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Sample records for residues pt 4a

  1. Hg and Pt-metals in meteorite carbon-rich residues - Suggestions for possible host phase for Hg

    Jovanovic, S.; Reed, G. W., Jr.

    1980-01-01

    Carbon-rich and oxide residual phases have been isolated from Allende and Murchison by acid demineralization for the determination of their Hg, Pt-metal, Cr, Sc, Co, and Fe contents. Experimental procedures used eliminated the possibility of exogenous and endogenous contaminant trace elements from coprecipitating with the residues. Large enrichments of Hg and Pt-metals were found in Allende but not in Murchison residues. Hg-release profiles from stepwise heating experiments suggest a sulfide as the host for Hg. Diffusion calculations for Hg based on these experiments indicate an activation energy of 7-8 kcal/mol, the same as that for Hg in troilite from an iron meteorite. This is further support for a sulfide host phase for Hg. Equilibration of Hg with this phase at approximately 900 K is indicated. Reasons for the presence of Pt-metals in noncosmic relative abundances are explored.

  2. Evaporation residue excitation function measurement for 19F + 194,198Pt reactions

    Singh, Varinderjit; Behera, B.R.; Kaur, Maninder

    2012-01-01

    Nuclear dissipation is one of the active fields in the present day nuclear physics research. Experimental signatures for dissipation are observed through large excess in pre-fission neutrons, γ-ray multiplicities from the compound nucleus, giant dipole resonance (GDR) γ-rays, light charged particles and evaporation residues in comparison to standard statistical model, for the heavy-ion induced fusion-fission or fusion-evaporation reactions (ERs). From the analysis of a large set of experimental data, it is well established that there exists a large dissipation at nuclear temperature above 1 MeV. But most of these probes are not sensitive to the dissipation within saddle. The ER cross-section is a probe which is sensitive to dissipation within the saddle point. Hence, the study of ER cross-section can be helpful in estimating the dissipation effects inside the saddle point. Also the other motivation for these measurements is to see the effect of shell closure on dissipation. With this motivation the evaporation cross-sections for 19 F + 194,198 Pt are measured at beam energy of 101 to 137.3 MeV. Of the above systems 19 F + 194 Pt populates 213 Fr (N = 126) shell closed compound nucleus (CN) whereas, other system populate 217 Fr (N = 130) non-shell closed CN

  3. Galvanic replacement mediated synthesis of hollow Pt nanocatalysts: Significance of residual Ag for the H{sub 2} evolution reaction

    Bansal, Vipul; O' Mullane, Anthony P.; Bhargava, Suresh K. [School of Applied Sciences, RMIT University, GPO Box 2476V, Melbourne VIC 3001 (Australia)

    2009-08-15

    With the increasing popularity of the galvanic replacement approach towards the development of bimetallic nanocatalysts, special emphasis has been focused on minimizing the use of expensive metal (e.g. Pt), in the finally formed nanomaterials (e.g. Ag/Pt system as a possible catalyst for fuel cells). However, the complete removal of the less active sacrificial template is generally not achieved during galvanic replacement, and its residual presence may significantly impact on the electrocatalytic properties of the final material. Here, we investigate the hydrogen evolution reaction (HER) activity of Ag nanocubes replaced with different amounts of Pt, and demonstrate how the bimetallic composition significantly affects the activity of the alloyed nanomaterial. (author)

  4. Atomically flat surface of (0 0 1) textured FePt thin films by residual stress control

    Liu, S.H. [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China); Hsiao, S.N., E-mail: pmami.hsiao@gmail.com [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China); Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chou, C.L.; Chen, S.K. [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China); Lee, H.Y. [National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Department of Applied Science, National Hsinchu University of Education, Hsinchu 300, Taiwan (China)

    2015-11-01

    Highlights: • We demonstrate crystallographic structure, (0 0 1) texture, surface roughness, and residual stress in the single-layered FePt thin films annealed at various heating rates (10–110 K/s). • Texture coefficient of (0 0 1)-plane of the samples increases with increasing heating rate from 10 to 40 K/s, which is correlated with perpendicular magnetic anisotropy and in-plane tensile stress. • Dewetting phenomenon due to stress relaxation leads to the broadening of [0 0 1] easy axis and degradation of perpendicular magnetic anisotropy. • A strong dependence of surface roughness on in-plane residual stress was revealed. • When the samples are RTA at 40 K/s, the enhanced perpendicular magnetic anisotropy and atomically surface roughness are achieved. - Abstract: Single-layered Fe{sub 52}Pt{sub 48} films with thickness of 10 nm were sputter-deposited on glass substrates. Rapid thermal annealing with different heating rates (10–110 K/s) was applied to transform as-deposited fcc phase into L1{sub 0} phase and meanwhile to align [0 0 1]-axis of L1{sub 0} crystal along plane normal direction. Based on X-ray diffractometry using synchrotron radiation source, the texture coefficient of (0 0 1)-plane increases with increasing heating rate from 10 to 40 K/s, which is correlated with perpendicular magnetic anisotropy and in-plane tensile stress analyzed by asymmetric sin{sup 2} ψ method. Furthermore, it was revealed by atomic force microscopy that the dewetting process occurred as heating rate was raised up to 80 K/s and higher. The change in the microstructure due to stress relaxation leads to the degradation of (0 0 1) orientation and magnetic properties. Surface roughness is closely related to the in-plane tensile stress. Enhanced perpendicular magnetic anisotropy and atomically flat surface were achieved for the samples annealed at 40 K/s, which may be suitable for further practical applications. This work also suggests a feasible way for surface

  5. On the residual stress and picostructure of titanium nitride films. Pt. 1

    Perry, A.J.; Valvoda, V.; Rafaja, D.; Williamson, D.L.; Sartwell, B.D.

    1992-01-01

    Titanium nitride films, dual energy ion implanted with argon or krypton, have been studied with a Seemann-Bohlin fine focus goniometer at grazing angles in the range 2-10. The implantation of 1% of either gas has little effect on the lattice parameters or the residual stress. It is thought that the gas atoms are on substitutional lattice sites and are associated with vacancies created during the implantation process. At 4% of implanted gas, it precipitates out in the form of bubbles; in the case of argon these are crystalline and their lattice parameter is close to that for solid argon as recorded in the literature. The lattice parameters and the residual stresses are affected slightly by the implantation: argon reduces the former and makes the latter more tensile, whereas the krypton has the opposite effects. It is thought that the difference in behavior is due to a difference in size of the bubbles or to the greater compressibility of argon

  6. Measurement of Young’s modulus and residual stress of atomic layer deposited Al2O3 and Pt thin films

    Purkl, Fabian; Daus, Alwin; English, Timothy S.; Provine, J.; Feyh, Ando; Urban, Gerald; Kenny, Thomas W.

    2017-08-01

    The accurate measurement of mechanical properties of thin films is required for the design of reliable nano/micro-electromechanical devices but is increasingly challenging for thicknesses approaching a few nanometers. We apply a combination of resonant and static mechanical test structures to measure elastic constants and residual stresses of 8-27 nm thick Al2O3 and Pt layers which have been fabricated through atomic layer deposition. Young’s modulus of poly-crystalline Pt films was found to be reduced by less than 15% compared to the bulk value, whereas for amorphous Al2O3 it was reduced to about half of its bulk value. We observed no discernible dependence of the elastic constant on thickness or deposition method for Pt, but the use of plasma-enhanced atomic layer deposition was found to increase Young’s modulus of Al2O3 by 10% compared to a thermal atomic layer deposition. As deposited, the Al2O3 layers had an average tensile residual stress of 131 MPa. The stress was found to be higher for thinner layers and layers deposited without the help of a remote plasma. No residual stress values could be extracted for Pt due to insufficient adhesion of the film without an underlying layer to promote nucleation.

  7. Synthesis of Pt/C Fuel Cell Electrocatalysts: Residual Content of Chloride and Activity in Oxygen Reduction.

    Kaluža, Luděk; Larsen, M.J.; Morales, I.J.; Cavaliere, S.; Jones, D.J.; Roziere, J.; Kallistová, Anna; Dytrych, Pavel; Gulková, Daniela; Odgaard, M.

    2016-01-01

    Roč. 7, č. 4 (2016), s. 269-275 ISSN 1868-2529 R&D Projects: GA MŠk(CZ) 7HX13003 EU Projects: European Commission(XE) 303466 - IMMEDIATE Institutional support: RVO:67985858 ; RVO:67985831 Keywords : catalysts * membrane * Pt(111) Subject RIV: CF - Physical ; Theoretical Chemistry; CA - Inorganic Chemistry (GLU-S) Impact factor: 2.398, year: 2016

  8. Recent results of measurements of evaporation residue excitation functions for 19F+194,196,198Pt and 16,18O+198Pt systems with HYRA spectrometer at IUAC

    Behera B.R.

    2015-01-01

    Full Text Available In this talk results of the evaporation residue (ER cross sections for the 19F+194,196,198Pt (forming compound nuclei 213,215,217Fr and 16,18O+198Pt (forming compound nuclei 214,216Rn systems measured at Hybrid Recoil mass Analyzer (HYRA spectrometer installed at the Pelletron+LINAC accelerator facility of the Inter University Accelerator Center (IUAC, New Delhi are reported. The survival probabilities of 215Fr and 217Fr with neutron numbers N = 126 are found to be lower than the survival probabilities of 215Fr and 217Fr with neutron numbers N = 128 and 130 respectively. Statistical model analysis of the ER cross sections show that an excitation energy dependent scaling factor of the finite-range rotating liquid drop model fission barrier is necessary to fit the experimental data. For the case of 214,216Rn, the experimental ER cross sections are compared with the predictions from the statistical model calculations of compound nuclear decay where Kramer’s fission width is used. The strength of nuclear dissipation is treated as a free parameter in the calculations to fit the experimental data.

  9. Recent results of measurements of evaporation residue excitation functions for 19F+194,196,198Pt and 16,18O+198Pt systems with HYRA spectrometer at IUAC

    Behera, B. R.

    2015-01-01

    In this talk results of the evaporation residue (ER) cross sections for the 19F+194,196,198Pt (forming compound nuclei 213,215,217Fr) and 16,18O+198Pt (forming compound nuclei 214,216Rn) systems measured at Hybrid Recoil mass Analyzer (HYRA) spectrometer installed at the Pelletron+LINAC accelerator facility of the Inter University Accelerator Center (IUAC), New Delhi are reported. The survival probabilities of 215Fr and 217Fr with neutron numbers N = 126 are found to be lower than the survival probabilities of 215Fr and 217Fr with neutron numbers N = 128 and 130 respectively. Statistical model analysis of the ER cross sections show that an excitation energy dependent scaling factor of the finite-range rotating liquid drop model fission barrier is necessary to fit the experimental data. For the case of 214,216Rn, the experimental ER cross sections are compared with the predictions from the statistical model calculations of compound nuclear decay where Kramer's fission width is used. The strength of nuclear dissipation is treated as a free parameter in the calculations to fit the experimental data.

  10. Residual stress in coated low-Z films of TiC and TiN. Pt. 2

    Yoshizawa, I.; Kabeya, Z.; Kamada, K.

    1984-01-01

    The correlations of the residual stresses with microstructures of TiC and TiN films deposited onto various substrates were examined by means of observations of SEM micrographs, X-ray back-reflected Debye rangs and diffraction line profile of X-ray spectrometer chart. It was found that specimens with lower residual stress generally show sharp line profile and good separation between Ksub(α1) and Ksub(α2) diffraction peaks in both TiN and TiC films, indicating better crystalline perfection. PVD coated TiC films on Mo and Inconel substrates show poor separation of Ksub(α1) and Ksub(α2) peaks, namely due to higher residual stresses in comparison with those of CVD coated TiN and TiC films on Mo or Inconel substrate. In CVD TiC/Pocographite system, with film thickness ranging from 10 to 100 μm, the grain size increase with increasing the thickness, except 100 μm thick specimen which has the smallest grain size in this group. However, the sharpness of diffraction profile is best in 20 μm thick film, and worst in 100 μm thick film. This is in good correlation with the amount of residual stress. (orig.)

  11. Analysis and radiological assessment of residues containing NORM materials resulting from earlier activities including modelling of typical industrial residues. Pt. 1. Historical investigation of the radiological relevance of NORM residues and concepts for site identification

    Reichelt, Andreas; Niedermayer, Matthias; Sitte, Beate; Hamel, Peter Michael

    2007-01-01

    Natural radionuclides are part of the human environment and of the raw materials used. Technical processes may cause their accumulation in residues, and the result will be so-called NORM materials (Naturally occurring radioactive material). The amended Radiation Protection Ordinance (StrlSchV 2001) specifies how the public should be protected, but there are also residues dating back before the issuing of the StrlSchV 2001, the so-called NORM residues. The project intended to assess the risks resulting from these residues. It comprises four parts. Part 1 was for clarification of the radiological relevance of NORM residues and for the development of concepts to detect them. The criterion for their radiological relevance was their activity per mass unit and the material volume accumulated through the centuries. The former was calculated from a wide bibliographic search in the relevant literature on radiation protection, while the mass volume was obtained by a detailed historical search of the consumption of materials that may leave NORM residues. These are, in particular, residues from coal and ore mining and processing. To identify concrete sites, relevant data sources were identified, and a concept for identification of concrete NORM residues was developed on this basis. (orig.) [de

  12. Evolution of microstructure and residual stress on L1{sub 0} ordering in FePt thin films with different initial stress states

    Hsiao, S.N., E-mail: pmami.hsiao@gmail.com [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China); Yuan, F.T. [iSentek Ltd., Advanced Sensor Laboratory, New Taipei City 221, Taiwan (China); Chen, S.K. [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China); Sun, A.C. [Department of Chemical Engineering and Materials Science, Yuan Ze University, Jungli 320, Taiwan (China); Su, S.H.; Chiu, K.F. [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China)

    2016-01-15

    We have characterized the dependence of microstructure, and internal strain/stress on L1{sub 0} ordering in 40 nm thick FePt films with different initial stresses. The microstructural and crystallographic results indicate that defect annihilation and grain growth induced an increase in tensile stress of ~1 GPa before extensive L1{sub 0} ordering. The induced tensile stress can efficiently facilitate the nucleation of L1{sub 0} phase owing to that the volume expansion of L1{sub 0} ordering and atomic rearrangement neutralizes the tensile stress. If the as-deposited FePt film has a highly compressive state, the induced tensile stress will be canceled out and ordering is retarded, which results in a higher ordering temperature. - Highlights: • Microstructure-stress connection in FePt films was studied. • Initial stress alters microstructure and stress evolution during annealing. • Densification induces tensile stress of ~1 GPa before extensive L1{sub 0} ordering. • Induced tensile stress can efficiently facilitate the nucleation of L1{sub 0} phase. • Compressively initial stress results in a higher ordering temperature .

  13. Residual basins

    D'Elboux, C.V.; Paiva, I.B.

    1980-01-01

    Exploration for uranium carried out over a major portion of the Rio Grande do Sul Shield has revealed a number of small residual basins developed along glacially eroded channels of pre-Permian age. Mineralization of uranium occurs in two distinct sedimentary units. The lower unit consists of rhythmites overlain by a sequence of black shales, siltstones and coal seams, while the upper one is dominated by sandstones of probable fluvial origin. (Author) [pt

  14. Identification of HNF4A Mutation p.T130I and HNF1A Mutations p.I27L and p.S487N in a Han Chinese Family with Early-Onset Maternally Inherited Type 2 Diabetes

    Ying Yang

    2016-01-01

    Full Text Available Maturity-onset diabetes of the young (MODY is characterized by the onset of diabetes before the age of 25 years, positive family history, high genetic predisposition, monogenic mutations, and an autosomal dominant mode of inheritance. Here, we aimed to investigate the mutations and to characterize the phenotypes of a Han Chinese family with early-onset maternally inherited type 2 diabetes. Detailed clinical assessments and genetic screening for mutations in the HNF4α, GCK, HNF-1α, IPF-1, HNF1β, and NEUROD1 genes were carried out in this family. One HNF4A mutation (p.T130I and two HNF1A polymorphisms (p.I27L and p.S487N were identified. Mutation p.T130I was associated with both early-onset and late-onset diabetes and caused downregulated HNF4A expression, whereas HNF1A polymorphisms p.I27L and p.S487N were associated with the age of diagnosis of diabetes. We demonstrated that mutation p.T130I in HNF4A was pathogenic as were the predicted polymorphisms p.I27L and p.S487N in HNF1A by genetic and functional analysis. Our results show that mutations in HNF4A and HNF1A genes might account for this early-onset inherited type 2 diabetes.

  15. Methanol adsorption on Pt(111)

    Melo, A.V.; Chottiner, G.S.; Hoffman, R.W.; O'Grady, W.E.

    1984-12-01

    High resolution electron energy loss spectroscopy has been used to study the decomposition of methanol on a Pt(111) surface. Several intermediate states in the decomposition are identified by quenching the sample when reactions occur. At 100 K a set of peaks at 800, 1040, 1350, and 2890 cm -1 indicates the presence of a multilayer molecularly adsorbed methanol. As the sample is warmed to 130 K peaks develop at 1700 and 2780 cm -1 , suggesting the formation of formaldehyde on the surface. With further heating, peaks grow at 1820 and 2560 cm -1 due to the formation of a formyl species during the decomposition of methanol over Pt(111). Further heating leads to the final conversion of the surface species to adsorbed CO and carbonaceous residues

  16. Prothrombin time (PT)

    PT; Pro-time; Anticoagulant-prothrombin time; Clotting time: protime; INR; International normalized ratio ... PT is measured in seconds. Most of the time, results are given as what is called INR ( ...

  17. Integrated project: Microbiological and physiological studies on the presence of residual concentrations in mineral-oil-contaminated soils after rehabilitation. Final report. Pt. 2; Mikrobiologische und physiologische Untersuchungen zur Frage der Restkonzentration bei der Sanierung mineraloelkontaminierter Boeden. Abschlussbericht. T. 2

    Miethe, D.; Riis, V.; Stimming, M.

    1996-01-04

    It has been known for a long time that microorganisms are able to utilise mineral oils. Today various methods are practised which exploit autochthonous microorganisms` ability to utilise mineral oils. The main problem of microbial decomposition of hydrocarbons is that mineral oil residues remain. The aim of the present research project was therefore to determine the limits of the metabolisability of the substrate and find out why residues remain. Mineral oils and residual fractions differ markedly in their decomposability. Intermediate distillates are easily decomposed to a degree of 95-97% by well-adapted consorts. For high-boiling mineral oils (bp>400 C) the degree of decomposition is approx. 60%. Extracts from contaminated sites range from 40 to 60% in their degree of decomposability. The incomplete microbial decomposition of mineral oils is mainly due to their structure. There remain chemically and thermally extremely, inert hydrocarbons (mainly aliphatic and aromatic fused-ring systems) which are either hardly metabolisable or not at all. An important factor in soils or at other contaminated sites is that some of the substrate is not available because it is bound to the matrix thus increasing the proportion of residue. The next task after examining and presenting the causes of incomplete decomposition is to minimise residual mineral oil concentrations remaining after microbial decomposition. Here the use of special surfactants or of auxiliary substrates could point a way. Project applications to this end have already been submitted to the Federal Ministry for Education and Research. (orig.) [Deutsch] Dass Mikroorganismen in der Lage sind, Mineraloele zu verwerten, ist seit langem bekannt. Verfahren, die das Potential autochthoner Mikroorganismen zur Verwertung von Mineraloelen nutzen sind Praxis. Hauptproblem beim mikrobiellen Abbau der Kohlenwasserstoffe ist das Verbleiben von Mineraloelresten. Das Ziel des Forschungsvorhabens war die Ermittlung der Grenzen

  18. Epitaxial growth of zigzag PtAu alloy surface on Au nano-pentagrams with enhanced Pt utilization and electrocatalytic performance toward ethanol oxidation reaction

    Du, Cheng; Gao, Xiaohui; Zhuang, Zhihua; Cheng, Chunfeng; Zheng, Fuqin; Li, Xiaokun; Chen, Wei

    2017-01-01

    Highlights: • PtAu nanoalloy surface is heteroepitaxially grown on the pre-synthesized Au nano-pentagrams. • The PtAu/Au nano-pentagrams exhibit excellent electrocatalytic activity for ethanol oxidation. • The charge transfer resistance of PtAu/Au is lower than that of commercial Pt/C. • The durability and anti-poisoning ability of PtAu/Au is much better than those of commercial Pt/C - Abstract: Improving Pt utilization is of fundamental importance for many significant processes in energy conversion, which is strongly dependent on the surface structure of used catalysts. Based on the traditional Pt-on-Au system which has been proved to be an ideal nanostructure for improving the catalytic activity and stability of Pt, and the recent follow-up studies on this system, we introduce here a new strategy for fabricating Pt surface with high-index facets over the Pt-on-Au system. To achieve this goal, we elaborately designed and fabricated a unique zigzag PtAu alloy nanosurface on Au nano-pentagrams (PtAu/Au NPs) through epitaxial growth of Pt along the high-index facets on the pre-synthesized Au nano-pentagrams. Owing to the surface electronic interaction between Au and Pt and the exposed high-index facets from the unique morphology of zigzag PtAu alloy nanosurface, the as-prepared PtAu/Au NPs exhibited excellent electrocatalytic performance toward ethanol oxidation reaction (EOR) in alkaline condition. The specific activity (8.3 mA cm"−"2) and mass activity (4.4 A mg"−"1) obtained from PtAu/Au NPs are about 5.2 and 5.5 times, respectively, higher than those from commercial Pt/C for EOR.

  19. PT and INR Test

    ... Plasma Free Metanephrines Platelet Count Platelet Function Tests Pleural Fluid Analysis PML-RARA Porphyrin Tests Potassium Prealbumin ... and vitamin K (either in a multivitamin or liquid nutrition supplement) may decrease PT. Certain foods, such ...

  20. Progress in biogas. Biogas production from agricultural biomass and organic residues. Pt. 1 and 2. Proceedings (oral presentations and poster presentations); Fortschritt beim Biogas. Biogas aus landwirtschaftlicher Biomasse and organischen Reststoffen. T. 1 und 2. Tagungsband. Vortraege and Poster

    NONE

    2007-07-01

    Within the International Conference ''Progress in Biogas - Biogas production from agricultural biomass and organic residues'' at the University Hohenheim (Stuttgart, Federal Republic of Germany) from 18th to 21st September, 2007, the following lectures were held: (1) Global relevance and potential of bioenergy for regional development; (2) Biogas electricity for France feed-in tariff and some other things to know before entering French market; (3) Policy drivers and future prospects for on-farm anaerobic digestion in Northern Ireland; (4) Biogas in Belgium, a swot analysis; (5) Status and prospects of biogas energy use in Ukraine; (6) Recent developments in Chinese agricultural biogas production; (7) Opportunities for agricultural based biogas systems in the province of Ontario, Canada; (8) Pre-treatment and digestion of separated collected household waste in Sweden; (9) To the problem of monitoring measures and prophylaxis measures with the utilization of organic residual substances in biological gas facilities from hygienic view; (10) Fermenting residues from biological gas facilities - nutrients and pollutants, possibilities of application in the agriculture; (11) Treatment and utilization of fermentation residues; (12) Potential of residual gas of NaWaRo feeded biogas plants in Baden-Wuerttemberg; (13) Operating analytics of biogas plants to improve efficiency and to ensure process stability; (14) The potential of biogas and electric power production from subproducts in the sugar and alcohol industries by the application of anaerobic digestion; (15) Co-digestion plant in dairy cattle farm in Emilia Romagna region (Italy); (16) Facing operational problems in a biodigeser in Yuvientsa - Amazonian Region of Ecuador; (17) Biogas plant instead of milk cow - payment and occupation with the use of grassilage; (18) Biogas in ecologic agriculture - experiences from 3 years of fermentation of grass-clover ley; (19) Combined solar-biogas basis for the

  1. Progress in biogas. Biogas production from agricultural biomass and organic residues. Pt. 1 and 2. Proceedings (oral presentations and poster presentations); Fortschritt beim Biogas. Biogas aus landwirtschaftlicher Biomasse and organischen Reststoffen. T. 1 und 2. Tagungsband. Vortraege and Poster

    NONE

    2007-07-01

    Within the International Conference ''Progress in Biogas - Biogas production from agricultural biomass and organic residues'' at the University Hohenheim (Stuttgart, Federal Republic of Germany) from 18th to 21st September, 2007, the following lectures were held: (1) Global relevance and potential of bioenergy for regional development; (2) Biogas electricity for France feed-in tariff and some other things to know before entering French market; (3) Policy drivers and future prospects for on-farm anaerobic digestion in Northern Ireland; (4) Biogas in Belgium, a swot analysis; (5) Status and prospects of biogas energy use in Ukraine; (6) Recent developments in Chinese agricultural biogas production; (7) Opportunities for agricultural based biogas systems in the province of Ontario, Canada; (8) Pre-treatment and digestion of separated collected household waste in Sweden; (9) To the problem of monitoring measures and prophylaxis measures with the utilization of organic residual substances in biological gas facilities from hygienic view; (10) Fermenting residues from biological gas facilities - nutrients and pollutants, possibilities of application in the agriculture; (11) Treatment and utilization of fermentation residues; (12) Potential of residual gas of NaWaRo feeded biogas plants in Baden-Wuerttemberg; (13) Operating analytics of biogas plants to improve efficiency and to ensure process stability; (14) The potential of biogas and electric power production from subproducts in the sugar and alcohol industries by the application of anaerobic digestion; (15) Co-digestion plant in dairy cattle farm in Emilia Romagna region (Italy); (16) Facing operational problems in a biodigeser in Yuvientsa - Amazonian Region of Ecuador; (17) Biogas plant instead of milk cow - payment and occupation with the use of grassilage; (18) Biogas in ecologic agriculture - experiences from 3 years of fermentation of grass-clover ley; (19) Combined solar-biogas basis for the population social

  2. Structure and chemical composition of supported Pt-Sn electrocatalysts for ethanol oxidation

    Jiang Luhua; Sun Gongquan; Sun Shiguo; Liu Jianguo; Tang Shuihua; Li Huanqiao; Zhou Bing; Xin Qin

    2005-01-01

    Carbon supported PtSn alloy and PtSnO x particles with nominal Pt:Sn ratios of 3:1 were prepared by a modified polyol method. High resolution transmission electron microscopy (HRTEM) and X-ray microchemical analysis were used to characterize the composition, size, distribution, and morphology of PtSn particles. The particles are predominantly single nanocrystals with diameters in the order of 2.0-3.0 nm. According to the XRD results, the lattice constant of Pt in the PtSn alloy is dilated due to Sn atoms penetrating into the Pt crystalline lattice. While for PtSnO x nanoparticles, the lattice constant of Pt only changed a little. HRTEM micrograph of PtSnO x clearly shows that the change of the spacing of Pt (1 1 1) plane is neglectable, meanwhile, SnO 2 nanoparticles, characterized with the nominal 0.264 nm spacing of SnO 2 (1 0 1) plane, were found in the vicinity of Pt particles. In contrast, the HRTEM micrograph of PtSn alloy shows that the spacing of Pt (1 1 1) plane extends to 0.234 nm from the original 0.226 nm. High resolution energy dispersive X-ray spectroscopy (HR-EDS) analyses show that all investigated particles in the two PtSn catalysts represent uniform Pt/Sn compositions very close to the nominal one. Cyclic voltammograms (CV) in sulfuric acid show that the hydrogen ad/desorption was inhibited on the surface of PtSn alloy compared to that on the surface of the PtSnO x catalyst. PtSnO x catalyst showed higher catalytic activity for ethanol electro-oxidation than PtSn alloy from the results of chronoamperometry (CA) analysis and the performance of direct ethanol fuel cells (DEFCs). It is deduced that the unchanged lattice parameter of Pt in the PtSnO x catalyst is favorable to ethanol adsorption and meanwhile, tin oxide in the vicinity of Pt nanoparticles could offer oxygen species conveniently to remove the CO-like species of ethanolic residues to free Pt active sites

  3. Microwave-assisted synthesis of high-loading, highly dispersed Pt ...

    Keywords. Direct methanol fuel cell; carbon aerogel; Pt; microwave-assisted polyol process; electrocatalyst; ... obtained from the carbonization of the dried organic aero- gel in a ... 12 hours. The dried residue (0·01 g) was mixed with ethanol.

  4. Residual stresses

    Sahotra, I.M.

    2006-01-01

    The principal effect of unloading a material strained into the plastic range is to create a permanent set (plastic deformation), which if restricted somehow, gives rise to a system of self-balancing within the same member or reaction balanced by other members of the structure., known as residual stresses. These stresses stay there as locked-in stresses, in the body or a part of it in the absence of any external loading. Residual stresses are induced during hot-rolling and welding differential cooling, cold-forming and extruding: cold straightening and spot heating, fabrication and forced fitting of components constraining the structure to a particular geometry. The areas which cool more quickly develop residual compressive stresses, while the slower cooling areas develop residual tensile stresses, and a self-balancing or reaction balanced system of residual stresses is formed. The phenomenon of residual stresses is the most challenging in its application in surface modification techniques determining endurance mechanism against fracture and fatigue failures. This paper discusses the mechanism of residual stresses, that how the residual stresses are fanned and what their behavior is under the action of external forces. Such as in the case of a circular bar under limit torque, rectangular beam under limt moment, reclaiming of shafts welds and peening etc. (author)

  5. Progress in biogas II - Biogas production from agricultural biomass and organic residues. Pt. 1. Proceedings; Progress in Biogas II - Biogasproduktion aus landwirtschaftlicher Biomasse und organischen Reststoffen. T. 1. Tagungsband

    NONE

    2011-08-12

    production - Methabe yield and energy balance (R. Bolduan); (19) Evaluation of a pre-treatment process for improved methane production from grass silage (A. Orozco); (20) Anaerobic fungi and biogas production (J. Prochazka); (21) Preservation of sugar beets for biogas production (A. Wagner); (22) Fibre, biogas and compost from banana agro-residues (leaves, pseudostem and rachis) by anaerobic digestion in plug flow type digester (H. Chanakya); (23) Extraction of biogas from waste products of he sugarcane industry (J. Rietzler); (24) Practical experiences with the digestion of straw in 2-stage AD plants - Extension of the value chain (W. Danner); (25) Improving biogas production on wastewater treatment plants by co-digestion of grass (D. Klein); (26) Generation of algal biomass for biogas production: energetic and environmental from a Life Cycle Assessment (LCA) perspective (F. Romagnoli); (27) Risk reduction in spreading plant pathogens by anaerobic digestion? First results from laboratory experiments (M. Heiermann); (28) Demand-oriented biogas production for the generation of peak load (R. Wallmann); (29) Investigation of mesophilic and thermophilic bioleaching method in a two-phase anaerobic digestion process (M. Schoenberg): (30) Efficient hydrogen fermentation for 2-stage anaerobic digestion processes: Conversion of sucrose containing substrates (S. Noebauer); (31) Process development of two-phase pressure formation - Influence of gas solubilities (A.-M. Wonneberger); (32) Benefits and limitations when treating liquid pig manure in an anaerobic membrane bioreactor (P. Messerl); (33) Experiences with continuous high-rate thermophilic dry anaerobic digestion of energy crops (L. De Baere); (34) The Sauter-biogas-system: spraying instead of stirring (S. Sauter); (35) Biogas production from raw palm oil mill effluent using a pilot-scale anaerobic hybrid reactor (C. Wangnai); (36) Eta max - the biogas power plant with high biological efficiency (M. Niederbacher); (37) Long time

  6. Progress in biogas II - Biogas production from agricultural biomass and organic residues. Pt. 1. Proceedings; Progress in Biogas II - Biogasproduktion aus landwirtschaftlicher Biomasse und organischen Reststoffen. T. 1. Tagungsband

    NONE

    2011-08-12

    biogas production - Methabe yield and energy balance (R. Bolduan); (19) Evaluation of a pre-treatment process for improved methane production from grass silage (A. Orozco); (20) Anaerobic fungi and biogas production (J. Prochazka); (21) Preservation of sugar beets for biogas production (A. Wagner); (22) Fibre, biogas and compost from banana agro-residues (leaves, pseudostem and rachis) by anaerobic digestion in plug flow type digester (H. Chanakya); (23) Extraction of biogas from waste products of he sugarcane industry (J. Rietzler); (24) Practical experiences with the digestion of straw in 2-stage AD plants - Extension of the value chain (W. Danner); (25) Improving biogas production on wastewater treatment plants by co-digestion of grass (D. Klein); (26) Generation of algal biomass for biogas production: energetic and environmental from a Life Cycle Assessment (LCA) perspective (F. Romagnoli); (27) Risk reduction in spreading plant pathogens by anaerobic digestion? First results from laboratory experiments (M. Heiermann); (28) Demand-oriented biogas production for the generation of peak load (R. Wallmann); (29) Investigation of mesophilic and thermophilic bioleaching method in a two-phase anaerobic digestion process (M. Schoenberg): (30) Efficient hydrogen fermentation for 2-stage anaerobic digestion processes: Conversion of sucrose containing substrates (S. Noebauer); (31) Process development of two-phase pressure formation - Influence of gas solubilities (A.-M. Wonneberger); (32) Benefits and limitations when treating liquid pig manure in an anaerobic membrane bioreactor (P. Messerl); (33) Experiences with continuous high-rate thermophilic dry anaerobic digestion of energy crops (L. De Baere); (34) The Sauter-biogas-system: spraying instead of stirring (S. Sauter); (35) Biogas production from raw palm oil mill effluent using a pilot-scale anaerobic hybrid reactor (C. Wangnai); (36) Eta max - the biogas power plant with high biological efficiency (M. Niederbacher); (37

  7. Residual stresses

    Macherauch, E.

    1978-01-01

    Residual stresses are stresses which exist in a material without the influence of external powers and moments. They come into existence when the volume of a material constantly changes its form as a consequence of mechanical, thermal, and/or chemical processes and is hindered by neighbouring volumes. Bodies with residual stress are in mechanical balance. These residual stresses can be manifested by means of all mechanical interventions disturbing this balance. Acoustical, optical, radiological, and magnetical methods involving material changes caused by residual stress can also serve for determining residual stress. Residual stresses have an ambivalent character. In technical practice, they are feared and liked at the same time. They cause trouble because they can be the cause for unexpected behaviour of construction elements. They are feared since they can cause failure, in the worst case with catastrophical consequences. They are appreciated, on the other hand, because, in many cases, they can contribute to improvements of the material behaviour under certain circumstances. But they are especially liked for their giving convenient and (this is most important) mostly uncontrollable explanations. For only in very few cases we have enough knowledge and possibilities for the objective evaluation of residual stresses. (orig.) [de

  8. Pt, Co–Pt and Fe–Pt alloy nanoclusters encapsulated in virus capsids

    Okuda, M; Eloi, J-C; Jones, S E Ward; Schwarzacher, W; Verwegen, M; Cornelissen, J J L M

    2016-01-01

    Nanostructured Pt-based alloys show great promise, not only for catalysis but also in medical and magnetic applications. To extend the properties of this class of materials, we have developed a means of synthesizing Pt and Pt-based alloy nanoclusters in the capsid of a virus. Pure Pt and Pt-alloy nanoclusters are formed through the chemical reduction of [PtCl 4 ] − by NaBH 4 with/without additional metal ions (Co or Fe). The opening and closing of the ion channels in the virus capsid were controlled by changing the pH and ionic strength of the solution. The size of the nanoclusters is limited to 18 nm by the internal diameter of the capsid. Their magnetic properties suggest potential applications in hyperthermia for the Co–Pt and Fe–Pt magnetic alloy nanoclusters. This study introduces a new way to fabricate size-restricted nanoclusters using virus capsid. (paper)

  9. Antagonistic Activities of Novel Peptides from Bacillus amyloliquefaciens PT14 against Fusarium solani and Fusarium oxysporum.

    Kim, Young Gwon; Kang, Hee Kyoung; Kwon, Kee-Deok; Seo, Chang Ho; Lee, Hyang Burm; Park, Yoonkyung

    2015-12-09

    Bacillus species have recently drawn attention due to their potential use in the biological control of fungal diseases. This paper reports on the antifungal activity of novel peptides isolated from Bacillus amyloliquefaciens PT14. Reverse-phase high-performance liquid chromatography revealed that B. amyloliquefaciens PT14 produces five peptides (PT14-1, -2, -3, -4a, and -4b) that exhibit antifungal activity but are inactive against bacterial strains. In particular, PT14-3 and PT14-4a showed broad-spectrum antifungal activity against Fusarium solani and Fusarium oxysporum. The PT14-4a N-terminal amino acid sequence was identified through Edman degradation, and a BLAST homology analysis showed it not to be identical to any other protein or peptide. PT14-4a displayed strong fungicidal activity with minimal inhibitory concentrations of 3.12 mg/L (F. solani) and 6.25 mg/L (F. oxysporum), inducing severe morphological deformation in the conidia and hyphae. On the other hand, PT14-4a had no detectable hemolytic activity. This suggests PT14-4a has the potential to serve as an antifungal agent in clinical therapeutic and crop-protection applications.

  10. Ultrathin Pt films on Ni(111): Structure determined by surface x-ray diffraction

    Robach, O.; Isern, H.; Quiros, C.; Ferrer, S.; Steadman, P.; Peters, K. F.

    2003-01-01

    The growth of platinum on a nickel (111) single crystal under ultrahigh vacuum conditions was studied using surface x-ray diffraction on the ID03 beamline of the ESRF. Film thickness ranged from one to eight monoatomic layers (ML). Specular reflectivity was used to determine the growth mode and vertical lattice parameter of the Pt film. A two-dimensional (2D) growth up to 1 ML followed by more 3D growth was found. A small expansion of the Pt vertical lattice parameter was found. The Pt in-plane lattice parameter was measured. Its relaxation was found to be very slow, with a residual contraction of 2.3% in an 8-ML-thick film (with respect to bulk Pt). A Ni crystal truncation rod measured before and after growing 1 ML of Pt revealed the presence of a small amount of pseudomorphic Pt, adsorbed on both fcc and hcp sites. The stacking of the (111) Pt planes was investigated by measuring stacking-sensitive Pt diffraction rods. A strong tendency to stacking reversal was found at room temperature, with an amount of 'reversed' Pt about ten times higher than the amount of Pt with the same stacking as the Ni. An eight-layer Ni film on Pt(111) was also studied for comparison

  11. Solid residues

    Mulder, E.; Duin, P.J. van; Grootenboer, G.J.

    1995-01-01

    A summary is presented of the many investigations that have been done on solid residues of atmospheric fluid bed combustion (AFBC). These residues are bed ash, cyclone ash and bag filter ash. Physical and chemical properties are discussed and then the various uses of residues (in fillers, bricks, gravel, and for recovery of aluminium) are summarised. Toxicological properties of fly ash and stack ash are discussed as are risks of pneumoconiosis for workers handling fly ash, and contamination of water by ashes. On the basis of present information it is concluded that risks to public health from exposure to emissions of coal fly ash from AFBC appear small or negligible as are health risk to workers in the coal fly ash processing industry. 35 refs., 5 figs., 12 tabs

  12. Characterization of azo dyes on Pt and Pt/polyaniline/dispersed Pt electrodes

    Molina, J.; Fernandez, J.; Rio, A.I. del; Bonastre, J. [Departamento de Ingenieria Textil y Papelera, EPS de Alcoy, Universitat Politecnica de Valencia, Plaza Ferrandiz y Carbonell s/n, 03801 Alcoy (Spain); Cases, F., E-mail: fjcases@txp.upv.es [Departamento de Ingenieria Textil y Papelera, EPS de Alcoy, Universitat Politecnica de Valencia, Plaza Ferrandiz y Carbonell s/n, 03801 Alcoy (Spain)

    2012-06-15

    The electrochemical characterization of two organic dyes (amaranth and procion orange MX-2R) has been performed on Pt electrodes and Pt electrodes coated with polyaniline and dispersed Pt. Electrodes with different Pt loads have been synthesized and characterized obtaining that a load of 300 {mu}g cm{sup -2} was the optimum one. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) was employed to observe the distribution and morphology of the Pt nanoparticles. The electroactivity of the electrodes has also been characterized by means of scanning electrochemical microscopy (SECM). The chemical characterization of Pt dispersed Pani coated Pt electrodes (Pt-Pani-Pt) was performed by means of X-ray photoelectron spectroscopy (XPS). The electrochemical characterization of the dyes has been performed by means of cyclic voltammetry. Voltammograms have shown that the presence of the dyes diminishes characteristic Pt oxidation and reduction peaks. However, redox processes due to the dyes, appeared in the voltammograms. The different species responsible of these redox processes were generated in the vicinity of the electrode and were not adsorbed on the electrode surface since after stirring, the different redox processes disappeared. Characterization with different scan rates showed that redox processes of both dyes were controlled by diffusion.

  13. Evaluating the residual stress in PbTiO3 thin films prepared by a polymeric chemical method

    Valim, D; Filho, A G Souza; Freire, P T C; Filho, J Mendes; Guarany, C A; Reis, R N; Araujo, E B

    2004-01-01

    We report a study of residual stress in PbTiO 3 (PT) thin films prepared on Si substrates by a polymeric chemical method. The E(1TO) frequency was used to evaluate the residual stress through an empirical equation available for bulk PT. We find that the residual stress in PT films increases as the film thickness decreases and conclude that it originates essentially from the contributions of extrinsic and intrinsic factors. Polarized Raman experiments showed that the PT films prepared by a polymeric chemical method are somewhat a-domain (polar axis c parallel to the substrate) oriented

  14. Coulomb excitation of the 4+1 states of 194Pt, 196Pt and 198Pt

    Fewell, M.P.; Gyapong, G.J.; Spear, R.H.

    1987-09-01

    Probabilities for the Coulomb excitation of the 4 1 + states of 194 Pt, 196 Pt, 198 Pt by the backscattering of 4 He, 12 C and 16 O ions are reported. Model-independent values of the matrix elements 1 + ; M(E4), 4 1 + > and 1 + , M(E2), 4 1 + > are extracted. Agreement with previous measurements of these matrix elements is good. Values of β 2 and β 4 are determined for 194 Pt and compared with calculations of these quantities

  15. Electrochemical oxidation of methanol on Pt/(RuxSn1-xO2 nanocatalyst

    Krstajić Mila N.

    2013-01-01

    Full Text Available The Ru-doped SnO2 powder, (RuxSn1-xO2, with the Sn:Ru atomic ratio of 9:1 was synthesized and used as a support for Pt nanoparticles (30 mass% loading. The (RuxSn1-xO2 support and Pt/(RuxSn1-xO2 catalyst were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and transmission electron microscopy (TEM. (RuxSn1-xO2 was found to be two-phase material consisting of probably solid solution of RuO2 in SnO2 and pure RuO2. The average Pt particle size determined by TEM was 5.3 nm. Cyclic voltammetry of Pt/(RuxSn1-xO2 indicated good conductivity of the sup-port and displayed usual features of Pt. The results of the electrochemical oxidation of COads and methanol on Pt/(RuxSn1-xO2 were compared with those on commercial Pt/C and PtRu/C catalysts. Oxidation of COads on Pt/(RuxSn1-xO2 starts at less positive potentials than on PtRu/C and Pt/C. Potentiodynamic polarization curves and chronoamperometric curves of methanol oxidation indicated higher initial activity of Pt/(RuxSn1-xO2 catalyst compared to PtRu/C, but also a greater loss in the current density over time. Potentiodynamic stability test of the catalysts revealed that deactivation of the Pt/(RuxSn1-xO2 and Pt/C was primarily caused by the poisoning of Pt surface by the methanol oxidation residues, which mostly occurred during the first potential cycle. In the case of PtRu/C the poisoning of the surface was minor and deactivation was caused by the PtRu surface area loss. [Projekat Ministarstva nauke Republike Srbije, br. ON-172054

  16. Residual nilpotence and residual solubility of groups

    Mikhailov, R V

    2005-01-01

    The properties of the residual nilpotence and the residual solubility of groups are studied. The main objects under investigation are the class of residually nilpotent groups such that each central extension of these groups is also residually nilpotent and the class of residually soluble groups such that each Abelian extension of these groups is residually soluble. Various examples of groups not belonging to these classes are constructed by homological methods and methods of the theory of modules over group rings. Several applications of the theory under consideration are presented and problems concerning the residual nilpotence of one-relator groups are considered.

  17. Food poisoning. Pt. 2

    Askar, A.; Treptow, H.

    1982-01-15

    In the present study information about food poisoning is compared and reviewed. From the viewpoint of a food technologist the toxic substances are represented in four sections: 1. Residues of substances used by plants and animals: pesticides, antibiotics, sexual hormones and psychopharmaces. 2. Environmental contaminants: heavy metals, radionuclides and polycyclic hydrocarbons. 3. Substances developing during the manufacture: food additives, asbest, parts of packing materials, and residual solvents. 4. Substances arising from processing: smoked and roasted food, non enzymatic reaction, oxidized and heated fats and irradiated foods. The mere presence of toxic substances does not make food unsafe or poisonous. Dangerous, because of their toxic or carcinogenic effects are: Pesticides (especially chlorinated organic pesticides), heavy metals (especially lead, mercury and cadmium), polycyclic hydrocarbons (3,4-benzpyren), nitrosamines and vinyl chloride. The other components are only dangerous if they are present in large ammounts. A good and responsible practise of agriculture and food manufacture processes, a watchful and competent official food control and well informed consumers can limit the danger of food poisoning and human health.

  18. Pt/C Fuel Cell Catalyst Degradation

    Zana, Alessandro

    This thesis investigates the degradation behavior of Pt/C catalysts under simulated automotive conditions. By using the “tool box” synthesis method the Pt loading has been changed from low to high Pt loadings, therefore permitting to study the role of Pt on the degradation of high surface area (H...

  19. Effect of Pt coverage in Pt-deposited Pd nanostructure electrodes on electrochemical properties

    Park, Ah-Reum; Lee, Young-Woo; Kwak, Da-Hee; Park, Kyung-Won [Soongsil University, Seoul (Korea, Republic of)

    2015-06-15

    We have fabricated Pt-deposited Pd electrodes via a two-gun sputtering deposition system by separately operating Pd and Pt target as a function of sputtering time of Pt target. For Pt-deposited Pd electrodes (Pd/Pt-X), Pd were first deposited on the substrates at 20 W for 5min, followed by depositing Pt on the Pd-only electrodes as a function of sputtering time (X=1, 3, 5, 7, and 10min) at 20W on the Pt target. As the sputtering time of Pt target increased, the portion of Pt on the Pd electrodes increased, representing an increased coverage of Pt on the Pd electrodes. The Pd/Pt-7 electrode having an optimized Pt coverage exhibits an excellent electrocatalytic activity for methanol oxidation reaction.

  20. Water quality. Pt. 3

    1993-01-01

    This International Standard specifies a method for the determination of gross alpha activity in non-saline waters for alpha-emitting radionuclides which are not volatile at 350 o C. It is possible to determine supported volatile radionuclides measured to an extent determined by half-life, matrix retention (of the volatile species) and the duration of measurement (counting time). The method is applicable to raw and potable waters and can be extended to saline or mineralized waters, but with a reduced sensitivity. The range of application depends on the amount of inorganic material in the water and on the performance characteristics (background count rate and counting efficiency) of the counter. The sample is acidified to stabilize it, evaporated almost to dryness, converted to the sulfate form and then ignited at 350 o C. A portion of the residue is transferred to a planchette and the alpha activity measured by counting in an alpha-particle detector or counting system previously calibrated against an alpha-emitting standard. (author)

  1. A further insight into the biosorption mechanism of Pt(IV by infrared spectrometry

    Xu Zhenling

    2009-07-01

    Full Text Available Abstract Background Platinum nanomaterial is one of the significant noble metal catalysts, and the interaction of platinum with microbe is one of the key factors in influencing the size and the distribution of the platinum nanoparticles on the microbial biomass. Some properties of Pt(IV adsorption and reduction by resting cells of Bacillus megatherium D01 biomass have once been investigated, still the mechanism active in the platinum biosorption remains to be seen and requires further elucidating. Result A further insight into the biosorption mechanism of Pt(IV onto resting cells of Bacillus megatherium D02 biomass on a molecular level has been obtained. The image of scanning electron microscopy (SEM of the D02 biomass challenged with Pt(IV displayed a clear distribution of bioreduced platinum particles with sizes of nanometer scale on the biomass. The state of Pt(IV bioreduced to elemental Pt(0 examined via X-ray photoelectron spectroscopy (XPS suggested that the biomass reduces the Pt(IV to Pt(II followed by a slower reduction to Pt(0. The analysis of glucose content in the hydrolysates of D02 biomass for different time intervals using ultraviolet-visible (UV-vis spectrophotometry indicated that certain reducing sugars occur in the hydrolyzed biomass and that the hydrolysis of polysaccharides of the biomass is a rapid process. The infrared (IR spectrometry on D02 biomass and that challenged with Pt(IV, and on glucose and that reacted with Pt(IV demonstrated that the interaction of the biomass with Pt(IV seems to be through oxygenous or nitrogenous chemical functional groups on the cell wall biopolymers; that the potential binding sites for Pt species include hydroxyl of saccharides, carboxylate anion and carboxyl of amino acid residues, peptide bond, etc.; and that the free monosaccharic group bearing hemiacetalic hydroxyl from the hydrolyzed biomass behaving as an electron donor, in situ reduces the Pt(IV to Pt(0. And moreover, the binding of

  2. Ab-initio study of the coadsorption of Li and H on Pt(001), Pt(110) and Pt(111) surfaces

    Saad, Farida [Laboratoire de Physique et Chimie Quantique, Faculte des Sciences, Universite Mouloud Mammeri, 15000 Tizi-Ouzou (Algeria); Zemirli, Mourad, E-mail: zemirlimourad@mail.ummto.dz [Laboratoire de Physique et Chimie Quantique, Faculte des Sciences, Universite Mouloud Mammeri, 15000 Tizi-Ouzou (Algeria); Benakki, Mouloud; Bouarab, Said [Laboratoire de Physique et Chimie Quantique, Faculte des Sciences, Universite Mouloud Mammeri, 15000 Tizi-Ouzou (Algeria)

    2012-02-15

    The coadsorption of Li and H atoms on Pt(001), Pt(110) and Pt(111) surfaces is studied using density functional theory with generalised gradient approximation. In all calculations Li, H and the two topmost layers of the metal were allowed to relax. At coverage of 0.25 mono-layer in a p(2 Multiplication-Sign 2) unit cell, lithium adsorption at the hollow site for the three surfaces is favoured over top and bridge sites. The most favoured adsorption sites for H atom on the Pt(001) and Pt(110) surfaces are the top and bridge sites, while on Pt(111) surface the fcc site appears to be slightly favoured over the hcp site. The coadsorption of Li and atomic hydrogen shows that the interaction between the two adsorbates is stabilising when they are far from each other. The analysis of Li, H and Pt local density of states shows that Li strongly interacts with the Pt surfaces.

  3. Consumption of Pt anode in phosphoric acid

    Kamiya, N.; Urata, K.; Motohira, N.; Ota, K. [Yokohama National University, Yokohama (Japan)

    1997-12-05

    Consumption of Pt anode was investigated in phosphoric acid of various concentration. In 30-70wt% phosphoric acid, Pt dissolved at the rate of 19{mu}gcm{sup -2}h{sup -1}. On the other hand, in 85 wt% phosphoric acid, the amount increased to 0.91 mgcm{sup -2}h{sup -1} which is ca. 180 and 1800 times as much as in 1M sulfuric acid and 1M alkaline solution, respectively. In the diluted phosphoric acid solution, the Pt surface was covered with Pt oxides during the electrolysis, which would prevent the surface from corrosion. However, in the concentrated phosphoric acid, no such oxide surface was observed. Concentrated phosphoric acid might form stable complex with Pt species, therefore the uncovered bare Pt surface is situated in the serious corrosion condition under the high overvoltage and Pt would dissolve into the solution directly instead of forming the Pt oxides. 11 refs., 9 figs., 1 tab.

  4. Magnetism and superconductivity of CePt3Si and Ce1+xPt3+ySi1+z

    Motoyama, Gaku; Yamamoto, Suguru; Takezoe, Hiroaki; Oda, Yasukage; Ueda, Ko-ichi; Kohara, Takao

    2006-01-01

    We measured the dc magnetization, electrical resistivity, and ac magnetic susceptibility of a series of polycrystalline CePt 3 Si samples whose compositions vary slightly from the stoichiometric composition. The sample that showed the most distinct anitiferromagnetic transition at 2.2K was found to be Ce 1.01 Pt 3 Si annealed. This sample showed a clear bulk antiferromagnetic order at 2.2 K even in both electrical resistivity and dc magnetization measurements, although the characteristic change in dc magnetization at 2.2 K was found to be small and to be easily masked in other magnetic anomalies if they exist. Moreover, it had the largest residual resistivity ratio. We concluded that Ce 1.01 Pt 3 Si annealed has the intrinsic bulk properties of ideal CePt 3 Si. In addition, we revealed that some anomalies arise as a result of the variation in composition. One is a ferromagnetic anomaly at 3.0 K in the Pt-rich samples, and the other is an antiferromagnetic anomaly at 4.0 K in the Pt-poor samples. The two magnetic anomalies seemed to appear in small domains in the samples that exhibited an antiferromagnetic order at 2.2 K. To reveal the relationship between these magnetisms and superconductivity, we measured ac magnetic susceptibility down to ∼14mK. We found that the superconducting transition temperature is suppressed by the ferromagnetic anomaly. (author)

  5. Perancangan Promosi Digital PT Campina Di Surabaya

    Wijaya, Fernando; Hartanto, Deddi Duto; Sylvia, Merry

    2013-01-01

    Perancangan ini dilakukan untuk mempromosikan PT. Campina Ice Cream Industry beserta produknya. PT. Campina Ice Cream Industry diangkat sebagai topic perancangan karena banyak competitor-kompetitor yang bermunculan. Dengan melihat berbagai kelebihan dan kekurangan PT. Campina Ice Cream Industry, promosi dirancang agar dapat menggambarkan kelebihan PT. Campina Ice Cream Industry. Sehingga diharapkan dapat mengingatkan kembali ice cream Campina dalam benak konsumen. Untuk media promosi digital...

  6. Strategic Alliance Between PT Dirgantara Indonesia and Airbus Millitary (a Case Study of PT Dirgantara Indonesia)

    Indriyanto, Reza Relen; Wandebori, Harimukti; Astuti, Novika Candra

    2013-01-01

    PT Dirgantara Indonesia (PT DI) is one of the aircraft manufacturing companies in Indonesia. The tight of competition in aerospace industry needs to improve its performance to gain niche market. Therefore, Ministry State of Own Enterprises has instructed PT Perusahaan Pengelola Aset (PT PPA) and PT DI to restructure and revitalize company with supported by Airbus Military as a strategic alliance partner, in order to increase the performance of production capacity, aircraft sales, and financia...

  7. Properties and electrochemical behaviors of AuPt alloys prepared by direct-current electrodeposition for lithium air batteries

    Zhang, Jinqiu; Li, Da; Zhu, Yiming; Chen, Miaomiao; An, Maozhong; Yang, Peixia; Wang, Peng

    2015-01-01

    AuPt catalyst has a prospective application in a lithium air battery because of its bi-function on catalyzing Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER). Electrodeposition is an in-situ convenient technology for catalyst preparation without chemical residue. In an acid electrolyte, AuPt alloy catalysts were electrodeposited on carbon paper. The effect of main salt concentration, electrodeposition time and current density were studied by deposit micromorphology observation, structure analyses and composition testing. Catalytic abilities of AuPt alloys were measured by cyclic voltammetry (CV) in an ionic liquid of EMI-TFSI/Li-TFSI [1- Ethyl - 3- methylimidazolium–bis (trifluoromethanesulphonyl) imide/lithium–bis (trifluoromethanesulphonyl) imide]. The electrochemical behaviors of Au, Pt and AuPt deposits were also measured. An optimized direct-current electrodeposition process of getting high active AuPt catalyst is concluded, which is an aqueous solution containing 6.7∼10 mmol · L −1 HAuCl 4 , 10∼13.3 mmol · L −1 H 2 PtCl 6 and 0.5 mol · L −1 H 2 SO 4 as the electrolyte, current density of 20mA · cm −2 and electrodeposition time of 8∼34 s. The co-deposition of AuPt alloy is an irregular co-deposition controlled by diffusion, while gold atoms enter the platinum’s crystal lattice in the structure of AuPt alloy. The increase of the concentration of H 2 PtCl 6 in the electrolyte, the extension of the electrodeposition time or the raise of the current density can improve the content of Pt in the deposit. The clusters’ diameters of AuPt catalysts decrease to 150∼250 nm by adjusting current densities during electrodeposition

  8. Electronic structures of PtCu, PtAg, and PtAu molecules: a Dirac four-component relativistic study

    Abe, Minori; Mori, Sayaka; Nakajima, Takahito; Hirao, Kimihiko

    2005-01-01

    Relativistic four-component calculations at several correlated levels have been performed for diatomic PtCu, PtAg, and PtAu molecules. The ground state spectroscopic constants of PtCu were calculated using the four-component MP2 method, and show good agreement with experiment. We also performed calculations on the experimentally unknown species, PtAg and PtAu, and the mono-cationic systems, PtCu + , PtAg + , and PtAu + . The low-lying excited states of these diatomic molecules were also investigated using the four-component multi-reference CI method

  9. The anisotropy field of FePt L10 nanoparticles controlled by very thin Pt layer

    Okamoto, Satoshi; Kitakami, Osamu; Kikuchi, Nobuaki; Miyazaki, Takamichi; Shimada, Yutaka; Chiang, Te-Hsuan

    2004-01-01

    We have prepared epitaxial FePt L1 0 (001) nanoparticles covered with Pt [d Pt nm]/Ag[(4-d Pt ) nm] overlayers. The particles are oblate spheroids approximately 10 nm in diameter and 2 nm in height. The anisotropy field H k at 0 K, which is evaluated from the temperature dependences of coercivity H c , decreases from 90 to 60 kOe on increasing the Pt thickness from d Pt 0 to 1.5 nm, while the energy barrier at zero field remains unchanged. The significant reduction of H k due to the presence of the adjacent Pt layer can be attributed to an enhanced magnetic moment caused by the ferromagnetic polarization of Pt atoms at the interface. This finding suggests an effective method of controlling the switching field of FePt L1 0 nanoparticles

  10. Reversibility of Pt-Skin and Pt-Skeleton Nanostructures in Acidic Media.

    Durst, Julien; Lopez-Haro, Miguel; Dubau, Laetitia; Chatenet, Marian; Soldo-Olivier, Yvonne; Guétaz, Laure; Bayle-Guillemaud, Pascale; Maillard, Frédéric

    2014-02-06

    Following a well-defined series of acid and heat treatments on a benchmark Pt3Co/C sample, three different nanostructures of interest for the electrocatalysis of the oxygen reduction reaction were tailored. These nanostructures could be sorted into the "Pt-skin" structure, made of one pure Pt overlayer, and the "Pt-skeleton" structure, made of 2-3 Pt overlayers surrounding the Pt-Co alloy core. Using a unique combination of high-resolution aberration-corrected STEM-EELS, XRD, EXAFS, and XANES measurements, we provide atomically resolved pictures of these different nanostructures, including measurement of the Pt-shell thickness forming in acidic media and the resulting changes of the bulk and core chemical composition. It is shown that the Pt-skin is reverted toward the Pt-skeleton upon contact with acid electrolyte. This change in structure causes strong variations of the chemical composition.

  11. PT AND PT/NI "NEEDLE" ELETROCATALYSTS ON CARBON NANOTUBES WITH HIGH ACTIVITY FOR THE ORR

    Colon-Mercado, H.

    2011-11-10

    Platinum and platinum/nickel alloy electrocatalysts supported on graphitized (gCNT) or nitrogen doped carbon nanotubes (nCNT) are prepared and characterized. Pt deposition onto carbon nanotubes results in Pt 'needle' formations that are 3.5 nm in diameter and {approx}100 nm in length. Subsequent Ni deposition and heat treatment results in PtNi 'needles' with an increased diameter. All Pt and Pt/Ni materials were tested as electrocatalysts for the oxygen reduction reaction (ORR). The Pt and Pt/Ni catalysts showed excellent performance for the ORR, with the heat treated PtNi/gCNT (1.06 mA/cm{sup 2}) and PtNi/nCNT (0.664 mA/cm{sup 2}) showing the highest activity.

  12. Low Pt content direct methanol fuel cell anode catalyst: nanophase PtRuNiZr

    Narayanan, Sekharipuram R. (Inventor); Whitacre, Jay F. (Inventor)

    2010-01-01

    A method for the preparation of a metallic material having catalytic activity that includes synthesizing a material composition comprising a metal content with a lower Pt content than a binary alloy containing Pt but that displays at least a comparable catalytic activity on a per mole Pt basis as the binary alloy containing Pt; and evaluating a representative sample of the material composition to ensure that the material composition displays a property of at least a comparable catalytic activity on a per mole Pt basis as a representative binary alloy containing Pt. Furthermore, metallic compositions are disclosed that possess substantial resistance to corrosive acids.

  13. Results of the Proficiency Test, PT1 and PT2, 2012

    Vendramin, Niccolò; Nicolajsen, Nicole; Christophersen, Maj-Britt

    A comparative test of diagnostic procedures was provided by the European Union Reference Laboratory (EURL) for Fish Diseases. The test was divided into proficiency test 1 (PT1) and proficiency test 2 (PT2). The number of National Reference Laboratories (NRLs) participating in PT1 and PT2 was 43. ....... The tests were sent from the EURL in the beginning of September 2012. Both PT1 and PT2 are accredited by DANAK under registration number 515 for proficiency testing according to the quality assurance standard DS/EN ISO/IEC 17043....

  14. Pt Skin Versus Pt Skeleton Structures of Pt3Sc as Electrocatalysts for Oxygen Reduction

    Johansson, Tobias Peter; Ulrikkeholm, Elisabeth Therese; Hernandez-Fernandez, Patricia

    2014-01-01

    . The development of new materials for this reaction is essential in order to increase the overall effeciency of the fuel cell. Herein, we study the effect of ultra high vacuum annealing on the structure and activity of polycrystalline Pt3Sc. Upon annealing in ultra high vacuum a Pt overlayer is formed......, relative to Pt(111), consistent with the CO adsorption energies calculated using density functional theory calculations. Exposing the annealed Pt3Sc sample to 200 mbar O2 at room temperature results in similar to 14 % Sc oxide as measured by X-ray photoelectron spectroscopy. Electrochemical testing...

  15. Exchange coupled CoPt/FePtC media for heat assisted magnetic recording

    Dutta, Tanmay; Piramanayagam, S. N.; Ru, Tan Hui; Saifullah, M. S. M.; Bhatia, C. S.; Yang, Hyunsoo

    2018-04-01

    L10 FePtC granular media are being studied as potential future magnetic recording media and are set to be used in conjunction with heat assisted magnetic recording (HAMR) to enable recording at write fields within the range of current day recording heads. Media structures based on a FePtC storage layer and a capping layer can alleviate the switching field distribution (SFD) requirements of HAMR and reduce the noise originating from the writing process. However, the current designs suffer from SFD issues due to high temperature writing. To overcome this problem, we study a CoPt/FePtC exchange coupled composite structure, where FePtC serves as the storage layer and CoPt (with higher Curie temperature, Tc) as the capping layer. CoPt remains ferromagnetic at near Tc of FePtC. Consequently, the counter exchange energy from CoPt would reduce the noise resulting from the adjacent grain interactions during the writing process. CoPt/FePtC bilayer samples with different thicknesses of CoPt were investigated. Our studies found that CoPt forms a continuous layer at a thickness of 6 nm and leads to considerable reduction in the saturation field and its distribution.

