WorldWideScience

Sample records for high temperature electronics materials

  1. High-Temperature Electronic Materials: Silicon Carbide and Diamond

    Science.gov (United States)

    Willander, Magnus; Friesel, Milan; Wahab, Qamar-Ul; Straumal, Boris

    The physical and chemical properties of wide-band-gap semiconductors make these materials an ideal choice for device fabrication for applications in many different areas, e.g. light emitters, high-temperature and high-power electronics, high-power microwave devices, micro-electromechanical system (MEM) technology, and substrates for semiconductor preparation. These semiconductors have been recognized for several decades as being suitable for these applications, but until recently the low material quality has not allowed the fabrication of high-quality devices. In this chapter, we review the wide-band-gap semiconductors, silicon carbide and diamond.

  2. 500 C Electronic Packaging and Dielectric Materials for High Temperature Applications

    Science.gov (United States)

    Chen, Liang-yu; Neudeck, Philip G.; Spry, David J.; Beheim, Glenn M.; Hunter, Gary W.

    2016-01-01

    High-temperature environment operable sensors and electronics are required for exploring the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high temperature electronics, and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by these high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed. High-temperature environment operable sensors and electronics are required for probing the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and eventual applications of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high electronics and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed.

  3. High temperature superconducting materials

    Energy Technology Data Exchange (ETDEWEB)

    Alario-Franco, M.A. [Universidad Complutense de Madrid (Spain). Facultad de Ciencias Quimicas

    1995-02-01

    The perovskite structure is the basis of all known high-temperature superconducting materials. Many of the most successful (highest T{sub c}) materials are based on mercury and thallium phases but, due to the high toxicity of the component compounds effort has been invested in the substitution of these elements with silver. Progress is reviewed. (orig.)

  4. High temperature materials and mechanisms

    CERN Document Server

    2014-01-01

    The use of high-temperature materials in current and future applications, including silicone materials for handling hot foods and metal alloys for developing high-speed aircraft and spacecraft systems, has generated a growing interest in high-temperature technologies. High Temperature Materials and Mechanisms explores a broad range of issues related to high-temperature materials and mechanisms that operate in harsh conditions. While some applications involve the use of materials at high temperatures, others require materials processed at high temperatures for use at room temperature. High-temperature materials must also be resistant to related causes of damage, such as oxidation and corrosion, which are accelerated with increased temperatures. This book examines high-temperature materials and mechanisms from many angles. It covers the topics of processes, materials characterization methods, and the nondestructive evaluation and health monitoring of high-temperature materials and structures. It describes the ...

  5. High Temperature Materials Laboratory (HTML)

    Data.gov (United States)

    Federal Laboratory Consortium — The six user centers in the High Temperature Materials Laboratory (HTML), a DOE User Facility, are dedicated to solving materials problems that limit the efficiency...

  6. Very heavily electron-doped CrSi2 as a high-performance high-temperature thermoelectric material

    Science.gov (United States)

    Parker, David; Singh, David J.

    2012-03-01

    We analyze the thermoelectric behavior, using first principles and Boltzmann transport calculations, of very heavily electron-doped CrSi2 and find that at temperatures of 900-1250 K and electron dopings of 1-4 × 1021 cm-3, thermopowers as large in magnitude as 200 μV K-1 may be found. Such high thermopowers at such high carrier concentrations are extremely rare, and suggest that excellent thermoelectric performance may be found in these ranges of temperature and doping.

  7. High temperature materials; Materiaux a hautes temperatures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  8. Development and characterization of high temperature, high energy density dielectric materials to establish routes towards power electronics capacitive devices

    Science.gov (United States)

    Shay, Dennis P.

    The maximum electrostatic energy density of a capacitor is a function of the relative permittivity (epsilonr) and the square of the dielectric breakdown strength (Eb). Currently, state-of-the art high temperature (>200 °C), SiC-based power electronics utilize CaZrO3-rich NP0/C0G-type capacitors, which have low relative permittivities of epsilonr ˜ 30-40, high breakdown strengths (> 1.0 MV/cm), and are chosen for their minimal change in energy storage with temperature. However, with operating temperatures exceeding the rated temperatures for such capacitors, there is an opportunity to develop new dielectric ceramics having higher energy densities and volumetric efficiencies at high temperatures (>200 °C) by utilizing higher permittivity dielectrics while maintaining high breakdown strengths via doping. The solid solution behavior of was characterized in order to determine the optimal composition for balancing permittivity and dielectric breakdown strength to obtain high energy densities at elevated temperatures. Characterization by X-ray diffraction (XRD) showed Vegard's law behavior across the solid solution with minimal 2nd phases. To determine a Ca(TixZr1-x)O3 composition that will also minimize electronic or band conduction, the optical properties of the Ca(TixZr1-x)O3 solid solution were investigated to identify a composition on the CaTiO3 - rich end of the solid solution with a large band gap. Both ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis) and spectroscopic ellipsometry were utilized to determine the Ca(TixZr1-x)O3 band gaps and optical properties. The resistivity at 250 °C scaled with the band gap energy across the solid solution. Comparing the current-voltage (I--V) behavior at 250 °C for Ca(Tix-yMnyZr0.2)O3 (CTZ + Mn) where x = 0.7, 0.8, 0.9, and y = 0.005, it was found that the Ca(Ti 0.795Mn0.005Zr0.2)O3 composition showed the lowest current density and a decrease in current density of 5 orders of magnitude compared to the un

  9. Electrons and Phonons in High Temperature Superconductors

    Directory of Open Access Journals (Sweden)

    Anu Singh

    2013-01-01

    Full Text Available The defect-induced anharmonic phonon-electron problem in high-temperature superconductors has been investigated with the help of double time thermodynamic electron and phonon Green’s function theory using a comprehensive Hamiltonian which includes the contribution due to unperturbed electrons and phonons, anharmonic phonons, impurities, and interactions of electrons and phonons. This formulation enables one to resolve the problem of electronic heat transport and equilibrium phenomenon in high-temperature superconductors in an amicable way. The problem of electronic heat capacity and electron-phonon problem has been taken up with special reference to the anharmonicity, defect concentration electron-phonon coupling, and temperature dependence.

  10. Deep Trek High Temperature Electronics Project

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Ohme

    2007-07-31

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  11. Symposium on high temperature and materials chemistry

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

    This volume contains the written proceedings of the Symposium on High Temperature and Materials Chemistry held in Berkeley, California on October 24--25, 1989. The Symposium was sponsored by the Materials and Chemical Sciences Division of Lawrence Berkeley Laboratory and by the College of Chemistry of the University of California at Berkeley to discuss directions, trends, and accomplishments in the field of high temperature and materials chemistry. Its purpose was to provide a snapshot of high temperature and materials chemistry and, in so doing, to define status and directions.

  12. High-temperature levitated materials

    National Research Council Canada - National Science Library

    Price, David L

    2010-01-01

    .... This can be avoided by suspending the sample through levitation. This technique also makes metastable states of matter accessible, opening up new avenues of scientific enquiry, as well as possible new materials for technological applications...

  13. Thermodynamics of High Temperature Materials.

    Science.gov (United States)

    1985-03-15

    temperatures In the present range have also been obtained by Krauss and Warncke [8] and by Vollmer et al. [9], using adiabatic calorimetry, and by Kollie [10...value for heat capacity. The electrical resistivity results reported by Kollie [10] and by Powell et al. [13] are respectively about 1 and 1.5% lower...extensive annealing of the specimens used in the measurements: the specimen (>99.89% pure) used by Kollie was annealed at 1100 K for 24 h and Laubitz et al

  14. Materials for high-temperature fuel cells

    CERN Document Server

    Jiang, San Ping; Lu, Max

    2013-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in High-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in high-temperature fuel cells with emphasis on the most important solid oxide fuel cells. A related book will cover key mater

  15. Electron beam damage in high temperature polymers

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. (Dayton Univ., OH (USA). Research Inst.); Adams, W.W. (Air Force Materials Lab., Wright-Patterson AFB, OH (USA))

    1990-01-01

    Electron microscopic studies of polymers are limited due to beam damage. Two concerns are the damage mechanism in a particular material, and the maximum dose for a material before damage effects are observed. From the knowledge of the dose required for damage to the polymer structure, optimum parameters for electron microscopy imaging can be determined. In the present study, electron beam damage of polymers has been quantified by monitoring changes in the diffraction intensity as a function of electron dose. The beam damage characteristics of the following polymers were studied: poly(p-phenylene benzobisthiazole) (PBZT); poly(p-phenylene benzobisoxazole) (PBO); poly(benzoxazole) (ABPBO); poly(benzimidazole) (ABPBI); poly(p-phenylene terephthalamide) (PPTA); and poly(aryl ether ether ketone) (PEEK). Previously published literature results on polyethylene (PE), polyoxymethylene (POM), nylon-6, poly(ethylene oxide) (PEO), PBZT, PPTA, PPX, iPS, poly(butylene terephthalate) (PBT), and poly(phenylene sulphide) (PPS) were reviewed. This study demonstrates the strong dependence of the electron beam resistivity of a polymer on its thermal stability/melt temperature. (author).

  16. Diamond switches for high temperature electronics

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, R.R.; Rondeau, G.; Qi, Niansheng [Alameda Applied Sciences Corp., San Leandro, CA (United States)] [and others

    1996-04-25

    Diamond switches are well suited for use in high temperature electronics. Laboratory feasibility of diamond switching at 1 kV and 18 A was demonstrated. DC blocking voltages up to 1 kV were demonstrated. A 50 {Omega} load line was switched using a diamond switch, with switch on-state resistivity {approx}7 {Omega}-cm. An electron beam, {approx}150 keV energy, {approx}2 {mu}s full width at half maximum was used to control the 5 mm x 5 mm x 100 {mu}m thick diamond switch. The conduction current temporal history mimics that of the electron beam. These data were taken at room temperature.

  17. Electronic phase separation and high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kivelson, S.A. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics; Emery, V.J. [Brookhaven National Lab., Upton, NY (United States)

    1994-01-11

    The authors review the extensive evidence from model calculations that neutral holes in an antiferromagnet separate into hole-rich and hole-poor phases. All known solvable limits of models of holes in a Heisenberg antiferromagnet exhibit this behavior. The authors show that when the phase separation is frustrated by the introduction of long-range Coulomb interactions, the typical consequence is either a modulated (charge density wave) state or a superconducting phase. The authors then review some of the strong experimental evidence supporting an electronically-driven phase separation of the holes in the cuprate superconductors and the related Ni oxides. Finally, the authors argue that frustrated phase separation in these materials can account for many of the anomalous normal state properties of the high temperature superconductors and provide the mechanism of superconductivity. In particular, it is shown that the T-linear resistivity of the normal state is a paraconductivity associated with a novel composite pairing, although the ordered superconducting state is more conventional.

  18. High Temperature Materials Characterization and Advanced Materials Development

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Seog; Kim, D. H.; Kim, S. H. (and others)

    2007-06-15

    The project has been carried out for 2 years in stage III in order to achieve the final goals of performance verification of the developed materials, after successful development of the advanced high temperature material technologies for 3 years in Stage II. The mechanical and thermal properties of the advanced materials, which were developed during Stage II, were evaluated at high temperatures, and the modification of the advanced materials were performed. Moreover, a database management system was established using user-friendly knowledge-base scheme to complete the integrated-information material database in KAERI material division.

  19. Comparison of electron beam and laser beam powder bed fusion additive manufacturing process for high temperature turbine component materials

    Energy Technology Data Exchange (ETDEWEB)

    Dryepondt, Sebastien N [ORNL; Kirka, Michael M [ORNL; Pint, Bruce A [ORNL; Ryan, Daniel [Solar Turbines, Inc.

    2016-04-01

    The evolving 3D printer technology is now at the point where some turbine components could be additive manufactured (AM) for both development and production purposes. However, this will require a significant evaluation program to qualify the process and components to meet current design and quality standards. The goal of the project was to begin characterization of the microstructure and mechanical properties of Nickel Alloy X (Ni-22Cr-18Fe-9Mo) test bars fabricated by powder bed fusion (PBF) AM processes that use either an electron beam (EB) or laser beam (LB) power source. The AM materials produced with the EB and LB processes displayed significant differences in microstructure and resultant mechanical properties. Accordingly, during the design analysis of AM turbine components, the specific mechanical behavior of the material produced with the selected AM process should be considered. Comparison of the mechanical properties of both the EB and LB materials to those of conventionally processed Nickel Alloy X materials indicates the subject AM materials are viable alternatives for manufacture of some turbine components.

  20. Materials for High-Temperature Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ersson, Anders

    2003-04-01

    Catalytic combustion is an environmentally friendly technique to combust fuels in e.g. gas turbines. Introducing a catalyst into the combustion chamber of a gas turbine allows combustion outside the normal flammability limits. Hence, the adiabatic flame temperature may be lowered below the threshold temperature for thermal NO{sub X} formation while maintaining a stable combustion. However, several challenges are connected to the application of catalytic combustion in gas turbines. The first part of this thesis reviews the use of catalytic combustion in gas turbines. The influence of the fuel has been studied and compared over different catalyst materials. The material section is divided into two parts. The first concerns bimetallic palladium catalysts. These catalysts showed a more stable activity compared to their pure palladium counterparts for methane combustion. This was verified both by using an annular reactor at ambient pressure and a pilot-scale reactor at elevated pressures and flows closely resembling the ones found in a gas turbine combustor. The second part concerns high-temperature materials, which may be used either as active or washcoat materials. A novel group of materials for catalysis, i.e. garnets, has been synthesised and tested in combustion of methane, a low-heating value gas and diesel fuel. The garnets showed some interesting abilities especially for combustion of low-heating value, LHV, gas. Two other materials were also studied, i.e. spinels and hexa aluminates, both showed very promising thermal stability and the substituted hexa aluminates also showed a good catalytic activity. Finally, deactivation of the catalyst materials was studied. In this part the sulphur poisoning of palladium, platinum and the above-mentioned complex metal oxides has been studied for combustion of a LHV gas. Platinum and surprisingly the garnet were least deactivated. Palladium was severely affected for methane combustion while the other washcoat materials were

  1. Applications of Silicon Carbide for High Temperature Electronics and Sensors

    Science.gov (United States)

    Shields, Virgil B.

    1995-01-01

    Silicon carbide (SiC) is a wide bandgap material that shows great promise in high-power and high temperature electronics applications because of its high thermal conductivity and high breakdown electrical field. The excellent physical and electronic properties of SiC allows the fabrication of devices that can operate at higher temperatures and power levels than devices produced from either silicon or GaAs. Although modern electronics depends primarily upon silicon based devices, this material is not capable of handling may special requirements. Devices which operate at high speeds, at high power levels and are to be used in extreme environments at high temperatures and high radiation levels need other materials with wider bandgaps than that of silicon. Many space and terrestrial applications also have a requirement for wide bandgap materials. SiC also has great potential for high power and frequency operation due to a high saturated drift velocity. The wide bandgap allows for unique optoelectronic applications, that include blue light emitting diodes and ultraviolet photodetectors. New areas involving gas sensing and telecommunications offer significant promise. Overall, the properties of SiC make it one of the best prospects for extending the capabilities and operational regimes of the current semiconductor device technology.

  2. High Temperature Materials Laboratory third annual report

    Energy Technology Data Exchange (ETDEWEB)

    Tennery, V.J.; Foust, F.M.

    1990-12-01

    The High Temperature Materials Laboratory has completed its third year of operation as a designated DOE User Facility at the Oak Ridge National Laboratory. Growth of the user program is evidenced by the number of outside institutions who have executed user agreements since the facility began operation in 1987. A total of 88 nonproprietary agreements (40 university and 48 industry) and 20 proprietary agreements (1 university, 19 industry) are now in effect. Sixty-eight nonproprietary research proposals (39 from university, 28 from industry, and 1 other government facility) and 8 proprietary proposals were considered during this reporting period. Research projects active in FY 1990 are summarized.

  3. High Temperature Integrated Thermoelectric Ststem and Materials

    Energy Technology Data Exchange (ETDEWEB)

    Mike S. H. Chu

    2011-06-06

    The final goal of this project is to produce, by the end of Phase II, an all ceramic high temperature thermoelectric module. Such a module design integrates oxide ceramic n-type, oxide ceramic p-type materials as thermoelectric legs and oxide ceramic conductive material as metalizing connection between n-type and p-type legs. The benefits of this all ceramic module are that it can function at higher temperatures (> 700 C), it is mechanically and functionally more reliable and it can be scaled up to production at lower cost. With this all ceramic module, millions of dollars in savings or in new opportunities recovering waste heat from high temperature processes could be made available. A very attractive application will be to convert exhaust heat from a vehicle to reusable electric energy by a thermoelectric generator (TEG). Phase I activities were focused on evaluating potential n-type and p-type oxide compositions as the thermoelectric legs. More than 40 oxide ceramic powder compositions were made and studied in the laboratory. The compositions were divided into 6 groups representing different material systems. Basic ceramic properties and thermoelectric properties of discs sintered from these powders were measured. Powders with different particles sizes were made to evaluate the effects of particle size reduction on thermoelectric properties. Several powders were submitted to a leading thermoelectric company for complete thermoelectric evaluation. Initial evaluation showed that when samples were sintered by conventional method, they had reasonable values of Seebeck coefficient but very low values of electrical conductivity. Therefore, their power factors (PF) and figure of merits (ZT) were too low to be useful for high temperature thermoelectric applications. An unconventional sintering method, Spark Plasma Sintering (SPS) was determined to produce better thermoelectric properties. Particle size reduction of powders also was found to have some positive benefits

  4. High temperature material characterization and advanced materials development

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Seog; Kim, D. H.; Kim, S. H. and others

    2005-03-15

    The study is to characterize the structural materials under the high temperature, one of the most significant environmental factors in nuclear systems. And advanced materials are developed for high temperature and/or low activation in neutron irradiation. Tensile, fatigue and creep properties have been carried out at high temperature to evaluate the mechanical degradation. Irradiation tests were performed using the HANARO. The optimum chemical composition and heat treatment condition were determined for nuclear grade 316NG stainless steel. Nitrogen, aluminum, and tungsten were added for increasing the creep rupture strength of FMS steel. The new heat treatment method was developed to form more stable precipitates. By applying the novel whiskering process, high density SiC/SiC composites with relative density above 90% could be obtained even in a shorter processing time than the conventional CVI process. Material integrated databases are established using data sheets. The databases of 6 kinds of material properties are accessible through the home page of KAERI material division.

  5. Packaging Technology for SiC High Temperature Electronics

    Science.gov (United States)

    Chen, Liang-Yu; Neudeck, Philip G.; Spry, David J.; Meredith, Roger D.; Nakley, Leah M.; Beheim, Glenn M.; Hunter, Gary W.

    2017-01-01

    High-temperature environment operable sensors and electronics are required for long-term exploration of Venus and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500 C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors in relevant environments. This talk will discuss a ceramic packaging system developed for high temperature electronics, and related testing results of SiC integrated circuits at 500 C facilitated by this high temperature packaging system, including the most recent progress.

  6. High temperature electronics and instrumentation seminar proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Veneruso, A.F.; Arnold, C.; Simpson, R.S. (eds.)

    1980-05-01

    This seminar was tailored to address the needs of the borehole logging industry and to stimulate the development and application of this technology, for logging geothermal, hot oil and gas, and steam injection wells. The technical sessions covered the following topics: hybrid circuits, electronic devices, transducers, cables and connectors, materials, mechanical tools and thermal protection. Thirty-eight papers are included. Separate entries were prepared for each one. (MHR)

  7. Sourcebook on high-temperature electronics and instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Veneruso, A.F. (ed.)

    1981-10-01

    This sourcebook summarizes the high-temperature characteristics of a number of commercially available electronic components and materials required in geothermal well-logging instruments that must operate to 275/sup 0/C. The sourcebook is written to provide a starting place for instrument designers, who need to know the high-temperature electronic products that are available and the design and performance limitations of these products. The electronic component information given includes the standard repertoire of passive devices such as resistors, capacitors, and magnetics; the active devices and integrated circuits sections emphasize silicon semiconductor JFETs and CMOS circuits; and, to complete the electronics, interconnections and packaging of hybrid microelectronics are described. Thermal insulation and refrigeration alternatives are also presented in the sourcebook. Finally, instrument housing materials and high-temperature cables and cablehead connectors are listed. This information was compiled as part of the Geothermal Logging Instrumentation Development Program that Sandia National Laboratories conducted for the US Department of Energy's Divison of Geothermal Energy from 1976 to 1981.

