun; Lee, Jeong-Won; Bae, Duk-Soo; Kim, Byoung-Gie

    2015-01-01

    Objective To discuss the feasibility of single-site robotic surgery for benign gynecologic tumors and early stage gynecologic cancers. Methods In this single institution, prospective analysis, we analyzed six patients who had undergone single-site robotic surgery between December 2013 and August 2014. Surgery was performed using the da Vinci Si Surgical System. Patient characteristics and surgical outcomes were analyzed. Results Single-site robotic surgery was performed successfully in all si...

  14. Miniature in vivo robot for laparoendoscopic single-site surgery.

    Science.gov (United States)

    Dolghi, Oleg; Strabala, Kyle W; Wortman, Tyler D; Goede, Matthew R; Farritor, Shane M; Oleynikov, Dmitry

    2011-10-01

    The aim of this study was to develop a multidexterous robot capable of generating the required forces and speeds to perform surgical tasks intra-abdominally. Current laparoscopic surgical robots are expensive, bulky, and fundamentally constrained by a small entry incision. A new approach to minimally invasive surgery places the robot completely within the patient. Miniature in vivo robots may allow surgeons to overcome current laparoscopic constraints such as dexterity, orientation, and visualization. A collaborative research group from the Department of Surgery at the University of Nebraska Medical Center and the College of Engineering at the University of Nebraska-Lincoln designed and built a surgical robot prototype capable of performing specific surgical tasks within the peritoneal cavity. The basic robotic design consists of two arms each connected to a central body. Each arm has three degrees of freedom and rotational shoulder and elbow joints. This combination allows a surgeon to grasp, manipulate, cauterize, and perform intracorporeal suturing. The robot's workspace is a hollow hemisphere with an inner radius of 75 mm and an outer radius of 205 mm. Its versatility was demonstrated in four procedures performed in a porcine model: cholecystectomy, partial colectomy, abdominal exploration, and intracorporeal suturing. Miniature in vivo robots have the potential to address the limitations of using articulated instrumentation to perform advanced laparoscopic surgical procedures. Once inserted into the peritoneal cavity, the robot provides a stable platform for visualization with sufficient dexterity and speed to perform surgical tasks from multiple orientations and workspaces.

  15. Single-site Lennard-Jones models via polynomial chaos surrogates of Monte Carlo molecular simulation

    KAUST Repository

    Kadoura, Ahmad Salim

    2016-06-01

    In this work, two Polynomial Chaos (PC) surrogates were generated to reproduce Monte Carlo (MC) molecular simulation results of the canonical (single-phase) and the NVT-Gibbs (two-phase) ensembles for a system of normalized structureless Lennard-Jones (LJ) particles. The main advantage of such surrogates, once generated, is the capability of accurately computing the needed thermodynamic quantities in a few seconds, thus efficiently replacing the computationally expensive MC molecular simulations. Benefiting from the tremendous computational time reduction, the PC surrogates were used to conduct large-scale optimization in order to propose single-site LJ models for several simple molecules. Experimental data, a set of supercritical isotherms, and part of the two-phase envelope, of several pure components were used for tuning the LJ parameters (ε, σ). Based on the conducted optimization, excellent fit was obtained for different noble gases (Ar, Kr, and Xe) and other small molecules (CH4, N2, and CO). On the other hand, due to the simplicity of the LJ model used, dramatic deviations between simulation and experimental data were observed, especially in the two-phase region, for more complex molecules such as CO2 and C2 H6.

  16. Compact teleoperated laparoendoscopic single-site robotic surgical system: Kinematics, control, and operation.

    Science.gov (United States)

    Isaac-Lowry, Oran Jacob; Okamoto, Steele; Pedram, Sahba Aghajani; Woo, Russell; Berkelman, Peter

    2017-12-01

    To date a variety of teleoperated surgical robotic systems have been developed to improve a surgeon's ability to perform demanding single-port procedures. However typical large systems are bulky, expensive, and afford limited angular motion, while smaller designs suffer complications arising from limited motion range, speed, and force generation. This work was to develop and validate a simple, compact, low cost single site teleoperated laparoendoscopic surgical robotic system, with demonstrated capability to carry out basic surgical procedures. This system builds upon previous work done at the University of Hawaii at Manoa and includes instrument and endoscope manipulators as well as compact articulated instruments designed to overcome single incision geometry complications. A robotic endoscope holder was used for the base, with an added support frame for teleoperated manipulators and instruments fabricated mostly from 3D printed parts. Kinematics and control methods were formulated for the novel manipulator configuration. Trajectory following results from an optical motion tracker and sample task performance results are presented. Results indicate that the system has successfully met the goal of basic surgical functionality while minimizing physical size, complexity, and cost. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Well-Defined Silica Supported Aluminum Hydride: Another Step Towards the Utopian Single Site Dream?

    KAUST Repository

    Werghi, Baraa

    2015-07-17

    Reaction of triisobutylaluminum with SBA15700 at room temperature occurs by two parallel pathways involving either silanol or siloxane bridges. It leads to the formation of a well-defined bipodal [(≡SiO)2Al-CH2CH(CH3)2] 1a, silicon isobutyl [≡Si-CH2CH(CH3)2] 1b and a silicon hydride [≡Si-H] 1c. Their structural identity was characterized by FT-IR and advance solid-state NMR spectroscopies (1H, 13C, 29Si, 27Al and 2D multiple quantum), elemental and gas phase analysis, and DFT calculations. The reaction involves the formation of a highly reactive monopodal intermediate: [≡SiO-Al-[CH2CH(CH3)2]2], with evolution of isobutane. This intermediate undergoes two parallel routes: Transfer of either one isobutyl fragment or of one hydride to an adjacent silicon atom. Both processes occur by opening of a strained siloxane bridge, ≡Si-O-Si≡ but with two different mechanisms, showing that the reality of “single site” catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O-Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a ß-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al-H bond and a O-Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10-5 mbar) generates Al-H through a ß-H elimination of isobutyl fragment. These supported well-defined Al-H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27Al–1H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system.

  18. O-O bond formation in ruthenium-catalyzed water oxidation: single-site nucleophilic attack vs. O-O radical coupling.

    Science.gov (United States)

    Shaffer, David W; Xie, Yan; Concepcion, Javier J

    2017-10-16

    In this review we discuss at the mechanistic level the different steps involved in water oxidation catalysis with ruthenium-based molecular catalysts. We have chosen to focus on ruthenium-based catalysts to provide a more coherent discussion and because of the availability of detailed mechanistic studies for these systems but many of the aspects presented in this review are applicable to other systems as well. The water oxidation cycle has been divided in four major steps: water oxidative activation, O-O bond formation, oxidative activation of peroxide intermediates, and O 2 evolution. A significant portion of the review is dedicated to the O-O bond formation step as the key step in water oxidation catalysis. The two main pathways to accomplish this step, single-site water nucleophilic attack and O-O radical coupling, are discussed in detail and compared in terms of their potential use in photoelectrochemical cells for solar fuels generation.

  19. Quantifying the cognitive cost of laparo-endoscopic single-site surgeries: Gaze-based indices.

    Science.gov (United States)

    Di Stasi, Leandro L; Díaz-Piedra, Carolina; Ruiz-Rabelo, Juan Francisco; Rieiro, Héctor; Sanchez Carrion, Jose M; Catena, Andrés

    2017-11-01

    Despite the growing interest concerning the laparo-endoscopic single-site surgery (LESS) procedure, LESS presents multiple difficulties and challenges that are likely to increase the surgeon's cognitive cost, in terms of both cognitive load and performance. Nevertheless, there is currently no objective index capable of assessing the surgeon cognitive cost while performing LESS. We assessed if gaze-based indices might offer unique and unbiased measures to quantify LESS complexity and its cognitive cost. We expect that the assessment of surgeon's cognitive cost to improve patient safety by measuring fitness-for-duty and reducing surgeons overload. Using a wearable eye tracker device, we measured gaze entropy and velocity of surgical trainees and attending surgeons during two surgical procedures (LESS vs. multiport laparoscopy surgery [MPS]). None of the participants had previous experience with LESS. They performed two exercises with different complexity levels (Low: Pattern Cut vs. High: Peg Transfer). We also collected performance and subjective data. LESS caused higher cognitive demand than MPS, as indicated by increased gaze entropy in both surgical trainees and attending surgeons (exploration pattern became more random). Furthermore, gaze velocity was higher (exploration pattern became more rapid) for the LESS procedure independently of the surgeon's expertise. Perceived task complexity and laparoscopic accuracy confirmed gaze-based results. Gaze-based indices have great potential as objective and non-intrusive measures to assess surgeons' cognitive cost and fitness-for-duty. Furthermore, gaze-based indices might play a relevant role in defining future guidelines on surgeons' examinations to mark their achievements during the entire training (e.g. analyzing surgical learning curves). Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Selective alkane activation with single-site atoms on amorphous support

    Science.gov (United States)

    Hock, Adam S.; Schweitzer, Neil M.; Miller, Jeffrey T.; Hu, Bo

    2015-11-24

    The present invention relates generally to catalysts and methods for use in olefin production. More particularly, the present invention relates to novel amorphously supported single-center, Lewis acid metal ions and use of the same as catalysts.

  1. Transumbilical laparoendoscopic single-site surgery versus conventional laparoscopy for the resection of retroperitoneal paragangliomas.

    Science.gov (United States)

    Xu, Weifeng; Li, Hanzhong; Ji, Zhigang; Yan, Weigang; Zhang, Yushi; Zhang, Xuebin; Li, Qian

    2015-09-01

    To compare transumbilical laparoendoscopic single-site surgery with conventional laparoscopy for the resection of retroperitoneal paragangliomas. In the present case-control study, we compared 11 transumbilical laparoendoscopic single-site surgery procedures with 22 conventional laparoscopy procedures carried out to treat retroperitoneal paragangliomas between June 2004 and October 2013 at Peking Union Medical Hospital, Beijing, China. Operative time, estimated intraoperative blood loss, blood transfusions, intraoperative hypertension, intraoperative hypotension, highest intraoperative systolic blood pressure, lowest intraoperative systolic blood pressure, postoperative fatigue time, postoperative systematic inflammation reaction syndrome, 24-h postoperative visual analog scale scores, postoperative hospital stay duration, and postoperative complications were recorded and analyzed. There were no significant differences in patient characteristics. All surgical procedures were successfully completed in both groups. Minor complications occurred in one case in the laparoendoscopic single-site surgery group and in two cases in the conventional laparoscopy group. In the laparoendoscopic single-site surgery group, the operative time was longer than that in the conventional laparoscopy group (P = 0.001). There were no significant differences in terms of intraoperative hypertension, intraoperative hypotension, highest intraoperative systolic blood pressure, lowest intraoperative systolic blood pressure, estimated blood loss, postoperative fatigue time, postoperative hospital stay or systematic inflammation reaction syndrome between the two groups. The 24-h postoperative visual analog scale score was lower in the laparoendoscopic single-site surgery group (P = 0.002). No recurrence or metastases were observed over the duration of the postoperative follow up. In properly selected patients, transumbilical laparoendoscopic single-site surgery is a feasible, safe and effective

  2. Mechanistic studies aimed at the development of single site metal alkoxide catalysts for the production of polyoxygenates from renewable resources.

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, Malcolm H. [The Ohio State Univ., Columbus, OH (United States)

    2015-12-15

    The work proposed herein follows on directly from the existing 3 year grant and the request for funding is for 12 months to allow completion of this work and graduation of current students supported by DOE. The three primary projects are as follows. 1.) A comparative study of the reactivity of LMg(OR) (solvent), where L= a β-diiminate or pyrromethene ligand, in the ring-opening of cyclic esters. 2.) The homopolymerization of expoxides, particularly propylene oxide and styrene oxide, and their copolymerizations with carbon dioxide or organic anhydrides to yield polycarbonates or polyesters, respectively. 3.) The development of well-defined bismuth (III) complexes for ring-opening polymerizations that are tolerant of both air and water. In each of these topics special emphasis is placed on developing a detailed mechanistic understanding of the ring-opening event and how this is modified by the employment of specific metal and ligand combinations. This document also provides a report on findings of the past grant period that are not yet in the public domain/published and shows how the proposed work will bring the original project to conclusion.

  3. Redox-active on-surface polymerization of single-site divalent cations from pure metals by a ketone-functionalized phenanthroline

    Energy Technology Data Exchange (ETDEWEB)

    Skomski, Daniel; Tempas, Christopher D.; Bukowski, Gregory S.; Smith, Kevin A.; Tait, Steven L., E-mail: tait@indiana.edu [Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, Indiana 47405 (United States)

    2015-03-14

    Metallic iron, chromium, or platinum mixing with a ketone-functionalized phenanthroline ligand on a single crystal gold surface demonstrates redox activity to a well-defined oxidation state and assembly into thermally stable, one dimensional, polymeric chains. The diverging ligand geometry incorporates redox-active sub-units and bi-dentate binding sites. The gold surface provides a stable adsorption environment and directs growth of the polymeric chains, but is inert with regard to the redox chemistry. These systems are characterized by scanning tunnelling microscopy, non-contact atomic force microscopy, and X-ray photoelectron spectroscopy under ultra-high vacuum conditions. The relative propensity of the metals to interact with the ketone group is examined, and it is found that Fe and Cr more readily complex the ligand than Pt. The formation and stabilization of well-defined transition metal single-sites at surfaces may open new routes to achieve higher selectivity in heterogeneous catalysts.

  4. Well-defined single-site monohydride silica-supported zirconium from azazirconacyclopropane

    KAUST Repository

    Hamzaoui, Bilel

    2015-01-13

    The silica-supported azazirconacyclopropane ≡SiOZr(HNMe2)(η2-NMeCH2)(NMe2) (1) leads exclusively under hydrogenolysis conditions (H2, 150°C) to the single-site monopodal monohydride silica-supported zirconium species ≡SiOZr(HNMe2)(NMe2)2H (2). Reactivity studies by contacting compound 2 with ethylene, hydrogen/ethylene, propene, or hydrogen/propene, at a temperature of 200°C revealed alkene hydrogenation.

  5. Housing retention in single-site housing first for chronically homeless individuals with severe alcohol problems.

    Science.gov (United States)

    Collins, Susan E; Malone, Daniel K; Clifasefi, Seema L

    2013-12-01

    We studied housing retention and its predictors in the single-site Housing First model. Participants (n = 111) were chronically homeless people with severe alcohol problems who lived in a single-site Housing First program and participated in a larger nonrandomized controlled trial (2005-2008) conducted in Seattle, Washington. At baseline, participants responded to self-report questionnaires assessing demographic, illness burden, alcohol and other drug use, and psychiatric variables. Housing status was recorded over 2 years. Participants were interested in housing, although a sizable minority did not believe they would be able to maintain abstinence-based housing. Only 23% of participants returned to homelessness during the 2-year follow-up. Commonly cited risk factors--alcohol and other drug use, illness burden, psychiatric symptoms, and homelessness history--did not predict resumed homelessness. Active drinkers were more likely to stay in this housing project than nondrinkers. We found that single-site Housing First programming fills a gap in housing options for chronically homeless people with severe alcohol problems.

  6. Housing Retention in Single-Site Housing First for Chronically Homeless Individuals With Severe Alcohol Problems

    Science.gov (United States)

    Malone, Daniel K.; Clifasefi, Seema L.

    2013-01-01

    Objectives. We studied housing retention and its predictors in the single-site Housing First model. Methods. Participants (n = 111) were chronically homeless people with severe alcohol problems who lived in a single-site Housing First program and participated in a larger nonrandomized controlled trial (2005–2008) conducted in Seattle, Washington. At baseline, participants responded to self-report questionnaires assessing demographic, illness burden, alcohol and other drug use, and psychiatric variables. Housing status was recorded over 2 years. Results. Participants were interested in housing, although a sizable minority did not believe they would be able to maintain abstinence-based housing. Only 23% of participants returned to homelessness during the 2-year follow-up. Commonly cited risk factors—alcohol and other drug use, illness burden, psychiatric symptoms, and homelessness history—did not predict resumed homelessness. Active drinkers were more likely to stay in this housing project than nondrinkers. Conclusions. We found that single-site Housing First programming fills a gap in housing options for chronically homeless people with severe alcohol problems. PMID:24148063

  7. Capability Paternalism

    NARCIS (Netherlands)

    Claassen, R.J.G.

    A capability approach prescribes paternalist government actions to the extent that it requires the promotion of specific functionings, instead of the corresponding capabilities. Capability theorists have argued that their theories do not have much of these paternalist implications, since promoting

  8. Laparoendoscopic Single-Site Surgery (LESS for a Large Ovarian Tumour: First Clinical Case Report

    Directory of Open Access Journals (Sweden)

    Yao Dong Chua

    2011-01-01

    Main Outcome Measure(s. Conversion to standard laparoscopic technique or laparotomy, estimated blood loss, operative time , extent of scarring, occurrence of intra- and perioperative surgical complications, technical adequacy, and clinical outcome. Result(s. No conversion to standard laparoscopic technique or laparotomy, and no intraoperative or postoperative complications were observed. Total operative time was 99 minutes. The patient was discharged home on postoperative day one. Conclusion(s. Laparoendoscopic single-site bilateral salpingo-oophorectomy of a large ovarian tumour is feasible with standard laparoscopic instruments. It is safe and effective, with good results in terms of excellent cosmesis and minimal postoperative pain.

  9. On multi-site damage identification using single-site training data

    Science.gov (United States)

    Barthorpe, R. J.; Manson, G.; Worden, K.

    2017-11-01

    This paper proposes a methodology for developing multi-site damage location systems for engineering structures that can be trained using single-site damaged state data only. The methodology involves training a sequence of binary classifiers based upon single-site damage data and combining the developed classifiers into a robust multi-class damage locator. In this way, the multi-site damage identification problem may be decomposed into a sequence of binary decisions. In this paper Support Vector Classifiers are adopted as the means of making these binary decisions. The proposed methodology represents an advancement on the state of the art in the field of multi-site damage identification which require either: (1) full damaged state data from single- and multi-site damage cases or (2) the development of a physics-based model to make multi-site model predictions. The potential benefit of the proposed methodology is that a significantly reduced number of recorded damage states may be required in order to train a multi-site damage locator without recourse to physics-based model predictions. In this paper it is first demonstrated that Support Vector Classification represents an appropriate approach to the multi-site damage location problem, with methods for combining binary classifiers discussed. Next, the proposed methodology is demonstrated and evaluated through application to a real engineering structure - a Piper Tomahawk trainer aircraft wing - with its performance compared to classifiers trained using the full damaged-state dataset.

  10. Single-site ventricular pacing via the coronary sinus in patients with tricuspid valve disease.

    Science.gov (United States)

    Noheria, Amit; van Zyl, Martin; Scott, Luis R; Srivathsan, Komandoor; Madhavan, Malini; Asirvatham, Samuel J; McLeod, Christopher J

    2017-03-01

    To evaluate coronary sinus single-site (CSSS) left ventricular pacing in adult patients with normal left ventricular ejection fraction (LVEF) when traditional right ventricular lead implantation is not feasible or is contraindicated. We performed a retrospective analysis of 23 patients with tricuspid valve surgery/disease who received a CSSS ventricular pacing lead to avoid crossing the tricuspid valve. Two matched control populations were obtained from patients receiving (i) conventional right ventricular single-site (RVSS) leads and (ii) coronary sinus leads for cardiac resynchronization therapy (CSCRT). Main outcomes of interest were lead stability, electrical lead parameters and change in LVEF during long-term follow-up. Successful CSSS pacing was accomplished in all 23 patients without any procedural complications. During the 5.3 ± 2.8-year follow-up 22/23 (95.7%) leads were functional with stable pacing and sensing parameters, and 1/23 (4.3%) was extracted for unrelated reasons. Compared to CSSS leads, the lead revision/abandonment was similar with RVSS leads (Hazard ratio (HR) 0.87, 95% confidence interval (CI) 0.03, 22.0), but was higher with CSCRT leads (HR 7.41, 95% CI 1.30, 139.0). There was no difference in change in LVEF between CSSS and RVSS groups (-2.4 ± 11.0 vs. 1.5 ± 12.8, P = 0.76), but LVEF improved in CSCRT group (11.2 ± 16.5%, P = 0.002). Fluoroscopy times were longer during implantation of CSSS compared to RVSS leads (25.6 ± 24.6 min vs. 12.3 ± 18.6 min, P = 0.049). In patients with normal LVEF, single-site ventricular pacing via the coronary sinus is a feasible, safe and reliable alternative to right ventricular pacing. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

  11. Left Transperitoneal Adrenalectomy with a Laparoendoscopic Single-Site Surgery Combined Technique: Initial Case Reports

    Directory of Open Access Journals (Sweden)

    Yasuhiro Sumino

    2011-01-01

    Full Text Available Laparoendoscopic single-site surgery (LESS is a step toward the development of minimally invasive surgery. It is initially difficult for surgeons with limited experience to perform the surgery. We describe two cases of left adrenalectomy with a LESS combined with the addition of an accessory port. After a 2.5-cm skin incision was made at the level of the paraumbilicus to insert the primary 12-mm trocar for the laparoscope, a 5-mm nonbladed trocar was placed through the skin incision side-by-side with the primary trocar. A second 3-mm nonbladed trocar was then placed along the anterior axillary line; a multichannel trocar was not used as a single port. Both adrenalectomies were completed successfully. In patients with a minor adrenal tumor, a combined technique using LESS and an additional port is easier than LESS alone and may, therefore, be a bridge between the conventional laparoscopic approach and LESS.

  12. Management of gallbladder duplication using a single-site robotic-assisted approach: a case study.

    Science.gov (United States)

    Boyle, Melanie Adams; Kaplin, Aviva Wallace; Kushnir, Leon; Montero-Pearson, Per

    2016-06-01

    Gallbladder duplication is a rare congenital anomaly. Here, we describe a 29-year-old female who presents with classic symptoms of biliary colic. A duplicated gallbladder was recognized on preoperative ultrasound. This case report reviews a single-site robotic-assisted cholecystectomy with a cystic duct duplication. The patient underwent the surgery without complication. Due to the aberrant anatomy of the cystic triangle, it was decided to mobilize the gallbladder in a dome-down fashion. True gallbladder duplication can be categorized according to cystic duct orientation based on Boyden's classification. Preoperative diagnosis is essential to prevent surgical complications. A laparoscopic approach can be carried out safely in the hands of a skilled surgeon. This case report shows that the robotic-assisted surgical approach is a viable and safe alternative.

  13. Single-Site Tetracoordinated Aluminum Hydride Supported on Mesoporous Silica. From Dream to Reality!

    KAUST Repository

    Werghi, Baraa

    2016-09-26

    The reaction of mesoporous silica (SBA15) dehydroxylated at 700 °C with diisobutylaluminum hydride, i-Bu2AlH, gives after thermal treatment a single-site tetrahedral aluminum hydride with high selectivity. The starting aluminum isobutyl and the final aluminum hydride have been fully characterized by FT-IR, advanced SS NMR spectroscopy (1H, 13C, multiple quanta (MQ) 2D 1H-1H, and 27Al), and elemental analysis, while DFT calculations provide a rationalization of the occurring reactivity. Trimeric i-Bu2AlH reacts selectively with surface silanols without affecting the siloxane bridges. Its analogous hydride catalyzes ethylene polymerization. Indeed, catalytic tests show that this single aluminum hydride site is active in the production of a high-density polyethylene (HDPE). © 2016 American Chemical Society.

  14. Patients' perceptions of laparoendoscopic single-site surgery: the cosmetic effect.

    Science.gov (United States)

    Golkar, Farhaad C; Ross, Sharona B; Sperry, Steffanie; Vice, Michelle; Luberice, Kenneth; Donn, Natalie; Morton, Connor; Hernandez, Jonathan M; Rosemurgy, Alexander S

    2012-11-01

    Laparoendoscopic single-site (LESS) surgery can be performed without apparent scarring, while maintaining the salutary benefits of conventional laparoscopic surgery. The purpose of this study was to compare patients' preoperative and postoperative perceptions of LESS surgery. Before and after undergoing LESS surgery, 120 patients were given questionnaires; their responses were assimilated and analyzed. Of 120 patients, 62% were female (age, 52 ± 16.6 y), and 54% had prior abdominal surgery. Preoperatively, women and older patients reported heightened appearance dissatisfaction. Preoperatively, most patients would not accept more risk, pain, surgery/recovery times, and/or costs than associated with standard laparoscopy. Postoperatively, patients reported increased satisfaction in their overall and abdominal region appearance. Satisfaction was noted by 92%; satisfaction was related significantly to scar appearance and cosmesis. Preoperatively, patients were most concerned with safety; postoperatively, patients' concerns shifted to cosmetic outcome. LESS surgery provides an opportunity for improved patient satisfaction. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Insufficient joint forces of first-generation articulating instruments for laparoendoscopic single-site surgery.

    Science.gov (United States)

    Jeong, Chang Wook; Kim, Sung Hoon; Kim, Hyung Tae; Jeong, Seong Jin; Hong, Sung Kyu; Byun, Seok-Soo; Lee, Sang Eun

    2013-10-01

    The current articulating instruments used in laparoendoscopic single-site surgery do not appear to provide the joint forces required. Thus, we measured the joint forces of first-generation articulating laparoscopic instruments. To compare these forces with those necessary in the surgical context, we evaluated the forces sufficient to produce secure surgical ties in an animal model. The articulating instruments tested were Laparo-Angle (Cambridge Endoscopic Devices Inc, Framingham, MA), RealHand (Novare Surgical Systems Inc, Cupertino, CA), and Roticulator (Covidien Inc, Mansfield, MA). For each, we measured the angle between the end-effector and the shaft in proportion to the articulating force using a push-pull gauge. Two fixed-position configurations of the instruments were predetermined: the neutral and the fully articulated positions. The forces required to secure surgical ties for the ureter, renal artery, and renal vein were evaluated using kidneys harvested from a female pig. The bending forces required to bend from the neutral position to 30° were 5.6 ± 1.2 and 4.7 ± 1.0 N with the Laparo-Angle and RealHand, respectively. Furthermore, the slippage forces in the fully articulated state were 1.8 ± 0.3, 1.6 ± 0.2, and 1.5 ± 0.2 N in the above order. In contrast, the mean forces to produce surgical ties of the ureter, renal artery, and renal vein were 14.5 ± 2.3, 11.5 ± 0.8, and 10.3 ± 2.3 N, respectively. The joint forces of first-generation articulating instruments for laparoendoscopic single-site surgery are not sufficient to meet the usual operative needs. Improved articulating instruments with greater articulating forces should be developed.

  16. Minimal invasive single-site surgery in colorectal procedures: Current state of the art

    Directory of Open Access Journals (Sweden)

    Diana Michele

    2011-01-01

    Full Text Available Background: Minimally invasive single-site (MISS surgery has recently been applied to colorectal surgery. We aimed to assess the current state of the art and the adequacy of preliminary oncological results. Methods: We performed a systematic review of the literature using Pubmed, Medline, SCOPUS and Web of Science databases. Keywords used were "Single Port" or "Single-Incision" or "LaparoEndoscopic Single Site" or "SILS™" and "Colon" or "Colorectal" and "Surgery". Results: Twenty-nine articles on colorectal MISS surgery have been published from July 2008 to July 2010, presenting data on 149 patients. One study reported analgesic requirement. The final incision length ranged from 2.5 to 8 cm. Only two studies reported fascial incision length. There were two port site hernias in a series of 13 patients (15.38%. Two "fully laparoscopic" MISS procedures with preparation and achievement of the anastomosis completely intracorporeally are reported. Future site of ileostomy was used as the sole access for the procedures in three studies. Lymph node harvesting, resection margins and length of specimen were sufficient in oncological cases. Conclusions: MISS colorectal surgery is a challenging procedure that seems to be safe and feasible, but the existing clinical evidence is limited. In selected cases, and especially when an ileostomy is planned, colorectal surgery may be an ideal indication for MISS surgery leading to a no-scar surgery. Despite preliminary oncological results showing the feasibility of MISS surgery, we want to stress the need to standardize the technique and carefully evaluate its application in oncosurgery under ethical committee control.

  17. Catalysts preparing

    International Nuclear Information System (INIS)

    Normatov, I.Sh.; Mirsaidov, U.M.

    2003-01-01

    One of the base area of zeolites industry using is catalysis. The catalytic properties of zeolites use in the carbonated reactions in the petrochemistry. Last years zeolite catalysts use in oxidative-reduction processes

  18. Lunar CATALYST

    Data.gov (United States)

    National Aeronautics and Space Administration — Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) is a NASA initiative to encourage the development of U.S. private-sector robotic lunar...

  19. Photo-oxidation catalysts

    Science.gov (United States)

    Pitts, J Roland [Lakewood, CO; Liu, Ping [Irvine, CA; Smith, R Davis [Golden, CO

    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.

  20. Catalysts for Dehydrogenation of ammonia boranes

    Energy Technology Data Exchange (ETDEWEB)

    Heinekey, Dennis M. [Univ. of Washington, Seattle, WA (United States)

    2009-10-31

    Several effective homogeneous catalysts for the dehydrogenation of amine boranes have been developed. The best catalyst uses an iridium complex, and is capable of dehydrogenating H3NBH3 (AB) and CH3NH2BH3 (MeAB) at comparable rates. Thermodynamic measurements using this catalyst demonstrate that the dehydrogenation of AB and MeAB is substantially exothermic, which has important implications for regeneration.

  1. Capability ethics

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2012-01-01

    textabstractThe capability approach is one of the most recent additions to the landscape of normative theories in ethics and political philosophy. Yet in its present stage of development, the capability approach is not a full-blown normative theory, in contrast to utilitarianism, deontological

  2. Evidence that adaptation in Drosophila is not limited by mutation at single sites.

    Directory of Open Access Journals (Sweden)

    Talia Karasov

    2010-06-01

    Full Text Available Adaptation in eukaryotes is generally assumed to be mutation-limited because of small effective population sizes. This view is difficult to reconcile, however, with the observation that adaptation to anthropogenic changes, such as the introduction of pesticides, can occur very rapidly. Here we investigate adaptation at a key insecticide resistance locus (Ace in Drosophila melanogaster and show that multiple simple and complex resistance alleles evolved quickly and repeatedly within individual populations. Our results imply that the current effective population size of modern D. melanogaster populations is likely to be substantially larger (> or = 100-fold than commonly believed. This discrepancy arises because estimates of the effective population size are generally derived from levels of standing variation and thus reveal long-term population dynamics dominated by sharp--even if infrequent--bottlenecks. The short-term effective population sizes relevant for strong adaptation, on the other hand, might be much closer to census population sizes. Adaptation in Drosophila may therefore not be limited by waiting for mutations at single sites, and complex adaptive alleles can be generated quickly without fixation of intermediate states. Adaptive events should also commonly involve the simultaneous rise in frequency of independently generated adaptive mutations. These so-called soft sweeps have very distinct effects on the linked neutral polymorphisms compared to the standard hard sweeps in mutation-limited scenarios. Methods for the mapping of adaptive mutations or association mapping of evolutionarily relevant mutations may thus need to be reconsidered.

  3. Laparoendoscopic Single-Site Plus One-Port Donor Nephrectomy: Analysis of 169 Cases.

    Science.gov (United States)

    Cho, Hyuk Jin; Choi, Sae Woong; Kim, Kang Sup; Park, Yong Hyun; Bae, Woong Jin; Hong, Sung-Hoo; Lee, Ji Youl; Kim, Sae Woong; Hwang, Tae-Kon

    2015-08-01

    To present our experience with laparoendoscopic single-site plus one-port donor nephrectomy (LESSOP-DN) and compare the outcomes with laparoscopic donor nephrectomy (LDN). Prospectively collected data from 169 consecutive LESSOP-DNs and 83 LDNs performed by a single surgeon in the same time period were analyzed retrospectively. No differences in mean operative time (136 versus 130 minutes; P=.15), warm ischemia time (3.4 versus 3.5 minutes; P=.42), blood loss (50 versus 45 mL; P=.41), transfusion rates (0 versus 1 case), hospital stay (4.0 versus 3.9 days; P=.48), or overall complication rate (12.0% versus 7.7%; P=.25) were observed between the LDN and LESSOP-DN groups. The LESSOP-DN group had a shorter time to return to 100% recovery (39 versus 74 days; Pa smaller surgical incision (5.5 versus 8.2 cm; Pgroup. Renal function of the recipient based on estimated glomerular filtration rate at 1 and 3 months was similar between the groups. Health-related quality of life (QOL) was significantly higher in the LESSOP-DN group in four domains of the health survey than in the LDN group. LESSOP-DN might be associated with smaller surgical incision, improved cosmetic satisfaction, less time to recovery, less analgesic requirement, improved donor QOL, and equivalent recipient graft function.

  4. A comparative study of multiport versus laparoendoscopic single-site adrenalectomy for benign adrenal tumors.

    Science.gov (United States)

    Lin, Victor Chia-Hsiang; Tsai, Yao-Chou; Chung, Shiu-Dong; Li, Tin Chou; Ho, Chen-Hsun; Jaw, Fu-Shan; Tai, Huai-Ching; Yu, Hong-Jeng

    2012-04-01

    The safety and feasibility of laparoendoscopic single-site (LESS) adrenalectomy for benign adrenal lesions was proved in early clinical series. However, the advantages of LESS over multiport laparoscopic adrenalectomy still are under investigation. Since October 2009, the authors have prospectively performed LESS retroperitoneal adrenalectomy for 21 consecutive patients with benign adrenal tumors (LESS group). Another 28 patients with benign adrenal tumors were prospectively collected between June 2006 and October 2009 and served as a multiport laparoscopic adrenalectomy group. The patients' demographic data, operating time, estimated blood loss, peri- and postoperative complications, and short-term outcome were collected for further analysis. The demographic data were comparable between the two groups in terms of the patient age, gender, body mass index (BMI), laterality, diagnosis, and resected specimen weight. No major complication or mortality occurred in either group. Neither group had any conversions. No differences were observed between the two groups in terms of intraoperative hemodynamic status or peri- or postoperative complications. The LESS patients had quicker resumption of oral intake (0.18 vs 1 day; p benign adrenal tumors. In addition, LESS adrenalectomy provides short-term convalescence advantages over multiport laparoscopic adrenalectomy.

  5. Laparoendoscopic single-site surgery in gynaecology: A new frontier in minimally invasive surgery

    Directory of Open Access Journals (Sweden)

    Fader Amanda

    2011-01-01

    Full Text Available Review Objective: To review the recent developments and published literature on laparoendoscopic single-site (LESS surgery in gynaecology. Recent Findings: Minimally invasive surgery has become a standard of care for the treatment of many benign and malignant gynaecological conditions. Recent advances in conventional laparoscopy and robotic-assisted surgery have favorably impacted the entire spectrum of gynaecological surgery. With the goal of improving morbidity and cosmesis, continued efforts towards refinement of laparoscopic techniques have lead to minimization of size and number of ports required for these procedures. LESS surgery is a recently proposed surgical term used to describe various techniques that aim at performing laparoscopic surgery through a single, small-skin incision concealed within the umbilicus. In the last 5 years, there has been a surge in the developments in surgical technology and techniques for LESS surgery, which have resulted in a significant increase in utilisation of LESS across many surgical subspecialties. Recently published outcomes data demonstrate feasibility, safety and reproducibility for LESS in gynaecology. The contemporary LESS literature, extent of gynaecological procedures utilising these techniques and limitations of current technology will be reviewed in this manuscript. Conclusions: LESS surgery represents the newest frontier in minimally invasive surgery. Comparative data and prospective trials are necessary in order to determine the clinical impact of LESS in treatment of gynaecological conditions.

  6. Induction of prophage lambda by chlorinated organics: Detection of some single-species/single-site carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    DeMarini, D.M.; Brooks, H.G. (Environmental Protection Agency, Research Triangle Park, NC (United States))

    1992-01-01

    Twenty-eight chlorinated organic compounds were evaluated for their ability to induce DNA damage using the Microscreen prophage-induction assay in Escherichia coli. Comparison of the performance characteristics of the prophage-induction and Salmonella assays to rodent carcinogenicity assays showed that the prophage-induction assay had a somewhat higher specificity than did the Salmonella assay (70% vs. 50%); sensitivity, concordance, and positive and negative predictivity were similar for the two microbial assays. The Microscreen prophage-induction assay failed to detect eight carcinogens, perhaps due to toxicity or other unknown factors; five of these eight carcinogens were detected by the Salmonella assay. However, the prophage-induction assay did detect six carcinogens that were not detected by the Salmonella assay, and five of these were single-species, single-site carcinogens, mostly mouse liver carcinogens. Some of these carcinogens, such as the chloroethanes, produce free radicals, which may be the basis for their carcinogenicity and ability to induce prophage. The prophage-induction (or other SOS) assay may be useful in identifying some genotoxic chlorinated carcinogens that induce DNA damage that do not revert the standard Salmonella tester strains.

  7. Performance analysis of high frequency single-site-location antenna arrays using numerical electromagnetic modeling

    Science.gov (United States)

    Schiantarelli, Harry T.

    1990-09-01

    Electronic support measures (ESM) systems play an increasingly important role in modern warfare and can influence the outcome of a military engagement. The application of ESM can be extended to anti-guerrilla and anti-drug operations where law enforcement agencies can exploit the fact that their presence is inducing the outlaw to depend more on radio communications to coordinate their activities. When a propagation path of no more than one reflection at the ionosphere (1-hop) can be assumed, position of an HF emitter can be determined by a single observing site using vertical triangulation, provided that the height of the ionosphere at the point where the radio wave is reflected, can be determined. This technique is known as high frequency direction finding single-site-location (HFDF SSL). This thesis analyzes the HFDF SSL error in measuring the direction of arrival of the signal, how this error is generated by the antenna array and its effect on emitter location. The characteristics of the two antenna arrays used by a specific HFDF SSL system that implements the phase-interferometer techniques were studied using electromagnetic modeling.

  8. Single-site Green function of the Dirac equation for full-potential electron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kordt, Pascal

    2012-05-30

    I present an elaborated analytical examination of the Green function of an electron scattered at a single-site potential, for both the Schroedinger and the Dirac equation, followed by an efficient numerical solution, in both cases for potentials of arbitrary shape without an atomic sphere approximation. A numerically stable way to calculate the corresponding regular and irregular wave functions and the Green function is via the angular Lippmann-Schwinger integral equations. These are solved based on an expansion in Chebyshev polynomials and their recursion relations, allowing to rewrite the Lippmann-Schwinger equations into a system of algebraic linear equations. Gonzales et al. developed this method for the Schroedinger equation, where it gives a much higher accuracy compared to previous perturbation methods, with only modest increase in computational effort. In order to apply it to the Dirac equation, I developed relativistic Lippmann-Schwinger equations, based on a decomposition of the potential matrix into spin spherical harmonics, exploiting certain properties of this matrix. The resulting method was embedded into a Korringa-Kohn-Rostoker code for density functional calculations. As an example, the method is applied by calculating phase shifts and the Mott scattering of a tungsten impurity. (orig.)

  9. Hanford Site Welding Program Successfully Providing A Single Site Function For Use By Multiple Contractors

    International Nuclear Information System (INIS)

    Cannell, G.R.

    2009-01-01

    The Department of Energy, Richland Operations (DOE-RL) recently restructured its Hanford work scope, awarding two new contracts over the past several months for a total of three contracts to manage the sites cleanup efforts. DOE-RL met with key contractor personnel prior to and during contract transition to ensure site welding activities had appropriate oversight and maintained code compliance. The transition also provided an opportunity to establish a single site-wide function that would provide welding and materials engineering services to the Hanford site contractors: CH2M HILL Plateau Remediation Company (CHPRC); Mission Support Alliance (MSA); Washington River Protection Solutions (WRPS); and Washington Closure Hanford (WCH). Over the years, multiple and separate welding programs (amongst the several contractors) existed at the Hanford site leading to inefficiencies resulting from duplication of administrative efforts, maintenance of welding procedures, welder performance certifications, etc. The new, single program eliminates these inefficiencies. The new program, co-managed by two of the sites' new contractors, the CHPRC ('owner' of the program and responsible for construction welding services) and the MSA (provides maintenance welding services), provides more than just the traditional construction and maintenance welding services. Also provided, are welding engineering, specialty welding development/qualification for the closure of radioactive materials containers and materials evaluation/failure analysis. The following describes the new Hanford site welding program.

  10. Defining the learning curve of laparoendoscopic single-site Heller myotomy.

    Science.gov (United States)

    Ross, Sharona B; Luberice, Kenneth; Kurian, Tony J; Paul, Harold; Rosemurgy, Alexander S

    2013-08-01

    Initial outcomes suggest laparoendoscopic single-site (LESS) Heller myotomy with anterior fundoplication provides safe, efficacious, and cosmetically superior outcomes relative to conventional laparoscopy. This study was undertaken to define the learning curve of LESS Heller myotomy with anterior fundoplication. One hundred patients underwent LESS Heller myotomy with anterior fundoplication. Symptom frequency and severity were scored using a Likert scale (0 = never/not bothersome to 10 = always/very bothersome). Symptom resolution, additional trocars, and complications were compared among patient quartiles. Median data are presented. Preoperative frequency/severity scores were: dysphagia = 10/8 and regurgitation = 8/7. Additional trocars were placed in 12 patients (10%), of whom all were in the first two quartiles. Esophagotomy/gastrotomy occurred in three patients. Postoperative complications occurred in 9 per cent. No conversions to "open" operations occurred. Length of stay was 1 day. Postoperative frequency/severity scores were: dysphagia = 2/0 and regurgitation = 0/0; scores were less than before myotomy (P learning curve of LESS Heller myotomy with anterior fundoplication is short and safe, because proficiency is quickly attained.

  11. Advanced Aqueous Phase Catalyst Development using Combinatorial Methods, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Combinatorial methods are proposed to develop advanced Aqueous Oxidation Catalysts (AOCs) with the capability to mineralize organic contaminants present in effluents...

  12. Highly dispersed metal catalyst

    Science.gov (United States)

    Xiao, Xin; West, William L.; Rhodes, William D.

    2016-11-08

    A supported catalyst having an atomic level single atom structure is provided such that substantially all the catalyst is available for catalytic function. A process of forming a single atom catalyst unto a porous catalyst support is also provided.

  13. Gossiping Capabilities

    DEFF Research Database (Denmark)

    Mogensen, Martin; Frey, Davide; Guerraoui, Rachid

    declare a high capability in order to augment their perceived quality without contributing accordingly. We evaluate HEAP in the context of a video streaming application on a 236 PlanetLab nodes testbed. Our results shows that HEAP improves the quality of the streaming by 25% over a standard gossip......Gossip-based protocols are now acknowledged as a sound basis to implement collaborative high-bandwidth content dissemination: content location is disseminated through gossip, the actual contents being subsequently pulled. In this paper, we present HEAP, HEterogeneity Aware gossip Protocol, where...... nodes dynamically adjust their contribution to gossip dissemination according to their capabilities. Using a continuous, itself gossip-based, approximation of relative capabilities, HEAP dynamically leverages the most capable nodes by (a) increasing their fanouts (while decreasing by the same proportion...

  14. Predictive design of engineered multifunctional solid catalysts.

    Science.gov (United States)

    Raja, Robert; Potter, Matthew E; Newland, Stephanie H

    2014-06-07

    The ability to devise and design multifunctional active sites at the nanoscale, by drawing on the intricate ability of enzymes to evolve single-sites with distinctive catalytic function, has prompted complimentary and concordant developments in the field of catalyst design and in situ operando spectroscopy. Innovations in design-application approach have led to a more fundamental understanding of the nature of the active site and its mechanistic influence at a molecular level, that have enabled robust structure-property correlations to be established, which has facilitated the dextrous manipulation and predictive design of redox and solid-acid sites for industrially-significant, sustainable catalytic transformations.

  15. Bimetal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K. Y. Simon; Salley, Steve O.; Wang, Huali

    2017-10-03

    A catalyst comprises a carbide or nitride of a metal and a promoter element. The metal is selected from the group consisting of Mo, W, Co, Fe, Rh or Mn, and the promoter element is selected from the group consisting of Ni, Co, Al, Si, S or P, provided that the metal and the promoter element are different. The catalyst also comprises a mesoporous support having a surface area of at least about 170 m.sup.2 g.sup.-1, wherein the carbide or nitride of the metal and the promoter element is supported by the mesoporous support, and is in a non-sulfided form and in an amorphous form.

  16. Catalyst Architecture

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  17. An overview on the applications of 'Doyle catalysts' in asymmetric ...

    Indian Academy of Sciences (India)

    Administrator

    Johnson Matthey has recently obtained a worldwide exclusive licence to manufacture and sell a unique class of chiral dirhodium(II) carboxamidate catalysts called 'Doyle catalysts'. These homogeneous catalysts are capable of producing chiral cyclopropanes, cyclopropenes and C–H insertion products of very high ...

  18. 40 CFR 90.329 - Catalyst thermal stress test.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress test. 90.329... Equipment Provisions § 90.329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for thermally stressing the test catalyst must be capable of maintaining a temperature of 500 ±5 °C and 1000 ±10...

  19. 40 CFR 91.329 - Catalyst thermal stress test.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress test. 91.329....329 Catalyst thermal stress test. (a) Oven characteristics. The oven used for termally stressing the test catalyst must be capable of maintaining a temperature of 500 ±5 °C and 1000 ±10 °C. (b) Evaluation...