  16. Remarks on the PT-pseudo-norm in PT-symmetric quantum mechanics

    Duc Tai Trinh [Department of Mathematics, Teacher Training College of Dalat, 29 Yersin, Dalat (Viet Nam)]|[Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, Trieste 34014 (Italy)

    2005-04-22

    This paper presents an underlying analytical relationship between the PT-pseudo-norm associated with the PT-symmetric Hamiltonian H = p{sup 2} + V(q) and the Stokes multiplier of the differential equation corresponding to this Hamiltonian. We show that the sign alternation of the PT-pseudo-norm, which has been observed as a generic feature of the PT-inner product, is essentially controlled by the derivative of a Stokes multiplier with respect to the eigenparameter.

  17. Hydrogenation of Phenol over Pt/CNTs: The Effects of Pt Loading and Reaction Solvents

    Feng Li; Bo Cao; Wenxi Zhu; Hua Song; Keliang Wang; Cuiqin Li

    2017-01-01

    Carbon nanotubes (CNTs)-supported Pt nanoparticles were prepared with selective deposition of Pt nanoparticles inside and outside CNTs (Pt–in/CNTs and Pt–out/CNTs). The effects of Pt loading and reaction solvents on phenol hydrogenation were investigated. The Pt nanoparticles in Pt–in/CNTs versus Pt–out/CNTs are smaller and better dispersed. The catalytic activity and reuse stability toward phenol hydrogenation both improved markedly. The dichloromethane–water mixture as the reaction solvent,...

  18. Electron transport in a Pt-CO-Pt nanocontact: Density functional theory calculations

    Strange, Mikkel; Thygesen, Kristian Sommer; Jacobsen, Karsten Wedel

    2006-01-01

    We have performed first-principles calculations for the mechanic and electric properties of pure Pt nanocontacts and a Pt contact with a single CO molecule adsorbed. For the pure Pt contacts we see a clear difference between point contacts and short chains in good agreement with experiments. We...

  19. Residual gas analysis

    Berecz, I.

    1982-01-01

    Determination of the residual gas composition in vacuum systems by a special mass spectrometric method was presented. The quadrupole mass spectrometer (QMS) and its application in thin film technology was discussed. Results, partial pressure versus time curves as well as the line spectra of the residual gases in case of the vaporization of a Ti-Pd-Au alloy were demonstrated together with the possible construction schemes of QMS residual gas analysers. (Sz.J.)

  20. Tuning magnetic properties of non-collinear magnetization configuration in Pt/[Pt/Co]{sub 6}/Pt/Co/Pt multilayer structure

    Kalaycı, Taner, E-mail: taner.kalayci@marmara.edu.tr [Department of Physics, Marmara University, 34722, Kadıköy, Istanbul (Turkey); Deger, Caner [Department of Physics, Marmara University, 34722, Kadıköy, Istanbul (Turkey); Akbulut, Salih [Department of Physics, Gebze Technical University, 41400, Gebze, Kocaeli (Turkey); Yildiz, Fikret, E-mail: fyildiz@gtu.edu.tr [Department of Physics, Gebze Technical University, 41400, Gebze, Kocaeli (Turkey)

    2017-08-15

    Highlights: • Effects of Pt spacer and reference layers thickness are investigated by MOKE and FMR. • Controlling of non-collinear states in multilayered thin film systems is studied. • Micromagnetic approach is used for modeling of magnetic multilayered structure. • Magnetic parameters are determined by a simulation based on metropolis algorithm. - Abstract: In this study, effects of Pt spacer and Co reference layers thickness in [Co/Pt]{sub 6}/Pt/Co multilayer have been revealed to tailor magnetization directions in non-collinear configuration. Magneto-optic Kerr effect and ferromagnetic resonance techniques were employed to investigate magnetic properties. Bilinear coupling between [Co/Pt]{sub 6} and Co layers and anisotropy constants were determined by a micromagnetic simulation based on metropolis algorithm. 3 nm spacer causes ferromagnetic coupling while the samples have 4 and 5 nm spacer are coupled anti-ferromagneticaly. Also, tuning magnetic anisotropy of [Co/Pt]{sub 6} layer was accomplished by Co reference layer. It is revealed that controlling of non-collinear states in such systems is possible by variation of thickness of spacer and reference layers and [Co/Pt]{sub 6}/t{sub Pt}/t{sub Co} trilayer system can be used in multilayered magnetic systems.

  1. Measurement of residual solvents in a drug substance by a purge-and-trap method.

    Lakatos, Miklós

    2008-08-05

    The purge-and-trap (P&T) gas extraction method combined with gas chromatography was studied for its suitability for quantitative residual solvents determination in a water-soluble active pharmaceutical ingredient (API). Some analytical method performance characteristics were investigated, namely, the repeatability, the accuracy and the detection limit of determination. The results show that the P&T technique is--as expected--more sensitive than the static headspace, thus it can be used for the determination of residual solvents pertaining to the ICH Class 1 group. It was found that it could be an alternative sample preparation method besides the static headspace (HS) method.

  2. Nuclear structure of 194Pt

    Cleveland, W.E.; Zganjar, E.F.

    1976-01-01

    The decay of 194 Ir has been thoroughly studied resulting in the construction of a decay scheme consisting of 26 excited states and 69 transitions. Nine new levels and 29 new transitions were added to the previously known scheme. Of these, levels at 1,893.6 and 2,053.0 keV as well as 9 γ-ray transitions are new to the 194 Pt level scheme. Precise γ-ray energy and intensity measurements as well as quantitative coincidence measurements were performed, and the internal conversion spectrum was investigated with a Si(Li) detector. Directional correlation measurements were performed for selected cascades with the major result being the unique assignment of 0 + to the new level at 1,893.6 keV. The structure was interpreted within the framework of the PPQ model as well as the effective-core picture including nuclear triaxiality. (orig.) [de

  3. Nonlinear PT-symmetric plaquettes

    Li Kai; Kevrekidis, P G; Malomed, Boris A; Günther, Uwe

    2012-01-01

    We introduce four basic two-dimensional (2D) plaquette configurations with onsite cubic nonlinearities, which may be used as building blocks for 2D PT-symmetric lattices. For each configuration, we develop a dynamical model and examine its PTsymmetry. The corresponding nonlinear modes are analyzed starting from the Hamiltonian limit, with zero value of the gain–loss coefficient, γ. Once the relevant waveforms have been identified (chiefly, in an analytical form), their stability is examined by means of linearization in the vicinity of stationary points. This reveals diverse and, occasionally, fairly complex bifurcations. The evolution of unstable modes is explored by means of direct simulations. In particular, stable localized modes are found in these systems, although the majority of identified solutions are unstable. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)

  4. Adsorption studies on Pt(111)

    Hopster, H.

    1977-06-01

    The adsorption of O 2 , CO, and C 2 H 2 as well as the CO oxidation on Pt(111) were studied by high-resolution electron spectroscopy. Using a platinum monocrystal sample with a contonuous stage density, the adhesion coefficient for O 2 and the reaction probability for CO were determined as a function of stage density and oxygen cover by measuring the oxygen cover and its time behaviour. The study of vibrations of adsorbed CO showed that CO is bound in linear form on two different adsorption sites. The adsorption of acetylene was studied at 140 K and 300 K. The frequencies of the C-H stretching and flexural vibrations as well as the C-C-H bonding angle were determined. (orig./GSC) [de

  5. Surface coverage of Pt atoms on PtCo nanoparticles and catalytic kinetics for oxygen reduction

    Jiang Rongzhong, E-mail: rongzhong.jiang@us.army.mi [Sensors and Electron Devices Directorate, U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783-1197 (United States); Rong, Charles; Chu, Deryn [Sensors and Electron Devices Directorate, U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, MD 20783-1197 (United States)

    2011-02-01

    The surface coverage of Pt atoms on PtCo nanoparticles and its effect on catalytic kinetics for oxygen reduction were investigated. The PtCo nanoparticles with different surface coverage of Pt atoms were synthesized with various methods, including normal chemical method, microemulsion synthesis, and ultrasound-assisted microemulsion. A model of Pt atoms filling into a spherical nanoparticle was proposed to explain the relationship of surface metal atoms and nanoparticle size. The catalytic activity of the PtCo nano-particles is highly dependent on the synthetic methods, even if they have the same chemical composition. The PtCo nano-particles synthesized with ultrasound-assisted microemulsion showed the highest activity, which is attributed to an increase of active surface coverage of Pt atoms on the metal nanoparticles. The rate of oxygen reduction at 0.5 V (vs. SCE) catalyzed by the PtCo synthesized with ultrasound-assisted micro-emulsion was about four times higher than that of the PtCo synthesized with normal chemical method. As demonstrated with rotating-ring disk electrode measurement, the PtCo nano-particles can catalyze oxygen 4-electron reduction to water without intermediate H{sub 2}O{sub 2} detected.

  6. Ethanol electrooxidation on Pt-Sn and Pt-Sn-W bulk alloys

    Anjos, D.M. dos; Hahn, F.; Leger, J.M.; Kokoh, K.B. [Universite de Poitiers, Poitiers Cedex (France). Centre National de la Recherche Scientifique (CNRS). Equipe Electrocatalyse; Tremiliosi-Filho, G. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica

    2008-07-01

    Ethanol oxidation has been studied on Pt-Sn and Pt-Sn-W electrodes prepared in an arc-melting furnace. Different electrochemical techniques like cyclic voltammetry and chronoamperometry were used to evaluate the catalytic activity of these materials. The electro-oxidation process was also investigated by in situ infrared reflectance spectroscopy in order to determine adsorbed intermediates and reaction products. Experimental results indicated that Pt-Sn and Pt-Sn-W alloys are able to oxidize ethanol mainly to acetaldehyde and acetic acid. Adsorbed CO was also detected, demonstrating the viability of splitting the C-C bond in the ethanol molecule during the oxidation process. The adsorbed CO was further oxidized to CO{sub 2}.This reaction product was clearly detected by SNIFTIRS. Pt-Sn-W catalyst showed a better electrochemical performance than Pt-Sn that, in it turn, is better than Pt-alone. (author)

  7. Thermodynamic modeling of the Pt-Zr system

    Gao Yongliang; Guo Cuiping; Li Changrong; Du Zhenmin

    2010-01-01

    By means of the CALPHAD (CALculation of PHAse Diagram) technique, the Pt-Zr system was critically assessed. The solution phases (liquid, bcc, fcc and hcp) are described with the substitutional model. The intermetallic compounds Pt 4 Zr, Pt 4 Zr 3 , αPtZr and Pt 3 Zr 5 are treated as the formula (Pt,Zr) m (Pt,Zr) n by a two-sublattice model with the elements Pt and Zr on the first and the second sublattices, respectively. A two-sublattice model (Pt,Zr) 0.5 (Pt,Zr) 0.5 is applied to describe the compound βPtZr with CsCl-type structure (B2) in order to cope with the order-disorder transition between bcc solution (A2) and βPtZr (B2). Another two-sublattice model (Pt,Zr) 0.75 (Pt,Zr) 0.25 with Ni 3 Ti-type structure (D0 24 ) is applied to describe the compound Pt 3 Zr in order to cope with the order-disorder transition between hexagonal close-packed (A3) and Pt 3 Zr (D0 24 ). The compound Pt 10 Zr 7 is treated as a stoichiometric compound. A set of self-consistent thermodynamic parameters of the Pt-Zr system was obtained. (orig.)

  8. Low-temperature phase diagram of YbBiPt

    Movshovich, R.; Lacerda, A.; Canfield, P.C.; Thompson, J.D.; Fisk, Z.

    1994-01-01

    Resistivity measurements are reported on the cubic heavy-fermion compound YbBiPt at ambient and hydrostatic pressures to ∼19 kbar and in magnetic fields to 1 T. The phase transition at T c =0.4 K is identified by a sharp rise in resistivity. That feature is used to build low-temperature H-T and P-T phase diagrams. The phase boundary in the H-T plane follows the weak-coupling BCS expression remarkably well from T c to T c /4, while small hydrostatic pressure of ∼1 kbar suppresses the low-temperature phase entirely. These effects of hydrostatic pressure and magnetic field on the phase transition are consistent with an spin-density-wave (SDW) formation in a very heavy electron band at T=0.4 K. Outside of the SDW phase at low temperature, hydrostatic pressure increases the T 2 coefficient of resistivity, signaling an increase in heavy-fermion correlations with hydrostatic pressure. The residual resistivity decreases with pressure, contrary to trends in other Yb heavy-fermion compounds

  9. Shape transition in Os and Pt isotopes

    Ansari, A.

    1985-07-01

    Ground state structure of A=186 to 196 Os-Pt transitional region is investigated through a self-consistent Hartree-Fock-Bogolyubov calculation employing a pairing-plus-quadrupole-plus-hexadecapole model interaction Hamiltonian. Influence of the hexadecapole degrees of freedom on the triaxiality is especially examined. A gradual prolate to oblate shape transition is found in Pt isotopes but such a change is almost abrupt in Os at A approx. = 194. This difference in behaviour of the Os and Pt isotopes is obtained only if all the hexadecapole degrees of freedom, instead of merely an axial Y 40 component, are treated fully self-consistently. (author)

  10. Handling of Solid Residues

    Medina Bermudez, Clara Ines

    1999-01-01

    The topic of solid residues is specifically of great interest and concern for the authorities, institutions and community that identify in them a true threat against the human health and the atmosphere in the related with the aesthetic deterioration of the urban centers and of the natural landscape; in the proliferation of vectorial transmitters of illnesses and the effect on the biodiversity. Inside the wide spectrum of topics that they keep relationship with the environmental protection, the inadequate handling of solid residues and residues dangerous squatter an important line in the definition of political and practical environmentally sustainable. The industrial development and the population's growth have originated a continuous increase in the production of solid residues; of equal it forms, their composition day after day is more heterogeneous. The base for the good handling includes the appropriate intervention of the different stages of an integral administration of residues, which include the separation in the source, the gathering, the handling, the use, treatment, final disposition and the institutional organization of the administration. The topic of the dangerous residues generates more expectation. These residues understand from those of pathogen type that are generated in the establishments of health that of hospital attention, until those of combustible, inflammable type, explosive, radio-active, volatile, corrosive, reagent or toxic, associated to numerous industrial processes, common in our countries in development

  11. Pengukuran Kepuasan Kerja Karyawan APLP & A PT Semen Padang (PT X

    Shelly Nolandari

    2016-04-01

    Full Text Available Thoughts on employee satisfaction arise because the company believes its employees have a high level of satisfaction will result in a better level of productivity, work more accurate, the fewer the number of absences and higher loyalty than employees with low satisfaction levels.Company's with good productivity will grow and increase revenue. PT Semen Padang has several subsidiaries and affiliates like PT X. PT X will measure employee satisfaction with the company's expectations are always making changes that sustainable about employee satisfaction because companies believe that employee satisfaction level of its high yield levels better productivity, work more accurate, the number of absences are fewer and loyalty higher than employees with low satisfaction levels. Companies with good productivity will experience growth as indicated by the increase in revenue, in line with the increase in the welfare of the employees. PT Semen Padang has several subsidiaries and affiliates PT X. PT Xwill measure employee satisfaction with the Company's expectations.

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

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

    2011-02-15

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

  13. Golden Gate and Pt. Reyes Acoustic Detections

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detections of acoustic tagged fish from two general locations: Golden Gate (east and west line) and Pt. Reyes. Several Vemco 69khz acoustic...

  14. Electrochemical stability of subnanometer Pt clusters

    Quinson, Jonathan; Röefzaad, Melanie; Deiana, Davide

    2018-01-01

    In the present work, the degradation of size-selected Pt nanoclusters is studied under electrochemical conditions. This model catalyst mimics carbon supported Pt nanoclusters and nanoparticles typically employed in proton exchange membrane fuel cells (PEMFCs). Insight into the early stage...... of degradation is given by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and confirmed by transmission electron microscopy (TEM). In contrast to common assumptions, it is demonstrated that even extremely small Pt clusters exhibit a remarkable stability under electrochemical...... - is observed. In light of the findings reported, developing highly-dispersed subnanometer Pt clusters as catalyst for PEMFCs is a realistic approach provided the operation conditions are suitably adjusted. Furthermore, mitigation strategies to improve the stability of few-atoms catalyst under electrochemical...

  15. 195Pt and 119Sn Knight shifts of U3Pt3Sn4

    Kojima, K.; Takabatake, T.; Harada, A.; Hihara, T.

    1995-01-01

    The 195 Pt and 119 Sn Knight shifts in U 3 Pt 3 Sn 4 have been measured in the temperature range 4.2-298K. They exhibit Curie-Weiss like behaviors above about 50K and remain constant below about 10K. This suggests that the deviation of χ(T) from the modified Curie-Weiss law is an intrinsic property of U 3 Pt 3 Sn 4 . ((orig.))

  16. Dependence of Magnetic Properties of Co/Pt Multilayers on Deposition Temperature of Pt Buffer Layers

    Shiomi, Shigeru; Nishimura, Tomotaka; Kobayashi, Tadashi; Masuda, Morio

    1993-04-01

    A 15-nm-thick Pt buffer layer was deposited on a glass slide at temperature Ts(Ptbuf) ranging from 30 to 300°C by e-gun evaporation. Following the cooling in vacuum to ambient temperature, Co and Pt layers have been alternately deposited on it. Very large perpendicular anisotropy and coercivity have been obtained at Ts(Ptbuf) higher than 200°C. The (111) preferred orientation of the Co/Pt multilayer as well as the Pt buffer layer became more pronounced with elevating Ts(Ptbuf), to which the enhancement of perpendicular anisotropy with elevating Ts(Ptbuf) might be ascribable.

  17. Measurement of benzenethiol adsorption to nanostructured Pt, Pd, and PtPd films using Raman spectroelectrochemistry.

    Pomfret, Michael B; Pietron, Jeremy J; Owrutsky, Jeffrey C

    2010-05-04

    Raman spectroscopy and electrochemical methods were used to study the behavior of the model adsorbate benzenethiol (BT) on nanostructured Pt, Pd, and PtPd electrodes as a function of applied potential. Benzenethiol adsorbs out of ethanolic solutions as the corresponding thiolate, and voltammetric stripping data reveal that BT is oxidatively removed from all of the nanostructured metals upon repeated oxidative and reductive cycling. Oxidative stripping potentials for BT increase in the order Pt oxidizing potentials via cleavage of the Pt-S bond. In contrast, on nanoscale Pd and PtPd, BT is irreversibly lost due to cleavage of BT C-S bonds at oxidizing potentials, which leaves adsorbed sulfur oxides on Pd and PtPd films and effects the desulfurization of BT. While Pd and PtPd films are less sulfur-resistant than Pt films, palladium oxides, which form at higher potentials than Pt oxides, oxidatively desulfurize BT. In situ spectroelectrochemical Raman spectroscopy provides real-time, chemically specific information that complements the cyclic voltammetric data. The combination of these techniques affords a powerful and convenient method for guiding the development of sulfur-tolerant PEMFC catalysts.

  18. Preparation of PtSn/C, PtRu/C, PtRh/C, PtRuRh/C and PtSnRh/C electrocatalysts using an alcohol-reduction process for methanol and ethanol oxidation

    Dias, Ricardo Rodrigues

    2009-01-01

    In this work, Pt/C, PtRh (90:10), PtRh/C (50:50), PtSn/C (50:50), PtRu (50:50)/C, PtRuRh/C (50:40:10) and PtSnRh/C (50:40:10) were prepared by an alcohol-reduction process with metal loading of 20 wt.% using H 2 PtCl 6 .6H 2 O (Aldrich), SnCl 2 .2H 2 O (Aldrich),and RhCl 2 .XH 2 O (Aldrich) as metals sources and Vulcan XC72 as support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry (CV). The electro-oxidation of ethanol was studied by CV, chronoamperomety at room temperature in acid medium and tests at 100 deg C on a single cell of a direct methanol or ethanol fuel cell. The EDX analysis showed that the metal atomic ratios of the obtained electrocatalysts were similar to the nominal atomic ratios used in the preparation. The diffractograms of electrocatalysts prepared showed four peaks at approximately 2θ = 40 0 , 47 0 , 67 0 and 82 0 , which are associated with the (111), (200), (220) and (311) planes, respectively, of a face cubic-centered (fcc) structure characteristic of platinum and platinum alloys. The average crystallite sizes using the Scherrer equation and the calculated values were in the range of 2–3 nm. For PtSn/C and PtSnRh/C two additional peaks were observed at 2θ = 34 0 and 52 0 that were identified as a SnO 2 phase. PtSn/C (50:50) and PtSnRh/C (50:40:10) electrocatalyst showed the best performance for ethanol oxidation at room temperature. For methanol oxidation at room temperature PtRu/C, PtSn/C and PtRuRh/C electrocatalysts showed the best performance. Tests at 100 deg C on a single cell of a direct ethanol fuel cell PtSnRh/C showed the best performance, for methanol oxidation PtRuRh/C showed the best performance. (author)

  19. Synthesis and electrochemical study of Pt-based nanoporous materials

    Wang Jingpeng; Holt-Hindle, Peter; MacDonald, Duncan; Thomas, Dan F.; Chen Aicheng

    2008-01-01

    In the present work, a variety of Pt-based bimetallic nanostructured materials including nanoporous Pt, Pt-Ru, Pt-Ir, Pt-Pd and Pt-Pb networks have been directly grown on titanium substrates via a facile hydrothermal method. The as-fabricated electrodes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical methods. The active surface areas of these nanoporous Pt-based alloy catalysts are increased by over 68 (Pt-Pd), 69 (Pt-Ru) and 113 (Pt-Ir) fold compared to a polycrystalline Pt electrode. All these synthesized nanoporous electrodes exhibit superb electrocatalytic performance towards electrochemical oxidation of methanol and formic acid. Among the five nanoporous Pt-based electrodes, the Pt-Ir shows the highest peak current density at +0.50 V, with 68 times of enhancement compared to the polycrystalline Pt for methanol oxidation, and with 86 times of enhancement in formic acid oxidation; whereas the catalytic activity of the nanoporous Pt-Pb electrode outperforms the other materials in formic acid oxidation at the low potential regions, delivering an enhanced current density by 280-fold compared to the polycrystalline Pt at +0.15 V. The new approach described in this study is suitable for synthesizing a wide range of bi-metallic and tri-metallic nanoporous materials, desirable for electrochemical sensor design and potential application in fuel cells

  20. Synthesis and electrochemical study of Pt-based nanoporous materials

    Wang Jingpeng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Holt-Hindle, Peter; MacDonald, Duncan [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Thomas, Dan F. [Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Chen Aicheng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada)], E-mail: aicheng.chen@lakeheadu.ca

    2008-10-01

    In the present work, a variety of Pt-based bimetallic nanostructured materials including nanoporous Pt, Pt-Ru, Pt-Ir, Pt-Pd and Pt-Pb networks have been directly grown on titanium substrates via a facile hydrothermal method. The as-fabricated electrodes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical methods. The active surface areas of these nanoporous Pt-based alloy catalysts are increased by over 68 (Pt-Pd), 69 (Pt-Ru) and 113 (Pt-Ir) fold compared to a polycrystalline Pt electrode. All these synthesized nanoporous electrodes exhibit superb electrocatalytic performance towards electrochemical oxidation of methanol and formic acid. Among the five nanoporous Pt-based electrodes, the Pt-Ir shows the highest peak current density at +0.50 V, with 68 times of enhancement compared to the polycrystalline Pt for methanol oxidation, and with 86 times of enhancement in formic acid oxidation; whereas the catalytic activity of the nanoporous Pt-Pb electrode outperforms the other materials in formic acid oxidation at the low potential regions, delivering an enhanced current density by 280-fold compared to the polycrystalline Pt at +0.15 V. The new approach described in this study is suitable for synthesizing a wide range of bi-metallic and tri-metallic nanoporous materials, desirable for electrochemical sensor design and potential application in fuel cells.0.

  1. Synthesis and electrochemical study of Pt-based nanoporous materials

    Wang, Jingpeng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Holt-Hindle, Peter; MacDonald, Duncan; Chen, Aicheng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Thomas, Dan F. [Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)

    2008-10-01

    In the present work, a variety of Pt-based bimetallic nanostructured materials including nanoporous Pt, Pt-Ru, Pt-Ir, Pt-Pd and Pt-Pb networks have been directly grown on titanium substrates via a facile hydrothermal method. The as-fabricated electrodes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical methods. The active surface areas of these nanoporous Pt-based alloy catalysts are increased by over 68 (Pt-Pd), 69 (Pt-Ru) and 113 (Pt-Ir) fold compared to a polycrystalline Pt electrode. All these synthesized nanoporous electrodes exhibit superb electrocatalytic performance towards electrochemical oxidation of methanol and formic acid. Among the five nanoporous Pt-based electrodes, the Pt-Ir shows the highest peak current density at +0.50 V, with 68 times of enhancement compared to the polycrystalline Pt for methanol oxidation, and with 86 times of enhancement in formic acid oxidation; whereas the catalytic activity of the nanoporous Pt-Pb electrode outperforms the other materials in formic acid oxidation at the low potential regions, delivering an enhanced current density by 280-fold compared to the polycrystalline Pt at +0.15 V. The new approach described in this study is suitable for synthesizing a wide range of bi-metallic and tri-metallic nanoporous materials, desirable for electrochemical sensor design and potential application in fuel cells. (author)

  2. Characterization of Hospital Residuals

    Blanco Meza, A.; Bonilla Jimenez, S.

    1997-01-01

    The main objective of this investigation is the characterization of the solid residuals. A description of the handling of the liquid and gassy waste generated in hospitals is also given, identifying the source where they originate. To achieve the proposed objective the work was divided in three stages: The first one was the planning and the coordination with each hospital center, in this way, to determine the schedule of gathering of the waste can be possible. In the second stage a fieldwork was made; it consisted in gathering the quantitative and qualitative information of the general state of the handling of residuals. In the third and last stage, the information previously obtained was organized to express the results as the production rate per day by bed, generation of solid residuals for sampled services, type of solid residuals and density of the same ones. With the obtained results, approaches are settled down to either determine design parameters for final disposition whether for incineration, trituration, sanitary filler or recycling of some materials, and storage politics of the solid residuals that allow to determine the gathering frequency. The study concludes that it is necessary to improve the conditions of the residuals handling in some aspects, to provide the cleaning personnel of the equipment for gathering disposition and of security, minimum to carry out this work efficiently, and to maintain a control of all the dangerous waste, like sharp or polluted materials. In this way, an appreciable reduction is guaranteed in the impact on the atmosphere. (Author) [es

  3. 40 CFR Appendix Viii to Part 266 - Organic Compounds for Which Residues Must Be Analyzed

    2010-07-01

    ... AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES AND SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES Pt. 266, App. VIII Appendix VIII to Part 266... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Organic Compounds for Which Residues...

  4. Resistive switching in Pt/TiO{sub 2}/Pt

    Jeong, Doo Seok

    2008-08-15

    Recently, the resistive switching behavior in TiO{sub 2} has drawn attention due to its application to resistive random access memory (RRAM) devices. TiO{sub 2} shows characteristic non-volatile resistive switching behavior, i.e. reversible switching between a high resistance state (HRS) and a low resistance state (LRS). Both unipolar resistive switching (URS) and bipolar resistive switching (BRS) are found to be observed in TiO{sub 2} depending on the compliance current for the electroforming. In this thesis the characteristic current-voltage (I-V) hysteresis in three different states of TiO{sub 2}, pristine, URS-activated, and BRS-activated states, was investigated and understood in terms of the migration of oxygen vacancies in TiO{sub 2}. The I-V hysteresis of pristine TiO{sub 2} was found to show volatile behavior. That is, the temporary variation of the resistance took place depending on the applied voltage. However, the I-V hysteresis of URS- and BRS-activated states showed non-volatile resistive switching behavior. Some evidences proving the evolution of oxygen gas during electroforming were obtained from time-of-flight secondary ion mass spectroscopy analysis and the variation of the morphology of switching cells induced by the electroforming. On the assumption that a large number of oxygen vacancies are introduced by the electroforming process, the I-V behavior in electroformed switching cells was simulated with varying the distribution of oxygen vacancies in electroformed TiO{sub x} (x Pt/TiO{sub x} interface. The oxygen-related reactions given as a function of the applied voltage affect the distribution of oxygen vacancies in TiO{sub x}, consequently, the Schottky barrier height at the cathode/TiO{sub x} interface is influenced by the oxygen vacancy distribution. Therefore, the BRS behavior including the

  5. Synthesis of Supported NiPt Bimetallic Nanoparticles, Methods for Controlling the Surface Coverage of Ni Nanoparticles With Pt, Methods Of Making NiPt Multilayer Core-Shell Structures and Application of the Supported Catalysts for CO2 Reforming

    Li, Lidong; Anjum, Dalaver H.; Zhou, Lu; Laveille, Paco; Basset, Jean-Marie

    2015-01-01

    Embodiments of the present disclosure provide for supported Ni/Pt bimetallic nanoparticles, compositions including supported NiPt nanoparticles, methods of making supported NiPt nanoparticles, methods of using supported NiPt nanoparticles

  6. Synthesis of Supported NiPt Bimetallic Nanoparticles, Methods for Controlling the Surface Coverage of Ni Nanoparticles With Pt, Methods Of Making NiPt Multilayer Core-Shell Structures and Application of the Supported Catalysts for CO2 Reforming

    Li, Lidong

    2015-06-25

    Embodiments of the present disclosure provide for supported Ni/Pt bimetallic nanoparticles, compositions including supported NiPt nanoparticles, methods of making supported NiPt nanoparticles, methods of using supported NiPt nanoparticles, and the like.

  7. Properties of RF-Sputtered PZT Thin Films with Ti/Pt Electrodes

    Cui Yan

    2014-01-01

    Full Text Available Effect of annealing temperature and thin film thickness on properties of Pb(Zr0.53Ti0.47O3 (PZT thin film deposited via radiofrequency magnetron sputtering technique onto Pt/Ti/SiO2/Si substrate was investigated. Average grain sizes of the PZT thin film were measured by atomic force microscope; their preferred orientation was studied through X-ray diffraction analysis. Average residual stress in the thin film was estimated according to the optimized Stoney formula, and impedance spectroscopy characterization was performed via an intelligent LCR measuring instrument. Average grain sizes of PZT thin films were 60 nm~90 nm and their average roughness was less than 2 nm. According to X-ray diffraction analysis, 600°C is the optimal annealing temperature to obtain the PZT thin film with better crystallization. Average residual stress showed that thermal mismatch was the decisive factor of residual stress in Pt/Ti/SiO2/Si substrate; the residual stress in PZT thin film decreased as their thickness increased and increased with annealing temperature. The dielectric constant and loss angle tangent were extremely increased with the thickness of PZT thin films. The capacitance of the device can be adjusted according to the thickness of PZT thin films.

  8. Phage Types and Genotypes of Shiga Toxin-Producing Escherichia coli O157:H7 Isolates from Humans and Animals in Spain: Identification and Characterization of Two Predominating Phage Types (PT2 and PT8)

    Mora, Azucena; Blanco, Miguel; Blanco, Jesús E.; Alonso, M. Pilar; Dhabi, Ghizlane; Thomson-Carter, Fiona; Usera, Miguel A.; Bartolomé, Rosa; Prats, Guillermo; Blanco, Jorge

    2004-01-01

    Phage typing and DNA macrorestriction fragment analysis by pulsed-field electrophoresis (PFGE) were used for the epidemiological subtyping of a collection of Shiga toxin-producing Escherichia coli (STEC) O157:H7 strains isolated in Spain between 1980 and 1999. Phage typing distinguished a total of 18 phage types among 171 strains isolated from different sources (67 humans, 82 bovines, 12 ovines, and 10 beef products). However, five phage types, phage type 2 (PT2; 42 strains), PT8 (33 strains), PT14 (14 strains), PT21/28 (11 strains), and PT54 (16 strains), accounted for 68% of the study isolates. PT2 and PT8 were the most frequently found among strains from both humans (51%) and bovines (46%). Interestingly, we detected a significant association between PT2 and PT14 and the presence of acute pathologies. A group of 108 of the 171 strains were analyzed by PFGE, and 53 distinct XbaI macrorestriction patterns were identified, with 38 strains exhibiting unique PFGE patterns. In contrast, phage typing identified 15 different phage types. A total of 66 phage type-PFGE subtype combinations were identified among the 108 strains. PFGE subtyping differentiated between unrelated strains that exhibited the same phage type. The most common phage type-PFGE pattern combinations were PT2-PFGE type 1 (1 human and 11 bovine strains), PT8-PFGE type 8 (2 human, 6 bovine, and 1 beef product strains), PT2-PFGE subtype 4A (1 human, 3 bovine, and 1 beef product strains). Nine (29%) of 31 human strains showed phage type-PFGE pattern combinations that were detected among the bovine strains included in this study, and 26 (38%) of 68 bovine strains produced phage type-PFGE pattern combinations observed among human strains included in this study, confirming that cattle are a major reservoir of strains pathogenic for humans. PT2 and PT8 strains formed two groups which differed from each other in their motilities, stx genotypes, PFGE patterns, and the severity of the illnesses that they caused

  9. 40 CFR 180.443 - Myclobutanil; tolerances for residues.

    2010-07-01

    ... Horse, meat byproducts, except liver 0.2 Leafy greens, subgroup 4A, except spinach 9.0 Mango 3.0 Mayhaw... established for residues of the fungicide myclobutanil in connection with use of the pesticide under section...

  10. Microwave sinthesys and characterization of Pt and Pt-Rh-Sn electrocatalysts for ethanol oxidation

    Jovanović Vladislava M.

    2011-01-01

    Full Text Available Carbon supported Pt and Pt-Rh-Sn catalysts were synthesized by microwave-polyol method in ethylene glycol solution and investigated for the ethanol electro-oxidation reaction. The catalysts were characterized in terms of structure, morphology and composition by employing XRD, STM and EDX techniques. STM analysis indicated rather uniform particles and particle size of below 2 nm for both catalysts. XRD analysis of the Pt/C catalyst revealed two phases, one with the main characteristic peaks of face centered cubic crystal structure (fcc of platinum and another related to graphite like structure of carbon support Vulcan XC-72R. However, in XRD pattern of the Pt-Rh-Sn/C catalyst diffraction peaks for Pt, Rh or Sn cannot be resolved, indicating an extremely low crystallinity. The small particle sizes and homogeneous size distributions of both catalysts should be attributed to the advantages of microwave assisted modified polyol process in ethylene glycol solution. Pt-Rh- Sn/C catalyst is highly active for the ethanol oxidation with the onset potential shifted for more than 150 mV to negative values and with currents nearly 5 times higher in comparison to Pt/C catalyst. The stability tests of the catalysts, as studied by the chronoamperometric experiments, reveal that the Pt-Rh-Sn/C catalyst is evidently less poisoned then Pt/C catalyst. The increased activity of Pt-Rh-Sn/C in comparison to Pt/C catalyst is most probably promoted by bifunctional mechanism and the electronic effect of alloyed metals.

  11. Pt skin coated hollow Ag-Pt bimetallic nanoparticles with high catalytic activity for oxygen reduction reaction

    Fu, Tao; Huang, Jianxing; Lai, Shaobo; Zhang, Size; Fang, Jun; Zhao, Jinbao

    2017-10-01

    The catalytic activity and stability of electrocatalyst is critical for the commercialization of fuel cells, and recent reports reveal the great potential of the hollow structures with Pt skin coat for developing high-powered electrocatalysts due to their highly efficient utilization of the Pt atoms. Here, we provide a novel strategy to prepare the Pt skin coated hollow Ag-Pt structure (Ag-Pt@Pt) of ∼8 nm size at room temperature. As loaded on the graphene, the Ag-Pt@Pt exhibits a remarkable mass activity of 0.864 A/mgPt (at 0.9 V, vs. reversible hydrogen electrode (RHE)) towards oxygen reduction reaction (ORR), which is 5.30 times of the commercial Pt/C catalyst, and the Ag-Pt@Pt also shows a better stability during the ORR catalytic process. The mechanism of this significant enhancement can be attributed to the higher Pt utilization and the unique Pt on Ag-Pt surface structure, which is confirmed by the density functional theory (DFT) calculations and other characterization methods. In conclusion, this original work offers a low-cost and environment-friendly method to prepare a high active electrocatalyst with cheaper price, and this work also discloses the correlation between surface structures and ORR catalytic activity for the hollow structures with Pt skin coat, which can be instructive for designing novel advanced electrocatalysts for fuel cells.

  12. Pt and PtRu catalyst bilayers increase efficiencies for ethanol oxidation in proton exchange membrane electrolysis and fuel cells

    Altarawneh, Rakan M.; Pickup, Peter G.

    2017-10-01

    Polarization curves, product distributions, and reaction stoichiometries have been measured for the oxidation of ethanol at anodes consisting of Pt and PtRu bilayers and a homogeneous mixture of the two catalysts. These anode structures all show synergies between the two catalysts that can be attributed to the oxidation of acetaldehyde produced at the PtRu catalyst by the Pt catalyst. The use of a PtRu layer over a Pt layer produces the strongest effect, with higher currents than a Pt on PtRu bilayer, mixed layer, or either catalyst alone, except for Pt at high potentials. Reaction stoichiometries (average number of electrons transferred per ethanol molecule) were closer to the values for Pt alone for both of the bilayer configurations but much lower for PtRu and mixed anodes. Although Pt alone would provide the highest overall fuel cell efficiency at low power densities, the PtRu on Pt bilayer would provide higher power densities without a significant loss of efficiency. The origin of the synergy between the Pt and PtRu catalysts was elucidated by separation of the total current into the individual components for generation of carbon dioxide and the acetaldehyde and acetic acid byproducts.

  13. Preparation of PtSn/C, PtRu/C, PtRh/C, PtRuRh/C and PtSnRh/C electrocatalysts using an alcohol-reduction process for methanol and ethanol oxidation; Preparacao e caracterizacao de eletrocatalisadores PtRu, PtSn, PtRh, PtRuRh e PtSnRh para oxidacao direta de alcoois em celulas a combustivel tipo PEM utilizando a metodologia da reducao por alcool

    Dias, Ricardo Rodrigues

    2009-07-01

    In this work, Pt/C, PtRh (90:10), PtRh/C (50:50), PtSn/C (50:50), PtRu (50:50)/C, PtRuRh/C (50:40:10) and PtSnRh/C (50:40:10) were prepared by an alcohol-reduction process with metal loading of 20 wt.% using H{sub 2}PtCl{sub 6}.6H{sub 2}O (Aldrich), SnCl{sub 2}.2H{sub 2}O (Aldrich),and RhCl{sub 2}.XH{sub 2}O (Aldrich) as metals sources and Vulcan XC72 as support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry (CV). The electro-oxidation of ethanol was studied by CV, chronoamperomety at room temperature in acid medium and tests at 100 deg C on a single cell of a direct methanol or ethanol fuel cell. The EDX analysis showed that the metal atomic ratios of the obtained electrocatalysts were similar to the nominal atomic ratios used in the preparation. The diffractograms of electrocatalysts prepared showed four peaks at approximately 2{theta} =40 deg, 47 deg, 67 deg and 82 deg, which are associated with the (111), (200), (220) and (311) planes, respectively, of a face cubic-centered (fcc) structure characteristic of platinum and platinum alloys. The average crystallite sizes using the Scherrer equation and the calculated values were in the range of 2-3 nm. For Pt Sn/C and PtSnRh/C two additional peaks were observed at 2 = 34 deg and 52 deg that were identified as a SnO{sub 2} phase. Pt Sn/C (50:50) and PtSnRh/C (50:40:10) electro catalyst showed the best performance for ethanol oxidation at room temperature. For methanol oxidation at room temperature Pt Ru/C, Pt Sn/C and PtRuRh/C electrocatalysts showed the best performance. Tests at 100 deg C on a single cell of a direct ethanol fuel cell PtSnRh/C showed the best performance, for methanol oxidation PtRuRh/C showed the best performance. (author)

  14. Preparation of PtSn/C, PtRu/C, PtRh/C, PtRuRh/C and PtSnRh/C electrocatalysts using an alcohol-reduction process for methanol and ethanol oxidation; Preparacao e caracterizacao de eletrocatalisadores PtRu, PtSn, PtRh, PtRuRh e PtSnRh para oxidacao direta de alcoois em celulas a combustivel tipo PEM utilizando a metodologia da reducao por alcool

    Dias, Ricardo Rodrigues

    2009-07-01

    In this work, Pt/C, PtRh (90:10), PtRh/C (50:50), PtSn/C (50:50), PtRu (50:50)/C, PtRuRh/C (50:40:10) and PtSnRh/C (50:40:10) were prepared by an alcohol-reduction process with metal loading of 20 wt.% using H{sub 2}PtCl{sub 6}.6H{sub 2}O (Aldrich), SnCl{sub 2}.2H{sub 2}O (Aldrich),and RhCl{sub 2}.XH{sub 2}O (Aldrich) as metals sources and Vulcan XC72 as support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry (CV). The electro-oxidation of ethanol was studied by CV, chronoamperomety at room temperature in acid medium and tests at 100 deg C on a single cell of a direct methanol or ethanol fuel cell. The EDX analysis showed that the metal atomic ratios of the obtained electrocatalysts were similar to the nominal atomic ratios used in the preparation. The diffractograms of electrocatalysts prepared showed four peaks at approximately 2θ = 40{sup 0}, 47{sup 0}, 67{sup 0} and 82{sup 0}, which are associated with the (111), (200), (220) and (311) planes, respectively, of a face cubic-centered (fcc) structure characteristic of platinum and platinum alloys. The average crystallite sizes using the Scherrer equation and the calculated values were in the range of 2–3 nm. For PtSn/C and PtSnRh/C two additional peaks were observed at 2θ = 34{sup 0} and 52{sup 0} that were identified as a SnO{sub 2} phase. PtSn/C (50:50) and PtSnRh/C (50:40:10) electrocatalyst showed the best performance for ethanol oxidation at room temperature. For methanol oxidation at room temperature PtRu/C, PtSn/C and PtRuRh/C electrocatalysts showed the best performance. Tests at 100 deg C on a single cell of a direct ethanol fuel cell PtSnRh/C showed the best performance, for methanol oxidation PtRuRh/C showed the best performance. (author)

  15. Management of NORM Residues

    2013-06-01

    The IAEA attaches great importance to the dissemination of information that can assist Member States in the development, implementation, maintenance and continuous improvement of systems, programmes and activities that support the nuclear fuel cycle and nuclear applications, and that address the legacy of past practices and accidents. However, radioactive residues are found not only in nuclear fuel cycle activities, but also in a range of other industrial activities, including: - Mining and milling of metalliferous and non-metallic ores; - Production of non-nuclear fuels, including coal, oil and gas; - Extraction and purification of water (e.g. in the generation of geothermal energy, as drinking and industrial process water; in paper and pulp manufacturing processes); - Production of industrial minerals, including phosphate, clay and building materials; - Use of radionuclides, such as thorium, for properties other than their radioactivity. Naturally occurring radioactive material (NORM) may lead to exposures at some stage of these processes and in the use or reuse of products, residues or wastes. Several IAEA publications address NORM issues with a special focus on some of the more relevant industrial operations. This publication attempts to provide guidance on managing residues arising from different NORM type industries, and on pertinent residue management strategies and technologies, to help Member States gain perspectives on the management of NORM residues

  16. Strongly bound excitons in monolayer PtS2 and PtSe2

    Sajjad, M.; Singh, Nirpendra; Schwingenschlö gl, Udo

    2018-01-01

    Based on first-principles calculations, the structural, electronic, and optical properties of monolayers PtS2 and PtSe2 are investigated. The bond stiffnesses and elastic moduli are determined by means of the spring constants and strain

  17. Benchmarking Pt and Pt-lanthanide sputtered thin films for oxygen electroreduction

    Zamburlini, Eleonora; Jensen, Kim Degn; Stephens, Ifan E.L.

    2017-01-01

    Platinum-lanthanide alloys are very promising as active and stable catalysts for the oxygen reduction reaction (ORR) in low-temperature fuel cells. We have fabricated Pt and Pt5Gd metallic thin films via (co-)sputtering deposition in an ultra-high vacuum (UHV) chamber. The electrochemical ORR...

  18. PERJANJIAN BOT (BUILD OPERATE AND TRANSFER ANTARA PT. SEAWORLD INDONESIA DENGAN PT PEMBANGUNAN JAYA ANCOL Tbk

    Arasina Chandra Adcha Mita

    2015-10-01

    Full Text Available Cooperation Cooperation BOT build operate and transfer (BOT is a form of cooperation agreements carried out between holders of land rights to the investor which holders of land rights would entitle the investor to erect a building for the duration of the agreement to transfer ownership of the building to holders of land rights after a period ofwake up in order to deliver an end. One form of the agreement made by PT. Jaya Ancol construction with vehicle manager of Sea World for 20 years ended 20 September 2014. This thesis entitled "Agreement Bot (Build Operate And Transfer between PT.Seaworld Indonesia with PT Building Jaya Ancol Tbk ". The purpose of this study was to determine the problems that arise in the implementation of BOT agreement between PT. Sea Wold Indonesia with PT. Jaya Ancol Tbk development and how its completion. The research method using normative juridical approach. Materials research using primary and secondary data, specifications research using descriptive analytical research, libraries and research tools using interviews, interview techniques and research data analysis method by means of qualitative methods. Based on the research that the differences in perception by each of the parties to cause problems in the BOT agreement. PT. Jaya Ancol development assume that the clause 8 subsection 5 of the Agreement between PT. Development Jaya Ancol Tbk and Sea World considers that the current agreement expires, PT. Sea World Indonesia handing back land and building project to PT. Jaya Ancol Tbk development, including supporting infrastructure and its management rights. The guidelines are used as Sea World Indonesia is clause 8 subsection  6 which states PT. Sea World Indonesia, have a perception extend the management for a maximum of 20 years, and shall notify in writing the Jaya Ancol no later than one year agreement period expires. PT. Sea World is obliged to hand over the building and its assets to PT

  19. Preparation and Thermoelectric Characteristics of ITO/PtRh:PtRh Thin Film Thermocouple.

    Zhao, Xiaohui; Wang, Hongmin; Zhao, Zixiang; Zhang, Wanli; Jiang, Hongchuan

    2017-12-15

    Thin film thermocouples (TFTCs) can provide more precise in situ temperature measurement for aerospace propulsion systems without disturbance of gas flow and surface temperature distribution of the hot components. ITO/PtRh:PtRh TFTC with multilayer structure was deposited on alumina ceramic substrate by magnetron sputtering. After annealing, the TFTC was statically calibrated for multiple cycles with temperature up to 1000 °C. The TFTC with excellent stability and repeatability was realized for the negligible variation of EMF in different calibration cycles. It is believed that owing to oxygen diffusion barriers by the oxidation of top PtRh layer and Schottky barriers formed at the grain boundaries of ITO, the variation of the carrier concentration of ITO film is minimized. Meanwhile, the life time of TFTC is more than 30 h in harsh environment. This makes ITO/PtRh:PtRh TFTC a promising candidate for precise surface temperature measurement of hot components of aeroengines.

  20. Time-invariant PT product and phase locking in PT -symmetric lattice models

    Joglekar, Yogesh N.; Onanga, Franck Assogba; Harter, Andrew K.

    2018-01-01

    Over the past decade, non-Hermitian, PT -symmetric Hamiltonians have been investigated as candidates for both a fundamental, unitary, quantum theory and open systems with a nonunitary time evolution. In this paper, we investigate the implications of the former approach in the context of the latter. Motivated by the invariance of the PT (inner) product under time evolution, we discuss the dynamics of wave-function phases in a wide range of PT -symmetric lattice models. In particular, we numerically show that, starting with a random initial state, a universal, gain-site location dependent locking between wave-function phases at adjacent sites occurs in the PT -symmetry-broken region. Our results pave the way towards understanding the physically observable implications of time invariants in the nonunitary dynamics produced by PT -symmetric Hamiltonians.

  1. Single crystal study of the heavy-fermion antiferromagnet CePt2In7

    Tobash, Paul H; Ronning, F; Thompson, J D; Scott, B L; Bauer, E D; Moll, P J W; Batlogg, B

    2012-01-01

    We report the synthesis, structure, and physical properties of single crystals of CePt 2 In 7 . Single crystal x-ray diffraction analysis confirms the tetragonal I4/mmm structure of CePt 2 In 7 with unit cell parameters a = 4.5886(6) Å, c = 21.530(6) Å and V = 453.32(14) Å 3 . The magnetic susceptibility, heat capacity, Hall effect and electrical resistivity measurements are all consistent with CePt 2 In 7 undergoing an antiferromagnetic order transition at T N = 5.5 K, which is field independent up to 9 T. Above T N , the Sommerfeld coefficient of specific heat is γ ≈ 300 mJ mol -1 K -2 , which is characteristic of an enhanced effective mass of itinerant charge carriers. The electrical resistivity is typical of heavy-fermion behavior and gives a residual resistivity ρ 0 ∼ 0.2 µΩ cm, indicating good crystal quality. CePt 2 In 7 also shows moderate anisotropy of the physical properties that is comparable to structurally related CeMIn 5 (M = Co, Rh, Ir) heavy-fermion superconductors. (paper)

  2. PtPb nanoparticle electrocatalysts: control of activity through synthetic methods

    Ghosh, Tanushree; Matsumoto, Futoshi; McInnis, Jennifer; Weiss, Marilyn; Abruna, Hector D.; DiSalvo, Francis J.

    2009-01-01

    Solution phase synthesis of intermetallic nanoparticles without using surfactants (for catalytic applications) and subsequent control of size distribution remains a challenge: of growing interest, but not widely explored yet. To understand the questions in the syntheses of Pt containing intermetallic nanoparticles (as electrocatalysts for direct fuel cells) by using sodium naphthalide as the reducing agent, the effects of the Pt precursors' organic ligands were investigated. PtPb syntheses were studied as the model case. In particular, methods that lead to nanoparticles that are independent single crystals are desirable. Platinum acetylacetonate, which is soluble in many organic solvents, has ligands that may interfere less with nanoparticle growth and ordering. Interesting trends, contrary to expectations, were observed when precursors were injected into a reducing agent solution at high temperatures. The presence of acetylacetonate, from the precursor, on the nanoparticles was confirmed by ATR, while SEM imaging showed evidence of morphological changes in the nanoparticles with increasing reaction temperature. A definite relationship between domain size and extent of observed residue (organic material and sodium) present on the particles could be established. By varying post-reaction solvent removal techniques, room temperature crystallization of PtPb nanoparticles was also achieved. Electrochemical activity of the nanoparticles was also much higher than that of nanoparticles synthesized by previous reaction schemes using sodium naphthalide as the reducing agent. Along with the above mentioned techniques, BET, TEM, CBED, SAED, and XRD were used as characterization tools for the prepared nanoparticles.

  3. Methanol Oxidation on Pt3Sn(111) for Direct Methanol Fuel Cells: Methanol Decomposition.

    Lu, Xiaoqing; Deng, Zhigang; Guo, Chen; Wang, Weili; Wei, Shuxian; Ng, Siu-Pang; Chen, Xiangfeng; Ding, Ning; Guo, Wenyue; Wu, Chi-Man Lawrence

    2016-05-18

    PtSn alloy, which is a potential material for use in direct methanol fuel cells, can efficiently promote methanol oxidation and alleviate the CO poisoning problem. Herein, methanol decomposition on Pt3Sn(111) was systematically investigated using periodic density functional theory and microkinetic modeling. The geometries and energies of all of the involved species were analyzed, and the decomposition network was mapped out to elaborate the reaction mechanisms. Our results indicated that methanol and formaldehyde were weakly adsorbed, and the other derivatives (CHxOHy, x = 1-3, y = 0-1) were strongly adsorbed and preferred decomposition rather than desorption on Pt3Sn(111). The competitive methanol decomposition started with the initial O-H bond scission followed by successive C-H bond scissions, (i.e., CH3OH → CH3O → CH2O → CHO → CO). The Brønsted-Evans-Polanyi relations and energy barrier decomposition analyses identified the C-H and O-H bond scissions as being more competitive than the C-O bond scission. Microkinetic modeling confirmed that the vast majority of the intermediates and products from methanol decomposition would escape from the Pt3Sn(111) surface at a relatively low temperature, and the coverage of the CO residue decreased with an increase in the temperature and decrease in partial methanol pressure.

  4. Preparation and characterization of Fe{sub 3}O{sub 4}-Pt nanoparticles

    Andrade, Ângela Leão, E-mail: angelala01@hotmail.com [Federal University of Ouro Preto (UFOP), Department of Chemistry, ICEB (Brazil); Cavalcante, Luis Carlos Duarte [Federal University of Piauí (UFPI), Center of Natural Sciences (Brazil); Fabris, José Domingos [Federal University of Minas Gerais (UFMG), Department of Chemistry, ICEx (Brazil); Pereira, Márcio César [Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), Institute of Science, Engineering and Technology (Brazil); Ardisson, José Domingos [Center for the Development of the Nuclear Technology (CDTN), Laboratory of Applied Physics (Brazil); Domingues, Rosana Zacarias [Federal University of Minas Gerais (UFMG), Department of Chemistry, ICEx (Brazil)

    2017-11-15

    Pt and Pt-based nanomaterials are active anticancer drugs for their ability to inhibit the division of living cells. Nanoparticles of magnetite containing variable proportions of platinum were prepared in the laboratory. The magnetite nanoparticles with platinum (Pt-Fe{sub 3}O{sub 4}) were obtained by reducing the Fe{sup 3+} of the maghemite (γ Fe{sub 2}O{sub 3}) mixed with platinum (II) acetylacetonate and sucrose in two inversely coupled ceramic crucibles and heated in a furnace at 400 °C for 20 min. The formed carbon during this preparation acts to chemically reduce the ferric iron in maghemite. Moreover, its residual layer on the particle surface prevents the forming magnetite from oxidizing in air and helps retain the platinum in the solid mixture. The produced Pt-magnetite samples were characterized by {sup 57}Fe-Mössbauer spectroscopy, powder X-ray diffraction, scanning electron microscopy, and magnetization measurements. Measurements of AC magnetic-field-induced heating properties of the obtained nanocomposites, in aqueous solution, showed that they are suitable as a hyperthermia agent for biological applications.

  5. Residual-stress measurements

    Ezeilo, A N; Webster, G A [Imperial College, London (United Kingdom); Webster, P J [Salford Univ. (United Kingdom)

    1997-04-01

    Because neutrons can penetrate distances of up to 50 mm in most engineering materials, this makes them unique for establishing residual-stress distributions non-destructively. D1A is particularly suited for through-surface measurements as it does not suffer from instrumental surface aberrations commonly found on multidetector instruments, while D20 is best for fast internal-strain scanning. Two examples for residual-stress measurements in a shot-peened material, and in a weld are presented to demonstrate the attractive features of both instruments. (author).

  6. SFG study of methanol dissociative adsorption at Pt(1 0 0), Pt(1 1 0) and Pt(1 1 1) electrodes surfaces

    Vidal, F.; Busson, B.; Six, C.; Pluchery, O.; Tadjeddine, A.

    2002-04-01

    The Pt( hkl)/methanol in acidic solution interface which constitutes a model of the anodic part of a fuel cell is studied by infrared-visible sum frequency generation vibrational spectroscopy. Methanol dissociative adsorption leads to CO poisoning of the Pt electrode surfaces. The structure of the CO/Pt( hkl) interface depends strongly on the orientation of the surface electrode.

  7. The inclusion of weld residual stress in fracture margin assessments of embrittled nuclear reactor pressure vessels

    Dickson, T.L.; Bass, B.R.; McAfee, W.J.

    1998-01-01

    Analyses were performed to determine the impact of weld residual stresses in a reactor pressure vessel (RPV) on (1) the generation of pressure temperature (P-T) curves required for maintaining specified fracture prevention margins during nuclear plant startup and shutdown, and (2) the conditional probability of vessel failure due to pressurized thermal shock (PTS) loading. The through wall residual stress distribution in an axially oriented weld was derived using measurements taken from a shell segment of a canceled RPV and finite element thermal stress analyses. The P-T curve derived from the best estimate load analysis and a t / 8 deep flaw, based on K Ic , was less limiting than the one derived from the current methodology prescribed in the ASME Boiler and Pressure Vessel Code. The inclusion of the weld residual stresses increased the conditional probability of cleavage fracture due to PTS loading by a factor ranging from 2 to 4

  8. Dehydrogenation of benzene on Pt(111) surface

    Gao, W.; Zheng, W. T.; Jiang, Q.

    2008-10-01

    The dehydrogenation of benzene on Pt(111) surface is studied by ab initio density functional theory. The minimum energy pathways for benzene dehydrogenation are found with the nudge elastic band method including several factors of the associated barriers, reactive energies, intermediates, and transient states. The results show that there are two possible parallel minimum energy pathways on the Pt(111) surface. Moreover, the tilting angle of the H atom in benzene can be taken as an index for the actual barrier of dehydrogenation. In addition, the properties of dehydrogenation radicals on the Pt(111) surface are explored through their adsorption energy, adsorption geometry, and electronic structure on the surface. The vibrational frequencies of the dehydrogenation radicals derived from the calculations are in agreement with literature data.

  9. PT symmetric Aubry–Andre model

    Yuce, C.

    2014-01-01

    PT symmetric Aubry–Andre model describes an array of N coupled optical waveguides with position-dependent gain and loss. We show that the reality of the spectrum depends sensitively on the degree of quasi-periodicity for small number of lattice sites. We obtain the Hofstadter butterfly spectrum and discuss the existence of the phase transition from extended to localized states. We show that rapidly changing periodical gain/loss materials almost conserve the total intensity. - Highlights: • We show that PT symmetric Aubry–Andre model may have real spectrum. • We show that the reality of the spectrum depends sensitively on the degree of disorder. • We obtain the Hofstadter butterfly spectrum for PT symmetric Aubry–Andre model. • We discuss that phase transition from extended to localized states exists

  10. PT symmetric Aubry–Andre model

    Yuce, C., E-mail: cyuce@anadolu.edu.tr

    2014-06-13

    PT symmetric Aubry–Andre model describes an array of N coupled optical waveguides with position-dependent gain and loss. We show that the reality of the spectrum depends sensitively on the degree of quasi-periodicity for small number of lattice sites. We obtain the Hofstadter butterfly spectrum and discuss the existence of the phase transition from extended to localized states. We show that rapidly changing periodical gain/loss materials almost conserve the total intensity. - Highlights: • We show that PT symmetric Aubry–Andre model may have real spectrum. • We show that the reality of the spectrum depends sensitively on the degree of disorder. • We obtain the Hofstadter butterfly spectrum for PT symmetric Aubry–Andre model. • We discuss that phase transition from extended to localized states exists.

  11. PT-symmetry management in oligomer systems

    Horne, R L; Cuevas, J; Kevrekidis, P G; Whitaker, N; Abdullaev, F Kh; Frantzeskakis, D J

    2013-01-01

    We study the effects of management of the PT-symmetric part of the potential within the setting of Schrödinger dimer and trimer oligomer systems. This is done by rapidly modulating in time the gain/loss profile. This gives rise to a number of interesting properties of the system, which are explored at the level of an averaged equation approach. Remarkably, this rapid modulation provides for a controllable expansion of the region of exact PT-symmetry, depending on the strength and frequency of the imposed modulation. The resulting averaged models are analysed theoretically and their exact stationary solutions are translated into time-periodic solutions through the averaging reduction. These are, in turn, compared with the exact periodic solutions of the full non-autonomous PT-symmetry managed problem and very good agreement is found between the two. (paper)

  12. Designing with residual materials

    Walhout, W.; Wever, R.; Blom, E.; Addink-Dölle, L.; Tempelman, E.

    2013-01-01

    Many entrepreneurial businesses have attempted to create value based on the residual material streams of third parties. Based on ‘waste’ materials they designed products, around which they built their company. Such activities have the potential to yield sustainable products. Many of such companies

  13. Relaxor-PT Single Crystal Piezoelectric Sensors

    Xiaoning Jiang

    2014-07-01

    Full Text Available Relaxor-PbTiO3 piezoelectric single crystals have been widely used in a broad range of electromechanical devices, including piezoelectric sensors, actuators, and transducers. This paper reviews the unique properties of these single crystals for piezoelectric sensors. Design, fabrication and characterization of various relaxor-PT single crystal piezoelectric sensors and their applications are presented and compared with their piezoelectric ceramic counterparts. Newly applicable fields and future trends of relaxor-PT sensors are also suggested in this review paper.

  14. Colloidal Toolbox Synthesis of Pt Nanoalloys

    Spanos, Ioannis

    /precipitation technique, which is commonly used in industrial synthesis offuel cell catalysts, will serve as reference. In this particular method, due to the slow rate of themetal precursor reduction and conversion to the metallic state and the even slower diffusion of themetal species on the surface of the carbon......Co1-x nanoalloys, the so-called particledisorder, with the lattice strain. Alloying Pt with increasing amount of Co increases strain andparticle disorder and subsequently both ORR performance and NPs stability. However, excessivealloying and de-alloying, as in the case of PtCo6, leads to particle...

  15. Carbon supported nanoparticles Pt Ru (Pt Ru/C electrocatalysts) prepared using electron beam irradiation; Preparacao de nanoparticulas de PtRu suportadas em carbono (eletrocatalisadores PtRu/C) utilizando feixe de eletrons

    Silva, Dionisio F. da; Oliveira Neto, Almir; Pino, Eddy S.; Linardi, Marcelo; Spinace, Estevam V. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Programa de Celulas a Combustivel], e-mail: espinace@ipen.br, e-mail: dfsilva@ipen.br

    2006-07-01

    Carbon-supported Pt Ru (electrocatalysts PtRu/C nanoparticles) were prepared submitting a water/ethylene glycol mixture containing Pt(IV) and Ru(III) ions and the carbon support to electron beam irradiation. The PtRu/C electrocatalysts were characterized by EDX, XRD and cyclic voltammetry and tested for methanol electro-oxidation aiming fuel cell application. The obtained PtRu/C electrocatalysts were more active for methanol electro-oxidation than the commercial PtRu/C ETEK electrocatalyst at ambient temperature. (author)

  16. Multifunctional Pt(II) Reagents: Covalent Modifications of Pt Complexes Enable Diverse Structural Variation and In-Cell Detection.

    White, Jonathan D; Haley, Michael M; DeRose, Victoria J

    2016-01-19

    To enhance the functionality of Pt-based reagents, several strategies have been developed that utilize Pt compounds modified with small, reactive handles. This Account encapsulates work done by us and other groups regarding the use of Pt(II) compounds with reactive handles for subsequent elaboration with fluorophores or other functional moieties. Described strategies include the incorporation of substituents for well-known condensation or nucleophilic displacement-type reactions and their use, for example, to tether spectroscopic handles to Pt reagents for in vivo investigation. Other chief uses of displacement-type reactions have included tethering various small molecules exhibiting pharmacological activity directly to Pt, thus adding synergistic effects. Click chemistry-based ligation techniques have also been applied, primarily with azide- and alkyne-appended Pt complexes. Orthogonally reactive click chemistry reactions have proven invaluable when more traditional nucleophilic displacement reactions induce side-reactivity with the Pt center or when systematic functionalization of a larger number of Pt complexes is desired. Additionally, a diverse assortment of Pt-fluorophore conjugates have been tethered via click chemistry conjugation. In addition to providing a convenient synthetic path for diversifying Pt compounds, the use of click-capable Pt complexes has proved a powerful strategy for postbinding covalent modification and detection with fluorescent probes. This strategy bypasses undesirable influences of the fluorophore camouflaged as reactivity due to Pt that may be present when detecting preattached Pt-fluorophore conjugates. Using postbinding strategies, Pt reagent distributions in HeLa and lung carcinoma (NCI-H460) cell cultures were observed with two different azide-modified Pt compounds, a monofunctional Pt(II)-acridine type and a difunctional Pt(II)-neutral complex. In addition, cellular distribution was observed with an alkyne-appended difunctional

  17. Mechanisms of current conduction in Pt/BaTiO3/Pt resistive switching cell

    Pan, R.K.; Zhang, T.J.; Wang, J.Y.; Wang, J.Z.; Wang, D.F.; Duan, M.G.

