WorldWideScience

Sample records for platinum metal thermocouples

  1. Metallic and ceramic thin film thermocouples for gas turbine engines.

    Science.gov (United States)

    Tougas, Ian M; Amani, Matin; Gregory, Otto J

    2013-11-08

    Temperatures of hot section components in today's gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges) for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today's engines, they have greater sensitivity than conventional wire thermocouples, and they are non-invasive to combustion aerodynamics in the engine. Thin film thermocouples based on platinum:palladium and indium oxynitride:indium tin oxynitride as well as their oxide counterparts have been developed for this purpose and have proven to be more stable than conventional type-S and type-K thin film thermocouples. The metallic and ceramic thin film thermocouples described within this paper exhibited remarkable stability and drift rates similar to bulk (wire) thermocouples.

  2. Metallic and Ceramic Thin Film Thermocouples for Gas Turbine Engines

    Directory of Open Access Journals (Sweden)

    Otto J. Gregory

    2013-11-01

    Full Text Available Temperatures of hot section components in today’s gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today’s engines, they have greater sensitivity than conventional wire thermocouples, and they are non-invasive to combustion aerodynamics in the engine. Thin film thermocouples based on platinum:palladium and indium oxynitride:indium tin oxynitride as well as their oxide counterparts have been developed for this purpose and have proven to be more stable than conventional type-S and type-K thin film thermocouples. The metallic and ceramic thin film thermocouples described within this paper exhibited remarkable stability and drift rates similar to bulk (wire thermocouples.

  3. A Comparison of Contemporary Gold Versus Platinum Thermocouples with NIST SRM 1749-Based Thermocouples and Reference Function

    Science.gov (United States)

    Coleman, M. J.; Wiandt, T. J.; Harper, T.

    2015-12-01

    Fluke Calibration (formerly Hart Scientific) in American Fork, Utah, USA is a manufacturer of temperature calibration instruments. The company manufactured reference standard gold versus platinum (Au-Pt) thermocouples from 1992 to about 2002. Manufacturing was halted in 2002 because a trend of poor curve-fit results was observed in new batches of wire. After reviewing the possible sources of the problem, it was decided to sample wire from multiple manufacturers and investigate ways to make the curve-fit work better. This paper presents the results from the study of the wire and a characterization technique to help improve characterization of thermocouples made with lower purity wire. Calibration results from NIST SRM material and older Fluke thermocouples are included as well to provide a means of comparison of contemporary wire to NIST SRM era wire.

  4. Improving the Quality of Thermocouple Wire Made of Platinum-rhodium Alloys

    Institute of Scientific and Technical Information of China (English)

    HORIKOV P.A.; MAMONOV S.N.; EFIMOV V.N.; RADKIN A.N.; DROZDOV D.E.

    2012-01-01

    For the manufacture of S-type thermocouple the so-called thermocouple wire of platinum and platinum-rhodium alloy is used.One of the main technical requirements for the quality of the wire,according to State Standard of Russia (GOST 10821),is the uniformity of its largest thermoelectric force (Thermo-emf) in the length different sections.It was found that a determining impact on the uniformity of the wire thermo-emf is the distribution of rhodium along the length of the wire.The impact of platinum- rhodium melt crystallization conditions on the inhomogeneity of wire manufactured from it.It was suggested that the chemical inhomogeneity of the wire is related to the liquation phase of platinum-rhodium alloy.

  5. Segmented metal nanowires as nanoscale thermocouples.

    Science.gov (United States)

    Shapira, E; Marchak, D; Tsukernik, A; Selzer, Y

    2008-03-26

    Segmented Au-Ni nanowires are demonstrated to be highly effective thermocouples with a spatial resolution of a few nanometers and a temporal resolution in the microsecond range. The performance of the devices is characterized by a self-heating procedure in which an ac heating current with frequency ω is applied on the wires while monitoring the resulting thermoelectric voltage V(TH) at 2ω using a lock-in technique. An analytical model is developed that enables one to determine the time response of the thermocouples from plots of V(TH) as a function of ω.

  6. Low-Temperature Drift in MIMS Base-Metal Thermocouples

    Science.gov (United States)

    Webster, E. S.

    2014-04-01

    Inhomogeneities are known to develop within thermoelements exposed to elevated temperatures, resulting in temperature measurement errors. While the Seebeck coefficient drift in base-metal thermocouples due to aging at temperatures over has been extensively investigated, there have been very few investigations into possible Seebeck changes at lower temperatures. Despite warnings about possible effects, most practitioners assume changes in homogeneity are either not significant or not able to develop at temperatures less than . This study reports on measurements of inhomogeneities in base-metal thermocouples arising from heat treatment at temperatures in the region of . Thermoelectric scans of thermocouples were carried out following exposure of a range of mineral-insulated metal-sheathed base-metal thermocouples, from two large manufacturers, of Types E, J, K, N, and T, to either a linear-gradient furnace within the range of to or uniform temperature zones of , , and . The experiments reveal noticeable drift in all base-metal types for temperatures as low as and exposure times as short as 1 h. The most sensitive thermoelement alloys appear to be Constantan, Alumel, and Nicrosil. It is concluded that the common working assumption that base-metal thermocouples suffer no thermally induced changes in the Seebeck coefficient below is false. This observation has significant implications for many high-stability monitoring and control systems reliant on base-metal thermocouples that operate in the range of to . Additionally, thermoelectric scanning of base-metal thermocouples should be carried out at temperatures well below to avoid erasure of strain effects or imprinting of new thermal signatures.

  7. Metallic and Ceramic Thin Film Thermocouples for Gas Turbine Engines

    OpenAIRE

    Gregory, Otto J.; Matin Amani; Ian M. Tougas

    2013-01-01

    Temperatures of hot section components in today’s gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges) for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stabil...

  8. Platinum metals in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Zereini, Fathi [Frankfurt Univ. (Germany). Dept. of Environmental Analytical Chemistry; Wiseman, Clare L.S. (ed.) [Toronto Univ. (Canada). School of the Environment

    2015-03-01

    This book contains the five chapters with the following topics: 1. SOURCES OF PGE EMISSIONS ELEMENTS: Sources of Platinum Group Elements (PGE) in the Environment; Impact of Platinum Group Element Emissions from Mining and Production Activities. 2. ANALYTICAL METHODS FOR THE DETERMINATION OF PGE IN BIOLOGICAL AND ENVIRONMENTAL MATRICES: Appraisal of Biosorption for Recovery, Separation and Determination of Platinum, Palladium and Rhodium in Environmental Samples; On the Underestimated Factors Influencing the Accuracy of Determination of Pt and Pd by Electrothermal Atomic Absorption Spectrometry in Road Dust Samples; Application of Solid Sorbents for Enrichment and Separation of Platinum Metal Ions; Voltammetric Analysis of Platinum in Environmental Matrices; Speciation Analysis of Chloroplatinates; Analysis of Platinum Group Elements in Environmental Samples: A Review. 3. OCCURRENCE, CHEMICAL BEHAVIOR AND FATE OF PGE IN THE ENVIRONMENT: Brazilian PGE Research Data Survey on Urban and Roadside Soils; Platinum, Palladium and Rhodium in a Bavarian Roadside Soil; Increase of Platinum Group Element Concentrations in Soils and Airborne Dust During the Period of Vehicular Exhaust Catalysts Introduction; Platinum-Group Elements in Urban Fluvial Bed Sediments-Hawaii; Long-Term Monitoring of Palladium and Platinum Contents in Road Dust of the City of Munich, Germany; Characterization of PGEs and Other Elements in Road Dusts and Airborne Particles in Houston, Texas; Accumulation and Distribution of Pt and Pd in Roadside Dust, Soil and Vegetation in Bulgaria; Increase of the Environmental Pt Concentration in the Metropolitan Area of Mexico City Associated to the Use of Automobile Catalytic Converters; Solubility of Emitted Platinum Group Elements (Pt, Pd and Rh) in Airborne Particulate Matter (PM10) in the Presence of Organic Complexing Agents; The Influence of Anionic Species (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup 2-}) on the Transformation and Solubility of Platinum in

  9. Platinum Group Metals New Material

    Institute of Scientific and Technical Information of China (English)

    XIE Ming; ZHANG Jiankang; WANG Saibei; HU Jieqiong; LIU Manmen; CHEN Yongtai; ZHANG Jiming; YANG Youcai; YANG Yunfeng; ZHANG Guoquan

    2012-01-01

    Platinum group metals (PGM) include six elements,namely Pt,Pd,Rh,Ir,Os and Ru.PGM and their alloys are the important fundamental materials for modern industry and national defense construction,they have special physical and chemical properties,widely used in metallurgy,chemical,electric,electronic,information,energy,environmental protection,aviation,aerospace,navigation and other high technology industry.Platinum group metals and their alloys,which have good plasticity and processability,can be processed to electrical contact materials,resistance materials,solder,electronic paste,temperature-measurement materials,elastic materials,magnetic materials and high temperature structural materials.

  10. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)

    2014-01-01

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

  11. Hysteresis Effects and Strain-Induced Homogeneity Effects in Base Metal Thermocouples

    Science.gov (United States)

    Pavlasek, P.; Elliott, C. J.; Pearce, J. V.; Duris, S.; Palencar, R.; Koval, M.; Machin, G.

    2015-03-01

    Thermocouples are used in a wide variety of industrial applications in which they play an important role for temperature control and monitoring. Wire inhomogeneity and hysteresis effects are major sources of uncertainty in thermocouple measurements. To efficiently mitigate these effects, it is first necessary to explore the impact of strain-induced inhomogeneities and hysteresis, and their contribution to the uncertainty. This article investigates homogeneity and hysteresis effects in Types N and K mineral-insulated metal-sheathed (MIMS) thermocouples. Homogeneity of thermocouple wires is known to change when mechanical strain is experienced by the thermoelements. To test this influence, bends of increasingly small radii, typical in industrial applications, were made to a number of thermocouples with different sheath diameters. The change in homogeneity was determined through controlled immersion of the thermocouple into an isothermal liquid oil bath at and was found to be very small at for Type K thermocouples, with no measureable change in Type N thermocouples found. An experiment to determine the hysteresis effect in thermocouples was performed on swaged, MIMS Type N and Type K thermocouples, in the temperature range from to . The hysteresis measurements presented simulate the conditions that thermocouples may be exposed to in industrial applications through continuous cycling over 136 h. During this exposure, a characteristic drift from the reference function has been observed but no considerable difference between the heating and cooling measurements was measureable. The measured differences were within the measurement uncertainties; therefore, no hysteresis was observed.

  12. Fate of platinum metals in the environment.

    Science.gov (United States)

    Pawlak, Justyna; Łodyga-Chruścińska, Elżbieta; Chrustowicz, Jakub

    2014-07-01

    For many years now automotive exhaust catalysts have been used to reduce the significant amounts of harmful chemical substances generated by car engines, such as carbon monoxide, nitrogen oxides, and aromatic hydrocarbons. Although they considerably decrease environmental contamination with the above-mentioned compounds, it is known that catalysts contribute to the environmental load of platinum metals (essential components of catalysts), which are released with exhaust fumes. Contamination with platinum metals stems mainly from automotive exhaust converters, but other major sources also exist. Since platinum group elements (PGEs): platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru) and iridium (Ir) seem to spread in the environment and accumulate in living organisms, they may pose a threat to animals and humans. This paper discusses the modes and forms of PGE emission as well as their impact on the environment and living organisms.

  13. Calculation of the Uncertainty of Cheap Metal Thermocouple%廉金属热电偶的不确定度计算

    Institute of Scientific and Technical Information of China (English)

    刘晔

    2016-01-01

    目前用量最大的廉金属热电偶是镍铬-镍硅热电偶(K型热电偶),为保证计量性能的准确可靠,采用双极法对其进行检定,用一等标准铂铑10-铂热电偶检定一支K型II级热电偶,检定点选取1000℃。文章重点介绍了该检定方法和示值误差的不确定度评定。%The current most widely used cheap metal thermocouple is chromel-silicel thermocouple (K type thermocouple). In order to ensure the accuracy and reliability of the calculation, we use bipolar method for its verification. The first standard Pt-Rh 10-platinum thermocouple is used to verify a K type Class II thermocouple, and the verification point is 1000℃. This paper mainly introduces the uncertainty evaluation of this verification method and the indication error.

  14. Measurement of the Inhomogeneity in Type B and Land-Jewell Noble-Metal Thermocouples

    Science.gov (United States)

    Webster, E. S.; Greenen, A.; Pearce, J.

    2016-07-01

    Inhomogeneity is the largest contributor to uncertainty in temperature measurements made with thermocouples, and the knowledge of inhomogeneity is essential if low-uncertainty measurements are required. Inhomogeneity is a particular problem for long-term applications at temperatures near or above 1500 ^{circ }hbox {C}, where pairs of alloyed noble-metal thermocouples must be used and the alloy components and potential contaminants become very mobile and cause large deviations in the Seebeck coefficient. While changes in inhomogeneity are a known and well-studied problem in noble-metal alloys at temperatures below 1100 ^{circ }hbox {C}, the effects are not well quantified at higher temperatures. This paper reports the first detailed measurements of inhomogeneity in a number of Type B and Land-Jewell thermocouples exposed to either short-term calibration up to 1600 ^{circ }hbox {C} or long-term in situ measurements for a period of approximately 3000 h at 1600 ^{circ }hbox {C}. The inhomogeneity is measured in a high-resolution scanner operating over the range from 600 ^{circ }hbox {C} to 900 ^{circ }hbox {C}. The results show that drifts of between 0.2 % and 0.6 % can be expected for reversible crystallographic and oxidation effects, whereas drift caused by irreversible contamination effects can be expected to be between 0.6 % and 1.1 %. It is also shown that the deviations in emfs caused by irreversible homogeneities in these thermocouples scale approximately linearly with temperature. This scalability allows uncertainties assessed at one temperature, to be extrapolated to other temperatures. Additionally it is shown that a preconditioning anneal at 1100 ^{circ }hbox {C} should be applied both before and after calibration to remove undesirable crystallographic and rhodium-oxidation effects.

  15. Exhaust system having a gold-platinum group metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ragle, Christie Susan [Havana, IL; Silver, Ronald G [Peoria, IL; Zemskova, Svetlana Mikhailovna [Edelstein, IL; Eckstein, Colleen J [Metamora, IL

    2011-12-06

    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  16. Thermodynamic ground states of platinum metal nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Aberg, D; Sadigh, B; Crowhurst, J; Goncharov, A

    2007-10-09

    We have systematically studied the thermodynamic stabilities of various phases of the nitrides of the platinum metal elements using density functional theory. We show that for the nitrides of Rh, Pd, Ir and Pt two new crystal structures, in which the metal ions occupy simple tetragonal lattice sites, have lower formation enthalpies at ambient conditions than any previously proposed structures. The region of stability can extend up to 17 GPa for PtN{sub 2}. Furthermore, we show that according to calculations using the local density approximation, these new compounds are also thermodynamically stable at ambient pressure and thus may be the ground state phases for these materials. We further discuss the fact that the local density and generalized gradient approximations predict different values of the absolute formation enthalpies as well different relative stabilities between simple tetragonal and the pyrite or marcasite structures.

  17. Problems and Characteristics of Russian Platinum Metals Exporters

    Institute of Scientific and Technical Information of China (English)

    ANDREEV A. M.; KELCHEVSKAYA N. R.

    2012-01-01

    The paper revealed the place and role of Russia in the global market of platinum metals,highlighted features of pricing in the export of Russian platinum group metals,the main problems of pricing in the export contracts related to the instability of markets and imperfect currency and customs legislation of the Russian Federation,proposed innovative ways to solutions to existing problems in the preparation and conclusion of export contracts.

  18. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others

    1999-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  19. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others

    1999-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  20. Nanoscale thermometry using point contact thermocouples.

    Science.gov (United States)

    Sadat, Seid; Tan, Aaron; Chua, Yi Jie; Reddy, Pramod

    2010-07-14

    Probing temperature fields with nanometer resolution is critical to understanding nanoscale thermal transport as well as dissipation in nanoscale devices. Here, we demonstrate an atomic force microscope (AFM)-based technique capable of mapping temperature fields in metallic films with approximately 10 mK temperature resolution and thermocouples on a grid. The local temperature at each point contact is obtained by measuring the thermoelectric voltage of the platinum-gold point contact and relating it to the local temperature. These results demonstrate a direct measurement of the temperature field of a metallic surface without using specially fabricated scanning temperature-probes.

  1. Platinum group metal nitrides and carbides: synthesis, properties and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanovskii, Alexander L [Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation)

    2009-04-30

    Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized. The extreme mechanical properties of platinoid nitrides and carbides, i.e., their high strength and low compressibility, are noted. The prospects of further studies and the scope of application of these compounds are discussed.

  2. Mineral resource of the month: platinum group metals

    Science.gov (United States)

    Loferski, Patricia J.

    2010-01-01

    The article focuses on platinum group metals (PGMs) and their properties. According to the author, PGMs, which include iridium, osmium, palladium, platinum, rhodium, and ruthenium, are among the rarest mineral commodities in the Earth's crust. PGMs are primarily used as catalytic converters that clean harmful exhaust from vehicle engines. They are also used in the chemical industry as catalysts in the production of nitric acid and in the petroleum refining industry.

  3. Method for bonding thin film thermocouples to ceramics

    Science.gov (United States)

    Kreider, Kenneth G.

    1993-01-01

    A method is provided for adhering a thin film metal thermocouple to a ceramic substrate used in an environment up to 700 degrees Centigrade, such as at a cylinder of an internal combustion engine. The method includes the steps of: depositing a thin layer of a reactive metal on a clean ceramic substrate; and depositing thin layers of platinum and a platinum-10% rhodium alloy forming the respective legs of the thermocouple on the reactive metal layer. The reactive metal layer serves as a bond coat between the thin noble metal thermocouple layers and the ceramic substrate. The thin layers of noble metal are in the range of 1-4 micrometers thick. Preferably, the ceramic substrate is selected from the group consisting of alumina and partially stabilized zirconia. Preferably, the thin layer of reactive metal is in the range of 0.015-0.030 micrometers (15-30 nanometers) thick. The preferred reactive metal is chromium. Other reactive metals may be titanium or zirconium. The thin layer of reactive metal may be deposited by sputtering in ultra high purity argon in a vacuum of approximately 2 milliTorr (0.3 Pascals).

  4. Recent strikes in South Africa’s platinum-group metal mines: effects upon world platinum-group metal supplies

    Science.gov (United States)

    Yager, Thomas R.; Soto-Viruet, Yadira; Barry, James J.

    2012-01-01

    The recent labor disputes over wages and working conditions that have affected South Africa’s three leading platinum-group metal (PGM) producers have affected an industry already plagued by market pressures and labor unrest and raised the specter of constraints in the world’s supply of these metals. Although low demand for these metals in 2011 and 2012 helped to offset production losses of recent years, and particularly those losses caused by the strikes in 2012, a prolonged resumption of strikes could cause severe shortages of iridium, platinum, rhodium, ruthenium, and, to a lesser extent, palladium.

  5. Thermocouple and Infrared Sensor-Based Measurement of Temperature Distribution in Metal Cutting

    Directory of Open Access Journals (Sweden)

    Abdil Kus

    2015-01-01

    Full Text Available In metal cutting, the magnitude of the temperature at the tool-chip interface is a function of the cutting parameters. This temperature directly affects production; therefore, increased research on the role of cutting temperatures can lead to improved machining operations. In this study, tool temperature was estimated by simultaneous temperature measurement employing both a K-type thermocouple and an infrared radiation (IR pyrometer to measure the tool-chip interface temperature. Due to the complexity of the machining processes, the integration of different measuring techniques was necessary in order to obtain consistent temperature data. The thermal analysis results were compared via the ANSYS finite element method. Experiments were carried out in dry machining using workpiece material of AISI 4140 alloy steel that was heat treated by an induction process to a hardness of 50 HRC. A PVD TiAlN-TiN-coated WNVG 080404-IC907 carbide insert was used during the turning process. The results showed that with increasing cutting speed, feed rate and depth of cut, the tool temperature increased; the cutting speed was found to be the most effective parameter in assessing the temperature rise. The heat distribution of the cutting tool, tool-chip interface and workpiece provided effective and useful data for the optimization of selected cutting parameters during orthogonal machining.

  6. Thermocouple and infrared sensor-based measurement of temperature distribution in metal cutting.

    Science.gov (United States)

    Kus, Abdil; Isik, Yahya; Cakir, M Cemal; Coşkun, Salih; Özdemir, Kadir

    2015-01-12

    In metal cutting, the magnitude of the temperature at the tool-chip interface is a function of the cutting parameters. This temperature directly affects production; therefore, increased research on the role of cutting temperatures can lead to improved machining operations. In this study, tool temperature was estimated by simultaneous temperature measurement employing both a K-type thermocouple and an infrared radiation (IR) pyrometer to measure the tool-chip interface temperature. Due to the complexity of the machining processes, the integration of different measuring techniques was necessary in order to obtain consistent temperature data. The thermal analysis results were compared via the ANSYS finite element method. Experiments were carried out in dry machining using workpiece material of AISI 4140 alloy steel that was heat treated by an induction process to a hardness of 50 HRC. A PVD TiAlN-TiN-coated WNVG 080404-IC907 carbide insert was used during the turning process. The results showed that with increasing cutting speed, feed rate and depth of cut, the tool temperature increased; the cutting speed was found to be the most effective parameter in assessing the temperature rise. The heat distribution of the cutting tool, tool-chip interface and workpiece provided effective and useful data for the optimization of selected cutting parameters during orthogonal machining.

  7. Enhancement of Platinum Cathode Catalysis by Addition of Transition Metals

    Science.gov (United States)

    Duong, Hung Tuan

    2009-01-01

    The sluggish kinetics of oxygen reduction reaction (ORR) contributes significantly to the loss of cathode overpotential in fuel cells, thus requiring high loadings of platinum (Pt), which is an expensive metal with limited supply. However, Pt and Pt-based alloys are still the best available electrocatalysts for ORR thus far. The research presented…

  8. Thin-Film Ceramic Thermocouples Fabricated and Tested

    Science.gov (United States)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Gregory, Otto J.; Blaha, Charles A.

    2004-01-01

    The Sensors and Electronics Technology Branch of the NASA Glenn Research Center is developing thin-film-based sensors for surface measurement in propulsion system research. Thin-film sensors do not require special machining of the components on which they are mounted, and they are considerably thinner than wire- or foil-based sensors. One type of sensor being advanced is the thin-film thermocouple, specifically for applications in high-temperature combustion environments. Ceramics are being demonstrated as having the potential to meet the demands of thin-film thermocouples in advanced aerospace environments. The maximum-use temperature of noble metal thin-film thermocouples, 1500 C (2700 F), may not be adequate for components used in the increasingly harsh conditions of advanced aircraft and next-generation launch vehicles. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically in the form of bulky rods or probes. As part of ASTP, Glenn's Sensors and Electronics Technology Branch is leading an in-house effort to apply ceramics as thin-film thermocouples for extremely high-temperature applications as part of ASTP. Since the purity of the ceramics is crucial for the stability of the thermocouples, Glenn's Ceramics Branch and Case Western Reserve University are developing high-purity ceramic sputtering targets for fabricating high-temperature sensors. Glenn's Microsystems Fabrication Laboratory, supported by the Akima Corporation, is using these targets to fabricate thermocouple samples for testing. The first of the materials used were chromium silicide (CrSi) and tantalum carbide (TaC). These refractory materials are expected to survive temperatures in excess of 1500 C. Preliminary results indicate that the thermoelectric voltage output of a thin-film CrSi versus TaC thermocouple is 15 times that of the standard type R (platinum-rhodium versus platinum) thermocouple, producing 20 mV with a 200

  9. 贵金属铠装热电偶的发展及应用%The Development and Application of Armored Thermocouple of Precious Metals

    Institute of Scientific and Technical Information of China (English)

    张健康; 刘毅; 李伟; 虞坤; 许昆; 罗锡明

    2016-01-01

    贵金属铠装热电偶具有特殊的结构和特性,对套管、偶丝、绝缘材料进行了介绍,列出了贵金属铠装热电偶相关标准,并介绍了其应用领域。对贵金属铠装热电偶的发展方向进行了展望。%The armored thermocouple of precious metals have special structures and properties. The thermowell, thermocouple wires, insulation material were introduced, the standards were listed and the applications of armored thermocouple of precious metals were described. Lastly, the development trends of armored thermocouple of precious metals were proposed.

  10. Platinum metals in magmatic sulfide ores

    Science.gov (United States)

    Naldrett, A.J.; Duke, J.M.

    1980-01-01

    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example. Copyright ?? 1980 AAAS.

  11. 76 FR 67793 - Notification of Expanded Pricing Grid for Precious Metals Products Containing Platinum and Gold...

    Science.gov (United States)

    2011-11-02

    ... United States Mint Notification of Expanded Pricing Grid for Precious Metals Products Containing Platinum..., 2009, outlining the new pricing methodology for numismatic products containing platinum and gold. Since that time, the price of platinum and gold has increased considerably, and is approaching the...

  12. Effect of Platinum Group Metal Doping in Magnesium Diboride Wires

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Alexiou, Aikaterini; Namazkar, Shahla

    2016-01-01

    The effect of some platinum group metals(PGM = Rh, Pd, and Pt) on the microstructure and critical current density of Cu/Nb-sheathed MgB2 wires has been studied using Mg1-x PGMxB2 powders with low doping levels. It was found that Pt and Pd do not enter the MgB2 lattice and have only limited....... The results are discussed in comparison with previous investigations using other transition metals for doping on the Mg site....

  13. THE SEPARATION OF BASE METALS FROM PLATINUM METALS BY ION EXCHANGE

    Institute of Scientific and Technical Information of China (English)

    JIANGLingen; HUANGYan

    1992-01-01

    In this paper the separation of base metals Fe,Co,Ni and Cu from the platinum metals on a cation exchanger column was studies.The convenient separation conditions are 0.5mol·dm-3 NaCl,pH=2. The recovery efficiency of Rh is 98%.

  14. Determination of Platinum Metals in Carbonaceous Mineral Raw Materials by Stripping Voltammetry

    OpenAIRE

    Kolpakova, Nina Alexandrovna; Oskina, Yuliya Aleksandrovna; Dyachenko, Elena Nikolaevna; Pshenichkin, Anatoliy Yakovlevich

    2015-01-01

    The paper considers the possibility of determining platinum metals in mineral raw materials by stripping voltammetry on a graphite electrode modified by metals. Stripping voltammetry method is characterized by low determination limit, wide intervals of determined content and high sensitivity. As a result of the research the conditions for the determination of gold, platinum and palladium by stripping voltammetry have been selected. The comparison of the results of gold, palladium and platinum...

  15. Potentiometric titration of gold, platinum, and some other precious metals

    Energy Technology Data Exchange (ETDEWEB)

    Selig, W.S.

    1991-02-04

    Gold, platinum, and several other platinum metals can be determined by titration with cetylpyridinium chloride (CPC). CPC forms a precipitate with AuCl{sub 4}{sup {minus}} and PtCl{sub 6}{sup 2{minus}}. Differentiation of AuCl{sub 4{minus}} and PtCl{sub 6}{sup 2{minus}} with this titrant is not possible; however, their sum can be determined. Titration with tetraphenylarsonium chloride at pH 1 is selective for tetrachloroaurate, which thus can be determined in the presence of hexachloroplatinate. Hexachloroosmate(IV), tetrachloroplatinite(II), tetrachloropalladate(II), hexachloropalladate(IV), and hexachloroiridate(IV) can also be determined potentiometrically vs. CPC. The indicating electrode is prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) (PVC) and dioctylphthalate (DOP) in tetrahydrofuran (THF). Gold in gold cyanide plating baths and in potassium aurocyanide can be determined by potentiometric titration vs standard silver nitrate, using a silver ion-selective indicating electrode. The monovalent gold need not be converted to the trivalent state with aqua regia, resulting in a considerable saving of time and effort. Free cyanide and aurocyanide can be titrated sequentially by this method. Chloride does not interfere and can, in fact, also be sequentially determined. 17 refs., 2 figs., 3 tabs.

  16. Palladium and platinum organochalcogenolates and their transformation into metal chalcogenides

    Indian Academy of Sciences (India)

    S Dey; S Narayan; A Singhal; V K Jain

    2000-06-01

    Platinum group metal chalcogenides find extensive applications in catalysis and in the electronic industry. To develop an efficient low temperature clean preparation of these materials, molecular routes have been explored. Thus the chemistry of mononuclear organochalcogenolates of the type [M(ER 1/4)2(PR3)2], binuclear benzylselenolates, [M2Cl2(∼-SeBz)2(PR3)2], allylpalladium complexes [Pd2(μ-ER)2(3-C4H7)2] and palladium/platinum sulphido/selenido-bridged complexes, [M2(μ-E)2L4] (M = Pd or Pt; E = S, Se or Te; L = tertiary phosphine ligand) has been investigated. All the complexes have been characterized by elemental analysis, NMR (1 H, 31P, 77Se, 195Pt) spectroscopy and in some cases by X-ray diffraction. The thermal behaviour of these complexes has been studied by TGA. The pyrolysis of allylpalladium complexes in refluxing xylene yields Pd4E as established by analysis and XRD patterns.

  17. Metal Oxide-Supported Platinum Overlayers as Proton-Exchange Membrane Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Abild-Pedersen, Frank; Studt, Felix

    2012-01-01

    We investigated the activity and stability of n=(1, 2, 3) platinum layers supported on a number of rutile metal oxides (MO2; M=Ti, Sn, Ta, Nb, Hf and Zr). A suitable oxide support can alleviate the problem of carbon corrosion and platinum dissolution in Pt/C catalysts. Moreover, it can increase t...

  18. Modeling platinum group metal complexes in aqueous solution.

    Science.gov (United States)

    Lienke, A; Klatt, G; Robinson, D J; Koch, K R; Naidoo, K J

    2001-05-07

    We construct force fields suited for the study of three platinum group metals (PGM) as chloranions in aqueous solution from quantum chemical computations and report experimental data. Density functional theory (DFT) using the local density approximation (LDA), as well as extended basis sets that incorporate relativistic corrections for the transition metal atoms, has been used to obtain equilibrium geometries, harmonic vibrational frequencies, and atomic charges for the complexes. We found that DFT calculations of [PtCl(6)](2-).3H(2)O, [PdCl(4)](2-).2H(2)O, and [RhCl(6)](3-).3H(2)O water clusters compared well with molecular mechanics (MM) calculations using the specific force field developed here. The force field performed equally well in condensed phase simulations. A 500 ps molecular dynamics (MD) simulation of [PtCl(6)](2-) in water was used to study the structure of the solvation shell around the anion. The resulting data were compared to an experimental radial distribution function derived from X-ray diffraction experiments. We found the calculated pair correlation functions (PCF) for hexachloroplatinate to be in good agreement with experiment and were able to use the simulation results to identify and resolve two water-anion peaks in the experimental spectrum.

  19. Production of Nanopowders of Platinum Metals Using the Chemical Reduction Method

    Institute of Scientific and Technical Information of China (English)

    PYATAKHINA E. S.; BUSLAYEVA T. M.; VOLCHKOVA E. V.; KHRISTICH E. A.; SERGEYEVA T. Yu.

    2012-01-01

    The literary data on the application of various methods for the production of nanopowders of platinum metals and alloys have been summarized,and the selection of the method of chemical reduction from salt solutions has been substantiated as the simplest and most affordable.The optimum conditions for the production of nanoparticles of metal palladium and platinum/cobalt alloy,using the effect of boranes with various structures,have been selected.

  20. Chemistry of Platinum and Palladium Metal Complexes in Homogeneous and Heterogeneous Catalysis: A Mini Review

    Directory of Open Access Journals (Sweden)

    Mehrban Ashiq

    2013-04-01

    Full Text Available Transition metal complexes of platinum and palladium are most widely used in catalysis. Many synthetic reactions have been carried out with such complexes (used as a catalyst which have specifically polymer ligands, through hydrosilylation, acetoxylation, hydrogenation, hydro-formylation, oligo-merisation and polymerization. Almost many platinum and palladium catalysts are heterogeneous in nature i.e. the reaction taking place on a solid surface. Now from few years homogeneous catalysts which are completely soluble in the liquid phase reactant, has acknowledged too much attention, yet having small industrial applications, mainly due to the striving of platinum and palladium complexes separation from the catalytic products. More recently a transitional type of platinum and palladium catalysts have been synthesized through attachment of the activated transition metal complexes on the surface of polymer support particularly insoluble which has been establish to offer encouraging new collection of catalysts for effective research on synthesis. Many of such complexes will be based on the palladium and platinum metals group. The major objective of this review is to inaugurate the relationship among the reactivity’s of homogeneous platinum and palladium complexes and heterogeneous complexes of these metals (those bonded to the surface of metals.

  1. Pyrometallurgical Recovery of Platinum Group Metals from Spent Catalysts

    Science.gov (United States)

    Peng, Zhiwei; Li, Zhizhong; Lin, Xiaolong; Tang, Huimin; Ye, Lei; Ma, Yutian; Rao, Mingjun; Zhang, Yuanbo; Li, Guanghui; Jiang, Tao

    2017-09-01

    As an important secondary resource with abundant platinum group metals (PGMs), spent catalysts demand recycling for both economic and environmental benefits. This article reviews the main pyrometallurgical processes for PGM recovery from spent catalysts. Existing processes, including smelting, vaporization, and sintering processes, are discussed based in part on a review of the physiochemical characteristics of PGMs in spent catalysts. The smelting technology, which produces a PGM-containing alloy, is significantly influenced by the addition of various collectors, such as lead, copper, iron, matte, or printed circuit board (PCB), considering their chemical affinities for PGMs. The vaporization process can recover PGMs in vapor form at low temperatures (250-700°C), but it suffers high corrosion and potential environmental and health risks as a result of involvement of the hazardous gases, mainly Cl2 and CO. The sintering process serves as a reforming means for recycling of the spent catalysts by in situ reduction of their oxidized PGMs components. Among these processes, the smelting process seems more promising although its overall performance can be further improved by seeking a suitable target-oriented collector and flux, together with proper pretreatment and process intensification using an external field.

  2. Platinum group metal recovery and catalyst manufacturing process

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. S.; Kim, Y. S.; Yoo, J. H.; Lee, H. S.; Ahn, D. H.; Kim, K. R.; Lee, S. H.; Paek, S. W.; Kang, H. S.

    1998-03-01

    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metal such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solution was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400 m{sup 2}/g. The content of palladium impregnated on the support was 10 wt.%. Hydrogen isotope exchange efficiency of 93 % to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its actively is unimportant as in nuclear industries. (author). 63 refs., 38 tabs., 36 figs.

  3. Friction behavior of members of the platinum metals group with gold

    Science.gov (United States)

    Buckley, D. H.

    1975-01-01

    The adhesion and friction behavior of the platinum metals group was examined with clean surfaces and surfaces selectively contaminated with oxygen, vinyl chloride (C2H3Cl), and methyl mercaptan (CH3SH). A pin or disk specimen configuration was used with the pin being a single crystal of gold of the (111) orientation and with the platinum metal disks also being single crystals of the (111) or (0001) orientation. Loads applied ranged from 1 to 10 g and a sliding velocity of 0.7 mm/min was employed. Results indicate adhesion and transfer of gold to all of the platinum metals. Despite this observation friction differences existed among the metals in the group. These differences are related to surface chemical activity. Adsorption of various friction reducing species was selective. With some adsorbates present strong adhesive forces between metals were still observed.

  4. Electronic metal-support interaction enhanced oxygen reduction activity and stability of boron carbide supported platinum

    Science.gov (United States)

    Jackson, Colleen; Smith, Graham T.; Inwood, David W.; Leach, Andrew S.; Whalley, Penny S.; Callisti, Mauro; Polcar, Tomas; Russell, Andrea E.; Levecque, Pieter; Kramer, Denis

    2017-06-01

    Catalysing the reduction of oxygen in acidic media is a standing challenge. Although activity of platinum, the most active metal, can be substantially improved by alloying, alloy stability remains a concern. Here we report that platinum nanoparticles supported on graphite-rich boron carbide show a 50-100% increase in activity in acidic media and improved cycle stability compared to commercial carbon supported platinum nanoparticles. Transmission electron microscopy and x-ray absorption fine structure analysis confirm similar platinum nanoparticle shapes, sizes, lattice parameters, and cluster packing on both supports, while x-ray photoelectron and absorption spectroscopy demonstrate a change in electronic structure. This shows that purely electronic metal-support interactions can significantly improve oxygen reduction activity without inducing shape, alloying or strain effects and without compromising stability. Optimizing the electronic interaction between the catalyst and support is, therefore, a promising approach for advanced electrocatalysts where optimizing the catalytic nanoparticles themselves is constrained by other concerns.

  5. X-ray characterization of platinum group metal catalysts

    Science.gov (United States)

    Peterson, Eric J.

    Platinum group metals (PGMs) are used extensively as catalysts, employed in several sectors of the world energy economy. Fuel cells employing PGM catalysts show promise as power sources in the proposed hydrogen economy, using alcohols as hydrogen storage media. Currently, the most economically important application for PGMs is for the mitigation of emissions from internal combustion engines via catalytic converters. In all applications, efficient use of these expensive metals to fabricate robust catalysts is of the utmost importance. Understanding the catalyst structure/property relationship is the key to the improvement of existing catalysts and the discovery of new catalysts. For example, catalyst particle size can have profound effects on catalyst activity, as in the case of gold nanoparticles. Catalyst particle size control and stability is also important for the efficient use of PGM metals and catalyst deactivation prevention. The challenge is to identify and characterize structural features and determine if and how these features may relate to catalytic properties. The ultimate goal is to simultaneously measure catalyst structural characteristics and catalytic properties under operando conditions, unambiguously establishing the structure/property link. X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are important techniques used for the characterization of PGM catalysts. Microstructural information such as crystallite size, as small as ~ 1 nm, and microstrain can be obtained from Bragg diffraction peak shapes in X-ray diffraction patterns, and long range crystal structure information is found in the intensities and positions of these peaks. In contrast, X-ray absorption spectroscopy provides information about the chemical state and local structure of selected atoms. From the average nearest neighbor coordination numbers, crystallite sizes can also be inferred, with particularly high sensitivity in the sub-nm size range. Electron microscopy

  6. The platinum group metals in Younger Dryas Horizons are terrestrial

    Science.gov (United States)

    Wu, Y.; Wikes, E.; Kennett, J.; West, A.; Sharma, M.

    2009-12-01

    The Younger Dryas (YD) event, which began 12,900 years ago, was a period of abrupt and rapid cooling in the Northern Hemisphere whose primary cause remains unclear. The prevalent postulated mechanism is a temporary shutdown of the thermohaline circulation following the breakup of an ice dam in North America. Firestone et al. (2007) proposed that the cooling was triggered by multiple cometary airbursts and/or impacts that engendered enormous environmental changes and disrupted the thermohaline circulation. The evidence in support for this hypothesis is a black layer in North America and in Europe marking the YD boundary containing charcoal, soot, carbon spherules and glass-like carbon suggesting extensive and intense forest fires. This layer is also enriched in magnetic grains high in iridium, magnetic microspherules, fullerenes containing extraterrestrial He-3, and nanodiamonds. Whereas the nanodiamonds could be produced in an impact or arrive with the impactor, the cometary burst/impact hypothesis remains highly controversial as the YD horizon lacks important impact markers such as craters, breccias, tektites and shocked minerals. Firestone et al. (2007) contend that bulk of Ir found at the YD boundary is associated with magnetic grains. The key issue is whether this Ir is meteorite derived. We used Ir and Os concentrations and Os isotopes to investigate the provenance of the platinum group metals in the YD horizon. The bulk sediment samples from a number of North American YD sites (Blackwater Draw, Murray Springs, Gainey, Sheriden Cave, and Myrtle Beach) and a site in Europe (Lommel) do not show any traces of meteorite derived Os and Ir. The [Os] = 2 to 45 pg/g in these sediments and the 187Os/188Os ratios are similar to the upper continental crustal values (~1.3), much higher than those in meteorites (0.13). Higher [Os] is observed in Blackwater Draw (= 194 pg/g). However, the Os/Ir ratio in Blackwater Draw is 5 (not 1 as expected for a meteorite) and 187Os/188

  7. Reviews of Metallurgical Technology to Recovery Platinum Group Metals from Secondary Resource in China

    Institute of Scientific and Technical Information of China (English)

    GUO Junmei; HE Xiaotang; WANG Huan; WU Xilong; ZHAO Yu; LI Yong; LI Kun; HAN Shouli

    2012-01-01

    China is extremely poor in mineral resources of Platinum Group Metals (PGMs),productive output of PGMs from mineral resource is 2.5 tons per year.At the same time,China is the biggest PGMs consumption country in the world,the mineral resource of PGMs is critical shortage,it shows the importance of recycling the secondary resource of PGMs.Sino-Platinum Metals Resource (Yimen) Co.,Ltd.is the leader in recycling of PGMs from secondary resource,and has made outstanding contributions to China PGMs secondary resources recycling.This article elucidates the current situation of secondary resources recovery and development of metallurgical technology for PGMs.

  8. Platinum redispersion on metal oxides in low temperature fuel cells

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Cerri, Isotta; Nagami, Tetsuo

    2013-01-01

    in detail; however, due to different operating conditions it is not straightforward to link the chemical and the electrochemical environment. The largest differences reflect in (1) the oxidation state of the surface (the oxygen species coverage), (2) temperature and (3) the possibility of platinum...

  9. Self-Validating Thermocouple

    Science.gov (United States)

    Perotti, Jose M. (Inventor); Mata, Carlos T. (Inventor); Santiago, Josephine B. (Inventor); Vokrot, Peter (Inventor); Zavala, Carlos E. (Inventor); Burns, Bradley M. (Inventor)

    2010-01-01

    Self-Validating Thermocouple (SVT) Systems capable of detecting sensor probe open circuits, short circuits, and unnoticeable faults such as a probe debonding and probe degradation are useful in the measurement of temperatures. SVT Systems provide such capabilities by incorporating a heating or excitation element into the measuring junction of the thermocouple. By heating the measuring junction and observing the decay time for the detected DC voltage signal, it is possible to indicate whether the thermocouple is bonded or debonded. A change in the thermal transfer function of the thermocouple system causes a change in the rise and decay times of the thermocouple output. Incorporation of the excitation element does not interfere with normal thermocouple operation, thus further allowing traditional validation procedures as well.

  10. Peruvian perovskite Between Transition-metal to PGM/PlatinumGroupMetal Catalytic Fusion

    Science.gov (United States)

    Maksoed, Wh-

    2016-11-01

    Strongly correlated electronic materials made of simple building blocks, such as a transition-metal ion in an octahedral oxygen cage forming a perovskite structure- Dagotto & Tokura for examples are the high-temperature superconductivity & the CMR/Colossal Magnetoresistance . Helium-4 denotes from LC Case,ScD: "Catalytic Fusion of Deuterium into Helium-4"- 1998 dealt with gaseous D2- "contacted with a supported metallic catalyst at superatmospheric pressure". The catalyst is a platinum-group metal, at about 0.5% - 1% by weight, on activated C. Accompanies Stephen J Geier, 2010 quotes "transition metal complexes", the Energy thus produced is enormous, and because the deuterium is very cheap in the form of heavy water (less than US 1/g), the fuel cost is very low (<<1 %/KwH). "The oceans contain enough deuterium to satisfy the Earth's energy needs for many millions of year" to keep "maria"/Latin name of seas &Deuteronomy to be eternally preserves. Heartfelt Gratitudes to HE. Mr. Prof. Ir. HANDOJO.

  11. 铠装贵金属热电偶测量端位置的确定方法%Method for Determining Sheathed Noble Metal Thermocouple Measuring End Position

    Institute of Scientific and Technical Information of China (English)

    侯运安; 赵雪茹; 王兵利; 苏剑

    2015-01-01

    Accurate positioning of measuring ends of thermocouples has an important influence on the calibration and use of thermocouples, especially for armored noble metal thermocouples. It is impossible to accurately identify the position of thermocouple measuring ends inside protec-tion tubes by visual inspection, and therefore the top of protection tubes is chosen as the position for measuring ends in the calibration and use processes of thermocouples. However, through field test, the measuring ends of armored noble metal thermocouples are not located at the top of protection tubes. This paper provides a method for accurate positioning of armored noble metal thermocouple measuring ends.%热电偶测量端位置的准确定位对于热电偶的校准和使用有着重要影响,特别对于铠装贵金属热电偶来说,由于无法通过肉眼准确识别保护管内部热电偶测量端的位置,因此在热电偶检定和使用过程中一般将其外保护管顶部作为测量端所在位置。然而通过现场试验发现,铠装贵金属热电偶测量端一般并不位于保护管顶部,本文提供了一种准确定位铠装贵金属热电偶测量端的方法。

  12. Thin film ceramic thermocouples

    Science.gov (United States)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  13. Fabrication of Pt/ITO Thin-Film Thermocouple on Metal Substrates%金属基Pt/ITO薄膜热电偶的制备

    Institute of Scientific and Technical Information of China (English)

    赵文雅; 蒋洪川; 陈寅之; 张万里; 刘兴钊; 彭少龙; 唐磊

    2013-01-01

    采用多层膜结构制备了金属基Pt/ITO薄膜热电偶,薄膜热电偶由Ni基合金基片、NiCrAlY过渡层、热生长Al2O3层、Al2O3绝缘层、Pt/ITO功能层和Al2O3保护层构成.静态标定结果表明:样品的平均塞贝克系数为107.45 μV/℃.测试温度可达到1000℃.时效处理可以有效提高薄膜热电偶的输出热电势.%The Pt/ITO thin-film thermocouples with multilayer structure are fabricated on metal substrates. The thin-film thermocouple is composed of Ni-base alloy substrate, NiCrAlY buffer layer, thermal growth A12O3 layer, A12O3 insulating layer, Pt/ITO function layer and A12O3 protective layer. The results of the static calibration of the sample show that the average Seebeck coefficient is about 107.45 μV /℃. The test temperature can be up to 1000℃. The thermoelectric power of the sample can be effectively improved by aging treatment.

  14. Do Scarce Precious Metals Equate to Safe Harbor Investments? The Case of Platinum and Palladium

    Directory of Open Access Journals (Sweden)

    John Francis T. Diaz

    2016-01-01

    Full Text Available This research establishes the predictability and safe harbor properties of two scarce precious metals, namely, platinum and palladium. Utilizing their spot prices, the study concludes intermediate memory in the return structures of both precious metals, which implies the instability of platinum and palladium returns’ persistency in the long run. However, both the ARFIMA-FIGARCH and the ARFIMA-FIAPARCH models confirm long-memory properties in the volatility of the two spot prices. The leverage effects phenomenon is not also present based on the ARFIMA-APARCH and ARFIMA-FIAPARCH models, which may possibly conclude the resilience of both precious metals against increased volatility. However, further tests proved that only platinum has a symmetric volatility response to shocks with the presence of negative gamma parameter, which proves that only platinum can be considered a safe harbor investment, because negative and positive shocks have equal effects on their returns and volatilities. Comparing the four models utilized in this study, the combined ARFIMA-FIAPARCH models are the best fitting model to characterize both precious metals’ spot prices.

  15. Side-welded fast response sheathed thermocouple

    Science.gov (United States)

    Carr, K.R.

    A method of fabricating the measuring junction of a grounded-junction sheathed thermocouple to obtain fast time response and good thermal cycling performance is provided. Slots are tooled or machined into the sheath wall at the measuring junction, the thermocouple wires are laser-welded into the slots. A thin metal closure cap is then laser-welded over the end of the sheath. Compared to a conventional grounded-junction thermocouple, the response time is 4 to 5 times faster and the thermal shock and cycling capabilities are substantially improved.

  16. Attaching Thermocouples by Peening or Crimping

    Science.gov (United States)

    Murtland, Kevin; Cox, Robert; Immer, Christopher

    2006-01-01

    Two simple, effective techniques for attaching thermocouples to metal substrates have been devised for high-temperature applications in which attachment by such conventional means as welding, screws, epoxy, or tape would not be effective. The techniques have been used successfully to attach 0.005- in. (0.127-mm)-diameter type-S thermocouples to substrates of niobium alloy C-103 and stainless steel 416 for measuring temperatures up to 2,600 F (1,427 C). The techniques are equally applicable to other thermocouple and substrate materials. In the first technique, illustrated in the upper part of the figure, a hole slightly wider than twice the diameter of one thermocouple wire is drilled in the substrate. The thermocouple is placed in the hole, then the edge of the hole is peened in one or more places by use of a punch (see figure). The deformed material at the edge secures the thermocouple in the hole. In the second technique a hole is drilled as in the first technique, then an annular relief area is machined around the hole, resulting in structure reminiscent of a volcano in a crater. The thermocouple is placed in the hole as in the first technique, then the "volcano" material is either peened by use of a punch or crimped by use of sidecutters to secure the thermocouple in place. This second technique is preferable for very thin thermocouples [wire diameter .0.005 in. (.0.127 mm)] because standard peening poses a greater risk of clipping one or both of the thermocouple wires. These techniques offer the following advantages over prior thermocouple-attachment techniques: . Because these techniques involve drilling of very small holes, they are minimally invasive . an important advantage in that, to a first approximation, the thermal properties of surrounding areas are not appreciably affected. . These techniques do not involve introduction of any material, other than the substrate and thermocouple materials, that could cause contamination, could decompose, or oxidize

  17. Platinum impact assessment

    OpenAIRE

    Yip, Joyce Pui Yan

    2007-01-01

    This paper presents a comprehensive strategic analysis of Company X's strategies to mitigate its risks from volatile platinum prices, since Platinum is a critical component of fuel cells. It is recommended that Company X consider leasing platinum to lower cash flow requirements to meet its platinum demand over the next 5 years. A shorter platinum leasing period will reduce Company X's platinum market risk. OEMs can set up metal accounts with catalyst suppliers to eliminate Company X from plat...

  18. STUDY ON THE INTERACTION BETWEEN POLYVINYLPYRROLIDONE AND PLATINUM METALS DURING THE FORMATION OF THE COLLOIDAL METAL NANOPARTICLES

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Several PVP-stabilized colloidal platinum metals nanoparticles have been synthesized and characterized by FTIR and TEM.Comparing with the pure PVP,carbonyl groups of PVP in the mixture of PVP and the metal precursors or in the PVP-stabilized metal nanoparticles have obvious peak shifts in FTIR spectra.The peak shifts reveal the interaction between PVP and the metal species.The interaction between PVP and metal precursors has effect on the formation of the colloidal metal nanoparticles.Strength of the interaction between PVP and metal nanoparticles has direct influence on the stability and the size of the PVP-stabilized metal nanoparticles.Therein,species of the metal precursors and amount of the stabilizer are main factors on the strength of the interaction.

  19. Connecting to Thermocouples with Fewer Lead Wires

    Science.gov (United States)

    Goldsby, Jon C.

    2003-01-01

    A simple technique has been devised to reduce the number of lead wires needed to connect an array of thermocouples to the instruments (e.g., voltmeters) used to read their output voltages. Because thermocouple wires are usually made of expensive metal alloys, reducing the number of lead wires can effect a considerable reduction in the cost of such an array. Reducing the number of wires also reduces the number of terminals and the amount of space needed to accommodate the wires.

  20. Platinum Group Metal Recycling Technology Development - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Shore

    2009-08-19

    BASF Catalysts LLC, formerly Engelhard Corporation, has completed a project to recover Pt from PEM fuel cell membrane electrode assemblies. The project, which began in 2003, has met the project objective of an environmentally-friendly, cost-effective method for recovery of platinum without release of hydrogen fluoride. This has been achieved using a combination of milling, dispersion and acid leaching. 99% recovery of Pt was achieved, and this high yield can be scaled up using one vessel for a single leach and rinse. Leaching was been successfully achieved using a 10% solids level, double the original target. At this solids content, the reagent and utility costs represent ~0.35% of the Pt value of a lot, using very conservative assumptions. The main cost of the process is capital depreciation, followed by labor.

  1. HIGHLY REFRACTORY CRUCIBLES OF STABILIZED ZIRCONIA FOR INDUCTION MELTING OF THE PLATINUM GROUP METALS, FABRICATED BY VIBROCASTING

    Directory of Open Access Journals (Sweden)

    V. V. Primachenko

    2012-01-01

    Full Text Available As the result of the studies at PJSC « UKRNIIO them. A.S.Berezhnogo» the technology and commercial production of crucibles from stabilized zirconia for the smelting of platinum group metals are develop

  2. Noble Metal Catalysts for Mercury Oxidation in Utility Flue Gas: Gold, Palladium and Platinum Formulations

    Energy Technology Data Exchange (ETDEWEB)

    Presto, A.A.; Granite, E.J

    2008-07-01

    The use of noble metals as catalysts for mercury oxidation in flue gas remains an area of active study. To date, field studies have focused on gold and palladium catalysts installed at pilot scale. In this article, we introduce bench-scale experimental results for gold, palladium and platinum catalysts tested in realistic simulated flue gas. Our initial results reveal some intriguing characteristics of catalytic mercury oxidation and provide insight for future research into this potentially important process.

  3. Leaching platinum-group metals in a sulfuric acid/chloride solution

    Science.gov (United States)

    Mahmoud, M. H. H.

    2003-04-01

    A leaching process was established based on the ability of platinum-group metals to form stable chloro-complexes in acidic chloride solutions. Industrial catalyst losses were examined for the recovery of platinum, palladium, and rhodium by leaching with a mixture of sulfuric acid and sodium chloride to avoid using aqua regia or autoclave conditions. Extraction of platinum and rhodium in 60% H2SO4 at 135°C steadily increased with increasing NaCl concentrations reaching 95% and 85%, respectively, at 0.1 M NaCl after two hours. By comparison, palladium was dissolved more quickly but also reached 85% under the same conditions. Extraction of each metal increased with temperatures up to 125°C but plateaued at higher temperatures. Similar behavior was observed with increasing H2SO4 concentrations up to 60%. More than 99% extraction of each metal was obtained after ten hours using 0.1 M NaCl and 60% H2SO4 at 125°C.

  4. ITS-90 Thermocouple Database

    Science.gov (United States)

    SRD 60 NIST ITS-90 Thermocouple Database (Web, free access)   Web version of Standard Reference Database 60 and NIST Monograph 175. The database gives temperature -- electromotive force (emf) reference functions and tables for the letter-designated thermocouple types B, E, J, K, N, R, S and T. These reference functions have been adopted as standards by the American Society for Testing and Materials (ASTM) and the International Electrotechnical Commission (IEC).

  5. Meeting report on 8th International Symposium on Platinum and Other Metal Coordination Compounds in Cancer Chemotherapy.

    Science.gov (United States)

    Kelland, L R

    1999-10-01

    The platinum-based drugs, cisplatin and carboplatin, represent major agents in the chemotherapeutic treatment of a variety of types of cancer. Novel, "third-generation" agents aimed at broadening the clinical activity of this class of drug are currently undergoing clinical evaluation. These include oxaliplatin, ZD0473 and BBR3464. Clinical trials and preclinical studies are also being conducted with liposomal (SPI-077 and L-NDDP) and polymeric platinum complexes (linked to HPMA or albumin). Combination studies of cisplatin/carboplatin with other anticancer drugs such as gemcitabine and UCN-01 (7-hydroxystaurosporine) and agents designed to reduce platinum drug toxicities (e.g., BNP-7787, DIMESNA) are ongoing. Preclinically, there is interest in trans platinum complexes, terpyridine platinum(II) complexes and other metal-containing agents (ruthenium and gold).

  6. Hydrothermal synthesis of platinum-group-metal nanoparticles by using HEPES as a reductant and stabilizer.

    Science.gov (United States)

    So, Man-Ho; Ho, Chi-Ming; Chen, Rong; Che, Chi-Ming

    2010-06-01

    Platinum-group-metal (Ru, Os, Rh, Ir, Pd and Pt) nanoparticles are synthesized in an aqueous buffer solution of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (200 mM, pH 7.4) under hydrothermal conditions (180 degrees C). Monodispersed (monodispersity: 11-15%) metal nanoparticles were obtained with an average particle size of less than 5 nm (Ru: 1.8+/-0.2, Os: 1.6+/-0.2, Rh: 4.5+/-0.5, Ir: 2.0+/-0.3, Pd: 3.8+/-0.4, Pt: 1.9+/-0.2 nm). The size, monodispersity, and stability of the as-obtained metal nanoparticles were affected by the HEPES concentration, pH of the HEPES buffer solution, and reaction temperature. HEPES with two tertiary amines (piperazine groups) and terminal hydroxyl groups can act as a reductant and stabilizer. The HEPES molecules can bind to the surface of metal nanoparticles to prevent metal nanoparticles from aggregation. These platinum-group-metal nanoparticles could be deposited onto the surface of graphite, which catalyzed the aerobic oxidation of alcohols to aldehydes.

  7. A comparison of the marginal and internal adaptation of titanium and gold-platinum-palladium metal ceramic crowns.

    Science.gov (United States)

    Valderrama, S; Van Roekel, N; Andersson, M; Goodacre, C J; Munoz, C A

    1995-01-01

    The marginal and internal adaptation of metal ceramic crowns fabricated by electrical discharge machining and conventional metal ceramic alloys were compared. The crowns were cemented using zinc phosphate cement, embedded in epoxy resin, and sectioned in two planes: diagonal and buccolingual. The crowns were then measured at nine sites. The results showed that there were no statistical differences between the external marginal opening of the titanium and the gold-platinum-palladium crowns. The overall marginal discrepancies for the restorations in this study were 61 microns (+/- 34 microns) for the titanium metal ceramic crowns and 47 microns (+/- 17 microns) for the gold-platinum-palladium metal ceramic crowns.

  8. Clinical utility of platinum chromium bare-metal stents in coronary heart disease

    Directory of Open Access Journals (Sweden)

    Jorge C

    2015-08-01

    Full Text Available Claudia Jorge,1 Christophe Dubois1,2 1Department of Cardiovascular Medicine, University Hospitals Leuven, 2Department of Cardiovascular Sciences, Katholieke Universiteit Leuven, Leuven, Belgium Abstract: Coronary stents represent a key development for the treatment of obstructive coronary artery disease since the introduction of percutaneous coronary intervention. While drug-eluting stents gained wide acceptance in contemporary percutaneous coronary intervention practice, further developments in bare-metal stents remain crucial for patients who are not candidates for drug-eluting stents, or to improve metallic platforms for drug elution. Initially, stent platforms used biologically inert stainless steel, restricting stent performance due to limitations in flexibility and strut thickness. Later, cobalt chromium stent alloys outperformed steel as the material of choice for stents, allowing latest generation stents to be designed with significantly thinner struts, while maintaining corrosion resistance and radial strength. Most recently, the introduction of the platinum chromium alloy refined stent architecture with thin struts, high radial strength, conformability, and improved radiopacity. This review will provide an overview of the novel platinum chromium bare-metal stent platforms available for coronary intervention. Mechanical properties, clinical utility, and device limitations will be summarized and put into perspective. Keywords: bare metal stent, coronary stent alloys, coronary artery disease

  9. Heterogeneous platinum-catalyzed hydrogenation of dialkyl(diolefin)platinum(II) complexes: A new route to platinum surface alkyls

    OpenAIRE

    McCarthy, Thomas J.; Shih, Yen-Shiang; Whitesides, George M.

    1981-01-01

    Platinum metal catalyzes the reduction of dialkyl(diolefin)platinum(II) complexes by dihydrogen to alkanes and platinum(0). The reaction involves adsorption of the platinum(II) complex on the platinum(0) catalyst surface with conversion of the alkyl moieties to platinum surface alkyls; these appear as alkane products. The platinum atom originally present in the soluble organoplatinum species becomes part of the platinum(0) surface.

  10. Experience in the Production of Horizontal Ingots of Platinum Metals and Alloys

    Institute of Scientific and Technical Information of China (English)

    LEVCHENKO S. D.; VERSHININA E. N.

    2012-01-01

    The quality of semi-products of platinum metals and alloys,produced by way of plastic working,essentially depends on or,in many cases,is completely determined by the quality of ingots.Plastic working does not make it possible to eliminate or localize metallurgical defects.In many cases it promotes the occurence thereof.Low-rate casting with directional crystallization can ensure the production of dense ingots free of non-metallic inclusions,shrinkage and gas weakness,with observance of certain temperature/rate modes.After comparative tests of vertical and horizontal molds,preference has been given to horizontal water-cooled molds,allowing to cast all alloys in the conditions of directional crystallization.

  11. Technology Development and Production of Certain Chemical Platinum Metals Compounds at JSC "Krastsvetmet"

    Institute of Scientific and Technical Information of China (English)

    ILYASHEVICH V.D.; PAVLOVA E.I.; KORITSKAYA N.G.; MAMONOV S.N.; SHULGIN D.R.; MALTSEV E.V.

    2012-01-01

    In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for industrial production of the following platinum metals compounds:- Rhodium (Ⅲ) chloride hydrate,rhodium (Ⅲ) chloride solution,rhodium ( Ⅲ) nitrate solution,rhodium ( Ⅲ)iodide,rhodium ( Ⅲ) sulfate,hydrated rhodium ( Ⅲ) oxide,ammonium hexachlororodiate,rhodium ( Ⅲ)phosphate solution,rhodium electrolytes;Iridium (Ⅳ) chloride hydrate,iridium (Ⅲ) chloride hydrate,ammonium hexachloroiridate (Ⅳ),hexachloriridium acid solution,hexachloriridium crystalline acid;- Ruthenium (Ⅲ) chloride hydrate,ruthenium (Ⅳ) hydroxide chloride,ruthenium (Ⅳ) hydroxide chloride solution,ammonium hexachlororuthenate,ruthenium (Ⅲ) chloride solution,potassium,diaquaoctachloronitrido diruthenate.The quality of the production meets the requirements of Russian and foreign consumers.

  12. Effects of interdigitated platinum finger geometry on spectral response characteristics of germanium metal-semiconductor-metal photodetectors.

    Science.gov (United States)

    Yang, Hyun-Duk; Janardhanam, V; Shim, Kyu-Hwan; Choi, Chel-Jong

    2014-10-01

    We fabricated interdigitated germanium (Ge) metal-semiconductor-metal photodetectors (MSM PDs) with interdigitated platinum (Pt) finger electrodes and investigated the effects of Pt finger width and spacing on their spectral response. An increase in the incident optical power enhances the creation of electron-hole pairs, resulting in a significant increase in photo current. Lowering of the Schottky barrier could be a main cause of the increase in both photo and dark current with increasing applied bias. The manufactured Ge MSM PDs exhibited a considerable spectral response for wavelengths in the range of 1.53-1.56 μm, corresponding to the entire C-band spectrum range. A reduction in the area fraction of the Pt finger electrode in the active region by decreasing and increasing finger width and spacing, respectively, led to an increase in illuminated active area and suppression of dark current, which was responsible for the improvement in responsivity and quantum efficiency of Ge MSM PDs.

  13. Global exploration and production capacity for platinum-group metals from 1995 through 2015

    Science.gov (United States)

    Wilburn, David R.

    2012-01-01

    Platinum-group metals (PGMs) are required in a variety of commercial, industrial, and military applications for many existing and emerging technologies, yet the United States is highly dependent on foreign sources of PGMs. Information on global exploration for PGMs since 1995 has been used in this study as a basis for identifying locations where the industry has determined that exploration has provided data sufficient to warrant development of a new mine or expansion of an existing operation or where a significant increase in capacity for PGMs is anticipated by 2015. Discussions include an overview of the industry and the selected sites, factors affecting mineral supply, and circumstances leading to the development of mineral properties with the potential to affect mineral supply. Of the 52 sites or regional operations that were considered in this analysis, 16 sites were producing before 1995, 28 sites commenced production from 1995 through 2010, and 8 sites were expected to begin production from 2011 through 2015 if development plans came to fruition. The United States imports PGMs primarily from Canada, Russia, South Africa, and Zimbabwe to meet increasing demand for these materials in a variety of specialized and high-tech applications. Feed sources of PGMs are changing in South Africa and Russia, which together accounted for about 89 percent of platinum production and 82 percent of palladium production in 2009. A greater amount of South African PGM capacity is likely to come from deeper, higher cost Upper Group Reef seam 2 deposits and deposits in the Eastern Bushveld area. Future Russian PGM capacity is likely to come from ore zones with generally lower PGM content and different platinum-to-palladium ratios than the nickel-rich ore that dominated PGM supply in the 1990s. Because PGM supply from Canada and Russia is derived as a byproduct of copper and nickel mining, the PGM supply from these countries is influenced by economic, environmental, political, and

  14. Global exploration and production capacity for platinum-group metals from 1995 through 2015

    Science.gov (United States)

    Wilburn, David R.