  20. Single-site robotic cholecystectomy and robotics training: should we start in the junior years?

    Science.gov (United States)

    Ayabe, Reed I; Parrish, Aaron B; Dauphine, Christine E; Hari, Danielle M; Ozao-Choy, Junko J

    2018-04-01

    It has become increasingly important to expose surgical residents to robotic surgery as its applications continue to expand. Single-site robotic cholecystectomy (SSRC) is an excellent introductory case to robotics. Resident involvement in SSRC is known to be feasible. Here, we sought to determine whether it is safe to introduce SSRC to junior residents. A total of 98 SSRC cases were performed by general surgery residents between August 2015 and August 2016. Cases were divided into groups based on resident level: second- and third-years (juniors) versus fourth- and fifth-years (seniors). Patient age, gender, race, body mass index, and comorbidities were recorded. The number of prior laparoscopic cholecystectomies completed by participating residents was noted. Outcomes including operative time, console time, rate of conversion to open cholecystectomy, and complication rate were compared between groups. Juniors performed 54 SSRC cases, whereas seniors performed 44. There were no significant differences in patient age, gender, race, body mass index, or comorbidities between the two groups. Juniors had less experience with laparoscopic cholecystectomy. There was no significant difference in mean operative time (92.7 min versus 98.0 min, P = 0.254), console time (48.7 min versus 50.8 min, P = 0.639), or complication rate (3.7% versus 2.3%, P = 0.68) between juniors and seniors. SSRC is an excellent way to introduce general surgery residents to robotics. This study shows that with attending supervision, SSRC is feasible and safe for both junior and senior residents with very low complication rates and no adverse effect on operative time. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Port site infiltration of local anesthetic after laparoendoscopic single site surgery for benign adnexal disease.

    Science.gov (United States)

    Kim, Jung Eun; Shim, Seung-Hyuk; Dong, Meari; Lee, Hyojin; Hwang, Han Sung; Kwon, Han Sung; Lee, Sun Joo; Lee, Ji Young; Sohn, In Sook; Kim, Soo-Nyung; Kang, Soon-Beom

    2017-09-01

    To determine whether local bupivacaine injection into the incision site after gynecologic laparoendoscopic single site surgery (LESS) improves postoperative pain. This prospective cohort study included consecutive 158 patients who had LESS for benign adnexal disease from March 2013 to December 2015. Chronologically, 82 patients (March 2013 to August 2014) received no bupivacaine (group 1) and 76 (August 2014 to December 2015) received a bupivacaine block (group 2). For group 2, 10 mL 0.25% bupivacaine was injected into the 20 mm-incision site through all preperitoneal layers after LESS completion. Primary outcome is postoperative pain score using the visual analog scale (VAS). There was no difference in clinicopathological characteristics between the groups. Operating time (expressed as median [range], 92 [55-222] vs. 100 [50-185] minutes, P =0.137) and estimated blood loss (50 [30-1,500] vs. 125 [30-1,000] mL, P =0.482) were similar between the groups. Post-surgical VAS pain scores after 3 hours (3.5 [2-6] vs. 3.5 [2-5], P =0.478), 6 to 8 hours (3.5 [2-6] vs. 3 [1-8], P =0.478), and 16 to 24 hours (3 [2-4] vs. 3 [1-7], P =0.664) did not differ between groups. Bupivacaine injection into the trocar site did not improve postoperative pain after LESS. Randomized trials are needed to evaluate the benefits of local bupivacaine anesthetic for postoperative pain reduction.

  2. Laparo-endoscopic single-site (LESS) cholecystectomy with epidural vs. general anesthesia.

    Science.gov (United States)

    Ross, Sharona B; Mangar, Devanand; Karlnoski, Rachel; Camporesi, Enrico; Downes, Katheryne; Luberice, Kenneth; Haines, Krista; Rosemurgy, Alexander S

    2013-05-01

    Laparo-endoscopic single-site (LESS) surgery involves a single umbilical incision, lending itself to epidural anesthesia. This prospective, randomized study was undertaken to evaluate epidural anesthesia for patients undergoing LESS cholecystectomy, to assess the feasibility, and to analyze all intraoperative and postoperative complications. The secondary objectives were to determine differences in postoperative pain and time until PACU discharge-to-home readiness between patients. With institutional review board approval, 20 patients with chronic cholecystitis, cholelithiasis, and/or biliary dyskinesia were randomized to receive spinal epidural anesthesia (n = 10) or general anesthesia (n = 10). Postoperative pain at rest was recorded in the PACU every 10 min, and at rest and walking at discharge using the visual analog scale (VAS). Operative time and time until PACU discharge-to-home readiness were recorded. Results are expressed as mean ± SD. Patient age, American Society of Anesthesiologists class, and body mass index were similar. There were no additional ports/incisions, conversions to "open" operations, or conversions to general anesthesia. There were no differences in operative duration. Time until postanesthesia care unit discharge-to-home ready was not significantly different. The most common postoperative adverse event was urinary retention (1 epidural and 3 general anesthesia patients). Resting postoperative VAS pain score at discharge was 4.7 ± 2.5 vs. 2.2 ± 1.6 (p = 0.02, general versus epidural anesthesia respectively); the stressed VAS pain score at discharge was 6.1 ± 2.3 vs. 3.1 ± 2.8 (p = 0.02, general versus epidural anesthesia respectively). LESS cholecystectomy with epidural anesthesia was completed with no operative or anesthetic conversions, and less postoperative pain at discharge. Epidural anesthesia appears to be a preferable alternative to general anesthesia for patients undergoing LESS cholecystectomy.

  3. Comparative study of hybrid laparoendoscopic single-site (LESS) partial nephrectomy and conventional multiport laparoscopy.

    Science.gov (United States)

    Redondo, C; Esquinas, C; Meilán, E; García-Tello, A; Arance, I; Angulo, J C

    2017-05-01

    To investigate the surgical and oncological outcomes of hybrid laparoendoscopic single-site (LESS) in partial nephrectomy with reusable components compared with multiport laparoscopy. Hybrid LESS technique with auxiliary 3.5mm trocar (n=20) was compared with conventional multiport laparoscopy (n=26) by a prospective, paired, nonrandomized, and comparative study in partially nephrectomized patients. Follow-up average was 31±18.6 months. In one case, LESS was converted to laparoscopy. No differences were found regarding age, sex, body mass index, laterality, localization, tumor size or use of double J stent. Dominance of Loop-I (P=0.09) and benign histology (P=0.05) were observed in the LESS group. Neither there were differences regarding operating time, ischemia time, use of hemostatic materials, estimated blood loss, postoperative hemoglobin levels, transfusion or other complications. In any case, to extend the skin incision for specimen extraction was not necessary. Drainage time (P=0.006) and hospital stay (P=0.003) were better in LESS patients. Concerning complications, no significant differences were observed according Clavien-Dindo scale. In laparoscopic group one patient died of pulmonary embolism after hospital discharge. No positive margins were observed in any case. During follow-up neither tumor recurrence nor disease progression were observed. Regarding surgical outcomes, partial nephrectomy by LESS technique does not imply improvements, excepting shorter hospital stay, probably due to accurate surgical hemostasis and/or selection of cases. No surgical and oncological risks are involved, as well as no improvement in ischemia time, blood loss or transfusion rate. We find no significant difference in cosmetic outcomes. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. Catalysts for improved fuel processing

    Energy Technology Data Exchange (ETDEWEB)

    Borup, R.L.; Inbody, M.A. [and others

    2000-09-01

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

  5. Coal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kroenig, W.

    1944-02-11

    Some considerations in the selection of a catalyst for the liquid phase of coal hydrogenation are discussed. Some of the previous history of such selections is mentioned. At one stage of the development, the principal catalyst had been iron sulfate (FeSO/sub 4/.7H/sub 2/O). Later, for reasons of cost and availability of large supplies, selections had turned to mixtures of iron sulfate and one or another of some iron oxide- and aluminum oxide-containing byproducts of aluminum manufacture, namely Bayermasse, Luxamsse, or Lautamasse. Much of the discussion centered on optimal proportions for such mixtures, particularly as related to pH values of resulting coal pastes. Upper Silesian coal was more alkaline than Ruhr coal, and Bayermasse, etc., were quite alkaline. Thus, since the iron sulfate served as a partial neutralizer for the coal as well as a catalyst, it seemed necessary to increase the proportions of iron sulfate in the catalyst mixture when processing coal of greater alkalinity. A further reason for a greater proportion of iron sulfate seemed to be that most of the catalytic activity of the iron came from the ferrous iron of iron sulfate rather than from the ferric iron of the other materials. Ferrous-ferric ratios also seemed to indicate that Luxmasse or Lautamasse might be better catalyst components than Bayermasse but their water content sometimes caused handling problems, so Bayermasse had been more widely used. Formation of deposits in the preheater was more likely due to the Bayermasse than to the iron sulfate; sodium sulfide could help to prevent them.

  6. Transition metal complexes supported on metal-organic frameworks for heterogeneous catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Farha, Omar K.; Hupp, Joseph T.; Delferro, Massimiliano; Klet, Rachel C.

    2017-02-07

    A robust mesoporous metal-organic framework comprising a hafnium-based metal-organic framework and a single-site zirconium-benzyl species is provided. The hafnium, zirconium-benzyl metal-organic framework is useful as a catalyst for the polymerization of an alkene.

  7. Capability approach

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal; Kjeldsen, Christian Christrup

    Lærebogen er den første samlede danske præsentation af den af Amartya Sen og Martha Nussbaum udviklede Capability Approach. Bogen indeholder en præsentation og diskussion af Sen og Nussbaums teoretiske platform. I bogen indgår eksempler fra såvel uddannelse/uddannelsespolitik, pædagogik og omsorg....

  8. Ex-vivo training model for laparoendoscopic single-site surgery

    Directory of Open Access Journals (Sweden)

    Kommu Sashi

    2011-01-01

    Full Text Available Background: Laparoendoscopic single-site surgery (LESS has recently been applied successfully in the performance of a host of surgical procedures. Preliminary consensus from the experts is that this mode of surgery is technically challenging and requires expertise. The transition from trainee to practicing surgeon, especially in complex procedures with challenging learning curves, takes time and mentor-guided nurturing. However, the trainee needs to use platforms of training to gain the skills that are deemed necessary for undertaking the live human case. Objective: This article aims to demonstrate a step-by-step means of how to acquire the necessary instrumentation and build a training model for practicing steeplechase exercises in LESS for urological surgeons and trainees. The tool built as a result of this could set the platform for performance of basic and advanced skills uptake using conventional, bent and articulated instruments. A preliminary construct validity of the platform was conducted. Materials and Methods: A box model was fitted with an R-Port™ and camera. Articulated and conventional instruments were used to demonstrate basic exercises (e.g. glove pattern cutting, loop stacking and suturing and advanced exercises (e.g. pyeloplasty. The validation included medical students (M, final year laparoscopic fellows (F and experienced consultant laparoscopic surgeons (C with at least 50 LESS cases experience in total, were tested on eight basic skill tasks (S including manipulation of the flexible cystoscope (S1, hand eye coordination (S2, cutting with flexible scissors (S3, grasping with flexible needle holders (S4, two-handed maneuvers (S5, object translocation (S6, cross hand suturing with flexible instruments (S7 and conduction of an ex-vivo pyeloplasty. Results: The successful application of the box model was demonstrated by trainee based exercises. The cost of the kit with circulated materials was less than £150 (Pounds Sterling

  9. Catalyst Architecture

    DEFF Research Database (Denmark)

    Catalyst Architecture’ takes its point of departure in a broadened understanding of the role of architecture in relation to developmental problems in large cities. Architectural projects frame particular functions and via their form language, they can provide the user with an aesthetic experience....... The broadened understanding of architecture consists in that an architectural project, by virtue of its placement in the context and of its composition of programs, can have a mediating role in a positive or cultural development of the district in question. In this sense, we talk about architecture as catalyst...... cities on the planet have growing pains and social cohesiveness is under pressure from an increased difference between rich and poor, social segregation, ghettoes, immigration of guest workers and refugees, commercial mass tourism etc. In this context, it is important to ask which role architecture...

  10. Laparoendoscopic Single-Site Surgery (LESS) for Excision of a Seminal Vesicle Cyst Associated with Ipsilateral Renal Agenesis

    OpenAIRE

    Jang, Ki Don; Choi, Kyung Hwa; Yang, Seung Choul; Jang, Won Sik; Jang, Ji Young; Han, Woong Kyu

    2011-01-01

    We report a case of laparoendoscopic single-site surgery (LESS) for a symptomatic left seminal vesicular cyst and ipsilateral renal agenesis. A 49-year-old man presented with a 1-year history of severe irritation upon voiding and intractable, recurrent hematospermia. A computed tomography scan showed a 68×41×38 mm sized left seminal vesicular cyst with ipsilateral renal agenesis. LESS was performed successfully to treat the seminal vesicle cyst. The total operative time was 125 minutes, and b...

  11. An introduction to catalyst

    International Nuclear Information System (INIS)

    Jeon, Hak Je

    1988-11-01

    This book explains basic conception of catalyst such as definition, velocity of chemical reaction and velocity of catalyst reaction, absorption with absorption energy and chemical absorption, pore structure with the role of pore and measurement of pore structure, catalyst activity on solid structure, electrical property on catalyst activity, choice and design of catalyst, catalytic reaction with reaction velocity and chemical equilibrium and reaction velocity model, measurement of reaction velocity and material analysis, catalyst for mixed compound, catalyst for solid acid and catalyst for supported metal.

  12. Catalysts for conversion of syngas to liquid motor fuels

    Science.gov (United States)

    Rabo, Jule A.; Coughlin, Peter K.

    1987-01-01

    Synthesis gas comprising carbon monoxide and hydrogen is converted to C.sub.5.sup.+ hydrocarbons suitable for use as liquid motor fuels by contact with a dual catalyst composition capable of ensuring the production of only relatively minor amounts of heavy products boiling beyond the diesel oil range. The catalyst composition, having desirable stability during continuous production operation, employs a Fischer-Tropsch catalyst, together with a co-catalyst/support component. The latter component is a steam-stabilized zeolite Y catalyst of hydrophobic character, desirably in acid-extracted form.

  13. Process of activation of a palladium catalyst system

    Science.gov (United States)

    Sobolevskiy, Anatoly [Orlando, FL; Rossin, Joseph A [Columbus, OH; Knapke, Michael J [Columbus, OH

    2011-08-02

    Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180.degree. C. at a heating rate of from 1-20.degree./min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.

  14. Numerical solution of the relativistic single-site scattering problem for the Coulomb and the Mathieu potential

    Science.gov (United States)

    Geilhufe, Matthias; Achilles, Steven; Köbis, Markus Arthur; Arnold, Martin; Mertig, Ingrid; Hergert, Wolfram; Ernst, Arthur

    2015-11-01

    For a reliable fully-relativistic Korringa-Kohn-Rostoker Green function method, an accurate solution of the underlying single-site scattering problem is necessary. We present an extensive discussion on numerical solutions of the related differential equations by means of standard methods for a direct solution and by means of integral equations. Our implementation is tested and exemplarily demonstrated for a spherically symmetric treatment of a Coulomb potential and for a Mathieu potential to cover the full-potential implementation. For the Coulomb potential we include an analytic discussion of the asymptotic behaviour of irregular scattering solutions close to the origin (r\\ll 1 ).

  15. Screened Coulomb interactions in metallic alloys. II. Screening beyond the single-site and atomic-sphere approximations

    DEFF Research Database (Denmark)

    Ruban, Andrei; Simak, S.I.; Korzhavyi, P.A.

    2002-01-01

    -electron potential and energy. In the case of a random alloy such interactions can be accounted for only by lifting the atomic-sphere and single-site approximations, in order to include the polarization due to local environment effects. Nevertheless, a simple parametrization of the screened Coulomb interactions......A quantitative description of the configurational part of the total energy of metallic alloys with substantial atomic size difference cannot be achieved in the atomic-sphere approximation: It needs to be corrected at least for the multipole-moment interactions in the Madelung part of the one...

  16. Laparoendoscopic single-site surgery (LESS) for excision of a seminal vesicle cyst associated with ipsilateral renal agenesis.

    Science.gov (United States)

    Jang, Ki Don; Choi, Kyung Hwa; Yang, Seung Choul; Jang, Won Sik; Jang, Ji Young; Han, Woong Kyu

    2011-06-01

    We report a case of laparoendoscopic single-site surgery (LESS) for a symptomatic left seminal vesicular cyst and ipsilateral renal agenesis. A 49-year-old man presented with a 1-year history of severe irritation upon voiding and intractable, recurrent hematospermia. A computed tomography scan showed a 68×41×38 mm sized left seminal vesicular cyst with ipsilateral renal agenesis. LESS was performed successfully to treat the seminal vesicle cyst. The total operative time was 125 minutes, and blood loss was minimal. The patient was discharged from the hospital on the second postoperative day.

  17. Robotic-assisted laparoendoscopic single-site surgery (R-LESS) in urology: an evidence-based analysis.

    Science.gov (United States)

    Barret, E; Sanchez-Salas, R; Ercolani, M; Forgues, A; Rozet, F; Galiano, M; Cathelineau, X

    2011-06-01

    The objective of this manuscript is to provide an evidence-based analysis of the current status and future perspectives of robotic laparoendoscopic single-site surgery (R-LESS). A PubMed search has been performed for all relevant urological literature regarding natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS). All clinical and investigative reports for robotic LESS and NOTES procedures in the urological literature have been considered. A significant number of clinical urological procedures have been successfully completed utilizing R-LESS procedures. The available experience is limited to referral centers, where the case volume is sufficient to help overcome the challenges and learning curve of LESS surgery. The robotic interface remains the best fit for LESS procedures but its mode of use continues to evolve in attempts to improve surgical technique. We stand today at the dawn of R-LESS surgery, but this approach may well become the standard of care in the near future. Further technological development is needed to allow widespread adoption of the technique.

  18. Safety and Efficacy of Single-site Phacotrabeculectomy With Mitomicin C Using Nylon and Polyglactin Suture for Scleral Tunnel Closure.

    Science.gov (United States)

    Vijaya, Lingam; David, Rathini L

    2015-01-01

    To evaluate the efficacy of polyglactin use along with nylon suture in scleral tunnel closure after single-site phacotrabeculectomy. This retrospective case series included 139 eyes of 139 patients who had scleral tunnel closure with 1 polyglactin and 1 nylon suture after single-site phacotrabeculectomy with a low dose of mitomycin C between 2002 and 2005. The intraocular pressure (IOP), the visual acuity, the number of glaucoma medications, postoperative complications, and interventions were the outcomes measured. The majority of them had primary open-angle glaucoma (93 eyes, 67%), 93 eyes (67%) had severe glaucomatous optic neuropathy, and 77 eyes (55.3%) had severe visual-field loss. The IOP decreased from a mean preoperative value of 18.1±5.3 mm Hg on a mean number of 1.8±0.8 glaucoma medications to mean IOPs of 13.3±4.6, 14.0±4.3, and 11.8±3.9 mm Hg on a mean number of 0.2±0.6, 0.3±0.7, 0.5±1.0 glaucoma medications (PNylon suturelysis with laser was performed in 16 eyes (11.5%). The technique used here seems to be effective in controlling the IOP and has very minimal associated complications.

  19. Single-Site Active Cobalt-Based Photocatalyst with a Long Carrier Lifetime for Spontaneous Overall Water Splitting.

    Science.gov (United States)

    Liu, Wei; Cao, Linlin; Cheng, Weiren; Cao, Yuanjie; Liu, Xiaokang; Zhang, Wei; Mou, Xiaoli; Jin, Lili; Zheng, Xusheng; Che, Wei; Liu, Qinghua; Yao, Tao; Wei, Shiqiang

    2017-08-01

    An active and stable photocatalyst to directly split water is desirable for solar-energy conversion. However, it is difficult to accomplish overall water splitting without sacrificial electron donors. Herein, we demonstrate a strategy via constructing a single site to simultaneously promote charge separation and catalytic activity for robust overall water splitting. A single Co 1 -P 4 site confined on g-C 3 N 4 nanosheets was prepared by a facile phosphidation method, and identified by electron microscopy and X-ray absorption spectroscopy. This coordinatively unsaturated Co site can effectively suppress charge recombination and prolong carrier lifetime by about 20 times relative to pristine g-C 3 N 4 , and boost water molecular adsorption and activation for oxygen evolution. This single-site photocatalyst exhibits steady and high water splitting activity with H 2 evolution rate up to 410.3 μmol h -1  g -1 , and quantum efficiency as high as 2.2 % at 500 nm. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Cosmetic outcomes of laparoendoscopic single-site hysterectomy compared with multi-port surgery: randomized controlled trial.

    Science.gov (United States)

    Song, Taejong; Cho, Juhee; Kim, Tae-Joong; Kim, Im-Ryung; Hahm, Tae Soo; Kim, Byoung-Gie; Bae, Duk-Soo

    2013-01-01

    To compare cosmetic satisfaction with laparoendoscopic single-site surgery (LESS) compared with multi-port surgery. Randomized controlled trial (Canadian Task Force classification I). University hospital. Twenty women who underwent laparoscopically-assisted vaginal hysterectomy (LAVH) via LESS or multi-port surgery. Laparoendoscopic single-site surgery or multi-port surgery. Cosmetic satisfaction was assessed using the Body Image Questionnaire at baseline and at 1, 4, and 24 weeks after surgery. Of the 20 LESS procedures, 1 was converted to multi-port surgery because of severe adhesions, and 1 woman assigned to undergo multi-port surgery was lost to follow-up. The 2 surgery groups did not differ in clinical demographic data and surgical results or postoperative pain scores at 12, 24, and 36 hours. Compared with the multi-port group, the LESS group reported significantly higher cosmetic satisfaction at 1, 4, and 24 weeks after surgery (p surgery, LESS is not only a feasible approach with comparable operative outcomes but also has an advantage insofar as cosmetic outcome. Copyright © 2013 AAGL. Published by Elsevier Inc. All rights reserved.

  1. Supported Single-Site Ti(IV) on a Metal–Organic Framework for the Hydroboration of Carbonyl Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhiyuan [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Liu, Dong [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Camacho-Bunquin, Jeffrey [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Zhang, Guanghui [Department; Yang, Dali [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; López-Encarnación, Juan M. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Department; Xu, Yunjie [Department; Ferrandon, Magali S. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Niklas, Jens [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Poluektov, Oleg G. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Jellinek, Julius [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Lei, Aiwen [College; amp, Molecular Sciences, Institute of Advanced Studies, Wuhan University, Wuhan 430072, PR China; Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Bunel, Emilio E. [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Delferro, Massimiliano [Chemical; amp, Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States

    2017-10-10

    ABSTRACT: A stable and structurally well-defined titanium alkoxide catalyst supported on a metal-organic-framework (MOF) of UiO-67 topology (ANL1-Ti(OiPr)2) was synthesized and fully characterized by a variety of analytical and spectroscopic techniques, including BET, TGA, PXRD, XAS, DRIFT, SEM, and DFT computations. The Ti-functionalized MOF was demonstrated active for the catalytic hydroboration of a wide range of aldehydes and ketones with HBpin as the boron source. Compared to traditional homogeneous and supported hydroboration catalysts, ANL1-Ti(OiPr)2 is completely recyclable and reusable, making it a promising hydroboration catalyst alternative for green and sustainable chemical synthesis. DFT calculations suggest that the catalytic hydroboration proceeds via a (1) hydride transfer between the active Ti-hydride species and a carbonyl moiety (rate determining step), and (2) alkoxide transfer (intramolecular σ-bond metathesis) to generate the boronate ester product.

  2. Single site porphyrine-like structures advantages over metals for selective electrochemical CO2 reduction

    DEFF Research Database (Denmark)

    Bagger, Alexander; Ju, Wen; Varela, Ana Sofia

    2017-01-01

    the competing Hydrogen Evolution Reaction (HER). The single metal site in a porphyrine-like structure requires an ontop site binding of hydrogen, compared to the hollow site binding of hydrogen on a metal catalyst surface. The difference in binding site structure gives a fundamental energy-shift in the scaling......Currently, no catalysts are completely selective for the electrochemical CO2 Reduction Reaction (CO2RR). Based on trends in density functional theory calculations of reaction intermediates we find that the single metal site in a porphyrine-like structure has a simple advantage of limiting...

  3. Ruthenium-based olefin metathesis catalysts bearing pH-responsive ligands: External control of catalyst solubility and activity

    Science.gov (United States)

    Balof, Shawna Lynn

    2011-12-01

    Sixteen novel, Ru-based olefin metathesis catalysts bearing pH responsive ligands were synthesized. The pH-responsive groups employed with these catalysts included dimethylamino (NMe2) modified NHC ligands as well as N-donor dimethylaminopyridine (DMAP) and 3-(o-pyridyl)propylidene ligands. These pH-responsive ligands provided the means by which the solubility and/or activity profiles of the catalysts produced could be controlled via acid addition. The main goal of this dissertation was to design catalyst systems capable of performing ring opening metathesis (ROMP) and ring closing metathesis (RCM) reactions in both organic and aqueous media. In an effort to quickly gain access to new catalyst structures, a template synthesis for functionalized NHC ligand precursors was designed, in addition to other strategies, to obtain ligand precursors with ancillary NMe2 groups. Kinetic studies for the catalysts produced from these precursors showed external control of catalyst solubility was afforded via protonation of the NMe2 groups of their NHC ligands. Additionally, this protonation afforded external control of catalyst propagation rates for several catalysts. This is the first known independent external control for the propagation rates of ROMP catalysts. The incorporation of pH-responsive N-donor ligands into catalyst structures also provided the means for the external control of metathesis activity, as the protonation of these ligands resulted in an increased initiation rate based on their fast and irreversible dissociation from the metal center. The enhanced external control makes these catalysts applicable to a wide range of applications, some of which have been explored by us and/or through collaboration. Three of the catalysts designed showed remarkable metathesis activity in aqueous media. These catalysts displayed comparable RCM activity in aqueous media to a class of water-soluble catalysts reported by Grubbs et al., considered to be the most active catalyst for

  4. Ovarian Suspension With Adjustable Sutures: An Easy and Helpful Technique for Facilitating Laparoendoscopic Single-Site Gynecologic Surgery.

    Science.gov (United States)

    Chen, Kuo-Hu; Chen, Li-Ru; Seow, Kok-Min

    2015-01-01

    To describe a method of ovarian suspension with adjustable sutures (OSAS) for facilitating laparoendoscopic single-site gynecologic surgery (LESS) and to investigate the effect of OSAS on LESS. Prospective cohort study (Canadian Task Force classification: II-2). University teaching hospital. One hundred seventy-eight patients with benign 5- to 15-cm cystic ovarian tumors who underwent LESS with OSAS (suspension group, n = 90) and without OSAS (control group, n = 88). For patients who underwent OSAS (suspension group), 1 end of double-head straight needles with a polypropylene suture was inserted into the pelvic cavity through the abdominal skin to penetrate the cyst or ovarian parenchyma and puncture outside the abdominal skin. After cutting off the needles, both sides of the remaining suture were held together by a clamp, without knotting, so that the manipulator could "lift," "loosen," or "fix" the stitches to adjust the tension. The average time to create OSAS was 2.9 min. For the suspension and control groups, the average blood loss was 81.4 and 131.8 mL (p < .001), and the operative time was 42.0 and 61.3 min (p < .001), respectively. There were no significant differences in the incidence of complications (5.6% vs 9.1%; p = .365), but there were significant differences in conversions to standard non-single-site laparoscopy (5.6% vs 15.9%; p = .025) and laparotomy (1.1% vs 6.8%; p = .040). Logistic regression analysis revealed that the ratios of conversion to standard non-single-site laparoscopy (odds ratio [OR], 0.126; 95% confidence interval [CI], 0.311-0.508) and laparotomy (OR, 0.032; 95% CI, 0.002-0.479) were much lower in the suspension group; the risk of complications was comparable (OR, 0.346; 95% CI, 0.085-1.403). OSAS is an easy, safe, and feasible method that offers advantages during LESS. Although routine use of OSAS is not necessary, OSAS can be considered during LESS to facilitate the surgery. Copyright © 2015 AAGL. Published by Elsevier Inc. All

  5. Wegner estimate and localization for alloy-type models with sign-changing exponentially decaying single-site potentials

    Science.gov (United States)

    Leonhardt, Karsten; Peyerimhoff, Norbert; Tautenhahn, Martin; Veselić, Ivan

    2015-05-01

    We study Schrödinger operators on L2(ℝd) and ℓ2(ℤd) with a random potential of alloy-type. The single-site potential is assumed to be exponentially decaying but not necessarily of fixed sign. In the continuum setting, we require a generalized step-function shape. Wegner estimates are bounds on the average number of eigenvalues in an energy interval of finite box restrictions of these types of operators. In the described situation, a Wegner estimate, which is polynomial in the volume of the box and linear in the size of the energy interval, holds. We apply the established Wegner estimate as an ingredient for a localization proof via multiscale analysis.

  6. Current status and future perspectives in laparoendoscopic single-site and natural orifice transluminal endoscopic urological surgery.

    Science.gov (United States)

    Autorino, Riccardo; Stein, Robert J; Lima, Estevão; Damiano, Rocco; Khanna, Rakesh; Haber, Georges-Pascal; White, Michael A; Kaouk, Jihad H

    2010-05-01

    Objective of this study is to provide an evidence-based analysis of the current status and future perspectives of scarless urological surgery. A PubMed search has been performed for all relevant urological literature regarding natural orifice transluminal endoscopic surgery (NOTES) and laparoendoscopic single-site surgery (LESS). In addition, experience with LESS and NOTES at our own institution has been considered. All clinical and investigative reports for LESS and NOTES procedures in the urological literature have been considered. A wide variety of clinical procedures in urology have been successfully completed by using LESS techniques. Thus far, experience with NOTES has largely been investigational, although early clinical reports are emerging. Further development of instrumentation and platforms is necessary for both techniques to become more widely adopted throughout the urological community.

  7. The use of expanding ports in laparo-endoscopic single-site surgery may cause more pain

    DEFF Research Database (Denmark)

    Dressler, Jannie; Jorgensen, Lars N

    2017-01-01

    BACKGROUND: Previous meta-analyses on the clinical outcome after laparo-endoscopic single-site surgery (LESS) versus conventional laparoscopic surgery (CLS) have not revealed any major differences in postoperative pain between the two procedures. This meta-analysis aims to evaluate the difference...... for randomized clinical trials (RCTs) on LESS versus CLS for general abdominal procedures. Weighted mean difference (WMD) and Odds ratios (OR) were calculated with 95% confidence intervals (CI). RESULTS: A total of 29 RCTs with 2999 procedures were included. Pain (VAS 0-10) 6 h after surgery was significantly...... in LESSex procedures compared to CLS, OR = 1.94 (1.03-3.63). CONCLUSION: The present meta-analysis indirectly indicates that the type of access device that is used for an abdominal LESS procedure may contribute to the development of early postoperative pain as the use of a non-expanding model was associated...

  8. Heterogeneous Metal Catalysts for Oxidation Reactions

    Directory of Open Access Journals (Sweden)

    Md. Eaqub Ali

    2014-01-01

    Full Text Available Oxidation reactions may be considered as the heart of chemical synthesis. However, the indiscriminate uses of harsh and corrosive chemicals in this endeavor are threating to the ecosystems, public health, and terrestrial, aquatic, and aerial flora and fauna. Heterogeneous catalysts with various supports are brought to the spotlight because of their excellent capabilities to accelerate the rate of chemical reactions with low cost. They also minimize the use of chemicals in industries and thus are friendly and green to the environment. However, heterogeneous oxidation catalysis are not comprehensively presented in literature. In this short review, we clearly depicted the current state of catalytic oxidation reactions in chemical industries with specific emphasis on heterogeneous catalysts. We outlined here both the synthesis and applications of important oxidation catalysts. We believe it would serve as a reference guide for the selection of oxidation catalysts for both industries and academics.

  9. Attractive Noncovalent Interactions in the Mechanism of Grubbs Second-Generation Ru Catalysts for Olefin Metathesis.

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan; Truhlar, Donald G.

    2007-05-10

    Second-generation ruthenium carbenoid catalysts for olefin metathesis are a hundred to a thousand times more active than first-generation catalysts, despite a slower initiation step. A new density functional capable of treating medium-range correlation energy shows that the relative rates of generation of the catalyst are determined by attractive noncovalent interactions.

  10. Amorphous molybdenum sulfides as hydrogen evolution catalysts.

    Science.gov (United States)

    Morales-Guio, Carlos G; Hu, Xile

    2014-08-19

    Providing energy for a population projected to reach 9 billion people within the middle of this century is one of the most pressing societal issues. Burning fossil fuels at a rate and scale that satisfy our near-term demand will irreversibly damage the living environment. Among the various sources of alternative and CO2-emission-free energies, the sun is the only source that is capable of providing enough energy for the whole world. Sunlight energy, however, is intermittent and requires an efficient storage mechanism. Sunlight-driven water splitting to make hydrogen is widely considered as one of the most attractive methods for solar energy storage. Water splitting needs a hydrogen evolution catalyst to accelerate the rate of hydrogen production and to lower the energy loss in this process. Precious metals such as Pt are superior catalysts, but they are too expensive and scarce for large-scale applications. In this Account, we summarize our recent research on the preparation, characterization, and application of amorphous molybdenum sulfide catalysts for the hydrogen evolution reaction. The catalysts can be synthesized by electrochemical deposition under ambient conditions from readily available and inexpensive precursors. The catalytic activity is among the highest for nonprecious catalysts. For example, at a loading of 0.2 mg/cm(2), the optimal catalyst delivers a current density of 10 mA/cm(2) at an overpotential of 160 mV. The growth mechanism of the electrochemically deposited film catalysts was revealed by an electrochemical quartz microcrystal balance study. While different electrochemical deposition methods produce films with different initial compositions, the active catalysts are the same and are identified as a "MoS(2+x)" species. The activity of the film catalysts can be further promoted by divalent Fe, Co, and Ni ions, and the origins of the promotional effects have been probed. Highly active amorphous molybdenum sulfide particles can also be prepared

  11. Activation of molecular catalysts using semiconductor quantum dots

    Science.gov (United States)

    Meyer, Thomas J [Chapel Hill, NC; Sykora, Milan [Los Alamos, NM; Klimov, Victor I [Los Alamos, NM

    2011-10-04

    Photocatalytic materials based on coupling of semiconductor nanocrystalline quantum dots (NQD) and molecular catalysts. These materials have capability to drive or catalyze non-spontaneous chemical reactions in the presence of visible radiation, ultraviolet radiation, or both. The NQD functions in these materials as a light absorber and charge generator. Following light absorption, the NQD activates a molecular catalyst adsorbed on the surface of the NQD via transfer of one or more charges (either electrons or electron-holes) from the NQD to the molecular catalyst. The activated molecular catalyst can then drive a chemical reaction. A photoelectrolytic device that includes such photocatalytic materials is also described.

  12. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    The title of my PhD thesis is “Design of Heterogeneous Catalysts”. Three reactions have been investigated: the methanation reaction, the Fischer-Tropsch reaction, and the NH3-based selective catalytic reduction (SCR) of NO. The experimental work performed in connection with the methanation reaction...... hydrogenation. For both systems a maximum in catalytic activity was found for some of the bimetallic catalysts being superior to the monometallic catalysts. This resulted in volcano curves for all investigated systems. In the Fischer-Tropsch reaction promotion of cobalt catalysts with manganese was studied...... 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...

  13. Patterns and plasticity in RNA-protein interactions enable recruitment of multiple proteins through a single site

    Science.gov (United States)

    Valley, Cary T.; Porter, Douglas F.; Qiu, Chen; Campbell, Zachary T.; Hall, Traci M. Tanaka; Wickens, Marvin

    2012-01-01

    mRNA control hinges on the specificity and affinity of proteins for their RNA binding sites. Regulatory proteins must bind their own sites and reject even closely related noncognate sites. In the PUF [Pumilio and fem-3 binding factor (FBF)] family of RNA binding proteins, individual proteins discriminate differences in the length and sequence of binding sites, allowing each PUF to bind a distinct battery of mRNAs. Here, we show that despite these differences, the pattern of RNA interactions is conserved among PUF proteins: the two ends of the PUF protein make critical contacts with the two ends of the RNA sites. Despite this conserved “two-handed” pattern of recognition, the RNA sequence is flexible. Among the binding sites of yeast Puf4p, RNA sequence dictates the pattern in which RNA bases are flipped away from the binding surface of the protein. Small differences in RNA sequence allow new modes of control, recruiting Puf5p in addition to Puf4p to a single site. This embedded information adds a new layer of biological meaning to the connections between RNA targets and PUF proteins. PMID:22467831

  14. The role of benzodiazepines in breathlessness: a single site, open label pilot of sustained release morphine together with clonazepam.

    Science.gov (United States)

    Allcroft, Peter; Margitanovic, Vera; Greene, Aine; Agar, Meera R; Clark, Katherine; Abernethy, Amy P; Currow, David C

    2013-07-01

    Breathlessness at rest or on minimal exertion despite optimal treatment of underlying cause(s) is distressing and prevalent. Opioids can reduce the intensity of chronic refractory breathlessness and an anxiolytic may be of benefit. This pilot aimed to determine the safety and feasibility of conducting a phase III study on the intensity of breathlessness by adding regular benzodiazepine to low-dose opioid. This is a single site, open label phase II study of the addition of regular clonazepam 0.5 mg nocte orally to Kapanol(R) 10 mg (sustained release morphine sulphate) orally mane together with docusate/sennosides in people with modified Medical Research Council Scale ≥2. Breathlessness intensity on day four was the efficacy outcome. Participants could extend for another 10 days if they achieved >15% reduction over their own baseline breathlessness intensity. Eleven people had trial medication (eight males, median age 78 years (68 to 89); all had COPD; median Karnofsky 70 (50 to 80); six were on long-term home oxygen. Ten people completed day four. One person withdrew because of unsteadiness on day four. Five participants reached the 15% reduction, but only three went on to the extension study, all completing without toxicity. This study was safe, feasible and there appears to be a group who derive benefits comparable to titrated opioids. Given the widespread use of benzodiazepines for the symptomatic treatment of chronic refractory breathlessness and its poor evidence base, there is justification for a definitive phase III study.

  15. The effectiveness of laparoendoscopic single-site surgery (LESS) compared with conventional laparoscopic surgery for ectopic pregnancy with hemoperitoneum.

    Science.gov (United States)

    Yang, Juseok; Na, Yong Jin; Song, Yong Jung; Choi, Ook Hwan; Lee, Sun Kyung; Kim, Hwi Gon

    2016-02-01

    The purpose of this study was to compare clinical outcomes of conventional laparoscopic surgery and laparoendoscopic single-site surgery (LESS) in the surgical treatment of tubal ectopic pregnancy. A total of 156 patients were diagnosed with ectopic pregnancies by ultrasonography and serum β-human chorionic gonadotrophin (β-hCG) levels at Pusan National University Yangsan Hospital from January 2009 through December 2013. We excluded 28 patients who only received medical treatment, 15 patients who underwent surgery by laparotomy for severe hypovolemic shock, and 30 patients who presented with less than 1 L of hemoperitoneum. Of the 83 patients with massive hemoperitoneum, 38 patients had LESS performed while the remaining 45 patients underwent conventional laparoscopic surgery. In this study, there were no statistically significant differences in clinical outcomes in either surgical method except for operative time. Operative time of LESS was significantly shorter than conventional surgery for patients with more than 500 mL of hemoperitoneum. LESS is a safe and feasible surgical approach in the treatment of tubal ectopic pregnancy. At the same time, LESS has been shown to be more effective than conventional laparoscopic surgery in handling massive hemoperitoneum of more than 1 L, which is a common complication of ectopic pregnancy. Copyright © 2016. Published by Elsevier B.V.

  16. Comparative study of multiport laparoscopy and umbilical laparoendoscopic single-site surgery with reusable platform for treating renal masses.

    Science.gov (United States)

    Chantada, C; García-Tello, A; Esquinas, C; Moraga, A; Redondo, C; Angulo, J C

    Umbilical laparoendoscopic single-site (LESS) surgery is an increasingly used modality for treating renal masses. We present a prospective comparison between LESS renal surgery and conventional laparoscopy. A comparative paired study was conducted that evaluated the surgical results and complications of patients with renal neoplasia treated with LESS surgery (n=49) or multiport laparoscopy (n=53). The LESS approach was performed with reusable material placed in the navel and double-rotation curved instruments. An additional 3.5-mm port was employed in 69.4% of the cases. We assessed demographic data, the type of technique (nephrectomy, partial nephrectomy and nephroureterectomy), surgical time, blood loss, haemoglobin, need for transfusion, number and severity of complications (Clavien-Dindo), hospital stay, histological data and prognosis. There were no differences in follow-up, age, sex, body mass index, preoperative haemoglobin levels or type of surgery. Conversion occurred in 2 cases (1 in each group). The surgical time was equivalent (P=.6). Intraoperative transfusion (P=.03) and blood loss (Plaparoscopy (P=.0013). Umbilical LESS surgery with reusable platform enables various surgical techniques to be performed when treating renal masses, with time consumption and safety comparable to conventional laparoscopy. The LESS approach is advantageous in terms of blood loss and hospital stay. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  17. Laparoendoscopic Single-site Surgery (LESS) for Prophylactic Salpingo-oophorectomy Improves Cosmetic Satisfaction Compared to Standard Laparoscopy.

    Science.gov (United States)

    Miailhe, Gregoire; Dauchy, Sarah; Bentivegna, Enrica; Gouy, Sebastien; Charles, Cecile; Delaloge, Suzette; Morice, Philippe; Uzan, Catherine

    2015-11-01

    Less invasive prophylactic bilateral salpingo-oophorectomy (PBSO) may diminish the general consequences of surgery for BRCA mutation carriers. The objective of the present study was to compare the psychological impact and satisfaction following minimal-invasive laparoendoscopic single-site surgery (LESS) versus that observed with the standard procedure. This prospective longitudinal study was proposed to all consecutive patients who underwent ambulatory PBSO between January 2012 and January 2014 at our Center. The psychological impact and esthetic satisfaction were prospectively studied. Patients rated their satisfaction using the 4-grade Likert scale. Their emotional state and postoperative pain were explored respectively with validated questionnaires (IES-R, PANAS) and the Verbal Numerical Rating Scale (VNRS). Operative outcomes were also analyzed. Twenty patients underwent LESS PBSO and 10 patients had the standard laparoscopic (SL) PBSO. The mean satisfaction scores were significantly higher in the LESS group one month and six months after surgery. Both groups reported a reduction of intrusive thoughts and negative affects after surgery. Postoperative pain and operative outcomes were similar. A significant improvement of cosmetic satisfaction after LESS compared to SL could help patients accept PBSO. The emotional impact of PBSO is not modified by ambulatory LESS. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  18. Torsion of a Subserosal Myoma Managed by Gasless Laparoendoscopic Single-Site Myomectomy with In-Bag Manual Extraction

    Directory of Open Access Journals (Sweden)

    Akihiro Takeda

    2016-01-01

    Full Text Available Acute torsion of a subserosal myoma is a rare surgical emergency that is infrequently diagnosed preoperatively. Furthermore, laparoendoscopic single-site (LESS myomectomy with in-bag tissue extraction for the management of this disorder has not yet been described. A 43-year-old, gravida 1, para 1 woman was referred to our department due to a solid pelvic mass associated with persistent abdominal pain. A pedunculated subserosal myoma with torsion was strongly suspected based on ultrasonography and magnetic resonance imaging. Emergency LESS surgery showed that the subserosal myoma arising from the posterior uterine wall torted at its pedicle in the cul-de-sac. The twisted myoma node was excised by coagulation and cut using a LigaSure Atlas, followed by in-bag manual morcellation and extraction through an umbilical wound. The present case report emphasizes that LESS myomectomy with in-bag tissue extraction is a feasible minimally invasive surgical option for the management of subserosal myoma with torsion after a precise imaging-based diagnostic evaluation.

  19. Seasonal variation of heavy metals in ambient air and precipitation at a single site in Washington, DC

    International Nuclear Information System (INIS)

    Melaku, Samuel; Morris, Vernon; Raghavan, Dharmaraj; Hosten, Charles

    2008-01-01

    Atmospheric samples of precipitation and ambient air were collected at a single site in Washington, DC, for 7 months (for ambient air samples) and 1 year (for wet deposition samples) and analyzed for arsenic, cadmium, chromium and lead. The ranges of heavy metal concentrations for 6-day wet deposition samples collected over the 1-year period were 0.20-1.3 μg/l, 0.060-5.1 μg/l, 0.062-4.6 μg/l and 0.11-3.2 μg/l for arsenic, cadmium, chromium and lead, respectively, with a precision better than 5% for more than 95% of the measurements. The ranges of heavy metal concentrations for the 6-day ambient air samples were 0.800-15.7 ng/m 3 , 1.50-30.0 ng/m 3 , 16.8-112 ng/m 3 , and 2.90-137 ng/m 3 for arsenic, cadmium, chromium and lead, respectively, with a precision better than 10%. The spread in the heavy metal concentration over the observation period suggests a high seasonal variability for heavy metal content in both ambient air and wet deposition samples. - High seasonal variability of heavy metals were observed in both ambient air and wet deposition samples

  20. Optimal Catalyst and Cocatalyst Precontacting in Industrial Ethylene Copolymerization Processes

    Directory of Open Access Journals (Sweden)

    Paul Aigner

    2016-01-01

    Full Text Available In industrial-scale catalytic olefin copolymerization processes, catalyst and cocatalyst precontacting before being introduced in the polymerization reactor is of profound significance in terms of catalyst kinetics and morphology control. The precontacting process takes place under either well-mixing (e.g., static mixers or plug-flow (e.g., pipes conditions. The scope of this work is to study the influence of mixing on catalyst/cocatalyst precontacting for a heterogeneous Ziegler-Natta catalyst system under different polymerization conditions. Slurry ethylene homopolymerization and ethylene copolymerization experiments with 1-butene are performed in a 0.5 L reactor. In addition, the effect of several key parameters (e.g., precontacting time, and ethylene/hydrogen concentration on catalyst activity is analyzed. Moreover, a comprehensive mass transfer model is employed to provide insight on the mass transfer process and support the experimental findings. The model is capable of assessing the external and internal mass transfer limitations during catalyst/cocatalyst precontacting process. It is shown that catalyst/cocatalyst precontacting is very important for the catalyst activation as well as for the overall catalyst kinetic behavior. The study reveals that there is an optimum precontacting time before and after which the catalyst activity decreases, while this optimum time depends on the precontacting mixing conditions.

  1. Organometallic synthesis, reactivity and catalysis in the solid state using well-defined single-site species

    Science.gov (United States)

    Pike, Sebastian D.; Weller, Andrew S.