  8. Study of High Temperature Insulation Materials

    Directory of Open Access Journals (Sweden)

    Vaclav Mentlik

    2004-01-01

    Full Text Available One of current objectives of the electro insulating technology is the development of the material for extreme conditions. There is a need to operate some devices in extreme temperatures, for example the propulsion of the nuclear fuel bars. In these cases there is necessary to provide not just insulating property, but also the thermal endurance with the required durability of the insulating materials. Critical is the determination of the limit stress for the irreversible structure modification with relation to material property changes. For this purpose there is necessary to conduct lot of test on chosen materials to determine the limits mentioned above. Content of this article is the definition of diagnostic mode, including the definition of the exposure factors, definitions of the diagnostic system for data acquisition and first result of examinations.

  9. Advances in High Temperature Materials for Additive Manufacturing

    Science.gov (United States)

    Nordin, Nurul Amira Binti; Johar, Muhammad Akmal Bin; Ibrahim, Mohd Halim Irwan Bin; Marwah, Omar Mohd Faizan bin

    2017-08-01

    In today’s technology, additive manufacturing has evolved over the year that commonly known as 3D printing. Currently, additive manufacturing have been applied for many industries such as for automotive, aerospace, medical and other commercial product. The technologies are supported by materials for the manufacturing process to produce high quality product. Plus, additive manufacturing technologies has been growth from the lowest to moderate and high technology to fulfil manufacturing industries obligation. Initially from simple 3D printing such as fused deposition modelling (FDM), poly-jet, inkjet printing, to selective laser sintering (SLS), and electron beam melting (EBM). However, the high technology of additive manufacturing nowadays really needs high investment to carry out the process for fine products. There are three foremost type of material which is polymer, metal and ceramic used for additive manufacturing application, and mostly they were in the form of wire feedstock or powder. In circumstance, it is crucial to recognize the characteristics of each type of materials used in order to understand the behaviours of the materials on high temperature application via additive manufacturing. Therefore, this review aims to provide excessive inquiry and gather the necessary information for further research on additive material materials for high temperature application. This paper also proposed a new material based on powder glass, which comes from recycled tempered glass from automotive industry, having a huge potential to be applied for high temperature application. The technique proposed for additive manufacturing will minimize some cost of modelling with same quality of products compare to the others advanced technology used for high temperature application.

  10. First high-temperature electronics products survey 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy Allen

    2006-04-01

    On April 4-5, 2005, a High-Temperature Electronics Products Workshop was held. This workshop engaged a number of governmental and private industry organizations sharing a common interest in the development of commercially available, high-temperature electronics. One of the outcomes of this meeting was an agreement to conduct an industry survey of high-temperature applications. This report covers the basic results of this survey.

  11. Electronic Structure of the Bismuth Family of High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Lisa

    2002-03-07

    High temperature superconductivity remains the central intellectual problem in condensed matter physics fifteen years after its discovery. Angle resolved photoemission spectroscopy (ARPES) directly probes the electronic structure, and has played an important role in the field of high temperature superconductors. With the recent advances in sample growth and the photoemission technique, we are able to study the electronic structure in great detail, and address regimes that were previously inaccessible. This thesis work contains systematic photoemission studies of the electronic structure of the Bi-family of high temperature superconductors, which include the single-layer system (Bi2201), the bi-layer system (Bi2212), and the tri-layer system (Bi2223). We show that, unlike conventional BCS superconductors, phase coherence information emerges in the single particle excitation spectrum of high temperature superconductors as the superconducting peak in Bi2212. The universality and various properties of this superconducting peak are studied in various systems. We argue that the origin of the superconducting peak may provide the key to understanding the mechanism of High-Tc superconductors. In addition, we identified a new experimental energy scale in the bilayer material, the anisotropic intra-bilayer coupling energy. For a long time, it was predicted that this energy scale would cause bilayer band splitting. We observe this phenomenon, for the first time, in heavily overdoped Bi2212. This new observation requires the revision of the previous picture of the electronic excitation in the Brillouin zone boundary. As the first ARPES study of a trilayer system, various detailed electronic proper- ties of Bi2223 are examined. We show that, comparing with Bi2212, both superconducting gap and relative superconducting peak intensity become larger in Bi2223, however, the strength of the interlayer coupling within each unit cell is possibly weaker. These results suggest that the

  12. Brittle Materials Design, High Temperature Gas Turbine

    Science.gov (United States)

    1981-03-01

    Modulus and Poisson’s Ratio were determined by sonic techniques: thermal expansion values were measured on a differential dilatometer and thermal...accumulation of potentially explosive gases. 4. Thermal conductivity of the nitriding atmosphere is important for production of high quality RBSN...of varying MgO content. Measurements were conducted on a differential dilatometer from room temperatures up to 900°C, and are shown in Figure 3.2.3

  13. High Temperature Electrical Insulation Materials for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's future space science missions cannot be realized without the state of the art high temperature insulation materials of which higher working temperature, high...

  14. NOvel Refractory Materials for High Alkali, High Temperature Environments

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, J.G.; Griffin, R. (MINTEQ International, Inc.)

    2011-08-30

    Refractory materials can be limited in their application by many factors including chemical reactions between the service environment and the refractory material, mechanical degradation of the refractory material by the service environment, temperature limitations on the use of a particular refractory material, and the inability to install or repair the refractory material in a cost effective manner or while the vessel was in service. The objective of this project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al2O3 spinel or other similar magnesia/alumina containing unshaped refractory composition (castables, gunnables, shotcretes, etc) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques (in-situ phase formation, altered conversion temperatures, accelerated reactions, etc). This family of refractory compositions would then be tailored for use in high-temperature, highalkaline industrial environments like those found in the aluminum, chemical, forest products, glass, and steel industries. A research team was formed to carry out the proposed work led by Oak Ridge National Laboratory (ORNL) and was comprised of the academic institution Missouri University of Science and Technology (MS&T), and the industrial company MINTEQ International, Inc. (MINTEQ), along with representatives from the aluminum, chemical, glass, and forest products industries. The two goals of this project were to produce novel refractory compositions which will allow for improved energy efficiency and to develop new refractory application techniques which would improve the speed of installation. Also methods of hot installation were sought which would allow for hot repairs and on-line maintenance leading to reduced process downtimes and eliminating the need to cool and reheat process vessels.

  15. High Temperature Acoustic Noise Reduction Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is to use combustion synthesis techniques to manufacture ceramic-based acoustic liners capable of withstanding temperatures up to 2500?C....

  16. NOVEL REFRACTORY MATERIALS FOR HIGH ALKALI, HIGH TEMPERATURE ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.

    2012-08-01

    A project was led by Oak Ridge National Laboratory (ORNL) in collaboration with a research team comprised of the academic institution Missouri University of Science and Technology (MS&T), and the industrial company MINTEQ International, Inc. (MINTEQ), along with representatives from the aluminum, chemical, glass, and forest products industries. The project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al 2O3, MgAl2O4, or other similar spinel structured or alumina-based unshaped refractory compositions (castables, gunnables, shotcretes, etc.) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques (in-situ phase formation, altered conversion temperatures, accelerated reactions, etc). This family of refractory compositions would then be tailored for use in high-temperature, high-alkaline industrial environments like those found in the aluminum, chemical, forest products, glass, and steel industries. Both practical refractory development experience and computer modeling techniques were used to aid in the design of this new family of materials. The newly developed materials were expected to offer alternative material choices for high-temperature, high-alkali environments that were capable of operating at higher temperatures (goal of increasing operating temperature by 100-200oC depending on process) or for longer periods of time (goal of twice the life span of current materials or next process determined service increment). This would lead to less process down time, greater energy efficiency for associated manufacturing processes (more heat kept in process), and materials that could be installed/repaired in a more efficient manner. The overall project goal was a 5% improvement in energy efficiency (brought about through a 20% improvement in thermal efficiency) resulting in a savings of 3.7 TBtu/yr (7.2 billion ft3 natural gas) by the year 2030. Additionally, new

  17. Ultra High Temperature Refractory Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Legacy refractory materials that have origins dating to the original Saturn program are commonly used in current launch facilities. Although they failure to meet the...

  18. Ultra High Temperature Refractory Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Legacy refractory materials that have origins dating to the original Saturn program are commonly used in current launch facilities. Although they fail to meet the...

  19. Damage Assessment in High Temperature Materials

    National Research Council Canada - National Science Library

    Newaz, Golam M

    2000-01-01

    .... The thermal wave imaging equipment was checked for its capability in assessment of damage in various materials systems which included thermal barrier coatings, adhesively bonded composites and SiC...

  20. Brittle Materials Design, High Temperature Gas Turbine

    Science.gov (United States)

    1975-10-01

    F, J. Beebe , Washington, D.C. 20315 1 Office, Chief Research § Development, Department of the Army, ATTN: R. Ballard, Physical § Engineering...HpR^fe^ ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN, MASSACHUSETTS 02172 TECHNICAL REPORT DISTRIBUTION No. of Copies To Mr. Leslie

  1. Corrosion behaviour of construction materials for high temperature water electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey

    2010-01-01

    Different types of corrosion resistant stainless steels, Ni-based alloys as well as titanium and tantalum were evaluated as a possible metallic bipolar plate and construction material with respect to corrosion resistance under simulated conditions corresponding to the conditions in high temperature...... proton exchange membrane (PEM) water electrolysers (HTPEMWE). All samples were exposed to anodic polarisation in 85% phosphoric acid electrolyte solution. Platinum and gold plates were tested for the valid comparison. Steady-state voltammetry was used in combination with scanning electron microscopy...... and energy-dispersive X-ray spectroscopy. Results show that stainless steels are the most inclined to corrosion under high anodic polarization. Among alloys, Ni-based showed the highest corrosion resistance under conditions, simulating HTPEMWE. In particular, Inconel625 is the most promising alloy...

  2. Signature of electron-phonon interaction in high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Vinod Ashokan

    2011-09-01

    Full Text Available The theory of thermal conductivity of high temperature superconductors (HTS based on electron and phonon line width (life times formulation is developed with Quantum dynamical approach of Green's function. The frequency line width is observed as an extremely sensitive quantity in the transport phenomena of HTS as a collection of large number of scattering processes. The role of resonance scattering and electron-phonon interaction processes is found to be most prominent near critical temperature. The theory successfully explains the spectacular behaviour of high Tc superconductors in the vicinity of transition temperature. A successful agreement between theory and experiment has been obtained by analyzing the thermal conductivity data for the sample La1.8Sr0.2CuO4 in the temperature range 0 − 200K. The theory is equally and successfully applicable to all other high Tc superconductors.

  3. Plasticity In High Temperature Materials: Tantalum and Monazite

    Science.gov (United States)

    2014-03-12

    AFRL-OSR-VA-TR-2014-0065 PLASTICITY IN HIGH TEMPERATURE MATERIALS: TANTALUM AND MONAZITE Jeffrey Kysar THE TRUSTEES OF COLUMBIA UNIVERSITY IN THE...Agency Air Force Office of Scientific Research Title of Project Plasticity in High Temperature Materials: Tantalum and Monazite February 28, 2014...centered cu- bic tantalum , the methodology also demonstrated a relationship between dislocation mean free path length and GND density. A framework to

  4. Processing of extraterrestrial materials by high temperature vacuum vaporization

    Science.gov (United States)

    Grimley, R. T.; Lipschutz, M. E.

    1983-01-01

    It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

  5. Electron diffraction and high-resolution transmission electron microscopy of the high temperature crystal structures of GexSb2Te3+x (x=1,2,3) phase change material

    NARCIS (Netherlands)

    Kooi, B.J.; de Hosson, J.T.M.

    2002-01-01

    The crystal structures of GeSb2Te4, Ge2Sb2Te5, and Ge3Sb2Te6 were determined using electron diffraction and high-resolution transmission electron microscopy. The structure determined for the former two crystals deviates from the ones proposed in the literature. These crystal structures were

  6. New Materials for High Temperature Thermoelectric Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Kauzlarich, Susan [Univ. of California, Davis, CA (United States)

    2016-02-03

    The scope of this proposal was to develop two new high ZT materials with enhanced properties for the n- and p-leg of a thermoelectric device capable of operating at a maximum temperature of 1275 K and to demonstrate the efficiency in a working device. Nanostructured composites and new materials based on n– and p–type nanostructured Si1-xGex (ZT1273K ~ 1) and the recently discovered p–type high temperature Zintl phase material, Yb14MnSb11 (ZT1273K ~1) were developed and tested in a working device.

  7. Phase Change Material Systems for High Temperature Heat Storage.

    Science.gov (United States)

    Perraudin, David Y S; Binder, Selmar R; Rezaei, Ehsan; Ortonaa, Alberto; Haussener, Sophia

    2015-01-01

    Efficient, cost effective, and stable high-temperature heat storage material systems are important in applications such as high-temperature industrial processes (metal processing, cement and glass manufacturing, etc.), or electricity storage using advanced adiabatic compressed air energy storage. Incorporating phase change media into heat storage systems provides an advantage of storing and releasing heat at nearly constant temperature, allowing steady and optimized operation of the downstream processes. The choice of, and compatibility of materials and encapsulation for the phase change section is crucial, as these must guarantee good and stable performance and long lifetime at low cost. Detailed knowledge of the material properties and stability, and the coupled heat transfer, phase change, and fluid flow are required to allow for performance and lifetime predictions. We present coupled experimental-numerical techniques allowing prediction of the long-term performance of a phase change material-based high-temperature heat storage system. The experimental investigations focus on determination of material properties (melting temperature, heat of fusion, etc.) and phase change material and encapsulation interaction (stability, interface reactions, etc.). The computational investigations focus on an understanding of the multi-mode heat transfer, fluid flow, and phase change processes in order to design the material system for enhanced performance. The importance of both the experimental and numerical approaches is highlighted and we give an example of how both approaches can be complementarily used for the investigation of long-term performance.

  8. The hydrated electron and its reactions at high temperatures

    DEFF Research Database (Denmark)

    Christensen, Hilbert; Sehested, Knud

    1986-01-01

    The spectrum of the hydrated electron was determined in the temperature range 5-300 "C by using strongly alkaline solutions and high hydrogen pressure. At temperatures up to about 150 "C the temperature coefficients of E, and AE1/2 are -2.8 X and 2 X lo4 eV K-', respectively. E,, is the energy....... The rate constant of the second-order decay (2k) is (1.00 f 0.05) X 1O'O dm3 mol-] s-I at 20 "C, independent of pH. The activation energy of the reaction is 23 f 1 kJ mol-] (5.4 f 0.2 kcal mol-') at temperatures up to 150 "C. The decay at temperatures above 150 "C becomes slower with increasing...... the electron spectrum, half-width, or em& to any significant degree at ambient and higher temperatures. -Th e simplest mechanism capable of describing the kinetic data at various temperatures is the equilibrium e,; + e,; F-? (e22-)aq H2 where the dissociation reaction has a higher activation energy than...

  9. Advanced materials for high-temperature thermoelectric energy conversion

    Science.gov (United States)

    Vining, Cronin B.; Vandersande, Jan W.; Wood, Charles

    1992-01-01

    A number of refractory semiconductors are under study at the Jet Propulsion Laboratory for application in thermal to electric energy conversion for space power. The main thrust of the program is to improve or develop materials of high figure of merit and, therefore, high conversion efficiencies over a broad temperature range. Materials currently under investigation are represented by silicon-germanium alloys, lanthanum telluride, and boron carbide. The thermoelectric properties of each of these materials, and prospects for their further improvements, are discussed. Continued progress in thermoelectric materials technology can be expected to yield reliable space power systems with double to triple the efficiency of current state of the art systems.

  10. Sealing Materials for Use in Vacuum at High Temperatures

    Science.gov (United States)

    Pettit, Donald R.; Camarda, Charles J.; Lee Vaughn, Wallace

    2012-01-01

    Sealing materials that can be applied and left in place in vacuum over a wide range of temperatures (especially temperatures of a few thousand degrees Celsius) have been conceived and investigated for potential utility in repairing thermal-protection tiles on the space shuttles in orbit before returning to Earth. These materials are also adaptable to numerous terrestrial applications that involve vacuum processing and/or repair of structures that must withstand high temperatures. These materials can be formulated to have mechanical handling characteristics ranging from almost freely flowing liquid-like consistency through paste-like consistency to stiff puttylike consistency, and to retain these characteristics in vacuum until heated to high curing temperatures. A sealing material of this type can be formulated to be used in any of several different ways for example, to be impregnated into a high-temperature-fabric patch, impregnated into a high-temperature-fabric gasket for sealing a patch, applied under a patch, or applied alone in the manner of putty or wallboard compound. The sealing material must be formulated to be compatible with, and adhere to, the structural material(s) to be repaired. In general, the material consists of a vacuum-compatible liquid containing one or more dissolved compound(s) and/or mixed with suspended solid particles. Depending on the intended application, the liquid can be chosen to be of a compound that can remain in place in vacuum for a time long enough to be useful, and/or to evaporate or decompose in a controlled way to leave a useful solid residue behind. The evaporation rate is determined by proper choice of vapor pressure, application of heat, and/or application of ultraviolet light or other optical radiation. The liquid chosen for the original space shuttle application is a commercial silicone vacuum-pump oil.

  11. Packaging Technologies for High Temperature Electronics and Sensors

    Science.gov (United States)

    Chen, Liangyu; Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Spry, David J.; Meredith, Roger D.

    2013-01-01

    This paper reviews ceramic substrates and thick-film metallization based packaging technologies in development for 500degC silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chiplevel packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550degC. A 96% alumina based edge connector for a PCB level subsystem interconnection has also been demonstrated recently. The 96% alumina packaging system composed of chip-level packages and PCBs has been tested with high temperature SiC devices at 500degC for over 10,000 hours. In addition to tests in a laboratory environment, a SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE-7 suite to the International Space Station via a Shuttle mission. This packaged SiC transistor was successfully tested in orbit for eighteen months. A spark-plug type sensor package designed for high temperature SiC capacitive pressure sensors was developed. This sensor package combines the high temperature interconnection system with a commercial high temperature high pressure stainless steel seal gland (electrical feed-through). Test results of a packaged high temperature capacitive pressure sensor at 500degC are also discussed. In addition to the pressure sensor package, efforts for packaging high temperature SiC diode-based gas chemical sensors are in process.

  12. High Temperature Wireless Communication And Electronics For Harsh Environment Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Beheim, G. M.; Ponchak, G. E.; Chen, L.-Y

    2007-01-01

    In order for future aerospace propulsion systems to meet the increasing requirements for decreased maintenance, improved capability, and increased safety, the inclusion of intelligence into the propulsion system design and operation becomes necessary. These propulsion systems will have to incorporate technology that will monitor propulsion component conditions, analyze the incoming data, and modify operating parameters to optimize propulsion system operations. This implies the development of sensors, actuators, and electronics, with associated packaging, that will be able to operate under the harsh environments present in an engine. However, given the harsh environments inherent in propulsion systems, the development of engine-compatible electronics and sensors is not straightforward. The ability of a sensor system to operate in a given environment often depends as much on the technologies supporting the sensor element as the element itself. If the supporting technology cannot handle the application, then no matter how good the sensor is itself, the sensor system will fail. An example is high temperature environments where supporting technologies are often not capable of operation in engine conditions. Further, for every sensor going into an engine environment, i.e., for every new piece of hardware that improves the in-situ intelligence of the components, communication wires almost always must follow. The communication wires may be within or between parts, or from the engine to the controller. As more hardware is added, more wires, weight, complexity, and potential for unreliability is also introduced. Thus, wireless communication combined with in-situ processing of data would significantly improve the ability to include sensors into high temperature systems and thus lead toward more intelligent engine systems. NASA Glenn Research Center (GRC) is presently leading the development of electronics, communication systems, and sensors capable of prolonged stable

  13. Modeling high temperature materials behavior for structural analysis

    CERN Document Server

    Naumenko, Konstantin

    2016-01-01

    This monograph presents approaches to characterize inelastic behavior of materials and structures at high temperature. Starting from experimental observations, it discusses basic features of inelastic phenomena including creep, plasticity, relaxation, low cycle and thermal fatigue. The authors formulate constitutive equations to describe the inelastic response for the given states of stress and microstructure. They introduce evolution equations to capture hardening, recovery, softening, ageing and damage processes. Principles of continuum mechanics and thermodynamics are presented to provide a framework for the modeling materials behavior with the aim of structural analysis of high-temperature engineering components.

  14. Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

    Science.gov (United States)

    Schwarze, Gene E.; Niedra, Janis M.; Frasca, Albert J.; Wieserman, William R.