    2012-01-01

    Platinum-group metals (PGMs) are required in a variety of commercial, industrial, and military applications for many existing and emerging technologies, yet the United States is highly dependent on foreign sources of PGMs. Information on global exploration for PGMs since 1995 has been used in this study as a basis for identifying locations where the industry has determined that exploration has provided data sufficient to warrant development of a new mine or expansion of an existing operation or where a significant increase in capacity for PGMs is anticipated by 2015. Discussions include an overview of the industry and the selected sites, factors affecting mineral supply, and circumstances leading to the development of mineral properties with the potential to affect mineral supply. Of the 52 sites or regional operations that were considered in this analysis, 16 sites were producing before 1995, 28 sites commenced production from 1995 through 2010, and 8 sites were expected to begin production from 2011 through 2015 if development plans came to fruition. The United States imports PGMs primarily from Canada, Russia, South Africa, and Zimbabwe to meet increasing demand for these materials in a variety of specialized and high-tech applications. Feed sources of PGMs are changing in South Africa and Russia, which together accounted for about 89 percent of platinum production and 82 percent of palladium production in 2009. A greater amount of South African PGM capacity is likely to come from deeper, higher cost Upper Group Reef seam 2 deposits and deposits in the Eastern Bushveld area. Future Russian PGM capacity is likely to come from ore zones with generally lower PGM content and different platinum-to-palladium ratios than the nickel-rich ore that dominated PGM supply in the 1990s. Because PGM supply from Canada and Russia is derived as a byproduct of copper and nickel mining, the PGM supply from these countries is influenced by economic, environmental, political, and

  15. Development of Thin Film Ceramic Thermocouples for High Temperature Environments

    Science.gov (United States)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2004-01-01

    The maximum use temperature of noble metal thin film thermocouples of 1100 C (2000 F) may not be adequate for use on components in the increasingly harsh conditions of advanced aircraft and next generation launch technology. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically found in the form of rods or probes. NASA Glenn Research Center is investigating the feasibility of ceramics as thin film thermocouples for extremely high temperature applications to take advantage of the stability and robustness of ceramics and the non-intrusiveness of thin films. This paper will discuss the current state of development in this effort.

  16. Mapping the UV Photophysics of Platinum Metal Complexes Bound to Nucleobases

    Science.gov (United States)

    Sen, Ananya; Dessent, Caroline

    2015-03-01

    We report the first UV laser spectroscopic study of isolated gas-phase complexes of Platinum metal complex anions bound to a nucleobase as model systems for exploring at the molecular level the key photophysical processes involved in photodynamic therapy. Spectra of the PtIV CN 6 2 - • Uracil and PtII CN 4 2 - • Uracil complexes were acquired across the 220 -320 nm range using mass-selective photodepletion and photofragment action spectroscopy. The spectra of both complexes reveal prominent UV absorption bands that we assign primarily to excitation of the Uracil π - π * localized chromophore. Distinctive UV photofragments are observed for the complexes, with PtIV CN 6 2 - • Uracil photoexcitation resulting in complex fission, while PtII CN 4 2 - • Uracil photoexcitation initiates a nucleobase proton-transfer reaction across 4.4 -5.2 eV and electron detachment above 5.2 eV. The observed photofragments are consistent with ultrafast decay of a Uracil localized excited state back to the electronic ground state followed by intramolecular vibrational relaxation and ergodic complex fragmentation. In addition, we present recent results to explore how the photophysics of the Platinum complex-nucleobase clusters evolves as a function of nucleobase. Results are presented for PtII CN 4 2 - • Uracil complexed to Cytosine, Thymine and Adenine, reveal distinctive decay dynamics which we attribute to the intrinsic decay dynamics of the nucleobase. JPC. Lett. 2014, 5, 3281 to 3285 and PCCP 2014, 16, 15490 to 15500.

  17. Instrumentation System Diagnoses a Thermocouple

    Science.gov (United States)

    Perotti, Jose; Santiago, Josephine; Mata, Carlos; Vokrot, Peter; Zavala, Carlos; Burns, Bradley

    2008-01-01

    An improved self-validating thermocouple (SVT) instrumentation system not only acquires readings from a thermocouple but is also capable of detecting deterioration and a variety of discrete faults in the thermocouple and its lead wires. Prime examples of detectable discrete faults and deterioration include open- and short-circuit conditions and debonding of the thermocouple junction from the object, the temperature of which one seeks to measure. Debonding is the most common cause of errors in thermocouple measurements, but most prior SVT instrumentation systems have not been capable of detecting debonding. The improved SVT instrumentation system includes power circuitry, a cold-junction compensator, signal-conditioning circuitry, pulse-width-modulation (PWM) thermocouple-excitation circuitry, an analog-to-digital converter (ADC), a digital data processor, and a universal serial bus (USB) interface. The system can operate in any of the following three modes: temperature measurement, thermocouple validation, and bonding/debonding detection. The software running in the processor includes components that implement statistical algorithms to evaluate the state of the thermocouple and the instrumentation system. When the power is first turned on, the user can elect to start a diagnosis/ monitoring sequence, in which the PWM is used to estimate the characteristic times corresponding to the correct configuration. The user also has the option of using previous diagnostic values, which are stored in an electrically erasable, programmable read-only memory so that they are available every time the power is turned on.

  18. Platinum-coated non-noble metal-noble metal core-shell electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-14

    Core-shell particles encapsulated by a thin film of a catalytically active metal are described. The particles are preferably nanoparticles comprising a non-noble core with a noble metal shell which preferably do not include Pt. The non-noble metal-noble metal core-shell nanoparticles are encapsulated by a catalytically active metal which is preferably Pt. The core-shell nanoparticles are preferably formed by prolonged elevated-temperature annealing of nanoparticle alloys in an inert environment. This causes the noble metal component to surface segregate and form an atomically thin shell. The Pt overlayer is formed by a process involving the underpotential deposition of a monolayer of a non-noble metal followed by immersion in a solution comprising a Pt salt. A thin Pt layer forms via the galvanic displacement of non-noble surface atoms by more noble Pt atoms in the salt. The overall process is a robust and cost-efficient method for forming Pt-coated non-noble metal-noble metal core-shell nanoparticles.

  19. Cobra Probes Containing Replaceable Thermocouples

    Science.gov (United States)

    Jones, John; Redding, Adam

    2007-01-01

    A modification of the basic design of cobra probes provides for relatively easy replacement of broken thermocouples. Cobra probes are standard tube-type pressure probes that may also contain thermocouples and that are routinely used in wind tunnels and aeronautical hardware. They are so named because in side views, they resemble a cobra poised to attack. Heretofore, there has been no easy way to replace a broken thermocouple in a cobra probe: instead, it has been necessary to break the probe apart and then rebuild it, typically at a cost between $2,000 and $4,000 (2004 prices). The modified design makes it possible to replace the thermocouple, in minimal time and at relatively low cost, by inserting new thermocouple wire in a tube.

  20. High-temperature thermocouples and related methods

    Science.gov (United States)

    Rempe, Joy L.; Knudson, Darrell L.; Condie, Keith G.; Wilkins, S. Curt

    2011-01-18

    A high-temperature thermocouple and methods for fabricating a thermocouple capable of long-term operation in high-temperature, hostile environments without significant signal degradation or shortened thermocouple lifetime due to heat induced brittleness.

  1. Competitive platinum-group-metal (PGM) supply from the Eastern Limb, Bushveld Complex: Geological, mining and mineral economic aspects

    CSIR Research Space (South Africa)

    McGill, JE

    2011-08-01

    Full Text Available -GROUP-METAL (PGM) SUPPLY FROM THE EASTERN LIMB, BUSHVELD COMPLEX: GEOLOGICAL, MINING, AND MINERAL ECONOMIC ASPECTS Dr. Jeannette E. McGill & Prof. Murray W. Hitzman ACKNOWLEDGEMENTS ? COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH (CSIR) ? Centre for Mining... Innovation ? Office of Graduate Studies, Fogarty Endowment ? Mr. VISHNU PILLAY (EXECUTIVE HEAD: JV?S ? Anglo Platinum) ? ACADEMIC ADVISORS Prof. Murray Hitzman (Economic Geology); Dr. Hugh Miller (Mining Engineering); Prof. Rodderick Eggert (Mineral...

  2. Thermal Balance of the Magneto-Hydro-Dynamic Pump for Recovery of Platinum Group Metals from Spent Auto Catalysts

    Directory of Open Access Journals (Sweden)

    Gil S.

    2016-03-01

    Full Text Available Every new car should be equipped with the catalyst, which limits the amount of harmful chemical compounds such as NOx, CH and CO emitted to the air. Auto catalyst consists of the ceramic or metallic carrier, on which is the layer with Platinum Group Metals playing catalytic role. There are many methods using for recovery those valuable metals from spent auto catalyst, however evry of those methods have some limitations. Proces described in the article is the modified method of metal collector, which used magnetohydrodynamic pump. Rotary electromagnetic field generates in the liquid metal rotary current, which as a consequence washing out the PGM metals from the ceramic carriers. Considering the possibilities of commercialization of the described method, the energy balance was made. From that balance the energetic efficiency of the unit was determined and the analysis of the temperature distribution was shown thermographycally.

  3. Activity targets for nanostructured platinum-group-metal-free catalysts in hydroxide exchange membrane fuel cells

    Science.gov (United States)

    Setzler, Brian P.; Zhuang, Zhongbin; Wittkopf, Jarrid A.; Yan, Yushan

    2016-12-01

    Fuel cells are the zero-emission automotive power source that best preserves the advantages of gasoline automobiles: low upfront cost, long driving range and fast refuelling. To make fuel-cell cars a reality, the US Department of Energy has set a fuel cell system cost target of US$30 kW-1 in the long-term, which equates to US$2,400 per vehicle, excluding several major powertrain components (in comparison, a basic, but complete, internal combustion engine system costs approximately US$3,000). To date, most research for automotive applications has focused on proton exchange membrane fuel cells (PEMFCs), because these systems have demonstrated the highest power density. Recently, however, an alternative technology, hydroxide exchange membrane fuel cells (HEMFCs), has gained significant attention, because of the possibility to use stable platinum-group-metal-free catalysts, with inherent, long-term cost advantages. In this Perspective, we discuss the cost profile of PEMFCs and the advantages offered by HEMFCs. In particular, we discuss catalyst development needs for HEMFCs and set catalyst activity targets to achieve performance parity with state-of-the-art automotive PEMFCs. Meeting these targets requires careful optimization of nanostructures to pack high surface areas into a small volume, while maintaining high area-specific activity and favourable pore-transport properties.

  4. Activity targets for nanostructured platinum-group-metal-free catalysts in hydroxide exchange membrane fuel cells.

    Science.gov (United States)

    Setzler, Brian P; Zhuang, Zhongbin; Wittkopf, Jarrid A; Yan, Yushan

    2016-12-06

    Fuel cells are the zero-emission automotive power source that best preserves the advantages of gasoline automobiles: low upfront cost, long driving range and fast refuelling. To make fuel-cell cars a reality, the US Department of Energy has set a fuel cell system cost target of US$30 kW(-1) in the long-term, which equates to US$2,400 per vehicle, excluding several major powertrain components (in comparison, a basic, but complete, internal combustion engine system costs approximately US$3,000). To date, most research for automotive applications has focused on proton exchange membrane fuel cells (PEMFCs), because these systems have demonstrated the highest power density. Recently, however, an alternative technology, hydroxide exchange membrane fuel cells (HEMFCs), has gained significant attention, because of the possibility to use stable platinum-group-metal-free catalysts, with inherent, long-term cost advantages. In this Perspective, we discuss the cost profile of PEMFCs and the advantages offered by HEMFCs. In particular, we discuss catalyst development needs for HEMFCs and set catalyst activity targets to achieve performance parity with state-of-the-art automotive PEMFCs. Meeting these targets requires careful optimization of nanostructures to pack high surface areas into a small volume, while maintaining high area-specific activity and favourable pore-transport properties.

  5. Platinum-group elements in the Eastern Deccan volcanic province and a comparison with platinum metals of the western Deccan

    Indian Academy of Sciences (India)

    James Crocket; Dalim Paul; Trisha Lala

    2013-08-01

    This study is the first detailed investigation of the platinum-group elements (PGE) at the eastern margin of the Deccan volcanic province of India. One of the PGE, osmium, is not included largely because of analytical problems. The study is focused on mafic volcanics and dykes from four areas including Amarkantak, Umaria, Shahdol and Chirimiri. The first two localities represent two lava piles of about 170 and 400 m thickness respectively. In Umaria, 16 flows have been demarcated based on petrography and field studies. The Shahdol samples are basal lava formations overlying Gondwana sediments (Carboniferous) and the Chirimiri samples are dykes. In this study, the western Deccan province is defined as the Western Ghats plus Kutch. On average, the PGE are ∼20% higher in Amarkantak than Umaria and the flows are ∼13% higher in PGE than the dykes. A Zr vs. Pd scattergram found a strong positive correlation for these two elements except for one Umaria sample which indicated severe Pd loss. A comparison of west and east parts of the Deccan volcanic province using primitive mantle normalization showed that higher values prevailed in the western province suite in the Ni-Ir-Ru-Pt region. In contrast, eastern province values dominated in the Pd-Au-Cu region at the ‘Cu’ end of the profiles. A strong dominance of Pd in the eastern Deccan was also of interest. A number of factors, for example, percentage partial melting of the source rock and the temperature and pressure of partial melting strongly influence the character of these profiles. The observed PGE profile characteristics probably result in part from a long distance of subsurface transport of Deccan magma from the western to eastern regions.

  6. Simulation of a Shielded Thermocouple

    African Journals Online (AJOL)

    temperature in chemically, or mechanically, hostile environments. The sensitive ... the thermocouple is obtained by derivation of the heat propagation equation in cylindrical ..... equation (1.4) can be written as a system of of ordinary differential.

  7. First determination of the levels of platinum group metals in Manta birostris (manta ray) caught along the Ghanaian coastline.

    Science.gov (United States)

    Essumang, D K

    2010-06-01

    Tissues from Manta birostris caught by fishermen from Dixcove in the western part of Ghana were analyzed for their Platinum, palladium and rhodium concentrations (PGM). The use of chondrichthyan fish has permitted the study of trace levels of Platinum group metals (PGMs) which have travelled very far into the sea. The analysis showed that Ghana's coastline is fairly polluted with these platinum group metals (PGMs). PGM concentration in manta ray recorded a range of (0.15-0.85) microg/g for Pt, (0.033-0.67) microg/g for Pd and (0.007-0.145) microg/g for Rh. Comparing these values to the UK dietary intake of 0.2 microg/day for Pt and Rh and 1.0 microg/day for Pd, its indicates that the values obtained from the analysis for Pt was above the required level. This is the first study to show the accumulation of PGM in chondrichthyan fish, although the sources of this pollution are not clear as manta birostris is migratory and therefore need to be investigated further. The presence of the PGM is very significant, since manta ray meat is consumed in Ghana. This may presents a health risk, due to a possible accumulation of PGMs in humans.

  8. Material and Energy Flows Associated with Select Metals in GREET 2. Molybdenum, Platinum, Zinc, Nickel, Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Benavides, Pahola T. [Argonne National Lab. (ANL), Argonne, IL (United States); Dai, Qiang [Argonne National Lab. (ANL), Argonne, IL (United States); Sullivan, John L. [Argonne National Lab. (ANL), Argonne, IL (United States); Kelly, Jarod C. [Argonne National Lab. (ANL), Argonne, IL (United States); Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    In this work, we analyzed the material and energy consumption from mining to production of molybdenum, platinum, zinc, and nickel. We also analyzed the production of solar- and semiconductor-grade silicon. We described new additions to and expansions of the data in GREET 2. In some cases, we used operating permits and sustainability reports to estimate the material and energy flows for molybdenum, platinum, and nickel, while for zinc and silicon we relied on information provided in the literature.

  9. Behind platinum's sparkle.

    Science.gov (United States)

    Yam, Vivian W W

    2010-09-01

    As a rare and precious metal that is also resistant to wear and tarnish, platinum is known to be particularly well-suited to jewellery. Vivian Yam reflects on how, beyond its prestigious image, platinum has also found its way into a variety of fields ranging from the petrochemical to the pharmaceutical industry.

  10. Summary of thermocouple performance during advanced gas reactor fuel irradiation experiments in the advanced test reactor and out-of-pile thermocouple testing in support of such experiments

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, A. J.; Haggard, DC; Herter, J. W.; Swank, W. D.; Knudson, D. L.; Cherry, R. S. [Idaho National Laboratory, P.O. Box 1625, MS 4112, Idaho Falls, ID, (United States); Scervini, M. [University of Cambridge, Department of Material Science and Metallurgy, 27 Charles Babbage Road, CB3 0FS, Cambridge, (United Kingdom)

    2015-07-01

    High temperature gas reactor experiments create unique challenges for thermocouple-based temperature measurements. As a result of the interaction with neutrons, the thermoelements of the thermocouples undergo transmutation, which produces a time-dependent change in composition and, as a consequence, a time-dependent drift of the thermocouple signal. This drift is particularly severe for high temperature platinum-rhodium thermocouples (Types S, R, and B) and tungsten-rhenium thermocouples (Type C). For lower temperature applications, previous experiences with Type K thermocouples in nuclear reactors have shown that they are affected by neutron irradiation only to a limited extent. Similarly, Type N thermocouples are expected to be only slightly affected by neutron fluence. Currently, the use of these nickel-based thermocouples is limited when the temperature exceeds 1000 deg. C due to drift related to phenomena other than nuclear irradiation. High rates of open-circuit failure are also typical. Over the past 10 years, three long-term Advanced Gas Reactor experiments have been conducted with measured temperatures ranging from 700 deg. C - 1200 deg. C. A variety of standard Type N and specialty thermocouple designs have been used in these experiments with mixed results. A brief summary of thermocouple performance in these experiments is provided. Most recently, out-of-pile testing has been conducted on a variety of Type N thermocouple designs at the following (nominal) temperatures and durations: 1150 deg. C and 1200 deg. C for 2,000 hours at each temperature, followed by 200 hours at 1250 deg. C and 200 hours at 1300 deg. C. The standard Type N design utilizes high purity, crushed MgO insulation and an Inconel 600 sheath. Several variations on the standard Type N design were tested, including a Haynes 214 alloy sheath, spinel (MgAl{sub 2}O{sub 4}) insulation instead of MgO, a customized sheath developed at the University of Cambridge, and finally a loose assembly

  11. Summary of Thermocouple Performance During Advanced Gas Reactor Fuel Irradiation Experiments in the Advanced Test Reactor and Out-of-Pile Thermocouple Testing in Support of Such Experiments

    Energy Technology Data Exchange (ETDEWEB)

    A. J. Palmer; DC Haggard; J. W. Herter; M. Scervini; W. D. Swank; D. L. Knudson; R. S. Cherry

    2011-07-01

    High temperature gas reactor experiments create unique challenges for thermocouple based temperature measurements. As a result of the interaction with neutrons, the thermoelements of the thermocouples undergo transmutation, which produces a time dependent change in composition and, as a consequence, a time dependent drift of the thermocouple signal. This drift is particularly severe for high temperature platinum-rhodium thermocouples (Types S, R, and B); and tungsten-rhenium thermocouples (Types C and W). For lower temperature applications, previous experiences with type K thermocouples in nuclear reactors have shown that they are affected by neutron irradiation only to a limited extent. Similarly type N thermocouples are expected to be only slightly affected by neutron fluxes. Currently the use of these Nickel based thermocouples is limited when the temperature exceeds 1000°C due to drift related to phenomena other than nuclear irradiation. High rates of open-circuit failure are also typical. Over the past ten years, three long-term Advanced Gas Reactor (AGR) experiments have been conducted with measured temperatures ranging from 700oC – 1200oC. A variety of standard Type N and specialty thermocouple designs have been used in these experiments with mixed results. A brief summary of thermocouple performance in these experiments is provided. Most recently, out of pile testing has been conducted on a variety of Type N thermocouple designs at the following (nominal) temperatures and durations: 1150oC and 1200oC for 2000 hours at each temperature, followed by 200 hours at 1250oC, and 200 hours at 1300oC. The standard Type N design utilizes high purity crushed MgO insulation and an Inconel 600 sheath. Several variations on the standard Type N design were tested, including Haynes 214 alloy sheath, spinel (MgAl2O4) insulation instead of MgO, a customized sheath developed at the University of Cambridge, and finally a loose assembly thermocouple with hard fired alumina

  12. Calculating the melting curves by the thermodynamic data matching method: Platinum-group refractory metals (Ru, Os, and Ir)

    Science.gov (United States)

    Kulyamina, E. Yu.; Zitserman, V. Yu.; Fokin, L. R.

    2017-01-01

    A technique for reconstructing thermal properties, including the melting curve, of refractory metals based on the use of experimental data on caloric properties available up to the melting point and some regularities of the Debye-Grüneisen theory has been proposed. The calculation result is the consistent system of high-temperature thermal data, including the thermal expansion coefficient, solid-phase density, and volume jump upon melting. This technique was tried-out on refractory platinum-group metals based on experimental data on the enthalpy of the metals and confirmed by consistency with a thermodynamic calculation using shock-wave experiments and results obtained by the quantum molecular dynamics method.

  13. One-wire thermocouple

    Science.gov (United States)

    Goodrich, W. D.; Staimach, C. J.

    1977-01-01

    Nickel alloy/constantan device accurately measures surface temperature at precise locations. Device is moderate in cost and simplifies fabrication of highly-instrumented seamless-surface heat-transfer models. Device also applies to metal surfaces if constantan wire has insulative coat.

  14. Experimental partitioning of Zr, Ti, and Nb between silicate liquid and a complex noble metal alloy and the partitioning of Ti between perovskite and platinum metal

    Science.gov (United States)

    Jurewicz, Stephen R.; Jones, John H.

    1993-01-01

    El Goresy et al.'s observation of Nb, Zr, and Ta in refractory platinum metal nuggets (RPMN's) from Ca-Al-rich inclusions (CAI's) in the Allende meteorite led them to propose that these lithophile elements alloyed in the metallic state with noble metals in the early solar nebula. However, Grossman pointed out that the thermodynamic stability of Zr in the oxide phase is vastly greater than metallic Zr at estimated solar nebula conditions. Jones and Burnett suggested this discrepancy may be explained by the very non-ideal behavior of some lithophile transition elements in noble metal solutions and/or intermetallic compounds. Subsequently, Fegley and Kornacki used thermodynamic data taken from the literature to predict the stability of several of these intermetallic compounds at estimated solar nebula conditions. Palme and Schmitt and Treiman et al. conducted experiments to quantify the partitioning behavior of certain lithophile elements between silicate liquid and Pt-metal. Although their results were somewhat variable, they did suggest that Zr partition coefficients were too small to explain the observed 'percent' levels in some RPMN's. Palme and Schmitt also observed large partition coefficients for Nb and Ta. No intermetallic phases were identified. Following the work of Treiman et al., Jurewicz and Jones performed experiments to examine Zr, Nb, and Ti partitioning near solar nebula conditions. Their results showed that Zr, Nb, and Ti all have an affinity for the platinum metal, with Nb and Ti having a very strong preference for the metal. The intermetallic phases (Zr,Fe)Pt3, (Nb,Fe)Pt3, and (Ti,Fe)Pt3 were identified. Curiously, although both experiments and calculations indicate that Ti should partition strongly into Pt-metal (possibly as TiPt3), no Ti has ever been observed in any RPMN's. Fegley and Kornacki also noticed this discrepancy and hypothesized that the Ti was stabilized in perovskite which is a common phase in Allende CAI's.

  15. Investigation of Catalytic Finite-Size-Effects of Platinum Metal Clusters

    DEFF Research Database (Denmark)

    Li, Lin; Larsen, Ask Hjorth; Romero, Nichols A.

    2012-01-01

    In this paper, we use density functional theory (DFT) calculations on highly parallel computing resources to study size-dependent changes in the chemical and electronic properties of platinum (Pt) for a number of fixed freestanding clusters ranging from 13 to 1415 atoms, or 0.7–3.5 nm in diameter...

  16. Long range diffusion noise in platinum microwires with metallic adhesion layers

    NARCIS (Netherlands)

    Moktadir, Z.; van Honschoten, J.W.; Elwenspoek, Michael Curt

    2007-01-01

    Voltage fluctuations of platinum wires hosted by silicon nitride beams were investigated. The authors considered four variants of the wires: three with an adhesion layer and one without an adhesion layer. They found that the presence of an adhesion layer changes the nature of the power spectrum

  17. Thermoelectric properties of currently available Au/Pt thermocouples related to the valid reference function

    Directory of Open Access Journals (Sweden)

    Edler F.

    2015-01-01

    Full Text Available Au/Pt thermocouples are considered to be an alternative to High Temperature Standard Platinum Resistance Thermometers (HTSPRTs for realizing temperatures according to the International Temperature Scale of 1990 (ITS-90 in the temperature range between aluminium (660.323 °C and silver (961.78 °C. The original aim of this work was to develop and to validate a new reference function for Au/Pt thermocouples which reflects the properties of presently commercially available Au and Pt wires. The thermoelectric properties of 16 Au/Pt thermocouples constructed at different National Metrological Institutes by using wires from different suppliers and 4 commercially available Au/Pt thermocouples were investigated. Most of them exhibit significant deviations from the current reference function of Au/Pt thermocouples caused by the poor performance of the Au-wires available. Thermoelectric homogeneity was investigated by measuring immersion profiles during freezes at the freezing point of silver and in liquid baths. The thermoelectric inhomogeneities were found to be one order of magnitude larger than those of Au/Pt thermocouples of the Standard Reference Material® (SRM® 1749. The improvement of the annealing procedure of the gold wires is a key process to achieve thermoelectric homogeneities in the order of only about (2–3 mK, sufficient to replace the impracticable HTSPRTs as interpolation instruments of the ITS-90. Comparison measurements of some of the Au/Pt thermocouples against a HTSPRT and an absolutely calibrated radiation thermometer were performed and exhibit agreements within the expanded measurement uncertainties. It has been found that the current reference function of Au/Pt thermocouples reflects adequately the thermoelectric properties of currently available Au/Pt thermocouples.

  18. Unprecedented 1D Mixed-metal Polynuclear Cyclometalated Platinum Complexes: Synthesis,Structural Characterization and Spectroscopic Properties

    Institute of Scientific and Technical Information of China (English)

    CAO Qian-Yong; GAN Xin; ZHANG Jun-Feng; CHI Shao-Ming; LI Hui-Fangjie; FU Wen-Fu

    2007-01-01

    The complexes [Pt2L2(μ-dppm)](ClO4)2.(1) and {[Pt2L2(μ-dppm)Li(CH3CN)2](ClO4)3}n (2),where HL is 6-[4-(diethoxyphosphorylmethyl)phenyl]-2,2'-bipyridinyl and dppm is bis(diphenylphosphino)methane,have been synthesized and characterized.In complex 1 the platinum(Ⅱ) center adopts a distorted square planar coordination geometry.The polymer 2 exhibits a "stairstep" configuration with one-dimensional Pt(Ⅱ)N^N^CPO- Li(Ⅰ)-OPC^N^NPt(Ⅱ) mixed-metal units which are linked through dppm.Both complexes have metal-metal interaction with PtPt distances of 3.325(2) and 3.1432(9) (A),respectively,and display strong metal-metal-to-ligand charge-transfer (MMLCT) triplet state emission.The density-functional-theory calculation was used to interpret the absorption spectra of the complexes.

  19. Oxidizing behavior of some platinum metal fluorides. [Xe complexes with Pt, Pd fluorides; Chlorine-2 oxidation by transition metal hexafluorides

    Energy Technology Data Exchange (ETDEWEB)

    Graham, L.

    1978-10-01

    The previously known compounds Xe/sub 2/F/sub 3//sup +/PtF/sub 6//sup -/, XeF/sup +/PtF/sub 6//sup -/ and XeF/sub 2/.2PtF/sub 4/(XePt/sub 2/F/sub 10/) were prepared by the interaction of XeF/sub 2/ with PtF/sub 4/. The new compounds XeF/sub 2/.PdF/sub 4/ and XeF/sub 2/.2PdF/sub 4/(XePd/sub 2/F/sub 10/) were produced by interaction of XeF/sub 2/ with either PdF/sub 4/ or Pd/sub 2/F/sub 6/. A weight loss-versus-time curve indicated the presence of 4:1, 3:1 and 2:1 XeF/sub 2//PdF/sub 4/ complexes. The thermal decomposition of XeFPtF/sub 6/ or XePd/sub 2/F/sub 10/ yields highly pure XeF/sub 4/. Thus the interaction of XeF/sub 2/ with platinum fluorides (PtF/sub 4/ or PtF/sub 5/) or palladium fluorides (Pd/sub 2/F/sub 6/ or PdF/sub 4/) provides for the conversion of XeF/sub 2/ to XeF/sub 4/. The compound XePd/sub 2/F/sub 10/ is a close structural relative of XePt/sub 2/F/sub 10/, and spectroscopic evidence suggests that both are salts of XeF/sup +/ and a polymeric (M/sub 2/F/sub 9/)/sub x//sup x-/ ion. A Xe:PtF/sub 6/ material of approximately 1:1 stoichiometry has been prepared and compared with XePdF/sub 6/(XeF/sub 2/.PdF/sub 4/). The interaction of chlorine with the third-series transition metal hexafluorides has been investigated. Gravimetric and tensimetric evidence indicate that the initial product of the Cl/sub 2/ plus IrF/sub 6/ reaction is a solid of composition Cl/sub 2/IrF/sub 6/. Vibrational spectroscopic and other evidence indicates that this solid yields a sequence of products, of which Cl/sub 3//sup +/IrF/sub 6//sup -/, Cl/sub 3//sup +/Ir/sub 2/F/sub 11//sup -/ and Ir/sub 4/F/sub 20/ have been identified, the last being the ultimate solid product of the room temperature decomposition of the adduct. A new chlorine fluoride generated in the room temperature decomposition of Cl/sub 2/IrF/sub 6/ has been tentatively formulated as Cl/sub 3/F from infrared evidence.

  20. Binding of kinetically inert metal ions to RNA: the case of platinum(II).

    Science.gov (United States)

    Chapman, Erich G; Hostetter, Alethia A; Osborn, Maire F; Miller, Amanda L; DeRose, Victoria J

    2011-01-01

    In this chapter several aspects of Pt(II) are highlighted that focus on the properties of Pt(II)-RNA adducts and the possibility that they influence RNA-based processes in cells. Cellular distribution of Pt(II) complexes results in significant platination of RNA, and localization studies find Pt(II) in the nucleus, nucleolus, and a distribution of other sites in cells. Treatment with Pt(II) compounds disrupts RNA-based processes including enzymatic processing, splicing, and translation, and this disruption may be indicative of structural changes to RNA or RNA-protein complexes. Several RNA-Pt(II) adducts have been characterized in vitro by biochemical and other methods. Evidence for Pt(II) binding in non-helical regions and for Pt(II) cross-linking of internal loops has been found. Although platinated sites have been identified, there currently exists very little in the way of detailed structural characterization of RNA-Pt(II) adducts. Some insight into the details of Pt(II) coordination to RNA, especially RNA helices, can be gained from DNA model systems. Many RNA structures, however, contain complex tertiary folds and common, purine-rich structural elements that present suitable Pt(II) nucleophiles in unique arrangements which may hold the potential for novel types of platinum-RNA adducts. Future research aimed at structural characterization of platinum-RNA adducts may provide further insights into platinum-nucleic acid binding motifs, and perhaps provide a rationale for the observed inhibition by Pt(II) complexes of splicing, translation, and enzymatic processing.

  1. Contamination from gold and platinum-group metals mining in the Gulf of Darién, Colombia

    Science.gov (United States)

    Vasquez-Bedoya, L.; Palacio Baena, J.

    2013-12-01

    Gulf of Darién, triangular southernmost extension of the Caribbean Sea, bounded by Panama on the southwest and by Colombia on the southeast and east. The Gulf is made up of 17 municipalities in the department of Choco and Antioquia. The Gulf of Darién is a geostrategic region, rich in biodiversity, known for its natural resources of minerals, oil, lumber as well as its water and fertile land. The Darién also acts as the bridge between South America and Central America and has access to the Pacific Ocean and the Caribbean Sea. The economy in the region is based mainly on agribusinesses, tourism and mining activities, mainly the 'mining of gold and platinum-group metals'. In our study we determined the degree of trace element contamination in estuarine sediment samples originated from mining activities and municipal waste water discharges of effluents on the gulf of Darién. . Surface samples were taken from 17 locations through the entire Gulf. Grain size, Corg, Ag, Al, Ca , Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb and Zn concentrations were analyzed, and enrichment factors (EF) as well as geo-accumulation indices (Igeo) were calculated. Concentrations of Pb, Zn, Ni, Cu and Cr show levels that are consistent with those typically found in urbanized marine environments. EF and Igeo values revealed that the Gulf is extremely contaminated with Ag and moderately contaminated with Cr and Zn. The sources of Cr, Ag, Hg and Zn are associated with the development of mining activities in the Atrato River basin. The observed enrichment of Ag may be explained as a residue of the extraction of gold and platinum-group metals.

  2. Heat production in microwave-irradiated thermocouples.

    Science.gov (United States)

    Dunscombe, P B; McLellan, J; Malaker, K

    1986-01-01

    It has been known for some time that the irradiation of metallic thermometers by microwaves during clinical hyperthermia can lead to artifactual readings. We describe here a series of measurements in which this effect has been quantitatively studied. In particular, the data yield values for the conversion coefficient describing the rate of heat production per unit length of a thermocouple array per watt applied power which can be compared with the rate of heat production in the same volume of tissue. The degree of artifact in the temperature recording depends on the thermal resistance of the protective materials surrounding the array, and this thermal resistance has also been determined. It has been shown that measures taken to reduce the temperature artifact do not compromise the response time of the probe.

  3. Electrodeposited submicron thermocouples with microsecond response times.

    Science.gov (United States)

    Bourg, M E; van der Veer, W E; Güell, A G; Grüell, A G; Penner, R M

    2007-10-01

    We describe a procedure for preparing submicron scale silver-nickel thermocouples (TCs) using electrochemical step edge decoration on graphite surfaces. Each fabrication operation produced ensembles of 2-20 TCs with diameters in the 1.0 microm to 500 nm range. These "sub-mum TCs" (SMTCs) produced linear voltage versus temperature output over the range from 20 to 100 degrees C characterized by a Seebeck coefficient of 20 +/- 1 microV/degrees C, equal to the 21 microV/degrees C that is theoretically expected for a junction between these two metals. The time response of SMTCs was evaluated using two different laser-heating methods and compared with the smallest mechanically robust commercially available type J TCs. Electrochemical etching of the silver wire introduced constrictions at grain boundaries that reduced the thermal mass of the junction without altering its integrity or its overall diameter, producing a decrease of the measured rise time for SMTCs up to 96%.

  4. Material Problems in Using High-Temperature Thermocouples

    Science.gov (United States)

    Edler, F.

    2011-08-01

    The material compatibility and thermal stability of ceramic-composite coatings of different oxide ceramics deposited on alumina tubes to prevent the reduction of the alumina were investigated in the high-temperature range between 1750 °C and 1850 °C. It turned out that the coatings were thermally unstable and did not provide adequate protection against the reduction of the alumina tubes. The oxide ceramics formed eutectic compositions with low melting temperatures and were also prone to reduction to elementary metals by carbon. A new type of high-temperature thermocouple on the basis of refractory and noble metals was tested in the temperature range between 1325 °C and 1800 °C. Two metal-sheathed prototypes were constructed. The thermoelectric behavior of the tungsten5%rhenium/iridium thermocouples (W5%Re/Ir) was investigated by different high-temperature exposures, and the thermoelectric stability was checked by repeated measurements at the ice point.

  5. Formation of {open_quotes}metal wool{close_quotes} structures and dynamics of catalytic etching of platinum surfaces during ammonia oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Lyubovsky, M.R.; Barelko, V.V. [Institute of Chemical Physics in Chernogolovka, Moscow (Russian Federation)

    1994-09-01

    Reconstruction of a clean surface of a platinum catalyst and a platinum surface covered with gold during ammonia oxidation was studied by SEM observations. It was found that the process of catalytic etching had two sequential stages in which different crystal structures with different rates of growth formed on the surface. The first stage was the formation of parallel facets, and the second stage was the formation of individual microcrystals with perfect crystal faces. It was also found that the second state had a threshold character, beginning after some delay from the start of the reaction. A structure resembling metal wool and consisting of interlaced platinum filaments was found to form on the surface of gold-covered platinum catalysts. Characteristic features of this structure`s development are reported. The growth of filaments is attributed to the vapor-liquid-solid mechanism of whisker growth. On the basis of the observed platinum whisker formation and behavior during ammonia oxidation, a mechanism of catalyst surface reconstruction that explains observed characteristic features of the process of catalytic etching is proposed. 25 refs., 8 figs.

  6. Kinetics and mechanism for reversible chloride transfer between mercury(II) and square-planar platinum(II) chloro ammine, aqua, and sulfoxide complexes. Stabilities, spectra, and reactivities of transient metal-metal bonded platinum-mercury adducts.

    Science.gov (United States)

    Gröning, O; Sargeson, A M; Deeth, R J; Elding, L I

    2000-09-18

    The Hg2+aq- and HgCl+aq-assisted aquations of [PtCl4]2- (1), [PtCl3(H2O)]- (2), cis-[PtCl2(H2O)2] (3), trans-[PtCl2(H2O)2] (4), [PtCl(H2O)3]+ (5), [PtCl3Me2SO]- (6), trans-[PtCl2(H2O)Me2SO] (7), cis-[PtCl(H2O)2Me2SO]+ (8), trans-[PtCl(H2O)2M32SO]+ (9), trans-[PtCl2(NH3)2] (10), and cis-[PtCl2(NH3)2] (11) have been studied at 25.0 degrees C in a 1.00 M HClO4 medium buffered with chloride, using stopped-flow and conventional spectrophotometry. Saturation kinetics and instantaneous, large UV/vis spectral changes on mixing solutions of platinum complex and mercury are ascribed to formation of transient adducts between Hg2+ and several of the platinum complexes. Depending on the limiting rate constants, these adducts are observed for a few milliseconds to a few minutes. Thermodynamic and kinetics data together with the UV/vis spectral changes and DFT calculations indicate that their structures are characterized by axial coordination of Hg to Pt with remarkably short metal-metal bonds. Stability constants for the Hg2+ adducts with complexes 1-6, 10, and 11 are (2.1 +/- 0.4) x 10(4), (8 +/- 1) x 10(2), 94 +/- 6, 13 +/- 2, 5 +/- 2, 60 +/- 6, 387 +/- 2, and 190 +/- 3 M-1, respectively, whereas adduct formation with the sulfoxide complexes 7-9 is too weak to be observed. For analogous platinum(II) complexes, the stabilities of the Pt-Hg adducts increase in the order sulfoxide < aqua < ammine complex, reflecting a sensitivity to the pi-acid strength of the Pt ligands. Rate constants for chloride transfer from HgCl+ and HgCl2 to complexes 1-11 have been determined. Second-order rate constants for activation by Hg2+ are practically the same as those for activation by HgCl+ for each of the platinum complexes studied, yet resolved contributions for Hg2+ and HgCl+ reveal that the latter does not form dinuclear adducts of any significant stability. The overall experimental evidence is consistent with a mechanism in which the accumulated Pt(II)-Hg2+ adducts are not reactive

  7. Determination of hydrogen permeation using metallic sensors of construction similar to bimetallic thermocouples; Determinacao de permeacao de hidrogenio utilizando sensores metalicos de construcao similar a termopares bimetalicos

    Energy Technology Data Exchange (ETDEWEB)

    Maul, Alexandre M. [Ministerio de Ciencia e Tecnologia (MCT), Brasilia, DF (Brazil). Programa de Pos-graduacao em Engenharia e Processos (PIPE- PRH-24/ANP); Ponte, Haroldo A. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Correa, Luiz A. [Metaldata Tecnologia de Materiais, Curitiba, PR (Brazil)] (in Memoriam)

    2004-07-01

    Crude oils range in consistency from water to tar-like solids, and in color from clear to black. An average crude oil contains about 84 percent carbon, 14 percent hydrogen, 1 to 3 percent sulfur, and less than 1 percent each of nitrogen, oxygen, metals, and salts. Crude oils are generally classified as paraffinic, naphthenic, or aromatic based on the predominant proportion of similar hydrocarbon molecules. Refinery crude base stocks usually consist of mixtures of two or more different crude oils. Many corrosive processes found in machines, equipment and pipes used in the petroleum industry are directly influenced by hydrogen. The structural damages are caused by hydrogen inclusion in metallic structures, generated by acid media that contain free protons (H{sup +}), by chemical processes that lead to the protons formation, by formation of atomic hydrogen (H0) or even by adsorbed gas hydrogen (H2). The structural damages are varied: hydrogen induced cracking (HIC), blistering, stress corrosion cracking (SSC), stress oriented hydrogen induced cracking (SOHIC). The main problem found in practice is how to detect, in a safe, fast and economically viable way, the formation of hydrogen close to a surface subjected to hydrogen permeation. Within this work, we built a cell for hydrogen generation/permeation to study and evaluate a new hydrogen sensor. This new sensor is composed of two parts, each one build with a couple of dissimilar materials, being a sensor couple, for hydrogen flux measurement, and a reference couple, for temperature corrections. In this sensor, the changes in some physical properties are related with the flow of permeated hydrogen. The results using a prototype model showed good agreement with a traditional Devanathan-Stachurski sensor. (author)

  8. Determination of hydrogen permeation using metallic sensors of construction similar to bimetallic thermocouples; Determinacao de permeacao de hidrogenio utilizando sensores metalicos de construcao similar a termopares bimetalicos

    Energy Technology Data Exchange (ETDEWEB)

    Maul, Alexandre M. [Ministerio de Ciencia e Tecnologia (MCT), Brasilia, DF (Brazil). Programa de Pos-graduacao em Engenharia e Processos (PIPE- PRH-24/ANP); Ponte, Haroldo A. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Correa, Luiz A. [Metaldata Tecnologia de Materiais, Curitiba, PR (Brazil)] (in Memoriam)

    2004-07-01

    Crude oils range in consistency from water to tar-like solids, and in color from clear to black. An average crude oil contains about 84 percent carbon, 14 percent hydrogen, 1 to 3 percent sulfur, and less than 1 percent each of nitrogen, oxygen, metals, and salts. Crude oils are generally classified as paraffinic, naphthenic, or aromatic based on the predominant proportion of similar hydrocarbon molecules. Refinery crude base stocks usually consist of mixtures of two or more different crude oils. Many corrosive processes found in machines, equipment and pipes used in the petroleum industry are directly influenced by hydrogen. The structural damages are caused by hydrogen inclusion in metallic structures, generated by acid media that contain free protons (H{sup +}), by chemical processes that lead to the protons formation, by formation of atomic hydrogen (H0) or even by adsorbed gas hydrogen (H2). The structural damages are varied: hydrogen induced cracking (HIC), blistering, stress corrosion cracking (SSC), stress oriented hydrogen induced cracking (SOHIC). The main problem found in practice is how to detect, in a safe, fast and economically viable way, the formation of hydrogen close to a surface subjected to hydrogen permeation. Within this work, we built a cell for hydrogen generation/permeation to study and evaluate a new hydrogen sensor. This new sensor is composed of two parts, each one build with a couple of dissimilar materials, being a sensor couple, for hydrogen flux measurement, and a reference couple, for temperature corrections. In this sensor, the changes in some physical properties are related with the flow of permeated hydrogen. The results using a prototype model showed good agreement with a traditional Devanathan-Stachurski sensor. (author)

  9. Thermocouple Rakes for Measuring Boundary Layer Flows Extremely Close to Surface

    Science.gov (United States)

    Hwang, Danny P.; Fralick, Gustave C.; Martin, Lisa C.; Blaha, Charles A.

    2001-01-01

    Of vital interest to aerodynamic researchers is precise knowledge of the flow velocity profile next to the surface. This information is needed for turbulence model development and the calculation of viscous shear force. Though many instruments can determine the flow velocity profile near the surface, none of them can make measurements closer than approximately 0.01 in. from the surface. The thermocouple boundary-layer rake can measure much closer to the surface than conventional instruments can, such as a total pressure boundary layer rake, hot wire, or hot film. By embedding the sensors (thermocouples) in the region where the velocity is equivalent to the velocity ahead of a constant thickness strut, the boundary-layer flow profile can be obtained. The present device fabricated at the NASA Glenn Research Center microsystem clean room has a heater made of platinum and thermocouples made of platinum and gold. Equal numbers of thermocouples are placed both upstream and downstream of the heater, so that the voltage generated by each pair at the same distance from the surface is indicative of the difference in temperature between the upstream and downstream thermocouple locations. This voltage differential is a function of the flow velocity, and like the conventional total pressure rake, it can provide the velocity profile. In order to measure flow extremely close to the surface, the strut is made of fused quartz with extremely low heat conductivity. A large size thermocouple boundary layer rake is shown in the following photo. The latest medium size sensors already provide smooth velocity profiles well into the boundary layer, as close as 0.0025 in. from the surface. This is about 4 times closer to the surface than the previously used total pressure rakes. This device also has the advantage of providing the flow profile of separated flow and also it is possible to measure simultaneous turbulence levels within the boundary layer.

  10. Thermocouple Structure in Thermoelectric Conversion Devices

    Institute of Scientific and Technical Information of China (English)

    WU; Wei-ming; TANG; Xian; LUO; Zhi-fu

    2013-01-01

    The core of thermoelectric conversion device is the thermocouples which are constituted with P-type and N-type thermoelectric material.Thermocouple structure is very important for efficiency of thermoelectric power generation.Common thermocouple is the segmented structure,as shown in Fig.1.Each material works in its best temperature range.This structure ensures that the device get a high figure

  11. Thermal Preconditioning of MIMS Type K Thermocouples to Reduce Drift

    Science.gov (United States)

    Webster, E. S.

    2017-01-01

    Type K thermocouples are the most widely used temperature sensors in industry and are often used in the convenient mineral-insulated metal-sheathed (MIMS) format. The MIMS format provides almost total immunity to oxide-related drift in the 800°C-1000°C range. However, crystalline ordering of the atomic structure causes drift in the range 200°C-600°C. Troublesomely, the effects of this ordering are reversible, leading to hysteresis in some applications. Typically, MIMS cable is subjected to a post-manufacturing high-temperature recrystallization anneal to remove cold-work and place the thermocouple in a `known state.' However, variations in the temperatures and times of these exposures can lead to variations in the `as-received state.' This study gives guidelines on the best thermal preconditioning of 3 mm MIMS Type K thermocouples in order to minimize drift and achieve the most reproducible temperature measurements. Experimental results demonstrate the consequences of using Type K MIMS thermocouples in different states, including the as-received state, after a high-temperature recrystallization anneal and after preconditioning anneals at 200°C, 300°, 400°C and and 500°C. It is also shown that meaningful calibration is possible with the use of regular preconditioning anneals.

  12. Assessing Economic Modulation of Future Critical Materials Use: The Case of Automotive-Related Platinum Group Metals.

    Science.gov (United States)

    Zhang, Jingshu; Everson, Mark P; Wallington, Timothy J; Field, Frank R; Roth, Richard; Kirchain, Randolph E

    2016-07-19

    Platinum-group metals (PGMs) are technological and economic enablers of many industrial processes. This important role, coupled with their limited geographic availability, has led to PGMs being labeled as "critical materials". Studies of future PGM flows have focused on trends within material flows or macroeconomic indicators. We complement the previous work by introducing a novel technoeconomic model of substitution among PGMs within the automotive sector (the largest user of PGMs) reflecting the rational response of firms to changing prices. The results from the model support previous conclusions that PGM use is likely to grow, in some cases strongly, by 2030 (approximately 45% for Pd and 5% for Pt), driven by the increasing sales of automobiles. The model also indicates that PGM-demand growth will be significantly influenced by the future Pt-to-Pd price ratio, with swings of Pt and Pd demand of as much as 25% if the future price ratio shifts higher or lower even if it stays within the historic range. Fortunately, automotive catalysts are one of the more effectively recycled metals. As such, with proper policy support, recycling can serve to meet some of this growing demand.

  13. Inorganic nanocarriers for platinum drug delivery

    Directory of Open Access Journals (Sweden)

    Ping’an Ma

    2015-12-01

    Full Text Available Nowadays platinum drugs take up almost 50% of all the clinically used anticancer drugs. Besides cisplatin, novel platinum agents including sterically hindered platinum (II drugs, chemically reductive platinum (IV drugs, photosensitive platinum (IV drugs, and multinuclear platinum drugs have been developed recently, with a few entering clinic trials. Rapid development of nanobiotechnology makes targeted delivery of anticancer platinum agents to the tumor site possible, while simultaneously minimizing toxicity and maximizing the drug efficacy. Being versatile drug carriers to deliver platinum drugs, inorganic nanovehicles such as gold nanoparticles, iron oxide nanomaterials, carbon nanotubes, mesoporous nanosilica, metal-organic frameworks (MOFs, have been extensively studied over the past decades. In contrast to conventional polymeric and lipid nanoparticles, inorganic nanoparticles based drug carriers are peculiar as they have shown excellent theranostic effects, revealing themselves an indispensable part of future nanomedicine. Here, we will elaborate recent research advances on fabrication of inorganic nanoparticles for platinum drug delivery.

  14. Platinum nitride with fluorite structure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rong; Zhang, Xiao-Feng

    2005-01-31

    The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.

  15. The transient response for different types of erodable surface thermocouples using finite element analysis

    Directory of Open Access Journals (Sweden)

    Mohammed Hussein

    2007-01-01

    Full Text Available The transient response of erodable surface thermocouples has been numerically assessed by using a two dimensional finite element analysis. Four types of base metal erodable surface thermocouples have been examined in this study, included type-K (alumel-chromel, type-E (chromel-constantan, type-T (copper-constantan, and type-J (iron-constantan with 50 mm thick- ness for each. The practical importance of these types of thermocouples is to be used in internal combustion engine studies and aerodynamics experiments. The step heat flux was applied at the surface of the thermocouple model. The heat flux from the measurements of the surface temperature can be commonly identified by assuming that the heat transfer within these devices is one-dimensional. The surface temperature histories at different positions along the thermocouple are presented. The normalized surface temperature histories at the center of the thermocouple for different types at different response time are also depicted. The thermocouple response to different heat flux variations were considered by using a square heat flux with 2 ms width, a sinusoidal surface heat flux variation width 10 ms period and repeated heat flux variation with 2 ms width. The present results demonstrate that the two dimensional transient heat conduction effects have a significant influence on the surface temperature history measurements made with these devices. It was observed that the surface temperature history and the transient response for thermocouple type-E are higher than that for other types due to the thermal properties of this thermocouple. It was concluded that the thermal properties of the surrounding material do have an impact, but the properties of the thermocouple and the insulation materials also make an important contribution to the net response.

  16. Batch leaching tests of motherboards to assess environmental contamination by bromine, platinum group elements and other selected heavy metals.

    Science.gov (United States)

    Almeida, César; Grosselli, Melina; González, Patricia; Martínez, Dante; Gil, Raúl

    2016-02-01

    In this study, a batch leaching test was executed to evaluate the toxicity associated with chemicals contained in motherboards. The leaching solutions used were distilled water, nitric acid, acetic acid and synthetic acid rain solution. A total of 21 elements including Ag, As, Au, Br, Cd, Co, Cr, Cu, Hf, Ir, Mn, Ni, Os, Pb, Pd, Pt, Rd, Rh, Se, U and Zn were analyzed. In this study, the pH values of all the leachates fell within the range of 2.33-4.88. The highest concentrations of metals were obtained from the acid rain solution, whilst the maximum value of bromine was achieved with solution of acetic acid. Appreciable concentrations of platinum group elements were detected with concentrations around 3.45, 1.43, 1.21 and 22.19 µg L(-1) for Ir, Pd, Pt and Rh, respectively. The different leaching of the motherboards revealed the predominant presence of the toxic substances in the leached from the e-waste.

  17. AGR-1 Thermocouple Data Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jeff Einerson

    2012-05-01

    This report documents an effort to analyze measured and simulated data obtained in the Advanced Gas Reactor (AGR) fuel irradiation test program conducted in the INL's Advanced Test Reactor (ATR) to support the Next Generation Nuclear Plant (NGNP) R&D program. The work follows up on a previous study (Pham and Einerson, 2010), in which statistical analysis methods were applied for AGR-1 thermocouple data qualification. The present work exercises the idea that, while recognizing uncertainties inherent in physics and thermal simulations of the AGR-1 test, results of the numerical simulations can be used in combination with the statistical analysis methods to further improve qualification of measured data. Additionally, the combined analysis of measured and simulation data can generate insights about simulation model uncertainty that can be useful for model improvement. This report also describes an experimental control procedure to maintain fuel target temperature in the future AGR tests using regression relationships that include simulation results. The report is organized into four chapters. Chapter 1 introduces the AGR Fuel Development and Qualification program, AGR-1 test configuration and test procedure, overview of AGR-1 measured data, and overview of physics and thermal simulation, including modeling assumptions and uncertainties. A brief summary of statistical analysis methods developed in (Pham and Einerson 2010) for AGR-1 measured data qualification within NGNP Data Management and Analysis System (NDMAS) is also included for completeness. Chapters 2-3 describe and discuss cases, in which the combined use of experimental and simulation data is realized. A set of issues associated with measurement and modeling uncertainties resulted from the combined analysis are identified. This includes demonstration that such a combined analysis led to important insights for reducing uncertainty in presentation of AGR-1 measured data (Chapter 2) and interpretation of

  18. Measurement of Inhomogeneities in MIMS Thermocouples Using a Linear-Gradient Furnace and Dual Heat-Pipe Scanner

    Science.gov (United States)

    Webster, E. S.; White, D. R.; Edgar, H.

    2015-03-01

    This paper describes a linear-gradient furnace and a thermocouple homogeneity scanner that, together, measure changes in the Seebeck coefficient as a function of time and temperature. The furnace first exposes the test thermocouple to all temperatures in the range spanned by the furnace gradient. The homogeneity scanner then measures the Seebeck coefficient along the length of the thermocouple. By correlating the position on the thermocouple with the temperature in the furnace, changes in the Seebeck coefficient can be correlated with the temperature to which that part of the thermocouple was exposed. Repeat exposures for different durations allow the rapid accumulation of data describing drift versus temperature and time. The known profile of the furnace combined with the high resolution of the dual heat-pipe scanner enable the detection of Seebeck coefficient changes of less than 0.02 % over sub-millimeter distances. The high resolution of the scanner also minimizes the underestimation of short-range changes in the Seebeck coefficient. With the addition of other treatment processes, such as annealing, quenching, and cold work, the system can assess the full variety of reversible and irreversible effects in thermocouples. Preliminary experiments on base-metal thermocouples confirm much of the known long-term behavior. However, the system has also exposed the rapid onset of some of these effects at low temperatures, the large amount and variability of cold work in new thermocouples, and large variations between different thermocouples of the same type.

  19. Request for Correction 11001 Toxicological Review of Halogenated Platinum Salts and Platinum Compounds

    Science.gov (United States)

    Request for Correction by the International Platinum Group Metals Association seeking the correction of information disseminated in the draft EPA document Toxicological Review of Halogenated Platinum Salts and Platinum Compounds: In Support of Summary Information on the Integrated Risk Information System (IRIS).

  20. Synthesis of Platinum Nanotubes and Nanorings via Simultaneous Metal Alloying and Etching

    KAUST Repository

    Huang, Zhiqi

    2016-04-19

    Metallic nanotubes represent a class of hollow nanostructures with unique catalytic properties. However, the wet-chemical synthesis of metallic nanotubes remains a substantial challenge, especially for those with dimensions below 50 nm. This communication describes a simultaneous alloying-etching strategy for the synthesis of Pt nanotubes with open ends by selective etching Au core from coaxial Au/Pt nanorods. This approach can be extended for the preparation of Pt nanorings when Saturn-like Au core/Pt shell nanoparticles are used. The diameter and wall thickness of both nanotubes and nanorings can be readily controlled in the range of 14-37 nm and 2-32 nm, respectively. We further demonstrated that the nanotubes with ultrathin side walls showed superior catalytic performance in oxygen reduction reaction. © 2016 American Chemical Society.

  1. Same-Side Platinum Electrodes for Metal Assisted Etching of Porous Silicon

    Science.gov (United States)

    2015-11-01

    depth by varying the local electrode/silicon (Si) ratio, the electrode will need to be cut up into electrically isolated sections or else the carriers...hydrogen peroxide (H2O2), and ethanol etch solution. The H2O2 reacts with hydrogen ions from the HF at the catalytic metal surface to become water ...the sample, or by hot gases at the flame front jetting across to a nearby PSi line. 4. Conclusions We have developed new procedures for etching

  2. Field guide to quick deployment thermocouples

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Instructions for quick deployment of thermocouples to measure fire intensity at Kulm Wetland Management District as part of the Fire Intensity Monitoring survey....

  3. Thiosemicarbazone complexes of the platinum metals. A story of variable coordination modes

    Indian Academy of Sciences (India)

    Indrani Pal; Falguni Basuli; Samaresh Bhattacharya

    2002-08-01

    Salicylaldehyde thiosemicarbazone (H2saltsc) reacts with [M(PPh3)3X2] (M = Ru, Os; X = Cl, Br) to afford complexes of type [M(PPh3)2(Hsaltsc)2], in which the salicylaldehyde thiosemicarbazone ligand is coordinated to the metal as a bidentate N,S-donor forming a four-membered chelate ring. Reaction of benzaldehyde thiosemicarbazones (Hbztsc-R) with [M(PPh3)3X2] also affords complexes of similar type, viz. [M(PPh3)2(bztsc-R)2], in which the benzaldehyde thiosemicarbazones have also been found to coordinate the metal as a bidentate N,S-donor forming a fourmembered chelate ring as before. Reaction of the Hbztsc-R ligands has also been carried out with [M(bpy)2X2] (M = Ru, Os; X = Cl, Br), which has afforded complexes of type [M(bpy)2(bztsc-R)]+, which have been isolated as perchlorate salts. Coordination mode of bztsc-R has been found to be the same as before. Structure of the Hbztsc-OMe ligand has been determined and some molecular modelling studies have been carried out determine the reason for the observed mode of coordination. Reaction of acetone thiosemicarbazone (Hactsc) has then been carried out with [M(bpy)2X2] to afford the [M(bpy)2(actsc)]ClO4 complexes, in which the actsc ligand coordinates the metal as a bidentate N,S-donor forming a five-membered chelate ring. Reaction of H2saltsc has been carried out with [Ru(bpy)2Cl2] to prepare the [Ru(bpy)2(Hsaltsc)]ClO4 complex, which has then been reacted with one equivalent of nickel perchlorate to afford an octanuclear complex of type [{Ru(bpy)2(saltsc-H)}4Ni4](ClO4)4.

  4. [Synthesis and luminescent spectral characteristics of porphyrin complexes with platinum group metals].

    Science.gov (United States)

    Rumiantseva, V D; Ivanovskaia, N P; Konovalenko, L I; Tsukanov, S V; Mironov, A F; Osin, N S

    2008-01-01

    The synthesis of natural and synthetic porphyrin complexes with Pt, Pd, Rh, and Ru is reported. Their electronic absorption spectra, phosphorescence spectra, and lifetimes at room temperature both in the presence and in the absence of oxygen were studied. It has been shown that the variation of the nature of the central metal atom and of the substituents in pyrrole and phenyl rings allows the obtaining of metalloporphyrins with various phosphorescence excitation and phosphorescing emission spectra at room temperature. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru.

  5. Magnesium, zinc, arsenic, selenium and platinum urinary excretion from cancer patients of Antofagasta region, Chile: multi-metal approach

    Science.gov (United States)

    Pizarro, I; Rivera, L; Ávila, J; Cortés, P

    2016-01-01

    Objectives To evaluate the short-term 24 h urinary excretion of platinum, arsenic, selenium, magnesium and zinc in patients with lung cancer and with cancer other than lungs treated with cisplatin or/and carboplatin from Antofagasta, Chile. Design Urine measurements of Pt and Se were made by inductively coupled plasma optical emission spectrometry, As by hydride-generation atomic absorption spectrometry and Mg and Zn by means of flame furnace atomic absorption spectrometry. Setting All samples were provided by the Oncological Centre of Antofagasta Regional Hospital (Region of Antofagasta, Chile). Participants Ninety 24-h urine samples from cancer patients after the infusion of Pt-base drugs and 10 24-h urine samples from cancer patients not treated with metal-base drugs. Main outcome measures Concentrations of Pt, Se, As, Zn and Mg coming from 24-h urine samples. Results Pt excreted was not significantly different between patients with lung and other cancers treated with cisplatin. The excretion of Mg, Zn and Se was greater than As. Then, Pt favours the excretion of essential elements. For lung and other types of cancers treated with drugs without Pt, excretion of Mg, Zn and Se was also greater than that of As, suggesting antagonism Mg-Zn-Se–anti-cancer drug relationship. Conclusions The amounts of Mg, Zn and Se excreted were greater than for As either with or without Pt-containing drugs, suggesting antagonist Mg-Zn-Se–anti-cancer drug relationships. The excretion of As, Mg, Zn and Se is induced by Pt. Knowledge obtained can contribute to understanding the arsenic cancer mechanism and the As-Mg-Zn-Se-Pt inter-element association for lung cancer and other types of cancer. PMID:27757244

  6. Global mining risk footprint of critical metals necessary for low-carbon technologies: the case of neodymium, cobalt, and platinum in Japan.

    Science.gov (United States)

    Nansai, Keisuke; Nakajima, Kenichi; Kagawa, Shigemi; Kondo, Yasushi; Shigetomi, Yosuke; Suh, Sangwon

    2015-02-17

    Meeting the 2-degree global warming target requires wide adoption of low-carbon energy technologies. Many such technologies rely on the use of precious metals, however, increasing the dependence of national economies on these resources. Among such metals, those with supply security concerns are referred to as critical metals. Using the Policy Potential Index developed by the Fraser Institute, this study developed a new footprint indicator, the mining risk footprint (MRF), to quantify the mining risk directly and indirectly affecting a national economy through its consumption of critical metals. We formulated the MRF as a product of the material footprint (MF) of the consuming country and the mining risks of the countries where the materials are mined. A case study was conducted for the 2005 Japanese economy to determine the MF and MRF for three critical metals essential for emerging energy technologies: neodymium, cobalt and platinum. The results indicate that in 2005 the MFs generated by Japanese domestic final demand, that is, the consumption-based metal output of Japan, were 1.0 × 10(3) t for neodymium, 9.4 × 10(3) t for cobalt, and 2.1 × 10 t for platinum. Export demand contributes most to the MF, accounting for 3.0 × 10(3) t, 1.3 × 10(5) t, and 3.1 × 10 t, respectively. The MRFs of Japanese total final demand (domestic plus export) were calculated to be 1.7 × 10 points for neodymium, 4.5 × 10(-2) points for cobalt, and 5.6 points for platinum, implying that the Japanese economy is incurring a high mining risk through its use of neodymium. This country's MRFs are all dominated by export demand. The paper concludes by discussing the policy implications and future research directions for measuring the MFs and MRFs of critical metals. For countries poorly endowed with mineral resources, adopting low-carbon energy technologies may imply a shifting of risk from carbon resources to other natural resources, in particular critical metals, and a trade

  7. Probing Interaction Between Platinum Group Metal (PGM) and Non-PGM Support Through Surface Characterization and Device Performance

    Science.gov (United States)

    Saha, Shibely

    High cost and limited abundance of Platinum (Pt) have hindered effective commercialization of Proton Exchange Membrane Fuel Cell and Electrolyzer. Efforts have been undertaken to reduce precious group metal (PGM) requirement for these devices without compromising the activity of the catalyst by using transition metal carbides (TMC) as non-PGM support thanks to their similar electronic and geometric structures as Pt. In this work Mo2C was selected as non-PGM support and Pt was used as the PGM of interest. We hypothesize that the hollow nanotube morphology of Mo2C support combined with Pt nano particles deposited on it via atomic layer deposition (ALD) technique would allow increased interaction between them which may increase the activity of Pt and Mo2C as well as maximize the Pt active surface area. Specifically, a rotary ALD equipment was used to grow Pt particles from atomic level to 2--3 nanometers by simply adjusting number of ALD cycles in order to probe the interaction between the deposited Pt nanoparticles and Mo2C nanotube support. Interaction between the Pt and Mo2 C was analyzed via surface characterization and electrochemical characterization. Interaction between Pt and Mo2C arises due to the lattice mismatch between Pt and Mo2C as well as electron migration between them. Lattice spacing analysis using high resolution transmission electron microscopy (HRTEM) images, combined with Pt binding energy shift in XPS results, clearly showed strong bonding between Pt nanoparticles and the Mo2C nanotube support in all the resultant Pt/Mo2C samples. We postulate that this strong interaction is responsible for the significantly enhanced durability observed in our constant potential electrolysis (CPE) and accelerated degradation testing (ADT). Of the three samples from different ALD cycles (15, 50 and 100), Mo2C nanotubes modified by 50 (1.07 wt% Pt loading) and 100 cycles (4.4 wt% Pt) of Pt deposition, showed higher HER and HOR activity per Pt mass than commercial

  8. Thermocouples in an alternating magnetic field (AMF) for studying magnetic nanoparticle hyperthermia

    Science.gov (United States)

    Hartzell, S.; Boekelheide, Z.