    2015-01-01

    Acting as a bridge between the heterogeneous and homogeneous realms, the use of discrete, well-defined, solid-state organometallic complexes for synthesis and catalysis is a remarkably undeveloped field. Here, we present a review of this topic, focusing on describing the key transformations that can be observed at a transition-metal centre, as well as the use of well-defined organometallic complexes in the solid state as catalysts. There is a particular focus upon gas–solid reactivity/catalysis and single-crystal-to-single-crystal transformations. PMID:25666064

  2. Methods of making textured catalysts

    Science.gov (United States)

    Werpy, Todd [West Richland, WA; Frye, Jr., John G.; Wang, Yong [Richland, WA; Zacher, Alan H [Kennewick, WA

    2010-08-17

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

  3. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

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

  4. Rights, goals, and capabilities

    NARCIS (Netherlands)

    van Hees, M.V.B.P.M

    This article analyses the relationship between rights and capabilities in order to get a better grasp of the kind of consequentialism that the capability theory represents. Capability rights have been defined as rights that have a capability as their object (rights to capabilities). Such a

  5. 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....

  6. Single-site robotic cholecystectomy (SSRC) versus single-incision laparoscopic cholecystectomy (SILC): comparison of learning curves. First European experience.

    Science.gov (United States)

    Spinoglio, Giuseppe; Lenti, Luca Matteo; Maglione, Valeria; Lucido, Francesco Saverio; Priora, Fabio; Bianchi, Paolo Pietro; Grosso, Federica; Quarati, Raul

    2012-06-01

    Single-incision laparoscopic surgery is an emerging procedure developed to decrease parietal trauma and improve cosmetic results. However, many technical constraints, such as lack of triangulation, instrument collisions, and cross-handing, hamper this approach. Using a robotic platform may overcome these problems and enable more precise surgical actions by increasing freedom of movement and by restoring intuitive instrument control. We retrospectively collected, under institutional review board approval, data on the first 25 patients who underwent single-site robotic cholecystectomies (SSRC) at our center. Patients enrolled in this study underwent SSRC for symptomatic biliary gallstones or polyposis. Exclusion criteria were: BMI > 33; acute cholecystitis; previous upper abdominal surgery; ASA > II; and age >80 and <18 years. All procedures were performed with the da Vinci Si Surgical System and a dedicated SSRC kit (Intuitive). After discharge, patients were followed for 2 months. These SSRC cases were compared to our first 25 single-incision laparoscopic cholecystectomies (SILC) and with the literature. There were no differences in patient characteristics between groups (gender, P = 0.4404; age, P = 0.7423; BMI, P = 0.5699), and there were no conversions or major complications in either cohort. Operative time was significantly longer for the SILC group compared with SSRC (83.2 vs. 62.7 min, P = 0.0006), and SSRC operative times did not change significantly along the series. The majority of patients in each group were discharged within 24 h, with an average length of hospital stay of 1.2 days for the SILC group and 1.1 days for the SSRC group (P = 0.2854). No wound complications (infection, incisional hernia) were observed in the SSRC group and in the SILC. Our preliminary experience shows that SSRC is safe, can easily be learned, and performed in a reproducible manner and is faster than SILC.

  7. A comparative study of standard versus laparoendoscopic single-site surgery (LESS) totally extraperitoneal (TEP) inguinal hernia repair.

    Science.gov (United States)

    Tai, Huai-Ching; Lin, Chia-Da; Chung, Shiu-Dong; Chueh, Shih-Chieh Jeff; Tsai, Yao-Chou; Yang, Stephen Shei-Dei

    2011-09-01

    Laparoscopic inguinal hernia repair has been around since the 1990s. A novel surgical approach known as laparoendoscopic single-site surgery (LESS) has been developed to reduce the port-related morbidities and improve the cosmetic outcomes of laparoscopic surgery, including totally extraperitoneal (TEP) inguinal hernia repair. The aim of the present study was to evaluate the safety and feasibility of the LESS TEP technique for inguinal hernia repair and compare the outcomes with the standard TEP approach. Between January and May 2009, 54 consecutive healthy patients (48 men and 6 women) underwent LESS TEP inguinal hernia repair at our institute. All procedures were performed using our homemade single port for simultaneous passage of the laparoscope and instruments. The perioperative data, including patient age, sex, body mass index (BMI), hernia characteristics, operative time, complications, length of hospital stay, return to normal activity, pain score, and cosmetic result, were prospectively collected. All LESS TEP procedures were completed successfully without conversion to standard laparoscopic or open surgery. A total of 98 LESS TEP hernia repairs were performed in 54 patients and compared with 152 standard TEP operations. The mean operative time was significantly shorter in the standard TEP series (61.8 ± 26.0 vs. 70.9 ± 23.8 min, p = 0.04). Other perioperative parameters, including the length of hospital stay, time until return to full activity, complication rate, pain score, and cosmetic result, were all comparable between the two techniques. Our short-term experience with LESS TEP inguinal hernia repair has shown that in experienced hands, inguinal hernia repair via the LESS TEP technique is as safe as the standard TEP technique. However, based on our evidence, we currently believe that the LESS TEP technique is not an efficacious surgical alternative to the standard TEP technique for inguinal hernias.

  8. Multi-institutional Experience in Laparoendoscopic Single-site Surgery (LESS): For Major Extirpative and Reconstructive Procedures in Pediatric Urology.

    Science.gov (United States)

    Gor, Ronak A; Long, Christopher J; Shukla, Aseem R; Kirsch, Andrew J; Perez-Brayfield, Marcos; Srinivasan, Arun K

    2016-02-01

    To review peri-procedural outcomes from a large, multi-institutional series of pediatric urology patients treated with laparaendoscopic single-site surgery (LESS) for major extirpative and reconstructive procedures. Consecutive LESS cases between January 2011 and May 2014 from three free-standing pediatric referral centers were reviewed. Data include age, sex, operative time, blood loss, length of stay, and complications according to the modified Clavien-Dindo classification. Hasson technique was used for peritoneal entry, GelPOINT advanced access platform was inserted, and standard 5mm laparoscopic instruments were used. Fifty-nine patients (median age 5 years, 4 months-17 years) met inclusion criteria: 29 nephrectomies, 9 nephroureterectomies, 3 bilateral nephrectomies, 5 heminephrectomies, 5 renal cyst decortications, 3 bilateral gonadectomies, 2 Malone antegrade continence enema, 2 calyceal diverticulectomy, and 1 ovarian detorsion with cystectomy. Median operative times for each case type were comparable to published experiences with traditional laparoscopy. Overall mean and median length of stay was 36.2 hours and 1 day, respectively. There were two complications: port site hernia requiring surgical repair (Clavien IIIb) and a superficial port site infection that resolved with antibiotics (Clavien II). Cosmetic outcomes were subjectively well received by patients and their parents. Operative time was significantly shorter between the first half of the experience and the second half (102 vs 70 minutes, P  <  .05). LESS approach can be broadly applied across many major extirpative and reconstructive procedures within pediatric urology. Our series advances our field's utilization of this technique and its safety. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Stability of detectability over 17 years at a single site and other lizard detection comparisons from Guam

    Science.gov (United States)

    Rodda, Gordon H.; Dean-Bradley, Kathryn; Campbell, Earl W.; Fritts, Thomas H.; Lardner, Bjorn; Yackel Adams, Amy A.; Reed, Robert N.

    2015-01-01

    To obtain quantitative information about population dynamics from counts of animals, the per capita detectabilities of each species must remain constant over the course of monitoring. We characterized lizard detection constancy for four species over 17 yr from a single site in northern Guam, a relatively benign situation because detection was relatively easy and we were able to hold constant the site, habitat type, species, season, and sampling method. We monitored two species of diurnal terrestrial skinks (Carlia ailanpalai [Curious Skink], Emoia caeruleocauda [Pacific Bluetailed Skink]) using glueboards placed on the ground in the shade for 3 h on rainless mornings, yielding 10,286 skink captures. We additionally monitored two species of nocturnal arboreal geckos (Hemidactylus frenatus [Common House Gecko]; Lepidodactylus lugubris [Mourning Gecko]) on the basis of 15,212 sightings. We compared these count samples to a series of complete censuses we conducted from four or more total removal plots (everything removed to mineral soil) totaling 400 m2(about 1% of study site) in each of the years 1995, 1999, and 2012, providing time-stamped quantification of detectability for each species. Unfortunately, the actual population trajectories taken by the four species were masked by unexplained variation in detectability. This observation of debilitating latent variability in lizard detectability under nearly ideal conditions undercuts our trust in population estimation techniques that fail to quantify venue-specific detectability, rely on pooled detection probability estimates, or assume that modulation in predefined environmental covariates suffices for estimating detectability.

  10. Laparoendoscopic single-site surgery for the treatment of different urological pathologies: Defining the learning curve of an experienced laparoscopist.

    Science.gov (United States)

    Abdel-Karim, Aly M; Elhenawy, Ibrahim M; Eid, Ahmed A; Yahia, Elsayed; Elsalmy, Salah A

    2017-09-01

    To define the learning curve of laparoendoscopic single-site surgery (LESS) of an experienced laparoscopist. Patients who had LESS, since its implementation in December 2009 until December 2014, were retrospectively analysed. Procedures were divided into groups of 10 and scored according to the European Scoring System for Laparoscopic Operations in Urology. Different LESS indications were done by one experienced laparoscopist. Technical feasibility, surgical safety, outcome, as well as the number of patients required to achieve professional competence were assessed. In all, 179 patients were included, with mean (SD) age of 36.3 (17.5) years and 25.4% of the patients had had previous surgeries. Upper urinary tract procedures were done in 65.9% of patients and 54.7% of the procedures were extirpative. Both transperitoneal and retroperitoneal LESS were performed in 92.8% and 7.2% of the patients, respectively. The intraoperative and postoperative complication rates were 2.2% and 5.6% (Clavien-Dindo Grade II 3.9% and IIIa 1.7%), respectively. In all, 75% of intraoperative complications and all conversions were reported during the first 30 LESS procedures; despite the significantly higher difficulty score in the subsequent LESS procedures. One 5-mm extra port, conversion to conventional laparoscopy and open surgery was reported in 14%, 1.7%, and 1.1% of the cases, respectively. At mean (SD) follow-up of 39.7 (11.4) months, all the patients that underwent reconstructive LESS procedures but one were successful. In experienced hands, at least 30 LESS procedures are required to achieve professional competence. Although difficult, both conversion and complication rates of LESS are low in experienced hands.

  11. METHOD OF PURIFYING CATALYSTS

    Science.gov (United States)

    Joris, G.G.

    1958-09-01

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

  12. Hydroxide catalysts for lignin depolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, Gregg T; Biddy, Mary J.; Kruger, Jacob S.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-10-17

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  13. Hydroxide catalysts for lignin depolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, Gregg T.; Biddy, Mary J.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-04-25

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  14. Mobile Test Capabilities

    Data.gov (United States)

    Federal Laboratory Consortium — The Electrical Power Mobile Test capabilities are utilized to conduct electrical power quality testing on aircraft and helicopters. This capability allows that the...

  15. New catalysts for miniaturized methanol fuel cells

    DEFF Research Database (Denmark)

    Pedersen, Christoffer Mølleskov

    . The kinetics can however be improved by using a superior catalyst. Therefore, the aim of this thesis is to identify new catalyst material for methanol fuel cells. By analysing the performance of the standard catalysts (PtRu and Pt) currently being applied in methanol fuel cells as anode and cathode......The methanol fuel cell is an interesting energy technology, capable of converting the chemical energy of methanol directly into electricity. The technology is specifically attractive for small mobile applications such as laptops, smartphones, tablets etc. since it offers almost instantaneously...... demonstrated by the Danish Technological Institute; however, for the technology to become more widely adapted, the power density of the fuel cell must be increased. It is well known that a considerable part of the energy from the methanol is lost in the fuel cell during the conversion due to poor kinetics...

  16. Magnetic catalyst bodies

    NARCIS (Netherlands)

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

    1999-01-01

    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

  17. 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...

  18. Nanostructured catalyst supports

    Science.gov (United States)

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

    2012-10-02

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

  19. Catalyst for hydrocarbon conversion

    International Nuclear Information System (INIS)

    Duhaut, P.; Miquel, J.

    1975-01-01

    A description is given for a catalyst and process for hydrocarbon conversions, e.g., reforming. The catalyst contains an alumina carrier, platinum, iridium, at least one metal selected from uranium, vanadium, and gallium, and optionally halogen in the form of metal halide of one of the aforesaid components. (U.S.)

  20. Transumbilical laparoendoscopic single-site radical prostatectomy and cystectomy with the aid of a transurethral port: a feasibility study.

    Science.gov (United States)

    Su, Jian; Zhu, Qingyi; Yuan, Lin; Zhang, Yang; Zhang, Qingling; Wei, Yunfei

    2018-01-01

    To describe the surgical technique and report early outcomes of transurethral assisted laparoendoscopic single-site (LESS) radical prostatectomy (RP) and LESS radical cystectomy (RC) in a single institution. Between December 2014 and March 2016, a total of 114 LESS RPs and RCs were performed, comprising 68 LESS RPs, 38 LESS RCs with cutaneous ureterostomy (CU) and eight LESS RCs with orthotopic ileal neobladder (OIN). Access was achieved via a single-port, with four channels placed through a transumblical incision. After the apex of prostate was separated from the urethra, a self-developed port ('Zhu's port') was inserted through the urethra to facilitate resection of prostate and urethrovesical anastomosis. The peri-operative and postoperative data were collected and analysed retrospectively. Patients were followed up postoperatively for evidence of long-term side effects. All the procedures were completed successfully. No conversion to conventional laparoscopic surgery was necessary. For LESS RP, the average operating time was 152 min. Estimated blood loss was 117 mL. The mean hospital stay was 16.4 days after surgery. For LESS RC with CU and LESS RC with OIN, the mean operating times were 215 and 328 min, mean estimated blood loss was 175 and 252 mL, and mean hospital stay was 9.4 and 18.2 days, respectively. Six patients required blood transfusion (5.26%). Intra-operative complications occurred in two patients (1.75%), and postoperative complications in nine (7.89%). Fourteen out of 68 (20.6%) patients who underwent LESS RP had positive surgical margins. Follow-up ranged from 10 to 30.6 months. In the prostate cancer cases, good urinary control was observed in 35.3%, 97.1% and 100% of patients at 1, 6 and 12 months after the operation, respectively, while biochemical recurrence was observed in 11.8% patients. In the bladder cancer cases, two patients had local recurrence and two patients had distant metastasis. Our results showed that LESS RP and LESS RC

  1. Dynamic capabilities, Marketing Capability and Organizational Performance

    Directory of Open Access Journals (Sweden)

    Adriana Roseli Wünsch Takahashi

    2017-01-01

    Full Text Available The goal of the study is to investigate the influence of dynamic capabilities on organizational performance and the role of marketing capabilities as a mediator in this relationship in the context of private HEIs in Brazil. As a research method we carried out a survey with 316 IES and data analysis was operationalized with the technique of structural equation modeling. The results indicate that the dynamic capabilities have influence on organizational performance only when mediated by marketing ability. The marketing capability has an important role in the survival, growth and renewal on educational services offerings for HEIs in private sector, and consequently in organizational performance. It is also demonstrated that mediated relationship is more intense for HEI with up to 3,000 students and other organizational profile variables such as amount of courses, the constitution, the type of institution and type of education do not significantly alter the results.

  2. 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.

  3. 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

  4. Use of ionic liquids as coordination ligands for organometallic catalysts

    Science.gov (United States)

    Li, Zaiwei [Moreno Valley, CA; Tang, Yongchun [Walnut, CA; Cheng,; Jihong, [Arcadia, CA

    2009-11-10

    Aspects of the present invention relate to compositions and methods for the use of ionic liquids with dissolved metal compounds as catalysts for a variety of chemical reactions. Ionic liquids are salts that generally are liquids at room temperature, and are capable of dissolving a many types of compounds that are relatively insoluble in aqueous or organic solvent systems. Specifically, ionic liquids may dissolve metal compounds to produce homogeneous and heterogeneous organometallic catalysts. One industrially-important chemical reaction that may be catalyzed by metal-containing ionic liquid catalysts is the conversion of methane to methanol.

  5. Study of spent hydrorefining catalysts

    International Nuclear Information System (INIS)

    Gellerman, M.M.; Aliev, R.R.; Sidel'kovskaya, V.G.

    1993-01-01

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

  6. Catalysts for Environmental Remediation

    DEFF Research Database (Denmark)

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

    2013-01-01

    on titania (V2O5-WO3/TiO2) as the example catalyst. The main photocatalysts examined for mineralization of organic compounds were TiO2 and MoS2. It is important to obtain insight into the catalyst structure-to-activity relationship in order to understand and locate the active site(s). In this chapter......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...

  7. Capabilities for Strategic Adaptation

    DEFF Research Database (Denmark)

    Distel, Andreas Philipp

    This dissertation explores capabilities that enable firms to strategically adapt to environmental changes and preserve competitiveness over time – often referred to as dynamic capabilities. While dynamic capabilities being a popular research domain, too little is known about what these capabilities...... are in terms of their constituent elements, where these capabilities come from, and how their effectiveness can be fostered. Thus, the dissertation’s aim is to address these gaps by advancing our understanding of the multilevel aspects and micro-foundations of dynamic capabilities. In doing so, it focuses...... on capabilities for sensing and seizing new business opportunities and reconfiguring corporate resources. More specifically, the dissertation examines the role of key organization members, such as knowledge workers and top managers, in defining and building these capabilities. Moreover, it investigates how...

  8. Catalyst for microelectromechanical systems microreactors

    Science.gov (United States)

    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

    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.

  9. Catalysts and method

    Science.gov (United States)

    Taylor, Charles E.; Noceti, Richard P.

    1991-01-01

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

  10. 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.

  11. Latent olefin metathesis catalysts

    OpenAIRE

    Monsaert, Stijn; Lozano Vila, Ana; Drozdzak, Renata; Van Der Voort, Pascal; Verpoort, Francis

    2009-01-01

    Olefin metathesis is a versatile synthetic tool for the redistribution of alkylidene fragments at carbon-carbon double bonds. This field, and more specifically the development of task-specific, latent catalysts, attracts emerging industrial and academic interest. This tutorial review aims to provide the reader with a concise overview of early breakthroughs and recent key developments in the endeavor to develop latent olefin metathesis catalysts, and to illustrate their use by prominent exampl...

  12. Plasmatron-catalyst system

    Science.gov (United States)

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

    2007-10-09

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

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

    Science.gov (United States)

    Angelici, Robert J.; Gao, Hanrong

    1998-08-04

    The present invention provides new catalyst formats which comprise a supported catalyst tethered to a second and different catalyst by a suitable tethering ligand. A preferred system comprises a heterogeneous supported metal catalyst tethered to a homogeneous catalyst. This combination of homogeneous and heterogeneous catalysts has a sufficient lifetime and unusually high catalytic activity in arene hydrogenations, and potentially many other reactions as well, including, but not limited to hydroformylation, hydrosilation, olefin oxidation, isomerization, hydrocyanation, olefin metathesis, olefin polymerization, carbonylation, enantioselective catalysis and photoduplication. These catalysts are easily separated from the products, and can be reused repeatedly, making these systems very economical.

  14. High temperature durable catalyst development

    Science.gov (United States)

    Snow, G. C.; Tong, H.

    1981-01-01

    A program has been carried out to develop a catalytic reactor capable of operation in environments representative of those anticipated for advanced automotive gas turbine engines. A reactor consisting of a graded cell honeycomb support with a combination of noble metal and metal oxide catalyst coatings was built and successfully operated for 1000 hr. At an air preheat temperature of 740 K and a propane/air ratio of 0.028 by mass, the adiabatic flame temperature was held at about 1700 K. The graded cell monolithic reaction measured 5 cm in diameter by 10.2 cm in length and was operated at a reference velocity of 14.0 m/s at 1 atm. Measured NOx levels remained below 5 ppm, while unburned hydrocarbon concentrations registered near zero and carbon monoxide levels were nominally below 20 ppm.

  15. Catalysts, additives, environment head up CMRA meeting agenda

    International Nuclear Information System (INIS)

    Kiesche, E.S.

    1993-01-01

    Technology leadership in catalyst and additives were hot topics at the Chemical Management and Resources Association's (Staten Island, NY) meeting in Cincinnati last week. In particular, the advent of metallocene single-site catalyst (SSC) are likely to alter the dynamics of the plastics landscape, suggest Gregory McPike, v.p./Exxpol at Exxon Chemical. As SSC technology - which allows accurate tailoring of polymers - gains momentum, the delineation between SSC licensers and licensees will increase, McPike says. And he expects that with only few producers able to afford the huge amount of time and money it takes to develop metallocene technology, there will be proliferation of alliances; Exxon itself has a partnership with Mitsui to develop gas-phase polyethylene. But McPike also expects higher profits and growth for those with metallocene technology, as SSC-based polymers penetrate other than polyolefins. McPike says Exxon plans to license the technology in the next two years for commodity markets. Increased environmental regulations are creating opportunities in catalysts and in water treatment chemicals, speakers noted

  16. CATALYSTS NHI Thermochemical Systems FY 2009 Year-End Report

    Energy Technology Data Exchange (ETDEWEB)

    Daniel M. Ginosar

    2009-09-01

    , development and testing of metal oxide based H2SO4 catalysts, support of the ILS for catalyst studies, conducting a long term catalyst stability test at anticipated operating temperatures and pressures, and developing capabilities for conducting pressurized catalyst tests.

  17. Evidence of Scrambling over Ruthenium-based Catalysts in Supercritical-water Gasification

    DEFF Research Database (Denmark)

    Peterson, Andrew A.; Dreher, Marian; Wambach, Jörg

    2012-01-01

    Catalytic processes that employ Ru catalysts in supercritical water have been shown to be capable of converting organics, such as wood waste, into synthetic natural gas (CH4) with high efficiencies at relatively moderate temperatures of around 400°C. However, the exact roles of the catalyst and t...... that a characteristic of an effective catalyst for supercritical water gasification to methane is its ability to promote rapid equilibria through scrambling mechanisms....

  18. Magnetic and dendritic catalysts.

    Science.gov (United States)

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

    2015-07-21

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

  19. Developing Alliance Capabilities

    DEFF Research Database (Denmark)

    Heimeriks, Koen H.; Duysters, Geert; Vanhaverbeke, Wim

    This paper assesses the differential performance effects of learning mechanisms on the development of alliance capabilities. Prior research has suggested that different capability levels could be identified in which specific intra-firm learning mechanisms are used to enhance a firm's alliance...... capability. However, empirical testing in this field is scarce and little is known as to what extent different learning mechanisms are indeed useful in advancing a firm's alliance capability. This paper analyzes to what extent intra-firm learning mechanisms help firms develop their alliance capability....... Differential learning may explain in what way firms yield superior returns from their alliances in comparison to competitors. The empirical results show that different learning mechanisms have different performance effects at different stages of the alliance capability development process. The main lesson from...

  20. Catalyst component interactions in nickel/alumina catalyst

    Directory of Open Access Journals (Sweden)

    Kiš Erne E.

    2007-01-01

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

  1. Supported organoiridium catalysts for alkane dehydrogenation

    Science.gov (United States)

    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.

  2. Development of a novel robotic platform with controllable stiffness manipulation arms for laparoendoscopic single-site surgery (LESS).

    Science.gov (United States)

    Wang, Jianchen; Wang, Shuxin; Li, Jinhua; Ren, Xiangyun; Briggs, Randall Miller

    2018-02-01

    For current LESS robotic systems, the trade-off between dexterity and payload capability is always present. This paper presents a novel LESS robotic platform equipped with controllable stiffness manipulation arms. Each manipulation arm with an articulated section and a controllable stiffness continuum section (CSCS) can be switched between a 7-DoF compliant status and 5-DoF rigid status according to the operation requirement. Screw theory and product exponential formula are used to quantify the kinematic performance. The stiffness of the manipulation arm promotes 3.03 to 4.12 times from compliant to rigid CSCS with maximum payload of 10 N in rigid status. The shortest rigid/compliant switching time is 5 s. The precision of a tracking test and an ex vivo procedure verified the accuracy and effectiveness of the controllable stiffness manipulation arms. This robot could potentially improve the surgical performance and further expand robotic LESS procedures. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Dynamic Capabilities and Performance

    DEFF Research Database (Denmark)

    Wilden, Ralf; Gudergan, Siegfried P.; Nielsen, Bo Bernhard

    2013-01-01

    are contingent on the competitive intensity faced by firms. Our findings demonstrate the performance effects of internal alignment between organizational structure and dynamic capabilities, as well as the external fit of dynamic capabilities with competitive intensity. We outline the advantages of PLS...

  4. Telematics Options and Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, Cabell [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-05

    This presentation describes the data tracking and analytical capabilities of telematics devices. Federal fleet managers can use the systems to keep their drivers safe, maintain a fuel efficient fleet, ease their reporting burden, and save money. The presentation includes an example of how much these capabilities can save fleets.

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

    Science.gov (United States)

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

    2002-08-27

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

  6. Oxide Nanocrystal Model Catalysts.

    Science.gov (United States)

    Huang, Weixin

    2016-03-15

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

  7. Heterogenization of Homogeneous Catalysts: the Effect of the Support

    Energy Technology Data Exchange (ETDEWEB)

    Earl, W.L.; Ott, K.C.; Hall, K.A.; de Rege, F.M.; Morita, D.K.; Tumas, W.; Brown, G.H.; Broene, R.D.

    1999-06-29

    We have studied the influence of placing a soluble, homogeneous catalyst onto a solid support. We determined that such a 'heterogenized' homogeneous catalyst can have improved activity and selectivity for the asymmetric hydrogenation of enamides to amino acid derivatives. The route of heterogenization of RhDuPhos(COD){sup +} cations occurs via electrostatic interactions with anions that are capable of strong hydrogen bonding to silica surfaces. This is a novel approach to supported catalysis. Supported RhDuPhos(COD){sup +} is a recyclable, non-leaching catalyst in non-polar media. This is one of the few heterogenized catalysts that exhibits improved catalytic performance as compared to its homogeneous analog.

  8. Fuel cell catalyst degradation

    DEFF Research Database (Denmark)

    Arenz, Matthias; Zana, Alessandro

    2016-01-01

    Fuel cells are an important piece in our quest for a sustainable energy supply. Although there are several different types of fuel cells, the by far most popular is the proton exchange membrane fuel cell (PEMFC). Among its many favorable properties are a short start up time and a high power density...... increasing focus. Activity of the catalyst is important, but stability is essential. In the presented perspective paper, we review recent efforts to investigate fuel cell catalysts ex-situ in electrochemical half-cell measurements. Due to the amount of different studies, this review has no intention to give...

  9. 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.

  10. PREPARATION AND CHARACTERIZATION THE NON-SULFIDED METAL CATALYST: Ni/USY and NiMo/USY

    Directory of Open Access Journals (Sweden)

    Khoirina Dwi Nugrahaningtyas

    2010-06-01

    Full Text Available The two-new catalysts had been prepared by using the impregnation method according to Nugrahaningtyas [6] and Li [4]. One catalyst is of Nickel (Ni, supported on Ultra Stable Zeolite Y (USY, whereas the other one is NiMo supported on same supporting agent. These new catalysts are expected to be more effective when applied on the hydrotreatment reaction in standpoint of its capabilities on removing the unwanted-heteroatom. Characterization those two types of catalysts then carried out by using the criteria of acidity, porosity and, metal content. The result shows that these non-sulfide catalysts have several good characters that supporting their usefulness in hydrotreatment-catalytic reaction. In addition, catalyst NiMo/USY - 1 performs many ideal criteria as the best functional catalyst.   Keywords: Non-sulfided Catalyst, hydro-treating, preparation, characterization

  11. Investigation of heterogeneous solid acid catalyst performance on low grade feedstocks for biodiesel production: A review

    International Nuclear Information System (INIS)

    Mansir, Nasar; Taufiq-Yap, Yun Hin; Rashid, Umer; Lokman, Ibrahim M.

    2017-01-01

    Highlights: • Solid acid catalysts are proficient to esterifying high free fatty acid feedstocks to biodiesel. • Heterogeneous catalysts have the advantage of easy separation and reusability. • Heterogeneous basic catalysts have limitations due to high FFA of low cost feedstocks. • Solid catalysts having acid and base sites reveal better catalyst for biodiesel production. - Abstract: The conventional fossil fuel reserves are continually declining worldwide and therefore posing greater challenges to the future of the energy sources. Biofuel alternatives were found promising to replace the diminishing fossil fuels. However, conversion of edible vegetable oils to biodiesel using homogeneous acids and base catalysts is now considered as indefensible for the future particularly due to food versus fuel competition and other environmental problems related to catalyst system and feedstock. This review has discussed the progression in research and growth related to heterogeneous catalysts used for biodiesel production for low grade feedstocks. The heterogeneous base catalysts have revealed effective way to produce biodiesel, but it has the limitation of being sensitive to high free fatty acid (FFA) or low grade feedstocks. Alternatively, solid acid catalysts are capable of converting the low grade feedstocks to biodiesel in the presence of active acid sites. The paper presents a comprehensive review towards the investigation of solid acid catalyst performance on low grade feedstock, their category, properties, advantages, limitations and possible remedy to their drawbacks for biodiesel production.

  12. Overcoming the Instability of Nanoparticle-Based Catalyst Films in Alkaline Electrolyzers by using Self-Assembling and Self-Healing Films

    NARCIS (Netherlands)

    Barwe, Stefan; Masa, Justus; Andronescu, Corina; Mei, Bastian; Schuhmann, Wolfgang; Ventosa, Edgar

    2017-01-01

    Engineering stable electrodes using highly active catalyst nanopowders for electrochemical water splitting remains a challenge. We report an innovative and general approach for attaining highly stable catalyst films with self-healing capability based on the in situ self-assembly of catalyst

  13. 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....

  14. The Influence of Ziegler-Natta and Metallocene Catalysts on Polyolefin Structure, Properties, and Processing Ability

    Directory of Open Access Journals (Sweden)

    Ahmad Shamiri

    2014-07-01

    Full Text Available 50 years ago, Karl Ziegler and Giulio Natta were awarded the Nobel Prize for their discovery of the catalytic polymerization of ethylene and propylene using titanium compounds and aluminum-alkyls as co-catalysts. Polyolefins have grown to become one of the biggest of all produced polymers. New metallocene/methylaluminoxane (MAO catalysts open the possibility to synthesize polymers with highly defined microstructure, tacticity, and steroregularity, as well as long-chain branched, or blocky copolymers with excellent properties. This improvement in polymerization is possible due to the single active sites available on the metallocene catalysts in contrast to their traditional counterparts. Moreover, these catalysts, half titanocenes/MAO, zirconocenes, and other single site catalysts can control various important parameters, such as co-monomer distribution, molecular weight, molecular weight distribution, molecular architecture, stereo-specificity, degree of linearity, and branching of the polymer. However, in most cases research in this area has reduced academia as olefin polymerization has seen significant advancements in the industries. Therefore, this paper aims to further motivate interest in polyolefin research in academia by highlighting promising and open areas for the future.

  15. The Influence of Ziegler-Natta and Metallocene Catalysts on Polyolefin Structure, Properties, and Processing Ability

    Science.gov (United States)

    Shamiri, Ahmad; Chakrabarti, Mohammed H.; Jahan, Shah; Hussain, Mohd Azlan; Kaminsky, Walter; Aravind, Purushothaman V.; Yehye, Wageeh A.

    2014-01-01

    50 years ago, Karl Ziegler and Giulio Natta were awarded the Nobel Prize for their discovery of the catalytic polymerization of ethylene and propylene using titanium compounds and aluminum-alkyls as co-catalysts. Polyolefins have grown to become one of the biggest of all produced polymers. New metallocene/methylaluminoxane (MAO) catalysts open the possibility to synthesize polymers with highly defined microstructure, tacticity, and steroregularity, as well as long-chain branched, or blocky copolymers with excellent properties. This improvement in polymerization is possible due to the single active sites available on the metallocene catalysts in contrast to their traditional counterparts. Moreover, these catalysts, half titanocenes/MAO, zirconocenes, and other single site catalysts can control various important parameters, such as co-monomer distribution, molecular weight, molecular weight distribution, molecular architecture, stereo-specificity, degree of linearity, and branching of the polymer. However, in most cases research in this area has reduced academia as olefin polymerization has seen significant advancements in the industries. Therefore, this paper aims to further motivate interest in polyolefin research in academia by highlighting promising and open areas for the future. PMID:28788120

  16. Biomass Conversion over Heteropoly Acid Catalysts

    KAUST Repository

    Zhang, Jizhe

    2015-04-01

    (Au/Cs2HPW12O40) that enabled the selective conversion of cellobiose to gluconic acid with a very high yield of 96.4% (Chapter II); we realized a direct oxidative conversion of cellulose to glycolic acid (yield of 49.3 %) in a water medium for the first time, by using a phosphomolybdic acid catalyst (chapter III); we found that a vanadium-substituted phosphomolybdic acid catalyst (H4PVMo11O40) is capable of converting various biomass-derived substrates to formic acid and acetic acid with high selectivity, and under optimized reaction conditions, high yield of formic acid (67.8%) can be obtained from cellulose (chapter IV); we discovered that the vanadium-substituted phosphomolybdic acids can also selectively oxidize glycerol, a low-cost by-product of biodiesel, to formic acid, and interestingly this conversion can be performed in highly concentration aqueous solution (glycerol: water = 50: 50), giving rise to exceptionally high conversion efficiency (chapter V). These results reveal that HPAs are useful and suitable catalysts for selective oxidation of biomass, and that the reaction pathway is largely determined by the type of addenda atom in the HPA catalyst. The optimization of the reaction conditions and processes in these systems are also discussed in this thesis.

  17. 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.

  18. 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.

  19. Sabatier Catalyst Poisoning Investigation

    Science.gov (United States)

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

    2013-01-01

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

  20. ALKALI RESISTANT CATALYST

    DEFF Research Database (Denmark)

    2008-01-01

    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...

  1. Resources, constraints and capabilities

    NARCIS (Netherlands)

    Dhondt, S.; Oeij, P.R.A.; Schröder, A.

    2018-01-01

    Human and financial resources as well as organisational capabilities are needed to overcome the manifold constraints social innovators are facing. To unlock the potential of social innovation for the whole society new (social) innovation friendly environments and new governance structures

  2. Engineering Capabilities and Partnerships

    Science.gov (United States)

    Poulos, Steve

    2010-01-01

    This slide presentation reviews the engineering capabilities at Johnson Space Center, The presentation also reviews the partnerships that have resulted in successfully designed and developed projects that involved commercial and educational institutions.

  3. CASL Dakota Capabilities Summary

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Brian M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Simmons, Chris [Univ. of Texas, Austin, TX (United States); Williams, Brian J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-10

    The Dakota software project serves the mission of Sandia National Laboratories and supports a worldwide user community by delivering state-of-the-art research and robust, usable software for optimization and uncertainty quantification. These capabilities enable advanced exploration and riskinformed prediction with a wide range of computational science and engineering models. Dakota is the verification and validation (V&V) / uncertainty quantification (UQ) software delivery vehicle for CASL, allowing analysts across focus areas to apply these capabilities to myriad nuclear engineering analyses.

  4. Noble metal ionic catalysts.

    Science.gov (United States)

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

    2009-06-16

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

  5. Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

    Science.gov (United States)

    Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

    2017-05-09

    Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

  6. Space Logistics: Launch Capabilities

    Science.gov (United States)

    Furnas, Randall B.

    1989-01-01

    The current maximum launch capability for the United States are shown. The predicted Earth-to-orbit requirements for the United States are presented. Contrasting the two indicates the strong National need for a major increase in Earth-to-orbit lift capability. Approximate weights for planned payloads are shown. NASA is studying the following options to meet the need for a new heavy-lift capability by mid to late 1990's: (1) Shuttle-C for near term (include growth versions); and (2) the Advanced Lauching System (ALS) for the long term. The current baseline two-engine Shuttle-C has a 15 x 82 ft payload bay and an expected lift capability of 82,000 lb to Low Earth Orbit. Several options are being considered which have expanded diameter payload bays. A three-engine Shuttle-C with an expected lift of 145,000 lb to LEO is being evaluated as well. The Advanced Launch System (ALS) is a potential joint development between the Air Force and NASA. This program is focused toward long-term launch requirements, specifically beyond the year 2000. The basic approach is to develop a family of vehicles with the same high reliability as the Shuttle system, yet offering a much greater lift capability at a greatly reduced cost (per pound of payload). The ALS unmanned family of vehicles will provide a low end lift capability equivalent to Titan IV, and a high end lift capability greater than the Soviet Energia if requirements for such a high-end vehicle are defined.In conclusion, the planning of the next generation space telescope should not be constrained to the current launch vehicles. New vehicle designs will be driven by the needs of anticipated heavy users.

  7. Well-defined silica supported aluminum hydride: another step towards the utopian single site dream?† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc02276b Click here for additional data file.

    Science.gov (United States)

    Werghi, Baraa; Bendjeriou-Sedjerari, Anissa; Sofack-Kreutzer, Julien; Jedidi, Abdesslem; Abou-Hamad, Edy

    2015-01-01

    of a strained siloxane bridge, Si–O–Si but with two different mechanisms, showing that the reality of “single site” catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O–Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a β-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al–H bond and a O–Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10–5 mbar) generates Al–H through a β-H elimination of isobutyl fragment. These supported well-defined Al–H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27Al–1H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system. PMID:28757945

  8. Capabilities for innovation

    DEFF Research Database (Denmark)

    Nielsen, Peter; Nielsen, René Nesgaard; Bamberger, Simon Grandjean

    2012-01-01

    and in particular their ability to develop firm-specific innovative capabilities through employee participation and creation of innovative workplaces. In this article, we argue that national institutional conditions can play an enhancing or hampering role in this. Especially the norms and values governing relations...... on some of the important institutional conditions in Danish firms derived from the Nordic model, such as the formal and informal relations of cooperation between employers and employees in firms and their function in building capabilities for innovation. The foundation of the empirical analysis...... is a survey that collected information from 601 firms belonging to the private urban sector in Denmark. The survey was carried out in late 2010. Keywords: dynamic capabilities/innovation/globalization/employee/employer cooperation/Nordic model Acknowledgment: The GOPA study was financed by grant 20080053113...

  9. Technological Capability's Predictor Variables

    Directory of Open Access Journals (Sweden)

    Fernanda Maciel Reichert

    2011-03-01

    Full Text Available The aim of this study was to identify the factors that influence in configuration of the technological capability of companies in sectors with medium-low technological intensity. To achieve the goal proposed in this article a survey was carried out. Based on the framework developed by Lall (1992 which classifies firms in basic, intermediate and advanced level of technological capability; it was found that the predominant technological capability is intermediate, with 83.7% of respondent companies (plastics companies in Brazil. It is believed that the main contribution of this study is the finding that the dependent variable named “Technological Capability” can be explained at a rate of 65% by six variables: development of new processes; selection of the best equipment supplier; sales of internally developed new technology to third parties; design and manufacture of equipment; study of the work methods and perform inventory control; and improvement of product quality.

  10. Campus Capability Plan

    Energy Technology Data Exchange (ETDEWEB)

    Adams, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Arsenlis, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bailey, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bergman, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brase, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brenner, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Camara, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Carlton, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cheng, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chrzanowski, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Colson, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); East, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Farrell, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferranti, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gursahani, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hansen, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Helms, L. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hernandez, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jeffries, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Larson, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lu, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McNabb, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mercer, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Skeate, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sueksdorf, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zucca, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Le, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ancria, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Scott, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Leininger, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gagliardi, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gash, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bronson, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chung, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hobson, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Meeker, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanchez, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zagar, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Quivey, B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sommer, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Atherton, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-06

    Lawrence Livermore National Laboratory Campus Capability Plan for 2018-2028. Lawrence Livermore National Laboratory (LLNL) is one of three national laboratories that are part of the National Nuclear Security Administration. LLNL provides critical expertise to strengthen U.S. security through development and application of world-class science and technology that: Ensures the safety, reliability, and performance of the U.S. nuclear weapons stockpile; Promotes international nuclear safety and nonproliferation; Reduces global danger from weapons of mass destruction; Supports U.S. leadership in science and technology. Essential to the execution and continued advancement of these mission areas are responsive infrastructure capabilities. This report showcases each LLNL capability area and describes the mission, science, and technology efforts enabled by LLNL infrastructure, as well as future infrastructure plans.

  11. Management Innovation Capabilities

    DEFF Research Database (Denmark)

    Harder, Mie

    , the paper introduces the concept of management innovation capabilities which refers to the ability of a firm to purposefully create, extend and modify its managerial resource base to address rapidly changing environments. Drawing upon behavioral theory of the firm and the dynamic capabilities framework......Management innovation is the implementation of a new management practice, process, technique or structure that significantly alters the way the work of management is performed. This paper presents a typology categorizing management innovation along two dimensions; radicalness and complexity. Then......, the paper proposes a model of the foundations of management innovation. Propositions and implications for future research are discussed....

  12. Sandia QIS Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Richard P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    Sandia National Laboratories has developed a broad set of capabilities in quantum information science (QIS), including elements of quantum computing, quantum communications, and quantum sensing. The Sandia QIS program is built atop unique DOE investments at the laboratories, including the MESA microelectronics fabrication facility, the Center for Integrated Nanotechnologies (CINT) facilities (joint with LANL), the Ion Beam Laboratory, and ASC High Performance Computing (HPC) facilities. Sandia has invested $75 M of LDRD funding over 12 years to develop unique, differentiating capabilities that leverage these DOE infrastructure investments.

  13. Dynamics of Catalyst Nanoparticles

    DEFF Research Database (Denmark)

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

    Transmission electron microscopy (TEM) is extensively used in catalysis research. Recent developments in aberration correction allows imaging surface structures with unprecedented resolution. Using these correctors in conjunction with environmental TEM (ETEM), where imaging of materials can be done...... 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...

  14. Mesoporous molecular sieve catalysts

    DEFF Research Database (Denmark)

    Højholt, Karen Thrane

    This thesis deals with a very specific class of molecular sieves known as zeolites. Zeolites are a class of crystalline aluminosilicates characterised by pores or cavities of molecular dimensions as part of their crystal structure. In this work zeolites were modified for the use and understanding...... of different catalytic applications. Primarily the zeolites were modified regarding the porosity and the introduction of metals to the framework. The obtained materials were used as solid acid catalysts, as an inert matrix for stabilising metal nanoparticles and as an anchoring material for molecular metal....... Furthermore, preliminary work was done using mesoporous ZSM-5 zeolites as support material for anchoring molecular CoMo6 species for the application as potential bi-functional catalyst in simultaneous hydrodesulfurisation (HDS) and hydrocracking. HDS activity tests revealed that the anchoring improved...

  15. Photo catalyst; Ko shokubai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-01

    While titanium oxide is excited by the light, electrons of titanium oxide are taken away by the light energy to form positive holes. Water will be decomposed into hydrogen ion and hydroxy radical (OH) by these positive holes. This hydroxy radical is a strong reactive substance called active oxygen, it decomposes organisms. Besides this photo- catalyst function, the titanium oxide can also make surface of a substance superhydrophilic. The super hydrophilicity results in not forming water drops on the glass surface but spreading all over the surface to prevent a covering of fog on the glass surface. The published patents concerning the photo catalysts were 593 from Jan. 1998 to Jan. 1999. The applicant order is the first TOTO 143, the second Daikin Industry 19, the third Toshiba Raitech, Nitto Denko, Hitachi 17 respectively. (NEDO)

  16. High-Activity Dealloyed Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kongkanand, Anusorn [General Motors LLC, Pontiac, MI (United States)

    2014-09-30

    Reduction of costly Pt usage in proton exchange membrane fuel cell electrodes is one of the major challenges towards development and commercialization of fuel cell vehicles. Although few have met the initial-kinetic activity requirements in a realistic fuel cell device, no catalyst material has ever met the demanding fuel cell durability targets set by DOE. In this project, a team of 4 universities and 2 companies came together to investigate a concept that appeared promising in preliminary non-fuel cell tests then to further develop the catalyst to a mature level ready for vehicle implementation. The team consists of academia with technical leadership in their respective areas, a catalyst supplier, and a fuel cell system integrator.The tightly collaborative project enabled development of a highly active and durable catalyst with performance that significantly exceeds that of previous catalysts and meets the DOE targets for the first time (Figure 1A). The catalyst was then further evaluated in full-active-area stack in a realistic vehicle operating condition (Figure 1B). This is the first public demonstration that one can realize the performance benefit and Pt cost reduction over a conventional pure Pt catalyst in a long-term realistic PEMFC system. Furthermore, systematic analyses of a range of catalysts with different performance after fuel cell testing allowed for correlation between catalyst microstructure and its electrocatalytic activity and durability. This will in turn aid future catalyst development.

  17. PHENOL OXIDATION USING NATURAL ZEOLITE SUPPORTED METAL ION CATALYST

    Directory of Open Access Journals (Sweden)

    Sri Wardhani

    2010-06-01

    Full Text Available Phenol which contained in waste water has to be reduced and it could be done by oxygen oxidation.  In order to increase the rate of reaction it was needed a catalyst. In this research the capability of various catalysts, namely zeolite-Zn(II, zeolite-Cu(II and zeolite-Co(IIin oxidation of phenol has been investigated. The aim of this research was to study the type of metal ion catalyst towards the percentage of oxidated phenol. The oxidation process were carried out in an aqueous phenol of 100 ppm with oxygen flow rate of 200 mL/min. in the presence of catalysts with 0.2M of initial impregnation concentration. The capabilities of catalysts were performed by calculating the activation energy and it was done at two different temperatures, i.e. 70 and 90 oC. The percentage of oxidated phenol was determinated by measuring its concentration using UV-VIS spectrophotometer. In addition, the impregnated metal was calculated by measuring the ion concentration remains in the filtrate solution and it was determined using Atomic Absorption Spectrophotometer. The results showed that metal ion types affected the catalytic activity. The order of phenol oxidationactivity decreased as Co(II > Cu(II > Zn(II. The surface characteristics of catalysts were supported by pore volume and pore diameter i.e 0.009 cm3/g and 16.59 Å for Zn(II whereas specific surface area was 10.32 m2/g for Zn(II, 0.004 cm3/g and 24.37 Å for Cu(II whereas specific surface area was 3.57 m2/g for Cu(II, 0.001 cm3/g and 19.63 Å for Co(II whereas specific surface area was 10.26m2/g for Co(II.   Keywords: phenol,natural zeolite, catalyst, oxidation

  18. Deactivation of Oxidation Catalysts

    Science.gov (United States)

    1991-05-01

    been observed to decrease CO oxidation even at 500TC ( Farrauto and Wedding, 1973, p. 254) by a sulfate formation mechanism, it is likely that the...sulfated CoO, in the study of Farrauto and Wedding (1973) and that no deactivation was observed in the previously discussed study by Pope et al...This is attributed to the adsorption of HO on the catalyst surface which competes with the adsorption of ethanol. Farrauto and Wedding (1973) studied

  19. 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.