    1993-01-01

    The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the Civilian Space Technology Initiative (CSTI) high capacity power project are presented: (1) neutron, gamma ray, and temperature effects on power semiconductor switches, (2) temperature and frequency effects on soft magnetic materials; and (3) temperature effects on rare earth permanent magnets.

  15. Electron Beam Cured Epoxy Resin Composites for High Temperature Applications

    Science.gov (United States)

    Janke, Christopher J.; Dorsey, George F.; Havens, Stephen J.; Lopata, Vincent J.; Meador, Michael A.

    1997-01-01

    Electron beam curing of Polymer Matrix Composites (PMC's) is a nonthermal, nonautoclave curing process that has been demonstrated to be a cost effective and advantageous alternative to conventional thermal curing. Advantages of electron beam curing include: reduced manufacturing costs; significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvement in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance the electron beam curing of PMC technology. Over the last several years a significant amount of effort within the CRADA has been devoted to the development and optimization of resin systems and PMCs that match the performance of thermal cured composites. This highly successful materials development effort has resulted in a board family of high performance, electron beam curable cationic epoxy resin systems possessing a wide range of excellent processing and property profiles. Hundreds of resin systems, both toughened and untoughened, offering unlimited formulation and processing flexibility have been developed and evaluated in the CRADA program.

  16. Materials for the scavanging of hydrogen at high temperatures

    Science.gov (United States)

    Shepodd, Timothy J.; Phillip, Bradley L.

    1997-01-01

    A hydrogen getter composition comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compostions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases.

  17. Diverse electron-induced optical emissions from space observatory materials at low temperatures

    Science.gov (United States)

    Dennison, J. R.; Evans Jensen, Amberly; Wilson, Gregory; Dekany, Justin; Bowers, Charles W.; Meloy, Robert

    2013-09-01

    Electron irradiation experiments have investigated the diverse electron-induced optical and electrical signatures observed in ground-based tests of various space observatory materials at low temperature. Three types of light emission were observed: (i); long-duration cathodoluminescence which persisted as long as the electron beam was on (ii) short-duration (fiberglass-epoxy composites, and macroscopically-conductive carbon-loaded polyimides). We conclude that electron-induced optical emissions resulting from interactions between observatory materials and the space environment electron flux can, in specific circumstances, make significant contributions to the stray light background that could possibly adversely affect the performance of space-based observatories.

  18. Variations in erosive wear of metallic materials with temperature via the electron work function

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaochen; Yu, Bin [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); Yan, X.G. [School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China); Li, D.Y., E-mail: dongyang.li@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 (Canada); School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, Shanxi (China)

    2016-04-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  19. Selection of High Temperature Organic Materials for Future Stirling Convertors

    Science.gov (United States)

    Shin, Euy-Sik Eugene

    2017-01-01

    In the future higher temperature Stirling convertors for improved efficiency and performance, various high temperature organic materials have been demanded as essential components for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The higher temperature capabilities would also allow current state-of-the-art (SOA) convertors to be used in additional missions, particularly those that require a Venus flyby for a gravity assist. Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of comprehensive structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, o-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This paper presents results of the three-step candidate evaluation processes, their application limitations, and the final selection recommendations.

  20. High-resolution electron microscopy of advanced materials

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, T.E.; Kung, H.H.; Sickafus, K.E.; Gray, G.T. III; Field, R.D.; Smith, J.F. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1997-11-01

    This final report chronicles a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The High-Resolution Electron Microscopy Facility has doubled in size and tripled in quality since the beginning of the three-year period. The facility now includes a field-emission scanning electron microscope, a 100 kV field-emission scanning transmission electron microscope (FE-STEM), a 300 kV field-emission high-resolution transmission electron microscope (FE-HRTEM), and a 300 kV analytical transmission electron microscope. A new orientation imaging microscope is being installed. X-ray energy dispersive spectrometers for chemical analysis are available on all four microscopes; parallel electron energy loss spectrometers are operational on the FE-STEM and FE-HRTEM. These systems enable evaluation of local atomic bonding, as well as chemical composition in nanometer-scale regions. The FE-HRTEM has a point-to-point resolution of 1.6 {angstrom}, but the resolution can be pushed to its information limit of 1 {angstrom} by computer reconstruction of a focal series of images. HRTEM has been used to image the atomic structure of defects such as dislocations, grain boundaries, and interfaces in a variety of materials from superconductors and ferroelectrics to structural ceramics and intermetallics.

  1. Refractory materials for high-temperature thermoelectric energy conversion

    Science.gov (United States)

    Wood, C.; Emin, D.

    1984-01-01

    Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant contributions involved the estimaiation of optimum doping concentrations, the reduction of thermal conductivity by solid solution doping and the development of a variety of materials with ZT approx. 1 in the temperature range 300 K to 1200 K. ZT approx. 1 is not a theoretical limitation although, experimentally, values in excess of one were not achieved. Work has continued with emphasis on higher temperature energy conversion. A number of promising materials have been discovered in which it appears that ZT 1 is realizable. These materials are divided into two classes: (1) the rare-earth chalcogenides which behave as itinerant highly-degenerate n-type semiconductors at room-temperature, and (2) the boron-rich borides, which exhibit p-type small-polaronic hopping conductivity.

  2. Refractory materials for high-temperature thermoelectric energy conversion

    Energy Technology Data Exchange (ETDEWEB)

    Wood, C.; Emin, D.

    1983-01-01

    Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant contributions involved the estimation of optimum doping concentrations, the reduction of thermal conductivity by solid solution doping and the development of a variety of materials with ZT approx. 1 in the temperature range 300 K to 1200 K. It was also shown that ZT approx. 1 is not a theoretical limitation although, experimentally, values in excess of one were not achieved. Work has continued with emphasis on higher temperature energy conversion. A number of promising materials have been discovered in which it appears that ZT > 1 is realizable. These materials can be divided into two classes: (i) the rare-earth chalcogenides, which behave as itinerant highly-degenerate n-type semiconductors at room-temperature, and (ii) the boron-rich borides, which exhibit p-type small-polaronic hopping conductivity.

  3. Novel High Temperature Materials for In-Situ Sensing Devices

    Energy Technology Data Exchange (ETDEWEB)

    Florian Solzbacher; Anil Virkar; Loren Rieth; Srinivasan Kannan; Xiaoxin Chen; Hannwelm Steinebach

    2009-12-31

    The overriding goal of this project was to develop gas sensor materials and systems compatible with operation at temperatures from 500 to 700 C. Gas sensors operating at these temperatures would be compatible with placement in fossil-energy exhaust streams close to the combustion chamber, and therefore have advantages for process regulation, and feedback for emissions controls. The three thrusts of our work included investigating thin film gas sensor materials based on metal oxide materials and electroceramic materials, and also development of microhotplate devices to support the gas sensing films. The metal oxide materials NiO, In{sub 2}O{sub 3}, and Ga{sub 2}O{sub 3} were investigated for their sensitivity to H{sub 2}, NO{sub x}, and CO{sub 2}, respectively, at high temperatures (T > 500 C), where the sensing properties of these materials have received little attention. New ground was broken in achieving excellent gas sensor responses (>10) for temperatures up to 600 C for NiO and In{sub 2}O{sub 3} materials. The gas sensitivity of these materials was decreasing as temperatures increased above 500 C, which indicates that achieving strong sensitivities with these materials at very high temperatures (T {ge} 650 C) will be a further challenge. The sensitivity, selectivity, stability, and reliability of these materials were investigated across a wide range of deposition conditions, temperatures, film thickness, as using surface active promoter materials. We also proposed to study the electroceramic materials BaZr{sub (1-x)}Y{sub x}O{sub (3-x/2)} and BaCe{sub (2-x)}Ca{sub x}S{sub (4-x/2)} for their ability to detect H{sub 2}O and H{sub 2}S, respectively. This report focuses on the properties and gas sensing characteristics of BaZr{sub (1-x)}Y{sub x}O{sub (3-x/2)} (Y-doped BaZrO{sub 3}), as significant difficulties were encounter in generating BaCe{sub (2-x)}Ca{sub x}S{sub (4-x/2)} sensors. Significant new results were achieved for Y-doped BaZrO{sub 3}, including

  4. Screening of High Temperature Organic Materials for Future Stirling Convertors

    Science.gov (United States)

    Shin, Euy-sik E.; Scheiman, Daniel A.

    2017-01-01

    Along with major advancement of Stirling-based convertors, high temperature organics are needed to develop future higher temperature convertors for much improved efficiencies as well as to improve the margin of reliability for the current SOA (State-of-the-Art) convertors. The higher temperature capabilities would improve robustness of the convertors and also allow them to be used in additional missions, particularly ones that require a Venus flyby for a gravity assist. Various organic materials have been employed as essential components in the convertor for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of every possible material structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, O-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This report presents results of the three-step candidate evaluation processes, their application limitations, and the final selection

  5. Packaging Technology Developed for High-Temperature SiC Sensors and Electronics

    Science.gov (United States)

    Chen, Liang-Yu; Hunter, Gary W.; Neudeck, Philip G.; Lei, Jih-Fen

    2000-01-01

    A ceramic- and thick-film-materials-based prototype electronic package designed for silicon carbide (SiC) high-temperature sensors and electronics has been successfully tested at 500 C in an oxygen-containing air environment for 500 hours. This package was designed, fabricated, assembled, and electronically evaluated at the NASA Glenn Research Center at Lewis Field with an in-house-fabricated SiC semiconductor test chip. High-temperature electronics and sensors are necessary for harsh-environment space and aeronautical applications, such as space missions to the inner solar system or the emission control electronics and sensors in aeronautical engines. Single-crystal SiC has such excellent physical and chemical material properties that SiC-based semiconductor electronics can operate at temperatures over 600 C, which is significantly higher than the limit for Si-based semiconductor devices. SiC semiconductor chips were recently demonstrated to be operable at temperatures as high as 600 C, but only in the probe station environment because suitable packaging technology for sensors and electronics at temperatures of 500 C and beyond did not exist. Thus, packaging technology for SiC-based sensors and electronics is immediately needed for both application and commercialization of high-temperature SiC sensors and electronics. In response to this need, researchers at Glenn designed, fabricated, and assembled a prototype electronic package for high-temperature electronics, sensors, and microelectromechanical systems (MEMS) using aluminum nitride (AlN) substrate and gold (Au) thick-film materials. This prototype package successfully survived a soak test at 500 C in air for 500 hours. Packaging components tested included thick-film high-temperature metallization, internal wire bonds, external lead bonds, and a SiC diode chip die-attachment. Each test loop, which was composed of thick-film printed wire, wire bond, and lead bond was subjected to a 50-mA direct current for 250

  6. High Temperature Pt/Alumina Co-Fired System for 500 C Electronic Packaging Applications

    Science.gov (United States)

    Chen, Liang-Yu; Neudeck, Philip G.; Spry, David J.; Beheim, Glenn M.; Hunter, Gary W.

    2015-01-01

    Gold thick-film metallization and 96 alumina substrate based prototype packaging system developed for 500C SiC electronics and sensors is briefly reviewed, the needs of improvement are discussed. A high temperature co-fired alumina material system based packaging system composed of 32-pin chip-level package and printed circuit board is discussed for packaging 500C SiC electronics and sensors.

  7. Corrosion behaviour of construction materials for high temperature steam electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik

    2011-01-01

    Different types of commercially available stainless steels, Ni-based alloys as well as titanium and tantalum were evaluated as possible metallic bipolar plates and construction materials. The corrosion resistance was measured under simulated conditions corresponding to the conditions in high...... to corrosion under strong anodic polarisation. Among alloys, Ni-based showed the highest corrosion resistance in the simulated PEM electrolyser medium. In particular, Inconel 625 was the most promising among the tested corrosion-resistant alloys for the anodic compartment in high temperature steam electrolysis...

  8. High Temperature Thermoelectric Properties of ZnO Based Materials

    DEFF Research Database (Denmark)

    Han, Li

    This thesis investigated the high temperature thermoelectric properties of ZnO based materials. The investigation first focused on the doping mechanisms of Al-doped ZnO, and then the influence of spark plasma sintering conditions on the thermoelectric properties of Al, Ga-dually doped ZnO....... Following that, the nanostructuring effect for Al-doped ZnO was systematically investigated using samples with different microstructure morphologies. At last, the newly developed ZnCdO materials with superior thermoelectric properties and thermal stability were introduced as promising substitutions...... for conventional ZnO materials. For Al-doped ZnO, α- and γ-Al2O3 were selectively used as dopants in order to understand the doping mechanism of each phase and their effects on the thermoelectric properties. The samples were prepared by the spark plasma sintering technique from precursors calcined at various...

  9. Materials for the scavenging of hydrogen at high temperatures

    Science.gov (United States)

    Shepodd, T.J.; Phillip, B.L.

    1997-04-29

    A hydrogen getter composition is described comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compositions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluoropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases. 7 figs.

  10. Multiyear Program Plan for the High Temperature Materials Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Arvid E. Pasto

    2000-03-17

    Recently, the U.S. Department of Energy's (DOE) Office of Heavy Vehicle Technologies (OHVT) prepared a Technology Roadmap describing the challenges facing development of higher fuel efficiency, less polluting sport utility vehicles, vans, and commercial trucks. Based on this roadmap, a multiyear program plan (MYPP) was also developed, in which approaches to solving the numerous challenges are enumerated. Additional planning has been performed by DOE and national laboratory staff, on approaches to solving the numerous challenges faced by heavy vehicle system improvements. Workshops and planning documents have been developed concerning advanced aerodynamics, frictional and other parasitic losses, and thermal management. Similarly, the Heavy Vehicle Propulsion Materials Program has developed its own multiyear program plan. The High Temperature Materials Laboratory, a major user facility sponsored by OHVT, has now developed its program plan, described herein. Information was gathered via participation in the development of OHVT's overall Technology Roadmap and MYPP, through personal contacts within the materials-user community, and from attendance at conferences and expositions. Major materials issues for the heavy vehicle industry currently center on trying to increase efficiency of (diesel) engines while at the same time reducing emissions (particularly NO{sub x} and particulates). These requirements dictate the use of increasingly stronger, higher-temperature capable and more corrosion-resistant materials of construction, as well as advanced catalysts, particulate traps, and other pollution-control devices. Exhaust gas recirculation (EGR) is a technique which will certainly be applied to diesel engines in the near future, and its use represents a formidable challenge, as will be described later. Energy-efficient, low cost materials processing methods and surface treatments to improve wear, fracture, and corrosion resistance are also required.

  11. Thermal Expansion Studies of Selected High Temperature Thermoelectric Materials

    Science.gov (United States)

    Ravi, Vilupanur; Firdosy, Samad; Caillat, Thierry; Brandon, Erik; Van Der Walde, Keith; Maricic, Lina; Sayir, Ali

    2008-01-01

    Radioisotope thermoelectric generators (RTGs) generate electrical power by converting the heat released from the nuclear decay of radioactive isotopes (typically plutonium-238) into electricity using a thermoelectric converter. RTGs have been successfully used to power a number of space missions and have demonstrated their reliability over an extended period of time (tens of years) and are compact, rugged, radiation resistant, scalable, and produce no noise, vibration or torque during operation. System conversion efficiency for state-of-practice RTGs is about 6% and specific power less than or equal to 5.1 W/kg. Higher specific power would result in more on-board power for the same RTG mass, or less RTG mass for the same on-board power. The Jet Propulsion Laboratory has been leading, under the advanced thermoelectric converter (ATEC) project, the development of new high-temperature thermoelectric materials and components for integration into advanced, more efficient RTGs. Thermoelectric materials investigated to date include skutterudites, the Yb14MnSb11 compound, and SiGe alloys. The development of long-lived thermoelectric couples based on some of these materials has been initiated and is assisted by a thermo-mechanical stress analysis to ensure that all stresses under both fabrication and operation conditions will be within yield limits for those materials. Several physical parameters are needed as input to this analysis. Among those parameters, the coefficient of thermal expansion (CTE) is critically important. Thermal expansion coefficient measurements of several thermoelectric materials under consideration for ATEC are described in this paper. The stress response at the interfaces in material stacks subjected to changes in temperature is discussed, drawing on work from the literature and project-specific tools developed here. The degree of CTE mismatch and the associated effect on the formation of stress is highlighted.

  12. Electron Temperatures in W51 Complex from High Resolution, Low ...

    Indian Academy of Sciences (India)

    2001-03-09

    Mar 9, 2001 ... All the RRL results quoted above have been derived under the LTE approximation. The electron temperature is one of the most important parameters in understanding the physical properties of thermal HII regions. Low frequency continuum observations in the optically thick regime offer a direct estimate of ...

  13. Electronic and Magnetic Properties of High Temperature Electrolytes.

    Science.gov (United States)

    Measurements are reported on the electrical conductance in the Cs-CsCl and Rb- RbCl molten systems as a function of composition and temperature. The...in salt are evaluated from freezing point data, and are large and positive for the Cs-CsCl and Rb- RbCl systems. Electron spin resonance has been

  14. Improved Materials for High-Temperature Black Liquor Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Keiser, J.R.; Hemrick, J.G.; Gorog, J.P.; Leary, R.

    2006-06-29

    The laboratory immersion test system built and operated at ORNL was found to successfully screen samples from numerous refractory suppliers, including both commercially available and experimental materials. This system was found to provide an accurate prediction of how these materials would perform in the actual gasifier environment. Test materials included mullites, alumino-silicate bricks, fusion-cast aluminas, alumina-based and chrome-containing mortars, phosphate-bonded mortars, coated samples provided under an MPLUS-funded project, bonded spinels, different fusion-cast magnesia-alumina spinels with magnesia content ranging from 2.5% to about 60%, high-MgO castable and brick materials, spinel castables, and alkali-aluminate materials. This testing identified several candidate material systems that perform well in the New Bern gasifier. Fusion-cast aluminas were found to survive for nearly one year, and magnesia-alumina spinels have operated successfully for 18 months and are expected to survive for two years. Alkali-aluminates and high-MgO-content materials have also been identified for backup lining applications. No other material with a similar structure and chemical composition to that of the fusion-cast magnesium-aluminum spinel brick currently being used for the hot-face lining is commercially available. Other materials used for this application have been found to have inferior service lives, as previously discussed. Further, over 100 laboratory immersion tests have been performed on other materials (both commercial and experimental), but none to date has performed as well as the material currently being used for the hot-face lining. Operating experience accumulated with the high-temperature gasifier at New Bern, North Carolina, has confirmed that the molten alkali salts degrade many types of refractories. Fusion-cast alumina materials were shown to provide a great improvement in lifetime over materials used previously. Further improvement was realized

  15. WS2 as an excellent high-temperature thermoelectric material

    KAUST Repository

    Gandi, Appala

    2014-11-25

    The potential of WS2 as a thermoelectric material is assessed. The electronic contribution to the thermoelectric properties is calculated within the constant relaxation time approximation from the electronic band structure, whereas the lattice contribution is evaluated using self-consistently calculated phonon lifetimes. In addition, the dependence of the lattice thermal conductivity on the mean free path of the phonons is determined.

  16. Materials, structures, and devices for high-speed electronics

    Science.gov (United States)

    Woollam, John A.; Snyder, Paul G.

    1992-01-01

    Advances in materials, devices, and instrumentation made under this grant began with ex-situ null ellipsometric measurements of simple dielectric films on bulk substrates. Today highly automated and rapid spectroscopic ellipsometers are used for ex-situ characterization of very complex multilayer epitaxial structures. Even more impressive is the in-situ capability, not only for characterization but also for the actual control of the growth and etching of epitaxial layers. Spectroscopic ellipsometry has expanded from the research lab to become an integral part of the production of materials and structures for state of the art high speed devices. Along the way, it has contributed much to our understanding of the growth characteristics and material properties. The following areas of research are summarized: Si3N4 on GaAs, null ellipsometry; diamondlike carbon films; variable angle spectroscopic ellipsometry (VASE) development; GaAs-AlGaAs heterostructures; Ta-Cu diffusion barrier films on GaAs; GaAs-AlGaAs superlattices and multiple quantum wells; superconductivity; in situ elevated temperature measurements of III-V's; optical constants of thermodynamically stable InGaAs; doping dependence of optical constants of GaAs; in situ ellipsometric studies of III-V epitaxial growth; photothermal spectroscopy; microellipsometry; and Si passivation and Si/SiGe strained-layer superlattices.

  17. High Temperature Stable Nanocrystalline SiGe Thermoelectric Material

    Science.gov (United States)

    Yang, Sherwin (Inventor); Matejczyk, Daniel Edward (Inventor); Determan, William (Inventor)

    2013-01-01

    A method of forming a nanocomposite thermoelectric material having microstructural stability at temperatures greater than 1000 C. The method includes creating nanocrystalline powder by cryomilling. The method is particularly useful in forming SiGe alloy powder.