    Magnetic nanoparticle hyperthermia, a method of cancer therapy, is currently a subject of active research. A critical parameter during therapy or laboratory research is the temperature of the system (tissue or nanoparticle suspension). Thermocouples are affordable and ubiquitous temperature sensors which could be used in this capacity; however, their metallic nature results in self-heating due to eddy currents when placed in an AMF. This presentation will quantitatively discuss calculations and measurements of the self-heating of three common types of thermocouples. Type T, K, and E thermocouples of both thin (40 gauge) and thick (20 gauge) wires were tested in a range of applied magnetic field magnitudes (235 kHz, 0-0.4 T rms). Among the thermocouples, all three types demonstrated large self-heating in 20 gauge wires. For the 40 gauge wires, type K showed large self-heating, while type T showed small but significant self-heating and type E showed no significant self-heating in comparison to the background. Our results indicate that thin type E thermocouples can be accurately used as temperature sensors in an AMF environment similar to the one used here, and type T thermocouples may be appropriate under conditions with lower magnetic field strength or frequency.

  9. Development and Testing of Tungsten-rhenium Thermocouples%钨铼热电偶开发与测试

    Institute of Scientific and Technical Information of China (English)

    王彦明; 郝彦军

    2012-01-01

    近年来随着钨铼丝测温精度的不断提高,并因其廉价性,钨铼型快速热电偶将逐渐替代铂铑型快速热电偶。介绍钨铼热电偶开发与测试过程中的一些要点。%In recent years, with the continuous improvement of the tungsten-rhenium wire temperature measurement accuracy, and its cheap, fast tungsten-rhenium thermocouples will gradually replace the platinum and rhodium fast thermocouple. This article describes some of the key points in the tungsten-rhenium thermocouples development and testing process.

  10. Diarylplatinum(II Compounds as Versatile Metallating Agents in the Synthesis of Cyclometallated Platinum Compounds with N-Donor Ligands

    Directory of Open Access Journals (Sweden)

    Margarita Crespo

    2014-03-01

    Full Text Available This review deals with the reactions of diarylplatinum(II complexes with N-donor ligands to produce a variety of cycloplatinated compounds including endo-five-, endo-seven-, endo-six- or exo-five-membered platinacycles. The observed reactions result from a series of oxidative addition/reductive elimination processes taking place at platinum(II/platinum(IV species and involving C–X (X = H, Cl, Br bond activation, arene elimination, and, in some cases, Caryl–Caryl bond formation.

  11. New heteronuclear gold(I)-platinum(II) complexes with cytotoxic properties : Are two metals better than one?

    NARCIS (Netherlands)

    Wenzel, Margot; Bigaeva, Emilia; Richard, Philippe; Le Gendre, Pierre; Picquet, Michel; Casini, Angela; Bodio, Ewen

    2014-01-01

    A series of mono- and heterodinuclear gold(I) and platinum(II) complexes with a new bipyridylamine-phosphine ligand have been synthesized and characterized. The X-ray structures of the ligand precursor 4-iodo-N,N-di(pyridin-2-yl)benzamide, and of one gold derivative are reported. All the complexes d

  12. Accelerated growth from amorphous clusters to metallic nanoparticles observed in electrochemical deposition of platinum within nanopores of porous silicon

    NARCIS (Netherlands)

    Munoz-Noval, Alvaro; Fukami, Kazuhiro; Koyama, Akira; Gallach, Dario; Hermida-Merino, Daniel; Portale, Giuseppe; Kitada, Atsushi; Murase, Kuniaki; Abe, Takeshi; Hayakawa, Shinjiro; Sakka, Tetsuo

    2016-01-01

    This study examined the formation of amorphous platinum (Pt) clusters in nanopores of porous silicon at an initial stage of pore filling. The time dependency of the chemical state and local structure of Pt in the nanoporous silicon were characterized by X-ray absorption fine structure spectroscopy (

  13. Process Simulating of Heat Transfer in High-temperature Thermocouples

    Directory of Open Access Journals (Sweden)

    Atroshenko Yuliana K.

    2015-01-01

    Full Text Available Numerical research of integral characteristics of process of heattransfer in sensitive elements of R, A and B types thermocouples in case of measurement of high temperatures (more than 900 K is executed. Theoretical dependences of minimum necessary duration of heating up of the thermocouple on value of temperature on boundary of a sensitive element are received. It is shown the thermocouple of R type requires bigger time of heating for obtaining satisfactory accuracy of measurements. Temperature fields in sensitive elements of the specified thermocouples are received. It is shown that distribution of temperature on the thermocouple not linearly and has similar character for the researched thermocouples.

  14. Temperature Measurements Using Type K Thermocouples and the Fluke Helios Plus 2287A Datalogger

    DEFF Research Database (Denmark)

    Artmann, Nikolai; Vonbank, R.; Jensen, Rasmus Lund

    In 1821, the German–Estonian physicist Thomas Johann Seebeck discovered that when any conductor (such as a metal) is subjected to a thermal gradient, it will generate a voltage. This is now known as the thermoelectric effect or Seebeck effect. Any attempt to measure this voltage necessarily invol...... metal combinations. Certain combinations have become popular as industry standards, driven by cost, availability, convenience, melting point, chemical properties, stability, and output. This coupling of two metals gives the thermocouple its name....

  15. Experimental investigations of the hydrothermal geochemistry of platinum and palladium: V. Equilibria between platinum metal, Pt(II), and Pt(IV) chloride complexes at 25 to 300°C

    Science.gov (United States)

    Gammons, Christopher H.

    1996-05-01

    The solubility of metallic Pt in HCl solutions was determined at 200 to 300°C at oxidation states buffered near the aqueous Pt(II)/Pt(IV) boundary. Equilibrium constants were obtained for the following disproportionation reactions: log K, 200° 250° 300°C 2PtCl 42- = PtCl 42- + Pt(s) + 2Cl - 1.47 1.70 1.54 (a) 2PtCl 3- = PtCl 5- + Pt(s) + Cl - 1.77 1.74 1.37 (b) with experimental uncertainties of approximately ±0.20 log units. These results are found to be in good agreement with previously published estimates for reaction at 60 to 152.5°C. The data indicate that the relative stability of the Pt(II) and Pt(IV) chloride complexes does not change appreciably with temperature. This is in contrast to previous work in the Au(0)/Au(I)/Au(III) system which demonstrates that the Au(I) chloride complexes are unstable with respect to Au (III) at low temperature, but become the dominant aqueous species at 300°C. Pt(IV) chloride complexes are unlikely to be important in high temperature hydrothermal fluids, as unrealistically high aqueous platinum concentrations are required to stabilize these species relative to Pt(II). In contrast, thermodynamic calculations suggest that Pt(IV) chloride or hydroxychloride complexes may be the dominant form of dissolved platinum in low temperature brines that are strongly oxidized (e.g., seawater). In oxygenated, Cl-rich solutions, the solubility of Pt is extremely high at pH < 6, such that the mobility of this metal will most likely be limited by surface adsorption reactions and/ or its abundance and rate of dissolution in the enclosing rock or soil. At neutral to alkaline pH, calculated solubilities are much lower, and saturation with Pt oxide phases may occur, as has recently been described in nature.

  16. Welding Wires To Thin Thermocouple Films

    Science.gov (United States)

    Holanda, Raymond; Kim, Walter S.; Danzey, Gerald A.; Pencil, Eric; Wadel, Mary

    1993-01-01

    Parallel-gap resistance welding yields joints surviving temperatures of about 1,000 degrees C. Much faster than thermocompression bonding. Also exceeds conductive-paste bonding and sputtering thin films through porous flame-sprayed insulation on prewelded lead wires. Introduces no foreign material into thermocouple circuit and does not require careful control of thickness of flame-sprayed material.

  17. Performance Evaluation of an Infrared Thermocouple

    Directory of Open Access Journals (Sweden)

    Te-Ching Shen

    2010-11-01

    Full Text Available The measurement of the leaf temperature of forests or agricultural plants is an important technique for the monitoring of the physiological state of crops. The infrared thermometer is a convenient device due to its fast response and nondestructive measurement technique. Nowadays, a novel infrared thermocouple, developed with the same measurement principle of the infrared thermometer but using a different detector, has been commercialized for non-contact temperature measurement. The performances of two-kinds of infrared thermocouples were evaluated in this study. The standard temperature was maintained by a temperature calibrator and a special black cavity device. The results indicated that both types of infrared thermocouples had good precision. The error distribution ranged from −1.8 °C to 18 °C as the reading values served as the true values. Within the range from 13 °C to 37 °C, the adequate calibration equations were the high-order polynomial equations. Within the narrower range from 20 °C to 35 °C, the adequate equation was a linear equation for one sensor and a two-order polynomial equation for the other sensor. The accuracy of the two kinds of infrared thermocouple was improved by nearly 0.4 °C with the calibration equations. These devices could serve as mobile monitoring tools for in situ and real time routine estimation of leaf temperatures.

  18. New surfactant phosphine ligands and platinum(II) metallosurfactants. Influence of metal coordination on the critical micelle concentration and aggregation properties.

    Science.gov (United States)

    Parera, Elisabet; Comelles, Francesc; Barnadas, Ramon; Suades, Joan

    2010-01-19

    We have prepared the first platinum(II) metallosurfactants from a new family of linear surfactant phosphines Ph(2)P(CH(2))(n)SO(3)Na {1 (n = 2), 2 (n = 6), and 3 (n = 10)}, which were synthesized by reaction between the halosulfonates X(CH(2))(n)SO(3)Na and sodium diphenylphosphide. The metallosurfactants cis-[PtCl(2)L(2)] (L = 1-3) were obtained after reaction between the phosphines and PtCl(2) in dimethylsulfoxide. All compounds were fully characterized by the usual methods {NMR ((1)H, (13)C, (31)P, (195)Pt), IR, MS-ESI and HRMS}. By exploring the surfactant properties of phosphines 1-3 and their respective platinum metallosurfactants cis-[PtCl(2)L(2)] (L = 1-3) through surface tension measurements, dynamic light scattering spectroscopy, and cryo-TEM microscopy, we were able to analyze the influence of the metal coordination on the critical micelle concentration (cmc) and the aggregation properties. The cmc values of platinum metallosurfactants were considerably lower than those obtained for the free phosphines 1-3. This behavior could be understood by an analogy between the structure of cis-[PtCl(2)L(2)] complexes and bolaform surfactants. The calculated values of area per molecule also showed different tendencies between 1-3 and cis-[PtCl(2)L(2)] complexes, which could be explained on the basis of the possible conformations of these compounds in the air-water interface. The study of aggregates by dynamic light scattering spectroscopy and cryo-TEM microscopy showed the formation of spherical disperse medium size vesicles in all cases. However, substantial differences were observed between the three free phosphines (the population of micellar aggregates increased with long chain length) and also between phosphines and their respective metallosurfactants.

  19. 一种简便易行的实验室间热电偶校准能力的评定方法%Simple Method of Assessment of Thermocouple Calibration Capability between Laboratory

    Institute of Scientific and Technical Information of China (English)

    赵楠; 吴方; 刘丹英

    2015-01-01

    本文依据在二等标准铂铑10-铂热电偶能力验证中多个实验室提供的数据,给出了一种简便易行的实验室间热电偶校准能力评定的方法。%Based on multiple lab data which is from the capability validation of second-class standard Platinum-10%Rhodium/Platinum Thermocouple, a simple method of the assessment of thermocouple calibration capability between laboratory was provided.

  20. Minimizing the self-heating artefacts due to the microwave irradiation of thermocouples.

    Science.gov (United States)

    Dunscombe, P B; Constable, R T; McLellan, J

    1988-01-01

    The self-heating of metallic thermocouples in therapeutic microwave fields has long been recognized as a source of temperature artefacts in clinical hyperthermia dosimetry. We examine several techniques by which the probe and tissue heating artefacts resulting from self-heating may be quantitatively assessed, and discuss these in the context of their applicability to clinical hyperthermia.

  1. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  2. Experimental observations on noble metal nanonuggets and Fe-Ti oxides, and the transport of platinum group elements in silicate melts

    Science.gov (United States)

    Anenburg, Michael; Mavrogenes, John A.

    2016-11-01

    Platinum group element (PGE) nanonuggets are a nuisance in experimental studies designed to measure solubility or partitioning of noble metals in silicate melts. Instead of treating nanonuggets as experimental artifacts, we studied their behaviour motivated by recent discoveries of PGE nanonuggets in a variety of natural settings. We used an experimental setup consisting of AgPd, Pt or AuPd capsules and Fe(-Ti) oxide-saturated hydrous peralkaline silicate melts to maximise nanonugget production. TABS (Te, As, Bi, Sb, Sn) commonly occur in PGM (platinum group minerals), prompting addition of Bi to our experiments to investigate its properties as well. Three-dimensional optical examination by 100× objective and immersion oil reveals variable colour which correlates with nanonugget size and shape due to plasmon resonance effects. We observe two textural types: (1) intermediate-sized nanonuggets dispersed in the glass and adhering to oxides, and (2) abundant fine nanonuggets dispersed in the glass with coarse euhedral crystals in contact with oxides. Slow cooling removes dispersed nanonuggets and greatly coarsens existing oxide-associated metal crystals. Nanonugget-free halos are commonly observed around oxide grains. All metal phases are composed of major (Ag, Pd) and trace (Pt, Ir, Au) capsule material. Our results show reduction processes, imposed by growing oxides, causing local metal saturation in the oxide rich zones with preferential nucleation on smaller oxide grains. The redox gradient then blocks additional metals from diffusing into oxide rich zones, forming halos. As the entire experimental charge is reduced throughout the run, nanonuggets form in the distal glass. Bismuth contents of metal phases do not depend on Bi2O3 amounts dissolved in the melt. Further PGM crystallisation consumes nanonuggets as feedstock. We conclude that the appearance of metallic PGE phases happens in two stages: first as nanonuggets and then as larger PGM. Once formed

  3. H{sub 2}/air alkaline membrane fuel cell performance and durability, using novel ionomer and non-platinum group metal cathode catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Piana, Michele; Boccia, Massimiliano; Filpi, Antonio; Flammia, Elisa; Miller, Hamish A.; Orsini, Marco; Salusti, Francesca; Santiccioli, Serena [Acta S.p.A., Fuel cell Technology, via di Lavoria 56/G, I-56042 Crespina (PI) (Italy); Ciardelli, Francesco; Pucci, Andrea [Department of Chemistry and Industrial Chemistry, University of Pisa, Via, Risorgimento 35, I-56126 Pisa (Italy)

    2010-09-15

    The development of H{sub 2}/air alkaline membrane fuel cells (AMFCs) enables the use of non-platinum group metal (PGM) catalysts which are intrinsically stable and have an activity similar to platinum in alkaline media for the oxygen reduction reaction (ORR). As opposed to PEMFCs, the research and development of these types of catalysts for AMFC has had little attention and even less has been given to the development of alkaline membranes and ionomers. Acta S.p.A. has developed recently new non-PGM ORR catalysts with activity higher than Pt in alkaline media. More importantly, a new anionic ionomer derived from cheap starting materials with optimum performance has been produced. In this paper we demonstrate the use of this new ionomer in H{sub 2}/air AMFCs showing the first polarization and durability data, with current densities higher than those recently reported in the literature. Furthermore, we report the effect of CO{sub 2} on AMFC performance, showing the possibility of use of such alkaline devices not only in outer-space applications, but also with atmospheric air for large scale devices. (author)

  4. Establishment of the Co-C Eutectic Fixed-Point Cell for Thermocouple Calibrations at NIMT

    Science.gov (United States)

    Ongrai, O.; Elliott, C. J.

    2017-08-01

    In 2015, NIMT first established a Co-C eutectic temperature reference (fixed-point) cell measurement capability for thermocouple calibration to support the requirements of Thailand's heavy industries and secondary laboratories. The Co-C eutectic fixed-point cell is a facility transferred from NPL, where the design was developed through European and UK national measurement system projects. In this paper, we describe the establishment of a Co-C eutectic fixed-point cell for thermocouple calibration at NIMT. This paper demonstrates achievement of the required furnace uniformity, the Co-C plateau realization and the comparison data between NIMT and NPL Co-C cells by using the same standard Pt/Pd thermocouple, demonstrating traceability. The NIMT measurement capability for noble metal type thermocouples at the new Co-C eutectic fixed point (1324.06°C) is estimated to be within ± 0.60 K (k=2). This meets the needs of Thailand's high-temperature thermocouple users—for which previously there has been no traceable calibration facility.

  5. Thermocouple Errors when Mounted on Cylindrical Surfaces in Abnormal Thermal Environments.

    Energy Technology Data Exchange (ETDEWEB)

    Nakos, James T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Suo-Anttila, Jill M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zepper, Ethan T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Koenig, Jerry J [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Valdez, Vincent A. [ECI Inc., Albuquerque, NM (United States)

    2017-05-01

    Mineral-insulated, metal-sheathed, Type-K thermocouples are used to measure the temperature of various items in high-temperature environments, often exceeding 1000degC (1273 K). The thermocouple wires (chromel and alumel) are protected from the harsh environments by an Inconel sheath and magnesium oxide (MgO) insulation. The sheath and insulation are required for reliable measurements. Due to the sheath and MgO insulation, the temperature registered by the thermocouple is not the temperature of the surface of interest. In some cases, the error incurred is large enough to be of concern because these data are used for model validation, and thus the uncertainties of the data need to be well documented. This report documents the error using 0.062" and 0.040" diameter Inconel sheathed, Type-K thermocouples mounted on cylindrical surfaces (inside of a shroud, outside and inside of a mock test unit). After an initial transient, the thermocouple bias errors typically range only about +-1-2% of the reading in K. After all of the uncertainty sources have been included, the total uncertainty to 95% confidence, for shroud or test unit TCs in abnormal thermal environments, is about +-2% of the reading in K, lower than the +-3% typically used for flat shrouds. Recommendations are provided in Section 6 to facilitate interpretation and use of the results. .

  6. Printed organic conductive polymers thermocouples in textile and smart clothing applications.

    Science.gov (United States)

    Seeberg, Trine M; Røyset, Arne; Jahren, Susannah; Strisland, Frode

    2011-01-01

    This work reports on an experimental investigation of the potential of using selected commercially available organic conductive polymers as active ingredients in thermocouples printed on textiles. Poly(3, 4-ethylenedioxythiophene): poly(4 styrenesulfonate) (PEDOT:PSS) and polyaniline (PANI) were screen printed onto woven cotton textile. The influence of multiple thermocycles between 235 K (-38 °C) and 350 K (+77 °C) on resistivity and thermoelectric properties was examined. The Seebeck coefficients of PEDOT:PSS and PANI were found to be about +18 μV/K and +15 uV/K, respectively, when "metal-polymer" thermocouples were realized by combining the polymer with copper. When "polymer-polymer" thermocouples were formed by combining PEDOT:PSS and PANI, a thermoelectric voltage of about +10 μV/K was observed. A challenge recognized in the experiments is that the generated voltage exhibited drift and fluctuations.

  7. A Quantitative Model for the Thermocouple Effect Using Statistical and Quantum Mechanics

    Science.gov (United States)

    Bramley, Paul; Clark, Stewart

    2003-09-01

    This paper employs statistical and quantum mechanics to develop a model for the mechanism underlying the Seebeck effect. The conventional view of the equilibrium criterion for valence electrons in a material is that the Fermi Energy should be constant throughout the system. However, this criterion is an approximation and it is shown to be inadequate for thermocouple systems. An improved equilibrium criterion is developed by applying statistical and quantum mechanics to determine the total flow of electrons across an arbitrary boundary within a system. Dynamic equilibrium is then considered to be the situation where the Fermi Energy either side of the boundary is such that the flow of electrons in each direction is the same. This equilibrium criterion is then applied to the conditions along the thermocouple wires and at the junctions in order to generate a model for the Seebeck effect. The equations involved for calculating the electronic structure of a material cannot be solved analytically, so a solution is achieved using numeric models employing CASTEP code running on a Sun Beowulf cluster and iterative algorithms written in the Excel™ VBA language on a PC. The model is used to calculate the EMF versus temperature function for the gold versus platinum thermocouple, which is then compared with established experimental data.

  8. Ultraviolet Spectroscopy of Metal-Poor Stars: New Detections of Phosphorus, Germanium, Arsenic, Selenium, Cadmium, Tellurium, Lutetium, Osmium, Iridium, Platinum, Gold, and More!

    Science.gov (United States)

    Roederer, Ian U.

    2015-01-01

    Ultraviolet spectroscopy with HST/STIS provides a 30% increase in the number of elements that can be detected in metal-poor stars. Although nearly every element from hydrogen through bismuth is probably present in most metal-poor stars, not all elements can be detected. The resonance lines of the dominant species of some elements are only found in the UV in late-type stars. The chemical compositions of these stars reflect the history of stellar nucleosynthesis from the first stars to today. Here, I present a summary of recent work that has expanded the chemical inventory in metal-poor stars using UV spectroscopy conducted using HST/STIS. The highlights include new detections of phosphorus, germanium, arsenic, selenium, cadmium, tellurium, lutetium, osmium, iridium, platinum, and gold in metal-poor stars. These detections reveal new insights into stellar nucleosynthesis in the earliest generations of massive stars, provide new constraints on the r-process, and open new channels for chemically-tagging stars that have assembled to form the Milky Way stellar halo.

  9. Uncertainty Estimation of Measurement Result of Grade ⅡInexpensive Metal Thermocouple for an Industrial Use Below 300℃%300℃以下Ⅱ级工业用廉金属热电偶示值误差测量结果的不确定度评定

    Institute of Scientific and Technical Information of China (English)

    杨保成; 杨立; 谢志辉

    2016-01-01

    为了评定300℃以下Ⅱ级工业用廉金属热电偶示值误差测量结果的不确定度,依据GJB3756—99《测量不确定度的表示及评定》、JJF1059.1—2012《测量不确定度评定与表示》和JJG351—96《工作用廉金属热电偶检定规程》等标准和规范,设计了校准方案,分析了测量不确定度的来源,建立了测量模型;分别采用A类和B类方法对各标准不确定度分量进行评定,在确定合成标准不确定度和扩展不确定度之后,得到测量不确定度。%In order to estimate the uncertainty of measurements error of gradeⅡinexpensive metal thermocouple for industrial use below 300℃, based on standards and specifications GJB3756—99 Calibration Procedure ofInexpensive Metal Thermocouple for Working,JJF1059.1—2012 Representation and Evaluation of Uncertainty Measurement and JJG35 1—96 Representation and Evaluation of Uncertainty Measurement,a calibration method was designed,and the sources of the uncertainty of measurement was analyzed,and the measuring model was established,and the uncertainty components were assessed using class A and class B method respectively.The uncertainty of measurements was obtained after the synthetic standard uncertainty and the expanded uncertainty were determined.

  10. Computer program for pulsed thermocouples with corrections for radiation effects

    Science.gov (United States)

    Will, H. A.

    1981-01-01

    A pulsed thermocouple was used for measuring gas temperatures above the melting point of common thermocouples. This was done by allowing the thermocouple to heat until it approaches its melting point and then turning on the protective cooling gas. This method required a computer to extrapolate the thermocouple data to the higher gas temperatures. A method that includes the effect of radiation in the extrapolation is described. Computations of gas temperature are provided, along with the estimate of the final thermocouple wire temperature. Results from tests on high temperature combustor research rigs are presented.

  11. The Linearized Design Of Thermocouple Sensor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>There are large errors of linear measurement when the thermocouple measure temperature as temperature sensor.In order to improve the measurement precision,the sensor cold junction compensation and nonlinear compensation are usually needed.For the circumstances that the cold junction’s temperature is determinate,there is biggish nonlinear between thermoelectric power and temperature signals of the thermocouple sensor’s output.In order to solve the problem,this paper proposed a practical method of linear compensation,introduced the principle of linear compensation and gave the corresponding compensation circuit and circuit analysis.This circuit has the characteristic of simpleness,high reliability,small linear error and so on.

  12. Use of manganin-constantan thermocouples in thermometry units designed for copper-constantan thermocouples.

    Science.gov (United States)

    Hoh, L L; Waterman, F M

    1995-01-01

    Commercial ultrasound hyperthermia systems typically include thermometry units designed for copper-constantan thermocouples. Replacing these copper-constantan thermocouples with manganin-constantan thermocouples is advantageous in reducing the measurement error caused by the conduction of heat along the copper wire, but their performance in these thermometry units is uncertain. The accuracy of manganin-constantan thermocouples in the Labthermics LT-100, Clini-Therm TS1200/TM100, and Physitemp TM-12 thermometry units was investigated using a temperature controlled circulating water bath monitored by a mercury thermometer having a calibration traceable to NIST. The results demonstrate that an accuracy of +/- 0.2 degrees C can be achieved with manganin-constantan thermocouples over the range 35-55 degrees C without hardware modification provided specific calibration procedures are followed. With the Labthermics LT-100, a double point calibration should be carried out at 35 and 55 degrees C. With the Clini-Therm TS1200/TM100, a self-calibration of the unit using its internal calibration well plus a single point calibration using an external temperature standard provides sufficient accuracy. The Physitemp TM-12 requires an external computer for read out and the user must provide additional software to correct for the error by either a single or multiple point calibration.

  13. Levels of Platinum Group Metals in Selected Species (Sarotherodon melanotheron, Chonophorus lateristriga, Macrobrachium vollenhovenii and Crassostrea tulipa in Some Estuaries and Lagoons Along the Coast of Ghana

    Directory of Open Access Journals (Sweden)

    D. K. Essumang

    2010-01-01

    Full Text Available The use of some biota as bioindicators of heavy metal pollution has been demonstrated as particularly adequate due to their capacity of bioconcentration. This study evaluated the levels of platinum group metals (PGMs in some selected species along the coastal belt of Ghana, using the neutron activation analysis (NAA method. The result was processed to evaluate pollution indices in order to map the distribution of the metals in those species in the lagoons and estuaries along the costal belt of Ghana. The analysis showed significant levels of all PGMs in blackchin tilapia (Sarotherodon melanotheron Cichlidae, brown goby (Chonophorus lateristriga Gobiidae, shrimp (Macrobrachium vollenhovenii Palaemonidae, and mangrove oysters (Crassostrea tulipa Ostreidae in the lagoons and river Pra estuary. However, the oysters showed an elevated mean concentration of 0.13 μ/g (dry weight Pd. From the pollution indices, most of the sampling sites registered mean contamination factor (CF values between 1.20 and 3.00 for Pt, Pd, and Rh. The pollution load index (PLI conducted also gave an average pollution index between 0.79 and 2.37, indicating progressive contamination levels. The results revealed that anthropogenic sources, industrial and hospital effluent, etc., together with vehicular emissions, could be the contributing factors to the deposition of PGMs along the Ghanaian coast.

  14. Investigation of the usefulness of NTA, EDTA and DTPA in separation of some platinum metals on cellulose exchangers.

    Science.gov (United States)

    Brajter, K; Słonawska, K

    1980-09-01

    The possibility of using NTA, EDTA and DTPA as complexing agents for separation of some platinum group ions on cellulose ion-exchangers has been investigated. The greatest differences in the affinities of Pd(II) and Pt(IV) toward the cellulose ion-exchangers are obtained in the presence of DPTA, Cellex D (as ion-exchanger) in hydroxide form. The column separation of Pd(II) from Pt(IV), Rh(III) from Pd(II) and of a Rh(III)Pd(II)Pt(IV) mixture can be achieved with DPTA and chloride solutions. The method can be for determination of the components of RhPdPt alloys.

  15. Study on separation of platinum group metals from high level liquid waste using macroporous (MOTDGA-TOA)/SiO{sub 2}-P silica-based absorbent

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Tatsuya [Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Aoba 6-6, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Japan Atomic Energy Agency, Tokai-mura Naka-gun, Ibarak319-1195 (Japan); Kim, Seong-Yun; Xu, Yuanlai; Hitomi, Keitaro [Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Ishii, Keizo [Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Aoba 6-6, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Nagaishi, Ryuji; Kimura, Takaumi [Japan Atomic Energy Agency, Tokai-mura Naka-gun, Ibarak319-1195 (Japan)

    2013-07-01

    The recovery of platinum group metals (PGMs) from high level liquid waste (HLLW) by macroporous silica-based adsorbent, (MOTDGA-TOA)/SiO{sub 2}-P has been developed by impregnating two extractants of N,N'-dimethyl-N,N'-di-n-octyl-thio-diglycolamide (MOTDGA) and tri-n-octylamine (TOA) into a silica/polymer composite support (SiO{sub 2}-P). The adsorption of Ru(III), Rh(III) and Pd(II) have been investigated in simulated HLLW by batch method. The adsorbent has shown good uptake property for Pd(II). In addition, the combined use of MOTDGA and TOA improved the adsorption of Ru(III) and Rh(III) better than the individual use of them. The usability of adsorbent in radiation fields was further confirmed by irradiation experiments. The adsorbent remained to have the uptake capability for PGMs over the absorbed dose of 100 kGy, corresponding with one really adsorbed by the adsorbent, and showed good retention capability for Pd(II) even at the absorbed dose of 800 kGy. The chromatographic separation of metal ions was demonstrated with the adsorbent packed column, there is no influence of Re(VII) (instead of Tc) on the excellent separation behavior of Pd(II). (authors)

  16. Thermocouple design for measuring temperatures of small insects.

    Science.gov (United States)

    Hanson, A A; Venette, R C

    2013-01-01

    Contact thermocouples often are used to measure surface body temperature changes of insects during cold exposure. However, small temperature changes of minute insects can be difficult to detect, particularly during the measurement of supercooling points. We developed two thermocouple designs, which use 0.51 mm diameter or 0.127 mm diameter copper-constantan wires, to improve our ability to resolve insect exotherms. We tested the designs with adults from three parasitoid species: Tetrastichus planipennisi, Spathius agrili, and S. floridanus. These species are thermocouples than thick-gauge thermocouples for the smallest species tested, T. planipennisi. This difference was not apparent for larger species S. agrili and S. floridanus. Thermocouple design did not affect the mean supercooling point for any of the species. The cradle thermocouple design developed with the fine gauge wire was reusable and allowed for easy insect recovery after cold exposure.

  17. MODIFICATION OF TRANSITION METAL CATIONS TO POLYMER- STABILIZED PLATINUM COLLOIDAL CLUSTERS IN ENANTIOSELECTIVE HYDROGENATION OF METHYL PYRUVATE

    Institute of Scientific and Technical Information of China (English)

    Xiao-ping Yan; Bao-lin He; Jie Zhang; Han-fan Liu

    2005-01-01

    Modification of transition metal cations to polymer-stabilized Pt colloidal clusters modified with cinchonidine was studied in enantioselective hydrogenation of methyl pyruvate. Compared to the enantiomeric excess (e.e.) value (71.4%)obtained without the presence of metal cations, obvious e.e. enhancement (up to 82.5%) was resulted from the addition of Zn2+ but with a certain decrease in activity. The reaction parameters in the presence of Zn2+ were also studied. It was found that the Pt colloidal catalysts in the presence of metal cations performed very differently from that in the absence of metal cations.

  18. Process Simulating of Heat Transfer in High-temperature Thermocouples

    OpenAIRE

    Atroshenko Yuliana K.; Bychkova Alena A.

    2015-01-01

    Numerical research of integral characteristics of process of heattransfer in sensitive elements of R, A and B types thermocouples in case of measurement of high temperatures (more than 900 K) is executed. Theoretical dependences of minimum necessary duration of heating up of the thermocouple on value of temperature on boundary of a sensitive element are received. It is shown the thermocouple of R type requires bigger time of heating for obtaining satisfactory accuracy of measurements. Tempera...

  19. Thermocouple time constant measurement by cross power spectra

    Science.gov (United States)

    Strahle, W. C.; Muthukrishnan, M.

    1976-01-01

    A method of measuring thermocouple time constants is outlined which requires Fourier signal processing. In this method, two thermocouples of differing time constants are placed in a gas flow as closely as possible to one another, and the time constant of the first thermocouple is determined directly from the extremum of the imaginary part of the ratio of the ensemble averaged cross-power spectrum to the ensemble averaged auto-power spectrum of that thermocouple. A coherence function is given for assuring the quality of the data, and results are presented for an experimental test of the method. Some problems with the method are briefly noted.

  20. Primary endpoint results of the OMEGA Study: One-year clinical outcomes after implantation of a novel platinum chromium bare metal stent

    Energy Technology Data Exchange (ETDEWEB)

    Wang, John C., E-mail: john.wang@medstar.net [MedStar Union Memorial Hospital, Baltimore MD (United States); Carrié, Didier, E-mail: carrie.didier@chu-toulouse.fr [Centre Hôpital Universitaire Rangueil, Toulouse (France); Masotti, Monica, E-mail: MASOTTI@clinic.ub.es [Hospital Clinic, University of Barcelona (Spain); Erglis, Andrejs, E-mail: a.a.erglis@stradini.lv [Pauls Stradins Clinical University Hospital, University of Latvia, Riga (Latvia); Mego, David, E-mail: David.Mego@arheart.com [Arkansas Heart Hospital, Little Rock, AR (United States); Watkins, Matthew W., E-mail: Matthew.Watkins@vtmednet.org [University of Vermont Medical Center, Burlington VT (United States); Underwood, Paul, E-mail: Paul.underwood@bsci.com [Boston Scientific, Marlborough MA USA (United States); Allocco, Dominic J., E-mail: Dominic.allocco@bsci.com [Boston Scientific, Marlborough MA USA (United States); Hamm, Christian W., E-mail: C.Hamm@kerckhoff-klinik.de [Kerckhoff Heart and Thoraxcenter, Bad Nauheim (Germany)

    2015-03-15

    Background/purpose: Bare metal stents (BMS) have similar rates of death and myocardial infarction (MI) compared to drug-eluting stents (DES). DES lower repeat revascularization rates compared to BMS, but may have higher rates of late stent thrombosis (ST) potentially due to impaired endothelialization requiring longer dual anti-platelet therapy (DAPT). OMEGA evaluated a novel BMS designed to have improved deliverability and radiopacity, in comparison to currently available platforms. Methods/materials: OMEGA was a prospective, multicenter, single-arm study enrolling 328 patients at 37 sites (US and Europe). Patients received the OMEGA stent (bare platinum chromium element stent) for the treatment of de novo native coronary artery lesions (≤ 28 mm long; diameter ≥ 2.25 mm to ≤ 4.50 mm). The primary endpoint was 9-month target lesion failure (TLF: cardiac death, target vessel-related MI, target lesion revascularization [TLR]) compared to a prespecified performance goal (PG) based on prior generation BMS. All major cardiac events were independently adjudicated. DAPT was required for a minimum of 1 month post procedure. Results: In the OMEGA study, the mean age was 65; 17% had diabetes mellitus. The primary endpoint was met; 9 month TLF rate was 11.5%, and the upper 1-sided 95% confidence bound of 14.79% was less than the prespecified PG of 21.2% (p < 0.0001). One-year event rates were low including a TLF rate of 12.8% and an ST rate of 0.6% at 12 months. Conclusions: One-year outcomes of OMEGA show low rates of TLF, revascularization and ST. This supports safety and efficacy of the OMEGA BMS for the treatment of coronary artery disease. - Highlights: • The OMEGA study evaluated a novel platinum chromium bare metal stent. • OMEGA enrolled 328 patients at 37 sites (US and Europe). • The primary endpoint of 9 month target lesion failure was 11.5%. • One-year event rates were low including an ST rate of 0.6% at 12 months.

  1. DNA interaction studies of a platinum (II) complex containing an antiviral drug, ribavirin: the effect of metal on DNA binding.

    Science.gov (United States)

    Shahabadi, Nahid; Mirzaei kalar, Zeinab; Moghadam, Neda Hosseinpour

    2012-10-01

    The water-soluble Pt (II) complex, [PtCl (DMSO)(N(4)N(7)-ribavirin)]· H(2)O (ribavirin is an antiviral drug) has been synthesized and characterized by physico-chemical and spectroscopic methods. The binding interactions of this complex with calf thymus DNA (CT-DNA) were investigated using fluorimetry, spectrophotometry, circular dichroism and viscosimetry. The complex binds to CT-DNA in an intercalative mode. The calculated binding constant, K(b), was 7.2×10(5) M(-1). In fluorimetric studies, the enthalpy (ΔH0) changes of the reaction between the Pt (II) complex with CT-DNA showed hydrophobic interaction. In addition, CD study showed stabilization of the right-handed B form of CT-DNA. All these results prove that the complex interacts with CT-DNA via intercalative mode of binding. In comparison with the previous study of the DNA interaction with ribavirin, these results show that platinum complex has greater affinity to CT-DNA.

  2. 2-Methoxycycloocta-1,5-dienyl platinum complexes as precursors for platinum nanoparticles

    Indian Academy of Sciences (India)

    Ninad Ghavale; Sandip Dey; Vimal K Jain; R Tewari

    2009-02-01

    Thermolysis of [Pt2 (-OR)2 (C8H12OMe)2] (R = Me or Ac) in hexadecylamine (HDA) at 210°C under argon atmosphere gave platinum nanoparticles which were characterized by XRD, EDAX and TEM analysis. Both spherical (∼ 10 nm) and rod-like (∼ 19 nm length with aspect ratio of 2.3) face centred cubic (fcc) platinum metal nanoparticles could be isolated. The thermogravimetric analyses of these complexes revealed that they undergo a single step decomposition leading to the formation of platinum metal powder.

  3. Platinum group metal-free electrocatalysts: Effects of synthesis on structure and performance in proton-exchange membrane fuel cell cathodes

    Science.gov (United States)

    Workman, Michael J.; Dzara, Michael; Ngo, Chilan; Pylypenko, Svitlana; Serov, Alexey; McKinney, Sam; Gordon, Jonathan; Atanassov, Plamen; Artyushkova, Kateryna

    2017-04-01

    Development of platinum group metal free catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) requires understanding of the interactions between surface chemistry and performance, both of which are strongly dependent on synthesis conditions. To elucidate these complex relationships, a set of Fe-N-C catalysts derived from the same set of precursor materials is fabricated by varying several key synthetic parameters under controlled conditions. The results of physicochemical characterization are presented and compared with the results of rotating disk electrode (RDE) analysis and fuel cell testing. We find that electrochemical performance is strongly correlated with three key properties related to catalyst composition: concentrations of 1) atomically dispersed Fe species, 2) species in which N is bound to Fe, and 3) surface oxides. Not only are these factors related to performance, these types of chemical species are shown to correlate with each other. This study provides evidence supporting the role of iron coordinated with nitrogen as an active species for the ORR, and offers synthetic pathways to increase the density of atomically dispersed iron species and surface oxides for optimum performance.

  4. Nafion-Induced Metal-Metal Interactions in a Platinum(Ⅱ) Terpyridyl Acetylide Complex:a Luminescent Sensor for Detection of Volatile Organic Compounds

    Institute of Scientific and Technical Information of China (English)

    TONG,Qing-Xiao(佟庆笑); LI,Xiao-Hong(李晓红); WU,Li-Zhu(吴骊珠); YANG,Qing-Zheng(杨清正); ZHANG,Li-Ping(张丽萍); TUNG,Chen-Ho(佟振合)

    2004-01-01

    The platinum(Ⅱ) terpyridyl acetylide complex [Pt(terpy)(C≡CR)]C1O4 (terpy=2,2′: 6′2″-terpyridine, R=CH2CH2CH3) (1) was incorporated into Nafion membranes. At high loading the dry membranes exhibit intense photoluminescence with λmax at 707 nm from the 3MMLCT state, which was not observed in fluid solution. Upon exposure to the vapor of polar volatile organic compounds (VOC), this photoluminescence was significantly red-shifed. This process was fully reversible when the VOC-incorporated membrane was dried in air. The dramatic and reversible changes in the emission spectra made the Nafion-supported complex as an interesting sensor candidate for polar VOC.

  5. Thermocouple Extension-Wire-Connections and Low Temperatures

    Science.gov (United States)

    Figueroa, Fernando; Mitchell, Mark; Richardson, Gregory

    2000-01-01

    Experiments were carried out to determine the casue of erroneous readings from thermocouples of type K when measuring temperatures of liquid hydrogen. It was believed to be linked to te temperature of the connector used to extend the thermocouple wires to the voltage meter.

  6. Evaluating the abnormal ossification in tibiotarsi of developing chick embryos exposed to 1.0ppm doses of platinum group metals by spectroscopic techniques.

    Science.gov (United States)

    Stahler, Adam C; Monahan, Jennifer L; Dagher, Jessica M; Baker, Joshua D; Markopoulos, Marjorie M; Iragena, Diane B; NeJame, Britney M; Slaughter, Robert; Felker, Daniel; Burggraf, Larry W; Isaac, Leon A C; Grossie, David; Gagnon, Zofia E; Sizemore, Ioana E Pavel

    2013-04-01

    Platinum group metals (PGMs), i.e., palladium (Pd), platinum (Pt) and rhodium (Rh), are found at pollutant levels in the environment and are known to accumulate in plant and animal tissues. However, little is known about PGM toxicity. Our previous studies showed that chick embryos exposed to PGM concentrations of 1mL of 5.0ppm (LD50) and higher exhibited severe skeletal deformities. This work hypothesized that 1.0ppm doses of PGMs will negatively impact the mineralization process in tibiotarsi. One milliliter of 1.0ppm of Pd(II), Pt(IV), Rh(III) aqueous salt solutions and a PGM-mixture were injected into the air sac on the 7th and 14th day of incubation. Control groups with no-injection and vehicle injections were included. On the 20th day, embryos were sacrificed to analyze the PGM effects on tibiotarsi using four spectroscopic techniques. 1) Micro-Raman imaging: Hyperspectral Raman data were collected on paraffin embedded cross-sections of tibiotarsi, and processed using in-house-written MATLAB codes. Micro-Raman univariate images that were created from the ν1(PO4(3-)) integrated areas revealed anomalous mineral inclusions within the bone marrow for the PGM-mixture treatment. The age of the mineral crystals (ν(CO3(2-))/ν1(PO4(3-))) was statistically lower for all treatments when compared to controls (p≤0.05). 2) FAAS: The percent calcium content of the chemically digested tibiotarsi in the Pd and Pt groups changed by ~45% with respect to the no-injection control (16.1±0.2%). 3) Micro-XRF imaging: Abnormal calcium and phosphorus inclusions were found within the inner longitudinal sections of tibiotarsi for the PGM-mixture treatment. A clear increase in the mineral content was observed for the outer sections of the Pd treatment. 4) ICP-OES: PGM concentrations in tibiotarsi were undetectable (<5ppb). The spectroscopic techniques gave corroborating results, confirmed the hypothesis, and explained the observed pathological (skeletal developmental abnormalities

  7. PLATINUM AND FUEL CELLS

    Science.gov (United States)

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  8. Characterization of electrochemically modified polycrystalline platinum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, L.C.; Ishida, Takanobu.

    1991-12-01

    The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a single potential scan between {minus}0.24 and +1.25 V{sub SCE} while stirring the solution, that the electrocatalytic activity would be regenerated. As a consequence of this study, a much simpler method for producing ultra high purity water from acidic permanganate has been developed. This method results in water that surpasses the water produced by pyrocatalytic distillation. It has also been seen that the wettability of polycrystalline platinum surfaces is greatly dependent on the quantity of oxide present. Oxide-free platinum is hydrophobic and gives a contact angle in the range of 55 to 62 degrees. We have also modified polycrystalline platinum surface with the electrically conducting polymer poly-{rho}-phenylene. This polymer is very stable in dilute sulfuric acid solutions, even under applied oxidative potentials. It is also highly resistant to electrochemical hydrogenation. The wettability of the polymer modified platinum surface is severely dependent on the choice of supporting electrolyte chosen for the electrochemical polymerization. Tetraethylammonium tetrafluoroborate produces a film that is as hydrophobic as Teflon, whereas tetraethylammonium perchlorate produces a film that is more hydrophilic than oxide-free platinum.

  9. Attachment of Free Filament Thermocouples for Temperature Measurements on Ceramic Matrix Composites

    Science.gov (United States)

    Lei, Jih-Fen; Cuy, Michael D.; Wnuk, Stephen P.

    1998-01-01

    At the NASA Lewis Research Center, a new installation technique utilizing convoluted wire thermocouples (TC's) was developed and proven to produce very good adhesion on CMC's, even in a burner rig environment. Because of their unique convoluted design, such TC's of various types and sizes adhere to flat or curved CMC specimens with no sign of delamination, open circuits, or interactions-even after testing in a Mach 0.3 burner rig to 1200 C (2200 F) for several thermal cycles and at several hours at high temperatures. Large differences in thermal expansion between metal thermocouples and low-expansion materials, such as CMC's, normally generate large stresses in the wires. These stresses cause straight wires to detach, but convoluted wires that are bonded with strips of coating allow bending in the unbonded portion to relieve these expansion stresses.

  10. Miniature sheathed thermocouples for turbine blade temperature measurement

    Science.gov (United States)

    Holanda, R.; Glawe, G. E.; Krause, L. N.

    1974-01-01

    An investigation was made of sheathed thermocouples for turbine blade temperature measurements. Tests were performed on the Chromel-Alumel sheathed thermocouples with both two-wire and single-wire configurations. Sheath diameters ranged from 0.25 to 0.76 mm, and temperatures ranged from 1080 to 1250 K. Both steady-state and thermal cycling tests were performed for times up to 450 hr. Special-order and commercial-grade thermocouples were tested. The tests showed that special-order single-wire sheathed thermocouples can be obtained that are reliable and accurate with diameters as small as 0.25 mm. However, all samples of 0.25-mm-diameter sheathed commercial-grade two-wire and single-wire thermocouples that were tested showed unacceptable drift rates for long-duration engine testing programs. The drift rates were about 1 percent in 10 hr. A thermocouple drift test is recommended in addition to the normal acceptance tests in order to select reliable miniature sheathed thermocouples for turbine blade applications.

  11. Bioavailability of very finely distributed metallic platinum in the lungs and first orienting studies on effects. Part 1; Bioverfuegbarkeit von feinstverteiltem metallischem Platin in der Lunge und erste orientierende Wirkungsuntersuchungen (VPT 09; 1. Teil)

    Energy Technology Data Exchange (ETDEWEB)

    Artelt, S. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung, Hannover (Germany)

    1997-12-31

    Projects 07 VPT 08 and 07 VPT 08A revealed that platinum from automotive catalytic converters are largely emitted in metallic form as bound to the support material (aluminium oxide). Platinum emissions from this source are on the order of ng per km. The aim of the still ongoing project 07 VPT 09 is to estimate any health hazards that might grow from the deposition in the human lung by inhalation of very fine platinum particles. To answer this question it is necessary to have sufficient quantities of abraded material at one`s disposal. [Deutsch] Im Rahmen des Projektes 07 VPT 08 und 07 VPT 08A wurde festgestellt, dass Platin aus Automobilabgaskatalysatoren zum ueberwiegenden Teil in metallischer Form, gebunden an Traegermaterial (Aluminiumoxid), emittiert wird. Dabei liegt die Platinemission in der Groessenordnung von ng Platin/km. Im noch laufenden Vorhaben 07 VPT 09 soll ein eventuell auftretendes gesundheitliches Risiko, das durch die inhalative Aufnahme von sehr feinen Platinpartikeln in die Lunge des Menschen entstehen koennte, abgeschaetzt werden. Versuche zur Beantwortung dieser Frage setzen voraus, dass eine genuegend grosse Menge an Abriebmaterial zur Verfuegung steht. (orig.)

  12. Use of miniature, single-wire, sheathed thermocouples

    Science.gov (United States)

    Glawe, G. E.; Holanda, R.; Krause, L. N.

    1977-01-01

    Temperature measurement with small thermocouples is improved by device. Each wire is sheathed separately which increases the interelement insulation by factor of 2 1/2. Each wire in its separate sheath can be brought to junction by independent paths.

  13. Processing Techniques for Correlation of LDA and Thermocouple Signals,

    Science.gov (United States)

    particular when few seeding particles are present in the flow. The thermocouple signal was analog compensated in frequency and the effect of the value of time constant on the velocity temperature correlation was studied.

  14. Catalytic transformations of fatty acids derivatives for food, oleochemicals and fuels over carbon supported platinum group metals

    Energy Technology Data Exchange (ETDEWEB)

    Simakova, I.

    2010-07-01

    prominent in linoleic acid deoxygenation giving only 3 % conversion of fatty acids in 330 min. The deactivation originated from the formation of C17 aromatic compounds and fatty acid dimers via Diels-Alder reaction. Thus hydrogenation of unsaturated fatty acids can be considered as preliminary chemical modification step in the green diesel production. In this work particular care was taken to strengthen the nano level understanding of the Pd role, in particular metal size effect, in the catalytic hydrogenation and deoxygenation. Pd/C catalysts were synthesized with the same Pd loading and systematically varied metal dispersion via the controllable formation of Pd particles over carbon support surface. The effect of metal dispersion on hydrogenation rate and trans/cis ratio was revealed. An optimum metal dispersion giving the highest decarboxylation reaction rate was observed. In addition to the particle size effect, the impact of mass transfer was elucidated and detail discussions on temperature programmed desorption of CO from the fresh and spent samples was provided. Hydrogenation of vegetable feedstocks was performed in batch and continuous modes, using powdered and granulated Pd/C catalysts correspondingly. One of the main focuses of the work was put on the scale-up of the hydrogenation process. There are several challenges attributed to the scale-up of a chemical process which have to be recognized before progressing to an industrial application. In terms of the high production volumes the logical step is to investigate the performance of hydrogenation as a continuous process. A laboratory study in a continuous fixed bed reactor was performed, giving crucial information about the catalyst long-term stability and catalyst deactivation. Furthermore, the impact of using free fatty acids or triglycerides feedstocks as well as the effect of catalyst particle size and Pd loading were investigated in continuous mode. Finally, the production capacities for different operation

  15. Platinum Metal-Free Catalysts for Selective Soft Oxidative Methane → Ethylene Coupling. Scope and Mechanistic Observations.

    Science.gov (United States)

    Peter, Matthias; Marks, Tobin J

    2015-12-09

    Using abundant soft oxidants, a high methane-to-ethylene conversion might be achievable due to the low thermodynamic driving force for over-oxidation. Here we report on the oxidative coupling of methane by gaseous S2 (SOCM). The catalytic properties of Pd/Fe3O4 are compared with those of Fe3O4, and it is found that high ethylene selectivities can be achieved without noble metals; conversion and selectivity on Fe3O4 are stable for at least 48 h at SOCM conditions. SOCM data for 10 oxides are compared, and ethylene selectivities as high as 33% are found; the C2H4/C2H6 ratios of 9-12 observed at the highest S2 conversions are significantly higher than the C2H4/C2H6 ratios usually found in the CH4 coupling with O2. Complementary in-detail analytical studies show that, on Mg, Zr, Sm, W, and La catalysts, which strongly coke during the reaction, lower ethylene selectivities are observed than on Fe, Ti, and Cr catalysts, which only coke to a minor extent. Further catalyst-dependent changes during SOCM in surface area, surface composition, and partial conversion to oxysulfides and sulfides are discussed. Evidence concerning the reaction mechanism is obtained taking into account the selectivity for the different reaction products versus the contact time. CH4 coupling proceeds non-oxidatively with the evolution of H2 on some catalysts, and evidence is presented that C2H4 and C2H2 formation occur via C2H6 and C2H4 dehydrogenation, respectively.

  16. Ages and sources of components of Zn-Pb, Cu, precious metal, and platinum group element deposits in the goodsprings district, clark county, Nevada

    Science.gov (United States)

    Vikre, P.; Browne, Q.J.; Fleck, R.; Hofstra, A.; Wooden, J.

    2011-01-01

    The Goodsprings district, Clark County, Nevada, includes zinc-dominant carbonate replacement deposits of probable late Paleozoic age, and lead-dominant carbonate replacement deposits, copper ?? precious metal-platinum group element (PGE) deposits, and gold ?? silver deposits that are spatially associated with Late Triassic porphyritic intrusions. The district encompasses ??500 km2 although the distribution of all deposits has been laterally condensed by late Mesozoic crustal contraction. Zinc, Pb, and Cu production from about 90 deposits was ??160,000 metric tons (t) (Zn > Pb >> Cu), 2.1 million ounces (Moz) Ag, 0.09 Moz Au, and small amounts of PGEs-Co, V, Hg, Sb, Ni, Mo, Mn, Ir, and U-were also recovered. Zinc-dominant carbonate replacement deposits (Zn > Pb; Ag ?? Cu) resemble Mississippi Valley Type (MVT) Zn-Pb deposits in that they occur in karst and fault breccias in Mississippian limestone where the southern margin of the regional late Paleozoic foreland basin adjoins Proterozoic crystalline rocks of the craton. They consist of calcite, dolomite, sphalerite, and galena with variably positive S isotope compositions (??34S values range from 2.5-13%), and highly radiogenic Pb isotope compositions (206Pb/204Pb >19), typical of MVT deposits above crystalline Precambrian basement. These deposits may have formed when southward flow of saline fluids, derived from basinal and older sedimentary rocks, encountered thinner strata and pinch-outs against the craton, forcing fluid mixing and mineral precipitation in karst and fault breccias. Lead-dominant carbonate replacement deposits (Pb > Zn, Ag ?? Cu ?? Au) occur among other deposit types, often near porphyritic intrusions. They generally contain higher concentrations of precious metals than zinc-dominant deposits and relatively abundant iron oxides after pyrite. They share characteristics with copper ?? precious metal- PGE and gold ?? silver deposits including fine-grained quartz replacement of carbonate minerals in

  17. Modification of the sulphur resistance of platinum by addition of metals for aromatics hydrogenation; Modification de la thioresistance du platine par ajouts d'elements metalliques pour l'hydrogenation d'aromatiques

    Energy Technology Data Exchange (ETDEWEB)

    Guillon, E.

    1999-09-15

    The aim of this study is based on the understanding of sulphur resistance of platinum catalytic systems. In this work, bimetallic systems (Pt-Ge, Pt-Au and Pt-Pd) supported on {gamma}-alumina have been studied. Preparation methods have been chosen to give the best control of the physicochemical properties of final system. Electronic and geometrical properties of the metallic phase were characterised by various techniques (TPR, infrared spectroscopy of adsorbed CO (IR(CO)), EXAFS, LEIS). Ortho-xylene hydrogenation in presence of 100 ppm of sulphur was used as model catalytic test in order to study the sulphur resistance of the catalysts. It has been shown that germanium and palladium act as electro-acceptors toward platinum. The ranking of catalytic activity in presence of sulphur is as followed: Pt-Pd > Pt-Au {approx_equal} Pt >> Pt-Ge {approx_equal} 0. The best sulphur resistance for Pt-Pd was obtained for the composition Pt{sub 20}Pd{sub 80} (Pd/Pt=4). An eggshell PdS structure with Pt (sulfur free) core is proposed. These works show that the sulphur resistance of platinum is not only linked with its electronic properties. They allow us to propose an original concept of sulphur resistant catalyst taking into account each catalytic parameters such as chemical bonding of S and aromatic compounds on the metallic site, physico-chemical characteristics of the bimetallic aggregates (particle size, structure, surface composition) and electronic modification of surface atoms in bimetallic catalysts. (author)

  18. Drift as a Function of Temperature in Platinum-Rhodium-Alloyed Thermoelements

    Science.gov (United States)

    Webster, E. S.; Edler, F.

    2017-02-01

    Platinum-rhodium-alloyed thermocouples are the most commonly used high-temperature reference thermometer in national measurement institutes, second tier laboratories and industry. Despite the common use of these thermocouples, there is still a great deal that is not known about the drift processes that occur in them. Drift processes in these alloys are known to be made up of three main components: crystallographic changes, rhodium oxidation and migration, and contamination. Through careful use, contamination can be largely avoided; however, the other two processes often cannot. Research on drift in the different platinum-rhodium alloys is important because the largest uncertainty component during calibration of these thermocouple types is due to inhomogeneity, and the same mechanisms responsible for inhomogeneity are responsible for the drift. This study investigates the drift processes as a function of temperature and time for the 5 %, 13 %, 17 %, 20 %, 30 % and 40 % Rh alloys when paired with pure platinum. The use of a linear gradient furnace and high-resolution homogeneity scanner has enabled identification of drift characteristics in the temperature range 100°C to 950°C, where the bulk of reversible drift occurs. The experiments have quantified the drift rates and magnitude for thermoelements given two commonly used annealing procedures: the high-temperature quench anneal and the low-temperature vacancy anneal. Consequently, this study provides users of platinum-rhodium thermoelements with guidance on what levels of drift they should expect and exposure times before re-annealing is required. It also shows that a Pt-Rh alloy of 20 % Rh is by far the most stable and has properties comparable to the Pt-Pd thermocouple.

  19. Synthesis and characterization of new platinum(II) and platinum(IV) triphyrin complexes.

    Science.gov (United States)

    Xue, Zhaoli; Kuzuhara, Daiki; Ikeda, Shinya; Okujima, Tetsuo; Mori, Shigeki; Uno, Hidemitsu; Yamada, Hiroko

    2013-02-18

    Metalation of 6,13,20,21-tetrakis(4-methylphenyl)-22H-tribenzo[14]triphyrin(2.1.1) with PtCl(2) gave a platinum(II) complex having a square-planar coordination structure with two pyrrolic nitrogen atoms and two chloride ions, with a saddle-shaped macrocycle. This platinum(II) complex was easily oxidized by air to an octahedral platinum(IV) complex coordinated by three pyrrolic nitrogen atoms as a tridentate monoanionic cyclic ligand and three chloride ions. When platinum(II) triphyrin was crystallized in air, an oxygen atom was incorporated between two α-carbon atoms of the pyrroles as an oxygen bridge to intercept the 14π aromatic system.

  20. Study of supported platinum catalysts by anomalous scattering

    Energy Technology Data Exchange (ETDEWEB)

    Georgopoulos, P.; Cohen, J.B.

    1985-01-01

    Platinum metal catalysts supported on silica gel and alumina were examined by wide-angle anomalous x-ray scattering at the Cornell High Energy Synchrotron Source. Complete removal of the support background features is achieved by this method, eliminating errors due to inaccurate background estimation. Platinum diffraction patterns from very-high-percentage metal-exposed catalysts were obtained for the first time, as well as from platinum supported on alumina. This technique is suitable for examining catalysts under working conditions and is superior to EXAFS for determinations of particle morphology and size distribution. 10 references, 8 figures.

  1. The reliability of thermocouples in microwave ceramics processing.

    Science.gov (United States)

    Aguilar, Juan; Valdez, Zarel; Ortiz, Ubaldo

    2004-01-01

    It is not rare to hear arguments against the use of thermocouples for taking temperatures in processes that are taking place under microwave fields. However, the simplicity of this device makes it attractive to consider its use. One question that arises when thermocouples are employed is whether the electric field perturbs the measurement, and if the thermocouple affects the processing. The process that was chosen for conducting this test was the synthesis of spinel (MgAl2O4) using microwaves as a power supply and hematite (Fe2O3) as an additive for both spinel formation promotion and susceptor. The alumina-based systems are very important to study because this is one of the most common ingredients in refractory materials. There are many discussions about the improvement of the process when microwaves are used, but a kinetic comparison cannot be performed if the temperature is unknown, and that is the reason for emphasizing the measurement techniques. The analysis of the obtained samples was carried out by X-ray diffraction of powders. The results of this work show that there is no difference between the products obtained when the thermocouple was inserted in the system, compared to processing without it; hence the thermocouple is appropriate for this application.

  2. Investigation of the viscous heating artefact arising from the use of thermocouples in a focused ultrasound field.

    Science.gov (United States)

    Morris, Hugh; Rivens, Ian; Shaw, Adam; Haar, Gail Ter

    2008-09-07

    Accurate temperature measurements in therapeutic ultrasound fields are necessary for understanding damage mechanisms, verification of thermal modelling and calibration of non-invasive clinical thermometry. However, artefactual heating, primarily due to viscous forces which result from motion relative to the surrounding tissue, occurs when metal thermocouples are used in an ultrasound field. The magnitude and time dependence of this artefact has been characterized by comparison with novel thin-film thermocouples (TFTs) at 1-2 cm focal depths in fresh degassed ex vivo bovine liver. High-intensity focused ultrasound exposures (1.7 MHz; free-field spatial-peak temporal-average intensities 40-600 W cm(-2)) were used. Subtraction of the TFT data from that obtained for other thermocouples yielded the time dependence of the viscous heating artefact. This was found to be intensity independent up to 600 W cm(-2) (below the threshold for cavitation and lesion formation) and remained significant at radial distances out to the first side lobe in the focal plane. The contribution of viscous heating to cooling was also found to be significant for at least 5 s after the end of insonation. The ratio of viscous artefact to absorptive heating after 5 s was: 1.76 +/- 0.07 for a fine-wire, 0.45 +/- 0.07 and 1.93 +/- 0.07 for two different sheathed-wires and 0.24 +/- 0.07 for a needle thermocouple.

  3. Seebeck Changes Due to Residual Cold-Work and Reversible Effects in Type K Bare-Wire Thermocouples

    Science.gov (United States)

    Webster, E. S.

    2017-09-01

    Type K thermocouples are the most commonly used thermocouple for industrial measurements because of their low cost, wide temperature range, and durability. As with all base-metal thermocouples, Type K is made to match a mathematical temperature-to-emf relationship and not a prescribed alloy formulation. Because different manufacturers use varying alloy formulations and manufacturing techniques, different Type K thermocouples exhibit a range of drift and hysteresis characteristics, largely due to ordering effects in the positive (K+) thermoelement. In this study, these effects are assessed in detail for temperatures below 700°C in the Type K wires from nine manufacturers. A linear gradient furnace and a high-resolution homogeneity scanner combined with the judicious use of annealing processes allow measurements that separately identify the effects of cold-work, ordering, and oxidation to be made. The results show most K+ alloys develop significant errors, but the magnitudes of the contributions of each process vary substantially between the different K+ wires. In practical applications, the measurement uncertainties achievable with Type K therefore depend not only on the wire formulation but also on the temperature, period of exposure, and, most importantly, the thermal treatments prior to use.

  4. Measurements of fluctuating gas temperatures using compensated fine wire thermocouples

    Science.gov (United States)

    Nina, M. N. R.; Pita, G. P.

    1985-09-01

    Thermocouples with three different wire diameters (15, 40 and 50 microns) were used in association with an analog compensation circuit connected to a data acquisition system. Measurements of the time constant were performed using two different heating techniques; Joule effect and external heating by laser beam. The thermocouples were used to quantify the fluctuating temperature field in a hot air jet and in a premixed propane flame. In the reacting case the catalytic effect was evaluated by comparing coated and uncoated wires. Conclusions were also obtained regarding frequency spectra, temperature probability distribution function and time constant.

  5. Platinum single crystal electrodes for the electrocatalysis of methane oxidation

    Directory of Open Access Journals (Sweden)

    Mayara Munaretto

    2011-03-01

    Full Text Available The main objective of this paper is to characterize the voltammetric profiles of platinum single crystals of low Miller indexes Pt(100 and Pt(110 and study their catalytic activities on the oxidation of methane. In this way, it was developed a metallic surface modified by presence of other metal oxide, which presents catalytic activity for this reaction. It is well known that the electrooxidation of methane (CH4 leads mainly to the formation of CO2 and H2O, however, the oxidation can also lead to the formation of CO, a reaction intermediate that has strong interaction with metal surfaces, such as platinum. This molecule tends to accumulate on the platinum surface and to passive it, due to the self-poisoning, decreasing its catalytic activity. Therefore, the main aim of this work was the development of a platinum electrode modified by deposition of titanium oxide, which presented electrocatalytic properties for the oxidation of methane.