    2012-01-01

    The 80-nm-thickness BaTiO 3 (BT) thin film was prepared on the Pt/Ti/SiO 2 /Si substrate by the RF magnetron sputtering technique. The Pt/BT/Pt/Ti/SiO 2 /Si structure was investigated using X-ray diffraction and scanning electron microscopy. The current–voltage characteristic measurements were performed. The bipolar resistive switching behavior was found in the Pt/BT/Pt cell. The current–voltage curves were well fitted in different voltage regions at the high resistance state (HRS) and the low resistance state (LRS), respectively. The conduction mechanisms are concluded to be Ohmic conduction and Schottky emission at the LRS, while space-charge-limited conduction and Poole–Frenkel emission at the HRS. The electroforming and switching processes were explained in terms of the valence change mechanism, in which oxygen vacancies play a key role in forming conducting paths. - Highlights: ►Pt/BaTiO 3 /Pt cell shows the bipolar resistive switching behavior. ►The current–voltage curves were well fitted for different conduction mechanisms. ►The electroforming and switching processes were explained.

  18. CO tolerance of PdPt/C and PdPtRu/C anodes for PEMFC

    Garcia, Amanda C.; Paganin, Valdecir A.; Ticianelli, Edson A.

    2008-01-01

    The performance of H 2 /O 2 proton exchange membrane fuel cells (PEMFCs) fed with CO-contaminated hydrogen was investigated for anodes with PdPt/C and PdPtRu/C electrocatalysts. The physicochemical properties of the catalysts were characterized by energy dispersive X-ray (EDX) analyses, X-ray diffraction (XRD) and 'in situ' X-ray absorption near edge structure (XANES). Experiments were conducted in electrochemical half and single cells by cyclic voltammetry (CV) and I-V polarization measurements, while DEMS was employed to verify the formation of CO 2 at the PEMFC anode outlet. A quite high performance was achieved for the PEMFC fed with H 2 + 100 ppm CO with the PdPt/C and PdPtRu/C anodes containing 0.4 mg metal cm -2 , with the cell presenting potential losses below 200 mV at 1 A cm -2 , with respect to the system fed with pure H 2 . For the PdPt/C catalysts no CO 2 formation was seen at the PEMFC anode outlet, indicating that the CO tolerance is improved due to the existence of more free surface sites for H 2 electrooxidation, probably due to a lower Pd-CO interaction compared to pure Pd or Pt. For PdPtRu/C the CO tolerance may also have a contribution from the bifunctional mechanism, as shown by the presence of CO 2 in the PEMFC anode outlet

  19. Sintering of Pt nanoparticles via volatile PtO_2: Simulation and comparison with experiments

    Plessow, Philipp N.; Abild-Pedersen, Frank

    2016-01-01

    It is a longstanding question whether sintering of platinum under oxidizing conditions is mediated by surface migration of Pt species or through the gas phase, by PtO_2(g). Clearly, a rational approach to avoid sintering requires understanding the underlying mechanism. A basic theory for the simulation of ripening through the vapor phase has been derived by Wynblatt and Gjostein. Recent modeling efforts, however, have focused entirely on surface-mediated ripening. In this work, we explicitly model ripening through PtO_2(g) and study how oxygen pressure, temperature, and shape of the particle size distribution affect sintering. On the basis of the available data on α-quartz, adsorption of monomeric Pt species on the support is extremely weak and has therefore not been explicitly simulated, while this may be important for more strongly interacting supports. Our simulations clearly show that ripening through the gas phase is predicted to be relevant. Assuming clean Pt particles, sintering is generally overestimated. This can be remedied by explicitly including oxygen coverage effects that lower both surface free energies and the sticking coefficient of PtO_2(g). Additionally, mass-transport limitations in the gas phase may play a role. Using a parameterization that accounts for these effects, we can quantitatively reproduce a number of experiments from the literature, including pressure and temperature dependence. Lastly, this substantiates the hypothesis of ripening via PtO_2(g) as an alternative to surface-mediated ripening.

  20. Ion-irradiation induced chemical ordering of FePt and FePtAu nanoparticles

    Seetala, Naidu V. [Department of Physics, Grambling State University, RWE Jones Drive, Carver Hall 81, Grambling, LA 71245 (United States)]. E-mail: naidusv@gram.edu; Harrell, J.W. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Lawson, Jeremy [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Nikles, David E. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Williams, John R. [Department of Physics, Auburn University, Auburn, AL 36849 (United States); Isaacs-Smith, Tamara [Department of Physics, Auburn University, Auburn, AL 36849 (United States)

    2005-12-15

    We have studied the effect of ion-beam irradiation on reducing the ordering temperature of FePt and FePtAu nanoparticles. FePt and FePt(Au14%) 4 nm particles dispersed on a Si-substrate were irradiated by 300 keV Al-ions with a dose of 1 x 10{sup 16} ions/cm{sup 2} at 43 {sup o}C using a water-cooled flange in order to minimize the vacancy migration and voids formation within the collision cascades. Partial chemical ordering has been observed in as-irradiated particles with coercivity of 60-130 Oe. Post-irradiation annealing at 220 {sup o}C enhanced chemical ordering in FePt nanoparticles with coercivity of 3500 Oe, magnetic anisotropy of 1.5 x 10{sup 7} erg/cc, and thermal stability factor of 130. A much higher 375 {sup o}C post-irradiation annealing was required in FePtAu, presumably because Au atoms were trapped at Fe/Pt lattice sites at lower temperatures. As the annealing temperature increased, anomalous features in the magnetization reversal curves were observed that disappeared at higher annealing temperatures.

  1. Pt/Cr and Pt/Ni catalysts for oxygen reduction reaction: to alloy or not to alloy?

    Escaño, Mary Clare; Gyenge, Elod; Nakanishi, Hiroshi; Kasai, Hideaki

    2011-04-01

    Bimetallic systems such as Pt-based alloys or non-alloys have exhibited interesting catalytic properties but pose a major challenge of not knowing a priori how the electronic and chemical properties will be modified relative to the parent metals. In this work, we present the origin of the changes in the reactivity of Pt/Cr and Pt/Ni catalysts, which have been of wide interest in fuel cell research. Using spin-polarized density functional theory calculations, we have shown that the modification of Pt surface reactivity in Pt/Ni is purely of geometric origin (strain). We have also found that the Pt-Ni bonding is very weak, which explains the observed instability of Pt-Ni catalysts under electrochemical measurements. On the other hand, Pt/Cr systems are governed by strong ligand effect (metal-metal interaction), which explains the experimentally observed reactivity dependence on the relative composition of the alloying components. The general characteristics of the potential energy curves for O2 dissociative adsorption on the bimetallic systems and the pure Pt clarify why the d-band center still works for Pt/Cr despite the strong Pt-Cr bonding and high spin polarization of Pt d-states. On the basis of the above clarifications, viable Pt-Cr and Pt-Ni structures, which involve nano-sized alloys and non-alloy bulk catalyst, which may strike higher than the currently observed oxidation reduction reaction activity are proposed.

  2. Sol-Gel Process for Making Pt-Ru Fuel-Cell Catalysts

    Narayanan, Sekharipuram; Valdez, Thomas; Kumta, Prashant; Kim, Y.

    2005-01-01

    A sol-gel process has been developed as a superior alternative to a prior process for making platinum-ruthenium alloy catalysts for electro-oxidation of methanol in fuel cells. The starting materials in the prior process are chloride salts of platinum and ruthenium. The process involves multiple steps, is time-consuming, and yields a Pt-Ru product that has relatively low specific surface area and contains some chloride residue. Low specific surface area translates to incomplete utilization of the catalytic activity that might otherwise be available, while chloride residue further reduces catalytic activity ("poisons" the catalyst). In contrast, the sol-gel process involves fewer steps and less time, does not leave chloride residue, and yields a product of greater specific area and, hence, greater catalytic activity. In this sol-gel process (see figure), the starting materials are platinum(II) acetylacetonate [Pt(C5H7O2)2, also denoted Pt-acac] and ruthenium(III) acetylacetonate [Ru(C5H7O2)3, also denoted Ru-acac]. First, Pt-acac and Ru-acac are dissolved in acetone at the desired concentrations (typically, 0.00338 moles of each salt per 100 mL of acetone) at a temperature of 50 C. A solution of 25 percent tetramethylammonium hydroxide [(CH3)4NOH, also denoted TMAH] in methanol is added to the Pt-acac/Ruacac/ acetone solution to act as a high-molecular-weight hydrolyzing agent. The addition of the TMAH counteracts the undesired tendency of Pt-acac and Ru-acac to precipitate as separate phases during the subsequent evaporation of the solvent, thereby helping to yield a desired homogeneous amorphous gel. The solution is stirred for 10 minutes, then the solvent is evaporated until the solution becomes viscous, eventually transforming into a gel. The viscous gel is dried in air at a temperature of 170 C for about 10 hours. The dried gel is crushed to make a powder that is the immediate precursor of the final catalytic product. The precursor powder is converted to the

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

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

    2013-01-01

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

  4. Effect of the applied magnetic field and the layer thickness on the magnon properties in bilayers Co/Pt and symmetrical trilayer Pt/Co/Pt

    Mehdioui, M.; Fahmi, A.; Lassri, H.; Fahoume, M.; Qachaou, A.

    2014-01-01

    We have studied the elementary magnetic excitations and their dynamics in multilayer Co(t Co)/Pt(t Pt) and Pt(t Pt)/Co(t Co)/Pt(t Pt) under an applied magnetic field. The Heisenberg hamiltonian used takes into account the magneto-crystalline and surface anisotropies, the exchange and dipolar interactions. The calculated excitation spectrum ε N (k) presents a structure with two sub-bands corresponding to the magnons of surface and volume respectively. The existence of a gap of creating these magnons is also highlighted. The lifetimes deduced from these gaps are in good agreement with the results of previous studies. The thermal evolution of the magnetization m z indicates that the system undergoes a dimensional crossover 3D–2D when the temperature increases. The calculated and measured magnetizations are compared and they are in good agreement. The exchange integral and critical temperature values deduced from these adjustments are in very good agreement with the results of previous works. - Highlights: • The magnons of surface and volume exist in Co/Pt and Pt/Co/Pt. • Samples undergo dimensional crossover (3D–2D) when T increases. • A good agreement is obtained between M(T) measured and calculated. • Deduced exchange integrals and critical temperature values are correct. • The magnetism of the sample is reduced by increasing t Pt or capping Co by two Pt layers

  5. Pt/MOx/SiO2, Pt/MOx/TiO2, and Pt/MOx/Al2O3 Catalysts for CO Oxidation

    Hongmei Qin

    2015-04-01

    Full Text Available Conventional supported Pt catalysts have often been prepared by loading Pt onto commercial supports, such as SiO2, TiO2, Al2O3, and carbon. These catalysts usually have simple metal-support (i.e., Pt-SiO2 interfaces. To tune the catalytic performance of supported Pt catalysts, it is desirable to modify the metal-support interfaces by incorporating an oxide additive into the catalyst formula. Here we prepared three series of metal oxide-modified Pt catalysts (i.e., Pt/MOx/SiO2, Pt/MOx/TiO2, and Pt/MOx/Al2O3, where M = Al, Fe, Co, Cu, Zn, Ba, La for CO oxidation. Among them, Pt/CoOx/SiO2, Pt/CoOx/TiO2, and Pt/CoOx/Al2O3 showed the highest catalytic activities. Relevant samples were characterized by N2 adsorption-desorption, X-ray diffraction (XRD, transmission electron microscopy (TEM, H2 temperature-programmed reduction (H2-TPR, X-ray photoelectron spectroscopy (XPS, CO temperature-programmed desorption (CO-TPD, O2 temperature-programmed desorption (O2-TPD, and CO2 temperature-programmed desorption (CO2-TPD.

  6. The Pt site reactivity of the molecular graphs of Au6Pt isomers

    Xu, Tianlv; Jenkins, Samantha; Xiao, Chen-Xia; Maza, Julio R.; Kirk, Steven R.

    2013-12-01

    Within the framework of the theory of atoms in molecules (QTAIM), in an exploratory study we propose a new measure of site reactivity equivalent to the atomic coordination number based purely on the electronic structure. It was found that the number of ring critical points (NNRCPs) positioned on the boundary of the atomic basin of the dopant (Pt) nucleus correlated very well with the relative zero point energy (ZPE) corrected energies. A weaker condition (i.e. than the number of associated bond paths) for the association of the dopant Pt nucleus with the Au6Pt molecular graph is found for NNRCP = 0.

  7. Pt-graphene electrodes for dye-sensitized solar cells

    Hoshi, Hajime; Tanaka, Shumpei; Miyoshi, Takashi

    2014-01-01

    Highlights: • Graphene films with Pt nanoparticles were prepared from commercial graphene. • Pt consumption can be reduced by using Pt-graphene films. • The film showed improved catalytic activity for the reaction I 3 − /I − . • The film can be used as the counter electrode of dye-sensitized solar cells (DSSCs). • The performance of DSSC was superior to that of the Pt electrode. - Abstract: A simple paste method for fabricating graphene films with Pt nanoparticles was developed. First, graphene pastes with Pt nanoparticles were prepared from commercially available graphene. The resulting films of graphene nanoplatelet aggregates with Pt nanoparticles (Pt-GNA) contained Pt nanoparticles distributed over the entire three-dimensional surface of the GNA. Then, the catalytic activity for the I 3 − /I − redox reaction was evaluated by cyclic voltammetry. The GNA electrode exhibited higher activity than a graphene nanoplatelet electrode because of its higher effective surface area. Addition of Pt nanoparticles to the electrodes improved the catalytic activity. In particular, a large Faradaic current for the I 3 − /I − reaction was observed for the Pt-GNA electrode. As the counter electrodes of dye-sensitized solar cells (DSSCs), their performance was consistent with the cyclic voltammetry results. In particular, the DSSC performance of the Pt-GNA electrode was superior to that of the Pt electrodes commonly used in DSSCs

  8. Pt-graphene electrodes for dye-sensitized solar cells

    Hoshi, Hajime, E-mail: hoshi@ed.tus.ac.jp; Tanaka, Shumpei; Miyoshi, Takashi

    2014-12-15

    Highlights: • Graphene films with Pt nanoparticles were prepared from commercial graphene. • Pt consumption can be reduced by using Pt-graphene films. • The film showed improved catalytic activity for the reaction I{sub 3}{sup −}/I{sup −}. • The film can be used as the counter electrode of dye-sensitized solar cells (DSSCs). • The performance of DSSC was superior to that of the Pt electrode. - Abstract: A simple paste method for fabricating graphene films with Pt nanoparticles was developed. First, graphene pastes with Pt nanoparticles were prepared from commercially available graphene. The resulting films of graphene nanoplatelet aggregates with Pt nanoparticles (Pt-GNA) contained Pt nanoparticles distributed over the entire three-dimensional surface of the GNA. Then, the catalytic activity for the I{sub 3}{sup −}/I{sup −} redox reaction was evaluated by cyclic voltammetry. The GNA electrode exhibited higher activity than a graphene nanoplatelet electrode because of its higher effective surface area. Addition of Pt nanoparticles to the electrodes improved the catalytic activity. In particular, a large Faradaic current for the I{sub 3}{sup −}/I{sup −} reaction was observed for the Pt-GNA electrode. As the counter electrodes of dye-sensitized solar cells (DSSCs), their performance was consistent with the cyclic voltammetry results. In particular, the DSSC performance of the Pt-GNA electrode was superior to that of the Pt electrodes commonly used in DSSCs.

  9. Density functional theory studies of the adsorption of ethylene and oxygen on Pt(111) and Pt3Sn(111)

    Watwe, R.M.; Cortright, R.D.; Mavrikakis, Manos

    2001-01-01

    Density functional theory, employing periodic slab calculations, was used to investigate the interactions of ethylene and oxygen with Pt(111) and Pt3Sn(111). The predicted energetics and structures of adsorbed species on Pt(111) are in good agreement with experimental data. The binding energies...... more than adsorption on two-fold and one-fold sites. Oxygen atoms bond as strongly on Pt3Sn(111) as on Pt(111), and these atoms prefer to adsorb near Sn atoms on the surface. The addition of Sn to Pt(111) leads to a surface heterogeneity, wherein ethylidyne species prefer to adsorb away from Sn atoms...

  10. Failure characteristics and mechanisms of EB-PVD TBCs with Pt-modified NiAl bond coats

    Zhou, Le; Mukherjee, Sriparna; Huang, Ke; Park, Young Whan; Sohn, Yongho, E-mail: Yongho.Sohn@ucf.edu

    2015-06-18

    Microstructural evolution and failure characteristics/mechanisms were investigated for thermal barrier coatings that consist of electron beam physical vapor deposited ZrO{sub 2}−8 wt% Y{sub 2}O{sub 3} (YSZ) topcoat, Pt-modified nickel aluminide, (Ni,Pt)Al bond coat, and CMSX-4 superalloy substrate with furnace cycling at 1100 °C with 1-h dwell. Photo stimulated luminescence spectroscopy, scanning electron microscopy equipped with X-ray energy dispersive spectroscopy and transmission electron microscopy were employed to examine the residual stress of the thermally grown oxide (TGO) and microstructural changes. For comparison, (Ni,Pt)Al bond coat on CMSX-4 without the YSZ topcoat was also characterized. The TGO grew faster for the YSZ-coated (Ni,Pt)Al bond coat than the (Ni,Pt)Al coating without the YSZ topcoat. Correspondingly, the β-to-γ′/martensite formation in the (Ni,Pt)Al bond coat occurred faster on the YSZ-coated (Ni,Pt)Al bond coat. However the rumpling occurred much faster and with larger amplitude on the (Ni,Pt)Al coating without the YSZ topcoat. Still, the rumpling at the TGO/bond coat interface caused crack initiation as early as 10 thermal cycles, decohesion at the YSZ/TGO interface, and eventual spallation failure primarily through the TGO/bond coat interface. The magnitude of compressive residual stress in the TGO showed an initial increase up to 3−4 GPa followed by a gradual decrease. The rate of stress relaxation was much quicker for the TGO scale without the YSZ topcoat with distinctive relief corresponding to the cracking at the top of geometrical ridges associated with the (Ni,Pt)Al bond coat. The maximum elastic energy for the TGO scale was estimated at 90 J/m{sup 2} at 50% of its lifetime (N{sub f}=545 cycles). The YSZ presence/adhesion to the TGO scale is emphasized to minimize the undulation of the TGO/bond coat interface, i.e., decohesion at the YSZ/TGO scale accelerates the rumpling and crack-coalescence at the TGO/bond coat

  11. Studies with Pt-195M platinum complexes

    Cole, W.; Wiza, J.; Odenheimer, B.; Wolf, W.; Hoeschele, J.D.; Butler, T.A.; Smyth, R.D.

    1982-01-01

    Cis-diamine-ethylmalonato 195 Pt(II) has been synthesised to investigate its chemotherapeutic potential in cancer and other diseases. It is likely to be less nephrotoxic than the established drug crisplatin. Biodistribution and clearance studies were carried out on Sprague-Dowley rats after intravenous administration of the new drug. (author)

  12. Dynamics of the YSZ-Pt Interface

    Bay, Lasse; Jacobsen, Torben

    1997-01-01

    Yttria stabilized zirconia (YSZ)-Pt point electrodes were examined by linear potential sweep, potential step and impedance measurements at 1000 degrees C in air. Inductive loops and hysteresis phenomena with long relaxation times were found. Atomic force microscopy showed changes of the interface...

  13. Ti-Pt Alloys form mechanical milling

    Nxumalo, S

    2009-12-01

    Full Text Available C maximum in these alloys. A few researchers have studied the martensitic transformation in TiPt alloys using arc melted cast samples. In this work high temperature shape memory alloys are targeted using powder metallurgy as a processing route....

  14. Evaluation of residue-residue contact predictions in CASP9

    Monastyrskyy, Bohdan; Fidelis, Krzysztof; Tramontano, Anna; Kryshtafovych, Andriy

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures

  15. Exotic high activity surface patterns in PtAu nanoclusters

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2013-01-01

    of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active

  16. Sharing Residual Liability

    Carbonara, Emanuela; Guerra, Alice; Parisi, Francesco

    2016-01-01

    Economic models of tort law evaluate the efficiency of liability rules in terms of care and activity levels. A liability regime is optimal when it creates incentives to maximize the value of risky activities net of accident and precaution costs. The allocation of primary and residual liability...... for policy makers and courts in awarding damages in a large number of real-world accident cases....

  17. Efficient decomposition of formaldehyde at room temperature over Pt/honeycomb ceramics with ultra-low Pt content.

    Nie, Longhui; Zheng, Yingqiu; Yu, Jiaguo

    2014-09-14

    Pt/honeycomb ceramic (Pt/HC) catalysts with ultra-low Pt content (0.005-0.055 wt%) were for the first time prepared by an impregnation of honeycomb ceramics with Pt precursor and NaBH4-reduction combined method. The microstructures, morphologies and textural properties of the resulting samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The obtained Pt/HC catalysts were used for catalytic oxidative decomposition of formaldehyde (HCHO) at room temperature. It was found that the as-prepared Pt/HC catalysts can efficiently decompose HCHO in air into CO2 and H2O at room temperature. The catalytic activity of the Pt/HC catalysts increases with increasing the Pt loading in the range of 0.005-0.013 wt%, and the further increase of the Pt loading does not obviously improve catalytic activity. From the viewpoint of cost and catalytic performance, 0.013 wt% Pt loading is the optimal Pt loading amount, and the Pt/HC catalyst with 0.013 wt% Pt loading also exhibited good catalytic stability. Considering practical applications, this work will provide new insights into the low-cost and large-scale fabrication of advanced catalytic materials for indoor air purification.

  18. Preparation and characterization of Pt/C and Pt sbnd Ru/C electrocatalysts for direct ethanol fuel cells

    Liu, Zhaolin; Ling, Xing Yi; Su, Xiaodi; Lee, Jim Yang; Gan, Leong Ming

    Nano-sized Pt and Pt sbnd Ru colloids are prepared by a microwave-assisted polyol process, and transferred to a toluene solution of decanthiol. Vulcan XC-72 is then added to the toluene solution to adsorb the thiolated Pt and Pt sbnd Ru colloids. Transmission electron microscopy examinations show nearly spherical particles and narrow size distributions for both supported and unsupported metals. The carbon-supported Pt and Pt sbnd Ru nanoparticles are activated by thermal treatment to remove the thiol stabilizing shell. All Pt and Pt sbnd Ru catalysts (except Pt 23sbnd Ru 77) give the X-ray diffraction pattern of a face-centered cubic (fcc) crystal structure, whereas the Pt 23sbnd Ru 77 alloy is more typical of the hexagonal close packed (hcp) structure. The electro-oxidation of liquid ethanol on these catalysts is investigated at room temperature by cyclic voltammetry. The results demonstrate that the alloy catalyst is catalytically more active than pure platinum. Preliminary tests on a single cell of a direct ethanol fuel cell (DEFC) indicate that a Pt 52sbnd Ru 48/C anode catalyst gives the best electrocatalytic performance among all the carbon-supported Pt and Pt sbnd Ru catalysts.

  19. Preparation and characterization of Pt/C and Pt-Ru/C electrocatalysts for direct ethanol fuel cells

    Liu, Zhaolin; Ling, Xing Yi; Su, Xiaodi; Lee, Jim Yang; Gan, Leong Ming [Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 (Singapore)

    2005-09-26

    Nano-sized Pt and Pt-Ru colloids are prepared by a microwave-assisted polyol process, and transferred to a toluene solution of decanthiol. Vulcan XC-72 is then added to the toluene solution to adsorb the thiolated Pt and Pt-Ru colloids. Transmission electron microscopy examinations show nearly spherical particles and narrow size distributions for both supported and unsupported metals. The carbon-supported Pt and Pt-Ru nanoparticles are activated by thermal treatment to remove the thiol stabilizing shell. All Pt and Pt-Ru catalysts (except Pt{sub 23}-Ru{sub 77}) give the X-ray diffraction pattern of a face-centered cubic (fcc) crystal structure, whereas the Pt{sub 23}-Ru{sub 77} alloy is more typical of the hexagonal close packed (hcp) structure. The electro-oxidation of liquid ethanol on these catalysts is investigated at room temperature by cyclic voltammetry. The results demonstrate that the alloy catalyst is catalytically more active than pure platinum. Preliminary tests on a single cell of a direct ethanol fuel cell (DEFC) indicate that a Pt{sub 52}-Ru{sub 48}/C anode catalyst gives the best electrocatalytic performance among all the carbon-supported Pt and Pt-Ru catalysts. (author)

  20. A label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) based on platinum (II)-oligonucleotide coordination induced gold nanoparticles aggregation.

    Fan, Daoqing; Zhai, Qingfeng; Zhou, Weijun; Zhu, Xiaoqing; Wang, Erkang; Dong, Shaojun

    2016-11-15

    Herein, a gold nanoparticles (AuNPs) based label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) was constructed for the first time. Four bases (G-G mismatch) mismatched streptavidin aptamer (MSAA) was used to protect AuNPs from salt-induced aggregation and recognize Pt (II) specifically. Only in the presence of Pt (II), coordination occurs between G-G bases and Pt (II), leading to the activation of streptavidin aptamer. Streptavidin coated magnetic beads (MBs) were used as separation agent to separate Pt (II)-coordinated MSAA. The residual less amount of MSAA could not efficiently protect AuNPs anymore and aggregation of AuNPs will produce a colorimetric product. With the addition of Pt (II), a pale purple-to-blue color variation could be observed by the naked eye. A detection limit of 150nM and a linear range from 0.6μM to 12.5μM for Pt (II) could be achieved without any amplification. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. All-optical measurement of interlayer exchange coupling in Fe/Pt/FePt thin films

    Berk, C.; Ganss, F.; Jaris, M.; Albrecht, M.; Schmidt, H.

    2018-01-01

    Time Resolved Magneto Optic Kerr Effect spectroscopy was used to all-optically study the dynamics in exchange coupled Fe(10 nm)/Pt(x = 0-5 nm)/FePt (10 nm) thin films. As the Pt spacer decreases, the effective magnetization of the layers is seen to evolve towards the strong coupling limit where the two films can be described by a single effective magnetization. The coupling begins at x = 1.5 nm and reaches a maximum exchange coupling constant of 2.89 erg/cm2 at x = 0 nm. The films are ferromagnetically coupled at all Pt thicknesses in the exchange coupled regime (x ≤ 1.5 nm). A procedure for extracting the interlayer exchange constant by measuring the magnetic precession frequencies at multiple applied fields and angles is outlined. The dynamics are well reproduced using micromagnetic simulations.

  2. Determination of the apparent transfer coefficient for CO oxidation on Pt(poly), Pt(111), Pt(665) and Pt(332) using a potential modulation technique.

    Wang, Han-Chun; Ernst, Siegfried; Baltruschat, Helmut

    2010-03-07

    The apparent transfer coefficient, which gives the magnitude of the potential dependence of the electrochemical reaction rates, is the key quantity for the elucidation of electrochemical reaction mechanisms. We introduce the application of an ac method to determine the apparent transfer coefficient alpha' for the oxidation of pre-adsorbed CO at polycrystalline and single-crystalline Pt electrodes in sulfuric acid. The method allows to record alpha' quasi continuously as a function of potential (and time) in cyclic voltammetry or at a fixed potential, with the reaction rate varying with time. At all surfaces (Pt(poly), Pt(111), Pt(665), and Pt(332)) we clearly observed a transition of the apparent transfer coefficient from values around 1.5 at low potentials to values around 0.5 at higher potentials. Changes of the apparent transfer coefficients for the CO oxidation with potential were observed previously, but only from around 0.7 to values as low as 0.2. In contrast, our experimental findings completely agree with the simulation by Koper et al., J. Chem. Phys., 1998, 109, 6051-6062. They can be understood in the framework of a Langmuir-Hinshelwood mechanism. The transition occurs when the sum of the rate constants for the forward reaction (first step: potential dependent OH adsorption, second step: potential dependent oxidation of CO(ad) with OH(ad)) exceeds the rate constant for the back-reaction of the first step. We expect that the ac method for the determination of the apparent transfer coefficient, which we used here, will be of great help also in many other cases, especially under steady conditions, where the major limitations of the method are avoided.

  3. O PT e o impeachment de Collor

    Danilo Enrico Martuscelli

    2010-11-01

    Full Text Available Este artigo analisa a tática política adotada pelo Partido dos Trabalhadores (PT na conjuntura de crise do governo Collor (1990-1992. Considera-se que o PT não tenha fugido à tendência dominante do movimento pró-impeachment, vindo a aderir à campanha pela ética na política e a atacar o presidente Collor a partir de um discurso de cunho moralista que menosprezou a crítica e a denúncia do caráter de classe da política neoliberal, satisfazendo-se apenas com a denúncia da política recessiva do governo. Essa tática se inscreve na luta contra os efeitos da política neoliberal e não propriamente contra essa política, e esse comportamento político pode ser considerado um indicador do processo de aceitação passiva, por parte do PT, das medidas neoliberais.This paper analyzes Collor's government crisis and the political tactics of the Workers' Party (PT at the conjuncture of Collor's government crisis. We consider that the Workers' Party didn't escape of the dominant trend of the pro-impeachment movement, adhering to the campaign for the ethics in politics and attacking president Collor from a moralist point of view, which relegated the critics and denouncement of the class character of the neoliberal politics to the second plan. The Party was limited to join the accusations about the recessionary trend of Collor's government, which meant a tactic inscribed in the fight against the effects of the neoliberal politics but not against its nature. This political behavior can be considered as an indicator of the process of passive acceptation of the neoliberal proposals from the PT.

  4. Rapid thermal annealing of FePt and FePt/Cu thin films

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  5. SELECTIVE HYDROGENATION OF CINNAMALDEHYDE WITH Pt AND Pt-Fe CATALYSTS: EFFECTS OF THE SUPPORT

    A.B. da Silva

    1998-06-01

    Full Text Available Low-temperature reduced TiO2-supported Pt and Pt-Fe catalysts are much more active and selective for the liquid–phase hydrogenation of cinnamaldehyde to unsaturated cinnamyl alcohol than the corresponding carbon-supported catalysts. High-temperature reduced catalysts, where the SMSI effect should be present, are almost inactive for this reaction. There is at present no definitive explanation for this effect but an electronic metal-support interaction is most probably involved.

  6. Cyclic voltammograms for H on Pt(111) and Pt(100) from first principles

    Karlberg, Gustav; Jaramillo, Thomas; Skulason, Egill

    2007-01-01

    Cyclic voltammetry is a fundamental experimental method for characterizing electrochemical surfaces. Despite its wide use, a way to quantitatively and directly relate cyclic voltammetry to ab initio calculations has been lacking. We derive the cyclic voltammogram for H on Pt(111) and Pt(100), bas...... solely on density functional theory calculations and standard molecular tables. By relating the gas phase adsorption energy to the electrochemical electrode potential, we provide a direct link between surface science and electrochemistry....

  7. Results of the Proficiency Test, PT1 and PT2, 2011

    Kahns, Søren; Nicolajsen, Nicole; Christophersen, Maj-Britt

    2012-01-01

    A comparative test of diagnostic procedures was provided by the EU Reference Laboratory (EURL) for Fish Diseases to 41 National Reference Laboratories (NRLs) in the start of middle of October 2011. The test was prepared and tested according to protocols accredited by DANAK under registration numb...... 515 to proficiency testing according to the quality assurance standard DS/EN ISO/IEC 17043. The test consisted of 2 tests: PT1 and PT2....

  8. Energetics and dynamics of Pt dimers on Pt(110)-(1x2)

    Linderoth, T.R.; Horch, S.; Petersen, L.; Helveg, S.; Schoenning, M.; Laegsgaard, E.; Stensgaard, I.; Besenbacher, F.

    2000-01-01

    The stability and dynamics of Pt dimers on Pt(110)-(1x2) are studied using fast-scanning, variable-temperature STM. The kinetics of both dissociation and association of dimers have been quantified from a direct analysis of time-lapse STM movies. The extracted barriers are at variance with results from ab initio calculations, and we speculate that the discrepancies are due to trace amounts of gas impurities such as CO

  9. Targeting lysine specific demethylase 4A (KDM4A) tandem TUDOR domain - A fragment based approach.

    Upadhyay, Anup K; Judge, Russell A; Li, Leiming; Pithawalla, Ron; Simanis, Justin; Bodelle, Pierre M; Marin, Violeta L; Henry, Rodger F; Petros, Andrew M; Sun, Chaohong

    2018-06-01

    The tandem TUDOR domains present in the non-catalytic C-terminal half of the KDM4A, 4B and 4C enzymes play important roles in regulating their chromatin localizations and substrate specificities. They achieve this regulatory role by binding to different tri-methylated lysine residues on histone H3 (H3-K4me3, H3-K23me3) and histone H4 (H4-K20me3) depending upon the specific chromatin environment. In this work, we have used a 2D-NMR based fragment screening approach to identify a novel fragment (1a), which binds to the KDM4A-TUDOR domain and shows modest competition with H3-K4me3 binding in biochemical as well as in vitro cell based assays. A co-crystal structure of KDM4A TUDOR domain in complex with 1a shows that the fragment binds stereo-specifically to the methyl lysine binding pocket forming a network of strong hydrogen bonds and hydrophobic interactions. We anticipate that the fragment 1a can be further developed into a novel allosteric inhibitor of the KDM4 family of enzymes through targeting their C-terminal tandem TUDOR domain. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Electrocatalytic activity of Pt and PtCo deposited on Ebonex by BH reduction

    Slavcheva, E.; Nikolova, V.; Petkova, T.; Lefterova, E.; Dragieva, I.; Vitanov, T.; Budevski, E.

    2005-01-01

    The method of borohydride reduction (BH) has been applied to synthesize Pt and PtCo nanoparticles supported on Magneli phase titanium oxides, using Pt and Co ethylenediamine complexes as metal precursors. The phase composition of the synthesized catalysts, their morphology and surface structure were studied by physical methods for bulk and surface analysis, such as electron microprobe analysis (EMPA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and BET technique. The catalytic activity towards oxygen evolution reaction in alkaline aqueous solution was investigated using the common electrochemical techniques. It was found that PtCo/Ebonex facilitates essentially the oxygen evolution which starts at lower overpotentials and proceeds with higher rate compared to both the supported Pt and unsupported PtCo catalysts. The observed effect is prescribed to metal-metal and metal-support interactions. The Ebonex possesses a good electrical conductivity and corrosion resistance at high anodic potentials and despite its low surface area is considered as a potential catalyst carrier for the oxygen evolution reaction

  11. Strongly bound excitons in monolayer PtS2 and PtSe2

    Sajjad, M.

    2018-01-22

    Based on first-principles calculations, the structural, electronic, and optical properties of monolayers PtS2 and PtSe2 are investigated. The bond stiffnesses and elastic moduli are determined by means of the spring constants and strain-energy relations, respectively. Dynamic stability is confirmed by calculating the phonon spectra, which shows excellent agreement with experimental reports for the frequencies of the Raman-active modes. The Heyd-Scuseria-Ernzerhof functional results in electronic bandgaps of 2.66 eV for monolayer PtS2 and 1.74 eV for monolayer PtSe2. G0W0 calculations combined with the Bethe-Salpeter equation are used to predict the optical spectra and exciton binding energies (0.78 eV for monolayer PtS2 and 0.60 eV for monolayer PtSe2). It turns out that the excitons are strongly bound and therefore very stable against external perturbations.

  12. Carbon-coated NiPt, CoPt nanoalloys: size control and magnetic properties

    El-Gendy, A.A. [Kirchhoff Institute for Physics, University of Heidelberg, D-69120 Heidelberg (Germany); Leibniz Institute for Solid State and Materials Research (IFW) Dresden (Germany); Hampel, S.; Leonhardt, A.; Khavrus, V.; Buechner, B. [Leibniz Institute for Solid State and Materials Research (IFW) Dresden (Germany); Klingeler, R. [Kirchhoff Institute for Physics, University of Heidelberg, D-69120 Heidelberg (Germany)

    2011-07-01

    Controlled synthesis of magnetic nanoparticles with well-defined size and composition is always a challenge in material-based nanoscience. Here, we apply the high pressure chemical vapour deposition technique (HPCVD) to obtain carbon-shielded magnetic alloy nanoparticles under control of the particle size. Carbon encapsulated NiPt, CoPt (NiPt rate at C, CoPt rate at C) nanoalloys were synthesized by means of HPCVD starting from sublimating appropriate metal-organic precursors. Structural characterization by means of high resolution transmission electron microscopy, energy dispersive X-ray analysis and X-ray diffraction indicated the formation of coated bimetallic Ni{sub x}Pt{sub 100-x} and CoxPt{sub 100-x} nanoparticles. Adjusting the sublimation temperature of the different precursors allowed tuning the core sizes with small size distribution. In addition, detailed studies of the magnetic properties are presented. AC magnetic heating studies imply the potential of the coated nanoalloys for hyperthermia therapy.

  13. Adsorption and oxidation of acetaldehyde on carbon supported Pt, PtSn and PtSn-based trimetallic catalysts by in situ Fourier transform infrared spectroscopy

    Beyhan, Seden; Léger, Jean-Michel; Kadırgan, Figen

    2013-11-01

    The adsorption and oxidation of acetaldehyde on carbon supported Pt, Pt90Sn10 and Pt80Sn10M10 (M = Ni, Co, Rh, Pd) catalysts have been investigated by using in situ Fourier transform infrared (FTIR) spectroscopy. The result revealed that Pt90Sn10/C catalyst is not very efficient for the conversion of acetaldehyde to CO2 due to the weak adsorption of acetaldehyde in the presence of Sn. However, the addition of a third metal to Pt--Sn facilitates the C-C bond cleavage of acetaldehyde. It seems that acetaldehyde is adsorbed dissociatively on the surface of Pt80Sn10Ni10/C, Pt80Sn10Co10/C, Pt80Sn10Rh10/C catalysts, producing CH3 and CHO adsorbate species, which can be further oxidized to CO2. However, the pathway forming CO2 for Pt80Sn10Pd10/C catalyst mainly originates from the oxidation of CH3CO species. Thus, the presence of third metal in the PtSn catalyst has a strong impact upon the acetaldehyde adsorption behaviour and its reaction products.

  14. DSC study of martensite transformation in TiPt alloys

    Chikosha, S

    2012-09-01

    Full Text Available Conclusions drawn from this presentation were that when SPS, HP and Press and Sinter methods were used to form TiPt phase from elemental Ti and Pt powders, Press and Sinter was less successful. Presence of Ti-rich and Pt-rich phases coexisting...

  15. Preparation of Pt Nanocatalyst on Carbon Materials via a Reduction Reaction of a Pt Precursor in a Drying Process.

    Lee, Jae-Young; Lee, Woo-Kum; Rim, Hyung-Ryul; Joung, Gyu-Bum; Weidner, John W; Lee, Hong-Ki

    2016-06-01

    Platinum (Pt) nanocatalyst for a proton-exchange membrane fuel cell (PEMFC) was prepared on a carbon black particle or a graphite particle coated with a nafion polymer via a reduction of platinum(II) bis(acetylacetonate) denoted as Pt(acac)2 as a Pt precursor in a drying process. Sublimed Pt(acac)2 adsorbed on the nafion-coated carbon materials was reduced to Pt nanoparticles in a glass reactor at 180 degrees C of N2 atmosphere. The morphology of Pt nanoparticles on carbon materials was observed by scanning electron microscopy (SEM) and the distribution of Pt nanoparticles was done by transmission electron microscopy (TEM). The particle size was estimated by analyzing the TEM image using an image analyzer. It was found that nano-sized Pt particles were deposited on the surface of carbon materials, and the number density and the average particle size increased with increasing reduction time.

  16. Machine for compacting solid residues

    Herzog, J.

    1981-11-01

    Machine for compacting solid residues, particularly bulky radioactive residues, constituted of a horizontally actuated punch and a fixed compression anvil, in which the residues are first compacted horizontally and then vertically. Its salient characteristic is that the punch and the compression anvil have embossments on the compression side and interpenetrating plates in the compression position [fr

  17. Quadratic residues and non-residues selected topics

    Wright, Steve

    2016-01-01

    This book offers an account of the classical theory of quadratic residues and non-residues with the goal of using that theory as a lens through which to view the development of some of the fundamental methods employed in modern elementary, algebraic, and analytic number theory. The first three chapters present some basic facts and the history of quadratic residues and non-residues and discuss various proofs of the Law of Quadratic Reciprosity in depth, with an emphasis on the six proofs that Gauss published. The remaining seven chapters explore some interesting applications of the Law of Quadratic Reciprocity, prove some results concerning the distribution and arithmetic structure of quadratic residues and non-residues, provide a detailed proof of Dirichlet’s Class-Number Formula, and discuss the question of whether quadratic residues are randomly distributed. The text is a valuable resource for graduate and advanced undergraduate students as well as for mathematicians interested in number theory.

  18. Role of Pt(0) in bimetallic (Pt,Fe)-FER catalysts in the N2O decomposition

    Tabor, Edyta; Jíša, Kamil; Nováková, Jana; Bastl, Zdeněk; Vondrová, Alena; Závěta, K.; Sobalík, Zdeněk

    2013-01-01

    Roč. 165, JAN 2013 (2013), s. 40-47 ISSN 1387-1811 R&D Projects: GA ČR GA203/09/1627 Institutional support: RVO:61388955 Keywords : bimetallic Pt,Fe- FER * Pt- FER * Pt(0) clusters Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.209, year: 2013

  19. Electrocatalytic oxidation of methanol on (Pb) lead modified by Pt, Pt-Ru and Pt-Sn microparticles dispersed into poly(o-phenylenediamine) film

    Golikand, Ahmad Nozad; Maragheh, Mohammad Ghannadi; Irannejad, Leila [Jaber Ibn Hayan Research Lab., Atomic Energy Organization of Iran (AEOI), Tehran (Iran); Golabi, Seyed Mehdi [Electroanalytical Chemistry Lab., Faculty of Chemistry, University of Tabriz, Tabriz (Iran)

    2005-08-18

    The electrocatalytic oxidation of methanol at a (Pb) lead electrode modified by Pt, Pt-Ru and Pt-Sn microparticles dispersed into poly(o-phenylenediamine) (PoPD) film has been investigated using cyclic voltammetry as analytical technique and 0.5M sulfuric acid as supporting electrolyte. It has been shown that the presence of PoPD film increases considerably the efficiency of deposited Pt and Pt alloys microparticles toward the electrocatalytic oxidation of methanol. The catalytic activity of Pt particles is further enhanced when Ru and especially Sn, is co-deposited in the polymer film. The effects of various parameters such as concentration of methanol, medium temperature as well as the long term stability of modified electrodes have also been investigated. (author)

  20. Hydrophilic Pt nanoflowers: synthesis, crystallographic analysis and catalytic performance.

    Mourdikoudis, Stefanos; Altantzis, Thomas; Liz-Marzán, Luis M; Bals, Sara; Pastoriza-Santos, Isabel; Pérez-Juste, Jorge

    2016-05-21

    Water-soluble Pt nanoflowers (NFs) were prepared by diethylene glycol-mediated reduction of Pt acetylacetonate (Pt(acac) 2 ) in the presence of polyethylenimine. Advanced electron microscopy analysis showed that the NFs consist of multiple branches with a truncated cubic morphology and different crystallographic orientations. We demonstrate that the nature of the solvent strongly influences the resulting morphology. The catalytic performance of the Pt NFs in 4-nitrophenol reduction was found to be superior to that of other nanoparticle-based catalysts. Additionally, the Pt NFs display good catalytic reusability with no loss of activity after five consecutive cycles.

  1. Determination of intrinsic spin Hall angle in Pt

    Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 117576 (Singapore)

    2014-10-13

    The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.

  2. Determination of intrinsic spin Hall angle in Pt

    Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo

    2014-01-01

    The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.

  3. 40 CFR Appendix Vii to Part 266 - Health-Based Limits for Exclusion of Waste-Derived Residues*

    2010-07-01

    ... Waste-Derived Residues* VII Appendix VII to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES AND SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES Pt. 266, App. VII Appendix VII to Part 266—Health...

  4. Sonochemical synthesis and characterization of Pt/CNT, Pt/TiO2, and Pt/CNT/TiO2 electrocatalysts for methanol electro-oxidation

    Bedolla-Valdez, Z.I.; Verde-Gómez, Y.; Valenzuela-Muñiz, A.M.; Gochi-Ponce, Y.; Oropeza-Guzmán, M.T.; Berhault, Gilles; Alonso-Núñez, G.

    2015-01-01

    Highlights: • Pt/CNT/TiO 2 electrocatalyst was successfully prepared by the sonochemical method. • The electrocatalyst Pt/CNT/TiO 2 was synthesized without heat treatments, additives or surfactants. • The TiO 2 -Pt interaction improves the CO-tolerance of Pt/CNT/TiO 2 , as well as the electrocatalyst stability. • Low amount of multi-walled carbon nanotubes increases the current density of Pt/CNT/TiO 2 significantly compared to Pt/TiO 2 . - Abstract: Pt electrocatalyst supported on composite formed of multi-walled carbon nanotubes and titanium oxide (CNT/TiO 2 ) was successfully synthesized by a sonochemical method without heat treatments, surfactants or additives. This electrocatalyst could be used for direct methanol fuel cells (DMFC) applications. For comparison, Pt/CNT and Pt/TiO 2 electrocatalysts were prepared as reference samples. Structural properties and morphology of the synthesized materials were examined by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and their specific surface areas were determined by the Brunauer-Emmett-Teller method. The Pt and acid-treated CNT contents were analyzed by inductively coupled plasma atomic emission spectroscopy and thermogravimetric analysis, respectively. The electrochemical properties of the synthesized electrocatalysts were evaluated by cyclic voltammetry (CV) and chronoamperometry in a three-electrode cell at room temperature. The evaluation performed using electrochemical techniques suggests that TiO 2 promotes the CO-tolerance due to TiO 2 -Pt interaction. The CV tests demonstrated that 6 wt.% of acid-treated CNT increases significantly the current density when Pt selectively interacts with TiO 2 .

  5. Half-Lantern Pt(II and Pt(III Complexes. New Cyclometalated Platinum Derivatives

    Violeta Sicilia

    2014-08-01

    Full Text Available The divalent complex [{Pt(bzq(μ-L}2] (1 [Hbzq = benzo[h]quinolone, HL = CF3C4H2N2SH: 4-(trifluoromethylpyrimidine-2-thiol] was obtained from equimolar amounts of [Pt(bzq(NCMe2]ClO4 and 4-(trifluoromethylpyrimidine-2-thiol with an excess of NEt3. The presence of a low intensity absorption band at 486 nm (CH2Cl2, assignable to a metal-metal-to-ligand charge transfer transition (1MMLCT [dσ*(Pt2→π*(bzq], is indicative of the existence of two platinum centers located in close proximity because the rigidity of the half-lantern structure allows the preservation of these interactions in solution. Compound 1 undergoes two-electron oxidation upon treatment with halogens X2 (X2: Cl2, Br2 or I2 to give the corresponding dihalodiplatinum (III complexes [{Pt(bzq(μ-LX}2] (L = CF3C4H2N2S-κN,S; X: Cl 2, Br 3, I 4. Complexes 2–4 were also obtained by reaction of 1 with HX (molar ratio 1:2, 10% excess of HX in THF with yields of about 80% and compound 2 was also obtained by reaction of [{Pt(bzq(μ-Cl}2] with HL (4-(trifluoromethylpyrimidine-2-thiol in molar ratio 1:2 in THF, although in small yield. The X-ray structures of 2 and 3 confirmed the half-lantern structure and the anti configuration of the molecules. Both of them show Pt–Pt distances (2.61188(15 Å 2, 2.61767(16 Å 3 in the low range of those observed in Pt2(III,IIIX2 half-lantern complexes.

  6. Transforming AdaPT to Ada

    Goldsack, Stephen J.; Holzbach-Valero, A. A.; Waldrop, Raymond S.; Volz, Richard A.

    1991-01-01

    This paper describes how the main features of the proposed Ada language extensions intended to support distribution, and offered as possible solutions for Ada9X can be implemented by transformation into standard Ada83. We start by summarizing the features proposed in a paper (Gargaro et al, 1990) which constitutes the definition of the extensions. For convenience we have called the language in its modified form AdaPT which might be interpreted as Ada with partitions. These features were carefully chosen to provide support for the construction of executable modules for execution in nodes of a network of loosely coupled computers, but flexibly configurable for different network architectures and for recovery following failure, or adapting to mode changes. The intention in their design was to provide extensions which would not impact adversely on the normal use of Ada, and would fit well in style and feel with the existing standard. We begin by summarizing the features introduced in AdaPT.

  7. Evaluasi Sistem Informasi Penjualan PT SPNS

    Anderes Gui

    2010-06-01

    Full Text Available The purpose of this paper is to identify and analyze problems that occur in information systems sales PT SPNS. It also serves to control the management and control of applications running well so it can produce accurate information for decision making. The method used is book study method and field study. Study was done by reading library books, scientific papers and other sources, while the field study was done by observation, interviews, and questionnaires. The result of the evaluation is derived from the respective strengths and weaknesses - each control. Weaknesses are found, the findings presented in the form of a matrix that contains the findings and recommendations as a matter of risk remedial action. Conclusions obtained from the audit for security control, operations, limitations, input and output is good enough because it can satisfy and support the sales activities of PT SPNS.

  8. Revisiting the Optical PT-Symmetric Dimer

    José Delfino Huerta Morales

    2016-08-01

    Full Text Available Optics has proved a fertile ground for the experimental simulation of quantum mechanics. Most recently, optical realizations of PT -symmetric quantum mechanics have been shown, both theoretically and experimentally, opening the door to international efforts aiming at the design of practical optical devices exploiting this symmetry. Here, we focus on the optical PT -symmetric dimer, a two-waveguide coupler where the materials show symmetric effective gain and loss, and provide a review of the linear and nonlinear optical realizations from a symmetry-based point of view. We go beyond a simple review of the literature and show that the dimer is just the smallest of a class of planar N-waveguide couplers that are the optical realization of the Lorentz group in 2 + 1 dimensions. Furthermore, we provide a formulation to describe light propagation through waveguide couplers described by non-Hermitian mode coupling matrices based on a non-Hermitian generalization of the Ehrenfest theorem.

  9. CoPt nanoparticles by chemical reduction

    Wang, H.L.; Zhang, Y.; Huang, Y.; Zeng, Q.; Hadjipanayis, G.C.

    2004-01-01

    CoPt nanoparticles with a size of 1-2 nm were synthesized by chemical reduction using the solvents of water and alcohol. A phase transformation from the originally disordered face centered cubic (FCC) structure to an ordered face centered tetragonal L1 0 structure occurred after annealing, which results in the coercivity up to 9 kOe because of the high anisotropy of the tetragonal phase (K∼2-4x10 7 erg/cm 3 ) (Philos. Mag. 13 (1966) 567; IEEE Trans. Magn. 20 (1984) 1625). HREM images of as-grow Co 48 Pt 52 shows the single-crystalline FCC structure with the shape of columnar and spherical

  10. Role of rotational energy component in the dynamics of 16O+198Pt reaction

    Sharma Manoj K.

    2017-01-01

    Full Text Available The role of rotational energy is investigated in reference to the dynamics of 16O+198Pt →214Rn∗ reaction using the sticking (IS and the non-sticking (INS limits of moment of inertia within the framework of dynamical cluster decay model. The decay barrier height and barrier position get significantly modified for the use of sticking or non-sticking choice, which in turn reproduce the evaporation residue and the fusion-fission cross-sections nicely by the IS approach, while the INS approach provides feasible addressal of data only for evaporation residue channel. Moreover, the fragmentation path of decaying fragments of 214Rn∗ compound nucleus gets influenced for different choices of moment of inertia. Beside this, the role of nuclear deformations i.e. static, dynamic quadurpole (β2 and higher order static deformation up to β4 are duly investigated for both choices of the moment of inertia.

  11. Pt based anode catalysts for direct ethanol fuel cells

    Zhou, Weijiang; Zhou, Zhenhua; Song, Shuqin; Li, Wenzhen; Sun, Gongquan; Xin, Qin [Direct Alcohol Fuel Cell Laboratory, Dalian Institute of Chemical Physics, CAS, P.O. Box 110, Dalian 116023 (China); Tsiakaras, Panagiotis [Department of Mechanical and Industrial Engineering, University of Thessalia, Pedion Areos, GR 38334 Volos (Greece) 7

    2003-11-10

    In the present work several Pt-based anode catalysts supported on carbon XC-72R were prepared with a novel method and characterized by means of XRD, TEM and XPS analysis. It was found that all these catalysts are consisted of uniform nanosized particles with sharp distribution and Pt lattice parameter decreases with the addition of Ru or Pd and increases with the addition of Sn or W. Cyclic voltammetry (CV) measurements and single direct ethanol fuel cell (DEFC) tests jointly showed that the presence of Sn, Ru and W enhances the activity of Pt towards ethanol electro-oxidation in the following order: Pt{sub 1}Sn{sub 1}/C>Pt{sub 1}Ru{sub 1}/C>Pt{sub 1}W{sub 1}/C>Pt{sub 1}Pd{sub 1}/C>Pt/C. Moreover, Pt{sub 1}Ru{sub 1}/C further modified by W and Mo showed improved ethanol electro-oxidation activity, but its DEFC performance was found to be inferior to that measured for Pt{sub 1}Sn{sub 1}/C. Under this respect, several PtSn/C catalysts with different Pt/Sn atomic ratio were also identically prepared and characterized and their direct ethanol fuel cell performances were evaluated. It was found that the single direct ethanol fuel cell having Pt{sub 1}Sn{sub 1}/C or Pt{sub 3}Sn{sub 2}/C or Pt{sub 2}Sn{sub 1}/C as anode catalyst showed better performances than those with Pt{sub 3}Sn{sub 1}/C or Pt{sub 4}Sn{sub 1}/C. It was also found that the latter two cells exhibited higher performances than the single cell using Pt{sub 1}Ru{sub 1}/C, which is exclusively used in PEMFC as anode catalyst for both methanol electro-oxidation and CO-tolerance. This distinct difference in DEFC performance between the catalysts examined here would be attributed to the so-called bifunctional mechanism and to the electronic interaction between Pt and additives. It is thought that an amount of -OH{sub ads}, an amount of surface Pt active sites and the conductivity effect of PtSn/C catalysts would determine the activity of PtSn/C with different Pt/Sn ratios. At lower temperature values or at low

  12. Bioenergy from sisal residues

    Jungersen, G. [Dansk Teknologisk Inst. (Denmark); Kivaisi, A.; Rubindamayugi, M. [Univ. of Dar es Salaam (Tanzania, United Republic of)

    1998-05-01

    The main objectives of this report are: To analyse the bioenergy potential of the Tanzanian agro-industries, with special emphasis on the Sisal industry, the largest producer of agro-industrial residues in Tanzania; and to upgrade the human capacity and research potential of the Applied Microbiology Unit at the University of Dar es Salaam, in order to ensure a scientific and technological support for future operation and implementation of biogas facilities and anaerobic water treatment systems. The experimental work on sisal residues contains the following issues: Optimal reactor set-up and performance; Pre-treatment methods for treatment of fibre fraction in order to increase the methane yield; Evaluation of the requirement for nutrient addition; Evaluation of the potential for bioethanol production from sisal bulbs. The processing of sisal leaves into dry fibres (decortication) has traditionally been done by the wet processing method, which consumes considerable quantities of water and produces large quantities of waste water. The Tanzania Sisal Authority (TSA) is now developing a dry decortication method, which consumes less water and produces a waste product with 12-15% TS, which is feasible for treatment in CSTR systems (Continously Stirred Tank Reactors). (EG)

  13. First principles study of (Cd, Hg, In, Tl, Sn, Pb, As, Sb, Bi, Se) modified Pt(111), Pt(100) and Pt(211) electrodes as CO oxidation catalysts

    Tripkovic, Vladimir

    2015-01-01

    . The coverage dependence as a function of potential for ten different adatom species (Cd, Hg, In, Tl, Sn, Pb, As, Sb, Bi, Se) on bare and CO saturated Pt(111), Pt(100) and Pt(211) surfaces has been established by means of Density Functional Theory calculations. Most of the adatoms are very stable under standard......, given by the OH formation potentials from water, is dependent on the oxophilicity of the adatoms, and is found to scale almost inversely with the adatom stability. In electrolyte solutions saturated with CO, the stability reduces to roughly half of that on bare Pt surfaces. Irrespective of the CO...

  14. Study of transition probabilities in 192Pt

    Roulet, C.; Sergolle, H.; Hubert, P.P.; Lindblad, T.

    1978-01-01

    The nucleus 192 Pt is Coulomb excited with 370 MeV 84 Kr projectiles. Levels up to spin 8 + (10 + ) in the ground band and up to 6 + in the γ-band are observed. The B(E2) values implied by the observed yields are compared with predictions of different nuclear models. Particular attention is paid to the ground band transition rates and the rotation-alignment model

  15. Methanol electro-oxidation and direct methanol fuel cell using Pt/Rh and Pt/Ru/Rh alloy catalysts

    Choi, Jong-Ho; Park, Kyung-Won; Park, In-Su; Nam, Woo-Hyun; Sung, Yung-Eun

    2004-01-01

    Pt-based binary or ternary catalysts containing Rh for use as anodes in direct methanol fuel cells (DMFC) were synthesized by borohydride reduction method combined with freeze-drying. The resulting catalysts had a specific surface area of approximately 65-75 m 2 /g. X-ray diffraction (XRD) patterns indicated that the catalysts were well alloyed and the average size of alloy catalysts was confirmed by transmission electron microscopy (TEM). The Pt/Rh (2:1) and Pt/Ru/Rh (5:4:1) alloy catalysts showed better catalytic activities for methanol electro-oxidation than Pt or Pt/Ru (1:1), respectively

  16. Longitudinal recording on FePt and FePtX (X = B, Ni) intermetallic compounds

    Li, Ning

    1999-11-01

    Near field recording on high coercivity FePt intermetallic compound media using a high Bsat write element was investigated. Untextured FePt media were prepared by magnetron sputtering on ZrO2 disks at a substrate temperature of 450°C, with post annealing at 450°C for 8 hrs. Both multilayer and cosputtered precursors produced the ordered tetragonal L10 phase with high coercivity between 5kOe and 12kOe. To improve readback noise decrease magnetic domain size, FePtB media were subsequently prepared by cosputtering. Over-write, roll-off, signal to noise ratio and non-linear transition shift (NLTS) ere measured by both metal in gap (MIG) and merged MR heads. FePtB media showed similar NLTS to commercial CoCrPtTa longitudinal media, but 5dB lower signal to noise ratio. By operating recording transducers in near contact, reasonable values of (>30dB) could be obtained. VSM Rotational Transverse Magnetization has been used for measuring the anisotropy field of magnetic thin films. Magnetization reversal during rotation of a 2D isotropic an applied field is discussed. The relationship between the transverse magnetization My and the applied field H was numerically solved. An excellent approximation for the transverse magnetization is found to be: My/Ms=A(1- H/Hk) 2.5, where A = 1.1434, and Hk is the anisotropy field. For curve fitting to experimental data, both A and Hk were used as fitting parameters. Comparison between a constructed torque hysteresis method and this VSM RTM method have been made theoretically and experimentally. Both results showed that VSM RTM will give better extrapolation of the anisotropy field. The torque measurement will slightly overestimate the anisotropy field. The anisotropy fields of FePt and FePtX (X = B, Ni) films were characterized using this VSM RTM technique with comparison to a CoCrTaPt disk. Anisotropy energy was derived. Hc/Hk was used as an indicator for coherent rotation of a single domain. Interactions between magnetic domains were

  17. Kinetic study of methanol oxidation on carbon-supported PtRu electrocatalyst

    Gojkovic, S.Lj.; Vidakovic, T.R.; Durovic, D.R.

    2003-01-01

    Methanol electrooxidation was investigated on the carbon-supported PtRu electrocatalyst (1:1 atomic ratio) in acid media. X-ray diffraction measurement indicated alloying of Pt and Ru. Cyclic voltammetry of the sample reflects the amount of Ru in the catalyst and its ability to adsorb OH radicals. Tafel plots for the oxidation of 0.02-3 M methanol in the solutions containing 0.05-1 M HClO 4 and in the temperature range 27-40 deg. C showed reasonably well-defined linear region with the slope of about 115 mV dec -1 at the low currents, irrespective of the experimental conditions employed. Reaction order with respect to methanol was found to be 0.5. A correlation between methanol oxidation rate and pseudocapacitive current of OH adsorption on Ru sites was established. It was proposed that bifunctional mechanism is operative with the reaction between methanol residues adsorbed on Pt sites and OH radicals adsorbed on Ru sites as the rate-determining step

  18. Characteristics of ferroelectric Pb(Zr,Ti)O3 thin films having Pt/PtOx electrode barriers

    Lee, Kwangbae; Rhee, Byung Roh; Lee, Chanku

    2001-01-01

    We have investigated the feasibility of the Pt/PtO x multilayer as an electrode barrier for Pb(Zr,Ti)O 3 (PZT)-based ferroelectric random access memories. PtO x and Pt layers were prepared on polycrystalline-Si/SiO 2 /Si substrates by means of the sputtering method in Ar and O 2 ambience, and the Pb(Zr 0.53 Ti 0.47 )O 3 layer was prepared by the sol-gel method. A capacitor consisting of Pt/PtO x /PZT/PtO x /Pt/PtO x /poly-Si had a remanent polarization of 18 μC/cm 2 and a low coercive field of 32 kV/cm. The polarization fatigue behavior of test capacitors was improved as compared with that of Pt/PZT/Pt, which showed negligible fatigue loss of 15% after 10 11 switching repetitions with a frequency of 1 MHz. Copyright 2001 American Institute of Physics

  19. Kinetic Investigation of Homogeneous H(2)-D(2) Equilibration Catalyzed by Pt-Au Cluster Compounds. Characterization of the Cluster [(H)Pt(AuPPh(3))(9)](NO(3))(2).

    Rubinstein, Leon I.; Pignolet, Louis H.