  18. Improved Creep Measurements for Ultra-High Temperature Materials

    Science.gov (United States)

    Hyers, Robert W.; Ye, X.; Rogers, Jan R.

    2010-01-01

    Our team has developed a novel approach to measuring creep at extremely high temperatures using electrostatic levitation (ESL). This method has been demonstrated on niobium up to 2300 C, while ESL has melted tungsten (3400 C). This method has been extended to lower temperatures and higher stresses and applied to new materials, including a niobium-based superalloy, MASC. High-precision machined spheres of the sample are levitated in the NASA MSFC ESL, a national user facility and heated with a laser. The samples are rotated with an induction motor at up to 30,000 revolutions per second. The rapid rotation loads the sample through centripetal acceleration, producing a shear stress of about 60 MPa at the center, causing the sample to deform. The deformation of the sample is captured on high-speed video, which is analyzed by machine-vision software from the University of Massachusetts. The deformations are compared to finite element models to determine the constitutive constants in the creep relation. Furthermore, the non-contact method exploits stress gradients within the sample to determine the stress exponent in a single test.

  19. Evaluation of fundamental properties of filter materials at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, Y.; Hiramatsu, K.; Kawamoto, H. [Japan Fine Ceramics Center, Nagoya (Japan); Araki, T. [Chubu Electric Power Co., Inc., Hekinan (Japan); Yamada, M.; Iida, J. [Center For Coal Utilization Japan, Tokyo (Japan)

    1999-07-01

    In developing a dust collecting technology for high-temperature coal combustion gases for use in a next-generation system of efficient power generation, it is important to raise reliability by ascertaining the relevant physical properties and behaviors of the dust collecting filters. Accordingly, the aim of this research is to clarify the mechanical and thermal properties, and the high-temperature corrosion behaviors (oxidization, reduction), which figure among the fundamental factors restricting reliability in filter materials. In addition, since the ultimate research aim is the selection and development of filters which can be used in the actual dust collecting systems PFBC (950 C in an oxidization atmosphere) and IGCC (700 C in a reduction atmosphere), it is also necessary to conduct tests on the fundamental properties of existing filters, and to classify them for their suitability with given service atmospheres. Finally, for one particular filter selected as suitable for an oxidation atmosphere of 950 C, observations are made of mechanical properties and micro-structural changes before and after an actual dust collecting trial, and cause of damage are investigated. (orig.)

  20. Using IDA to Understand Electron Temperature Structures in High Temperature Discharges in the Madison Symmetric Torus

    Science.gov (United States)

    Reusch, L. M.; Galante, M. E.; den Hartog, D. J.; Franz, P.; Johnson, J. R.; McGarry, M. B.; Stephens, H. D.

    2014-10-01

    The Madison Symmetric Torus (MST) Reversed-Field Pinch is equipped with two independent electron temperature (Te) diagnostics: Thomson scattering (TS) and double-filter soft x-ray (SXR). Both diagnostics are able to measure Te at a rate up to 25 kHz and are in good qualitative agreement in the hot plasma core, where Te > 1 keV. We are able to combine information from both TS and SXR diagnostics along with prior physics knowledge using integrated data analysis techniques (IDA) [R. Fischer and A. Dinklage, Rev. Sci. Instrum. 75, 4237 (2004)] to improve the precision and utility of Te measurements on MST. Using IDA, there is a factor of 4 improvement in the uncertainty of all temperature measurements. We have also implemented a Markov Chain Monte Carlo analysis for analyzing the various temperature structures that MST is capable of sustaining. We have compared emissivity maps and flux surface reconstructions to the electron temperatures from several discharges to characterize the phenomenology of temperature structures in high temperature plasmas in MST. Work supported by US DOE and NSF.

  1. New Oxide Materials for an Ultra High Temperature Environment

    Energy Technology Data Exchange (ETDEWEB)

    Perepezko, John H. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering

    2017-11-13

    In this project, a new oxide material, Hf6Ta2O17 has been successfully synthesized by the controlled oxidization of Hf-Ta alloys. This oxide exhibits good oxidation resistance, high temperature phase stability up to more than 2000°C, low thermal conductivity and thus could serve as a component or a coating material in an ultrahigh temperature environment. We have examined the microstructure evolution and phase formation sequence during the oxidation exposure of Hf-Ta alloys at 1500°C and identified that the oxidation of a Hf-26.7atomic %Ta alloy leads to the formation of a single phase adherent Hf6Ta2O17 with a complex atomic structure i.e. superstructure. The overall reactive diffusion pathway is consistent with the calculated Hf-Ta-O ternary phase diagram. Besides the synthesis of Hf6Ta2O17 superstructure by oxidizing Hf-Ta alloys, we have also developed a synthesis method based upon the reactive sintering of the correct ratios of mixed powders of HfO2 and Ta2O5 and verified the low thermal conductivity of Hf6Ta2O17 superstructure on these samples. We have completed a preliminary analysis of the oxidation kinetics for Hf6Ta2O17, which shows an initial parabolic oxidation kinetics.

  2. Phonons, electronic charge response and electron-phonon interaction in the high-temperature superconductors

    Science.gov (United States)

    Falter, Claus

    2005-01-01

    We investigate the complete phonon dispersion, the phonon induced electronic charge response and the corresponding self-consistent change of the crystal potential an electron feels as a direct measure of the electron-phonon interaction in the high-temperature superconductors within a microscopic model in the framework of linear response theory. Moreover, dielectric and infrared properties are calculated. The experimentally observed strong renormalization of the in-plane oxygen bond-stretching modes which appears upon doping in the high-temperature superconductors is discussed. It is shown that the characteristic softening, indicating a strong nonlocal electron-phonon interaction, is most likely a generic effect of the CuO plane and is driven by a nonlocal coupling of the displaced ions to the localized charge-fluctuations at the Cu and the Oxy ions. At hand of the oxygen bond-stretching modes it is illustrated how lattice-, charge- and spin-degrees of freedom may act synergetically for anisotropic pairing in the high-temperature superconductors. The different behaviour of these modes during the insulator-metal transition via the underdoped phase is calculated and from a comparison of these generic modes in the different phases conclusions about the electronic state are drawn. For the non-cuprate potassium doped high-temperature superconductor Ba-Bi-O also a very strong and anisotropic renormalization of the oxygen bond-stretching modes is predicted. In another investigation c-axis polarized infrared- and Raman-active modes of the HTSC's are calculated in terms of charge fluctuations and anisotropic dipole-fluctuations. Mode assignments discussed controversially in the literature are proposed. Finally, interlayer phonons propagating along the c-axis and their accompanying charge response are investigated. Depending on the strength of the interlayer coupling calculations are performed ranging from the static, adiabatic response regime to the non-adiabatic regime

  3. Electronic materials

    CERN Document Server

    Kwok, H L

    2010-01-01

    The electronic properties of solids have become of increasing importance in the age of information technology. The study of solids and materials, while having originated from the disciplines of physics and chemistry, has evolved independently over the past few decades. The classical treatment of solid-state physics, which emphasized classifications, theories and fundamental physical principles, is no longer able to bridge the gap between materials advances and applications. In particular, the more recent developments in device physics and technology have not necessarily been driven by new conc

  4. The Development of High Temperature Thermoplastic Composite Materials for Additive Manufactured Autoclave Tooling

    Energy Technology Data Exchange (ETDEWEB)

    Kunc, Vlastimil [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lindahl, John M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hassen, Ahmed A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    In this work, ORNL and Techmer investigated and screened different high temperature thermoplastic reinforced materials to fabricate composite molds for autoclave processes using Additive Manufacturing (AM) techniques. This project directly led to the development and commercial release of two printable, high temperature composite materials available through Techmer PM. These new materials are targeted for high temperature tooling made via large scale additive manufacturing.

  5. High temperature corrosion of separator materials for MCFC

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Masahiro; Tanimoto, Kazumi; Kojima, Toshikatsu [Osaka National Research Institute (Japan)] [and others

    1996-12-31

    The Molten Carbonate Fuel Cell (MCFC) is one of promising high efficiency power generation devices with low emission. Molten carbonate used for its electrolyte plays an important role in MCFC. It separates between anode and cathode gas environment and provides ionic conductivity on MCFC operation. Stainless steel is conventionally used as separator/current collector materials in MCFC cathode environment. As corrosion of the components of MCFC caused by the electrolyte proceeds with the electrolyte consumption, the corrosion in the MCFC is related to its performance and life. To understand and inhibit the corrosion in the MCFC is important to realize MCFC power generation system. We have studied the effect of alkaline earth carbonate addition into carbonate on corrosion of type 316L stainless steel. In this paper, we describe the effect of the temperature on corrosion behavior of type 316L stainless steel with carbonate mixture, (Li{sub 0.62}K{sub 0.38}){sub 2}CO{sub 3}, under the cathode environment in out-of-cell test.

  6. Combustion and Plasma Synthesis of High-Temperature Materials

    Science.gov (United States)

    Munir, Z. A.; Holt, J. B.

    1997-04-01

    KEYNOTE ADDRESS. Self-Propagating High-Temperature Synthesis: Twenty Years of Search and Findings (A. Merzhanov). SOLID-STATE COMBUSTION SYNTHESIS. Recent Progress in Combustion Synthesis of High-Performance Materials in Japan (M. Koizumi & Y. Miyamoto). Modeling and Numerical Computation of a Nonsteady SHS Process (A. Bayliss & B. Matkowsky). New Models of Quasiperiodic Burning in Combustion Synthesis (S. Margolis, et al.). Modeling of SHS Operations (V. Hlavacek, et al.). Combustion Theory for Sandwiches of Alloyable Materials (R. Armstrong & M. Koszykowski). Observations on the Combustion Reaction Between Thin Foils of Ni and Al (U. Anselmi-Tamburini & Z. Munir). Combustion Synthesis of Intermetallic Compounds (Y. Kaieda, et al.). Combustion Synthesis of Nickel Aluminides (B. Rabin, et al.). Self-Propagating High-Temperature Synthesis of NiTi Intermetallics (H. Yi & J. Moore). Shock-Induced Chemical Synthesis of Intermetallic Compounds (S. Work, et al.). Advanced Ceramics Via SHS (T. DeAngelis & D. Weiss). In-Situ Formation of SiC and SiC-C Blocked Solids by Self-Combustion Synthesis (S. Ikeda, et al.). Powder Purity and Morphology Effects in Combustion-Synthesis Reactions (L. Kecskes, et al.). Simultaneous Synthesis and Densification of Ceramic Components Under Gas Pressure by SHS (Y. Miyamoto & M. Koizumi). The Use of Self-Propagating High-Temperature Synthesis of High-Density Titanium Diboride (P. Zavitsanos, et al.). Metal--Ceramic Composite Pipes Produced by a Centrifugal-Thermit Process (O. Odawara). Simultaneous Combustion Synthesis and Densification of AIN (S. Dunmead, et al.). Fabrication of a Functionally Gradient Material by Using a Self-Propagating Reaction Process (N. Sata, et al.). Combustion Synthesis of Oxide-Carbide Composites (L. Wang, et al.). Heterogeneous Reaction Mechanisms in the Si-C System Under Conditions of Solid Combustion (R. Pampuch, et al.). Experimental Modeling of Particle-Particle Interactions During SHS of TiB2 -Al2O3 (K. Logan

  7. Physics and Materials Science of High Temperature Superconductors

    Science.gov (United States)

    1989-08-26

    SUPERCONDUCTIVITY OF BULK HIGH TEMPERATURE SUPERCONDUCTORS. F. M. Costa and J. M. Vieira, Departamento de Eng. Ceramica e de Vidro, Universidade de Aveiro...Lisboa, Portugal; F. Costa, Dep Eng Ceramica e do Vidro, Universidade de Aveiro, P-3800 Avaerio, Portugal; and J. M. Alves and M. M. Godinho, Dep Fisica

  8. Engineering Materials for Very High Temperatures: An ONRL Workshop

    Science.gov (United States)

    1988-08-29

    high temperature, time-dependent strength of hot isostatically pressed (HIP’ed) Y-TZP (Swab, Katz, & Starita , 1987). In this instance a commercially...12, p-137-14 6. Swab, J, Katz, R. N. & Starita , C., (1987), unpublished research. Tracy, C. & Slavin, M. J., (1927), Presented at 89th annual meeting

  9. 9 Cr-- 1 Mo steel material for high temperature application

    Science.gov (United States)

    Jablonski, Paul D; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-11-27

    One or more embodiments relates to a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The 9 Cr-1 Mo steel has a tempered martensite microstructure and is comprised of both large (0.5-3 .mu.m) primary titanium carbides and small (5-50 nm) secondary titanium carbides in a ratio of. from about 1:1.5 to about 1.5:1. The 9 Cr-1 Mo steel may be fabricated using exemplary austenizing, rapid cooling, and tempering steps without subsequent hot working requirements. The 9 Cr-1 Mo steel exhibits improvements in total mass gain, yield strength, and time-to-rupture over ASTM P91 and ASTM P92 at the temperature and time conditions examined.

  10. High-Temperature Electronics: Status and Future Prospects in the 21st Century

    Directory of Open Access Journals (Sweden)

    F. Touati

    2006-12-01

    Full Text Available This paper reviews the state of current electronics and states the drive toward high-temperature electronics. The problems specific to high-temperature effects on conventional electronics and prospects of alternative technologies like silicon-on-insulator, silicon carbide, and diamond are discussed. Improving petroleum recovery from oil wells with hightemperature coverage of downhole electronics, making combustion processes more efficient utilizing embedded electronics, programs for More Electric Aircraft and Vehicles necessitating distributed control systems, and environmental protection issues stress the need to use and develop high-temperature electronics. This makes high-temperature electronics a key-enabling technology in the 21st century. Actual applications using high-temperature electronics are discussed in some details. Also information and guidelines are included about supporting electronics needed to make a complete high-temperature system. The technology has been making major advancements and is expected to account for 20% of the electronics market by 2010. However, many technical challenges have to be solved.

  11. Investigation of medium and high temperature phase change materials

    Science.gov (United States)

    Heine, D.; Kraehling, H.

    1979-01-01

    A detailed description of the programs for acquisition and analysis of the test results is given. Basically it concerns three programs. The TEST program controls the recording of the test data. With the THELLI program it is possible to follow the temperature curve recorded for each individual thermoelement during the test. With the AUSW program the test data can be analyzed, to determine, for example, the melting point and the start of melting. The first results of the service life tests are discussed. From these it is attempted to draw inferences for the subsequent tests. An attempt is made to focus on the determination of the area-related mass loss, the reduction in thickness and the corrosion rate as well as optical and scanning electron microscope evaluation.

  12. An insertion to eliminate horizontal temperature of high energy electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Burov, A.V. [AN SSSR, Novosibirsk (Russian Federation). Inst. Yadernoj Fiziki; Danilov, V.V. [AN SSSR, Novosibirsk (Russian Federation). Inst. Yadernoj Fiziki

    1998-03-16

    High energy electron cooling with a circulated electron bunch could significantly increase the luminosity of hadron colliders. One of the significant obstacles is high horizontal temperature of electron bunches, suppressing dramatically calculated cooling rates. Recently, a transformation of betatron coordinates and angles for elimination of the radial temperature was found. In our paper, we present a simple scheme to make up this transformation by thin quadruples, drifts and a solenoid.

  13. High Bismuth Alloys as Lead-Free Alternatives for Interconnects in High-Temperature Electronics

    Science.gov (United States)

    Mallampati, Sandeep

    Predominant high melting point solders for high-temperature electronics (operating temperatures from 200 to 250°C) are Pb-based which are being banned from usage due to their toxic nature. In this study, high bismuth alloy compositions (Bi-14Cu-8Sn, Bi-20Sb-10Cu, Bi-15Sb-10Cu and Bi-10Sb-10Cu) were designed, cast, and characterized to understand their potential as replacements. The desirable aspect of Bi is its high melting temperature, which is 271°C. Alloying elements Sn, Sb and Cu were added to improve some of its properties such as thermal conductivity, plasticity, and reactivity with Cu and Ni surface. Metallographic sectioning and microstructure analysis were performed on the bulk alloys to compare the evolution of phases predicted from equilibrium phase diagrams. Reflow processes were developed to make die-attach samples out of the proposed alloys and die-shear testing was carried out to characterize mechanical integrity of the joint. Thermal shock between -55°C to 200°C and high temperature storage at 200°C were performed on the assembled die-attach samples to study microstructure evolution and mechanical behavior of the reflowed alloys under accelerated testing conditions. In addition, heat dissipation capabilities, using flash diffusivity, were measured on the bulk alloys and also on the die-attach assembly. Finally, tensile testing was performed on the dogbone specimens to identify the potential for plastic deformation and electron backscatter diffraction (EBSD) analysis was used to study the grain orientations on the fracture surfaces and their influence on the crack propagation. Bi-14Cu-8Sn has formed BiNi by on the die backside metallization and the reaction with Cu was poor. This has resulted in weaker substrate side interface. It was observed that Bi-Sb alloys have strong reactivity with Ni (forming Bi3Ni, BiNi and NiSb intermetallic phases), and with Cu (forming Cu2Sb, Cu4Sb). Spallation was observed in NiSb interfacial intermetallic layer and

  14. Generation IV Reactors Integrated Materials Technology Program Plan: Focus on Very High Temperature Reactor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, William R [ORNL; Burchell, Timothy D [ORNL; Katoh, Yutai [ORNL; McGreevy, Timothy E [ORNL; Nanstad, Randy K [ORNL; Ren, Weiju [ORNL; Snead, Lance Lewis [ORNL; Wilson, Dane F [ORNL

    2008-08-01

    the structural materials needed to ensure their safe and reliable operation. The focus of this document will be the overall range of DOE's structural materials research activities being conducted to support VHTR development. By far, the largest portion of material's R&D supporting VHTR development is that being performed directly as part of the Next-Generation Nuclear Plant (NGNP) Project. Supplementary VHTR materials R&D being performed in the DOE program, including university and international research programs and that being performed under direct contracts with the American Society for Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, will also be described. Specific areas of high-priority materials research that will be needed to deploy the NGNP and provide a basis for subsequent VHTRs are described, including the following: (1) Graphite: (a) Extensive unirradiated materials characterization and assessment of irradiation effects on properties must be performed to qualify new grades of graphite for nuclear service, including thermo-physical and mechanical properties and their changes, statistical variations from billot-to-billot and lot-to-lot, creep, and especially, irradiation creep. (b) Predictive models, as well as codification of the requirements and design methods for graphite core supports, must be developed to provide a basis for licensing. (2) Ceramics: Both fibrous and load-bearing ceramics must be qualified for environmental and radiation service as insulating materials. (3) Ceramic Composites: Carbon-carbon and SiC-SiC composites must be qualified for specialized usage in selected high-temperature components, such as core stabilizers, control rods, and insulating covers and ducting. This will require development of component-specific designs and fabrication processes, materials characterization, assessment of environmental and irradiation effects, and establishment of codes and standards for materials testing and design

  15. Titanium nitride as a refractory plasmonic material for high temperature applications

    DEFF Research Database (Denmark)

    Guler, Urcan; Li, Wen-Wei; Boltasseva, Alexandra

    2014-01-01

    The use of titanium nitride as a plasmonic material for high temperature applications such as solar/thermophotovoltaics is studied numerically and experimentally. Performance of titanium nitride is compared with widely used materials in each field. © 2014 OSA....

  16. Carbon materials derived from rice husks at low and high temperatures

    Science.gov (United States)

    Melvin, G. J. H.; Wang, Z.; Siambun, N. J.; Rahman, M. M.

    2017-07-01

    Rice husk (RH) can be classified as an agriculture residue, majorly produced from by-product of rice milling industries. However, RHs are only mainly utilized for low value energy resource. A great number of researches and innovations have shown that heat treated RHs can turn into valuable carbon materials. In this study, the RHs were carbonized at 800°C and 2500°C, respectively. Their structure, morphology, elemental composition, and quality were characterized using transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The carbon materials obtained from low and high temperature carbonization processes showed different characteristics. High purity and crystallinity of carbon materials were obtained from RHs carbonized at 2500°C. Furthermore, from Raman results, RHs carbonized at 2500°C exhibited low D/G ratio. This further reveals that the RHs carbonized at 2500°C possess minimal defects. The unique characteristics of RHs carbonized at high temperature indicate that they could be a promising material to be utilized in particular or various applications.