  20. Catalyst in Basic Oleochemicals

    OpenAIRE

    Eva Suyenty; Herlina Sentosa; Mariani Agustine; Sandy Anwar; Abun Lie; Erwin Sutanto

    2007-01-01

    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 oleochemic...

  1. 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.

  2. Catalyst component interactions in nickel/alumina catalyst

    OpenAIRE

    Kiš Erne E.; Lazić Matilda M.; Bošković Goran C.

    2007-01-01

    The influence of nickel loading (5; 10; 20 wt% Ni), temperature of heat treatment (400; 700; 1100°C) and way of catalyst preparation on the catalyst component interactions (CCI) in the impregnated, mechanical powder mixed and co-precipitated catalyst was investigated. For sample characterization, low temperature nitrogen adsorption (LTNA) and X-ray diffraction (XRD) were applied. Significant differences were revealed, concerning CCI in dependence of nickel loading, temperature of heat treatme...

  3. Building Service Provider Capabilities

    DEFF Research Database (Denmark)

    Brandl, Kristin; Jaura, Manya; Ørberg Jensen, Peter D.

    In this paper we study whether and how the interaction between clients and the service providers contributes to the development of capabilities in service provider firms. In situations where such a contribution occurs, we analyze how different types of activities in the production process of the ...

  4. Capabilities Composition (Briefing Charts)

    Science.gov (United States)

    2009-04-22

    and support , , processes (including ITIL v3) • Understanding of Governance is still evolving Engineering Acquisition and Operational Governance...L – Logistics • NC – Net-Centric • CPM – Capability Portfolio Management • ITIL v3 – Information Technology • ONR – Office of Naval Research

  5. Metrology Measurement Capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Glen E. Gronniger

    2007-10-02

    This document contains descriptions of Federal Manufacturing & Technologies (FM&T) Metrology capabilities, traceability flow charts, and the measurement uncertainty of each measurement capability. Metrology provides NIST traceable precision measurements or equipment calibration for a wide variety of parameters, ranges, and state-of-the-art uncertainties. Metrology laboratories conform to the requirements of the Department of Energy Development and Production Manual Chapter 13.2, ANSI/ISO/IEC ANSI/ISO/IEC 17025:2005, and ANSI/NCSL Z540-1. FM&T Metrology laboratories are accredited by NVLAP for the parameters, ranges, and uncertainties listed in the specific scope of accreditation under NVLAP Lab code 200108-0. See the Internet at http://ts.nist.gov/Standards/scopes/2001080.pdf. These parameters are summarized. The Honeywell Federal Manufacturing & Technologies (FM&T) Metrology Department has developed measurement technology and calibration capability in four major fields of measurement: (1) Mechanical; (2) Environmental, Gas, Liquid; (3) Electrical (DC, AC, RF/Microwave); and (4) Optical and Radiation. Metrology Engineering provides the expertise to develop measurement capabilities for virtually any type of measurement in the fields listed above. A strong audit function has been developed to provide a means to evaluate the calibration programs of our suppliers and internal calibration organizations. Evaluation includes measurement audits and technical surveys.

  6. Capabilities for Intercultural Dialogue

    Science.gov (United States)

    Crosbie, Veronica

    2014-01-01

    The capabilities approach offers a valuable analytical lens for exploring the challenge and complexity of intercultural dialogue in contemporary settings. The central tenets of the approach, developed by Amartya Sen and Martha Nussbaum, involve a set of humanistic goals including the recognition that development is a process whereby people's…

  7. The Capability Approach

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2011-01-01

    textabstract In its most general description, the capability approach is a flexible and multi-purpose normative framework, rather than a precise theory of well-being, freedom or justice. At its core are two normative claims: first, the claim that the freedom to achieve well-being is of primary

  8. Capitalizing on capabilities.

    Science.gov (United States)

    Ulrich, Dave; Smallwood, Norm

    2004-06-01

    By making the most of organizational capabilities--employees' collective skills and fields of expertise--you can dramatically improve your company's market value. Although there is no magic list of proficiencies that every organization needs in order to succeed, the authors identify 11 intangible assets that well-managed companies tend to have: talent, speed, shared mind-set and coherent brand identity, accountability, collaboration, learning, leadership, customer connectivity, strategic unity, innovation, and efficiency. Such companies typically excel in only three of these capabilities while maintaining industry parity in the other areas. Organizations that fall below the norm in any of the 11 are likely candidates for dysfunction and competitive disadvantage. So you can determine how your company fares in these categories (or others, if the generic list doesn't suit your needs), the authors explain how to conduct a "capabilities audit," describing in particular the experiences and findings of two companies that recently performed such audits. In addition to highlighting which intangible assets are most important given the organization's history and strategy, this exercise will gauge how well your company delivers on its capabilities and will guide you in developing an action plan for improvement. A capabilities audit can work for an entire organization, a business unit, or a region--indeed, for any part of a company that has a strategy to generate financial or customer-related results. It enables executives to assess overall company strengths and weaknesses, senior leaders to define strategy, midlevel managers to execute strategy, and frontline leaders to achieve tactical results. In short, it helps turn intangible assets into concrete strengths.

  9. Organometallic catalysts for primary phosphoric acid fuel cells

    Science.gov (United States)

    Walsh, Fraser

    1987-01-01

    A continuing effort by the U.S. Department of Energy to improve the competitiveness of the phosphoric acid fuel cell by improving cell performance and/or reducing cell cost is discussed. Cathode improvement, both in performance and cost, available through the use of a class of organometallic cathode catalysts, the tetraazaannulenes (TAAs), was investigated. A new mixed catalyst was identified which provides improved cathode performance without the need for the use of a noble metal. This mixed catalyst was tested under load for 1000 hr. in full cell at 160 to 200 C in phosphoric acid H3PO4, and was shown to provide stable performance. The mixed catalyst contains an organometallic to catalyze electroreduction of oxygen to hydrogen peroxide and a metal to catalyze further electroreduction of the hydrogen peroxide to water. Cathodes containing an exemplar mixed catalyst (e.g., Co bisphenyl TAA/Mn) operate at approximately 650 mV vs DHE in 160 C, 85% H3PO4 with oxygen as reactant. In developing this mixed catalyst, a broad spectrum of TAAs were prepared, tested in half-cell and in a rotating ring-disk electrode system. TAAs found to facilitate the production of hydrogen peroxide in electroreduction were shown to be preferred TAAs for use in the mixed catalyst. Manganese (Mn) was identified as a preferred metal because it is capable of catalyzing hydrogen peroxide electroreduction, is lower in cost and is of less strategic importance than platinum, the cathode catalyst normally used in the fuel cell.

  10. Dispersion enhanced metal/zeolite catalysts

    Science.gov (United States)

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

    1987-01-01

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

  11. Non-PGM cell catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Elvington, M. [Savannah River Consulting, Aiken, SC (United States); Ganesan, P. [Savannah River Consulting, Aiken, SC (United States)

    2017-09-27

    A unique approach has been developed to probe the non-PGM catalyst active site for the Oxygen Reduction Reaction (ORR) for PEMFCs. Iron based functionalities have been engineered into a variety of catalysts to evaluate their impact on activity for the ORR. A series of high surface area catalysts were synthesized and the impact of the chemical structure on the electrochemical and electrocatalytic properties was investigated. Elemental and surface analyses of the prepared catalysts reveal the incorporation of iron in a targeted and controlled manner. A high surface area framework catalyst was prepared that shows exceptional activity, comparable to state-of-the-art materials. The results of this research project provided critical seed data for the newly awarded ElectroCat project, which focuses on rationally designed framework catalysts for the oxygen reduction reaction.

  12. Hyperfine interactions in metallic catalysts

    International Nuclear Information System (INIS)

    Saitovitch, Henrique; Silva, Paulo R.J.; Passos, Fabio B.

    2005-01-01

    Heterogeneous catalysts are of fundamental importance in several modern chemical processes. The characterization of catalysts is an issue of very present interest as it can provide a better understanding of the fundamental aspects of the catalytic phenomena, thus helping in the development of more efficient catalysts. In order to extend and improve the characterization of catalysts, new and less conventional methods are being applied, such as nuclear spectroscopies. In this paper we focus on the application of angular correlation, with can be used to resolve different local environments of probe atoms in solids and can be applied, as shown here, in the characterization of heterogeneous catalysts. A brief theoretical introduction is given and experimental results related to catalytic systems of alumina and niobia-supported Pt-In and Pd-In catalysts are presented. (author)

  13. 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.

  14. Oxygen-reducing catalyst layer

    Science.gov (United States)

    O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

    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.

  15. Catalyst systems and uses thereof

    Science.gov (United States)

    Ozkan, Umit S [Worthington, OH; Holmgreen, Erik M [Columbus, OH; Yung, Matthew M [Columbus, OH

    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.

  16. Final Technical Report: Metal—Organic Surface Catalyst for Low-temperature Methane Oxidation: Bi-functional Union of Metal—Organic Complex and Chemically Complementary Surface

    Energy Technology Data Exchange (ETDEWEB)

    Tait, Steven L. [Indiana Univ., Bloomington, IN (United States)

    2016-10-01

    Stabilization and chemical control of transition metal centers is a critical problem in the advancement of heterogeneous catalysts to next-generation catalysts that exhibit high levels of selectivity, while maintaining strong activity and facile catalyst recycling. Supported metal nanoparticle catalysts typically suffer from having a wide range of metal sites with different coordination numbers and varying chemistry. This project is exploring new possibilities in catalysis by combining features of homogeneous catalysts with those of heterogeneous catalysts to develop new, bi-functional systems. The systems are more complex than traditional heterogeneous catalysts in that they utilize sequential active sites to accomplish the desired overall reaction. The interaction of metal—organic catalysts with surface supports and their interactions with reactants to enable the catalysis of critical reactions at lower temperatures are at the focus of this study. Our work targets key fundamental chemistry problems. How do the metal—organic complexes interact with the surface? Can those metal center sites be tuned for selectivity and activity as they are in the homogeneous system by ligand design? What steps are necessary to enable a cooperative chemistry to occur and open opportunities for bi-functional catalyst systems? Study of these systems will develop the concept of bringing together the advantages of heterogeneous catalysis with those of homogeneous catalysis, and take this a step further by pursuing the objective of a bi-functional system. The use of metal-organic complexes in surface catalysts is therefore of interest to create well-defined and highly regular single-site centers. While these are not likely to be stable in the high temperature environments (> 300 °C) typical of industrial heterogeneous catalysts, they could be applied in moderate temperature reactions (100-300 °C), made feasible by lowering reaction temperatures by better catalyst control. They also

  17. Reuse of Hydrotreating Spent Catalyst

    International Nuclear Information System (INIS)

    Habib, A.M.; Menoufy, M.F.; Amhed, S.H.

    2004-01-01

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

  18. Mixed Alcohol Synthesis Catalyst Screening

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-09-03

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

  19. Management Innovation Capabilities

    DEFF Research Database (Denmark)

    Harder, Mie

    Management innovation is the implementation of a new management practice, process, technique or structure that significantly alters the way the work of management is performed. This paper presents a typology categorizing management innovation along two dimensions; radicalness and complexity. Then......, the paper proposes a model of the foundations of management innovation. Propositions and implications for future research are discussed.......Management innovation is the implementation of a new management practice, process, technique or structure that significantly alters the way the work of management is performed. This paper presents a typology categorizing management innovation along two dimensions; radicalness and complexity. Then......, the paper introduces the concept of management innovation capabilities which refers to the ability of a firm to purposefully create, extend and modify its managerial resource base to address rapidly changing environments. Drawing upon behavioral theory of the firm and the dynamic capabilities framework...

  20. Group Capability Model

    Science.gov (United States)

    Olejarski, Michael; Appleton, Amy; Deltorchio, Stephen

    2009-01-01

    The Group Capability Model (GCM) is a software tool that allows an organization, from first line management to senior executive, to monitor and track the health (capability) of various groups in performing their contractual obligations. GCM calculates a Group Capability Index (GCI) by comparing actual head counts, certifications, and/or skills within a group. The model can also be used to simulate the effects of employee usage, training, and attrition on the GCI. A universal tool and common method was required due to the high risk of losing skills necessary to complete the Space Shuttle Program and meet the needs of the Constellation Program. During this transition from one space vehicle to another, the uncertainty among the critical skilled workforce is high and attrition has the potential to be unmanageable. GCM allows managers to establish requirements for their group in the form of head counts, certification requirements, or skills requirements. GCM then calculates a Group Capability Index (GCI), where a score of 1 indicates that the group is at the appropriate level; anything less than 1 indicates a potential for improvement. This shows the health of a group, both currently and over time. GCM accepts as input head count, certification needs, critical needs, competency needs, and competency critical needs. In addition, team members are categorized by years of experience, percentage of contribution, ex-members and their skills, availability, function, and in-work requirements. Outputs are several reports, including actual vs. required head count, actual vs. required certificates, CGI change over time (by month), and more. The program stores historical data for summary and historical reporting, which is done via an Excel spreadsheet that is color-coded to show health statistics at a glance. GCM has provided the Shuttle Ground Processing team with a quantifiable, repeatable approach to assessing and managing the skills in their organization. They now have a common

  1. Accelerated deployment of nanostructured hydrotreating catalysts. Final CRADA Report.

    Energy Technology Data Exchange (ETDEWEB)

    Libera, J.A.; Snyder, S.W.; Mane, A.; Elam, J.W.; Cronauer, D.C.; Muntean, J.A.; Wu, T.; Miller, J.T. (Chemical Sciences and Engineering Division); ( ES)

    2012-08-27

    Nanomanufacturing offers an opportunity to create domestic jobs and facilitate economic growth. In response to this need, U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy issued a Research Call to develop nanomanufacturing capabilities at the National Laboratories. High performance catalysts represent a unique opportunity to deploy nanomanufacturing technologies. Re-refining of used lube oil offers an opportunity to create manufacturing jobs and decrease dependence on imported petroleum. Improved catalysts are required to produce a better quality product, decrease environmental impact, extend catalyst life, and improve overall economics of lube oil re-refining. Argonne National Laboratory (Argonne) in cooperation with Universal Lubricants, Inc. (ULI) and Chemical Engineering Partners (CEP) have carried out a Cooperative Research and Development Agreement (CRADA) to prepare nanostructured hydrotreating catalysts using atomic layer deposition (ALD) to exhibit superior performance for the re-refining of used lube oil. We investigated the upgrading of recycled lube oil by hydrogenation using commercial, synthetically-modified commercial catalysts, and synthesized catalysts. A down-flow (trickle bed) catalytic unit was used for the hydrogenation experiments. In addition to carrying out elemental analyses of the various feed and product fractions, characterization was undertaken using H{sup 1} and C{sup 13} NMR. Initially commercial were evaluated. Second these commercial catalysts were promoted with precious metals using atomic layer deposition (ALD). Performance improvements were observed that declined with catalyst aging. An alternate approach was undertaken to deeply upgrade ULI product oils. Using a synthesized catalyst, much lower hydrogenation temperatures were required than commercial catalysts. Other performance improvements were also observed. The resulting lube oil fractions were of high purity even at low reaction severity. The

  2. 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

  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. A Catalyst for Change

    DEFF Research Database (Denmark)

    Lønsmann, Dorte

    2017-01-01

    into in a process that hinges on new members functioning as tools for management to bring about the desired change. The article shows that while the newcomer is used as a catalyst for increased use of English and for the creation of a 'global mindset,' she is at the same time socialized into the existing Danish...... for changing language practices toward more English, with the ultimate aim of creating a 'global mindset' in the organization. Language socialization in a transient multilingual setting is shown to focus on and assign positive value to new linguistic norms that experienced members are socialized...

  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. Life Support Catalyst Regeneration Using Ionic Liquids and In Situ Resources

    Science.gov (United States)

    Abney, Morgan B.; Karr, Laurel; Paley, Mark S.; Donovan, David N.

    2016-01-01

    Oxygen recovery from metabolic carbon dioxide is an enabling capability for long-duration manned space flight. Complete recovery of oxygen (100%) involves the production of solid carbon. Catalytic approaches for this purpose, such as Bosch technology, have been limited in trade analyses due in part to the mass penalty for high catalyst resupply caused by carbon fouling of the iron or nickel catalyst. In an effort to mitigate this challenge, several technology approaches have been proposed. These approaches have included methods to prolong the life of the catalysts by increasing the total carbon mass loading per mass catalyst, methods for simplified catalyst introduction and removal to limit the resupply container mass, methods of using in situ resources, and methods to regenerate catalyst material. Research and development into these methods is ongoing, but only use of in situ resources and/or complete regeneration of catalyst material has the potential to entirely eliminate the need for resupply. The use of ionic liquids provides an opportunity to combine these methods in a technology approach designed to eliminate the need for resupply of oxygen recovery catalyst. Here we describe the results of an initial feasibility study using ionic liquids and in situ resources for life support catalyst regeneration, we discuss the key challenges with the approach, and we propose future efforts to advance the technology.

  7. Building Server Capabilities

    DEFF Research Database (Denmark)

    Adeyemi, Oluseyi

    2013-01-01

    Many western companies have moved part of their operations to China in order to take advantage of cheap resources and/or to gain access to a high potential market. Depending on motive, offshore facilities usually start either as “sales-only” of products exported by headquarters or “production......-only”, exporting parts and components back to headquarter for sales in the home country. In the course of time, the role of offshore subsidiaries in a company’s operations network tends to change and, with that, the capabilities, of the subsidiaries. Focusing on Danish subsidiaries in China, the objective...

  8. ISOPHOT - Capabilities and performance

    DEFF Research Database (Denmark)

    Lemke, D.; Klaas, U.; Abolins, J.

    1996-01-01

    ISOPHOT covers the largest wavelength range on ISO from 2.5 to 240 mu m. Its scientific capabilities include multi filter and multi-aperture photometry, polarimetry, imaging and spectrophotometry. All modes can optionally include a focal plane chopper. The backbone of the photometric calibration...... operating the instrument in space are continuously being implemented in the standard data reduction software packages available to every observer. Particular strengths of the instrument include the detectability of very cold sources, high resolution mapping and fast spectrophotometry. The far infrared...

  9. Catalysts for low temperature oxidation

    Science.gov (United States)

    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.

  10. Laboratory microfusion capability study

    International Nuclear Information System (INIS)

    1993-05-01

    The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy's Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options; the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase II study are described in the present report

  11. Heterogeneous base catalysts for edible palm and non-edible Jatropha-based biodiesel production.

    Science.gov (United States)

    Lee, Hwei Voon; Juan, Joon Ching; Binti Abdullah, Nurul Fitriyah; Nizah Mf, Rabiah; Taufiq-Yap, Yun Hin

    2014-01-01

    Transesterification catalyzed by solid base catalyst is a brilliant technology for the noble process featuring the fast reaction under mild reacting condition in biodiesel production. Heterogeneous base catalysts are generally more reactive than solid acid catalysts which require extreme operating condition for high conversion and biodiesel yield. In the present study, synthesis of biodiesel was studied by using edible (palm) or non-edible (Jatropha) feedstock catalyzed by heterogeneous base catalysts such as supported alkali metal (NaOH/Al2O3), alkaline-earth metal oxide (MgO, CaO and SrO) and mixed metal oxides catalysts (CaMgO and CaZnO). The chemical characteristic, textural properties, basicity profile and leaching test of synthesized catalysts were studied by using X-ray diffraction, BET measurement, TPD-CO2 and ICP-AES analysis, respectively. Transesterification activity of solid base catalysts showed that > 90% of palm biodiesel and > 80% of Jatropha biodiesel yield under 3 wt.% of catalyst, 3 h reaction time, methanol to oil ratio of 15:1 under 65°C. This indicated that other than physicochemical characteristic of catalysts; different types of natural oil greatly influence the catalytic reaction due to the presence of free fatty acids (FFAs). Among the solid base catalysts, calcium based mixed metal oxides catalysts with binary metal system (CaMgO and CaZnO) showed capability to maintain the transesterification activity for 3 continuous runs at ~ 80% yield. These catalysts render high durability characteristic in transesterification with low active metal leaching for several cycles.

  12. Ring opening metathesis polymerization catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, R.H.; Johnson, L.K.; Novak, B.M.; Hillmyer, M.; Benedicto, A.; France, M.; Nguyen, S.T. [California Institute of Technology, Pasadena, CA (United States)

    1993-12-31

    Over the past eight years, a number of new catalysts for the ring opening metathesis polymerization of cyclic olefins have been developed. These catalysts are simple organometallic complexes containing metal carbon multiple bonds that in most cases polymerize olefins by a living process. These catalysts have been used to prepare a family of near monodispersed and structurally homogeneous polymers, a series of telechelic polymers with controlled molecular weight and functionality and triblock polymers with segments with potentially interesting electronic properties. A series of new group VIII catalysts are being developed that allow a wide range of functionality to be incorporated into the polymer side chains. The same catalysts can also be used in the synthesis of fine chemicals.

  13. Supported molten-metal catalysts

    Science.gov (United States)

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

    2001-01-01

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

  14. Development of an in vivo visual robot system with a magnetic anchoring mechanism and a lens cleaning mechanism for laparoendoscopic single-site surgery (LESS).

    Science.gov (United States)

    Feng, Haibo; Dong, Dinghui; Ma, Tengfei; Zhuang, Jinlei; Fu, Yili; Lv, Yi; Li, Liyi

    2017-12-01

    Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single-site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems. In this work, an in vivo visual robot system with a new mechanism for LESS was investigated. A finite element method (FEM) analysis was carried out to ensure the safety of the in vivo visual robot during the movement, which was the most important concern for surgical purposes. A master-slave control strategy was adopted, in which the control model was established by off-line experiments. The in vivo visual robot system was verified by using a phantom box. The experiment results show that the robot system can successfully realize the expected functionalities and meet the demands of LESS. The experiment results indicate that the in vivo visual robot with high manipulability has great potential in clinical application. Copyright © 2017 John Wiley & Sons, Ltd.

  15. Laparoendoscopic single-site gastric bands versus standard multiport gastric bands: a comparison of technical learning curve measured by surgical time.

    Science.gov (United States)

    Gawart, Matthew; Dupitron, Sabine; Lutfi, Rami

    2012-03-01

    We aimed to evaluate our learning curve comparing surgical time of laparoendoscopic single-site (LESS) banding with multiport laparoscopy. We performed a retrospective analysis of prospectively collected data comparing our first 48 LESS bands with our first 50 multiport laparoscopic bands at our institution. We then compared the first 24 LESS bands with the last 24 bands. The average body mass index for the LESS group was significantly lower than for the laparoscopic group (43.19 vs 48.3; P < .0001). The surgical time was much faster toward the second half of our experience performing the LESS procedure (85.34 vs 68.8; P = .0055). LESS banding took significantly longer than our early traditional laparoscopic adjustable gastric banding (76.85 vs 64.4; P = .0015). We conclude that in experienced hands, single-incision banding is feasible and safe to perform. Long-term data are needed to prove that LESS banding is as good a surgery as traditional laparoscopic surgery. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Review and meta-analysis of prospective randomized controlled trials (RCTs) comparing laparo-endoscopic single site and multiport laparoscopy in gynecologic operative procedures.

    Science.gov (United States)

    Pontis, Alessandro; Sedda, Federica; Mereu, Liliana; Podda, Mauro; Melis, Gian Benedetto; Pisanu, Adolfo; Angioni, Stefano

    2016-09-01

    To critically appraise published randomized controlled trials (RCTs) comparing laparo-endoscopic single site (LESS) and multi-port laparoscopic (MPL) in gynecologic operative surgery; the aim was to assess feasibility, safety, and potential benefits of LESS in comparison to MPL. A systematic review and meta-analysis of eleven RCTs. Women undergoing operative LESS and MPL gynecologic procedure (hysterectomy, cystectomy, salpingectomy, salpingo-oophorectomy, myomectomy). Outcomes evaluated were as follows: postoperative overall morbidity, postoperative pain evaluation at 6, 12, 24 and 48 h, cosmetic patient satisfaction, conversion rate, body mass index (BMI), operative time, blood loss, hemoglobin drop, postoperative hospital stay. Eleven RCTs comprising 956 women with gynecologic surgical disease randomized to either LESS (477) or MPL procedures (479) were analyzed systematically. The LESS approach is a surgical procedure with longer operative and better cosmetic results time than MPL but without statistical significance. Operative outcomes, postoperative recovery, postoperative morbidity and patient satisfaction are similar in LESS and MPL. LESS may be considered an alternative to MPL with comparable feasibility and safety in gynecologic operative procedures. However, it does not offer the expected advantages in terms of postoperative pain and cosmetic satisfaction.

  17. Silica-supported (nBuCp)2ZrCl2: Effect of catalyst active center distribution on ethylene-1-hexene copolymerization

    KAUST Repository

    Atiqullah, Muhammad

    2013-08-12

    Metallocenes are a modern innovation in polyolefin catalysis research. Therefore, two supported metallocene catalysts-silica/MAO/(nBuCp)2ZrCl2 (Catalyst 1) and silica/nBuSnCl3/MAO/(nBuCp)2ZrCl2 (Catalyst 2), where MAO is methylaluminoxane-were synthesized, and subsequently used to prepare, without separate feeding of MAO, ethylene-1-hexene Copolymer 1 and Copolymer 2, respectively. Fouling-free copolymerization, catalyst kinetic stability and production of free-flowing polymer particles (replicating the catalyst particle size distribution) confirmed the occurrence of heterogeneous catalysis. The catalyst active center distribution was modeled by deconvoluting the measured molecular weight distribution and copolymer composition distribution. Five different active center types were predicted for each catalyst, which was corroborated by successive self-nucleation and annealing experiments, as well as by an extended X-ray absorption fine structure spectroscopy report published in the literature. Hence, metallocenes impregnated particularly on an MAO-pretreated support may be rightly envisioned to comprise an ensemble of isolated single sites that have varying coordination environments. This study shows how the active center distribution and the design of supported MAO anions affect copolymerization activity, polymerization mechanism and the resulting polymer microstructures. Catalyst 2 showed less copolymerization activity than Catalyst 1. Strong chain transfer and positive co-monomer effect-both by 1-hexene-were common. Each copolymer demonstrated vinyl, vinylidene and trans-vinylene end groups, and compositional heterogeneity. All these findings were explained, as appropriate, considering the modeled active center distribution, MAO cage structure repeat units, proposed catalyst surface chemistry, segregation effects and the literature that concerns and supports this study. While doing so, new insights were obtained. Additionally, future research, along the direction

  18. Development of a Catalyst/Sorbent for Methane Reforming

    Energy Technology Data Exchange (ETDEWEB)

    B.H. Shans; T.D. Wheelock; Justinus Satrio; Karl Albrecht; Tanya Harris Janine Keeley; Ben Silva; Aaron Shell; Molly Lohry; Zachary Beversdorf

    2008-12-31

    This project led to the further development of a combined catalyst and sorbent for improving the process technology required for converting CH{sub 4} and/or CO into H{sub 2} while simultaneously separating the CO{sub 2} byproduct all in a single step. The new material is in the form of core-in-shell pellets such that each pellet consists of a CaO core surrounded by an alumina-based shell capable of supporting a Ni catalyst. The Ni is capable of catalyzing the reactions of steam with CH{sub 4} or CO to produce H{sub 2} and CO{sub 2}, whereas the CaO is capable of absorbing the CO{sub 2} as it is produced. The absorption of CO{sub 2} eliminates the reaction inhibiting effects of CO{sub 2} and provides a means for recovering the CO{sub 2} in a useful form. The present work showed that the lifecycle performance of the sorbent can be improved either by incorporating a specific amount of MgO in the material or by calcining CaO derived from limestone at 1100 C for an extended period. It also showed how to prepare a strong shell material with a large surface area required for supporting an active Ni catalyst. The method combines graded particles of {alpha}-alumina with noncrystalline alumina having a large specific surface area together with a strength promoting additive followed by controlled calcination. Two different additives produced good results: 3 {micro}m limestone and lanthanum nitrate which were converted to their respective oxides upon calcination. The oxides partially reacted with the alumina to form aluminates which probably accounted for the strength enhancing properties of the additives. The use of lanthanum made it possible to calcine the shell material at a lower temperature, which was less detrimental to the surface area, but still capable of producing a strong shell. Core-in-shell pellets made with the improved shell materials and impregnated with a Ni catalyst were used for steam reforming CH{sub 4} at different temperatures and pressures. Under all

  19. Standard method for total molybdenum in fresh alumina-base catalysts

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This test method covers the determination of molybdenum in alumina-base catalyst and has been cooperatively tested at molybdenum concentrations from 8 to 18 weight %, expressed as MoO 3 . Any component of the catalyst other than molybdenum such as iron, tungsten, etc., which is capable of being oxidized by either ferric or ceric ions after being passed through a zinc-amalgam reductor column (Jones reductor) will interfere. This standard may involve hazardous, materials, operations, and equipment

  20. Development of GREET Catalyst Module

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhichao [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division; Cronauer, Donald C. [Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

    2014-09-01

    Catalysts are critical inputs for many pathways that convert biomass into biofuels. Energy consumption and greenhouse gas (GHG) emissions during the production of catalysts and chemical inputs influence the life-cycle energy consumption, and GHG emissions of biofuels and need to be considered in biofuel life-cycle analysis (LCA). In this report, we develop energy and material flows for the production of three different catalysts (tar reforming, alcohol synthesis, Zeolite Socony Mobil-5 [ZSM-5]) 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. They were selected because they are consumed in existing U.S. Department of Energy (DOE) analyses of biofuel processes. For example, a thermochemical ethanol production pathway (indirect gasification and mixed alcohol synthesis) developed by the National Renewable Energy Laboratory (NREL) uses olivine, DEPG, and tar reforming and alcohol synthesis catalysts (Dutta et al., 2011). ZSM-5 can be used in biofuel production pathways such as catalytic upgrading of sugars into hydrocarbons (Biddy and Jones, 2013). Other uses for these compounds and catalysts are certainly possible. In this report, we document the data sources and methodology we used to develop material and energy flows for the catalysts and compounds in the GREET catalyst module. In Section 2 we focus on compounds used in the model Dutta et al. (2011) developed. In Section 3, we report material and energy flows associated with ZSM-5 production. Finally, in Section 4, we report results.

  1. Performance of (CoPC)n catalyst in active lithium-thionyl chloride cells

    Science.gov (United States)

    Shah, Pinakin M.

    1990-01-01

    An experimental study was conducted with anode limited D size cells to characterize the performance of an active lithium-thionyl chloride (Li/SOCl2) system using the polymeric cobalt phthalocyanine, (CoPC)n, catalyst in carbon cathodes. The author describes the results of this experiment with respect to initial voltage delays, operating voltages, and capacities. The effectiveness of the preconditioning methods evolved to alleviate passivation effects on storage are also discussed. The results clearly demonstrated the superior high rate capability of cells with the catalyst. The catalyst did not adversely impact the performance of cells after active storage for up to 6 months, while retaining its beneficial influences.

  2. Chalcogen catalysts for polymer electrolyte fuel cell

    Science.gov (United States)

    Alonso-Vante, Nicolas [Buxerolles, FR; Zelenay, Piotr [Los Alamos, NM; Choi, Jong-Ho [Los Alamos, NM; Wieckowski, Andrzej [Champaign, IL; Cao, Dianxue [Urbana, IL

    2009-09-15

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

  3. Increasing the lifetime of fuel cell catalysts

    NARCIS (Netherlands)

    Latsuzbaia, R.

    2015-01-01

    In this thesis, I discuss a novel idea of fuel cell catalyst regeneration to increase lifetime of the PEM fuel cell electrode/catalyst operation and, therefore, reduce the catalyst costs. As many of the catalyst degradation mechanisms are difficult to avoid, the regeneration is alternative option to

  4. 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.

  5. Aircraft Capability Management

    Science.gov (United States)

    Mumaw, Randy; Feary, Mike

    2018-01-01

    This presentation presents an overview of work performed at NASA Ames Research Center in 2017. The work concerns the analysis of current aircraft system management displays, and the initial development of an interface for providing information about aircraft system status. The new interface proposes a shift away from current aircraft system alerting interfaces that report the status of physical components, and towards displaying the implications of degradations on mission capability. The proposed interface describes these component failures in terms of operational consequences of aircraft system degradations. The research activity was an effort to examine the utility of different representations of complex systems and operating environments to support real-time decision making of off-nominal situations. A specific focus was to develop representations that provide better integrated information to allow pilots to more easily reason about the operational consequences of the off-nominal situations. The work is also seen as a pathway to autonomy, as information is integrated and understood in a form that automated responses could be developed for the off-nominal situations in the future.

  6. Mobile systems capability plan

    International Nuclear Information System (INIS)

    1996-09-01

    This plan was prepared to initiate contracting for and deployment of these mobile system services. 102,000 cubic meters of retrievable, contact-handled TRU waste are stored at many sites around the country. Also, an estimated 38,000 cubic meters of TRU waste will be generated in the course of waste inventory workoff and continuing DOE operations. All the defense TRU waste is destined for disposal in WIPP near Carlsbad NM. To ship TRU waste there, sites must first certify that the waste meets WIPP waste acceptance criteria. The waste must be characterized, and if not acceptable, subjected to additional processing, including repackaging. Most sites plan to use existing fixed facilities or open new ones between FY1997-2006 to perform these functions; small-quantity sites lack this capability. An alternative to fixed facilities is the use of mobile systems mounted in trailers or skids, and transported to sites. Mobile systems will be used for all characterization and certification at small sites; large sites can also use them. The Carlsbad Area Office plans to pursue a strategy of privatization of mobile system services, since this offers a number of advantages. To indicate the possible magnitude of the costs of deploying mobile systems, preliminary estimates of equipment, maintenance, and operating costs over a 10-year period were prepared and options for purchase, lease, and privatization through fixed-price contracts considered

  7. Totally Transanal Laparo-Endoscopic Single-Site ProctoColectomy-Ileoanal J-Pouch (TLPC-J: An Experimental Study of a Novel Approach

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Vahdad

    2015-09-01

    Full Text Available Background: The natural orifice transluminal endoscopic surgery (NOTES has become a commonly considered novel approach in the surgical field. The NOTES provide possibility of operation through the natural orifice and decreases the intentional puncture of the systemic organ and subsequent complications. Totally transanal laparo-endoscopic single-site proctoColectomy-Ileoanal J-Pouch (TLPC-J is a novel method in minimally invasive surgery for total colectomy. The main goal of this study is to perform this new method on an animal model, to assess probable complication and to resolve probable issues by using patients that are candidate for total colectomy. Method: Five dogs were prepared in lithotomy position. The TLPC-I procedure consists of endorectal technique with full thickness rectal dissection starting 1 cm orally from the dentate line above the peritoneal reflection and the proximal bowel was replaced into the abdominal cavity. Afterwards, the TriPort system was inserted in the anal canal and mesentrial resection of the total colon, mobilization of a distal ileal segment and intracorporeal suture of an ileal J-loop was accomplished by this system. An incision in the J-loop was conducted transanally. The J-pouch was created with an Endo-GIA® and sutured to the rectal wall. Results: All animals survived and passed stool with clear post operation situation. There was no infection in site of anastomosis. Conclusion: The TLPC-I provides the possibility of surgery without abdominal wall incision and decreases post operation complication such as pain, abdominal wound infection and wound dehiscence. This technique increases the quality of life and surgeons can discharge the patients early.

  8. The Decline of Laparoendoscopic Single-Site Surgery: A Survey of the Endourological Society to Identify Shortcomings and Guidance for Future Directions.

    Science.gov (United States)

    Sorokin, Igor; Canvasser, Noah E; Irwin, Brian; Autorino, Riccardo; Liatsikos, Evangelos N; Cadeddu, Jeffrey A; Rane, Abhay

    2017-10-01

    To analyze the most recent temporal trends in the adoption of urologic laparoendoscopic single-site (LESS), to identify the perceived limitations associated with its decline, and to determine factors that might revive the role of LESS in the field of minimally invasive urologic surgery. A 15 question survey was created and sent to members of the Endourological Society in September 2016. Only members who performed LESS procedures in practice were asked to respond. In total, 106 urologists responded to the survey. Most of the respondents were from the United States (35%) and worked in an academic hospital (84.9%). Standard LESS was the most popular approach (78.1%), while 14.3% used robotics, and 7.6% used both. 2009 marked the most popular year to perform the initial (27.6%) and the majority (20%) of LESS procedures. The most common LESS procedure was a radical/simple nephrectomy (51%) followed by pyeloplasty (17.3%). In the past 12 months, 60% of respondents had performed no LESS procedures. Compared to conventional laparoscopy, respondents only believed cosmesis to be better, however, this enthusiasm waned over time. Worsening shifts in enthusiasm for LESS also occurred with patient desire, marketability, cost, safety, and robotic adaptability. The highest rated factor to help LESS regain popularity was a new robotic platform. The decline of LESS is apparent, with few urologists continuing to perform procedures attributed to multiple factors. The availability of a purpose-built robotic platform and better instrumentation might translate into a renewed future interest of LESS.

  9. An evaluation of single-site statistical downscaling techniques in terms of indices of climate extremes for the Midwest of Iran

    Science.gov (United States)

    Farajzadeh, M.; Oji, R.; Cannon, A. J.; Ghavidel, Y.; Massah Bavani, A.

    2015-04-01

    Seven single-site statistical downscaling methods for daily temperature and precipitation, including four deterministic algorithms [analog model (ANM), quantile mapping with delta method extrapolation (QMD), cumulative distribution function transform (CDFt), and model-based recursive partitioning (MOB)] and three stochastic algorithms [generalized linear model (GLM), Conditional Density Estimation Network Creation and Evaluation (CaDENCE), and Statistical Downscaling Model-Decision Centric (SDSM-DC] are evaluated at nine stations located in the mountainous region of Iran's Midwest. The methods are of widely varying complexity, with input requirements that range from single-point predictors of temperature and precipitation to multivariate synoptic-scale fields. The period 1981-2000 is used for model calibration and 2001-2010 for validation, with performance assessed in terms of 27 Climate Extremes Indices (CLIMDEX). The sensitivity of the methods to large-scale anomalies and their ability to replicate the observed data distribution in the validation period are separately tested for each index by Pearson correlation and Kolmogorov-Smirnov (KS) tests, respectively. Combined tests are used to assess overall model performances. MOB performed best, passing 14.5 % (49.6 %) of the combined (single) tests, respectively, followed by SDSM, CaDENCE, and GLM [14.5 % (46.5 %), 13.2 % (47.1 %), and 12.8 % (43.2 %), respectively], and then by QMD, CDFt, and ANM [7 % (45.7 %), 4.9 % (45.3 %), and 1.6 % (37.9 %), respectively]. Correlation tests were passed less frequently than KS tests. All methods downscaled temperature indices better than precipitation indices. Some indices, notably R20, R25, SDII, CWD, and TNx, were not successfully simulated by any of the methods. Model performance varied widely across the study region.

  10. Six-month visual outcomes for the correction of presbyopia using a small-aperture corneal inlay: single-site experience

    Science.gov (United States)

    Moshirfar, Majid; Quist, Tyler S; Skanchy, David F; Wallace, Ryan T; Linn, Steven H; Hoopes, Phillip C

    2016-01-01

    Objective The objective of this study was to describe 6-month postoperative efficacy and safety outcomes after monocular KAMRA corneal inlay implantation in emmetropic presbyopic patients. Study design This study followed a retrospective chart analysis. Setting This study was performed at Hoopes Vision in Draper, UT, USA. Subjects and methods Fifty-seven patients met the inclusion criteria of this study and underwent KAMRA corneal inlay implantation following the approval of the United States Food and Drug Association between May 2015 and April 2016 at a single site. Surgery involved femtosecond laser-created corneal pockets of various depths. Efficacy, safety, and patient satisfaction reports were analyzed at 3 and 6 months. Results At 6 months follow-up, the monocular uncorrected near visual acuity (UNVA) was Jaeger (J) 4 (20/32), the mean uncorrected distance visual acuity was 20/25, and the mean corrected distance visual acuity was 20/20. At 6 months, 71% of patients with a pocket depth of ≥250 μm had a UNVA of 20/20 or better, whereas only 22% of patients with a shallow pocket depth of inlay recentration, all of which resulted in improved visual acuity. At 6 months, 72% of patients reported some level of satisfaction, 26% of patients reported being “not dependent” on reading glasses, and 62% of patients reported being able to do most things in bright light without reading glasses. Conclusion For patients with emmetropic presbyopia, the KAMRA inlay is a viable treatment option resulting in improved UNVA. Increased pocket depth may be associated with better postoperative outcomes. Safety rates are high, while explantation and recentering rates are low. Overall, patient satisfaction of the KAMRA inlay is good. PMID:27843289

  11. Robotic Single-Site and Conventional Laparoscopic Surgery in Gynecology: Clinical Outcomes and Cost Analysis of a Matched Case-Control Study.

    Science.gov (United States)

    El Hachem, Lena; Andikyan, Vaagn; Mathews, Shyama; Friedman, Kathryn; Poeran, Jashvant; Shieh, Kenneth; Geoghegan, Michael; Gretz, Herbert F

    2016-01-01

    To assess the clinical outcomes and costs associated with robotic single-site (RSS) surgery compared with those of conventional laparoscopy (CL) in gynecology. Retrospective case-control study (Canadian Task Force classification II-2). University-affiliated community hospital. Female patients undergoing RSS or CL gynecologic procedures. Comparison of consecutive RSS gynecologic procedures (cases) undertaken between October 2013 and March 2014 with matched CL procedures (controls) completed during the same time period by the same surgeon. Patient demographic data, operative data, and hospital financial data were abstracted from the electronic charts and financial systems. An incremental cost analysis based on the use of disposable equipment was performed. Total hospital charges were determined for matched RSS cases vs CL cases. RSS surgery was completed in 25 out of 33 attempts; 3 cases were aborted before docking, and 5 were converted to a multisite surgery. There were no intraoperative complications or conversions to laparotomy. The completed cases included 11 adnexal cases and 14 hysterectomies, 3 of which included pelvic lymph node dissection. Compared with the CL group, total operative times were higher in the RSS group; however, there were no significant between-group differences in estimated blood loss, length of hospital stay, or complication rates. Disposable equipment cost per case, direct costs, and total hospital charges were evaluated. RSS was associated with an increased disposable cost per case of $248 to $378, depending on the method used for vaginal cuff closure. The average total hospital charges for matched outpatient adnexal surgery were $15,450 for the CL controls and $18,585 for the RSS cases (p total hospital charges for matched outpatient benign hysterectomy were $14,623 for the CL controls and $21,412 for the RSS cases (p cost per case and total hospital charges. Careful case selection and judicious use of equipment are necessary to

  12. Laparoendoscopic single-site surgery with hysterectomy in patients with prior cesarean section: comparison of surgical outcomes with bladder dissection techniques.

    Science.gov (United States)

    Jo, Eun Ju; Kim, Tae-Joong; Lee, Yoo-Young; Choi, Chel Hun; Lee, Jeong-Won; Bae, Duk-Soo; Kim, Byoung-Gie

    2013-01-01

    The aim of this study was to compare operative outcomes from 300 patients who underwent laparoendoscopic single-site surgery (LESS) with hysterectomy (H) according to previous cesarean section and to describe the bladder dissection technique in detail. Retrospective cohort study (Canadian task classification II-2). A university hospital, research hospital, and a tertiary care center. In total, 300 LESS-H procedures were performed for benign gynecologic disease, cervical disease, and endometrial disease at Samsung Medical Center in Seoul, Korea, between May 2008 and February 2012. Patients were categorized into 2 groups according to previous cesarean history: the previous cesarean section group (n = 98) and the no history of previous cesarean section group (n = 202). LESS-H with vaginal or lateral approach for bladder dissection. Baseline demographics and clinical characteristics, except for age, were generally the same between the 2 groups. The operative outcomes including operative time, uterine weight, estimated blood loss, hemoglobin change, hospital stay, and transfusion rate were not different between the 2 groups. Adhesiolysis was required more in the previous cesarean section group (p = .002). LESS failure requiring additional trocars occurred more often in the previous cesarean section group (p = .041), but the rates of conversion to laparotomy were not different (p = .327). The overall surgical complication rate except transfusion was 2.67% in this study. Two cases of urologic problems with ureter injury or bladder injury were reported in the previous cesarean section group. In the no previous cesarean section group, there were 2 urologic problems. LESS-H is a feasible procedure with a lateral approach or vaginal approach for bladder dissection, even in patients with previous cesarean section. Copyright © 2013 AAGL. Published by Elsevier Inc. All rights reserved.

  13. Hybrid laparoendoscopic single-site surgery of upper urinary tract with the use of mini-laparoscopic instruments: cosmetic outcome and midterm oncological outcome.