    1996-11-06

    The new Pt-Au hydrido cluster compound [(H)Pt(AuPPh(3))(9)](NO(3))(2) (3) has been synthesized and characterized by NMR, FABMS, and single-crystal X-ray diffraction [triclinic, P&onemacr;, a = 17.0452(1) Å, b = 17.4045(2) Å, c = 55.2353(1) Å, alpha = 89.891(1) degrees, beta = 85.287(1) degrees, gamma = 75.173(1) degrees, V = 15784.0(2) Å(3), Z = 4 (two molecules in asymmetric unit), residual R = 0.089 for 45 929 observed reflections and 3367 variables, Mo Kalpha radiation]. The Pt(AuP)(9) core geometry is a distorted icosahedron with three vertices vacant. The Pt-Au, Au-Au, and Au-P distances are within the normal ranges observed in other Pt-Au clusters. This cluster is a catalyst for H(2)-D(2) equilibration in homogeneous solution phase and has been used in a general mechanistic study of this reaction catalyzed by Pt-Au clusters. We previously proposed that a key step in the mechanism for catalytic H(2)-D(2) equilibration is the dissociation of a PPh(3) ligand to give a cluster with an open Au site for bonding of H(2) or D(2). This was based on qualitative observations that PPh(3) inhibited the rate of HD production with [Pt(AuPPh(3))(8)](NO(3))(2) (1) as catalyst. In order to test this hypothesis, phosphine inhibition (on the rate of HD production) and phosphine ligand exchange kinetic experiments were carried out with [(H)(PPh(3))Pt(AuPPh(3))(7)](NO(3))(2) (2) and 3. In this paper we show that the rate constant for phosphine dissociation determined from the PPh(3) inhibition rate study of H(2)-D(2) equilibration with cluster 2 is nearly identical to the rate constant for dissociative phosphine ligand exchange. The slower rate for H(2)-D(2) equilibration observed with 3 compared with 2 (5.5 x 10(-3) vs 7.7 x 10(-2) turnover s(-1)) is explained by its smaller rate constant for phosphine dissociation (2.8 x 10(-5) vs 2.9 x 10(-4) s(-1)). The fact that clusters 2 and 3 show similar kinetic behaviors suggests that the PPh(3) dissociation step in the catalytic H(2

  20. Lemna minor tolerance to metal-working fluid residues: implications for rhizoremediation.

    Grijalbo, L; Becerril, J M; Barrutia, O; Gutierrez-Mañero, J; Lucas Garcia, J A

    2016-07-01

    For the first time in the literature, duckweed (Lemna minor) tolerance (alone or in combination with a consortium of bacteria) to spent metal-working fluid (MWF) was assessed, together with its capacity to reduce the chemical oxygen demand (COD) of this residue. In a preliminary study, L. minor response to pre-treated MWF residue (ptMWF) and vacuum-distilled MWF water (MWFw) was tested. Plants were able to grow in both residues at different COD levels tested (up to 2300 mg·l(-1) ), showing few toxicity symptoms (mainly growth inhibition). Plant response to MWFw was more regular and dose responsive than when exposed to ptMWF. Moreover, COD reduction was less significant in ptMWF. Thus, based on these preliminary results, a second study was conducted using MWFw to test the effectiveness of inoculation with a bacterial consortium isolated from a membrane bioreactor fed with the same residue. After 5 days of exposure, COD in solutions containing inoculated plants was significantly lower than in non-inoculated ones. Moreover, inoculation reduced β+γ-tocopherol levels in MWFw-exposed plants, suggesting pollutant imposed stress was reduced. We therefore conclude from that L. minor is highly tolerant to spent MWF residues and that this species can be very useful, together with the appropriate bacterial consortium, in reducing COD of this residue under local legislation limits and thus minimise its potential environmental impact. Interestingly, the lipophilic antioxidant tocopherol (especially the sum of β+γ isomers) proved to be an effective plant biomarker of pollution. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  1. Comparison of PZN-PT, PMN-PT single crystals and PZT ceramic for vibration energy harvesting

    Yang, Zhengbao; Zu, Jean

    2016-01-01

    Highlights: • Systematic analysis of PMN-PT and PZN-PT single crystals for energy harvesters. • Performance analysis and comparison under various conditions. • Discussion of the effect of the SSHI technique on single crystal energy harvesters. • Efficiency analysis in both on-resonance and off-resonance conditions. - Abstract: Vibration energy harvesting has a great potential to achieve self-powered operations for wireless sensors, wearable devices and medical electronics, and thus has attracted much attention in academia and industry. The majority of research into this subject has focused on the piezoelectric effect of synthetic materials, especially the perovskite PZT ceramics. Recently the new-generation piezoelectric materials PMN-PT and PZN-PT single crystals have gained significant interest because of their outstanding piezoelectric properties. They can be used to replace the widely-adopted PZT ceramics for improving energy harvesters’ performance substantially. However, there is little research on comparing PMN-PT and PZN-PT energy harvesters against PZT harvesters. In this paper, we present a systematic comparison between vibration energy harvesters using the PMN-PT, PZN-PT single crystals and those using the PZT ceramics. Key properties of the three materials are summarized and compared. The performance of the PMN-PT and PZN-PT energy harvesters is characterized under different conditions (beam length, resistance, frequency, excitation strength, and backward coupling effect), and is quantitatively compared with the PZT counterpart. Furthermore, the effect of the synchronized switch harvesting on inductor (SSHI) circuit on the three harvesters is discussed. The experimental results indicate that energy harvesters using the PMN-PT and PZN-PT single crystals can significantly outperform those using the PZT ceramics. This study provides a strong base for future research on high-performance energy harvesters using the new PMN-PT and PZN-PT single

  2. Electrochemical Synthesis of Ammonia from Water and Nitrogen using a Pt/GDC/Pt Cell

    Kim, Jong Nam; Yoo, Chung-Yul; Joo, Jong Hoon; Yu, Ji Haeng; Sharma, Monika; Yoon, Hyung Chul; Jeoung, Hana; Song, Ki Chang

    2014-01-01

    Electrochemical ammonia synthesis from water and nitrogen using a Pt/GDC/Pt cell was experimentally investigated. Electrochemical analysis and ammonia synthesis in the moisture-saturated nitrogen environment were performed under the operating temperature range 400-600 .deg. C and the applied potential range OCV (Open Circuit Voltage)-1.2V. Even though the ammonia synthesis rate was augmented with the increase in the operating temperature (i.e.. increase in the applied current) under the constant potential, the faradaic efficiency was decreased because of the limitation of dissociative chemisorption of nitrogen on the Pt electrode. The maximum synthesis rate of ammonia was 3.67x10 -11 mols -1 cm -2 with 0.1% faradaic efficiency at 600 .deg. C

  3. Electrochemical Synthesis of Ammonia from Water and Nitrogen using a Pt/GDC/Pt Cell

    Kim, Jong Nam; Yoo, Chung-Yul; Joo, Jong Hoon; Yu, Ji Haeng; Sharma, Monika; Yoon, Hyung Chul [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Jeoung, Hana; Song, Ki Chang [Konyang University, Nonsan (Korea, Republic of)

    2014-02-15

    Electrochemical ammonia synthesis from water and nitrogen using a Pt/GDC/Pt cell was experimentally investigated. Electrochemical analysis and ammonia synthesis in the moisture-saturated nitrogen environment were performed under the operating temperature range 400-600 .deg. C and the applied potential range OCV (Open Circuit Voltage)-1.2V. Even though the ammonia synthesis rate was augmented with the increase in the operating temperature (i.e.. increase in the applied current) under the constant potential, the faradaic efficiency was decreased because of the limitation of dissociative chemisorption of nitrogen on the Pt electrode. The maximum synthesis rate of ammonia was 3.67x10{sup -11} mols{sup -1}cm{sup -2} with 0.1% faradaic efficiency at 600 .deg. C.

  4. Magnetic and electronic properties of a Pt-Co bilayer on Pt(1 1 1)

    Giovanelli, L.; De Santis, M.; Panaccione, G.; Sirotti, F.; Torelli, P.; Vobornik, I.; Larcipretea, R.; Egger, S.; Saint-Lager, M.C.; Dolle, P.; Rossi, G.

    2005-01-01

    Atomically thin Co/Pt(1 1 1) interfaces grown at different temperatures are characterized by very different values of perpendicular magnetic anisotropy as a consequence of the local structure and coordination. Here we present a study of the structural, magnetic and electronic properties for interfaces grown in UHV onto clean Pt(1 1 1) in different kinetic conditions. When one monolayer of Co is deposited at 540 K a thermally activated exchange reaction leads to a sharp Pt-Co double interface giving rise to a strong increase of the magneto-optical response with respect to the Co monolayer deposited at room temperature. The results are interpreted in terms of atomic hybridization as detected by valence band photoelectron spectroscopy

  5. Fischer-Tropsch synthesis: study of the promotion of Pt on the reduction property of Co/Al2O3 catalysts by in situ EXAFS of Co K and Pt LIII edges and XPS

    Jacobs, G.; Chaney, J.A.; Patterson, P.M.; Das, T.K.; Maillot, J.C.; Davis, B.H.

    2004-01-01

    The addition of platinum metal to cobalt/alumina-based Fischer-Tropsch synthesis (FTS) catalysts increases both the reduction rate and, consequently, the density of active cobalt sites. Platinum also lowers the temperature of the two-step conversion of cobalt oxide to cobalt metal observed in temperature programmed reduction (TPR) as Co 3 O 4 to CoO and CoO to Co 0 . The interaction of the alumina support with cobalt oxide ultimately determines the active site density of the catalyst surface. This interaction can be controlled by varying the cobalt loading and dispersion, selecting supports with differing surface areas or pore sizes, or changing the noble metal promoter. However, the active site density is observed to depend primarily on the cluster size and extent of reduction, and there is a direct relationship between site density and FTS rate. In this work, in situ extended X-ray absorption fine structure (EXAFS) at the L III edge of Pt was used to show that isolated Pt atoms interact with supported cobalt clusters without forming observable Pt-Pt bonds. K-edge EXAFS was also used to verify that the cobalt cluster size increases slightly for those systems with Pt promotion. X-ray absorption near-edge spectroscopy (XANES) was used to examine the remaining cobalt clusters after the first stage of TPR, and it revealed that the species were almost entirely cobalt (II) oxide. After the second stage of TPR to form cobalt metal, a residual oxide persists in the sample, and this oxide has been identified as cobalt (II) aluminate using X-ray photoelectron spectroscopy (XPS). Sequential in situ reduction of promoted and unpromoted systems was also monitored through XPS, and Pt was seen to increase the extent of cobalt reduction by a factor of two. (orig.)

  6. Bimetallic Ag-Pt and Au-Pt aggregates synthesized by radiolysis

    Remita, S.; Mostafavi, M.; Delcourt, M.O.

    1996-01-01

    Irradiating aqueous solutions containing both Ag 2 So 4 and K 2 PtCl 4 leads to intermetallic aggregates of various sizes according to the stabilizing agent: polyvinylalcohol, polyacrylic acid or polyacrylate. In the last case, the particle diameter is 1.5 nm. The bimetallic character is evidenced in all cases by the spectral changes of such sols compared to pure silver sols which display a characteristic surface plasmon absorption band. This plasmon band disappears when 10 to 20 at.% or more Pr is present. Observation by TEM gives an estimation of the particle sizes. Comparable results have been obtained for Au-Pt particles. (author)

  7. Residual effect of sugar cane ratoon of urea nitrogen foliar application to plant cane

    Trivelin, P.C.O.; Lara Cabezas, W.A.R.; Coleti, J.T.

    1984-01-01

    The residual effect of urea - N, foliar applied to plant cane, on sugar cane ratoon is studied. Setts grown in drums containing washed sand are used. 180 days from planting, foliar fertilizer (43.5% urea solution) labelled with 3.95 atom % 15 N is applied. The first harvest is made 7 days after application and final harvest of resprouting at 123 days. (M.A.C.) [pt

  8. Residual strain in the Nb-H system measured by selected area diffraction (SAD)

    Bulhoes, I.A.M.; Akune, K.; Pinatti, Dyonisio G.

    1981-07-01

    Various specimens of Nb were annealed in vacuum of 10 -3 torr for four hours at 1770 0 K. These speciments were doped with hydrogen up to 1000 ppm by weight and then were analyzed selected area diffraction. The line resolution of the electron channelling pattern was meassured for the specimens with different hydrogen content. These measurements, combined with the measurement of density, permitted one to estimate the residual strain caused by hydrogen. (Author) [pt

  9. Engineering the Activity and Stability of Pt-Alloy Cathode Fuel-Cell Electrocatalysts by Tuning the Pt-Pt Distance

    Escribano, Maria Escudero; Malacrida, Paolo; Vej-Hansen, Ulrik Grønbjerg

    2014-01-01

    for enhancing the cathode activity is to alloy Pt with transition metals [1-2]. However, alloys of Pt and late transition metals are typically unstable under fuel-cell conditions. Herein, we present experimental and theoretical studies showing the trends in activity and stability of novel cathode catalysts...

  10. Immobilization of acid digestion residue

    Greenhalgh, W.O.; Allen, C.R.

    1983-01-01

    Acid digestion treatment of nuclear waste is similar to incineration processes and results in the bulk of the waste being reduced in volume and weight to some residual solids termed residue. The residue is composed of various dispersible solid materials and typically contains the resultant radioactivity from the waste. This report describes the immobilization of the residue in portland cement, borosilicate glass, and some other waste forms. Diagrams showing the cement and glass virtification parameters are included in the report as well as process steps and candidate waste product forms. Cement immobilization is simplest and probably least expensive; glass vitrification exhibits the best overall volume reduction ratio

  11. Reaction of cyanide with Pt-nucleobase complexes: preparative, spectroscopic, and structural studies. Unexpected stability of Pt-thymine and Pt-uracil complexes

    Raudaschl-Sieber, G.; Lippert, B.

    1985-01-01

    In order to improve the understanding of the nature of the strongly bound cisplatin on DNA, the reactivity of a large number of complexes of cis-(NH 3 ) 2 Pt/sup II/ with the model nucleobases, 9-ethylguanine, 9-methyladenine, 1-methylcytisine, 1-methylthymine, and i-methyluracil, toward a large excess of cyanide was studied. The behavior of Pt-nucleobase complexes toward CN - is compared with that of simple Pt-amine complexes, and reactions of thiourea with two selected nucleobase complexes is reported. The relevance of these findings with respect to substitution reactions of Pt-nucleobase complexes and the nature of the tightly DNA-bound Pt, which cannot be removed by excess KCN, is discussed

  12. Radiolytic Preparation of Electrocatalysts with Pt-Co and Pt-Sn Nanoparticles for a Proton Exchange Membrane Fuel Cell

    Sang Kyum Kim

    2014-01-01

    Full Text Available Nanosized Pt-Sn/VC and Pt-Co/VC electrocatalysts were prepared by a one-step radiation-induced reduction (30 kGy process using distilled water as the solvent and Vulcan XC72 as the supporting material. While the Pt-Co/VC electrodes were compared with Pt/VC (40 wt%, HiSpec 4000, in terms of their electrocatalytic activity towards the oxidation of H2, the Pt-Co/VC electrodes were evaluated in terms of their activity towards the hydrogen oxidation reaction (HOR and compared with Pt/VC (40 wt%, HiSpec 4000, Pt-Co/VC, and Pt-Sn/VC in a single cell. Additionally, the prepared electrocatalyst samples (Pt-Co/VC and Pt-Sn/VC were characterized by transmission electron microscopy (TEM, scanning electron microscope (SEM, thermogravimetric analysis (TGA, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, electrochemical surface area (ECSA, and fuel cell polarization performance.

  13. MnO2/CNT supported Pt and PtRu nanocatalysts for direct methanol fuel cells.

    Zhou, Chunmei; Wang, Hongjuan; Peng, Feng; Liang, Jiahua; Yu, Hao; Yang, Jian

    2009-07-07

    Pt/MnO2/carbon nanotube (CNT) and PtRu/MnO2/CNT nanocomposites were synthesized by successively loading hydrous MnO2 and Pt (or PtRu alloy) nanoparticles on CNTs and were used as anodic catalysts for direct methanol fuel cells (DMFCs). The existence of MnO2 on the surface of CNTs effectively increases the proton conductivity of the catalyst, which then could remarkably improve the performance of the catalyst in methanol electro-oxidation. As a result, Pt/MnO2/CNTs show higher electrochemical active surface area and better methanol electro-oxidation activity, compared with Pt/CNTs. As PtRu alloy nanoparticles were deposited on the surface of MnO2/CNTs instead of Pt, the PtRu/MnO2/CNT catalyst shows not only excellent electro-oxidation activity to methanol with forward anodic peak current density of 901 A/gPt but also good CO oxidation ability with lower preadsorbed CO oxidation onset potential (0.33 V vs Ag/AgCl) and peak potential (0.49 V vs Ag/AgCl) at room temperature.

  14. Optical properties of monodispersive FePt nanoparticle films

    Lee, S.J.; Lo, C.C.H. [Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Yu, A.C.C. [Sony Corporation, Sendai Technology Center, 3-4-1 Sakuragi, Miyagi 985-0842 (Japan); Fan, M. [Center for Sustainable Environmental Technologies, Iowa State University, Ames, IA 50011 (United States)

    2004-10-01

    The optical properties of monodispersive FePt nanoparticle films were investigated using spectroscopic ellipsometry in the energy range of 1.5 to 5.5 eV. The monodispersive FePt nanoparticle film was stabilized on a Si substrate by means of an organosilane coupling film, resulting in the formation of a (Si/SiO{sub 2}/APTS/FePt nanoparticles monolayer) structure. Multilayer optical models were employed to study the contribution of the FePt nanoparticles to the measured optical properties of the monodispersive FePt nanoparticle film, and to estimate the optical properties of the FePt nanoparticle layer. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Reclaim/recycle of Pt/C catalysts for PEMFC

    Zhao, Jishi; He, Xiangming; Tian, Jianhua; Wan, Chunrong; Jiang, Changyin

    2007-01-01

    Platinum was reclaimed from Pt/C catalysts of the PEMFC by drying the degraded Pt/C catalysts at 80 o C for 3 h, followed by sintering at 600 o C for 6 h, dissolution by aqua fortis, purification with hydrochloric acid, reduction and filtration, successively. Pt/C catalysts were prepared again from the reclaimed Pt by two proposed processes, e.g., pH value control process and mass control process. The fuel cell with recycled catalysts presented a power density of over 0.18 W cm -2 . The reclaiming of Pt/C catalysts is a potential way for recycling Pt for PEMFC, reducing the cost of PEMFC

  16. Hydrodeoxygenation of Guaiacol Over Pt/Al-SBA-15 Catalysts.

    Yu, Mi Jin; Park, Sung Hoon; Jeon, Jong-Ki; Ryu, Changkook; Sohn, Jung Min; Kim, Sang Chai; Park, Young-Kwon

    2015-01-01

    Upgrading of bio-oil through catalytic hydrodeoxygenation (HDO) reaction was investigated for guaiacol as a model compound. A batch reactor was used for the reaction condition of 40 bar and 250 degrees C. The target product was cyclohexane. Pt/Al-SBA-15 with the Si/Al ratios of 20, 40, and 80 and Pt/HZSM-5 were used as the catalyst. The SBA-15 catalysts were characterized by N2 adsorption-desorption, X-ray diffraction analysis, and temperature programmed desorption of ammonia. The order of cyclohexane yield was Pt/Al-SBA-15 (Si/Al = 20) > Pt/Al-SBA-15(40) > Pt/Al-SBA-15 (80), indicating that the quantity of acid sites plays an important role in the HDO reaction. On the other hand, Pt/HZSM-5 led to a very low cyclohexane yield, in spite of its abundant strong acid sites, due to its small pore size.

  17. A pressure study of CePt{sub 3}B

    Rauch, Daniela; Suellow, Stefan [Institute of Condensed Matter Physics, University of Technology Braunschweig, Braunschweig (Germany); Hartwig, Steffen [Institute of Condensed Matter Physics, University of Technology Braunschweig, Braunschweig (Germany); BENSC, Helmholtz Zentrum Berlin, Berlin (Germany); Hidaka, Hiroyuki; Yamazaki, Seigo; Amitsuka, Hiroshi [Department of Physics, Hokkaido University, Sapporo (Japan); Bauer, Ernst [Institute of Solid State Physics, Vienna University of Technology, Vienna (Austria)

    2013-07-01

    CePt{sub 3}B is isostructural to the non-centro symmetric heavy-fermion superconductor CePt{sub 3}Si. In contrast to the latter system, CePt{sub 3}B exhibits a complex magnetically ordered state at low temperatures, with an antiferromagnetic phase below T{sub N}=7.8 K and a weakly ferromagnetic transition below T{sub C}∼5 K. CePt{sub 3}B can be understand as a low pressure variant of CePt{sub 3}Si. Here we report a study of CePt{sub 3}B by means of high pressure magnetization measurements, this way in particular accessing the pressure evolution of the ferromagnetic transition temperature T{sub C}. From our investigation up to about 40 kbar we observe an almost constant transition temperature T{sub C} with pressure. This behavior we discuss in the context of alloying studies on this material.

  18. Evaluation of residue-residue contact predictions in CASP9

    Monastyrskyy, Bohdan

    2011-01-01

    This work presents the results of the assessment of the intramolecular residue-residue contact predictions submitted to CASP9. The methodology for the assessment does not differ from that used in previous CASPs, with two basic evaluation measures being the precision in recognizing contacts and the difference between the distribution of distances in the subset of predicted contact pairs versus all pairs of residues in the structure. The emphasis is placed on the prediction of long-range contacts (i.e., contacts between residues separated by at least 24 residues along sequence) in target proteins that cannot be easily modeled by homology. Although there is considerable activity in the field, the current analysis reports no discernable progress since CASP8.

  19. Penerapan Budaya Organisasi pada Pt.pln(persero) Rayon Bangkinang

    ", Kasmiruddin; Supariyanto, Sugeng

    2014-01-01

    This research was conducted at PT. PLN (Persero) rayon Bangkinang with the title on the application oforganizational culture PT.PLN (Persero) Rayon Bangkinang. Knowing the purpose of this study is theapplication of organizational culture on PT. PLN (Persero) Rayon Bangkinang. And the benefits of thisresearch is to add insight and understanding of science in the field of Human Resource Management and toto increase knowledge and understanding of the culture of the organization but also for the ...

  20. Obtaining and characterizing the binary compound Zr3Pt

    Tanoni, Diego; Arico, Sergio F; Alonso, Paula R

    2006-01-01

    The equilibrium phases in the Zr - Pt binary system are not fully defined. Experiences carried out from 0% to 50% at. Pt in the equilibrium diagram of Zr-Pt phases in 2001 revealed the presence of the intermetallic compounds Zr 2 Pt, Zr 5 Pt 3 , ZrPt (already previously identified by other authors) and a compound of 25% composition at Pt with an unidentified crystalline structure. This experimental work aims to fill out the information on this compound by characterizing its crystallography. An alloy was produced in the binary system Zr-Pt with a composition close to the stoichiometry by casting in an arc furnace, and was studied by optic and electronic metallography. The identification and crystallographic characterization of the phase is based on measurements of composition in electronic microwave and on analysis of spectrums obtained by X-ray diffraction. The results are presented, showing the presence in the cast structure of the solid solution zircon phases (hexagonal) and of the inter-metallic compound Zr 5 Pt 3 . These two phases were identified in the X-ray diffraction diagrams as well as the presence of other reflections that are associated with the inter-metallic Zr 3 Pt. The measurements of composition consistently reveal the presence of a phase of 25%at Pt composition. The structure's morphology shown in metallographies reveals the occurrence of a eutectic type transformation during cooling. We conclude that the formation of the phase sought in a composition 25 % at Pt should occur at temperatures below the eutectic transformation, and could be a peritectoid formation as was previously proposed. Therefore, the sample needs to be homogenized with thermal treatments that favor the formation and stabilization of the compound (CW)

  1. Penetapan Strategi Bisnis pada PT. Pabrik Es Siantar, Pematangsiantar

    Pakpahan, Vovi Novita

    2015-01-01

    This research aims to identify the types of strategies used dan analyze the internal environment PT. Pabrik Es Siantar related strenghts and weaknesses and the external environment related opportunities and threats to determine the right strategy and the way it is applied in PT. Pabrik Es Siantar in the face of competition. The type of strategy adopted PT. Pabrik Es Siantar classified as a defensive strategy. The input stage of business strategy include matrix EFE,IFE and CPM. The total ...

  2. Penerapan Strategi Bauran Pemasaran Pada PT. Asuransi Jiwasraya Medan

    Derby

    2016-01-01

    In marketing it's products PT. Asuransi Jiwasraya Medan require particular marketing strategy marketing mix strategy that Product strategy, price, promotion, place, people, processes, physical evidence. problems faced is the income PT. Asuransi Jiwasraya Medan has increased every year PT. Asuransi Jiwasraya Medan field should maximize it's strategy of increasing the number of sales in order to compete with other insurance companies therefore need a good marketing strategy to increase sales in...

  3. Perencanaan Enterprise Architecture Pada Perusahaan Manufaktur PT. Z

    Hartedja, Odwin Viator; Santoso, Leo Willyanto; Rostianingsih, Silvia

    2015-01-01

    PT.Z is a well-known producer and manufacturer of paint in Indonesia with years of experience in paint industry which produce many varieties of paint such as Decorative Coating (water and solvent based), automotive coating, Industrial Coating and Heavy Duty Coating. PT.Z has several subsidiaries all over Indonesia to elevate its product distribution. In the business process, PT.Z applies Information System to support and enhance the overall business. But, the current Information System applie...

  4. Pt-Pd nanoelectrocatalyst of ultralow Pt content for the oxidation of ...

    formic acid oxidation on Pt4Pd96 nanoparticles. Keywords. ..... Choi J H, Jeong K J, Dong Y, Han J, Lim T H, Lee J S ... Rhee C K, Kim B J, Ham C, Kim Y J, Song K and Kwon ... Wang R, Liao S and Ji S 2008 J. Power Sources 180 205. 18.

  5. Low Pt content Pt-Ru-Ir-Sn quaternary catalysts for anodic methanol oxidation in DMFC

    Neburchilov, Vladimir; Wang, Haijiang; Zhang, Jiujun [Institute for Fuel Cell Innovation, National Research Council (Canada)

    2007-07-15

    In this communication we report our research work on low Pt content Pt-Ru-Ir-Sn quaternary catalysts for use in DMFC anodes. The carbon-supported quaternary metal alloy catalyst was synthesized according to the solution reduction method and was deposited onto a carbon fiber paper or a carbon aerogel nanofoam to form the anode for direct methanol fuel cells. The Pt loading of the electrode is 0.1 mg/cm{sup 2}. The testing results from a three-electrode electrochemical cell show that the simultaneous use of higher Ir (25-35 wt.%) and Sn (10 wt.%) content gives satisfactory stability and higher activity for methanol oxidation than the commercially available E-TEK anode (80%[0.5Pt 0.5Ru]/C on carbon cloth). Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscope (SEM), and Bruner-Emmett-Teller method (BET) measurements were carried out to characterize the composition, structure, morphology, and surface area of the developed catalysts. (author)

  6. PtxGd alloy formation on Pt(111): Preparation and structural characterization

    Ulrikkeholm, Elisabeth Therese; Pedersen, Anders Filsøe; Vej-Hansen, Ulrik Grønbjerg

    2016-01-01

    (ring operator)C. The LEED and synchrotron XRD experiments have shown that a slightly compressed (2 ×2) alloy appear. The alloy film followed the orientation of the Pt(111) substrate half the time, otherwise it was rotated by 30(ring operator). The TPD spectra show a well-defined peak shifted down 200...

  7. Conducting filaments in Pt/ZrCuO{sub y}/Pt resistive switching memory cells

    Tulu, Berhanu [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Chu, Jinn P., E-mail: jpchu@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Wang, Sea-Fue [Department of Materials and Minerals Resources Engineering, National Taipei University of Technology, Taipei 10608, Taiwan (China)

    2015-11-15

    Forming-free unipolar resistive switching with good retention time, low voltage (<1.9 V) and thin thickness (∼11 nm) is obtained in oxygen deficient Pt/ZrCuO{sub y}/Pt devices. Annealing at 150 °C is beneficial to improve the endurance from 286 to >6 × 10{sup 3} and the resistance ratio from ∼13 to ∼25. Nanoscale current path images observed using a conductive atomic force microscope reveal a current density of ∼3.0 × 10{sup 2} nA/μm{sup 2} in the ON state, almost four orders of magnitude higher than ∼3.3 × 10{sup −2} nA/μm{sup 2} in the OFF state. The resistive switching is thought to be dominated by the oxygen vacancies, which serves as the filamentary conduction in the film. - Highlights: • Oxygen deficient Pt/ZrCuOy/Pt device after annealing at 150 °C is studied. • Forming-free resistive switching with good retention time, low voltage is obtained. • Annealing is shown to improve the endurance from 286 to >6 × 10{sup 3}. • The resistive switching is thought to be dominated by the oxygen vacancies.

  8. Temperature effect on the electrode kinetics of ethanol oxidation on Pd modified Pt electrodes and the estimation of intermediates formed in alkali medium

    Mahapatra, S.S.; Dutta, A.; Datta, J.

    2010-01-01

    Ethanol has been recognized as the ideal fuel for direct alcohol fuel cell (DAFC) systems due to its high energy density, non-toxicity and its bio-generation. However the complete conversion of ethanol to CO 2 is still met with challenges, due to dearth of suitable catalysts for the electro-oxidation. In the present work the effect of temperature on the catalytic oxidation of ethanol in alkaline medium over electrodeposited Pt and Pt-Pd alloyed nano particles on carbon support and also on the product formation during the course of reaction have been studied within the temperature range of 20-80 o C. The information on surface morphology, structural characteristics and bulk composition of the catalyst was obtained using SEM, XRD and EDX. BET surface area and pore widths of the catalyst particles were calculated by applying the BET equation to the adsorption isotherms. The electrochemical techniques like cyclic voltammetry, chronoamperometry and impedance spectroscopy were employed to investigate the electrochemical parameters related to electro-oxidation of ethanol in alkaline pH on the catalyst surfaces under the influence of temperature. The results show that the oxidation kinetics of ethanol on the alloyed Pt-Pd/C catalysts is significantly improved compared to that on Pt alone. The observations were interpreted in terms of the synergistic effect of higher electrochemical surface area, preferred OH - adsorption on the surface and the ad-atom contribution of the alloyed matrix. A pronounced influence of temperature on the reaction kinetics was manifested in the diminution of charge transfer resistance and activation energy of the ethanol oxidation with Pd incorporation into the Pt matrix, ensuring greater tolerance of the alloyed catalyst towards ethanolic residues. The higher yield of the reaction products like acetate and CO 3 -2 on the alloyed catalyst compared to Pt alone in alkaline medium, as estimated by ion chromatography, further substantiates the

  9. Crystal structure and physical properties of new Ca{sub 2}TGe{sub 3} (T = Pd and Pt) germanides

    Klimczuk, T., E-mail: tomasz.klimczuk@pg.gda.pl [Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80–233 Gdansk (Poland); Xie, Weiwei [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Winiarski, M.J.; Kozioł, R.; Litzbarski, L.S. [Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80–233 Gdansk (Poland); Luo, Huixia; Cava, R.J. [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States)

    2016-11-15

    The crystallographic, electronic transport and thermal properties of Ca{sub 2}PdGe{sub 3} and Ca{sub 2}PtGe{sub 3} are reported. The compounds crystalize in an ordered variant of the AlB{sub 2} crystal structure, in space group P6/mmm, with the lattice parameters a = 8.4876(4) Å/8.4503(5) Å and c = 4.1911(3) Å/4.2302(3) Å for Ca{sub 2}PdGe{sub 3} and Ca{sub 2}PtGe{sub 3}, respectively. The resistivity data exhibit metallic behavior with residual-resistivity-ratios (RRR) of 13 for Ca{sub 2}PdGe{sub 3} and 6.5 for Ca{sub 2}PtGe{sub 3}. No superconducting transition is observed down to 0.4 K. Specific heat studies reveal similar values of the Debye temperatures and Sommerfeld coefficients: Θ{sub D} = 298 K, γ = 4.1 mJ mol{sup −1} K{sup −2} and Θ{sub D} = 305 K, γ = 3.2 mJ mol{sup −1} K{sup −2} for Ca{sub 2}PdGe{sub 3} and Ca{sub 2}PtGe{sub 3}, respectively. The low value of γ is in agreement with the electronic structure calculations.

  10. Synthesis and characterization of diverse Pt nanostructures in Nafion.

    Ingle, N J C; Sode, A; Martens, I; Gyenge, E; Wilkinson, D P; Bizzotto, D

    2014-02-25

    With the aid of TEM characterization, we describe two distinct Pt nanostructures generated via the electroless reduction of Pt(NH3)4(NO2)2 within Nafion. Under one set of conditions, we produce bundles of Pt nanorods that are 2 nm in diameter and 10-20 nm long. These bundled Pt nanorods, uniformly distributed within 5 μm of the Nafion surface, are strikingly similar to the proposed hydrated nanomorphology of Nafion, and therefore strongly suggestive of Nafion templating. By altering the reaction environment (pH, reductant strength, and Nafion hydration), we can also generate nonregular polyhedron Pt nanoparticles that range in size from a few nanometers in diameter up to 20 nm. These Pt nanoparticles form a dense Pt layer within 100-200 nm from the Nafion surface and show a power-law dependence of particle size and distribution on the distance from the Nafion membrane surface. Control over the distribution and the type of Pt nanostructures in the surface region may provide a cost-effective, simple, and scaleable pathway for enhancing manufacturability, activity, stability, and utilization efficiency of Pt catalysts for electrochemical devices.

  11. Reactivity of hydrogen with uranium in the presence of Pt

    Balooch, M.; Siekhaus, W.J.

    1997-07-01

    The surface-reaction of di-hydrogen with uranium in the presence of Pt clusters has been studied using scanning tunneling microscopy (STM). Uranium was deposited on highly oriented pyrolytic graphite (HOPG) and annealed at temperatures up to 1200 degrees C to obtain atomically pyrolytic flat surfaces. Pt clusters were then formed using evaporation from a Pt source onto the surface and subsequent annealing. Hydrogen mainly attacked uranium in the vicinity of Pt clusters and formed hydride. The hydride formation probability is almost constant at 2.3x10 -4 over the range of exposures studied

  12. Intrinsic states and rotational bands in 177Pt

    Dracoulis, G.D.; Fabricius, B.; Bark, R.A.; Stuchbery, A.E.; Popescu, D.G.; Kibedi, T.

    1989-11-01

    The 149 Sm ( 32 S,4n) 177 Pt reaction has been used to populate excited states in the neutron-deficient nucleus 177 Pt. Rotational bands based on intrinsic states assigned to the 1/2-[521], 5/2-[521] and (mixed) 7/2+ [633] Nilsson configurations have been observed. In contrast to the neighbou-ring even isotope 176 Pt, anomalies attributed to shape co-existence at low spin have not been observed. Implications for the deformation of 177 Pt are discussed together with the systematics of intrinsic states in this region, and alignments and other properties of N=99 nuclei. 37 refs., 15 figs., 3 tabs

  13. Electrochemical properties of mixed WC and Pt-black powders

    MAJA D. OBRADOVIC

    2008-12-01

    Full Text Available The electrochemical characteristics of a mixture of Pt-black and WC powders and its catalytic activity for methanol and formic acid oxidation were investigated in acid solution. XRD and AFM measurements revealed that the WC powder employed for the investigation was a single-phase material consisting of crystallites/spherical particles of average size of about 50 nm, which were agglomerated into much larger particles. Cyclic voltammetry showed that the WC underwent electrochemical oxidation, producing tungstate species. In the case of the mixed Pt + WC powders, the tungstate species were deposited on the Pt as a thin film of hydrous tungsten oxide. Enhanced hydrogen intercalation in the hydrous tungsten oxide was observed and it was proposed to be promoted in mixed powders by the presence of hydrogen adatoms on bare Pt sites. The determination of Pt surface area in the Pt + WC layer by stripping of underpotentially deposited Cu revealed that the entire Pt surface was accessible for underpotential deposition of Cu. Investigation of the electrochemical oxidation of methanol and formic acid on Pt + WC and pure Pt layers did not indicate electrocatalytic promotion due to the presence of WC.

  14. Au(111) and Pt(111) surface phase behavior

    Sandy, A.R.; Mochrie, S.G.J.; Zehner, D.M.

    1993-01-01

    We describe our recent X-ray scattering studies of the structure and phases of the clean Au(111) and Pt(111) surfaces. Below 0.65 of their respective bulk melting temperatures, the Au(111) surface has a well-ordered chevron reconstruction and the Pt(111) surface is unreconstructed. Above these te......We describe our recent X-ray scattering studies of the structure and phases of the clean Au(111) and Pt(111) surfaces. Below 0.65 of their respective bulk melting temperatures, the Au(111) surface has a well-ordered chevron reconstruction and the Pt(111) surface is unreconstructed. Above...

  15. Characterization of Pt catalysts supported in mixed oxides

    Perez H, R.; Garcia C, M.A.; Gomez C, A.; Diaz, G.

    1999-01-01

    The catalytic supports TiO 2 , ZrO 2 and TiO 2 -ZrO 2 were prepared by the sol-gel technique. The incorporation of Pt to the supports was by the classical impregnation method. The catalytic materials were characterized (Pt/TiO 2 , Pt/ZrO 2 and Pt/TiO 2 -ZrO 2 ) by diverse techniques to determine: the texture (BET), evolution of the catalytic materials synthesised after drying and calcination (Infrared spectroscopy) and by Thermogravimetric analysis. (Author)

  16. Landfilling of waste incineration residues

    Christensen, Thomas Højlund; Astrup, Thomas; Cai, Zuansi

    2002-01-01

    Residues from waste incineration are bottom ashes and air-pollution-control (APC) residues including fly ashes. The leaching of heavy metals and salts from the ashes is substantial and a wide spectrum of leaching tests and corresponding criteria have been introduced to regulate the landfilling...

  17. Effect of Pt:Sn atomic ratio on the preparation of PtSn/C electrocatalysts using electron beam irradiation

    Silva, Dionisio F.; Oliveira Neto, Almir; Pino, Eddy S.; Linardi, Marcelo; Spinace, Estevam V.

    2009-01-01

    PtSn/C electrocatalysts were prepared with Pt:Sn atomic ratios of 3:1, 1:1 and 1:3 in water/2-propanol using electron beam irradiation. The obtained materials were characterized by EDX, XRD and cyclic voltammetry. The ethanol electro-oxidation was studied by chronoamperometry. The XRD diffractograms of the PtSn/C electrocatalysts showed typical face-centered cubic (fcc) structure of platinum and the presence of a SnO 2 phase (cassiterite). The mean crystallite sizes of Pt fcc phase was in the range of 3.0-3.5 nm. The PtSn/C electrocatalysts were active for ethanol electro-oxidation at room temperature and the material prepared with Pt:Sn atomic ratio of 1:1 showed the best activity. (author)

  18. Effect of Pt:Sn atomic ratio on the preparation of PtSn/C electrocatalysts using electron beam irradiation

    Silva, Dionisio F.; Oliveira Neto, Almir; Pino, Eddy S.; Linardi, Marcelo; Spinace, Estevam V., E-mail: dfsilva@ipen.b, E-mail: espinace@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    PtSn/C electrocatalysts were prepared with Pt:Sn atomic ratios of 3:1, 1:1 and 1:3 in water/2-propanol using electron beam irradiation. The obtained materials were characterized by EDX, XRD and cyclic voltammetry. The ethanol electro-oxidation was studied by chronoamperometry. The XRD diffractograms of the PtSn/C electrocatalysts showed typical face-centered cubic (fcc) structure of platinum and the presence of a SnO{sub 2} phase (cassiterite). The mean crystallite sizes of Pt fcc phase was in the range of 3.0-3.5 nm. The PtSn/C electrocatalysts were active for ethanol electro-oxidation at room temperature and the material prepared with Pt:Sn atomic ratio of 1:1 showed the best activity. (author)

  19. Strategi Bisnis pada PT Wirapati Garuda Paksi

    Rina Astini

    2010-03-01

    Full Text Available PT Garuda Wirapati Paksi (WGP is a private corporation engaged in the Security and Rescue Services Business Sector (BUJPP in guarding. Many challenges arise from the external environment such as unstable political and economic conditions, competition among companies and the entry of foreign firms. To face the above phenomenon, the right and effective business strategy is the right tool for avoiding the challenge. Business strategy planning is absolutely necessary for companies that want to survive in the future. The research method is descriptive. Data collection techniques used are questionnaire and interview with relevant parties within the company. The data have been obtained that, in the analysis through three phases, namely input, matching, and decision stage. The final results of this study concluded that the proposed effective business strategy for PT Garuda Wirapati Paksi based on QSPM matrix is Market Penetration Strategy. This strategy is considered to reduce business risk arising as a result of significant changes to the external environment of the company.

  20. Efektifitas Pelaksanan Program CSR PT Tirta Bahagia

    Anggara Prihardana

    2015-12-01

    Full Text Available CSR first appeared in official discourse since the presence of academic writings of Howard Bowen, entitled Social Responsibility of Businessmen raised in 1953. CSR in the meaning of Bowen refers to the obligation of business to make and implement policies, decisions, and actions that follow the norms in a society. In the implementation of the program of corporate social responsibility (CSR, PT Tirta Bahagia has a lot of activities in the field of education, the environment or health. In carrying out these activities there are several stages performed i.e. ranging from planning, implementation, and evaluation. In this discussion that became the focus of research is on the development of the well absorption done by the company in the village which is also the location of the factory. PT Tirta Bahagia starting the planning stages are not based on the order in which they should be, i.e. starts with vision and mission would formulate but positioning the provision of funds (budget being the first with reason a very limited source of funding, causing the program to be run CSR activities should be adapted to the existing funds.

  1. Gender politics in the PT government

    Fiona MACAULAY

    2011-01-01

    Full Text Available What difference will a Workers’ Party (Partido dos Trabalhadores-PT govern­ment make to women’s status and rights in Brazil? In order to analyse the Lula government’s approach to gender issues, the article first examines the party’s foundation and development, and relationship to social movements, including the women’s movement. The PT is shown to be a groundbreaker in the Brazilian party system, in terms both of promoting women’s leadership and of its ideological and institutional commitment to gender equity and equality, as illustrated by the party’s state and municipal governments, by its actions in the legislative sphere. The article then analyses the likely direction of the new Special Secretariat for Policies on Women in the light of the previous, uneven trajectory of Brazil’s national machinery for promoting women’s status, and of the kinds of gender policy orientations discernible in the party’s subnational administrations. It concludes by analysing some of the gender policies put forward since the beginning of the Lula government in January 2003.

  2. Statistical inference on residual life

    Jeong, Jong-Hyeon

    2014-01-01

    This is a monograph on the concept of residual life, which is an alternative summary measure of time-to-event data, or survival data. The mean residual life has been used for many years under the name of life expectancy, so it is a natural concept for summarizing survival or reliability data. It is also more interpretable than the popular hazard function, especially for communications between patients and physicians regarding the efficacy of a new drug in the medical field. This book reviews existing statistical methods to infer the residual life distribution. The review and comparison includes existing inference methods for mean and median, or quantile, residual life analysis through medical data examples. The concept of the residual life is also extended to competing risks analysis. The targeted audience includes biostatisticians, graduate students, and PhD (bio)statisticians. Knowledge in survival analysis at an introductory graduate level is advisable prior to reading this book.

  3. Magnetic Properties and Microstructure of FeOx/Fe/FePt and FeOx/FePt Films

    Jai-Lin Tsai

    2013-01-01

    Full Text Available The Fe(6 nm/FePt film with perpendicular magnetization was deposited on the glass substrate. To study the oxygen diffusion effect on the coupling of Fe/FePt bilayer, the plasma oxidation with 0.5~7% oxygen flow ratio was performed during sputtered part of Fe layer and formed the FeOx(3 nm/Fe(3 nm/FePt trilayer. Two-step magnetic hysteresis loops were found in trilayer with oxygen flow ratio above 1%. The magnetization in FeOx and Fe/FePt layers was decoupled. The moments in FeOx layer were first reversed and followed by coupled Fe/FePt bilayer. The trilayer was annealed again at 500°C and 800°C for 3 minutes. When the FeOx(3 nm/Fe(3 nm/FePt trilayer was annealed at 500°C, the layers structure was changed to FeOx(6 nm/FePt bilayer due to oxygen diffusion. The hard-magnetic FeOx(6 nm/FePt film was coupled with single switching field. The FeOx/(disordered FePt layer structure was observed with further annealing at 800°C and presented soft-magnetic loop. In summary, the coupling between soft-magnetic Fe, FeOx layer, and hard-magnetic L10 FePt layer can be controlled by the oxygen diffusion behavior, and the oxidation of Fe layer was tuned by the annealing temperature. The ordered L10 FePt layer was deteriorated by oxygen and became disordered FePt when the annealed temperature was up to 800°C.

  4. Effect of irradiation on foodstuffs Pt. 4. A literature study. Der Einfluss der Strahlenbehandlung auf Lebensmittel. T. 4. Eine Literaturstudie

    Kluender, U; Boegl, W

    1980-01-01

    In the present study of the relevant literature the results of irradiation experiments with 32 foodstuffs have been compiled and discussed. This study is intented to give a survey on chemical changes in irradiated food, and neither microbiological nor toxicological and physiological aspects were taken into account. The results published by the authors of the original papers have been compiled in form of a dictionary which contains all important data such as radiation source, irradiation conditions, treatment and characteristics of the sample, investigation methods, results of the chemical and organoleptical changes etc. In addition, the effects of irradiation both on individual food substances and individual groups of foodstuffs have been summarized. Furthermore, the effects of irradiation on sensory characteristics and the atmospheric influence during irradiation are given seperately. The last chapter contains a comparison between the chemical changes of food due to irradiation treatment and those caused by conventional methods. The final discussion of the results will be published seperately.

  5. Shape-dependent surface magnetism of Co-Pt and Fe-Pt nanoparticles from first principles

    Liu, Zhenyu; Wang, Guofeng

    2017-12-01

    In this paper, we have performed the first-principles density functional theory calculations to predict the magnetic properties of the CoPt and FePt nanoparticles in cuboctahedral, decahedral, and icosahedral shapes. The modeled alloy nanoparticles have a diameter of 1.1 nm and consist of 31 5 d Pt atoms and 24 3 d Co (or Fe) atoms. For both CoPt and FePt, we found that the decahedral nanoparticles had appreciably lower surface magnetic moments than the cuboctahedral and icosahedral nanoparticles. Our analysis indicated that this reduction in the surface magnetism was related to a large contraction of atomic spacing and high local Co (or Fe) concentration in the surface of the decahedral nanoparticles. More interestingly, we predicted that the CoPt and FePt cuboctahedral nanoparticles exhibited dramatically different surface spin structures when noncollinear magnetism was taken into account. Our calculation results revealed that surface anisotropy energy decided the fashion of surface spin canting in the CoPt and FePt nanoparticles, confirming previous predictions from atomistic Monte Carlo simulations.

  6. The thermodynamic assessment of the As-Pt system and the analysis of the Pt/GaAs interfacial reactions

    Li, Mei; Li, Changrong; Wang, Fuming; Zhang, Weijing

    2007-01-01

    In order to analyze the Pt/GaAs interfacial reaction sequence, the As-Pt binary system was thermodynamically assessed. A consistent thermodynamic data set for the As-Pt binary system have been obtained by means of calculation of phase diagrams (CALPHAD) technology. The intermetallic compound, As 2 Pt, was treated as stoichiometric compound. The gas phase was treated as an ideal mixture. Using the present thermodynamic data set for the As-Pt system and the literatures reported ones for the Ga-Pt and As-Ga systems, the isothermal sections of the As-Ga-Pt system at different temperatures 873 and 298 K were constructed by extending the related binaries. The calculated phase diagrams reproduce the experimental results well. Based on the present optimized data and the phase equilibrium calculation, the interfacial reactions of (bulk Pt)/GaAs and (thin-film Pt)/GaAs couples were analyzed and the phase formation sequences were predicted. The calculation results agree well with the reported experiments

  7. Tritium-tracer study of catalytic hydrogenation reaction of ethylene on Ni, Pt and Ni-Pt

    Matsuyama, M.; Yasuda, Y.; Takeuchi, T.

    1978-01-01

    The influence of the pressure of tritiated hydrogen on the rate of the formation of tritiated ethylene, X, and that of tritiated ethane, Z, in the hydrogenation reaction of ethylene on Ni, Pt and Ni-Pt (1:1) alloy catalysts was investigated. The ratio of the rate of the exchange to that of the hydrogenation, selectivity X/Z, decreased markedly with the increase in the pressure of the tritiated hydrogen and the order of X/Z was Ni>Ni-Pt>Pt. These results were interpreted in terms of the difference in the amount of chemisorbed tritium on each metal catalyst. (orig.) [de

  8. Segregation and stability at Pt3Ni(1 1 1) surfaces and Pt75Ni25 nanoparticles

    Fowler, Ben; Lucas, Christopher A.; Omer, Ahmed; Wang, Guofeng; Stamenkovic, Vojislav R.; Markovic, Nenad M.

    2008-01-01

    Using in situ surface X-ray diffraction we have determined the atomic structure and stability of a Pt 3 Ni(1 1 1) surface in the electrochemical environment. Surface segregation leads to a pure Pt(1 1 1) skin with enrichment of Ni in the sub-surface atomic layer that determines the surface electronic structure. The Pt-skin surface exhibits inward relaxation upon the adsorption of oxygenated species and this explains the surface stability compared to pure Pt(1 1 1). Using Monte Carlo calculations it is shown that nanoparticles with the same surface composition and stochiometry are energetically stable

  9. Characterization of Pt catalysts supported in mixed oxides; Caracterizacion de catalizadores de Pt soportado en oxidos mixtos

    Perez H, R.; Garcia C, M.A.; Gomez C, A.; Diaz, G. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The catalytic supports TiO{sub 2}, ZrO{sub 2} and TiO{sub 2}-ZrO{sub 2} were prepared by the sol-gel technique. The incorporation of Pt to the supports was by the classical impregnation method. The catalytic materials were characterized (Pt/TiO{sub 2}, Pt/ZrO{sub 2} and Pt/TiO{sub 2}-ZrO{sub 2}) by diverse techniques to determine: the texture (BET), evolution of the catalytic materials synthesised after drying and calcination (Infrared spectroscopy) and by Thermogravimetric analysis. (Author)

  10. High Pt utilization PEMFC electrode obtained by alternative ion-exchange/electrodeposition.

    Chen, Siguo; Wei, Zidong; Li, Hua; Li, Li

    2010-12-14

    High Pt utilization PEMFC electrodes were prepared by an alternative ion-exchange/electrodeposition (AIEE) technique. The results demonstrated that the MEA employing an AIEE electrode with a Pt loading of 0.014 mg Pt cm(-2) exhibits performance approximately 2.2 times larger than that employing a conventional Nafion-bonded Pt/C electrode with a same Pt loading.

  11. Determining permissible PT parameters in normal operating conditions for reactor pressure vessel of units 1-4 of NPP Kozloduy

    Batischev, M.; Yurukov, V.; Simovski, Ts.

    2000-01-01

    The main objective of the analysis is to verify the determined from the Main Designer P-T curves and to provide that permissible T values can be decreased even in case a lot of very conservative assumptions are taken into account. Detailed temperature and stress distributions are obtained using different 3D Finite Element Models. Then, assuming linear elastic behaviour and using these distributions onto models including cracks K I values are determined. From the K I values taking into account material characteristics and actual and prognostic neutron fluence of the most sensitive areas of the RPV, P-T curves are determined. Residual stresses in welds are also taken into account. Analysis has been performed independently following two different methodologies - one prescribed by Russian norms (PNAEh-G-7-002-86) and another, developed by the IAEA - 'Guidelines on PTS analysis for WWER NPP'. The obtained results using two methodologies are compared and the more severe are determined

  12. Spin-orbit driven phenomena in the isoelectronic L 10 -Fe(Pd,Pt) alloys from first principles

    Kudrnovský, J.; Drchal, V.; Turek, I.

    2017-12-01

    The anomalous Hall effect (AHE) and the Gilbert damping (GD) are studied theoretically for the partially ordered L 10 -Fe(Pd,Pt) alloys. The varying alloy order and the spin-orbit coupling, which are due to the change in the Pd/Pt composition, allow for a chemical tuning of both phenomena which play an important role in the spintronic applications. The impact of the antisite disorder on the residual resistivity, AHE, and GD is studied from first principles using recently developed methods employing the Kubo-Bastin approach and the nonlocal torque operator method. The most interesting result is a different behavior of samples with low and high chemical orders. Good agreement between calculated and measured concentration trends is obtained for all quantities studied, while the absolute GD values are underestimated.

  13. Hydrogen from bioethanol on Pt/Hydrotalcite catalysts stabilized with WOx; Hidrogeno a partir de bioetanol sobre catalizadores de Pt/hidrotalcita estabilizados con WOx

    Ortiz, M.A.; Contreras, J.L. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D.F. (Mexico)]. E-mail: jlcl@correo.azc.uam.mx; Fuentes, G.A. [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D.F. (Mexico); Luna, R. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico, D.F. (Mexico); Salmones, J.; Zeifert, B. [ESIQIE, Instituto Politecnico Nacional, Mexico, D.F. (Mexico)] Vazquez, A. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2009-09-15

    To produce H{sub 2} from bio-ethanol, the synthesis, characterization and reaction of Pt catalysts exchanged with hydrotalcite were studied. The catalysts obtained were characterized with BET area, x-ray diffraction and Raman, Infrared and UV-vis spectroscopies. The catalytic evaluation was performed with micro-reaction equipment using a water/ethanol ratio of 4 at 45 degrees Celsius. The effect of the W contents was from 0.5 to 3%. X-ray diffraction of the Co and Ni series showed a continuous decrease in crystallinity as W contents increased. Findings from N{sub 2} adsorption show pores in the form of parallel plates and a mesoporous distribution (bimodal) with areas between 151-257 m{sup 2}/g. OH, H{sub 2}O, Al-OH, Mg-OH, W-O and CO32- vibrations and W-O-W surface bonds were observed using infrared and Raman spectroscopy. Tungsten oxide groups were found with UV-vis spectroscopy. The catalyst with the greatest selectivity and stability is between 0.5 and 1% of W, and the highest stability is after 7 h of reaction. In this Pt series, the reaction that most consumed ethanol was that which produces CH{sub 4} and CO{sub 2}. The total conversion increased in function of W contents, between 0.5 and 3%. W stabilized the Pt/hydrotalcite catalyst with 0.5%W being the optimal concentration. The least amount of C{sub 2}H{sub 4} production and no CO was found for this Pt catalyst. [Spanish] Para la produccion de H{sub 2} se estudio la sintesis, caracterizacion y reaccion de catalizadores de Pt intercambiados con hidrotalcita, a partir de bioetanol. Los catalizadores obtenidos se caracterizaron por: area BET, difraccion de rayos X, espectroscopias: Raman, Infrarrojo y UV-vis. La evaluacion catalitica se llevo a cabo en un reactor de lecho fijo usando una relacion agua/etanol de 4 a 450 grados centigrados, se estudio el efecto del contenido de W desde 0.5 hasta 3% en peso. Conforme aumento el contenido de W se encontro por difraccion de rayos X un aumento de la cristalinidad

  14. Residual stress by repair welds

    Mochizuki, Masahito; Toyoda, Masao

    2003-01-01

    Residual stress by repair welds is computed using the thermal elastic-plastic analysis with phase-transformation effect. Coupling phenomena of temperature, microstructure, and stress-strain fields are simulated in the finite-element analysis. Weld bond of a plate butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. Microstructure is considered by using CCT diagram and the transformation behavior in the repair weld is also simulated. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress. (author)

  15. Chemonuclear studies for identification for new production routes for the therapeutically useful radionuclides {sup 140}Nd, {sup 192}Ir, {sup 191}Pt, {sup 193m}Pt, und {sup 195m}Pt; Kernchemische Studien zur Entwicklung neuerer Produktionsverfahren fuer die therapierelevanten Radionuklide {sup 140}Nd, {sup 192}Ir, {sup 191}Pt, {sup 193m}Pt, und {sup 195m}Pt

    Hilgers, K.

    2005-12-15

    New production routes for the therapeutically useful radionuclides {sup 140}Nd, {sup 192}Ir, {sup 191}Pt, {sup 193m}Pt and {sup 195m}Pt were investigated. Cross section data were measured using the stacked-foil technique and compared with theoretical calculations. A production method for the platinum nuclides was developed. The {sup 141}Pr(p, 2n){sup 140}Nd and {sup nat}Ce({sup 3}He, xn){sup 140}Nd reactions were investigated for production of {sup 140}Nd. Cross section data of nuclear reactions leading to the side products {sup 141}Nd, {sup 139}Nd and {sup 139}Ce could also be achieved. The experimental data were compared with theoretical calculations using the code ALICE-IPPE. A comparison of the calculated thick target yields showed that the {sup 141}Pr(p, 2n){sup 140}Nd reaction gives a higher yield. The {sup 192}Os(p, n){sup 192}Ir reaction was examined in the context of the production of {sup 192}Ir. Cross section data were determined and compared with theoretical calculations using the codes ALICE-IPPE and EMPIRE II. The yield of this reaction was compared with the yield of the reactor production of this nuclide. The reactor production seems to be more suitable because of a higher purity and yield. Cross section data were measured for the {sup 192}Os({alpha}, n){sup 195m}Pt, {sup 192}Os({alpha}, 3n){sup 193m}Pt and {sup 192}Os({sup 3}He, 4n){sup 191}Pt reactions. The activity of {sup 193m}Pt and {sup 195m}Pt was determined by X-ray spectroscopy after a chemical separation procedure. The ALICE-IPPE code was found to be inappropriate to reproduce the experimental values. The calculated yields were compared with the yields of other reactions, especially the reactor production of {sup 195m}Pt. The yield of the {sup 192}Os({alpha}, n){sup 195m}Pt reaction is lower compared to the yield of the reactor production, but offers lower target costs and higher specific activity. A production method for {sup 193m}Pt and {sup 195m}Pt was developed. Batch yields of 0.9 MBq

  16. Release of bound residues of atrazine from soils through autoclaving and gamma radiation sterilization

    Nakagawa, L.E.; Andréa, M.M.

    1997-01-01

    The sterilization methods are particularly important to study the influence of microorganisms on the pesticide dissipation in soils. This study, conducted in the laboratories of the Instituto Biológico of São Paulo in august 1996, tested the influence of two methods of soil sterilization - moist heat (autoclaving) and γ radiation - on the release of nonextractable or bound residues. It was studied, as example, bound residues of the herbicide atrazine in two types of soil (gley humic and dark red latosol). In the soil samples submitted to the moist heat sterilization, the recovery of the previously bound residues as reextractable residues was 5.6 and 5.9 times higher than in the control soils, not submitted to any sterilization process. Therefore, the method itself released the residues, indicating that the autoclaving is not the most appropriate method for studies on the influence of microorganisms on the release of bound residues. Otherwise, the γ radiation did not modify the residues recovery when compared to the controls. (author) [pt

  17. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  18. Evidence of complex magnetism in CePt3C

    Vejpravova, J.; Prokleska, J.; Danis, S.; Uhlirova, K.; Sechovsky, V.

    2006-01-01

    CePt 3 C has been synthesized and studied by powder X-ray diffraction (at RT), specific heat, resistivity and magnetization measurements at temperatures from RT down to 0.4K and in magnetic fields up to 10T. A possible scenario for the ground state of CePt 3 C based on the observed phenomena is proposed

  19. Microemulsion prepared Ni88Pt12 for methane cracking

    Zhou, Lu

    2017-01-16

    Monodispersed NiPt nanoparticles of 10 nm were synthesized by water-in-oil microemulsion. The Ni-Pt alloy structure was stable during the thermal treatment between 330 and 1037 °C, whereas the relatively low temperature range of 600-700 °C was favorable for methane cracking to produce hydrogen and carbon nanotubes.

  20. Ethanol tolerant Pt-alloy cathodes for DEFC applications

    Rodriguez Valera, F.J. [CINVESTAV Unidad Saltillo, Coahuila (Mexico). Grupo de Recursos Minerales y Energeticos; Savadogo, O. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour l' energie et l' electrochimie

    2008-07-01

    Direct ethanol fuel cells (DEFCs) based on Ru/C cathodes have interesting current density versus cell voltage behaviour. In particular, the selectivity towards the oxygen reduction reaction (ORR) in acid medium in the presence of ethanol was improved when this cathode material was used. This study quantified the degree of tolerance to ethanol and the electrocatalytic activity for the ORR. It compared the specific activity towards the ORR for Pt1Co1/C and Pt3Cr1/C. The study showed that these cathodes have a high tolerance to this alcohol and demonstrated the good performance of this type of Pt-alloy in a DEFC as oxygen reduction cathodes. The performance of the Pt1Co1/C alloy was shown to be better than the Pt3Cr1/C, even when the former had a lower Pt content. The enhanced catalytic behaviour of the PtCo/C alloy can be attributed to the higher degree of allying or a smaller mean particle size and a larger surface area. Polarization measurements with relatively high ethanol concentrations confirmed the good catalytic behaviour of the PtCo/C alloy as cathode in a DEFC operating at 90 degrees C. Current work is focusing on the variation of Co content in the alloy structure and the analysis of this change in terms of ORR activity, tolerance to ethanol and electrochemical behaviour in a DEFC. 10 refs., 5 figs.

  1. Chemically ordered face-centred tetragonal Fe–Pt nanoparticles ...

    2012-02-21

    Feb 21, 2012 ... Heat treatment of Fe/Pt co-doped films in air caused generation of Pt NPs first. At this stage, Fe .... water to salt can be varied from 26 to 28) and mixed with ..... electron diffraction (SAED) pattern (grey scale inverted; fig- ure 5c) ...

  2. Critical assessment of Pt surface energy - An atomistic study

    Kim, Jin-Soo; Seol, Donghyuk; Lee, Byeong-Joo

    2018-04-01

    Despite the fact that surface energy is a fundamental quantity in understanding surface structure of nanoparticle, the results of experimental measurements and theoretical calculations for the surface energy of pure Pt show a wide range of scattering. It is necessary to further ensure the surface energy of Pt to find the equilibrium shape and atomic configuration in Pt bimetallic nanoparticles accurately. In this article, we critically assess and optimize the Pt surface energy using a semi-empirical atomistic approach based on the second nearest-neighbor modified embedded-atom method interatomic potential. That is, the interatomic potential of pure Pt was adjusted in a way that the surface segregation tendency in a wide range of Pt binary alloys is reproduced in accordance with experimental information. The final optimized Pt surface energy (mJ/m2) is 2036 for (100) surface, 2106 for (110) surface, and 1502 for (111) surface. The potential can be utilized to find the equilibrium shape and atomic configuration of Pt bimetallic nanoparticles more accurately.

  3. Microemulsion prepared Ni88Pt12 for methane cracking

    Zhou, Lu; Harb, Moussab; Hedhili, Mohamed N.; Mana, Noor Al; Basset, Jean-Marie

    2017-01-01

    Monodispersed NiPt nanoparticles of 10 nm were synthesized by water-in-oil microemulsion. The Ni-Pt alloy structure was stable during the thermal treatment between 330 and 1037 °C, whereas the relatively low temperature range of 600-700 °C was favorable for methane cracking to produce hydrogen and carbon nanotubes.

  4. Mechanisms of self-diffusion on Pt(110)

    Lorensen, Henrik Qvist; Nørskov, Jens Kehlet; Jacobsen, Karsten Wedel

    1999-01-01

    The self-diffusion of Pt on the missing row reconstructed Pt(110) surface is discussed based on density functional calculations of activation energy barriers. Different competing diffusion mechanisms are considered and we show that several different diffusion paths along the reconstruction troughs...

  5. [Zn(NH3)4][PtCl6] and [Cd(NH3)4][PtCl6] as precursors for intermetallic compounds PtZn and PtCd

    Zadesenets, A.V.; Venediktov, A.B.; Shubin, Yu.V.; Korenev, S.V.

    2007-01-01

    Double complex salts (tetraamminezinc and tetraamminecadmium hexachloroplatinates) have been synthesized. Their thermal properties have been studied, as well as the products of their degradation in hydrogen and helium atmospheres. Optimal thermolysis schedules have been determined. Thermolysis under hydrogen yields intermetallic compounds PtZn and PtCd [ru

  6. A proposed phase equilibrium diagram for Pt-Zr system

    Arias, D.E.; Gribaudo, L.

    1993-01-01

    A revision of the phase diagram of the Pt-Zr system is presented using up to date information from recent publications. The proposed change concerning the invariant transformation in the Pt-rich zone is supported by simplified thermodynamic evaluations. (author). 12 refs., 1 fig

  7. Proton microbeam irradiation effects on PtBA polymer

    Microbeam irradiation effects on poly-tert-butyl-acrylate (PtBA) polymer using 2.0 MeV proton microbeam are reported. Preliminary results on pattern formation on PtBA are carried out as a function of fluence. After writing the pattern, a thin layer of Ge is deposited. Distribution of Ge in pristine and ion beam patterned surface ...

  8. Ethanol electrooxidation on novel carbon supported Pt/SnOx/C catalysts with varied Pt:Sn ratio

    Jiang, L.; Colmenares, L.; Jusys, Z.; Sun, G.Q.; Behm, R.J.