  17. Rare earth chalcogenides for use as high temperature thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Michiels, Jhn [Iowa State Univ., Ames, IA (United States)

    1996-01-02

    In the first part of the thesis, the electric resistivity, Seebeck coefficient, and Hall effect were measured in Xy(Y2S3)1-y (X = Cu, B, or Al), for y = 0.05 (Cu, B) or 0.025-0.075 for Al, in order to determine their potential as high- temperature (HT)(300-1000 C) thermoelectrics. Results indicate that Cu, B, Al- doped Y2S3 are not useful as HT thermoelectrics. In the second part, phase stability of γ-cubic LaSe1.47-1.48 and NdSe1.47 was measured periodically during annealing at 800 or 1000 C for the same purpose. In the Nd selenide, β phase increased with time, while the Nd selenide showed no sign of this second phase. It is concluded that the La selenide is not promising for use as HT thermoelectric due to the γ-to-β transformation, whereas the Nd selenide is promising.

  18. Space Electronics Operating at High Temperatures and Radiation Levels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective is to produce high efficiency DC/DC power modules in a small low profile package that can tolerate extreme environment conditions. The primary effort...

  19. High Temperature Superconducting Films and Multilayers for Electronics

    Science.gov (United States)

    1994-04-19

    High-Tc Superconductors," 1yal hio Discussion Leader at the Gordon Research Conference on Superconductivity, Oxnard, January 1994. 36...34 IEEE Trans. AppI. Supeirmd., vol. 3, 2295 (1993). 25. Harry Kroger and Uttam Ghoshal , "Can Superconductive digital Systems Compete with Semiconductor

  20. Solid lubricant materials for high temperatures: A review

    Science.gov (United States)

    Sliney, Harold E.

    1985-01-01

    Solid lubricants that can be used above 300 C in air are discussed, including coatings and self-lubricating composite bearing materials. The lubricants considered are representative dichalcogenides, graphite, graphite fluoride, polyimides, soft oxides, oxidatively stable fluorides, and hard coating materials. A few general design considerations revelant to solid lubrication are interspersed.

  1. Development of High-frequency Soft Magnetic Materials for Power Electronics

    Directory of Open Access Journals (Sweden)

    LIU Jun-chang

    2017-05-01

    Full Text Available The new requirements of high-frequency magnetic properties are put forward for electronic components with the rapid development of power electronics industry and the use of new electromagnetic materials. The properties of magnetic core, which is the key unit of electronic components, determine the performance of electronic components directly. Therefore, it's necessary to study the high-frequency soft magnetic materials. In this paper, the development history of four types of soft magnetic materials was reviewed. The advantages and disadvantages of each kind of soft magnetic materials and future development trends were pointed out. The emphases were placed on the popular soft magnetic composite materials in recent years. The tendency is to develop high-frequency soft magnetic composite materials with the particle size controllable, uniform coating layer on the core and a mass production method from laboratory to industrialization.

  2. High Temperature Thermoelectric Materials for Waste Heat Regeneration

    Science.gov (United States)

    2013-01-01

    Seebeck effect (17, 18). ............................................................................................7 Figure 7. Carrier concentration...5) where is Planck’s constant and is the density of states effective mass. The Seebeck coefficient is proportional to temperature... effect (17, 18). 2.2 The Electrical Conductivity The flow of current associated with the Seebeck voltage logically creates the search for TE

  3. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

    Directory of Open Access Journals (Sweden)

    Borislav Bogdanović

    2009-01-01

    Full Text Available For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

  4. Nanostructured Composite Materials for High Temperature Thermoelectric Energy Conversion

    Science.gov (United States)

    2012-08-29

    classes of materials, half-Heusler intermetallic bulk nanocomposites and bismuth -telluride based nanocomposites; • Complete structural and...measurements K. Stokes Physics/AMRI Bismuth telluride/metallic nanoparticle composites, transport measurements J. Wiley Chemistry/AMRI Chemical...as inclusions for nanocomposites. Here, the nanoparticles are synthesized by sol-gel chemistry using hafnium(IV) tert-butoxide and ammonium hydroxide

  5. Combustion and Plasma Synthesis of High Temperature Materials

    Science.gov (United States)

    1989-10-01

    cc 0v Table 4. Characteristics of Some Refractory Materials Dolomite and Magnesite-Based Characteristics Dolomite - Magnesite- Based Based...Other routes also exist such as calcination of organo-metallic compounds with a nitriding agent. Recently, thermal plasma processes have been used for

  6. Amorphous and Nanocrystalline High Temperature Magnetic Material for PWR

    Science.gov (United States)

    2006-03-01

    in collaboration with Magnetics, Inc. has produced nanopowders of the HITPERM materials. The work was extended to include study of...the interfacial stresses between the substrate and coating that arises during the coating processes. Alumina , Beryllia, Forsterite and Pt were...trial was performed to evaluate the efficacy of plasma synthesized ferrite coatings. NiZn ferrites were sprayed onto Alumina substrates using the

  7. High-temperature sensitivity and its acclimation for photosynthetic electron reactions of desert succulents

    Energy Technology Data Exchange (ETDEWEB)

    Chetti, M.B.; Nobel, P.S. (Univ. of California, Los Angeles (USA))

    1987-08-01

    Photosynthetic electron reactions of succulent plants from hot deserts are able to tolerate extremely high temperatures and to acclimate to seasonal increase in temperature. In this study, we report the influence of relatively long, in vivo, high-temperature treatments on electron transport reactions for two desert succulents, Agave deserti and Opuntia ficus-indica, species which can tolerate 60{degree}C. Whole chain electron transport averaged 3{degree}C more sensitive to a 1-hour high-temperature treatment than did PSII (Photosystem II) which in turn averaged 3{degree}C more sensitive than did PSI. For plants maintained at day/night air temperatures of 30{degree}C/20{degree}C, treatment at 50{degree}C cause these reactions to be inhibited an average of 39% during the first hour, an additional 31% during the next 4 hours, and 100% by 12 hours. Upon shifting the plants from 30{degree}C/20{degree}C to 45{degree}C/35{degree}C, the high temperatures where activity was inhibited 50% increased 3{degree}C to 8{degree}C for the three electron transport reactions, the half-times for acclimation averaging 5 days for A. deserti and 4 days for O. ficus-indica. For the 45{degree}C/35{degree}C plants treated at 60{degree}C for 1 hour, PSI activity was reduced by 54% for A. deserti and 36% for O. ficus-indica. Acclimation leads to a toleration of very high temperatures without substantial disruption of electron transport for these desert succulents, facilitating their survival in hot deserts. Indeed, the electron transport reactions of these species tolerate longer periods at higher temperatures than any other vascular plants so far reported.

  8. Materials for High-Temperature Hydrogen Fluorine Environments.

    Science.gov (United States)

    1981-03-04

    was detected). This complete phase diagram is being determined,(i) and the solid solution region extends to 57 mol % LaF3 in SrF2 with maximum melting...lanthanum chromite (LaCrQ 3 ), yttrium (Y), yttrium oxide (Y2 03 ), nickel aluminide (NiAl), Y20 3 doped Ni, magnesium oxide (MgO), aluminum oxide...with externally wound cooling coils. Figure 1 is an as-built flow diagram of the material test facility as designed by the Y’-12 Engineering Division

  9. Advances in electronic materials

    CERN Document Server

    Kasper, Erich; Grimmeiss, Hermann G

    2008-01-01

    This special-topic volume, Advances in Electronic Materials, covers various fields of materials research such as silicon, silicon-germanium hetero-structures, high-k materials, III-V semiconductor alloys and organic materials, as well as nano-structures for spintronics and photovoltaics. It begins with a brief summary of the formative years of microelectronics; now the keystone of information technology. The latter remains one of the most important global technologies, and is an extremely complex subject-area. Although electronic materials are primarily associated with computers, the internet

  10. The Application of High Temperature Superconducting Materials to Power Switches

    CERN Document Server

    March, S A; Ballarino, A

    2009-01-01

    Superconducting switches may find application in superconducting magnet systems that require energy extraction. Such superconducting switches could be bypass-switches that are operated in conjunction with a parallel resistor or dump-switches where all of the energy is dissipated in the switch itself. Bypass-switches are more suited to higher energy circuits as a portion of the energy can be dissipated in the external dump resistor. Dump- switches require less material and triggering energy as a lower switch resistance is needed to achieve the required total dump resistance. Both superconducting bypass-switches and superconducting dump-switches can be ther- mally activated. Switching times that are comparable to those obtained with mechanical bypass-switch systems can be achieved using a co-wound heater that is powered by a ca- pacitor discharge. Switches that have fast thermal diffusion times through the insulation can be modelled as a lumped system whereas those with slow thermal diffusion times were modelle...

  11. High-Temperature Air-Cooled Power Electronics Thermal Design: Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Waye, Scot [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-01

    Power electronics that use high-temperature devices pose a challenge for thermal management. With the devices running at higher temperatures and having a smaller footprint, the heat fluxes increase from previous power electronic designs. This project overview presents an approach to examine and design thermal management strategies through cooling technologies to keep devices within temperature limits, dissipate the heat generated by the devices and protect electrical interconnects and other components for inverter, converter, and charger applications. This analysis, validation, and demonstration intends to take a multi-scale approach over the device, module, and system levels to reduce size, weight, and cost.

  12. Validity of Eucken formula and Stokes’ viscosity relation in high-temperature electronically excited gases

    Energy Technology Data Exchange (ETDEWEB)

    Istomin, V. A.; Kustova, E. V.; Mekhonoshina, M. A. [Department of Mathematics and Mechanics, Saint Petersburg State University, 198504 Universitetskiy pr., 28, Saint Petersburg (Russian Federation)

    2014-12-09

    In the present work we evaluate the accuracy of the Eucken formula and Stokes’ viscosity relation in high temperature non-equilibrium air species with electronic excitation. The thermal conductivity coefficient calculated using the exact kinetic theory methods is compared with that obtained applying approximate formulas in the temperature range 200–20000 K. A modification of the Eucken formula providing a good agreement with exact calculations is proposed. It is shown that the Stokes viscosity relation is not valid in electronically excited monoatomic gases at temperatures higher than 2000 K.

  13. Materials and characterization techniques for high-temperature polymer electrolyte membrane fuel cells

    Directory of Open Access Journals (Sweden)

    Roswitha Zeis

    2015-01-01

    Full Text Available The performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC is critically dependent on the selection of materials and optimization of individual components. A conventional high-temperature membrane electrode assembly (HT-MEA primarily consists of a polybenzimidazole (PBI-type membrane containing phosphoric acid and two gas diffusion electrodes (GDE, the anode and the cathode, attached to the two surfaces of the membrane. This review article provides a survey on the materials implemented in state-of-the-art HT-MEAs. These materials must meet extremely demanding requirements because of the severe operating conditions of HT-PEMFCs. They need to be electrochemically and thermally stable in highly acidic environment. The polymer membranes should exhibit high proton conductivity in low-hydration and even anhydrous states. Of special concern for phosphoric-acid-doped PBI-type membranes is the acid loss and management during operation. The slow oxygen reduction reaction in HT-PEMFCs remains a challenge. Phosphoric acid tends to adsorb onto the surface of the platinum catalyst and therefore hampers the reaction kinetics. Additionally, the binder material plays a key role in regulating the hydrophobicity and hydrophilicity of the catalyst layer. Subsequently, the binder controls the electrode–membrane interface that establishes the triple phase boundary between proton conductive electrolyte, electron conductive catalyst, and reactant gases. Moreover, the elevated operating temperatures promote carbon corrosion and therefore degrade the integrity of the catalyst support. These are only some examples how materials properties affect the stability and performance of HT-PEMFCs. For this reason, materials characterization techniques for HT-PEMFCs, either in situ or ex situ, are highly beneficial. Significant progress has recently been made in this field, which enables us to gain a better understanding of underlying processes

  14. Materials and characterization techniques for high-temperature polymer electrolyte membrane fuel cells.

    Science.gov (United States)

    Zeis, Roswitha

    2015-01-01

    The performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) is critically dependent on the selection of materials and optimization of individual components. A conventional high-temperature membrane electrode assembly (HT-MEA) primarily consists of a polybenzimidazole (PBI)-type membrane containing phosphoric acid and two gas diffusion electrodes (GDE), the anode and the cathode, attached to the two surfaces of the membrane. This review article provides a survey on the materials implemented in state-of-the-art HT-MEAs. These materials must meet extremely demanding requirements because of the severe operating conditions of HT-PEMFCs. They need to be electrochemically and thermally stable in highly acidic environment. The polymer membranes should exhibit high proton conductivity in low-hydration and even anhydrous states. Of special concern for phosphoric-acid-doped PBI-type membranes is the acid loss and management during operation. The slow oxygen reduction reaction in HT-PEMFCs remains a challenge. Phosphoric acid tends to adsorb onto the surface of the platinum catalyst and therefore hampers the reaction kinetics. Additionally, the binder material plays a key role in regulating the hydrophobicity and hydrophilicity of the catalyst layer. Subsequently, the binder controls the electrode-membrane interface that establishes the triple phase boundary between proton conductive electrolyte, electron conductive catalyst, and reactant gases. Moreover, the elevated operating temperatures promote carbon corrosion and therefore degrade the integrity of the catalyst support. These are only some examples how materials properties affect the stability and performance of HT-PEMFCs. For this reason, materials characterization techniques for HT-PEMFCs, either in situ or ex situ, are highly beneficial. Significant progress has recently been made in this field, which enables us to gain a better understanding of underlying processes occurring during fuel cell

  15. High temperature properties of dispersion strengthened Al-Al4C3 materials

    Energy Technology Data Exchange (ETDEWEB)

    Besterci, M.; Slesar, M.; Miskovicova, M.; Pelikan, K.

    1987-01-01

    One of the most important properties of dispersion strengthened materials is their strength stability at high temperatures. The strength and plasticity of the material Al + 5 vol. pct Al4C3, tested in the temperature range from 100 to 400 C, are analyzed. On the basis of the experiments the functions for the temperature dependence of the strength and plasticity are described, the deformation process is evaluated, and the fracture mechanisms are quantified. 17 references.

  16. Measurements of Electrical and Electron Emission Properties of Highly Insulating Materials

    Science.gov (United States)

    Dennison, J. R.; Brunson, Jerilyn; Hoffman, Ryan; Abbott, Jonathon; Thomson, Clint; Sim, Alec

    2005-01-01

    Highly insulating materials often acquire significant charges when subjected to fluxes of electrons, ions, or photons. This charge can significantly modify the materials properties of the materials and have profound effects on the functionality of the materials in a variety of applications. These include charging of spacecraft materials due to interactions with the severe space environment, enhanced contamination due to charging in Lunar of Martian environments, high power arching of cables and sources, modification of tethers and ion thrusters for propulsion, and scanning electron microscopy, to name but a few examples. This paper describes new techniques and measurements of the electron emission properties and resistivity of highly insulating materials. Electron yields are a measure of the number of electrons emitted from a material per incident particle (electron, ion or photon). Electron yields depend on incident species, energy and angle, and on the material. They determine the net charge acquired by a material subject to a give incident flu. New pulsed-beam techniques will be described that allow accurate measurement of the yields for uncharged insulators and measurements of how the yields are modified as charge builds up in the insulator. A key parameter in modeling charge dissipation is the resistivity of insulating materials. This determines how charge will accumulate and redistribute across an insulator, as well as the time scale for charge transport and dissipation. Comparison of new long term constant-voltage methods and charge storage methods for measuring resistivity of highly insulating materials will be compared to more commonly used, but less accurate methods.

  17. Infrared Radiometry of High-Temperature Processes During the Spot Heating of Materials

    Science.gov (United States)

    Afanas'yev, A. V.; Orlov, I. Ya.; Khrulev, A. E.

    2004-08-01

    We propose the method of a ``shifted'' meter for monitoring the temperature regimes during the spot heating of materials and present the results of an experimental study of the proposed method in the case of the electron-beam welding of zirconium pipes in vacuum.

  18. Biodeuterated Materials: High-Temperature Lubricants from Algae.

    Science.gov (United States)

    1986-01-06

    methanol for lipid extrac- tion and esterification of the fatty acids did not appear to be a likely source of hydrogen substitution on the deuterocarbon...marked as Spoehr and Milner obtained in H20 media [25]. The unusually high concentration of oleic acid (18:1) obtained with Chlorella growing on an agar... esterification with a fatty acid with the same or a different number of car- bon atoms: CD 3 - (CD 2 )16 - C_ 0 LiAID4 CD3 - (CD 2)16 - CD2 - OD OGD 0 +CD3

  19. High Temperature Materials Laboratory User Program: 19th Annual Report, October 1, 2005 - September 30, 2006

    Energy Technology Data Exchange (ETDEWEB)

    Pasto, Arvid [ORNL

    2007-08-01

    Annual Report contains overview of the High Temperature Materials Laboratory User Program and includes selected highlights of user activities for FY2006. Report is submitted to individuals within sponsoring DOE agency and to other interested individuals.

  20. Electron Beam Materials Processing

    Science.gov (United States)

    Powers, Donald E.

    2012-06-01

    In electron beam processing, a well-defined beam of relatively energetic electrons produced by a high voltage acceleration gap is used to transmit thermal energy into a material in a precise manner. This controlled deposition of heat is employed in a wide variety of industrial applications for precision cutting, drilling, and welding of materials as well as annealing, glazing, and surface hardening. This chapter will describe the equipment used and the most prominent industrial applications for this process.

  1. Scalable Sub-micron Patterning of Organic Materials Toward High Density Soft Electronics.

    Science.gov (United States)

    Kim, Jaekyun; Kim, Myung-Gil; Kim, Jaehyun; Jo, Sangho; Kang, Jingu; Jo, Jeong-Wan; Lee, Woobin; Hwang, Chahwan; Moon, Juhyuk; Yang, Lin; Kim, Yun-Hi; Noh, Yong-Young; Jaung, Jae Yun; Kim, Yong-Hoon; Park, Sung Kyu

    2015-09-28

    The success of silicon based high density integrated circuits ignited explosive expansion of microelectronics. Although the inorganic semiconductors have shown superior carrier mobilities for conventional high speed switching devices, the emergence of unconventional applications, such as flexible electronics, highly sensitive photosensors, large area sensor array, and tailored optoelectronics, brought intensive research on next generation electronic materials. The rationally designed multifunctional soft electronic materials, organic and carbon-based semiconductors, are demonstrated with low-cost solution process, exceptional mechanical stability, and on-demand optoelectronic properties. Unfortunately, the industrial implementation of the soft electronic materials has been hindered due to lack of scalable fine-patterning methods. In this report, we demonstrated facile general route for high throughput sub-micron patterning of soft materials, using spatially selective deep-ultraviolet irradiation. For organic and carbon-based materials, the highly energetic photons (e.g. deep-ultraviolet rays) enable direct photo-conversion from conducting/semiconducting to insulating state through molecular dissociation and disordering with spatial resolution down to a sub-μm-scale. The successful demonstration of organic semiconductor circuitry promise our result proliferate industrial adoption of soft materials for next generation electronics.

  2. High temperature indentation behavior of eutectic lead-free solder materials

    Directory of Open Access Journals (Sweden)

    Worrack H.

    2010-06-01

    Full Text Available Electronic malfunction caused by thermal stresses is one major problem in modern electronic industries. Therefore, the precise knowledge of the mechanical solder material properties as a function of temperature is required. Nanoindentation and its potential of recording load-displacement curves is a widely-used miniature test for the determination of Young’s modulus and hardness values. Furthermore, such tests can be performed in a temperature range from Room Temperature (RT up to +500°C by using a Hot-Stage add on. In this paper the lead-free solder alloys Sn91Zn9 and Sn42Bi58, and also copper and fused silica, which is used for the indenter calibration are investigated. The results for quartz and copper agree with the published values in several references. However, the Young’s modulus of Sn42Bi58 as a function of temperature differs from the values presented in the literature. Due to delayed material response in the unloading regime it must be assumed that creep effects lead to an incorrect automatic data evaluation. Investigation and understanding of the creep behavior is part of this paper. For this purpose a visco-elastic material model is used to model the indentation response at elevated temperatures and to determine the corresponding viscous material constants.