    Science.gov (United States)

    Kallidonis, Panagiotis; Kyriazis, Jason; Kamal, Wissam; Porpiglia, Francesco; Liatsikos, Evangelos

    2016-09-01

    To evaluate the efficacy of mini-laparoscopic instruments in combination with laparoendoscopic single-site surgery (LESS) instruments for the performance of oncological urological surgery. Thirty-five patients underwent oncological hybrid LESS either mini-laparoscopic-assisted LESS partial nephrectomy (LESS-PN, n = 12) or mini-laparoscopic-assisted LESS radical nephrectomy (LESS-RN, n = 23). Perioperative data were prospectively collected. The patient and observer scar assessment scale (POSAS) was used for the evaluation of the cosmetic outcome. Mean tumor size treated by LESS-PNs was 28.8 (IQR 20.5-37.3) mm. Average operative time and blood loss were 123 (IQR 112.5-145) min and 158.3 (IQR 100-200) ml, respectively. Renal artery clamping took place in seven cases. LESS-RN was performed in cases with a mean tumor size of 60 (IQR 48-71.5) mm. The average operative time was 116.8 (IQR 100-130) min. Average blood loss was 137 (IQR 100-150) ml. Complications were limited to grade II according to Clavien classification. The oncological outcome, including midterm results, was directly comparable to the literature. Patients reported low pain scores and high satisfaction in terms of postoperative scarring. The POSAS scores confirmed the excellent cosmetic outcome of hybrid LESS. The combination of mini-laparoscopic and LESS instrumentation as routine equipment of oncological surgery provided an efficient option for urologic surgery. The combination of mini-laparoscopic and LESS instruments improves the intraoperative ergonomics of LESS-PN and LESS-RN. The provided surgical and oncological outcome compares favorably to the LESS and conventional laparoscopic literature.

  14. Laparo-Endoscopic Single-Site Surgery for Radical and Cytoreductive Nephrectomy, Renal Vein Thrombectomy, and Partial Nephrectomy: A Prospective Pilot Evaluation

    Directory of Open Access Journals (Sweden)

    Ithaar H. Derweesh

    2010-01-01

    Full Text Available Introduction. Laparo-endoscopic single-site surgery (LESS may diminish morbidity of laparoscopic surgery. We prospectively evaluated feasibility and outcomes of LESS-Radical Nephrectomy (LESS-RN and Partial Nephrectomy (LESS-PN. Methods. 10 patients underwent LESS-RN (6 and LESS-PN (4 between 2/2009-5/2009. LESS-RN included 2 with renal vein thrombectomy, one of which was also cytoreductive. Transperitoneal LESS access was obtained by periumbilical incision. Patient/tumor characteristics, oncologic, and quality of life (QoL outcomes were analyzed. Results. 3 Men/7 Women (mean age 58.7 years, median follow-up 9.8 months underwent LESS. 9/10 cases were completed successfully. All had negative margins. Mean operative time was 161 minutes, estimated blood loss was 125 mL, and incision size was 4.4 cm. Median tumor size for LESS-RN and -PN was 5.0 and 1.7 cm (=.045. Median LESS-PN ischemia time was 24 minutes; mean preoperative/postoperative creatinine were 0.7/0.8 mg/dL (=.19. Mean pain score at discharge was 1.3. Mean preoperative, 3-, and 6-month postoperative SF-36 QoL Score was 73.8, 74.4 and 77.1 (=.222. All patients are currently alive. Conclusions. LESS-RN, renal vein thrombectomy, and PN are technically feasible and safe while maintaining adherence to oncologic principles, with excellent QoL preservation and low discharge pain scores. Further study is requisite.

  15. Single-site laparoscopic percutaneous extraperitoneal closure of the internal ring using an epidural and spinal needle: excellent results in 1464 children with inguinal hernia/hydrocele.

    Science.gov (United States)

    Wang, Furan; Zhong, Hongji; Chen, Yi; Zhao, Junfeng; Li, Yan; Chen, Junxian; Dong, Sheng

    2017-07-01

    Laparoscopic percutaneous extraperitoneal closure (LPEC) of the internal ring is a well-developed procedure for pediatric inguinal hernia and hydrocele. To reduce the skin incisions and improve the cosmesis, single-site LPEC (SLPEC) has been developed with numerous techniques and instruments. In this study, we described our modifications of SLPEC using an epidural and spinal needle in a large pediatric population. From February 2013 to February 2016, 1464 pediatric patients who underwent SLPEC in our hospital were retrospectively reviewed. A 5-mm laparoscope was introduced at the subumbilicus. An 18-gauge epidural needle with a silk suture loop was introduced into the corresponding skin of the internal ring. The needle was advanced extraperitoneally on the medial side of the ring. The suture loop was pushed into peritoneal cavity by the spinal needle. The epidural needle was withdrawn to the roof of the internal ring and then kept advancing along the lateral side. Aided by the spinal needle and laparoscope, a long suture loop was sent into the first loop in peritoneal cavity. The long suture loop was pulled out of the abdominal wall by picking up the first loop, and the internal ring was closed by knotting the suture extracorporeally. The contralateral patent processus vaginalis (CPPV) was simultaneously repaired if present. In total, 981 patients presented with inguinal hernia and 483 with hydrocele. A CPPV was present in 483 patients with unilateral pathology and thus simultaneously repaired. The hydrodissection technique and grasping forceps were used in 290 and 113 patients, respectively. The median operation time was 11 min (7-18 min) and 18 min (10-30 min) for unilateral and bilateral inguinal hernias/hydroceles, respectively. There was no development of intra- or postoperative complications. SLPEC using an epidural and spinal needle can be performed with excellent results in pediatric inguinal hernias and hydroceles.

  16. Technology development for iron F-T catalysts. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Frame, R.R.; Gala, H.B.

    1994-08-01

    The objectives of this work were twofold. The first objective was to design and construct a pilot plant for preparing precipitated iron oxide F-T precursors and demonstrate that the rate of production from this plant is equivalent to 100 lbs/day of dried metal oxide. Secondly, these precipitates were to be used to prepare catalysts capable of achieving 88% CO + H{sub 2} conversion with {le} 5 mole percent selectivity to methane + ethane.

  17. Impact of Personnel Capabilities on Organizational Innovation Capability

    DEFF Research Database (Denmark)

    Nielsen, Susanne Balslev; Momeni, Mostafa

    2016-01-01

    One of the most dynamic capabilities that lead to the strongest competitive advantage in the organizations is the innovation capability. Analysing the development of a firm’s innovation capability is an important research project, and can help organizations to achieve competitive advantage in thi...

  18. Small rover exploration capabilities

    Science.gov (United States)

    Salotti, Jean-Marc; Laithier, Corentin; Machut, Benoit; Marie, Aurélien; Bruneau, Audrey; Grömer, Gernot; Foing, Bernard H.

    2015-05-01

    For a human mission to the Moon or Mars, an important question is to determine the best strategy for the choice of surface vehicles. Recent studies suggest that the first missions to Mars will be strongly constrained and that only small unpressurized vehicles will be available. We analyze the exploration capabilities and limitations of small surface vehicles from the user perspective. Following the “human centered design” paradigm, the team focused on human systems interactions and conducted the following experiments: - Another member of our team participated in the ILEWG EuroMoonMars 2013 simulation at the Mars Desert Research Station in Utah during the same period of time. Although the possible traverses were restricted, a similar study with analog space suits and quads has been carried out. - Other experiments have been conducted in an old rock quarry close to Bordeaux, France. An expert in the use of quads for all types of terrains performed a demonstration and helped us to characterize the difficulties, the risks and advantages and drawbacks of different vehicles and tools. The vehicles that will be used on the surface of Mars have not been defined yet. Nevertheless, the results of our project already show that using a light and unpressurized vehicle (in the order of 150 kg) for the mobility on the Martian surface can be a true advantage. Part of the study was dedicated to the search for appropriate tools that could be used to make the vehicles easier to handle, safer to use and more efficient in the field to cross an obstacle. The final recommendation is to use winches and ramps, which already are widely used by quad drivers. We report on the extension of the reachable areas if such tools were available. This work has been supported by ILEWG, EuroMoonMars and the Austrian Space Forum (OEWF).

  19. Rare earth metals for automotive exhaust catalysts

    International Nuclear Information System (INIS)

    Shinjoh, Hirohumi

    2006-01-01

    The usage of rare earth metals for automotive exhaust catalysts is demonstrated in this paper. Rare earth metals have been widely used in automotive catalysts. In particular, three-way catalysts require the use of ceria compounds as oxygen storage materials, and lanthana as both a stabilizer of alumina and a promoter. The application for diesel catalysts is also illustrated. Effects of inclusion of rare earth metals in automotive catalysts are discussed

  20. Biomass processing over gold catalysts

    CERN Document Server

    Simakova, Olga A; Murzin, Dmitry Yu

    2014-01-01

    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 derived from cellulose, hemicelluloses, and woody biomass extractives. Since gold catalysts possess high stability under oxidative conditions, selective oxidation reactions were discussed more thoroughly than other critical reactions such as partial hydrogenation, acetalization, and isomerization. The influence of reaction conditions, the role of the catalyst, and the advantages and disadvantages of using gold are pre...

  1. Sandia Laboratories technical capabilities. Auxiliary capabilities: environmental health information science

    International Nuclear Information System (INIS)

    1975-09-01

    Sandia Laboratories is an engineering laboratory in which research, development, testing, and evaluation capabilities are integrated by program management for the generation of advanced designs. In fulfilling its primary responsibility to ERDA, Sandia Laboratories has acquired extensive research and development capabilities. The purpose of this series of documents is to catalog the many technical capabilities of the Laboratories. After the listing of capabilities, supporting information is provided in the form of highlights, which show applications. This document deals with auxiliary capabilities, in particular, environmental health and information science. (11 figures, 1 table) (RWR)

  2. Single Site Silica Supported Tetramethyl Niobium by the SOMC Strategy: Synthesis, Characterization and Structure-Activity Relationship in Ethylene Oligomerization Reaction

    KAUST Repository

    Hamieh, Ali Imad Ali

    2017-06-06

    Silica supported Tetramethyl niobium complex [(≡SiO)NbMe4] 2 has been isolated by surface alkylation of [(≡SiO-)NbCl3Me] 1 with dimethyl zinc in pentane. 1 can be easily synthesized by grafting of NbCl3Me2 on to the surface of partially dehydroxylated silica by the SOMC strategy. Precise structural analysis was carried out by the FTIR, advance solid state NMR, elemental analysis and mass balance techniques (gas quantification after treating 2 with degassed water) . Complex 1 was found to be active in the ethylene oligomerization to produce up to C30, whereas to our surprise complex 2 selectively dimerizes ethylene into 1-butene in the absence of a co-catalyst at the same conversion levels.

  3. Single site silica supported tetramethyl niobium by the SOMC strategy: synthesis, characterization and structure-activity relationship in the ethylene oligomerization reaction.

    Science.gov (United States)

    Hamieh, Ali; Dey, Raju; Nekoueishahraki, Bijan; Samantaray, Manoja K; Chen, Yin; Abou-Hamad, Edy; Basset, Jean-Marie

    2017-06-27

    A silica supported tetramethyl niobium complex [([triple bond, length as m-dash]SiO)NbMe 4 ] 2 has been isolated by the surface alkylation of [([triple bond, length as m-dash]SiO-)NbCl 3 Me] 1 with dimethyl zinc in pentane. 1 can be easily synthesized by grafting NbCl 3 Me 2 onto the surface of partially dehydroxylated silica by the SOMC strategy. Precise structural analysis was carried out using FTIR, advanced solid state NMR, elemental analysis and mass balance techniques (gas quantification after treating 2 with degassed water). Complex 1 was found to be active in the ethylene oligomerization reaction, producing up to C 30 , whereas to our surprise complex 2 selectively dimerized ethylene into 1-butene in the absence of a co-catalyst at the same conversion level.

  4. Structural Capability of an Organization toward Innovation Capability

    DEFF Research Database (Denmark)

    Nielsen, Susanne Balslev; Momeni, Mostafa

    2016-01-01

    competitive advantage in the organizations is the innovation capability. The innovation capability is associated with other organizational capabilities, and many organizations have focused on the need to identify innovation capabilities.This research focuses on recognition of the structural aspect......The scholars in the field of strategic management have developed two major approaches for attainment of competitive advantage: an approach based on environmental opportunities, and another one based on internal capabilities of an organization. Some investigations in the last two decades have...... indicated that the advantages relying on the internal capabilities of organizations may determine the competitive position of organizations better than environmental opportunities do. Characteristics of firms shows that one of the most internal capabilities that lead the organizations to the strongest...

  5. Octahedral molecular sieve sorbents and catalysts

    Science.gov (United States)

    Li, Liyu [Richland, WA; King, David L [Richland, WA

    2010-04-20

    Octahedral molecular sieve sorbents and catalysts are disclosed, including silver hollandite and cryptomelane. These materials can be used, for example, to catalyze the oxidation of CO.sub.x (e.g., CO), NO.sub.x (e.g., NO), hydrocarbons (e.g., C.sub.3H.sub.6) and/or sulfur-containing compounds. The disclosed materials also may be used to catalyze other reactions, such as the reduction of NO.sub.2. In some cases, the disclosed materials are capable of sorbing certain products from the reactions they catalyze. Silver hollandite, in particular, can be used to remove a substantial portion of certain sulfur-containing compounds from a gas or liquid by catalysis and/or sorption. The gas or liquid can be, for example, natural gas or a liquid hydrocarbon.

  6. The development of capability indicators

    NARCIS (Netherlands)

    Anand, Paul; Hunter, Graham; Carter, Ian; Dowding, Keith; Guala, Francesco; Van Hees, Martin

    2009-01-01

    This paper is motivated by sustained interest in the capabilities approach to welfare economics combined with the paucity of economic statistics that measure capabilities at the individual level. Specifically, it takes a much discussed account of the normatively desirable capabilities constitutive

  7. The Capability to Hold Property

    NARCIS (Netherlands)

    Claassen, Rutger

    2015-01-01

    This paper discusses the question of whether a capability theory of justice (such as that of Martha Nussbaum) should accept a basic “capability to hold property.” Answering this question is vital for bridging the gap between abstract capability theories of justice and their institutional

  8. Synthesis, Characterizations, and Applications of Metal-Ions Incorporated High Quality MCM-41 Catalysts

    International Nuclear Information System (INIS)

    Lim, Steven S.; Haller, Gary L.

    2013-01-01

    Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically V 5+ , Co 2+ , and Ni 2+ -incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated

  9. 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.

  10. Minilaparoscopic radical hysterectomy (mLPS-RH) vs laparoendoscopic single-site radical hysterectomy (LESS-RH) in early stage cervical cancer: a multicenter retrospective study.

    Science.gov (United States)

    Fagotti, Anna; Ghezzi, Fabio; Boruta, David M; Scambia, Giovanni; Escobar, Pedro; Fader, Amanda N; Malzoni, Mario; Fanfani, Francesco

    2014-01-01

    To compare the perioperative outcomes of laparoendoscopic single-site radical hysterectomy (LESS-RH) and minilaparoscopic radical hysterectomy (mLPS-RH). Retrospective study (Canadian Task Force classification II-2). Seven institutions in Italy. Forty-six patents with early cervical cancer (FIGO stage IA2-IB1/IIA1) were included in the study. Nineteen patients (41.3%) underwent LESS-RH, and 27 (58.7%) underwent mLPS-RH. Pelvic lymph node dissection was performed in all patients. In the LESS-RH group, all surgical procedures were performed through a single umbilical multichannel port. In the mLPS-RH group, the procedure was completed using a 5-mm umbilical optical trocar and 3 additional 3-mm ancillary trocars, placed suprapubically and in the left and right lower abdominal regions. There was no difference in clinicopathologic characteristics at the time of diagnosis between the LESS-RH and mLPS-RH groups. Median operative time was 270 minutes (range, 149-380 minutes) for LESS-RH, and was 180 minutes (range, 90-240 minutes) for mLPS-RH (p = .001). No further differences were detected between the 2 groups insofar as type of radical hysterectomy, number of lymph nodes removed, or perioperative outcomes. In the LESS-RH group, conversion to laparotomy was necessary in 1 patient (5.3%) because of external iliac vein injury, and in another patient, conversion to standard laparoscopy was required because of truncal obesity. In the mLPS-RH group, no conversions were observed; however, a repeat operation was performed to repair a ureteral injury. The percentage of patients discharged 1 day after surgery was significantly higher in the LESS-RH group (57.9%) compared with the mLPS-RH group (25.0%) (p = .03). After a median follow-up of 27 months (range, 9-73 months), only 1 patient, who had undergone mLPS-RH, experienced pelvic recurrence and died of the disease. Both LESS-RH and mLPS-RH are feasible ultra-minimally invasive approaches for performance of radical hysterectomy

  11. A systematic review and meta-analysis concerning single-site laparoscopic percutaneous extraperitoneal closure for pediatric inguinal hernia and hydrocele.

    Science.gov (United States)

    Chen, Yi; Wang, Furan; Zhong, Hongji; Zhao, Junfeng; Li, Yan; Shi, Zhan

    2017-12-01

    Single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac/processus vaginalis has been widely performed for repair of inguinal hernia/hydrocele in children. However, a variety of surgical instruments and techniques were used, and significant differences existed among the SLPEC reports. A literature search was performed for all available studies concerning SLPEC for pediatric inguinal hernia/hydrocele in PubMed, Embase and Cochrane library. The surgical details and operative outcomes were pooled and analyzed with software StataSE 12.0. 49 studies fulfilled the predefined inclusion criteria of this review and 37 studies were finally included in the meta-analysis. The mean incidence of CPPV was 29.1% (range 5.73-43.0%). The average of mean operative time was 19.56 min (range 8.30-41.19 min) for unilateral SLPEC and 27.23 min (range 12.80-48.19 min) for bilateral SLPEC. The total incidence of injury, conversion, recurrence, hydrocele formation, knot reaction, severe pain, and scrotal swelling was 0.32% (range 0-3.24%), 0.05% (range 0-0.89%), 0.70% (range 0-15.5%), 0.23% (range 0-3.57%), 0.33% (range 0-3.33%), 0.05% (range 0-4.55%), and 0.03% (range 0-1.52%), respectively. There was no development of testicular atrophy. Subgroup analyses showed an inverse correlation between the injury incidence and adoption of assisted forceps, hydrodissection, and blunt puncture device, between the conversion rate and adoption of hydrodissection, between the recurrence/hydrocele incidence and adoption of assisted forceps, hydrodissection, nonabsorbable suture and the preventive measures to avoid ligating the unnecessary subcutaneous tissues, and between the rate of knot reaction and adoption of assisted forceps, hydrodissection, and the preventive measures. SLPEC was a well-developed procedure for repair of pediatric inguinal hernia/hydrocele. Adoption of assisted forceps, hydrodissection, nonabsorbable suture, and the preventive measures to avoid

  12. Comparison of surgical effect and postoperative patient experience between laparoendoscopic single-site and conventional laparoscopic varicocelectomy: a systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Zheng Zhang

    2017-01-01

    Full Text Available The present meta-analysis was conducted to compare the clinical effect and patient experience of laparoendoscopic single-site varicocelectomy (LESSV and conventional laparoscopic varicocelectomy. The candidate studies were included after literature search of database Cochrane Library, PubMed, EMBASE, and MEDLINE. Related information on essential data and outcome measures was extracted from the eligible studies by two independent authors, and a meta-analysis was conducted using STATA 12.0 software. Subgroup analyses were conducted by study design (RCT and non-RCT. The odds ratio (OR or standardized mean difference (SMD and their 95% confidence intervals (95% CIs were used to estimate the outcome measures. Seven articles were included in our meta-analysis. The results indicated that patient who had undergone LESSV had a shorter duration of back to work (overall: SMD = −1.454, 95% CI: −2.502-−0.405, P = 0.007; non-RCT: SMD = −2.906, 95% CI: −3.796-−2.017, P = 0.000; and RCT: SMD = −0.841, 95% CI: −1.393-−0.289, P = 0.003 and less pain experience at 3 h or 6 h (SMD = −0.447, 95% CI: −0.754-−0.139, P = 0.004, day 1 (SMD = −0.477, 95% CI: −0.905-−0.05, P = 0.029, and day 2 (SMD = −0.612, 95% CI: −1.099-−0.125, P = 0.014 postoperatively based on RCT studies. However, the meta-analyses based on operation time, clinical effect (improvement of semen quality and scrotal pain relief, and complications (hydrocele and recurrence yielded nonsignificant results. In conclusion, LESSV had a rapid recovery and less pain experience over conventional laparoscopic varicocelectomy. However, there was no statistically significant difference between the two varicocelectomy techniques in terms of the clinical effect and the incidence of hydrocele and varicocele recurrence. More high-quality studies are warranted for a comprehensive conclusion.

  13. Catalysis Science Initiative: Catalyst Design by Discovery Informatics

    Energy Technology Data Exchange (ETDEWEB)

    Delgass, William Nicholas [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Abu-Omar, Mahdi [Purdue Univ., West Lafayette, IN (United States) Department of Chemistry; Caruthers, James [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Ribeiro, Fabio [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Thomson, Kendall [Purdue Univ., West Lafayette, IN (United States). Chemical Engineering; Schneider, William [Univ. of Notre Dame, IN (United States)

    2016-07-08

    atoms in the interfacial region. Some of the first theoretical descriptions of this important chemistry and potential new source of control of catalyst properties are be in preparation for submission. On the homogeneous catalysis side, we have used single site olefin polymerization as the testbed. This system is important because changes in a single ligand bonded to the catalytically active metal site can alter the rates of individual steps in the polymerization sequence and thereby change the properties of the resulting polymer, potentially improving its value in a hundred million pound per year industry. We have made a major advance in understanding such systems by developing a population balance kinetic model that allows us to predict the molecular weight distribution (MWD) of the product. That, in turn, allows use of MWD data to fit kinetic parameters. By combining monomer loss data, MWD, measurement of the number of working active sites, and polymer end group analysis, we have a rich data set that is highly discriminating of kinetic mechanism. Thus, we have a robust tool for producing high quality, detailed kinetic parameters, which we have used to refine mechanisms presented in the literature and discover relationships between steric and electronic properties of group IV catalysts and individual rate constants in a number of systems. Our recent work on six-coordinate Zr, Ti, and Hf amine bis(phenolate) systems, we have shown that: • The sterics (bulkiness) of the ligands specifically affect the chain termination reaction • The electron density on the metal controls misinsertion (flipped orientation) of the olefin into the growing polymer • Steric effects related to the size of the ortho ligand on the catalyst have been shown to strongly affect its the degree of dormancy, i.e. tendency to stop reacting • Changes in the size of the amine pendent group on the catalyst can have such a strong effect on chain termination as to change the catalyst from one that

  14. Nanostructured catalysts for organic transformations.

    Science.gov (United States)

    Chng, Leng Leng; Erathodiyil, Nandanan; Ying, Jackie Y

    2013-08-20

    The development of green, sustainable and economical chemical processes is one of the major challenges in chemistry. Besides the traditional need for efficient and selective catalytic reactions that will transform raw materials into valuable chemicals, pharmaceuticals and fuels, green chemistry also strives for waste reduction, atomic efficiency and high rates of catalyst recovery. Nanostructured materials are attractive candidates as heterogeneous catalysts for various organic transformations, especially because they meet the goals of green chemistry. Researchers have made significant advances in the synthesis of well-defined nanostructured materials in recent years. Among these are novel approaches that have permitted the rational design and synthesis of highly active and selective nanostructured catalysts by controlling the structure and composition of the active nanoparticles (NPs) and by manipulating the interaction between the catalytically active NP species and their support. The ease of isolation and separation of the heterogeneous catalysts from the desired organic product and the recovery and reuse of these NPs further enhance their attractiveness as green and sustainable catalysts. This Account reviews recent advances in the use of nanostructured materials for catalytic organic transformations. We present a broad overview of nanostructured catalysts used in different types of organic transformations including chemoselective oxidations and reductions, asymmetric hydrogenations, coupling reactions, C-H activations, oxidative aminations, domino and tandem reactions, and more. We focus on recent research efforts towards the development of the following nanostructured materials: (i) nanostructured catalysts with controlled morphologies, (ii) magnetic nanocomposites, (iii) semiconductor-metal nanocomposites, and (iv) hybrid nanostructured catalysts. Selected examples showcase principles of nanoparticle design such as the enhancement of reactivity, selectivity

  15. Capability-based computer systems

    CERN Document Server

    Levy, Henry M

    2014-01-01

    Capability-Based Computer Systems focuses on computer programs and their capabilities. The text first elaborates capability- and object-based system concepts, including capability-based systems, object-based approach, and summary. The book then describes early descriptor architectures and explains the Burroughs B5000, Rice University Computer, and Basic Language Machine. The text also focuses on early capability architectures. Dennis and Van Horn's Supervisor; CAL-TSS System; MIT PDP-1 Timesharing System; and Chicago Magic Number Machine are discussed. The book then describes Plessey System 25

  16. Industrial recovery capability. Final report

    International Nuclear Information System (INIS)

    Gregg, D.W.

    1984-12-01

    This report provides an evaluation of the vulnerability - to a nuclear strike, terrorist attack, or natural disaster - of our national capacity to produce chlorine, beryllium, and a particular specialty alumina catalyst required for the production of sulfur. All of these industries are of critical importance to the United States economy. Other industries that were examined and found not to be particularly vulnerable are medicinal drugs and silicon wafers for electronics. Thus, only the three more vulnerable industries are addressed in this report

  17. Additive Manufacturing of Catalyst Substrates for Steam-Methane Reforming

    Science.gov (United States)

    Kramer, Michelle; McKelvie, Millie; Watson, Matthew

    2018-01-01

    Steam-methane reforming is a highly endothermic reaction, which is carried out at temperatures up to 1100 °C and pressures up to 3000 kPa, typically with a Ni-based catalyst distributed over a substrate of discrete alumina pellets or beads. Standard pellet geometries (spheres, hollow cylinders) limit the degree of mass transfer between gaseous reactants and catalyst. Further, heat is supplied to the exterior of the reactor wall, and heat transfer is limited due to the nature of point contacts between the reactor wall and the substrate pellets. This limits the degree to which the process can be intensified, as well as limiting the diameter of the reactor wall. Additive manufacturing now gives us the capability to design structures with tailored heat and mass transfer properties, not only within the packed bed of the reactor, but also at the interface between the reactor wall and the packed bed. In this work, the use of additive manufacturing to produce monolithic-structured catalyst substrate models, made from acrylonitrile-butadiene-styrene, with enhanced conductive heat transfer is described. By integrating the reactor wall into the catalyst substrate structure, the effective thermal conductivity increased by 34% from 0.122 to 0.164 W/(m K).

  18. Single-Site VO x Moieties Generated on Silica by Surface Organometallic Chemistry: A Way To Enhance the Catalytic Activity in the Oxidative Dehydrogenation of Propane

    KAUST Repository

    Barman, Samir

    2016-07-26

    We report here an accurate surface organometallic chemistry (SOMC) approach to propane oxidative dehydrogenation (ODH) using a μ2-oxo-bridged, bimetallic [V2O4(acac)2] (1) (acac = acetylacetonate anion) complex as a precursor. The identity and the nuclearity of the product of grafting and of the subsequent oxidative treatment have been systematically studied by means of FT-IR, Raman, solid-state (SS) NMR, UV-vis DRS, EPR and EXAFS spectroscopies. We show that the grafting of 1 on the silica surface under a rigorous SOMC protocol and the subsequent oxidative thermal treatment lead exclusively to well-defined and isolated monovanadate species. The resulting material has been tested for the oxidative dehydrogenation of propane in a moderate temperature range (400-525 °C) and compared with that of silica-supported vanadium catalysts prepared by the standard impregnation technique. The experimental results show that the catalytic activity in propane ODH is strongly upgraded by the degree of isolation of the VOx species that can be achieved by employing the SOMC protocol. © 2016 American Chemical Society.

  19. Sulfur poisoning and regeneration of the Ag/γ-Al2O3 catalyst for H2-assisted SCR of NOx by ammonia

    DEFF Research Database (Denmark)

    Doronkin, Dmitry E.; Khan, Tuhin Suvra; Bligaard, Thomas

    2012-01-01

    Sulfur poisoning and regeneration mechanisms for a 2% Ag/γ-Al2O3 catalyst for the H2-assisted selective catalytic reduction of NOx by NH3 are investigated. The catalyst has medium sulfur tolerance at low temperatures, however a good capability of regeneration at 670°C under lean conditions when H2...

  20. 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

  1. Business models and dynamic capabilities

    OpenAIRE

    Teece, DJ

    2017-01-01

    © 2017 The Author. Business models, dynamic capabilities, and strategy are interdependent. The strength of a firm's dynamic capabilities help shape its proficiency at business model design. Through its effect on organization design, a business model influences the firm's dynamic capabilities and places bounds on the feasibility of particular strategies. While these relationships are understood at a theoretical level, there is a need for future empirical work to flesh out the details. In parti...

  2. Santander and its Dynamic Capabilities

    OpenAIRE

    Cooper, Elizabeth

    2010-01-01

    The purpose of this assignment was to examine the growth of Spanish bank Santander from the strategic perspective of dynamic capabilities. By analysing the content of annual reports, as well as contemporary media accounts and individual interviews with employees, the core competencies and capabilities of the bank have been identified. From this, it has been possible to assess whether such capabilities can be considered as dynamic. This case study has found that there is a very close correlati...

  3. Production of biofuels from synthesis gas using microbial catalysts.

    Science.gov (United States)

    Tirado-Acevedo, Oscar; Chinn, Mari S; Grunden, Amy M

    2010-01-01

    World energy consumption is expected to increase 44% in the next 20 years. Today, the main sources of energy are oil, coal, and natural gas, all fossil fuels. These fuels are unsustainable and contribute to environmental pollution. Biofuels are a promising source of sustainable energy. Feedstocks for biofuels used today such as grain starch are expensive and compete with food markets. Lignocellulosic biomass is abundant and readily available from a variety of sources, for example, energy crops and agricultural/industrial waste. Conversion of these materials to biofuels by microorganisms through direct hydrolysis and fermentation can be challenging. Alternatively, biomass can be converted to synthesis gas through gasification and transformed to fuels using chemical catalysts. Chemical conversion of synthesis gas components can be expensive and highly susceptible to catalyst poisoning, limiting biofuel yields. However, there are microorganisms that can convert the CO, H(2), and CO(2) in synthesis gas to fuels such as ethanol, butanol, and hydrogen. Biomass gasification-biosynthesis processing systems have shown promise as some companies have already been exploiting capable organisms for commercial purposes. The discovery of novel organisms capable of higher product yield, as well as metabolic engineering of existing microbial catalysts, makes this technology a viable option for reducing our dependency on fossil fuels. Copyright 2010 Elsevier Inc. All rights reserved.

  4. Transforming organizational capabilities in strategizing

    DEFF Research Database (Denmark)

    Jørgensen, Claus; Friis, Ole Uhrskov; Koch, Christian

    2014-01-01

    -term evolvements within the companies. We develop our framework of understanding organizational capabilities drawing on dynamic capability, relational capability and strategy as practice concepts, appreciating the performative aspects of developing new routines. Our two cases are taken from one author’s Ph...... reallocated over time thereby creating a growing need for new capabilities and transformed knowledge handling routines. IT emerged into an important resource to support more complex routines of product development as well as specific management and HRM processes assisting the transformation...

  5. Developing Collaborative Product Development Capabilities

    DEFF Research Database (Denmark)

    Mahnke, Volker; Tran, Yen

    2012-01-01

    Collaborative product development capabilities support a company’s product innovation activities. In the context of the fast fashion sector, this paper examines the development of the product development capabilities (PDC) that align product development capabilities in a dual innovation context......, one, slow paced, where the firm is well established and the other, fast paced, which represents a new competitive arena in which the company competes. To understand the process associated with collaborative capability development, we studied three Scandinavian fashion companies pursuing ‘dual...

  6. 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.

  7. Nanocomposite catalyst with palladium nanoparticles encapsulated in a polymeric acid: A model for tandem environmental catalysis

    KAUST Repository

    Isimjan, Tayirjan T.

    2013-04-01

    The synthesis and characterization of a novel hybrid nanocomposite catalyst comprised of palladium nanoparticles embedded in polystyrene sulfonic acid (PSSH) and supported on metal oxides is reported. The catalysts are intended for application in green catalysis, and they are shown to be effective in the hydrolysisreduction sequence of tandem catalytic reactions required for conversion of 2-phenyl-1,3-dioxolane to toluene or of phenol to cyclohexane. The two distinct components in the catalyst, Pd nanoparticles and acidic PSSH, are capable of catalyzing sequential reactions in one pot under mild conditions. This work has demonstrated a powerful approach toward designing highperformance, multifunctional, scalable, and environmentally friendly nanostructured tandem catalysts. © 2013 American Chemical Society.

  8. Use of lanthanide catalysts in air electrodes

    International Nuclear Information System (INIS)

    Souza Parente, L.T. de

    1982-01-01

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

  9. 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.

  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. Paraffin Alkylation Using Zeolite Catalysts in a slurry reactor: Chemical Engineering Principles to Extend Catalyst Lifetime

    NARCIS (Netherlands)

    Jong, K.P. de; Mesters, C.M.A.M.; Peferoen, D.G.R.; Brugge, P.T.M. van; Groot, C. de

    1996-01-01

    The alkylation of isobutane with 2-butene is carried out using a zeolitic catalyst in a well stirred slurry reactor. Whereas application of fixed bed technology using a solid acid alkylation catalyst has in the led to catalysts lifetimes in the range of minutes, in this work we report catalyst

  12. 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

  13. Rhenium Nanochemistry for Catalyst Preparation

    Directory of Open Access Journals (Sweden)

    Vadim G. Kessler

    2012-08-01

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

  14. Hydrothermal performance of catalyst supports

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Jeffrey W.; Marshall, Christopher L.; Libera, Joseph A.; Dumesic, James A.; Pagan-Torres, Yomaira J.

    2018-04-10

    A high surface area catalyst with a mesoporous support structure and a thin conformal coating over the surface of the support structure. The high surface area catalyst support is adapted for carrying out a reaction in a reaction environment where the thin conformal coating protects the support structure within the reaction environment. In various embodiments, the support structure is a mesoporous silica catalytic support and the thin conformal coating comprises a layer of metal oxide resistant to the reaction environment which may be a hydrothermal environment.

  15. Parametric effects and optimization on synthesis of iron (II) doped carbonaceous catalyst for the production of biodiesel

    International Nuclear Information System (INIS)

    Dhawane, Sumit H.; Kumar, Tarkeshwar; Halder, Gopinath

    2016-01-01

    Highlights: • Iron (II) was doped on activated carbon surface. • L9 orthogonal array was used for experimental design using Taguchi approach. • Parametric effects of catalyst synthesis on biodiesel yield were studied. • Agitation speed was emerged as most influential parameter. • Cost analysis of catalyst shows it is cost effective and eco-friendly. - Abstract: Synthesis of efficient and low cost heterogeneous catalyst for transesterification of triglycerides into esters is the need of the hour. The present study elaborates an indigenous development of ferromagnetic iron (II) doped carbonaceous catalyst (Fe/C) for the production of biodiesel from rubber seed oil. The parametric effects on the synthesis of Fe/C catalyst were studied to identify the most significant parameters affecting the biodiesel yield using Taguchi method. The doping process was optimised for maximum biodiesel yield considering four parameters viz. Impregnation time, temperature, catalyst content and agitation speed. The prepared catalyst was characterized using scanning electron microscopy (SEM), X-ray energy dispersive analysis (EDX), X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and Fourier transform infrared spectrometer (FT-IR). The contribution factor revealed that agitation speed is the most influential parameter affecting the biodiesel yield followed by catalyst content, impregnation time and temperature. The maximum biodiesel yield observed in optimum condition of impregnation time 15 h, impregnation temperature 40 °C, catalyst content 5 wt% and agitation speed 500 rpm was 96.31%. The cost analysis of catalyst synthesis was done and found to be fairly economical. The reusability of the catalyst was tested to check the decay in catalytic activity at the optimised condition and found to decrease in activity by 0.8–1.2% after three cycles. Thus, the experimental results and characterization study confirm that indigenously developed carbonaceous catalyst from waste

  16. Stereospecific olefin polymerization with chiral metallocene catalysts

    OpenAIRE

    Brintzinger, Hans-Herbert; Fischer, David; Mülhaupt, Rolf; Rieger, Bernhard; Waymouth, Robert M.

    1995-01-01

    Current studies on novel, metallocenebased catalysts for the polymerization of α-olefins have far-reaching implications for the development of new materials as well as for the understanding of basic reaction mechanisms responsible for the growth of a polymer chain at a catalyst center and the control of its stereoregularity. In contrast to heterogeneous Ziegler–Natta catalysts, polymerization by a homogeneous, metallocene-based catalyst occurs principally at a single type of metal center with...

  17. Rare behaviour of a catalyst pellet catalyst dynamics

    NARCIS (Netherlands)

    Westerterp, K.R.; Loonen, R.A.; Martens, A.

    1986-01-01

    Temperature overshoots and undershoots were found for a Pd on alumina catalyst pellet in its course towards a new steady state after a change in concentration of one of the reactants ethylene or hydrogen. When cooling the pellet, after heat-up by reaction, with pure hydrogen a sudden temperature

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

    Science.gov (United States)

    Gangwal, Santosh; Jothimurugesan, Kandaswamy

    1999-01-01

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

  19. Technological Dynamics and Social Capability

    DEFF Research Database (Denmark)

    Fagerberg, Jan; Feldman, Maryann; Srholec, Martin

    2014-01-01

    for the sample as a whole between 1998 and 2008. The results indicate that social capabilities, such as well-developed public knowledge infrastructure, an egalitarian distribution of income, a participatory democracy and prevalence of public safety condition the growth of technological capabilities. Possible...... effects of other factors, such as agglomeration, urbanization, industrial specialization, migration and knowledge spillovers are also considered....

  20. A Rapid Global Effects Capability

    Science.gov (United States)

    2016-06-01

    Effects Capability within allied countries such as Great Britain and Australia. Other sites recommended for basing included the Ascension Islands in...commercial sectors.23 Figure 2 – Artist depictions of Rapid Global Effects Capability platforms.24 Booster Space Truck...Orbiter) Cargo Bay Booster Space Truck (Orbiter) Cargo Bay Major Gabe S. Arrington 26-1740 10 Figure 3 – Artist depiction of

  1. A business analytics capability framework

    Directory of Open Access Journals (Sweden)

    Ranko Cosic

    2015-09-01

    Full Text Available Business analytics (BA capabilities can potentially provide value and lead to better organisational performance. This paper develops a holistic, theoretically-grounded and practically relevant business analytics capability framework (BACF that specifies, defines and ranks the capabilities that constitute an organisational BA initiative. The BACF was developed in two phases. First, an a priori conceptual framework was developed based on the Resource-Based View theory of the firm and a thematic content analysis of the BA literature. Second, the conceptual framework was further developed and refined using a three round Delphi study involving 16 BA experts. Changes from the Delphi study resulted in a refined and confirmed framework including detailed capability definitions, together with a ranking of the capabilities based on importance. The BACF will help academic researchers and industry practitioners to better understand the capabilities that constitute an organisational BA initiative and their relative importance. In future work, the capabilities in the BACF will be operationalised to measure their as-is status, thus enabling organisations to identify key areas of strength and weakness and prioritise future capability improvement efforts.

  2. Structure of silica-supported catalysts

    International Nuclear Information System (INIS)

    Gladden, L.F.; Vignaux, M.; Griffiths, R.W.; Jackson, S.D.; Jones, J.R.; Sharratt, A.P.; Robertson, F.J.; Webb, G.

    1992-01-01

    Neutron diffraction and SANS studies of silica supported metal catalysts have indicated that more active metal:silica catalysts are produced when the silica support has a relatively high content of three-membered rings in its network structure. SANS studies also suggest that the more active catalysts possess a bimodal metal particle size distribution. (orig.)

  3. 40 CFR 721.9665 - Organotin catalysts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Organotin catalysts. 721.9665 Section... Substances § 721.9665 Organotin catalysts. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substances identified generically as organotin catalysts (PMNs P-93-853, P-93...

  4. Catalysts and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Slowing, Igor Ivan; Kandel, Kapil

    2017-02-14

    The present invention provides a catalyst including a mesoporous silica nanoparticle and a catalytic material comprising iron. In various embodiments, the present invention provides methods of using and making the catalyst. In some examples, the catalyst can be used to hydrotreat fatty acids or to selectively remove fatty acids from feedstocks.

  5. 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...

  6. 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....

  7. Low platinum catalyst and method of preparation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Di-Jia; Chong, Lina

    2017-11-21

    A low platinum catalyst and method for making same. The catalyst comprises platinum-transition metal bimetallic alloy microcrystallites over a transition metal-nitrogen-carbon composite. A method of making a catalyst comprises preparation of transition metal organic frameworks, infusion of platinum, thermal treatment, and reduction to form the microcrystallites and composite.

  8. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  9. Organometallic model complexes elucidate the active gallium species in alkane dehydrogenation catalysts based on ligand effects in Ga K-edge XANES

    Energy Technology Data Exchange (ETDEWEB)

    Getsoian, Andrew “Bean”; Das, Ujjal; Camacho-Bunquin, Jeffrey; Zhang, Guanghui; Gallagher, James R.; Hu, Bo; Cheah, Singfoong; Schaidle, Joshua A.; Ruddy, Daniel A.; Hensley, Jesse E.; Krause, Theodore R.; Curtiss, Larry A.; Miller, Jeffrey T.; Hock, Adam S.

    2016-01-01

    Gallium-modified zeolites are known catalysts for the dehydrogenation of alkanes, reactivity that finds industrial application in the aromatization of light alkanes by Ga-ZSM5. While the role of gallium cations in alkane activation is well known, the oxidation state and coordination environment of gallium under reaction conditions has been the subject of debate. Edge shifts in Ga K-edge XANES spectra acquired under reaction conditions have long been interpreted as evidence for reduction of Ga(III) to Ga(I). However, a change in oxidation state is not the only factor that can give rise to a change in the XANES spectrum. In order to better understand the XANES spectra of working catalysts, we have synthesized a series of molecular model compounds and grafted surface organometallic Ga species and compared their XANES spectra to those of gallium-based catalysts acquired under reducing conditions. We demonstrate that changes in the identity and number of gallium nearest neighbors can give rise to changes in XANES spectra similar to those attributed in literature to changes in oxidation state. Specifically, spectral features previously attributed to Ga(I) may be equally well interpreted as evidence for low-coordinate Ga(III) alkyl or hydride species. These findings apply both to gallium-impregnated zeolite catalysts and to silica-supported single site gallium catalysts, the latter of which is found to be active and selective for dehydrogenation of propane and hydrogenation of propylene.

  10. Transitioning Rationally Designed Catalytic Materials to Real 'Working' Catalysts Produced at Commercial Scale: Nanoparticle Materials

    Energy Technology Data Exchange (ETDEWEB)

    Schaidle, Joshua A.; Habas, Susan E.; Baddour, Frederick G.; Farberow, Carrie A.; Ruddy, Daniel A.; Hensley, Jesse E.; Brutchey, Richard L.; Malmstadt, Noah; Robota, Heinz

    2017-02-01

    Catalyst design, from idea to commercialization, requires multi-disciplinary scientific and engineering research and development over 10-20 year time periods. Historically, the identification of new or improved catalyst materials has largely been an empirical trial-and-error process. However, advances in computational capabilities (new tools and increased processing power) coupled with new synthetic techniques have started to yield rationally-designed catalysts with controlled nano-structures and tailored properties. This technological advancement represents an opportunity to accelerate the catalyst development timeline and to deliver new materials that outperform existing industrial catalysts or enable new applications, once a number of unique challenges associated with the scale-up of nano-structured materials are overcome.

  11. Alternative deNO{sub x} catalysts and technologies

    Energy Technology Data Exchange (ETDEWEB)

    Due-Hansen, J.

    2010-06-15

    Two approaches are undertaken in the present work to reduce the emission of NO{sub x}: by means of catalytic removal, and by NO absorption in ionic liquids. The commercial catalyst used for the selective catalytic reduction (SCR) of nitrogen oxides exhibits high activity and selectivity towards N{sub 2}. However, the vanadia-titania-based catalyst used is very sensitive to deactivation by alkali-species (primarily potassium), which are typically present in high amounts in the flue gas when biomass is combusted. By co-firing with large amounts of CO{sub 2}-neutral straw or wood (to meet stringent CO{sub 2} emission legislation), the lifetime of the traditional SCR catalyst is thus significantly reduced due to the presence of deactivating species originating from the fuel. To develop a catalyst less susceptible to the poisons present in the flue gas, a number of catalysts have been synthesized and tested in the present work, all based on commercially available supports. A highly acidic support consisting of sulfated zirconia was chosen based on preliminary studies. A number of different active species distributed on the support were investigated, such as iron, copper and vanadium oxides. However, based on the catalysts performance in the SCR reaction and their resistances towards potassium, the most promising candidate of the formulations studied was the vanadia-loaded catalyst, i.e. V{sub 2}O{sub 5}-SO{sub 4}2-ZrO{sub 2}. This work, together with an introduction to the catalytic removal of NO{sub x}, are described in chapter 3. The remainder of the first part is concerned with the catalytic NO{sub x} removal (chapter 4) and it addresses the upscaling of the best catalyst candidate. The catalyst was mixed with the natural binding clay (sepiolite) to upscale the selected catalyst to the monolithic level, suitable for installation in gas stream with high flows, e.g. a flue gas duct of a power plant. A series of catalyst pellets with increasing levels of sepiolite were

  12. Capabilities and Incapabilities of the Capabilities Approach to Health Justice.

    Science.gov (United States)

    Selgelid, Michael J

    2016-01-01

    This first part of this article critiques Sridhar Venkatapuram's conception of health as a capability. It argues that Venkatapuram relies on the problematic concept of dignity, implies that those who are unhealthy lack lives worthy of dignity (which seems politically incorrect), sets a low bar for health, appeals to metaphysically problematic thresholds, fails to draw clear connections between appealed-to capabilities and health, and downplays the importance/relevance of health functioning. It concludes by questioning whether justice entitlements should pertain to the capability for health versus health achievements, challenging Venkatapuram's claims about the strength of health entitlements, and demonstrating that the capabilities approach is unnecessary to address social determinants of health. © 2016 John Wiley & Sons Ltd.

  13. Perovskite catalysts for oxidative coupling

    Science.gov (United States)

    Campbell, Kenneth D.