    2007-01-01

    Novel carbon supported Pt/SnO x /C catalysts with Pt:Sn atomic ratios of 5:5, 6:4, 7:3 and 8:2 were prepared by a modified polyol method and characterized with respect to their structural properties (X-ray diffraction (XRD) and transmission electron microscopy (TEM)), chemical composition (XPS), their electrochemical properties (base voltammetry, CO ad stripping) and their electrocatalytic activity and selectivity for ethanol oxidation (ethanol oxidation reaction (EOR)). The data show that the Pt/SnO x /C catalysts are composed of Pt and tin oxide nanoparticles with an average Pt particle diameter of about 2 nm. The steady-state activity of the Pt/SnO x /C catalysts towards the EOR decreases with tin content at room temperature, but increases at 80 deg. C. On all Pt/SnO x /C catalysts, acetic acid and acetaldehyde represent dominant products, CO 2 formation contributes 1-3% for both potentiostatic and potentiodynamic reaction conditions. With increasing potential, the acetaldehyde yield decreases and the acetic acid yield increases. The apparent activation energies of the EOR increase with tin content (19-29 kJ mol -1 ), but are lower than on Pt/C (32 kJ mol -1 ). The somewhat better performance of the Pt/SnO x /C catalysts compared to alloyed PtSn x /C catalysts is attributed to the presence of both sufficiently large Pt ensembles for ethanol dehydrogenation and C-C bond splitting and of tin oxide for OH generation. Fuel cell measurements performed for comparison largely confirm the results obtained in model studies

  9. Exmination of catalytic reduction of NO by CH4 in a Pt-polybenimidazole membrane-Pt system with and without polarization

    Petrushina, Irina; Cleemann, Lars Nilausen; Bjerrum, Niels

    “NO reduction in the NO, CH4, Ar/Pt/C//polybenzimidazole-H3PO4//Pt/C/H2, Ar was studied at 135°C”......“NO reduction in the NO, CH4, Ar/Pt/C//polybenzimidazole-H3PO4//Pt/C/H2, Ar was studied at 135°C”...

  10. Corporate Governance in PT Lippo Karawaci Tbk

    Retno Kusumastuti

    2012-06-01

    Full Text Available When mismanagement and misuse run rampant in giant corporations, as in the case of Enron in 2001, good corporate governance becomes mandatory. From the perspective of the agency theory, the separation of capital owners and management must lead to strictly applied good corporate governance. The purpose is to eliminate any disadvantages to the corporation's objective, namely providing added values to all relevant parties. The agency theory also covers two aspects: agency issues and agency costs. The research uses the qualitative approach and data is gathered through extensive interview, secondary data, and bibliography study. Key persons among the sources are selected based on specific criteria. Data validity is obtained through the triangulation technique, and the samples used are PT Lippo Karawaci Tbk and subsidiaries. The results show that governance practices are unique in each corporation, in accordance with their characteristics.

  11. Spectroscopic ellipsometry study of FePt nanoparticle films

    Lee, S.J.; Lo, C.C.H. [Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Yu, A.C.C. [Sony Corporation, Sendai Technology Center, 3-4-1 Sakuragi, Miyagi 985-0842 (Japan); Fan, M. [School of Materials Science and Technology, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2006-12-15

    The optical properties of a FePt nanoparticle film were investigated using spectroscopic ellipsometry. The FePt nanoparticle film of thickness about 15 nm was prepared by deposition of FePt nanoparticles directly on a Si substrate. The nanoparticle film was annealed at 600 C in vacuum for two hours before the measurements. The optical properties of the FePt nanoparticle film showed distinctively different spectra from those obtained from the bulk and thin film FePt samples, in particular in the low photon energy range (below 3.5 eV) where the nanoparticle film exhibited a relatively flat refractive index and a substantially lower extinction coefficient than the bulk and epitaxial thin film samples. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Biofunctionalized ferromagnetic CoPt{sub 3}/polymer nanocomposites

    Martins, M A [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Neves, M C [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Esteves, A C C [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Girginova, P I [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Guiomar, A J [Department of Biochemistry and CNC, University of Coimbra, 3001-401 Coimbra (Portugal); Amaral, V S [Department of Physics, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Trindade, T [Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal)

    2007-05-30

    Magnetic latexes were prepared by the encapsulation of organically capped CoPt{sub 3} nanoparticles via miniemulsion in situ radical polymerization of tert-butyl acrylate (tBA). This is the first example of a CoPt{sub 3} based polymer nanocomposite showing ferromagnetic behaviour at room temperature. Each nanocomposite particle contains a magnetic core composed of CoPt{sub 3} nanoparticles (d{approx}7 nm, a{sub 0} = 3.848 A) encapsulated by poly(t-butyl acrylate). The CoPt{sub 3}/PtBA latexes contain polyester groups that can be readily hydrolysed, rendering the surface with carboxylic functionalities and hence allowing bioconjugation. Complementary to such surface modification experiments, we report that bovine IgG antibodies can bind to the magnetic latexes, and the potential of the nanocomposites for in vitro specific bioapplications is discussed.

  13. Pt coating on flame-generated carbon particles

    Choi, In Dae; Lee, Dong Geun

    2008-01-01

    Carbon black, activated carbon and carbon nanotube have been used as supporting materials for precious metal catalysts used in fuel cell electrodes. One-step flame synthesis method is used to coat 2-5nm Pt dots on flame-generated carbon particles. By adjusting flame temperature, gas flow rates and resident time of particles in flame, we can obtain Pt/C nano catalyst-support composite particles. Additional injection of hydrogen gas facilitates pyrolysis of Pt precursor in flame. The size of as-incepted Pt dots increases along the flame due to longer resident time and sintering in high temperature flame. Surface coverage and dispersion of the Pt dots is varied at different sampling heights and confirmed by Transmission Electron Microscopy (TEM), Energy Dispersive Spectra (EDS) and X-Ray Diffraction (XRD). Crystallinity and surface bonding groups of carbon are investigated through X-ray Photoelectron Spectroscoy (XPS) and Raman spectroscopy

  14. Fabrication of a nanosize-Pt-embedded membrane electrode assembly to enhance the utilization of Pt in proton exchange membrane fuel cells.

    Choe, Junseok; Kim, Doyoung; Shim, Jinyong; Lee, Inhae; Tak, Yongsug

    2011-08-01

    A procedure to locate the Pt nanostructure inside the hydrophilic channel of a Nafion membrane was developed in order to enhance Pt utilization in PEMFCs. Nanosize Pt-embedded MEA was constructed by Cu electroless plating and subsequent Pt electrodeposition inside the hydrophilic channels of the Nafion membrane. The metallic Pt nanostructure fabricated inside the membrane was employed as an oxygen reduction catalyst for a PEMFC and facilitated effective use of the hydrophilic channels inside the membrane. Compared to the conventional MEA, a Pt-embedded MEA with only 68% Pt loading showed better PEMFC performance.

  15. Magnetic phases in Pt/Co/Pt films induced by single and multiple femtosecond laser pulses

    Kisielewski, J., E-mail: jankis@uwb.edu.pl; Kurant, Z.; Sveklo, I.; Tekielak, M.; Maziewski, A. [Faculty of Physics, University of Białystok, Ciołkowskiego 1L, 15-245 Białystok (Poland); Wawro, A. [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw (Poland)

    2016-05-21

    Ultrathin Pt/Co/Pt trilayers with initial in-plane magnetization were irradiated with femtosecond laser pulses. In this way, an irreversible structural modification was introduced, which resulted in the creation of numerous pulse fluence-dependent magnetic phases. This was particularly true with the out-of-plane magnetization state, which exhibited a submicrometer domain structure. This effect was studied in a broad range of pulse fluences up to the point of ablation of the metallic films. In addition to this single-pulse experiment, multiple exposure spots were also investigated, which exhibited an extended area of out-of-plane magnetization phases and a decreased damage threshold. Using a double exposure with partially overlapped spots, a two-dimensional diagram of the magnetic phases as a function of the two energy densities was built, which showed a strong inequality between the first and second incoming pulses.

  16. Magnetic phases in Pt/Co/Pt films induced by single and multiple femtosecond laser pulses

    Kisielewski, J.; Kurant, Z.; Sveklo, I.; Tekielak, M.; Maziewski, A.; Wawro, A.

    2016-01-01

    Ultrathin Pt/Co/Pt trilayers with initial in-plane magnetization were irradiated with femtosecond laser pulses. In this way, an irreversible structural modification was introduced, which resulted in the creation of numerous pulse fluence-dependent magnetic phases. This was particularly true with the out-of-plane magnetization state, which exhibited a submicrometer domain structure. This effect was studied in a broad range of pulse fluences up to the point of ablation of the metallic films. In addition to this single-pulse experiment, multiple exposure spots were also investigated, which exhibited an extended area of out-of-plane magnetization phases and a decreased damage threshold. Using a double exposure with partially overlapped spots, a two-dimensional diagram of the magnetic phases as a function of the two energy densities was built, which showed a strong inequality between the first and second incoming pulses.

  17. Bimetallic Ag-Pt and Au-Pt aggregates synthesized by radiolysis

    Remita, S; Mostafavi, M; Delcourt, M O [Paris-11 Univ., 91 - Orsay (France)

    1996-02-01

    Irradiating aqueous solutions containing both Ag{sub 2}So{sub 4} and K{sub 2}PtCl{sub 4} leads to intermetallic aggregates of various sizes according to the stabilizing agent: polyvinylalcohol, polyacrylic acid or polyacrylate. In the last case, the particle diameter is 1.5 nm. The bimetallic character is evidenced in all cases by the spectral changes of such sols compared to pure silver sols which display a characteristic surface plasmon absorption band. This plasmon band disappears when 10 to 20 at.% or more Pr is present. Observation by TEM gives an estimation of the particle sizes. Comparable results have been obtained for Au-Pt particles. (author).

  18. Nitrogen availability of biogas residues

    El-Sayed Fouda, Sara

    2011-09-07

    The objectives of this study were to characterize biogas residues either unseparated or separated into a liquid and a solid phase from the fermentation of different substrates with respect to their N and C content. In addition, short and long term effects of the application of these biogas residues on the N availability and N utilization by ryegrass was investigated. It is concluded that unseparated or liquid separated biogas residues provide N at least corresponding to their ammonium content and that after the first fertilizer application the C{sub org}:N{sub org} ratio of the biogas residues was a crucial factor for the N availability. After long term application, the organic N accumulated in the soil leads to an increased release of N.

  19. A partial phase diagram of Pt-rich Pt-Mn alloys

    Sembiring, T; Ohshima, K I; Ota, K; Shishido, T

    2002-01-01

    We have performed the X-ray and electron diffraction studies to reconstruct a partial phase diagram of Pt-rich Pt-Mn alloys in the composition range of 10 to 35 at.% Mn. Electrical resistivity measurement was also used for determining the order-disorder transition temperature in Pt-14.2 at.% Mn alloy. The phase boundary between Cu sub 3 Au type and ABC sub 6 type ordered structures is established, in which the latter has been found recently by the present [J.Phys. Soc. Jpn. 71 (2002) 681]. In the ABC sub 6 type ordered phase, superlattice reflections both at 1/2 1/2 1/2 and its equivalent position (L-point) and at 100, 110 and their equivalent positions (X-point) appear in the composition range from 12.5 to 14.4 at.% Mn below 682degC. In the Cu sub 3 Au type ordered phase, diffuse maxima at L-point appear in the composition range from 15.9 to 19.7 at.% Mn in addition to the superlattice reflections at X-point. The Cu sub 3 Au type ordered structure is found to be stable in the composition range from 19.7 to 3...

  20. Electrochemical promotion of catalytic reactions with Pt/C (or Pt/Ru/C)//PBI catalysts

    Petrushina, Irina; Bjerrum, Niels; Bandur, Viktor

    2007-01-01

    The paper is an overview of the results of the investigation on electrochemical promotion of three catalytic reactions: methane oxidation with oxygen, NO reduction with hydrogen at 135 degrees C and Fischer-Tropsch synthesis (FTS) at 170 degrees C in the [CH4/O-2(or NO/H-2 or CO/H-2)/Ar//Pt(or Pt....../Ru)//PBI(H3PO4)/H-2, Ar] fuel cell. It has been shown that the partial methane oxidation to C2H2 and the C-2 selectivity were electrochemically promoted by the negative catalyst polarization. This was also the case in NO reduction with hydrogen for low NO and H-2 partial pressures. In both cases the catalytic...... reactions have been promoted by the electrochemically produced hydrogen. It has been found that the NO reduction with hydrogen on the Pt/PBI strongly depends on NO and hydrogen partial pressures in the working gas mixture. At higher NO and H-2 partial pressures the catalysis is promoted...

  1. Effect of hydrogen and propylene on the hydrogen peroxide decomposition over Pt, PtO and Au catalysts

    Kertalli, E.; Schouten, J.C.; Nijhuis, T.A.

    2017-01-01

    The decomposition of hydrogen peroxide (H2O2) on Pt, PtO and Au catalysts has been investigated in the presence of nitrogen, propylene and hydrogen. H2O2 formation on the catalyst is known to be a key intermediate step for the direct synthesis of propylene oxide (PO) from hydrogen, propylene and

  2. Unexpected, spontaneous and selective formation of colloidal Pt 3Sn nanoparticles using organometallic Pt and Sn complexes

    Boualleg, Malika; Baudouin, David; Basset, Jean-Marie; Bayard, Franç ois; Candy, Jean Pierre; Jumas, Jean Claude; Veyre, Laurent; Thieuleux, Chloé

    2010-01-01

    The facile and selective synthesis of small crystalline Pt3Sn alloy nanoparticles was performed at room temperature under H2, using a colloidal approach without the use of extra-stabilizing ligands. The Pt 3Sn alloy was found to be obtained

  3. Continuous Catalytic Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H-MFI-90

    Hellinger, Melanie; Baier, Sina; Mortensen, Peter Mølgaard

    2015-01-01

    Hydrodeoxygenation of guaiacol in the presence of 1-octanol was studied in a fixed-bed reactor under mild conditions (50–250 °C) over platinum particles supported on silica (Pt/SiO2) and a zeolite with framework type MFI at a Si/Al-ratio of 45 (Pt/H-MFI-90). The deoxygenation selectivity strongly...

  4. Methanol electro-oxidation on Pt-Ru-P/C and Pt-Ru-P/MWCNT in acidic medium

    Modibedi, M

    2009-06-01

    Full Text Available . The electro-catalytic activity towards methanol oxidation in acidic medium was studied by cyclic voltammetry and linear sweep voltammetry. Pt-Ru-P/MWCNT showed excellent activity compared to that of Pt-Ru-P/C. This may be attributed to the effectiveness...

  5. Stretching dependence of the vibration modes of a single-molecule Pt-H-2-Pt bridge

    Djukic, D.; Thygesen, Kristian Sommer; Untiedt, C.

    2005-01-01

    isotope substitution is obtained. The stretching dependence for each of the modes allows uniquely classifying them as longitudinal or transversal modes. The interpretation of the experiment in terms of a Pt-H-2-Pt bridge is verified by density-functional theory calculations for the stability, vibrational...

  6. Preparation of PtRu/Carbon hybrid materials by hydrothermal carbonization: A study of the Pt:Ru atomic ratio

    Tusi, Marcelo Marques; Brandalise, Michele; Correa, Olandir Vercino; Oliveira Neto, Almir; Linardi, Marcelo; Spinace, Estevam Vitorio; Villalba, Juan Carlo

    2009-01-01

    PtRu/Carbon materials with different Pt:Ru atomic ratios (30:70, 50:50, 60:40, 80:20 and 90:10) and 5 wt% of nominal metal load were prepared by hydrothermal carbonization using H 2 PtCl 6.6 H 2 O and RuCl 3. xH 2 O as metals sources and catalysts of the carbonization process and starch as carbon source and reducing agent. The obtained materials were treated at 900 deg C under argon and characterized by EDX, XRD and cyclic voltammetry. The electro-oxidation of methanol was studied by cyclic voltammetry and chronoamperometry using thin porous coating technique. The PtRu/Carbon materials showed Pt:Ru atomic ratios obtained by EDX similar to the nominal ones. XRD analysis showed that Pt face-cubic centered (FCC) and Ru hexagonal close-packed (HCP) phases coexist in the obtained materials. The average crystallite sizes of the Pt (FCC) phase were in the range of 8-12 nm. The material prepared with Pt:Ru atomic ratio of 50:50 showed the best performance for methanol electro-oxidation. (author)

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

    Chunguang Suo

    2014-03-01

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

  8. Reduction of NO adlayers on Pt(110) and Pt(111) in acidic media: evidence for adsorption site-specific reduction

    Rosca, V.; Beltramo, G.L.; Koper, M.T.M.

    2005-01-01

    We present a combined in situ Fourier transform infrared reflection-absorption spectroscopy and voltammetric study of the reduction of saturated and subsaturated NO adlayers on Pt(111) and Pt(110) single-crystal surfaces in acidic media. The stripping voltammetry experiments and the associated

  9. Opto-electronic properties of quasi-linear, self-assembled platinum complexes : Pt-Pt distance dependence

    Debije, M.G.; Haas, de M.P.; Warman, J.M.; Fontana, M.; Stutzmann, N.; Kristiansen, M.; Caseri, W.R.; Smith, P.; Hoffmann, S.; Solling, T. I.

    2004-01-01

    Charge-carrier mobilities of various self-assembled platinum complexes were measured by time-resolved microwave conductivity techniques in the temperature range –80 to +100¿°C. Eight compounds were investigated in the present study, including the original Magnus' green salt ([Pt(NH3)4][PtCl4]) and

  10. Unexpected, spontaneous and selective formation of colloidal Pt 3Sn nanoparticles using organometallic Pt and Sn complexes

    Boualleg, Malika

    2010-01-01

    The facile and selective synthesis of small crystalline Pt3Sn alloy nanoparticles was performed at room temperature under H2, using a colloidal approach without the use of extra-stabilizing ligands. The Pt 3Sn alloy was found to be obtained spontaneously as the unique phase regardless of the number of tin equivalents introduced. © 2010 The Royal Society of Chemistry.

  11. α-NiPt(Al) and phase equilibria in the Ni-Al-Pt system at 1150 deg C

    Hayashi, S.; Ford, S.I.; Young, D.J.; Sordelet, D.J.; Besser, M.F.; Gleeson, B.

    2005-01-01

    The α-NiPt(Al) phase and its associated equilibria in the Ni-Al-Pt system at 1150 deg C were investigated by analyzing equilibrated bulk alloys and the interdiffusion zones of diffusion couples. Phase constitutions, tie-lines and microstructures were determined using a combination of techniques, including high-energy synchrotron X-ray diffraction, scanning electron microscopy and electron probe microanalysis. A large Pt solubility limit was found to exist in the β-NiAl, ∼42 at.%, and in γ'-Ni 3 Al, ∼32 at.%. The α-NiPt(Al) phase was found to have wide Pt solubility range of about 33-60 at.% and to skew along an almost constant Pt/Al ratio of 1.5. The α-NiPt(Al) has an ordered face-centered tetragonal L1 0 crystal structure, with the Al and Pt atoms found to be preferentially located in the corners and prismatic faces, respectively. The temperature dependence of the lattice parameters and unit cell volume of the α phase were also determined

  12. Vesícula residual

    Júlio C. U. Coelho

    Full Text Available Our objective is to report three patients with recurrent severe upper abdominal pain secondary to residual gallbladder. All patients had been subjected to cholecystectomy from 1 to 20 years before. The diagnosis was established after several episodes of severe upper abdominal pain by imaging exams: ultrasonography, tomography, or endoscopic retrograde cholangiography. Removal of the residual gallbladder led to complete resolution of symptoms. Partial removal of the gallbladder is a very rare cause of postcholecystectomy symptoms.

  13. Residual number processing in dyscalculia ?

    Cappelletti, Marinella; Price, Cathy J.

    2013-01-01

    Developmental dyscalculia – a congenital learning disability in understanding numerical concepts – is typically associated with parietal lobe abnormality. However, people with dyscalculia often retain some residual numerical abilities, reported in studies that otherwise focused on abnormalities in the dyscalculic brain. Here we took a different perspective by focusing on brain regions that support residual number processing in dyscalculia. All participants accurately performed semantic and ca...

  14. Americium recovery from reduction residues

    Conner, W.V.; Proctor, S.G.

    1973-12-25

    A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)

  15. Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

    Bernay Cifuentes

    2015-11-01

    Full Text Available CeO2-, ZrO2-, and La2O3-supported Rh-Pt catalysts were tested to assess their ability to catalyze the steam reforming of ethanol (SRE for H2 production. SRE activity tests were performed using EtOH:H2O:N2 (molar ratio 1:3:51 at a gaseous space velocity of 70,600 h−1 between 400 and 700 °C at atmospheric pressure. The SRE stability of the catalysts was tested at 700 °C for 27 h time on stream under the same conditions. RhPt/CeO2, which showed the best performance in the stability test, also produced the highest H2 yield above 600 °C, followed by RhPt/La2O3 and RhPt/ZrO2. The fresh and aged catalysts were characterized by TEM, XPS, and TGA. The higher H2 selectivity of RhPt/CeO2 was ascribed to the formation of small (~5 nm and stable particles probably consistent of Rh-Pt alloys with a Pt surface enrichment. Both metals were oxidized and acted as an almost constant active phase during the stability test owing to strong metal-support interactions, as well as the superior oxygen mobility of the support. The TGA results confirmed the absence of carbonaceous residues in all the aged catalysts.

  16. Improving the stability and ethanol electro-oxidation activity of Pt catalysts by selectively anchoring Pt particles on carbon-nanotubes-supported-SnO{sub 2}

    Li, J.J.; Wang, J.S.; Zhao, J.H.; Song, C.Y.; Wang, L.C. [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou (China); Guo, X. [Department of Chemistry, Tsinghua University, Beijing (China)

    2012-10-15

    To improve the stability and activity of Pt catalysts for ethanol electro-oxidation, Pt nanoparticles were selectively deposited on carbon-nanotubes (CNTs)-supported-SnO{sub 2} to prepare Pt/SnO{sub 2}/CNTs and Pt/CNTs was prepared by impregnation method for reference study. X-ray diffraction (XRD) was used to confirm the crystalline structures of Pt/SnO{sub 2}/CNTs and Pt/CNTs. The stabilities of Pt/SnO{sub 2}/CNTs and Pt/CNTs were compared by analyzing the Pt size increase amplitude using transmission electron microscopy (TEM) images recorded before and after cyclic voltammetry (CV) sweeping. The results showed that the Pt size increase amplitude is evidently smaller for Pt/SnO{sub 2}/CNTs, indicating the higher stability of Pt/SnO{sub 2}/CNTs. Although both catalysts exhibit degradation of electrochemical active surface area (EAS) after CV sweeping, the EAS degradation for the former is lower, further confirming the higher stability of Pt/SnO{sub 2}/CNTs. CV and potentiostatic current-time curves were recorded for ethanol electro-oxidation on both catalysts before and after CV sweeping and the results showed that the mass specific activity of Pt/CNTs increases more than that of Pt/SnO{sub 2}/CNTs, indicating that Pt/CNTs experiences more severe evolution and is less stable. The calculated area specific activity of Pt/SnO{sub 2}/CNTs is larger than that of Pt/CNTs, indicating SnO{sub 2} can co-catalyze Pt due to plenty of interfaces between SnO{sub 2} and Pt. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Work session on the SAR. Pt. 1

    Burkart, K.

    1980-01-01

    In the first part of the present paper, containment isolation, pressurizer systems, valves of coolant systems and volume control systems are described. In the second part residual heat removal systems and the water-steam cycle are dealt with. Then initiation criteria and safety actions as well as malfunctions in the feedwater supply are discussed and finally leakages from the pressurized boundary of the reactor cooling system due to ruptures in connection lines and valve malfunction are considered. (RW)

  18. Pt, Re and Pt-Re incorporation in sulfated zirconia as catalysts for n-pentane isomerization

    Aboul-Gheit, A.K.; El-Desouki, D.S.; Abdel-Hamid, S.M.; Ghoneim, S.A.; Ibrahim, A.H.; Gad, F.K.; Abdel-Aleem, G.M.

    2010-01-01

    Two groups of modified Sulfated Zirconia (S Z) catalysts were prepared by the sol-gel method. The first group was modified by four different concentrations of Pt metal (0.15, 0.30, 0.45 and 0.60 wt %), whereas the second group contained Pt-Re combinations on SZ. All the prepared catalysts were characterized by XRD, TPR, TEM, TGA, IR spectroscopy as well as surface properties using the BET method. The catalytic activity of the catalysts was examined for the hydro isomerization of n-pentane to iso-pentane. The catalytic activity was found to increase with increasing Pt concentration in the mono metallic catalysts. The combination of Re ion with Pt on SZ results in significant changes in the characters and activities of the catalysts. The 0.45 wt % Pt + 0.15 wt % Re/SZ catalyst exhibited the highest selective compared to other metal ratios investigated

  19. New evaluation of alpha decay half-life of 190Pt isotope for the Pt-Os dating system

    Tavares, O.A.P.; Medeiros, E.L.; Terranova, M.L.

    2005-08-01

    A semiempirical model based on the quantum mechanical tunnelling mechanism of alpha emission from nuclei has been used to evaluate the half-life of the Pt isotopes. For the important naturally occurring 190 Pt isotope, the radiogenic parent in the 190 Pt → 186 Os dating system, the model yielded a half-life value of (3.7± 0.3) versus 10 11 y. This is comparable to (3.2±0.1) versus 10 11 y which was obtained in the last direct counting experiment to measure the alpha activity of 190 Pt (Tavares and Terranova, Rad. Measurem. 27 (1997) 19). A literature survey of available alpha decay half-life values for 190 Pt isotope is also reported. The significant discrepancies found between data obtained by direct counting, indirect geological methods and different calculation models are analysed and discussed. (author)

  20. Synthesis of Ag or Pt Nanoparticles by Hydrolysis of Either Ag2Na or PtNa

    Huabin Wang

    2008-01-01

    Full Text Available Ag and Pt nanoparticles have successfully been synthesized by hydrolysis of either Ag2Na or PtNa at room temperature. The oxidation of sodium in the Pt-Na pellets was much faster than that in the Ag-Na pellets since Pt is a catalyst for H2O formation reaction from hydrogen and oxygen at room temperature. The hydrolysis byproduct, NaOH, has a high solubility and easily is removed. This method offers a simple method of preparing transition metal nanoparticles. The Ag and Pt nanoparticles prepared by this method were crystalline in nature, and spherical in shape with a mean size of around 10 nm.

  1. Correlating Structure and Oxygen Reduction Activity on Y/Pt(111) and Gd/Pt(111) Single Crystals

    Ulrikkeholm, Elisabeth Therese; Pedersen, Anders Filsøe; Johansson, Tobias Peter

    2015-01-01

    Polymer Electrolyte Membrane Fuel Cells (PEMFC) hold promise as a zero-emission source of power, particularly suitable for automotive vehicles. However, the high loading of Pt required to catalyse the Oxygen Reduction Reaction (ORR) at the PEMFC cathode prevents the commercialisation of this tech......Polymer Electrolyte Membrane Fuel Cells (PEMFC) hold promise as a zero-emission source of power, particularly suitable for automotive vehicles. However, the high loading of Pt required to catalyse the Oxygen Reduction Reaction (ORR) at the PEMFC cathode prevents the commercialisation...... of this technology. Improving the activity of Pt by alloying it with other metals could decrease the loading of Pt at the cathode to a level comparable to Pt-group metal loading in internal combustion engines. PtxY and PtxGd exhibit exceptionally high activity for oxygen reduction, both in the polycrystalline form...

  2. The kinetics and mechanism of methanol oxidation on Pt and PtRu catalysts in alkaline and acid media

    JELENA LOVIC

    2007-07-01

    Full Text Available The kinetic of methanol electrochemical oxidation for a series of platinum and platinum–ruthenium catalysts was investigated. A correlation between the beginning of OHad adsorption and methanol oxidation was demonstarated on Pt single crystals and Pt nanocatalyst. The activity of the nano-structured Pt catalyst was compared with single crystal platinum electrodes assuming the Kinoshita model of nanoparticles. The ruthenium-containing catalysts shifted the onset of methanol oxidation to more negative potentials. The effect was more pronounced in acid than in alkaline media. Based on the established diagnostic criteria, the reaction between COad and OHad species according to the Langmuir–Hinshelwood mechanism was proposed as the rate determining step in alkaline and acid media on Pt and PtRu catalysts.

  3. Exchange bias and perpendicular anisotropy study of ultrathin Pt-Co-Pt-IrMn multilayers sputtered on float glass

    Laval, M.; Lüders, U.; Bobo, J. F.

    2007-09-01

    We have prepared ultrathin Pt-Co-Pt-IrMn polycrystalline multilayers on float-glass substrates by DC magnetron sputtering. We have determined the optimal set of thickness for both Pt layers, the Co layer and the IrMn biasing layer so that these samples exhibit at the same time out-of-plane magnetic anisotropy and exchange bias. Kerr microscopy domain structure imaging evidences an increase of nucleation rate accompanied with inhomogeneous magnetic behavior in the case of exchange-biased films compared to Pt-Co-Pt trilayers. Polar hysteresis loops are measured in obliquely applied magnetic field conditions, allowing us to determine both perpendicular anisotropy effective constant Keff and exchange-bias coupling JE, which are significantly different from the ones determined by standard switching field measurements.

  4. Exchange bias and perpendicular anisotropy study of ultrathin Pt-Co-Pt-IrMn multilayers sputtered on float glass

    Laval, M.; Lueders, U.; Bobo, J.F.

    2007-01-01

    We have prepared ultrathin Pt-Co-Pt-IrMn polycrystalline multilayers on float-glass substrates by DC magnetron sputtering. We have determined the optimal set of thickness for both Pt layers, the Co layer and the IrMn biasing layer so that these samples exhibit at the same time out-of-plane magnetic anisotropy and exchange bias. Kerr microscopy domain structure imaging evidences an increase of nucleation rate accompanied with inhomogeneous magnetic behavior in the case of exchange-biased films compared to Pt-Co-Pt trilayers. Polar hysteresis loops are measured in obliquely applied magnetic field conditions, allowing us to determine both perpendicular anisotropy effective constant K eff and exchange-bias coupling J E , which are significantly different from the ones determined by standard switching field measurements

  5. Evidence of surface migration and formation of catalytically inactive Pt in corrosion studies of Pt+ implanted Ti

    Appleton, B.R.; Kelly, E.J.; White, C.W.; Thompson, N.G.; Lichter, B.D.

    1980-08-01

    This investigation is part of an ongoing research project directed at applying the techniques of ion implantation doping and ion scattering analysis to identify the mechanisms associated with the anodic dissolution of Ti-Pt alloys. The Ti-Pt alloys produced by ion implantation were electrochemically examined in hydrogen saturated 1 N H 2 SO 4 by both potentiostatic polarization and open-circuit potential methods. In this study, Ti samples implanted to relatively high doses (5.4 x 10 15 to 2.9 x 10 16 atoms/cm 2 ) were examined by ion scattering analysis at various stages in the electrochemical measurements. Quantitative measurements showed that the majority of the implanted Pt accumulated on the surface during anodic dissolution and underwent large scale surface migration. Evidence is also presented for the transition of the Pt on the surface from a catalytically active to inactive state. Possible mechanisms for the observed catalytically inactive Pt are discussed

  6. Catalytic Hydrogenation and Hydrodeoxygenation of Furfural over Pt(111): A Model System for the Rational Design and Operation of Practical Biomass Conversion Catalysts.

    Taylor, Martin J; Jiang, Li; Reichert, Joachim; Papageorgiou, Anthoula C; Beaumont, Simon K; Wilson, Karen; Lee, Adam F; Barth, Johannes V; Kyriakou, Georgios

    2017-04-20

    Furfural is a key bioderived platform chemical whose reactivity under hydrogen atmospheres affords diverse chemical intermediates. Here, temperature-programmed reaction spectrometry and complementary scanning tunneling microscopy (STM) are employed to investigate furfural adsorption and reactivity over a Pt(111) model catalyst. Furfural decarbonylation to furan is highly sensitive to reaction conditions, in particular, surface crowding and associated changes in the adsorption geometry: furfural adopts a planar geometry on clean Pt(111) at low coverage, tilting at higher coverage to form a densely packed furfural adlayer. This switch in adsorption geometry strongly influences product selectivity. STM reveals the formation of hydrogen-bonded networks for planar furfural, which favor decarbonylation on clean Pt(111) and hydrogenolysis in the presence of coadsorbed hydrogen. Preadsorbed hydrogen promotes furfural hydrogenation to furfuryl alcohol and its subsequent hydrogenolysis to methyl furan, while suppressing residual surface carbon. Furfural chemistry over Pt is markedly different from that over Pd, with weaker adsorption over the former affording a simpler product distribution than the latter; Pd catalyzes a wider range of chemistry, including ring-opening to form propene. Insight into the role of molecular orientation in controlling product selectivity will guide the design and operation of more selective and stable Pt catalysts for furfural hydrogenation.

  7. Solid-state phase equilibria in the Fe-Pt-Pr ternary system at 1173 K

    Ren Jing; Gu Zhengfei; Cheng Gang; Zhou Huaiying

    2005-01-01

    The solid-state phase equilibria in the Fe-Pt-Pr ternary system at 1173 K (Pr ≤ 70%) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. The 1173 K isothermal section consists of 13 single-phase regions, 22 two-phase regions and 10 three-phase regions. At 1173 K, we have observed that the maximum solid solubility of Pt in α-Fe is below 1.5 at.% and the solid solution region of Pt in γ-Fe is from 2 to 35 at.%; the maximum solid solubility of Fe in Pt is 18 at.%. The maximum solubility of Fe in PrPt 5 , PrPt 3 , PrPt 2 , Pr 3 Pt 4 , PrPt, Pr 3 Pt 2 and Pr 7 Pt 3 is below 1 at.%. The maximum solubility of Pr in α-(Fe, Pt), γ-(Fe, Pt), FePt, FePt 3 and (Pt, Fe) (the solid solution of Fe in Pt) is 6, 2, 4, 4.5 and 1.5 at.%, respectively. In this work, it is found that the phase Pr 3 Pt 4 does not exist in the ternary system. The binary compounds Fe 7 Pr and Fe 2 Pr and any new ternary compounds were not observed

  8. Pt and PtRu nanoparticles supported on N-doped carbons as electrocatalysts for methanol electro oxidation

    Pereira, Viviane Santos; Silva, Julio Cesar Martins; Oliveira Neto, Almir; Spinace, Estevam Vitorio, E-mail: viviane_sp_saopaulo@yahoo.com.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2016-07-01

    Full text: Methanol is a liquid transportation fuel that can be produced from fossil or renewable resources. Fuel cells employing methanol directly as fuel (Direct Methanol Fuel Cell - DMFC) are very attractive as power source for portable, mobile and stationary applications [1]. PtRu/C electrocatalyst has been considered the best electrocatalyst for methanol electro-oxidation, however, its performance is strongly dependent on the method of preparation and on the characteristics of the carbon support. N-doped carbons with different N contents (1, 2 and 5 wt%) were prepared by thermal treatment of carbon with urea at 800 deg C. Pt and PtRu nanoparticles were supported on N-doped carbons by coreduction of Pt(IV) and Ru(III) ions using an alcohol-reduction process [2]. The obtained materials were characterized by Energy Dispersive X-ray spectroscopy, X-ray diffraction, Transmission electron microscopy and Cyclic Voltammetry. Pt and PtRu nanoparticles supported on N-doped carbons showed superior performance for methanol electro-oxidation when compared to the materials supported on non-modified carbon and to Pt/C and PtRu/C commercial electrocatalysts. Pt/C and PtRu/C prepared with the carbon modified with 2.5 wt% of N content showed the best activities. (author) [1] Y. Zhou, K. Neyerlin, T.S. Olson, S. Pylypenko, J. Bult, H.N. Dinh, T. Gennett, Z. Shao and R. O'Hayre, Energy Environ. Sci. 3, 1437 (2010); [2] E.V. Spinace, A.Oliveira Neto, T.R.R. Vasconcellos, M. Linardi, J. Power Sources 137, 17 (2004)

  9. Evaluation of residue-residue contact prediction in CASP10

    Monastyrskyy, Bohdan

    2013-08-31

    We present the results of the assessment of the intramolecular residue-residue contact predictions from 26 prediction groups participating in the 10th round of the CASP experiment. The most recently developed direct coupling analysis methods did not take part in the experiment likely because they require a very deep sequence alignment not available for any of the 114 CASP10 targets. The performance of contact prediction methods was evaluated with the measures used in previous CASPs (i.e., prediction accuracy and the difference between the distribution of the predicted contacts and that of all pairs of residues in the target protein), as well as new measures, such as the Matthews correlation coefficient, the area under the precision-recall curve and the ranks of the first correctly and incorrectly predicted contact. We also evaluated the ability to detect interdomain contacts and tested whether the difficulty of predicting contacts depends upon the protein length and the depth of the family sequence alignment. The analyses were carried out on the target domains for which structural homologs did not exist or were difficult to identify. The evaluation was performed for all types of contacts (short, medium, and long-range), with emphasis placed on long-range contacts, i.e. those involving residues separated by at least 24 residues along the sequence. The assessment suggests that the best CASP10 contact prediction methods perform at approximately the same level, and comparably to those participating in CASP9.

  10. Modelling and analysis of the stress distribution in a multi-thin film system Pt/USG/Si

    Yao, W. Z.; Roqueta, F.; Craveur, J. C.; Belhenini, S.; Gardes, P.; Tougui, A.

    2018-04-01

    Residual stress analysis is commonly achieved through curvature measurement with the help of Stoney’s formula. However, this conventional approach is inadequate for multi-layer thin film systems, which are widely used in today’s microelectronics. Also, for the thin film case, the residual stress is composed of thermal stress and intrinsic stress. Measuring the wafer curvature at room temperature provides a value for the average stresses in the layer, the two components cannot be distinguished by the existing methodologies of curvature measurement. To alleviate these problems, a modified curvature method combining finite element (FE) modelling is proposed to study the stress distribution in a Pt/USG/Si structure. A 2D FE model is firstly built in order to calculate the thermal stress in the multilayer structure, the obtained thermal stresses in respective films are verified by an analytical model. Then, we calculate the warpage of the multilayer structure by considering the intrinsic stress in the respective films. The residual stresses in the films are determined by minimizing the difference between the simulated warpage and that of experimental measurement. The proposed approach can be used to calculate not only the average residual stress but also thermal and intrinsic stress components in the USG and Platinum films. The obtained residual and intrinsic stresses from a numerical model are compared with the values of other studies. There is no limitation for the application of our methodologies regarding the number of the layers in the stack.

  11. H2O on Pt(111): structure and stability of the first wetting layer

    Standop, Sebastian; Michely, Thomas; Busse, Carsten; Morgenstern, Markus

    2012-01-01

    We study the structure and stability of the first water layer on Pt(111) by variable-temperature scanning tunneling microscopy. We find that a high Pt step edge density considerably increases the long-range order of the equilibrium √(37)×√(37)R25.3°- and √(39)×√(39)R16.1°-superstructures, presumably due to the capability of step edges to trap residual adsorbates from the surface. Passivating the step edges with CO or preparing a flat metal surface leads to the formation of disordered structures, which still show the same structural elements as the ordered ones. Coadsorption of Xe and CO proves that the water layer covers the metal surface completely. Moreover, we determine the two-dimensional crystal structure of Xe on top of the chemisorbed water layer which exhibits an Xe-Xe distance close to the one in bulk Xe and a rotation angle of 90° between the close-packed directions of Xe and the close-packed directions of the underlying water layer. CO is shown to replace H 2 O on the Pt(111) surface as has been deduced previously. In addition, we demonstrate that tunneling of electrons into the antibonding state or from the bonding state of H 2 O leads to dissociation of the molecules and a corresponding reordering of the adlayer into a √3×√3R30°-structure. Finally, a so far not understood restructuring of the adlayer by an increased tunneling current has been observed. (paper)

  12. Doping characteristics of iodine on as-grown chemical vapor deposited graphene on Pt

    Kim, HoKwon, E-mail: hknano@gmail.com [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Renault, Olivier [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Tyurnina, Anastasia; Guillet, Jean-François; Simonato, Jean-Pierre [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LITEN/DTMN, F-38054 Grenoble (France); Rouchon, Denis; Mariolle, Denis; Chevalier, Nicolas [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Dijon, Jean [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LITEN/DTMN, F-38054 Grenoble (France)

    2015-12-15

    Using laboratory X-ray photoelectron emission microscopy (XPEEM), we investigated the doping efficiency and thermal stability of iodine on as-grown graphene on Pt. After iodine adsorption of graphene in saturated vapor of I{sub 2,} monolayer and bilayer graphene exhibited work function of 4.93 eV and 4.87 eV, respectively. Annealing of the doped monolayer graphene at 100 °C led to desorption of hydrocarbons, which increased the work function of monolayer graphene by ~0.2 eV. The composition of the polyiodide complexes evolved upon a step-by-step annealing at temperatures from 100 °C to 300 °C while the work-function non-monotonically changed with decreasing iodine content. The iodine dopant was stable at relatively high temperature as a significant amount of iodine remained up to the annealing temperature of 350 °C. - Highlights: • Laboratory XPEEM demonstrates that iodine can effectively p-dope as-grown graphene on Pt with a work-function value up to 5.1 eV. • On the other hand, residual hydrocarbon contamination decreases the work function by up to ~0.2 eV. • The spontaneous intercalation of as-grown few-layered graphene is not easily feasible. • The iodine dopant was not completely removed up to the annealing temperature of 350 °C. • The I{sub 3}{sup −} and I{sub 5}{sup −} polyiodide content ratio of I-doped Gr/Pt decreases with annealing temperature.

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

    Josef C. Meier

    2014-01-01

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

  14. Effects of Cr underlayer and Pt buffer layer on the interfacial structure and magnetic characteristics of sputtered FePt films

    Sun, A.-C.; Hsu, J.-H.; Huang, H.L.; Kuo, P.C.

    2006-01-01

    This work develops a new method for growing L1 0 FePt(0 0 1) thin film on a Pt/Cr bilayer using an amorphous glass substrate. Semi-coherent epitaxial growth was initiated from the Cr(0 0 2) underlayer, continued through the Pt(0 0 1) buffer layer, and extended into the L1 0 FePt(0 0 1) magnetic layer. The squareness of the L1 0 FePt film in the presence of both a Cr underlayer and a Pt buffer layer was close to unity as the magnetic field was applied perpendicular to the film plane. The single L1 0 FePt(1 1 1) orientation was observed in the absence of a Cr underlayer. When a Cr underlayer is inserted, the preferred orientation switched from L1 0 FePt(1 1 1) to L1 0 FePt(0 0 1) and the magnetic film exhibited perpendicular magnetic anisotropy. However, in the absence of an Pt intermediate layer, the Cr atoms diffused directly into the FePt magnetic layer and prevented the formation of the L1 0 FePt(0 0 1) preferred orientation. When a Pt buffer layer was introduced between the FePt and Cr underlayer, the L1 0 FePt(0 0 1) peak appeared. The thickness of the Pt buffer layer also substantially affected the magnetic properties and atomic arrangement at the FePt/Pt and Pt/Cr interfaces

  15. Electro-oxidation of methanol and ethanol using PtRu/C, PtSn/C and PtSnRu/C electrocatalysts prepared by an alcohol-reduction process

    Neto, Almir Oliveira; Dias, Ricardo R.; Tusi, Marcelo M.; Linardi, Marcelo; Spinace, Estevam V. [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes 2242, Cidade Universitaria, CEP 05508-900 Sao Paulo, SP (Brazil)

    2007-03-30

    PtRu/C, PtSn/C and PtSnRu/C electrocatalysts were prepared by the alcohol reduction process using ethylene glycol as the solvent and reduction agent and Vulcan Carbon XC72 as the support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry. The electrochemical oxidation of methanol and ethanol were studied by chronoamperometry using a thin porous coating technique. The PtSn/C electrocatalyst prepared by this methodology showed superior performance compared to the PtRu/C and PtSnRu/C electrocatalysts for methanol and ethanol oxidation at room temperature. (author)

  16. Electro-oxidation of methanol and ethanol using PtRu/C, PtSn/C and PtSnRu/C electrocatalysts prepared by an alcohol-reduction process

    Neto, Almir Oliveira; Dias, Ricardo R.; Tusi, Marcelo M.; Linardi, Marcelo; Spinacé, Estevam V.

    PtRu/C, PtSn/C and PtSnRu/C electrocatalysts were prepared by the alcohol reduction process using ethylene glycol as the solvent and reduction agent and Vulcan Carbon XC72 as the support. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry. The electrochemical oxidation of methanol and ethanol were studied by chronoamperometry using a thin porous coating technique. The PtSn/C electrocatalyst prepared by this methodology showed superior performance compared to the PtRu/C and PtSnRu/C electrocatalysts for methanol and ethanol oxidation at room temperature.

  17. Pt(IV) complexes as prodrugs for cisplatin.

    Shi, Yi; Liu, Shu-An; Kerwood, Deborah J; Goodisman, Jerry; Dabrowiak, James C

    2012-02-01

    The antitumor effects of platinum(IV) complexes, considered prodrugs for cisplatin, are believed to be due to biological reduction of Pt(IV) to Pt(II), with the reduction products binding to DNA and other cellular targets. In this work we used pBR322 DNA to capture the products of reduction of oxoplatin, c,t,c-[PtCl(2)(OH)(2)(NH(3))(2)], 3, and a carboxylate-modified analog, c,t,c-[PtCl(2)(OH)(O(2)CCH(2)CH(2)CO(2)H)(NH(3))(2)], 4, by ascorbic acid (AsA) or glutathione (GSH). Since carbonate plays a significant role in the speciation of platinum complexes in solution, we also investigated the effects of carbonate on the reduction/DNA-binding process. In pH 7.4 buffer in the absence of carbonate, both 3 and 4 are reduced by AsA to cisplatin (confirmed using ((195))Pt NMR), which binds to and unwinds closed circular DNA in a manner consistent with the formation of the well-known 1, 2 intrastrand DNA crosslink. However, when GSH is used as the reducing agent for 3 and 4, ((195))Pt NMR shows that cisplatin is not produced in the reaction medium. Although the Pt(II) products bind to closed circular DNA, their effect on the mobility of Form I DNA is different from that produced by cisplatin. When physiological carbonate is present in the reduction medium, ((13))C NMR shows that Pt(II) carbonato complexes form which block or impede platinum binding to DNA. The results of the study vis-à-vis the ability of the Pt(IV) complexes to act as prodrugs for cisplatin are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. STRATEGI PENGEMBANGAN KEMITRAAN TERNAK AYAM BROILER PT. XYZ

    Latifa Hanum

    2011-11-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} The objectives of this research are to (1 analyze profit and BEP of plasma farmers (2 analyze internal and external strategic factors that influence development of broiler partnership in PT. XYZ, (3 formulate the alternative strategies of broiler partnership in PT. XYZ, (4 formulate selected priority strategy to develop broiler partnership in PT. XYZ. This research uses descriptive method based on case study on broiler partnership in PT. XYZ. Based on BEP analysis, BEP (production of plasma farmers is in the range 79,91%-86,58% from chick-in capacity, and BEP (price is in the range of Rp 11.684 – Rp 12.191 per chicken on market price. PT. XYZ partnership’s position in IE matric was second quadrant (grow and builds. The results of SWOT analysis are: a vertical integration strategy through feedmill, breeding and chicken slaughterhouse, b improving production capacity through capacity building of plasma farmers, c improvement in bio-security aspects of maintenance, and d improving the quality of technical staff and improving supervision. The priority strategy from QSPM analysis is improving production capacity through capacity building of plasma farmers. The strategy to improve production capacity can be done by maximize or add their capacity, and add the new plasma farmers.   Keywords: Broiler Partnership, Internal Environment, External Environment, Internal-external, Improvement Priority

  19. EVALUASI SISTEM PENGELOLAAN LIMBAH PADAT B3 PT. INDOFARMA, TBK BEKASI

    Syafrudin Syafrudin

    2012-02-01

    Full Text Available Besides yielding product, production process also will yield discard product that we called as waste. Thetype of the waste are depended on the raw materials and other process that happened during theproduction process. As a pharmacy industry, PT. Indofarma Tbk also generate waste from their productionprocess which have potency to contaminate the environment because the most material that use for theproduction are chemicals that need to be handled seriously. The waste can be categorize as HazardousWaste and needed furthermore management to control, so it will be secure for the environment. Forpharmacy industry, the hazardous waste is in the form of the chemicals, Waste Water Treatment’s sludge,residu production process like dust from dust collector, incinerator’s fly ash, and other materials which iscame from hazardous materials.

  20. Early-stage ordering in in-situ annealed Fe51Pt49 films

    Hsiao, S.N.; Chen, S.K.; Chin, T.S.; Hsu, Y.W.; Huang, H.W.; Yuan, F.T.; Lee, H.Y.; Liao, W.M.

    2009-01-01

    We evidenced an early-stage ordering (ESO) in Fe 51 Pt 49 film before the appearance of superlattice diffraction (long-range-order, LRO) using 40-nm-thick films prepared by magnetron sputtering onto quartz substrate. The appearance of L1 0 phase for samples deposited at substrate temperatures (T s ) 400 deg. C and higher was verified by X-ray diffraction. Surface roughness of Fe 51 Pt 49 films, obtained via X-ray specular reflectivity with computational fitting, increases from 3.8 to 11 A as T s is increased from 25 to 275 deg. C. As further increase of T s to 375 deg. C, the roughness drops to 3.2 A and then increases again to 38 A with T s up to 700 deg. C. Measurement on residual strain demonstrates that it is initially compressive at T s s up to 700 deg. C corresponding to LRO transformation. Local atomic rearrangement is observed for samples deposited at T s >250 deg. C by using extended X-ray absorption fine structure. Coercivity of films increases from 10 to 460 Oe as T s increase from 25 to 375 deg. C (ESO) and then from 460 to 10,700 Oe with T s 375-700 deg. C (normal LRO). The worked out quantitative estimation of ESO engages with that of LRO before T s 400 deg. C.

  1. Catalytically favorable surface patterns in Pt-Au nanoclusters

    Mokkath, Junais Habeeb

    2013-01-01

    Motivated by recent experimental demonstrations of novel PtAu nanoparticles with highly enhanced catalytic properties, we present a systematic theoretical study that explores principal catalytic indicators as a function of the particle size and composition. We find that Pt electronic states in the vicinity of the Fermi level combined with a modified electron distribution in the nanoparticle due to Pt-to-Au charge transfer are the origin of the outstanding catalytic properties. From our model we deduce the catalytically favorable surface patterns that induce ensemble and ligand effects. © The Royal Society of Chemistry 2013.

  2. Residual stresses around Vickers indents

    Pajares, A.; Guiberteau, F.; Steinbrech, R.W.

    1995-01-01

    The residual stresses generated by Vickers indentation in brittle materials and their changes due to annealing and surface removal were studied in 4 mol% yttria partially stabilized zirconia (4Y-PSZ). Three experimental methods to gain information about the residual stress field were applied: (i) crack profile measurements based on serial sectioning, (ii) controlled crack propagation in post indentation bending tests and (iii) double indentation tests with smaller secondary indents located around a larger primary impression. Three zones of different residual stress behavior are deduced from the experiments. Beneath the impression a crack free spherical zone of high hydrostatic stresses exists. This core zone is followed by a transition regime where indentation cracks develop but still experience hydrostatic stresses. Finally, in an outward third zone, the crack contour is entirely governed by the tensile residual stress intensity (elastically deformed region). Annealing and surface removal reduce this crack driving stress intensity. The specific changes of the residual stresses due to the post indentation treatments are described and discussed in detail for the three zones

  3. Minimization of zirconium chlorinator residues

    Green, G.K.; Harbuck, D.D.

    1995-01-01

    Zirconium chlorinator residues contain an array of rare earths, scandium, unreacted coke, and radioactive thorium and radium. Because of the radioactivity, the residues must be disposed in special waste containment facilities. As these sites become more congested, and with stricter environmental regulations, disposal of large volumes of wastes may become more difficult. To reduce the mass of disposed material, the US Bureau of Mines (USBM) developed technology to recover rare earths, thorium and radium, and unreacted coke from these residues. This technology employs an HCl leach to solubilize over 99% of the scandium and thorium, and over 90% of the rare earths. The leach liquor is processed through several solvent extraction stages to selectively recover scandium, thorium, and rare earths. The leach residue is further leached with an organic acid to solubilize radium, thus allowing unreacted coke to be recycled to the chlorinator. The thorium and radium waste products, which comprise only 2.1% of the original residue mass, can then be sent to the radioactive waste facility

  4. Structural properties of Pt/TiO{sub 2}/Pt heterostructure grown on sapphire substrate—Influence of annealing processes

    Roch, Tomas, E-mail: roch@fmph.uniba.sk; Durina, Pavol; Grancic, Branislav; Gregor, Maros; Plecenik, Tomas; Truchly, Martin; Mikula, Marian; Satrapinskyy, Leonid; Kus, Peter; Plecenik, Andrej

    2014-09-01

    Highlights: • Pt/TiO{sub 2}/Pt, Pt/TiO{sub 2} and TiO{sub 2}/Pt stacks were grown on (c-cut) Al{sub 2}O{sub 3} and annealed at 600 °C. • Pt/TiO{sub 2}/Pt contains both TiO{sub 2}-anatase (27%) and rutile (73%) phases after annealing. • Pt/TiO{sub 2} contains both anatase and rutile, TiO{sub 2}/Pt anatase phase only. • Epitaxial relationship of bottom platinum: Pt(1 1 1)[1–10]||sub(0 0 0 1)[11{sup ¯}00]. • Platinum top layer is uniaxially oriented: Pt(1 1 1)||sub(0 0 0 1). - Abstract: Simple gas sensors based on resistivity change of TiO{sub 2} thin films using combined top and bottom metallic contacts are very promising. In this work influence of ex situ annealing in ambient air on structure of TiO{sub 2} thin film stacked between two platinum contact layers has been studied. The layers were deposited using DC magnetron sputtering on unheated c-cut sapphire substrates. For lowering of the Schottky barrier at the Pt–TiO{sub 2} interfaces and for improved crystalline stability, ex situ annealing at 600 °C in air was carried out. In order to study separately influence of top and bottom platinum layers on crystal structure, also reference samples Pt/TiO{sub 2}/Al{sub 2}O{sub 3} and TiO{sub 2}/Pt/Al{sub 2}O{sub 3} have been prepared. Non-ambient X-ray diffraction measurement during annealing process and X-ray pole figures after annealing has been measured. Near epitaxial relationship was observed for bottom Pt layer grown on c-cut sapphire substrate: Pt(1 1 1)[11{sup ¯}0]||Al{sub 2}O{sub 3}(0 0 0 1)[11{sup ¯}00]. Inner titania layer shows randomly oriented both TiO{sub 2}-rutile (R) and anatase (A) phases with the volumetric ratio of R/A ∼ 2.7. If prepared without top Pt contact layer, the TiO{sub 2} transforms during annealing to random single anatase phase. The TiO{sub 2} layer overgrown with only single Pt top contact layer shows randomly oriented both rutile and anatase phases with volumetric ratio R/A ∼ 2.3. The top Pt layer on TiO{sub 2

  5. The influence of Pt redistribution on Ni1-xPtxSi growth properties

    Demeulemeester, J.; Smeets, D.; Temst, K.; Vantomme, A.; Comrie, C. M.; Van Bockstael, C.; Knaepen, W.; Detavernier, C.

    2010-01-01

    We have studied the influence of Pt on the growth of Ni silicide thin films by examining the Pt redistribution during silicide growth. Three different initial Pt configurations were investigated, i.e., a Pt alloy (Ni+Pt/ ), a Pt capping layer (Pt/Ni/ ) and a Pt interlayer (Ni/Pt/ ), all containing 7 at. % Pt relative to the Ni content. The Pt redistribution was probed using in situ real-time Rutherford backscattering spectrometry (RBS) whereas the phase sequence was monitored during the solid phase reaction (SPR) using in situ real-time x-ray diffraction. We found that the capping layer and alloy exhibit a SPR comparable to the pure Ni/ system, whereas Pt added as an interlayer has a much more drastic influence on the Ni silicide phase sequence. Nevertheless, for all initial sample configurations, Pt redistributes in an erratic way. This phenomenon can be assigned to the low solubility of Pt in Ni 2 Si compared to NiSi and the high mobility of Pt in Ni 2 Si compared to pure Ni. Real-time RBS further revealed that the crucial issue determining the growth properties of each silicide phase is the Pt concentration at the Si interface during the initial stages of phase formation. The formation of areas rich in Pt reduce the Ni silicide growth kinetics which influences the phase sequence and properties of the silicides.

  6. Shape resonances and EXAFS scattering in the $Pt L_{2,3}$ XANES from a Pt electrode

    O'Grady, W E

    1999-01-01

    Atomic hydrogen and oxygen adsorption on a platinum electrode in H /sub 2/SO/sub 4/ and HClO/sub 4/ electrolytes were studied by Pt L /sub 23/ XANES. The Pt electrode was formed of highly dispersed 1.5-3.0 nm particles supported on $9 carbon. A difference procedure utilizing the L/sub 2/ and L/sub 3/ spectra at various applied voltages was used to isolate the electronic and geometric effects in the XANES spectra. At 0.54 V (relative to RHE) the Pt electrode in $9 HClO/sub 4/ is assumed to be "clean". By taking the difference between the spectra at 0.0 and 0.54 V, the Pt-H antibonding state (electronic effect) is isolated and found to have a Fano-resonance line shape. In addition, a $9 significant Pt-H EXAFS scattering (geometric effect) was found for photon energies 0 to 20 eV above the edge. The difference between the spectra at 1.14 and 0.54 V allows isolation of the Pt-O antibonding state and the Pt-O EXAFS $9 scattering. (7 refs).

  7. Porcelain Product Quality Analysis in PT XYZ

    Ho Hwi Chie

    2015-12-01

    Full Text Available PT. XYZ is a company engaged in manufacturing porcelain dinner ware such as plates, cups, teapot, bowl, etc Porcelain product is safe for use and product defect will only affect the aesthetic not the functional side. The company always maintain the quality of the products produced as by maintaining a good product, in terms of visuals, will keep customers interested in the product. Good quality products characterized by quality A / B and C, and the product defect characterized by the quality of D, Lost, and BU. Concepts and methods used to analyze is a statistical process control (SPC which includes Pareto diagram, fraction nonconformities, flow charts and fishbone diagrams and management tools (fault tree analysis. Statistical Process Control (SPC is one of the methods, which includes Pareto charts, fraction nonconformities, flow chart, and fishbone diagram and also management tools (fault tree analysis. SPC is useful to find the facts from the problems and factors that affect the quality of the products, while fault tree analysis is useful to analyze each of the production process.

  8. Aplikasi Pemasaran Berbasis Web Pt Xyz

    Henny Hendarti

    2013-12-01

    Full Text Available Marketing plays an important role in determining the success of a company's sales. Marketing of goods or services over the Internet opens an opportunity for a company to expand the business into new markets, and compete with other businesses in the same field. It is because the internet offers wider selection of good products, service products, and prices. Thus, customers can be sure in choosing and buying of goods and services. For that e-marketing is introduced as an marketing strategy that integrates internet and marketing. A study was conducted to develop e-marketing application for PT XYZ as a company that produces and sells men’s apparel and accessories. The methodology used in developing the e-marketing application is library research, field research, and a seven-stage approach to build e-marketing. The e-marketing strategy developed is expected to expand market share and increase sales. Additionally, it is expected to be a powerful strategy to build relationships with customers, providing information of both company and its products.

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

    Nur Hidayati

    2016-03-01

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

  10. Actinide recovery from pyrochemical residues

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1984-01-01

    A new process for recovery of plutonium and americium from pyrochemical waste has been demonstrated. It is based on chloride solution anion exchange at low acidity, which eliminates corrosive HCl fumes. Developmental experiments of the process flowsheet concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 = from high chloride-low acid solution. Americium and other metals are washed from the ion exchange column with 1N HNO 3 -4.8M NaCl. The plutonium is recovered, after elution, via hydroxide precipitation, while the americium is recovered via NaHCO 3 precipitation. All filtrates from the process are discardable as low-level contaminated waste. Production-scale experiments are now in progress for MSE residues. Flow sheets for actinide recovery from electrorefining and direct oxide reduction residues are presented and discussed

  11. Actinide recovery from pyrochemical residues

    Avens, L.R.; Clifton, D.G.; Vigil, A.R.

    1985-05-01

    We demonstrated a new process for recovering plutonium and americium from pyrochemical waste. The method is based on chloride solution anion exchange at low acidity, or acidity that eliminates corrosive HCl fumes. Developmental experiments of the process flow chart concentrated on molten salt extraction (MSE) residues and gave >95% plutonium and >90% americium recovery. The recovered plutonium contained 6 2- from high-chloride low-acid solution. Americium and other metals are washed from the ion exchange column with lN HNO 3 -4.8M NaCl. After elution, plutonium is recovered by hydroxide precipitation, and americium is recovered by NaHCO 3 precipitation. All filtrates from the process can be discardable as low-level contaminated waste. Production-scale experiments are in progress for MSE residues. Flow charts for actinide recovery from electro-refining and direct oxide reduction residues are presented and discussed

  12. Coking of residue hydroprocessing catalysts

    Gray, M.R.; Zhao, Y.X. [Alberta Univ., Edmonton, AB (Canada). Dept. of Chemical Engineering; McKnight, C.A. [Syncrude Canada Ltd., Edmonton, AB (Canada); Komar, D.A.; Carruthers, J.D. [Cytec Industries Inc., Stamford, CT (United States)

    1997-11-01

    One of the major causes of deactivation of Ni/Mo and Co/Mo sulfide catalysts for hydroprocessing of heavy petroleum and bitumen fractions is coke deposition. The composition and amount of coke deposited on residue hydroprocessing catalysts depends on the composition of the liquid phase of the reactor. In the Athabasca bitumen, the high molecular weight components encourage coke deposition at temperatures of 430 to 440 degrees C and at pressures of 10 to 20 MPa hydrogen pressure. A study was conducted to determine which components in the heavy residual oil fraction were responsible for coking of catalysts. Seven samples of Athabasca vacuum residue were prepared by supercritical fluid extraction with pentane before being placed in the reactor. Carbon content and hydrodesulfurization activity was measured. It was concluded that the deposition of coke depended on the presence of asphaltenes and not on other compositional variables such as content of nitrogen, aromatic carbon or vanadium.

  13. Co-catalytic effect of nickel in Pt-Ru/C and Pt-Sn/C electrocatalysts for ethanol electrooxidation

    Ribadeneira, R. E.; Hoyos, B. A.

    2010-01-01

    In the present study, we examined the effect of adding nickel to Pt-Ru and Pt-Sn catalysts for ethanol electrooxidation. The alcohol-reduction process with ethylene glycol was used to prepare ten electrocatalysts. These were microchemically and physically characterized by EDX and XRD analysis. The electrocatalysts were evaluated at mini-electrodes with cyclic voltammetry at 25 and 50 °C in sulfuric acid and ethanol solutions, and as anodes in fuel cell tests. Nickel addition to Pt-Ru mixtures...

  14. Leaching From Biomass Gasification Residues

    Allegrini, Elisa; Boldrin, Alessio; Polletini, A.

    2011-01-01

    The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled with geoche......The aim of the present work is to attain an overall characterization of solid residues from biomass gasification. Besides the determination of chemical and physical properties, the work was focused on the study of leaching behaviour. Compliance and pH-dependence leaching tests coupled...

  15. Carbaryl residues in maize products

    Zayed, S.M.A.D.; Mansour, S.A.; Mostafa, I.Y.; Hassan, A.