  3. Processing Techniques Developed to Fabricate Lanthanum Titanate Piezoceramic Material for High-Temperature Smart Structures

    Science.gov (United States)

    Goldsby, Jon C.; Farmer, Serene C.; Sayir, Ali

    2004-01-01

    Piezoelectric ceramic materials are potential candidates for use as actuators and sensors in intelligent gas turbine engines. For piezoceramics to be applied in gas turbine engines, they will have to be able to function in temperatures ranging from 1000 to 2500 F. However, the maximum use temperature for state-of-the-art piezoceramic materials is on the order of 300 to 400 F. Research activities have been initiated to develop high-temperature piezoceramic materials for gas turbine engine applications. Lanthanum titanate has been shown to have high-temperature piezoelectric properties with Curie temperatures of T(sub c) = 1500 C and use temperatures greater than 1000 C. However, the fabrication of lanthanum titanate poses serious challenges because of the very high sintering temperatures required for densification. Two different techniques have been developed at the NASA Glenn Research Center to fabricate dense lanthanum titanate piezoceramic material. In one approach, lower sintering temperatures were achieved by adding yttrium oxide to commercially available lanthanum titanate powder. Addition of only 0.1 mol% yttrium oxide lowered the sintering temperature by as much as 300 C, to just 1100 C, and dense lanthanum titanate was produced by pressure-assisted sintering. The second approach utilized the same commercially available powders but used an innovative sintering approach called differential sintering, which did not require any additive.

  4. Electron Beam Materials Irradiators

    Science.gov (United States)

    Cleland, Marshall R.

    2012-06-01

    Radiation processing is a well established method for enhancing the properties of materials and commercial products by treating them with ionizing energy in the form of high-energy electrons, X-rays, and gamma rays. Beneficial effects include polymerizing, cross-linking, grafting and degrading plastics, sterilizing single-use medical devices, disinfecting and disinfesting fresh foods, purifying drinking water, treating wastewater and other toxic waste materials that harm the environment, and many other applications that are still being evaluated. Industrial electron accelerators of several types have been developed and are being used for these applications. More than 1800 electron accelerators are presently installed in facilities worldwide for these purposes.

  5. Summary of U. S. LMFBR programs on high temperature structural design and associated materials testing

    Energy Technology Data Exchange (ETDEWEB)

    1976-10-01

    This document was prepared at the request of the Division of Reactor Development and Demonstration (DRDD), U.S. Energy Research and Development Administration. Four general areas of research and development are included: high-temperature structural design; irradiation effects--mechanical properties of structural materials; sodium environmental effects--influence of sodium on mechanical properties; and general material qualification.

  6. Performance testing of elastomeric seal materials under low and high temperature conditions: Final report

    Energy Technology Data Exchange (ETDEWEB)

    BRONOWSKI,DAVID R.

    2000-06-01

    The US Department of Energy Offices of Defense Programs and Civilian Radioactive Waste Management jointly sponsored a program to evaluate elastomeric O-ring seal materials for radioactive material shipping containers. The report presents the results of low- and high-temperature tests conducted on 27 common elastomeric compounds.

  7. Measurement of the high-temperature strain of UHTC materials using chemical composition gratings

    Science.gov (United States)

    Xie, Weihua; Meng, Songhe; Jin, Hua; Du, Chong; Wang, Libin; Peng, Tao; Scarpa, F.; Huo, Shiyu

    2016-05-01

    This paper proposes a simple bonding and measuring technique to realise silica-based chemical composition gratings’ (CCGs) high temperature applications on hot structures. We describe a series of experiments on CCGs to measure the thermal and mechanical response characteristics of ultra-high temperature ceramic (UHTC) materials when the maximum temperature is above 1000 °C. Response characteristics are obtained at the heating and cooling stages. Results show that the wavelength response of the CCGs bonded on the UHTC plate increases non-linearly with increasing temperatures, but decreases almost linearly with decreasing temperatures. The temperature-dependent strain transfer coefficients are calculated theoretically and experimentally; results show that the values of strain transfer coefficients below 1000 °C are significantly affected by the thermal expansion coefficient of the substrate material and the interface. The strain transfer coefficient value tends to vary slowly between 0.616 and 0.626 above 700 °C.

  8. [Effect of high-temperature phase change material on the performance of infrared decoy].

    Science.gov (United States)

    Wu, Ting-Ting; Chen, Xin; Han, Ai-Jun; Ye, Ming-Quan; Zhao, Min-Chun

    2013-10-01

    The impact of the high-temperature phase change material on conventional infrared decoy's combustion performance and infrared radiation characteristics was studied. The selected high-temperature phase change materials did not reduce infrared radiation in the 3-5 microm or 8-14 microm band of infrared decoy, while extended the burning time, and reduced the burning rate of the grain, thus prolonged the effective interference time of IR decoy. The results show the phase change material is effective infrared decoy functional additives.

  9. Recent Progress in Nanostructured Oxide TE Materials for Power Generation at High Temperatures

    DEFF Research Database (Denmark)

    Van Nong, Ngo; Pryds, Nini; Linderoth, Søren

    Thermoelectric (TE) materials, which can convert waste heat into electricity, could play an important role in a global sustainable energy solution and environmental problems. Metal oxides have been considered as potential TE materials for power generation that can operate at high temperatures......σT/κ , where S, σ, T and κ are the Seebeck coefficient, electrical conductivity, absolute temperature and thermal conductivity, respectively). We have fabricated high-quality oxide TE materials based on Ca3Co4O9 by optimizing the method for synthesis, modifying the compositions...... and by nanostructuring. This report will focus on the high temperature TE properties of heavy ions doping nanostrcutred Ca3Co4O9 oxides, which exhibit promising ZT, implying suitable polycrystalline oxide TE materials for power generation from waste heat....

  10. A harsh environment wireless pressure sensing solution utilizing high temperature electronics.

    Science.gov (United States)

    Yang, Jie

    2013-02-27

    Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines.

  11. A Harsh Environment Wireless Pressure Sensing Solution Utilizing High Temperature Electronics

    Science.gov (United States)

    Yang, Jie

    2013-01-01

    Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines. PMID:23447006

  12. Localized Electron Trap Modification as a Result of Space Weather Exposure in Highly Disordered Insulating Materials

    Science.gov (United States)

    2017-03-06

    Chemistry that Drives Them) Due to Exposure to High Energy GEO-like Electrons Conference Proceeding Advanced Maui Optical and Space Surveillance...distribution is unlimited. 28 References 1. Awaja, F., et al., Surface molecular degradation of selected high performance polymer composites under low...6 2.3. Material Chemistry

  13. High-Temperature Structures, Adhesives, and Advanced Thermal Protection Materials for Next-Generation Aeroshell Design

    Science.gov (United States)

    Collins, Timothy J.; Congdon, William M.; Smeltzer, Stanley S.; Whitley, Karen S.

    2005-01-01

    The next generation of planetary exploration vehicles will rely heavily on robust aero-assist technologies, especially those that include aerocapture. This paper provides an overview of an ongoing development program, led by NASA Langley Research Center (LaRC) and aimed at introducing high-temperature structures, adhesives, and advanced thermal protection system (TPS) materials into the aeroshell design process. The purpose of this work is to demonstrate TPS materials that can withstand the higher heating rates of NASA's next generation planetary missions, and to validate high-temperature structures and adhesives that can reduce required TPS thickness and total aeroshell mass, thus allowing for larger science payloads. The effort described consists of parallel work in several advanced aeroshell technology areas. The areas of work include high-temperature adhesives, high-temperature composite materials, advanced ablator (TPS) materials, sub-scale demonstration test articles, and aeroshell modeling and analysis. The status of screening test results for a broad selection of available higher-temperature adhesives is presented. It appears that at least one (and perhaps a few) adhesives have working temperatures ranging from 315-400 C (600-750 F), and are suitable for TPS-to-structure bondline temperatures that are significantly above the traditional allowable of 250 C (482 F). The status of mechanical testing of advanced high-temperature composite materials is also summarized. To date, these tests indicate the potential for good material performance at temperatures of at least 600 F. Application of these materials and adhesives to aeroshell systems that incorporate advanced TPS materials may reduce aeroshell TPS mass by 15% - 30%. A brief outline is given of work scheduled for completion in 2006 that will include fabrication and testing of large panels and subscale aeroshell test articles at the Solar-Tower Test Facility located at Kirtland AFB and operated by Sandia

  14. Summary of workshop on high temperature materials based on Laves phases

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    The Offices of Fossil Energy and Basic Energy Sciences of the Department of Energy jointly sponsored the Workshop on High Temperature Materials Based on Laves Phases in conjunction with the Tenth Annual Conference on Fossil Energy Materials held at the Radisson Summit Hill Hotel in Knoxville, Tennessee on May 14-16, 1996. The objective of this workshop was to review the current status and to address critical issues in the development of new-generation high-temperature structural materials based on Laves phases. The one-day workshop included two sessions of overview presentations and a session of discussion on critical scientific and technological issues. The Laves phases represent an abundant class of intermetallic alloys with possible high-temperature structural applications. Laves phases form at or near the AB{sub 2} composition, and there are over 360 binary Laves phases. The ability of these alloys to dissolve considerable amounts of ternary alloying additions provides over 900 combined binary and ternary Laves phases. Many Laves phases have unique properties which make them attractive for high-temperature structural use. At half their homologous temperature, they retain >0.85 of their ambient yield strength, which is higher than all other intermetallics. Many of the Laves phases also have high melting temperatures, excellent creep properties, reasonably low densities, and for alloys containing Cr, Al, Si or Be, good oxidation resistance. Despite these useful properties, the tendency for low-temperature brittleness has limited the potential application of this large class of alloys.

  15. A Review on Die Attach Materials for SiC-Based High-Temperature Power Devices

    Science.gov (United States)

    Chin, Hui Shun; Cheong, Kuan Yew; Ismail, Ahmad Badri

    2010-08-01

    Recently, high-temperature power devices have become a popular discussion topic because of their various potential applications in the automotive, down-hole oil and gas industries for well logging, aircraft, space exploration, nuclear environments, and radars. Devices for these applications are fabricated on silicon carbide-based semiconductor material. For these devices to perform effectively, an appropriate die attach material with specific requirements must be selected and employed correctly. This article presents a review of this topic, with a focus on the die attach materials operating at temperatures higher than 623 K (350 °C). Future challenges and prospects related to high-temperature die attach materials also are proposed at the end of this article.

  16. Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, James; Gewirth, Andrew; Sehitoglu, Huseyin; Sofronis, Petros; Robertson, Ian

    2014-01-16

    The objective of this project is to develop a fundamental understanding of the mechanisms that limit materials durability for very high-temperature applications. Current design limitations are based on material strength and corrosion resistance. This project will characterize the interactions of high-temperature creep, fatigue, and environmental attack in structural metallic alloys of interest for the very high-temperature gas-cooled reactor (VHTR) or Next–Generation Nuclear Plant (NGNP) and for the associated thermo-chemical processing systems for hydrogen generation. Each of these degradation processes presents a major materials design challenge on its own, but in combination, they can act synergistically to rapidly degrade materials and limit component lives. This research and development effort will provide experimental results to characterize creep-fatigue-environment interactions and develop predictive models to define operation limits for high-temperature structural material applications. Researchers will study individually and in combination creep-fatigue-environmental attack processes in Alloys 617, 230, and 800H, as well as in an advanced Ni-Cr oxide dispersion strengthened steel (ODS) system. For comparison, the study will also examine basic degradation processes in nichrome (Ni-20Cr), which is a basis for most high-temperature structural materials, as well as many of the superalloys. These materials are selected to represent primary candidate alloys, one advanced developmental alloy that may have superior high-temperature durability, and one model system on which basic performance and modeling efforts can be based. The research program is presented in four parts, which all complement each other. The first three are primarily experimental in nature, and the last will tie the work together in a coordinated modeling effort. The sections are (1) dynamic creep-fatigue-environment process, (2) subcritical crack processes, (3) dynamic corrosion – crack

  17. Trap Characterization in High Field, High Temperature Stressed Gallium Nitride High Electron Mobility Transistors

    Science.gov (United States)

    2013-03-01

    to a one dimensional Poisson - Schrodinger model with the same parameters of the fabricated device. The largest dispersion occurred before threshold...of self -heating to further improve reliability. The use of sapphire and diamond as a substrate to improve thermal characteristics was investigated...This is consistent with prior work [14]. Devices tested at higher temperatures had higher drain currents. This was to be expected due to additional

  18. Electronic origin of high-temperature superconductivity in single-layer FeSe superconductor.

    Science.gov (United States)

    Liu, Defa; Zhang, Wenhao; Mou, Daixiang; He, Junfeng; Ou, Yun-Bo; Wang, Qing-Yan; Li, Zhi; Wang, Lili; Zhao, Lin; He, Shaolong; Peng, Yingying; Liu, Xu; Chen, Chaoyu; Yu, Li; Liu, Guodong; Dong, Xiaoli; Zhang, Jun; Chen, Chuangtian; Xu, Zuyan; Hu, Jiangping; Chen, Xi; Ma, Xucun; Xue, Qikun; Zhou, X J

    2012-07-03

    The recent discovery of high-temperature superconductivity in iron-based compounds has attracted much attention. How to further increase the superconducting transition temperature (T(c)) and how to understand the superconductivity mechanism are two prominent issues facing the current study of iron-based superconductors. The latest report of high-T(c) superconductivity in a single-layer FeSe is therefore both surprising and significant. Here we present investigations of the electronic structure and superconducting gap of the single-layer FeSe superconductor. Its Fermi surface is distinct from other iron-based superconductors, consisting only of electron-like pockets near the zone corner without indication of any Fermi surface around the zone centre. Nearly isotropic superconducting gap is observed in this strictly two-dimensional system. The temperature dependence of the superconducting gap gives a transition temperature T(c)~ 55 K. These results have established a clear case that such a simple electronic structure is compatible with high-T(c) superconductivity in iron-based superconductors.

  19. Effects of High Energy Electron Irradiation on a Yttrium Barium(2) Copper(3) Oxygen(7-delta) High Temperature Superconductor

    Science.gov (United States)

    1991-09-01

    expulsion of magnetic fields from the interior of a superconductor such that B = 0 and is the phenome- non that explains magnetic levitation . From Ohm’s Law...2Cu 30 7 - HIGH TEMPERATURE SUPERCONDUCTOR by Sean Mark Connors September 1991 Thesis Advisor: X. K. Maruyama Approved for public release...if necessary and identify by btock numbe,) FiE GP<P ,€ 5 pCOO HIGH TEMPERATURE SUPERCONDUCTORS , IRRADIATION EFFECTS, ELECTRON IRRADIATION

  20. High time resolution reconstruction of electron temperature profiles with a neural network in C-2U

    Science.gov (United States)

    Player, Gabriel; Magee, Richard; Trask, Erik; Korepanov, Sergey; Clary, Ryan; Tri Alpha Energy Team

    2017-10-01

    One of the most important parameters governing fast ion dynamics in a plasma is the electron temperature, as the fast ion-electron collision rate goes as νei Te3 / 2 . Unfortunately, the electron temperature is difficult to directly measure-methods relying on high-powered laser pulses or fragile probes lead to limited time resolution or measurements restricted to the edge. In order to rectify the lack of time resolution on the Thomson scattering data in the core, a type of learning algorithm, specifically a neural network, was implemented. This network uses 3 hidden layers to correlate information from nearly 250 signals, including magnetics, interferometers, and several arrays of bolometers, with Thomson scattering data over the entire C-2U database, totalling nearly 20,000 samples. The network uses the Levenberg-Marquardt algorithm with Bayesian regularization to learn from the large number of samples and inputs how to accurately reconstruct the entire electron temperature time history at a resolution of 500 kHz, a huge improvement over the 2 time points per shot provided by Thomson scattering. These results can be used in many different types of analysis and plasma characterization-in this work, we use the network to quantify electron heating.

  1. GaN-Based High Temperature and Radiation-Hard Electronics for Harsh Environments

    Science.gov (United States)

    Son, Kyung-ah; Liao, Anna; Lung, Gerald; Gallegos, Manuel; Hatakeh, Toshiro; Harris, Richard D.; Scheick, Leif Z.; Smythe, William D.

    2010-01-01

    We develop novel GaN-based high temperature and radiation-hard electronics to realize data acquisition electronics and transmitters suitable for operations in harsh planetary environments. In this paper, we discuss our research on metal-oxide-semiconductor (MOS) transistors that are targeted for 500 (sup o)C operation and >2 Mrad radiation hardness. For the target device performance, we develop Schottky-free AlGaN/GaN MOS transistors, where a gate electrode is processed in a MOS layout using an Al2O3 gate dielectric layer....

  2. The influence of high temperatures on the tribological properties of automotive friction materials

    Science.gov (United States)

    Savage, Luke

    Temperatures of over 800C can be generated at the frictional interface within the brake systems of large vehicles, such high temperatures result in severe wear at the frictional interface, and can also lead to a very dangerous condition known as brake fade, characterised by a sharp fall in the coefficient of friction between the pad and disc, resulting in a catastrophic loss of braking efficiency. Common friction materials are very specialised composites often containing up to 15 components bound together within a phenolic resin matrix. The high temperature behaviour of the various constituents of friction materials were investigated using thermogravimetric analysis, focusing in particular on the thermal decomposition of the phenolic resin matrix material, where it has been firmly established that the thermal decomposition products of phenolic resin are the primary cause of brake fade. This has lead to the development of a novel approach for reducing fade in conventional resin based friction materials, involving a partial carbonisation to 400C. The high temperature wear characteristics of both modified and conventional friction materials were examined using standard dynamometer tests, as well as a 'continuous drag' type test machine, equipped with a heating facility. During this study a number of factors were identified as the main influences on the overall wear behaviour of friction materials. These included test temperature, sample test history, and the various effects of friction films, which were the subject of a detailed analysis. The formation of friction films was found to be an important facet of a successful friction material, producing a reduction in wear at the frictional interface. Films were examined and analysed using EDX, SEM, and X-ray diffraction techniques, which revealed the presence of a high proportion of magnetite (Fe3O4), containing iron which originated from the disc surface. It was established that the incorporation of iron in friction

  3. High-energy electron-induced damage production at room temperature in aluminum-doped silicon

    Science.gov (United States)

    Corbett, J. W.; Cheng, L. J.; Jaworowski, A.; Karins, J. P.; Lee, Y. H.; Lindstroem, L.; Mooney, P. M.; Oehrlen, G.; Wang, K. L.

    1979-01-01

    DLTS and EPR measurements are reported on aluminum-doped silicon that was irradiated at room temperature with high-energy electrons. Comparisons are made to comparable experiments on boron-doped silicon. Many of the same defects observed in boron-doped silicon are also observed in aluminum-doped silicon, but several others were not observed, including the aluminum interstitial and aluminum-associated defects. Damage production modeling, including the dependence on aluminum concentration, is presented.

  4. Encapsulation of High Temperature Phase Change Materials for Thermal Energy Storage

    Science.gov (United States)

    Nath, Rupa

    Thermal energy storage is a major contributor to bridge the gap between energy demand (consumption) and energy production (supply) by concentrating solar power. The utilization of high latent heat storage capability of phase change materials is one of the keys to an efficient way to store thermal energy. However, some of the limitations of the existing technology are the high volumetric expansion and low thermal conductivity of phase change materials (PCMs), low energy density, low operation temperatures and high cost. The present work deals with encapsulated PCM system, which operates at temperatures above 500°C and takes advantage of the heat transfer modes at such high temperatures to overcome the aforementioned limitations of PCMs. Encapsulation with sodium silicate coating on preformed PCM pellets were investigated. A low cost, high temperature metal, carbon steel has been used as a capsule for PCMs with a melting point above 500° C. Sodium silicate and high temperature paints were used for oxidation protection of steel at high temperatures. The emissivity of the coatings to enhance heat transfer was investigated.

  5. Continuous point-like high-temperature laser discharge produced by terahertz free electron laser

    Directory of Open Access Journals (Sweden)

    V. V. Kubarev

    2017-09-01

    Full Text Available A continuous point-like laser discharge of record high temperature has been produced in argon at atmospheric pressure with focusing of the radiation of the Novosibirsk terahertz free electron laser (NovoFEL. According to spectral measurements, the temperature in the center of the millimeter-sized plasma sphere was 28000 K at a plasma density of 1.5×1017 cm-3 and an average NovoFEL power of 200 W at a wavelength of 130 μm (2.3 THz.

  6. Heat treated 9 Cr-1 Mo steel material for high temperature application

    Energy Technology Data Exchange (ETDEWEB)

    Jablonski, Paul D.; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-08-21

    The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

  7. In situ measurements of high temperature growth of correlated systems: a materials by design scheme

    Science.gov (United States)

    He, Hua

    There is great interest in developing new ways to use predictive theory to accelerate materials synthesis. We have previously shown that DFT +DMFT electronic structure calculations are successful at predicting gaps and ordered moments, even when correlations are very strong.[ 1 , 2 ] Building on these results, we set out to explore an even closer integration of theory and synthesis, aiming to discover new routes for doping Mott insulators and producing new superconductors. In situ high temperature high energy X-ray diffraction is used to determine the crystal structures of compounds just as they form from the growths, and the structural information is used as input for DFT +DMFT calculations that predict functionality, closing the synthesis loop by suggesting productive new directions. Using this approach, we have investigated the transition metal oxysulfide system Ba-Co-S-O and successfully discovered the new compound BaCoSO, and identified it as an interesting small gap Mott insulator by DFT +DMFT calculations even before any traditional crystal growth is attempted in the lab We acknowledge the Office of Assistant Secretary of Defense for Research and Engineering for providing the NSSEFF funds that supported this research.