    1991-01-01

    Perovskites of the structure A.sub.2 B.sub.2 C.sub.3 O.sub.10 are useful as catalysts for the oxidative coupling of lower alkane to heavier hydrocarbons. A is alkali metal; B is lanthanide or lanthanum, cerium, neodymium, samarium, praseodymium, gadolinium or dysprosium; and C is titanium.

  14. Organic Synthesis using Clay Catalysts

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 1. Organic Synthesis using Clay Catalysts - Clays for 'Green Chemistry'. Gopalpur Nagendrappa. General Article Volume 7 Issue 1 January 2002 pp 64-77. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. The Bosch Process-Performance of a Developmental Reactor and Experimental Evaluation of Alternative Catalysts

    Science.gov (United States)

    Abney, Morgan B.; Mansell, J. Matthew

    2010-01-01

    Bosch-based reactors have been in development at NASA since the 1960's. Traditional operation involves the reduction of carbon dioxide with hydrogen over a steel wool catalyst to produce water and solid carbon. While the system is capable of completely closing the loop on oxygen and hydrogen for Atmosphere Revitalization, steel wool requires a reaction temperature of 650C or higher for optimum performance. The single pass efficiency of the reaction over steel wool has been shown to be less than 10% resulting in a high recycle stream. Finally, the formation of solid carbon on steel wool ultimately fouls the catalyst necessitating catalyst resupply. These factors result in high mass, volume and power demands for a Bosch system. Interplanetary transportation and surface exploration missions of the moon, Mars, and near-earth objects will require higher levels of loop closure than current technology cannot provide. A Bosch system can provide the level of loop closure necessary for these long-term missions if mass, volume, and power can be kept low. The keys to improving the Bosch system lie in reactor and catalyst development. In 2009, the National Aeronautics and Space Administration refurbished a circa 1980's developmental Bosch reactor and built a sub-scale Bosch Catalyst Test Stand for the purpose of reactor and catalyst development. This paper describes the baseline performance of two commercially available steel wool catalysts as compared to performance reported in the 1960's and 80's. Additionally, the results of sub-scale testing of alternative Bosch catalysts, including nickel- and cobalt-based catalysts, are discussed.

  16. Marketing Capability in Strategy Research

    DEFF Research Database (Denmark)

    Ritter, Thomas; Distel, Andreas Philipp

    Following the call for a demand-side perspective of strategic management (e.g., Priem et al., 2012), a firm’s marketing capability, i.e. its ability to interact with down-stream stakeholders, becomes a pivotal element in explaining a firm’s competitiveness. While marketing capability is recognize...... ground for advancing marketing capability research and thus supporting the demand-side perspective in strategic management, we develop an integrative framework to explain the differences and propose a research agenda for developing the field.......Following the call for a demand-side perspective of strategic management (e.g., Priem et al., 2012), a firm’s marketing capability, i.e. its ability to interact with down-stream stakeholders, becomes a pivotal element in explaining a firm’s competitiveness. While marketing capability is recognized...... in the strategic management literature as an important driver of firm performance, our review of 86 articles reveals a lack of a generally accepted definition of marketing capability, a lack of a common conceptualization as well as differences in the measurement of marketing capability. In order to build a common...

  17. Cellulose Depolymerization over Heterogeneous Catalysts.

    Science.gov (United States)

    Shrotri, Abhijit; Kobayashi, Hirokazu; Fukuoka, Atsushi

    2018-02-14

    Cellulosic biomass is the largest source of renewable organic carbon on our planet. Cellulose accounts for 40-50 wt % of this lignocellulose, and it is a feedstock for industrially important chemicals and fuels. The first step in cellulose conversion involves its depolymerization to glucose or to its hydrogenated product sorbitol. The hydrolysis of cellulose to glucose by homogeneous mineral acids was the subject of research for almost a century. However, homogeneous acids have significant drawbacks and are neither economical nor environmentally friendly. In 2006, our group reported for the first time the ability of heterogeneous catalysts to depolymerize cellulose through hydrolytic hydrogenation to produce sorbitol. Later, we reported the hydrolysis of cellulose to glucose using carbon catalyst containing weakly acidic functional groups. Understanding the reaction between cellulose and heterogeneous catalyst is a challenge as the reaction occurs between a solid substrate and a solid catalyst. In this Account, we describe our efforts for the conversion of cellulose to sorbitol and glucose using heterogeneous catalysts. Sorbitol is produced by sequential hydrolysis and hydrogenation of cellulose in one pot. We reported sorbitol synthesis from cellulose in the presence of supported metal catalysts and H 2 gas. The reducing environment of the reaction prevents byproduct formation, and harsh reaction conditions can be used to achieve sorbitol yield of up to 90%. Glucose is produced by acid catalyzed hydrolysis of cellulose, a more challenging reaction owing to the tendency of glucose to rapidly decompose in hot water. Sulfonated carbons were first reported as active catalysts for cellulose hydrolysis, but they were hydrothermally unstable under the reaction conditions. We found that carbon catalysts bearing weakly acidic functional groups such as hydroxyl and carboxylic acids are also active. Weakly acidic functional groups are hydrothermally stable, and a soluble

  18. Industrial production of catalyst 5058

    Energy Technology Data Exchange (ETDEWEB)

    von Fuener, W.

    1943-05-03

    Catalyst 5058 was tungsten sulfide, WS/sub 2/. It was produced from tungstic acid, WO/sub 3/.H/sub 2/O, which was itself produced from concentrated tungsten ores. The formation of tungstic acid from the ore proceeded in two or three cycles of dissolving the substance in a base (sodium hydroxide, ammonia, lime), decomposing the result with acid, and the filtering, washing, and drying the resulting impure tungstic acid. The final tungstic acid had only about 0.2% impurities. The formation of tungsten sulfide from the tungstic acid proceeded in several steps. First, the tungstic acid was reacted with ammonium hydroxide to give ammonium tungstate, (NH/sub 4/)/sub 2/WO/sub 4/, which was then saturated with hydrogen sulfide to give ammonium sulfotungstate, (NH/sub 4/)/sub 2/WS/sub 4/, which precipitated out of solution at reduced temperature as monoclinic crystals in an orange-red powder. The saturation itself had to be done at about 70/sup 0/C to prevent formation (and later coprecipitation) of an interfering oxysulfate compound, (NH/sub 4/)/sub 2/WO/sub 2/S/sub 2/. The ammonium sulfotungstate precipitate was filtered out under suction and dried in hydrogen in a steam-heated vessel. The ammonium sulfotungstate was then decomposed in a stream of hydrogen in a furnace, at high temperature, to give tungsten sulfide in a monoclinic crystalline structure, which was different from the usual hexagonal crystal structure of tungsten sulfide. The resulting porous structure of the crystal lattice contributed to the activity of the catalyst. Finally, the catalyst was powdered into a fine powder and then compressed into cylindrical tablets as the form in which the catalyst was introduced into the hydrogenation ovens for use. Regeneration of the catalyst was necessary after 1 or 2 years of use.

  19. 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.

  20. Operando chemistry of catalyst surfaces during catalysis.

    Science.gov (United States)

    Dou, Jian; Sun, Zaicheng; Opalade, Adedamola A; Wang, Nan; Fu, Wensheng; Tao, Franklin Feng

    2017-04-03

    Chemistry of a catalyst surface during catalysis is crucial for a fundamental understanding of mechanism of a catalytic reaction performed on the catalyst in the gas or liquid phase. Due to the pressure- or molecular density-dependent entropy contribution of gas or liquid phase of the reactants and the potential formation of a catalyst surface during catalysis different from that observed in an ex situ condition, the characterization of the surface of a catalyst under reaction conditions and during catalysis can be significant and even necessary for understanding the catalytic mechanism at a molecular level. Electron-based analytical techniques are challenging for studying catalyst nanoparticles in the gas or liquid phase although they are necessary techniques to employ. Instrumentation and further development of these electron-based techniques have now made in situ/operando studies of catalysts possible. New insights into the chemistry and structure of catalyst nanoparticles have been uncovered over the last decades. Herein, the origin of the differences between ex situ and in situ/operando studies of catalysts, and the technical challenges faced as well as the corresponding instrumentation and innovations utilized for characterizing catalysts under reaction conditions and during catalysis, are discussed. The restructuring of catalyst surfaces driven by the pressure of reactant(s) around a catalyst, restructuring in reactant(s) driven by reaction temperature and restructuring during catalysis are also reviewed herein. The remaining challenges and possible solutions are briefly discussed.

  1. Advanced Capabilities for Combat Medics

    National Research Council Canada - National Science Library

    Convertino, Victor A; Cooke, William H; Salinas, Jose; Holcomb, John B

    2004-01-01

    The US Army Institute of Surgical Research (USAISR) has the lead for directing the Research Program Area for Advanced Triage Capabilities for Combat Medics in the Medical Research and Materiel Command (MRMC...

  2. Autothermal reforming catalyst having perovskite structure

    Science.gov (United States)

    Krumpel, Michael [Naperville, IL; Liu, Di-Jia [Naperville, IL

    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.

  3. Automated synthesis of a 96 product-sized library of triazole derivatives using a solid phase supported copper catalyst.

    Science.gov (United States)

    Jlalia, Ibtissem; Beauvineau, Claire; Beauvière, Sophie; Onen, Esra; Aufort, Marie; Beauvineau, Aymeric; Khaba, Eihab; Herscovici, Jean; Meganem, Faouzi; Girard, Christian

    2010-04-28

    This article deal with the parallel synthesis of a 96 product-sized library using a polymer-based copper catalyst that we developed which can be easily separated from the products by simple filtration. This gave us the opportunity to use this catalyst in an automated chemical synthesis station (Chemspeed ASW-2000). Studies and results about the preparation of the catalyst, its use in different solvent systems, its recycling capabilities and its scope and limitations in the synthesis of this library will be addressed. The synthesis of the triazole library and the very good results obtained will finally be discussed.

  4. Building server capabilities in China

    DEFF Research Database (Denmark)

    Adeyemi, Oluseyi; Slepniov, Dmitrij; Wæhrens, Brian Vejrum

    2012-01-01

    The purpose of this paper is to further our understanding of multinational companies building server capabilities in China. The paper is based on the cases of two western companies with operations in China. The findings highlight a number of common patterns in the 1) managerial challenges related...... to the development of server capabilities at offshore sites, and 2) means of how these challenges can be handled....

  5. Catalyst for Carbon Monoxide Oxidation

    Science.gov (United States)

    Davis, Patricia; Brown, Kenneth; VanNorman, John; Brown, David; Upchurch, Billy; Schryer, David; Miller, Irvin

    2010-01-01

    In many applications, it is highly desirable to operate a CO2 laser in a sealed condition, for in an open system the laser requires a continuous flow of laser gas to remove the dissociation products that occur in the discharge zone of the laser, in order to maintain a stable power output. This adds to the operating cost of the laser, and in airborne or space applications, it also adds to the weight penalty of the laser. In a sealed CO2 laser, a small amount of CO2 gas is decomposed in the electrical discharge zone into corresponding quantities of CO and O2. As the laser continues to operate, the concentration of CO2 decreases, while the concentrations of CO and O2 correspondingly increase. The increasing concentration of O2 reduces laser power, because O2 scavenges electrons in the electrical discharge, thereby causing arcing in the electric discharge and a loss of the energetic electrons required to boost CO2 molecules to lasing energy levels. As a result, laser power decreases rapidly. The primary object of this invention is to provide a catalyst that, by composition of matter alone, contains chemisorbed water within and upon its structure. Such bound moisture renders the catalyst highly active and very long-lived, such that only a small quantity of it needs to be used with a CO2 laser under ambient operating conditions. This object is achieved by a catalyst that consists essentially of about 1 to 40 percent by weight of one or more platinum group metals (Pt, Pd, Rh, Ir, Ru, Os, Pt being preferred); about 1 to 90 percent by weight of one or more oxides of reducible metals having multiple valence states (such as Sn, Ti, Mn, Cu, and Ce, with SnO2 being preferred); and about 1 to 90 percent by weight of a compound that can bind water to its structure (such as silica gel, calcium chloride, magnesium sulfate, hydrated alumina, and magnesium perchlorate, with silica gel being preferred). Especially beneficial results are obtained when platinum is present in the

  6. Production of phenolic-rich bio-oil from catalytic fast pyrolysis of biomass using magnetic solid base catalyst

    International Nuclear Information System (INIS)

    Zhang, Zhi-bo; Lu, Qiang; Ye, Xiao-ning; Li, Wen-tao; Hu, Bin; Dong, Chang-qing

    2015-01-01

    Highlights: • Phenolic-rich bio-oil was selectively produced from catalytic fast pyrolysis of biomass using magnetic solid base catalyst. • The actual yield of twelve major phenolic compounds reached 43.9 mg/g. • The peak area% of all phenolics reached 68.5% at the catalyst-to-biomass ratio of 7. • The potassium phosphate/ferroferric oxide catalyst possessed promising recycling properties. - Abstract: A magnetic solid base catalyst (potassium phosphate/ferroferric oxide) was prepared and used for catalytic fast pyrolysis of poplar wood to selectively produce phenolic-rich bio-oil. Pyrolysis–gas chromatography/mass spectrometry experiments were conducted to investigate the effects of pyrolysis temperature and catalyst-to-biomass ratio on the product distribution. The actual yields of important pyrolytic products were quantitatively determined by the external standard method. Moreover, recycling experiments were performed to determine the re-utilization abilities of the catalyst. The results showed that the catalyst exhibited promising activity to selectively produce phenolic-rich bio-oil, due to its capability of promoting the decomposition of lignin to generate phenolic compounds and meanwhile inhibiting the devolatilization of holocellulose. The maximal phenolic yield was obtained at the pyrolysis temperature of 400 °C and catalyst-to-biomass ratio of 2. The concentration of the phenolic compounds increased monotonically along with the increasing of the catalyst-to-biomass ratio, with the peak area% value increasing from 28.1% in the non-catalytic process to as high as 68.5% at the catalyst-to-biomass ratio of 7. The maximal total actual yield of twelve quantified major phenolic compounds was 43.9 mg/g, compared with the value of 29.0 mg/g in the non-catalytic process. In addition, the catalyst could be easily recovered and possessed promising recycling properties.

  7. Development of Students Learning Capabilities and Professional Capabilities

    DEFF Research Database (Denmark)

    Ringtved, Ulla Lunde; Wahl, Christian; Belle, Gianna

    This paper describes the work-in-progress on a project that aims to develop a tool that via learning analytic methods enable students to enhance, document and assess the development of their learning capabilities and professional capabilities in consequence of their self-initiated study activities...... as well as self-assessing them. The tool is based on a heutagogical approach to support reflection on learning potential in these activities. This enhances the educational use of students self-initiated learning activities by bringing visibility and evidence to them, and thereby bringing value...... during their bachelor educations. The tool aims at enhancing the development of students’ capabilities to self-initiate, self-regulate and self-assess their study activities. The tool uses the concept of collective intelligence as source for motivation and inspiration in self-initiating study activities...

  8. Accelerator and electrodynamics capability review

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Kevin W [Los Alamos National Laboratory

    2010-01-01

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  9. Rapid catalyst-free hydrazone ligation: protein-pyridoxal phosphoramides.

    Science.gov (United States)

    Wang, Xiaojian; Canary, James W

    2012-12-19

    Pyridoxal-5'-phosphate (PLP) represents an active form of Vitamin B(6) that shows relatively fast imine formation with hydrazines under physiological conditions without the need of a catalyst. A convenient phosphate/amine conjugation protocol was developed to covalently link PLP to proteins, affording proteins capable of hydrazone formation with bioorthogonal hydrazinyl functional groups. Thus, the lectin Concanavalin A (Con A) was labeled with PLP. Pretreatment with fluorescein hydrazide gave dye-labeled Con A that labeled cell surfaces efficiently. Alternatively, pretargeting was achieved by labeling cells with Con A-PLP, then treatment in vitro with Alexa Fluor 488 hydrazide.

  10. Polymerization catalyst, production and use

    International Nuclear Information System (INIS)

    Best, S.A.

    1987-01-01

    A process is described for polymerization of ethylene and alpha-olefins having from 1 to 20 carbon atoms or mixtures of ethylene, alpha-olefins and diolefins. The process comprises polymerizing one or more olefins in the presence of the catalyst system comprising (a) an organoaluminum cocatalyst, and (b) a vanadium containing a catalyst component obtained by treating an inert solid support material in an inert solvent with (i) an organoaluminum compound represented by the formula R/sub m/AIX/sub 3-m/, wherein R represents an alkyl group, cycloalkyl group or aryl group having from 1 to 18 carbon atoms, X represents halogen atoms, and 1≤m≤3, (ii) an acyl halide, and (iii) a vanadium compound. Another process is identified wherein the inert solid support material is an inorganic oxide or mixtures of inorganic oxides. Also a process wherein the inorganic oxide is silica is described

  11. Polymerization catalyst, production and use

    International Nuclear Information System (INIS)

    Best, S.A.

    1987-01-01

    A process is described for the polymerization of ethylene and alpha-olefins having from 1 to 2 carbon atoms of mixtures of ethylene, alpha-olefins or diolefins. The process comprises polymerizing one or more olefins in the presence of the catalyst system comprising (A) an organo aluminum cocatalyst, and (B) a vanadium-containing catalyst component obtained by sequentially treating an inert solid support material in an inert solvent with (i) a dihydrocarbyl magnesium compound, (ii) optionally an oxygen-containing compound which is an alcohol, ketone or aldehyde, (iii) a vanadium compound, and (iv) a Group IIIa metal halide. The process as above is described wherein the inert solid support material is an inorganic oxide or mixtures of inorganic oxides

  12. Biodiesel production using heterogeneous catalysts.

    Science.gov (United States)

    Semwal, Surbhi; Arora, Ajay K; Badoni, Rajendra P; Tuli, Deepak K

    2011-02-01

    The production and use of biodiesel has seen a quantum jump in the recent past due to benefits associated with its ability to mitigate greenhouse gas (GHG). There are large number of commercial plants producing biodiesel by transesterification of vegetable oils and fats based on base catalyzed (caustic) homogeneous transesterification of oils. However, homogeneous process needs steps of glycerol separation, washings, very stringent and extremely low limits of Na, K, glycerides and moisture limits in biodiesel. Heterogeneous catalyzed production of biodiesel has emerged as a preferred route as it is environmentally benign needs no water washing and product separation is much easier. The present report is review of the progress made in development of heterogeneous catalysts suitable for biodiesel production. This review shall help in selection of suitable catalysts and the optimum conditions for biodiesel production. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Catalyst for Expanding Human Spaceflight

    Science.gov (United States)

    Lueders, Kathryn L.

    2014-01-01

    History supplies us with many models of how and how not to commercialize an industry. This presentation draws parallels between industries with government roots, like the railroad, air transport, communications and the internet, and NASAs Commercial Crew Program. In these examples, government served as a catalyst for what became a booming industry. The building block approach the Commercial Crew Program is taking is very simple -- establish a need, laying the groundwork, enabling industry and legal framework.

  14. Conversion of a beta-strand to an alpha-helix induced by a single-site mutation observed in the crystal structure of Fis mutant Pro26Ala.

    OpenAIRE

    Yang, W. Z.; Ko, T. P.; Corselli, L.; Johnson, R. C.; Yuan, H. S.

    1998-01-01

    The conversion from an alpha-helix to a beta-strand has received extensive attention since this structural change may induce many amyloidogenic proteins to self-assemble into fibrils and cause fatal diseases. Here we report the conversion of a peptide segment from a beta-strand to an alpha-helix by a single-site mutation as observed in the crystal structure of Fis mutant Pro26Ala determined at 2.0 A resolution. Pro26 in Fis occurs at the point where a flexible extended beta-hairpin arm leaves...

  15. Aromatization of n-octane over Pd/C catalysts

    KAUST Repository

    Yin, Mengchen

    2013-01-01

    Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400-600 °C), weight hourly space velocity (WHSV) (0.8-∞), and hydrogen to hydrocarbon molar ratio (MR) (0-6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h-1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane. © 2012 Elsevier Ltd. All rights reserved.

  16. Technological Capability and Firm Performance

    Directory of Open Access Journals (Sweden)

    Fernanda Maciel Reichert

    2014-08-01

    Full Text Available This research aims to investigate the relationship between investments in technological capability and economic performance in Brazilian firms. Based on economic development theory and on developed countries history, it is assumed that this relationship is positive. Through key indicators, 133 Brazilian firms have been analyzed. Given the economic circumstances of an emerging economy, which the majority of businesses are primarily based on low and medium-low-technology industries, it is not possible to affirm the existence of a positive relation between technological capability and firm performance. There are other elements that allow firms to achieve such results. Firms of lower technological intensity industries performed above average in the economic performance indicators, adversely, they invested below average in technological capability. These findings do not diminish the merit of firms’ and country’s success. They in fact confirm a historical tradition of a country that concentrates its efforts on basic industries.

  17. NWCF maintenance features and capabilities

    International Nuclear Information System (INIS)

    Smith, R.R.; Bingham, G.E.

    A New Waste Calcining Facility is being built at the Idaho Chemical Processing Plant to replace the existing Waste Calcining Facility which was built to demonstrate fluidized-bed solidification of highly radioactive liquid wastes. The new facility is being designed to provide a higher waste throughput, more corrosion resistant materials of construction, more effective cleanup of effluent streams, and extensive remote maintenance and equipment replacement capability. The facility will also contain extensive decontamination capability should contact maintenance become necessary. The facility is presently in construction and is scheduled for hot operation in 1980

  18. Nanofabrication principles, capabilities and limits

    CERN Document Server

    Cui, Zheng

    2017-01-01

    This second edition of Nanofabrication is one of the most comprehensive introductions on nanofabrication technologies and processes. A practical guide and reference, this book introduces readers to all of the developed technologies that are capable of making structures below 100nm. The principle of each technology is introduced and illustrated with minimum mathematics involved. Also analyzed are the capabilities of each technology in making sub-100nm structures, and the limits of preventing a technology from going further down the dimensional scale. This book provides readers with a toolkit that will help with any of their nanofabrication challenges.

  19. Developing Acquisition IS Integration Capabilities

    DEFF Research Database (Denmark)

    Wynne, Peter J.

    2016-01-01

    applies trial and error, experimental, and vicarious learning processes, while actively avoiding improvisational learning. The results of the study contribute to the acquisition IS integration literature specifically by exploring it from a new perspective: the learning processes used by novice acquirers......, an acquiring company must leverage two high level capabilities: diagnosis and integration execution. Through a case study, this paper identifies how a novice acquirer develops these capabilities in anticipation of an acquisition by examining its use of learning processes. The study finds the novice acquirer...

  20. Effect of Sn on Isobutane Dehydrogenation Performance of Ni/SiO2Catalyst: Adsorption Modes and Adsorption Energies of Isobutane and Isobutene.

    Science.gov (United States)

    Zhu, Qingqing; Wang, Guowei; Liu, Jianwei; Su, Lushu; Li, Chunyi

    2017-09-13

    The reaction of isobutane over Ni/SiO 2 catalyst changes from hydrogenolysis to dehydrogenation when Sn is introduced. The adsorption modes and energies of isobutane and isobutene over the Ni/SiO 2 catalyst with and without Sn addition were determined by in situ FTIR and a novel transient response adsorption approach. In the absence of Sn, isobutane is adsorbed in a double-site mode with H atoms in two methyl groups of isobutane, facilitating hydrogenolysis of isobutane. After the addition of Sn, a single-site adsorption mode with the H atom in the methylidyne group is speculated instead, which is beneficial to the rupture of the C-H bond rather than the C-C bond. Moreover, the double-site adsorption mode of isobutene with the C═C bond and the H atom in a methyl group is turned into single-site mode with the C═C bond after the introduction of Sn. As for the adsorption energy of isobutene, the introduction of Sn leads to an obvious decrease from 74 to 50 kJ mol -1 and facilitates the prompt desorption of isobutene, resulting in a high selectivity of 81.9 wt %.

  1. Bimetallic platinum group metal-free catalysts for high power generating microbial fuel cells.

    Science.gov (United States)

    Kodali, Mounika; Santoro, Carlo; Herrera, Sergio; Serov, Alexey; Atanassov, Plamen

    2017-10-31

    M1-M2-N-C bimetallic catalysts with M1 as Fe and Co and M2 as Fe, Co, Ni and Mn were synthesized and investigated as cathode catalysts for oxygen reduction reaction (ORR). The catalysts were prepared by Sacrificial Support Method in which silica was the template and aminoantipyrine (AAPyr) was the organic precursor. The electro-catalytic properties of these catalysts were investigated by using rotating ring disk (RRDE) electrode setup in neutral electrolyte. Fe-Mn-AAPyr outperformed Fe-AAPyr that showed higher performances compared to Fe-Co-AAPyr and Fe-Ni-AAPyr in terms of half-wave potential. In parallel, Fe-Co-AAPyr, Co-Mn-AAPyr and Co-Ni-AAPyr outperformed Co-AAPyr. The presence of Co within the catalyst contributed to high peroxide production not desired for efficient ORR. The catalytic capability of the catalysts integrated in air-breathing cathode was also verified. It was found that Co-based catalysts showed an improvement in performance by the addition of second metal compared to simple Co- AAPyr. Fe-based bimetallic materials didn't show improvement compared to Fe-AAPyr with the exception of Fe-Mn-AAPyr catalyst that had the highest performance recorded in this study with maximum power density of 221.8 ± 6.6 μWcm -2 . Activated carbon (AC) was used as control and had the lowest performances in RRDE and achieved only 95.6 ± 5.8 μWcm -2 when tested in MFC.

  2. EFFECTS OF CATALYST MORPHOLOGY ON HYDROTREATING REACTIONS

    Directory of Open Access Journals (Sweden)

    TYE CHING THIAN

    2008-08-01

    Full Text Available 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 catalysts with different morphology were studied. They are crystalline MoS2, exfoliated MoS2 and MoS2 derived from a precursor, molybdenum naphthenate. Exfoliated MoS2 with minimal long range order, with much higher rim edges has shown relative higher hydrogenation activity. Generally, results of MoS2 catalyst activities in hydrogenation, hydrodesulfurization, hydrodenitrogenation and hydrideoxy¬gena¬tion are in agreement with the rim-edge model.

  3. Organic synthesis with olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grubbs, R.H. [California Institute of Technology, Pasadena, CA (United States)

    1995-12-31

    Over the past nine years, early transition metal catalysts for the ring opening metathesis polymerization of cyclic olefins have been developed. These catalysts are simple organometallic complexes containing metal carbon multiple bonds that in most cases polymerize olefins by a living process. These catalysts have been used to prepare a family of near monodispersed and structurally homogeneous polymers. A series of group VII ROMP catalysts that allow a wide range of functionality to be incorporated into the polymer side chains have been prepared. The most important member of this family of complexes are the bisphosphinedihalo-ruthenium carbene complexes. These polymerization catalysts can also be used in the synthesis of fine chemicals by ring closing (RCM) and vinyl coupling reactions. The availability of the group VII catalysts allow metathesis to be carried out on highly functionalized substrates such as polypeptides and in unusual environments such as in aqueous emulsions.

  4. Optimization of catalyst system reaps economic benefits

    International Nuclear Information System (INIS)

    Le Roy, C.F.; Hanshaw, M.J.; Fischer, S.M.; Malik, T.; Kooiman, R.R.

    1991-01-01

    Champlin Refining and Chemicals Inc. is learning to optimize its catalyst systems for hydrotreating Venezuelan gas oils through a program of research, pilot plant testing, and commercial unit operation. The economic results of this project have been evaluated, and the benefits are most evident in improvements in product yields and qualities. The project has involved six commercial test runs, to date (Runs 10-15), with a seventh run planned. A summary of the different types of catalyst systems used in the test runs, and the catalyst philosophy that developed is given. Runs 10 and 11 used standard CoMo and NiMo catalysts for heavy gas oils hydrotreating. These catalysts had small pore sizes and suffered high deactivation rates because of metals contamination. When it was discovered that metals contamination was a problem, catalyst options were reviewed

  5. Alternative deNOx catalysts and technologies

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes

    . The commercial catalyst used for the selective catalytic reduction (SCR) of nitrogen oxides exhibits high activity and selectivity towards N2. However, the vanadia-titania-based catalyst used is very sensitive to deactivation by alkali-species (primarily potassium), which are typically present in high amounts...... a catalyst less susceptible to the poisons present in the flue gas, a number of catalysts have been synthesized and tested in the present work, all based on commercially available supports. A highly acidic support consisting of sulfated zirconia was chosen based on preliminary studies. A number of different...... active species distributed on the support were investigated, such as iron, copper and vanadium oxides. However, based on the catalysts performance in the SCR reaction and their resistances towards potassium, the most promising candidate of the formulations studied was the vanadia-loaded catalyst, i.e. V2...

  6. Toward molecular catalysts by computer.

    Science.gov (United States)

    Raugei, Simone; DuBois, Daniel L; Rousseau, Roger; Chen, Shentan; Ho, Ming-Hsun; Bullock, R Morris; Dupuis, Michel

    2015-02-17

    CONSPECTUS: Rational design of molecular catalysts requires a systematic approach to designing ligands with specific functionality and precisely tailored electronic and steric properties. It then becomes possible to devise computer protocols to design catalysts by computer. In this Account, we first review how thermodynamic properties such as redox potentials (E°), acidity constants (pKa), and hydride donor abilities (ΔGH(-)) form the basis for a framework for the systematic design of molecular catalysts for reactions that are critical for a secure energy future. We illustrate this for hydrogen evolution and oxidation, oxygen reduction, and CO conversion, and we give references to other instances where it has been successfully applied. The framework is amenable to quantum-chemical calculations and conducive to predictions by computer. We review how density functional theory allows the determination and prediction of these thermodynamic properties within an accuracy relevant to experimentalists (∼0.06 eV for redox potentials, ∼1 pKa unit for pKa values, and 1-2 kcal/mol for hydricities). Computation yielded correlations among thermodynamic properties as they reflect the electron population in the d shell of the metal center, thus substantiating empirical correlations used by experimentalists. These correlations point to the key role of redox potentials and other properties (pKa of the parent aminium for the proton-relay-based catalysts designed in our laboratory) that are easily accessible experimentally or computationally in reducing the parameter space for design. These properties suffice to fully determine free energies maps and profiles associated with catalytic cycles, i.e., the relative energies of intermediates. Their prediction puts us in a position to distinguish a priori between desirable and undesirable pathways and mechanisms. Efficient catalysts have flat free energy profiles that avoid high activation barriers due to low- and high

  7. Liquid phase low temperature method for production of methanol from synthesis gas and catalyst formulations therefor

    Science.gov (United States)

    Mahajan, Devinder

    2005-07-26

    The invention provides a homogenous catalyst for the production of methanol from purified synthesis gas at low temperature and low pressure which includes a transition metal capable of forming transition metal complexes with coordinating ligands and an alkoxide, the catalyst dissolved in a methanol solvent system, provided the transition metal complex is not transition metal carbonyl. The coordinating ligands can be selected from the group consisting of N-donor ligands, P-donor ligands, O-donor ligands, C-donor ligands, halogens and mixtures thereof.

  8. Arsenate stabilized Cu₂O nanoparticle catalyst for one-electron transfer reversible reaction.

    Science.gov (United States)

    Sahoo, Ramkrishna; Dutta, Soumen; Pradhan, Mukul; Ray, Chaiti; Roy, Anindita; Pal, Tarasankar; Pal, Anjali

    2014-05-14

    The befitting capping capabilities of AsO4(3-) provide a stable Cu2O nanocatalyst from a galvanic reaction between a Cu(II) precursor salt and As(0) nanoparticles. This stable Cu2O hydrosol appears to be a suitable catalyst for the one-electron transfer reversible redox reaction between Eosin Y and NaBH4. The progress of the reaction relates to three different kinetic stages. In the presence of the new catalyst the reversible redox reaction of Eosin Y in air shows a periodic color change providing a new crowd-pleasing demonstration, i.e. a "clock reaction".

  9. Microfoundations of Routines and Capabilities

    DEFF Research Database (Denmark)

    Felin, Teppo; Foss, Nicolai Juul; Heimriks, Koen H.

    We discuss the microfoundations of routines and capabilities, including why a microfoundations view is needed and how it may inform work on organizational and competitive heterogeneity. Building on extant research, we identify three primary categories of micro-level components underlying routines...

  10. Microfoundations of Routines and Capabilities

    DEFF Research Database (Denmark)

    Felin, Tippo; Foss, Nicolai Juul; Heimericks, Koen H.

    2012-01-01

    This article introduces the Special Issue and discusses the microfoundations of routines and capabilities, including why a microfoundations view is needed and how it may inform work on organizational and competitive heterogeneity. Building on extant research, we identify three primary categories ...

  11. Demonstration MTI/SAR capability

    NARCIS (Netherlands)

    Vries, F.P.P. de; Broek, A.C. van den; Otten, M.P.G.; Groot, J.S.; Steeghs, T.P.H.; Dekker, R.J.; Rossum, W.L. van

    2001-01-01

    The aim of this project is to demonstrate to the Dutch armed forces the capability of MTI (Moving Target Indicator) and SAR (Synthetic Aperture Radar). This is done with the Dutch PHARUS sensor. The sensor is used to demonstrate how a phased array antenna can be used as an MTI/SAR sensor

  12. Lifelong Learning: Capabilities and Aspirations

    Science.gov (United States)

    Ilieva-Trichkova, Petya

    2016-01-01

    The present paper discusses the potential of the capability approach in conceptualizing and understanding lifelong learning as an agency process, and explores its capacity to guide empirical studies on lifelong learning. It uses data for 20 countries from the Adult Education Survey (2007; 2011) and focuses on aspirations for lifelong learning. The…

  13. Production, innovation and service capabilities

    DEFF Research Database (Denmark)

    Slepniov, Dmitrij; Wæhrens, Brian Vejrum; Wu, Dong

    2012-01-01

    Fragmentation and global dispersion are among the most prominent characteristics of contemporary operations. Not only routine transactional tasks, but also more knowledge-intensive proprietary tasks are subjected to this trend. As a result of this, complex configurations of assets and capabilities...

  14. Capabilities and Well-being

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2008-01-01

    textabstractIntroduction The Capability Approach (CA) has been initiated and guided by Amartya Sen, since the 1980s, as an alternative to neoclassical welfare economics. The approach emerged gradually out of his rich critique of mainstream economics, in particular his dissatisfaction with

  15. Capability and Learning to Choose

    Science.gov (United States)

    LeBmann, Ortrud

    2009-01-01

    The Capability Approach (henceforth CA) is in the first place an approach to the evaluation of individual well-being and social welfare. Many disciplines refer to the CA, first and foremost welfare economics, development studies and political philosophy. Educational theory was not among the first disciplines that took notice of the CA, but has a…

  16. Research for new UAV capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.; Leadabrand, R.

    1996-07-01

    This paper discusses research for new Unmanned Aerial Vehicles (UAV) capabilities. Findings indicate that UAV performance could be greatly enhanced by modest research. Improved sensors and communications enhance near term cost effectiveness. Improved engines, platforms, and stealth improve long term effectiveness.

  17. Thermally Stable, Latent Olefin Metathesis Catalysts

    OpenAIRE

    Thomas, Renee M.; Fedorov, Alexey; Keitz, Benjamin K.; Grubbs, Robert H.

    2011-01-01

    Highly thermally stable N-aryl,N-alkyl N-heterocyclic carbene (NHC) ruthenium catalysts were designed and synthesized for latent olefin metathesis. These catalysts showed excellent latent behavior toward metathesis reactions, whereby the complexes were inactive at ambient temperature and initiated at elevated temperatures, a challenging property to achieve with second generation catalysts. A sterically hindered N-tert-butyl substituent on the NHC ligand of the ruthenium complex was found to i...

  18. Oxidation catalysts on alkaline earth supports

    Science.gov (United States)

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  19. Molecular catalysts structure and functional design

    CERN Document Server

    Gade, Lutz H

    2014-01-01

    Highlighting the key aspects and latest advances in the rapidly developing field of molecular catalysis, this book covers new strategies to investigate reaction mechanisms, the enhancement of the catalysts' selectivity and efficiency, as well as the rational design of well-defined molecular catalysts. The interdisciplinary author team with an excellent reputation within the community discusses experimental and theoretical studies, along with examples of improved catalysts, and their application in organic synthesis, biocatalysis, and supported organometallic catalysis. As a result, readers wil

  20. Next Generation Catalyst Engineering via Support Modification

    Science.gov (United States)

    2016-01-21

    performance of AT-treated MEAs is related to an improved interface between the catalyst and Nafion ionomer . Among potential explanations, this...Gennett, Ryan O’Hayre. Effect of Halide-Modified Model Carbon Supports on Catalyst Stability, ACS Applied Materials & Interfaces , (12 2012): 0...model carbon supports on catalyst stability”, ACS Appl. Mater. Interfaces , 4 (12), 6728-6734 (2012) 4) Demonstration of Improved Durability Using a

  1. Bifunctional cobalt F-T catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.G.; Coughlin, P.K.; Yang, C.L.; Rabo, J.A.

    1986-03-01

    Results on the catalytic screening of Fischer-Tropsch catalysts containing shape selective components are reported. Catalysts consist of promoted cobalt intimately contacted with Union Carbide molecular sieves and were tested using a Berty type internally recycled reactor. Methods of preparation, promoters and shape selective components were varied and aimed at improving catalyst performance. Catalysts were developed demonstrating high C/sub 5/ + yields with high olefin content and low methane production while maintaining stability under both low and high H/sub 2/:CO ratio conditions.

  2. Nitrogen oxides storage catalysts containing cobalt

    Science.gov (United States)

    Lauterbach, Jochen; Snively, Christopher M.; Vijay, Rohit; Hendershot, Reed; Feist, Ben

    2010-10-12

    Nitrogen oxides (NO.sub.x) storage catalysts comprising cobalt and barium with a lean NO.sub.x storage ratio of 1.3 or greater. The NO.sub.x storage catalysts can be used to reduce NO.sub.x emissions from diesel or gas combustion engines by contacting the catalysts with the exhaust gas from the engines. The NO.sub.x storage catalysts can be one of the active components of a catalytic converter, which is used to treat exhaust gas from such engines.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    , we report a more detailed catalytic study aimed at optimizing the catalyst performance. For this purpose, two series of mono and bimetallic Ni-Fe catalysts supported on MgAl2O4 and Al2O3, respectively, were prepared. All catalysts were tested in the CO methanation reaction in the temperature interval...

  4. Controlled Polymerization of Isoprene with Chromium-Based Metal-Organic Framework Catalysts: Switching from Cyclic to cis-1,4-Selectivity Depending on Activator.

    Science.gov (United States)

    Gao, Fei; Zhang, Li; Yu, Chao; Yan, Xinwen; Zhang, Shaowen; Li, Xiaofang

    2018-03-05

    Chromium-based metal-organic framework (MOF) Cr-MIL-100/101 activated by activator and aluminum trialkyl compound serve as unique, highly efficient heterogeneous single-site catalysts for the controlled polymerization of isoprene, which not only exhibit quasi-living nature in isoprene polymerization but also unprecedentedly switch from cyclic to cis-1,4-selectivity depending on the activator used to yield low molecular weight cyclic PIPs or extremely high molecular weight cis-1,4-PIPs. Such heterogeneous Cr-MOF catalysts can be recycled approximately five times. Based on nitrogen sorption isotherm tests and powder X-ray diffraction, a cationic mechanism is suggested, in which the polymerization takes place inside the open nanochannels of MOF catalysts and the space confinement effect of narrow open nanochannels originated from the coordination of PhNMe 2 from activator [PhNHMe 2 ][B(C 6 F 5 ) 4 ] with the multiple metal centers of MOF catalysts might give a rational explanation for such controlled adjustment on the PIP's structure and properties. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Human-Centered Design Capability

    Science.gov (United States)

    Fitts, David J.; Howard, Robert

    2009-01-01

    For NASA, human-centered design (HCD) seeks opportunities to mitigate the challenges of living and working in space in order to enhance human productivity and well-being. Direct design participation during the development stage is difficult, however, during project formulation, a HCD approach can lead to better more cost-effective products. HCD can also help a program enter the development stage with a clear vision for product acquisition. HCD tools for clarifying design intent are listed. To infuse HCD into the spaceflight lifecycle the Space and Life Sciences Directorate developed the Habitability Design Center. The Center has collaborated successfully with program and project design teams and with JSC's Engineering Directorate. This presentation discusses HCD capabilities and depicts the Center's design examples and capabilities.

  6. Determining your organization's 'risk capability'.

    Science.gov (United States)

    Hannah, Bill; Hancock, Melinda

    2014-05-01

    An assessment of a provider's level of risk capability should focus on three key elements: Business intelligence, including sophisticated analytical models that can offer insight into the expected cost and quality of care for a given population. Clinical enterprise maturity, marked by the ability to improve health outcomes and to manage utilization and costs to drive change. Revenue transformation, emphasizing the need for a revenue cycle platform that allows for risk acceptance and management and that provides incentives for performance against defined objectives.

  7. New Trends in Gold Catalysts

    Directory of Open Access Journals (Sweden)

    Leonarda F. Liotta

    2014-07-01

    Full Text Available Gold is an element that has fascinated mankind for millennia. The catalytic properties of gold have been a source of debate, due to its complete chemical inertness when in a bulk form, while it can oxidize CO at temperatures as low as ~200 K when in a nanocrystalline state, as discovered by Haruta in the late 1980s [1]. Since then, extensive activity in both applied and fundamental research on gold has been initiated. The importance of the catalysis by gold represents one of the fasted growing fields in science and is proven by the promising applications in several fields, such as green chemistry and environmental catalysis, in the synthesis of single-walled carbon nanotubes, as modifiers of Ni catalysts for methane steam and dry reforming reactions and in biological and electrochemistry applications. The range of reactions catalyzed by gold, as well as the suitability of different supports and the influence of the preparation conditions have been widely explored and optimized in applied research [2]. Gold catalysts appeared to be very different from the other noble metal-based catalysts, due to their marked dependence on the preparation method, which is crucial for the genesis of the catalytic activity. Several methods, including deposition-precipitation, chemical vapor deposition and cation adsorption, have been applied for the preparation of gold catalysts over reducible oxides, like TiO2. Among these methods, deposition-precipitation has been the most frequently employed method for Au loading, and it involves the use of tetrachloroauric (III acid as a precursor. On the other hand, the number of articles dealing with Au-loaded acidic supports is smaller than that on basic supports, possibly because the deposition of [AuCl4]− or [AuOHxCl4−x]− species on acidic supports is difficult, due to their very low point of zero charge. Despite this challenge, several groups have reported the use of acidic zeolites as supports for gold. Zeolites

  8. Exploration Medical Capability - Technology Watch

    Science.gov (United States)

    Krihak, Michael; Watkins, Sharmila; Barr, Yael; Barsten, Kristina; Fung, Paul; Baumann, David

    2011-01-01

    The objectives of the Technology Watch process are to identify emerging, high-impact technologies that augment current ExMC development efforts, and to work with academia, industry, and other government agencies to accelerate the development of medical care and research capabilities for the mitigation of potential health issues that could occur during space exploration missions. The establishment of collaborations with these entities is beneficial to technology development, assessment and/or insertion. Such collaborations also further NASA s goal to provide a safe and healthy environment for human exploration. The Tech Watch project addresses requirements and capabilities identified by knowledge and technology gaps that are derived from a discrete set of medical conditions that are most likely to occur on exploration missions. These gaps are addressed through technology readiness level assessments, market surveys, collaborations and distributed innovation opportunities. Ultimately, these gaps need to be closed with respect to exploration missions, and may be achieved through technology development projects. Information management is a key aspect to this process where Tech Watch related meetings, research articles, collaborations and partnerships are tracked by the HRP s Exploration Medical Capabilities (ExMC) Element. In 2011, ExMC will be introducing the Tech Watch external website and evidence wiki that will provide access to ExMC technology and knowledge gaps, technology needs and requirements documents.

  9. Judgmental Forecasting of Operational Capabilities

    DEFF Research Database (Denmark)

    Hallin, Carina Antonia; Tveterås, Sigbjørn; Andersen, Torben Juul

    This paper explores a new judgmental forecasting indicator, the Employee Sensed Operational Capabilities (ESOC). The purpose of the ESOC is to establish a practical prediction tool that can provide early signals about changes in financial performance by gauging frontline employees’ sensing of cha...... can predict financial performance. Monthly data were collected from frontline employees in three different companies during an 18-month period, and the initial results indicate that the ESOChas predictive power.......This paper explores a new judgmental forecasting indicator, the Employee Sensed Operational Capabilities (ESOC). The purpose of the ESOC is to establish a practical prediction tool that can provide early signals about changes in financial performance by gauging frontline employees’ sensing...... of changes in the firm’s operational capabilities. We present the first stage of the development of ESOC by applying a formative measurement approach to test the index in relation to financial performance and against an organizational commitment scale. We use distributed lag models to test whether the ESOC...

  10. Evolving Capabilities for Virtual Globes

    Science.gov (United States)

    Glennon, A.

    2006-12-01

    Though thin-client spatial visualization software like Google Earth and NASA World Wind enjoy widespread popularity, a common criticism is their general lack of analytical functionality. This concern, however, is rapidly being addressed; standard and advanced geographic information system (GIS) capabilities are being developed for virtual globes--though not centralized into a single implementation or software package. The innovation is mostly originating from the user community. Three such capabilities relevant to the earth science, education, and emergency management communities are modeling dynamic spatial phenomena, real-time data collection and visualization, and multi-input collaborative databases. Modeling dynamic spatial phenomena has been facilitated through joining virtual globe geometry definitions--like KML--to relational databases. Real-time data collection uses short scripts to transform user-contributed data into a format usable by virtual globe software. Similarly, collaborative data collection for virtual globes has become possible by dynamically referencing online, multi-person spreadsheets. Examples of these functions include mapping flows within a karst watershed, real-time disaster assessment and visualization, and a collaborative geyser eruption spatial decision support system. Virtual globe applications will continue to evolve further analytical capabilities, more temporal data handling, and from nano to intergalactic scales. This progression opens education and research avenues in all scientific disciplines.