  6. Adsorption of volatile polonium species on metals in various gas atmospheres. Pt. II. Adsorption of volatile polonium on platinum, silver and palladium

    Energy Technology Data Exchange (ETDEWEB)

    Maugeri, Emilio Andrea; Joerg Neuhausen; Dressler, Rugard; Piguet, David; Voegele, Alexander; Schumann, Dorothea [Paul Scherrer Institut (PSI), Villigen (Switzerland). Lab. for Radiochemistry; Misiak, Ryszard [The Henryk Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Eichler, Robert [Paul Scherrer Institut (PSI), Villigen (Switzerland). Lab. for Radiochemistry; Bern Univ. (Switzerland). Dept. for Chemistry and Biochemistry

    2016-07-01

    This work presents the results obtained from studying the interaction between polonium compounds formed in different atmospheres and platinum, palladium and silver surfaces obtained by thermochromatography. These results are of crucial importance for the design of cover gas filter systems for lead-bismuth eutectic (LBE)-based nuclear facilities such as accelerator driven systems (ADS). The results obtained from studying the interaction of polonium and platinum under inert atmosphere and reducing atmospheres with and without addition of moisture show that polonium is deposited at temperatures between 993 and 1221 K, with adsorption enthalpies ranging from -235 to -291 kJ mol{sup -1}, indicating a very strong adsorption of the polonium species present on platinum surfaces. The interaction between polonium and silver was investigated using purified inert, reducing and oxidizing carrier gases. Results show a deposition temperature between 867 and 990 K, with adsorption enthalpies ranging from -205 to -234 kJ mol{sup -1}. The interaction of polonium and palladium was studied in purified helium and purified hydrogen. For both conditions a deposition temperature of 1221 K was observed corresponding to an adsorption enthalpy of -340 kJ mol{sup -1}. No highly volatile polonium species was formed at any of the applied experimental conditions.

  7. The influence of platinum washing-out time on its recovery from used auto catalytic converters

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2014-07-01

    Full Text Available The used catalytic converters contain small amounts of precious metals. Recovery of these metals is essential for environmental and economic reasons. This work presents a method of Platinum Group Metals (PGM recovery from auto catalytic converters in which they are washed out by a liquid metal. The magneto-hydro-dynamic pump was used to force circulation of liquid metal under the influence of electromagnetic fields The influence of process time on platinum recovery was also carried out.

  8. Ba 3A2PtCu 2O 10 ( A = Y or Ho): The crystal structure of a reaction by-product of high transition temperature superconductors with platinum metal

    Science.gov (United States)

    Geiser, Urs; Porter, Leigh C.; Wang, Hau H.; Allen, Thomas A.; Williams, Jack M.

    1988-03-01

    Mixtures of CuO, BaCO 3, and A2O 3 ( A = Y, rare earth) react at temperatures between 600 and 1000°C with platinum containers to produce crystals of composition Ba 3A2PtCu 2O 10. The crystal structures of the compounds with A = Y or Ho were determined from single-crystal X-ray diffraction data. They are isostructural, monoclinic, space group {C2}/{m}, with Z = 2. Lattice parameters for Ba 3Y 2PtCu 2O 10 are a = 12.520(3) Å, b = 5.817(1) Å, c = 7.357(1) Å, β = 105.53(2)°, V = 516.2(2) Å 3. Lattice parameters for Ba 3Ho 2PtCu 2O 10 are a = 12.516(3) Å, b = 5.813(1)Å, c = 7.350(3) Å, β = 105.54(2)°, V = 515.2(3)Å 3. The structure of these complex oxides has the four metal ions in five distinct coordination environments: two barium sites with coordination numbers (CN) 8 and 11, yttrium or holmium with CN 7, platinum(IV) with CN 6, and copper with CN 5.

  9. Thermocouples--The Most Widely Used Temperature Sensor in Manufacturing

    Science.gov (United States)

    Mitts, Charles R.

    2006-01-01

    Researchers predict that future developments in nanotechnology will bring incredible, almost inconceivable, change to the manufacturing industry. For now, though, one of technology's most trusted tools remains very relevant: In the field of thermometry, thermocouples are a tried and true technology. As a consequence, material on thermocouples…

  10. Heat penetration and thermocouple location in home canning.

    Science.gov (United States)

    Etzel, Mark R; Willmore, Paola; Ingham, Barbara H

    2015-01-01

    We processed applesauce, tomato juice, and cranberries in pint jars in a boiling water canner to test thermal processing theories against home canning of high-acid foods. For each product, thermocouples were placed at various heights in the jar. Values for f h (heating), f cl (cooling), and F 82.2°C (lethality) were determined for each thermocouple location, and did not depend substantially on thermocouple location in accordance with heat transfer theory. There was a cold spot in the jar, but the cold spot during heating became the hot spot during cooling. During heating, the geometric center was the last to heat, and remained coldest the longest, but during coooling, it was also the last to cool, and remained hottest the longest. The net effect was that calculated lethality in home canning was not affected by thermocouple location. Most of the lethality during home canning occurred during air cooling, making cooling of home canned foods of great importance. Calculated lethality was far greater than the required 5-log reduction of spores in tomato juice and vegetative cells in cranberries, suggesting a wide margin of safety for approved home-canning processes for high-acid foods.

  11. Decomposition of the Precursor [Pt(NH3)4](OH)2, Genesis and Structure of the Metal-Support Interface of Alumina Supported Platinum Particles: A Structural Study Using TPR, MS and XAFS Spectroscopy.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Muñoz-Paez, A.

    1995-01-01

    During the preparation of alumina supported platinum catalysts, the precursor [Pt(NH3)4](OH)2 decomposes to a neutral Pt(NH3)zO species during the drying process at 120 'C. Treatment in flowing hydrogen at 180 'C leads to partial reduction of the platinum ammine complex and formation of platinum met

  12. Development of Mechanical Sealing and Laser Welding Technology to Instrument Thermocouple for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang-Young; Ahn, Sung-Ho; Hong, Jin-Tae; Kim, Ka-Hye; Huh, Sung-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Zircaloy-4 of the nuclear fuel test rod, AISI 316L of the mechanical sealing parts, and the MI (mineral insulated) cable at a thermocouple instrumentation are hetero-metals, and are difficult to weld to dissimilar materials. Therefore, a mechanical sealing method to instrument the thermocouple should be conducted using two kinds of sealing process as follows: One is a mechanical sealing process using Swagelok, which is composed of sealing components that consists of an end-cap, a seal tube, a compression ring and a Swagelok nut. The other is a laser welding process used to join a seal tube, and an MI cable, which are made of the same material. The mechanical sealing process should be sealed up with the mechanical contact compressed by the strength forced between a seal tube and an end-cap, and the laser welding process should be conducted to have no defects on the sealing area between a seal tube and an MI cable. Therefore, the mechanical sealing and laser welding techniques need to be developed to accurately measure the centerline temperature of the nuclear fuel test rod in an experimental reactor. The mechanical sealing and laser welding tests were conducted to develop the thermocouple instrumentation techniques for the nuclear fuel test rod. The optimum torque value of a Swagelok nut to seal the mechanical sealing part between the end-cap and seal tube was established through various torque tests using a torque wrench. The optimum laser welding conditions to seal the welding part between a seal tube and an MI cable were obtained through various welding tests using a laser welding system.

  13. Platinum hypersensitivity and desensitization.

    Science.gov (United States)

    Miyamoto, Shingo; Okada, Rika; Ando, Kazumichi

    2015-09-01

    Platinum agents are drugs used for various types of cancer. With increased frequency of administration of platinum agents, hypersensitivity reactions appear more frequently, occurring in over 25% of cases from the seventh cycle or second line onward. It then becomes difficult to conduct treatment using these agents. Various approaches have been investigated to address hypersensitivity reactions to platinum agents. Desensitization, which gradually increases the concentration of the anticancer drug considered to be the antigen until the target dosage, has been reported as being particularly effective, with a success rate of 80-100%. The aims of this paper are to present the current findings regarding hypersensitivity reactions to platinum agents and to discuss attempts of using desensitization against hypersensitivity reactions worldwide. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. 溶胶-凝胶法制备金属铂高分散的二氧化钛薄膜%Preparation of Titania Thin Film with Highly-Dispersed Platinum Metal by Sol-Gel Method

    Institute of Scientific and Technical Information of China (English)

    黄妙良; 伴隆幸; 大矢丰; 高桥康隆

    2001-01-01

    Uniform and crack-free TiO2 thin films with highly-dispersed platinum were p repared from i-PrOH-TTIP-DEA-H2O system containing H2PtCl6*6H 2O as metal source by sol-gel method. The microstructure and morphology of th e films were characterized by TEM and XRD respectively. It was found that the Pt particles dispersed in the films and had a homogeneous distribution in the shap e of sphere with an average size of about 5 nm. This study also showed that the doping with few percent of Pt resulted in the formation of pure rutile phase at a temperature as low as 550 ℃, whereas the same pure phase was formed at the te mperature higher than 650 ℃ in TiO2 or Au/TiO2 thin films.

  15. Numerical Research of the Measurement Error of Temperature Thermocouples with the Isolated Seal

    OpenAIRE

    Atroshenko Yuliana K.; Bychkova Alena A.; Strizhak Pavel A.

    2015-01-01

    Mathematical models of heattransfer are developed for an assessment of measurement errors of temperature by thermocouples with an isolated and uninsulated seal. Dependences of necessary time of heating (for authentic measurement) for the thermocouples with an isolated seal manufactured of different materials are set. It is shown that for thermocouples with isolated seal minimum necessary duration of heating up slightly exceeds this index for thermocouples with an uninsulated seal.

  16. Interfacial electronic effects control the reaction selectivity of platinum catalysts

    Science.gov (United States)

    Chen, Guangxu; Xu, Chaofa; Huang, Xiaoqing; Ye, Jinyu; Gu, Lin; Li, Gang; Tang, Zichao; Wu, Binghui; Yang, Huayan; Zhao, Zipeng; Zhou, Zhiyou; Fu, Gang; Zheng, Nanfeng

    2016-05-01

    Tuning the electronic structure of heterogeneous metal catalysts has emerged as an effective strategy to optimize their catalytic activities. By preparing ethylenediamine-coated ultrathin platinum nanowires as a model catalyst, here we demonstrate an interfacial electronic effect induced by simple organic modifications to control the selectivity of metal nanocatalysts during catalytic hydrogenation. This we apply to produce thermodynamically unfavourable but industrially important compounds, with ultrathin platinum nanowires exhibiting an unexpectedly high selectivity for the production of N-hydroxylanilines, through the partial hydrogenation of nitroaromatics. Mechanistic studies reveal that the electron donation from ethylenediamine makes the surface of platinum nanowires highly electron rich. During catalysis, such an interfacial electronic effect makes the catalytic surface favour the adsorption of electron-deficient reactants over electron-rich substrates (that is, N-hydroxylanilines), thus preventing full hydrogenation. More importantly, this interfacial electronic effect, achieved through simple organic modifications, may now be used for the optimization of commercial platinum catalysts.

  17. The RSC Faraday prize lecture of 1989 on platinum.

    Science.gov (United States)

    Thomas, John Meurig

    2017-08-25

    In 1861, Michael Faraday gave one of his last Friday Evening Discourses at the Royal Institution of Great Britain, London, on platinum, which he described as "this beautiful, magnificent and valuable metal". More than a hundred and twenty years later (in 1989), the author re-enacted, at the Royal Institution, many of the demonstrations that Faraday carried out in his memorable Discourse. This article outlines many of Faraday's views on, and experiments with, platinum. It also describes the continuing importance and utilization of platinum, both as perceived in 1989 and from present perspectives.

  18. Research on New Technology for Extracting Precious Metals from Low Grade Gold Platinum Palladium Material%从低品位金铂钯物料中提取贵金属新工艺研究

    Institute of Scientific and Technical Information of China (English)

    马玉天; 陈大林; 郭晓辉; 潘从明; 张燕; 王立

    2014-01-01

    金川集团股份有限公司产生的低品位金钯铂物料为蒸残渣,通常是由贵金属精矿蒸馏分离锇、钌,水溶液氯化产生。现有蒸残渣处理工艺为反复氯化,由于受氯化效率的影响,依然有部分贵金属残留在外付渣中,造成贵金属流失。为提高贵金属回收率,金川集团贵金属冶炼厂组织进行了从蒸残渣中提纯贵金属的实验研究。通过长期实验探索,确定了蒸残渣氯化焙烧-盐酸浸出-有机溶剂萃取分离金铂钯的工艺路线。之后,又进行了工业化扩大试验,确定了最佳工艺技术条件,金、铂、钯直收率≥95%。与水溶液氯化工艺相比,该工艺具有贵金属直收率高、劳动强度低、生产周期短及生产成本低等特点。%The company produced platinum and palladium low grade gold material that was a kind of steamed residue,additionally,the steamed residue was produced during the process of precious metals concentrate distillation separation of osmium,ruthenium and aqueous chlorination.The existing steamed residue treatment technique of chloride repeatedly,because the effect of the efficiency of chloride,there were still some precious metal residues in the outside pay residue,has the problem of precious metals lossing.In order to improve the precious metal recovery,the smelting plant in the company completed a series of experimental studies on purification of precious metals from the steamed residue.Thus,after the experimental exploration for a long time, the steamed residue chloridizing roasting-hydrochloric acid leaching gold platinum palladium-organic solvent extraction separation process was determined.Then,the industrialized expanding test and the optimum technology conditions were also determined,meanwhile,the direct recovery rate was more than or equal to 95%during the technological process of gold,platinum and palladium.Compared with aqueous chlorination process,the method applied in the paper

  19. The practical use of thermocouples for temperature measurement in clinical hyperthermia.

    Science.gov (United States)

    Carnochan, P; Dickinson, R J; Joiner, M C

    1986-01-01

    The use of thermocouples as invasive thermometers in clinical hyperthermia is comprehensively and critically reviewed. The ability to construct thermocouple probes as small-bore, multiple junction assemblies is a major reason for their popularity and full constructional details are given. The potential sources of measurement error when using thermocouples both in temperature gradients and in electromagnetic or ultrasonic heating fields are discussed. Emphasis is placed upon simple practical solutions to these problems and a combination of good measurement practice and electrical filtering can reduce errors to an insignificant level. Techniques are suggested for the assessment of thermocouple performance during clinical measurement. With careful use, thermocouples can be reliable and convenient thermometers.

  20. Tungsten-rhenium thin film thermocouples for SiC-based ceramic matrix composites

    Science.gov (United States)

    Tian, Bian; Zhang, Zhongkai; Shi, Peng; Zheng, Chen; Yu, Qiuyue; Jing, Weixuan; Jiang, Zhuangde

    2017-01-01

    A tungsten-rhenium thin film thermocouple is designed and fabricated, depending on the principle of thermal-electric effect caused by the high temperature. The characteristics of thin film thermocouples in different temperatures are investigated via numerical analysis and analog simulation. The working mechanism and thermo-electric features of the thermocouples are analyzed depending on the simulation results. Then the thin film thermocouples are fabricated and calibrated. The calibration results show that the thin film thermocouples based on the tungsten-rhenium material achieve ideal static characteristics and work well in the practical applications.

  1. Platinum recycling going green via induced surface potential alteration enabling fast and efficient dissolution

    Science.gov (United States)

    Hodnik, Nejc; Baldizzone, Claudio; Polymeros, George; Geiger, Simon; Grote, Jan-Philipp; Cherevko, Serhiy; Mingers, Andrea; Zeradjanin, Aleksandar; Mayrhofer, Karl J. J.

    2016-01-01

    The recycling of precious metals, for example, platinum, is an essential aspect of sustainability for the modern industry and energy sectors. However, due to its resistance to corrosion, platinum-leaching techniques rely on high reagent consumption and hazardous processes, for example, boiling aqua regia; a mixture of concentrated nitric and hydrochloric acid. Here we demonstrate that complete dissolution of metallic platinum can be achieved by induced surface potential alteration, an ‘electrode-less' process utilizing alternatively oxidative and reductive gases. This concept for platinum recycling exploits the so-called transient dissolution mechanism, triggered by a repetitive change in platinum surface oxidation state, without using any external electric current or electrodes. The effective performance in non-toxic low-concentrated acid and at room temperature is a strong benefit of this approach, potentially rendering recycling of industrial catalysts, including but not limited to platinum-based systems, more sustainable. PMID:27767178

  2. Platinum recycling going green via induced surface potential alteration enabling fast and efficient dissolution

    Science.gov (United States)

    Hodnik, Nejc; Baldizzone, Claudio; Polymeros, George; Geiger, Simon; Grote, Jan-Philipp; Cherevko, Serhiy; Mingers, Andrea; Zeradjanin, Aleksandar; Mayrhofer, Karl J. J.

    2016-10-01

    The recycling of precious metals, for example, platinum, is an essential aspect of sustainability for the modern industry and energy sectors. However, due to its resistance to corrosion, platinum-leaching techniques rely on high reagent consumption and hazardous processes, for example, boiling aqua regia; a mixture of concentrated nitric and hydrochloric acid. Here we demonstrate that complete dissolution of metallic platinum can be achieved by induced surface potential alteration, an `electrode-less' process utilizing alternatively oxidative and reductive gases. This concept for platinum recycling exploits the so-called transient dissolution mechanism, triggered by a repetitive change in platinum surface oxidation state, without using any external electric current or electrodes. The effective performance in non-toxic low-concentrated acid and at room temperature is a strong benefit of this approach, potentially rendering recycling of industrial catalysts, including but not limited to platinum-based systems, more sustainable.

  3. Catalytic converters as a source of platinum

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2011-10-01

    Full Text Available The increase of Platinum Group Metals demand in automotive industry is connected with growing amount of cars equipped with the catalytic converters. The paper presents the review of available technologies during recycling process. The possibility of removing platinum from the used catalytic converters applying pyrometallurgical and hyrdometallurgical methods were also investigated. Metals such as Cu, Pb, Ca, Mg, Cd were used in the pyrometallurgical research (catalytic converter was melted with Cu, Pb and Ca or Mg and Cd vapours were blown through the whole carrier. In hydrometallurgical research catalytic converters was dissolved in aqua regia. Analysis of Pt contents in the carrier before and after the process was performed by means of atomic absorption spectroscopy. Obtained result were discussed.

  4. Evaluation of Thermocouple Temperature Sensors in a Simulated Mars Environment

    Science.gov (United States)

    Sykulska-Lawrence, Hanna; Mansell, J.; Bowles, N.; Calcutt, S.; Temple, J.

    2010-10-01

    The Martian environment is meteorologically extremely dry, dusty, cold (with a large diurnal temperature change), is irradiated by UV and is probably highly chemically oxidising. Detailed measurements of the near-surface atmospheric temperature profile coupled with other meteorological data allow the dynamics of the Martian atmospheric boundary layer to be investigated. This is of particular importance given the atmosphere's tendency to turbulent mixing observed by previous experiments, on e.g. Mars Pathfinder within a few metres of the surface. We examine thermocouple sensors for the Mars environment by evaluating the sensor designed for the AEP instrument, a meteorology package previously selected for the ExoMars geophysics lander. The design of the sensor contains three thin wire thermocouples for redundancy in a configuration based on those flown on the Viking, Mar Pathfinder and Phoenix landers. Thin-wire thermocouples offer the best type of temperature sensor for in-situ atmospheric temperature measurements as they have a fast response time, are less sensitive to radiative heat coupling and do not have problems with self-heating. The sensor described in this presentation is accurate to < 0.25K. The work presented will describe the sensor itself and provide results of detailed calibration tests in an isothermal Mars environmental chamber (simulating the temperatures, pressure and atmospheric composition expected near the surface) testing the instruments accuracy, and response in relation to the thermal capacity of the wire. Further to this, numerical models used to investigate the difficulties in correctly measuring the temperature of the atmosphere will be described. These models consider effects such as radiative heating from direct sunlight or radiation reflected from the surface, shielding from flowing air. Having studied the behaviour of this sensor and different types of design of thermocouple weld, including re-examining the Viking sensors, if

  5. Toxicity of platinum compounds.

    Science.gov (United States)

    Hartmann, Jörg Thomas; Lipp, Hans-Peter

    2003-06-01

    Since the introduction of platinum-based combination chemotherapy, particularly cisplatin, the outcome of the treatment of many solid tumours has changed. The leading platinum compounds in cancer chemotherapy are cisplatin, carboplatin and oxaliplatin. They share some structural similarities; however, there are marked differences between them in therapeutic use, pharmacokinetics and adverse effects profiles [1-4]. Compared to cisplatin, carboplatin has inferior efficacy in germ-cell tumour, head and neck cancer and bladder and oesophageal carcinoma, whereas both drugs seem to have comparable efficacy in advanced non-small cell and small cell lung cancer as well as ovarian cancer [5-7]. Oxaliplatin belongs to the group of diaminocyclohexane platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid [8,9]. Other platinum compounds such as oral JM216, ZD0473, BBR3464 and SPI-77, which is a pegylated liposomal formulation of cisplatin, are still under investigation [10-13], whereas nedaplatin has been approved in Japan for the treatment of non-small cell lung cancer and other solid tumours. This review focuses on cisplatin, carboplatin and oxaliplatin.

  6. Evaluation of piecewise polynomial equations for two types of thermocouples.

    Science.gov (United States)

    Chen, Andrew; Chen, Chiachung

    2013-12-12

    Thermocouples are the most frequently used sensors for temperature measurement because of their wide applicability, long-term stability and high reliability. However, one of the major utilization problems is the linearization of the transfer relation between temperature and output voltage of thermocouples. The linear calibration equation and its modules could be improved by using regression analysis to help solve this problem. In this study, two types of thermocouple and five temperature ranges were selected to evaluate the fitting agreement of different-order polynomial equations. Two quantitative criteria, the average of the absolute error values |e|(ave) and the standard deviation of calibration equation e(std), were used to evaluate the accuracy and precision of these calibrations equations. The optimal order of polynomial equations differed with the temperature range. The accuracy and precision of the calibration equation could be improved significantly with an adequate higher degree polynomial equation. The technique could be applied with hardware modules to serve as an intelligent sensor for temperature measurement.

  7. Evaluation of Piecewise Polynomial Equations for Two Types of Thermocouples

    Directory of Open Access Journals (Sweden)

    Andrew Chen

    2013-12-01

    Full Text Available Thermocouples are the most frequently used sensors for temperature measurement because of their wide applicability, long-term stability and high reliability. However, one of the major utilization problems is the linearization of the transfer relation between temperature and output voltage of thermocouples. The linear calibration equation and its modules could be improved by using regression analysis to help solve this problem. In this study, two types of thermocouple and five temperature ranges were selected to evaluate the fitting agreement of different-order polynomial equations. Two quantitative criteria, the average of the absolute error values |e|ave and the standard deviation of calibration equation estd, were used to evaluate the accuracy and precision of these calibrations equations. The optimal order of polynomial equations differed with the temperature range. The accuracy and precision of the calibration equation could be improved significantly with an adequate higher degree polynomial equation. The technique could be applied with hardware modules to serve as an intelligent sensor for temperature measurement.

  8. Monofunctional and Higher-Valent Platinum Anticancer Agents

    Science.gov (United States)

    Johnstone, Timothy C.; Wilson, Justin J.

    2013-01-01

    Platinum compounds represent one of the great success stories of metals in medicine. Following the serendipitous discovery of the anticancer activity of cisplatin by Rosenberg, a large number of cisplatin variants have been prepared and tested for their ability to kill cancer cells and inhibit tumor growth. These efforts continue today with increased realization that new strategies are needed to overcome issues of toxicity and resistance inherent to treatment by the approved platinum anticancer agents. One approach has been the use of so-called “non-traditional” platinum(II) and platinum(IV) compounds that violate the structure-activity relationships that governed platinum drug-development research for many years. Another is the use of specialized drug delivery strategies. Here we describe recent developments from our laboratory involving monofunctional platinum(II) complexes together with an historical account of the manner by which we came to investigate these compounds and their relationship to previously studied molecules. We also discuss work carried out using platinum(IV) prodrugs and the development of nanoconstructs designed to deliver them in vivo. PMID:23738524

  9. Enhancements to High Temperature In-Pile Thermocouple Performance

    Energy Technology Data Exchange (ETDEWEB)

    J. C. Crepeau; J. L. Rempe; J. E. Daw; D. L. Knudson; K. G. Condie; S. C. Wilkins

    2008-03-01

    A joint University of Idaho (UI) and Idaho National Laboratory (INL) University Nuclear Research Initiative (UNERI) was to initiated to extend initial INL efforts to develop doped lybdenum/niobium alloy High Temperature Irradiation Resistant Thermocouples (HTIR-TCs). The overall objective of this UNERI was to develop recommendations for an optimized thermocouple design for high temperature, long duration, in-pile testing by expanding upon results from initial INL efforts. Tasks to quantify the impact of candidate enhancements, such as alternate alloys, alternate geometries, and alternate thermocouple fabrication techniques, on thermocouple performance were completed at INL's High Temperature Test Laboratory (HTTL), a state of the art facility equipped with specialized equipment and trained staff in the area of high temperature instrumentation development and evaluation. Key results of these evaluations, which are documented in this report, are as follows. The doped molybdenum and Nb-1%Zr, which were proposed in the initial INL HTIR-TC design, were found to retain ductility better than the developmental molybdenum-low niobium alloys and the niobium-low molybdenum alloys evaluated. Hence, the performance and lower cost of the commercially available KW-Mo makes a thermocouple containing KW-Mo and Nb-1%Zr the best option at this time. HTIR-TCs containing larger diameter wires offer the potential to increase HTIR-TC stability and reliability at higher temperatures. HTIR-TC heat treatment temperatures and times should be limited to not more than 100 °C above the proposed operating temperatures and to durations of at least 4 to 5 hours. Preliminary investigations suggest that the performance of swaged and loose assembly HTIR-TC designs is similar. However, the swaged designs are less expensive and easier to construct. In addition to optimizing HTIR-TC performance, This UNERI project provided unique opportunities to several University of Idaho students, allowing them

  10. Enhancements to High Temperature In-Pile Thermocouple Performance

    Energy Technology Data Exchange (ETDEWEB)

    J.C. Crepeau; J.L. Rempe; J.E. Daw; D.L. Knudson: K.G. Condie; S.C. Wilkins

    2008-03-31

    A joint University of Idaho (UI) and Idaho National Laboratory (INL) University Nuclear Research Initiative (UNERI) was to initiated to extend initial INL efforts to develop doped molybdenum/niobium alloy High Temperature Irradiation Resistant Thermocouples (HTIR-TCs). The overall objective of this UNERI was to develop recommendations for an optimized thermocouple design for high temperature, long duration, in-pile testing by expanding upon results from initial INL efforts. Tasks to quantify the impact of candidate enhancements, such as alternate alloys, alternate geometries, and alternate thermocouple fabrication techniques, on thermocouple performance were completed at INL's High Temperature Test Laboratory (HTTL), a state of the art facility equipped with specialized equipment and trained staff in the area of high temperature instrumentation development and evaluation. Key results of these evaluations, which are documented in this report, are as follows. The doped molybdenum and Nb-1%Zr, which were proposed in the initial INL HTIR-TC design, were found to retain ductility better than the developmental molybdenum-low niobium alloys and the niobium-low molybdenum alloys evaluated. Hence, the performance and lower cost of the commercially available KW-Mo makes a thermocouple containing KW-Mo and Nb-1%Zr the best option at this time. HTIR-TCs containing larger diameter wires offer the potential to increase HTIR-TC stability and reliability at higher temperatures. HTIR-TC heat treatment temperatures and times should be limited to not more than 100 C above the proposed operating temperatures and to durations of at least 4 to 5 hours. Preliminary investigations suggest that the performance of swaged and loose assembly HTIR-TC designs is similar. However, the swaged designs are less expensive and easier to construct. In addition to optimizing HTIR-TC performance, This UNERI project provided unique opportunities to several University of Idaho students, allowing them

  11. Comparisons of Gas-phase Temperature Measurements in a Flame Using Thin-Filament Pyrometry and Thermocouples

    Science.gov (United States)

    Struk, Peter; Dietrich, Daniel; Valentine, Russell; Feier, Ioan

    2003-01-01

    Less-intrusive, fast-responding, and full-field temperature measurements have long been a desired tool for the research community. Recently, the emission of a silicon-carbide (SiC) fiber placed in a flowing hot (or reacting) gas has been used to measure the temperature profile along the length of the fiber. The relationship between the gas and fiber temperature comes from an energy balance on the fiber. In the present work, we compared single point flame temperature measurements using thin-filament pyrometry (TFP) and thermocouples. The data was from vertically traversing a thermocouple and a SiC fiber through a methanol/air diffusion flame of a porous-metal wick burner. The results showed that the gas temperature using the TFP technique agreed with the thermocouple measurements (25.4 m diameter wire) within 3.5% for temperatures above 1200 K. Additionally, we imaged the entire SiC fiber (with a spatial resolution of 0.14 mm) while it was in the flame using a high resolution CCD camera. The intensity level along the fiber length is a function of the temperature. This results in a one-dimensional temperature profiles at various heights above the burner wick. This temperature measurement technique, while having a precision of less than 1 K, showed data scatter as high as 38 K. Finally, we discuss the major sources of uncertainty in gas temperature measurement using TFP.

  12. Oxygen Reduction on Platinum

    DEFF Research Database (Denmark)

    Nesselberger, Markus

    This thesis investigates the electro reduction of oxygen on platinum nanoparticles, which serve as catalyst in low temperature fuel cells. Kinetic studies on model catalysts as well as commercially used systems are presented in order to investigate the particle size effect, the particle proximity...... carbon (HSAC) supported Pt nanoparticle (Pt/C) catalysts (of various size between 1 and 5 nm). The difference in SA between the individual Pt/C catalysts (1 to 5 nm) is very small and within the error of the measurements. The factor four of loss in SA when comparing platinum bulk and Pt/C can largely...

  13. Peltier effect exchanges in contact thermocouples - Application to the characterization of new thermoelectric circuits

    Science.gov (United States)

    Berrached, N.-E.

    Results from an investigation of coupling in thermoelectric circuits manufactured by electrodeposition of a metallic conductor on a conducting foil made of a different material are presented. The study was undertaken to define the significant factors in the design and manufacture of thermal fluxmeters. Theoretical considerations indicate that the voltage appearing between output connections is proportional to the average spatial thermal gradient on the sensitive surface of the thermoelement. A figure of merit is defined for the coupling of the contact thermocouples. Localized thermal exchanges of opposite sign are shown to occur due to the passage of current, and are concentrated at the boundaries of each thermoelement. Nonisothermal tangential thermal gradients appear on the surface of the circuit. Experimental studies confirm the appearance of the gradients by their IR signatures. Finally, the gradients are determined to be affected by the thickness and conductivity of the medium placed between the emitter and detector circuits.

  14. In vitro permeation of platinum and rhodium through Caucasian skin.

    Science.gov (United States)

    Franken, A; Eloff, F C; Du Plessis, J; Badenhorst, C J; Jordaan, A; Du Plessis, J L

    2014-12-01

    During platinum group metals (PGMs) refining the possibility exists for dermal exposure to PGM salts. The dermal route has been questioned as an alternative route of exposure that could contribute to employee sensitisation, even though literature has been focused on respiratory exposure. This study aimed to investigate the in vitro permeation of platinum and rhodium through intact Caucasian skin. A donor solution of 0.3mg/ml of metal, K2PtCl4 and RhCl3 respectively, was applied to the vertical Franz diffusion cells with full thickness abdominal skin. The receptor solution was removed at various intervals during the 24h experiment, and analysed with high resolution ICP-MS. Skin was digested and analysed by ICP-OES. Results indicated cumulative permeation with prolonged exposure, with a significantly higher mass of platinum permeating after 24h when compared to rhodium. The mass of platinum retained inside the skin and the flux of platinum across the skin was significantly higher than that of rhodium. Permeated and skin retained platinum and rhodium may therefore contribute to sensitisation and indicates a health risk associated with dermal exposure in the workplace.

  15. Biomineralization of platinum by microorganisms

    Science.gov (United States)

    Pavlova, L. M.; Radomskaya, V. I.; Shumilova, L. P.; Ionov, A. M.; Sorokin, P.

    2017-04-01

    The mechanism of platinum biomineralization by microscopic fungi is displayed based on data of electron microscopy, infrared and X-ray photoelectronic spectroscopy. It was suggested the platinum sorption process by microscopic fungi has some stages. The initial interaction is carried out by the mechanisms of physical and chemical sorption. Hereafter the reduction process of adsorbed platinum ions up to zero state is performed, probably, for account of organic compounds, which are produced by fungi biomass as metabolism result, and the process terminates by nulvalent particles aggregating up to nanosize forms. Obtained data on the platinum biomineralization extends the concept concerning the character of forming platinum nanoparticles in carbonous paleobasin.

  16. Interaction of DNA with Bis(diiminosuccinonitrilo)platinum(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Gang; SUN Yuan-Yuan; JIANG Xiao-Ming

    2008-01-01

    Interaction of DNA with bis(diiminosuccinonitrilo)platinum(Ⅱ) has been studied by UV-visible absorbance spectra, fluorescence spectra and viscosity measurements. The UV-visible absorption spectra of the metal complex exhibit hypochromism with a small blue shift on interaction with DNA. Scatchard plot analyses indicate that the binding sites of the metal complex on DNA are different from those of ethidium bromide. Viscosity experiments reveal that the binding of the metal complex decreases the relative viscosity of DNA. These results suggest that the platinum diimine complex interact with DNA by surface binding. These studies are helpful for us to understand the action mechanism of bis(diiminosuccinonitrilo)platinum(Ⅱ) as a potential photodynamic therapeutic agent, and further to develop it.

  17. Platinum blue staining of cells grown in electrospun scaffolds.

    Science.gov (United States)

    Yusuf, Mohammed; Millas, Ana Luiza G; Estandarte, Ana Katrina C; Bhella, Gurdeep K; McKean, Robert; Bittencourt, Edison; Robinson, Ian K

    2014-01-01

    Fibroblast cells grown in electrospun polymer scaffolds were stained with platinum blue, a heavy metal stain, and imaged using scanning electron microscopy. Good contrast on the cells was achieved compared with samples that were gold sputter coated. The cell morphology could be clearly observed, and the cells could be distinguished from the scaffold fibers. Here we optimized the required concentration of platinum blue for imaging cells grown in scaffolds and show that a higher concentration causes platinum aggregation. Overall, platinum blue is a useful stain for imaging cells because of its enhanced contrast using scanning electron microscopy (SEM). In the future it would be useful to investigate cell growth and morphology using three-dimensional imaging methods.

  18. Characterization of a Method for Inverse Heat Conduction Using Real and Simulated Thermocouple Data

    Science.gov (United States)

    Pizzo, Michelle E.; Glass, David E.

    2017-01-01

    It is often impractical to instrument the external surface of high-speed vehicles due to the aerothermodynamic heating. Temperatures can instead be measured internal to the structure using embedded thermocouples, and direct and inverse methods can then be used to estimate temperature and heat flux on the external surface. Two thermocouples embedded at different depths are required to solve direct and inverse problems, and filtering schemes are used to reduce noise in the measured data. Accuracy in the estimated surface temperature and heat flux is dependent on several factors. Factors include the thermocouple location through the thickness of a material, the sensitivity of the surface solution to the error in the specified location of the embedded thermocouples, and the sensitivity to the error in thermocouple data. The effect of these factors on solution accuracy is studied using the methodology discussed in the work of Pizzo, et. al.1 A numerical study is performed to determine if there is an optimal depth at which to embed one thermocouple through the thickness of a material assuming that a second thermocouple is installed on the back face. Solution accuracy will be discussed for a range of embedded thermocouple depths. Moreover, the sensitivity of the surface solution to (a) the error in the specified location of the embedded thermocouple and to (b) the error in the thermocouple data are quantified using numerical simulation, and the results are discussed.

  19. Behaviour of palladium(II), platinum(IV), and rhodium(III) in artificial and natural waters: influence of reactor surface and geochemistry on metal recovery.

    Science.gov (United States)

    Cobelo-Garcia, Antonio; Turner, Andrew; Millward, Geoffrey E; Couceiro, Fay

    2007-03-07

    The recovery of dissolved platinum group elements (PGE: Pd(II), Pt(IV) and Rh(III)) added to Milli-Q water, artificial freshwater and seawater and filtered natural waters has been studied, as a function of pH and PGE concentration, in containers of varying synthetic composition. The least adsorptive and/or precipitative loss was obtained for borosilicate glass under most of the conditions employed, whereas the greatest loss was obtained for low-density polyethylene. Of the polymeric materials tested, the adsorptive and/or precipitative loss of PGE was lowest for fluorinated ethylene propylene (Teflon). The loss of Pd(II) in freshwater was significant due to its affinity for surface adsorption and its relatively low solubility. The presence of natural dissolved organic matter increases the recovery of Pd(II) but enhances the loss of Pt(IV). The loss of Rh(III) in seawater was significant and was mainly due to precipitation, whereas Pd(II) recovery was enhanced, compared to freshwater, because of its complexation with chloride. The results have important implications regarding protocols employed for sample preservation and controlled laboratory experiments used in the study of the speciation and biogeochemical behaviour of PGE.

  20. Addition of platinum and silver nanoparticles to toughen dental porcelain.

    Science.gov (United States)

    Fujieda, Tokushi; Uno, Mitsunori; Ishigami, Hajime; Kurachi, Masakazu; Wakamatsu, Nobukazu; Doi, Yutaka

    2012-01-01

    Several studies have investigated toughening porcelain that is layered over a frame or a core. The introduction of residual compressive stress to the surface of porcelain has been shown to be effective to strengthen it. In the present study, nanoparticles of precious metals of silver and platinum (rather than non-precious metals) were used to evaluate if they could increase the fracture resistance of porcelain. The addition of silver and platinum nanoparticles was found to improve the mechanical properties of porcelain since it increased both the Young's modulus and the fracture toughness of commercial porcelain.

  1. Heat Flux estimation in WEST divertor with embedded thermocouples

    Science.gov (United States)

    Gaspar, J.; Corre, Y.; Firdaouss, M.; Gardarein, J.-L.; Guilhem, D.; Houry, M.; Le Niliot, C.; Missirlian, M.; Pocheau, C.; Rigollet, F.

    2016-09-01

    The present paper deals with the surface heat flux estimation with embedded thermocouples (TC) in a Plasma Facing Component (PFC) of the WEST Tokamak. A 2D nonlinear unsteady calculation combined with the Conjugate Gradient Method (CGM) and the adjoint state is achieved in order to estimate the time evolution of the heat flux amplitude and decay length λq . The method is applied on different synthetic measurements in order to evaluate the accuracy of the method. The synthetic measurements are generated with realistic values of λq and magnitudes as those expected for ITER.

  2. Recent improvements on micro-thermocouple based SThM

    Science.gov (United States)

    Nguyen, TP; Thiery, L.; Teyssieux, D.; Briand, D.; Vairac, P.

    2017-01-01

    The scanning thermal microscope (SThM) has become a versatile tool for local surface temperature mapping or measuring thermal properties of solid materials. In this article, we present recent improvements in a SThM system, based on a micro-wire thermocouple probe associated with a quartz tuning fork for contact strength detection. Some results obtained on an electrothermal micro-hotplate device, operated in active and passive modes, allow demonstrating its performance as a coupled force detection and thermal measurement system.

  3. Temporary Thermocouple Attachment for Thermal/Vacuum Testing at Non-Extreme Temperatures

    Science.gov (United States)

    Ungar, Eugene K.; Wright, Sarah E.

    2016-01-01

    Post-test examination and data analysis that followed a two week long vacuum test showed that numerous self-stick thermocouples became detached from the test article. The thermocouples were reattached with thermally conductive epoxy and the test was repeated to obtain the required data. Because the thermocouple detachment resulted in significant expense and rework, it was decided to investigate the temporary attachment methods used around NASA and to perform a test to assess their efficacy. The present work describes the original test and the analysis that showed that the thermocouples had become detached, temporary thermocouple attachment methods assessed in the retest and in the thermocouple attachment test, and makes a recommendation for attachment methods for future tests.

  4. Bio-inspired routes for synthesizing efficient nanoscale platinum electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jennifer N. [Univ. of California, San Diego, CA (United States); Wang, Joseph [Univ. of California, San Diego, CA (United States)

    2014-08-31

    controlled, the nanocrystals boast a defined shape, morphology, orientation and size and are synthesized at benign reaction conditions. Adapting the methods of biomineralization towards the synthesis of platinum nanocrystals will allow effective control at a molecular level of the synthesis of highly active metal electrocatalysts, with readily tailored properties, through tuning of the biochemical inputs. The proposed research will incorporate many facets of biomineralization by: (1) isolating peptides that selectively bind particular crystal faces of platinum (2) isolating peptides that promote the nucleation and growth of particular nanocrystal morphologies (3) using two-dimensional DNA scaffolds to control the spatial orientation and density of the platinum nucleating peptides, and (4) combining bio-templating and soluble peptides to control crystal nucleation, orientation, and morphology. The resulting platinum nanocrystals will be evaluated for their electrocatalytic behavior (on common carbon supports) to determine their optimal size, morphology and crystal structure. We expect that such rational biochemical design will lead to highly uniform and efficient platinum nanocrystal catalysts for fuel cell applications.

  5. Synthesis of Bimetallic Platinum Nanoparticles for Biosensors

    Directory of Open Access Journals (Sweden)

    Gerard M. Leteba

    2013-08-01

    Full Text Available The use of magnetic nanomaterials in biosensing applications is growing as a consequence of their remarkable properties; but controlling the composition and shape of metallic nanoalloys is problematic when more than one precursor is required for wet chemistry synthesis. We have developed a successful simultaneous reduction method for preparation of near-spherical platinum-based nanoalloys containing magnetic solutes. We avoided particular difficulties in preparing platinum nanoalloys containing Ni, Co and Fe by the identification of appropriate synthesis temperatures and chemistry. We used transmission electron microscopy (TEM to show that our particles have a narrow size distribution, uniform size and morphology, and good crystallinity in the as-synthesized condition. Energy dispersive spectroscopy (EDS and X-ray diffraction (XRD confirms the coexistence of Pt with the magnetic solute in a face-centered cubic (FCC solid solution.

  6. New water-soluble azido- and derived tetrazolato-platinum(II) complexes with PTA. Easy metal-mediated synthesis and isolation of 5-substituted tetrazoles.

    Science.gov (United States)

    Smoleński, Piotr; Mukhopadhyay, Suman; Guedes da Silva, M Fátima C; Charmier, M Adília Januário; Pombeiro, Armando J L

    2008-12-14

    The water-soluble four- and five-coordinate diazido-platinum(II) complexes cis-[Pt(N3)2(PTA)2] (1) (PTA = 1,3,5-triaza-7-phosphaadamantane), cis-[Pt(N3)2(Me-PTA)2]I2 (2) (Me-PTA = N-methyl-1,3,5-triaza-7-phosphaadamantane cation) and [Pt(N3)2(PTA)3] (3) were obtained by reactions of cis-[Pt(N3)2(PPh3)2] with PTA or [Me-PTA]I in dichloromethane. [2 + 3] cycloadditions of with organonitriles NCR gave the bis(tetrazolato) complexes trans-[Pt(N4CR)2(PTA)2] (R = Ph (4), 4-ClC6H4 (5) or 3-NC5H4 (6)), the reactions being greatly accelerated by microwave irradiation. 5-R-1H-Tetrazoles N4CR (R = Ph, 4-ClC6H4 and 3-NC5H4) were easily liberated from the tetrazolato complexes and isolated in high yields, in a single-pot process, upon reaction with aqueous diluted HCl, with concomitant formation of the water soluble cis-[Pt(Cl)2(PTA-H)2] complex 7. Alternatively, in a less convenient method, the tetrazoles could be liberated on reaction of 4-6 with propionitrile which also leads to the dicyano trans-[Pt(CN)2(PTA)2] complex 8. The compounds were characterized by IR, 1H, 13C and 31P[1H] NMR spectroscopies, FAB+-MS or ESI-MS, elemental analyses and (for and 4) also by X-ray diffraction.

  7. Heat flux measurements on ceramics with thin film thermocouples

    Science.gov (United States)

    Holanda, Raymond; Anderson, Robert C.; Liebert, Curt H.

    1993-01-01

    Two methods were devised to measure heat flux through a thick ceramic using thin film thermocouples. The thermocouples were deposited on the front and back face of a flat ceramic substrate. The heat flux was applied to the front surface of the ceramic using an arc lamp Heat Flux Calibration Facility. Silicon nitride and mullite ceramics were used; two thicknesses of each material was tested, with ceramic temperatures to 1500 C. Heat flux ranged from 0.05-2.5 MW/m2(sup 2). One method for heat flux determination used an approximation technique to calculate instantaneous values of heat flux vs time; the other method used an extrapolation technique to determine the steady state heat flux from a record of transient data. Neither method measures heat flux in real time but the techniques may easily be adapted for quasi-real time measurement. In cases where a significant portion of the transient heat flux data is available, the calculated transient heat flux is seen to approach the extrapolated steady state heat flux value as expected.

  8. Inhibition of Aβ42 peptide aggregation by a binuclear ruthenium(II)-platinum(II) complex: Potential for multi-metal organometallics as anti-amyloid agents.

    Science.gov (United States)

    Kumar, Amit; Moody, Lamaryet; Olaivar, Jason F; Lewis, Nerissa A; Khade, Rahul L; Holder, Alvin A; Zhang, Yong; Rangachari, Vijayaraghavan

    2010-08-23

    Design of inhibitors for amyloid-β (Aβ) peptide aggregation has been widely investigated over the years towards developing viable therapeutic agents for Alzheimer's disease (AD). The biggest challenge seems to be inhibiting Aβ aggregation at the early stages of aggregation possibly at the monomeric level, as oligomers are known to be neurotoxic. In this regard, exploiting the metal chelating property of Aβ to generate molecules that can overcome this impediment presents some promise. Recently, one such metal complex containing Pt(II) ([Pt(BPS)Cl(2)]) was reported to effectively inhibit Aβ42 aggregation and toxicity (1). This complex was able bind to Aβ42 at the N-terminal part of the peptide and triggered a conformational change resulting in effective inhibition. In the current report, we have generated a mixed-binuclear metal complex containing Pt(II) and Ru(II) that inhibited Aβ42 aggregation at an early stage of aggregation and seemed to have different modes of interaction than the previously reported Pt(II) complex, suggesting an important role of the second metal center. This 'proof-of-concept' compound will help in developing more effective molecules against Aβ aggregation by modifying the two metal centers as well as their ligands, which will open doors to new rationale for Aβ inhibition.

  9. Size-dependent metal-insulator transition in platinum-dispersed silicon dioxide thin film: A candidate for future non-volatile memory

    Science.gov (United States)

    Chen, Albert B. K.

    Non-volatile random access memories (NVRAM) are promising data storage and processing devices. Various NVRAM, such as FeRAM and MRAM, have been studied in the past. But resistance switching random access memory (RRAM) has demonstrated the most potential for replacing flash memory in use today. In this dissertation, a novel RRAM material design that relies upon an electronic transition, rather than a phase change (as in chalcogenide Ovonic RRAM) or a structural change (such in oxide and halide filamentary RRAM), is investigated. Since the design is not limited to a single material but applicable to general combinations of metals and insulators, the goal of this study is to use a model material to delineate the intrinsic features of the electronic metal/insulator transition in random systems and to demonstrate their relevance to reliable memory storage and retrieval. We fabricated amorphous SiO2 thin films embedded with randomly dispersed Pt atoms. Macroscopically, this random material exhibits a percolation transition in electric conductivity similar to the one found in various insulator/metal granular materials. However, at Pt concentrations well below the bulk percolation limit, a distinct insulator to metal transition occurs in the thickness direction as the film thickness falls below electron's "diffusion" distance, which is the tunneling distance at 0K. The thickness-triggered metal- to-insulator transition (MIT) can be similarly triggered by other conditions: (a) a changing Pt concentration (a concentration-triggered MIT), (b) a changing voltage/polarity (voltage-triggered MIT), and (c) an UV irradiation (photon-triggered MIT). The resistance switching characteristics of this random material were further investigated in several device configurations under various test conditions. These include: materials for the top and bottom electrodes, fast pulsing, impedance spectroscopy, static stressing, retention, fatigue and temperature from 10K to 448K. The SiO2-Pt

  10. Platinum in Earth surface environments

    Science.gov (United States)

    Reith, F.; Campbell, S. G.; Ball, A. S.; Pring, A.; Southam, G.

    2014-04-01

    Platinum (Pt) is a rare precious metal that is a strategic commodity for industries in many countries. The demand for Pt has more than doubled in the last 30 years due to its role in the catalytic conversion of CO, hydrocarbons and NOx in modern automobiles. To explore for new Pt deposits, process ores and deal with ecotoxicological effects of Pt mining and usage, the fundamental processes and pathways of Pt dispersion and re-concentration in surface environments need to be understood. Hence, the aim of this review is to develop a synergistic model for the cycling of Pt in Earth surface environments. This is achieved by integrating the geological/(biogeo)chemical literature, which focuses on naturally occurring Pt mobility around ore deposits, with the environmental/ecotoxicological literature dealing with anthropogenic Pt dispersion. In Pt deposits, Pt occurs as sulfide-, telluride- and arsenide, native metal and alloyed to other PGEs and iron (Fe). Increased mining and utilization of Pt combined with the burning of fossil fuels have led to the dispersion of Pt-containing nano- and micro-particles. Hence, soils and sediments in industrialized areas, urban environments and along major roads are now commonly Pt enriched. Platinum minerals, nuggets and anthropogenic particles are transformed by physical and (bio)geochemical processes. Complexation of Pt ions with chloride, thiosulfate, ammonium, cyanide, low- and high molecular weight organic acids (LMWOAs and HMWOAs) and siderophores can facilitate Pt mobilization. Iron-oxides, clays, organic matter and (micro)biota are known to sequester Pt-complexes and -particles. Microbes and plants are capable of bioaccumulating and reductively precipitating mobile Pt complexes. Bioaccumulation can lead to toxic effects on plants and animals, including humans. (Bio)mineralization in organic matter-rich sediments can lead to the formation of secondary Pt particles and -grains. Ultimately, Pt is enriched in oceanic sediments

  11. Development of a Sheathed Miniature Aerothermal Reentry Thermocouple for Thermal Protection System Materials

    Science.gov (United States)

    Martinez, Edward R.; Weber, Carissa Tudryn; Oishi, Tomo; Santos, Jose; Mach, Joseph

    2011-01-01

    The Sheathed Miniature Aerothermal Reentry Thermocouple is a micro-miniature thermocouple for high temperature measurement in extreme environments. It is available for use in Thermal Protection System materials for ground testing and flight. This paper discusses the heritage, and design of the instrument. Experimental and analytical methods used to verify its performance and limitations are described.

  12. Localization of focused-ultrasound beams in a tissue phantom, using remote thermocouple arrays.

    Science.gov (United States)

    Hariharan, Prasanna; Dibaji, Seyed Ahmad Reza; Banerjee, Rupak K; Nagaraja, Srinidhi; Myers, Matthew R

    2014-12-01

    In focused-ultrasound procedures such as vessel cauterization or clot lysis, targeting accuracy is critical. To investigate the targeting accuracy of the focused-ultrasound systems, tissue phantoms embedded with thermocouples can be employed. This paper describes a method that utilizes an array of thermocouples to localize the focused ultrasound beam. All of the thermocouples are located away from the beam, so that thermocouple artifacts and sensor interference are minimized. Beam propagation and temperature rise in the phantom are simulated numerically, and an optimization routine calculates the beam location that produces the best agreement between the numerical temperature values and those measured with thermocouples. The accuracy of the method was examined as a function of the array characteristics, including the number of thermocouples in the array and their orientation. For exposures with a 3.3-MHz source, the remote-thermocouple technique was able to predict the focal position to within 0.06 mm. Once the focal location is determined using the localization method, temperatures at desired locations (including the focus) can be estimated from remote thermocouple measurements by curve fitting an analytical solution to the heat equation. Temperature increases in the focal plane were predicted to within 5% agreement with measured values using this method.

  13. New Technology for Remote Testing of Response Time of Installed Thermocouples. Volume 2 - Research Data

    Science.gov (United States)

    1992-01-01

    specific need for a thermocouple with known rapid response time. Glawe and Holanda ~ have reported an extensive study to determine thermocouple time...Continuous Flow Crvo.qenic Tunnel," NASA Technical Memorandum 81825, May 1980. Glawe, G. E., Holanda , R., Krause, L. N., "Recovery and Radiation Corrections

  14. Theoretical and Experimental Research of Error of Method of Thermocouple with Controlled Profile of Temperature Field

    Science.gov (United States)

    Jun, Su; Kochan, O.; Chunzhi, Wang; Kochan, R.

    2015-12-01

    The method of study and experimental researches of the error of method of the thermocouple with controlled profile of temperature field along the main thermocouple are considered in this paper. Experimentally determined values of error of method are compared to the theoretical estimations done using Newton's law of cooling. They converge well.

  15. Theoretical and Experimental Research of Error of Method of Thermocouple with Controlled Profile of Temperature Field

    OpenAIRE

    Jun Su; Kochan O.; Chunzhi Wang; Kochan R.

    2015-01-01

    The method of study and experimental researches of the error of method of the thermocouple with controlled profile of temperature field along the main thermocouple are considered in this paper. Experimentally determined values of error of method are compared to the theoretical estimations done using Newton’s law of cooling. They converge well.

  16. 77 FR 30435 - In-core Thermocouples at Different Elevations and Radial Positions in Reactor Core

    Science.gov (United States)

    2012-05-23

    ... COMMISSION 10 CFR Part 50 In-core Thermocouples at Different Elevations and Radial Positions in Reactor Core... ``require all holders of operating licenses for nuclear power plants (``NPP'') to operate NPPs with in-core thermocouples at different elevations and radial positions throughout the reactor core.'' DATES: Submit...

  17. High-Temperature, Thin-Film Ceramic Thermocouples Developed

    Science.gov (United States)

    Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2005-01-01

    To enable long-duration, more distant human and robotic missions for the Vision for Space Exploration, as well as safer, lighter, quieter, and more fuel efficient vehicles for aeronautics and space transportation, NASA is developing instrumentation and material technologies. The high-temperature capabilities of thin-film ceramic thermocouples are being explored at the NASA Glenn Research Center by the Sensors and Electronics Branch and the Ceramics Branch in partnership with Case Western Reserve University (CWRU). Glenn s Sensors and Electronics Branch is developing thin-film sensors for surface measurement of strain, temperature, heat flux, and surface flow in propulsion system research. Glenn s Ceramics Branch, in conjunction with CWRU, is developing structural and functional ceramic technology for aeropropulsion and space propulsion.

  18. Lifetime improvement of sheathed thermocouples for use in high-temperature and thermal operations

    Science.gov (United States)

    McCulloch, R. W.; Clift, J. H.

    Premature failure of small-diameter, magnesium-oxide-insulated sheathed thermocouples occurred when they were placed within nuclear fuel rod simulators to measure high temperatures and to follow severe thermal transients encountered during simulation of nuclear accidents in Oak Ridge National Laboratory thermal-hydraulic test facilities. Investigation of thermally cycled thermocouples yielded three criteria for improvement of thermocouple lifetime: (1) reduction of oxygen impurities prior to and during their fabrication; (2) refinement of thermoelement grain size during their fabrication; and (3) elimination of prestrain prior to use above their recrystallization temperature. The first and third criteria were satisfied by improved techniques of thermocouple assembly and by a recovery anneal prior to thermocouple use.

  19. Ion exchange equilibria in simultaneous extraction of platinum(II, IV) and rhodium(III) from hydrochloric solutions

    Science.gov (United States)

    Mel'nikov, A. M.; Kononova, O. N.; Pavlenko, N. I.; Krylov, A. S.

    2012-06-01

    Regularities of sorption extraction of platinum(II, IV) and rhodium(III) by anion exchangers of various physical and chemical structure in the presence of hydrochloric media were studied. It is established that AM-2B, Purolite A 500, and Purolite S 985 ionites adsorb complex anions of platinum metals employing mixed mechanism. A high affinity of the studied anionites for the studied complex anions of platinum and rhodium is established.

  20. Multi-elemental characterization of tunnel and road dusts in Houston, Texas using dynamic reaction cell-quadrupole-inductively coupled plasma-mass spectrometry: Evidence for the release of platinum group and anthropogenic metals from motor vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Spada, Nicholas; Bozlaker, Ayse [Department of Civil and Environmental Engineering, University of Houston, Houston, TX 77204-4003 (United States); Chellam, Shankararaman, E-mail: chellam@uh.edu [Department of Civil and Environmental Engineering, University of Houston, Houston, TX 77204-4003 (United States); Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204-4004 (United States)

    2012-07-20

    Highlights: Black-Right-Pointing-Pointer Analytical method for PGEs, main group, transition and rare earth metals developed. Black-Right-Pointing-Pointer Comprehensive characterization of road and tunnel dust samples was accomplished. Black-Right-Pointing-Pointer PGEs in dusts arise from autocatalyst attrition. Black-Right-Pointing-Pointer Mobile sources also contributed to Cu, Zn, Ga, As, Mo, Cd, Sn, Sb, Ba, W and Pb. Black-Right-Pointing-Pointer All other elements, including rare earths arose from crustal sources. - Abstract: Platinum group elements (PGEs) including Rh, Pd, and Pt are important tracers for vehicular emissions, though their measurement is often challenging and difficult to replicate in environmental campaigns. These challenges arise from sample preparation steps required for PGE quantitation, which often cause severe isobaric interferences and spectral overlaps from polyatomic species of other anthropogenically emitted metals. Consequently, most previous road dust studies have either only quantified PGEs or included a small number of anthropogenic elements. Therefore a novel analytical method was developed to simultaneously measure PGEs, lanthanoids, transition and main group elements to comprehensively characterize the elemental composition of urban road and tunnel dusts. Dust samples collected from the vicinity of high-traffic roadways and a busy underwater tunnel restricted to single-axle (predominantly gasoline-driven) vehicles in Houston, TX were analyzed for 45 metals with the newly developed method using dynamic reaction cell-quadrupole-inductively coupled plasma-mass spectrometry (DRC-q-ICP-MS). Average Rh, Pd and Pt concentrations were 152 {+-} 52, 770 {+-} 208 and 529 {+-} 130 ng g{sup -1} respectively in tunnel dusts while they varied between 6 and 8 ng g{sup -1}, 10 and 88 ng g{sup -1} and 35 and 131 ng g{sup -1} in surface road dusts. Elemental ratios and enrichment factors demonstrated that PGEs in dusts originated from autocatalyst

  1. 阳离子树脂净化铂族金属溶液的研究%Purification of Platinum Group Metals Solution by Cation Exchange

    Institute of Scientific and Technical Information of China (English)

    毕向光; 余建民; 杨金富; 贺洪亮; 李权

    2015-01-01

    研究了阳离子交换树脂净化含大量贱金属的铂族金属溶液的工艺条件,结果表明,在pH=1~1.5时001×7阳离子交换树脂吸附贱金属的次序为:Ni>Cu>Co>Fe;Fe、Ni、Co、Cu的穿透容量分别为(g/kg):0.13,1.25,0.42,0.87;饱和容量分别为(g/kg):0.32,6.65,2.33,4.72,合计为14.02 g/kg;贱金属的分离效率主要取决于贵贱金属浓度及交换柱的数量;吸附在树脂上的贱金属极易被6 mol/L HCl洗脱,所有贱金属的最大洗脱均发生在洗脱液体积与床体积之比为1.0/1.7处,当洗脱液体积为床体积的2.0倍时贱金属被完全洗脱。实验结果为离子交换分离贱金属净化铂族金属溶液的工业化应用提供了强有力的理论依据。%The platimum group metals ( PGMs) solution containing a large amount of base metals purified with cation exchange resin had been investigated. The results showed that the adsorption of base metals by 001 × 7 cation ion exchange resin at pH=1~1.5 was in the order of Ni>Cu>Co>Fe. From the tests, the breakthrough capacities ( g/kg) of Fe, Ni, Co and Cu were 0.13, 1.25, 0.42 and 0.87, respectively, while the saturated capacities ( g/kg) were 0.32, 6.65, 2.33 and 4.72, respectively and 14.02 g/kg in total. It is shown that the separation efficiency of the base metals depends largely on the concentrations of the precious and base metals, as well as the number of exchange columns. The base metals absorbed on the resin could be easily eluted by adding HCl solution at the amount of 6 mol/L, with the elution reaching the maximum as the eluent volume and bed volume at the ratio of 1.0/1.7 and completely finished as the eluent volume being 2. 0 times the bed volume. The experimental results can definitely provide a theoretical basis favorably for the industrial application of PGMs solution purified by cation exchange resin.

  2. Assessment of metallic mineral resources in the Humboldt River Basin, Northern Nevada, with a section on Platinum-Group-Element (PGE) Potential of the Humboldt Mafic Complex

    Science.gov (United States)

    Wallace, Alan R.; Ludington, Steve; Mihalasky, Mark J.; Peters, Stephen G.; Theodore, Ted G.; Ponce, David A.; John, David A.; and Berger, Byron R.; Zientek, Michael L.; Sidder, Gary B.; Zierenberg, Robert A.

    2004-01-01

    The Humboldt River Basin is an arid to semiarid, internally drained basin that covers approximately 43,000 km2 in northern Nevada. The basin contains a wide variety of metallic and nonmetallic mineral deposits and occurrences, and, at various times, the area has been one of the Nation's leading or important producers of gold, silver, copper, mercury, and tungsten. Nevada currently (2003) is the third largest producer of gold in the world and the largest producer of silver in the United States. Current exploration for additional mineral deposits focuses on many areas in northern Nevada, including the Humboldt River Basin.

  3. Platinum and Other Transition Metal Nanoclusters (Pd, Rh) Stabilized by PAMAM Dendrimer as Excellent Heterogeneous Catalysts: Application to the Methylcyclopentane (MCP) Hydrogenative Isomerization.

    Science.gov (United States)

    Deraedt, Christophe; Melaet, Gérôme; Ralston, Walter T; Ye, Rong; Somorjai, Gabor A

    2017-03-08

    Pt, Rh, and Pd nanoclusters stabilized by PAMAM dendrimer are used for the first time in a gas flow reactor at high temperature (150-250 °C). Pt nanoclusters show a very high activity for the hydrogenation of the methylcyclopentane (MCP) at 200-225 °C with turnover freqency (TOF) up to 334 h(-1) and selectivity up to 99.6% for the ring opening isomerization at very high conversion (94%). Rh nanoclusters show different selectivity for the reaction, that is, ring opening isomerization at 175 °C and cracking at higher temperature whereas Pd nanoclusters perform ring enlargement plus dehydrogenation, while maintaining a high activity. The difference in these results as compared to unsupported/uncapped nanoparticles, demonstrates the crucial role of dendrimer. The tunability of the selectivity of the reaction as well as the very high activity of the metal nanoclusters stabilized by dendrimer under heterogeneous conditions open a new application for dendrimer catalysts.

  4. Clinical pharmacology and pharmacokinetics of cis-platinum and analogs.

    Science.gov (United States)

    Ribaud, P; Gouveia, J; Bonnay, M; Mathe, G

    1981-01-01

    cis-Platinum (DDP), the first metal coordination complex introduced into clinical trials, is remarkable for its therapeutic index. A short review of the numerator of this index, ie, the clinical activities of DDP given as a single agent or in combination therapy is presented. Toxicity of DDP, the denominator of the index, is given more attention, particularly nephrotoxicity, whose cumulative character and molecular mechanism are still in question and which can most often be prevented by following certain safety rules that are detailed in this paper. Pharmacokinetics data of free and filterable platinum are reviewed and discussed according to the different modalities of administration of DDP, and to what is known about its toxicity and its mechanism of cell kill. The rationale for using DDP in combination treatment is presented and the question of possible long-term toxicities is raised. cis-platinum analogs are sought for the purpose of enlarging the spectrum of activity, increasing selectivity and diminishing toxicity. Malonato-platinum has been shown not to be cross-resistant with DDP and to be clinically effective in adult acute leukemia. In a phase I study, malonato-platinum, which is poorly soluble, was administered in 6-24-hour infusions to 49 patients in doses ranging from 3 to 32 mg/kg. GI toxicity was universal. Hematological toxicity appeared to be mild and not clearly dose-related (the 3-32 mg/kg patients were not yet evaluable). Platinum pharmacokinetics in urine and plasma were performed using flameless absorption spectrophotometry. Preliminary results have suggested that malonato-platinum presented several pharmacokinetic features in common with DDP. Minor responses were seen in four solid tumor patients, three of whom were refractory to DDP. Other analogs soon to be introduced into clinical trials are listed.

  5. 铠装热电偶两种校准方法的比较%The comparison of two calibration methods of Sheathed thermocouple

    Institute of Scientific and Technical Information of China (English)

    朱欣贇; 郑伟; 龚宝妹; 张雪峰

    2014-01-01

    通过JJG 351-1996与JJF 1262-2010两种方法对8支铠装K型热电偶进行测试,分析得出后者方法的复现性更佳,不确定度更小,更符合铠装廉金属热电偶的固有特性。%In this article, we calibrate 8 K type Sheathed thermocouples according to JJG 351-1996“Verification Regulation of Working Base Metal Thermocouple”and JJF 1262-2010“Calibration Spectification for Sheathed Thermocouples”. The research results indicate that the latter method gets better Reproducibility and smaller Uncertainty. So the latter method is better for the calibration of sheathed thermocouple.