    1976-01-01

    The 14 C-labelled insecticide carbaryl was synthesized from [1- 14 C]-1-naphthol at a specific activity of 3.18mCig -1 . Maize plants were treated with the labelled insecticide under simulated conditions of agricultural practice. Mature plants were harvested and studied for distribution of total residues in untreated grains as popularly roasted and consumed, and in the corn oil and corn germ products. Total residues found under these conditions in the respective products were 0.2, 0.1, 0.45 and 0.16ppm. (author)

  16. Combinatorial construction of toric residues

    Khetan, Amit; Soprounov, Ivan

    2004-01-01

    The toric residue is a map depending on n+1 semi-ample divisors on a complete toric variety of dimension n. It appears in a variety of contexts such as sparse polynomial systems, mirror symmetry, and GKZ hypergeometric functions. In this paper we investigate the problem of finding an explicit element whose toric residue is equal to one. Such an element is shown to exist if and only if the associated polytopes are essential. We reduce the problem to finding a collection of partitions of the la...

  17. Electrochemical oxidation of drug residues in water by the example of tetracycline, gentamicin and Aspirin {sup trademark}

    Weichgrebe, D.; Danilova, E.; Rosenwinkel, K.H. [Inst. of Water Quality and Waste Management, Univ. of Hannover, Hannover (Germany); Vedenjapin, A.; Baturova, M. [Inst. of Organic Chemistry, Russian Academy of Science, Moscow (Russian Federation)

    2003-07-01

    The electrochemical oxidation as a method to destroy drug residues like Aspirin {sup trademark}, tetracycline or gentamicin in water was investigated with C-Anode (modified by manganese oxides) and Pt Anode. The mechanism of Aspirin {sup trademark} and tetracycline oxidation and the influence of the biocide effect was observed using GC-MS and three different microbiological tests. In general the biological availability increases with progressive oxidation of the antibiotics. (orig.)

  18. Alternatives to crop residues for soil amendment

    Powell, J.M.; Unger, P.W.

    1997-01-01

    Metadata only record In semiarid agroecosystems, crop residues can provide important benefits of soil and water conservation, nutrient cycling, and improved subsequent crop yields. However, there are frequently multiple competing uses for residues, including animal forage, fuel, and construction material. This chapter discusses the various uses of crop residues and examines alternative soil amendments when crop residues cannot be left on the soil.

  19. Residual Structures in Latent Growth Curve Modeling

    Grimm, Kevin J.; Widaman, Keith F.

    2010-01-01

    Several alternatives are available for specifying the residual structure in latent growth curve modeling. Two specifications involve uncorrelated residuals and represent the most commonly used residual structures. The first, building on repeated measures analysis of variance and common specifications in multilevel models, forces residual variances…

  20. Computing Decoupled Residuals for Compact Disc Players

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  1. Electronic Properties of Graphene-PtSe2 Contacts.

    Sattar, Shahid; Schwingenschlögl, Udo

    2017-05-10

    In this article, we study the electronic properties of graphene in contact with monolayer and bilayer PtSe 2 using first-principles calculations. It turns out that there is no charge transfer between the components because of the weak van der Waals interaction. We calculate the work functions of monolayer and bilayer PtSe 2 and analyze the band bending at the contact with graphene. The formation of an n-type Schottky contact with monolayer PtSe 2 and a p-type Schottky contact with bilayer PtSe 2 is demonstrated. The Schottky barrier height is very low in the bilayer case and can be reduced to zero by 0.8% biaxial tensile strain.

  2. Electronic Properties of Graphene–PtSe2 Contacts

    Sattar, Shahid

    2017-04-26

    In this article, we study the electronic properties of graphene in contact with monolayer and bilayer PtSe2 using first-principles calculations. It turns out that there is no charge transfer between the components because of the weak van der Waals interaction. We calculate the work functions of monolayer and bilayer PtSe2 and analyze the band bending at the contact with graphene. The formation of an n-type Schottky contact with monolayer PtSe2 and a p-type Schottky contact with bilayer PtSe2 is demonstrated. The Schottky barrier height is very low in the bilayer case and can be reduced to zero by 0.8% biaxial tensile strain.

  3. Reactor Pressure Vessel P-T Limit Curve Round Robin

    Jang, C.H.; Moon, H.R.; Jeong, I.S. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    This report is the summary of the analysis results for the P-T Limit Curve construction which have been subjected to the round robin analysis. The purpose of the round robin is to compare the procedure and method used in various organizations to construct P-T limit curve to prevent brittle fracture of reactor pressure vessel of nuclear power plants. Each Participant used its own approach to construct the P-T limit curve and submitted the results, By analyzing the results, the reference procedure for the P-T limit curve could be established. This report include the results of the comparison of the procedure and method used by the participants, and sensitivity study of the key parameters. (author) 23 refs, 88 figs, 17 tabs.

  4. Roughening of Pt nanoparticles induced by surface-oxide formation

    Zhu, T.; Hensen, E.J.M.; Santen, van R.A.; Tian, N.; Sun, S.-G.; Kaghazchi, P.; Jacob, T.

    2013-01-01

    Using density functional theory (DFT) and thermodynamic considerations we studied the equilibrium shape of Pt nanoparticles (NPs) under electrochemical conditions. We found that at very high oxygen coverage, obtained at high electrode potentials, the experimentally-observed tetrahexahedral (THH) NPs

  5. Self-suspended permanent magnetic FePt ferrofluids

    Dallas, Panagiotis; Kelarakis, Antonios; Sahore, Ritu; DiSalvo, Francis J.; Livi, Sebastien; Giannelis, Emmanuel P.

    2013-01-01

    on the surface of L10 FePt nanoparticles. In contrast, all types of ferrofluids previously reported employ either volatile solvents as the suspending media or superparamagnetic iron oxide nanoparticles (that lacks permanent magnetization) as the inorganic

  6. Catalytically favorable surface patterns in Pt-Au nanoclusters

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2013-01-01

    Motivated by recent experimental demonstrations of novel PtAu nanoparticles with highly enhanced catalytic properties, we present a systematic theoretical study that explores principal catalytic indicators as a function of the particle size

  7. Electronic Properties of Graphene–PtSe2 Contacts

    Sattar, Shahid; Schwingenschlö gl, Udo

    2017-01-01

    In this article, we study the electronic properties of graphene in contact with monolayer and bilayer PtSe2 using first-principles calculations. It turns out that there is no charge transfer between the components because of the weak van der Waals interaction. We calculate the work functions of monolayer and bilayer PtSe2 and analyze the band bending at the contact with graphene. The formation of an n-type Schottky contact with monolayer PtSe2 and a p-type Schottky contact with bilayer PtSe2 is demonstrated. The Schottky barrier height is very low in the bilayer case and can be reduced to zero by 0.8% biaxial tensile strain.

  8. Fabrication of Pt/Au concentric spheres from triblock copolymer.

    Koh, Haeng-Deog; Park, Soojin; Russell, Thomas P

    2010-02-23

    Dispersion of an aqueous H(2)PtCl(6) solution into a trifluorotoluene (TFT) solution of a polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) (PS-b-P2VP-b-PEO) triblock copolymer produced an emulsion-induced hollow micelle (EIHM), comprising a water nanodroplet stabilized by PEO, H(2)PtCl(6)/P2VP, and PS, sequentially. The following addition of an aqueous LiAuCl(4) solution into the dispersion led to a coordination of LiAuCl(4) and PEO. The resulting spherical EIHM structure was transformed to a hollow cylindrical micelle by the fusion of spherical EIHM with the addition of methanol. This structural transition was reversible by the alternative addition of methanol and TFT. Oxygen plasma was used to generate Pt/Au concentric spheres and hollow cylindrical Pt/Au nano-objects.

  9. Glucose sensing based on Pt-MWCNT and MWCNT

    Aryasomayajula, Lavanya; Xie, Jining; Wang, Shouyan; Varadan, Vijay K.

    2007-04-01

    It is known that multi walled carbon nanotubes (MWCNTs) is an excellent materials for biosensing applications and with the introduction of Pt nanoparticles (Pt-MWCNTs) of about 3nm in diameter in MWCNTs greatly increases the current sensitivity and also the signal to noise ratio. We fabricated the CNT- based glucose sensor by immobilization the bio enzyme, glucose oxidase (GoX), on the Pt-MWCNT and electrode were prepared. The sensor has been tested effectively for both the abnormal blood glucose levels- greater than 6.9 mM and less than 3.5 mM which are the prediabetic and diabetic glucose levels, respectively. The current signal obtained from the Pt-MWCNT was much higher compared to the MWCNT based sensors.

  10. BChPT x 1/Nc: masses and currents

    Goity, Jose L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hampton Univ., Hampton, VA (United States); Fernando, Ishara P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hampton Univ., Hampton, VA (United States)

    2018-04-01

    A summary of the implementation of the combined BChPT X 1/Nc expansion for three flavors is presented, along with its applications to the octet and decuplet baryon masses, SU(3) charges and axial couplings.

  11. CLOUD COMPUTING ADOPTION STRATEGIES AT PT TASPEN INDONESIA, Tbk

    Julirzal Sarmedy

    2014-10-01

    Full Text Available PT. Taspen as Indonesian institution, is responsible for managing social insuranceprograms of civil servants. With branch offices and business partners who are geographicallydispersed throughout Indonesia, information technology is very important to support thebusiness processes. Cloud computing is a model of information technology services that couldpotentially increase the effectiveness and efficiency of PT. Taspen information system. Thisstudy examines the phenomenon exists at PT. Taspen in order to adopt cloud computing inthe information system, by using the framework of Technology-Organization-Environment,Diffusion of Innovation theory, and Partial Least Square method. Organizational factor isthe most dominant for PT. Taspen to adopt cloud computing. Referring to these findings,then a SWOT analysis and TOWS matrix are performed, which in this study recommendsthe implementation of a strategy model of cloud computing services that are private andgradually in process.

  12. Atom distribution and interactions in Ag{sub x}Pt{sub 1-x} and Au{sub x}Pt{sub 1-x} surface alloys on Pt(111)

    Roetter, Ralf T.; Bergbreiter, Andreas; Hoster, Harry E.; Behm, R. Juergen [Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm (Germany)

    2009-07-01

    The atom distributions in Ag{sub x}Pt{sub 1-x}/Pt(111) and Au{sub x}Pt{sub 1-x}/Pt(111) surface alloys were studied by high resolution UHV-STM. These surfaces were prepared by submonolayer Ag (Au) metal deposition on Pt(111), followed by annealing at 900 K or 1000 K, respectively, which in both cases results in surface confined 2D alloys, with equilibrated distribution of the components. Both systems show a tendency towards two-dimensional clustering, which fits well to their known bulk immiscibility. Effective cluster interactions (ECIs) will be derived by a quantitative evaluation of the 2D atom distributions in the surface alloys. By comparing the ECIs for PtAg and PtAu on Pt(111), and considering that Ag and Au have almost similar lattice constants, the results allow conclusion on the physical origin of the tendency for clustering.

  13. Porter Five Forces Model Pada PT. Ruci Gas

    Riky, Alfonsus

    2014-01-01

    Penelitian ini akan membahas mengenai analisis lima model utama kekuatan Porter pada Perusahaan keluarga PT.Ruci Gas. Tujuan dari penelitian ini penulis ingin menganalis tentang struktur industri PT. Ruci Gas yang dikaitkan dengan teori lima model kekuatan utama yang dikembangkan oleh Porter. Selain itu penulis ingin menganalisis mengenai tingkat atraktif investasi gas di Indonesia. Jenis dari penelitian ini adalah kualitatif deskriptif.Dengan pengumpulan data dengan metode wawancara dan obse...

  14. THE IMPACT OF ACQUISITION ON FINANCIAL PERFORMANCE OF PT. ABC

    Novian Zen; Noer Azam Achsani; Trias Andati

    2016-01-01

    This study aimed to analyze the financial performance of the subsidiary company (PT ABC) before and after acquired by the holding company (PT XYZ). The examined ratios of the financial performance were profitability and capital structure for the period of 2010-2014. This study utilized the t test tool. In the first and second year after the acquisition, the result shows that with the existence of business synergy, there was a change in financial performance although it was insignificant. Furt...

  15. An Analysis of Logistics Efficiency in PT. XYZ Surabaya Branch

    Leevana, Elyn

    2015-01-01

    Logistic efficiency is an important element in enhancement of company's competitiveness. Therefore, this research is conducted to investigate factors that influence logistics efficiency using the study case from PT. XYZ. PT. XYZ is a company in distribution industry that distributes palm oil products and other food products from the manufacturer to retail businesses. The researcher will analyze factors that influence logistics efficiency, measured by transportation costs in this research.Rese...

  16. Ordering process of sputtered FePt films

    Takahashi, Y.K.; Ohnuma, M.; Hono, K.

    2003-01-01

    We have investigated the in situ ordering process of sputtered FePt thin films deposited on heated substrates at 300 deg. C with different thicknesses. The films thinner than 50 nm were composed of nanograins (∼5 nm) of disordered FePt phase. Recrystallization occurred when films were grown thicker than 100 nm, and transformation twins were observed in recrystallized grains, in which ordering to the L1 0 structure was confirmed

  17. Pengaruh Customer Perceived Value Terhadap Customer Satisfaction PT. Xyz

    Sucahyo, Martinus Wilman

    2017-01-01

    Penelitian ini membahas tentang Customer Perceived Value terhadap Customer Satisfaction PT. XYZ. Dalam penelitian ini, Customer Perceived Value diukur melalui dimensi Core Product Value, Service Value dan Relationship Value. Masing-masing dimensi ini akan diuji pengaruhnya terhadap Customer Satisfaction, baik secara simultan maupun secara parsial, serta dimensi mana yang paling berpengaruh terhadap Customer Satisfaction. Sampel penelitian berjumlah 100 pelanggan PT. XYZ. Data penelitian diola...

  18. Strategy Formulation and Implementation for PT.Multigarmen Jaya

    Yoanita, Martha; Wandebori, Harimukti

    2013-01-01

    - The objective of this final project is to formulate and proposed the strategy for PT.Multigarmen Jaya (PT.MGJ) to faced the tight competition in garment industries. The analysis begins from environmental analysis that consist of external and internal analysis. For external analysis used PEST, Porter five forces, and competitor analysis, and for internal analysis used value chain analysis and resources analysis. From that analysis, there are several problems discovered, such as competitor ...

  19. Nalisis Kinerja Keuangan pada PT. Grand Victoria Hotel di Samarinda

    -, Atmajaya -

    2013-01-01

    Based on the results of analysis show that the performance of PT. Hotel Grand Victorian is measured using liquidity ratios and profitability ratios decreased from 2010-2012. Performance PT. Grand Victorian is measured using the liquidity ratio has decreased from year 2010-2012 consists of current ratio has decreased, and this is because the total current assets has increased and decreased. Meanwhile, the cash ratio from year 2010-2012 has increased, this is because the total cash and cash equ...

  20. Bulk ordering and surface segregation in Ni50Pt50

    Pourovskii, L.P.; Ruban, Andrei; Abrikosov, I.A.

    2001-01-01

    in the bulk compare well with experimental data. The surface-alloy compositions for the (111) and (110) facets above the ordering transition temperature are also found to be in a good agreement with experiments. It is demonstrated that the segregation profile at the (110) surface of NiPt is mainly caused...... by the unusually strong segregation of Pt into the second layer and the interlayer ordering due to large chemical nearest-neighbor interactions....

  1. Analisis Tingkat Likuiditas Pada PT. Telekomunikasi Indonesia Tbk

    KURANTA, SEFLIN SINTIA; MONTOLALU, JHONNY; TAMPI, DOLINA L

    2016-01-01

    The purpose of this study was to analyze the level of liquidity PT. Telekomunikasi Indonesia Tbk. If the company has good liquidity, the company was able to survive and complete with other companies. The method used in this research is descriptive quantitative method using liquidity ratio to Analyze the level of liquidity of the company. Based on the results of the analysis carried out showed that the level of liquidity PT. Telekomunikasi Indonesia Tbk has a Current Ratio pe...

  2. Nanocrystalline Fe-Pt alloys. Phase transformations, structure and magnetism

    Lyubina, J.V.

    2006-12-21

    This work has been devoted to the study of phase transformations involving chemical ordering and magnetic properties evolution in bulk Fe-Pt alloys composed of nanometersized grains. Nanocrystalline Fe{sub 100-x}Pt{sub x} (x=40-60) alloys have been prepared by mechanical ball milling of elemental Fe and Pt powders at liquid nitrogen temperature. The as-milled Fe-Pt alloys consist of {proportional_to} 100 {mu}m sized particles constituted by randomly oriented grains having an average size in the range of 10-40 nm. Depending on the milling time, three major microstructure types have been obtained: samples with a multilayer-type structure of Fe and Pt with a thickness of 20-300 nm and a very thin (several nanometers) A1 layer at their interfaces (2 h milled), an intermediate structure, consisting of finer lamellae of Fe and Pt (below approximately 100 nm) with the A1 layer thickness reaching several tens of nanometers (4 h milled) and alloys containing a homogeneous A1 phase (7 h milled). Subsequent heat treatment at elevated temperatures is required for the formation of the L1{sub 0} FePt phase. The ordering develops via so-called combined solid state reactions. It is accompanied by grain growth and thermally assisted removal of defects introduced by milling and proceeds rapidly at moderate temperatures by nucleation and growth of the ordered phases with a high degree of the long-range order. In a two-particle interaction model elaborated in the present work, the existence of hysteresis in recoil loops has been shown to arise from insufficient coupling between the low- and the high-anisotropy particles. The model reveals the main features of magnetisation reversal processes observed experimentally in exchange-coupled systems. Neutron diffraction has been used for the investigation of the magnetic structure of ordered and partially ordered nanocrystalline Fe-Pt alloys. (orig.)

  3. PZ, PT and PZT formation from metal citrates

    Bastos, C.M.R.; Zaghette, M.A.; Jafelicci Junior, M.; Varela, J.A.

    1990-01-01

    Lead zirconate, lead titanate and lead titanate-zirconate were obtained by mechanical mixing of lead, titanium and zirconium citrates in ether and by calcination. The process was analyzed by DTA, TGA, IR, pore size distribution and surface area measurements. The results indicate that the decomposition reaction and formation of PZ, PT occur simultaneaously without formation of intermediate compounds. PZT was formed from 500 0 C. (author) [pt

  4. Kesejahteraan Karyawan PT. Royal Coconut Kabupaten Minahasa Utara

    Londa, Very Y; Kaunang, Markus; Karim, Dian Fitriani

    2015-01-01

    Employee welfare is a form of welfare services provided by the company to the employees who have given power, mind and their services. Company Parties have an obligation to make efforts to motivate employees to provide benefits that can improve employee productivity. Welfare programs provided by the company to employees of PT. Royal Coconut North Minahasa yet either. Using qualitative methodology, research results show that the well-being of employees is not a good idea due to the PT. Royal C...

  5. Integrated Marketing Communications (IMC) di PT Halo Rumah Bernyanyi

    Rebekka Rismayanti

    2017-01-01

    Abstract: This research aims to describe the effectiveness of Integrated Marketing Communication (IMC) in PT Halo Rumah Bernyanyi which, from the perspective of marketing strategy, could be studied by analyzing the segmentation, targeting, and positioning. Using case-study method with in-depth interview, the result shows that the implementation of IMC at PT Halo Rumah Bernyayi is arranged in one single strategy and tend to neglect the complexities of running multi-brand family karaoke-house. ...

  6. Integrated Marketing Communications (IMC) Di PT Halo Rumah Bernyanyi

    Rismayanti, Rebekka

    2016-01-01

    : This research aims to describe the effectiveness of Integrated Marketing Communication (IMC) in PT Halo Rumah Bernyanyi which, from the perspective of marketing strategy, could be studied by analyzing the segmentation, targeting, and positioning. Using case-study method with in-depth interview, the result shows that the implementation of IMC at PT Halo Rumah Bernyayi is arranged in one single strategy and tend to neglect the complexities of running multi-brand family karaoke-house. This con...

  7. KOMUNIKASI PEMASARAN PT PINDAD (PERSERO DI KAWASAN ASIA TENGGARA

    Mochamad Yoesdinar Oktora

    2017-12-01

    Full Text Available Pemasaran yang dilakukan PT Pindad berkenaan dengan konsep konsep G to G dan menjadikan kepentingan publik serta isu keamanan negara sebagai nilai jualnya.. Oleh karena itu, penelitian ini bertujuan untuk dapat mendeskripsikan dan menganalisa Integrated Marketing Communication (IMC PT Pindad (Persero dalam memasarkan Alutsista di Kawasan Asia Tenggara. Penelitian ini berdasarkan paradigma postpositivisme, serta pendekatan kualitatif dengan metode studi kasus. Informan sebanyak 4 orang yang dipilih secara purposif. Teknik pengumpulan data melalui wawancara, observasi non partisipan dan studi literatur. Teknik analisis data melalui model interaktif dan Miles & Huberman, sedangkan teknik validasi data melalui triangulasi sumber. Hasil penelitian menunjukan bahwa IMC PT Pindad dilakukan melalui Acara dan pengalaman, Promosi penjualan, Hubungan masyarakat dan publisitas, Pemasaran langsung, Penjualan, dan Periklanan. Alasan PT Pindad menggunakan IMC utamanya karena penerapan konsep G to G yang mengedepankan lobi-lobi di tingkat pemerintah serta hubungan bilateral dapat mendukung seluruh kegiatan pemasarannya. Evaluasi IMC PT Pindad menghasilkan output berupa kegiatan pemasaran yang berkontribusi positif pada penjulan yakni kegiatan penjualan personal melalui lobi-lobi di kalangan pemerintah serta penempatan agen-agen representatif PT Pindad di berbagai negara perwakilan Asia Tenggara. Sedangkan kegiatan pemasaran yang kurang berkontribusi pada penjualan Alutsista yakni periklanan.

  8. The nucleation and growth of intermetallic Al-Pt phases

    Kovacs, A.; Barna, P.B.; Labar, J. l.

    2002-01-01

    The nucleation and growth of intermetallic Al-Pt phases on amorphous carbon was investigated by half shadow technique in co-deposited thin films. In such experimental condition, the composition of the deposited films varied in the range of Al x Pt 1-x (0≤x≤0.6). The coexistence of Al 5 Pt, Al 2 Pt, Al 3 Pt 2 intermetallic phases have been found in the whole range with varying ratio. Vapour depositions were performed in an UHV system. The Al and Pt components were evaporated simultaneously onto amorphous carbon layer supported by TEM micro-grids. Deposition rates were controlled separately by quartz crystal monitors. Substrate temperature during deposition was 350 grad C. A special evaporation arrangement made possible to create a half shadow area on the substrate in which the quantity one of the components increased from zero to the wanted composition of the sample. The composition of the zones was determined by energy dispersive X-ray spectroscopy (EDS) in TEM. The intermetallic phases developed in the sample were investigated by analytical TEM (Philips CM20) and high resolution TEM (JEOL 3010 UHR). The electron diffraction patterns have been evaluated by ProcessDiffraction program. (Authors)

  9. Exotic high activity surface patterns in PtAu nanoclusters

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  10. Pengelolaan Media Sosial Oleh Unit Corporate Communication PT GMF Aeroasia

    Fajar Syuderajat

    2017-10-01

    Full Text Available Studi ini berjudul:  Pengelolaan  Media  Sosial  oleh  Unit Corporate Communication PT GMF AeroAsia. Seiring dengan meningkatknya jumlah pengguna social media telah melahirkan media baru bagi bidang komunikasi khususnya dunia public relations. Kesempatan ini kemudian dimanfaatkan oleh PT GMF AeroAsia untuk memanfaatkan media sosial yang dijadikan sebagai media komunikasi dengan memberikan  informasi  seputar  dunia  aviasi  dan  bidang  MRO  (maintenance, repair,  organization  PT  GMF AeroAsia.   Tujuan studi ini, untuk mengetahui pengelolaan media sosial yang digunakan PT GMF AeroAsia sebagai strategi komunikasi brand awareness dengan konsep  teori yang digunakan dalam penelitian ini adalah New Media Theory yang berhubungan dengan media sosial. Metode pendekatan penulisan kualitatif dan bersifat deskriptif. Hasil dari studi ini mengatakan bahwa pengelolaan media sosial PT GMF AeroAsia oleh Corporate Communication memilih facebook, instagram, youtube, dan linkedin. Penanganan langsung dilakukan oleh tim digital aktivasi dengan konten-konten yang terlebih dahulu disetujui oleh kepala divisi Corporate Communication.   Kesimpulan, PT GMF AeroAsia menggunakan facebook, instagram, youtube, dan linkedin sesuai dengan segmentasi perusahaan yang lebih menekankan B-to-B. Meskipun banyak sekali follower pada media sosial tersebut namun untuk respon atau feedback kurang mendapatkan perhatian, sehingga terkesan lambat dalam menanggapi. Kata kunci: corporate communication;  media sosial; PT GMF AeroAsia.

  11. Electrochemistry of Phosphorous and Hypophosphorous Acid on a Pt electrode

    Prokop, M.; Bystron, T.; Bouzek, K.

    2015-01-01

    Highlights: • H 3 PO 3 and H 3 PO 2 oxidation on Pt electrode proceed at high overpotential. • H 3 PO 2 oxidation proceeds via H 3 PO 3 as intermediate. • H 3 PO 3 and H 3 PO 2 adsorb on Pt electrode, adsorption isotherms determined. • Adsorption is more pronounced at elevated temperature. • Tautomeric equilibria plays an important role in the acids behaviour. - Abstract: H 3 PO 4 is commonly used as a proton-conducting phase in high temperature proton exchange membrane fuel cell membranes. However, its reduction with hydrogen at elevated temperatures yields compounds like H 3 PO 3 and phosphorus. The aim of this work was to describe the basic electrochemical behaviour of H 3 PO 3 and H 3 PO 2 on a Pt electrode in diluted aqueous H 2 SO 4 solutions. The results show that adsorption of both phosphorus acids studied becomes important at an oxoacid bulk concentration around and below 10 mol dm −3 . Adsorption isotherms at 25 and 70 °C were determined for both acids. Unusually, the extent of adsorption increases with rising temperature. H 3 PO 3 is anodically oxidised on a bare Pt as well as on a PtO surface. H 3 PO 2 oxidation proceeds mainly on a PtO surface, with the intermediate product being H 3 PO 3 . High overvoltage around 1 V is characteristic of all anodic oxidation reactions occurring in the temperature range studied

  12. Reversible structural modulation of Fe-Pt bimetallic surfaces and its effect on reactivity.

    Ma, Teng; Fu, Qiang; Su, Hai-Yan; Liu, Hong-Yang; Cui, Yi; Wang, Zhen; Mu, Ren-Tao; Li, Wei-Xue; Bao, Xin-He

    2009-05-11

    Tunable surface: The surface structure of the Fe-Pt bimetallic catalyst can be reversibly modulated between the iron-oxide-rich Pt surface and the Pt-skin structure with subsurface Fe via alternating reduction and oxidation treatments (see figure). The regenerated active Pt-skin structure is active in reactions involving CO and/or O.

  13. Atomic layer deposition synthesis and evaluation of core–shell Pt-WC electrocatalysts

    Hsu, Irene J.; Chen, Jingguang G.; Jiang, Xiaoqiang; Willis, Brian G.

    2015-01-01

    Pt-WC core shell particles were produced using atomic layer deposition (ALD) to deposit Pt layers onto WC particle substrates. A range of Pt depositions were used to determine the growth mechanism for the Pt-WC powder system. TEM imaging and Cu stripping voltammetry found that Pt ALD growth on WC powder substrates was similar to that on WC thin films. However, excess free carbon was found to affect Pt ALD by blocking adsorption sites on WC. The Pt-WC samples were evaluated for the oxygen reduction reaction using a rotating disk electrode to obtain quantitative activity information. The mass and specific activities for the 30 and 50 ALD cycle samples were found to be comparable to a 10 wt. % Pt/C catalyst. However, higher overpotentials and lower limiting currents were observed with ALD Pt-WC compared to Pt/C catalysts, indicating that the oxygen reduction mechanism is not as efficient on Pt-WC as on bulk Pt. Additionally, these Pt-WC catalysts were used to demonstrate hydrogen evolution reaction activity and were found to perform as well as bulk Pt catalyst but with a fraction of the Pt loading, in agreement with the previous work on Pt-WC thin film catalysts

  14. Nanocomposite for methanol oxidation: synthesis and characterization of cubic Pt nanoparticles on graphene sheets

    Tung-Yuan Yung, Jer-Yeu Lee and Ling-Kang Liu

    2013-01-01

    Full Text Available We present our recent results on Pt nanoparticles on graphene sheets (Pt-NPs/G, a nanocomposite prepared with microwave assistance in ionic liquid 2-hydroxyethanaminiumformate. Preparation of Pt-NPs/G was achieved without the addition of extra reductant such as hydrazine or ethylene glycol. The Pt nanoparticles on graphene have a cubic-like shape (about 60 wt% Pt loading, Pt-NPs/G and the particle size is 6 ± 3 nm from transmission electron microscopy results. Electrochemical cyclic voltammetry studies in 0.5 M aqueous H2SO4 were performed using Pt-NPs/G and separately, for comparison, using a commercially available electrocatalyst (60 wt% Pt loading, Pt/C. The electrochemical surface ratio of Pt-NPs/G to Pt/C is 0.745. The results of a methanol oxidation reaction (MOR in 0.5 M aqueous H2SO4 + 1.0 M methanol for the two samples are presented. The MOR results show that the ratios of the current density of oxidation (If to the current density of reduction (Ib are 3.49 (Pt-NPs/G and 1.37 (Pt/C, respectively, with a preference by 2.55 times favoring Pt-NPs/G. That is, the tolerance CO poisoning of Pt-NPs/G is better than that of commercial Pt/C.

  15. Analytical tools and methodologies for evaluation of residual life of contacting pressure tubes in the early generation of Indian PHWRs

    Sinha, S.K.; Madhusoodanan, K.; Rupani, B.B.; Sinha, R.K.

    2002-01-01

    In-service life of a contacting Zircaloy-2 pressure tube (PT) in the earlier generation of Indian PHWRs, is limited mainly due to the accelerated hydrogen pick-up and nucleation and growth of hydride blister(s) at the cold spot(s) formed on outside surface of pressure tube as a result of its contact with the calandria tube (CT). The activities involving development of the analytical models for simulating the degradation mechanisms leading to PT-CT contact and the methodologies for the revaluation of their safe life under such condition form the important part of our extensive programme for the life management of contacting pressure tubes. Since after the PT-CT contact, rate of hydrogen pick-up and nucleation and growth of hydride blisters govern the safe residual life of the pressure tube, two analytical models (a) hydrogen pick-up model ('HYCON') and (b) model for the nucleation and growth of hydride blister at the contact spot ('BLIST -2D') have been developed in-house to estimate the extent of degradation caused by them. Along with them, a methodology for evaluation of safe residual life has also been formulated for evaluating the safe residual life of the contacting channels. This paper gives the brief description of the models and the methodologies relevant for the contacting Zircaloy-2 pressure tubes. (author)

  16. Magnetic reversal processes and critical thickness in FePt/α-Fe/FePt trilayers

    Guo, N.L.; Zhao, G.P.; Zhang, H.W.; Zhou, X.L.; Deng, Y.

    2011-01-01

    Magnetic reversal processes of a FePt/α-Fe/FePt trilayer system with in-plane easy axes have been investigated within a micromagnetic approach. It is found that the magnetic reversal process consists of three steps: nucleation of a prototype of domain wall in the soft phase, the evolution as well as the motion of the domain wall from the soft to the hard phase and finally, the magnetic reversal of the hard phase. For small soft layer thickness L s , the three steps are reduced to one single step, where the magnetizations in the two phases reverses simultaneously and the hysteresis loops are square with nucleation as the coercivity mechanism. As L s increases, both nucleation and pinning fields decrease. In the meantime, the single-step reversal expands to a standard three-step one and the coercivity mechanism changes from nucleation to pinning. The critical thickness where the coercivity mechanism alters, could be derived analytically, which is found to be inversely proportional to the square root of the crystalline anisotropy of the hard phase. Such a scaling law might provide an easy way to test the present theory. Further increase of L s leads to the change of the coercivity mechanism from pinning to nucleation. - Highlights: → Analytical critical thickness scales with square root of anisotropy of hard phase. → Reversal process determined nucleation, motion and depinning of domain walls. → Coercivity mechanism is nucleation and pinning for thin and thick soft layers. → Microscopic and macroscopic hysteresis loops calculated.

  17. Managing woodwaste: Yield from residue

    Nielson, E. [LNS Services, Inc., North Vancouver, British Columbia (Canada); Rayner, S. [Pacific Waste Energy Inc., Burnaby, British Columbia (Canada)

    1993-12-31

    Historically, the majority of sawmill waste has been burned or buried for the sole purpose of disposal. In most jurisdictions, environmental legislation will prohibit, or render uneconomic, these practices. Many reports have been prepared to describe the forest industry`s residue and its environmental effect; although these help those looking for industry-wide or regional solutions, such as electricity generation, they have limited value for the mill manager, who has the on-hands responsibility for generation and disposal of the waste. If the mill manager can evaluate waste streams and break them down into their usable components, he can find niche market solutions for portions of the plant residue and redirect waste to poor/no-return, rather than disposal-cost, end uses. In the modern mill, residue is collected at the individual machine centre by waste conveyors that combine and mix sawdust, shavings, bark, etc. and send the result to the hog-fuel pile. The mill waste system should be analyzed to determine the measures that can improve the quality of residues and determine the volumes of any particular category before the mixing, mentioned above, occurs. After this analysis, the mill may find a niche market for a portion of its woodwaste.

  18. Residual stress in polyethylene pipes

    Poduška, Jan; Hutař, Pavel; Kučera, J.; Frank, A.; Sadílek, J.; Pinter, G.; Náhlík, Luboš

    2016-01-01

    Roč. 54, SEP (2016), s. 288-295 ISSN 0142-9418 R&D Projects: GA MŠk LM2015069; GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : polyethylene pipe * residual stress * ring slitting method * lifetime estimation Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.464, year: 2016

  19. Solow Residuals Without Capital Stocks

    Burda, Michael C.; Severgnini, Battista

    2014-01-01

    We use synthetic data generated by a prototypical stochastic growth model to assess the accuracy of the Solow residual (Solow, 1957) as a measure of total factor productivity (TFP) growth when the capital stock in use is measured with error. We propose two alternative measurements based on curren...

  20. Solidification process for sludge residue

    Pearce, K.L.

    1998-01-01

    This report investigates the solidification process used at 100-N Basin to solidify the N Basin sediment and assesses the N Basin process for application to the K Basin sludge residue material. This report also includes a discussion of a solidification process for stabilizing filters. The solidified matrix must be compatible with the Environmental Remediation Disposal Facility acceptance criteria

  1. Leptogenesis and residual CP symmetry

    Chen, Peng; Ding, Gui-Jun; King, Stephen F.

    2016-01-01

    We discuss flavour dependent leptogenesis in the framework of lepton flavour models based on discrete flavour and CP symmetries applied to the type-I seesaw model. Working in the flavour basis, we analyse the case of two general residual CP symmetries in the neutrino sector, which corresponds to all possible semi-direct models based on a preserved Z 2 in the neutrino sector, together with a CP symmetry, which constrains the PMNS matrix up to a single free parameter which may be fixed by the reactor angle. We systematically study and classify this case for all possible residual CP symmetries, and show that the R-matrix is tightly constrained up to a single free parameter, with only certain forms being consistent with successful leptogenesis, leading to possible connections between leptogenesis and PMNS parameters. The formalism is completely general in the sense that the two residual CP symmetries could result from any high energy discrete flavour theory which respects any CP symmetry. As a simple example, we apply the formalism to a high energy S 4 flavour symmetry with a generalized CP symmetry, broken to two residual CP symmetries in the neutrino sector, recovering familiar results for PMNS predictions, together with new results for flavour dependent leptogenesis.

  2. Preparation of Pt Au/C and Pt Au Bi/C electrocatalysts using electron beam irradiation for ethanol electro-oxidation in alkaline medium

    Silva, Dionisio F.; Geraldes, Adriana N.; Cardoso, Elisangela S.Z.; Gomes, Thiago B.; Linardi, Marcelo; Oliveira Neto, Almir; Spinace, Estevam V.

    2011-01-01

    Pt Au/C (50:50) and PtAuBi/C electrocatalysts with Pt:Au:Bi atomic ratios of 50:40:10, 50:30:20 and 50:10:40 were prepared in water/2-propanol using electron beam irradiation. The materials were characterized by X-ray diffraction (XRD) and the electro-oxidation of ethanol was studied by chronoamperometry at room temperature. The X-ray diffraction measurements for all electrocatalysts prepared showed four peaks, which are associated with the planes of the face-centered cubic (fcc) structure characteristic of Pt and Pt alloys. For PtAuBi/C it was also observed the presence of a mixture of BiPt alloys and bismuth phases. The average crystallite sizes for Pt/C, PtAu/C, PtAuBi/C (50:40:10), PtAuBi/C (50:30:20) and PtAuBi/C (50:10:40) were in the range of 2.0 - 4.0 nm. The activity of the electrocatalysts for ethanol oxidation in alkaline medium showed that PtAuBi/C (50:40:10) had a higher performance for ethanol oxidation compared to others electrocatalysts prepared. (author)

  3. Comparison of different promotion effect of PtRu/C and PtSn/C electrocatalysts for ethanol electro-oxidation

    Li, Huanqiao; Cao, Lei [Direct Alcohol Fuel Cell Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of the Chinese Academy Sciences, Beijing 100039 (China); Sun, Gongquan; Jiang, Luhua [Direct Alcohol Fuel Cell Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Xin, Qin [Direct Alcohol Fuel Cell Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2007-08-01

    Well dispersed PtSn/C, PtRu/C and Pt/C electrocatalysts were synthesized by a modified polyol process and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and inductively coupled plasma-atomic emission spectrometry techniques. XRD patterns show that Ru induces the contraction of Pt lattice parameter while Sn makes the Pt crystal lattice extended. Ethanol oxidation activities on the catalysts were studied via cyclic voltammetry (CV) and chronoamperometry (CA) methods at room temperature. It is found that the electrode potential plays an important role in the electrochemical behavior of ethanol oxidation on PtRu/C and PtSn/C catalysts. In the lower potential region, PtSn/C possesses higher performance for ethanol oxidation, while in the higher potential region PtRu/C is more active. The different promotion effects of PtSn/C and PtRu/C to ethanol oxidation can be explained by the structural effect and modified bi-functional mechanism in different potential region. Single cell test of a direct ethanol fuel cell (DEFC) was also carried out to elucidate the promotion effect of PtRu/C and PtSn/C catalysts on the ethanol oxidation at 90 C. (author)

  4. Use of Hydrogen Chemisorption and Ethylene Hydrogenation as Predictors for Aqueous Phase Reforming of Lactose over Ni@Pt and Co@Pt Bimetallic Overlayer Catalysts

    Lai, Qinghua; Skoglund, Michael D.; Zhang, Chen; Morris, Allen R.; Holles, Joseph H.

    2016-10-20

    Overlayer Pt on Ni (Ni@Pt) or Co (Co@Pt) were synthesized and tested for H2 generation from APR of lactose. H2 chemisorption descriptor showed that Ni@Pt and Co@Pt overlayer catalysts had reduced H2 adsorption strength compared to a Pt only catalyst, which agree with computational predictions. The overlayer catalysts also demonstrated lower activity for ethylene hydrogenation than the Pt only catalyst, which likely resulted from decreased H2 binding strength decreasing the surface coverage of H2. XAS results showed that overlayer catalysts exhibited higher white line intensity than the Pt catalyst, which indicates a negative d-band shift for the Pt overlayer, further providing evidence for overlayer formation. Lactose APR studies showed that lactose can be used as feedstock to produce H2 and CO under desirable reaction conditions. The Pt active sites of Ni@Pt and Co@Pt overlayer catalysts showed significantly enhanced H2 production selectivity and activity when compared with that of a Pt only catalyst. The single deposition overlayer with the largest d-band shift showed the highest H2 activity. The results suggest that overlayer formation using directed deposition technique could modify the behavior of the surface metal and ultimately modify the APR activity.

  5. Comparison of different promotion effect of PtRu/C and PtSn/C electrocatalysts for ethanol electro-oxidation

    Li, Huanqiao; Sun, Gongquan; Cao, Lei; Jiang, Luhua; Xin, Qin

    2007-01-01

    Well dispersed PtSn/C, PtRu/C and Pt/C electrocatalysts were synthesized by a modified polyol process and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and inductively coupled plasma-atomic emission spectrometry techniques. XRD patterns show that Ru induces the contraction of Pt lattice parameter while Sn makes the Pt crystal lattice extended. Ethanol oxidation activities on the catalysts were studied via cyclic voltammetry (CV) and chronoamperometry (CA) methods at room temperature. It is found that the electrode potential plays an important role in the electrochemical behavior of ethanol oxidation on PtRu/C and PtSn/C catalysts. In the lower potential region, PtSn/C possesses higher performance for ethanol oxidation, while in the higher potential region PtRu/C is more active. The different promotion effects of PtSn/C and PtRu/C to ethanol oxidation can be explained by the structural effect and modified bi-functional mechanism in different potential region. Single cell test of a direct ethanol fuel cell (DEFC) was also carried out to elucidate the promotion effect of PtRu/C and PtSn/C catalysts on the ethanol oxidation at 90 o C

  6. Preparation of Pt Au/C and Pt Au Bi/C electrocatalysts using electron beam irradiation for ethanol electro-oxidation in alkaline medium

    Silva, Dionisio F.; Geraldes, Adriana N.; Cardoso, Elisangela S.Z.; Gomes, Thiago B.; Linardi, Marcelo; Oliveira Neto, Almir; Spinace, Estevam V., E-mail: dfsilva@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Pt Au/C (50:50) and PtAuBi/C electrocatalysts with Pt:Au:Bi atomic ratios of 50:40:10, 50:30:20 and 50:10:40 were prepared in water/2-propanol using electron beam irradiation. The materials were characterized by X-ray diffraction (XRD) and the electro-oxidation of ethanol was studied by chronoamperometry at room temperature. The X-ray diffraction measurements for all electrocatalysts prepared showed four peaks, which are associated with the planes of the face-centered cubic (fcc) structure characteristic of Pt and Pt alloys. For PtAuBi/C it was also observed the presence of a mixture of BiPt alloys and bismuth phases. The average crystallite sizes for Pt/C, PtAu/C, PtAuBi/C (50:40:10), PtAuBi/C (50:30:20) and PtAuBi/C (50:10:40) were in the range of 2.0 - 4.0 nm. The activity of the electrocatalysts for ethanol oxidation in alkaline medium showed that PtAuBi/C (50:40:10) had a higher performance for ethanol oxidation compared to others electrocatalysts prepared. (author)

  7. Stabilization of Pt nanoparticles by single stranded DNA and the binary assembly of Au and Pt nanoparticles without hybridization

    Yang, J.; Lee, Jim Yang; Too, Heng-Phon; Chow, Gan-Moog; Gan, Leong M.

    2006-01-01

    The non-specific interaction between single stranded DNA (ssDNA) and 12 nm Pt nanoparticles is investigated in this work. The data show a strong and non-specific interaction between the two which can be exploited for the stabilization of Pt nanoparticles in aqueous solutions. Based on the experimental findings, a non-hybridization based protocol to assemble 17 nm Au and Pt nanoparticles (12 nm cubic and 3.6 nm spherical) by single-stranded DNA was developed. Transmission electron microscopy (TEM) and UV-visible spectroscopy confirmed that Au and Pt nanoparticles could be assembled by the non-specific interaction in an orderly manner. The experimental results also caution against the potential pitfalls in using DNA melting point analysis to infer metal nanoparticle assembly by DNA hybridization

  8. Evaluation of Pt-Ru-Ni and Pt-Sn-Ni catalysts as anodes in direct ethanol fuel cells

    Ribadeneira, Esteban; Hoyos, Bibian A. [Escuela de Procesos y Energia, Facultad de Minas, Universidad Nacional de Colombia, Medellin (Colombia)

    2008-05-15

    In this study, the electrooxidation of ethanol on carbon supported Pt-Ru-Ni and Pt-Sn-Ni catalysts is electrochemically studied through cyclic voltammetry at 50 C in direct ethanol fuel cells. All electrocatalysts are prepared using the ethylene glycol-reduction process and are chemically characterized by energy-dispersive X-ray analysis (EDX). For fuel cell evaluation, electrodes are prepared by the transfer-decal method. Nickel addition to the anode improves DEFC performance. When Pt{sub 75}Ru{sub 15}Ni{sub 10}/C is used as an anode catalyst, the current density obtained in the fuel cell is greater than that of all other investigated catalysts. Tri-metallic catalytic mixtures have a higher performance relative to bi-metallic catalysts. These results are in agreement with CV results that display greater activity for PtRuNi at higher potentials. (author)

  9. New tests to detect antiphospholipid antibodies: antiprothrombin (aPT) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies.

    Sciascia, Savino; Khamashta, Munther A; Bertolaccini, Maria Laura

    2014-05-01

    Antiprothrombin antibodies have been proposed as potential new biomarkers for thrombosis and/or pregnancy morbidity in the setting of the antiphospholipid syndrome (APS). Antiprothrombin antibodies are commonly detected by ELISA, using prothrombin coated onto irradiated plates (aPT), or prothrombin in complex with phosphatidylserine (aPS/PT), as antigen. Although these antibodies can co-exist in the same patient, aPT and aPS/PT seem to belong to different populations of autoantibodies. Early research explored the role of antibodies to prothrombin as potential antigenic targets for the lupus anticoagulant (LA). To date their clinical significance is being investigated and their potential role in identifying patients at higher risk of developing thrombotic events or pregnancy morbidity is being probed.

  10. The electrocatalytic properties of carbon supported PtRu/C nanoalloys in oxidation of small organic molecules: Comparison with Pt/C catalyst

    Lović Jelena D.

    2012-01-01

    Full Text Available The electrocatalytic activity of carbon supported PtRu/C catalysts, with different composition, toward the electrooxidation of methanol, CO and formic acid were examined in acid and alkaline solution at ambient temperature using thin-film rotating disk electrode (RDE method and compared with activity of Pt/C. The catalysts were characterized by XRD, AFM and STM techniques. XRD pattern revealed that PtRu-1/C catalyst is consisted of two structures e.g. Pt-Ru-fcc and Ru-hcp (the solid solution of Ru in Pt and the small amount of Ru or solid solution of Pt in Ru, as opposed to PtRu-2/C catalyst which is consisted of one structure mostly, Pt-Ru-fcc. According to STM images, PtRu as well as Pt, particles size were between 2 and 6 nm, which is in a good agreement with the mean particles size determined by XRD. To establish the activity and stability of the catalysts potentiodynamic and quasi steady-state measurements were performed. It was found that the activity of Pt and PtRu for CO and methanol oxidation is a strong function of pH of solution. The kinetics are much higher in alkaline than in acid solution and the difference between Pt/C and PtRu/C is much less pronounced in alkaline media. Results presented in this work indicate that activity of PtRu catalysts depends on catalyst composition, e.g. on Pt/Ru atomic ratio, as well as on alloying degree of catalysts. Comparison of CO, methanol and formic acid oxidation on PtRu-2/C, PtRu-1/C and Pt/C catalysts revealed that PtRu-2/C is the most active one. It was shown that the PtRu-2/C catalyst, due to fact that it is consisted of only one phase, with high alloying degree, through the bifunctional mechanism improved by electronic effect, achieve the activity two times higher related to PtRu-1/C in the oxidation of all organic molecules investigated, and about three times higher compared to Pt/C in the oxidation of methanol and CO, and five times higher in formic acid oxidation.

  11. Optimum Pt and Ru atomic composition of carbon-supported Pt-Ru alloy electrocatalyst for methanol oxidation studied by the polygonal barrel-sputtering method

    Hiromi, Chikako; Inoue, Mitsuhiro; Taguchi, Akira; Abe, Takayuki

    2011-01-01

    Highlights: → The sputtered Pt and Ru form the Pt-Ru alloy nanoparticles on the carbon support. → The deposited Pt-Ru alloy particles have uniform Pt:Ru atomic ratios. → The optimum Pt:Ru ratio of the Pt-Ru/C for methanol oxidation is 58:42 at.% at 25 deg. C. → The optimum Pt:Ru ratio of 58:42 shifts to 50:50 at.% at 40 and 60 deg. C. → The polygonal barrel-sputtering method is useful to prepare the DMFC anode catalyst. - Abstract: The optimum Pt and Ru atomic composition of a carbon-supported Pt-Ru alloy (Pt-Ru/C) used in a practical direct methanol fuel cell (DMFC) anode was investigated. The samples were prepared by the polygonal barrel-sputtering method. Based on the physical properties of the prepared Pt-Ru/C samples, the Pt-Ru alloy was found to be deposited on a carbon support. The microscopic characterization showed that the deposited alloy forms nanoparticles, of which the atomic ratios of Pt and Ru (Pt:Ru ratios) are uniform and are in accordance with the overall Pt:Ru ratios of the samples. The formation of the Pt-Ru alloy is also supported by the electrochemical characterization. Based on these results, methanol oxidation on the Pt-Ru/C samples was measured by cyclic voltammetry and chronoamperometry. The results indicated that the methanol oxidation activities of the prepared samples depended on the Pt:Ru ratios, of which the optimum Pt:Ru ratio is 58:42 at.% at 25 deg. C and 50:50 at.% at 40 and 60 deg. C. This temperature dependence of the optimum Pt:Ru ratio is well explained by the relationship between the methanol oxidation reaction process and the temperature, which is reflected in the rate-determining steps considered from the activation energies. It should be noted that at 25-60 deg. C, the Pt-Ru/C with Pt:Ru = 50:50 at.% prepared by our sputtering method has the higher methanol oxidation activity than that of a commercially available sample with the identical overall Pt:Ru ratio. Consequently, the polygonal barrel-sputtering method

  12. Controllable pt nanoparticle deposition on carbon nanotubes as an anode catalyst for direct methanol fuel cells.

    Mu, Yongyan; Liang, Hanpu; Hu, Jinsong; Jiang, Li; Wan, Lijun

    2005-12-01

    We report a novel process to prepare well-dispersed Pt nanoparticles on CNTs. Pt nanoparticles, which were modified by the organic molecule triphenylphosphine, were deposited on multiwalled carbon nanotubes by the organic molecule, which acts as a cross linker. By manipulating the relative ratio of Pt nanoparticles and multiwalled carbon nanotubes in solution, Pt/CNT composites with different Pt content were achieved. The so-prepared Pt/CNT composite materials show higher electrocatalytic activity and better tolerance to poisoning species in methanol oxidation than the commercial E-TEK catalyst, which can be ascribed to the high dispersion of Pt nanoparticles on the multiwalled carbon nanotube surface.

  13. Preparation and electrocatalytic properties of Pt-SiO2 nanocatalysts for ethanol electrooxidation.

    Liu, B; Chen, J H; Zhong, X X; Cui, K Z; Zhou, H H; Kuang, Y F

    2007-03-01

    Due to their high stability in general acidic solutions, SiO(2) nanoparticles were selected as the second catalyst for ethanol oxidation in sulfuric acid aqueous solution. Pt-SiO(2) nanocatalysts were prepared in this paper. The micrography and elemental composition of Pt-SiO(2) nanoparticles were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. The electrocatalytic properties of Pt-SiO(2) nanocatalysts for ethanol oxidation were investigated by cyclic voltammetry. Under the same Pt loading mass and experimental conditions for ethanol oxidation, Pt-SiO(2) nanocatalysts show higher activity than PtRu/C (E-Tek), Pt/C (E-Tek), and Pt catalysts. Additionally, Pt-SiO(2) nanocatalysts possess good anti-poisoning ability. The results indicate that Pt-SiO(2) nanocatalysts may have good potential applications in direct ethanol fuel cells.

  14. Insights on the SO2 Poisoning of Pt3Co/VC and Pt/VC Fuel Cell Catalysts

    2010-01-01

    catalyst is performed at the cathode of proton exchange membrane fuel cells ( PEMFCs ) in order to link previously reported results at the elec- trode...stripping voltammetry and underpotential deposition (upd) of copper adatoms. Then the performance of PEMFC cathodes employing 30wt.% Pt3Co/VC and 50wt.% Pt/VC...proton exchange membrane fuel cells( PEMFCs )in order to link previously reported results at the elec- trode/solution interface to the FC environment. First

  15. Electric field mediated non-volatile tuning magnetism in CoPt/PMN-PT heterostructure for magnetoelectric memory devices

    Yang, Y. T.; Li, J.; Peng, X. L.; Wang, X. Q.; Wang, D. H.; Cao, Q. Q.; Du, Y. W.

    2016-02-01

    We report a power efficient non-volatile magnetoelectric memory in the CoPt/(011)PMN-PT heterostructure. Two reversible and stable electric field induced coercivity states (i.e., high-HC or low-HC) are obtained due to the strain mediated converse magnetoelectric effect. The reading process of the different coercive field information written by electric fields is demonstrated by using a magnetoresistance read head. This result shows good prospects in the application of novel multiferroic devices.

  16. 15 CFR 4a.3 - Classification levels.

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Classification levels. 4a.3 Section 4a.3 Commerce and Foreign Trade Office of the Secretary of Commerce CLASSIFICATION, DECLASSIFICATION... E.O. 12958. The levels established by E.O. 12958 (Top Secret, Secret, and Confidential) are the only...

  17. The Galeta oil spill: Pt. 2

    Burns, K.A.; Jorissen, D.; MacPherson, J.; Stoelting, M.; Tierney, J.; Yelle-Simmons, L.; Garrity, S.D.

    1994-01-01

    Sediment chemistry studies, undertaken as part of the long-term assessment of the Bahia las Minas (Panama) oil spill, showed the unexpected persistence of the full range of aromatic hydrocarbon residues of the spilled crude oil in anoxic muds of coastal mangroves. Mangrove muds served as long-term reservoirs for chronic contamination of contiguous coastal communities for over 5 years. One result of the repeated history of oil pollution incidents along this coast was an increased proportion of dead mangrove (Rhizophora mangle) roots in sediment cores which was related to contaminant loading and was detectable for at least 20 years after major oil spills. We suggest that this is the minimum time-scale that is to be expected for the loss of toxicity of oil trapped in muddy coastal habitats impacted by catastrophic oil spills. (author)

  18. Fission products in glasses. Pt. 2

    De, A.K.; Luckscheiter, B.; Malow, G.; Schiewer, E.

    1977-09-01

    Glass ceramics of different composition with high leach and impact resistance can be produced for fission product solidification. In contrast to commercial glass products, they consist of a number of crystalline phases and a residual glass phase. The major crystalline phase allows a classification into celsian, diopside, encryptite, and perovskite ceramics. They all are of special importance as host phases for long-lived fission products. The paper reports on relations between product composition and melting properties, viscosity, crystallization properties, and fixation capability for fission products. Further investigations deal with dimensional stability, impact resistance, thermal expansion, and thermal conductivity. The properties of the ceramics are compared with those of the basic products. The problems still to be solved with regard to further improvement and application of these products are discussed. (RB) [de

  19. The Galeta oil spill: Pt. 4

    Burns, K.A.; Yelle-Simmons, L.

    1994-01-01

    This paper gives the detailed compositions of oil residues in sediments and encrusting bivalves, and the changes over time. Initial weathering processes removed most of the volatile hydrocarbons and all market alkanes in oil adsorbed to surface sediments within 6 months after the spill. This initially fast rate of biodegradation was not maintained in the rate of disappearance of the aromatic hydrocarbons over time. Oil leaching out of heavily contaminated sediments was bioaccumulated in bivalves for at least 5 years. The organisms accumulated the whole range of alkylated polynuclear aromatic hydrocarbons (PAHs) in the naphthalene through the benzoperylene elution range, seemingly in proportion to what was leached from sediments. A change in the composition of the aromatics bioaccumulated at most sites in year 5 indicated depletion of the most soluble and most acutely toxic hydrocarbons in the readily leachable reservoirs. (author)

  20. First-principles study of nitric oxide oxidation on Pt(111) versus Pt overlayer on 3d transition metals

    Arevalo, Ryan Lacdao [Department of Precision Science and Technology and Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Escaño, Mary Clare Sison [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507 (Japan); Kasai, Hideaki, E-mail: kasai@dyn.ap.eng.osaka-u.ac.jp [Department of Precision Science and Technology and Applied Physics, Center for Atomic and Molecular Technologies, and Center for Continuing Professional Development, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2015-03-15

    Catalytic oxidation of NO to NO{sub 2} is a significant research interest for improving the quality of air through exhaust gas purification systems. In this paper, the authors studied this reaction on pure Pt and Pt overlayer on 3d transition metals using kinetic Monte Carlo simulations coupled with density functional theory based first principles calculations. The authors found that on the Pt(111) surface, NO oxidation proceeds via the Eley–Rideal mechanism, with O{sub 2} dissociative adsorption as the rate-determining step. The oxidation path via the Langmuir–Hinshelwood mechanism is very slow and does not significantly contribute to the overall reaction. However, in the Pt overlayer systems, the oxidation of NO on the surface is more thermodynamically and kinetically favorable compared to pure Pt. These findings are attributed to the weaker binding of O and NO on the Pt overlayer systems and the binding configuration of NO{sub 2} that promotes easier N-O bond formation. These results present insights for designing affordable and efficient catalysts for NO oxidation.

  1. Citric acid induced promoted dispersion of Pt on the support and enhanced catalytic activities for a Pt-based catalyst

    Cheng, Tianqiong; Wang, Jianli; Wang, Suning; Cui, Yajuan; Zhang, Hailong; Yan, Shuang; Yuan, Shandong; Chen, Yaoqiang

    2017-12-01

    Citric acid (CA), as the chelating agent, was introduced to obtain the enhanced Pt dispersion and catalytic activities for the Pt-based catalysts supported on oxygen-storage material. The role and content of CA were investigated systematically. It was found that the citric acid-assisted catalysts showed better Pt dispersion and smaller nanoparticle size of Pt. Thus, the catalyst had lower reduction temperature, preferable thermostability and possessed more oxidation state of Pt species under the oxidation atmosphere. The citric acid-induced fresh catalysts were excellent to convert CO and the corresponding aged ones exhibited higher activities for the elimination of all the target pollutants. Among the aged catalysts, P2-a (the mole ratio of Pt/CA is 2:1) presented the best performance. Particularly, compared with the reference sample (Pc-a), the light-off temperatures (T50) of NO, HC and CO for P2-a decreased by 39 °C, 42 °C and 72 °C, respectively, and the full-conversion temperatures (T90) of NO, HC and CO for P2-a decreased by 44 °C, 44 °C and 48 °C, respectively. Therefore, this work provides a facile and valid method to manufacture advanced catalysts for purification of the vehicle exhaust in the future.

  2. Influence of Pt thickness on magnetization reversal processes in (Pt/Co)3 multilayers with perpendicular anisotropy

    Belhi, R.; Adanlété Adjanoh, A.; Vogel, J.

    2012-01-01

    We present a detailed study of the magnetization reversal in perpendicularly magnetized (Pt/Co) 3 multilayers with different values of the platinum interlayer thickness t Pt . To study the magnetization reversal in our samples we combined measurements of relaxation curves with the direct visualization of domain structures. Magnetization reversal was dominated by domain wall propagation for t Pt =1 nm and by domain nucleation for t Pt =0.2 nm, while a mixed process was observed for t Pt =0.8 nm. We interpret our results within the framework of a model of thermally activated reversal where a distribution of activation energy barriers is taken into account. The reversal process was correlated with the energy barrier distribution. - Highlights: ► We show that the coercivity decreases with the Pt interlayer thickness. ► The reversal process is sensitively dependent on platinum interlayer thickness. ► We interpreted the results by taking into account of an energy barrier distribution. ► The reversal process was correlated with the energy barrier distribution width. ► The energy barrier distribution width varies linearly with the applied field.

  3. Microstructure and magnetic properties of nanocomposite FePt/MgO and FePt/Ag films

    Chen, S.C.; Kuo, P.C.; Sun, A.C.; Chou, C.Y.; Fang, Y.H.; Wu, T.H.

    2006-01-01

    An in-plane magnetic anisotropy of FePt film is obtained in the MgO 5 nm/FePt t nm/MgO 5 nm films (where t=5, 10 and 20 nm). Both the in-plane coercivity (H c- parallel ) and the perpendicular magnetic anisotropy of FePt films are increased when introducing an Ag-capped layer instead of MgO-capped layer. An in-plane coercivity is 3154 Oe for the MgO 5 nm/FePt 10 nm/MgO 5 nm film, and it can be increased to 4846 Oe as a 5 nm Ag-capped layer instead of MgO-capped layer. The transmission electron microscopy (TEM)-energy disperse spectrum (EDS) analysis shows that the Ag mainly distributed at the grain boundary of FePt, that leads the increase of the grain boundary energy, which will enhance coercivity and perpendicular magnetic anisotropy of FePt film

  4. Continuous Catalytic Hydrodeoxygenation of Guaiacol over Pt/SiO2 and Pt/H-MFI-90

    Melanie Hellinger

    2015-07-01

    Full Text Available Hydrodeoxygenation of guaiacol in the presence of 1-octanol was studied in a fixed-bed reactor under mild conditions (50–250 °C over platinum particles supported on silica (Pt/SiO2 and a zeolite with framework type MFI at a Si/Al-ratio of 45 (Pt/H-MFI-90. The deoxygenation selectivity strongly depended on the support and the temperature. Both guaiacol and octanol were rapidly deoxygenated in the presence of hydrogen over Pt/H-MFI-90 at 250 °C to cyclohexane and octane, respectively. In contrast, Pt/SiO2 mostly showed hydrogenation, but hardly any deoxygenation activity. The acidic sites of the MFI-90 support lead to improved deoxygenation performance at the mild temperature conditions of this study. Significant conversions under reaction conditions applied already occurred at temperatures of 200 °C. However, during long-term stability tests, the Pt/H-MFI-90 catalyst deactivated after more than 30 h, probably due to carbon deposition, whereas Pt/SiO2 was more stable. The catalytic activity of the zeolite catalyst could only partly be regained by calcination in air, as some of the acidic sites were lost.

  5. Magnetization dynamics of perpendicular exchange-biased (Pt/Co)-Pt-IrMn multilayers studied by MOKE microscopy and magnetometry

    Czapkiewicz, M.; Stobiecki, T.; Rak, R.; Zoladz, M.; Mietniowski, P. [Department of Electronics, AGH University of Science and Technology, 30-059 Krakow (Poland); Dijken, S. van [SFI Trinity Nanoscience Laboratory, Physics Department, Trinity College, Dublin 2 (Ireland)

    2006-01-01

    In this paper the dynamics of the magnetization reversal process in perpendicularly biased [20 Aa Pt/5 Aa Co]{sub 3}/t Aa Pt/100 Aa IrMn/20 Aa Pt multilayers with different Pt insertion layer thickness (0 Aa{<=}t{<=}12 Aa) is studied. The insertion of 1 Aa thick Pt enhances the exchange bias field (H{sub ex}) and for t>3 Aa H{sub ex} decreases exponentially with increasing Pt layer thickness. We show by magnetization relaxation measurements and direct observation of magnetic domains that magnetization reversal takes place by the nucleation of isolated cylindrical domains with a different nucleation site density in the forward and backward branches of the hysteresis loop. All the results were quantitatively analyzed using the Fatuzzo model for the dynamics of domain reversal processes. The activation energies for magnetization reversal by domain nucleation and domain propagation were determined. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Hydrogen peroxide treatment on ZnO substrates to investigate the characteristics of Pt and Pt oxide Schottky contacts

    Tsai, Chia-Hung; Hung, Chen-I; Yang, Cheng-Fu; Houng, Mau-Phon

    2010-01-01

    We utilize hydrogen peroxide (H 2 O 2 ) treatment on (0 0 0 1) ZnO substrates to investigate the characteristics of Pt and Pt oxide Schottky contacts (SCs). X-ray rocking curves show the mosaicity structure becomes larger after H 2 O 2 treatment. Photoluminescence (PL) spectra show the yellow-orange emission peaking at ∼576-580 nm with respect to deep level of oxygen interstitials introduced by H 2 O 2 treatment. The threshold formation of ZnO 2 resistive layer on H 2 O 2 -treated ZnO for 45 min is observed from grazing-incidence X-ray diffraction. The better electrical characteristic is performed by Pt oxide SC with the larger barrier height (1.09 eV) and the lower leakage current (9.52 x 10 -11 A/cm 2 at -2 V) than Pt SC on the H 2 O 2 -treated ZnO for 60 min. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometer (SIMS) examinations indicate the promoted interface oxide bonding and Zn outdiffusion for Pt oxide contact, different from Pt contact. Based on current-voltage, capacitance-voltage, X-ray diffraction, PL spectra, XPS, and SIMS results, the possible mechanism for effective rectifying characteristic and enhanced Schottky fbehavior is given.