  8. Nanostructured oxide materials and modules for high temperature power generation from waste heat

    DEFF Research Database (Denmark)

    Van Nong, Ngo; Pryds, Nini

    2013-01-01

    are not easily satisfied by conventional thermoelectric materials. Not only they must possess a sufficient thermoelectric performance, they should also be stable at high temperatures, nontoxic and low-cost comprising elements, and must be also able to be processed and shaped cheaply. Oxides are among......A large amount of thermal energy that emitted from many industrial processes is available as waste heat. Thermoelectric power generators that convert heat directly into electricity can offer a very promising way for waste heat recovery. However, the requirements for this task place in the materials...... the strongest candidate materials for this purpose. In this review, the progress in the development of two representative p- and n-type novel oxide materials based on Ca3Co4O9 and doped-ZnO is presented. Thermoelectric modules built up from these oxides were fabricated, tested at high temperatures, and compared...

  9. THE INFLUENCE OF HIGH-TEMPERATURE BRAZING UPON INDICATORS OF MATERIAL BRAZEABILITY

    Directory of Open Access Journals (Sweden)

    Roman Koleňák

    2010-03-01

    Full Text Available The effect of both common and extreme parameters of AISI 321stainless steel high-temperature brazing using the NI 102 brazing alloy upon material brazeability indicators. The ascertainment of the wetting angle, the area over which Ni brazing alloy spreads, the width of AISI 321 steel's dissolubility band, and the width of Ni brazing alloy’s diffusion band into the basic material.

  10. Recent progress of high performance polymer OLED and OPV materials for organic printed electronics.

    Science.gov (United States)

    Sekine, Chizu; Tsubata, Yoshiaki; Yamada, Takeshi; Kitano, Makoto; Doi, Shuji

    2014-06-01

    The development of organic printed electronics has been expanding to a variety of applications and is expected to bring innovations to our future life. Along with this trend, high performance organic materials with cost-efficient fabrication processes and specific features such as thin, light weight, bendable, and low power consumption are required. A variety of organic materials have been investigated in the development of this field. The basic guidelines for material design and the recent progress of polymer-based organic light-emitting diodes (OLEDs) and organic photovoltaic cells (OPVs) are reported.

  11. High temperature thermal storage for solar gas turbines using encapsulated phase change materials

    CSIR Research Space (South Africa)

    Klein, P

    2014-01-01

    Full Text Available The development of high temperature thermal storage systems is required to increase the solar share of solar-hybrid gas turbine cycles. This paper proposes a pressurised packed bed of Encapsulated Phase Change Materials (EPCM) as a thermal storage...

  12. Ultra-Fast Boriding in High-Temperature Materials Processing Industries

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-12-01

    This factsheet describes a research project whose main objective is to further develop, optimize, scale-up, and commercialize an ultra-fast boriding (also referred to as “boronizing”) process that can provide much higher energy efficiency, productivity, and near-zero emissions in many of the high-temperature materials processing industries.

  13. A method for estimating the temperature in high energy density free electron laser experiments

    Energy Technology Data Exchange (ETDEWEB)

    Principi, Emiliano, E-mail: emiliano.principi@unicam.i [CNISM, Dipartimento di Fisica, Universita degli Studi di Camerino via Madonna delle Carceri, I-62032 Camerino (Italy); Ferrante, Carino; Filipponi, Adriano [Dipartimento di Fisica, Universita degli Studi dell' Aquila, Via Vetoio, I-67100 L' Aquila (Italy); Bencivenga, Filippo; D' Amico, Francesco; Masciovecchio, Claudio [Synchrotron ELETTRA, Strada Statale 14-I-34149 Basovizza, Trieste (Italy); Di Cicco, Andrea [CNISM, Dipartimento di Fisica, Universita degli Studi di Camerino via Madonna delle Carceri, I-62032 Camerino (Italy); IMPMC, Universite Paris 6, CNRS, 140 rue de Lourmel, 75015 Paris (France)

    2010-09-21

    Present and forthcoming free electron laser (FEL) large scale facilities deliver high fluence ultrafast soft and hard X-ray pulses able to create and probe warm dense matter (WDM). Proper diagnostic for basic physical quantities, like temperature and density, is necessary, but the short lifetime of the WDM state (few ps) makes their measurements a challenging task. In this work we propose a method to estimate the WDM temperature using the experimental information from a slow temperature pyrometric probe exploiting the properties of the heat diffusion equation. Numerical simulations show that for typical thin foil samples, a temperature measurement with 1-10{mu}s temporal resolution at the distance of about 300-500{mu}m from the beam center contains sufficient information to retrieve the initial spatial temperature distribution with sufficient accuracy providing information on the temperature reached in the WDM regime. The inversion of the experimental information is obtained by means of a Bayesian approach exploiting a Metropolis Monte Carlo numerical procedure. The model and calculations presented in this work provide the theoretical background for the development of a device for temperature diagnostics of the TIMEX end-station at the Fermi-Elettra FEL facility.

  14. Determining the tensile response of materials at high temperature using DIC and the Virtual Fields Method

    Science.gov (United States)

    Valeri, Guillermo; Koohbor, Behrad; Kidane, Addis; Sutton, Michael A.

    2017-04-01

    An experimental approach based on Digital Image Correlation (DIC) is successfully applied to predict the uniaxial stress-strain response of 304 stainless steel specimens subjected to nominally uniform temperatures ranging from room temperature to 900 °C. A portable induction heating device equipped with custom made water-cooled copper coils is used to heat the specimen. The induction heater is used in conjunction with a conventional tensile frame to enable high temperature tension experiments. A stereovision camera system equipped with appropriate band pass filters is employed to facilitate the study of full-field deformation response of the material at elevated temperatures. Using the temperature and load histories along with the full-field strain data, a Virtual Fields Method (VFM) based approach is implemented to identify constitutive parameters governing the plastic deformation of the material at high temperature conditions. Results from these experiments confirm that the proposed method can be used to measure the full field deformation of materials subjected to thermo-mechanical loading.

  15. Experimental measurements of thermal properties of high-temperature refractory materials used for thermal energy storage

    Science.gov (United States)

    El-Leathy, Abdelrahman; Jeter, Sheldon; Al-Ansary, Hany; Abdel-Khalik, Said; Golob, Matthew; Danish, Syed Noman; Saeed, Rageh; Djajadiwinata, Eldwin; Al-Suhaibani, Zeyad

    2016-05-01

    This paper builds on studies conducted on thermal energy storage (TES) systems that were built as a part of the work performed for a DOE-funded SunShot project titled "High Temperature Falling Particle Receiver". In previous studies, two small-scale TES systems were constructed for measuring heat loss at high temperatures that are compatible with the falling particle receiver concept, both of which had shown very limited heat loss. Through the course of those studies, it became evident that there was a lack of information about the thermal performance of some of the insulating refractory materials used in the experiments at high temperatures, especially insulating firebrick and perlite concrete. This work focuses on determining the thermal conductivities of those materials at high temperatures. The apparatus consists of a prototype cylindrical TES bin built with the same wall construction used in previous studies. An electric heater is placed along the centerline of the bin, and thermocouples are used to measure temperature at the interfaces between all layers. Heat loss is measured across one of the layers whose thermal conductivity had already been well established using laboratory experiments. This value is used to deduce the thermal conductivity of other layers. Three interior temperature levels were considered; namely, 300°C, 500°C, and 700°C. Results show that the thermal conductivity of insulating firebrick remains low (approximately 0.22 W/m.K) at an average layer temperature as high as 640°C, but it was evident that the addition of mortar had an impact on its effective thermal conductivity. Results also show that the thermal conductivity of perlite concrete is very low, approximately 0.15 W/m.K at an average layer temperature of 360°C. This is evident by the large temperature drop that occurs across the perlite concrete layer. These results should be useful for future studies, especially those that focus on numerical modeling of TES bins.

  16. High Temperature Materials Laboratory Thirteenth Annual Report: October 1999 Through September 2000

    Energy Technology Data Exchange (ETDEWEB)

    Pasto, AE

    2001-11-07

    The High Temperature Materials Laboratory (HTML) User Program continued to work with industrial, academic, and governmental users this year, accepting 86 new projects and developing 50 new user agreements. The table on the following page presents the breakdown of these statistics. The figure on page 2 depicts the continued growth in user agreements and user projects. You may note that our total number of proposals is nearing 1000, and we expect to achieve this number in our first proposal review meeting of FY 2001. The large number of new agreements bodes well for the future. A list of proposals to the HTML follows this section; at the end of the report, we present a list of agreements between HTML and universities and industries, broken down by state. Program highlights this year included several outstanding user projects (some of which are discussed in later sections), the annual meeting of the HTML Programs Senior Advisory Committee, the completion of a formal Multiyear Program Plan (MYPP), and finalization of a purchase agreement with JEOL for a new-generation electron microscope.

  17. High-temperature electron irradiation and radiation-thermal technology for utilization, purification and production of some metals

    CERN Document Server

    Solovetskii, Y; Lunin, V

    1998-01-01

    High-temperature irradiation by the beam of 1.2-1.6 MeV accelerated electrons has been used for production Pt, Pd, Mo, Co, Cu and Ni from desactivated Pt(Pd)-containing reforming catalysts, molybdenum sulfide hydrodesulphurization catalysts and hydrogenation catalyst waste material. The radiation-induced decomposition of supported Ni(Co)-Mo/Al sub 2 O sub 3 sulfide catalyst and organic fragments of hydrogenation catalyst wastes has been studied. Radiolysis product distributions are shown as function of time (time up to 1,0 h) and temperature (570-1400K). There was made a principle scheme of the first technological unit for radiation-thermal utilization, purification and production of some metals from solid wastes material.

  18. In Situ Monitoring of Microwave Processing of Materials at High Temperatures through Dielectric Properties Measurement

    Directory of Open Access Journals (Sweden)

    Beatriz Garcia-Baños

    2016-05-01

    Full Text Available Microwave-assisted processes have recognized advantages over more conventional heating techniques. However, the effects on the materials’ microstructure are still a matter of study, due to the complexity of the interaction between microwaves and matter, especially at high temperatures. Recently developed advanced microwave instrumentation allows the study of high temperature microwave heating processes in a way that was not possible before. In this paper, different materials and thermal processes induced by microwaves have been studied through the in situ characterization of their dielectric properties with temperature. This knowledge is crucial in several aspects: to analyze the effects of the microwave field on the reaction pathways; to design and optimize microwave-assisted processes, and to predict the behavior of materials leading to repeatable and reliable heating processes, etc.

  19. Auger electron spectroscopy study of oxidation of a PdCr alloy used for high-temperature sensors

    Science.gov (United States)

    Boyd, Darwin L.; Zeller, Mary V.; Vargas-Aburto, Carlos

    1993-01-01

    A Pd-13 wt. percent Cr solid solution is a promising high-temperature strain gage alloy. In bulk form it has a number of properties that are desirable in a resistance strain gage material, such as a linear electrical resistance versus temperature curve to 1000 C and stable electrical resistance in air at 1000 C. However, unprotected fine wire gages fabricated from this alloy perform well only to 600 C. At higher temperatures severe oxidation degrades their electrical performance. In this work Auger electron spectroscopy was used to study the oxidation chemistry of the alloy wires and ribbons. Results indicate that the oxidation is caused by a complex mechanism that is not yet fully understood. As expected, during oxidation, a layer of chromium oxide is formed. This layer, however, forms beneath a layer of metallic palladium. The results of this study have increased the understanding of the oxidation mechanism of Pd-13 wt. percent Cr.

  20. High temperature corrosion of advanced ceramic materials for hot gas filters and heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Crossland, C.E.; Shelleman, D.L.; Spear, K.E. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    1996-08-01

    A vertical flow-through furnace has been built to study the effect of corrosion on the morphology and mechanical properties of ceramic hot gas filters. Sections of 3M Type 203 and DuPont Lanxide SiC-SiC filter tubes were sealed at one end and suspended in the furnace while being subjected to a simulated coal combustion environment at 870{degrees}C. X-ray diffraction and electron microscopy is used to identify phase and morphology changes due to corrosion while burst testing determines the loss of mechanical strength after exposure to the combustion gases. Additionally, a thermodynamic database of gaseous silicon compounds is currently being established so that calculations can be made to predict important products of the reaction of the environment with the ceramics. These thermodynamic calculations provide useful information concerning the regimes where the ceramic may be degraded by material vaporization. To verify the durability and predict lifetime performance of ceramic heat exchangers in coal combustion environments, long-term exposure testing of stressed (internally pressurized) tubes must be performed in actual coal combustion environments. The authors have designed a system that will internally pressurize 2 inch OD by 48 inch long ceramic heat exchanger tubes to a maximum pressure of 200 psi while exposing the outer surface of the tubes to coal combustion gas at the Combustion and Environmental Research Facility (CERF) at the Pittsburgh Energy and Technology Center. Water-cooled, internal o-ring pressure seals were designed to accommodate the existing 6 inch by 6 inch access panels of the CERF. Tubes will be exposed for up to a maximum of 500 hours at temperatures of 2500 and 2600{degrees}F with an internal pressure of 200 psi. If the tubes survive, their retained strength will be measured using the high temperature tube burst test facility at Penn State University. Fractographic analysis will be performed to identify the failure source(s) for the tubes.

  1. AMSAHTS 1990: Advances in Materials Science and Applications of High Temperature Superconductors

    Science.gov (United States)

    Bennett, Larry H. (Editor); Flom, Yury (Editor); Moorjani, Kishin (Editor)

    1991-01-01

    This publication is comprised of abstracts for oral and poster presentations scheduled for AMSAHTS '90. The conference focused on understanding high temperature superconductivity with special emphasis on materials issues and applications. AMSAHTS 90, highlighted the state of the art in fundamental understanding of the nature of high-Tc superconductivity (HTSC) as well as the chemistry, structure, properties, processing and stability of HTSC oxides. As a special feature of the conference, space applications of HTSC were discussed by NASA and Navy specialists.

  2. Review of Mid- to High-Temperature Solar Selective Absorber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, C. E.

    2002-07-01

    This report describes the concentrating solar power (CSP) systems using solar absorbers to convert concentrated sunlight to thermal electric power. It is possible to achieve solar absorber surfaces for efficient photothermal conversion having high solar absorptance (a) for solar radiation and a low thermal emittance (e) at the operational temperature. A low reflectance (?'' 0) at wavelengths (?) 3 mm and a high reflectance (?'' 1) at l 3 mm characterize spectrally selective surfaces. The operational temperature ranges of these materials for solar applications can be categorized as low temperature (T< 100 C), mid-temperature (100 C< T< 400 C), and high-temperature (T> 400 C). High- and mid-temperature applications are needed for CSP applications. For CSP applications, the ideal spectrally selective surface would be low-cost and easy to manufacture, chemically and thermally stable in air at elevated operating temperatures (T= 500 C), and have a solar absorptance= 0.98 and a thermal emittance= 0.05 at 500 C.

  3. Modern electronic materials

    CERN Document Server

    Watkins, John B

    2013-01-01

    Modern Electronic Materials focuses on the development of electronic components. The book first discusses the history of electronic components, including early developments up to 1900, developments up to World War II, post-war developments, and a comparison of present microelectric techniques. The text takes a look at resistive materials. Topics include resistor requirements, basic properties, evaporated film resistors, thick film resistors, and special resistors. The text examines dielectric materials. Considerations include basic properties, evaporated dielectric materials, ceramic dielectri

  4. Process for introducing electrical conductivity into high-temperature polymeric materials

    Science.gov (United States)

    Liepins, R.; Jorgensen, B.S.; Liepins, L.Z.

    1987-08-27

    High-temperature electrically conducting polymers. The in situ reactions: AgNO/sub 3/ + RCHO ..-->.. Ag/sup 0/ + RCOOH and R/sub 3/M ..-->.. M/sup 0/ + 3R, where M = Au or Pt have been found to introduce either substantial bulk or surface conductivity in high- temperature polymers. The reactions involving the R/sub 3/M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone. 3 tabs.

  5. Evaluation of MHD materials for use in high-temperature fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Guidotti, R.

    1978-06-15

    The MHD and high-temperature fuel cell literature was surveyed for data pertaining to materials properties in order to identify materials used in MHD power generation which also might be suitable for component use in high-temperature fuel cells. Classes of MHD-electrode materials evaluated include carbides, nitrides, silicides, borides, composites, and oxides. Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/ used as a reference point to evaluate materials for use in the solid-oxide fuel cell. Physical and chemical properties such as electrical resistivity, coefficient of thermal expansion, and thermodynamic stability toward oxidation were used to screen candidate materials. A number of the non-oxide ceramic MHD-electrode materials appear promising for use in the solid-electrolyte and molten-carbonate fuel cell as anodes or anode constituents. The MHD-insulator materials appear suitable candidates for electrolyte-support tiles in the molten-carbonate fuel cells. The merits and possible problem areas for these applications are discussed and additional needed areas of research are delineated.

  6. Practical reasons for investigating ion transport in high temperature insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Sonder, E.

    1976-07-01

    Practical problems encountered in a number of advanced technology applications, particularly those related to energy conversion, are discussed. Refractory ionic compounds which are abundant and of high melting point are listed, and technological problems are discussed in terms of specific materials problems. The argument is made that basic information concerning transport properties in refractory compounds is lacking to such an extent that it is difficult to design and assess advanced energy generation systems. Technology applications include (a) ceramic nuclear fuels for high temperature fission reactors, (b) high temperature gas turbine blades, (c) insulators in controlled thermonuclear reactors, and (d) magnetohydrodynamic generators. Some of the difficulties inherent in making transport property measurements at high temperatures are also listed.

  7. Graphene, a material for high temperature devices; intrinsic carrier density, carrier drift velocity, and lattice energy

    CERN Document Server

    Yin, Yan; Wang, Li; Jin, Kuijuan; Wang, Wenzhong

    2016-01-01

    Heat has always been a killing matter for traditional semiconductor machines. The underlining physical reason is that the intrinsic carrier density of a device made from a traditional semiconductor material increases very fast with a rising temperature. Once reaching a temperature, the density surpasses the chemical doping or gating effect, any p-n junction or transistor made from the semiconductor will fail to function. Here, we measure the intrinsic Fermi level (|E_F|=2.93k_B*T) or intrinsic carrier density (n_in=3.87*10^6 cm^-2 K^-2*T^2), carrier drift velocity, and G mode phonon energy of graphene devices and their temperature dependencies up to 2400 K. Our results show intrinsic carrier density of graphene is an order of magnitude less sensitive to temperature than those of Si or Ge, and reveal the great potentials of graphene as a material for high temperature devices. We also observe a linear decline of saturation drift velocity with increasing temperature, and identify the temperature coefficients of ...

  8. Electronic materials high-T(sub c) superconductivity polymers and composites structural materials surface science and catalysts industry participation

    Science.gov (United States)

    1988-01-01

    The fifth year of the Center for Advanced Materials was marked primarily by the significant scientific accomplishments of the research programs. The Electronics Materials program continued its work on the growth and characterization of gallium arsenide crystals, and the development of theories to understand the nature and distribution of defects in the crystals. The High Tc Superconductivity Program continued to make significant contributions to the field in theoretical and experimental work on both bulk materials and thin films and devices. The Ceramic Processing group developed a new technique for cladding YBCO superconductors for high current applications in work with the Electric Power Research Institute. The Polymers and Composites program published a number of important studies involving atomistic simulations of polymer surfaces with excellent correlations to experimental results. The new Enzymatic Synthesis of Materials project produced its first fluorinated polymers and successfully began engineering enzymes designed for materials synthesis. The structural Materials Program continued work on novel alloys, development of processing methods for advanced ceramics, and characterization of mechanical properties of these materials, including the newly documented characterization of cyclic fatigue crack propagation behavior in toughened ceramics. Finally, the Surface Science and Catalysis program made significant contributions to the understanding of microporous catalysts and the nature of surface structures and interface compounds.