  11. Highly Stable and Active Catalyst for Sabatier Reactions

    Science.gov (United States)

    Hu, Jianli; Brooks, Kriston P.

    2012-01-01

    Highly active Ru/TiO2 catalysts for Sabatier reaction have been developed. The catalysts have shown to be stable under repeated shutting down/startup conditions. When the Ru/TiO2 catalyst is coated on the engineered substrate Fe-CrAlY felt, activity enhancement is more than doubled when compared with an identically prepared engineered catalyst made from commercial Degussa catalyst. Also, bimetallic Ru-Rh/TiO2 catalysts show high activity at high throughput.

  12. Development of students learning capabilities and professional capabilities

    DEFF Research Database (Denmark)

    Ringtved, Ulla Lunde; Wahl, Christian; Belle, Gianna

    during their bachelor educations. Thetool aims at enhancing the development of students’ capabilities toself-initiate, self-regulate and self-assess their study activities.The tool uses the concept of collective intelligence as source formotivation and inspiration in self-initiating study activities...... as wellas self-assessing them. The tool is based on a heutagogical approachto support reflection on learning potential in these activities. Thisenhances the educational use of students self-initiated learningactivities by bringing visibility and evidence to them, and therebybringing value to the assessment...... of the study activities to benefitthe student as well as the educational institution....

  13. Waste cockle shell as natural catalyst for biodiesel production from jatropha oil

    Science.gov (United States)

    Hadi, Norulakmal Nor; Idrus, Nur Afini; Ghafar, Faridah; Salleh, Marmy Roshaidah Mohd

    2017-12-01

    Due to the increasing of industrialization and modernization of the world, the demand of petroleum has risen rapidly. The increasing demand for energy and environmental awareness has prompted many researches to embark on alternative fuel platforms that are environmentally acceptable. In this study, jatropha oil was used to produce biodiesel by a new transesterification routine in which cockle shell was used as source of heterogeneous catalyst. The investigation showed the catalyst that was calcined at temperature of 800 °C has the optimum capability to produce high yield. The highest yield of biodiesel production of 93.20 % were obtained by using 1.5 wt% of catalyst. The reaction was conducted at a temperature of 65 °C with the optimum methanol to oil ratio of 6:1. It was found that the physical properties of the biodiesel produced were significant to ASTM standard of fatty acid methyl ester (FAME).

  14. Methanol synthesis using a catalyst combination of alkali or alkaline earth salts and reduced copper chromite

    Science.gov (United States)

    Tierney, John W.; Wender, Irving; Palekar, Vishwesh M.

    1995-01-01

    The present invention relates to a novel route for the synthesis of methanol, and more specifically to the production of methanol by contacting synthesis gas under relatively mild conditions in a slurry phase with a catalyst combination comprising reduced copper chromite and basic alkali salts or alkaline earth salts. The present invention allows the synthesis of methanol to occur in the temperature range of approximately 100.degree.-160.degree. C. and the pressure range of 40-65 atm. The process produces methanol with up to 90% syngas conversion per pass and up to 95% methanol selectivity. The only major by-product is a small amount of easily separated methyl formate. Very small amounts of water, carbon dioxide and dimethyl ether are also produced. The present catalyst combination also is capable of tolerating fluctuations in the H.sub.2 /CO ratio without major deleterious effect on the reaction rate. Furthermore, carbon dioxide and water are also tolerated without substantial catalyst deactivation.

  15. Novel metalloporphyrin catalysts for the oxidation of hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Showalter, M.C.; Nenoff, T.M.; Shelnutt, J.A.

    1996-11-01

    Work was done for developing biomimetic oxidation catalysts. Two classes of metalloporphyrin catalysts were studied. The first class of catalysts studied were a novel series of highly substituted metalloporphyrins, the fluorinated iron dodecaphenylporphyrins. These homogeneous metalloporphyrin catalysts were screened for activity as catalysts in the oxidation of hydrocarbons by dioxygen. Results are discussed with respect to catalyst structural features. The second type of catalysts studied were heterogeneous catalysts consisting of metalloporphyrins applied to inorganic supports. Preliminary catalytic testing results with these materials are presented.

  16. European workshop on spent catalysts. Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    In 1999 and 2002 two well attended workshops on recycling, regeneration, reuse and disposal of spent catalysts took place in Frankfurt. This series has been continued in Berlin. The workshop was organized in collaboration with DGMK, the German Society for Petroleum and Coal Science and Technology. Contributions were in the following areas of catalyst deactivation: recycling of spent catalysts in chemical and petrochemical industry, recycling of precious metal catalysts and heterogenous base metal catalysts, legal aspects of transboundary movements, catalyst regeneration, quality control, slurry catalysts, commercial reactivation of hydrotreating catalysts. (uke)

  17. Catalyst and method for production of methylamines

    Science.gov (United States)

    Klier, Kamil; Herman, Richard G.; Vedage, Gamini A.

    1987-01-01

    This invention relates to an improved catalyst and method for the selective production of methylamines. More particularly, it is concerned with the preparation of stable highly active catalysts for producing methylamines by a catalytic reaction of ammonia or substituted amines and binary synthesis gas (CO+H.sub.2).

  18. Ligand iron catalysts for selective hydrogenation

    Science.gov (United States)

    Casey, Charles P.; Guan, Hairong

    2010-11-16

    Disclosed are iron ligand catalysts for selective hydrogenation of aldehydes, ketones and imines. A catalyst such as dicarbonyl iron hydride hydroxycyclopentadiene) complex uses the OH on the five member ring and hydrogen linked to the iron to facilitate hydrogenation reactions, particularly in the presence of hydrogen gas.

  19. Olefin polymerization over supported chromium oxide catalysts

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.

    1999-01-01

    Cr/SiO2 or Phillips-type catalysts are nowadays responsible for a large fraction of all polyethylene (HDPE and LLDPE) worldwide produced. In this review, several key-properties of Cr/SiO2 catalysts will be discussed in relation to their polymerization characteristics. It will be shown how the

  20. Investigation of vanadium catalyst regeneration stages

    International Nuclear Information System (INIS)

    Tsarev, Yu.V.; Il'in, A.P.; Shirokov, Yu.G.

    1995-01-01

    Regeneration stages of vanadium catalyst: dissolution of spent catalyst in alkaline solution of potassium vanadate, precipitation and aging of hydrosilica gel, which passed to solution, have been studied experimentally. The influence of the stages on final activity and thermal stability of regenerated contact masses has been considered. 10 refs., 4 figs., 2 tabs

  1. Behaviour of six sulphided iron hydroliquefaction catalysts

    International Nuclear Information System (INIS)

    Cook, P.S.; Cashion, J.D.; Bell, A.P.

    1994-01-01

    Five iron ore samples and a synthetic magnetite were added to Wandoan bituminous coal as hydroliquefaction catalysts. Catalyst transformations after sulphiding and after subsequent hydrogenation were analysed. The conversion efficiency increased with decreasing particle size or increased crystallographic disorder and showed that different catalytic mechanisms operate in the hydroliquefaction of brown and black coals. (orig.)

  2. Thin film hydrous metal oxide catalysts

    Science.gov (United States)

    Dosch, Robert G.; Stephens, Howard P.

    1995-01-01

    Thin film (metal oxide catalysts are prepared by 1) synthesis of a hydrous metal oxide, 2) deposition of the hydrous metal oxide upon an inert support surface, 3) ion exchange with catalytically active metals, and 4) activating the hydrous metal oxide catalysts.

  3. Magnetically retrievable catalysts for organic synthesis

    Science.gov (United States)

    The use of magnetic nanoparticles (MNPs) as a catalyst in organic synthesis has become a subject of intense investigation. The recovery of expensive catalysts after catalytic reaction and reusing it without losing its activity is an important feature in the sustainable process de...

  4. Post-metallocene catalysts for olefin polymerisation

    International Nuclear Information System (INIS)

    Bryliakov, Konstantin P

    2007-01-01

    The main types of post-metallocene catalysts for olefin polymerisation based on bis(imino), bis(imino)pyridyl, bis(phenoxyimino), bis(pyrrolylimino) and other complexes of transition metals developed in the last 10-15 years and having prospects for practical use are considered. Modern views on the mechanism of action of these catalysts are discussed.

  5. Post-metallocene catalysts for olefin polymerisation

    Energy Technology Data Exchange (ETDEWEB)

    Bryliakov, Konstantin P [G K Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences (Russian Federation)

    2007-03-31

    The main types of post-metallocene catalysts for olefin polymerisation based on bis(imino), bis(imino)pyridyl, bis(phenoxyimino), bis(pyrrolylimino) and other complexes of transition metals developed in the last 10-15 years and having prospects for practical use are considered. Modern views on the mechanism of action of these catalysts are discussed.

  6. Post-metallocene catalysts for olefin polymerisation

    Science.gov (United States)

    Bryliakov, Konstantin P.

    2007-03-01

    The main types of post-metallocene catalysts for olefin polymerisation based on bis(imino), bis(imino)pyridyl, bis(phenoxyimino), bis(pyrrolylimino) and other complexes of transition metals developed in the last 10-15 years and having prospects for practical use are considered. Modern views on the mechanism of action of these catalysts are discussed.

  7. Nanoparticular metal oxide/anatase catalysts

    DEFF Research Database (Denmark)

    2010-01-01

    the catalyst metai oxide is co-precipitated with the carrier metal oxide, which crystallization seeds are removed by combustion in a final calcining step. The present invention also concerns processes wherein the nanoparticular metal oxide catalysts of the invention are used, such as SCR (deNOx) reactions...

  8. Advances in Catalyst Deactivation and Regeneration

    Directory of Open Access Journals (Sweden)

    Calvin H. Bartholomew

    2015-06-01

    Full Text Available Catalyst deactivation, the loss over time of catalytic activity and/or selectivity, is a problem of great and continuing concern in the practice of industrial catalytic processes. Costs to industry for catalyst replacement and process shutdown total tens of billions of dollars per year. [...

  9. Advances in Catalyst Deactivation and Regeneration

    OpenAIRE

    Calvin H. Bartholomew; Morris D. Argyle

    2015-01-01

    Catalyst deactivation, the loss over time of catalytic activity and/or selectivity, is a problem of great and continuing concern in the practice of industrial catalytic processes. Costs to industry for catalyst replacement and process shutdown total tens of billions of dollars per year. [...

  10. Vanadyl phosphate catalysts in biodiesel production

    Energy Technology Data Exchange (ETDEWEB)

    Di Serio, M.; Cozzolino, M.; Tesser, R.; Santacesaria, E. [Universita degli studi di Napoli ' Federico II' , Dipartimento di Chimica, via Cintia 4, I-80126 Napoli (Italy); Patrono, P.; Pinzari, F. [CNR-IMIP Area della Ricerca di Roma, via Salaria, 00016 Monterotondo Scalo, Roma (Italy); Bonelli, B. [Politecnico di Torino, Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, C.so Duca degli Abruzzi 24, I-10129 Torino (Italy)

    2007-03-22

    The possibility of using vanadyl phosphate (VOP)-based catalysts in biodiesel production has been investigated. Vanadium phosphate catalysts resulted very active in the transesterification reaction of triglycerides with methanol, despite their low specific surface area. A slow deactivation of the catalysts has been experimentally detected under the reaction conditions, but the catalyst can easily be regenerated by calcination in air. The influence of the calcination treatment on the surface structure and, consequently, on its catalytic performances was deeply investigated. Both fresh and used catalysts were characterized by using several techniques, such as BET, X-ray diffraction (XRD), UV-vis diffuse reflectance (DRUV) and laser-Raman (LRS). The characterization results showed that the deactivation is due to a progressive reduction of vanadium (V) species from V{sup 5+} to V{sup 4+} and V{sup 3+} by methanol. By comparing the obtained performances of VOP catalysts with the ones of other heterogeneous catalysts reported by the literature, it is possible to conclude that VOP catalysts can already be used industrially for biodiesel production but their performances can probably be greatly improved in perspective. (author)

  11. Future trends in the refining catalyst market

    International Nuclear Information System (INIS)

    Silvy, Ricardo Prada

    2004-01-01

    The oil refining industry operation is analyzed in order to estimate the future catalyst market trends. The refining catalyst market corresponding to the main catalytic processes is estimated taking into account the following information: (1) the average refining capacity increases for the main catalytic processes since 1999, (2) the additional refining capacity due to future plans of construction and expansion of refineries and process units that will be added by 2005, and (3) the past refining catalyst market behavior. From this information, we have determined for the main catalytic processes a global average factor, expressed as processed oil barrels per dollar of catalyst. According to our estimates, the global refining catalyst market will increase from $2.32 billion in 2001 to about $2.65 billion in 2005 (3.6% annual growth). Hydrotreating, fluid catalytic cracking, hydrocracking and isomerization represent about 74% of the total catalyst market and will grow by about $34, $32, $11 and $2.5 million per year, respectively. However, naphtha reforming catalyst market will not grow during 2001-2005. Higher catalyst spending growth is expected for the North America region ($27.5 million per year)

  12. Transmission electron microscopy on live catalysts

    NARCIS (Netherlands)

    Bremmer, G.M.

    2017-01-01

    The dissertation describes TEM experiments on heterogeneous catalysts. Starting with characterization of (Ni/Co)MoS2 on Alumina and the effect of oxidation, and sequential resulfidation. After that, Co-based catalysts are used for high-resolution (S)TEM/EDX caracterization studies, and in situ

  13. Method for reactivating catalysts and a method for recycling supercritical fluids used to reactivate the catalysts

    Science.gov (United States)

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

    2008-08-05

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

  14. New catalysts for clean environment

    Energy Technology Data Exchange (ETDEWEB)

    Maijanen, A.; Hase, A. [eds.] [VTT Chemical Technology, Espoo (Finland)

    1996-12-31

    VTT launched a Research Programme on Chemical Reaction Mechanisms (CREAM) in 1993. The three-year programme (1993-1995) has focused on reaction mechanisms relevant to process industries and aimed at developing novel catalysts and biocatalysts for forest, food, and specialty chemicals industries as well as for energy production. The preliminary results of this programme have already been presented in the first symposium organized in Espoo in September 1994. To conclude the programme the second symposium is organized in Otaniemi, Espoo on January 29 - 30, 1996. Papers by 19 speakers and 17 poster presentations of the 1996 Symposium are included in this book. The Symposium consists of four sessions: Biotechnology for Natural Fibers Processing, New Biocatalysts, Catalysts for Clean Energy, and New Opportunities for Chemical Industry. The CREAM programme has tried to foresee solutions for the problems challenged by the public concern on environmental aspects, especially dealing with industrial processes and novel use of raw materials and energy. The programme has followed the basic routes that can lead to natural and simple solutions to develop processes in the fields of forest, food fine chemicals, and energy industry. This symposium presents the results of the programme to learn and further discuss together with the international experts that have been invited as keynote speakers. (author)

  15. Isobutane alkylation over solid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kozorezov, Y.I.; Lisin, V.I.

    1979-05-01

    Commercial alumina modified with 6Vertical Bar3< by wt boron trifluoride was active in isobutane alkylation with ethylene in a flow reactor at 5:1 isobutane-ethylene and 5-20 min reaction time. The reaction rate was first-order in ethylene and increased with increasing temperature (20/sup 0/-80/sup 0/C) and ethylene pressure (0.2-3 atm). The calculated activation energy was 8.4 kj. Kinetic data and the activity of tert.-butyl chloride, but not ethyl chloride as alkylating agents in place of ethylene suggested a carbonium-ion chain mechanism involving both surface and gas-phase reactions. The ethylene-based yield of the alkylate decreased from 132 to 41Vertical Bar3< by wt after nine hours on stream, and its bromine number increased from 0.2 to 1 g Br/sub 2//100 ml. This inhibition was attributed to adsorption on the active acidic sites of the reaction products, particularly C/sub 10//sup +/ olefins. Catalyst stabilization could probably be achieved by selecting an appropriate solvent that would continuously desorb the inhibiting products from the catalyst surface.

  16. Capability Development in an Offshoring Context

    DEFF Research Database (Denmark)

    Jaura, Manya

    Capability development can be defined as deliberate firm-level investment involving a search and learning process aimed at modifying or enhancing existing capabilities. Increasingly, firms are relocating advanced services to offshore locations resulting in the challenge of capability development...

  17. Summary of Sandia Laboratories technical capabilities

    International Nuclear Information System (INIS)

    1977-05-01

    The technical capabilities of Sandia Laboratories are detailed in a series of companion reports. In this summary the use of the capabilities in technical programs is outlined and the capabilities are summarized. 25 figures, 3 tables

  18. Nanostructured nonprecious metal catalysts for oxygen reduction reaction.

    Science.gov (United States)

    Wu, Gang; Zelenay, Piotr

    2013-08-20

    carbon nanostructures by catalyzing the decomposition of the nitrogen/carbon precursor. We can control the formation of different nanostructures during the synthesis of M-N-C catalysts. For example, in situ formed nitrogen-doped graphene-sheets can only be derived from polyaniline (PANI), probably due to structural similarities between the aromatic structures of PANI and graphene. Highly-graphitized carbon nanostructures may serve as a matrix for the formation of ORR-active groups with improved catalytic activity and durability, containing nitrogen and most probably also metal atoms. In the future, we will likely focus NPMC synthesis approaches on precise control of interactions between precursors of the metal and carbon/nitrogen during the heat treatment. The main purposes will be to maximize the number of active sites, optimize nitrogen doping levels, and generate morphologies capable of hosting active and stable ORR sites.

  19. Theoretical investigations of olefin metathesis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cundari, T.R.; Gordon, M.S. [North Dakota State Univ., Fargo, ND (United States)

    1992-01-01

    An ab initio analysis of the electronic structure of high-valent, transition-metal alkylidenes as models for olefin metathesis catalysts is presented. The catalyst models studied fall into three categories: {open_quotes}new{close_quotes} metathesis catalyst models-tetrahedral M(OH){sup 2}(XH)(CH{sub 2}) complexes; {open_quotes}old{close_quotes} metathesis catalyst models-tetrahedral MCl{sub 2}(Y)(CH{sub 2}) complexes and alkylidene-substituted Mo metathesis catalysts, Mo(OH){sub 2}(NH)(=C(H)Z). The effect on the bonding caused by modification of either the metal, ligands, or alkylidene substitutents is considered. 21 refs., 2 figs., 5 tabs.

  20. Developing a dispersant spraying capability

    Energy Technology Data Exchange (ETDEWEB)

    Gill, S.D.

    1979-01-01

    In developing a national dispersant spraying capability, the Canadian Coast Guard (CCG) has undertaken a modification program to enable the conventional offshore spraying gear to be mounted on almost any vessel of convenience. Smaller, more versatile inshore spraying vessels and pumps have been designed and built. With the popularization of concentrated dispersants, the inshore pumping equipment can be used aboard hovercraft for special application situations. A program of acquiring mobile dispersant storage tanks has been undertaken with auxiliary equipment that will facilitate the shipment of dispersants in bulk by air freight. Work also has commenced on extending the dispersant application program to include the CCG fleet of helicopters.

  1. PROGRAMS WITH DATA MINING CAPABILITIES

    Directory of Open Access Journals (Sweden)

    Ciobanu Dumitru

    2012-03-01

    Full Text Available The fact that the Internet has become a commodity in the world has created a framework for anew economy. Traditional businesses migrate to this new environment that offers many features and options atrelatively low prices. However competitiveness is fierce and successful Internet business is tied to rigorous use of allavailable information. The information is often hidden in data and for their retrieval is necessary to use softwarecapable of applying data mining algorithms and techniques. In this paper we want to review some of the programswith data mining capabilities currently available in this area.We also propose some classifications of this softwareto assist those who wish to use such software.

  2. Financial Capability of Austrian Households

    OpenAIRE

    Pirmin Fessler; Martin Schürz; Karin Wagner; Beat Weber

    2007-01-01

    Based on a survey by the Oesterreichische Nationalbank (OeNB) in 2004, this paper aims to assess Austrian households’ financial capability with respect to managing money, planning ahead financially, making financial choices and staying informed. People’s attitudes about money often depend on their education, income and age. A higher level of education, income and age tends to go hand in hand with a more positive financial attitude. The OeNB’s survey, however, revealed that, in the case of Aus...

  3. Developing A/E Capabilities

    International Nuclear Information System (INIS)

    Gonzalez, A.; Gurbindo, J.

    1987-01-01

    During the last few years, the methods used by EMPRESARIOS AGRUPADOS and INITEC to perform Architect-Engineering work in Spain for nuclear projects has undergone a process of significant change in project management and engineering approaches. Specific practical examples of management techniques and design practices which represent a good record of results will be discussed. They are identified as areas of special interest in developing A/E capabilities for nuclear projects . Command of these areas should produce major payoffs in local participation and contribute to achieving real nuclear engineering capabities in the country. (author)

  4. An Alumina-Supported Ni-La-Based Catalyst for Producing Synthetic Natural Gas

    Directory of Open Access Journals (Sweden)

    Daniel E. Rivero-Mendoza

    2016-10-01

    Full Text Available LaNi5, known for its hydrogen storage capability, was adapted to the form of a metal oxide-supported (γ-Al2O3 catalyst and its performance for the Sabatier reaction assessed. The 20 wt % La-Ni/γ-Al2O3 particles were prepared via solution combustion synthesis (SCS and exhibited good catalytic activity, achieving a CO2 conversion of 75% with a high CH4 selectivity (98% at 1 atm and 300 °C. Characteristics of the La-Ni/γ-Al2O3 catalyst were identified at various stages of the catalytic process (as-prepared, activated, and post-reaction and in-situ DRIFTS was used to probe the reaction mechanism. The as-prepared catalyst contained amorphous surface La–Ni spinels with particle sizes <6 nm. The reduction process altered the catalyst make-up where, despite the reducing conditions, Ni2+-based particles with diameters between 4 and 20 nm decorated with LaOx moieties were produced. However, the post-reaction catalyst had particle sizes of 4–9 nm and comprised metallic Ni, with the LaOx decoration reverting to a form akin to the as-prepared catalyst. DRIFTS analysis indicated that formates and adsorbed CO species were present on the catalyst surface during the reaction, implying the reaction proceeded via a H2-assisted and sequential CO2 dissociation to C and O. These were then rapidly hydrogenated into CH4 and H2O.

  5. High-activity PtRuPd/C catalyst for direct dimethyl ether fuel cells.

    Science.gov (United States)

    Li, Qing; Wen, Xiaodong; Wu, Gang; Chung, Hoon T; Gao, Rui; Zelenay, Piotr

    2015-06-22

    Dimethyl ether (DME) has been considered as a promising alternative fuel for direct-feed fuel cells but lack of an efficient DME oxidation electrocatalyst has remained the challenge for the commercialization of the direct DME fuel cell. The commonly studied binary PtRu catalyst shows much lower activity in DME than methanol oxidation. In this work, guided by density functional theory (DFT) calculation, a ternary carbon-supported PtRuPd catalyst was designed and synthesized for DME electrooxidation. DFT calculations indicated that Pd in the ternary PtRuPd catalyst is capable of significantly decreasing the activation energy of the CO and CH bond scission during the oxidation process. As evidenced by both electrochemical measurements in an aqueous electrolyte and polymer-electrolyte fuel cell testing, the ternary catalyst shows much higher activity (two-fold enhancement at 0.5 V in fuel cells) than the state-of-the-art binary Pt50 Ru50 /C catalyst (HiSPEC 12100). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. High quality syngas production from microwave pyrolysis of rice husk with char-supported metallic catalysts.

    Science.gov (United States)

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan

    2015-09-01

    This study aimed to obtain the maximum possible gas yield and the high quality syngas production from microwave pyrolysis of rice husk with rice husk char and rice husk char-supported metallic (Ni, Fe and Cu) catalysts. The rice husk char-supported metallic catalysts had developed pore structure and catalytic activity for gas productions and tar conversion. The temperature-rising characteristic, product yields, properties of gas products and tar conversion mechanisms were investigated. It was found that three rice husk char-supported metallic catalysts improved the microwave absorption capability and increased heating rate and final temperature. Rice husk char-supported Ni catalyst presented most effective effects on gas production, e.g. the gas yield is 53.9%, and the volume concentration of desired syngas is 69.96%. Rice husk char-supported Ni and Fe catalysts played pivotal roles in tar conversion that less heavy compounds can be detected along with the reduction of organic compound number. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Detection capabilities. Some historical footnotes

    International Nuclear Information System (INIS)

    Currie, L.A.

    2017-01-01

    Part I Summary of relevant topics from 1923 to present-including: Currie (Anal Chem 40:586-593, 1968) detection concepts and capabilities; International detection and uncertainty standards; Failure of classical 14 C dating and birth of new scientific disciplines; Exploratory nuclear data analysis of 85 Kr monitors found coincident with the collapse of the Iron Curtain (1989); Faulty statistics proved responsible for mistaken assertions that Currie's LC yields excessive false positives; Low-level counting and AMS for atmospheric 37 Ar and µmolar fossil/biomass carbon in the environment; Erroneous assumption that our low-level background is a Poisson Process, linked to ∼8 % spurious anticoincidence events. Part II. Exact treatment of bivariate Poisson data-solved in 1930s by Przyborowski and Wilenski, Krakow University, for detecting extreme trace amounts of a malicious contaminant (dodder) in high purity seed standards. We adapted their treatment to detection capabilities in ultra-low-level nuclear counting. The timing of their work had great historical significance, marking the start of World War II, with the invasion of Poland (1939). (author)

  8. Development of group IV molecular catalysts for high temperature ethylene-α-olefin copolymerization reactions.

    Science.gov (United States)

    Klosin, Jerzy; Fontaine, Philip P; Figueroa, Ruth

    2015-07-21

    This Account describes our research related to the development of molecular catalysts for solution phase olefin polymerization. Specifically, a series of constrained geometry and nonmetallocene (imino-amido-type) complexes were developed for high temperature olefin polymerization reactions. We have discovered many highly active catalysts that are capable of operating at temperatures above 120 °C and producing copolymers with a useful range of molecular weights (from medium to ultrahigh depending on precatalyst identity and polymerization conditions) and α-olefin incorporation capability. Constrained geometry catalysts (CGCs) exhibit very high activities and are capable of producing a variety of copolymers including ethylene-propylene and ethylene-1-octene copolymers at high reactor temperatures. Importantly, CGCs have much higher reactivity toward α-olefins than classical Ziegler-Natta catalysts, thus allowing for the production of copolymers with any desired level of comonomer. In search of catalysts with improved performance, we discovered 3-amino-substituted indenyl-based CGCs that exhibit the highest activity and produce copolymers with the highest molecular weight within this family of catalysts. Phenanthrenyl-based CGCs were found to be outstanding catalysts for the effective production of high styrene content ethylene-styrene copolymers under industrially relevant conditions. In contrast to CGC ligands, imino-amido-type ligands are bidentate and monoionic, leading to the use of trialkyl group IV precatalysts. The thermal instability of imino-amido complexes was addressed by the development of imino-enamido and amidoquinoline complexes, which are not only thermally very robust, but also produce copolymers with higher molecular weights, and exhibit improved α-olefin incorporation. Imido-amido and imino-enamido catalysts undergo facile chain transfer reactions with metal alkyls, as evidenced by a sharp decrease in polymer molecular weight when the

  9. Fluidised bed catalytic pyrolysis of scrap tyres: influence of catalyst:tyre ratio and catalyst temperature.

    Science.gov (United States)

    Williams, Paul T; Brindle, Alexander J

    2002-12-01

    Pyrolysis with on-line Zeolite catalysis of scrap tyres was undertaken in a fluidised bed reactor with the aim of maximising the production of higher value single ring aromatic hydrocarbons in the derived oil. Experiments were carried out in relation to the ratio of the catalyst to tyre feedstock and the temperature of the catalyst bed. Two Zeolite catalysts were examined, a Y-type Zeolite catalyst and Zeolite ZSM-5 catalyst of differing pore size and surface activity. The composition of the oils derived from the uncatalysed fluidised bed pyrolysis of tyres showed that benzene concentration was 0.2 wt%, toluene concentration was 0.8 wt%, o-xylene was 0.3 wt%, m/p-xylenes were 1.8 wt% and limonene was 4.3 wt%. Benzene, toluene and xylenes present in the oils showed a significant increase in the presence of both of the catalysts. The maximum concentrations of these chemicals for the Y-Zeolite (CBV-400) catalyst was 1 wt% for benzene, 8wt% for toluene, 3 wt% for o-xylene and 8.5 wt% for m/p-xylenes, produced at a catalyst:tyre ratio of 1.5. There was less influence of catalyst temperature on the yield of benzene, toluene and xylenes, however, increasing the temperature of the catalyst resulted in a marked decrease in limonene concentration. The Y-type Zeolite catalyst produced significantly higher concentrations of benzene, toluene and xylenes which was attributed to the larger pore size and higher surface acidity of the Y-Zeolite catalyst compared to the Zeolite ZSM-5 catalyst.

  10. Catalysts, Protection Layers, and Semiconductors

    DEFF Research Database (Denmark)

    Chorkendorff, Ib

    2015-01-01

    Hydrogen is the simplest solar fuel to produce and in this presentation we shall give a short overview of the pros and cons of various tandem devices [1]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either...... acid or alkaline conditions. Since most relevant semiconductors are very prone to corrosion the advantage of using buried junctions and using protection layers offering shall be discussed [2-4]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers...... and how their stability may be evaluated [5, 6]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent examples under both alkaline and acidic conditions. Si is a very good low band gap semiconductor and by using TiO2 as a protection...

  11. Fundamental investigations of catalyst nanoparticles

    DEFF Research Database (Denmark)

    Elkjær, Christian Fink

    different topics, each related to different aspects of nanoparticle dynamics and catalysis. The first topic is the reduction of a homogeneous solid state precursor to form the catalytically active phase which is metal nanoparticles on an inert support. Here, we have reduced Cu phyllosilicate to Cu on silica......Heterogeneous catalysis, the conversion of chemicals by the use of a suitable solid state catalyst, is a very important technology in modern society and it is involved in the production of up to 90% of all chemicals. Catalysis has in this way played a significant role in the technological...... and economic development in the 20th century. There is however a downside to this development and we are seeing significant pollution and pressure on resources. Catalysis therefore has an increasingly important role in limiting pollution and optimizing the use of resources. This development will depend on our...

  12. Sulfur Resistance of Pt-W Catalysts

    Directory of Open Access Journals (Sweden)

    Carolina P. Betti

    2013-01-01

    Full Text Available The sulfur resistance of low-loaded monometallic Pt catalysts and bimetallic Pt-W catalysts during the partial selective hydrogenation of styrene, a model compound of Pygas streams, was studied. The effect of metal impregnation sequence on the activity and selectivity was also evaluated. Catalysts were characterized by ICP, TPR, XRD, and XPS techniques. Catalytic tests with sulfur-free and sulfur-doped feeds were performed. All catalysts showed high selectivities (>98% to ethylbenzene. Activity differences between the catalysts were mainly attributed to electronic effects due to the presence of different electron-rich species of Pt0 and electron-deficient species of Ptδ+. Pt0 promotes the cleavage of H2 while Ptδ+ the adsorption of styrene. The catalyst successively impregnated with W and Pt (WPt/Al was more active and sulfur resistant than the catalyst prepared with an inverse impregnation order (PtW/Al. The higher poison resistance of WPt/Al was attributed to both steric and electronic effects.

  13. Novel Fischer-Tropsch catalysts

    Science.gov (United States)

    Vollhardt, Kurt P. C.; Perkins, Patrick

    1980-01-01

    Novel polymer-supported metal complexes of the formula: PS --R Me(CO).sub.n H.sub.m where: PS represents a divinylbenzene crosslinked polystyrene in which the divinylbenzene crosslinking is greater than 1% and less than about 18%; R represents a cycloalkadienyl radical of 4 through 6 carbon atoms; Me represents a Group VIII metal; CO represents a carbonyl radical; H represents hydrogen; n represents an integer varying from 0 through 3; m represents an integer varying from 0 through 2 inclusively with the further provision that 2n+m must total 18 when added to the electrons in R and Me, or n+m must total 0; are prepared by: brominating PS --H by treating same with bromine in the presence of a thallium salt in a partially or fully halogenated solvent to form PS --Br; treating said PS --Br so produced with a lithium alkyl of 1 through 12 carbon atoms in an aromatic solvent to produce PS --Li; substituting said PS-- Li so produced by reaction with a 2-cycloalkenone of 4 to 6 carbon atoms in the presence of an ether solvent and using a water work-up to form a cycloalkenylalcohol-substituted PS ; dehydrating said alcohol so produced by heating under a vacuum to produce a cycloalkadienyl-substituted PS ; reacting the cycloalkadienyl-substituted PS with metal carbonyl in the presence of a partially or fully halogenated hydrocarbon, aromatic hydrocarbon of 6 through 8 carbon atoms, ethers, or esters of 4 through 10 carbon atoms as a solvent to produce a polystyrene-supported cycloalkadienyl metal carbonyl. The novel compounds 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.

  14. Professionals and Public Good Capabilities

    Directory of Open Access Journals (Sweden)

    Melanie Walker

    2015-12-01

    Full Text Available Martha Nussbaum (2011 reminds us that, all over the world people are struggling for a life that is fully human - a life worthy of human dignity. Purely income-based and preference-based evaluations, as Sen (1999 argues, do not adequately capture what it means for each person to have quality of life. There are other things that make life good for a person, including access to publicly provided professional services. The question then is what version of education inflects more towards the intrinsic and transformational possibilities of professional work and contributions to decent societies? This paper suggests that we need a normative approach to professional education and professionalism; it is not the case that any old version will do. We also need normative criteria to move beyond social critique and to overcome a merely defensive attitude and to give a positive definition to the potential achievements of the professions. Moreover universities are connected to society, most especially through the professionals they educate; it is reasonable in our contemporary world to educate professional graduates to be in a position to alleviate inequalities, and to have the knowledge, skills and values to be able to do so. To make this case, we draw on the human capabilities approach of Sen (1999, 2009 and Nussbaum (2000, 2011 to conceptualise professional education for the public good as an ally of the struggles of people living in poverty and experiencing inequalities, expanding the well-being of people to be and to do in ways they have reason to value – to be mobile, cared for, respected, and so on. In particular we are interested in which human capabilities and functionings are most needed for a professional practice and professionalism that can contribute to transformative social change and how professional development is enabled via pedagogical arrangements.

  15. Amartya Sen's Capability Approach and Education

    Science.gov (United States)

    Walker, Melanie

    2005-01-01

    The human capabilities approach developed by the economist Amartya Sen links development, quality of life and freedom. This article explores the key ideas in the capability approach of: capability, functioning, agency, human diversity and public participation in generating valued capabilities. It then considers how these ideas relate specifically…

  16. Dates in the development of catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Simon

    1943-05-20

    A chronological listing is presented of the dates on which various I. G. Farbenindustrie catalysts were first used. In most cases the entries gave compositions and some hints at the methods of preparation of the catalysts as well as the code numbers for the catalysts. The listing started in December, 1924, and extended throught August, 1941. Some of the more important catalysts were the following: 5058, tungsten disulfide (WS/sub 2/), produced from the thio salt by dry decomposition (1930); 6434, a diluted mixture of hydrogen fluoride-treated ''Terrana'' and 10% WS/sub 2/ (1935); 6719, a prehydrogenation catalyst of 75 parts ferrous sulfide (FeS), 22 parts WS/sub 2/, and 3 parts nickel monosulfide (NiS) (1937); 7019, an aromatization catalyst of 100 parts primry coal, 15 parts chromic oxide (Cr/sub 2/O/sub 3/), and 5 parts vanadium sesquioxide (V/sub 2/O/sub 3/) (1938); 7360, a DHD catalyst of activated alumina (Al/sub 2/O/sub 3/) and 55 g/l molybdenum trioxide (MoO/sub 3/) (1939); 7846, a prehydrogenated catalyst, a sulfonated mixture of activated alumina, 100 g/l MoO/sub 3/, and 30 g/l nickel sesquioxide (Ni/sub 2/O/sub 3/) (1940); and 8376 W, a prehydrogenation catalyst, a sulfonated mixture of activated alumina, 250 g/l tungsten trioxide (WO/sub 3/), and 50 g/l Ni/sub 2/O/sub 3/ (1941). Other caalysts given included numbers 1724, 2365, 2473, 2500, 3510, 3884, 5053, 5676, 6525, and 6561. Compounds used other than those mentioned above included molybdenum disulfide (MoS/sub 2/), zinc sulfide (ZnS), zinc oxide (ZnO), and magnesium oxide (MgO).

  17. Organizational Economics of Capability and Heterogeneity

    DEFF Research Database (Denmark)

    Argyres, Nicholas S.; Felin, Teppo; Foss, Nicolai Juul

    2012-01-01

    For decades, the literatures on firm capabilities and organizational economics have been at odds with each other, specifically relative to explaining organizational boundaries and heterogeneity. We briefly trace the history of the relationship between the capabilities literature and organizational...... economics, and we point to the dominance of a “capabilities first” logic in this relationship. We argue that capabilities considerations are inherently intertwined with questions about organizational boundaries and internal organization, and we use this point to respond to the prevalent capabilities first...... logic. We offer an integrative research agenda that focuses first on the governance of capabilities and then on the capability of governance....

  18. Investigation of activity and selectivity of redox catalysts in oxidative ...

    African Journals Online (AJOL)

    In this study, oxidative coupling of methane on Redox catalysts in fluidized bed reactor was investigated. For this purpose, the catalyst Mn-Na2WO4/SiO2 was selected as a Redox catalyst. In order to investigate this catalyst, transient state experiments were designed and performed. Then, the different reaction conditions on ...

  19. 40 CFR 90.427 - Catalyst thermal stress resistance evaluation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress resistance... Gaseous Exhaust Test Procedures § 90.427 Catalyst thermal stress resistance evaluation. (a) The purpose of... catalyst conversion efficiency for Phase 1 engines. The thermal stress is imposed on the test catalyst by...

  20. Bio-oil hydrodeoxygenation catalysts produced using strong electrostatic adsorption

    Science.gov (United States)

    We synthesized hydrothermally stable metal catalysts with controlled particle size and distribution, with the goal of determining which catalyst(s) can selectively catalyze the production of aromatics from bio-oil (from pyrolysis of biomass). Both precious and base transition metal catalysts (Ru, Pt...

  1. Towards the computational design of solid catalysts

    DEFF Research Database (Denmark)

    Nørskov, Jens Kehlet; Bligaard, Thomas; Rossmeisl, Jan

    2009-01-01

    Over the past decade the theoretical description of surface reactions has undergone a radical development. Advances in density functional theory mean it is now possible to describe catalytic reactions at surfaces with the detail and accuracy required for computational results to compare favourably...... with experiments. Theoretical methods can be used to describe surface chemical reactions in detail and to understand variations in catalytic activity from one catalyst to another. Here, we review the first steps towards using computational methods to design new catalysts. Examples include screening for catalysts...

  2. deNOx catalysts for biomass combustion

    DEFF Research Database (Denmark)

    Kristensen, Steffen Buus

    The present thesis revolves around the challenges involved in removal of nitrogen oxides in biomass fired power plants. Nitrogen oxides are unwanted byproducts formed to some extent during almost any combustion. In coal fired plants these byproducts are removed by selective catalytic reduction......, however the alkali in biomass complicate matters. Alkali in biomass severely deactivates the catalyst used for the selective catalytic reduction in matter of weeks, hence a more alkali resistant catalyst is needed. In the thesis a solution to the problem is presented, the nano particle deNOx catalyst...

  3. Catalyst for hydrogen-amine D exchange

    International Nuclear Information System (INIS)

    Holtslander, W.J.; Johnson, R.E.

    1976-01-01

    A process is claimed for deuterium isotopic enrichment (suitable for use in heavy water production) by amine-hydrogen exchange in which the exchange catalyst comprises a mixture of alkyl amides of two metals selected from the group consisting of the alkali metals. Catalyst mixtures comprising at least one of the alkali amides of lithium and potassium are preferred. At least one of the following benefits are obtained: decreased hydride formation, decreased thermal decomposition of alkyl amide, increased catalyst solubility in the amine phase, and increased exchange efficiency. 11 claims

  4. In-situ hydrodeoxygenation of phenol by supported Ni catalyst-explanation for catalyst performance

    DEFF Research Database (Denmark)

    Wang, Ze; Zeng, Ying; Lin, Weigang

    2017-01-01

    In-situ hydrodeoxygenation of phenol with aqueous hydrogen donor over supported Ni catalyst was investigated. The supported Ni catalysts exerted very poor performance, if formic acid was used as the hydrogen donor. Catalyst modification by loading K, Na, Mg or La salt could not make the catalyst ...... products of cyclohexanone and cyclohexanol. The better effect of methanol enlightened the application of the supported Ni catalyst in in-situ hydrodeoxygenation of phenol....... performance improved. If gaseous hydrogen was used as the hydrogen source the activity of Ni/Al2O3 was pretty high. CO2 was found poisonous to the catalysis, due to the competitive adoption of phenol with CO2. If formic acid was replaced by methanol, the catalyst performance improved remarkably, with major...

  5. Supported catalyst systems and method of making biodiesel products using such catalysts

    Science.gov (United States)

    Kim, Manhoe; Yan, Shuli; Salley, Steven O.; Ng, K. Y. Simon

    2015-10-20

    A heterogeneous catalyst system, a method of preparing the catalyst system and a method of forming a biodiesel product via transesterification reactions using the catalyst system is disclosed. The catalyst system according to one aspect of the present disclosure represents a class of supported mixed metal oxides that include at least calcium oxide and another metal oxide deposited on a lanthanum oxide or cerium oxide support. Preferably, the catalysts include CaO--CeO.sub.2ZLa.sub.2O.sub.3 or CaO--La.sub.2O.sub.3/CeO.sub.2. Optionally, the catalyst may further include additional metal oxides, such as CaO--La.sub.2O.sub.3--GdOxZLa.sub.2O.sub.3.

  6. Graphene-derived Fe/Co-N-C catalyst in direct methanol fuel cells: Effects of the methanol concentration and ionomer content on cell performance

    Science.gov (United States)

    Park, Jong Cheol; Choi, Chang Hyuck

    2017-08-01

    Non-precious metal catalysts (typically Fe(Co)-N-C catalysts) have been widely investigated for use as cost-effective cathode materials in low temperature fuel cells. Despite the high oxygen reduction activity and methanol-tolerance of graphene-based Fe(Co)-N-C catalysts in an acidic medium, their use in direct methanol fuel cells (DMFCs) has not yet been successfully implemented, and only a few studies have investigated this topic. Herein, we synthesized a nano-sized graphene-derived Fe/Co-N-C catalyst by physical ball-milling and a subsequent chemical modification of the graphene oxide. Twelve membrane-electrode-assemblies are fabricated with various cathode compositions to determine the effects of the methanol concentration, ionomer (i.e. Nafion) content, and catalyst loading on the DMFC performance. The results show that a graphene-based catalyst is capable of tolerating a highly-concentrated methanol feed up to 10.0 M. The optimized electrode composition has an ionomer content and catalyst loading of 66.7 wt% and 5.0 mg cm-2, respectively. The highest maximum power density is ca. 32 mW cm-2 with a relatively low PtRu content (2 mgPtRu cm-2). This study overcomes the drawbacks of conventional graphene-based electrodes using a nano-sized graphene-based catalyst and further shows the feasibility of their potential applications in DMFC systems.

  7. Novel Anode Catalyst for Direct Methanol Fuel Cells

    OpenAIRE

    Basri, S.; Kamarudin, S. K.; Daud, W. R. W.; Yaakob, Z.; Kadhum, A. A. H.

    2014-01-01

    PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs) but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni) and iron (Fe). Multiwalled carbon nanotubes (MWCNTs) are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX), X-ray diffracti...

  8. Bi-metallic catalysts, methods of making, and uses thereof

    KAUST Repository

    Basset, Jean-Marie

    2017-01-19

    Provided herein are bi-metallic catalysts, methods of making, and uses thereof. In some embodiments, the bi-metallic catalyst contains two different metal catalysts that can be used in hydrocarbon metathesis reactions, in some embodiments, the methods of making the bi-metallic catalysts can include two steps utilizing a surface organometallic chemistry approach in which the two different metal catalysts are sequentially grafted onto a support.

  9. Preparative characteristics of hydrophobic polymer catalyst for the tritium removal

    International Nuclear Information System (INIS)

    Kang, Hee Suk; Choi, H. J.; Lee, H. S.; Ahn, D. H.; Kim, K. R.; Paek, S. W.; Paek, S. W.; Kim, J. G.; Chung, H. S.

    2001-05-01

    The optimum method for the fabrication of hydrophobic catalyst was selected and the apparatuses for the preparation of catalyst support with high yield was developed for the large scale production. Also, we summarized the method of improving the physical property of the catalyst support, the loading characteristics of Pt metal as a catalyst, and the characteristics of the apparatus for the fabrication of the catalysts on a large scale

  10. OPSAID improvements and capabilities report.

    Energy Technology Data Exchange (ETDEWEB)

    Halbgewachs, Ronald D.; Chavez, Adrian R.

    2011-08-01

    Process Control System (PCS) and Industrial Control System (ICS) security is critical to our national security. But there are a number of technological, economic, and educational impediments to PCS owners implementing effective security on their systems. Sandia National Laboratories has performed the research and development of the OPSAID (Open PCS Security Architecture for Interoperable Design), a project sponsored by the US Department of Energy Office of Electricity Delivery and Energy Reliability (DOE/OE), to address this issue. OPSAID is an open-source architecture for PCS/ICS security that provides a design basis for vendors to build add-on security devices for legacy systems, while providing a path forward for the development of inherently-secure PCS elements in the future. Using standardized hardware, a proof-of-concept prototype system was also developed. This report describes the improvements and capabilities that have been added to OPSAID since an initial report was released. Testing and validation of this architecture has been conducted in another project, Lemnos Interoperable Security Project, sponsored by DOE/OE and managed by the National Energy Technology Laboratory (NETL).

  11. Raman spectrometer with microprobe capability

    Science.gov (United States)

    Boyd, J. T.; Jackson, H. E.