  7. Radioactive material in residues of health services residues

    Costa R, A. Jr.; Recio, J.C.

    2006-01-01

    The work presents the operational actions developed by the one organ responsible regulator for the control of the material use radioactive in Brazil. Starting from the appearance of coming radioactive material of hospitals and clinical with services of nuclear medicine, material that that is picked up and transported in specific trucks for the gathering of residuals of hospital origin, and guided one it manufactures of treatment of residuals of services of health, where they suffer radiological monitoring before to guide them for final deposition in sanitary embankment, in the city of Sao Paulo, Brazil. The appearance of this radioactive material exposes a possible one violation of the norms that govern the procedures and practices in that sector in the country. (Author)

  8. Reformulation of Business Strategies for Increasing Sales of TIN Product Stabilizer at PT Timah Industri

    Sundoyo, Hadi; Hamsal, Mohammad

    2013-01-01

    PT. Timah Industri (PT TI) is a subsidiary of PT. Timah (Persero) Tbk which exploit comparative advantage of its parent company as the second largest tin producer in the world. With these advantages PT TI entered the downstream PVC stabilizer tin base. Starting from the difficulty of selling their products and then raised the question in inventory management. PT TI should immediately take strategic steps to save the tin chemical business continues to lose money from time to time. From the res...

  9. Influence of Pt Gate Electrode Thickness on the Hydrogen Gas Sensing Characteristics of Pt/In2O3/SiC Hetero-Junction Devices

    S. Kandasamy

    2007-09-01

    Full Text Available Hetero-junction Pt/In2O3/SiC devices with different Pt thickness (30, 50 and 90nm were fabricated and their hydrogen gas sensing characteristics have been studied. Pt and In2O3 thin films were deposited by laser ablation. The hydrogen sensitivity was found to increase with decreasing Pt electrode thickness. For devices with Pt thickness of 30 nm, the sensitivity gradually increased with increasing temperature and reached a maximum of 390 mV for 1% hydrogen in air at 530°C. Atomic force microscopy (AFM analysis revealed a decrease in Pt grain size and surface roughness for increasing Pt thickness. The relationship between the gas sensing performance and the Pt film thickness and surface morphology is discussed.

  10. Surface enrichment of Pt in stable Pt-Ir nano-alloy particles on MgAl 2 O 4 spinel in oxidizing atmosphere

    Li, Weizhen; Nie, Lei; Chen, Ying; Kovarik, Libor; Liu, Jun; Wang, Yong

    2017-04-01

    With the capability of MgAl2O4 spinel {111} nano-facets in stabilizing small Rh, Ir and Pt particles, bimetallic Ir-Pt catalysts on the same support were investigated, aiming at further lowering the catalyst cost by substituting expensive Pt with cheaper Ir in the bulk. Small Pt-Ir nano-alloy particles (< 2nm) were successfully stabilized on the spinel {111} nano-facets as expected. Interestingly, methanol oxidative dehydrogenation (ODH) rate on the surface Pt atoms increases with oxidizing aging but decreases upon reducing treatment, where Ir is almost inactive under the same reaction conditions. Up to three times enhancement in Pt exposure was achieved when the sample was oxidized at 800 °C in air for 1 week and subsequently reduced by H2 for 2 h, demonstrating successful surface enrichment of Pt on Pt-Ir nano-alloy particles. A dynamic stabilization mechanism involving wetting\

  11. Anti-prothrombin (aPT) and anti-phosphatidylserine/prothrombin (aPS/PT) antibodies and the risk of thrombosis in the antiphospholipid syndrome. A systematic review.

    Sciascia, Savino; Sanna, Giovanni; Murru, Veronica; Roccatello, Dario; Khamashta, Munther A; Bertolaccini, Maria Laura

    2014-02-01

    Antibodies to prothrombin are detected by directly coating prothrombin on irradiated ELISA plates (aPT) or by using the phosphatidylserine/prothrombin complex as antigen (aPS/PT). Although these antibodies have both been associated with antiphospholipid syndrome (APS) and a correlation between the two assays have been reported, it seems that aPT and aPS/PT belong to different populations of autoantibodies. It was our objective to systematically review the available evidence on aPT and aPS/PT antibodies and the risk of thrombosis in APS. Medline-reports published between 1988 and 2013 investigating aPT and aPS/PT as a risk factor for thrombosis were included. Whenever possible, antibody isotype(s) and site of thrombosis were analysed. This systematic review is based on available data from more than 7,000 patients and controls from 38 studies analysing aPT and 10 aPS/PT. Antibodies to prothrombin (both aPT and aPS/PT) increased the risk of thrombosis (odds ratio [OR] 2.3; 95% confidence interval [CI] 1.72-3.5). aPS/PT seemed to represent a stronger risk factor for thrombosis, both arterial and/or venous than aPT (OR 5.11; 95%CI 4.2-6.3 and OR 1.82; 95%CI 1.44-2.75, respectively). In conclusion, routine measurement of aPS/PT (but not aPT) might be useful in establishing the thrombotic risk of patients with previous thrombosis and/or systemic lupus erythematosus. Their inclusion as laboratory criteria for the APS should be indisputably further explored.

  12. Preparation of PtRu/C and PtSn/C electrocatalysts using electron beam irradiation for direct and ethanol fuel cell

    Silva, Dionisio Furtunato da

    2009-01-01

    PtRu/C and PtSn/C electrocatalysts were prepared using electron beam irradiation. The metal ions were dissolved in water/2-propanol and water/ethylene glycol solutions and the carbon support was added. The resulting mixtures were irradiated under stirring. The effect of water/ethylene glycol and water/2-propanol (v/v) ratio, Pt:Ru and Pt:Sn atomic ratios, the irradiation time and dose rate were studied. The obtained materials were characterized by Energy dispersive analysis of X-rays (EDX), X-ray diffraction (XRD), cyclic voltammetry (CV) and Moessbauer spectroscopy. The electro-oxidation of methanol and ethanol were studied by cyclic voltammetry and chronoamperometry using the thin porous coating technique. The electrocatalysts were also tested on the Direct Methanol and Ethanol Fuel Cells. PtRu/C electrocatalysts prepared in water/ethylene glycol showed Pt:Ru atomic ratios different from the nominal ones. The results suggested that part of the Ru(III) ions were not reduced. The obtained materials showed the face-centered cubic (fcc) structure of Pt and Pt alloys with crystallite sizes of 2-3 nm. PtRu/C electrocatalysts prepared in water/2-propanol showed Pt:Ru atomic ratios similar to the nominal ones. The obtained materials also showed the fcc structure of platinum and platinum alloys with crystallite sizes of 3-4 nm. PtSn/C electrocatalysts prepared in water/ethylene glycol and water/2-propanol showed Pt:Sn atomic ratios similar to the nominal ones. The obtained materials showed the platinum (fcc) phase with crystallite sizes in the range of 2 - 4 nm and a SnO 2 (cassiterite) phase. The obtained PtRu/C and PtSn/C electrocatalysts showed similar or superior performance for methanol and ethanol electro-oxidation compared to commercial PtRu/C (E-TEK) and PtSn/C (BASF) electrocatalysts. (author)

  13. Pt, PtCo and PtNi electrocatalysts prepared with mechanical alloying for oxygen reduction reaction in alkaline medium; Electrocatalizadores de Pt, PtCo y PtNi preparados por aleado mecanico para la reaccion de reduccion de oxigeno en medio alcalino

    Garcia-Contreras, M.A.; Fernandez-Valverde, S.M. [Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: miguel.garcia@inin.gob.mx; Vargas-Garcia, J.R. [ESIQIE-IPN, Mexico D.F. (Mexico

    2009-09-15

    Pt, PtCo and PtNi electrocatalysts were prepared using mechanical alloying and their electrocatalytic activity was investigated for oxygen reduction reaction (ORR) in KOH 0.5 M using cyclic voltametry and rotary disc electrode (RDE) techniques. The electrocatalysts were characterized using x-ray diffraction, sweep electron microscopy, dispersive x-ray transmission and chemical analysis. The physical characterization indicated that all the electrocatalysts are alloys formed by agglomerated particles composed of nanocrystals. The chemical analysis showed the presence of iron in the alloys. For the electrocatalytic evaluation, polarization curves and Koutecky-Levich and Tafel graphs were obtained to determine the kinetic parameters of the electrocatalysts in the study. With the same experimental conditions, the PtCo presented better electrocatalytic performance with a higher exchange current density. [Spanish] Se prepararon electrocatalizadores de Pt, PtCo y PtNi por aleado mecanico y se investigo su actividad electrocatalitica para la reaccion de reduccion de oxigeno (RRO) en KOH 0.5 M utilizando las tecnicas de Voltametria ciclica y Electrodo de Disco Rotatorio. Los electrocatalizadores se caracterizaron por difraccion de rayos X, Microscopia electronica de Barrido, de Transmision y analisis quimico por dispersion de rayos X. La caracterizacion fisica indico que todos los electrocatalizadores son aleaciones formadas de particulas aglomeradas, compuestas de nanocristales. El analisis quimico mostro la presencia de hierro en las aleaciones. Para la evaluacion electrocatalitica se obtuvieron curvas de polarizacion, graficas de Koutecky-Levich y de Tafel para determinar los parametros cineticos de los electrocatalizadores en estudio. En las mismas condiciones experimentales, el PtCo presento el mejor desempeno electrocatalitico con la densidad de corriente de intercambio mas alta.

  14. Improvement of plant reliability in PT. Badak LNG plant

    Achmad, S.; Somantri, A.

    1997-01-01

    PT. Badak's LNG sales commitment has been steadily increasing, therefore, there has been more emphasis to improve and maintain the LNG plant reliability. From plant operation historical records, Badak LNG plant experienced a high number of LNG process train trips and down time for 1977 through 1988. The highest annual number of LNG plant trips (50 times) occurred in 1983 and the longest LNG process train down time (1259 train-hours) occurred in 1988. Since 1989, PT. Badak has been able to reduce the number of LNG process train trips and down time significantly. In 1994 the number of LNG process train trips and was 18 times and the longest LNG process train down time was 377 train-hours. This plant reliability improvement was achieved by implementing plant reliability improvement programs beginning with the design of the new facilities and continuing with the maintenance and modification of the existing facilities. To improve reliability of the existing facilities, PT. Badak has been implementing comprehensive maintenance programs, to reduce the frequency and down time of the plant, such as Preventive and Predictive Maintenance as well as procurement material improvement since PT. Badak location is in a remote area. By implementing the comprehensive reliability maintenance, PT. Badak has been able to reduce the LNG process train trips to 18 and down time to 337 train hours in 1994 with the subsequent maintenance cost reduction. The average PT. Badak plant availability from 1985 to 1995 is 94.59%. New facilities were designed according to the established PT. Badak design philosophy, master plan and specification. Design of new facilities was modified to avoid certain problems from past experience. (au)

  15. The role of the anionic and cationic pt sites in the adsorption site preference of water and ethanol on defected Pt4/Pt(111) substrates: A density functional theory investigation within the D3 van der waals corrections

    Seminovski, Yohanna; Amaral, Rafael C.; Tereshchuk, Polina; Da Silva, Juarez L. F.

    2018-01-01

    Platinum (Pt) atoms in the bulk face-centered cubic structure have neutral charge because they are equivalent by symmetry, however, in clean Pt surfaces, the effective charge on Pt atoms can turn slightly negative (anionic) or positive (cationic) while increasing substantially in magnitude for defected (low-coordinated) Pt sites. The effective charge affect the adsorption properties of molecular species on Pt surfaces and it can compete in importance with the coupling of the substrate-molecule electronic states. Although several studies have been reported due to the importance of Pt for catalysis, our understanding of the role played by low-coordinated sites is still limited. Here, we employ density functional theory within the Perdew-Burke-Ernzerhof exchange-correlation functional and the D3 van der Waals (vdW) correction to investigate the role of the cationic and anionic Pt sites on the adsorption properties of ethanol and water on defected Pt4/Pt(111) substrates. Four substrates were carefully selected, namely, two two-dimensional (2D) Pt4 configurations (2D-strand and 2D-island) and two tri-dimensional (3D) Pt4 (3D-fcc and 3D-hcp), to understand the role of coordination, effective charge, and coupling of the electronic states in the adsorption properties. From the Bader charge analysis, we identified the cationic and anionic sites among the Pt atoms exposed to the vacuum region in the Pt4/Pt(111) substrates. We found that ethanol and water bind via the anionic O atoms to the low-coordinated defected Pt sites of the substrates, where the angle PtOH is nearly 100° for most configurations. In the 3D-fcc or 3D-hcp defected configurations, the lowest-coordinated Pt atoms are anionic, hence, those Pt sites are not preferable for the adsorption of O atoms. The charge transfer from water and ethanol to the Pt substrates has similar magnitude for all cases, which implies similar Coulomb contribution to the adsorption energy. Moreover, we found a correlation of the

  16. Spectroelectrochemical Study of Carbon Monoxide and Ethanol Oxidation on Pt/C, PtSn(3:1/C and PtSn(1:1/C Catalysts

    Rubén Rizo

    2016-09-01

    Full Text Available PtSn-based catalysts are one of the most active materials toward that contribute ethanol oxidation reaction (EOR. In order to gain a better understanding of the Sn influence on the carbon monoxide (principal catalyst poison and ethanol oxidation reactions in acidic media, a systematic spectroelectrochemical study was carried out. With this end, carbon-supported PtSnx (x = 0, 1/3 and 1 materials were synthesized and employed as anodic catalysts for both reactions. In situ Fourier transform infrared spectroscopy (FTIRS and differential electrochemical mass spectrometry (DEMS indicate that Sn diminishes the amount of bridge bonded CO (COB and greatly improves the CO tolerance of Pt-based catalysts. Regarding the effect of Sn loading on the EOR, it enhances the catalytic activity and decreases the onset potential. FTIRS and DEMS analysis indicate that the C-C bond scission occurs at low overpotentials and at the same potential values regardless of the Sn loading, although the amount of C-C bond breaking decreases with the rise of Sn in the catalytic material. Therefore, the elevated catalytic activity toward the EOR at PtSn-based electrodes is mainly associated with the improved CO tolerance and the incomplete oxidation of ethanol to form acetic acid and acetaldehyde species, causing the formation of a higher amount of both C2 products with the rise of Sn loading.

  17. Exchange bias energy in Co/Pt/IrMn multilayers with perpendicular and in-plane anisotropy

    Czapkiewicz, M.; Stobiecki, T.; Rak, R.; Zoladz, M.; Dijken, S. van

    2007-01-01

    The magnetization reversal process in perpendicularly biased [Pt/Co] 3 /d Pt Pt/IrMn and in-plane biased Co/d Pt Pt/IrMn multilayers with 0nm= Pt = Pt =0.1nm. In both cases, the existence of large exchange bias fields correlates with a high domain density during magnetization reversal. The interface exchange coupling energy is larger for the in-plane biased films than for the perpendicularly biased multilayers

  18. Methanol oxidation reaction activity of microwave irradiated and heat-treated Pt/Co and Pt/Ni nano-electrocatalysts

    Mathe, NR

    2014-11-01

    Full Text Available Bimetallic Pt nanoparticles were prepared by alloying Pt with the non-noble transition metals, Co and Ni, using a conventional heat-treatment (HT) method and microwaveirradiation (MW). The resulting samples were PteCo-Ht, PteNi-HT, PteCo, MW and Pt...

  19. CO oxidation on PtSn nanoparticle catalysts occurs at the interface of Pt and Sn oxide domains formed under reaction conditions

    Michalak, William D.; Krier, James M.; Alayoglu, Selim; Shin, Jae-Yoon; An, Kwangjin; Komvopoulos, Kyriakos; Liu, Zhi; Somorjai, Gabor A.

    2014-01-01

    The barrier to CO oxidation on Pt catalysts is the strongly bound adsorbed CO, which inhibits O2 adsorption and hinders CO2 formation. Using reaction studies and in situ X-ray spectroscopy with colloidally prepared, monodisperse ∼2 nm Pt and PtSn

  20. The effect of reducing agents on the electronic, magnetic and electrocatalytic properties of thiol-capped Pt/Co and Pt/Ni nanoparticles

    Mathe, NR

    2015-05-01

    Full Text Available The electronic, magnetic and electrocatalytic properties of bimetallic thiol-capped Pt/Co and Pt/Ni nanoparticles were synthesised using two reducing agents, NaBH(sub4) and N(sub2)H(sub4). X-ray diffraction analysis of the nanoparticles showed Pt...

  1. Electronic structure, thermodynamic properties and hydrogenation of LaPtIn and CePtIn compounds by ab-initio methods

    Jezierski, Andrzej; Szytuła, Andrzej

    2016-01-01

    The electronic structures and thermodynamic properties of LaPtIn and CePtIn are studied by means of ab-initio full-relativistic full-potential local orbital basis (FPLO) method within densities functional (DFT) methodologies. We have also examined the influence of hydrogen on the electronic structure and stability of CePtInH and LaPtInH systems. The positions of the hydrogen atoms have been found from the minimum of the total energy. Our calculations have shown that band structure and topology of the Fermi surfaces changed significantly during the hydrogenation. The thermodynamic properties (bulk modulus, Debye temperatures, constant pressure heat capacity) calculated in quasi-harmonic Debye-Grüneisen model are in a good agreement with the experimental data. We have applied different methods of the calculation of the equation of states (EOS) (Murnaghan, Birch-Murnaghan, Poirier–Tarantola, Vinet). The thermodynamic properties are presented for the pressure 0< P<9 GPa and the temperature range 0< T<300 K. - Highlights: • Full relativistic band structure of LaPtIn and CePtIn. • Fermi surface of LaPtIn, LaPtInH, CePtIn, CePtInH. • Effect of hydrogenation on the electronic structure of LaPtIn and CePtIn. • Thermodynamic properties in the quasi-harmonic Debye-Grüneisen model.

  2. The Cauchy method of residues

    Mitrinović, Dragoslav S

    1993-01-01

    Volume 1, i. e. the monograph The Cauchy Method of Residues - Theory and Applications published by D. Reidel Publishing Company in 1984 is the only book that covers all known applications of the calculus of residues. They range from the theory of equations, theory of numbers, matrix analysis, evaluation of real definite integrals, summation of finite and infinite series, expansions of functions into infinite series and products, ordinary and partial differential equations, mathematical and theoretical physics, to the calculus of finite differences and difference equations. The appearance of Volume 1 was acknowledged by the mathematical community. Favourable reviews and many private communications encouraged the authors to continue their work, the result being the present book, Volume 2, a sequel to Volume 1. We mention that Volume 1 is a revised, extended and updated translation of the book Cauchyjev raeun ostataka sa primenama published in Serbian by Nau~na knjiga, Belgrade in 1978, whereas the greater part ...

  3. Catalyst Architecture for Stable Single Atom Dispersion Enables Site-Specific Spectroscopic and Reactivity Measurements of CO Adsorbed to Pt Atoms, Oxidized Pt Clusters, and Metallic Pt Clusters on TiO2.

    DeRita, Leo; Dai, Sheng; Lopez-Zepeda, Kimberly; Pham, Nicholas; Graham, George W; Pan, Xiaoqing; Christopher, Phillip

    2017-10-11

    Oxide-supported precious metal nanoparticles are widely used industrial catalysts. Due to expense and rarity, developing synthetic protocols that reduce precious metal nanoparticle size and stabilize dispersed species is essential. Supported atomically dispersed, single precious metal atoms represent the most efficient metal utilization geometry, although debate regarding the catalytic activity of supported single precious atom species has arisen from difficulty in synthesizing homogeneous and stable single atom dispersions, and a lack of site-specific characterization approaches. We propose a catalyst architecture and characterization approach to overcome these limitations, by depositing ∼1 precious metal atom per support particle and characterizing structures by correlating scanning transmission electron microscopy imaging and CO probe molecule infrared spectroscopy. This is demonstrated for Pt supported on anatase TiO 2 . In these structures, isolated Pt atoms, Pt iso , remain stable through various conditions, and spectroscopic evidence suggests Pt iso species exist in homogeneous local environments. Comparing Pt iso to ∼1 nm preoxidized (Pt ox ) and prereduced (Pt metal ) Pt clusters on TiO 2 , we identify unique spectroscopic signatures of CO bound to each site and find CO adsorption energy is ordered: Pt iso ≪ Pt metal atoms bonded to TiO 2 and that Pt iso exhibits optimal reactivity because every atom is exposed for catalysis and forms an interfacial site with TiO 2 . This approach should be generally useful for studying the behavior of supported precious metal atoms.

  4. Effects of anisotropic diffusion and finite island sizes in homoepitaxial growth Pt on Pt(100)-hex

    Mortensen, Jens Jørgen; Linderoth, T.R.; Jacobsen, Karsten Wedel

    1998-01-01

    coverage regime. have been determined for substrate temperatures in the range T = 318-497 K and adatom deposition rates from R=4 x 10(-5) to 7 x 10(-3) site(-1) s(-1). The measurements are compared to the results of kinetic Monte Carlo (KMC) simulations and rate equation theory. The Pt(100)-hex surface...... exhibits a height modulation caused by the misfit between the topmost quasi-hexagonal layer and the quadratic substrate. resulting in a highly anisotropic large scale surface morphology with six-atom wide channels running along the [1(1) over bar0$] direction. From an autocorrelation analysis...... channels. Rate equations incorporating this effect are solved, and a scaling exponent of chi=1/3 is derived in contrast to the chi=1/4 obtained for a 1-D point-island model. (C) 1998 Elsevier Science B.V....

  5. Calcination/dissolution residue treatment

    Knight, R.C.; Creed, R.F.; Patello, G.K.; Hollenberg, G.W.; Buehler, M.F.; O'Rourke, S.M.; Visnapuu, A.; McLaughlin, D.F.

    1994-09-01

    Currently, high-level wastes are stored underground in steel-lined tanks at the Hanford site. Current plans call for the chemical pretreatment of these wastes before their immobilization in stable glass waste forms. One candidate pretreatment approach, calcination/dissolution, performs an alkaline fusion of the waste and creates a high-level/low-level partition based on the aqueous solubilities of the components of the product calcine. Literature and laboratory studies were conducted with the goal of finding a residue treatment technology that would decrease the quantity of high-level waste glass required following calcination/dissolution waste processing. Four elements, Fe, Ni, Bi, and U, postulated to be present in the high-level residue fraction were identified as being key to the quantity of high-level glass formed. Laboratory tests of the candidate technologies with simulant high-level residues showed reductive roasting followed by carbonyl volatilization to be successful in removing Fe, Ni, and Bi. Subsequent bench-scale tests on residues from calcination/dissolution processing of genuine Hanford Site tank waste showed Fe was separated with radioelement decontamination factors of 70 to 1,000 times with respect to total alpha activity. Thermodynamic analyses of the calcination of five typical Hanford Site tank waste compositions also were performed. The analyses showed sodium hydroxide to be the sole molten component in the waste calcine and emphasized the requirement for waste blending if fluid calcines are to be achieved. Other calcine phases identified in the thermodynamic analysis indicate the significant thermal reconstitution accomplished in calcination

  6. Residue management at Rocky Flats

    Olencz, J.

    1995-01-01

    Past plutonium production and manufacturing operations conducted at the Rocky Flats Environmental Technology Site (RFETS) produced a variety of plutonium-contaminated by-product materials. Residues are a category of these materials and were categorized as open-quotes materials in-processclose quotes to be recovered due to their inherent plutonium concentrations. In 1989 all RFETS plutonium production and manufacturing operations were curtailed. This report describes the management of plutonium bearing liquid and solid wastes

  7. Asymptotic properties of solvable PT-symmetric potentials

    Levai, G.

    2010-01-01

    Compete text of publication follows. The introduction of PT-symmetric quantum mechanics generated renewed interest in non-hermitian quantum mechanical systems in the past decade. PT symmetry means the invariance of a Hamiltonian under the simultaneous P space and T time reflection, the latter understood as complex conjugation. Considering the Schroedinger equation in one dimension, this corresponds to a potential with even real and odd imaginary components. This implies a delicate balance of emissive and absorptive regions that eventually manifests itself in properties that typically characterize real potentials, i.e. hermitian systems. These include partly or fully real energy spectrum and conserved (pseudo-)norm. A particularly notable feature of these systems is the spontaneous breakdown of PT symmetry, which typically occurs when the magnitude of the imaginary potential component exceeds a certain limit. At this point the real energy eigenvalues begin to merge pairwise and re-emerge as complex conjugate pairs. Another unusual property of PT-symmetric potentials is that they can, or sometimes have to be defined off the real x axis on trajectories that are symmetric with respect to the imaginary x axis. After more than a decade of theoretical investigations a remarkable recent development was the experimental verification of the existence of PT-symmetric systems in nature and the occurrence of spontaneous PT symmetry breaking in them. The experimental setup was a waveguide containing regions where loss and gain of flux occurred in a set out prescribed by PT symmetry. These experimental developments require the study of PT -symmetric potentials with various asymptotics, in which, furthermore, the complex potential component is finite in its range and/or its magnitude. Having in mind that PT symmetry allows for a wider variety of asymptotic properties than hermeticity, we studied three exactly solvable PT-symmetric potentials and compared their scattering and bound

  8. Residual life management. Maintenance improvement

    Sainero Garcia, J.; Hevia Ruperez, F.

    1995-01-01

    The terms Residual Life Management, Life Cycle Management and Long-Term Management are synonymous with a concept which aims to establish efficient maintenance for the profitable and safe operation of a power plant for as long as possible. A Residual Life Management programme comprises a number of stages, of which Maintenance Evaluation focuses on how power plant maintenance practices allow the mitigation and control of component ageing. with this objective in mind, a methodology has been developed for the analysis of potential degradative phenomena acting on critical components in terms of normal power plant maintenance practices. This methodology applied to maintenance evaluation enables the setting out of a maintenance programme based on the Life Management concept, and the programme's subsequent up-dating to allow for new techniques and methods. Initial applications have shown that although, in general terms, power plant maintenance is efficient, the way in which Residual Life Management is approached requires changes in maintenance practices. These changes range from modifications to existing inspection and surveillance methods or the establishment of new ones, to the monitoring of trends or the performance of additional studies, the purpose of which is to provide an accurate evaluation of the condition of the installations and the possibility of life extension. (Author)

  9. Survival of T4aN0 and T3N+ laryngeal cancer patients: a retrospective institutional study and systematic review.

    Khoueir, Nadim; Matar, Nayla; Farah, Chadi; Francis, Evana; Tabchy, Bassam; Haddad, Amine

    2015-01-01

    We aim to assess the correlation of tumor and nodal staging to survival in pT3N+ and T4aN0 laryngeal cancer with subgroup analysis within stage IVa (pT4N0 and pT3N2). Retrospective cohort study with systematic review of the literature. Hotel Dieu de France University Hospital (tertiary referral center). Laryngeal cancer patients' registries were reviewed from 1998 to 2012 selecting pT3N+ and pT4aN0 patients treated by primary total layngectomy. Overall survivals were compared using Log rank and Kaplan-Meier analysis. A systematic review was performed by 2 reviewers including all the articles reporting the outcome of these categories of patients. Online databases, including PubMed and EMBASE, were used. Reference sections of identified studies were examined for additional articles. Thirteen T3N+ patients and 19 T4aN0 patients treated by primary total laryngectomy were included. Five-year overall survival for T3N+, T3N2 and T4aN0 was respectively 33%, 32.1% and 73.7%. Due to the small sample, the difference was not significant. The systematic review revealed three articles reporting overall survival outcome for the T4N0 group and 6 articles for the T3N+. At 5years, the survival ranged from 62.5% to 73% in T4N0 and from 32.2% to 77% in T3N+. In advanced stage laryngeal cancer, T4aN0 tends toward a better survival than T3N+ especially when compared to T3N2 although they are grouped in the same TNM stage IVa. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Exchange interaction in MnPt/FeCo sputtered multilayers

    Honda, S.; Nawate, M.; Norikane, T.

    2000-01-01

    MnPt single-layer films have been prepared on glass substrates by RF magnetron sputtering for studying the composition dependencies of resistivity and crystalline structure. In the as-deposited state, the resistivity increases with Mn content and reaches the maximum at 69 at%. By annealing, the resistivity of the films having the Mn content around 51 at% increases, closely relating to the growth of the ordered CuAu FCT-type MnPt crystals. For the both film structures of the glass/Cu/FeCo/MnPt/Cu and the glass/MnPt/FeCo/Cu, which have been sputter-deposited on glass substrates, the exchange interaction between MnPt and FeCo layers, and the coercivity of the FeCo layer have been examined as functions of the Mn content, the layer thickness and the annealing temperature. In the as-deposited state, the exchange field (H ex ) is nearly zero up to 75 at% of Mn content, above which the value of H ex increases and shows the maximum at 85 at%, in which the blocking temperature is about 100 deg. C. By annealing, the value of H ex increases for the films of Mn content around 40-60 at%, exhibiting the higher blocking temperature than 360 deg. C. The temperature stability has also been examined using the Rutherford backscattering spectrometry

  11. Dynamics of Disordered PI-PtBS Diblock Copolymer

    Watanabe, Hiroshi

    2009-03-01

    Viscoelastic (G^*) and dielectric (ɛ'') data were examined for a LCST-type diblock copolymer composed of polyisoprene (PI; M = 53K) and poly(p-tert- butyl styrene) (PtBS; M = 42K) blocks disordered at T PtBS block at low T and the dynamic heterogeneity due to PtBS was effectively quenched to give a frictional nonuniformity for the PI block relaxation. The ɛ'' data were thermo-rheologically complex at low T, partly due to this nonuniformity. However, the block connectivity could have also led to the complexity. For testing this effect, the ɛ'' data were reduced at the iso- frictional state defined with respect to bulk PI. In this state, the ɛ'' data of the copolymer at low and high T, respectively, were close to the data for the star-branched and linear bulk PI. Thus, the PI block appeared to be effectively tethered in space at low T thereby behaving similarly to the star arm while the PI block tended to move cooperatively with the PtBS block at high T to behave similarly to the linear PI, which led to the complexity of the ɛ'' data. The PtBS block also exhibited the complexity (noted from the G^* data), which was well correlated with the complexity of the PI block.

  12. Surface and electrochemical characterization of electrodeposited PtRu alloys

    Richarz, Frank; Wohlmann, Bernd; Vogel, Ulrich; Hoffschulz, Henning; Wandelt, Klaus

    1995-07-01

    PtRu alloys of different compositions were electrodeposited on Au. Twelve alloys between 0% and 100% Pt were characterized with surface sensitive spectroscopies (XPS, LEIS) after transfer from an electrochemical cell to an ultra high vaccum chamber without contact to air. The composition of the thus prepared alloys showed a linear dependence on the concentrations of the deposition solution, but was Pt-enriched both in the bulk and (even more so) at the surface. During the electrochemical reduction of the metal cations, sulfur from the supporting electrolyte 1N H 2SO 4 was found to be incorporated into the electrodes. Cyclic voltammetry was used for the determination of the electrocatalytic activity of the electrodes for the oxidation of carbon monoxide. The highest activity for this oxidation as measured by the (peak) potential of the CO oxidation cyclovoltammograms was found for a surface concentration of ˜ 50%Pt. The asymmetry of this "activity curve" (oxidation potential versus Pt surface concentration) is tentatively explained in terms of a surface structural phase separation.

  13. Metal Phosphate-Supported Pt Catalysts for CO Oxidation

    Xiaoshuang Qian

    2014-12-01

    Full Text Available Oxides (such as SiO2, TiO2, ZrO2, Al2O3, Fe2O3, CeO2 have often been used to prepare supported Pt catalysts for CO oxidation and other reactions, whereas metal phosphate-supported Pt catalysts for CO oxidation were rarely reported. Metal phosphates are a family of metal salts with high thermal stability and acid-base properties. Hydroxyapatite (Ca10(PO46(OH2, denoted as Ca-P-O here also has rich hydroxyls. Here we report a series of metal phosphate-supported Pt (Pt/M-P-O, M = Mg, Al, Ca, Fe, Co, Zn, La catalysts for CO oxidation. Pt/Ca-P-O shows the highest activity. Relevant characterization was conducted using N2 adsorption-desorption, inductively coupled plasma (ICP atomic emission spectroscopy, X-ray diffraction (XRD, transmission electron microscopy (TEM, CO2 temperature-programmed desorption (CO2-TPD, X-ray photoelectron spectroscopy (XPS, and H2 temperature-programmed reduction (H2-TPR. This work furnishes a new catalyst system for CO oxidation and other possible reactions.

  14. PT Symmetry and QCD: Finite Temperature and Density

    Michael C. Ogilvie

    2009-04-01

    Full Text Available The relevance of PT symmetry to quantum chromodynamics (QCD, the gauge theory of the strong interactions, is explored in the context of finite temperature and density. Two significant problems in QCD are studied: the sign problem of finite-density QCD, and the problem of confinement. It is proven that the effective action for heavy quarks at finite density is PT-symmetric. For the case of 1+1 dimensions, the PT-symmetric Hamiltonian, although not Hermitian, has real eigenvalues for a range of values of the chemical potential μ, solving the sign problem for this model. The effective action for heavy quarks is part of a potentially large class of generalized sine-Gordon models which are non-Hermitian but are PT-symmetric. Generalized sine-Gordon models also occur naturally in gauge theories in which magnetic monopoles lead to confinement. We explore gauge theories where monopoles cause confinement at arbitrarily high temperatures. Several different classes of monopole gases exist, with each class leading to different string tension scaling laws. For one class of monopole gas models, the PT-symmetric affine Toda field theory emerges naturally as the effective theory. This in turn leads to sine-law scaling for string tensions, a behavior consistent with lattice simulations.

  15. Fabrication and surface transformation of FePt nanoparticle monolayer

    Wang Ying; Ding Baojun; Li Hua; Zhang Xiaoyan; Cai Bingchu; Zhang Yafei

    2007-01-01

    The monolayer of FePt nanoparticles with the mean size of ∼4 nm was fabricated on a glass substrate by the Langmuir--Blodgett (LB) technology. The monolayer of FePt nanoparticles has a smooth surface and a high density structure as shown by the AFM image. The array structure of FePt nanoparticles on the surface of the film is clearly with a cubic symmetry in appropriate condition. Small-angle X-ray diffraction (SXRD) measurement of multilayer structure for the FePt nanoparticles has indicated that the superlattices consist of well-defined smooth layers. The transfer of nanoparticle layers onto a solid substrate surface was quite efficient for the first few layers, exhibiting a proportional increase of optical absorption in the UV-vis range. This results potentially opens up a new approach to the long-range ordered array of FePt nanoparticles capped by organic molecules on substrate and provide a promising thin film, which may exhibit the excellent ultra-high density magnetic recording properties

  16. Gamma Radiolytic Formation of Alloyed Ag-Pt Nanocolloids

    M. K. Temgire

    2011-01-01

    Full Text Available Colloidal dispersions of Ag-Pt composite nanoparticles were prepared by gamma radiolysis technique in the presence of nonionic surfactant Brij'97. Simultaneous as well as sequential reduction methods were employed in order to study the structural formation of Ag-Pt bimetallic clusters. Similar shape and trend was observed in optical spectra for both methods. Radiolysis yielded nearly spherical Ag-Pt bimetallic clusters by use of AgNO3 instead of AgClO4. The disappearance of the silver resonance and the simultaneous growth of the 260 nm resonance are independent of cluster structure and degree of alloying. To understand formation of Ag-Pt aggregate, the optical studies were also done as a function of amount of dose absorbed, concentration of surfactant, that is, Brij'97. The shape of the absorption spectrum did not change with increase in gamma radiation dose. TEM analysis exhibited fine dispersions of Ag-Pt clusters surrounded by a mantle when capped with Brij'97. The particle size obtained was in the range of 5–9 nm. On the basis of optical, XRD, and TEM analysis, alloy formation is discussed.

  17. DFT Study of Optical Properties of Pt-based Complexes

    Oprea, Corneliu I.; Dumbravǎ, Anca; Moscalu, Florin; Nicolaides, Atnanassios; Gîrţu, Mihai A.

    2010-01-01

    We report Density Functional Theory (DFT) calculations providing the geometrical and electronic structures, as well as the vibrational and optical properties of the homologous series of Pt-pyramidalized olefin complexes (CH2)n-(C8H10)Pt(PH3)2, where n = 0, 1, and 2, in their neutral and oxidized states. All complexes were geometry optimized for the singlet ground state in vacuum using DFT methods with B3LYP exchange-correlation functional and the Effective Core Potential LANL2DZ basis set, within the frame of Gaussian03 quantum chemistry package. We find the coordination geometry of Pt to be distorted square planar, with dihedral angles ranging from 0°, for n = 0 and 1, which have C2V symmetry to 3.4°, for n = 2 with C2 symmetry. The Mulliken charge analysis allows a discussion of the oxidation state of the Pt ion. Electronic transitions were calculated at the same level of theory by means of Time Dependant-DFT. For n = 2 the electronic absorption bands are located in the UV region of the spectrum, the transitions being assigned to metal to ligand charge transfers. The relevance of these Pt-based compounds as possible pigments for dye-sensitized solar cells is discussed.

  18. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO2 reforming of methane

    Biausque, Gregory; Laveille, Paco; Anjum, Dalaver H.; Caps, Valerie; Basset, Jean-Marie

    2015-01-01

    Embodiments of the present disclosure provide for NiPt nanoparticles, compositions and supports including NiPt nanoparticles, methods of making NiPt nanoparticles, methods of supporting NiPt nanoparticles, methods of using NiPt nanoparticles, and the like.

  19. Methods to synthesize NiPt bimetallic nanoparticles by a reversed-phase microemulsion, deposition of NiPt bimetallic nanoparticles on a support, and application of the supported catalyst for CO2 reforming of methane

    Biausque, Gregory

    2015-09-24

    Embodiments of the present disclosure provide for NiPt nanoparticles, compositions and supports including NiPt nanoparticles, methods of making NiPt nanoparticles, methods of supporting NiPt nanoparticles, methods of using NiPt nanoparticles, and the like.

  20. Carbon Corrosion at Pt/C Interface in Proton Exchange Membrane Fuel Cell Environment

    Choi, Min Ho; Beam, Won Jin; Park, Chan Jin

    2010-01-01

    This study examined the carbon corrosion at Pt/C interface in proton exchange membrane fuel cell environment. The Pt nano particles were electrodeposited on carbon substrate, and then the corrosion behavior of the carbon electrode was examined. The carbon electrodes with Pt nano electrodeposits exhibited the higher oxidation rate and lower oxidation overpotential compared with that of the electrode without Pt. This phenomenon was more active at 75 .deg. C than 25 .deg. C. In addition, the current transients and the corresponding power spectral density (PSD) of the carbon electrodes with Pt nano electrodeposits were much higher than those of the electrode without Pt. The carbon corrosion at Pt/C interface was highly accelerated by Pt nano electrodeposits. Furthermore, the polarization and power density curves of PEMFC showed degradation in the performance due to a deterioration of cathode catalyst material and Pt dissolution

  1. Porous graphene supported Pt catalysts for proton exchange membrane fuel cells

    Cheng, Kun; He, Daping; Peng, Tao; Lv, Haifeng; Pan, Mu; Mu, Shichun

    2014-01-01

    Graphene nanosheet (GNS) has a remarkably high ratio of surface area to thickness and intense inter-sheet aggregation, which heavily resist mass diffusion in vertical orientation. Here, we establish a fast-speed mass diffusion passage by creating pores in GNS, and the corresponding Pt catalyst (Pt/rPGO) displays 15.5 times mass diffusion rate than that of the pristine GNS supported Pt catalyst (Pt/rGO). Thus, the Pt/rPGO catalyst exhibits 1.5 times increase in Pt mass activity toward oxygen reduction reaction compared with the Pt/rGO. Significantly, after H 2 thermal treatment, the mass activity of the Pt/rPGO further increases to 1.9 times that of the Pt/rGO, and its electrochemical stability is also greatly improved

  2. Very high coercivities of top-layer diffusion Au/FePt thin films

    Yuan, F.T.; Chen, S.K.; Liao, W.M.; Hsu, C.W.; Hsiao, S.N.; Chang, W.C.

    2006-01-01

    The Au/FePt samples were prepared by depositing a gold cap layer at room temperature onto a fully ordered FePt layer, followed by an annealing at 800 deg. C for the purpose of interlayer diffusion. After the deposition of the gold layer and the high-temperature annealing, the gold atoms do not dissolve into the FePt Ll 0 lattice. Compared with the continuous FePt film, the TEM photos of the bilayer Au(60 nm)/FePt(60 nm) show a granular structure with FePt particles embedded in Au matrix. The coercivity of Au(60 nm)/FePt(60 nm) sample is 23.5 kOe, which is 85% larger than that of the FePt film without Au top layer. The enhancement in coercivity can be attributed to the formation of isolated structure of FePt ordered phase

  3. Characterisation and management of concrete grinding residuals.

    Kluge, Matt; Gupta, Nautasha; Watts, Ben; Chadik, Paul A; Ferraro, Christopher; Townsend, Timothy G

    2018-02-01

    Concrete grinding residue is the waste product resulting from the grinding, cutting, and resurfacing of concrete pavement. Potential beneficial applications for concrete grinding residue include use as a soil amendment and as a construction material, including as an additive to Portland cement concrete. Concrete grinding residue exhibits a high pH, and though not hazardous, it is sufficiently elevated that precautions need to be taken around aquatic ecosystems. Best management practices and state regulations focus on reducing the impact on such aquatic environment. Heavy metals are present in concrete grinding residue, but concentrations are of the same magnitude as typically recycled concrete residuals. The chemical composition of concrete grinding residue makes it a useful product for some soil amendment purposes at appropriate land application rates. The presence of unreacted concrete in concrete grinding residue was examined for potential use as partial replacement of cement in new concrete. Testing of Florida concrete grinding residue revealed no dramatic reactivity or improvement in mortar strength.

  4. FINITE ELEMENT MODEL FOR PREDICTING RESIDUAL ...

    FINITE ELEMENT MODEL FOR PREDICTING RESIDUAL STRESSES IN ... the transverse residual stress in the x-direction (σx) had a maximum value of 375MPa ... the finite element method are in fair agreement with the experimental results.

  5. Polychlorinated Biphenyls (PCB) Residue Effects Database

    U.S. Environmental Protection Agency — The PCB Residue Effects (PCBRes) Database was developed to assist scientists and risk assessors in correlating PCB and dioxin-like compound residues with toxic...

  6. Nuclear receptor 4A (NR4A) family - orphans no more.

    Safe, Stephen; Jin, Un-Ho; Morpurgo, Benjamin; Abudayyeh, Ala; Singh, Mandip; Tjalkens, Ronald B

    2016-03-01

    The orphan nuclear receptors NR4A1, NR4A2 and NR4A3 are immediate early genes induced by multiple stressors, and the NR4A receptors play an important role in maintaining cellular homeostasis and disease. There is increasing evidence for the role of these receptors in metabolic, cardiovascular and neurological functions and also in inflammation and inflammatory diseases and in immune functions and cancer. Despite the similarities of NR4A1, NR4A2 and NR4A3 and their interactions with common cis-genomic elements, they exhibit unique activities and cell-/tissue-specific functions. Although endogenous ligands for NR4A receptors have not been identified, there is increasing evidence that structurally-diverse synthetic molecules can directly interact with the ligand binding domain of NR4A1 and act as agonists or antagonists, and ligands for NR4A2 and NR4A3 have also been identified. Since NR4A receptors are key factors in multiple diseases, there are opportunities for the future development of NR4A ligands for clinical applications in treating multiple health problems including metabolic, neurologic and cardiovascular diseases, other inflammatory conditions, and cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Simple preparations of Pd6Cl12, Pt6Cl12, and Qn[Pt2Cl8+n], n=1, 2 (Q=TBA+, PPN+) and structural characterization of [TBA][Pt2Cl9] and [PPN]2[Pt2Cl10].C7H8.

    Dell'Amico, Daniela Belli; Calderazzo, Fausto; Marchetti, Fabio; Ramello, Stefano; Samaritani, Simona

    2008-02-04

    The hexanuclear Pd6Cl12, i.e., the crystal phase classified as beta-PdCl2, was obtained by reacting [TBA]2[Pd2Cl6] with AlCl3 (or FeCl3) in CH2Cl2. The action of AlCl3 on PtCl42-, followed by digestion of the resulting solid in 1,2-C2H4Cl2 (DCE), CHCl3, or benzene, produced Pt6Cl12.DCE, Pt6Cl12.CHCl3, or Pt6Cl12.C6H6, respectively. Treating [TBA]2[PtCl6] with a slight excess of AlCl3 afforded [TBA][Pt2Cl9], whose anion was established crystallographically to be constituted by two "PtCl6" octahedra sharing a face. Dehydration of H2PtCl6.nH2O with SOCl2 gave an amorphous compound closely analyzing as PtCl4, reactive with [Q]Cl in SOCl2 to yield [Q][Pt2Cl9] or [Q]2[Pt2Cl10], depending on the [Q]Cl/Pt molar ratio (Q=TBA+, PPN+). A single-crystal X-ray diffraction study has shown [PPN]2[Pt2Cl10].C7H8 to contain dinuclear anions formed by two edge-sharing PtCl6 octahedra.

  8. Pt-Ni and Pt-M-Ni (M = Ru, Sn Anode Catalysts for Low-Temperature Acidic Direct Alcohol Fuel Cells: A Review

    Ermete Antolini

    2017-01-01

    Full Text Available In view of a possible use as anode materials in acidic direct alcohol fuel cells, the electro-catalytic activity of Pt-Ni and Pt-M-Ni (M = Ru, Sn catalysts for methanol and ethanol oxidation has been widely investigated. An overview of literature data regarding the effect of the addition of Ni to Pt and Pt-M on the methanol and ethanol oxidation activity in acid environment of the resulting binary and ternary Ni-containing Pt-based catalysts is presented, highlighting the effect of alloyed and non-alloyed nickel on the catalytic activity of these materials.

  9. PtSi Clustering in Silicon Probed by Transport Spectroscopy

    Massimo Mongillo

    2013-12-01

    Full Text Available Metal silicides formed by means of thermal annealing processes are employed as contact materials in microelectronics. Control of the structure of silicide/silicon interfaces becomes a critical issue when the characteristic size of the device is reduced below a few tens of nanometers. Here, we report on silicide clustering occurring within the channel of PtSi/Si/PtSi Schottky-barrier transistors. This phenomenon is investigated through atomistic simulations and low-temperature resonant-tunneling spectroscopy. Our results provide evidence for the segregation of a PtSi cluster with a diameter of a few nanometers from the silicide contact. The cluster acts as a metallic quantum dot giving rise to distinct signatures of quantum transport through its discrete energy states.

  10. Random matrix ensembles for PT-symmetric systems

    Graefe, Eva-Maria; Mudute-Ndumbe, Steve; Taylor, Matthew

    2015-01-01

    Recently much effort has been made towards the introduction of non-Hermitian random matrix models respecting PT-symmetry. Here we show that there is a one-to-one correspondence between complex PT-symmetric matrices and split-complex and split-quaternionic versions of Hermitian matrices. We introduce two new random matrix ensembles of (a) Gaussian split-complex Hermitian; and (b) Gaussian split-quaternionic Hermitian matrices, of arbitrary sizes. We conjecture that these ensembles represent universality classes for PT-symmetric matrices. For the case of 2 × 2 matrices we derive analytic expressions for the joint probability distributions of the eigenvalues, the one-level densities and the level spacings in the case of real eigenvalues. (fast track communication)

  11. STRATEGI PENINGKATAN DAYA SAING RUMAH POTONG AYAM PT XYZ

    Arli Arli

    2012-07-01

    Full Text Available ABSTRACTThe objectives of this study were (1 analyzing the role of parties in the value chain that affect PT XYZ competitiveness, (2 identifying the RPA PT XYZ  stakeholders’ key players, (3 analyzing internal and external (IE factors that affects the competitiveness of RPA PT XYZ , (4 formulating strategic long term objectives and goals to increase the competitiveness of RPA PT XYZ , (5 analyzing strategies’ priorities and alternatives to improve the competitiveness of RPA PT XYZ . The method used in this study was descriptive analysis. The analysis tools used in this study were global value chain, stakeholders’ analysis, internal factor evaluation, external factor evaluation, IE Matrix, SWOT, and quantitative strategic planning matrix. Based on the results of global value chain analysis, stakeholders analysis, internal and external analysis, and the company’s visions and missions, the long term objectives are (a to provide value added for customers, (b to maximize business operation’s profit, (c to increase stakeholders’ welfare, (d to operate a sustainable business operation. Results on the IE Matrix and the SWOT analysis, the strategies that can be used to achieve the strategic long term objectives and goals are (a to increase the effectiveness and the efficiencies of the supply chain management; (b to implement performance evaluation on employees and business partners; (c to strengthen the company’s image as a high quality domestic chicken-based food producer in Indonesia; (d to enhance researches and developments; (e to build strategic alliances with external live chicken suppliers; (f promote the importance of animal protein consumption to Indonesian society. Three priority strategies resulted from QSPM analysis are create enhancing the effectiveness and efficiency of the supply chain, implementing performance evaluation on employees and business partners, and strengthen the company’s image as a high quality domestic

  12. Solitons in PT-symmetric potential with competing nonlinearity

    Khare, Avinash; Al-Marzoug, S.M.; Bahlouli, Hocine

    2012-01-01

    We investigate the effect of competing nonlinearities on beam dynamics in PT-symmetric potentials. In particular, we consider the stationary nonlinear Schrödinger equation (NLSE) in one dimension with competing cubic and generalized nonlinearity in the presence of a PT-symmetric potential. Closed form solutions for localized states are obtained. These solitons are shown to be stable over a wide range of potential parameters. The transverse power flow associated with these complex solitons is also examined. -- Highlights: ► Effect of competing nonlinearities on beam dynamics in PT-symmetric potentials. ► Closed form solutions for localized states are. ► The transverse power flow associated with these complex solitons is also examined.

  13. High $p_{T}$ physics in the heavy ion era

    AUTHOR|(CDS)2069922

    2013-01-01

    Aimed at graduate students and researchers in the field of high-energy nuclear physics, this book provides an overview of the basic concepts of large transverse momentum particle physics, with a focus on pQCD phenomena. It examines high $p_{T}$ probes of relativistic heavy-ion collisions and will serve as a handbook for those working on RHIC and LHC data analyses. Starting with an introduction and review of the field, the authors look at basic observables and experimental techniques, concentrating on relativistic particle kinematics, before moving onto a discussion about the origins of high $p_{T}$ physics. The main features of high $p_{T}$ physics are placed within a historical context and the authors adopt an experimental outlook, highlighting the most important discoveries leading up to the foundation of modern QCD theory. Advanced methods are described in detail, making this book especially useful for newcomers to the field.

  14. EXCEPTIONAL POINTS IN OPEN AND PT-SYMMETRIC SYSTEMS

    Hichem Eleuch

    2014-04-01

    Full Text Available Exceptional points (EPs determine the dynamics of open quantum systems and cause also PT symmetry breaking in PT symmetric systems. From a mathematical point of view, this is caused by the fact that the phases of the wavefunctions (eigenfunctions of a non-Hermitian Hamiltonian relative to one another are not rigid when an EP is approached. The system is therefore able to align with the environment to which it is coupled and, consequently, rigorous changes of the system properties may occur. We compare analytically as well as numerically the eigenvalues and eigenfunctions of a 2 × 2 matrix that is characteristic either of open quantum systems at high level density or of PT symmetric optical lattices. In both cases, the results show clearly the influence of the environment on the system in the neighborhood of EPs. Although the systems are very different from one another, the eigenvalues and eigenfunctions indicate the same characteristic features.

  15. Electrochemical oxidation of methanol on Pt3Co bulk alloy

    S. LJ. GOJKOVIC

    2003-11-01

    Full Text Available The electrochemical oxidation of methanol was investigated on a Pt3Co bulk alloy in acid solutions. Kinetic parameters such as transfer coefficient, reaction orders with respect to methanol and H+ ions and energy of activation were determined. It was found that the rate of methanol oxidation is significantly diminished by rotation of the electrode. This effect was attributed to the diffusion of formaldehyde and formic acid from the electrode surface. Stirring of the electrolyte also influenced the kinetic parameters of the reaction. It was speculated that the predominant reaction pathway and rate determining step are different in the quiescent and in the stirred electrolyte. Cobalt did not show a promoting effect on the rate of methanol oxidation on the Pt3Co bulk alloy with respect to a pure Pt surface.

  16. Misfit strain phase diagrams of epitaxial PMN–PT films

    Khakpash, N.; Khassaf, H.; Rossetti, G. A. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Alpay, S. P., E-mail: p.alpay@ims.uconn.edu [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-02-23

    Misfit strain–temperature phase diagrams of three compositions of (001) pseudocubic (1 − x)·Pb (Mg{sub l/3}Nb{sub 2/3})O{sub 3} − x·PbTiO{sub 3} (PMN–PT) thin films are computed using a phenomenological model. Two (x = 0.30, 0.42) are located near the morphotropic phase boundary (MPB) of bulk PMN–PT at room temperature (RT) and one (x = 0.70) is located far from the MPB. The results show that it is possible to stabilize an adaptive monoclinic phase over a wide range of misfit strains. At RT, the stability region of this phase is much larger for PMN–PT compared to barium strontium titanate and lead zirconate titanate films.

  17. HFI of {sup 13}O in Pt: anomalous Knight Shift

    Tanigaki, M.; Matsuta, K.; Fukuda, M. [Osaka Univ., Toyonaka (Japan). Dept. of Physics] [and others

    1996-04-01

    The Knight Shift K and the spin relaxation time T{sub 1} for interstitial impurities implanted in metals are important clues to investigate the electronic structure of the metals. Because Pt has very low local electron density around the Fermi level for interstitial impurities, Pt is known as the unique implantation medium in which the implanted nuclei show small K and large T{sub 1}. The recent development of the technique of polarized radioactive nuclear beams widen the variety of probe nuclei. In the present paper, we have studied the hyperfine interactions of {sup 13}O(I{sup {pi}}=3/2{sup -}, T{sub 1/2}=8.6 ms) and {sup 12}N(I{sup {pi}}=1{sup +}, T{sub 1/2}=11.0 ms) implanted into polycrystalline Pt(fcc) by means of {beta}-NMR technique for the systematic study of the electric structures of interstitial impurities. (J.P.N.)

  18. Electrophysical properties of PMN-PT-PS-PFN:Li ceramics

    R. Skulski

    2013-01-01

    Full Text Available We present the technology of obtaining and the electrophysical properties of a multicomponent material 0.61PMN-0.20PT-0.09PS-0.1PFN:Li (PMN-PT-PS-PFN:Li. The addition of PFN into PMN-PT decreases the temperature of final sintering which is very important during technological process (addition of Li decreases electric conductivity of PFN. Addition of PS i.e., PbSnO3 (which is unstable in ceramic form permits to shift the temperature of the maximum of dielectric permittivity. One-step method of obtaining ceramic samples from oxides and carbonates has been used. XRD, microstructure, scanning calorimetry measurements and the main dielectric, ferroelectric and electromechanical properties have been investigated for the obtained samples.

  19. The high-pressure phase of CePtAl

    Heymann, Gunter; Heying, Birgit; Rodewald, Ute C.; Janka, Oliver; Univ. Oldenburg

    2017-01-01

    The intermetallic aluminum compound HP-CePtAl was synthesized by arc melting of the elements with subsequent high-pressure/high-temperature treatment at 1620 K and 10.5 GPa in a multianvil press. The compound crystallizes in the hexagonal MgZn_2-type structure (P6_3/mmc) with lattice parameters of a=552.7(1) and c=898.8(2) pm refined from powder X-ray diffraction data. With the help of single crystal investigations (wR=0.0527, 187 F"2 values, 13 variables), the proposed structure type was confirmed and the mixed Pt/Al site occupations could be refined. Magnetic susceptibility measurements showed a disappearance of the complex magnetic ordering phenomena, which are observed in NP-CePtAl.

  20. The high-pressure phase of CePtAl

    Heymann, Gunter [Univ. Innsbruck (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Heying, Birgit; Rodewald, Ute C. [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Univ. Oldenburg (Germany). Inst. fuer Chemie

    2017-03-01

    The intermetallic aluminum compound HP-CePtAl was synthesized by arc melting of the elements with subsequent high-pressure/high-temperature treatment at 1620 K and 10.5 GPa in a multianvil press. The compound crystallizes in the hexagonal MgZn{sub 2}-type structure (P6{sub 3}/mmc) with lattice parameters of a=552.7(1) and c=898.8(2) pm refined from powder X-ray diffraction data. With the help of single crystal investigations (wR=0.0527, 187 F{sup 2} values, 13 variables), the proposed structure type was confirmed and the mixed Pt/Al site occupations could be refined. Magnetic susceptibility measurements showed a disappearance of the complex magnetic ordering phenomena, which are observed in NP-CePtAl.

  1. ANALISIS KINERJA KEUANGAN PADA PT PERKEBUNAN NUSANTARA XIV MAKASSAR

    Jefri Dominggus Simon

    2017-08-01

    Full Text Available JEFRI DOMINGGUS SIMON.2017. Thesis.4513012048. "Financial Performance Analysis at PT Perkebunan Nusantara XIV Makassar". (Mentored by Dr.Miah Said, SE., M.Si as consultant I and Muh.Kafrawi Yunus, SE., MM as consultant II. This study aims to analyze the financial performance of PT Perkebunan Nusantara XIV Makassar during 2013 until 2015 by using ratio analysis: Liquidity, solvency, Activity and Profitability. The results of this study indicate that based on Liquidity ratios including Current ratio, Quick ratio and Cash ratio has increased. In general, the ratio of Solvency is in a less good position, while for Profitability ratio of receivables turnover, inventory turnover and asset turnover fluctuated. In general, the activity ratio of PT Perkebunan Nusantara XIV Makassar in the period of 2013 to 2015 has decreased

  2. Analisa dan Perancangan Jaringan Berbasis VPN Pada PT. Finroll

    Johan Muliadi Kerta

    2010-12-01

    Full Text Available Along with the development of the company to run operations such as data communication and perform other transactions to relations and vice versa, PT Finroll just uses the public network such as sending email to their partners. Data information is not safe in public because it can be tapped or intercepted by unauthorized person. With the Virtual Private Network (VPN, PT Finroll can do business in secure environment to their partners. The methodologies used in this research are data collection that was started by surveying, interviewing, and analyzing the current network topology, performance and design requirements that support network design. From these results, PT Finroll can increase productivity and performance from competition in their business. In addition, with this research company has a better ability to increase their competitiveness in present and the future. 

  3. Audit Sistem Informasi Akuntansi Siklus Pengeluaran pada PT. Lagio Furniture

    Aries Wicaksono

    2014-11-01

    Full Text Available Rapid technological developments make the whole thing easier. Many companies also take advantage of these technological developments. Similarly, the corporate accounting system that uses the benefits of information technology in the form of Accounting Information Systems (AIS. PT. Lagio Furniture is amanufacturing company that produces furniture for the premium class. Information system is an important part that helps the company's operations become more effective and efficient, therefore it is important for information systems running properly.This research aimed to audit the general control and applications control on the expenditure cycle accounting information system at PT. Lagio Furniture. This type of audit is audit around the computer. And then also collecting data through observation and interviews with relevant parties. Results of thereserarch is the expenditure cycle accounting information system at PT. Lagio Furniture was good. But there is still need to be improved in the control plan security, operational management control, and control inputs.

  4. EXAFS Characterization of Dendrimer-Derived Pt/γ-Al2O3

    Siani, A.; Alexeev, O. S.; Williams, C. T.; Ploehn, H. J.; Amiridis, M. D.

    2007-01-01

    The various steps involved in the preparation of a Pt/γ-Al2O3 material using hydroxyl-terminated generation four (G4OH) PAMAM dendrimers as templates were monitored by EXAFS. The results indicate that Cl ligands in the Pt precursors (H2PtCl6 and K2PtCl4) were partially replaced by aquo ligands upon hydrolysis to form [PtCl3(H2O)3]+ and [PtCl2(H2O)2] species. After interaction of such species with G4OH, Cl ligands from the first coordination shell of Pt were further replaced by nitrogen atoms from the dendrimer interior, indicating the complexation of Pt with the dendrimer. This process was accompanied by a transfer of the electron density from the dendrimer to Pt, indicating that the former plays the role of a ligand. Following treatment of the H2PtCl6/G4OH and K2PtCl4/G4OH composites with NaBH4, no substantial changes were detecteded in the electronic or coordination environment of Pt, and no formation of metal nanoparticles was observed. However, when the reduction treatment was performed with H2, the formation of extremely small Pt clusters incorporating no more than 4 Pt atoms was observed. These Pt species remained strongly bonded to the dendrimer and their nuclearity depends on the length of the H2 treatment. Formation of Pt nanoparticles with an average diameter of approximately 10 A was finally observed after the deposition of H2PtCl6/G4OH on γ-Al2O3 and drying, suggesting that their formation may be related to the collapse of the dendrimer structure. The Pt nanoparticles formed appear to have high mobility, since subsequent thermal treatment in O2/H2 led to further sintering

  5. Pt/AlPO{sub 4} nanocomposite thin-film electrodes for ethanol electrooxidation

    Oh, Yuhong; Kang, Joonhyeon; Nam, Seunghoon; Byun, Sujin [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of); Park, Byungwoo, E-mail: byungwoo@snu.ac.kr [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2012-07-16

    The enhanced catalytic properties toward ethanol electrooxidation on Pt/AlPO{sub 4} nanocomposite thin-film electrodes were investigated. The Pt/AlPO{sub 4} nanocomposites with various Al/Pt ratios (0.27, 0.57, and 0.96) were fabricated by a co-sputtering method. All of the Pt/AlPO{sub 4} nanocomposites showed a negative shift in the onset potential and a higher current density than those of pure Pt electrode for the electrooxidation of ethanol. Among the various Pt/AlPO{sub 4} nanocomposite thin-film electrodes, the electrode with an atomic ratio of Al to Pt of 0.57 showed the highest electrocatalytic activity for ethanol electrooxidation. The activation enthalpy for the optimum Pt/AlPO{sub 4} nanocomposite was approximately 0.05 eV lower than that of pure Pt. It is believed that the enhancement in catalytic activity is due to the electron-rich Pt resulting from the Fermi-energy difference between Pt and AlPO{sub 4}. - Highlights: Black-Right-Pointing-Pointer The enhanced ethanol electrooxidation on Pt/AlPO{sub 4} nanocomposites is investigated. Black-Right-Pointing-Pointer The Pt/AlPO{sub 4} exhibits higher current density and lower onset potential than pure Pt. Black-Right-Pointing-Pointer The activation enthalpy for optimum Pt/AlPO{sub 4} electrode is {approx}0.05 eV lower than pure Pt. Black-Right-Pointing-Pointer XPS shows electron-rich Pt due to Fermi-energy difference between Pt and AlPO{sub 4}.