  6. Platinum-Iridium Alloy Films Prepared by MOCVD

    Institute of Scientific and Technical Information of China (English)

    WEI Yan; CHEN Li; CAI Hongzhong; ZHENG Xu; YANG Xiya; HU Changyi

    2012-01-01

    Platinum-Iridium alloy films were prepared by MOCVD on Mo substrate using metal-acetylacetonate precursors.Effects of deposition conditions on composition,microstructure and mechanical properties were determined.In these experimental conditions,the purities of films are high and more than 99.0%.The films are homogeneous and monophase solid solution of Pt and Ir.Weight percentage of platinum are much higher than iridium in the alloy.Lattice constant of the alloy changes with the platinum composition.Iridium composition showing an up-down-up trend at the precursor temperature of 190~230℃ and the deposition temperature at 400~550℃.The hardness of Pt-Ir alloys prepared by MOCVD is three times more than the alloys prepared by casting.

  7. Use of thermocouples in the intense fields of ferromagnetic implant hyperthermia.

    Science.gov (United States)

    Chan, K W; Chou, C K

    1993-01-01

    Thermocouples have been used in the intense fields of ferromagnetic implant hyperthermia for extensive temperature measurements. Electromagnetic interference at 100 kHz is minimized with feed-through filters mounted on a copper plate in a shielded assembly. The thermocouples are temperature compensated in the software by monitoring the temperature of the copper plate. D-shell connectors are used for multiple sensor thermocouple connections and to provide proper shield termination of external cables. The technical approaches of grounding, shielding and filtering are examined, and experiments have been conducted to determine the proper usage of thermocouple during ferromagnetic implant treatments. The dependence of filter performance on thermocouple impedance and the effect of D-shell connections on temperature accuracy have been studied. The results indicate that self-heating due to electromagnetic energy coupled into 51 microns thermocouple leads and unbalanced current along 76 microns leads are insignificant at 100 kHz. But severe heating has been observed in 511 and 813 microns leads, especially in high-conductivity copper wires. By using 25-50 microns thermocouple leads, better than 0.1 degree C accuracy and 0.05 degree C resolution have been achieved during ferromagnetic hyperthermia. At field strength of 1500 A/m, artifacts of 0.03-0.05 degree C are observed.

  8. Temperature artifacts produced by thermocouples used in conjunction with 1 and 3 MHz ultrasound.

    Science.gov (United States)

    Waterman, F M; Leeper, J B

    1990-01-01

    The relative temperature artifacts produced by a selection of commercially available thermocouples and catheters were evaluated in radiation bolus and beef phantoms heated by 1 and 3 MHz continuous ultrasound. The thermocouples included a 23 gauge needle microprobe inserted directly into the phantoms, polyurethane-sheathed, Teflon-sheathed, and exposed-tip thermocouples, each inserted into a 19 gauge polyurethane closed-end catheter, a multisensor Teflon-sheathed probe inserted into a 16 gauge polyurethane catheter and a Teflon-sheathed single-sensor probe without a catheter. The needle microprobe and the polyurethane-sheathed thermocouple produce equivalent artifacts. The artifacts produced by the Teflon and exposed-tip thermocouples are 1.4 +/- 0.3 times greater, that produced by the multisensor Teflon-sheathed probe is 2.1 +/- 0.3 times greater, and that produced by the Teflon-sheathed thermocouple without a catheter is 2.3 +/- 0.4 times greater. The results in the beef phantom indicate that the needle microprobe and polyurethane-sheathed thermocouple both produce artifacts of 0.7 +/- 0.1 degree in tissue at an SAR of 100 W/kg.

  9. Contact Thermocouple Methodology and Evaluation for Temperature Measurement in the Laboratory

    Science.gov (United States)

    Brewer, Ethan J.; Pawlik, Ralph J.; Krause, David L.

    2013-01-01

    Laboratory testing of advanced aerospace components very often requires highly accurate temperature measurement and control devices, as well as methods to precisely analyze and predict the performance of such components. Analysis of test articles depends on accurate measurements of temperature across the specimen. Where possible, this task is accomplished using many thermocouples welded directly to the test specimen, which can produce results with great precision. However, it is known that thermocouple spot welds can initiate deleterious cracks in some materials, prohibiting the use of welded thermocouples. Such is the case for the nickel-based superalloy MarM-247, which is used in the high temperature, high pressure heater heads for the Advanced Stirling Converter component of the Advanced Stirling Radioisotope Generator space power system. To overcome this limitation, a method was developed that uses small diameter contact thermocouples to measure the temperature of heater head test articles with the same level of accuracy as welded thermocouples. This paper includes a brief introduction and a background describing the circumstances that compelled the development of the contact thermocouple measurement method. Next, the paper describes studies performed on contact thermocouple readings to determine the accuracy of results. It continues on to describe in detail the developed measurement method and the evaluation of results produced. A further study that evaluates the performance of different measurement output devices is also described. Finally, a brief conclusion and summary of results is provided.

  10. Temporary Thermocouple Attachment for Thermal/Vacuum Testing at Non-Extreme Temperatures - Test Results

    Science.gov (United States)

    Wright, Sarah E.; Ungar, Eugene K.

    2017-01-01

    Post-test examination and data analysis that followed a two week long vacuum test showed that numerous self-stick thermocouples became detached from the test article. The thermocouples were reattached with thermally conductive epoxy and the test was repeated to obtain the required data. Because the thermocouple detachment resulted in significant expense and rework, it was decided to investigate the temporary attachment methods used around NASA and to perform a test to assess their efficacy. The present work describes the testing that was performed in early and mid-2017. The test article and the temporary thermocouple attachment methods tested are described. During the first test, fully half of the thermocouples detached - although the detachment showed subtly in the data for some. The second test was performed to confirm the data from the first test and to investigate the effect of test article and thermocouple grounding. The results of the testing over temperatures ranging from -150 to 200degF are detailed and preliminary recommendations are made for temporary thermocouple attachment methods.

  11. Development of Platinum(iv) Complexes as Anticancer Prodrugs: the Story so Far

    Science.gov (United States)

    Wong, Daniel Yuan Qiang; Ang, Wee Han

    2012-06-01

    The serendipitous discovery of the antitumor properties of cisplatin by Barnett Rosenberg some forty years ago brought about a paradigm shift in the field of medicinal chemistry and challenged conventional thinking regarding the role of potentially toxic heavy metals in drugs. Platinum(II)-based anticancer drugs have since become some of the most effective and widely-used drugs in a clinician's arsenal and have saved countless lives. However, they are limited by high toxicity, severe side-effects and the incidence of drug resistance. In recent years, attention has shifted to stable platinum(IV) complexes as anticancer prodrugs. By exploiting the unique chemical and structural attributes of their scaffolds, these platinum(IV) prodrugs offer new strategies of targeting and killing cancer cells. This review summarizes the development of anticancer platinum(IV) prodrugs to date and some of the exciting strategies that utilise the platinum(IV) construct as targeted chemotherapeutic agents against cancer.

  12. Platinum-Free Counter Electrode Comprised of Metal-Organic-Framework (MOF)-Derived Cobalt Sulfide Nanoparticles for Efficient Dye-Sensitized Solar Cells (DSSCs)

    Science.gov (United States)

    Hsu, Shao-Hui; Li, Chun-Ting; Chien, Heng-Ta; Salunkhe, Rahul R.; Suzuki, Norihiro; Yamauchi, Yusuke; Ho, Kuo-Chuan; Wu, Kevin C.-W.

    2014-11-01

    We fabricated a highly efficient (with a solar-to-electricity conversion efficiency (η) of 8.1%) Pt-free dye-sensitized solar cell (DSSC). The counter electrode was made of cobalt sulfide (CoS) nanoparticles synthesized via surfactant-assisted preparation of a metal organic framework, ZIF-67, with controllable particle sizes (50 to 320 nm) and subsequent oxidation and sulfide conversion. In contrast to conventional Pt counter electrodes, the synthesized CoS nanoparticles exhibited higher external surface areas and roughness factors, as evidenced by X-ray diffraction (XRD), scanning electron microscopy (SEM) element mapping, and electrochemical analysis. Incident photon-to-current conversion efficiency (IPCE) results showed an increase in the open circuit voltage (VOC) and a decrease in the short-circuit photocurrent density (Jsc) for CoS-based DSSCs compared to Pt-based DSSCs, resulting in a similar power conversion efficiency. The CoS-based DSSC fabricated in the study show great potential for economically friendly production of Pt-free DSSCs.

  13. Synthesis and structural study of platinum group metal complexes containing pyrimidine bridged pyrazolyl-pyridine ligand and 5 and 6 - cyclic hydrocarbons

    Indian Academy of Sciences (India)

    Thirumala Prasad Kota; Mohan Rao Kollipara

    2014-07-01

    The mononuclear compounds [(6-arene)Ru(bppm)Cl]PF6{bppm = 4,6-bis3-(2-pyridyl)-1Hpyrazol-1-yl}pyrimidine; arene = C6H6, [1]; -$^i$PrC6H4Me, [2]; C6Me6, [3]}, [CpRu(bppm)(PPh3)]PF6{Cp = 5-C5H5, [4]; 5-C5Me5, [5]; 5-C9H7, [6]} and [Cp∗M(bppm)Cl]PF6 {M = Rh [7]; Ir [8]} have been synthesized from the reaction of 4,6-bis{3-(2-pyridyl)-1H-pyrazol-1-yl}pyrimidine (bppm) and the corresponding precursor metal complexes [(6-arene)Ru(-Cl)Cl]2, [CpRu(PPh3)2Cl] and [Cp∗M(-Cl)Cl]2, respectively, in the presence of NH4PF6. They were characterized by the following techniques viz. IR, NMR, mass spectrometry and UV-visible spectroscopy. The molecular structures of [2] and [7] have been established by single crystal X-ray structure analyses.

  14. Vapour Treatment Method Against Other Pyro- and Hydrometallurgical Processes Applied to Recover Platinum From Used Auto Catalytic Converters

    Institute of Scientific and Technical Information of China (English)

    Agnieszka FORNALCZYK; Mariola SATERNUS

    2013-01-01

    Today more and more cars are produced every year.All of them have to be equipped with catalytic converters,the main role of which is to obtain substances harmless to the environment instead of exhausted gases.Catalytic converters contain platinum group metals (PGM) especially platinum,palladium and rhodium.The price of these metals and their increasing demand are the reasons why today it is necessary to recycle used auto catalytic converters.There are many available methods of recovering PGM metals from them,especially platinum.These methods used mainly hydrometallurgical processes; however pyrometallurgical ones become more and more popular.The article presents results of the research mainly concerning pyrometallurgical processes.Two groups of research were carried out.In the first one different metals such as lead,magnesium and copper were used as a metal collector.During the tests,platinum went to those metals forming an alloy.In other research metal vapours were blown through catalytic converter carrier (grinded or whole).In the tests metals such as calcium,magnesium,cadmium and zinc were applied.As a result white or grey powder (metal plus platinum) was obtained.The tables present results of the research.Processing parameters and conclusions are also shown.To compare efficiency of pyrometallurgical and hydrometallurgical methods catalytic converter carrier and samples of copper with platinum obtained from pyrometallurgical method were solved in aqua regia,mixture of aqua regia and fluoric acid.

  15. Effects of thermocouple electrical insulation on the measurement of surface temperature

    OpenAIRE

    AlWaaly, Ahmed A.Y.; Paul, Manosh C; Dobson, Phillip S.

    2015-01-01

    Analytical, numerical and experimental analyses have been performed to investigate the effects of thermocouple wire electrical insulation on the temperature measurement of a reference surface. Two diameters of type K thermocouple, 80 μm and 200 μm, with different exposed wire lengths (0 mm, 5 mm, 10 mm, 15 mm and 20 mm) were used to measure various surface temperatures (4 °C, 8 °C, 15 °C, 25 °C and 35 °C). Measurements were made with the thermocouple in direct contact with the surface, with w...

  16. Studies of Behavior Melting Temperature Characteristics for Multi Thermocouple In-Core Instrument Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Donghyup; Chae, Myoungeun; Kim, Sungjin; Lee, Kyulim [Woojin inc, Hwasung (Korea, Republic of)

    2015-05-15

    Bottom-up type in-core instruments (ICIs) are used for the pressurized water reactors of OPR-1000, APR- 1400 in order to measure neutron flux and temperature in the reactor. It is a well-known technique and a proven design using years in the nuclear field. ICI consists of one pair of K-type thermocouple, five self-powered neutron detectors (SPNDs) and one back ground detector. K-type thermocouple's purpose is to measure the core exit temperature (CET) in the reactor. The CET is a very important factor for operating nuclear power plants and it is 327 .deg. C when generally operating the reactor in the nuclear power plant(NPP) in case of OPR- 1000. If the CET will exceed 650 .deg. C, Operators in the main control room should be considered to be an accident situation in accordance with a severe accident management guidance(SAMG). The Multi Thermocouple ICI is a new designed ICI assuming severe accident conditions. It consists of four more thermocouples than the existing design, so it has five Ktype thermocouples besides the thermocouple measuring CET is located in the same elevation as the ICI. Each thermocouple is able to be located in the desired location as required. The Multi Thermocouple ICI helps to measure the temperature distribution of the entire reactor. In addition, it will measure certain point of melted core because of the in-vessel debris of nuclear fuel when an accident occurs more seriously. In this paper, to simulate a circumstance such as a nuclear reactor severe accident was examined. In this study, the K-type thermocouples of Multi Thermocouple ICI was confirmed experimentally to be able to measure up to 1370 .deg. C before the thermocouples have been melted. And after the thermocouples were melted by debris, it was able to be monitored that the signal of EMF directed the infinite value of voltage. Therefore through the results of the test, it can be assumed that if any EMF data among the Multi Thermocouple ICI will direct the infinite value

  17. Calibration of thermocouple psychrometers and moisture measurements in porous materials

    Science.gov (United States)

    Guz, Łukasz; Sobczuk, Henryk; Połednik, Bernard; Guz, Ewa

    2016-07-01

    The paper presents in situ method of peltier psychrometric sensors calibration which allow to determine water potential. Water potential can be easily recalculated into moisture content of the porous material. In order to obtain correct results of water potential, each probe should be calibrated. NaCl salt solutions with molar concentration of 0.4M, 0.7M, 1.0M and 1.4M, were used for calibration which enabled to obtain osmotic potential in range: -1791 kPa to -6487 kPa. Traditionally, the value of voltage generated on thermocouples during wet-bulb temperature depression is calculated in order to determine the calibration function for psychrometric in situ sensors. In the new method of calibration, the field under psychrometric curve along with peltier cooling current and duration was taken into consideration. During calibration, different cooling currents were applied for each salt solution, i.e. 3, 5, 8 mA respectively, as well as different cooling duration for each current (from 2 to 100 sec with 2 sec step). Afterwards, the shape of each psychrometric curve was thoroughly examined and a value of field under psychrometric curve was computed. Results of experiment indicate that there is a robust correlation between field under psychrometric curve and water potential. Calibrations formulas were designated on the basis of these features.

  18. Comparative analysis of high temperature strength of platinum and its binary alloys with low content of alloying element

    Directory of Open Access Journals (Sweden)

    Stanković Draško S.

    2012-01-01

    Full Text Available The comparative analysis of platinum and its binary alloys (containing alloying elements up to 10 mass% mechanical properties at high temperatures has been carried out. The goal of the analysis was to investigate new application possibilities for products based on platinum and platinum alloys, and to expand the existing database of platinum metals, originating from the RTB group, Serbia. Palladium, rhodium, ruthenium, iridium and gold were used as alloying elements. In order to examine the effect of alloying elements’ low concentrations on the high-temperature platinum durability, creep rate, rupture time, tensile strength and relative elongation at high temperatures, up to 1400 °C, were determined. In addition, changes in the structure of dislocations were tracked. The summary of investigation results led to conclusion that, of all the alloying elements used, the best influence on high-temperature platinum durability has rhodium.

  19. Porous platinum-based catalysts for oxygen reduction

    Science.gov (United States)

    Erlebacher, Jonah D; Snyder, Joshua D

    2014-11-25

    A porous metal that comprises platinum and has a specific surface area that is greater than 5 m.sup.2/g and less than 75 m.sup.2/g. A fuel cell includes a first electrode, a second electrode spaced apart from the first electrode, and an electrolyte arranged between the first and the second electrodes. At least one of the first and second electrodes is coated with a porous metal catalyst for oxygen reduction, and the porous metal catalyst comprises platinum and has a specific surface area that is greater than 5 m.sup.2/g and less than 75 m.sup.2/g. A method of producing a porous metal according to an embodiment of the current invention includes producing an alloy consisting essentially of platinum and nickel according to the formula Pt.sub.xNi.sub.1-x, where x is at least 0.01 and less than 0.3; and dealloying the alloy in a substantially pH neutral solution to reduce an amount of nickel in the alloy to produce the porous metal.

  20. Highly trifluoromethylated platinum compounds.

    Science.gov (United States)

    Martínez-Salvador, Sonia; Forniés, Juan; Martín, Antonio; Menjón, Babil

    2011-07-11

    The homoleptic, square-planar organoplatinum(II) compound [NBu(4)](2) [Pt(CF(3))(4)] (1) undergoes oxidative addition of CF(3) I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu(4)](2) [Pt(CF(3))(5)I] (2). This highly trifluoromethylated species reacts with Ag(+) salts of weakly coordinating anions in Me(2)CO under a wet-air stream to afford the aquo derivative [NBu(4)][Pt(CF(3))(5) (OH(2))] (4) in around 75% yield. When the reaction of 2 with the same Ag(+) salts is carried out in MeCN, the solvento compound [NBu(4) ][Pt(CF(3))(5)(NCMe)] (5) is obtained in around 80% yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu(4)][Pt(CF(3))(5) (L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu(4)](2) [Pt(CF(3))(5)X] (X=Cl (9), Br (10)). The unusual carbonyl-platinum(IV) derivative [NBu(4)][Pt(CF(3))(5) (CO)] (6) is thermally stable and has a ν(CO) of 2194 cm(-1). The crystal structures of 2⋅CH(2)Cl(2), 5, [PPh(4) ][Pt(CF(3))(5)(CO)] (6'), and 7 have been established by X-ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4-10 are the organoelement compounds with the highest CF(3) content to have been isolated and adequately characterized to date.

  1. Understanding platinum-induced ototoxicity.

    Science.gov (United States)

    Langer, Thorsten; am Zehnhoff-Dinnesen, Antoinette; Radtke, Susanne; Meitert, Johannes; Zolk, Oliver

    2013-08-01

    Childhood cancer survival rates are now nearly 80% in more developed European countries because of improved therapies and better supportive care. Platinum chemotherapy drugs, such as cisplatin and carboplatin, are the cornerstone of many effective therapeutic protocols for childhood cancer. However, the antitumor efficacy of cisplatin and carboplatin comes at the cost of ototoxicity, which affects at least 60% of pediatric patients. Although ototoxicity is not life threatening, it can have debilitating effects on patients' quality of life. Recently, many initiatives have been launched with the ultimate goal of reducing cisplatin and high-dose carboplatin ototoxicity without compromising antitumor efficacy. This review addresses the incidence of platinum ototoxicity and its clinical presentation, time course, and early diagnostic evaluation. Genetic and non-genetic risk factors for platinum-associated ototoxicity, and their predictive value, are discussed. Recent developments in the prevention of platinum ototoxicity are also summarized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Comparison between Base Metals and Platinum Group Metals in Nitrogen, M Codoped TiO2 (M = Fe, Cu, Pd, Os for Photocatalytic Removal of an Organic Dye in Water

    Directory of Open Access Journals (Sweden)

    Alex T. Kuvarega

    2014-01-01

    Full Text Available The photocatalytic performance of a number of nonmetal and metal codoped TiO2 for the degradation of eosin yellow under simulated solar radiation was investigated. The synthesised materials were characterised by FTIR, Raman spectroscopy, XRD, DRUV-Vis, SEM, and TEM. The N, metal codoped TiO2 containing 0.5 wt.% of the metal consisted mainly of the anatase phase, with a particle size range of 15–28 nm. The particles were largely spherical and shifted the absorption edge well into the visible region. Band gap reduction was more pronounced for the N, PGM codoped TiO2 compared to N, base metal codoped samples. Codoping led to an enhancement in the photocatalytic activity of the materials for the degradation of eosin yellow. N, Pd codoped TiO2 was the most effective photocatalyst (99.9% dye removal while N, Cu codoped TiO2 showed the least activity (25.5% removal. The mechanism for the photocatalytic enhancement was proposed on the basis of formation of an electron deficient Schottky barrier at the semiconductor-metal interface, which acts as an electron sink and thus retards electron-hole recombination. It was shown that the ability of the photocatalyst to degrade the dye depends on the nature and type of the metal dopant in the codoped TiO2 system.

  3. Evaluation of miniature single-wire sheathed thermocouples for turbine blade temperature measurement

    Science.gov (United States)

    Hollanda, R.

    1979-01-01

    Chromel Alumel thermocouples were used, with sheath diameters of 0.15 and 0.25 mm. Tests were conducted at temperatures ranging from 750 to 1250 K. Both steady state and thermal cycling tests were performed for times up to 200 hours. Initial testing was performed in a low velocity gas stream for long time periods using a Meker-type burner. Additional testing was done in a high velocity gas stream for short time periods using a hot gas tunnel and also in a J75 jet engine. A total of eleven 0.15 mm diameter thermocouples and six 0.25 mm diameter thermocouples were tested. Drift rates up to 2.5% in 10 hours were observed. Photomicrographs show that this design is near the limit of miniaturization based on present manufacturing capabilities. Results indicate that the effects of miniaturization on reliability and accuracy must be considered when choosing thermocouples for a particular application.

  4. Polyamide platinum anticancer complexes designed to target specific DNA sequences.

    Science.gov (United States)

    Jaramillo, David; Wheate, Nial J; Ralph, Stephen F; Howard, Warren A; Tor, Yitzhak; Aldrich-Wright, Janice R

    2006-07-24

    Two new platinum complexes, trans-chlorodiammine[N-(2-aminoethyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-2) and trans-chlorodiammine[N-(6-aminohexyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-6) have been synthesized as proof-of-concept molecules in the design of agents that can specifically target genes in DNA. Coordinate covalent binding to DNA was demonstrated with electrospray ionization mass spectrometry. Using circular dichroism, these complexes were found to show greater DNA binding affinity to the target sequence: d(CATTGTCAGAC)(2), than toward either d(GTCTGTCAATG)(2,) which contains different flanking sequences, or d(CATTGAGAGAC)(2), which contains a double base pair mismatch sequence. DJ1953-2 unwinds the DNA helix by around 13 degrees , but neither metal complex significantly affects the DNA melting temperature. Unlike simple DNA minor groove binders, DJ1953-2 is able to inhibit, in vitro, RNA synthesis. The cytotoxicity of both metal complexes in the L1210 murine leukaemia cell line was also determined, with DJ1953-6 (34 microM) more active than DJ1953-2 (>50 microM). These results demonstrate the potential of polyamide platinum complexes and provide the structural basis for designer agents that are able to recognize biologically relevant sequences and prevent DNA transcription and replication.

  5. Platinum availability for future automotive technologies.

    Science.gov (United States)

    Alonso, Elisa; Field, Frank R; Kirchain, Randolph E

    2012-12-04

    Platinum is an excellent catalyst, can be used at high temperatures, and is stable in many aggressive chemical environments. Consequently, platinum is used in many current industrial applications, notably automotive catalytic converters, and prospective vehicle fuel cells are expected to rely upon it. Between 2005 and 2010, the automotive industry used approximately 40% of mined platinum. Future automotive industry growth and automotive sales shifts toward new technologies could significantly alter platinum demand. The potential risks for decreased platinum availability are evaluated, using an analysis of platinum market characteristics that describes platinum's geophysical constraints, institutional efficiency, and dynamic responsiveness. Results show that platinum demand for an automotive fleet that meets 450 ppm greenhouse gas stabilization goals would require within 10% of historical growth rates of platinum supply before 2025. However, such a fleet, due largely to sales growth in fuel cell vehicles, will more strongly constrain platinum supply in the 2050 time period. While current platinum reserves are sufficient to satisfy this increased demand, decreasing platinum ore grade and continued concentration of platinum supply in a single geographic area are availability risk factors to platinum end-users.

  6. The Next Generation of Platinum Drugs: Targeted Pt(II) Agents, Nanoparticle Delivery, and Pt(IV) Prodrugs.

    Science.gov (United States)

    Johnstone, Timothy C; Suntharalingam, Kogularamanan; Lippard, Stephen J

    2016-03-09

    The platinum drugs, cisplatin, carboplatin, and oxaliplatin, prevail in the treatment of cancer, but new platinum agents have been very slow to enter the clinic. Recently, however, there has been a surge of activity, based on a great deal of mechanistic information, aimed at developing nonclassical platinum complexes that operate via mechanisms of action distinct from those of the approved drugs. The use of nanodelivery devices has also grown, and many different strategies have been explored to incorporate platinum warheads into nanomedicine constructs. In this Review, we discuss these efforts to create the next generation of platinum anticancer drugs. The introduction provides the reader with a brief overview of the use, development, and mechanism of action of the approved platinum drugs to provide the context in which more recent research has flourished. We then describe approaches that explore nonclassical platinum(II) complexes with trans geometry or with a monofunctional coordination mode, polynuclear platinum(II) compounds, platinum(IV) prodrugs, dual-threat agents, and photoactivatable platinum(IV) complexes. Nanoparticles designed to deliver platinum(IV) complexes will also be discussed, including carbon nanotubes, carbon nanoparticles, gold nanoparticles, quantum dots, upconversion nanoparticles, and polymeric micelles. Additional nanoformulations, including supramolecular self-assembled structures, proteins, peptides, metal-organic frameworks, and coordination polymers, will then be described. Finally, the significant clinical progress made by nanoparticle formulations of platinum(II) agents will be reviewed. We anticipate that such a synthesis of disparate research efforts will not only help to generate new drug development ideas and strategies, but also will reflect our optimism that the next generation of approved platinum cancer drugs is about to arrive.

  7. Chemical composition of the ore and occurrence state of the elements in Jingbaoshan platinum- palladium deposit

    Institute of Scientific and Technical Information of China (English)

    SONG Huanbin; HE Mingqin; ZHANG Shangzhong; YI Fenghuang

    2008-01-01

    The Jingbaoshan platinum-palladium deposit is China's largest independent PGM (platinum-group metals) deposit so far discovered. There are eleven kinds of useful components in the ore: Pt, Pd, Os, Ir, Ru, Rh, Au, Ag, Cu, Ni, and Co. The platinum-group elements, gold and silver occur in the form of minerals in ores. twenty-five kinds of precious metal minerals have been found, of which twenty one belong to the platinum-group minerals. The minerals are very small in grain size. Copper occurs mainly as copper sulfide with a small amount of free copper oxide, and the beneficiated copper accounts for 95.21%. Nickel occurs mainly as nickel sulfide, and some nickel silicate and nickel oxide occur in the ore. The beneficiated nickel accounts for 72.03%. Cobalt occurs mainly as cobalt sulfide, and there are some cobalt oxide and other kinds of cobalt. The beneficiated cobalt accounts for 77.58%.

  8. Investigation of mechanical and structural characteristics of platinum and palladium at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Trumie, B. T.; Gomidzelovie, L.; Marjanovic, S. R.; Krstic, V. R.

    2015-03-30

    In order to broaden future application of products based on platinum and palladium a comparative analysis of their high-temperature mechanical properties was performed. Platinum and palladium are of great importance and are widely used in chemical industry, electronics, for making laboratory dishes, to name a few. Mechanical properties of pure metals, such as: tensile strength, creep rate and rupture time were investigated using universal testing machine for tensile testing of materials. Microstructure of samples was investigated by optical microscopy. Based on obtained results it can be concluded that the platinum, compared to palladium, is superior for high-temperature applications. (Author)

  9. High-pressure/high-temperature synthesis and characterization of the first palladium or platinum containing lithium transition-metal sulfides Li2M3S4 (M=Pd, Pt)

    Science.gov (United States)

    Heymann, Gunter; Niehaus, Oliver; Krüger, Hannes; Selter, Philipp; Brunklaus, Gunther; Pöttgen, Rainer

    2016-10-01

    The new lithium transition-metal sulfides Li2M3S4 (M=Pd, Pt) were obtained via multianvil high-pressure/high-temperature syntheses at 8 GPa and 1150 °C starting from a stoichiometric mixture of lithium nitride, sulfur, and palladium or platinum. Single crystal structure analyses indicated the space group P21/c (no. 14) with the following lattice parameters and refinement results: a=492.9(1), b=1005.9(2), c=614.9(2) pm, β=110.9 (1)°, R1=0.0165, wR2=0.0308 (all data) for Li2Pd3S4 and a=498.2(1), b=1005.5(2), c=613.0(2) pm, β=110.8(1)°, R1=0.0215, wR2=0.0450 (all data) for Li2Pt3S4. The crystal structures are built up from two distinct Pd/Pt sites, one of which is a special position (0,0,0), two sulfur sites, and one lithium site. The atoms Pd2/Pt2 form isolated square planar PdS4/PtS4 units, whereas the Pd1/Pt1 atoms form pairs of square planar PdS4/PtS4 units, which are connected via a common edge. These two structural motives built up a three-dimensional network structure by linking through common corners. The lithium atoms are positioned inside of the so formed channels. Li2M3S4 (M=Pd, Pt) are isostructural to the minerals jaguéite, Cu2Pd3Se4 and chrisstanleyite, Ag2Pd3Se4, which are up to now the only representatives of this structure type. Both compounds were studied with respect to their magnetic properties and can be classified as Pauli paramagnetic or diamagnetic. Regarding the possibility of lithium mobility inside the channels, of the structure, solid state 7Li NMR and high-temperature single crystal investigations revealed localization of the lithium atoms on their crystallographic sites.

  10. Surface decorated platinum carbonyl clusters

    Science.gov (United States)

    Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Longoni, Giuliano; Zacchini, Stefano; Zarra, Salvatore

    2012-06-01

    Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters.Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters. CCDC 867747 and 867748. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30400g

  11. Attachment of Free Filament Thermocouples for Temperature Measurements on CMC

    Science.gov (United States)

    Lei, Jih-Fen; Cuy, Michael D.; Wnuk, Stephen P.

    1997-01-01

    Ceramic Matrix Composites (CMC) are being developed for use as enabling materials for advanced aeropropulsion engine and high speed civil transport applications. The characterization and testing of these advanced materials in hostile, high-temperature environments require accurate measurement of the material temperatures. Commonly used wire Thermo-Couples (TC) can not be attached to this ceramic based material via conventional spot-welding techniques. Attachment of wire TC's with commercially available ceramic cements fail to provide sufficient adhesion at high temperatures. While advanced thin film TC technology provides minimally intrusive surface temperature measurement and has good adhesion on the CMC, its fabrication requires sophisticated and expensive facilities and is very time consuming. In addition, the durability of lead wire attachments to both thin film TC's and the substrate materials requires further improvement. This paper presents a newly developed attachment technique for installation of free filament wire TC's with a unique convoluted design on ceramic based materials such as CMC's. Three CMC's (SiC/SiC CMC and alumina/alumina CMC) instrumented with type IC, R or S wire TC's were tested in a Mach 0.3 burner rig. The CMC temperatures measured from these wire TC's were compared to that from the facility pyrometer and thin film TC's. There was no sign of TC delamination even after several hours exposure to 1200 C. The test results proved that this new technique can successfully attach wire TC's on CMC's and provide temperature data in hostile environments. The sensor fabrication process is less expensive and requires very little time compared to that of the thin film TC's. The same installation technique/process can also be applied to attach lead wires for thin film sensor systems.

  12. Study of gold-platinum and platinum-gold surface modification and its influence on hydrogen evolution and oxygen reduction

    Directory of Open Access Journals (Sweden)

    BRANIMIR N. GRGUR

    2005-02-01

    Full Text Available Surface modification of the electrodes was conducted from sulfuric acid solutions containing the corresponding metal–chloride complexes using cyclic voltammetry. Comparing the charges of the hydrogen underpotential deposition region, and the corresponding oxide reduction regions, it is concluded that a platinum overlayer on gold forms 3D islands, while gold on platinum forms 2D islands. Foreign metals present in an amount of up to one monolayer exert an influence on the change in reaction rate with respect to both hydrogen evolution (HER and oxygen reduction (ORR reactions. Aplatinum overlayer on a gold substrate increases the activity forHER and for ORR, compared with pure gold. These results can be understood in terms of a simple model, in which the change in the H and OH binding energies are directly proportional to the shift of the d-bond center of the overlayer. On the contrary, a gold layer on platinum slightly decreases the activity for both reactions compared with pure platinum.

  13. Platinum contamination issues in ferroelectric memories

    Science.gov (United States)

    Boubekeur, H.; Mikolajick, T.; Pamler, W.; Hopfner, J.; Frey, L.; Ryssel, H.

    2002-09-01

    The contamination risk of processing with platinum electrodes on device performance in ferroelectric memories is assessed in this work. Details of platinum diffusion to the active regions at annealing temperatures of 800 degC are investigated by secondary ion mass spectroscopy, deep level transient spectroscopy, and Rutherford backscattering spectrometry techniques. Cross sectional transmission electron microscopy and local elemental analysis by energy dispersive x-ray spectroscopy were used to examine the precipitation of Pt in defect free silicon as an eventual cause of gate oxide degradation. The impact of platinum contamination on device performance is evaluated under the typical ferroelectric memory processing conditions. Results from leakage current and charge to breakdown measurements of intentionally contaminated diode and metal-oxide-semiconductor (MOS) structures, respectively, are presented. The results show that the degradation depends strongly on device design and configuration. A phosphorus doped polysilicon plug, which has the function of connecting the select transistor to the capacitor module, provides effective gettering regions and prevents the diffusion of Pt atoms to the active regions. Under typical processing conditions, no evident Pt precipitates were observed and up to a concentration level of 4 x1014 atoms/cm2, the leakage current of intentionally contaminated diodes does not increase, if the contamination occurs after front-end phosphorus doped poly-Si processing. Results from constant current charge to breakdown show a small number of breakdown events due to redeposition of Pt at the periphery of the MOS structure. The risk of processing with Pt electrodes in ferroelectric memories requires great care. Precautions like sealing the back surface and incorporating phosphorus doped polysilicon as the plug material are necessary to avoid the detrimental effects of Pt.

  14. Electrocatalysts having gold monolayers on platinum nanoparticle cores, and uses thereof

    Science.gov (United States)

    Adzic, Radoslav; Zhang, Junliang

    2010-04-27

    The invention relates to gold-coated particles useful as fuel cell electrocatalysts. The particles are composed of an electrocatalytically active core at least partially encapsulated by an outer shell of gold or gold alloy. The invention more particularly relates to such particles having a noble metal-containing core, and more particularly, a platinum or platinum alloy core. In other embodiments, the invention relates to fuel cells containing these electrocatalysts and methods for generating electrical energy therefrom.

  15. New experimental methodology, setup and LabView program for accurate absolute thermoelectric power and electrical resistivity measurements between 25 and 1600 K: application to pure copper, platinum, tungsten, and nickel at very high temperatures.

    Science.gov (United States)

    Abadlia, L; Gasser, F; Khalouk, K; Mayoufi, M; Gasser, J G

    2014-09-01

    In this paper we describe an experimental setup designed to measure simultaneously and very accurately the resistivity and the absolute thermoelectric power, also called absolute thermopower or absolute Seebeck coefficient, of solid and liquid conductors/semiconductors over a wide range of temperatures (room temperature to 1600 K in present work). A careful analysis of the existing experimental data allowed us to extend the absolute thermoelectric power scale of platinum to the range 0-1800 K with two new polynomial expressions. The experimental device is controlled by a LabView program. A detailed description of the accurate dynamic measurement methodology is given in this paper. We measure the absolute thermoelectric power and the electrical resistivity and deduce with a good accuracy the thermal conductivity using the relations between the three electronic transport coefficients, going beyond the classical Wiedemann-Franz law. We use this experimental setup and methodology to give new very accurate results for pure copper, platinum, and nickel especially at very high temperatures. But resistivity and absolute thermopower measurement can be more than an objective in itself. Resistivity characterizes the bulk of a material while absolute thermoelectric power characterizes the material at the point where the electrical contact is established with a couple of metallic elements (forming a thermocouple). In a forthcoming paper we will show that the measurement of resistivity and absolute thermoelectric power characterizes advantageously the (change of) phase, probably as well as DSC (if not better), since the change of phases can be easily followed during several hours/days at constant temperature.

  16. Nanostructured gold and platinum electrodes on silicon structures for biosensing

    Science.gov (United States)

    Ogurtsov, V. I.; Sheehan, M. M.

    2005-01-01

    Gold and platinum metal electrodes on Si/SiO2 having undergone anisotropic potassium hydroxide (KOH) etch treatment are considered. This treatment etches at different rates and directions in the material resulting in creation of numerous pyramid shaped holes in the silicon substrate. This surface is used to make metal electrodes with increased electrode efficiency. The electrodes can serve as the sensors or as the sensor substrates (for surface polymer modification) and because both gold and platinum are inert they have applications for food safety biosensing. Wine, an economically significant food product, was chosen as a matrix, and impedance spectroscopy (EIS) was selected as a method of investigation of electrode behaviour. Based on results of EIS, different complexity equivalent circuits were determined by applying fitting mean square root optimisation of sensor complex impedance measurements.

  17. Quantitative study of the spin Hall magnetoresistance in ferromagnetic insulator/normal metal hybrids

    NARCIS (Netherlands)

    Althammer, M.; Meyer, S.; Nakayama, H.; Schreier, M.; Altmannshofer, S.; Weiler, M.; Huebl, H.; Gesprägs, S.; Opel, M.; Gross, R.; Meier, D.; Klewe, C.; Kuschel, T.; Schmalhorst, J.M.; Reiss, G.; Shen, L.; Gupta, A.; Chen, Y.T.; Bauer, G.E.W.; Saitoh, E.; Goennenwein, S.T.B.

    2013-01-01

    We experimentally investigate and quantitatively analyze the spin Hall magnetoresistance effect in ferromagnetic insulator/platinum and ferromagnetic insulator/nonferromagnetic metal/platinum hybrid structures. For the ferromagnetic insulator, we use either yttrium iron garnet, nickel ferrite, or ma

  18. Nanostructured silver and platinum modified carbon fiber microelectrodes coated with nafion for H2O2 determination

    Directory of Open Access Journals (Sweden)

    Vladimir Halouzka

    2010-12-01

    Full Text Available Carbon fiber microelectrodes equipped with nanostructured metals(platinum and silver and covered with a Nafion layer constitutesensitive H2O2 sensors. Metallic layers on carbon fibers wereprepared by surfactant assisted electrodeposition. In the case ofsilver, the procedure leads to coating which is composed of porous,partially aggregated and crystalline deposits containing silvernanoparticles. The electrodeposition of platinum leads to carbonfiber decorated with clusters of platinum nanoparticles. Aftercoating the electrodes with protective and antiinterference barriermade of Nafion, the sensing properties of the preparedmicroelectrodes towards hydrogen peroxide are investigated.

  19. Cross-reactivity of Halogenated Platinum Salts

    Science.gov (United States)

    Halogenated platinum (Pt) salts are well-known respiratory sensitizers associated with the development of asthma. People may be exposed to a variety of platinum compounds in different contexts (e.g. occupationally, automobile exhaust). Published reports suggest that sensitizati...

  20. Beam localization in HIFU temperature measurements using thermocouples, with application to cooling by large blood vessels.

    Science.gov (United States)

    Dasgupta, Subhashish; Banerjee, Rupak K; Hariharan, Prasanna; Myers, Matthew R

    2011-02-01

    Experimental studies of thermal effects in high-intensity focused ultrasound (HIFU) procedures are often performed with the aid of fine wire thermocouples positioned within tissue phantoms. Thermocouple measurements are subject to several types of error which must be accounted for before reliable inferences can be made on the basis of the measurements. Thermocouple artifact due to viscous heating is one source of error. A second is the uncertainty regarding the position of the beam relative to the target location or the thermocouple junction, due to the error in positioning the beam at the junction. This paper presents a method for determining the location of the beam relative to a fixed pair of thermocouples. The localization technique reduces the uncertainty introduced by positioning errors associated with very narrow HIFU beams. The technique is presented in the context of an investigation into the effect of blood flow through large vessels on the efficacy of HIFU procedures targeted near the vessel. Application of the beam localization method allowed conclusions regarding the effects of blood flow to be drawn from previously inconclusive (because of localization uncertainties) data. Comparison of the position-adjusted transient temperature profiles for flow rates of 0 and 400ml/min showed that blood flow can reduce temperature elevations by more than 10%, when the HIFU focus is within a 2mm distance from the vessel wall. At acoustic power levels of 17.3 and 24.8W there is a 20- to 70-fold decrease in thermal dose due to the convective cooling effect of blood flow, implying a shrinkage in lesion size. The beam-localization technique also revealed the level of thermocouple artifact as a function of sonication time, providing investigators with an indication of the quality of thermocouple data for a given exposure time. The maximum artifact was found to be double the measured temperature rise, during initial few seconds of sonication.

  1. Effect of the Thermocouple on Measuring the Temperature Discontinuity at a Liquid-Vapor Interface.

    Science.gov (United States)

    Kazemi, Mohammad Amin; Nobes, David S; Elliott, Janet A W

    2017-07-18

    The coupled heat and mass transfer that occurs in evaporation is of interest in a large number of fields such as evaporative cooling, distillation, drying, coating, printing, crystallization, welding, atmospheric processes, and pool fires. The temperature jump that occurs at an evaporating interface is of central importance to understanding this complex process. Over the past three decades, thermocouples have been widely used to measure the interfacial temperature jumps at a liquid-vapor interface during evaporation. However, the reliability of these measurements has not been investigated so far. In this study, a numerical simulation of a thermocouple when it measures the interfacial temperatures at a liquid-vapor interface is conducted to understand the possible effects of the thermocouple on the measured temperature and features in the temperature profile. The differential equations of heat transfer in the solid and fluids as well as the momentum transfer in the fluids are coupled together and solved numerically subject to appropriate boundary conditions between the solid and fluids. The results of the numerical simulation showed that while thermocouples can measure the interfacial temperatures in the liquid correctly, they fail to read the actual interfacial temperatures in the vapor. As the results of our numerical study suggest, the temperature jumps at a liquid-vapor interface measured experimentally by using a thermocouple are larger than what really exists at the interface. For a typical experimental study of evaporation of water at low pressure, it was found that the temperature jumps measured by a thermocouple are overestimated by almost 50%. However, the revised temperature jumps are still in agreement with the statistical rate theory of interfacial transport. As well as addressing the specific application of the liquid-vapor temperature jump, this paper provides significant insight into the role that heat transfer plays in the operation of thermocouples

  2. Synthesis of platinum nanoparticle electrocatalysts by atomic layer deposition

    Science.gov (United States)

    Lubers, Alia Marie

    Demand for energy continues to increase, and without alternatives to fossil fuel combustion the effects on our environment will become increasingly severe. Fuel cells offer a promising improvement on current methods of energy generation; they are able to convert hydrogen fuel into electricity with a theoretical efficiency of up to 83% and interface smoothly with renewable hydrogen production. Fuel cells can replace internal combustion engines in vehicles and are used in stationary applications to power homes and businesses. The efficiency of a fuel cell is maximized by its catalyst, which is often composed of platinum nanoparticles supported on carbon. Economical production of fuel cell catalysts will promote adoption of this technology. Atomic layer deposition (ALD) is a possible method for producing catalysts at a large scale when employed in a fluidized bed. ALD relies on sequential dosing of gas-phase precursors to grow a material layer by layer. We have synthesized platinum nanoparticles on a carbon particle support (Pt/C) by ALD for use in proton exchange membrane fuel cells (PEMFCs) and electrochemical hydrogen pumps. Platinum nanoparticles with different characteristics were deposited by changing two chemistries: the carbon substrate through functionalization; and the deposition process by use of either oxygen or hydrogen as ligand removing reactants. The metal depositing reactant was trimethyl(methylcyclopentadienyl)platinum(IV). Functionalizing the carbon substrate increased nucleation during deposition resulting in smaller and more dispersed nanoparticles. Use of hydrogen produced smaller nanoparticles than oxygen, due to a gentler hydrogenation reaction compared to using oxygen's destructive combustion reaction. Synthesized Pt/C materials were used as catalysts in an electrochemical hydrogen pump, a device used to separate hydrogen fuel from contaminants. Catalysts deposited by ALD on functionalized carbon using a hydrogen chemistry were the most

  3. The extractive metallurgy of south africa's platinum ores

    Science.gov (United States)

    Cramer, Larry A.

    2001-10-01

    The extraction technology for platinum-group metals (PGMs) has changed dramatically in the last 80 years, and the changes are likely to continue for years to come. This article will review advances in PGM extraction, including developments in semi-autogenous and fully autogenous milling; flotation equipment applications for treating high-chrome ores; increases in power densities for future smelting furnaces, and new methods for meeting rising environmental standards.

  4. Fabrication and Characteristics of Thermocouple Temperature Measuring Cutter for Cutting Zone%切削区热电偶测温刀具的制备及其性能测试

    Institute of Scientific and Technical Information of China (English)

    刘志军; 林新贵; 全燕鸣

    2015-01-01

    由于切削测温温感器无法直接接触切削区,故在铂铑丝表面喷涂耐热绝缘层制作耐热热电偶,把表面覆盖耐热绝缘层的热电偶埋入硬质合金粉末,压制、烧结成热电偶测温刀片。通过恒温箱测温实验判定热电偶的测温性能,用性能正常的热电偶测温刀具进行切削测温实验,测温实验结果及切削刀具镜测结果表明,热电偶测温刀具能直接、可靠地进行切削区温度的测量,但是用此工艺制作的刀具切削寿命较短;实验结果还表明直径越大的铂铑丝制作的热电偶测温刀具的成品率越高,但是铂铑丝直径越大,刀具寿命越短;实验进一步揭示切削区内各点的温差较大,但是一次切削切削区温度场处于稳态时切削测温点的温度是稳定的,温度场处于稳态时切削温度的变化能迅速反映刀具的磨损状态的变化。%Cutting temperature measurement sensor could not directly contact the cutting zone,for resolving this problem,a heat-resistant insulation layer was sprayed on the surface of platinum rhodi-um wire so as to form the heat-resistant thermocouple initially,and then,the thermocouple covered by a heat insulation layer was embedded into the cemented carbide powder,and pressed and sintered to form a thermocouple temperature measuring blade.Temperature measuring performance of thermo-couple was judged by the temperature measurement experiments in thermostat,and the normal ther-mocouple temperature measuring cutter was used in the experiments of cutting temperature measure-ment.The experiments show that the thermocouple temperature measuring cutter can take the tem-perature measurement of the cutting zone directly and reliably,but the life of cutter is short.Experi-ments also show that the larger the diameter of platinum rhodium wire,the higher yield of the ther-mocouple temperature measuring cutter,but accordingly,the life of cutter is shorter.Experiments fur

  5. ICP-MS Determination of Platinum Metals in Black Shale Enriched by Tin Fire Assay%锡试金富集-电感耦合等离子体质谱法测定黑色页岩中的铂族元素

    Institute of Scientific and Technical Information of China (English)

    王君玉; 孙自军; 袁润蕾; 王盈; 李杰; 王敏捷

    2013-01-01

    黑色页岩中的铂族元素经锡试金富集后,所得贵金属沉淀物用盐酸-硝酸(3+1)混合酸溶解,用电感耦合等离子体质谱法测定样品中的铂族元素.以镥为内标元素,用轻质氧化镁-高纯碳化硅(2+1)作覆盖剂,以防止锇和钌的挥发损失.铂族元素在一定的质量浓度范围内与其光谱强度呈线性关系,检出限(3σ)在0.018~0.20 ng· g-1之间.方法的加标回收率在80.0%~110%之间,相对标准偏差(n=11)在5.9%~14%之间.%Platinum metals in black shale were enriched by the method of tin fire assay.The precious metal precipitate obtained was dissolved in mixed acid of HCl-HNC3 (3 + 1),and contents of platinum metals in the solution were determined by ICP-MS.Lutetium was used as internal standard; and a mixture of light MgO and high purity SiC (2 + 1) was used as covering reagent to avoid the volatilization of Os and Ru.Linear relationships between values of spectral intensity and mass concentration of the platinum metals were kept in definite ranges.Detection limits (3σ) found were in the range of 0.018-0.20 ng · g-1.Tests for recovery were made by standard addition method,giving values of recovery in the range of 80.0%-110% with RSD's (n=11) in the range of 5.9%-14%.

  6. Platinum Complexes with Edda (Ethylenediamine -N, N - Diacetate Ligands as Potential Anticancer Agents

    Directory of Open Access Journals (Sweden)

    Jurisevic Milena

    2016-12-01

    Full Text Available The design of platinum based drugs is not a new field of interest. Platinum complexes are widely used as anticancer agents and currently, approximately 30 platinum(II and platinum(IV entered into some of the phases of clinical trials. A special place in today’s research belongs to platinum complexes with diammine ligands. A large number of edda (ethylenediamine- N, N’-diacetate-type ligands and their corresponding metal complexes has been successfully synthesized. This article summarizes recent progress in research on edda-type-platinum complexes. Some of these agents achieves better effect compared to the gold standard (cisplatin. It has been shown that there is a possible relationship between the length of the ligand ester group carbon chain and its cytotoxic effect. In most cases the longer the ester chain is the greater is the antitumor activity. Of particular interest are the noticeable effects of some new platinum compound with edda-type ligand on cell lines that are known to have a high level of cisplatin-resistance. Exanimate complexes appear to have a different mode of mechanism of action compared with cisplatin which includes apoptotic and necrotic cell death. There are indications that further investigations of these compounds may be very useful in overcoming the problems associated global cancer statistic.

  7. Responses of fibroblasts and glial cells to nanostructured platinum surfaces

    Science.gov (United States)

    Pennisi, C. P.; Sevcencu, C.; Dolatshahi-Pirouz, A.; Foss, M.; Lundsgaard Hansen, J.; Nylandsted Larsen, A.; Zachar, V.; Besenbacher, F.; Yoshida, K.

    2009-09-01

    The chronic performance of implantable neural prostheses is affected by the growth of encapsulation tissue onto the stimulation electrodes. Encapsulation is associated with activation of connective tissue cells at the electrode's metallic contacts, usually made of platinum. Since surface nanotopography can modulate the cellular responses to materials, the aim of the present work was to evaluate the 'in vitro' responses of connective tissue cells to platinum strictly by modulating its surface nanoroughness. Using molecular beam epitaxy combined with sputtering, we produced platinum nanostructured substrates consisting of irregularly distributed nanopyramids and investigated their effect on the proliferation, cytoskeletal organization and cellular morphology of primary fibroblasts and transformed glial cells. Cells were cultured on these substrates and their responses to surface roughness were studied. After one day in culture, the fibroblasts were more elongated and their cytoskeleton less mature when cultured on rough substrates. This effect increased as the roughness of the surface increased and was associated with reduced cell proliferation throughout the observation period (4 days). Morphological changes also occurred in glial cells, but they were triggered by a different roughness scale and did not affect cellular proliferation. In conclusion, surface nanotopography modulates the responses of fibroblasts and glial cells to platinum, which may be an important factor in optimizing the tissue response to implanted neural electrodes.

  8. Bioavailability of very finely distributed metallic platinum in the lungs and first orienting studies on effects. Part 2; Bioverfuegbarkeit von feinstverteiltem metallischem Platin in der Lunge und erste orientierende Wirkungsuntersuchungen (VPT 09; 2. Teil)

    Energy Technology Data Exchange (ETDEWEB)

    Emmendoerffer, A. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung, Hannover (Germany)

    1997-12-31

    Platinum is emitted from automotive catalytic converters in particulate form. The first organ to be exposed to it after its uptake by the organism is the lung. Lung macrophages therefore constitute the first barrier of the immune system which can to react to platinum. In this study the production of nitrogen oxides and cytokines was studied. These parameters play an important role in the initiation of inflammation and in the maintenance of chronic inflammatory processes that can lead to fibrosis of the lung. [Deutsch] Platin wird partikulaer aus Automobilabgaskatalysatoren emittiert. Das erste Zielorgan fuer eine Aufnahme im Organismus ist deshalb die Lunge. Die Lungenmakrophagen stellen also die erste Barriere des Immunsystems dar, das auf Platin reagieren kann. In vitro wurde die Produktion von Stickoxiden und Zytokinen untersucht. Diese Parameter spielen eine Rolle bei der Initiation von Entzuendungen und auch bei der Aufrechterhaltung chronisch entzuendlicher Prozesse, die in der Lunge zu einer Fibrose fuehren koennen. (orig.)

  9. Long term out-of-pile thermocouple tests in conditions representative for nuclear gas-cooled high temperature reactors

    OpenAIRE

    LAURIE Mathias; FOURREZ Stéphane; FUETTERER Michael; LAPETITE Jean-Marc; SADLI M.; MORICE Ronan; FAILLEAU G

    2013-01-01

    During irradiation tests at high temperature failure of commercial Inconel 600 sheathed thermocouples is commonly encountered. As instrumentation, in particular thermocouples are considered safety-relevant both for irradiation tests and for commercial reactors, JRC and THERMOCOAX joined forces to solve this issue by performing out-of-pile tests with thermocouples mimicking the environment encountered by high temperature reactor (HTR) in-core instrumentation. The objective was to screen innova...

  10. Long Term Out-of-pile Thermocouple Tests in Conditions Representative for Nuclear Gas-cooled High Temperature Reactors

    OpenAIRE

    LAURIE Mathias; FOURREZ Stephane; FUETTERER Michael; LAPETITE Jean-Marc

    2011-01-01

    During irradiation tests at high temperature, failure of commercial Inconel 600 sheathed thermocouples is commonly encountered. To understand and remediate this problem, out-ofpile tests were performed with thermocouples in carburizing atmospheres which can be assumed to be at least locally representative for High Temperature Reactors. The objective was to screen those thermocouples which would consecutively be used under irradiation. Two such screening tests have been performed with a set of...

  11. Measurement of Thermocouple Time Constant%热电偶时间常数的测量

    Institute of Scientific and Technical Information of China (English)

    傅元; 董宇哲; 李德健; 董健

    2012-01-01

    为准确测量出热电偶的时间常数,根据热电偶对阶跃温度的响应,用单指数曲线描述过渡过程的数学模型,对记录的过渡过程曲线进行拟合,拟合后单指数曲线的时间常数就是被测热电偶的时间常数。对多种热电偶和同一热电偶的反复测试表明这种方法准确,相对于其它方法适应性更强。%In order to accurately measure the time constant of the thermocouple, according to the temperature of the thermocouple to a step response, single exponential curve with a mathematical model of the transition process described, record of the transition pro- cess of fitting curves, after fitting a single exponential curve is the measured time constant time constant thermocouples. A variety of thermocouples and thermocouple repeated the same test shows that this method is accurate, compared to other methods more adaptive.

  12. Photophysics of organometallic platinum(II) derivatives of the diketopyrrolopyrrole chromophore

    KAUST Repository

    Goswami, Subhadip

    2014-12-18

    A pair of diketopyrrolopyrrole (DPP) chromophores that are end-functionalized with platinum containing "auxochromes" were subjected to electrochemical and photophysical study. The chromophores contain either platinum acetylide or ortho-metalated 2-thienylpyridinyl(platinum) end-groups (DPP-Pt(CC) and DPP-Pt(acac), respectively). The ground state redox potentials of the chromophores were determined by solution electrochemistry, and the HOMO and LUMO levels were estimated. The chromophores\\' photophysical properties were characterized by absorption, photoluminescence, and time-resolved absorption spectroscopy on time scales from sub-picoseconds to microseconds. Density functional theory (DFT) computations were performed to understand the molecular orbitals involved in both the singlet and triplet excited state photophysics. The results reveal that in both platinum DPP derivatives the organometallic auxochromes have a significant effect on the chromophores\\' photophysics. The most profound effect is a reduction in the fluorescence yields accompanied by enhanced triplet yields due to spin-orbit coupling induced by the metal centers. The effects are most pronounced in DPP-Pt(acac), indicating that the orthometalated platinum auxochrome is able to induce spin-orbital coupling to a greater extent compared to the platinum acetylide units. (Figure Presented).

  13. Selective speciation improves efficacy and lowers toxicity of platinum anticancer and vanadium antidiabetic drugs.

    Science.gov (United States)

    Doucette, Kaitlin A; Hassell, Kelly N; Crans, Debbie C

    2016-12-01

    Improving efficacy and lowering resistance to metal-based drugs can be addressed by consideration of the coordination complex speciation and key reactions important to vanadium antidiabetic drugs or platinum anticancer drugs under biological conditions. The methods of analyses vary depending on the specific metal ion chemistry. The vanadium compounds interconvert readily, whereas the reactions of the platinum compounds are much slower and thus much easier to study. However, the vanadium species are readily differentiated due to vanadium complexes differing in color. For both vanadium and platinum systems, understanding the processes as the compounds, Lipoplatin and Satraplatin, enter cells is needed to better combat the disease; there are many cellular metabolites, which may affect processing and thus the efficacy of the drugs. Examples of two formulations of platinum compounds illustrate how changing the chemistry of the platinum will result in less toxic and better tolerated drugs. The consequence of the much lower toxicity of the drug, can be readily realized because cisplatin administration requires hospital stay whereas Lipoplatin can be done in an outpatient manner. Similarly, the properties of Satraplatin allow for development of an oral drug. These forms of platinum demonstrate that the direct consequence of more selective speciation is lower side effects and cheaper administration of the anticancer agent. Therefore we urge that as the community goes forward in development of new drugs, control of speciation chemistry will be considered as one of the key strategies in the future development of anticancer drugs.

  14. Synthesis and characterisation of platinum (II) salphen complex and its interaction with calf thymus DNA

    Energy Technology Data Exchange (ETDEWEB)

    Sukri, Shahratul Ain Mohd; Heng, Lee Yook; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43650 Bangi, Selangor (Malaysia)

    2014-09-03

    A platinum (II) salphen complex was synthesised by condensation reaction of 2,4-dihydroxylbenzaldehyde and o-phenylenediamine with potassium tetrachloroplatinate to obtain N,N′-Bis-4-(hydroxysalicylidene)-phenylenediamine-platinum (II). The structure of the complex was confirmed by {sup 1}H and {sup 13}C NMR spectroscopy, FTIR spectroscopy, CHN elemental analyses and ESI-MS spectrometry. The platinum (II) salphen complex with four donor atoms N{sub 2}O{sub 2} from its salphen ligand coordinated to platinum (II) metal centre were determined. The binding mode and interaction of this complex with calf thymus DNA was determined by UV/Vis DNA titration and emission titration. The intercalation between the DNA bases by π-π stacking due to its square planar geometry and aromatic rings structures was proposed.

  15. Synthesis and characterisation of platinum (II) salphen complex and its interaction with calf thymus DNA

    Science.gov (United States)

    Sukri, Shahratul Ain Mohd; Heng, Lee Yook; Karim, Nurul Huda Abd

    2014-09-01

    A platinum (II) salphen complex was synthesised by condensation reaction of 2,4-dihydroxylbenzaldehyde and o-phenylenediamine with potassium tetrachloroplatinate to obtain N,N'-Bis-4-(hydroxysalicylidene)-phenylenediamine-platinum (II). The structure of the complex was confirmed by 1H and 13C NMR spectroscopy, FTIR spectroscopy, CHN elemental analyses and ESI-MS spectrometry. The platinum (II) salphen complex with four donor atoms N2O2 from its salphen ligand coordinated to platinum (II) metal centre were determined. The binding mode and interaction of this complex with calf thymus DNA was determined by UV/Vis DNA titration and emission titration. The intercalation between the DNA bases by π-π stacking due to its square planar geometry and aromatic rings structures was proposed.

  16. Tungsten/Platinum Hybrid Nanowire Growth via Field Emission Using Nanorobotic Manipulation

    Directory of Open Access Journals (Sweden)

    Zhan Yang

    2011-01-01

    Full Text Available This paper reports tungsten-platinum hybrid nanowire growth via field emission, based on nanorobotic manipulation within a field emission scanning electron microscope (FESEM. A multiwalled carbon nanotube (MWCNT was used as the emitter, and a tungsten probe was used as the anode at the counterposition, by way of nanomanipulation. By independently employing trimethylcyclopentadienyl platinum (CpPtMe3 and tungsten hexacarbonyl (W(CO6 as precursors, the platinum nanowire grew on the tip of the MWCNT emitter. Tungsten nanowires then grew on the tip of the platinum nanowire. The hybrid nanowire length wascontrolled by nanomanipulation. Their purity was evaluated using energy-dispersive X-ray spectroscopy (EDS. Thus, it is possible to fabricate various metallic hybrid nanowires by changing the precursor materials. Hybrid nanowires have various applications in nanoelectronics, nanosensor devices, and nanomechanical systems.

  17. Bioinspired hierarchical nanotubular titania immobilized with platinum nanoparticles for photocatalytic hydrogen production.

    Science.gov (United States)

    Liu, Xiaoyan; Li, Jiao; Zhang, Yiming; Huang, Jianguo

    2015-05-11

    A bioinspired nanocomposite composed of platinum nanoparticles and nanotubular titania was fabricated in which the titania matter was templated by natural cellulose substance. The composite possesses three- dimensional hierarchical structures, and ultrafine metallic platinum particles with sizes of ca. 2 nm were immobilized uniformly on the surfaces of the titania nanotubes. Such a nanocomposite with 1.06 wt % of platinum content shows the optimal photocatalytic hydrogen production activity from water splitting of 16.44 mmol h(-1)  g(-1) , and excessive loading of platinum results in poorer photocatalytic performance. The structural integrity of the nanocomposite upon cyclic water-splitting processes results in its sufficient photocatalytic stability.

  18. Synthesis and photophysical and electrochemical properties of new cyclometalated platinum complex containing oxadiazole ligand

    Institute of Scientific and Technical Information of China (English)

    DENG Ji-yong; LIU Yu; HU Zheng-yong; ZHU Mei-xiang; ZHU Wei-guo

    2007-01-01

    A new cyclometalated platinum complex containing 2, 5-bis(naphthalene-1-y1)-1,3,4-oxadiazole ligand was synthesized and characterized. The UV-Vis absorptions and photoluminescent properties of the ligand and its platinum complex were investigated.A characteristic metal-ligand charge transfer absorption peak at 439 nm in the UV spectrum and a strong emission peak at 625 nm in the photoluminescence spectrum were observed for this complex in dichloromethane. Cyclic voltammtry (CV) analysis shows that the EHOMO (energy level of the highest occupied molecular orbital) and ELUMO (energy level of the lowest unoccupied molecular orbital) of the platinum complex are about -5.69 and -3.25 eV, respectively, indicating that the oxadiazole-based platinum complex has a potential application in electrophosphorescent devices used as a red-emitting material.

  19. Thermocouples--the Arizona experience with in-house manufactured probes.

    Science.gov (United States)

    Anhalt, D; Hynynen, K

    1992-01-01

    The performance of several different types of multisensor thermocouple probes have been tested to determine the feasibility of each type for use in the hyperthermia clinic. All of the probes tested were manufactured in-house, and a detailed description of the construction process will be presented. The overall performance of the probes in terms of robustness, calibration, conduction errors, and response time will be described. In particular, this study describes our experience with in-house manufactured thermocouples over the past several years. The results indicate that when strict quality assurance guidelines are followed, in-house manufactured thermocouples perform satisfactorily--thereby providing an alternative to purchasing probes and measurement systems from commercial vendors if the proper resources are available.

  20. Direct measurements of electrocaloric effect in ferroelectrics using thin-film thermocouples

    Science.gov (United States)

    Matsushita, Yuji; Nochida, Atsushi; Yoshimura, Takeshi; Fujimura, Norifumi

    2016-10-01

    A direct measurement method for investigating the electrocaloric (EC) effect was developed using a thin-film thermocouple deposited on samples. A T-type thin-film thermocouple was fabricated by RF magnetron sputtering at room temperature. Two types of measurement were carried out using rectangular pulses and sine waves with a DC offset. The EC coefficients (ΔT/ΔE) of BaTiO3 ceramics were determined as 0.35 × 10-6 and 0.48 × 10-6 K·m/V in the measurements at Curie temperature. The EC temperature change of a (Ba0.9,Ca0.1)TiO3 thin film was measured using sine waves with the DC offset. The EC coefficient was 0.0018 × 10-6 K·m/V at room temperature. These results suggest that thin-film thermocouples are useful for the direct measurement of the EC effect.