    1986-01-01

    This report describes the results of this equipment grant funded as a part of the Department of Defense (DOD) University Research Instrumentation Program. This grant funded the purchase of a Raman spectrometer with microprobe capability having resolution of 1.0 micron. This report describes the equipment selecting decision, the configuration of the instrument selected, and some experimental results. The experimental results include Raman spectra used in characterization of laser recrystallized silicon and ion implanted regions in semi-insulating GaAs. The Raman microprobe can be used to characterize the effects of substrate temperature, beam power density and shape, beam scan speed and direction, deposition rate, substrate seeding, and polysilicon encapsulation schemes both near and away from grain boundaries. The frequency shift and the peak width of the Raman scattering from the triply degenerate zone center phonon in Si allow determination of the strain in the grains of laser recrystallized polysilicon. Reducing these strains will allow us to achieve large single grains of device quality.

  12. System Code Models and Capabilities

    International Nuclear Information System (INIS)

    Bestion, D.

    2008-01-01

    System thermalhydraulic codes such as RELAP, TRACE, CATHARE or ATHLET are now commonly used for reactor transient simulations. The whole methodology of code development is described including the derivation of the system of equations, the analysis of experimental data to obtain closure relation and the validation process. The characteristics of the models are briefly presented starting with the basic assumptions, the system of equations and the derivation of closure relationships. An extensive work was devoted during the last three decades to the improvement and validation of these models, which resulted in some homogenisation of the different codes although separately developed. The so called two-fluid model is the common basis of these codes and it is shown how it can describe both thermal and mechanical nonequilibrium. A review of some important physical models allows to illustrate the main capabilities and limitations of system codes. Attention is drawn on the role of flow regime maps, on the various methods for developing closure laws, on the role of interfacial area and turbulence on interfacial and wall transfers. More details are given for interfacial friction laws and their relation with drift flux models. Prediction of chocked flow and CFFL is also addressed. Based on some limitations of the present generation of codes, perspectives for future are drawn.

  13. Atmospheric Release Advisory Capability (ARAC)

    International Nuclear Information System (INIS)

    Dickerson, M.H.

    1975-01-01

    The chief purpose of ARAC data acquisition program is to provide site officials, who are responsible for ensuring maximum health protection for the endangered site personnel and public, with estimates of the effects of atmospheric releases of hazardous material as rapidly and accurately as possible. ARAC is in the initial stages of being implemented and is therefore susceptible to changes before it reaches its final form. However the concept of ARAC is fully developed and was successfully demonstrated during a feasibility study conducted in June 1974, as a joint effort between the Savannah River Laboratory (SRL) and Lawrence Livermore Laboratory (LLL). Additional tests between SRL and LLL are scheduled for December 1975. While the immediate goal is the application of ARAC to assist a limited number of ERDA sites, the system is designed with sufficient flexibility to permit expanding the service to a large number of sites. Success in ARAC application should provide nuclear facilities with a means to handle better the urgent questions concerning the potential accidental hazards from atmospheric releases in addition to providing the sites with a capability to assess the effort of their normal operations

  14. Oxidation catalysts and process for preparing same

    International Nuclear Information System (INIS)

    1980-01-01

    Compounds particularly suitable as oxidation catalysis are described, comprising specified amounts of uranium, antimony and tin as oxides. Processes for making and using the catalysts are described. (U.K.)

  15. Environmentally benign catalysts for clean organic reactions

    CERN Document Server

    Patel, Anjali

    2013-01-01

    Heterogeneous catalysis attracts researchers and industry because it satisfies most of green chemistry's requirements. Emphasizing the development of third generation catalysts, this book surveys trends and opportunities in academic and industrial research.

  16. Stereogenic-Only-at-Metal Asymmetric Catalysts.

    Science.gov (United States)

    Zhang, Lilu; Meggers, Eric

    2017-09-19

    Chirality is an essential feature of asymmetric catalysts. This review summarizes asymmetric catalysts that derive their chirality exclusively from stereogenic metal centers. Reported chiral-at-metal catalysts can be divided into two classes, namely, inert metal complexes, in which the metal fulfills a purely structural role, so catalysis is mediated entirely through the ligand sphere, and reactive metal complexes. The latter are particularly appealing because structural simplicity (only achiral ligands) is combined with the prospect of particularly effective asymmetric induction (direct contact of the substrate with the chiral metal center). Challenges and solutions for the design of such reactive stereogenic-only-at-metal asymmetric catalysts are discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Evaluation of Low Temperature CO Removal Catalysts

    Science.gov (United States)

    Monje, Oscar

    2015-01-01

    CO removal from spacecraft gas streams was evaluated for three commercial, low temperature oxidation catalysts: Carulite 300, Sofnocat 423, and Hamilton Sundstrand Pt1. The catalysts were challenged with CO concentrations (1-100 ppm) under dry and wet (50% humidity) conditions using 2-3 % O2. CO removal and CO2 concentration were measured at constant feed composition using a FTIR. Water vapor affected the CO conversion of each catalyst differently. An initial screening found that Caulite 300 could not operate in humid conditions. The presence of water vapor affected CO conversion of Sofnocat 423 for challenge concentrations below 40 ppm. The conversion of CO by Sofnocat 423 was 80% at CO concentrations greater than 40 ppm under both dry and moist conditions. The HS Pt1 catalyst exhibited CO conversion levels of 100% under both dry and moist conditions.

  18. Photoexcited iron porphyrin as biomimetic catalysts

    International Nuclear Information System (INIS)

    Bartocci, C.; Maldotti, A.; Varani, G.; Consiglio Nazionale delle Ricerche, Ferrara

    1996-01-01

    Photoexcited iron porphyrins can be of some interest in both fine and industrial chemistry in view of the preparation of new efficient biomimetic catalysts, working with high selectivity under mild temperature and pressure

  19. Eggshell waste as catalyst: A review.

    Science.gov (United States)

    Laca, Amanda; Laca, Adriana; Díaz, Mario

    2017-07-15

    Agricultural wastes are some of the most emerging problems in food industries because of their disposal cost. However, it is also an opportunity for the bioeconomy society if new uses for these residual materials can be found. Eggshells, considered a hazardous waste by UE regulations, are discarded, amounting hundreds of thousands of tonnes worldwide. This egg processing waste is a valuable source material, which can be used in different fields such as fodder or fertilizer production. Additionally, this residue offers interesting characteristics to be used in other applications, like its employment as an environment-friendly catalyst. In the present review we provide a global view of eggshell waste uses as catalyst in different processes. According to reviewed researching works, a huge variety of added value products can be obtained by using this catalyst which emphasised the interest of further investigations in order to widen the possible uses of this cheap green catalyst. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Highly sensitive silicon microreactor for catalyst testing

    DEFF Research Database (Denmark)

    Henriksen, Toke Riishøj; Olsen, Jakob Lind; Vesborg, Peter Christian Kjærgaard

    2009-01-01

    by directing the entire gas flow through the catalyst bed to a mass spectrometer, thus ensuring that nearly all reaction products are present in the analyzed gas flow. Although the device can be employed for testing a wide range of catalysts, the primary aim of the design is to allow characterization of model...... catalysts which can only be obtained in small quantities. Such measurements are of significant fundamental interest but are challenging because of the low surface areas involved. The relationship between the reaction zone gas flow and the pressure in the reaction zone is investigated experimentally......, it is found that platinum catalysts with areas as small as 15 mu m(2) are conveniently characterized with the device. (C) 2009 American Institute of Physics. [doi:10.1063/1.3270191]...

  1. Entrepreneurship as a Catalyst for Rural Tourism Development

    Directory of Open Access Journals (Sweden)

    Md Sharif Norhafiza

    2014-01-01

    Full Text Available The tourism industry is seen as capable of being an agent of change in the landscape of economic, social and environment of a tourist destination. Tourism activity has also generated employment and entrepreneurship opportunities to the local community as well as using available resources as tourist attractions. The tourism sector has the potential to be a catalyst for the development of entrepreneurship and small business performance. Through the development of tourism, the rural community has the opportunity to offer services or sell products to the both local and foreign tourists. To fulfill this purpose, local community participation in entrepreneurship is very important in order to develope the economic potential and to determine the direction of a development in rural areas. In the context of entrepreneurship, local participation is important not only as an entrepreneur and labor in this sector as well as complementary sectors of the others, but they can serve to encourage the involvement of other residents to join together to develop this entrepreneurial. This article aims to discuss the extent of entrepreneurship as a catalyst to the development of tourism in rural areas. Through active participation among community members, rural entrepreneurship will hopefully move towards prosperity and success of rural development.

  2. Liquid phase hydrogenation of acethydrazone to N'-methyl acethydrazide over Pd/γ-Al2O3 catalyst

    Directory of Open Access Journals (Sweden)

    S. G. Pakdehi

    2010-03-01

    Full Text Available Catalytic hydrogenation of acethydrazide (AH is the main step in the production of N'-methyl acethydrazide (MAH. In this step, AH reacts with formaldehyde to produce acetylhydrazone (AOH. AOH is hydrogenated in the presence of 5% Pd/γ-Al2O3 catalyst to MAH. In this paper, the effects of hydrogen pressure, catalyst loading and initial concentration of AOH on the initial rate of hydrogenation were studied in a batch slurry reactor within a temperature range of 303-333K. The hydrogenation rate was first order with respect to hydrogen concentration at lower hydrogen pressures. However, at higher pressures, the rate became independent of both hydrogen and initial AOH concentrations. A single site Langmuir-Hinshelwood type formulation was found to describe adequately the kinetic data. A good correlation was observed between the predicted concentration vs. time profiles and those determined experimentally. The apparent activation energy was calculated from the initial rates as 40.6 kJ/mol.

  3. Oxidation Catalyst Studies on a Diesel Engine

    OpenAIRE

    Ye, Shifei

    2010-01-01

    In this thesis, the experimental test facilities consisted of a well instrumented live Ford 2.0 litre turbocharged diesel engine connected to a specially made exhaust can, which contained a diesel oxidation catalyst (DOC). Experiments were performed on DOCs, which were specially prepared by Johnson Matthey, and had thermocouples mounted in their walls to measure axial temperature profiles. These DOCs consisted of a Pt catalyst dispersed in an alumina washcoat on a cordierite monolith supports...

  4. Catalyst system of the structured type

    OpenAIRE

    Jansen, J.C.; Legein, C.H.; Calis, H.P.A.; Van Bekkum, H.; Gerritsen, A.W.; Van den Bleek, M.

    1994-01-01

    The invention relates to a catalyst system of the structured type, in which a structured support is covered with a layer of molecular sieve crystals and/or modifications thereof. These crystals have substantially the same orientation relative to the support surface. The invention further relates to a reactor in which this catalyst system is incorporated. Finally, the invention relates to a method for the selective reduction of nitrogen oxides utilizing a compound comprising a NH group, in whi...

  5. Silica supported nickel catalysts : Tracer studies.

    OpenAIRE

    Sharratt, Andrew Paul.

    1991-01-01

    A series of silica supported catalysts were prepared by impregnation of the support materials with a nickel(II) nitrate precursor under standard conditions. The catalysts and silicas were characterised using temperature programmed reduction (TPR) techniques, neutron diffraction, small angle neutron scattering, and 29Si magic angle spinning nuclear magnetic resonance (MAS-NMR). These analyses revealed one significant variable in the silicas:- the surface concentration of strained siloxane ring...

  6. Investigating Zirconia Catalysts = Handling Sensitive Materials

    OpenAIRE

    Klose, Barbara S.; Jentoft, Rolf E.; Hahn, Alexander H. P.; Ressler, Thorsten; Yang, Xiaobo; Jentoft, Friederike C.

    2003-01-01

    Investigating Zirconia Catalysts = Handling Sensitive Materials B.S. Klose, R.E. Jentoft, A. Hahn, T. Ressler, X. Yang, F.C. Jentoft Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society Faradayweg 4-6, D-14195 Berlin, Germany Introduction Sulfated zirconia (SZ) based catalysts are active for n-butane isomerization at 373 K [1]. Despite intense research, no convincing structure-activity relationship for these materials has evolved. Still in question...

  7. Single-layer transition metal sulfide catalysts

    Science.gov (United States)

    Thoma, Steven G [Albuquerque, NM

    2011-05-31

    Transition Metal Sulfides (TMS), such as molybdenum disulfide (MoS.sub.2), are the petroleum industry's "workhorse" catalysts for upgrading heavy petroleum feedstocks and removing sulfur, nitrogen and other pollutants from fuels. We have developed an improved synthesis technique to produce SLTMS catalysts, such as molybdenum disulfide, with potentially greater activity and specificity than those currently available. Applications for this technology include heavy feed upgrading, in-situ catalysis, bio-fuel conversion and coal liquefaction.

  8. HETEROPOLYACIDES AS GREEN AND REUSABLE CATALYSTS ...

    African Journals Online (AJOL)

    Preferred Customer

    and eco-friendly catalysts for both redox and/or acid–base type reactions in industrial ... The reaction mixture was stirred for 45min under refluxing conditions. ... Heteropolyacides as green and reusable catalysts for synthesis of [3,4-b][1,3,4] thiadiazines. Bull. Chem. Soc. Ethiop. 2014, 28(1). 69. NH. N. N. S. O. NH2. CH3. Ph.

  9. Catalyst for hydrogen-amine D exchange

    International Nuclear Information System (INIS)

    Holtslander, W.J.; Johnson, R.E.

    1977-01-01

    In a process for enrichment of deuterium by contacting hydrogen with an amine (such as methylamine), an alkali metal amide (such as potassium methylamide) is used as a catalyst. The present improvement is to use a mixture of two metal amides (e.g. lithium methylamide plus potassium methylamide) in order to prevent precipitation of a hydride and to reduce thermal decomposition of the catalyst. (NDH)

  10. Tetraalkylammonium Salts as Hydrogen-Bonding Catalysts

    OpenAIRE

    Shirakawa, Seiji; Liu, Shiyao; Kaneko, Shiho; Kumatabara, Yusuke; Fukuda, Airi; Omagari, Yumi; Maruoka, Keiji

    2015-01-01

    Although the hydrogen-bonding ability of the α hydrogen atoms on tetraalkylammonium salts is often discussed with respect to phase-transfer catalysts, catalysis that utilizes the hydrogen-bond-donor properties of tetraalkylammonium salts remains unknown. Herein, we demonstrate hydrogen-bonding catalysis with newly designed tetraalkylammonium salt catalysts in Mannich-type reactions. The structure and the hydrogen-bonding ability of the new ammonium salts were investigated by X-ray diffraction...

  11. In operando Detection of Three-Way Catalyst Aging by a Microwave-Based Method: Initial Studies

    Directory of Open Access Journals (Sweden)

    Gregor Beulertz

    2015-07-01

    Full Text Available Initial studies on aging detection of three way catalysts with a microwave cavity perturbation method were conducted. Two physico-chemical effects correlate with the aging state. At high temperatures, the resonance frequencies for oxidized catalysts (λ = 1.02 are not influenced by aging, but are significantly affected by aging in the reduced case (λ = 0.98. The catalyst aging state can therefore potentially be inferred from the resonance frequency differences between reduced and oxidized states or from the resonance frequency amplitudes during lambda oscillations. Secondly, adsorbed water at low temperatures strongly affects the resonance frequencies. Light-off experiment studies showed that the resonance frequency depends on the aging state at temperatures below the oxygen storage light-off. These differences were attributed to different water sorption capabilities of differently aged samples due to a surface area decrease with proceeding aging. In addition to the aging state, the water content in the feed gas and the temperature affect the amount of adsorbed water, leading to different integral electrical material properties of the catalyst and changing the resonance properties of the catalyst-filled canning. The classical aging-related properties of the catalyst (oxygen storage capacity, oxygen storage light-off, surface area, agreed very well with data obtained by the microwave-based method.

  12. Hierarchical nanostructured hollow spherical carbon with mesoporous shell as a unique cathode catalyst support in proton exchange membrane fuel cell.

    Science.gov (United States)

    Fang, Baizeng; Kim, Jung Ho; Kim, Minsik; Kim, Minwoo; Yu, Jong-Sung

    2009-03-07

    Hierarchical nanostructured spherical carbon with hollow macroporous core in combination with mesoporous shell has been explored to support Pt cathode catalyst with high metal loading in proton exchange membrane fuel cell (PEMFC). The hollow core-mesoporous shell carbon (HCMSC) has unique structural characteristics such as large specific surface area and mesoporous volume, ensuring uniform dispersion of the supported high loading (60 wt%) Pt nanoparticles with small particle size, and well-developed three-dimensionally interconnected hierarchical porosity network, facilitating fast mass transport. The HCMSC-supported Pt(60 wt%) cathode catalyst has demonstrated markedly enhanced catalytic activity toward oxygen reduction and greatly improved PEMFC polarization performance compared with carbon black Vulcan XC-72 (VC)-supported ones. Furthermore, the HCMSC-supported Pt(40 wt%) or Pt(60 wt%) outperforms the HCMSC-supported Pt(20 wt%) even at a low catalyst loading of 0.2 mg Pt cm(-2) in the cathode, which is completely different from the VC-supported Pt catalysts. The capability of supporting high loading Pt is supposed to accelerate the commercialization of PEMFC due to the anticipated significant reduction in the amount of catalyst support required, diffusion layer thickness and fabricating cost of the supported Pt catalyst electrode.

  13. Germanium nanowires grown using different catalyst metals

    Energy Technology Data Exchange (ETDEWEB)

    Gouveia, R.C., E-mail: riama@ifsp.edu.br [Departamento de Física – NanO Lab, Universidade Federal de São Carlos, Rod. Washington Luís, Km 235 – SP 310, São Carlos, CEP 13565-905 (Brazil); Área de Ciências, Instituto Federal de Educação Ciência e Tecnologia de São Paulo, Rua Américo Ambrósio, 269, Jd. Canaã, Sertãozinho, CEP 14169-263 (Brazil); Kamimura, H.; Munhoz, R.; Rodrigues, A.D. [Departamento de Física – NanO Lab, Universidade Federal de São Carlos, Rod. Washington Luís, Km 235 – SP 310, São Carlos, CEP 13565-905 (Brazil); Leite, E.R. [Departamento de Química – LIEC, Universidade Federal de São Carlos, São Carlos, CEP 13565-905 (Brazil); Chiquito, A.J. [Departamento de Física – NanO Lab, Universidade Federal de São Carlos, Rod. Washington Luís, Km 235 – SP 310, São Carlos, CEP 13565-905 (Brazil)

    2016-11-01

    Germanium nanowires have been synthesized by the well known vapor-liquid-solid growth mechanism using gold, silver, cooper, indium and nickel as catalyst metals. The influence of metal seeds on nanowires structural and electronic transport properties was also investigated. Electron microscopy images demonstrated that, despite differences in diameters, all nanowires obtained presented single crystalline structures. X-ray patterns showed that all nanowires were composed by germanium with a small amount of germanium oxide, and the catalyst metal was restricted at the nanowires' tips. Raman spectroscopy evidenced the long range order in the crystalline structure of each sample. Electrical measurements indicated that variable range hopping was the dominant mechanism in carrier transport for all devices, with similar hopping distance, regardless the material used as catalyst. Then, in spite of the differences in synthesis temperatures and nanowires diameters, the catalyst metals have not affected the composition and crystalline quality of the germanium nanowires nor the carrier transport in the germanium nanowire network devices. - Highlights: • Ge nanowires were grown by VLS method using Au, Ag, Cu, In and Ni as catalysts. • All nanowires presented high single crystalline quality and long range order. • Devices showed semiconducting behavior having VRH as dominant transport mechanism. • The metal catalyst did not influence structural properties or the transport mechanism.

  14. Low temperature catalysts for methanol production

    Science.gov (United States)

    Sapienza, Richard S.; Slegeir, William A.; O'Hare, Thomas E.; Mahajan, Devinder

    1986-01-01

    A catalyst and process useful at low temperatures (below about 160.degree. C.) and preferably in the range 80.degree.-120.degree. C. used in the production of methanol from carbon monoxide and hydrogen is disclosed. The catalyst is used in slurry form and comprises a complex reducing agent derived from the component structure NaH--RONa--M(OAc).sub.2 where M is selected from the group consisting of Ni, Pd, and Co and R is a lower alkyl group containing 1-6 carbon atoms. This catalyst is preferably used alone but is also effective in combination with a metal carbonyl of a group VI (Mo, Cr, W) metal. The preferred catalyst precursor is Nic (where M=Ni and R=tertiary amyl). Mo(CO).sub.6 is the preferred metal carbonyl if such component is used. The catalyst is subjected to a conditioning or activating step under temperature and pressure, similar to the parameters given above, to afford the active catalyst.

  15. Low temperature catalysts for methanol production

    Science.gov (United States)

    Sapienza, R.S.; Slegeir, W.A.; O'Hare, T.E.; Mahajan, D.

    1985-03-12

    A catalyst and process useful at low temperatures (below about 160/sup 0/C) and preferably in the range 80 to 120/sup 0/C used in the production of methanol from carbon monoxide and hydrogen is disclosed. The catalyst is used in slurry form and comprises a complex reducing agent derived from the component structure NaH-RONa-M(OAc)/sub 2/ where M is selected from the group consisting of Ni, Pd, and Co and R is a lower alkyl group containing 1 to 6 carbon atoms. This catalyst is preferably used alone but is also effective in combination with a metal carbonyl of a group VI (Mo, Cr, W) metal. The preferred catalyst precursor is Nic (where M = Ni and R = tertiary amyl). Mo(CO)/sub 6/ is the preferred metal carbonyl if such component is used. The catalyst is subjected to a conditioning or activating step under temperature and pressure, similar to the parameters given above, to afford the active catalyst.

  16. Polypropylene reinvented: Costs of using metallocene catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Brockmeier, N.F.

    1996-05-01

    This study develops scoping estimates of the required capital investment and manufacturing costs to make a zirconocene catalyst/cocatalyst system [(F{sub 6}-acen)Zr(CH{sub 2}CMe{sub 3})(NMe{sub 2}Ph)][B(C{sub 6}F{sub 5}){sub 4}] immobilized on a silica support. Costs for this fluorine-based system are compared with estimates for two other metallocene catalysts using methylaluminoxane (MAO)-based cocatalysts. Including wt of support and cocatalyst, each of the production facilities for making the 3 zirconocene catalyst systems is sized at 364--484 tonnes/year. Cost to make the F-based catalyst system is estimated to be $10780/kg, assuming 20% return on capital invested. Costs for the two MAO-based catalyst system fall in the range of $10950--12160/kg, assuming same return. Within the {plus_minus}50% accuracy of these estimates, these differences are not significant. Given a catalyst productivity of 250 kg resin/gram zirconocene, the cost contribution in the finished ethylene-propylene copolymer resin is 4.4 cents/kg, excluding selling, administrative, research costs.

  17. Rhodium catalysts bound to functionalized mesoporous silica

    Energy Technology Data Exchange (ETDEWEB)

    Bitterwolf, Thomas E.; Newell, J D.; Carver, Colin T.; Addleman, Raymond S.; Linehan, John C.; Fryxell, Glen E.

    2004-07-20

    Phosphine and amine functionalized mesoporous silica materials were metallated with Rh(CO)2(i-Pr2NH)Cl or Rh2(CO)4Cl2, respectively, to yield catalysts containing the Rh(PPh2R)2(CO)Cl or Rh(CO)2(NH2R)Cl, where R is a propyl chain bonded to the silica surface, reactive centers. In order to ascertain the effect of pore size on rates of hydroformylation catalysis both 35 and 45 ? pore size materials were used. Using the hydroformylation of octene as a reference reaction, the phosphine based, 45 ? catalysts were 1.5-1.3 times faster than the amine based, 45 ? materials were 2.6-2.1 times faster than the 35 ? catalysts, and the 45 ? materials. The orientation of the catalyst relative to the functionalized surface, and the steric environment around the catalyst active site appear to be significant in determining rate of reaction. The ability of the surface bound phosphine catalysts to affect hydroformylation was strongly influenced by the steric constraints of the substrate. Terminal alkenes were readily hydroformylated and norbornene was slowly hydroformylated, but pinene, trans-cyclododecene, cyclohexene and cholesterol were nonreactive to the catalytic center.

  18. Sulfur deactivation of fatty ester hydrogenolysis catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Brands, D.S.; U-A-Sai, G.; Poels, E.K.; Bliek, A. [Univ. of Amsterdam (Netherlands). Dept. of Chemical Engineering

    1999-08-15

    Trace organosulfur compounds present as natural impurities in oleochemical feedstocks may lead to activation of copper-containing catalysts applied for hydrogenolysis of esters toward fatty alcohols. In this paper, the sulfur deactivation of Cu/SiO{sub 2} and Cu/ZnO/SiO{sub 2} catalysts was studied in the liquid-phase hydrogenolysis of methyl palmitate. The rate of deactivation is fast and increases as a function of the sulfur-containing compound present: octadecanethiol {approx} dihexadecyl disulfide < benzyl isothiocyanate < methyl p-toluene sulfonate < dihexadecyl sulfide < dibenzothiophene. The rapid deactivation is caused by the fact that sulfur is quantitatively removed from the reaction mixture and because mainly surface sulfides are formed under hydrogenolysis conditions. The life time of a zinc-promoted catalyst is up to two times higher than that of the Cu/SiO{sub 2} catalyst, most likely due to zinc surface sulfide formation. The maximum sulfur coverage obtained after full catalyst deactivation with dibenzothiophene and dihexadecyl sulfide--the sulfur compounds that cause the fastest deactivation--may be as low as 0.07. This is due to the fact that decomposition of these compounds as well as the hydrogenolysis reaction itself proceeds on ensembles of copper atoms. Catalyst regeneration studies reveal that activity cannot be regained by reduction or combined oxidation/reduction treatments. XRD, TPR, and TPO results confirm that no distinct bulk copper or zinc sulfide or sulfate phases are present.

  19. Hollow Nano- and Microstructures as Catalysts.

    Science.gov (United States)

    Prieto, Gonzalo; Tüysüz, Harun; Duyckaerts, Nicolas; Knossalla, Johannes; Wang, Guang-Hui; Schüth, Ferdi

    2016-11-23

    Catalysis is at the core of almost every established and emerging chemical process and also plays a central role in the quest for novel technologies for the sustainable production and conversion of energy. Particularly since the early 2000s, a great surge of interest exists in the design and application of micro- and nanometer-sized materials with hollow interiors as solid catalysts. This review provides an updated and critical survey of the ever-expanding material architectures and applications of hollow structures in all branches of catalysis, including bio-, electro-, and photocatalysis. First, the main synthesis strategies toward hollow materials are succinctly summarized, with emphasis on the (regioselective) incorporation of various types of catalytic functionalities within their different subunits. The principles underlying the scientific and technological interest in hollow materials as solid catalysts, or catalyst carriers, are then comprehensively reviewed. Aspects covered include the stabilization of catalysts by encapsulation, the introduction of molecular sieving or stimuli-responsive "auxiliary" functionalities, as well as the single-particle, spatial compartmentalization of various catalytic functions to create multifunctional (bio)catalysts. Examples are also given on the applications which hollow structures find in the emerging fields of electro- and photocatalysis, particularly in the context of the sustainable production of chemical energy carriers. Finally, a critical perspective is provided on the plausible evolution lines for this thriving scientific field, as well as the main practical challenges relevant to the reproducible and scalable synthesis and utilization of hollow micro- and nanostructures as solid catalysts.

  20. Extension of TRIGA reactor capabilities

    International Nuclear Information System (INIS)

    Gietzen, A.J.

    1980-01-01

    The first TRIGA reactor went into operation at 10 kW about 22 years ago. Since that time 55 TRIGAs have been put into operation including steady-state powers up to 14,000 kW and pulsing reactors that pulse to 20,000,000 kW. Five more are under construction and a proposal will soon be submitted for a reactor of 25,000 kW. Along with these increases in power levels (and the corresponding fluxes) the experimental facilities have also been expanded. In addition to the installation of new TRIGA reactors with enhanced capabilities many of the older reactors have been modified and upgraded. Also, a number of reactors originally fueled with plate fuel were converted to TRIGA fuel to take advantage of the improved technical and safety characteristics, including the ability for pulsed operation. In order to accommodate increased power and performance the fuel has undergone considerable evolution. Most of the changes have been in the geometry, enrichment and cladding material. However, more recently further development on the UZrH alloy has been carried out to extend the uranium content up to 45% by weight. This increased U content is necessary to allow the use of less than 20% enrichment in the higher powered reactors while maintaining longer core lifetime. The instrumentation and control system has undergone remarkable improvement as the electronics technology has evolved so rapidly in the last two decades. The information display and the circuitry logic has also undergone improvements for enhanced ease of operation and safety. (author)

  1. Manganese and Iron Catalysts in Alkyd Paints and Coatings

    Directory of Open Access Journals (Sweden)

    Ronald Hage

    2016-04-01

    Full Text Available Many paint, ink and coating formulations contain alkyd-based resins which cure via autoxidation mechanisms. Whilst cobalt-soaps have been used for many decades, there is a continuing and accelerating desire by paint companies to develop alternatives for the cobalt soaps, due to likely classification as carcinogens under the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals legislation. Alternative driers, for example manganese and iron soaps, have been applied for this purpose. However, relatively poor curing capabilities make it necessary to increase the level of metal salts to such a level that often coloring of the paint formulation occurs. More recent developments include the application of manganese and iron complexes with a variety of organic ligands. This review will discuss the chemistry of alkyd resin curing, the applications and reactions of cobalt-soaps as curing agents, and, subsequently, the paint drying aspects and mechanisms of (model alkyd curing using manganese and iron catalysts.

  2. Visible-light-driven methane formation from CO2 with a molecular iron catalyst.

    Science.gov (United States)

    Rao, Heng; Schmidt, Luciana C; Bonin, Julien; Robert, Marc

    2017-08-03

    Converting CO 2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO 2 emissions. One strategy aims for electrochemical conversions powered by electricity from renewable sources, but photochemical approaches driven by sunlight are also conceivable. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO 2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare. Here we show that an iron tetraphenylporphyrin complex functionalized with trimethylammonio groups, which is the most efficient and selective molecular electro- catalyst for converting CO 2 to CO known, can also catalyse the eight-electron reduction of CO 2 to methane upon visible light irradiation at ambient temperature and pressure. We find that the catalytic system, operated in an acetonitrile solution containing a photosensitizer and sacrificial electron donor, operates stably over several days. CO is the main product of the direct CO 2 photoreduction reaction, but a two-pot procedure that first reduces CO 2 and then reduces CO generates methane with a selectivity of up to 82 per cent and a quantum yield (light-to-product efficiency) of 0.18 per cent. However, we anticipate that the operating principles of our system may aid the development of other molecular catalysts for the production of solar fuels from CO 2 under mild conditions.

  3. Visible-light-driven methane formation from CO2 with a molecular iron catalyst

    Science.gov (United States)

    Rao, Heng; Schmidt, Luciana C.; Bonin, Julien; Robert, Marc

    2017-08-01

    Converting CO2 into fuel or chemical feedstock compounds could in principle reduce fossil fuel consumption and climate-changing CO2 emissions. One strategy aims for electrochemical conversions powered by electricity from renewable sources, but photochemical approaches driven by sunlight are also conceivable. A considerable challenge in both approaches is the development of efficient and selective catalysts, ideally based on cheap and Earth-abundant elements rather than expensive precious metals. Of the molecular photo- and electrocatalysts reported, only a few catalysts are stable and selective for CO2 reduction; moreover, these catalysts produce primarily CO or HCOOH, and catalysts capable of generating even low to moderate yields of highly reduced hydrocarbons remain rare. Here we show that an iron tetraphenylporphyrin complex functionalized with trimethylammonio groups, which is the most efficient and selective molecular electro- catalyst for converting CO2 to CO known, can also catalyse the eight-electron reduction of CO2 to methane upon visible light irradiation at ambient temperature and pressure. We find that the catalytic system, operated in an acetonitrile solution containing a photosensitizer and sacrificial electron donor, operates stably over several days. CO is the main product of the direct CO2 photoreduction reaction, but a two-pot procedure that first reduces CO2 and then reduces CO generates methane with a selectivity of up to 82 per cent and a quantum yield (light-to-product efficiency) of 0.18 per cent. However, we anticipate that the operating principles of our system may aid the development of other molecular catalysts for the production of solar fuels from CO2 under mild conditions.

  4. Applications of low temperature CO-oxidation catalysts to breathable gases

    Science.gov (United States)

    Noordally, Ehsan; Richmond, John R.

    1990-01-01

    Modifications of tin oxide/precious metal catalysts described for use in CO2 lasers have also been developed for use in other applications; namely, as low temperature CO oxidation components in fire escape hoods/masks for mines, aircrafts, hotels, and offices and in sealed environments, such as hyperbaric chambers and submarines. Tin oxide/precious metal catalysts have been prepared on a variety of high surface area cloth substrates for application in fire escape hoods. These show high and stable CO oxidation capability (10 to the 4th power ppm CO reduced to 10 to the 1st power ppm CO) at GHSV of 37,000 h(-1) with water saturated inlet gas at body heat (37 C) and below. Water vapor plays an important role in the surface state/performance of tin oxide catalyst. Water-resistant formulations have been produced by the introduction of transition metal promoters. Tin oxide/precious metal catalysts have also been developed for CO oxidation in the North Sea diving environment. These are currently in use in a variety of hyperbaric chambers and diving vehicles. Ambient temperature operation and resistance to atmospheric water vapor have been demonstrated, and as a result, they offer a viable alternative to hopcalite or heated catalyst systems. A new range of non-tin oxide based low temperature CO oxidation catalysts is described. They are based on reducible metal oxides promoted with previous metals. Preliminary data on selected materials in the form of both cloth artifacts and shaped pellets are presented. They are expected to be applicable both to the breathable gas application area and to CO2 lasers.

  5. Catalytic reduction of NOx in gasoline engine exhaust over copper- and nickel-exchanged X-zeolite catalysts

    International Nuclear Information System (INIS)

    Bhattacharyya, S.; Das, R.K.

    2001-01-01

    Catalytic removal of NO x in engine exhaust gases can be accomplished by non-selective reduction, selective reduction and decomposition. Noble metals are extensively used for non-selective reduction of NO x and up to 90% of engine NO x emissions can be reduced in a stoichiometric exhaust. This requirement of having the stoichiometric fuel-air ratio acts against efficiency improvement of engines. Selective NO x reduction in the presence of different reductants such as, NH 3 , urea or hydrocarbons, requires close control of the amount of reductant being injected which otherwise may be emitted as a pollutant. Catalytic decomposition is the best option for NO x removal. Nevertheless, catalysts which are durable, economic and active for NO x reduction at normal engine exhaust temperature ranges are still being investigated. Three catalysts based on X-zeolite have been developed by exchanging the Na+ ion with copper, nickel and copper-nickel metal ions and applied to the exhaust of a stationary gasoline engine to explore their potential for catalytic reduction of NO x under a wide range of engine and exhaust conditions. Some encouraging results have been obtained. The catalyst Cu-X exhibits much better NO x reduction performance at any temperature in comparison to Cu-Ni-X and Ni-X; while Cu-Ni-X catalyst exhibits slightly better performance than Ni-X catalyst. Maximum NO x efficiency achieved with Cu-X catalyst is 59.2% at a space velocity (sv) of 31 000 h -1 ; while for Cu-Ni-X and Ni-X catalysts the equivalent numbers are 60.4% and 56% respectively at a sv of 22 000 h -1 . Unlike noble metals, the doped X-zeolite catalysts exhibit significant NO x reduction capability for a wide range of air/fuel ratio and with a slower rate of decline as well with increase in air/fuel ratio. (author)

  6. Sandia Laboratories technical capabilities: systems analysis

    International Nuclear Information System (INIS)

    Lundergan, C.D.

    1975-06-01

    The systems analysis capabilities at Sandia Laboratories are summarized. Selected applications of these capabilities are presented to illustrate the extent to which they can be applied in research and development programs. (U.S.)

  7. Towards a national cybersecurity capability development model

    CSIR Research Space (South Africa)

    Jacobs, Pierre C

    2017-06-01

    Full Text Available - the incident management cybersecurity capability - is selected to illustrate the application of the national cybersecurity capability development model. This model was developed as part of previous research, and is called the Embryonic Cyberdefence Monitoring...

  8. Global dynamics, capabilities and the crisis

    Czech Academy of Sciences Publication Activity Database

    Fagerberg, J.; Srholec, Martin

    2016-01-01

    Roč. 26, č. 4 (2016), s. 765-784 ISSN 0936-9937 Institutional support: PRVOUK-P23 Keywords : technological capabilities * social capabilities * competitiveness Subject RIV: AH - Economics Impact factor: 0.862, year: 2016

  9. Eros-based Confined Capability Client

    National Research Council Canada - National Science Library

    Shapiro, Jonathan S

    2006-01-01

    Objective of EROS-Based Confined Capability Client Project is to demonstrate that systems constructed using capability-based protection can be organized in a way that makes it defensible from hostile internet content...

  10. DDP-516 Computer Graphics System Capabilities

    Science.gov (United States)

    1972-06-01

    This report describes the capabilities of the DDP-516 Computer Graphics System. One objective of this report is to acquaint DOT management and project planners with the system's current capabilities, applications hardware and software. The Appendix i...

  11. Studies of Heterogenous Palladium and Related Catalysts for Aerobic Oxidation of Primary Alcohols

    Science.gov (United States)

    Ahmed, Maaz S.

    Development of aerobic oxidation methods is of critical importance for the advancement of green chemistry, where the only byproduct produced is water. Recent work by our lab has produced an efficient Pd based heterogenous catalyst capable of preforming the aerobic oxidation of a wide spectrum of alcohols to either carboxylic acid or methyl ester. The well-defined catalyst PdBi 0.35Te0.23/C (PBT/C) catalyst has been shown to can perform the aerobic oxidation of alcohols to carboxylic acids in basic conditions. Additionally, we explored this catalyst for a wide range of alcohols and probed the nature of the selectivity of PBT/C for methyl esterification over other side products. Finally, means by which the catalyst operates with respect to oxidation states of the three components, Pd, Bi, and Te, was probed. Carboxylic acids are an important functional group due to their prevalence in various pharmaceutically active agents, agrochemicals, and commodity scale chemicals. The well-defined catalyst PBT/C catalyst was discovered to be effective for the oxidation of a wide spectrum of alcohols to carboxylic acid. The demonstrated substrate scope and functional group tolerance are the widest reported for an aerobic heterogeneous catalyst. Additionally, the catalyst has been implemented in a packed bed reactor with quantitative yield of benzoic acid maintained throughout a two-day run. Biomass derived 5-(hydroxymethyl)furfural (HMF) is also oxidized to 2,5-furandicarboxylic acid (FDCA) in high yield. Exploration of PBT/C for the oxidative methyl esterification was found to exhibit exquisite selectivity for the initial oxidation of primary alcohol instead of methanol, which is the bulk solvent. We explored this selectivity and conclude that it results from various substrate-surface interactions, which are not attainable by methanol. The primary alcohol can outcompete the methanol for binding on the catalyst surface through various interactions between the side chain of the

  12. DESIGNING AND MEASURING CAPABILITY. A NEW PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Ovidiu COCENESCU

    2013-01-01

    Full Text Available The concept of capability has long been a topic for debate among planners. The main benefit brought by it is that of ensuring the connection between objectives and necessary financial resources. Thus, capability is a median element within the process of integrated planning. In this context, there are sceptics who consider that capability cannot be measured. However, this article aims at presenting a pattern and a formula for measuring and interpreting the level of capability.

  13. Single Cobalt Atoms with Precise N-Coordination as Superior Oxygen Reduction Reaction Catalysts.

    Science.gov (United States)

    Yin, Peiqun; Yao, Tao; Wu, Yuen; Zheng, Lirong; Lin, Yue; Liu, Wei; Ju, Huanxin; Zhu, Junfa; Hong, Xun; Deng, Zhaoxiang; Zhou, Gang; Wei, Shiqiang; Li, Yadong

    2016-08-26

    A new strategy for achieving stable Co single atoms (SAs) on nitrogen-doped porous carbon with high metal loading over 4 wt % is reported. The strategy is based on a pyrolysis process of predesigned bimetallic Zn/Co metal-organic frameworks, during which Co can be reduced by carbonization of the organic linker and Zn is selectively evaporated away at high temperatures above 800 °C. The spherical aberration correction electron microscopy and extended X-ray absorption fine structure measurements both confirm the atomic dispersion of Co atoms stabilized by as-generated N-doped porous carbon. Surprisingly, the obtained Co-Nx single sites exhibit superior ORR performance with a half-wave potential (0.881 V) that is more positive than commercial Pt/C (0.811 V) and most reported non-precious metal catalysts. Durability tests revealed that the Co single atoms exhibit outstanding chemical stability during electrocatalysis and thermal stability that resists sintering at 900 °C. Our findings open up a new routine for general and practical synthesis of a variety of materials bearing single atoms, which could facilitate new discoveries at the atomic scale in condensed materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Catalytic Transformation of Ethylbenzene over Y-Zeolite-based Catalysts

    KAUST Repository

    Al-Khattaf, Sulaiman

    2008-11-19

    Catalytic transformation of ethylbenzene (EB) has been investigated over ultrastable Y (USY)-zeolite-based catalysts in a novel riser simulator at different operating conditions. The effect of reaction conditions on EB conversion is reported. The USY catalyst (FCC-Y) was modified by steaming to form a significantly lower acidity catalyst (FCC-SY). The current study shows that the FCC-SY catalyst favors EB disproportionation more than cracking. A comparison has been made between the results of EB conversion over the lowly acidic catalyst (FCC-SY) and the highly acidic catalyst (FCC-Y) under identical conditions. It was observed that increase in catalyst acidity favored cracking of EB at the expense of disproportionation. Kinetic parameters for EB disappearance during disproportionation reaction over the FCC-SY catalyst were calculated using the catalyst activity decay function based on time on stream (TOS). © 2008 American Chemical Society.

  15. Interaction between Nafion ionomer and noble metal catalyst for PEMFCs

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma

    The implement of polymer impregnation in electrode structure (catalyst layer) decreasing the noble metal catalyst loading by a factor of ten , , is one of the essential mile stones in the evolution of Proton Exchange Membrane Fuel Cells’ development among the application of catalyst support...... and electrode deposition etc. In fuel cell reactions, both electrons and protons are involved. Impregnation of Nafion ionomer in catalyst layer effectively increases the proton-electron contact, enlarge the reaction zone, extend the reaction from the surface to the entire electrode. Therefore, the entire...... catalyst layer conducts both electrons and protons so that catalyst utilization in the layer is improved dramatically. The catalyst layer will in turn generate and sustain a higher current density. One of the generally adapted methods to impregnate Nafion into the catalyst layer is to mix the catalysts...

  16. Organisational Capability--What Does It Mean?

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2006

    2006-01-01

    Organisational capability is rapidly becoming recognized as the key to organizational success. However, the lack of research on it has been well documented in the literature, and organizational capability remains an elusive concept. Yet an understanding of organizational capability can offer insights into how RTOs might work most effectively,…

  17. The capabilities conception of the individual

    NARCIS (Netherlands)

    Davis, J.B.

    2009-01-01

    This paper advances a capabilities conception of the individual, and considers some of the problems involved in developing such a conception. It also makes claims about the nature of the capability space as a whole, frames personal development in terms of the idea of moving though the capability

  18. Selecting Capabilities for Quality of Life Measurement

    Science.gov (United States)

    Robeyns, Ingrid

    2005-01-01

    The capability approach advocates that interpersonal comparisons be made in the space of functionings and capabilities. However, Amartya Sen has not specified which capabilities should be selected as the relevant ones. This has provoked two types of criticism. The stronger critique is Martha Nussbaum's claim that Sen should endorse one specific…

  19. Multiscale modeling for materials design: Molecular square catalysts

    Science.gov (United States)

    Majumder, Debarshi

    In a wide variety of materials, including a number of heterogeneous catalysts, the properties manifested at the process scale are a consequence of phenomena that occur at different time and length scales. Recent experimental developments allow materials to be designed precisely at the nanometer scale. However, the optimum design of such materials requires capabilities to predict the properties at the process scale based on the phenomena occurring at the relevant scales. The thesis research reported here addresses this need to develop multiscale modeling strategies for the design of new materials. As a model system, a new system of materials called molecular squares was studied in this research. Both serial and parallel multiscale strategies and their components were developed as parts of this work. As a serial component, a parameter estimation tool was developed that uses a hierarchical protocol and consists of two different search elements: a global search method implemented using a genetic algorithm that is capable of exploring large parametric space, and a local search method using gradient search techniques that accurately finds the optimum in a localized space. As an essential component of parallel multiscale modeling, different standard as well as specialized computational fluid dynamics (CFD) techniques were explored and developed in order to identify a technique that is best suited to solve a membrane reactor model employing layered films of molecular squares as the heterogeneous catalyst. The coupled set of non-linear partial differential equations (PDEs) representing the continuum model was solved numerically using three different classes of methods: a split-step method using finite difference (FD); domain decomposition in two different forms, one involving three overlapping subdomains and the other involving a gap-tooth scheme; and the multiple-timestep method that was developed in this research. The parallel multiscale approach coupled continuum

  20. Optimal catalyst curves: Connecting density functional theory calculations with industrial reactor design and catalyst selection

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Dahl, Søren; Boisen, A.

    2002-01-01

    For ammonia synthesis catalysts a volcano-type relationship has been found experimentally. We demonstrate that by combining density functional theory calculations with a microkinetic model the position of the maximum of the volcano curve is sensitive to the reaction conditions. The catalytic...... ammonia synthesis activity, to a first approximation, is a function only of the binding energy of nitrogen to the catalyst. Therefore, it is possible to evaluate which nitrogen binding energy is optimal under given reaction conditions. This leads to the concept of optimal catalyst curves, which illustrate...... the nitrogen binding energies of the optimal catalysts at different temperatures, pressures, and synthesis gas compositions. Using this concept together with the ability to prepare catalysts with desired binding energies it is possible to optimize the ammonia process. In this way a link between first...