  6. Ternary Pt-Ru-Ni catalytic layers for methanol electrooxidation prepared by electrodeposition and galvanic replacement

    Athanasios ePapaderakis

    2014-06-01

    Full Text Available Ternary Pt-Ru-Ni deposits on glassy carbon substrates, Pt-Ru(Ni/GC, have been formed by initial electrodeposition of Ni layers onto glassy carbon electrodes, followed by their partial exchange for Pt and Ru, upon their immersion into equimolar solutions containing complex ions of the precious metals. The overall morphology and composition of the deposits has been studied by SEM microscopy and EDS spectroscopy. Continuous but nodular films have been confirmed, with a Pt÷Ru÷Ni % bulk atomic composition ratio of 37÷12÷51 (and for binary Pt-Ni control systems of 47÷53. Fine topographical details as well as film thickness have been directly recorded using AFM microscopy. The composition of the outer layers as well as the interactions of the three metals present have been studied by XPS spectroscopy and a Pt÷Ru÷Ni % surface atomic composition ratio of 61÷12÷27 (and for binary Pt-Ni control systems of 85÷15 has been found, indicating the enrichment of the outer layers in Pt; a shift of the Pt binding energy peaks to higher values was only observed in the presence of Ru and points to an electronic effect of Ru on Pt. The surface electrochemistry of the thus prepared Pt-Ru(Ni/GC and Pt(Ni/GC electrodes in deaerated acid solutions (studied by cyclic voltammetry proves the existence of a shell consisting exclusively of Pt-Ru or Pt. The activity of the Pt-Ru(Ni deposits towards methanol oxidation (studied by slow potential sweep voltammetry is higher from that of the Pt(Ni deposit and of pure Pt; this enhancement is attributed both to the well-known Ru synergistic effect due to the presence of its oxides but also (based on the XPS findings to a modification effect of Pt electronic properties.

  7. Mechanical properties of non-centrosymmetric CePt3Si and CePt3B

    Rogl, G.; Legut, D.; Sýkora, R.; Müller, P.; Müller, H.; Bauer, E.; Puchegger, S.; Zehetbauer, M.; Rogl, P.

    2017-05-01

    Elastic moduli, hardness (both at room temperature) and thermal expansion (4.2-670 K) have been experimentally determined for polycrystalline CePt3Si and its prototype compound CePt3B as well as for single-crystalline CePt3Si. Resonant ultrasound spectroscopy was used to determine elastic properties (Young’s modulus E and Poisson’s ratio ν) via the eigenfrequencies of the sample and the knowledge of sample mass and dimensions. Bulk and shear moduli were calculated from E and ν, and the respective Debye temperatures were derived. In addition, ab initio DFT calculations were carried out for both compounds. A comparison of parameters evaluated from DFT with those of experiments revealed, in general, satisfactory agreement. Positive and negative thermal expansion values obtained from CePt3Si single crystal data are fairly well explained in terms of the crystalline electric field model, using CEF parameters derived recently from inelastic neutron scattering. DFT calculations, in addition, demonstrate that the atomic vibrations keep almost unaffected by the antisymmetric spin-orbit coupling present in systems with crystal structures having no inversion symmetry. This is opposite to electronic properties, where the antisymmetric spin-orbit interaction has shown to distinctly influence features like the superconducting condensate of CePt3Si.

  8. Spontaneous deposition of Ru on Pt (100: morphological and electrochemical studies. Preliminary results of ethanol oxidation at Pt(100/Ru

    Colle Vinicius D.

    2003-01-01

    Full Text Available In the present work ruthenium was deposited in submonolayer amounts on Pt(100 by spontaneous deposition at several deposition times. The Pt (100/Ru surfaces were analyzed using ex-situ STM to image the deposits characteristic of ruthenium on Pt (100. It was observed the formation of ruthenium islands with diameters between 1.0 and 4.5 nm with bi-atomic thickness in the center of the islands. A homogeneous distribution of the ruthenium islands on the platinum terraces was found, with no preferential deposition on steps or surface defect sites. The ruthenium coverage degree had been calculated by the decrease of charge of the hydrogen adsorption-desorption peaks in the cyclic voltammograms of the Pt(100/Ru electrodes. The Pt(100/Ru electrodes with a ruthenium coverage degree of ca. 0.3 showed a high activity for the ethanol electrooxidation. The electrochemical experimental results support strongly the bifunctional mechanism for the enhanced ethanol oxidation.

  9. Electron density in non-ideal metal complexes. Pt. 1

    Varghese, J.N.; Maslen, E.N.

    1985-01-01

    The structure of copper sulphate pentahydrate was refined using an accurate set of X-ray data: Msub(r)=249.68, triclinic, Panti 1, a=6.1224(4), b=10.7223(4), c=5.9681(4) A, α=82.35(2), β=107.33(2), γ=102.60(4) 0 , V=364.02(3) A 3 , Z=2, Dsub(x)=2.278 Mg m -3 , Mo Kα, lambda=0.71069 A, μ=3.419 mm -1 , F(000)=254.0, T=298 K, R=0.039 for 7667 reflections. The structural parameters are compared with those obtained by neutron diffraction. The differences between X-ray and neutron positions are related to the hydrogen bonding in the structure. The dominant features in the residual density near the two crystallographically independent Cu atoms result from the redistribution of 3d electrons due to bonding. The density is anisotropic, as expected in view of the Jahn-Teller distortion in the structure. Marked differences in the d-electron distributions for the two Cu atoms correlate with small variations in molecular geometry. Second-nearest-neighbour effects, such as those arising from differently oriented ligating waters, are significant in this structure. Sharp features in the difference density close to the Cu nuclei are similar to those in other Cu 2+ complexes, indicating that the electron density in this region is more reliable than previously believed. (orig.)

  10. 9 CFR 311.39 - Biological residues.

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Biological residues. 311.39 Section... Biological residues. Carcasses, organs, or other parts of carcasses of livestock shall be condemned if it is determined that they are adulterated because of the presence of any biological residues. ...

  11. Cycling of grain legume residue nitrogen

    Jensen, E.S.

    1995-01-01

    Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

  12. Neutron residual stress measurements in linepipe

    Law, Michael; Gnaepel-Herold, Thomas; Luzin, Vladimir; Bowie, Graham

    2006-01-01

    Residual stresses in gas pipelines are generated by manufacturing and construction processes and may affect the subsequent pipe integrity. In the present work, the residual stresses in eight samples of linepipe were measured by neutron diffraction. Residual stresses changed with some coating processes. This has special implications in understanding and mitigating stress corrosion cracking, a major safety and economic problem in some gas pipelines

  13. Oxygen reduction reaction on a highly-alloyed Pt-Ni supported carbon electrocatalyst in acid solution

    Zheng, H

    2010-08-31

    Full Text Available Alloyed electrocatalysts such as PtNi/C[1-2], PtCo/C[3], PtCr/C[4], PtFe/C [5-6], and non-alloyed Pt-TiO2/C were reportedly investigated for methanol tolerance during Oxygen reduction reaction (ORR). The high methanol tolerance...

  14. Temperature effect on the electrode kinetics of ethanol oxidation on Pd modified Pt electrodes and the estimation of intermediates formed in alkali medium

    Mahapatra, S.S.; Dutta, A. [Department of Chemistry, Bengal Engineering and Science University, PO-B. Garden, Shibpur, Howrah 711 103, West Bengal (India); Datta, J., E-mail: jayati_datta@rediffmail.co [Department of Chemistry, Bengal Engineering and Science University, PO-B. Garden, Shibpur, Howrah 711 103, West Bengal (India)

    2010-12-01

    Ethanol has been recognized as the ideal fuel for direct alcohol fuel cell (DAFC) systems due to its high energy density, non-toxicity and its bio-generation. However the complete conversion of ethanol to CO{sub 2} is still met with challenges, due to dearth of suitable catalysts for the electro-oxidation. In the present work the effect of temperature on the catalytic oxidation of ethanol in alkaline medium over electrodeposited Pt and Pt-Pd alloyed nano particles on carbon support and also on the product formation during the course of reaction have been studied within the temperature range of 20-80 {sup o}C. The information on surface morphology, structural characteristics and bulk composition of the catalyst was obtained using SEM, XRD and EDX. BET surface area and pore widths of the catalyst particles were calculated by applying the BET equation to the adsorption isotherms. The electrochemical techniques like cyclic voltammetry, chronoamperometry and impedance spectroscopy were employed to investigate the electrochemical parameters related to electro-oxidation of ethanol in alkaline pH on the catalyst surfaces under the influence of temperature. The results show that the oxidation kinetics of ethanol on the alloyed Pt-Pd/C catalysts is significantly improved compared to that on Pt alone. The observations were interpreted in terms of the synergistic effect of higher electrochemical surface area, preferred OH{sup -} adsorption on the surface and the ad-atom contribution of the alloyed matrix. A pronounced influence of temperature on the reaction kinetics was manifested in the diminution of charge transfer resistance and activation energy of the ethanol oxidation with Pd incorporation into the Pt matrix, ensuring greater tolerance of the alloyed catalyst towards ethanolic residues. The higher yield of the reaction products like acetate and CO{sub 3}{sup -2} on the alloyed catalyst compared to Pt alone in alkaline medium, as estimated by ion chromatography, further

  15. Direct methanol fuel cell with extended reaction zone anode: PtRu and PtRuMo supported on graphite felt

    Bauer, Alex; Gyenge, Előd L.; Oloman, Colin W.

    Pressed graphite felt (thickness ∼350 μm) with electrodeposited PtRu (43 g m -2, 1.4:1 atomic ratio) or PtRuMo (52 g m -2, 1:1:0.3 atomic ratio) nanoparticle catalysts was investigated as an anode for direct methanol fuel cells. At temperatures above 333 K the fuel cell performance of the PtRuMo catalyst was superior compared to PtRu. The power density was 2200 W m -2 with PtRuMo at 5500 A m -2 and 353 K while under the same conditions PtRu yielded 1925 W m -2. However, the degradation rate of the Mo containing catalyst formulation was higher. Compared to conventional gas diffusion electrodes with comparable PtRu catalyst composition and load, the graphite felt anodes gave higher power densities mainly due to the extended reaction zone for methanol oxidation.

  16. Binuclear Pt-Tl bonded complex with square pyramidal coordination around Pt: a combined multinuclear NMR, EXAFS, UV-Vis, and DFT/TDDFT study in dimethylsulfoxide solution.

    Purgel, Mihály; Maliarik, Mikhail; Glaser, Julius; Platas-Iglesias, Carlos; Persson, Ingmar; Tóth, Imre

    2011-07-04

    The structure and bonding of a new Pt-Tl bonded complex formed in dimethylsulfoxide (dmso), (CN)(4)Pt-Tl(dmso)(5)(+), have been studied by multinuclear NMR and UV-vis spectroscopies, and EXAFS measurements in combination with density functional theory (DFT) and time dependent density functional theory (TDDFT) calculations. This complex is formed following the equilibrium reaction Pt(CN)(4)(2-) + Tl(dmso)(6)(3+) ⇆ (CN)(4)Pt-Tl(dmso)(5)(+) + dmso. The stability constant of the Pt-Tl bonded species, as determined using (13)C NMR spectroscopy, amounts to log K = 2.9 ± 0.2. The (NC)(4)Pt-Tl(dmso)(5)(+) species constitutes the first example of a Pt-Tl bonded cyanide complex in which the sixth coordination position around Pt (in trans with respect to the Tl atom) is not occupied. The spectral parameters confirm the formation of the metal-metal bond, but differ substantially from those measured earlier in aqueous solution for complexes (CN)(5)Pt-Tl(CN)(n)(H(2)O)(x)(n-) (n = 0-3). The (205) Tl NMR chemical shift, δ = 75 ppm, is at extraordinary high field, while spin-spin coupling constant, (1)J(Pt-Tl) = 93 kHz, is the largest measured to date for a Pt-Tl bond in the absence of supporting bridging ligands. The absorption spectrum is dominated by two strong absorption bands in the UV region that are assigned to MMCT (Pt → Tl) and LMCT (dmso → Tl) bands, respectively, on the basis of MO and TDDFT calculations. The solution of the complex has a bright yellow color as a result of a shoulder present on the low energy side of the band at 355 nm. The geometry of the (CN)(4)Pt-Tl core can be elucidated from NMR data, but the particular stoichiometry and structure involving the dmso ligands are established by using Tl and Pt L(III)-edge EXAFS measurements. The Pt-Tl bond distance is 2.67(1) Å, the Tl-O bond distance is 2.282(6) Å, and the Pt-C-N entity is linear with Pt-C and Pt···N distances amounting to 1.969(6) and 3.096(6) Å, respectively. Geometry optimizations on

  17. MCNP4A: Features and philosophy

    Hendricks, J.S.

    1993-01-01

    This paper describes MCNP, states its philosophy, introduces a number of new features becoming available with version MCNP4A, and answers a number of questions asked by participants in the workshop. MCNP is a general-purpose three-dimensional neutron, photon and electron transport code. Its philosophy is ''Quality, Value and New Features.'' Quality is exemplified by new software quality assurance practices and a program of benchmarking against experiments. Value includes a strong emphasis on documentation and code portability. New features are the third priority. MCNP4A is now available at Los Alamos. New features in MCNP4A include enhanced statistical analysis, distributed processor multitasking, new photon libraries, ENDF/B-VI capabilities, X-Windows graphics, dynamic memory allocation, expanded criticality output, periodic boundaries, plotting of particle tracks via SABRINA, and many other improvements. 23 refs

  18. High-coercivity FePt sputtered films

    Luong, N.H.; Hiep, V.V.; Hong, D.M.; Chau, N.; Linh, N.D.; Kurisu, M.; Anh, D.T.K.; Nakamoto, G.

    2005-01-01

    Fe 56 Pt 44 thin films have been prepared by RF magnetron sputtering on Si substrates. The substrate temperature was kept at 350 deg C. The X-ray diffraction patterns of as-deposited FePt films exhibited a disordered structure. Annealing of the films at 650-685 deg C for 1 h yielded an ordered L1 0 phase with FCT structure. The high value for coercivity H C of 17 kOe was obtained at room temperature for the 68 nm thick film annealed at 685 deg C. The hard magnetic properties as well as grain structure of the films strongly depend on the annealing conditions

  19. Charge transport in a CoPt3 nanocrystal microwire

    Beecher, P.; De Marzi, G.; Quinn, A.J.; Redmond, G.; Shevchenko, E.V.; Weller, H.

    2004-01-01

    The electrical characteristics of single CoPt 3 nanocrystal microwires formed by magnetic field-directed growth from colloidal solutions are presented. The wires comprise disordered assemblies of discrete nanocrystals, separated from each other by protective organic ligand shells. Electrical data indicate that the activated charge transport properties of the wires are determined by the nanocrystal charging energy, governed by the size and capacitance of the individual nanocrystals. Focused ion beam-assisted deposition of Pt metal at the wire-electrode junctions is employed to optimize the wire-electrode contacts, whilst maintaining the nanocrystal-dominated transport characteristics of these one-dimensional nanocrystal structures

  20. CoPt nanoparticles deposited by electron beam evaporation

    Castaldi, L.; Giannakopoulos, K.; Travlos, A.; Niarchos, D.; Boukari, S.; Beaurepaire, E.

    2005-01-01

    Co 50 Pt 50 nanoparticles were co-deposited on thermally oxidized Si substrates by electron beam evaporation at 750 deg C. The mean particle sizes are between ∼5 and ∼20 nm and depend on the nominal thickness of the layer. Different processing conditions resulted in different structural and morphological properties of the samples which led to superparamagnetic and ferromagnetic behaviors. The post-annealing treatment of the CoPt nanograins resulted in the crystallization of the L1 0 ordered phase and in the magnetic hardening of nanoparticles with a maximum coercivity of ∼7.4 kOe

  1. Low $p_T$ Hadronic Physics with CMS

    AUTHOR|(CDS)2072044

    2007-01-01

    The pixel detector of CMS can be used to reconstruct very low pT charged particles down to about 0.1 GeV/c. This can be achieved with good efficiency, resolution and negligible fake rate for elementary collisions. In case of central PbPb the fake rate can be kept low for pT>0.4 GeV/c. In addition, the detector can be employed for identification of neutral hadrons (V0s) and converted photons.

  2. Low pT Hadronic Physics with CMS

    Sikler, Ferenc

    2007-01-01

    The pixel detector of CMS can be used to reconstruct very low pT charged particles down to about 0.1 GeV/c. This can be achieved with good efficiency, resolution and negligible fake rate for elementary collisions. In case of central PbPb the fake rate can be kept low for pT>0.4 GeV/c. In addition, the detector can be employed for identification of neutral hadrons (V0s) and converted photons.

  3. Pengelolaan Media Sosial Oleh Unit Corporate Communication PT GMF Aeroasia

    Fajar Syuderajat

    2017-01-01

    Studi ini berjudul:  Pengelolaan  Media  Sosial  oleh  Unit Corporate Communication PT GMF AeroAsia. Seiring dengan meningkatknya jumlah pengguna social media telah melahirkan media baru bagi bidang komunikasi khususnya dunia public relations. Kesempatan ini kemudian dimanfaatkan oleh PT GMF AeroAsia untuk memanfaatkan media sosial yang dijadikan sebagai media komunikasi dengan memberikan  informasi  seputar  dunia  aviasi  dan  bidang  MRO  (maintenance, repair,  organization)  PT  GMF AeroA...

  4. Functionalized graphene-Pt composites for fuel cells and photoelectrochemical cells

    Diankov, Georgi; An, Jihwan; Park, Joonsuk; Goldhaber, David J. K.; Prinz, Friedrich B.

    2017-08-29

    A method of growing crystals on two-dimensional layered material is provided that includes reversibly hydrogenating a two-dimensional layered material, using a controlled radio-frequency hydrogen plasma, depositing Pt atoms on the reversibly hydrogenated two-dimensional layered material, using Atomic Layer Deposition (ALD), where the reversibly hydrogenated two-dimensional layered material promotes loss of methyl groups in an ALD Pt precursor, and forming Pt-O on the reversibly hydrogenated two-dimensional layered material, using combustion by O.sub.2, where the Pt-O is used for subsequent Pt half-cycles of the ALD process, where growth of Pt crystals occurs.

  5. Preparation of Stable Pt-Clay Nanocatalysts for Self-humidifying Proton Exchange Membrane Fuel Cells

    Zhang, Wenjing

    and complexity of the whole system. Therefore, we have designed a novel Pt-clay nanocatalyst and developed a Pt-clay/Nafion nanocomposite membrane to significantly enhanced proton conductivity without any external humidification. In this study, monolayer of Pt nanoparticles of diameters of 2-3 nm with a high...... crystallinity were successfully anchored onto exfoliated nanoclay surfaces using a novel chemical vapor deposition process. Chemical bonding of Pt to the oxygen on the clay surface ensured the stability of the Pt nanoparticles, and hence, no leaching of Pt particles was observed after a prolonged...

  6. A comparative study of the adsorption and hydrogenation of acrolein on Pt(1 1 1), Ni(1 1 1) film and Pt Ni Pt(1 1 1) bimetallic surfaces

    Murillo, Luis E.; Chen, Jingguang G.

    In this study we have investigated the reaction pathways for the decomposition and hydrogenation of acrolein (CH 2dbnd CH-CH dbnd O) on Ni/Pt(1 1 1) surfaces under ultra-high vacuum (UHV) conditions using temperature programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). While gas-phase hydrogenation products are not observed from clean Pt(1 1 1), the subsurface Pt-Ni-Pt(1 1 1), with Ni residing below the first layer of Pt, is active for the self-hydrogenation of the C dbnd O bond to produce unsaturated alcohol (2-propenol) and the C dbnd C bond to produce saturated aldehyde (propanal), with the latter being the main hydrogenation product without the consecutive hydrogenation to saturated alcohol. For a thick Ni(1 1 1) film prepared on Pt(1 1 1), the self-hydrogenation yields for both products are lower than that from the Pt-Ni-Pt(1 1 1) surface. The presence of pre-adsorbed hydrogen further enhances the selectivity toward C dbnd O bond hydrogenation on the Pt-Ni-Pt(1 1 1) surface. In addition, HREELS studies of the adsorption of the two hydrogenation products, 2-propenol and propanal, are performed on the Pt-Ni-Pt(1 1 1) surface to identify the possible surface intermediates during the reaction of acrolein. The results presented here indicate that the hydrogenation activity and selectivity of acrolein on Pt(1 1 1) can be significantly modified by the formation of the bimetallic surfaces.

  7. Natural radioactivity in petroleum residues

    Gazineu, M.H.P.; Gazineu, M.H.P.; Hazin, C.A.; Hazin, C.A.

    2006-01-01

    The oil extraction and production industry generates several types of solid and liquid wastes. Scales, sludge and water are typical residues that can be found in such facilities and that can be contaminated with Naturally Occurring Radioactive Material (N.O.R.M.). As a result of oil processing, the natural radionuclides can be concentrated in such residues, forming the so called Technologically Enhanced Naturally Occurring Radioactive Material, or T.E.N.O.R.M.. Most of the radionuclides that appear in oil and gas streams belong to the 238 U and 232 Th natural series, besides 40 K. The present work was developed to determine the radionuclide content of scales and sludge generated during oil extraction and production operations. Emphasis was given to the quantification of 226 Ra, 228 Ra and 40 K since these radionuclides,are responsible for most of the external exposure in such facilities. Samples were taken from the P.E.T.R.O.B.R.A.S. unity in the State of Sergipe, in Northeastern Brazil. They were collected directly from the inner surface of water pipes and storage tanks, or from barrels stored in the waste storage area of the E and P unit. The activity concentrations for 226 Ra, 228 Ra and 40 K were determined by using an HP Ge gamma spectrometric system. The results showed concentrations ranging from 42.7 to 2,110.0 kBq/kg for 226 Ra, 40.5 to 1,550.0 kBq/kg for 228 Ra, and 20.6 to 186.6 kBq/kg for 40 K. The results highlight the importance of determining the activity concentration of those radionuclides in oil residues before deciding whether they should be stored or discarded to the environment. (authors)

  8. On the Relationship of Magnetocrystalline Anisotropy and Stoichiometry in Epitaxial L1{sub 0} CoPt(001) and FePt(001) Thin Films

    Barmak, K

    2004-08-10

    Two series of epitaxial CoPt and FePt films, with nominal thicknesses of 42 or 50 nm, were prepared by sputtering onto single crystal MgO(001) substrates in order to investigate the chemical ordering and the resultant magnetic properties as a function of alloy composition. In the first series, the film composition was kept constant, while the substrate temperature was increased from 144 to 704 C. In the second series the substrate temperature was kept constant at 704 C for CoPt and 620 C for FePt, while the alloy stoichiometry was varied in the nominalrange of 40-60 at% Co(Fe). Film compositions and thicknesses were measured via Rutherford backscattering spectrometry. The lattice and long-range order parameter for the L1{sub 0} phase were obtained for both sets of films using x-ray diffraction. The room-temperature magnetocrystalline anisotropy constants were determined for a subset of the films using torque magnetometry. The order parameter was found to increase with increasing temperature, with ordering occurring more readily in FePt when compared with CoPt. A perpendicular anisotropy developed in CoPt for substrate temperatures above 534 C and in FePt above 321 C. The structure and width of the magnetic domains in CoPt and FePt, as seen by magnetic force microscopy, also demonstrated an increase in magnetic anisotropy with increasing temperature. For the films deposited at the highest temperatures (704 C for CoPt and 620 C for FePt), the order parameter reached a maximum near the equiatomic composition, whereas the magnetocrystalline anisotropy increased as the concentration of Co or Fe was increased from below to slightly above the equiatomic composition. It is concluded that non-stoichiometric L1{sub 0} CoPt and FePt, with a slight excess of Co or Fe, are preferable for applications requiring the highest anisotropies.

  9. The controlled formation and cleavage of an intramolecular d8-d8 Pt-Pt interaction in a dinuclear cycloplatinated molecular "pivot-hinge".

    Koo, Chi-Kin; Wong, Ka-Leung; Lau, Kai-Cheung; Wong, Wai-Yeung; Lam, Michael Hon-Wah

    2009-08-03

    The bis(diphenylphosphino)methane (dppm)-bridged dinuclear cycloplatinated complex {[Pt(L)](2)(mu-dppm)}(2+) (Pt(2)dppm; HL: 2-phenyl-6-(1H-pyrazol-3-yl)-pyridine) demonstrates interesting reversible "pivot-hinge"-like intramolecular motions in response to the protonation/deprotonation of L. In its protonated "closed" configuration, the two platinum(II) centers are held in position by intramolecular d(8)-d(8) Pt-Pt interaction. In its deprotonated "open" configuration, such Pt-Pt interaction is cleaved. To further understand the mechanism behind this hingelike motion, an analogous dinuclear cycloplatinated complex, {[Pt(L)](2)(mu-dchpm)}(2+) (Pt(2)dchpm) with bis(dicyclohexylphosphino)methane (dchpm) as the bridging ligand, was synthesized. From its protonation/deprotonation responses, it was revealed that aromatic pi-pi interactions between the phenyl moieties of the mu-dppm and the deprotonated pyrazolyl rings of L was essential to the reversible cleavage of the intramolecular Pt-Pt interaction in Pt(2)dppm. In the case of Pt(2)dchpm, spectroscopic and spectrofluorometric titrations as well as X-ray crystallography indicated that the distance between the two platinum(II) centers shrank upon deprotonation, thus causing a redshift in its room-temperature triplet metal-metal-to-ligand charge-transfer emission from 614 to 625 nm. Ab initio calculations revealed the presence of intramolecular hydrogen bonding between the deprotonated and negatively charged 1-pyrazolyl-N moiety and the methylene CH and phenyl C-H of the mu-dppm. The "open" configuration of the deprotonated Pt(2)dppm was estimated to be 19 kcal mol(-1) more stable than its alternative "closed" configuration. On the other hand, the open configuration of the deprotonated Pt(2)dchpm was 6 kcal mol(-1) less stable than its alternative closed configuration.

  10. Residual Liquefaction under Standing Waves

    Kirca, V.S. Ozgur; Sumer, B. Mutlu; Fredsøe, Jørgen

    2012-01-01

    This paper summarizes the results of an experimental study which deals with the residual liquefaction of seabed under standing waves. It is shown that the seabed liquefaction under standing waves, although qualitatively similar, exhibits features different from that caused by progressive waves....... The experimental results show that the buildup of pore-water pressure and the resulting liquefaction first starts at the nodal section and spreads towards the antinodal section. The number of waves to cause liquefaction at the nodal section appears to be equal to that experienced in progressive waves for the same...

  11. Process to recycle shredder residue

    Jody, Bassam J.; Daniels, Edward J.; Bonsignore, Patrick V.

    2001-01-01

    A system and process for recycling shredder residue, in which separating any polyurethane foam materials are first separated. Then separate a fines fraction of less than about 1/4 inch leaving a plastics-rich fraction. Thereafter, the plastics rich fraction is sequentially contacted with a series of solvents beginning with one or more of hexane or an alcohol to remove automotive fluids; acetone to remove ABS; one or more of EDC, THF or a ketone having a boiling point of not greater than about 125.degree. C. to remove PVC; and one or more of xylene or toluene to remove polypropylene and polyethylene. The solvents are recovered and recycled.

  12. Lifetimes of excited states in 196198Pt; application of interacting bason approximation model to even Pt isotopes systematics

    Bolotin, H.H.; Stuchbery, A.E.; Morrison, I.; Kennedy, D.L.; Ryan, C.G.; Sie, S.H.

    1981-01-01

    The lifetimes and lifetime limits of the low-lying excited states up to and including the 6 1 + levels in 196 198 Pt were determined by the rcoil-distance method (RDM). Gamma-ray angular distributions in 198 Pt were also measured. These states were populated by multiple Coulomb excitation using 220-MeV 58 Ni ion beams and the measurements carried out in coincidence with backscattered projectiles. The measured mean lives of the states and B(E2) values inferred for the transitions between levels are presented. These specific findings, and the observed structure systematics obtained from the combination of the present results and those of prior workers for the even 194 - 198 Pt isotopes, are critically compared with our structure calculations employing the Interacting Boson Approximation (IBA) model incorporating a symmetry-breaking quadrupole force. Evaluative comparisons are also made with Boson Expansion Theory (BET) calculations

  13. Lifetimes of excited states in 196, 198Pt; Application of interacting boson approximation model to even Pt isotopes systematics

    Bolotin, H. H.; Stuchbery, A. E.; Morrison, I.; Kennedy, D. L.; Ryan, C. G.; Sie, S. H.

    1981-11-01

    The lifetimes and lifetime limits of the low-lying excited states up to and including the 6 1+ levels in 196, 198Pt were determined by the recoil-distance method (RDM). Gamma-ray angular distributions in 198Pt were also measured. These states were populated by multiple Coulomb excitation using 220 MeV 58Ni ion beams and the measurements were carried out in coincidence with back-scattered projectiles. The measured mean lives of the states and B(E2) values inferred for the transitions between levels are presented. These specific findings, and the observed structure systematics obtained from the combination of the present results and those of prior workers for the even 194-198Pt isotopes, are critically compared with our structure calculations employing the interacting boson approximation (IBA) model incorporating a symmetry-breaking quadrupole force; evaluative comparisons are also made with boson expansion theory (BET) calculations.

  14. Lifetimes of excited states in 196,198Pt; application of interacting boson approximation model to even Pt isotopes systematics

    Bolotin, H.H.; Stuchbery, A.E.; Morrison, I.; Kennedy, D.L.; Ryan, C.G.; Sie, S.H.

    1981-01-01

    The lifetimes and lifetime limits of the low-lying excited states up to and including the 6 + 1 levels in sup(196, 198)Pt were determined by the recoil-distance method (RDM). Gamma-ray angular distributions in 198 Pt were also measured. These states were populated by multiple Coulomb excitation using 220 MeV 58 Ni ion beams and the measurements were carried out in coincidence with backscattering projectiles. The measured mean lives of the states and B(E2) values inferred for the transitions between levels are presented. These specific findings, and the observed structure systematics obtained from the combination of the present results and those of prior workers for the even sup(194-198)Pt isotopes, are critically compared with our structure calculations employing the interacting boson approximation (IBA) model incorporating a symmetry-breaking quadrupole force; evaluative comparisons are also made with boson expansion theory (BET) calculations. (orig.)

  15. Synthesis and characterization of Pd-on-Pt and Au-on-Pt bimetallic nanosheaths on multiwalled carbon nanotubes

    Wang Shuangyin; Jiang, San Ping; Wang Xin

    2011-01-01

    The authors have successfully synthesized Pd-on-Pt (thickness: 12 nm) and Au-on-Pt bimetallic nanosheaths on multiwalled carbon nanotubes (MWCNTs) via a seed-mediated growth approach. Pt nanoparticles as seeds were pre-deposited on MWCNTs with uniform distribution followed by the successive seed-mediated growth of metal atoms reduced by a weak reducing agent, ascorbic acid. The essential role of pre-deposited nanoseed particles on MWCNTs was demonstrated. The as-prepared materials were characterization by transition electron microscopy, energy-dispersive X-ray spectroscopy, and element mapping tools. The current strategy extends the classical seed-mediated growth method to prepare bimetallic nanosheath on MWCNT support.

  16. Single-Crystalline cooperite (PtS): Crystal-Chemical characterization, ESR spectroscopy, and {sup 195}Pt NMR spectroscopy

    Rozhdestvina, V. I., E-mail: veronika@ascnet.ru; Ivanov, A. V.; Zaremba, M. A. [Far East Division, Russian Academy of Sciences, Institute of Geology and Nature Management (Russian Federation); Antsutkin, O. N.; Forsling, W. [Lulea University of Technology (Sweden)

    2008-05-15

    Single-crystalline cooperite (PtS) with a nearly stoichiometric composition was characterized in detail by X-ray diffraction, electron-probe X-ray microanalysis, and high-resolution scanning electron microscopy. For the first time it was demonstrated that {sup 195}Pt static and MAS NMR spectroscopy can be used for studying natural platinum minerals. The {sup 195}Pt chemical-shift tensor of cooperite was found to be consistent with the axial symmetry and is characterized by the following principal values: {delta}{sub xx} = -5920 ppm, {delta}{sub yy} = -3734 ppm, {delta}{sub zz} = +4023 ppm, and {delta}{sub iso} = -1850 ppm. According to the ESR data, the samples of cooperite contain copper(II), which is adsorbed on the surface during the layer-by-layer crystal growth and is not involved in the crystal lattice.

  17. Electrooxidation of ethanol on Pt and PtRu surfaces investigated by ATR surface-enhanced infrared absorption spectroscopy

    Silva, Marcio F.; Camara, Giuseppe A., E-mail: giuseppe.silva@ufms.br [Departamento de Quimica, Universidade Federal do Mato Grosso do Sul, Campo Grande-MS (Brazil); Batista, Bruno C.; Boscheto, Emerson [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos-SP, (Brazil); Varela, Hamilton, E-mail: varela@iqsc.usp.br [Ertl Center for Electrochemistry and Catalysis, Gwangju Institute of Science and Technology (GIST), Gwangju (Korea, Republic of)

    2012-05-15

    Herein, it was investigated for the first time the electro-oxidation of ethanol on Pt and PtRu electrodeposits in acidic media by using in situ surface enhanced infrared absorption spectroscopy with attenuated total reflection (ATR-SEIRAS). The experimental setup circumvents the weak absorbance signals related to adsorbed species, usually observed for rough, electrodeposited surfaces, and allows a full description of the CO coverage with the potential for both catalysts. The dynamics of adsorption-oxidation of CO was accessed by ATR-SEIRAS experiments (involving four ethanol concentrations) and correlated with expressions derived from a simple kinetic model. Kinetic analysis suggests that the growing of the CO adsorbed layer is nor influenced by the presence of Ru neither by the concentration of ethanol. The results suggest that the C-C scission is not related to the presence of Ru and probably happens at Pt sites. (author)

  18. He/Ar-atom scattering from molecular monolayers: C{sub 60}/Pt(111) and graphene/Pt(111)

    Yamada, Y; Sugawara, C; Satake, Y; Yokoyama, Y; Okada, R; Nakayama, T; Sasaki, M [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki (Japan); Kondo, T; Oh, J; Nakamura, J [Institute of Material Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki (Japan); Hayes, W W [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States)

    2010-08-04

    Supersonic He and Ar atomic beam scattering from C{sub 60} and graphene monolayers adsorbed on a Pt(111) surface are demonstrated in order to obtain detailed insight into a gas-molecule collision that has not been studied in detail so far. The effective masses and phonon spectral densities of the monolayers seen by different projectiles are discussed based on classical models such as the hard cube model and the recently developed smooth surface model. Large effective masses are deduced for both the monolayers, suggesting collective effects of surface atoms in the single collision event. The effective Debye temperature of graphene was found to be similar to that reported in highly oriented pyrolytic graphite (HOPG), indicating that the graphene is decoupled well from the Pt substrate. A much smaller Debye-Waller factor was found for the C{sub 60} layer, probably reflecting the strong C{sub 60}-Pt(111) interaction.

  19. Fabrication of CuO–Pt core–shell nanohooks by in situ reconstructing the Pt-shells

    Cao, Fan; Zheng, He; Zhao, Ligong; Huang, Rui; Jia, Shuangfeng; Liu, Huihui; Li, Lei; Wang, Zhao; Hu, Yongming; Gu, Haoshuang; Wang, Jianbo

    2018-05-01

    The design of various nanostructures with specific compositions and shapes is highly demanded due to the widespread use of micro/nano electro-mechanical systems. In this work, one-dimensional CuO–Pt core–shell nanowires (NWs) are acquired by depositing Pt nanoparticles onto CuO NWs and then mechanically-shaped into nanohooks. Subsequently, the hook-like shape is maintained by the Pt-shell which is reconstructed via Joule heat and re-solidified after cooling down, during which the elastic strain energy is stored in the CuO-core. The results provide a simple strategy to design nanostructures with various compositions and shapes, implying the potential applications in mechanical energy storage and shape memory nanodevices.

  20. Low-dimensional compounds containing cyano groups. XIV. Crystal structure, spectroscopic, thermal and magnetic properties of [CuL 2][Pt(China)4] complexes (L=ethylenediamine or N,N-dimethylethylenediamine)

    Potocnak, Ivan; Vavra, Martin; Cizmar, Erik; Tibenska, Katarina; Orendacova, Alzbeta; Steinborn, Dirk; Wagner, Christoph; Dusek, Michal; Fejfarova, Karla; Schmidt, Harry; Muller, Thomas; Orendac, Martin; Feher, Alexander

    2006-01-01

    Violet crystals of [Cu(en) 2 ][Pt(China) 4 ] and blue crystals of [Cu(dmen) 2 ][Pt(China) 4 ] were crystallized from the water-methanol solution containing CuCl 2 .2H 2 O, ethylenediamine (en) or N,N-dimethylethylenediamine (dmen) and K 2 [Pt(China) 4 ].3H 2 O. Both compounds were characterized using elemental analysis, infrared and UV-VIS spectroscopy, magnetic measurements, specific heat measurements and thermal analysis. X-ray structure analysis revealed chain-like structure in both compounds. The covalent chains are built of Cu(II) ions linked by [Pt(China) 4 ] 2- anions in the [111] and [101] direction, respectively. The Cu(II) atoms are hexacoordinated by four nitrogen atoms in the equatorial plane from two molecules of bidentate ligands L with average Cu-N distance of 2.022(2) and 2.049(4) A, respectively. Axial positions are occupied by two nitrogen atoms from bridging [Pt(China) 4 ] 2- anions at longer Cu-N distance of 2.537(2) and 2.600(5) A, respectively. Both materials are characterized by the presence of weak antiferromagnetic exchange coupling. Despite the one-dimensional (1D) character of the structure, the analysis of magnetic properties and specific heat at very low temperatures shows that [Cu(en) 2 ][Pt(China) 4 ] behaves as two-dimensional (2D) spatially anisotropic square lattice Heisenberg magnet, while more pronounced influence of interlayer coupling is observed in [Cu(dmen) 2 ][Pt(China) 4 ]. - Graphical abstract: Chain-like structure in [Cu(en) 2 ][Pt(China) 4 ] (R=H) and [Cu(dmen) 2 ][Pt(China) 4 ] (R=CH 3 ) compounds

  1. Theoretical simulations of the structural stabilities, elastic, thermodynamic and electronic properties of Pt3Sc and Pt3Y compounds

    Boulechfar, R.; Khenioui, Y.; Drablia, S.; Meradji, H.; Abu-Jafar, M.; Omran, S. Bin; Khenata, R.; Ghemid, S.

    2018-05-01

    Ab-initio calculations based on density functional theory have been performed to study the structural, electronic, thermodynamic and mechanical properties of intermetallic compounds Pt3Sc and Pt3Y using the full-potential linearized augmented plane wave(FP-LAPW) method. The total energy calculations performed for L12, D022 and D024 structures confirm the experimental phase stability. Using the generalized gradient approximation (GGA), the values of enthalpies formation are -1.23 eV/atom and -1.18 eV/atom for Pt3Sc and Pt3Y, respectively. The densities of states (DOS) spectra show the existence of a pseudo-gap at the Fermi level for both compounds which indicate the strong spd hybridization and directing covalent bonding. Furthermore, the density of states at the Fermi level N(EF), the electronic specific heat coefficient (γele) and the number of bonding electrons per atom are predicted in addition to the elastic constants (C11, C12 and C44). The shear modulus (GH), Young's modulus (E), Poisson's ratio (ν), anisotropy factor (A), ratio of B/GH and Cauchy pressure (C12-C44) are also estimated. These parameters show that the Pt3Sc and Pt3Y are ductile compounds. The thermodynamic properties were calculated using the quasi-harmonic Debye model to account for their lattice vibrations. In addition, the influence of the temperature and pressure was analyzed on the heat capacities (Cp and Cv), thermal expansion coefficient (α), Debye temperature (θD) and Grüneisen parameter (γ).

  2. Catalytic hydrodeoxygenation of 2-methoxy phenol and dibenzofuran over Pt/mesoporous zeolites

    Lee, Hyung Won; Jun, Bo Ram; Kim, Hannah; Kim, Do Heui; Jeon, Jong-Ki; Park, Sung Hoon; Ko, Chang Hyun; Kim, Tae-Wan; Park, Young-Kwon

    2015-01-01

    The hydrodeoxygenation of 2-methoxy phenol and dibenzofuran, which are representative model compounds of bio-oil, was performed using two different Pt/mesoporous zeolite catalysts, Pt/mesoporous Y and Pt/mesoporous MFI. The reforming of 2-methoxy phenol and dibenzofuran via catalytic hydrodeoxygenation was investigated using a batch reactor at 40 bar and 250 °C. The characteristics of the catalysts were analyzed by N 2 adsorption-desorption, X-ray diffraction, and NH 3 temperature programmed desorption. Pt/mesoporous zeolite catalysts containing both strong acid sites and mesopores showed the higher conversion of 2-methoxy phenol than Pt/SiO 2 and Pt/Si-MCM-48 with no acid sites, Pt/γ-Al 2 O 3 , and a mixture of mesoporous Y and Pt/SiO 2 , indicating the importance of both Pt and strong acid sites for high catalytic activity. Among the two Pt/mesoporous zeolite catalysts tested, the conversion of 2-methoxy phenol to cyclohexane over Pt/mesoporous Y was much higher than that over the Pt/mesoporous MFI. This was attributed to the better textural properties, such as surface area, pore volume and micropore size, compared to those of Pt/mesoporous MFI. The catalytic conversions of dibenzofuran obtained using two Pt/mesoporous zeolite catalysts were similar and the main products were 1,1′-bicyclohexyl, cyclopentylmethyl-cyclohexane and cyclohexane. In addition, the reaction mechanisms of 2-methoxy phenol and dibenzofuran over Pt/mesoporous zeolite were suggested. - Highlights: • HDO of 2-methoxy phenol and dibenzofuran was performed over Pt/mesoporous zeolites. • Pt/mesoporous zeolites have mesopores and strong acid sites. • Main product of HDO of 2-methoxy phenol was cyclohexane. • Main products of HDO of dibenzofuran were bicyclohexyl (BCH), i-BCH, and cyclohexane

  3. Interface architecture determined electrocatalytic activity of Pt on vertically oriented TiO(2) nanotubes.

    Rettew, Robert E; Allam, Nageh K; Alamgir, Faisal M

    2011-02-01

    The surface atomic structure and chemical state of Pt is consequential in a variety of surface-intensive devices. Herein we present the direct interrelationship between the growth scheme of Pt films, the resulting atomic and electronic structure of Pt species, and the consequent activity for methanol electro-oxidation in Pt/TiO(2) nanotube hybrid electrodes. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) measurements were performed to relate the observed electrocatalytic activity to the oxidation state and the atomic structure of the deposited Pt species. The atomic structure as well as the oxidation state of the deposited Pt was found to depend on the pretreatment of the TiO(2) nanotube surfaces with electrodeposited Cu. Pt growth through Cu replacement increases Pt dispersion, and a separation of surface Pt atoms beyond a threshold distance from the TiO(2) substrate renders them metallic, rather than cationic. The increased dispersion and the metallic character of Pt results in strongly enhanced electrocatalytic activity toward methanol oxidation. This study points to a general phenomenon whereby the growth scheme and the substrate-to-surface-Pt distance dictates the chemical state of the surface Pt atoms, and thereby, the performance of Pt-based surface-intensive devices.

  4. Facile synthesis of porous Pt botryoidal nanowires and their electrochemical properties

    Huang, Zhongyuan; Zhou, Haihui; Chen, Zhongxue; Zeng, Fanyan; Chen, Liang; Luo, Wucheng; Kuang, Yafei

    2014-01-01

    Highlights: • Porous Pt nanowires were synthesized by combination of soft and hard templets. • Te nanowires were used as the hard templet and reductant. • The Pt nanowires are composed of many small Pt nanoparticles and pores. • The Pt nanowires have very good electrochemical activity and stability. - Abstract: Long and porous Pt botryoidal nanowires (Pt BNWs) were facilely synthesized by combination of soft and hard templates accompanying chemical reduction of ascorbic acid and replacement of Te nanowires. This bis-template and bis-reductant method is proved to be an effective way to prepare nanowires with special structure. The scanning electron microscopy and transmission electron microscopy images show the as-prepared product is botryoidal nanowires with diameter of 20–30 nm and length of several micrometers. High resolution transmission electron microscopy shows the Pt botryoidal nanowires are composed of many small Pt nanoparticles (about 3 nm in diameter), which is just like that many grapes grow on the branch. These small nanoparticles make Pt nanowires have botryoidal and porous structure. Moreover, the diameter of Pt BNWs can be adjusted by changing the dosage of Pt precursor, polyvinylpyrrolidone and L-ascorbic acid. The electrocatalytic performance of Pt botryoidal nanowires is studied, which shows that the as-prepared Pt botryoidal nanowires have not only high activity but also good stability for oxygen reduction reaction

  5. Microwave-polyol synthesis and electrocatalytic performance of Pt/graphene nanocomposites

    Liao, Chien-Shiun; Liao, Chien-Tsao; Tso, Ching-Yu; Shy, Hsiou-Jeng

    2011-01-01

    Highlights: · One-pot microwave-polyol synthesis of Pt/graphene electrocatalyst. · Simultaneous formation of Pt nanoparticles and reduction of graphene oxide. · Electrocatalytic activities depend on the morphology of the deposited Pt particles. · Dense dispersion of isolated Pt particles with high electrochemical active surface. · Few particle clusters of Pt have large number of active sites for methanol oxidation. - Abstract: Graphene oxide (GO) prepared by the modified Hummers method is used as a support in the formation of a Pt/GO nanocomposite electrocatalyst by microwave-polyol synthesis. The effects of microwave reaction times on particle size, dispersion, and electrocatalytic performance of Pt nanoparticles are studied using wide-angle X-ray diffractometery, Raman spectroscopy, transmission electron microscopy and three-electrode electrochemical measurements. The results indicate that Pt nanoparticles nucleation and growth occur, and the particles are uniformly deposited on the GO nanosheets within a short time. The maximum electrochemical active surface area 85.71 m 2 g -1 for a Pt/GO reaction time of 5 min, is a result of the deposition of a dense dispersion of small Pt particles. The highest methanol oxidation peak current density, I f , of 0.59 A mg -1 occurs for a Pt/GO reaction time of 10 min and is due to the formation of interconnecting Pt particles clusters. This novel Pt/GO nanocomposite electrocatalyst with high electrocatalytic activities has the potential for use as an anode material in fuel cells.

  6. Synthesis and Characterization of Pt-loaded carbon nanostructures derived from polyaniline nanotubes

    Xu, Gong Da; Kim, Pil; Lee, Youn Sik [Div. of Chemical Engineering, Nanomaterials Processing Research Center, Chonbuk NationalUniversity, Jeonju (Korea, Republic of)

    2017-03-15

    Proton exchange membrane fuel cells (PEMFC) are one of the most advanced fuel cells for future energy, owing to their high conversion efficiency, quick start-up, rapid response to variable loading, and relatively low operating temperature, compared with of her conventional energy conversion devices. PANTs were synthesized to have various aspect ratios and inner diameters. As the aniline concentration increased, the PANTs’ inner diameter greatly decreased, but their outer diameters only slightly increased, leading to a decrease in their aspect ratios. Carbonization of PANTs resulted in the formation of corresponding CNSs. Pt nanoparticles were successfully formed on the CNSs under N{sub 2} or N{sub 2}/NH{sub 3} flow. The Pt nanoparticles of the Pt- CNS-N{sub 2} /NH{sub 3} catalysts were smaller in size, less aggregated, and more uniformly dispersed than those of the Pt- CNS-N{sub 2} catalysts. The ECSA values of Pt-CNS-N{sub 2} /NH{sub 3} were larger than those of Pt-CNS-N{sub 2} and Pt/C. The half wave potentials of the Pt-CNS-N{sub 2} catalysts were lower than those of the Pt-CNS-N{sub 2} /NH{sub 3} , and close to those of the Pt/C. The Pt-CNS-N{sub 2} /NH{sub 3} catalysts exhibited better kinetic performance than the Pt-CNS -N{sub 2} catalysts and Pt/C.

  7. Methanol and ethanol electroxidation using Pt electrodes prepared by the polymeric precursor method

    Freitas, R.G.; Santos, M.C.; Oliveira, R.T.S.; Bulhoes, L.O.S.; Pereira, E.C. [Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Centro Multidisciplinar para o Desenvolvimento de Materiais Ceramicos, Departamento de Quimica. Universidade Federal de Sao Carlos, C.P. 676, CEP 13565-905, Sao Carlos, SP (Brazil)

    2006-07-14

    The results of methanol and ethanol oxidation in acidic medium on Pt electrodes deposited on Ti substrate using the Pechini method are presented. In this route the metallic salts were dissolved in a mixture of ethylene glycol (EG) and citric acid (CA) forming a polyester network, which is painted onto a Ti substrate and then heat treated at 600{sup o}C in order to obtain the metallic Pt thin films. The X-ray diffraction analysis showed the presence of Pt pattern peaks. The presence of the (420) plane in a higher amount compared to bulk Pt was observed and the peak position of the planes (200) and (420) were displaced by approximately -0.3{sup o}. The roughness data presented almost the same values for Ti and Ti/Pt. The electrochemical characterization of the electrodes in 0.1M HClO{sub 4} showed a typical Pt voltammetric profile. Although the voltammetric profiles of Ti/Pt and bulk Pt were the same, the electrocatalytical behavior for methanol oxidation showed an enhancement of the oxidation current density peak, which increased by 170% compared to bulk platinum. Although, the current density peak for ethanol oxidation on Ti/Pt is smaller than for Pt, it began at 0.11V less positive than the same process on bulk Pt. The chronoamperometric experiments for methanol and ethanol oxidation on Ti/Pt increased by almost 934% and 440%, respectively, compared with Pt bulk. (author)

  8. Methanol and ethanol electroxidation using Pt electrodes prepared by the polymeric precursor method

    Freitas, R. G.; Santos, M. C.; Oliveira, R. T. S.; Bulhões, L. O. S.; Pereira, E. C.

    The results of methanol and ethanol oxidation in acidic medium on Pt electrodes deposited on Ti substrate using the Pechini method are presented. In this route the metallic salts were dissolved in a mixture of ethylene glycol (EG) and citric acid (CA) forming a polyester network, which is painted onto a Ti substrate and then heat treated at 600 °C in order to obtain the metallic Pt thin films. The X-ray diffraction analysis showed the presence of Pt pattern peaks. The presence of the (4 2 0) plane in a higher amount compared to bulk Pt was observed and the peak position of the planes (2 0 0) and (4 2 0) were displaced by approximately -0.3°. The roughness data presented almost the same values for Ti and Ti/Pt. The electrochemical characterization of the electrodes in 0.1 M HClO 4 showed a typical Pt voltammetric profile. Although the voltammetric profiles of Ti/Pt and bulk Pt were the same, the electrocatalytical behavior for methanol oxidation showed an enhancement of the oxidation current density peak, which increased by 170% compared to bulk platinum. Although, the current density peak for ethanol oxidation on Ti/Pt is smaller than for Pt, it began at 0.11 V less positive than the same process on bulk Pt. The chronoamperometric experiments for methanol and ethanol oxidation on Ti/Pt increased by almost 934% and 440%, respectively, compared with Pt bulk.

  9. Electrochemical quartz crystal microbalance analysis of the oxygen reduction reaction on Pt-based electrodes. Part 2: adsorption of oxygen species and ClO4(-) anions on Pt and Pt-Co alloy in HClO4 solutions.

    Omura, J; Yano, H; Tryk, D A; Watanabe, M; Uchida, H

    2014-01-14

    To gain deeper insight into the role of adsorbed oxygenated species in the O2 reduction reaction (ORR) kinetics on platinum and platinum-cobalt alloys for fuel cells, we carried out a series of measurements with the electrochemical quartz crystal microbalance (EQCM) and the rotating disk electrode (RDE) in acid solution. The effects of anion adsorption on the activities for the ORR were first assessed in HClO4 and HF electrolyte solutions at various concentrations. In our previous work (Part 1), we reported that the perchlorate anion adsorbs specifically on bulk-Pt, with a Frumkin-Temkin isotherm, that is, a linear relationship between Δm and log[HClO4]. Here, we find that the specific adsorption on the Pt-skin/Pt3Co alloy was significantly stronger than that on bulk-Pt, in line with its modified electronic properties. The kinetically controlled current density j(k) for the O2 reduction at the Pt-skin/Pt3Co-RDE was about 9 times larger than that of the bulk-Pt-RDE in 0.01 M HClO4 saturated with air, but the j(k) values on Pt-skin/Pt3Co decreased with increasing [HClO4] more steeply than in the case of Pt, due to the blocking of the active sites by the specifically adsorbed ClO4(-). We have detected reversible mass changes for one or more adsorbed oxygen-containing species (Ox = O2, O, OH, H2O) on the Pt-skin/Pt3Co-EQCM and Pt-EQCM in O2-saturated and He-purged 0.01 M HClO4 solutions, in which the specific adsorption of ClO4(-) anions was negligible. The coverages of oxygen species θ(Ox) on the Pt-skin/Pt3Co in the potential range from 0.86 to 0.96 V in the O2-saturated solution were found to be larger than those on pure Pt, providing strong evidence that the higher O2 reduction activity on the Pt3Co is correlated with higher θ(Ox), contrary to the conventional view.

  10. Residual Stresses In 3013 Containers

    Mickalonis, J.; Dunn, K.

    2009-01-01

    The DOE Complex is packaging plutonium-bearing materials for storage and eventual disposition or disposal. The materials are handled according to the DOE-STD-3013 which outlines general requirements for stabilization, packaging and long-term storage. The storage vessels for the plutonium-bearing materials are termed 3013 containers. Stress corrosion cracking has been identified as a potential container degradation mode and this work determined that the residual stresses in the containers are sufficient to support such cracking. Sections of the 3013 outer, inner, and convenience containers, in both the as-fabricated condition and the closure welded condition, were evaluated per ASTM standard G-36. The standard requires exposure to a boiling magnesium chloride solution, which is an aggressive testing solution. Tests in a less aggressive 40% calcium chloride solution were also conducted. These tests were used to reveal the relative stress corrosion cracking susceptibility of the as fabricated 3013 containers. Significant cracking was observed in all containers in areas near welds and transitions in the container diameter. Stress corrosion cracks developed in both the lid and the body of gas tungsten arc welded and laser closure welded containers. The development of stress corrosion cracks in the as-fabricated and in the closure welded container samples demonstrates that the residual stresses in the 3013 containers are sufficient to support stress corrosion cracking if the environmental conditions inside the containers do not preclude the cracking process.

  11. Residual Fragments after Percutaneous Nephrolithotomy

    Kaan Özdedeli

    2012-09-01

    Full Text Available Clinically insignificant residual fragments (CIRFs are described as asymptomatic, noninfectious and nonobstructive stone fragments (≤4 mm remaining in the urinary system after the last session of any intervention (ESWL, URS or PCNL for urinary stones. Their insignificance is questionable since CIRFs could eventually become significant, as their presence may result in recurrent stone growth and they may cause pain and infection due to urinary obstruction. They may become the source of persistent infections and a significant portion of the patients will have a stone-related event, requiring auxilliary interventions. CT seems to be the ultimate choice of assessment. Although there is no concensus about the timing, recent data suggests that it may be performed one month after the procedure. However, imaging can be done in the immediate postoperative period, if there are no tubes blurring the assessment. There is some evidence indicating that selective medical therapy may have an impact on decreasing stone formation rates. Retrograde intrarenal surgery, with its minimally invasive nature, seems to be the best way to deal with residual fragments.

  12. Residual number processing in dyscalculia.

    Cappelletti, Marinella; Price, Cathy J

    2014-01-01

    Developmental dyscalculia - a congenital learning disability in understanding numerical concepts - is typically associated with parietal lobe abnormality. However, people with dyscalculia often retain some residual numerical abilities, reported in studies that otherwise focused on abnormalities in the dyscalculic brain. Here we took a different perspective by focusing on brain regions that support residual number processing in dyscalculia. All participants accurately performed semantic and categorical colour-decision tasks with numerical and non-numerical stimuli, with adults with dyscalculia performing slower than controls in the number semantic tasks only. Structural imaging showed less grey-matter volume in the right parietal cortex in people with dyscalculia relative to controls. Functional MRI showed that accurate number semantic judgements were maintained by parietal and inferior frontal activations that were common to adults with dyscalculia and controls, with higher activation for participants with dyscalculia than controls in the right superior frontal cortex and the left inferior frontal sulcus. Enhanced activation in these frontal areas was driven by people with dyscalculia who made faster rather than slower numerical decisions; however, activation could not be accounted for by response times per se, because it was greater for fast relative to slow dyscalculics but not greater for fast controls relative to slow dyscalculics. In conclusion, our results reveal two frontal brain regions that support efficient number processing in dyscalculia.

  13. Residual number processing in dyscalculia

    Marinella Cappelletti

    2014-01-01

    Full Text Available Developmental dyscalculia – a congenital learning disability in understanding numerical concepts – is typically associated with parietal lobe abnormality. However, people with dyscalculia often retain some residual numerical abilities, reported in studies that otherwise focused on abnormalities in the dyscalculic brain. Here we took a different perspective by focusing on brain regions that support residual number processing in dyscalculia. All participants accurately performed semantic and categorical colour-decision tasks with numerical and non-numerical stimuli, with adults with dyscalculia performing slower than controls in the number semantic tasks only. Structural imaging showed less grey-matter volume in the right parietal cortex in people with dyscalculia relative to controls. Functional MRI showed that accurate number semantic judgements were maintained by parietal and inferior frontal activations that were common to adults with dyscalculia and controls, with higher activation for participants with dyscalculia than controls in the right superior frontal cortex and the left inferior frontal sulcus. Enhanced activation in these frontal areas was driven by people with dyscalculia who made faster rather than slower numerical decisions; however, activation could not be accounted for by response times per se, because it was greater for fast relative to slow dyscalculics but not greater for fast controls relative to slow dyscalculics. In conclusion, our results reveal two frontal brain regions that support efficient number processing in dyscalculia.

  14. Residual number processing in dyscalculia☆

    Cappelletti, Marinella; Price, Cathy J.

    2013-01-01

    Developmental dyscalculia – a congenital learning disability in understanding numerical concepts – is typically associated with parietal lobe abnormality. However, people with dyscalculia often retain some residual numerical abilities, reported in studies that otherwise focused on abnormalities in the dyscalculic brain. Here we took a different perspective by focusing on brain regions that support residual number processing in dyscalculia. All participants accurately performed semantic and categorical colour-decision tasks with numerical and non-numerical stimuli, with adults with dyscalculia performing slower than controls in the number semantic tasks only. Structural imaging showed less grey-matter volume in the right parietal cortex in people with dyscalculia relative to controls. Functional MRI showed that accurate number semantic judgements were maintained by parietal and inferior frontal activations that were common to adults with dyscalculia and controls, with higher activation for participants with dyscalculia than controls in the right superior frontal cortex and the left inferior frontal sulcus. Enhanced activation in these frontal areas was driven by people with dyscalculia who made faster rather than slower numerical decisions; however, activation could not be accounted for by response times per se, because it was greater for fast relative to slow dyscalculics but not greater for fast controls relative to slow dyscalculics. In conclusion, our results reveal two frontal brain regions that support efficient number processing in dyscalculia. PMID:24266008

  15. Assessment of the residual lifetime of the units 3 and 4 of the Kozloduy NPP

    Mojkinski, G.

    2011-01-01

    The purpose of the report is to present the methodology for the residual lifetime assessment for the buildings and facilities during the decommissioning. An analysis of the existing facilities and constructions is made and requirements for further exploitation are set. A quantitative assessment is made of the residual lifetime for the buildings and auxiliary objects for the units 3 and 4. A detailed analysis is made for the ventilation systems and other equipment. Recommendations are given for the extension of the equipment lifetime

  16. X-ray irradiation induced reversible resistance change in Pt/TiO2/Pt cells.

    Chang, Seo Hyoung; Kim, Jungho; Phatak, Charudatta; D'Aquila, Kenneth; Kim, Seong Keun; Kim, Jiyoon; Song, Seul Ji; Hwang, Cheol Seong; Eastman, Jeffrey A; Freeland, John W; Hong, Seungbum

    2014-02-25

    The interaction between X-rays and matter is an intriguing topic for both fundamental science and possible applications. In particular, synchrotron-based brilliant X-ray beams have been used as a powerful diagnostic tool to unveil nanoscale phenomena in functional materials. However, it has not been widely investigated how functional materials respond to the brilliant X-rays. Here, we report the X-ray-induced reversible resistance change in 40-nm-thick TiO2 films sandwiched by Pt top and bottom electrodes, and propose the physical mechanism behind the emergent phenomenon. Our findings indicate that there exists a photovoltaic-like effect, which modulates the resistance reversibly by a few orders of magnitude, depending on the intensity of impinging X-rays. We found that this effect, combined with the X-ray irradiation induced phase transition confirmed by transmission electron microscopy, triggers a nonvolatile reversible resistance change. Understanding X-ray-controlled reversible resistance changes can provide possibilities to control initial resistance states of functional materials, which could be useful for future information and energy storage devices.

  17. Preparation of PtSnCu/C and PtSn/C electrocatalysts and activation by dealloying processes for ethanol electrooxidation

    Crisafulli, Rudy

    2013-01-01

    PtSnCu/C (with different Pt:Sn:Cu atomic ratios) and PtSn/C (50:50) electrocatalysts were prepared by borohydride (BR) and alcohol-reduction (AR) processes using H 2 PtCl 6 .6H 2 O, SnCl 2 .2H 2 O and CuCl 2 .2H 2 O as metal sources, NaBH 4 and ethylene glycol as reducing agents, 2-propanol and ethylene glycol/water as solvents and carbon black as support. In a further step, these electrocatalysts were activated by chemical (CD) and electrochemical (ED) dealloying processes through acid treatment and thin porous coating technique, respectively. These materials were characterized by energy dispersive X-ray, Xray diffraction, transmission electron microscopy, line scan energy dispersive Xray and cyclic voltammetry. Electrochemical studies for ethanol electro-oxidation were performed by cyclic voltammetry, chronoamperometry and in single Direct Ethanol Fuel Cell using Membrane Electrode Assembly (MEA). The anodic effluents were analysed by gas chromatography. The X-ray diffractograms of the as-synthesized electrocatalysts showed the typical face-centered cubic structure (FCC) of platinum and its alloys. After dealloying, the X-ray diffractograms showed that the Pt FCC structure was preserved. The crystallite sizes of the assynthesized electrocatalysts were in the range of PtSnCu/C (50:40:10) AR/ED > PtSnCu/C (50:10:40) BR/CD. PtSn/C (50:50) BR/CD, PtSnCu/C (50:10:40) BR/CD, PtSnCu/C (50:40:10) AR/CD electrocatalysts and Pt/C BASF, PtSn/C (75:25) BASF commercial electrocatalysts were tested in single Direct Ethanol Fuel Cell. The results showed the following performance for ethanol electro-oxidation: PtSn/C (50:50) BR/CD > PtSnCu/C (50:40:10) AR/CD > PtSnCu/C > PtSn/C (75:25) BASF > PtSnCu/C (50:10:40) BR/CD > Pt/C BASF. (author)

  18. On Pták functions for bounded operators

    Abdellah El Kinani

    2014-10-01

    Full Text Available The purpose of this paper is to prove that if the Pták function p is an operator norm, on \\mathcal{B}(E, associated to a norm | . |, then (E, | . | is a pseudo-Hilbert space. As a consequence, we obtain that if \\mathcal{B}(E  is a C*-algebra, then E is a Hilbert space.

  19. Metal Induced Gap States on Pt/Ge(001)

    Oncel, N.; van Beek, W.J.; Poelsema, Bene; Zandvliet, Henricus J.W.

    2007-01-01

    Using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) we have studied the electronic properties of a novel, planar, metal semiconductor contact. For this purpose we take advantage of the unique properties of the Pt-modified Ge(001) surface, which consist of coexisting

  20. Magnetocrystalline anisotropy of FePt: a detailed view

    Khan, S.A.; Blaha, P.; Ebert, H.; Minár, J.; Šipr, Ondřej

    2016-01-01

    Roč. 94, č. 14 (2016), 1-10, č. článku 144436. ISSN 2469-9950 Institutional support: RVO:68378271 Keywords : magnetocrystalline anisotropy * FePt * LDA Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.836, year: 2016