  1. Nanocarriers for delivery of platinum anticancer drugs☆

    Science.gov (United States)

    Oberoi, Hardeep S.; Nukolova, Natalia V.; Kabanov, Alexander V.; Bronich, Tatiana K.

    2014-01-01

    Platinum based anticancer drugs have revolutionized cancer chemotherapy, and continue to be in widespread clinical use especially for management of tumors of the ovary, testes, and the head and neck. However, several dose limiting toxicities associated with platinum drug use, partial anti-tumor response in most patients, development of drug resistance, tumor relapse, and many other challenges have severely limited the patient quality of life. These limitations have motivated an extensive research effort towards development of new strategies for improving platinum therapy. Nanocarrier-based delivery of platinum compounds is one such area of intense research effort beginning to provide encouraging preclinical and clinical results and may allow the development of the next generation of platinum chemotherapy. This review highlights current understanding on the pharmacology and limitations of platinum compounds in clinical use, and provides a comprehensive analysis of various platinum–polymer complexes, micelles, dendrimers, liposomes and other nanoparticles currently under investigation for delivery of platinum drugs. PMID:24113520

  2. The Versatile Behavior of Platinum Alkyne Complexes towards XeF2 : Formation of Fluorovinyl and Fluorido Complexes.

    Science.gov (United States)

    Berger, Josefine; Braun, Thomas; Ahrens, Theresia; Kläring, Paul; Laubenstein, Reik; Braun-Cula, Beatrice

    2017-07-03

    Reactions of platinum(0) tolane complexes, bearing a chelating ligand with P and N donor atoms, with the electrophilic fluorinating agent XeF2 give facile access to platinum(II) β-fluorovinyl fluorido complexes. A series of new platinum(II) β-fluorovinyl complexes have been synthesized and were structurally characterized. Further oxidation with XeF2 led to ortho-metalated platinum(IV) fluorido compounds. Additional reactions of platinum(0) tolane complexes, bearing a chelating P,P donor ligand, with XeF2 led to a variety of fluorido and fluorovinyl complexes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Thermocouple error correction for measuring the flame temperature with determination of emissivity and heat transfer coefficient.

    Science.gov (United States)

    Hindasageri, V; Vedula, R P; Prabhu, S V

    2013-02-01

    Temperature measurement by thermocouples is prone to errors due to conduction and radiation losses and therefore has to be corrected for precise measurement. The temperature dependent emissivity of the thermocouple wires is measured by the use of thermal infrared camera. The measured emissivities are found to be 20%-40% lower than the theoretical values predicted from theory of electromagnetism. A transient technique is employed for finding the heat transfer coefficients for the lead wire and the bead of the thermocouple. This method does not require the data of thermal properties and velocity of the burnt gases. The heat transfer coefficients obtained from the present method have an average deviation of 20% from the available heat transfer correlations in literature for non-reacting convective flow over cylinders and spheres. The parametric study of thermocouple error using the numerical code confirmed the existence of a minimum wire length beyond which the conduction loss is a constant minimal. Temperature of premixed methane-air flames stabilised on 16 mm diameter tube burner is measured by three B-type thermocouples of wire diameters: 0.15 mm, 0.30 mm, and 0.60 mm. The measurements are made at three distances from the burner tip (thermocouple tip to burner tip/burner diameter = 2, 4, and 6) at an equivalence ratio of 1 for the tube Reynolds number varying from 1000 to 2200. These measured flame temperatures are corrected by the present numerical procedure, the multi-element method, and the extrapolation method. The flame temperatures estimated by the two-element method and extrapolation method deviate from numerical results within 2.5% and 4%, respectively.

  4. Thermocouple error correction for measuring the flame temperature with determination of emissivity and heat transfer coefficient

    Science.gov (United States)

    Hindasageri, V.; Vedula, R. P.; Prabhu, S. V.

    2013-02-01

    Temperature measurement by thermocouples is prone to errors due to conduction and radiation losses and therefore has to be corrected for precise measurement. The temperature dependent emissivity of the thermocouple wires is measured by the use of thermal infrared camera. The measured emissivities are found to be 20%-40% lower than the theoretical values predicted from theory of electromagnetism. A transient technique is employed for finding the heat transfer coefficients for the lead wire and the bead of the thermocouple. This method does not require the data of thermal properties and velocity of the burnt gases. The heat transfer coefficients obtained from the present method have an average deviation of 20% from the available heat transfer correlations in literature for non-reacting convective flow over cylinders and spheres. The parametric study of thermocouple error using the numerical code confirmed the existence of a minimum wire length beyond which the conduction loss is a constant minimal. Temperature of premixed methane-air flames stabilised on 16 mm diameter tube burner is measured by three B-type thermocouples of wire diameters: 0.15 mm, 0.30 mm, and 0.60 mm. The measurements are made at three distances from the burner tip (thermocouple tip to burner tip/burner diameter = 2, 4, and 6) at an equivalence ratio of 1 for the tube Reynolds number varying from 1000 to 2200. These measured flame temperatures are corrected by the present numerical procedure, the multi-element method, and the extrapolation method. The flame temperatures estimated by the two-element method and extrapolation method deviate from numerical results within 2.5% and 4%, respectively.

  5. [Formylation of porphyrin platinum complexes].

    Science.gov (United States)

    Rumiantseva, V D; Konovalenko, L I; Nagaeva, E A; Mironov, A F

    2005-01-01

    The formylation reaction of platinum complexes of beta-unsubstituted porphyrins was studied. The interaction of deuteroporphyrin IX derivatives with the Vilsmeyer reagent led to the selective formylation of their macrocycles in the beta position. The resulting formyl derivatives of the porphyrins are of interest for fluorescent immunoassay.

  6. Hydrogen as a Modifier of the Structure and Electronic Properties of Platinum in Acidic Zeolite. LTL: A Combined Infrared and X-ray Absorption Spectroscopy Study.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Vaarkamp, M.; Mojet, B.L.; Kappers, M.J.; Miller, J.T.

    1995-01-01

    The structure and electronic properties of platinum in WH-LTL after reduction at 300 'C and heating in helium to 500 or 690 'C were determined using X-ray absorption and infrared spectroscopy. After reduction at 300 'C, the platinum particles were metallic, consisted of 4 or 5 atoms, and were locate

  7. The Origin of Sulfur Tolerance in Supported Platinum Catalysts: The Relationship between Structural and Catalytic Properties in Acidic and Alkaline Pt/LTL.

    NARCIS (Netherlands)

    Koningsberger, D.C.; Miller, J.T.

    1996-01-01

    The reactivity, structure, and sulfur tolerance is compared for platinum supported on acidic and alkaline LTL zeolite. In the absence of sulfur, EXAFS spectroscopy indicates that small metallic platinum particles of approximately 6 to 14 atoms/cluster are present. The TOF for neopentane hydrogenolys

  8. Technical note. Use of CT in the placement of heat monitoring thermocouples for hyperthermia therapy.

    Science.gov (United States)

    Eftekhari, F; Bernardino, M E; Headley, D L; Corry, P M

    1981-12-01

    In 12 cancer patients undergoing hyperthermia therapy, computed tomography (CT) was used for placement of thermocouples within the tumoral tissue. Tumors were located in the thorax, abdomen, and pelvis. Computed tomography provided accurate angulation of the introduction angiocatheter as well as the ability to choose the shortest and safest path. The cross-sectional display was especially helpful in placing the heat monitoring thermocouple within the active part of the tumor rather than a necrotic portion. It is our opinion that CT is superior to fluoroscopy in this regard.

  9. Modeling of the polymerization process of the insulating layer of cable thermocouples

    Directory of Open Access Journals (Sweden)

    Olga Iashutina

    2017-01-01

    Full Text Available A mathematical model describing the main physical processes occurring during thermal processing of cable thermocouples (CT during their production is presented. The polymerization of the insulating layer is taken into account in the conditions of its intense heating. The developed mathematical model allows to carry out calculations of heat transfer processes under the conditions of substantial heterogeneity of cable thermocouple structure. The computational experiments carried out have established significant differences in the characteristics of heat transfer in CT in the presence of thermoelectrodes with differing thermophysical characteristics.

  10. A Study of the Behavior Characteristics for K-type Thermocouple

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Songhae; Kim, Yongsik; Lee, Sooill [KHNP Central Research Institute, Daejeon (Korea, Republic of); Kim, Sungjin [Woojin inc., Osan (Korea, Republic of); Lyou, Jooon [Chungnam National Univ., Daejeon (Korea, Republic of)

    2014-05-15

    K-type thermocouple is widely used in nuclear power plants (NPP) and they provide reliable service. Generally, the thermocouple assembly is the finished product and usually only nondestructive tests are performed on the assembly, whereas destructive tests are confined to selected bulk cable specimens. This K-type thermocouple has been used representatively in the In-Core Instrument Assembly (ICI) in the nuclear power plants. The ICI consists of five rhodium emitter detectors that provide information on the thermal power for the core and one K-type thermocouple made with two cables (Chromel-Alumel) that provides the temperature of core exit (CET). Generally, the quantity of the ICI is absolutely different according to the number of fuel assemblies in the NPP. In the case of SKN 3 and 4, they were designed to the 61 ICI to provide information on the core cooling to the inadequate core cooling monitoring system (ICCMS). This measured temperature could be also used to check the entry condition of severe accidents. The technology of the TFDR is a generic skill to detect the fault position of the cable. In-core Instruments (ICIs) were used to detect the Core Exit Temperature (CET) in a reactor. This measured temperature was also used to check the entry condition of severe accidents. However, if a serious accident occurs, the upper portion of the core is damaged. This instrument has not been available. This paper illustrates the estimation possibility for the status of molten core through the high-temperature characteristics test of k-type thermocouple. It turns out that it is possible to measure the k-type thermocouple up to 1350 .deg. C degrees before melting during insertion into the melting furnace. Additionally, in order to measure a high temperature of 2000 .deg. C or more, the replacement possibility of k-type thermocouple was evaluated. However the tungsten-rhenium thermocouple is impossible to use in the detection of temperature at the in-core because of the

  11. Determination of platinum traces contamination by graphite furnace atomic absorption spectrometry after preconcentration by cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chappuy, M. [Analytical Development Laboratory, Pharmaceutical Establishment of Paris Hospitals, 7 rue du Fer a Moulin, 75005 Paris (France); Caudron, E., E-mail: eric.caudron@eps.aphp.fr [Analytical Development Laboratory, Pharmaceutical Establishment of Paris Hospitals, 7 rue du Fer a Moulin, 75005 Paris (France); Groupe de Chimie Analytique de Paris-Sud, EA 4041, IFR 141, School of Pharmacy, Univ Paris-Sud, 92296 Chatenay-Malabry (France); Bellanger, A. [Department of Pharmacy, Pitie-Salpetriere Hospital (Paris Public Hospital Authority), 47 boulevard de l' hopital, 75013 Paris (France); Pradeau, D. [Analytical Development Laboratory, Pharmaceutical Establishment of Paris Hospitals, 7 rue du Fer a Moulin, 75005 Paris (France)

    2010-04-15

    A simple and sensitive method is described for the determination of platinum surface contamination originating from cisplatin, carboplatin and oxaliplatin. Following extraction from swabs and preconcentration with the cloud point extraction (CPE) method, detection was by graphite furnace atomic absorption spectrometry (GFAAS). After desorption of platinum compounds from the swab, CPE involved on preconcentration of platinum in aqueous solution with diethyldithiocarbamate (DDTC) as chelating agent and Triton X-114 as extraction medium. DDTC is not only a chelating agent, but may also be a good candidate for the inactivation of platinum compounds. DDTC is recommended by the Word Health Organization (WHO) for the destruction of platinum-based anticancer drugs. The main factors affecting CPE efficiency, pH of the sample solution, concentrations of DDTC and Triton X-114, equilibration temperature and incubation time, were evaluated in order to enhance sensitivity of the method. The desorption of platinum compounds from the swab was investigated in parallel. Since platinum is bound to DDTC, it must exchange with copper in order to enhance platinum atomizing by GFAAS. A preconcentration factor of 29 was obtained for 10 mL of a platinum solution at 10 {mu}g mL{sup -1}. In optimal conditions, the limit of detection was 0.2 ng mL{sup -1}, corresponding to 2.0 ng of platinum metal on the swab. Absorbance was linear between 0.7 and 15 ng mL{sup -1}. The proposed method was applied for the determination of surface contamination by platinum compounds with correct results.

  12. Analysis and Reflection to the Problem of Thermocouple Quantity Transfer System above 300℃%300℃以上热电偶量传体系问题分析及对策

    Institute of Scientific and Technical Information of China (English)

    刘丹英; 吕国义; 张贺

    2015-01-01

    At present, the thermocouple quantity transfer system above 300℃ has the problems that measurement uncertainties are too large and measurement capability does not satisfy the need. The new quantity transfer system based on fixed point temperature measurement was put for-ward on the basis of the latest development of high temperature eutectic point and practical fixed point temperature measurement, pure metal ther-mocouple temperature measurement, and thermocouple calibration technology above 1500℃. The new transfer system can greatly reduce the thermo-couple measuring value uncertainty, guarantee the quantity value transfer of each grade normally, and meet thermocouple traceable requirements.%针对目前300℃以上热电偶量传体系存在不确定度过大、 计量能力不满足要求等问题, 分析了高温共晶点和实用型固定点温度复现、 纯金属热电偶温度测量和1500℃以上高温热电偶校准等技术的最新进展, 提出基于固定点温度复现方法的新的量值传递体系设想, 可大大减小热电偶量值传递的不确定度, 使各级计量标准装置不确定度分布更为合理, 能保证热电偶量值的逐级量传, 满足科研生产对热电偶的溯源要求.

  13. Long term out-of-pile thermocouple tests in conditions representative for nuclear gas-cooled high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Laurie, M. [European Commission, Joint Research Centre, Inst. for Energy, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Fourrez, S. [THERMOCOAX SAS, BP 26, Planquivon, F-61438 Flers Cedex (France); Fuetterer, M. A.; Lapetite, J. M. [European Commission, Joint Research Centre, Inst. for Energy, P.O. Box 2, NL-1755 ZG Petten (Netherlands)

    2011-07-01

    During irradiation tests at high temperature, failure of commercial Inconel 600 sheathed thermocouples is commonly encountered. To understand and remedy this problem, out-of-pile tests were performed with thermocouples in carburizing atmospheres which can be assumed to be at least locally representative for High Temperature Reactors. The objective was to screen those thermocouples which would consecutively be used under irradiation. Two such screening tests have been performed with a set of thermocouples embedded in graphite (mainly conventional Type N thermocouples and thermocouples with innovative sheaths) in a dedicated furnace with helium flushing. Performance indicators such as thermal drift, insulation and loop resistance were monitored and compared to those from conventional Type N thermocouples. Several parameters were investigated: niobium sleeves, bending, thickness, sheath composition, temperature as well as the chemical environment. After the tests, Scanning Electron Microscopy (SEM) examinations were performed to analyze possible local damage in wires and in the sheath. The present paper describes the two experiments, summarizes results and outlines further work, in particular to further analyze the findings and to select suitable thermocouples for qualification under irradiation. (authors)

  14. Modification of platinum surfaces by spontaneous deposition: Methanol oxidation electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, J.P.; Gualtieri, B.; Runga, N.; Teliz, E.; Zinola, C.F. [Fundamental Electrochemistry Laboratory, School of Sciences, Universidad de la Republica, Igua Street No. 4225, CP 11400, Montevideo (Uruguay)

    2008-12-15

    The presence of a second metal on platinum surfaces affects the performance of methanol oxidation. However, most of the electrocatalytic reactions are studied by using electrochemically deposited platinum alloys, but in the case of spontaneous deposition the situation is not so clear since the surface distribution, stability and morphology are usually not well documented. The formation of surface decorated samples on mono- and poly-crystalline platinum is followed by electrochemical and spectroscopic techniques and analysis of their performance towards methanol adsorption and oxidation compared with that on pure platinum. Pt/Sn and Pt/Ru are of special interest because of their well-known performance in methanol fuel cells. Methanol oxidation on Pt(111)/Ru, Pt(111)/Sn and Pt(111) shows that ruthenium is the only one able to promote the reaction since the simultaneous dissolution of tin occurs and competes with the process of interest. The in situ infrared spectroscopy is used to compare methanol oxidation on Pt(111)/Ru and Pt(111) in acid media using p-polarized light. The formation of bridge bound carbon monoxide is inhibited in the presence of ruthenium ad-species, whereas on Pt(111) the three adsorption configurations are observed. Linear sweep polarization curves and Tafel slopes (calculated from steady state potentiostatic plots) for methanol oxidation are compared on polycrystalline surfaces modified by tin or ruthenium at different coverages. There is almost no change in the Tafel slopes due to the presence of the foreign metal except for Pt/Ru, where a 0.09 V decade{sup -1} slope was calculated below 0.55 V due to hydroxyl adsorbates on ruthenium islands. The anodic stripping of methanol residues on the three surfaces indicates a lower amount of carbon monoxide-type adsorbates on Pt/Ru, and the simultaneous tin dissolution process leading to residues oxidation on Pt/Sn electrodes. (author)

  15. Performance and Durability of Thin Film Thermocouple Array on a Porous Electrode.

    Science.gov (United States)

    Guk, Erdogan; Ranaweera, Manoj; Venkatesan, Vijay; Kim, Jung-Sik

    2016-08-23

    Management of solid oxide fuel cell (SOFC) thermal gradients is vital to limit thermal expansion mismatch and thermal stress. However, owing to harsh operation conditions of SOFCs and limited available space in stack configuration, the number of techniques available to obtain temperature distribution from the cell surface is limited. The authors previously developed and studied a thermocouple array pattern to detect surface temperature distribution on an SOFC in open circuit conditions. In this study, the performance in terms of mechanical durability and oxidation state of the thin film thermoelements of the thermocouple array on the porous SOFC cathode is investigated. A thin-film multi-junction thermocouple array was sputter deposited using a magnetron sputter coater. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) characterisation techniques were carried out to understand characteristics of the thin film before and after temperature (20 °C-800 °C) measurement. Temperature readings from the sensor agreed well with the closely placed commercial thermocouple during heating segments. However, a sensor failure occurred at around 350 °C during the cooling segment. The SEM and XPS tests revealed cracks on the thin film thermoelements and oxidation to the film thickness direction.

  16. Measuring skin temperature before, during and after exercise: a comparison of thermocouples and infrared thermography.

    Science.gov (United States)

    Fernandes, Alex de Andrade; Amorim, Paulo Roberto dos Santos; Brito, Ciro José; de Moura, Anselmo Gomes; Moreira, Danilo Gomes; Costa, Carlos Magno Amaral; Sillero-Quintana, Manuel; Marins, João Carlos Bouzas

    2014-02-01

    Measuring skin temperature (TSK) provides important information about the complex thermal control system and could be interesting when carrying out studies about thermoregulation. The most common method to record TSK involves thermocouples at specific locations; however, the use of infrared thermal imaging (IRT) has increased. The two methods use different physical processes to measure TSK, and each has advantages and disadvantages. Therefore, the objective of this study was to compare the mean skin temperature (MTSK) measurements using thermocouples and IRT in three different situations: pre-exercise, exercise and post-exercise. Analysis of the residual scores in Bland-Altman plots showed poor agreement between the MTSK obtained using thermocouples and those using IRT. The averaged error was -0.75 °C during pre-exercise, 1.22 °C during exercise and -1.16 °C during post-exercise, and the reliability between the methods was low in the pre- (ICC = 0.75 [0.12 to 0.93]), during (ICC = 0.49 [-0.80 to 0.85]) and post-exercise (ICC = 0.35 [-1.22 to 0.81] conditions. Thus, there is poor correlation between the values of MTSK measured by thermocouples and IRT pre-exercise, exercise and post-exercise, and low reliability between the two forms of measurement.

  17. Temperature measurement artefacts of thermocouples and fluoroptic probes during laser irradiation at 810 nm.

    Science.gov (United States)

    Reid, A D; Gertner, M R; Sherar, M D

    2001-06-01

    This study examined the artefact induced in temperature measurements made with thermocouples and Luxtron fluoroptic probes in the presence of infrared radiation. Localized heating was created using a continuous-wave, 810 nm diode laser system emitting 2.0 W from a cylindrical diffusing optical fibre, in air, water and an agar-albumin phantom. The temperature was measured every 1.0 s for 10 to 150 s, with both a thermocouple and a Luxtron fluoroptic probe at distances of 2, 3, 4, 5, 6 and 7 mm from the cylindrical diffusing tip. In all cases, the fluoroptic probe recorded a higher temperature than the thermocouple during laser irradiation. The difference in measured temperatures between the Luxtron probe and the thermocouple ranged from 1.6 degrees C to 18.8 degrees C in air, from 0.3 degrees C to 10.2 degrees C in water, and from 1.4 degrees C to 10.1 degrees C in phantom, depending on the distance of the probe from the laser source. The results suggest that in the presence of laser irradiation, self-heating of the Luxtron probe induces a significant artefact in temperature measurements at distances less than 4 mm from the source fibre. As a result, fluoroptic probes may not be suitable for monitoring tissue temperature for treatments when laser irradiation is present if sensors are located close to the fibre tip (<4 mm).

  18. Ceramic thin film thermocouples for SiC-based ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Wrbanek, John D., E-mail: John.D.Wrbanek@nasa.gov; Fralick, Gustave C.; Zhu Dongming

    2012-06-30

    Conductive ceramic thin film thermocouples were investigated for application to silicon carbide fiber reinforced silicon carbide ceramic matrix composite (SiC/SiC CMC) components. High temperature conductive oxides based on indium and zinc oxides were selected for testing to high temperatures in air. Sample oxide films were first sputtered-deposited on alumina substrates then on SiC/SiC CMC sample disks. Operational issues such as cold junction compensation to a 0 Degree-Sign C reference, resistivity and thermopower variations are discussed. Results show that zinc oxides have an extremely high resistance and thus increased complexity for use as a thermocouple, but thermocouples using indium oxides can achieve a strong, nearly linear response to high temperatures. - Highlights: Black-Right-Pointing-Pointer Oxide thin film thermocouples tested for SiC/SiC ceramic matrix composites (CMCs) Black-Right-Pointing-Pointer In{sub 2}O{sub 3}, N:In{sub 2}O{sub 3}, ZnO, AlZnO sputtered and tested on Al{sub 2}O{sub 3} and CMC substrates Black-Right-Pointing-Pointer ZnO, AlZnO have high resistance, complex temperature response. Black-Right-Pointing-Pointer In{sub 2}O{sub 3}, N:In{sub 2}O{sub 3} conductive at room temperature, more linear temperature response.

  19. Performance and Durability of Thin Film Thermocouple Array on a Porous Electrode

    Science.gov (United States)

    Guk, Erdogan; Ranaweera, Manoj; Venkatesan, Vijay; Kim, Jung-Sik

    2016-01-01

    Management of solid oxide fuel cell (SOFC) thermal gradients is vital to limit thermal expansion mismatch and thermal stress. However, owing to harsh operation conditions of SOFCs and limited available space in stack configuration, the number of techniques available to obtain temperature distribution from the cell surface is limited. The authors previously developed and studied a thermocouple array pattern to detect surface temperature distribution on an SOFC in open circuit conditions. In this study, the performance in terms of mechanical durability and oxidation state of the thin film thermoelements of the thermocouple array on the porous SOFC cathode is investigated. A thin-film multi-junction thermocouple array was sputter deposited using a magnetron sputter coater. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) characterisation techniques were carried out to understand characteristics of the thin film before and after temperature (20 °C–800 °C) measurement. Temperature readings from the sensor agreed well with the closely placed commercial thermocouple during heating segments. However, a sensor failure occurred at around 350 °C during the cooling segment. The SEM and XPS tests revealed cracks on the thin film thermoelements and oxidation to the film thickness direction. PMID:27563893

  20. Conducting metal dithiolate complexes

    DEFF Research Database (Denmark)

    Underhill, A. E.; Ahmad, M. M.; Turner, D. J.;

    1985-01-01

    Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound...

  1. Production of Platinum Atom Nanoclusters at One End of Helical Plant Viruses

    Directory of Open Access Journals (Sweden)

    Yuri Drygin

    2013-01-01

    Full Text Available Platinum atom clusters (Pt nanoparticles, Pt-NPs were produced selectively at one end of helical plant viruses, tobacco mosaic virus (TMV and potato virus X (PVX, when platinum coordinate compounds were reduced chemically by borohydrides. Size of the platinum NPs depends on conditions of the electroless deposition of platinum atoms on the virus. Results suggest that the Pt-NPs are bound concurrently to the terminal protein subunits and the 5′ end of encapsidated TMV RNA. Thus, a special structure of tobacco mosaic virus and potato X virus particles with nanoparticles of platinum, which looks like a push-pin with platinum head and virus needle, was obtained. Similar results were obtained with ultrasonically fragmented TMV particles. By contrast, the Pt-NPs fully filled the central axial hole of in vitro assembled RNA-free TMV-like particles. We believe that the results presented here will be valuable in the fundamental understanding of interaction of viral platforms with ionic metals and in a mechanism of nanoparticles formation.

  2. Simulation of Thin Film Thermocouple for High Temperature Measurement Applicable to Missiles

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Sonker

    2015-09-01

    Full Text Available Thermocouples have been extensively used for the measurement of temperature since the advent of seebeck effect. Numerous sensors have been developed for temperature measurement, yet measurement of high temperature flowing fluid has been a challenging task. For the measurement of static temperature the measuring device should travel with the fluid at the same speed without disturbing the flow, which is quite unrealistic. So indirect determination of static temperature of flowing fluid is done by using thermocouple exposed into the flowing fluid. Other sensors available for high temperature measurement may lead to problems like resistance in the flow path of fluid which changes the structural dynamics. Thin film thermocouple (TFTC based on W-W26Re for super high temperature measurement has been investigated which can be used in missiles for surface temperature measurement of nozzle and rocket interior surface. TFTC does not cause disruption in the flow path with maintaining structural integrity. The W-W26Re thermocouple offers advantage of higher seebeck coefficient at high temperature i.e. above 750 K, and usability in vacuum, inert and hydrogen atmosphere. Zirconia Fiber has been proposed as insulation protection material over thermocouple. Modelling and simulation of the TFTC for the temperature range 300 K - 2900 K has been presented. FEA model using PDE has been presented to implement heat equation, current balance  quation, Gauss theorem and Neumann boundary condition. The expected voltage production on exposed temperature gradient has been studied.

  3. Surface characterization of platinum electrodes.

    Science.gov (United States)

    Solla-Gullón, José; Rodríguez, Paramaconi; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M

    2008-03-14

    The quantitative analysis of the different surface sites on platinum samples is attempted from pure voltammetric data. This analysis requires independent knowledge of the fraction of two-dimensional (111) and (100) domains. Specific site-probe reactions are employed to achieve this goal. Irreversibly-adsorbed bismuth and tellurium have been revealed to be sensitive to the presence of (111) terrace domains of different width whereas almost all sites involved in (100) ordered domains have been characterized through germanium adatoms. The experimental protocol follows that used with well-defined single-crystal electrodes and, therefore, requires careful control of the surface cleanliness. Platinum basal planes and their vicinal stepped surfaces have been employed to obtain calibration plots between the charge density measured under the adatom redox peak, specific for the type of surface site, and the corresponding terrace size. The evaluation of the (100) bidimensional domains can also be achieved using the voltammetric profiles, once the fraction of (111) ordered domains present in the polyoriented platinum has been determined and their featureless contribution has been subtracted from the whole voltammetric response. Using that curve, it is possible to perform a deconvolution of the adsorption states of the polycrystalline sample different from those related to (111) domains. The fraction of (100)-related states in the deconvoluted voltammogram can then be compared to that expected from the independent estimation coming from the charge involved in the redox process undergone by the irreversibly-adsorbed germanium and thus check the result of the deconvolution. The information about the surface-site distribution can also be applied to analyze the voltammetric profile of nanocrystalline platinum electrodes.

  4. Uncertainty analysis of thermocouple measurements used in normal and abnormal thermal environment experiments at Sandia's Radiant Heat Facility and Lurance Canyon Burn Site.

    Energy Technology Data Exchange (ETDEWEB)

    Nakos, James Thomas

    2004-04-01

    It would not be possible to confidently qualify weapon systems performance or validate computer codes without knowing the uncertainty of the experimental data used. This report provides uncertainty estimates associated with thermocouple data for temperature measurements from two of Sandia's large-scale thermal facilities. These two facilities (the Radiant Heat Facility (RHF) and the Lurance Canyon Burn Site (LCBS)) routinely gather data from normal and abnormal thermal environment experiments. They are managed by Fire Science & Technology Department 09132. Uncertainty analyses were performed for several thermocouple (TC) data acquisition systems (DASs) used at the RHF and LCBS. These analyses apply to Type K, chromel-alumel thermocouples of various types: fiberglass sheathed TC wire, mineral-insulated, metal-sheathed (MIMS) TC assemblies, and are easily extended to other TC materials (e.g., copper-constantan). Several DASs were analyzed: (1) A Hewlett-Packard (HP) 3852A system, and (2) several National Instrument (NI) systems. The uncertainty analyses were performed on the entire system from the TC to the DAS output file. Uncertainty sources include TC mounting errors, ANSI standard calibration uncertainty for Type K TC wire, potential errors due to temperature gradients inside connectors, extension wire uncertainty, DAS hardware uncertainties including noise, common mode rejection ratio, digital voltmeter accuracy, mV to temperature conversion, analog to digital conversion, and other possible sources. Typical results for 'normal' environments (e.g., maximum of 300-400 K) showed the total uncertainty to be about {+-}1% of the reading in absolute temperature. In high temperature or high heat flux ('abnormal') thermal environments, total uncertainties range up to {+-}2-3% of the reading (maximum of 1300 K). The higher uncertainties in abnormal thermal environments are caused by increased errors due to the effects of imperfect TC attachment to

  5. Platinum catalysts recovery of the proton exchange membrane fuel cell; Recuperacao de catalisadores de platina da celula a combustibel de membrana polimerica trocadora de protons

    Energy Technology Data Exchange (ETDEWEB)

    Fukurozaki, S.H.; Seo, E.S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de Processamento de Residuos

    2006-07-01

    Currently, platinum is the most feasible catalyst for the Proton Exchange Membrane Fuel Cells - PEMFC. Along with platinum's significant importance in this energy system are the high cost of this noble metal and its detrimental effects on the environment. Therefore, recycling this material seems as an alternative to decrease its impacts on the environment and, at the same time, to provide a reduction of the system's costs. A search was conducted for literature and studies about platinum recycling methods. However, only two techniques of platinum recovery, which are still in development, were found. In face of this situation, a recovery method of platinum from deactivated Membrane Electrode Assembly - MEA's was developed, with attention to aspects related to the environment and the necessary requirements for its primary recycling. The results found showed a high recovery ratio and a possibility to reintroduce this metal into the production cycle. (author)

  6. Characterization of TiO[sub 2] films modified by platinum doping

    Energy Technology Data Exchange (ETDEWEB)

    Avalle, L.; Santos, E.; Leiva, E.; Macagno, V.A. (Dept. de Fisicoquimica, Univ. Nacional de Cordoba, INFIQC (Argentina))

    1992-10-30

    TiO[sub 2]-Pt films were prepared through galvanostatic platinum deposition from acidic H[sub 2]PtCl[sub 6] solutions, followed by potentiodynamic TiO[sub 2] growth in Na[sub 2]SO[sub 4] solutions. The characterization of the doped films was carried out by means of Auger electron spectroscopy and X-ray photoelectron spectroscopy (XPS) in combination with argon bombardment. The dopant concentration profiles and the valence states of the elements present within the films were also determined. The predominant species present is metallic platinum, although oxidized species probably make some contributions. Titanium changed from TiO[sub 2] to lower oxidation states in going from the surface to the film depth. XPS indicates the presence of hydrated oxides at the surface. Scanning electron microscopy (SEM) analyses indicate that platinum deposition occurs preferentially on grain boundaries. At high platinum content, clusters are evident and the substructure of titanium substrate is reproduced. At low platinum content, SEM cannot detect its presence at the surface in spite of the electrochemical evidence. The electrochemical behaviour of modified oxide films was also analysed. The potentiodynamic response correlates with the response of a polycrystalline platinum electrode. Electron transfer reactions reveal a catalytic effect due to the platinum incorporated into the TiO[sub 2] layer. The oxygen evolution reaction was investigated using impedance as a function of both the platinum content and the thickness of the TiO[sub 2] layer. Finally, an approximate physical model for the system is proposed.

  7. Influence of Dose on Particle Size and Optical Properties of Colloidal Platinum Nanoparticles

    Directory of Open Access Journals (Sweden)

    Elias Saion

    2012-11-01

    Full Text Available Attempts to produce colloidal platinum nanoparticles by using steady absorption spectra with various chemical-based reduction methods often resulted in the fast disappearance of the absorption maxima leaving reduced platinum nanoparticles with little information on their optical properties. We synthesized colloidal platinum nanoparticles in an aqueous solution of polyvinyl pyrrolidone by gamma radiolytic reduction method, which produced steady absorption spectra of fully reduced and highly pure platinum nanoparticles free from by-product impurities or reducing agent contamination. The average particle size was found to be in the range of 3.4–5.3 nm and decreased with increasing dose due to the domination of nucleation over ion association in the formation of metal nanoparticles by the gamma radiolytic reduction method. The platinum nanoparticles exhibit optical absorption spectra with two absorption peaks centered at about 216 and 264 nm and the peaks blue shifted to lower wavelengths with decreasing particle size. The absorption spectra of platinum nanoparticles were also calculated using quantum mechanical treatment and coincidently a good agreement was obtained between the calculated and measured absorption peaks at various particle sizes. This indicates that the 216 and 264-nm absorption peaks of platinum nanoparticles conceivably originated from the intra-band transitions of conduction electrons of (n = 5, l = 2 and (n = 6, l = 0 energy states respectively to higher energy states. The absorption energies, i.e., conduction band energies of platinum nanoparticles derived from the absorption peaks increased with increasing dose and decreased with increasing particle size.

  8. Phosphoric acid fuel cell platinum use study

    Science.gov (United States)

    Lundblad, H. L.

    1983-01-01

    The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

  9. K型热电偶检定过程中的测量不确定度评定%Measurement Uncertainty Evaluation of K-type Thermocouple in Verification

    Institute of Scientific and Technical Information of China (English)

    张洪俊; 陈红

    2012-01-01

    依据JJG351-1996《工作用廉金属热电偶检定规程》对某K型(镍铬-镍硅)热电偶进行了检定,在测量热电动势的基础上,系统分析了该法测量及换算温度误差的不确定度来源,并对热电偶温度误差的测量不确定度进行了评定和总结。%A K type (Cr-Ni and Ni) thermocouple was verified according to JJG 351 1996 “Verification Regulalion of Working Base Metal Thermocouple”. On the basis of measuring themal electromotive force, the sources of the uncertainty in measurement were analyzed systematically, and uncertainty in thermocouple' s verification of temperature error was assessed and summarized.

  10. 火焰原子吸收光谱法测定尾气净化金属载体催化剂中铂钯铑%Determination of platinum, palladium, rhodium in metal carrier catalyst for exhaust gas purification by flame atomic absorption spectrometry

    Institute of Scientific and Technical Information of China (English)

    施意华; 王晟; 杨仲平; 靳晓珠; 胡圣虹; 邓水平

    2012-01-01

    建立了火焰原子吸收光谱法测定尾气净化金属载体催化剂中Pt、Pd、Rh含量的新方法.研究了试样分解方法、共沉淀条件、测定干扰因素及消除方法.采用盐酸-超声波处理尾气净化金属载体催化剂,过滤,不溶物用过氧化钠分解,盐酸酸化后全部转化为样品溶液.在含2~3 mol/L盐酸的样品溶液.中,加入10 mg氧化碲和10 mL 200 g/L氯化亚锡溶液共沉淀富集样品溶液中的Pt、Pd、Rh,与基体元素Fe、Ni、Al、Cr、Na等完全分离,共沉淀物用王水溶解后,采用火焰原子吸收光谱法测定Pt、Pd、Rh.方法的检出限分别为:Pt 4.72 μg/g,Pd1.13μg/g,Rh 1.06 μg/g.将本方法用于实际样品分析,结果与电感耦合等离子体原子发射光谱法测定值一致,相对标准偏差(RSD,n=11)分别为:3.0%(Pt),1.9%(Pd),4.2%(Rh).%A novel method for the determination of platinum, palladium and rhodium in metal carrier catalyst for exhaust gas purification was established by flame atomic absorption spectrometrometry (FAAS). The sample decomposition method) coprecipitation condition, interference factor and elimination method were studied. The metal carrier catalyst sample for exhaust gas purification was treated by hydrochloric acid-ultrasonic wave, and filtrated. The insoluble substance was decomposed with sodium peroxide and acidized with hydrochloric acid, and then it was mixed with sample solution. 10 mg of tellurium oxide and 10 mL of 200 g/L SnCl2 solution were added to sample solution in the medium of 2-3 mol/L hydrochloric acid for the coprecipitation, enrichment and separation of palladium, platinum and rhodium from matrix elements such as Fe, Ni, Al, Cr and Na. After the coprecipitate was dissolved with aqua regia, the content of palladium, platinum and rhodium was determined by flame a-tomic absorption spectrometry. The detection limits of method for Pt, Pd and Rh are 4. 72,1.13 and 1. 06,respectively. The proposed method was applied to

  11. Cell integrated multi-junction thermocouple array for solid oxide fuel cell temperature sensing: N+1 architecture

    Science.gov (United States)

    Ranaweera, Manoj; Kim, Jung-Sik

    2016-05-01

    Understanding the cell temperature distribution of solid oxide fuel cell (SOFC) stacks during normal operation has multifaceted advantages in performance and degradation studies. Present efforts on measuring temperature from operating SOFCs measure only the gas channel temperature and do not reveal the cell level temperature distribution, which is more important for understanding a cell's performance and its temperature-related degradation. The authors propose a cell-integrated, multi-junction thermocouple array for in-situ cell surface temperature monitoring of an operational SOFC. The proposed thermocouple array requires far fewer numbers of thermoelements than that required by sets of thermocouples for the same number of temperature sensing points. Hence, the proposed array causes lower disturbance to cell performance than thermocouples. The thermoelement array was sputter deposited on the cathode of a commercial SOFC using alumel (Ni:Al:Mn:Si - 95:2:2:1 by wt.) and chromel (Ni:Cr - 90:10 by wt.). The thermocouple array was tested in a furnace over the entire operating temperature range of a typical SOFC. The individual sensing points of the array were shown to measure temperature independently from each other with equivalent accuracy to a thermocouple. Thus, the concept of multi-junction thermocouples is experimentally validated and its stability on a porous SOFC cathode is confirmed.

  12. Optoelectronic method for determining platinum in biological products

    Science.gov (United States)

    Radu, Simona; Ionicǎ, Mihai; Macovei, Radu Alexandru; Caragea, Genica; Forje, Mǎrgǎrita; Grecu, Iulia; Vlǎdescu, Marian; Viscol, Oana

    2016-12-01

    Of all platinum metals, platinum has the most uses and it's the most abundant and most easily to be processed. Its use in auto catalysts results in environmental contamination of crowded cities and high-traffic roads. In medicine, Pt is used as a cytostatic drug. In order to study the degree of contamination of the population with Pt or the correctness of treatment with Pt, it has been developed a method for its determination from urine or blood samples with a system Graphite Furnance - Atomic Absorption Spectrometer, (GF-AAS) Varian. There are presented the methods of sampling processing for blood or urine that followed the digest of the organic matrix. In the determination of the operating parameters for the system GF-AAS, was aimed the reducing of the nonanatomic absorbance by optimizing the drying temperatures, the calcination and atomization temperatures and the removal of the nonanatomic absorbance with D2 lamp. As a result of the use of the method are presented the concentrations of Pt in the blood or urine of a group of patients in Bucharest, a city with heavy traffic of vehicles. GF-AAS method presented is sensitive, reproducible, and relatively easy to apply with an acceptable cost. With this method, the concentration of Pt can be determined from blood and urine, both in order to establish the degree of contamination with Pt and for monitoring cancer therapy with platinum compounds.

  13. In vitro permeation of platinum through African and Caucasian skin.

    Science.gov (United States)

    Franken, A; Eloff, F C; du Plessis, J; Badenhorst, C J; Du Plessis, J L

    2015-02-03

    The majority of the South African workforce are Africans, therefore potential racial differences should be considered in risk and exposure assessments in the workplace. Literature suggests African skin to be a superior barrier against permeation and irritants. Previous in vitro studies on metals only included skin from Caucasian donors, whereas this study compared the permeation of platinum through African and Caucasian skin. A donor solution of 0.3 mg/ml of potassium tetrachloroplatinate (K₂PtCl₄) dissolved in synthetic sweat was applied to the vertical Franz diffusion cells with full thickness abdominal skin. Skin from three female African and three female Caucasian donors were included (n=21). The receptor solution was removed at various intervals during the 24 h experiment, and analysed with high resolution inductively coupled plasma-mass spectrometry (ICP-MS). Skin was digested and analysed by inductively coupled plasma-optical emission spectrometry (ICP-OES). Significantly higher permeation of platinum through intact African skin (p=0.044), as well as a significantly higher mass of platinum retention in African skin in comparison with Caucasian skin (p=0.002) occurred. Significant inter-donor variation was found in both racial groups (pplatinum salts. These results are contradictory to limited literature suggesting a superior barrier in African skin and further investigation is necessary to explain the higher permeation through African skin.

  14. The role of support and promoter on the oxidation of sulfur dioxide using platinum based catalysts

    DEFF Research Database (Denmark)

    Koutsopoulos, Sotiris; Rasmussen, Søren Birk; Eriksen, Kim Michael

    2006-01-01

    The catalytic oxidation of SO2 to SO3 was studied over platinum based catalysts in the absence and the presence of dopants. The active metal was supported on silica gel or titania (anatase) by impregnation. The activities of the silica supported catalysts were found to follow the order PtRh/SiO2...

  15. Ostwald Ripening of Platinum Nanoparticles Confined in a Carbon Nanotube/Silica-Templated Cylindrical Space

    Directory of Open Access Journals (Sweden)

    Cintia Mateo-Mateo

    2012-01-01

    Full Text Available Sintering of nanoparticles mediated by an Ostwald ripening mechanism is generally assessed examining the final particle size distributions. Based on this methodology, a general approach for depositing platinum nanoparticles onto carbon nanotubes in solution has been employed in order to evaluate the sintering process of these metallic nanoparticles at increasing temperatures in a carbon nanotube/silica-templated confined space.

  16. Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

    DEFF Research Database (Denmark)

    Stephens, Ifan E. L.; Bondarenko, Alexander S.; Grønbjerg, Ulrik;

    2012-01-01

    by alloying it with other metals. In this perspective paper we provide an overview of the fundamentals underlying the reduction of oxygen on platinum and its alloys. We also report the ORR activity of Pt5La for the first time, which shows a 3.5- to 4.5-fold improvement in activity over Pt in the range 0...

  17. Merensky pillar strength formulae based on back-analysis of pillar failures at Impala Platinum

    CSIR Research Space (South Africa)

    Watson, BP

    2008-08-01

    Full Text Available The Bushveld platinum group metal deposits are two distinct, shallow-dipping stratiform tabular orebodies and strike for many hundreds of kilometres. Mining is extensive, with depths ranging from close-to-surface to 2 000 m. The mining method is a...

  18. Investigation of morphological changes in platinum-containing nanostructures created by electron-beam-induced deposition

    NARCIS (Netherlands)

    Botman, A.; Hesselberth, M.; Mulders, J.J.L.

    2008-01-01

    Focused electron-beam-induced deposition (EBID) allows the rapid fabrication of three-dimensional nanodevices and metallic wiring of nanostructures, and is a promising technique for many applications in nanoresearch. The authors present two topics on platinum-containing nanostructures created by EBI

  19. Synthesis and ion-binding studies of platinum(Ⅱ) phenanthroline complexes containing crown ether moiety

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Two new benzo-[15]-crown-5 attached phenanthroline platinum(Ⅱ) complexes with the general formula Pt(phen)X2, where X = Cl (1), C≡CC6H5 (2) have been synthesized, and their absorption and luminescence response towards metal ions have been studied.

  20. Development of the thermocouple spot welder%热电偶点焊机的研制

    Institute of Scientific and Technical Information of China (English)

    王立冬; 周旭东

    2011-01-01

    热电偶是一种常用的测温元件,而传统的热电偶在焊接时由于本身裸露在空气中,试样与热电偶之间的焊点及临近区域难免被氧化,这样不仅降低了焊点的牢固性而且对测温的准确性也有一定的影响.为解决上述问题,设计和研制了焊接热电偶的专用设备--热电偶点焊机,该设备除了采用传统的储能式点焊机的基本原理外,在焊接时还采用了氩气保护,有效的解决了上述问题.并且对直径为0.2 mm镍铬-镍铝热电偶(K型热电偶)进行了焊接实验测试,通过在显微镜下观察焊点及附近区域的焊接效果结果表明,用本设备焊接的热电偶焊接效果良好而且有效地降低了焊点及附近区域的氧化现象.%Thermocouple is a kind of common temperature-measuring elements. However,While the traditional thermocouple being weld,due to bating the thermocouple itself in the air,there is no way to avoid the oxidation between sample and the thermocouple and the surrounding area. Thereby it not only reduce the soundness of welding spot,but also affects the accaracy of temperature measurement.In order to solve the mentioned problem,we have designed and manufactured a spot welding machine-Thermocouple Spot Welding,which specialize in weldimg the thermocouple.In addition to using the basic principle of traditional energy storage type spot welding machine,the protection of Ar is apphed,and it solve the mentioned problem effectively. By doing the welding test on the 0.2 mm in diameter nickel-based thermocouple(K-type), viewing welding spot under a microscope, the results show that oxidation phenomenon has been reduced effectively and the the effect of welding is so good with using this machine.

  1. Long term out-of-pile thermocouple tests in conditions representative for nuclear gas-cooled high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Laurie, M., E-mail: mathias.laurie@ec.europa.eu [European Commission, Joint Research Centre, Institut für Transurane, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen (Germany); Fourrez, S. [THERMOCOAX SAS, Rue du Pré Neuf, 61100 Saint Georges des Groseillers (France); Fütterer, M.A.; Lapetite, J.M. [European Commission, Joint Research Centre, Institut für Transurane, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen (Germany); Sadli, M.; Morice, R.; Failleau, G. [Laboratoire commun de métrologie LNE-Cnam, 61 rue du Landy, F-92310 Saint-Denis (France)

    2014-05-01

    During irradiation tests at high temperature failure of commercial Inconel 600 sheathed thermocouples is commonly encountered. As instrumentation, in particular thermocouples are considered safety-relevant both for irradiation tests and for commercial reactors, JRC and THERMOCOAX joined forces to solve this issue by performing out-of-pile tests with thermocouples mimicking the environment encountered by high temperature reactor (HTR) in-core instrumentation. The objective was to screen innovative sheathed thermocouples which would consecutively be tested under irradiation. Two such screening tests have been performed in high temperature environment (i.e. temperature in the range 1100–1150 °C) with purposely contaminated helium atmosphere (mainly CH{sub 4}, CO, CO{sub 2}, O{sub 2} impurities) representative for high temperature reactor carburizing atmospheres. The first set of thermocouples embedded in graphite (mainly conventional N type thermocouples and thermocouples with innovative sheaths) was tested in a dedicated furnace at THERMOCOAX lab with helium flushing. The second out-of-pile test at JRC with a partly different set of thermocouples replicated the original test for comparison. Performance indicators such as thermal drift, insulation resistance and loop resistance were monitored. Through these long-term screening tests the effect of several parameters were investigated: niobium sleeves, bending, diameter, sheath composition as well as the chemical environment. SEM examinations were performed to analyze local damage (bending zone, sheath). The present paper describes the two tests, sums up data collected during these tests in terms of thermocouple behavior and describes further instrumentation testing work with fixed point mini cells for qualification under irradiation.

  2. Simple cerium-triethanolamine complex: Synthesis, characterization, thermal decomposition and its application to prepare ceria support for platinum catalysts used in methane steam reforming

    Science.gov (United States)

    Wattanathana, Worawat; Nootsuwan, Nollapan; Veranitisagul, Chatchai; Koonsaeng, Nattamon; Laosiripojana, Navadol; Laobuthee, Apirat

    2015-06-01

    Cerium-triethanolamine complex was synthesized by simple complexation method in 1-propanol solvent using cerium(III) chloride as a metal source and triethanolamine as a ligand. The structures of the prepared complex were proposed based on FT-IR, FT-Raman and ESI-MS results as equimolar of triethanolamine and cerium chelated complex having monomeric tricyclic structure with and without chloride anion as another coordinating group known as ceratrane. The complex was used as a precursor for ceria material done by thermal decomposition. XRD result revealed that when calcined at 600 °C for 2 h, the cerium complex was totally turned into pure ceria with cubic fluorite structure. The obtained ceria was then employed to synthesize platinum doped ceria catalysts for methane steam reforming. Various amounts of platinum i.e. 1, 3, 5 and 10 mol percents were introduced on the ceria support by microwave-assisted wetness impregnation using ammonium tetrachloroplatinate(II). The platinum-impregnated ceria powders were subjected to calcination in 10% hydrogen/helium atmosphere at 500 °C for 3 h to reduce platinum(II) to platinum(0). XRD patterns of the catalysts confirmed that the platinum particles doped on the ceria support were in the form of platinum(0). Catalytic activity test showed that the catalytic activities got higher as the amounts of platinum doped increased. Besides, the portions of coke formation on the surface of catalysts were reduced as the amounts of platinum doped increased.

  3. Method for collecting thermocouple data via secured shell over a wireless local area network in real time.

    Science.gov (United States)

    Arnold, F; DeMallie, I; Florence, L; Kashinski, D O

    2015-03-01

    This manuscript addresses the design, hardware details, construction, and programming of an apparatus allowing an experimenter to monitor and record high-temperature thermocouple measurements of dynamic systems in real time. The apparatus uses wireless network technology to bridge the gap between a dynamic (moving) sample frame and the static laboratory frame. Our design is a custom solution applied to samples that rotate through large angular displacements where hard-wired and typical slip-ring solutions are not practical because of noise considerations. The apparatus consists of a Raspberry PI mini-Linux computer, an Arduino micro-controller, an Ocean Controls thermocouple multiplexer shield, and k-type thermocouples.

  4. Method for collecting thermocouple data via secured shell over a wireless local area network in real time

    Science.gov (United States)

    Arnold, F.; DeMallie, I.; Florence, L.; Kashinski, D. O.

    2015-03-01

    This manuscript addresses the design, hardware details, construction, and programming of an apparatus allowing an experimenter to monitor and record high-temperature thermocouple measurements of dynamic systems in real time. The apparatus uses wireless network technology to bridge the gap between a dynamic (moving) sample frame and the static laboratory frame. Our design is a custom solution applied to samples that rotate through large angular displacements where hard-wired and typical slip-ring solutions are not practical because of noise considerations. The apparatus consists of a Raspberry PI mini-Linux computer, an Arduino micro-controller, an Ocean Controls thermocouple multiplexer shield, and k-type thermocouples.

  5. Platinum(II) complexes as spectroscopic probes for biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ratilla, E.

    1990-09-21

    The use of platinum(II) complexes as tags and probes for biomolecules is indeed advantageous for their reactivities can be selective for certain purposes through an interplay of mild reaction conditions and of the ligands bound to the platinum. The use of {sup 195}Pt NMR as a method of detecting platinum and its interactions with biomolecules was carried out with the simplest model of platinum(II) tagging to proteins. Variable-temperature {sup 195}Pt NMR spectroscopy proved useful in studying the stereodynamics of complex thioethers like methionine. The complex, Pt(trpy)Cl{sup +}, with its chromophore has a greater potential for probing proteins. It is a noninvasive and selective tag for histidine and cysteine residues on the surface of cytochrome c at pH 5. The protein derivatives obtained are separable, and the tags are easily quantitated and differentiated through the metal-to-ligand charge transfer bands which are sensitive to the environment of the tag. Increasing the pH to 7.0 led to the modification by Pt(trpy)Cl{sup +}of Arg 91 in cytochrome c. Further studies with guanidine-containing ligands as models for arginine modification by Pt(trpy)Cl{sup +} showed that guanidine can act as a terminal ligand and as a bridging ligand. Owing to the potential utility of Pt(trpy)L{sup n+} as electron dense probes of nucleic acid structure, interactions of this bis-Pt(trpy){sup 2+} complex with nucleic acids was evaluated. Indeed, the complex interacts non-covalently with nucleic acids. Its interactions with DNA are not exactly the same as those of its precedents. Most striking is its ability to form highly immobile bands of DNA upon gel electrophoresis. 232 refs.

  6. 16 CFR 23.7 - Misuse of the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium,” and “osmium.”

    Science.gov (United States)

    2010-01-01

    ... § 23.7 Misuse of the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium,” and “osmium.” (a) It is unfair or deceptive to use the words “platinum,” “iridium,” “palladium,” “ruthenium,” “rhodium... marking or description misrepresents the product's true composition. The Platinum Group Metals (PGM)...

  7. Hall measurements on carbon nanotube paper modified with electroless deposited platinum.

    Science.gov (United States)

    Petrik, Leslie; Ndungu, Patrick; Iwuoha, Emmanuel

    2009-09-18

    Carbon nanotube paper, sometimes referred to as bucky paper, is a random arrangement of carbon nanotubes meshed into a single robust structure, which can be manipulated with relative ease. Multi-walled carbon nanotubes were used to make the nanotube paper, and were subsequently modified with platinum using an electroless deposition method based on substrate enhanced electroless deposition. This involves the use of a sacrificial metal substrate that undergoes electro-dissolution while the platinum metal deposits out of solution onto the nanotube paper via a galvanic displacement reaction. The samples were characterized using SEM/EDS, and Hall-effect measurements. The SEM/EDS analysis clearly revealed deposits of platinum (Pt) distributed over the nanotube paper surface, and the qualitative elemental analysis revealed co-deposition of other elements from the metal substrates used. When stainless steel was used as sacrificial metal a large degree of Pt contamination with various other metals was observed. Whereas when pure sacrificial metals were used bimetallic Pt clusters resulted. The co-deposition of a bimetallic system upon carbon nanotubes was a function of the metal type and the time of exposure. Hall-effect measurements revealed some interesting fluctuations in sheet carrier density and the dominant carrier switched from N- to P-type when Pt was deposited onto the nanotube paper. Perspectives on the use of the nanotube paper as a replacement to traditional carbon cloth in water electrolysis systems are also discussed.

  8. Hall Measurements on Carbon Nanotube Paper Modified With Electroless Deposited Platinum

    Directory of Open Access Journals (Sweden)

    Iwuoha Emmanuel

    2009-01-01

    Full Text Available Abstract Carbon nanotube paper, sometimes referred to as bucky paper, is a random arrangement of carbon nanotubes meshed into a single robust structure, which can be manipulated with relative ease. Multi-walled carbon nanotubes were used to make the nanotube paper, and were subsequently modified with platinum using an electroless deposition method based on substrate enhanced electroless deposition. This involves the use of a sacrificial metal substrate that undergoes electro-dissolution while the platinum metal deposits out of solution onto the nanotube paper via a galvanic displacement reaction. The samples were characterized using SEM/EDS, and Hall-effect measurements. The SEM/EDS analysis clearly revealed deposits of platinum (Pt distributed over the nanotube paper surface, and the qualitative elemental analysis revealed co-deposition of other elements from the metal substrates used. When stainless steel was used as sacrificial metal a large degree of Pt contamination with various other metals was observed. Whereas when pure sacrificial metals were used bimetallic Pt clusters resulted. The co-deposition of a bimetallic system upon carbon nanotubes was a function of the metal type and the time of exposure. Hall-effect measurements revealed some interesting fluctuations in sheet carrier density and the dominant carrier switched from N- to P-type when Pt was deposited onto the nanotube paper. Perspectives on the use of the nanotube paper as a replacement to traditional carbon cloth in water electrolysis systems are also discussed.

  9. Platinum nanoparticles: a promising material for future cancer therapy?

    Science.gov (United States)

    Porcel, Erika; Liehn, Samuel; Remita, Hynd; Usami, Noriko; Kobayashi, Katsumi; Furusawa, Yoshiya; Le Sech, Claude; Lacombe, Sandrine

    2010-02-26

    Recently, the use of gold nanoparticles as potential tumor selective radiosensitizers has been proposed as a breakthrough in radiotherapy. Experiments in living cells and in vivo have demonstrated the efficiency of the metal nanoparticles when combined with low energy x-ray radiations (below conventional 1 MeV Linac radiation). Further studies on DNA have been performed in order to better understand the fundamental processes of sensitization and to further improve the method. In this work, we propose a new strategy based on the combination of platinum nanoparticles with irradiation by fast ions effectively used in hadron therapy. It is observed in particular that nanoparticles enhance strongly lethal damage in DNA, with an efficiency factor close to 2 for double strand breaks. In order to disentangle the effect of the nano-design architecture, a comparison with the effects of dispersed metal atoms at the same concentration has been performed. It is thus shown that the sensitization in nanoparticles is enhanced due to auto-amplified electronic cascades inside the nanoparticles, which reinforces the energy deposition in the close vicinity of the metal. Finally, the combination of fast ion radiation (hadron therapy) with platinum nanoparticles should strongly improve cancer therapy protocols.

  10. Novel compliant electrodes based on platinum salt reduction

    Science.gov (United States)

    Delille, Remi; Urdaneta, Mario; Hsieh, Kuangwen; Smela, Elisabeth

    2006-03-01

    A compliant electrode material is presented that was inspired by the electroding process used to manufacture ionic polymer-metal composites (IPMCs). However, instead of an ion-exchange membrane, a UV-curable acrylated urethane elastomer is employed. The electrode material consists of the UV-curable elastomer (Loctite 3108) loaded with tetraammineplatinum(II) chloride salt particles through physical mixing and homogenization. The composite material is made conductive by immersion in a reducing agent, sodium borohydride, which reduces the salt to platinum metal on the surface of the elastomer film. Because the noble metal is mixed into the elastomer precursor as a salt, the amount of UV light absorbed by the precursor is not significantly reduced, and the composite loses little photopatternability. As a result meso-scale electrodes of varying geometries can be formed by exposing the precursor/salt mixture through a mask. The materials are mechanically and electrically characterized. The percolation threshold of the composite is estimated to be 9 vol. % platinum salt, above which the compliant electrode material exhibits a maximum conductivity of 1 S/cm. The composite maintains its electrical conductivity under axial tensile strains of up to 40%.

  11. Green Synthesis, Characterization and Uses of Palladium/Platinum Nanoparticles

    Science.gov (United States)

    Siddiqi, Khwaja Salahuddin; Husen, Azamal

    2016-11-01

    Biogenic synthesis of palladium (Pd) and platinum (Pt) nanoparticles from plants and microbes has captured the attention of many researchers because it is economical, sustainable and eco-friendly. Plant and their parts are known to have various kinds of primary and secondary metabolites which reduce the metal salts to metal nanoparticles. Shape, size and stability of Pd and Pt nanoparticles are influenced by pH, temperature, incubation time and concentrations of plant extract and that of the metal salt. Pd and Pt nanoparticles are broadly used as catalyst, as drug, drug carrier and in cancer treatment. They have shown size- and shape-dependent specific and selective therapeutic properties. In this review, we have discussed the biogenic fabrication of Pd/Pt nanoparticles, their potential application as catalyst, medicine, biosensor, medical diagnostic and pharmaceuticals.

  12. [Platinum compounds: metabolism, toxicity and supportive strategies].

    Science.gov (United States)

    Lipp, H P; Hartmann, J T

    2005-02-09

    Although the leading platinum compounds, cisplatin, carboplatin, and oxaliplatin, share some structural similarities, there are marked differences between them in therapeutic uses, pharmacokinetics, and adverse effects profiles. Compared with cisplatin, carboplatin has inferior efficacy in germ-cell tumors, head and neck cancers, and bladder and esophageal carcinomas, whereas the two drugs appear to have comparable efficacy in ovarian cancer, extensive small-cell lung cancers (SCLC), and advanced non-small-cell lung cancers (NSCLC). Oxaliplatin belongs to the group of diaminocyclohexane (DACH) platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid. Nedaplatin has been registered in Japan, whereas other derivatives, like JM216 (which is the only orally available platinum derivative), ZD0473, BBR3464, and SPI-77 (a liposomal formulation of cisplatin), are still under investigation. The adverse effects of platinum compounds are reviewed together with possible prevention strategies.

  13. Measurement System of Reducing Temperature Fluctuation of Thermostat Bath for Calibrating Thermocouple

    OpenAIRE

    Zhang, Min; Liang, Feixia; Xie, Yue; Huang, Ruguo; Yuan, Haitao; Lu, Jiahua

    2014-01-01

    International audience; Based on the periodic unsteady state heat conduction theory, a new measurement system of reducing temperature fluctuation of thermostat bath was developed in order to obtain a liquid environment with uniform and constant temperature controlled for the measurement requirements of calibrating thermocouple. The experimental results show that the temperature stability in this measurement system is superior to that in traditional system. The measurement system had the advan...

  14. Platinum Interference with siRNA Non-seed Regions Fine-Tunes Silencing Capacity

    DEFF Research Database (Denmark)

    Hedman, Hanna K; Kirpekar, Finn; Elmroth, Sofi K C

    2011-01-01

    , cisplatin and oxaliplatin, on siRNA's silencing capacity has been evaluated. More specifically, siRNAs targeting the 3' UTR region of Wnt-5a mRNA (NM_003352) were constructed, and the biologically active antisense RNA strand was pre-platinated. Platinum adducts were detected and characterized...... of the platination sites, i.e., with altered degradation patterns compared to native RNAs. The MALDI-MS method was successfully used to further identify and characterize platinated RNA, with the naturally occurring platinum isotopic patterns serving as sensitive fingerprints for metalated sites. Expression assays...

  15. SYNTHESIS AND CATALYTIC BEHAVIOR OF POLYSILOXANE-SUPPORTED FULLERENE PLATINUM OR RHODIUM COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Fang; Yuan-yin Chen; Shu-ling Gong; Lei Guo; Qiu-sheng Lu; Ling Zhu

    1999-01-01

    Two polysiloxanes with pendant fullerene moieties and their platinum or rhodium complexes have been prepared from C60 via amination with ω-decenylamine, followed by hydrosilylation with triethoxysilane and immobilization on fumed silica or by hydrosilylation with methyldichlorosilane and polycondensation with polydimethylsiloxanol, and then by reacting them with potassium chloroplatinite or rhodium chloride in acetone respectively under argon atmosphere. It was found that the four noble metal complexes are effective catalysts for the hydrosilylation of olefins with triethoxysilane. The regioselectivity of platinum complexes for styrene increases remarkably by introducing C60 moiety. Factors influencing catalytic activity and the mechanism have been investigated.

  16. Nanolithographic Fabrication and Heterogeneous Reaction Studies ofTwo-Dimensional Platinum Model Catalyst Systems

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Anthony Marshall [Univ. of California, Berkeley, CA (United States)

    2006-05-20

    In order to better understand the fundamental components that govern catalytic activity, two-dimensional model platinum nanocatalyst arrays have been designed and fabricated. These catalysts arrays are meant to model the interplay of the metal and support important to industrial heterogeneous catalytic reactions. Photolithography and sub-lithographic techniques such as electron beam lithography, size reduction lithography and nanoimprint lithography have been employed to create these platinum nanoarrays. Both in-situ and ex-situ surface science techniques and catalytic reaction measurements were used to correlate the structural parameters of the system to catalytic activity.

  17. The Recovery of the Metal Insulation Cable in the Instrumentation of Nuclear Fuel Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang Young; Ahn, Sung Ho; Sim, Bong Sik; Lee, Chul Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-10-15

    Mineral-insulated (MI) cables are widely used to prolong the instrumentation cable of instruments such as a thermocouple (TC), linear variable differential transformer (LVDT) and self-powered neutron detector (SPND), which are used to measure various irradiation characteristics of nuclear fuels and materials. MI cables are expected to be helpful for instrumentation of nuclear fuel and material irradiation because of their high electrical insulation, heat resistance and mechanical strength. The MI cable used to extend thermocouple wires is classified as the following: 1) For common metal types of thermocouples, the thermocouple extension wire is of substantially the same composition as the corresponding thermocouple type and it can offer advantages in cost or mechanical properties when used for the connection between a thermocouple and instruments. 2) For noble metal types of thermocouples, the thermocouple compensation wire is an entirely different alloy formulated to match the noble metal characteristics, which is necessary due to the high cost of noble metals. During the installation of an instrument, an MI cable damaged by impact must be recovered because it is difficult to change the entire thermocouple. And for MI cable recovery, it is necessary to develop the instrumentation technology of FTL. This paper described the experimental results of MI cable recovery, which consists of a removal test of the MI cable sheath and a joining test of the compensation of the wire and MI cable/ wire/compensation wire and sheath of MI cable/bushing, for carrying out irradiation tests of nuclear fuel and materials in the FTL facility of HANARO

  18. Thermal power output determination of 2 MW heat source by using of thermocouples

    Science.gov (United States)

    Holubcik, Michal; Vician, Peter; Palacka, Matej

    2016-06-01

    Experiment is an operation or procedure carried out under controlled conditions in order to discover an unknown effect or law, to test or establish a hypothesis, or to illustrate a known law. The most important part of the experiment is to evaluate the measured values. Measurement accuracy depends on a number of factors. Deviations of instruments cannot eliminate or influence if it is neglect the possibility of using more precise measuring equipment. Another way for the most accurate results can be calibration. Calibration allows achieve measurement values with relatively high accuracy using less precision instruments. The paper deals about the problematic of thermal power measurement accuracy. Thermal power was measured on heat source with nominal thermal power 2 MW by using direct calorimetric method. There were used ultrasonic flow meter and type K thermocouples. Type K thermocouples are not very suitable for these applications because of their low precision. The paper presents the possibility of using calibrated thermocouples for the thermal power measurement with acceptable accuracy.

  19. Relating Composition and Thermoelectric Stability of Pt-Rh Alloy Thermocouples

    Science.gov (United States)

    Pearce, J. V.; Greenen, A. D.; Smith, A.; Elliott, C. J.

    2017-02-01

    A simple model is presented which relates the electromotive force drift rate of Pt-Rh thermoelements to dS/dc, the sensitivity of the Seebeck coefficient, S, to rhodium mass fraction, c. The model has been tested by repeated measurements of a Pt-Rh thermocouple assembly consisting of five thermoelements, using a Co-C high-temperature fixed point (1324°C) for a total duration of 500 h. By considering various thermocouples from the assembly, it is demonstrated that in this case, remarkably, there is a linear relationship between the measured drift rate and the combined dS/dc, where the combination is determined by addition of the individual values for each wire. Particular emphasis is placed on evaluation of the uncertainties associated with the calculations. This result supports previous findings that the thermoelectric stability of Pt-Rh thermoelements improves as the rhodium mass fraction increases. Within this paradigm, it is shown that for a selected Pt-Rh thermoelement of any given composition, there exists a second thermoelement having a composition that yields a minimum drift when combined with the first to form a thermocouple.

  20. Application of Thin-Film Thermocouples to Localized Heat Transfer Measurements

    Science.gov (United States)

    Lepicovsky, J.; Bruckner, R. J.; Smith, F. A.

    1995-01-01

    The paper describes a proof-of-concept experiment on thin-film thermocouples used for localized heat transfer measurements applicable to experiments on hot parts of turbine engines. The paper has three main parts. The first part describes the thin-film sensors and manufacturing procedures. Attention is paid to connections between thin-film thermocouples and lead wires, which has been a source of problems in the past. The second part addresses the test arrangement and facility used for the heat transfer measurements modeling the conditions for upcoming warm turbine tests at NASA LeRC. The paper stresses the advantages of a modular approach to the test rig design. Finally, we present the results of bulk and local heat flow rate measurements, as well as overall heat transfer coefficients obtained from measurements in a narrow passage with an aspect ratio of 11.8. The comparison of bulk and local heat flow rates confirms applicability of thin-film thermocouples to upcoming warm turbine tests.

  1. Biosorption of platinum and palladium for their separation/preconcentration prior to graphite furnace atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska-Zylkiewicz, Beata E-mail: bgodlew@uwb.edu.pl

    2003-08-15

    Inexpensive baker's yeast Saccharomyces cerevisiae and green algae Chlorella vulgaris, either free or immobilized on silica gel have been shown to selectively accumulate platinum and palladium from water samples in acidic medium (pH 1.6-1.8). Optimization of conditions of metals biosorption (sample pH, algae and yeast masses, adsorption time, temperature) was performed in batch mode. The procedure of matrix separation based on biosorption of platinum and palladium on algae C. vulgaris covalently immobilized on silica gel in flow mode was developed. The use of algae in flow procedure offers several advantages compared with its use in the batch mode. The procedure shows better reproducibility (<2%), improved efficiency of platinum retention on the column (93.3{+-}1.6%), is less laborious and less time consuming. The best recovery of biosorbed metals from column (87.7{+-}3.3% for platinum and 96.8{+-}1.1 for palladium) was obtained with solution of 0.3 mol l{sup -1} thiourea in 1 mol l{sup -1} hydrochloric acid. The influence of thiourea on analytical signals of examined metals during GFAAS determination is discussed. The procedure has been applied for separation of noble metals from tap and waste water samples spiked with platinum and palladium.

  2. Improved and selective platinum recovery from spent alpha-alumina supported catalysts using pretreated anionic ion exchange resin.

    Science.gov (United States)

    Shams, K; Goodarzi, F

    2006-04-17

    Improved and selective recovery of platinum from a spent dehydrogenation platinum alpha-alumina supported catalyst using a strong basic ion exchange resin is reported. Platinum and other precious metal group (PMG) complexes are leached using concentrated hydrochloric acid along with about 0.20 vol.% nitric acid as an oxidizing agent from de-coked and crushed spent catalyst. Effects of hydrochloric acid concentration, time, and temperature in leaching stage are investigated. The strong basic anionic resin is treated by sodium hydroxide solution to replace chloride anion by hydroxyl group ion. The supernatant of the leaching process is passed through a fixed column of hydroxylated strong base anionic resin. The treated resin on which the platinum complex is adsorbed is dried and burned in an oxidizing atmosphere at 750-800 degrees C. The recovered gray metallic powder is mainly platinum. Results compared with those obtained from untreated anionic resin show that adsorption of platinum complexes onto the treated anionic resin is more selective and the yield of separation is considerably improved. The breakthrough curves of the pretreated anion exchanger and that of untreated exchange resin reveals that the capacity of the hyroxilated resin is decreased by about 14%. These breakthrough curves can be used for calculation of height of a practical exchange plate (HPEP) for design purposes.

  3. Effect of platinum nanoparticle deposition parameters on hydrogen peroxide transduction for applications in wearable electrochemical glucose biosensors

    Science.gov (United States)

    Cargill, Allison A.; Neil, Kathrine M.; Hondred, John A.; McLamore, Eric S.; Claussen, Jonathan C.

    2016-05-01

    Enhanced interest in wearable biosensor technology over the past decade is directly related to the increasing prevalence of diabetes and the associated requirement of daily blood glucose monitoring. In this work we investigate the platinum-carbon transduction element used in traditional first-generation glucose biosensors which rely on the concentration of hydrogen peroxide produced by the glucose-glucose oxidase binding scheme. We electrodeposit platinum nanoparticles on a commercially-available screen printed carbon electrode by stepping an applied current between 0 and 7.12 mA/cm2 for a varying number of cycles. Next, we examine the trends in deposition and the effect that the number of deposition cycles has on the sensitivity of electrochemical glucose sensing. Results from this work indicate that applying platinum nanoparticles to screen printed carbon via electrodeposition from a metal salt solution improves overall biosensor sensitivity. This work also pinpoints the amount of platinum (i.e., number of deposition cycles) that maximizes biosensor sensitivity in an effort to minimize the use of the precious metals, viz., platinum, in electrode fabrication. In summary, this work quantifies the relationship between platinum electrodeposition and sensor performance, which is crucial in designing and producing cost-effective sensors.

  4. Platinum incorporation in the Na Y zeolite through impregnation method, and characterization by XRD, FTIR and nitrogen adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, A.S.; Sousa, B.V.; Andrade, A.C.C.; Rodrigues, M.G.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Centro de Ciencias e Tecnologia. Unidade Academica de Engenharia Quimica], e-mail: alfredinad@yahoo.com.br, e-mail: biancaviana_cg@yahoo.com.br, e-mail: meiry@deq.ufcg.edu.br; Rangel, M.C. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Estudos em Cinetica e Catalise

    2007-07-01

    Supported metal catalysts are widely used in petroleum refining, chemical and petroleum industries. These catalysts are important in ammonia synthesis, conversion of hydrocarbons with water vapor to synthesis gas, reforming, hydrocracking, ... Platinum has long been used in cracking, hydrogenation and dehydrogenation processes. The aim of this project is the Na Y zeolitic sample preparation through impregnation for incipient humidity, with 0,5% concentration of platinum, aiming its use as a catalyst in the steam reforming reaction. The characterization techniques used were: X Rays Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Nitrogen Adsorption (BET Method). From the obtained results through the techniques mentioned previously it is possible to evidence that the platinum impregnation process did not change the Na Y zeolite structure. Through the superficial specific area (BET) it was possible to observe that the platinum impregnation process caused a decrease in the specific area due to the reduction to the accessibility to the micropores of the zeolitic structure. (author)

  5. Precise tuning in platinum-nickel/nickel sulfide interface nanowires for synergistic hydrogen evolution catalysis

    Science.gov (United States)

    Wang, Pengtang; Zhang, Xu; Zhang, Jin; Wan, Sheng; Guo, Shaojun; Lu, Gang; Yao, Jianlin; Huang, Xiaoqing

    2017-01-01

    Comprising abundant interfaces, multicomponent heterostructures can integrate distinct building blocks into single entities and yield exceptional functionalities enabled by the synergistic components. Here we report an efficient approach to construct one-dimensional metal/sulfide heterostructures by directly sulfuring highly composition-segregated platinum-nickel nanowires. The heterostructures possess a high density of interfaces between platinum-nickel and nickel sulfide components, which cooperate synergistically towards alkaline hydrogen evolution reaction. The platinum-nickel/nickel sulfide heterostructures can deliver a current density of 37.2 mA cm−2 at an overpotential of 70 mV, which is 9.7 times higher than that of commercial Pt/C. The heterostructures also offer enhanced stability revealed by long-term chronopotentiometry measurements. The present work highlights a potentially powerful interface-engineering strategy for designing multicomponent heterostructures with advanced performance in hydrogen evolution reaction and beyond. PMID:28239145

  6. Thermally stable single-atom platinum-on-ceria catalysts via atom trapping

    Energy Technology Data Exchange (ETDEWEB)

    Jones, John; Xiong, Haifeng; DelaRiva, Andrew; Peterson, Eric J.; Pham, Hien; Challa, Sivakumar R.; Qi, Gongshin; Oh, Se H.; Wiebenga, Michelle H.; Pereira Hernandez, Xavier I.; Wang, Yong; Datye, Abhaya K.

    2016-07-08

    Catalysts based on single atoms of scarce precious metals can lead to more efficient use through enhanced reactivity and selectivity. However, single atoms on catalyst supports can be mobile and aggregate into nanoparticles when heated at elevated temperatures. High temperatures are detrimental to catalyst performance unless these mobile atoms can be trapped. We used ceria powders having similar surface areas but different exposed surface facets. When mixed with a platinum/ aluminum oxide catalyst and aged in air at 800°C, the platinum transferred to the ceria and was trapped. Polyhedral ceria and nanorods were more effective than ceria cubes at anchoring the platinum. Performing synthesis at high temperatures ensures that only the most stable binding sites are occupied, yielding a sinter-resistant, atomically dispersed catalyst.

  7. Extraction and separation studies of platinum(IV) with N-n-octylaniline.

    Science.gov (United States)

    Lokhande, T N; Anuse, M A; Chavan, M B

    1998-11-01

    N-n-octylaniline in xylene is used for the extractive separation of platinum(IV) from acidic media. Platinum(IV) was extracted quantitatively with 10 ml of 3% reagent in xylene from 0.5 to 10 and 2.5 to 10 M hydrochloric and sulphuric acid, respectively. It was stripped from organic phase with water and estimated photometrically with stannous chloride. The effect of metal ion, acids, reagent concentration and of various foreign ions has been investigated. The method affords binary separation of platinum(IV) from iron(III), cobalt(II), nickel(II) and copper(II), and is applicable to the analysis of synthetic mixtures and alloys. The method is fast, accurate and precise.

  8. New transition metal-rich rare-earth palladium/platinum aluminides with RET{sub 5}Al{sub 2} composition. Structure, magnetism and {sup 27}Al NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Benndorf, Christopher [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Stegemann, Frank; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie

    2015-06-01

    REPd{sub 5}Al{sub 2} compounds with RE = Ce-Gd as well as Y and Lu have been previously synthesized. Although some compounds with the small lanthanides also exist, the compounds with intermediate-sized rare-earth elements (RE = Tb-Yb) had not been prepared. We report on the missing members of the REPd{sub 5}Al{sub 2} (RE = Tb-Yb) series as well as on the new REPt{sub 5}Al{sub 2} (RE = Y, Gd-Tm, Lu) series, which we have synthesized and structurally as well as magnetically characterized. All members crystallize isostructurally in the ZrNi{sub 2}Al{sub 5} type with an anti-arrangement of the T = Pd/Pt and Al atoms. YPd{sub 5}Al{sub 2} and LuPd{sub 5}Al{sub 2}, as well as the respective platinum homologs, YPt{sub 5}Al{sub 2} and LuPt{sub 5}Al{sub 2}, have been characterized also by {sup 27}Al magic-angle spinning nuclear magnetic resonance spectroscopy. Consistent with the XRD analysis, the spectra indicate the existence of only one distinct Al site in the structure.

  9. Room temperature synthesis of colloidal platinum nanoparticles

    Indian Academy of Sciences (India)

    G Sarala Devi; V J Rao

    2000-12-01

    Efficient preparation of stable dispersions of platinum nanoparticles from platinous chloride (K2PtCl4) was achieved by simultaneous addition of capping polymer material. The size of platinum nanoparticles was controlled by changing the ratio of concentration of capping polymer material to the concentration of platinum cation used. The morphology of colloidal particles were studied by means of UV-visible spectrophotometry and transmission electron microscopy (TEM). Particle size increased with low reagent concentration. The change in absorption spectra with the particle size was observed, i.e. blue shift attributed to decrease in particle size.

  10. Stabilizing platinum in phosphoric acid fuel cells

    Science.gov (United States)

    Remick, R. J.

    1981-10-01

    A carbon substrate for use in fabricating phosphoric acid fuel cell cathodes was modified by catalytic oxidation to stabilize the platinum catalyst by retarding the sintering of small platinum crystallites. Results of 100-hour operational tests confirmed that the rate of platinum surface area loss observed on catalytically oxidized supports was less than that observed with unmodified supports of the same starting material. Fuel cell electrodes fabricated from Vulcan XC-72R, which was modified by catalytic in a nitric oxide atmosphere, produced low platium sintering rates and high activity for the reduction of oxygen in the phosphoric acid environment.

  11. Antitumor effect of arabinogalactan and platinum complex.

    Science.gov (United States)

    Starkov, A K; Zamay, T N; Savchenko, A A; Ingevatkin, E V; Titova, N M; Kolovskaya, O S; Luzan, N A; Silkin, P P; Kuznetsova, S A

    2016-03-01

    The article presents the results of investigation of antitumor properties of platinum-arabinogalactan complex. We showed the ability of the complex to inhibit the growth of Ehrlich ascites tumor cells. It is found that the distribution of the platinum-arabinogalactan complex is not specific only for tumor cells in mice. The complex was found in all tissues and organs examined (ascites cells, embryonic cells, kidney, and liver). The mechanism of action of the arabinogalactan-platinum complex may be similar to cisplatin as the complex is able to accumulate in tumor cells.

  12. Mechanism of Platinum Derivatives Induced Kidney Injury

    Directory of Open Access Journals (Sweden)

    Feifei YAN

    2015-09-01

    Full Text Available Platinum derivatives are the most widely used chemotherapeutic agents to treat solid tumors including ovarian, head and neck, and testicular germ cell tumors, lung cancer, and colorectal cancer. Two major problems exist, however, in the clinic use of platinum derivatives. One is the development of tumor resistance to the drug during therapy, leading to treatment failure. The other is the drug’s toxicity such as the cisplatin’s nephrotoxicity, which limits the dose that can be administered. This paper describes the mechanism of platinum derivatives induced kidney injury.

  13. Elaboration, physical and electrochemical characterizations of CO tolerant PEMFC anode materials. Study of platinum-molybdenum and platinum-tungsten alloys and composites; Elaborations et caracterisations electrochimiques et physiques de materiaux d'anode de PEMFC peu sensibles a l'empoisonnement par CO: etude d'alliages et de composites a base de platine-molybdene et de platine-tungstene

    Energy Technology Data Exchange (ETDEWEB)

    Peyrelade, E.

    2005-06-15

    PEMFC development is hindered by the CO poisoning ability of the anode platinum catalyst. It has been previously shown that the oxidation potential of carbon monoxide adsorbed on the platinum atoms can be lowered using specific Pt based catalysts, either metallic alloys or composites. The objective is then to realize a catalyst for which the CO oxidation is compatible with the working potential of a PEMFC anode. In our approach, to enhance the CO tolerance of platinum based catalyst supported on carbon, we studied platinum-tungsten and platinum-molybdenum alloys and platinum-metal oxide materials (Pt-WO{sub x} and Pt-MoO{sub x}). The platinum based alloys demonstrate a small effect of the second metal towards the oxidation of carbon monoxide. The platinum composites show a better tolerance to carbon monoxide. Electrochemical studies on both Pt-MoO{sub x} and Pt-WO{sub x} demonstrate the ability of the metal-oxides to promote the ability of Pt to oxidize CO at low potentials. However, chrono-amperometric tests reveal a bigger influence of the tungsten oxide. Complex chemistry reactions on the molybdenum oxide surface make it more difficult to observe. (author)

  14. Comparison of different sample preparation methods for platinum determination in cultured cells by graphite furnace atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Man Xiao

    2017-01-01

    Full Text Available Background Platinum-based agents are widely used in chemotherapy against solid tumors and insufficient intracellular drug accumulation is one of the leading causes of platinum resistance which is associated with poor survival of tumor patients. Thus, the detection of intracellular platinum is pivotal for studies aiming to overcome platinum resistance. In the present study, we aimed to establish a reliable graphite furnace atomic absorption spectrometry (GFAAS-based assay to quantify the intracellular platinum content for cultured cells. Methods Several most commonly applied cell preparation methods, including 0.2% HNO3, 0.2% Triton X-100, concentrated nitric acid, RIPA combined with concentrated nitric acid and hydroxide, followed by GFAAS for platinum detection were compared in ovarian, cervical and liver cancer cell lines to obtain the optimal one, and parameters regarding linearity, accuracy, precision and sensitivity were evaluated. Influence of other metals on platinum detection and the storage conditions of samples were also determined. Results The treatment of cells with 0.2% HNO3 was superior to other approaches with fewer platinum loss and better repeatability. The recovery rate and precision of this method were 97.3%–103.0% and 1.4%–3.8%, respectively. The average recoveries in the presence of other metals were 95.1%–103.1%. The detection limit was 13.23 ug/L. The recovery rate of platinum remained acceptable even in cell samples stored in −20 °C or −80 °C for two months. Discussion After comparison, we found that 0.2% HNO3 was optimal for intracellular platinum quantification based on GFAAS, which presented values compatible with that of inductively-coupled plasma mass-spectrometry (ICP-MS, and this is partially attributed to the simplicity of this method. Moreover, the assay was proved to be accurate, sensitive, cost-effective and suitable for the research of platinum-based antitumor therapy.

  15. Role of bonding mechanisms during transfer hydrogenation reaction on heterogeneous catalysts of platinum nanoparticles supported on zinc oxide nanorods

    Science.gov (United States)

    Al-Alawi, Reem A.; Laxman, Karthik; Dastgir, Sarim; Dutta, Joydeep

    2016-07-01

    For supported heterogeneous catalysis, the interface between a metal nanoparticle and the support plays an important role. In this work the dependency of the catalytic efficiency on the bonding chemistry of platinum nanoparticles supported on zinc oxide (ZnO) nanorods is studied. Platinum nanoparticles were deposited on ZnO nanorods (ZnO NR) using thermal and photochemical processes and the effects on the size, distribution, density and chemical state of the metal nanoparticles upon the catalytic activities are presented. The obtained results indicate that the bonding at Pt-ZnO interface depends on the deposition scheme which can be utilized to modulate the surface chemistry and thus the activity of the supported catalysts. Additionally, uniform distribution of metal on the catalyst support was observed to be more important than the loading density. It is also found that oxidized platinum Pt(IV) (platinum hydroxide) provided a more suitable surface for enhancing the transfer hydrogenation reaction of cyclohexanone with isopropanol compared to zero valent platinum. Photochemically synthesized ZnO supported nanocatalysts were efficient and potentially viable for upscaling to industrial applications.

  16. Synthesis of Diacetyl Curcumin Metal ( Copper, Platinum)Complexes and Its Interaction with ctDNA%二乙酰姜黄素金属(铜,铂)配合物的合成及其与ctDNA的键合作用

    Institute of Scientific and Technical Information of China (English)

    姜波; 魏冬; 范九良; 汪佳凤; 周双生

    2012-01-01

    以姜黄素为原料,合成了二乙酰姜黄素(H2L)及其铜(Ⅱ)和铂(Ⅱ)配合物(CuL2和PtL2),其结构经1H NMR,IR,MS和元素分析确认.采用UV-Vis测定法和循环伏安法研究了CuL2和PtL2与ctDNA的相互作用.结果表明,CuL2和PtL2与ctDNA的作用属嵌插作用模式.%Diacetyl Curcumin(H2L) and its metal[copper( II ) , platinum( H ) ] complex, CuL2 and PtL2, were synthesized from curcumin. The structures were characterized by 1H NMR, IR, MS and elemental analysis. The interactions of the CuL2 and PtL2 with ctDNA were studied by UV-Vis test method and cyclic voltammetry method. The results showed that interactions model of CuL2 and PtL2 with ctDNA was presumably intercalative model.

  17. Platinum-Resistor Differential Temperature Sensor

    Science.gov (United States)

    Kolbly, R. B.; Britcliffe, M. J.

    1985-01-01

    Platinum resistance elements used in bridge circuit for measuring temperature difference between two flowing liquids. Temperature errors with circuit are less than 0.01 degrees C over range of 100 degrees C.

  18. VB Platinum Tile & Carpet, Inc. Information Sheet

    Science.gov (United States)

    VB Platinum Tile & Carpet, Inc. (the Company) is located in Bristow, Virginia. The settlement involves renovation activities conducted at a property constructed prior to 1978, located in Washington, DC.

  19. Stabilizing platinum in phosphoric acid fuel cells

    Science.gov (United States)

    Remick, R. J.

    1982-01-01

    Platinum sintering on phosphoric acid fuel cell cathodes is discussed. The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst dispersed on a conductive carbon support to minimize both cathode polarization and fabrication costs. During operation, however, the active surface area of these electrodes decreases, which in turn leads to decreased cell performance. This loss of active surface area is a major factor in the degradation of fuel cell performance over time.

  20. Accuracy of thermistors and thermocouples as flow-measuring devices for detecting hypopnoeas.

    Science.gov (United States)

    Farré, R; Montserrat, J M; Rotger, M; Ballester, E; Navajas, D

    1998-01-01

    The aim of this work was to assess the accuracy of thermistors/thermocouples as devices for detecting hypopnoeas in sleep studies. Conventional thermistor/thermocouples were studied with a respiratory model allowing the simulation of inspiratory (22 degrees C) and expiratory (37 degrees C) flows. The thermistor signal (V'th) was compared with a pneumotachograph (V'th): 1) for sinusoidal and square-wave airflows (+/-0.05 to +/-0.8 L.s(-1), 10-20 breaths.min(-1) (bpm)); 2) when changing the distance from the thermistor to the nose (0-20 mm); and 3) when doubling the section of the nostrils. The thermistor was strongly nonlinear and flow reductions (hypopnoeas) were underestimated: a 50% reduction in V' (+/-0.5 L.s(-1), 15 bpm, sinusoidal) resulted in only an 18% reduction in V'th. V'th depended considerably on the airflow pattern: for V'=+/-0.5 L.s(-1), V'th increased by 100% from sinusoidal (20 bpm) to square-wave (10 bpm). For V'=+/-0.5 L.s(-1), 15 bpm, sinusoidal flow, V'th increased by 79% when the distance thermistor-nose varied from 20-0 mm, and V'th decreased by 37% when doubling the nose section. We concluded that thermistor/thermocouples are inaccurate flow-measuring devices when used at the airflow conditions typical of sleep studies. Their use for quantifying hypopnoeas may lead to considerable underdetection of these respiratory events.

  1. 从铂钯精矿中提取金、铂、钯工艺研究%Research on Extraction of Gold, Platinum and Palladium From Palladium-Platinum Concentrate

    Institute of Scientific and Technical Information of China (English)

    王兴; 崔家友; 张善辉; 陶明光

    2015-01-01

    针对在处理铜阳极泥过程中产生的铂钯精矿,采用电控除杂-大氯化溶解Au、Pt、Pd-氯化铵共沉铂钯-SO2还原金-水煮分离铂钯-铂钯精炼工艺提取金、铂、钯。铂、钯回收率98%以上,金的回收率为99%。该工艺具有成本低、操作简单、贵金属回收率高等优点。%In connection with the Platinum and Palladium Concentrates produced in the course of processing copper anode slime, utilizing the process of electronically controlled impurity-large chloride dissolving gold, platinum, palladium-ammonium chloride coprecipitating platinum and palladium-SO2 restoring gold-separation platinum and palladium by boiling to refine platinum and palladium. The recovery rate of platinum and palladium is over 98%, the recovery rate of gold reaches to 99%. The process has the advantage of low cost , simple operation, high precious metals recovery.

  2. A Multi-channel Pre-processing Circuit for Signals from Thermocouple/Thermister

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper,a new developed multi-channel pre-processing circuit for signals from temperature sensor was introduced in brief.This circuit was developed to collect and amplify the signals from temperature sensor.This is a universal circuit.It can be used to process the signals from thermocouples and also used to process signals from thermistors.This circuit was mounted in a standard box(440W×405D×125H mm)as an instrument.The

  3. An Explicit Approach Toward Modeling Thermo-Coupled Deformation Behaviors of SMPs

    Directory of Open Access Journals (Sweden)

    Hao Li

    2017-03-01

    Full Text Available A new elastoplastic J 2 -flow models with thermal effects is proposed toward simulating thermo-coupled finite deformation behaviors of shape memory polymers. In this new model, an elastic potential evolving with development of plastic flow is incorporated to characterize the stress-softening effect at unloading and, moreover, thermo-induced plastic flow is introduced to represent the strain recovery effect at heating. It is shown that any given test data for both effects may be accurately simulated by means of direct and explicit procedures. Numerical examples for model predictions compare well with test data in literature.

  4. The contributions to drift of positive and negative thermoelements in type K MIMS thermocouples

    Science.gov (United States)

    Scervini, M.; Rae, C.

    2013-09-01

    As part of the European project HEATTOP a study on drift of MIMS type K thermocouples above 1000°C has been undertaken: in particular the investigation focused on type K thermoelements of Rescal composition. The approach of this study is based on separating the contributions of each thermoelement to the drift which allows a deeper level of understanding of the contributions of different metallurgical modifications for each thermoelement. At temperature above 1000°C contamination of the thermoelements from the sheath becomes an important factor. The negative thermoelement is particularly prone to drift in MIMS configurations.

  5. Thermocouple Positioning For The Application Of The Non-Integer System Identification Approach To HIFIRE-5 Fins

    Science.gov (United States)

    Lohle, Stefan; Bohrk, Hannah; Fuchs, Ulf

    2011-05-01

    The German Aerospace Center developed a ceramic fin experiment (FinEx) for HIFiRE-5 flight in order to test the performance of new structure designs during hyper- sonic flight. Aero-thermal analysis is provided by 8 thermocouple data channels for all four symmetrically arranged fins. In this paper the analysis of the geometry and thermophysical characteristics of the fins to optimize thermocouple positioning is discussed. The main goal is to gather as much information as possible from these few temperature sensors in these three dimensional structures. Not only is the absolute temperature value of interest but also the reason of the temperature rise. A thorough calculation of the temperature gradients in the fin structure is used to define an optimal positioning layout, where particular focus lies on the localization of the heat fluxes at the surface from the in-depth thermocouple measurement. In conclusion, two fins are equipped with 3 thermocouples each and two are equipped with only 1 thermocouple. The paper closes with some first results based on the calibration data of the fins and the nominal trajectory values.

  6. On exact solutions and numerics for cold, shallow, and thermocoupled ice sheets

    CERN Document Server

    Bueler, E; Brown, Jed; Bueler, Ed

    2006-01-01

    This three section report can be regarded as an extended appendix to (Bueler, Brown, and Lingle 2006). First we give the detailed construction of an exact solution to a standard continuum model of a cold, shallow, and thermocoupled ice sheet. The construction is by calculation of compensatory accumulation and heat source functions which make a chosen pair of functions for thickness and temperature into exact solutions of the coupled system. The solution we construct here is ``TestG'' in (Bueler and others, 2006) and the steady state solution ``Test F'' is a special case. In the second section we give a reference C implementation of these exact solutions. In the last section we give an error analysis of a finite difference scheme for the temperature equation in the thermocoupled model. The error analysis gives three results, first the correct form of the Courant-Friedrichs-Lewy (CFL) condition for stability of the advection scheme, second an equation for error growth which contributes to understanding the famo...

  7. Unsaturated platinum-rhenium cluster complexes. Synthesis, structures and reactivity.

    Science.gov (United States)

    Adams, Richard D; Captain, Burjor; Smith, Mark D; Beddie, Chad; Hall, Michael B

    2007-05-09

    Two new compounds PtRe3(CO)12(PBut3)(micro-H)3, 9, and PtRe2(CO)9(PBut3)(micro-H)2, 10, were obtained from the reaction of Pt(PBut3)2 with Re3(CO)12(micro-H3), 8, at room temperature. Compound 9 contains a butterfly cluster of four metals formed by the insertion of the platinum atom from a Pt(PBut3) group into one of the hydride-bridged metal-metal bonds of 8. The three hydrido ligands are bridging ligands across each of three new Pt-Re bonds. Compound 10 contains a triangular PtRe2 cluster with two hydrido ligands; one bridges a Pt-Re bond, and the other bridges the Re-Re bond. The new compound Pt2Re2(CO)7(PBut3)2(micro-H)2, 11, was obtained from the reaction of 8 with Pt(PBut3)2 in hexane at reflux. Compound 11 was also obtained from 10 by reaction with an additional quantity of Pt(PBut3)2. Compound 11 contains a tetrahedral cluster of four metal atoms with two dynamically active hydrido ligands. A CO ligand on one of the two platinum atoms also exchanges between the two platinum atoms rapidly on the NMR time scale. Compound 11 is electronically unsaturated and was found to add hydrogen at room temperature to form the tetrahydrido cluster complex, Pt2Re2(CO)7(PBut3)2(micro-H)4, 12. Compound 12 has a structure similar to 11 but contains one triply bridging hydrido ligand, two edge bridging hydrido ligands, and one terminal hydrido ligand on one of the two platinum atoms. A kinetic isotope effect D/H of 1.5(1) was determined for the addition of H2 to 11. Hydrogen can be eliminated from 12 by heating to 97 degrees C or by the application of UV-vis irradiation at room temperature. Compound 12 adds CO at room temperature to yield the complex Pt2Re2(CO)8(PBut3)2(micro-H)4, 13, which contains a planar cluster of four metal atoms with a Pt-Pt bond and four edge bridging hydrido ligands. Compounds 11 and 12 react with Pt(PBut3)2 to yield the known five metal cluster complexes Pt3Re2(CO)6(PBut3)3(micro-H)2, 14, and Pt3Re2(CO)6(PBut3)3(micro-H)4, 15, respectively. Density

  8. 热电偶的选型及误差分析%Thermocouple type selection and error analysis

    Institute of Scientific and Technical Information of China (English)

    张丽

    2012-01-01

      热电偶是工业上常用的温度检测元件,它构造简单、测量范围广、精度高。在实际使用中,若热电偶选型错误,或者测量时操作不当,均会导致测量数据失真。主要介绍了热电偶的正确选择、使用及解决误差的办法。%  thermocouple is common industrial temperature detection device, it has the advantages of simple structure, wide measuring range, high precision. In actual use, if the thermocouple type errors, or when measuring the improper operation, will lead to the distortion of measurement data. Mainly introduces the correct selection of the use of thermocouple, and the solution error approach.

  9. EMF CHANGES MADE BY COLD DRAWING AND HEATING TREATMENT IN TYPE K HEAVY-GAUGE SHEATHED THERMOCOUPLE CABLES

    Institute of Scientific and Technical Information of China (English)

    赵容斌; 李冠军

    2002-01-01

    The electromotive force (EMF) changes in type K heavy-gauge sheathed thermocouple cables was investigated. To cope with this discrepancy owing to EMF steep reduction and understand the difference between type K heavy-gauge sheathed thermocouple cables and small ones, the affects of EMF from sheath pipe, drawing times, annealing temperature, annealing time and annealing way were mainly studied and appropriately analyzed. The results show the change in the thermal EMF is related with the residual stress and crystal defects, which are imparted by cold work during manufacture. The affects of cold work can be removed by annealing. Finally, a feasible way of fabricating heavy-gauge sheathed thermocouples was suggested according to practical situation.

  10. A fine-wire thermocouple probe for measurement of stagnation temperatures in real gas hypersonic flows of nitrogen

    Science.gov (United States)

    Hollis, Brian R.; Griffith, Wayland C.; Yanta, William J.

    1991-01-01

    A fine-wire thermocouple probe was used to determine freestream stagnation temperatures in hypersonic flows. Data were gathered in a N2 blowdown wind tunnel with runtimes of 1-5 s. Tests were made at supply pressures between 30 and 1400 atm and supply temperatures between 700 and 1900 K, with Mach numbers of 14 to 16. An iterative procedure requiring thermocouple data, pilot pressure measurements, and supply conditions was used to determine test cell stagnation temperatures. Probe conduction and radiation losses, as well as real gas behavior of N2, were accounted for during analysis. Temperature measurement error was found to be 5 to 10 percent. A correlation was drawn between thermocouple diameter Reynolds number and temperature recovery ratio. Transient probe behavior was studied and was found to be adequate in temperature gradients up to 1000 K/s.

  11. Formic Acid Electrooxidation by a Platinum Nanotubule Array Electrode

    Directory of Open Access Journals (Sweden)

    Eric Broaddus

    2013-01-01

    Full Text Available One-dimensional metallic nanostructures such as nanowires, rods, and tubes have drawn much attention for electrocatalytic applications due to potential advantages that include fewer diffusion impeding interfaces with polymeric binders, more facile pathways for electron transfer, and more effective exposure of active surface sites. 1D nanostructured electrodes have been fabricated using a variety of methods, typically showing improved current response which has been attributed to improved CO tolerance, enhanced surface activity, and/or improved transport characteristics. A template wetting approach was used to fabricate an array of platinum nanotubules which were examined electrochemically with regard to the electrooxidation of formic acid. Arrays of 100 and 200 nm nanotubules were compared to a traditional platinum black catalyst, all of which were found to have similar surface areas. Peak formic acid oxidation current was observed to be highest for the 100 nm nanotubule array, followed by the 200 nm array and the Pt black; however, CO tolerance of all electrodes was similar, as were the onset potentials of the oxidation and reduction peaks. The higher current response was attributed to enhanced mass transfer in the nanotubule electrodes, likely due to a combination of both the more open nanostructure as well as the lack of a polymeric binder in the catalyst layer.

  12. Surface segregations in platinum-based alloy nanoparticles

    Science.gov (United States)

    Yamakawa, Shunsuke; Asahi, Ryoji; Koyama, Toshiyuki

    2014-04-01

    A phase-field model that describes the radial distributions of the ordered-disordered phase and surface segregation in a single-alloy nanoparticle is introduced to clarify the overall behavior of surface segregation of various Pt-based alloy nanoparticles. One of the obstacles to apply a platinum-transition metal alloy as a cathode electro-catalyst of a polymer electrolyte fuel cell is the need to ensure the retention of the designed surface composition in an alloy nanoparticle against the alloy combinations, a particle size, and heat treatment. From the results of calculations for CrPt, FePt, CoPt, NiPt, CuPt, PdPt, IrPt, and AuPt binary nanoparticles with diameters below 10 nm at 973.15 K, the compositional variation within a single particle was found to depend on the balance between the atomic interaction within particles and the surface free energy. In addition, the obtained specific steady-state composition of the surface varied significantly with alloy combination and particle diameter. Based on the general tendencies of a binary system to exhibit segregation, attempts to control the amount of platinum segregation on the surface using a ternary-alloy system were examined.

  13. Platinum-group elements: so many excellent properties

    Science.gov (United States)

    Zientek, Michael L.; Loferski, Patricia J.

    2014-01-01

    The platinum-group elements (PGE) include platinum, palladium, rhodium, ruthenium, iridium, and osmium. These metals have similar physical and chemical properties and occur together in nature. The properties of PGE, such as high melting points, corrosion resistance, and catalytic qualities, make them indispensable to many industrial applications. PGE are strategic and critical materials for many nations because they are essential for important industrial applications but are mined in a limited number of places and have no adequate substitutes. Exploration and mining companies have found approximately 104,000 metric tons of PGE (with minor gold) in mineral deposits around the world that could be developed. For PGE, almost all known production and resources are associated with three geologic features: the Bushveld Complex, a layered mafic-to-ultramafic intrusion in South Africa; the Great Dyke, a layered mafic-to-ultramafic intrusion in Zimbabwe; and sill-like intrusions associated with flood basalts in the Noril’sk-Talnakh area, Russia. To help predict where PGE supplies might be located, USGS scientists study how and where PGE resources are concentrated in the Earth's crust and use that knowledge to assess the likelihood that undiscovered PGE deposits may exist. Techniques used for assessing mineral resources were developed by the USGS to support the stewardship of Federal lands and evaluate mineral resource availability in a global context. The USGS also compiles statistics and information on the worldwide supply, demand, and flow of PGE. These data are all used to inform U.S. national policymakers.

  14. Sulfur tolerant zeolite supported platinum catalysts for aromatics hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Bergem, Haakon

    1997-12-31

    The increased demand for transportation fuels at the expence of heavier fuel oil has forced the refinery industry to expand their conversion capacity with hydrotreating as one of the key processes. A shift towards more diesel powered vehicles along with tightening fuel regulations demanding cleaner fuels has lead to increasing interest in catalytic processes for the manufacturing of such environmentally acceptable fuels. This provides the motivation for this thesis. Its main objective was to study possible catalysts active for desulfurization, hydrogenation, and ring-opening of aromatics all in the presence of sulfur. A close examination of the physical properties and kinetical behaviour of the chosen catalysts has been performed. A high pressure reactor setup was designed and built for activity measurements. Zeolite supported platinum catalysts were prepared and both the metal and acid functions were characterized utilizing various experimental techniques. Hydrogenation of toluene was used as a model reaction and the effect of sulfur adsorption on the activity and kinetic behaviour of the catalysts was investigated. The catalyst samples showed hydrogenation activities comparable to a commercial Pt/Al2O3 catalyst. There were no clear differences in the effect of the various sulfur compounds studied. Platinum supported on zeolite Y gave considerably more sulfur tolerant catalysts compared to Al2O3 as support. 155 refs., 58 figs., 36 tabs.

  15. Sign of inverse spin Hall voltages generated by ferromagnetic resonance and temperature gradients in yttrium iron garnet platinum bilayers

    NARCIS (Netherlands)

    Schreier, Michael; Bauer, Gerrit E. W.; Vasyuchka, Vitaliy I.; Flipse, Joost; Uchida, Ken-ichi; Lotze, Johannes; Lauer, Viktor; Chumak, Andrii V.; Serga, Alexander A.; Daimon, Shunsuke; Kikkawa, Takashi; Saitoh, Eiji; van Wees, Bart J.; Hillebrands, Burkard; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2015-01-01

    We carried out a concerted effort to determine the absolute sign of the inverse spin Hall effect voltage generated by spin currents injected into a normal metal. We focus on yttrium iron garnet (YIG)vertical bar platinum bilayers at room temperature, generating spin currents by microwaves and temper

  16. Selective oxidation of glycerol by using a hydrotalcite-supported platinum catalyst under atmospheric oxygen pressure in water.

    Science.gov (United States)

    Tsuji, Akihiro; Rao, Kasanneni Tirumala Venkateswara; Nishimura, Shun; Takagaki, Atsushi; Ebitani, Kohki

    2011-04-18

    A hydrotalcite-supported platinum (Pt/HT) catalyst was found to be a highly active and selective heterogeneous catalyst for glycerol oxidation in pure water under atmospheric oxygen pressure in a high glycerol/metal molar ratio up to 3125. High selectivity toward glyceric acid (78 %) was obtained even at room temperature under air atmosphere. The Pt/HT catalyst selectively oxidized the primary hydroxyl group of 1,2-propandiol to give the corresponding carboxylic acid (lactic acid) as well as glycerol. The activity of the catalyst was greatly influenced by the Mg/Al ratio of hydrotalcite. Glycerol conversion increased with increasing the Mg/Al ratio of hydrotalcite (from trace to 56 %). X-ray absorption fine structure (XAFS) measurements indicated that the catalytic oxidation activity was proportional to the metallic platinum concentration, and more than 35 % of metallic platinum was necessary for this reaction. TEM measurements and titration analysis by using benzoic acid suggested that the solid basicity of hydrotalcite plays important roles in the precise control of platinum size and metal concentration as well as the initial promotion of alcohol oxidation.

  17. computer modeling ter modeling ter modeling of platinum reforming ...

    African Journals Online (AJOL)

    eobe

    naphtha to complex chemical reactions, at h temperature and ... at is leaving any stage of the platinum reforming reactors in terms of ... In this study, only platinum reforming .... IV. Hydrocracking of paraffinic hydrocarbons: +. →. ( +. +. +. +. ) (18).

  18. Novel platinum black electroplating technique improving mechanical stability.

    Science.gov (United States)

    Kim, Raeyoung; Nam, Yoonkey

    2013-01-01

    Platinum black microelectrodes are widely used as an effective neural signal recording sensor. The simple fabrication process, high quality signal recording and proper biocompatibility are the main advantages of platinum black microelectrodes. When microelectrodes are exposed to actual biological system, various physical stimuli are applied. However, the porous structure of platinum black is vulnerable to external stimuli and destroyed easily. The impedance level of the microelectrode increases when the microelectrodes are damaged resulting in decreased recording performance. In this study, we developed mechanically stable platinum black microelectrodes by adding polydopamine. The polydopamine layer was added between the platinum black structures by electrodeposition method. The initial impedance level of platinum black only microelectrodes and polydopamine added microelectrodes were similar but after applying ultrasonication the impedance value dramatically increased for platinum black only microelectrodes, whereas polydopamine added microelectrodes showed little increase which were nearly retained initial values. Polydopamine added platinum black microelectrodes are expected to extend the availability as neural sensors.

  19. Surfactant gel adsorption of platinum(II), (IV) and palladium(II) as chloro-complexes and kinetic separation of palladium from platinum using EDTA.

    Science.gov (United States)

    Murakami, Yoshiko; Hiraiwa, Kaoru; Sasaki, Yoshiaki; Fujiwara, Isamu; Tagashira, Shoji

    2007-09-01

    A micellar solution of cetylpyridinium chloride (CPC) can separate into two phases due to a temperature change or to the addition of salts. Platinum(II), (IV) and palladium(II) reacted with chloride ions to form stable anionic complexes of PtCl4(2-), PtCl6(2-) and PdCl4(2-), respectively, and were adsorbed onto the CPC gel phase. The CPC phase plays the role of an ion-exchange adsorbent for the anionic complexes. By such a procedure, the precious metals of platinum and palladium could be separated from base metals such as copper, zinc and iron. The kinetic separation was performed by a ligand exchange reaction of the palladium(II) chloro-complex with EDTA at 60 degrees C. The anionic palladium(II)-EDTA complex could not bind the opposite charged CP+ and was desorbed from the CPC phase. In the aqueous phase, the recovery of palladium(II) by the double-desorption was 101.1 +/- 1.2%. The platinum(II) and (IV) chloro-complexes were stable for at least 30 min and remained in the CPC phase.

  20. Platinum uptake from chloride solutions using biosorbents

    Directory of Open Access Journals (Sweden)

    Mehmet Hakan Morcali

    2013-04-01

    Full Text Available Present work investigates platinum uptake from synthetically prepared, dilute platinum-bearing solutions using biomass residues, i.e. pistachio nut shell and rice husk, which are abundant in Turkey, and provides a comparison between these two biosorbents. Effects of the different uptake parameters, sorbent dosage, contact time, temperature and pH of solution on platinum uptake (% were studied in detail on a batch sorption. Before the pistachio nut shell was activated, platinum uptake (% was poor compared to the rice husk. However, after the pistachio nut shell was activated at 1000 °C under an argon atmosphere, the platinum uptake (% increased two-fold. The pistachio nut shell (original and activated and rice husk were shown to be better than commercially available activated carbon in terms of adsorption capacity. These two sorbents have also been characterized by FTIR and SEM. Adsorption equilibrium data best complied with the Langmuir isotherm model. Maximum adsorption capacities, Qmax, at 25 °C were found to be 38.31 and 42.02 mg.g- 1for the activated pistachio nut shell and rice husk, respectively. Thermodynamic calculations using the measured ∆H°, ∆S° and ∆G° values indicate that the uptake process was spontaneous and endothermic. The experimental data were shown to be fit the pseudo-second-order kinetic model.

  1. Study of improving working life of thermocouple%提高热电偶使用寿命的研究

    Institute of Scientific and Technical Information of China (English)

    李丽

    2016-01-01

    This paper introduces the Thermocouples used in blast furnace hot blast stove to mix the wind temperature detection damage failure analysis,and How to improve the service life of the mixed wind temperature detection with thermocouple.%本文着重介绍了高炉热风炉混风温度检测用热电偶损坏故障分析以及如何提高混风温度检测用热电偶的使用寿命.

  2. Electrochemical Fabrication and Electrocatalytic Properties of Nanostructured Mesoporous Platinum Microelectrodes

    Institute of Scientific and Technical Information of China (English)

    Mengyan NIE; Joanne M. Elliott

    2005-01-01

    Electrodeposition from a lyotropic liquid crystal template medium was used to produce nanostructured platinum microelectrodes with high specific surface area and high mass transport efficiency. Compared to polished and conventional platinized microelectrodes, well-ordered nanostructured platinum microelectrodes exhibited enhanced electrocatalytic properties for oxygen and ascorbic acid, whilst well-ordered nanostructured platinum microelectrodes offered improved electrocatalytic properties for oxygen reduction compared to disordered nanostructured platinum microelectrodes.

  3. Metals and metal compounds in cancer treatment.

    Science.gov (United States)

    Desoize, Bernard

    2004-01-01

    Metals and metal compounds have been used in medicine for several thousands of years. In this review we summarized the anti-cancer activities of the ten most active metals: arsenic, antimony, bismuth, gold, vanadium, iron, rhodium, titanium, gallium and platinum. The first reviewed metal, arsenic, presents the anomaly of displaying anti-cancer and oncogenic properties simultaneously. Some antimony derivatives, such as Sb2O3, salt (tartrate) and organic compounds, show interesting results. Bismuth directly affects Helicobacter pylori and gastric lymphoma; the effects of bismuth complexes of 6-mercaptopurine are promising. Gold(I) and (III) compounds show anti-tumour activities, although toxicity remains high. Research into the potential use of gold derivatives is still ongoing. Several derivatives of vanadium show anti-proliferative activity, but their toxicity must be overcome. Several pieces of evidence indicate that iron deprivation could be an excellent therapeutic approach; furthermore, it is synergistic with classic anti-cancer drugs. Rhodium belongs to the same group as platinum and it also presents interesting activity, but with the same nephrotoxicity. Several rhodium compounds have entered phase I clinical trials. In contrast to the platinum complexes, titanium derivatives showed no evidence of nephrotoxicity or myelotoxicity; titanocene dichloride is undergoing clinical trial. The anti-proliferative effect of gallium could be related to its competition with the iron atom; in addition a derivative appears to reverse the multidrug resistance. The last metal reviewed, platinum, has given some of the very best anti-cancer drugs. Four derivatives are used today in the clinic; their mechanism of action and of resistance are described.

  4. Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Michael Edward [Univ. of California, Berkeley, CA (United States)

    2008-09-01

    Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.

  5. Extensions of Callendar's equations for platinum resistance thermometry

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1969-01-01

    measurements where the platinum thermometer and the measurement means may be less than ideal. To this end. Callendar's definition of platinum temperature is generalized to mean the temperature found by linear interpolation with a platinum thermometer between given fixed points and using a given measurement...

  6. Platinum Publications as of April 30, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  7. Platinum Publications, September 30–October 27, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  8. Platinum Publications as of June 25, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  9. Platinum Publications, July 1–July 28, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  10. Platinum Publications as of March 6, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  11. Platinum Publications, October 1–29, 2015 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  12. Platinum Publications, December 1–December 29, 2016 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  13. Platinum Publications as of May 29, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  14. Platinum Publications as of September 25, 2014 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  15. Platinum Publications, January 26–February 28, 2017 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  16. Platinum Publications as of December 3, 2013 | Poster

    Science.gov (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  17. Deposition of the platinum crystals on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new technique and the affecting factors for depositing platinum on the carbon nanotubes were investigated. The results show that the deposited platinum crystals in the atmosphere of hydrogen or nitrogen have a small size and a homogeneous distribution on the surface of the carbon nanotubes. The pretreatment would decrease the platinum particles on the carbon nanotubes significantly.

  18. 76 FR 8627 - Revision of Class E Airspace; Platinum, AK

    Science.gov (United States)

    2011-02-15

    ... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Platinum, AK AGENCY: Federal... Platinum, AK, to accommodate the addition of a Standard Instrument Approach Procedure (SIAP), at the Platinum Airport. The FAA is taking this action to enhance safety and management of Instrument Flight...

  19. Autonomous movement of platinum-loaded stomatocytes.

    Science.gov (United States)

    Wilson, Daniela A; Nolte, Roeland J M; van Hest, Jan C M

    2012-02-26

    Polymer stomatocytes are bowl-shaped structures of nanosize dimensions formed by the controlled deformation of polymer vesicles. The stable nanocavity and strict control of the opening are ideal for the physical entrapment of nanoparticles which, when catalytically active, can turn the stomatocyte morphology into a nanoreactor. Herein we report an approach to generate autonomous movement of the polymer stomatocytes by selectively entrapping catalytically active platinum nanoparticles within their nanocavities and subsequently using catalysis as a driving force for movement. Hydrogen peroxide is free to access the inner stomatocyte cavity, where it is decomposed by the active catalyst (the entrapped platinum nanoparticles) into oxygen and water. This generates a rapid discharge, which induces thrust and directional movement. The design of the platinum-loaded stomatocytes resembles a miniature monopropellant rocket engine, in which the controlled opening of the stomatocytes directs the expulsion of the decomposition products away from the reaction chamber (inner stomatocyte cavity).

  20. Accumulation of platinum group elements by the marine gastropod Littorina littorea

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, Rachel [School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom); Turner, Andrew, E-mail: aturner@plymouth.ac.uk [School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

    2011-04-15

    The accumulation and trophic transfer of the platinum group elements (PGE): Rh, Pd and Pt; have been studied in short-term (5 day) exposures conducted in aquaria containing the marine macroalga, Ulva lactuca, and/or the grazing mollusc, Littorina littorea. Metals added to sea water (to concentrations of 20 {mu}g L{sup -1}) were taken up by U. lactuca in the order Rh, Pt > Pd and by L. littorea in the order Pd {>=} Pt {>=} Rh, with greatest metal accumulation in the latter generally occurring in the visceral complex and kidney. When fed contaminated alga, accumulation of Rh and Pd by L. littorea, relative to total available metal, increased by an order of magnitude, while accumulation of Pt was not readily detected. We conclude that the diet is the most important vector for accumulation of Rh and Pd, while accumulation of Pt appears to proceed mainly from the aqueous phase. - Research highlights: > Platinum group elements are accumulated by, Littorina littorea. > The aqueous phase and diet are important vehicles for Rh and Pd accumulation by the snail. > Grazing molluscs may serve as biomonitors of coastal PGE contamination. - Platinum group elements are accumulated by the marine snail, Littorina littorea, from both the aqueous phase and the diet.

  1. Simultaneous Platinum and Copper Ion Attachment to a Human Copper Chaperone Protein

    Science.gov (United States)

    Hodak, Miroslav; Cvitkovic, John; Yu, Corey; Dmitriev, Oleg; Kaminski, George; Bernholc, Jerry

    2015-03-01

    Cisplatin is a potent anti-cancer drug based on a platinum ion. However, its effectiveness is decreased by cellular resistance, which involves cisplatin attaching to copper transport proteins. One of such proteins is Atox1, where cisplatin attaches to the copper binding site. Surprisingly, it was shown that both cisplatin and copper can attach to Atox1 at the same time. To study this double metal ion attachment, we use the KS/FD DFT method, which combines Kohn-Sham DFT with frozen-density DFT to achieve efficient quantum-mechanical description of explicit solvent. Calculations have so far investigated copper ion attachment to CXXC motifs present in Atox1. The addition of the platinum ion and the competition between the two metals is currently being studied. These calculations start from a molecular mechanics (MM) structural model, in which glutathione groups provide additional ligands to the Pt ion. Our goals are to identify possible Cu-Pt structures and to determine whether copper/platinum attachment is competitive, independent, or cooperative. Results will be compared to the 1H, N1 5 -HSQC NMR experiments, in which binding of copper and cisplatin to Atox1 produces distinct secondary chemical shift signatures, allowing for kinetic studies of simultaneous metal binding.

  2. Behavior of platinum(iv) complexes in models of tumor hypoxia: cytotoxicity, compound distribution and accumulation.

    Science.gov (United States)

    Schreiber-Brynzak, Ekaterina; Pichler, Verena; Heffeter, Petra; Hanson, Buck; Theiner, Sarah; Lichtscheidl-Schultz, Irene; Kornauth, Christoph; Bamonti, Luca; Dhery, Vineet; Groza, Diana; Berry, David; Berger, Walter; Galanski, Markus; Jakupec, Michael A; Keppler, Bernhard K

    2016-04-01

    Hypoxia in solid tumors remains a challenge for conventional cancer therapeutics. As a source for resistance, metastasis development and drug bioprocessing, it influences treatment results and disease outcome. Bioreductive platinum(iv) prodrugs might be advantageous over conventional metal-based therapeutics, as biotransformation in a reductive milieu, such as under hypoxia, is required for drug activation. This study deals with a two-step screening of experimental platinum(iv) prodrugs with different rates of reduction and lipophilicity with the aim of identifying the most appropriate compounds for further investigations. In the first step, the cytotoxicity of all compounds was compared in hypoxic multicellular spheroids and monolayer culture using a set of cancer cell lines with different sensitivities to platinum(ii) compounds. Secondly, two selected compounds were tested in hypoxic xenografts in SCID mouse models in comparison to satraplatin, and, additionally, (LA)-ICP-MS-based accumulation and distribution studies were performed for these compounds in hypoxic spheroids and xenografts. Our findings suggest that, while cellular uptake and cytotoxicity strongly correlate with lipophilicity, cytotoxicity under hypoxia compared to non-hypoxic conditions and antitumor activity of platinum(iv) prodrugs are dependent on their rate of reduction.

  3. Enhanced catalytic activity of solid and hollow platinum-cobalt nanoparticles towards reduction of 4-nitrophenol

    Science.gov (United States)

    Krajczewski, Jan; Kołątaj, Karol; Kudelski, Andrzej

    2016-12-01

    Previous investigations of hollow platinum nanoparticles have shown that such nanostructures are more active catalysts than their solid counterparts towards the following electrochemical reactions: reduction of oxygen, evolution of hydrogen, and oxidation of borohydride, methanol and formic acid. In this work we show that synthesised using standard galvanic replacement reaction (with Co templates) hollow platinum nanoparticles exhibit enhanced catalytic activity also towards reduction of 4-nitrophenol by sodium borohydride in water. Unlike in the case of procedures involving hollow platinum catalysts employed so far to carry out this reaction it is not necessary to couple analysed platinum nanoparticles to the surface of an electrode. Simplification of the analyzed reaction may eliminate same experimental errors. We found that the enhanced catalytic activity of hollow Pt nanoparticles is not only connected with generally observed larger surface area of hollow nanostructures, but is also due to the contamination of formed hollow nanostructures with cobalt, from which sacrificial templates used in the synthesis of hollow Pt nanostrustures have been formed. Because using sacrificial templates is a typical method of synthesis of hollow metal nanostructures, formed hollow nanoparticles are probably often contaminated, which may significantly influence their catalytic activity.

  4. Preparation of platinum modified titanium dioxide nanoparticles with the use of laser ablation in water.

    Science.gov (United States)

    Siuzdak, K; Sawczak, M; Klein, M; Nowaczyk, G; Jurga, S; Cenian, A

    2014-08-07

    We report on the preparation method of nanocrystalline titanium dioxide modified with platinum by using nanosecond laser ablation in liquid (LAL). Titania in the form of anatase crystals has been prepared in a two-stage process. Initially, irradiation by laser beam of a titanium metal plate fixed in a glass container filled with deionized water was conducted. After that, the ablation process was continued, with the use of a platinum target placed in a freshly obtained titania colloid. In this work, characterization of the obtained nanoparticles, based on spectroscopic techniques--Raman, X-ray photoelectron and UV-vis reflectance spectroscopy--is given. High resolution transmission electron microscopy was used to describe particle morphology. On the basis of photocatalytic studies we observed the rate of degradation process of methylene blue (MB) (a model organic pollution) in the presence of Pt modified titania in comparison to pure TiO2--as a reference case. Physical and chemical mechanisms of the formation of platinum modified titania are also discussed here. Stable colloidal suspensions containing Pt modified titanium dioxide crystalline anatase particles show an almost perfect spherical shape with diameters ranging from 5 to 30 nm. The TiO2 nanoparticles decorated with platinum exhibit much higher (up to 30%) photocatalytic activity towards the degradation of MB under UV illumination than pure titania.

  5. Epitaxial and non-epitaxial platinum, palladium and silver films on yttrium-stabilised zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Beck, Gesa, E-mail: gesa.beck@physik.uni-augsburg.de [Institute of Physics, University Augsburg, Universitaetsstrasse 1a, 86159 Augsburg (Germany); Bachmann, Christoph [Institute of Physical Chemistry, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen (Germany); Bretzler, Rita [Research Institute Precious Metals & Metals Chemistry, Katharinenstrasse 17, 73525 Schwaebisch Gmuend (Germany); Kmeth, Ralf [Institute of Physics, University Augsburg, Universitaetsstrasse 1a, 86159 Augsburg (Germany)

    2015-05-05

    Platinum, palladium and silver films have been prepared on differently orientated YSZ (yttrium-stabilised zirconia) substrates by PLD (pulsed laser deposition). The deposition temperatures for platinum were 200 °C and 400 °C, whereas palladium and silver were deposited only at 200 °C. The microstructure of the films depends on the particular metal, on the orientation of the substrate and on the deposition temperature. Platinum – deposited at 400 °C – forms single crystalline, epitaxial (111), (311) and (110) orientated as well as (111) orientated polycrystalline films. Platinum, palladium and silver – deposited at 200 °C – always form (111) orientated and polycrystalline films, in some cases also with a fraction of epitaxial grown grains. The formed microstructures were discussed on the basis of interface and surface energy minimization and structure zone models. - Highlights: • Pt, Pd and Ag films are prepared on differently orientated YSZ. • Substrate orientation and deposition temperature influences the microstructure. • Pt forms epitaxial and polycrystalline films. • Pd and Ag form polycrystalline films, sometimes with epitaxial grown grains. • The formed microstructures are described by energy minimization.

  6. 21 CFR 872.3060 - Noble metal alloy.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver,...

  7. Electrocatalytic activity of platinum nanoparticles supported on nanosilicon

    Energy Technology Data Exchange (ETDEWEB)

    Miu, M.; Kleps, I.; Danila, M.; Ignat, T.; Simion, M.; Bragaru, A.; Dinescu, A. [Laboratory of Nanotechnology, National Institute for Research and Development in Microtechnologies, Bucharest (Romania)

    2010-04-15

    Platinum (Pt) nanocatalysts were deposited on/inside of nanostructured silicon (nanoSi) matrix using physico-chemical methods, i.e. E-beam high vacuum Pt thin film and, respectively, chemically loaded Pt nanoparticles from hexachloroplatinic acid aqueous or alcoholic precursor solutions. High resolution morphological characterisations, completed by microstructural and compositional analyses have been performed to characterise the nanoSi catalyst support and to investigate the Pt thin film nanostructuration as well as the nanoparticle attachment and clustering processes, evidencing the controlling factors and conditions of the size, morphology and distribution. Furthermore, the experimental structures have been subjected to different electrochemical tests and it was revealed that significant improvement of the long term catalyst stability was achieved when the metal-porous Si nanoassemblies is formed, which represents a step closer to the realisation of the monolithic integrated Si-based microfabricated fuel cell. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  8. Tin-Platinum catalysts interactions on titania and silica

    Energy Technology Data Exchange (ETDEWEB)

    Nava, N. [Instituto Mexicano del Petroleo Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)], E-mail: tnava@imp.mx; Del Angel, P. [Instituto Mexicano del Petroleo Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Salmones, J. [Instituto Politecnico Nacional-ESIQIE UPALM, 07738 Mexico, D.F. (Mexico); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brasil (Brazil); Santiago, P. [Instituto de Fisica, UNAM, Mexico, D. F., 04510 Mexico (Mexico)

    2007-09-30

    Pt-Sn was supported on titania and silica, and the resulting interactions between the components in prepared samples and the resulting interactions between the components before and after treatment with hydrogen were characterized by Moessbauer spectroscopy, X-ray diffraction, Rietveld refinement, high-resolution transmission electron microscopy (HRTEM) and catalytic tests data. Results show the presence of Pt and SnO{sub 2} after calcinations, and Pt{sub 3}Sn, PtSn and PtSn{sub 3} after reduction. Rietveld analysis shows that some Ti{sup 4+} are replaced by Sn{sup 4+} atoms in the titania structure. Finally, HRTEM and the practically absence of activity observed confirms that metallic platinum is encapsulated.

  9. Chronic measurement of cardiac output in unanesthetized rats using miniature thermocouples.

    Science.gov (United States)

    Osborn, J W; Barber, B J; Quillen, E W; Abram, R J; Cowley, A W

    1986-12-01

    A thermodilution technique is described for measuring steady-state cardiac output (CO) in conscious rats for periods of 2-3 wk. The method utilizes small implantable aortic thermocouples inserted via the femoral artery at the time of placement of other chronic indwelling catheters. Data are presented to validate the accuracy and reproducibility of the technique by acute in situ comparison with electromagnetic flowmeter measurements. Responses in chronically instrumented rats were tested with hemorrhage and infusions of vasodilator and vasoconstrictor agents administered repeatedly over a period of 9 days. The results show that the system is capable of measuring CO chronically and provides reproducible responses for periods of at least several weeks. We conclude that these methods provide a single, inexpensive, and accurate way to measure steady-state CO in conscious, unrestrained rats.

  10. Tile Surface Thermocouple Measurement Challenges from the Orbiter Boundary Layer Transition Flight Experiment

    Science.gov (United States)

    Campbell, Charles H.; Berger, Karen; Anderson, Brian

    2012-01-01

    Hypersonic entry flight testing motivated by efforts seeking to characterize boundary layer transition on the Space Shuttle Orbiters have identified challenges in our ability to acquire high quality quantitative surface temperature measurements versus time. Five missions near the end of the Space Shuttle Program implemented a tile surface protuberance as a boundary layer trip together with tile surface thermocouples to capture temperature measurements during entry. Similar engineering implementations of these measurements on Discovery and Endeavor demonstrated unexpected measurement voltage response during the high heating portion of the entry trajectory. An assessment has been performed to characterize possible causes of the issues experienced during STS-119, STS-128, STS-131, STS-133 and STS-134 as well as similar issues encountered during other orbiter entries.

  11. High temperature thermocouple and heat flux gauge using a unique thin film-hardware hot juncture

    Science.gov (United States)

    Liebert, C. H.; Holanda, R.; Hippensteele, S. A.; Andracchio, C. A.

    1984-01-01

    A special thin film-hardware material thermocouple (TC) and heat flux gauge concept for a reasonably high temperature and high flux flat plate heat transfer experiment was fabricated and tested to gauge temperatures of 911 K. This concept was developed for minimal disturbance of boundary layer temperature and flow over the plates and minimal disturbance of heat flux through the plates. Comparison of special heat flux gauge Stanton number output at steady-state conditions with benchmark literature data was good and agreement was within a calculated uncertainty of the measurement system. Also, good agreement of special TC and standard TC outputs was obtained and the results are encouraging. Oxidation of thin film thermoelements was a primary failure mode after about 5 of operation.

  12. Simple method for measuring vibration amplitude of high power airborne ultrasonic transducer: using thermo-couple.

    Science.gov (United States)

    Saffar, Saber; Abdullah, Amir

    2014-03-01

    Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Recent Development in Simultaneous Multi-Element Determination of the Platinum Group Elements and Gold in Geological and Environmental Samples

    Institute of Scientific and Technical Information of China (English)

    任曼; 邓海琳

    2004-01-01

    In recent years, the modern methods of multi-element analysis of precious metals have attracted wide attention in scientific research and industry. The application and development in the decomposition of samples, separation and enrichment, and modern instrumental analysis of the platinum-group elements (PGEs) and gold in geological and environmental samples have been reviewed. Finally, the tendency of analysis of precious metals is also prospected.

  14. Engineering Platinum Alloy Electrocatalysts in Nanoscale for PEMFC Application

    Energy Technology Data Exchange (ETDEWEB)

    He, Ting [Idaho National Laboratory

    2016-03-01

    Fuel cells are expected to be a key next-generation energy source used for vehicles and homes, offering high energy conversion efficiency and minimal pollutant emissions. However, due to large overpotentials on anode and cathode, the efficiency is still much lower than theoretically predicted. During the past decades, considerable efforts have been made to investigate synergy effect of platinum alloyed with base metals. But, engineering the alloy particles in nanoscale has been a challenge. Most important challenges in developing nanostructured materials are the abilities to control size, monodispersity, microcomposition, and even morphology or self-assembly capability, so called Nanomaterials-by-Design, which requires interdisciplinary collaborations among computational modeling, chemical synthesis, nanoscale characterization as well as manufacturing processing. Electrocatalysts, particularly fuel cell catalysts, are dramatically different from heterogeneous catalysts because the surface area in micropores cannot be electrochemically controlled on the same time scale as more transport accessible surfaces. Therefore, electrocatalytic architectures need minimal microporous surface area while maximizing surfaces accessible through mesopores or macropores, and to "pin" the most active, highest performance physicochemical state of the materials even when exposed to thermodynamic forces, which would otherwise drive restructuring, crystallization, or densification of the nanoscale materials. In this presentation, results of engineering nanoscale platinum alloy particles down to 2 ~ 4 nm will be discussed. Based on nature of alloyed base metals, various synthesis technologies have been studied and developed to achieve capabilities of controlling particle size and particle microcomposition, namely, core-shell synthesis, microemulsion technique, thermal decomposition process, surface organometallic chemical method, etc. The results show that by careful engineering the

  15. Thermometry of the surface of human skin. A study on a model using thermocouples, thermistors, thermovision and thermodyes.

    Science.gov (United States)

    Flesch, U; Wegener, O H; Scheffler, A; Ernst, H

    1976-05-01

    The temperature of the surface of a model of human skin is measured using a recently developed probe to house a thermocouple or thermistor. The results are compared with thermovision and thermodye measurements. The effect on skin temperature of hot and cold vessels at various depths is investigated.

  16. Distortion of millimeter-wave absorption in biological media due to presence of thermocouples and other objects.

    Science.gov (United States)

    Alekseev, S I; Ziskin, M C

    2001-09-01

    Specific absorption rate (SAR) distributions in the vicinity of a thermocouple or air bubble in water and in the presence of hair or sweat duct in skin were calculated using analytical and two-dimensional impedance methods. The objects were exposed to uniform 42.25 GHz plane electromagnetic fields. Insertion of a 0.1-mm thermocouple or similarly sized air bubble into water produced a strong localized disturbance of the otherwise uniform SAR distribution. However, the average of SAR values immediately surrounding the thermocouple was close to the undisturbed uniform average SAR. This allows measuring the average SAR during exposure of both unbounded and bounded media using calibrated small thermocouples (up to 0.1 mm). The SAR distribution in the vicinity of a hair was qualitatively similar to that produced by an air bubble. The maximal value of SAR was more than three times higher than the overall average SAR value in the skin. Sweat ducts produced a smaller disturbance of the millimeter-wave (mm-wave) field.

  17. Electrochemical Analysis of the Electrodeposition of Platinum Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-Min; Cho, Sung-Woon; Kim, Jun-Hyun; Kim, Chang-Koo [Ajou University, Suwon (Korea, Republic of)

    2015-10-15

    A bath for electrodeposition of platinum nanoparticles on low-cost graphite substrates was developed to attach nanoparticles directly onto a substrate, and electrochemical characteristics of the electrodeposition of platinum nanoparticles were investigated. The reaction mechanism was examined by the analysis of polarization behavior. Cyclic voltammetry measurements revealed that the electrodeposition of platinum nanoparticles was limited by mass transfer. The chronoamperometric study showed an instantaneous nucleation mechanism during the electrodeposition of platinum nanoparticles on graphite. Because graphite is much cheaper than other carbon-based substrates, the electrodeposition of platinum nanoparticles on the graphite is expected to have useful applications.

  18. Outpatient desensitization in selected patients with platinum hypersensitivity reactions.

    Science.gov (United States)

    O'Malley, David M; Vetter, Monica Hagan; Cohn, David E; Khan, Ambar; Hays, John L

    2017-06-01

    Platinum-based chemotherapies are a standard treatment for both initial and recurrent gynecologic cancers. Given this widespread use, it is important to be aware of the features of platinum hypersensitivity reactions and the subsequent treatment of these reactions. There is also increasing interest in the development of desensitization protocols to allow patients with a history of platinum hypersensitivity to receive further platinum based therapy. In this review, we describe the management of platinum hypersensitivity reactions and the desensitization protocols utilized at our institution. We also describe the clinical categorizations utilized to triage patients to appropriate desensitization protocols. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Energy Harvesting Thermoelectric Generators Manufactured Using the Complementary Metal Oxide Semiconductor Process

    Directory of Open Access Journals (Sweden)

    Wen-Jung Tsai

    2013-02-01

    Full Text Available This paper presents the fabrication and characterization of energy harvesting thermoelectric micro generators using the commercial complementary metal oxide semiconductor (CMOS process. The micro generator consists of 33 thermocouples in series. Thermocouple materials are p-type and n-type polysilicon since they have a large Seebeck coefficient difference. The output power of the micro generator depends on the temperature difference in the hot and cold parts of the thermocouples. In order to increase this temperature difference, the hot part of the thermocouples is suspended to reduce heat-sinking. The micro generator needs a post-CMOS process to release the suspended structures of hot part, which the post-process includes an anisotropic dry etching to etch the sacrificial oxide layer and an isotropic dry etching to remove the silicon substrate. Experiments show that the output power of the micro generator is 9.4 mW at a temperature difference of 15 K.

  20. Energy harvesting thermoelectric generators manufactured using the complementary metal oxide semiconductor process.

    Science.gov (United States)

    Yang, Ming-Zhi; Wu, Chyan-Chyi; Dai, Ching-Liang; Tsai, Wen-Jung

    2013-02-08

    This paper presents the fabrication and characterization of energy harvesting thermoelectric micro generators using the commercial complementary metal oxide semiconductor (CMOS) process. The micro generator consists of 33 thermocouples in series. Thermocouple materials are p-type and n-type polysilicon since they have a large Seebeck coefficient difference. The output power of the micro generator depends on the temperature difference in the hot and cold parts of the thermocouples. In order to increase this temperature difference, the hot part of the thermocouples is suspended to reduce heat-sinking. The micro generator needs a post-CMOS process to release the suspended structures of hot part, which the post-process includes an anisotropic dry etching to etch the sacrificial oxide layer and an isotropic dry etching to remove the silicon substrate. Experiments show that the output power of the micro generator is 9.4 mW at a temperature difference of 15 K.

  1. An ion-exchange method for selective separation of palladium, platinum and rhodium from solutions obtained by leaching automotive catalytic converters.

    Science.gov (United States)

    Gaita, R; Al-Bazi, S J

    1995-02-01

    An ion-exchange method has been developed for the separation of palladium, platinum and rhodium from a solution that is highly acidic and contains a considerable amount of lead, aluminum, iron and cerium, obtained by leaching a used honeycomb type automotive catalytic converter. A column of Amberlite IRA-93 anion-exchange resin was found appropriate to recover platinum metals from the pregnant solution. Selective stripping of these metals from the resin was achieved by eluting rhodium first with 6.0M hydrochloric acid, then palladium with a 1% ammonia solution at ambient temperature, and platinum with 5% of the reagent at elevated temperatures. Optimum conditions for leaching these metals from the catalyst were 5.0M hydrochloric acid and 0.4M sodium chlorate at 70 degrees C. This method can be applied to both analytical as well as large scale operations. It is simple, economical, and relatively safe for human exposure and the environment.

  2. Bioleaching of metal ions from low grade sulphide ore: Process ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-05-10

    May 10, 2010 ... copper, gold, silver, platinum, chromium, iron, lead and zinc in various ... metal compounds into their water-soluble forms and are biocatalysts of this .... whose column elements represent the low, medium and high levels.

  3. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX

    2011-08-09

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

  4. Anticancer platinum (IV) prodrugs with novel modes of activity.

    Science.gov (United States)

    Chin, Chee Fei; Wong, Daniel Yuan Qiang; Jothibasu, Ramasamy; Ang, Wee Han

    2011-01-01

    Over the past four decades, the search for improved platinum drugs based on the classical platinum (II)-diam(m)ine pharmacophore has yielded only a handful of successful candidates. New methodologies centred on platinum (IV) complexes, with better stability and expanded coordination spheres, offer the possibility of overcoming limitations inherent to platinum (II) drugs. In this review, novel strategies of targeting and killing cancer cells using platinum (IV) constructs are discussed. These approaches exploit the unique electrochemical characteristics and structural attributes of platinum (IV) complexes as a means of developing anticancer prodrugs that can target and selectively destroy cancer cells. Anticancer platinum (IV) prodrugs represent promising new strategies as targeted chemotherapeutic agents in the ongoing battle against cancer.

  5. The Dynamics of Platinum Precipitation in an Ion Exchange Membrane

    CERN Document Server

    Burlatsky, S F; Atrazhev, V V; Dmitriev, D V; Kuzminyh, N Y; Erikhman, N S

    2013-01-01

    Microscopy of polymer electrolyte membranes that have undergone operation under fuel cell conditions, have revealed a well defined band of platinum in the membrane. Here, we propose a physics based model that captures the mechanism of platinum precipitation in the polymer electrolyte membrane. While platinum is observed throughout the membrane, the preferential growth of platinum at the band of platinum is dependent on the electrochemical potential distribution in the membrane. In this paper, the location of the platinum band is calculated as a function of the gas concentration at the cathode and anode, gas diffusion coefficients and solubility constants of the gases in the membrane, which are functions of relative humidity. Under H2/N2 conditions the platinum band is located near the cathode-membrane interface, as the oxygen concentration in the cathode gas stream increases and/or the hydrogen concentration in the anode gas stream decreases, the band moves towards the anode. The model developed in this paper...

  6. Search for and identification of gaseous noble metal emissions from catalytic converters. Quantitative and statistic screening of platinum metal aerosols emitted by automotive catalytic converters; Suche und Identifizierung von gasfoermigen katalysatorbuertigen Edelmetallemissionen (VPT 06). Quantitative und statistische Reihenuntersuchungen ueber emittierte Platinmetallaerosole aus Automobilkatalysatoren (VPT 08)

    Energy Technology Data Exchange (ETDEWEB)

    Artelt, S. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung, Hannover (Germany)

    1997-12-31

    The aim of these two projects was to determine whether platinum is contained in catalysed automobile exhaust fumes and in what quantities it is emitted. A further task was to determine the particle size and particle size distribution of emitted particles. For this purpose an engine test stand was set up at the Fraunhofer Institute for Toxicology and Aerosol Research and two different sampling techniques were developed. [Deutsch] Im Rahmen dieser beiden Vorhaben sollte untersucht werden, ob Platin im katalysierten Automobilabgas vorhanden ist und in welcher Menge es emittiert wird. Weiterhin sollte die Partikelgroesse der emittierten Partikel und ihre Verteilung bestimmt werden. Im Fraunhofer-Institut fuer Toxikologie und Aerosolforschung wurde dazu ein Motorstand aufgebaut und zwei unterschiedliche Probenahmetechniken entwickelt. (orig.)

  7. Platinum compounds with anti-tumour activity

    NARCIS (Netherlands)

    Plooy, A.C.M.; Lohman, P.H.M.

    1980-01-01

    Ten platinum (Pt) coordination complexes with different ligands, comprising both Pt(II) and Pt(IV) complexes of which the cis-compounds all possessed at least some anti-tumour activity and the trans-compounds were inactive, were tested as to their effect on cell survival and the induction and repair

  8. On the enzymatic formation of platinum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Govender, Y.; Riddin, T. L. [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa); Gericke, M. [MINTEK (South Africa); Whiteley, C. G., E-mail: C.Whiteley@ru.ac.z [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa)

    2010-01-15

    A dimeric hydrogenase enzyme (44.5 and 39.4 kDa sub units) was isolated in a 39.5% yield from the fungus Fusarium oxysporum and purified 4.64-fold by ion exchange chromatography on Sephacryl S-200. Characterisation of the enzyme afforded pH and temperature optima of 7.5 and 38 {sup o}C, respectively, a half-life stability of 36 min and a V{sub max} and K{sub m} of 3.57 nmol min{sup -1} mL{sup -1} and 2.25 mM, respectively. This enzyme was inhibited (non-competitively) by hydrogen hexachloroplatinic acid (H{sub 2}PtCl{sub 6}) at 1 or 2 mM with a K{sub i} value of 118 {mu}M. Incubation of the platinum salt with the pure enzyme under an atmosphere of hydrogen and optimum enzyme conditions (pH 7.5, 38 {sup o}C) afforded <10% bioreduction after 8 h while at conditions suitable for platinum nanoparticle formation (pH 9, 65 {sup o}C) over 90% reduction took place after the same length of time. Cell-free extract from the fungal isolates produced nearly 90% bioreduction of the platinum salt under both pH and temperature conditions. The bioreduction of the platinum salt by a hydrogenase enzyme takes place by a passive process and not an active one as previously understood.

  9. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported.

  10. Targeting Platinum Compounds: synthesis and biological activity

    OpenAIRE

    VAN ZUTPHEN, Steven

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of novel (solid-phase) synthetic methods and to the discovery of several compounds with promising biological properties.

  11. Targeting Platinum Compounds : synthesis and biological activity

    NARCIS (Netherlands)

    Zutphen, Steven van

    2005-01-01

    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of

  12. Skin Sensitizing Potency of Halogenated Platinum Salts.

    Science.gov (United States)

    The relationship between occupational exposure to halogenated platinum (Pt) salts and Pt-specific allergic sensitization is well-established. Although human case reports and clinical studies demonstrate that Pt salts are potent skin sensitizers, no studies have been published tha...

  13. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de

    2000-01-01

    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported. Is

  14. Very High Output Thermoelectric Devices Based on ITO Nanocomposites

    Science.gov (United States)

    Fralick, Gustave; Gregory, Otto J.

    2009-01-01

    A material having useful thermoelectric properties was synthesized by combining indium-tin-oxide (ITO) with a NiCoCrAlY alloy/alumina cermet. This material had a very large Seebeck coefficient with electromotive-force-versustemperature behavior that is considered to be excellent with respect to utility in thermocouples and other thermoelectric devices. When deposited in thin-film form, ceramic thermocouples offer advantages over precious-metal (based, variously, on platinum or rhodium) thermocouples that are typically used in gas turbines. Ceramic thermocouples exhibit high melting temperatures, chemical stability at high temperatures, and little or no electromigration. Oxide ceramics also resist oxidation better than metal thermocouples, cost substantially less than precious-metal thermocouples, and, unlike precious-metal thermocouples, do not exert catalytic effects.

  15. Sorption recovery of platinum (II, IV in presence of copper (II and zinc (II from chloride solutions

    Directory of Open Access Journals (Sweden)

    Kononova Olga N.

    2015-01-01

    Full Text Available The sorption preconcentration of platinum (II, IV ions was investigated in presence of accompanying copper (II and zinc (II ions from chloride solutions on the new ion exchangers CYBBER (Russia, previously unexplored. The initial concentrations of platinum and accompanying ions were 0.25 mmol L-1 and 2.0 mmol L-1, respectively, and the acidity of medium was 0.001 - 4.0 mol L-1. It was shown that the resins investigated - strong and weak basic anion exchangers as well as chelate ion exchangers - possess good sorption and kinetic properties. The simultaneous sorption of investigated ions results in the complete recovery of platinum, while the non-ferrous metal ions are sorbed at less than 20%. Followed by the selective elution of platinum by thiourea (80 g L-1 solution in 0.3 M H2SO4, the quantitative isolation of platinum was achieved (more than 90%. Therefore, the studied ion exchangers can be recommended for recovery and separation of Pt(II,IV, Cu(II and Zn(II ions.

  16. The role of macrocyclic compounds in the extraction and possible separation of platinum and rhodium from chloride solutions

    Science.gov (United States)

    Jyothi, Rajesh Kumar; Lee, Jin-Young

    2016-06-01

    Macrocyclic compounds (crown ethers), specifically 18-crown-6 (18-C-6), benzo-15-crown-5 (B-15-C-5), di-benzo-18-crown-6 (DB-18-C-6) and di-cyclohexano-18-crown-6 (DC-18C-6), are used as extractants as well as synergists with amine-group extractants. Platinum and rhodium belong to platinum-group metals (PGMs) and have very similar ionic radii and similar properties. The separation of PGMs is most useful for the preparation of functional materials. Macrocyclic compounds are tested for platinum and rhodium separation and are found to achieve marginal separation. Amines (used as extractants) are paired with macrocyclic compounds (used as synergists), and the separation factor between platinum and rhodium is increased with synergistic enhancement from a chloride solution. The present study discusses extraction chemistry, separation factors and the synergy between platinum and rhodium from chloride solutions. To ensure accurate data, the aqueous samples in this study are analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES).

  17. Preparation of Dispersed Platinum Nanoparticles on a Carbon Nanostructured Surface Using Supercritical Fluid Chemical Deposition

    Directory of Open Access Journals (Sweden)

    Mineo Hiramatsu

    2010-03-01

    Full Text Available We have developed a method of forming platinum (Pt nanoparticles using a metal organic chemical fluid deposition (MOCFD process employing a supercritical fluid (SCF, and have demonstrated the synthesis of dispersed Pt nanoparticles on the surfaces of carbon nanowalls (CNWs, two-dimensional carbon nanostructures, and carbon nanotubes (CNTs. By using SCF-MOCFD with supercritical carbon dioxide as a solvent of metal-organic compounds, highly dispersed Pt nanoparticles of 2 nm diameter were deposited on the entire surface of CNWs and CNTs. The SCF-MOCFD process proved to be effective for the synthesis of Pt nanoparticles on the entire surface of intricate carbon nanostructures with narrow interspaces.

  18. Carbon monoxide tolerant platinum electrocatalysts on niobium doped titania and carbon nanotube composite supports

    Science.gov (United States)

    Rigdon, William A.; Huang, Xinyu

    2014-12-01

    In the anode of electrochemical cells operating at low temperature, the hydrogen oxidation reaction is susceptible to poisoning from carbon monoxide (CO) which strongly adsorbs on platinum (Pt) catalysts and increases activation overpotential. Adsorbed CO is removed by oxidative processes such as electrochemical stripping, though cleaning can also cause corrosion. One approach to improve the tolerance of Pt is through alloying with less-noble metals, but the durability of alloyed electrocatalysts is a critical concern. Without sacrificing stability, tolerance can be improved by careful design of the support composition using metal oxides. The bifunctional mechanism is promoted at junctions of the catalyst and metal oxides used in the support. Stable metal oxides can also form strong interactions with catalysts, as is the case for platinum on titania (TiOx). In this study, niobium (Nb) serves as an electron donor dopant in titania. The transition metal oxides are joined to functionalized multi-wall carbon nanotube (CNT) supports in order to synthesize composite supports. Pt is then deposited to form electrocatalysts which are characterized before fabrication into anodes for tests as an electrochemical hydrogen pump. Comparisons are made between the control from Pt-CNT to Pt-TiOx-CNT and Pt-Ti0.9Nb0.1Ox-CNT in order to demonstrate advantages.

  19. The metal to metal interface and its effect on adhesion and friction

    Science.gov (United States)

    Buckley, D. H.

    1976-01-01

    The paper considers the interface between two bulk metals and the effect of this interface on adhesive bonding, resistance to tangential displacements, friction and the interfacial transport from one surface to another. Using Auger emission spectroscopy, field ion microscopy, and low energy electron diffraction techniques, the influence of surface orientation, lattice registry, crystal lattice structure and defects, metal surface chemistry and alloying on the characteristics of the interface was studied for noble, platinum, transition, and Group 4B metals. With dissimilar metals in contact, epitaxial transfer of the cohesively weaker to the cohesively stronger metal has been observed. Surface chemical activity of the noble and platinum metals is shown to affect interfacial behavior as does a valence bonding in the transition metals, and the degree of metallic nature in the Group 4B elements. Alloying elements, e.g., Si and Fe, can alter interfacial behavior by segregation to the surface of metals or by altering bulk properties such as crystal transformation kinetics.

  20. Bis-NHC chelate complexes of nickel(0) and platinum(0).

    Science.gov (United States)

    Brendel, Matthias; Braun, Carolin; Rominger, Frank; Hofmann, Peter

    2014-08-11

    For a long time d(10)-ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ-donating ligands leading to electron-rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis-NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5-cyclooctadiene)nickel(0) and -platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal-planar bis-NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C-C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond-activation chemistry and catalysis.

  1. Multistep electrochemical deposition of hierarchical platinum alloy counter electrodes for dye-sensitized solar cells

    Science.gov (United States)

    Zhang, Junjun; Ma, Mingming; Tang, Qunwei; Yu, Liangmin

    2016-01-01

    The preferred platinum counter electrode (CE) has been a burden for commercialization of dye-sensitized solar cell (DSSC) due to high expense and chemical corrosion by liquid electrolyte. In the current study, we have successfully realized the multistep deposition of platinum alloy CEs including PtNi, PtFe, and PtCo for liquid-junction DSSC applications. The preliminary results demonstrate that the enhanced electrochemical activities are attributable to high charge-transfer ability and matching work functions of the PtM (M = Ni, Fe, Co) alloy CEs to redox potential of I-/I3- electrolyte. The resultant DSSCs yield impressive power conversion efficiencies of 8.65%, 7.48%, and 7.08% with PtNi, PtFe, and PtCo CEs, respectively. On behalf of the competitive reactions between transition metals with liquid electrolyte, the PtM alloy CEs display enhanced long-term stability.

  2. Highly stable water-soluble platinum nanoparticles stabilized by hydrophilic N-heterocyclic carbenes.

    Science.gov (United States)

    Baquero, Edwin A; Tricard, Simon; Flores, Juan Carlos; de Jesús, Ernesto; Chaudret, Bruno

    2014-11-24

    Controlling the synthesis of stable metal nanoparticles in water is a current challenge in nanochemistry. The strategy presented herein uses sulfonated N-heterocyclic carbene (NHC) ligands to stabilize platinum nanoparticles (PtNPs) in water, under air, for an indefinite time period. The particles were prepared by thermal decomposition of a preformed molecular Pt complex containing the NHC ligand and were then purified by dialysis and characterized by TEM, high-resolution TEM, and spectroscopic techniques. Solid-state NMR studies showed coordination of the carbene ligands to the nanoparticle surface and allowed the determination of a (13)C-(195)Pt coupling constant for the first time in a nanosystem (940 Hz). Additionally, in one case a novel structure was formed in which platinum(II) NHC complexes form a second coordination sphere around the nanoparticle.

  3. Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases.

    Science.gov (United States)

    Fu, Wei; Li, Xin-Hao; Bao, Hong-Liang; Wang, Kai-Xue; Wei, Xiao; Cai, Yi-Yu; Chen, Jie-Sheng

    2013-01-01

    The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance. It is revealed that in the Pt-loaded SAPO-CHA catalyst, there exists a remarkable synergistic effect between the Brønsted acid sites and the Pt nanoparticles, the former helping to adsorb and activate the hydrocarbon molecules for NO reduction during the catalytic process. The thermal stability of SAPO-CHA also makes the composite catalyst stable and reusable without activity decay.

  4. Quasi-homogeneous hydrogenation with platinum and palladium nanoparticles stabilized by dendritic core-multishell architectures.

    Science.gov (United States)

    Schwarze, Michael; Keilitz, Juliane; Nowag, Sabrina; Parapat, Riny Y; Haag, Rainer; Schomäcker, Reinhard

    2011-05-17

    Platinum and palladium nanoparticles, supported and stabilized by polymeric core-shell architectures, proved to be active catalysts for hydrogenation reactions. Here, two different reactions were used as probes to investigate the influence of the polymeric support: the hydrogenation of α-methyl styrene (AMS) to cumene and the partial hydrogenation of 1,5-cyclooctadiene (COD). We found that the stability of the nanoparticles and the rate of reaction are higher in the presence of a hydrophobic octadecyl shell within a three-shell polymer system. The kinetic study of AMS hydrogenation showed much higher activities for palladium nanoparticles than for platinum nanoparticles, and the obtained results (e.g., 35 kJ/mol for the activation energy) are of the same order of magnitude as reported earlier for palladium supported on alumina. A methanol/n-heptane biphasic mixture was tested for catalyst recycling and allowed for highly efficient catalyst separation with very low metal leaching.

  5. Surface features and catalytic performance of platinum/alumina catalysts in slurry-phase hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Ortiz, M.A.; Gonzalez-Marcos, M.P.; Arnaiz-Aguilar, S.; Gonzalez-Marcos, J.A.; Gonzalez-Velasco, J.R. (Univ. del Pais Vasco/Euskal Hirrika Unibertsitatea, Bilbao (Spain). Dept. de Ingenierlla Quimica)

    1993-11-01

    Several platinum catalysts supported on three commercial [gamma]-aluminas were prepared by impregnation and anionic exchange using aqueous solutions of H[sub 2]PtCl[sub 6]. A number of methods were used to characterize the precursors as well as the final catalysts, including TGA, TPR, and hydrogen chemisorption at 298 K. TPR measurements showed two reduction peaks for the catalysts: the first one corresponding to reduction of the metal precursor to platinum and the second one associated to formation of a surface complex, Pt-Al[sub 2]O[sub 3[minus]x], With partial reduction of the support. The activity of the different catalysts was tested in the slurry-phase hydrogenation of benzene. The results obtained in the activity measurements have been correlated to the characteristics of the catalysts.

  6. Concurrent chemoradiotherapy comparison of taxanes and platinum versus 5-fluorouracil and platinum in nasopharyngeal carcinoma treatment

    Institute of Scientific and Technical Information of China (English)

    Chen Xichuang; Hong Yuan; Feng Jinhua; Ye Jianlin; Zheng Panpan; Guan Xiyin; You Xiaohong

    2014-01-01

    Background Nasopharyngeal carcinoma (NPC) is a squamous-cell carcinoma especially prevailing among the natives of southern China.The regimen of concurrent chemoradiotherapy (CCRT) that include platinum and 5-fluorouracil (5-FU)is considered to be the standard treatment for NPC.However,its clinical use is limited by its toxicity.Our purpose was to evaluate the efficacy and safety of the regimen of CCRT with taxanes and platinum versus the regimen of CCRT with 5-FU and platinum in NPC treatment.Methods Medline,the Cochrane library,and the Chinese medical literature database were searched for eligible studies.Meta-analysis was performed using Review Manager (Version 5.2).Results Six random controlled trials (RCTs) including 514 patients met our criteria.Meta-analysis showed that the regimen of CCRT with taxanes and platinum had an improved significant difference in complete remission (CR) and less incidence rate in adverse reactions such as gastrointestinal impairment grades Ⅲll-Ⅳ,liver and kidney impairment grades Ⅰ-Ⅱ,and radiodermatitis grades Ⅲ-Ⅳ versus the conventional regimen of CCRT with 5-FU and platinum,while the long-term effectiveness rate of overall survival,Iocoregional failure-free survival,or distant metastasis failure-free survival between the two groups was therapeutic equivalence.Conclusions The regimen of CCRT with taxanes and platinum in NPC therapy may be more efficient and safe compared to the conventional modality of 5-FU and platinum in CCRT.However,we need more high-quality studies of multi-center and randomized double-blind clinical trials to further compare,analyze,and confirm the findings.

  7. New platinum(II complexes with benzothiazole ligands

    Directory of Open Access Journals (Sweden)

    José A. Carmona-Negrón

    2016-03-01

    Full Text Available Four new platinum(II complexes, namely tetraethylammonium tribromido(2-methyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C8H7NS] (1, tetraethylammonium tribromido(6-methoxy-2-methyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C9H9NOS] (2, tetraethylammonium tribromido(2,5,6-trimethyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C10H11NS] (3, and tetraethylammonium tribromido(2-methyl-5-nitro-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C8H6N2O2S] (4, have been synthesized and structurally characterized by single-crystal X-ray diffraction techniques. These species are precursors of compounds with potential application in cancer chemotherapy. All four platinum(II complexes adopt the expected square-planar coordination geometry, and the benzothiazole ligand is engaged in bonding to the metal atom through the imine N atom (Pt—N. The Pt—N bond lengths are normal: 2.035 (5, 2.025 (4, 2.027 (5 and 2.041 (4 Å for complexes 1, 2, 3 and 4, respectively. The benzothiazole ligands are positioned out of the square plane, with dihedral angles ranging from 76.4 (4 to 88.1 (4°. The NEt4 cation in 3 is disordered with 0.57/0.43 occupancies.

  8. Formic acid oxidation at platinum-bismuth catalysts

    Directory of Open Access Journals (Sweden)

    Popović Ksenija Đ.

    2015-01-01

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

  9. Cytotoxic properties of a new organometallic platinum(II) complex and its gold(I) heterobimetallic derivatives.

    Science.gov (United States)

    Serratrice, Maria; Maiore, Laura; Zucca, Antonio; Stoccoro, Sergio; Landini, Ida; Mini, Enrico; Massai, Lara; Ferraro, Giarita; Merlino, Antonello; Messori, Luigi; Cinellu, Maria Agostina

    2016-01-14

    A novel platinum(ii) organometallic complex, [Pt(pbi)(Me)(DMSO)], bearing the 2-(2'-pyridyl)-benzimidazole (pbiH) ligand, was synthesized and fully characterized. Interestingly, the reaction of this organometallic platinum(ii) complex with two distinct gold(i) phosphane compounds afforded the corresponding heterobimetallic derivatives with the pbi ligand bridging the two metal centers. The antiproliferative properties in vitro of [Pt(pbi)(Me)(DMSO)] and its gold(i) derivatives as well as those of the known coordination platinum(ii) and palladium(ii) complexes with the same ligand, of the general formula [MCl2(pbiH)], were comparatively evaluated against A2780 cancer cells, either sensitive or resistant to cisplatin. A superior biological activity of the organometallic compound clearly emerged compared to the corresponding platinum(ii) complex; the antiproliferative effects are further enhanced upon attaching the gold(i) triphenylphosphine moiety to the organometallic Pt compound. Remarkably, these novel metal species are able to overcome nearly complete resistance to cisplatin. Significant mechanistic insight into the study compounds was gained after investigating their reactions with a few representative biomolecules by electrospray mass spectrometry and X-ray crystallography. The obtained results are comprehensively discussed.

  10. Practical system for the direct measurement of magneto-caloric effect by micro-thermocouples.

    Science.gov (United States)

    Kamarád, J; Kaštil, J; Arnold, Z

    2012-08-01

    A system for direct measurements of the magneto-caloric effect (MCE) exploits a rapid transport of a sample into or from magnetic field in permanent Halbach-type (1 T) or superconducting (4.7 T) magnets. Time dependence of induced changes of the sample temperature, ΔT(t), is detected directly by the differential Cu-Constantan-Cu micro-thermocouples with time steps of 300 ms. A sample placed inside an evacuated simple LN(2) cryostat is either totally isolated (adiabatic conditions) or partly connected with the copper sample holder (non-adiabatic conditions). The last arrangement (a model of the Brayton cycle) is used to simulate an application of MCE in refrigeration techniques. The relations describing ΔT(t) that allow an analysis of MCE of the studied materials are based on the general cooling law. The effect of the first-order magnetic transition on MCE of selected sample is also demonstrated by non-standard ΔT(t) curves measured in the last mentioned experimental arrangements.

  11. Comparison of two surface temperature measurement using thermocouples and infrared camera

    Directory of Open Access Journals (Sweden)

    Michalski Dariusz

    2017-01-01

    Full Text Available This paper compares two methods applied to measure surface temperatures at an experimental setup designed to analyse flow boiling heat transfer. The temperature measurements were performed in two parallel rectangular minichannels, both 1.7 mm deep, 16 mm wide and 180 mm long. The heating element for the fluid flowing in each minichannel was a thin foil made of Haynes-230. The two measurement methods employed to determine the surface temperature of the foil were: the contact method, which involved mounting thermocouples at several points in one minichannel, and the contactless method to study the other minichannel, where the results were provided with an infrared camera. Calculations were necessary to compare the temperature results. Two sets of measurement data obtained for different values of the heat flux were analysed using the basic statistical methods, the method error and the method accuracy. The experimental error and the method accuracy were taken into account. The comparative analysis showed that although the values and distributions of the surface temperatures obtained with the two methods were similar but both methods had certain limitations.

  12. Remarkable NO oxidation on single supported platinum atoms.

    Science.gov (United States)

    Narula, Chaitanya K; Allard, Lawrence F; Stocks, G M; Moses-DeBusk, Melanie

    2014-11-28

    Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-Al2O3 supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate our theoretical study, we evaluated single θ-Al2O3 supported platinum atoms and found them to exhibit remarkable NO oxidation activity. A comparison of turnover frequencies (TOF) of single supported Pt atoms with those of platinum particles for NO oxidation shows that single supported Pt atoms are as active as fully formed platinum particles. Thus, the overall picture of NO oxidation on supported Pt is that NO oxidation activity decreases with decreasing Pt particle size but accelerates when Pt is present only as single atoms.

  13. Correct utilization of thermocouple compensation conductor%热电偶补偿导线的正确使用

    Institute of Scientific and Technical Information of China (English)

    张丽

    2012-01-01

    The thesis introduces the utilization principles of compensation conductor, analyzes the impact of operation errors upon thermocouple temperature measuring results, and puts forward correct compensation conduction utilization methods, with a view to thermocouple temperature measuring error influencing other thermal controlling aspects.%对补偿导线的使用原理进行了介绍,阐述了操作错误对热电偶温度测量结果的影响,并提出补偿导线的正确使用方法,以避免热电偶的测温结果出现较大误差影响热控工作其他环节。

  14. Examining the surfaces in used platinum catalysts

    Directory of Open Access Journals (Sweden)

    Trumić B.

    2009-01-01

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

  15. Selective laser extraction of the Pt group metals

    Energy Technology Data Exchange (ETDEWEB)

    Fadeeva, S.; Krynetsky, B.; Prokhorov, A.; Zhidkov, A. [General Physics Institute, Russian Academy of Science, Moscow (Russian Federation)

    1995-11-15

    The interest to the platinum-group metals extraction from solutions, especially industry waste, is stimulated by their extraordinary chemical inert. The traditional chemical methods of the extraction are uneffective. Have been investigated process of the extraction of metal Pt-group from acid solutions. Discussed processes reduction of noble metals by resonance laser action.

  16. Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

    DEFF Research Database (Denmark)

    Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian

    2012-01-01

    Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first...

  17. External Attachment of Titanium Sheathed Thermocouples to Zirconium Nuclear Fuel Rods For The Loss-Of-Fluid-Test (LOFT) Reactor

    Science.gov (United States)

    Welty, Richard K.

    1980-10-01

    The Exxon Nuclear Company, Inc. acting as a Subcontractor to EG&G Idaho Inc.3 Idaho National Engineering Laboratory, Idaho Falls, Idaho, has developed a welding process to attach titanium sheathed thermocouples to the outside of the zircaloy clad fuel rods. The fuel rods and thermocouples are used to test simulated loss-of-coolant-accident (LOCA) conditions in a pressurized water reactor (LOFT Reactor, Idaho National Laboratory). The design goals were to (1) reliably attach thermocouples to the zircaloy fuel rods, (2) achieve or exceed a life expectancy of 6,000 hours of reactor operation in a borated water environment of 316°C at 2260 psi, (3) provide and sustain repeatable physical and metallurgical properties in the instrumented rods subjected to transient temperatures up to 1538°C with blowdown, shock, loading, and fast quench. A laser beam was selected as the optimum welding process because of the extremely high energy input per unit volume that can be achieved allowing local fusion of a small area irrespective of the difference in material thickness to be joined. A commercial pulsed laser and energy control system was installed along with specialized welding fixtures. Laser room facility requirements and tolerances were established. Performance qualifications and detailed welding procedures were also developed. Product performance tests were conducted to assure that engineering design requirements could be met on a production basis. Irradiation tests showed no degradation of thermocouples or weld structure. Fast thermal cycle and heater rod blowdown reflood tests were made to subject the weldments to high temperatures, high pressure steam, and fast water quench cycles. From the behavior of these tests, it was concluded that the attachment welds would survive a series of reactor safety tests.

  18. Platinum Acetylide Two-Photon Chromophores (Preprint)

    Science.gov (United States)

    2007-04-01

    the higher energy range that lead to its photodegradation . Secondly, because there is a quadratic dependence of two-photon absorption (2PA) on the...to either an electron donating amino- fluorenyl or electron withdrawing benzothiazolyl-fluorene that are themselves known as two-photon absorbing dyes ...groups in place of phenyl groups have shown a doubling of the intrinsic cr2value at 740 nm.40,41In this paper we describe novel platinum dyes that

  19. Redeposition of electrochemically dissolved platinum as nanoparticles on carbon

    DEFF Research Database (Denmark)

    Norgaard, C. F.; Stamatin, S. N.; Skou, E. M.

    2014-01-01

    Electrochemical dissolution of platinum has been proposed by several research groups as an environmentally friendly way to recover platinum from catalytic structures such as fuel cell electrodes. For the case of electrochemical dissolution of platinum in hydrochloric acid electrolyte, the present...... on carbon was then identified, quantified, and the particle size evaluated by powder X-ray diffraction, thermogravimetric analysis and cyclic voltammetry. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved....

  20. Platinum germanium ordering in UPtGe

    Science.gov (United States)

    Hoffmann, Rolf-Dieter; Pöttgen, Rainer; Lander, Gerry H.; Rebizant, Jean

    2001-09-01

    The non-centrosymmetric structure of UPtGe was investigated by X-ray diffraction on both powders and single crystals: EuAuGe type, Imm2, a=432.86(5), b=718.81(8), c=751.66(9) pm, wR2=0.0738 for 399 F2 values and 22 variables. The platinum and germanium atoms form two-dimensional layers of puckered Pt 3Ge 3 hexagons with short PtGe intralayer distances of 252 and 253 pm. These condensed two-dimensionally infinite nets are interconnected to each other via weak PtPt contacts with bond distances of 300 pm. The two crystallographically independent uranium atoms are situated above and below the six-membered platinum-germanium rings. The U1 atoms have six closer germanium neighbors while the U2 atoms have six closer platinum neighbors. The group-subgroup relation with the KHg 2 type structure is presented.

  1. Síntese e caracterização de novos complexos de platina (II com ligantes derivados do furano e nitrofurano Synthesis and characterization of new platinum (II complexes containing furan and nitrofuran derived ligands

    Directory of Open Access Journals (Sweden)

    Wendell Guerra

    2005-10-01

    Full Text Available Platinum (II complexes, for example, cisplatin and carboplatin, have been used as chemotherapeutic agents for the treatment of various types of cancer. Several other complexes of this metallic ion are also under clinical evaluation. This work describes the synthesis of five new platinum (II complexes having furan and 5-nitrofuran derivatives and chloride as ligands. The compounds were characterized by NMR, IR and elemental analysis.

  2. 热电偶测温系统设计%Design of thermocouple system for temperature measurement

    Institute of Scientific and Technical Information of China (English)

    李彦芳

    2013-01-01

    用热电偶测量温度是航空温度测量中应用最广泛的一种方式,常用来测量高温气流及高速气流.提出了一种可以应用于管道内流体测量的热电偶测温系统的设计方法:以热电偶作为感温元件,配合变换器实现准确可靠的温度测量,输出的电压信号与对应温度成线性关系.通过设计实例及试验,验证了系统的精度性能,实现了预期的设计目标.%Thermocouple is widely used in aviation field for temperature measurement,often used to measure air flow of high temperature or high speed.Proposed a thermocouple system for piping fluid:thermocouple as temperature sensing element,with the transducer to achieve accurate and reliable measurement result,the output voltage signal is linear with the corresponding temperature.By design examples and test results,to verify the accuracy of the system performance,to achieve the expected goals of design.

  3. New fixed-point mini-cell to investigate thermocouple drift in a high-temperature environment under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Laurie, M.; Vlahovic, L.; Rondinella, V.V. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe, (Germany); Sadli, M.; Failleau, G. [Laboratoire Commun de Metrologie, LNE-Cnam, Saint-Denis, (France); Fuetterer, M.; Lapetite, J.M. [European Commission, Joint Research Centre, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten, (Netherlands); Fourrez, S. [Thermocoax, 8 rue du pre neuf, F-61100 St Georges des Groseillers, (France)

    2015-07-01

    Temperature measurements in the nuclear field require a high degree of reliability and accuracy. Despite their sheathed form, thermocouples subjected to nuclear radiations undergo changes due to radiation damage and transmutation that lead to significant EMF drift during long-term fuel irradiation experiment. For the purpose of a High Temperature Reactor fuel irradiation to take place in the High Flux Reactor Petten, a dedicated fixed-point cell was jointly developed by LNE-Cnam and JRC-IET. The developed cell to be housed in the irradiation rig was tailor made to quantify the thermocouple drift during the irradiation (about two year duration) and withstand high temperature (in the range 950 deg. C - 1100 deg. C) in the presence of contaminated helium in a graphite environment. Considering the different levels of temperature achieved in the irradiation facility and the large palette of thermocouple types aimed at surveying the HTR fuel pebble during the qualification test both copper (1084.62 deg. C) and gold (1064.18 deg. C) fixed-point materials were considered. The aim of this paper is to first describe the fixed-point mini-cell designed to be embedded in the reactor rig and to discuss the preliminary results achieved during some out of pile tests as much as some robustness tests representative of the reactor scram scenarios. (authors)

  4. Preparation and Electrochemical Properties of Porous Platinum Electrode

    Institute of Scientific and Technical Information of China (English)

    HE Xin; CHEN Boxun; CHEN Qiao

    2012-01-01

    Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O2(g)/Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.

  5. Controlled synthesis of porous platinum nanostructures for catalytic applications.

    Science.gov (United States)

    Cao, Yanqin; Zhang, Junwei; Yang, Yong; Huang, Zhengren; Long, Nguyen Viet; Nogami, Masayuki

    2014-02-01

    Porous platinum, that has outstanding catalytic and electrical properties and superior resistant characteristics to corrosion, has been widely applied in chemical, petrochemical, pharmaceutical, electronic, and automotive industries. As the catalytic activity and selectivity depend on the size, shape and structure of nanomaterials, the strategies for controlling these factors of platinum nanomaterials to get excellent catalytic properties are discussed. Here, recent advances in the design and preparation of various porous platinum nanostructures are reviewed, including wet-chemical synthesis, electro-deposition, galvanic replacement reaction and de-alloying technology. The applications of various platinum nanostructures are also discussed, especially in fuel cells.

  6. Novel platinum(II) compounds with O,S bidentate ligands: synthesis, characterization, antiproliferative properties and biomolecular interactions.

    Science.gov (United States)

    Mügge, Carolin; Liu, Ruiqi; Görls, Helmar; Gabbiani, Chiara; Michelucci, Elena; Rüdiger, Nadine; Clement, Joachim H; Messori, Luigi; Weigand, Wolfgang

    2014-02-28

    Cisplatin and its analogues are first-line chemotherapeutic agents for the treatment of numerous human cancers. A major inconvenience in their clinical use is their strong tendency to link to sulfur compounds, especially in kidney, ultimately leading to severe nephrotoxicity. To overcome this drawback we prepared a variety of platinum complexes with sulfur ligands and analyzed their biological profiles. Here, a series of six platinum(II) compounds bearing a conserved O,S binding moiety have been synthesized and characterized as experimental anticancer agents. The six compounds differ in the nature of the O,S bidentate β-hydroxydithiocinnamic alkyl ester ligand where both the substituents on the aromatic ring and the length of the alkyl chain may be varied. The two remaining coordination positions at the square-planar platinum(II) center are occupied by a chloride ion and a DMSO molecule. These novel platinum compounds showed an acceptable solubility profile in mixed DMSO-buffer solutions and an appreciable stability at physiological pH as judged from analysis of their time-course UV-visible absorption spectra. Their anti-proliferative and pro-apoptotic activities were tested against the cisplatin-resistant lung cancer cell line A549. Assays revealed significant effects of the sample drugs at low concentrations (in the μmolar range); initial structure-activity-relationships are proposed. The activity of the apoptosis-promoting protein caspase 3/7 was determined; results proved that these novel platinum compounds, under the chosen experimental conditions, preferentially induce apoptosis over necrosis. Reactions with the model proteins cytochrome c, lysozyme and albumin were studied by ESI MS and ICP-OES to gain preliminary mechanistic information. The tested compounds turned out to metalate the mentioned proteins to a large extent. In view of the obtained results these novel platinum complexes qualify themselves as promising cytotoxic agents and merit, in our

  7. Domestic Production Issues in Chromium and Platinum-Group Metals

    Science.gov (United States)

    1988-09-01

    Protection Agency. OPA 87-005. Washington: Government Printing Office, May 1987. 16. Foley, Jeffrey Y. and James C. Barker . Chromite Deposits Along...Mining, Metallurgical, and Petroleum Engineers, 1976. 52. Stowe, Clive W. Evolution of Chromium Ore Fields. New York: Van Nostrand Reinhold Company

  8. The influence of reduction methods and conditions on the activity of alumina-supported platinum catalysts for the liquid phase hydrogenation of benzaldehyde in ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Arai, M.; Obata, A.; Nishiyama, Y. [Tohoku Univ., Sendai (Japan)

    1997-02-01

    The activities of supported metal catalysts depend on various preparation variables, including the method of reduction. A variety of reduction procedures can be applied to the preparation of supported metal catalysts. Previously, the authors used a solid-liquid reduction by sodium tetrahydroborate solution for preparing supported platinum catalysts. In this reduction, platinum precursors adsorbed on supports were brought into contact with the reducing solution. The alumina-supported platinum catalysts prepared in this way were found to display interesting activities in the liquid-phase hydrogenation of {alpha},{beta}-unsaturated aldehydes; they were highly selective to the formation of unsaturated alcohols. The selective hydrogenation of C=O bonds of {alpha},{beta}-unsaturated aldehydes is difficult to achieve with platinum catalysts without using some additives like tin and iron. The maximum temperature that the supported platinum catalysts went through was 110{degrees}C, required for the removal of water. This thermal history is a possible reason for the catalytic activity observed. Following those observations, in the present work, the authors have further examined the influence of reduction procedures by using hydrazine as well as sodium tetrahydroborate and different temperatures common during gas-phase reduction with hydrogen. The catalytic activity has been tested by the liquid-phase hydrogenation of benzaldehyde (BAL) in ethanol under mild conditions. 12 refs., 3 figs.

  9. How much platinum passes the placental barrier? Analysis of platinum applications in 21 patients with cervical cancer during pregnancy.

    Science.gov (United States)

    Köhler, Christhardt; Oppelt, Peter; Favero, Giovanni; Morgenstern, Bernd; Runnebaum, Ingo; Tsunoda, Audrey; Schmittel, Alexander; Schneider, Achim; Mueller, Michael; Marnitz, Simone

    2015-08-01

    Cervical cancer is the most common solid cancer diagnosed in pregnancy. Platinum is an active drug in the treatment of patients with cervical cancer. In the second and third trimesters, platinum is used to prevent cancer progression until fetal maturity is reached. However, knowledge about the transplacental passage of platinum is very limited. Between May 2008 and June 2014, platinum-based neoadjuvant chemotherapy was applied to 21 consecutive patients with cervical cancer diagnosed in their second trimester. At the time of delivery by cesarean delivery, synchronous samples from maternal blood, umbilical cord blood, and amniotic fluid were taken and analyzed for platinum concentrations. The mean week of gestation at cancer diagnosis was 17 (13-23). On average 3 (range, 2-4) cycles of chemotherapy were applied. Cesarean deliveries were carried out between 30.4 and 36.5 weeks of gestation. Twenty-two healthy babies without renal, hepatic, auditory, or hematopoietic impairment were delivered. Platinum concentrations in umbilical cord blood and amniotic fluid were 23-65% and 11-42% of the maternal blood, respectively. This series on in vivo measurement of platinum concentrations in the fetomaternal compartment observed that because of consistently lower platinum values in the fetoplacental unit, a placental filtration mechanism of platinum may be assumed. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Long Hole Film Cooling Dataset for CFD Development . Part 1; Infrared Thermography and Thermocouple Surveys

    Science.gov (United States)

    Shyam, Vikram; Thurman, Douglas; Poinsatte, Phillip; Ameri, Ali; Eichele, Peter; Knight, James

    2013-01-01

    An experiment investigating flow and heat transfer of long (length to diameter ratio of 18) cylindrical film cooling holes has been completed. In this paper, the thermal field in the flow and on the surface of the film cooled flat plate is presented for nominal freestream turbulence intensities of 1.5 and 8 percent. The holes are inclined at 30deg above the downstream direction, injecting chilled air of density ratio 1.0 onto the surface of a flat plate. The diameter of the hole is 0.75 in. (0.01905 m) with center to center spacing (pitch) of 3 hole diameters. Coolant was injected into the mainstream flow at nominal blowing ratios of 0.5, 1.0, 1.5, and 2.0. The Reynolds number of the freestream was approximately 11,000 based on hole diameter. Thermocouple surveys were used to characterize the thermal field. Infrared thermography was used to determine the adiabatic film effectiveness on the plate. Hotwire anemometry was used to provide flowfield physics and turbulence measurements. The results are compared to existing data in the literature. The aim of this work is to produce a benchmark dataset for Computational Fluid Dynamics (CFD) development to eliminate the effects of hole length to diameter ratio and to improve resolution in the near-hole region. In this report, a Time-Filtered Navier Stokes (TFNS), also known as Partially Resolved Navier Stokes (PRNS), method that was implemented in the Glenn-HT code is used to model coolant-mainstream interaction. This method is a high fidelity unsteady method that aims to represent large scale flow features and mixing more accurately.

  11. Exploring Soot Particle Concentration and Emissivity by Transient Thermocouples Measurements in Laminar Partially Premixed Coflow Flames

    Directory of Open Access Journals (Sweden)

    Gianluigi De Falco

    2017-02-01

    Full Text Available Soot formation in combustion represents a complex phenomenon that strongly depends on several factors such as pressure, temperature, fuel chemical composition, and the extent of premixing. The effect of partial premixing on soot formation is of relevance also for real combustion devices and still needs to be fully understood. An improved version of the thermophoretic particle densitometry (TPD method has been used in this work with the aim to obtain both quantitative and qualitative information of soot particles generated in a set of laminar partially-premixed coflow flames characterized by different equivalence ratios. To this aim, the transient thermocouple temperature response has been analyzed to infer particle concentration and emissivity. A variety of thermal emissivity values have been measured for flame-formed carbonaceous particles, ranging from 0.4 to 0.5 for the early nucleated soot particles up to the value of 0.95, representing the typical value commonly attributed to mature soot particles, indicating that the correct determination of the thermal emissivity is necessary to accurately evaluate the particle volume fraction. This is particularly true at the early stage of the soot formation, when particle concentration measurement is indeed particularly challenging as in the central region of the diffusion flames. With increasing premixing, an initial increase of particles is detected both in the maximum radial soot volume fraction region and in the central region of the flame, while the further addition of primary air determines the particle volume fraction drop. Finally, a modeling analysis based on a sectional approach has been performed to corroborate the experimental findings.

  12. Green synthesis and characterisation of platinum nanoparticles using quail egg yolk

    Science.gov (United States)

    Nadaroglu, Hayrunnisa; Gungor, Azize Alayli; Ince, Selvi; Babagil, Aynur

    2017-02-01

    Nanotechnology is extensively used in all parts today. Therefore, nano synthesis is also significant in all explored areas. The results of studies conducted have revealed that nanoparticle synthesis is performed by using both chemical and physical methods. It is well known that these syntheses are carried out at high charge, pressure and temperature in harsh environments. Therefore, this study investigated green synthesis method that sustains more mild conditions. In this study, quail egg yolk having high vitamin and protein content was prepared for green synthesis reaction and used for the synthesis of platinum nanoparticles in the reaction medium. Reaction situations were optimised as a function of pH, temperature, time and concentration by using quail egg yolk. The results showed that the highest platinum nanoparticles were synthesised at 20 °C and pH 6.0 for 4 h. Also, optimal concentration of metal ions was established as 0.5 mM. The synthesised platinum nanoparticles were characterised by using UV spectrum, X-ray diffraction and scanning electron microscope.

  13. Membrane fuel cell cathode catalysts based on titanium oxide supported platinum nanoparticles.

    Science.gov (United States)

    Gebauer, Christian; Jusys, Zenonas; Wassner, Maximilian; Hüsing, Nicola; Behm, R Jürgen

    2014-07-21

    The potential of platinum catalysts supported on pure, nitrogen-, or carbon-doped titania for application in the oxygen reduction reaction (ORR), as a cathode catalyst in polymer electrolyte membrane fuel cells, is investigated. The oxide supports are synthesized by using a sol-gel route. Modification with nitrogen and carbon doping is achieved by thermal decomposition of urea and the structure-directing agent P123. Platinum nanoparticles are prepared by reduction of a Pt(IV) salt in ethylene glycol and subsequently immobilized on different support materials. Structural and electronic properties of the support materials and the resulting catalysts are characterized by various methods, including X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. These results and electrochemical characterization of the support materials and platinum nanoparticle catalysts indicate distinct support effects in the catalysts. The electrocatalytic performance of these catalysts in the ORR, as determined in rotating ring disc electrode measurements, is promising. Also here, distinct support effects can be identified. Correlations with the structural/electronic and the electrochemical properties are discussed, as well as the role of metal-support interactions.

  14. Platinum supported catalysts for carbon monoxide preferential oxidation: Study of support influence

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, R.; Rodriguez, L.; Serrano-Lotina, A.; Daza, L. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain); Benito, M. [Instituto de Catalisis y Petroleoquimica (CSIC), C/Marie Curie 2, Campus Cantoblanco, 28049 Madrid (Spain); Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain)

    2009-07-01

    The aim of this work is to study the influence of the addition of different oxides to an alumina support, on surface acidity and platinum reducibility in platinum-based catalysts, as well as their effect on the activity and selectivity in CO preferential oxidation, in presence of hydrogen. A correlation between surface acidity and acid strength of surface sites and metal reducibility was obtained, being Pt-support interaction a function of the acid sites concentration under a particular temperature range. In platinum supported on alumina catalysts, CO oxidation follows a Langmuir-Hinshelwood mechanism, where O{sub 2} and CO compete in the adsorption on the same type of active sites. It is noteworthy that the addition of La{sub 2}O{sub 3} modifies the reaction mechanism. In this case, CO is not only adsorbed on the Pt active sites but also on La{sub 2}O{sub 3}, forming bridge bonded carbonates which leads to high reactivity at low temperatures. An increase on temperature produces CO desorption from Pt surface sites and favours oxygen adsorption producing CO{sub 2}. CO oxidation with surface hydroxyl groups was activated producing simultaneously CO{sub 2} and H{sub 2}. (author)

  15. Oxidation of H2 and CO in a fuel cell with a Platinum-tin Anode

    Directory of Open Access Journals (Sweden)

    Javier González

    2010-06-01

    Full Text Available This report describes the construction and evolution of a fuel cell with a bi-metallic anode of Pt-Sn supported on carbon, as catalysts for oxidation of pure hydrogen, pure CO and a 2% CO in H2 mixture. Both, cathode and anode were made with a structure composed by a diffusive layer and a catalytic layer. The diffusive layer was made with a carbon cloth while the catalytic layer contained the platinum and tin supported on carbon. To test the performance of the catalytic mixture, a proton exchange membrane fuel cell (PEMFC was developed with an original design for the gas distributation plates. The reactants were feed to ambient temperature and 3 psig in the anode side, while 5 psig pure oxygen was used in the cathode. The anode catalytic load was 0.57 mg/cm2 of platinum and 0.08 mg/cm2 of tin. The catalytic load in cathode was 0.85 mg/cm2 of pure platinum. It was found that this caralytic mixture is tolerant to CO presence.

  16. Biomarkers to assess the efficiency of treatment with platinum-based drugs: what can metallomics add?

    Science.gov (United States)

    Araujo, Thiago de O; Costa, Lilian T; Fernandes, Janaina; Aucélio, Ricardo Queiroz; de Campos, Reinaldo Calixto

    2014-12-01

    Since the approval of cisplatin as an antineoplastic drug, the medical and the scientific communities have been concerned about the side effects of platinum-based drugs, and this has been the dose-limiting factor that leads to reduced treatment efficiency. Another important issue is the intrinsic or acquired resistance of some patients to treatment. Identifying proper biomarkers is crucial in evaluating the efficiency of a treatment, assisting physicians in determining, at early stages, whether or not the patient presents resistance to the drug, minimizing severe side effects, and allowing them to redirect the established course of chemotherapy. A great effort is being made to identify biomarkers that can be used to predict the outcome of the treatment of cancer patients with platinum-based drugs. In this context, the metallomic approach has not yet been used to its full potential. Since the basis of these drugs is platinum, the monitoring of biomarkers containing this metal should be the natural approach to evaluate treatment progress. This review intends to show where the research in this field stands and points out some gaps that can be filled by metallomics.

  17. Sequential Electrodeposition of Platinum-Ruthenium at Boron-Doped Diamond Electrodes for Methanol Oxidation

    Directory of Open Access Journals (Sweden)

    Ileana González-González

    2011-01-01

    Full Text Available Sequential electrodeposition of Pt and Ru on boron-doped diamond (BDD films, in 0.5 M H2SO4 by cyclic voltammetry, has been prepared. The potential cycling, in the aqueous solutions of the respective metals, was between 0.00 and 1.00 V versus Ag/AgCl. The catalyst composites, Pt and PtRu, deposited on BDD film substrates, were tested for methanol oxidation. The modified diamond surfaces were also characterized by scanning electron microscopy-X-ray fluorescence-energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The scanning Auger electron spectroscopy mapping showed the ruthenium signal only in areas where platinum was electrodeposited. Ruthenium does not deposit on the oxidized diamond surface of the boron-doped diamond. Particles with 5–10% of ruthenium with respect to platinum exhibited better performance for methanol oxidation in terms of methanol oxidation peak current and chronoamperometric current stability. The electrogenerated •OH radicals on BDD may interact with Pt surface, participating in the methanol oxidation as shown in oxidation current and the shift in the peak position. The conductive diamond surface is a good candidate as the support for the platinum electrocatalyst, because it ensures catalytic activity, which compares with the used carbon, and higher stability under severe anodic and cathodic conditions.

  18. The effect of intermolecular hydrogen bonding on the fluorescence of a bimetallic platinum complex.

    Science.gov (United States)

    Zhao, Guang-Jiu; Northrop, Brian H; Han, Ke-Li; Stang, Peter J

    2010-09-02

    The bimetallic platinum complexes are known as unique building blocks and arewidely utilized in the coordination-driven self-assembly of functionalized supramolecular metallacycles. Hence, photophysical study of the bimetallic platinum complexes will be very helpful for the understanding on the optical properties and further applications of coordination-driven self-assembled supramolecular metallacycles. Herein, we report steady-state and time-resolved spectroscopic experiments as well as quantum chemistry calculations to investigate the significant intermolecular hydrogen bonding effects on the intramolecular charge transfer (ICT) fluorescence of a bimetallic platinum compound 4,4'-bis(trans-Pt(PEt(3))(2)OTf)benzophenone 3 in solution. We demonstrated that the fluorescent state of compound 3 can be assigned as a metal-to-ligand charge transfer (MLCT) state. Moreover, it was observed that the formation of intermolecular hydrogen bonds can effectively lengthen the fluorescence lifetime of 3 in alcoholic solvents compared with that in hexane solvent. At the same time, the electronically excited states of 3 in solution are definitely changed by intermolecular hydrogen bonding interactions. As a consequence, we propose a new fluorescence modulation mechanism by hydrogen bonding to explain different fluorescence emissions of 3 in hydrogen-bonding solvents and nonhydrogen-bonding solvents.

  19. Investigation of mechanical and structural characteristics of platinum and palladium at high temperatures

    Directory of Open Access Journals (Sweden)

    Trumic, Biserka T.

    2015-03-01

    Full Text Available In order to broaden future application of products based on platinum and palladium a comparative analysis of their high-temperature mechanical properties was performed. Platinum and palladium are of great importance and are widely used in chemical industry, electronics, for making laboratory dishes, to name a few. Mechanical properties of pure metals, such as: tensile strength, creep rate and rupture time were investigated using universal testing machine for tensile testing of materials. Microstructure of samples was investigated by optical microscopy. Based on obtained results it can be concluded that the platinum, compared to palladium, is superior for high-temperature applications.Se realiza un estudio comparativo de las propiedades mecánicas a alta temperatura del platino y paladio, con el fin de ampliar las aplicaciones de los productos basados en estos metales. El platino y el paladio son de gran importancia y se utilizan ampliamente en la industria química, electrónica y para la fabricación de placas de laboratorio, entre otras aplicaciones. Se estudiaron las siguientes propiedades mecánicas de los metales puros: resistencia a la tracción, velocidad de fluencia y tiempo de rotura bajo condiciones de fluencia. Para esas investigaciones se utilizó una máquina universal de ensayos para realizar los ensayos de tracción. La micro- estructura fue investigada por microscopía óptica. Basándose en los resultados obtenidos, se puede concluir que el platino, en comparación con el paladio, presenta mejores prestaciones para aplicaciones a alta temperatura.

  20. Permeation of platinum and rhodium nanoparticles through intact and damaged human skin

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, Marcella [University of Trieste, Clinical Unit of Occupational Medicine, Department of Medical Sciences (Italy); Crosera, Matteo; Bianco, Carlotta; Adami, Gianpiero; Montini, Tiziano; Fornasiero, Paolo [University of Trieste, Department of Chemical and Pharmaceutical Sciences (Italy); Jaganjac, Morana [Rudjer Boskovic Institute, Laboratory for Oxidative Stress, Department of Molecular Medicine (Croatia); Bovenzi, Massimo; Filon, Francesca Larese, E-mail: larese@units.it [University of Trieste, Clinical Unit of Occupational Medicine, Department of Medical Sciences (Italy)

    2015-06-15

    The aim of the study was to evaluate percutaneous penetration of platinum and rhodium nanoparticles (PtNPs: 5.8 ± 0.9 nm, RhNPs: 5.3 ± 1.9 nm) through human skin. Salts compounds of these metals are sensitizers and some also carcinogenic agents. In vitro permeation experiments were performed using Franz diffusion cells with intact and damaged skin. PtNPs and RhNPs, stabilized with polyvinylpyrrolidone, were synthesized by reduction of Na{sub 2}PtC{sub l6} and RhCl{sub 3}·3H{sub 2}O respectively. Suspensions with a concentration of 2.0 g/L of PtNPs and RhNPs were dispersed separately in synthetic sweat at pH 4.5 and applied as donor phases to the outer surface of the skin for 24 h. Measurements of the content of the metals in the receiving solution and in the skin were performed subsequently. Rhodium skin permeation was demonstrated through damaged skin, with a permeation flux of 0.04 ± 0.04 μg cm{sup −2} h{sup −1} and a lag time of 7.9 ± 1.1 h, while no traces of platinum were found in receiving solutions. Platinum and rhodium skin-analysis showed significantly higher concentrations of the metals in damaged skin. Rh and Pt applied as NPs can penetrate the skin barrier and Rh can be found in receiving solutions. These experiments pointed out the need for skin contamination prevention, since even a minor injury to the skin barrier can significantly increase penetration.