  9. High-temperature behavior of supported graphene: Electron-phonon coupling and substrate-induced doping

    DEFF Research Database (Denmark)

    Ulstrup, Søren; Bianchi, Marco; Guan, Dandan

    2012-01-01

    The temperature-dependent electronic structure and electron-phonon coupling of weakly doped supported graphene is studied by angle-resolved photoemission spectroscopy and ab initio molecular dynamics simulations. The electron-phonon coupling is found to be extremely weak, reaching the lowest valu...

  10. Advanced High Energy Density Secondary Batteries with Multi‐Electron Reaction Materials

    Science.gov (United States)

    Luo, Rui; Huang, Yongxin; Li, Li

    2016-01-01

    Secondary batteries have become important for smart grid and electric vehicle applications, and massive effort has been dedicated to optimizing the current generation and improving their energy density. Multi‐electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems that meet energy density requirements. An in‐depth understanding of multi‐electron chemistries in terms of the charge transfer mechanisms occuring during their electrochemical processes is necessary and urgent for the modification of secondary battery materials and development of secondary battery systems. In this Review, multi‐electron chemistry for high energy density electrode materials and the corresponding secondary battery systems are discussed. Specifically, four battery systems based on multi‐electron reactions are classified in this review: lithium‐ and sodium‐ion batteries based on monovalent cations; rechargeable batteries based on the insertion of polyvalent cations beyond those of alkali metals; metal–air batteries, and Li–S batteries. It is noted that challenges still exist in the development of multi‐electron chemistries that must be overcome to meet the energy density requirements of different battery systems, and much effort has more effort to be devoted to this. PMID:27840796

  11. Advanced High Energy Density Secondary Batteries with Multi-Electron Reaction Materials.

    Science.gov (United States)

    Chen, Renjie; Luo, Rui; Huang, Yongxin; Wu, Feng; Li, Li

    2016-10-01

    Secondary batteries have become important for smart grid and electric vehicle applications, and massive effort has been dedicated to optimizing the current generation and improving their energy density. Multi-electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems that meet energy density requirements. An in-depth understanding of multi-electron chemistries in terms of the charge transfer mechanisms occuring during their electrochemical processes is necessary and urgent for the modification of secondary battery materials and development of secondary battery systems. In this Review, multi-electron chemistry for high energy density electrode materials and the corresponding secondary battery systems are discussed. Specifically, four battery systems based on multi-electron reactions are classified in this review: lithium- and sodium-ion batteries based on monovalent cations; rechargeable batteries based on the insertion of polyvalent cations beyond those of alkali metals; metal-air batteries, and Li-S batteries. It is noted that challenges still exist in the development of multi-electron chemistries that must be overcome to meet the energy density requirements of different battery systems, and much effort has more effort to be devoted to this.

  12. Spectral evolution of soft x-ray emission from optically thin, high electron temperature platinum plasmas

    Directory of Open Access Journals (Sweden)

    Hiroyuki Hara

    2017-08-01

    Full Text Available The soft x-ray spectra of heavy element plasmas are frequently dominated by unresolved transition array (UTA emission. We describe the spectral evolution of an intense UTA under optically thin conditions in platinum plasmas. The UTA was observed to have a peak wavelength around 4.6 nm at line-of-sight averaged electron temperatures less than 1.4 keV at electron densities of (2.5–7.5 × 1013 cm−3. The UTA spectral structure was due to emission from 4d–4f transitions in highly charged ions with average charge states of q = 20–40. A numerical simulation successfully reproduced the observed spectral behavior.

  13. Spectral evolution of soft x-ray emission from optically thin, high electron temperature platinum plasmas

    Science.gov (United States)

    Hara, Hiroyuki; Ohashi, Hayato; Li, Bowen; Dunne, Padraig; O'Sullivan, Gerry; Sasaki, Akira; Suzuki, Chihiro; Tamura, Naoki; Sakaue, Hiroyuki A.; Kato, Daiji; Murakami, Izumi; Higashiguchi, Takeshi; LHD Experiment Group

    2017-08-01

    The soft x-ray spectra of heavy element plasmas are frequently dominated by unresolved transition array (UTA) emission. We describe the spectral evolution of an intense UTA under optically thin conditions in platinum plasmas. The UTA was observed to have a peak wavelength around 4.6 nm at line-of-sight averaged electron temperatures less than 1.4 keV at electron densities of (2.5-7.5) × 1013 cm-3. The UTA spectral structure was due to emission from 4d-4f transitions in highly charged ions with average charge states of q = 20-40. A numerical simulation successfully reproduced the observed spectral behavior.

  14. Electronic structure of ion arsenic high temperature superconductors studied by angle resolved photoemission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chang [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    The main purpose of the present thesis is to present our ARPES results on the iron arsenic superconductors. As revealed by a series of ARPES measurements on both the AEFe2As2 and the RFeAs(O,F) families (parent compound and carrier-doped systems), the electronic structures of the pnictides are complicated, three dimensional, and closely linked to their superconducting behavior (13; 14; 15; 16; 17; 18; 19). Parent compounds of these materials exhibit the basic hole-electron pocket dual plus an apparent Fermi surface reconstruction caused by long range antiferromagnetism (13; 15). When carriers are introduced, the chemical potential shifts in accordance with the Luttinger theorem and the rigid band shifting picture (13). Importantly, both the appearance and disappearance of the superconducting dome at low and high doping levels have intimate relation with topological changes at the Fermi surfaces, resulting in a specific Fermi topology being favored by superconductivity (15; 16). On the low doping side, superconductivity emerges in the phase diagram once the antiferromagnetic reconstruction disappears below the Fermi level, returning the Fermi surface to its paramagnetic-like appearance. On the high doping side, superconductivity disappears around a doping level at which the central hole pocket vanishes due to increasing electron concentration. Such phenomena are evidence for the governing role the electronic structure plays in their superconducting behavior.

  15. Low-temperature fabrication of high-performance metal oxide thin-film electronics via combustion processing

    Science.gov (United States)

    Kim, Myung-Gil; Kanatzidis, Mercouri G.; Facchetti, Antonio; Marks, Tobin J.

    2011-05-01

    The development of large-area, low-cost electronics for flat-panel displays, sensor arrays, and flexible circuitry depends heavily on high-throughput fabrication processes and a choice of materials with appropriate performance characteristics. For different applications, high charge carrier mobility, high electrical conductivity, large dielectric constants, mechanical flexibility or optical transparency may be required. Although thin films of metal oxides could potentially meet all of these needs, at present they are deposited using slow and equipment-intensive techniques such as sputtering. Recently, solution processing schemes with high throughput have been developed, but these require high annealing temperatures (Tanneal>400 °C), which are incompatible with flexible polymeric substrates. Here we report combustion processing as a new general route to solution growth of diverse electronic metal oxide films (In2O3, a-Zn-Sn-O, a-In-Zn-O, ITO) at temperatures as low as 200 °C. We show that this method can be implemented to fabricate high-performance, optically transparent transistors on flexible plastic substrates.

  16. Computational Search for Two-Dimensional MX2 Semiconductors with Possible High Electron Mobility at Room Temperature

    Directory of Open Access Journals (Sweden)

    Zhishuo Huang

    2016-08-01

    Full Text Available Neither of the two typical two-dimensional materials, graphene and single layer MoS 2 , are good enough for developing semiconductor logical devices. We calculated the electron mobility of 14 two-dimensional semiconductors with composition of MX 2 , where M (=Mo, W, Sn, Hf, Zr and Pt are transition metals, and Xs are S, Se and Te. We approximated the electron phonon scattering matrix by deformation potentials, within which long wave longitudinal acoustical and optical phonon scatterings were included. Piezoelectric scattering in the compounds without inversion symmetry is also taken into account. We found that out of the 14 compounds, WS 2 , PtS 2 and PtSe 2 are promising for logical devices regarding the possible high electron mobility and finite band gap. Especially, the phonon limited electron mobility in PtSe 2 reaches about 4000 cm 2 ·V - 1 ·s - 1 at room temperature, which is the highest among the compounds with an indirect bandgap of about 1.25 eV under the local density approximation. Our results can be the first guide for experiments to synthesize better two-dimensional materials for future semiconductor devices.

  17. Development of heat exchanger for high temperature energy storage with bulk materials

    Science.gov (United States)

    Boura, Cristiano Teixeira; Niederwestberg, Stefan; McLeod, Jacqueline; Herrmann, Ulf; Hoffschmidt, Bernhard

    2016-05-01

    This paper gives a general overview of the concept of a high temperature gas-to-particle heat exchanger, the corresponding test facilities and the results of laboratory tests. A description of the optimal bulk material and separator properties and their influences on the operating conditions is also given. The three phenomena pinning, blistering and blocking could be observed during the tests and were analysed in more detail using simulation software.

  18. Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    John G. Cowie; Edwin F. Brush, Jr.; Dale T. Peters; Stephen P. Midson; Darryl J. Van Son

    2003-05-01

    The objective of the study, Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency, was to support the Copper Development Association (CDA) in its effort to design, fabricate and demonstrate mold technologies designed to withstand the copper motor rotor die casting environment for an economically acceptable life. The anticipated result from the compiled data and tests were to: (1) identify materials suitable for die casting copper, (2) fabricate motor rotor molds and (3) supply copper rotor motors for testing in actual compressor systems. Compressor manufacturers can apply the results to assess the technical and economical viability of copper rotor motors.

  19. Outward transport of high-temperature materials around the midplane of the solar nebula.

    Science.gov (United States)

    Ciesla, Fred J

    2007-10-26

    The Stardust samples collected from Comet 81P/Wild 2 indicate that large-scale mixing occurred in the solar nebula, carrying materials from the hot inner regions to cooler environments far from the Sun. Similar transport has been inferred from telescopic observations of protoplanetary disks around young stars. Models for protoplanetary disks, however, have difficulty explaining the observed levels of transport. Here I report the results of a new two-dimensional model that shows that outward transport of high-temperature materials in protoplanetary disks is a natural outcome of disk formation and evolution. This outward transport occurs around the midplane of the disk.

  20. A review of advanced metallic and ceramic materials suitable for high temperature use in space structures

    Science.gov (United States)

    Bashford, David

    Spacecraft, satellites and launch vehicles require efficient, lightweight structural materials. At present, the structural requirements can be largely met by aluminium alloys and polymeric matrix composites based on carbon fibres. However, increasingly there will be a need to specify materials capable of sustaining operational use at temperatures in excess of 250°C and towards 2000°C. Ambitious spaceplane projects such as Hermes, HOTOL, Sanger, HOPE and NASP have highlighted this need. Within the operational temperature band 250°C to 2000°C various metallic and ceramic materials are appropriate for consideration, either in alloy or composite form. This review paper identifies the status of technology on the following: i) Aluminium and titanium alloys and their composites. ii) Superalloys and their composites. iii) Carbon, glass-ceramic and ceramic matrix composites. The development of more weight efficient and thermally stable metallic and ceramic materials has centred on a number of key areas (1). For metallics, improved alloy composition and grain refinement from Rapidly Solidified Powders have given improvements in strength retention at high temperatures (a). The introduction of reinforcements, either particulate, whisker or continuous fibre, have improved the basic alloys by reducing density, increasing stiffness and strength and extending thermal capabilities. Monolithic ceramics possess thermal stability but are inherently brittle and crack sensitive. The addition of ceramic fibres and whiskers has the effect of modifying fracture characteristics by introducing "pseudo-ductility" to raise apparent toughness. In the foreseeable future the emerging high temperature materials will find uses in: Spaceplane substructures and control surfaces; Thermal protection systems and insulation; Propulsion plants and thruster units; Air breathing engines.

  1. Production of advanced materials by methods of self-propagating high-temperature synthesis

    CERN Document Server

    Tavadze, Giorgi F

    2013-01-01

    This translation from the original Russian book outlines the production of a variety of materials by methods of self-propagating high-temperature synthesis (SHS). The types of materials discussed include: hard, refractory, corrosion and wear-resistant materials, as well as other advanced and speciality materials. The authors address the issue of optimal parameters for SHS reactions occurring during processes involving a preliminary metallothermic reduction stage, and they calculate this using thermodynamic approaches. In order to confirm the effectiveness of this approach, the authors describe experiments focussing on the synthesis of elemental crysalline boron, boron carbides and nitrides. Other parts of this brief include theoretical and experimental results on single-stage production of hard alloys on the basis of titanium and zirconium borides, as well as macrokinetics of degassing and compaciton of SHS-products.This brief is suitable for academics, as well as those working in industrial manufacturing com...

  2. High temperature corrosion of superheater materials for power production through biomass

    Energy Technology Data Exchange (ETDEWEB)

    Gotthjaelp, K.; Broendsted, P. [Forskningscenter Risoe (Denmark); Jansen, P. [FORCE Institute (Denmark); Montgomery, M.; Nielsen, K.; Maahn, E. [Technical Univ. of Denmark, Corrosion and Surface Techn. Inst. of Manufacturing Engineering (Denmark)

    1996-08-01

    The aim of the present study has been to establish a fundamental knowledge of the corrosion mechanisms acting on materials for use in biomass fired power plants. The knowledge is created based on laboratory exposures of selected materials in well-defined corrosive gas environments. The experiments using this facility includes corrosion studies of two types of high temperature resistant steels, Sanvik 8LR30 (18Cr 10Ni Ti) and Sanicro 28 (27Cr 31Ni 4Mo), investigated at 600 deg. C in time intervals up to 300 hours. The influence of HCl (200 ppm) and of SO{sub 2} (300 ppm) on the corrosion progress has been investigated. In addition the corrosion behaviour of the same materials was investigated after having been exposed under a cover of ash in air in a furnace at temperatures of 525 deg. C, 600 deg. C, and 700 deg. C. The ashes utilised are from a straw fired power plant and a synthetic ash composed of potassium chloride (KCl) and potassium sulphate (K{sub 2}SO{sub 4}). Different analysis techniques to characterise the composition of the ash coatings have been investigated in order to judge the reliability and accuracy of the SEM-EDX method. The results are considered as an important step towards a better understanding of the high temperature corrosion under the conditions found in biomass fired power plants. One of the problems to solve in a suggested subsequent project is to combine the effect of the aggressive gases (SO{sub 2} and HCl) and the active ash coatings on high temperature corrosion of materials. (EG) 20 refs.

  3. Maintaining the structure of templated porous materials for reactive and high-temperature applications.

    Science.gov (United States)

    Rudisill, Stephen G; Wang, Zhiyong; Stein, Andreas

    2012-05-15

    Nanoporous and nanostructured materials are becoming increasingly important for advanced applications involving, for example, bioactive materials, catalytic materials, energy storage and conversion materials, photonic crystals, membranes, and more. As such, they are exposed to a variety of harsh environments and often experience detrimental morphological changes as a result. This article highlights material limitations and recent advances in porous materials--three-dimensionally ordered macroporous (3DOM) materials in particular--under reactive or high-temperature conditions. Examples include systems where morphological changes are desired and systems that require an increased retention of structure, surface area, and overall material integrity during synthesis and processing. Structural modifications, changes in composition, and alternate synthesis routes are explored and discussed. Improvements in thermal or structural stability have been achieved by the isolation of nanoparticles in porous structures through spatial separation, by confinement in a more thermally stable host, by the application of a protective surface or an adhesive interlayer, by alloy or solid solution formation, and by doping to induce solute drag.

  4. Multilayer "Steel/Vanadium Alloy/Steel" Hybrid Material Obtained by High-Pressure Torsion at Different Temperatures

    Science.gov (United States)

    Rogachev, S. O.; Nikulin, S. A.; Rozhnov, A. B.; Khatkevich, V. M.; Nechaykina, T. A.; Gorshenkov, M. V.; Sundeev, R. V.

    2017-12-01

    The severe plastic deformation (SPD) method for joining dissimilar metal materials to obtain a multilayer hybrid material having an ultrafine or nanoscale structure was proposed. A nanostructured multilayer "0.08C-18Cr-0.5Ti steel/V-10Ti-5Cr alloy/0.08C-18Cr-0.5Ti steel" hybrid material was obtained by high-pressure torsion (HPT) at different temperatures. The analysis of the structure of the hybrid material and its components was carried out by the methods of transmission and scanning electron microscopies. The distribution of chemical elements in the cross section of the hybrid material was studied by X-ray microanalysis. The microhardness was measured to estimate the hybrid material hardening after HPT. Tight joint zones between the layers of the hybrid material were formed during HPT. The fragmentation of the steel and vanadium alloy layers was observed, and the "mixing" of the layers occurred after HPT at 293 K and 473 K (20 °C and 200 °C). A smoother interface between the layers was observed after HPT at 673 K (400 °C). The significant hardening (2.0 to 3.5×) of each layer of the hybrid material was observed as a result of HPT.

  5. Research for Brazing Materials of High-Temperature Thermoelectric Modules with CoSb3 Thermoelectric Materials

    Science.gov (United States)

    Lee, Yu Seong; Kim, Suk Jun; Kim, Byeong Geun; Lee, Soonil; Seo, Won-Seon; Kim, Il-Ho; Choi, Soon-Mok

    2017-05-01

    Metallic glass (MG) can be a candidate for an alternative brazing material of high-temperature thermoelectric modules, since we can expect both a lower brazing temperature and a high operating temperature for the junction from the MG brazers. Another advantage of MG powders is their outstanding oxidation resistance, namely, high-temperature durability in atmosphere. We fabricated three compositions of Al-based MGs—Al-Y-Ni, Al-Y-Ni-Co, and Al-Y-Ni-Co-La—by using the melt spinning process, and their T gs were 273°C, 264°C, and 249°C, respectively. The electrical resistivity of the Al-Y-Ni MG ribbon dropped significantly after annealing at 300°C. The electrical resistivity of crystallized Al-Y-Ni reduced down to 0.03 mΩ cm, which is an order of magnitude lower than that of the amorphous one. After the MG ribbons were pulverized to sub-100 μm, the average particle size was about 400 μm.

  6. High-Purity Semiconducting Single-Walled Carbon Nanotubes: A Key Enabling Material in Emerging Electronics.

    Science.gov (United States)

    Lefebvre, Jacques; Ding, Jianfu; Li, Zhao; Finnie, Paul; Lopinski, Gregory; Malenfant, Patrick R L

    2017-10-17

    Semiconducting single-walled carbon nanotubes (sc-SWCNTs) are emerging as a promising material for high-performance, high-density devices as well as low-cost, large-area macroelectronics produced via additive manufacturing methods such as roll-to-roll printing. Proof-of-concept demonstrations have indicated the potential of sc-SWCNTs for digital electronics, radiofrequency circuits, radiation hard memory, improved sensors, and flexible, stretchable, conformable electronics. Advances toward commercial applications bring numerous opportunities in SWCNT materials development and characterization as well as fabrication processes and printing technologies. Commercialization in electronics will require large quantities of sc-SWCNTs, and the challenge for materials science is the development of scalable synthesis, purification, and enrichment methods. While a few synthesis routes have shown promising results in making near-monochiral SWCNTs, gram quantities are available only for small-diameter sc-SWCNTs, which underperform in transistors. Most synthesis routes yield mixtures of SWCNTs, typically 30% metallic and 70% semiconducting, necessitating the extraction of sc-SWCNTs from their metallic counterparts in high purity using scalable postsynthetic methods. Numerous routes to obtain high-purity sc-SWCNTs from raw soot have been developed, including density-gradient ultracentrifugation, chromatography, aqueous two-phase extraction, and selective DNA or polymer wrapping. By these methods (termed sorting or enrichment), >99% sc-SWCNT content can be achieved. Currently, all of these approaches have drawbacks and limitations with respect to electronics applications, such as excessive dilution, expensive consumables, and high ionic impurity content. Excess amount of dispersant is a common challenge that hinders direct inclusion of sc-SWCNTs into electronic devices. At present, conjugated polymer extraction may represent the most practical route to sc-SWCNTs. By the use of

  7. Influence of the starting materials on performance of high temperature oxide fuel cells devices

    Directory of Open Access Journals (Sweden)

    Emília Satoshi Miyamaru Seo

    2004-03-01

    Full Text Available High temperature solid oxide fuel cells (SOFCs offer an environmentally friendly technology to convert gaseous fuels such as hydrogen, natural gas or gasified coal into electricity at high efficiencies. Besides the efficiency, higher than those obtained from the traditional energy conversion systems, a fuel cell provides many other advantages like reliability, modularity, fuel flexibility and very low levels of NOx and SOx emissions. The high operating temperature (950-1000 °C used by the current generation of the solid oxide fuel cells imposes severe constraints on materials selection in order to improve the lifetime of the cell. Besides the good electrical, electrochemical, mechanical and thermal properties, the individual cell components must be stable under the fuel cell operating atmospheres. Each material has to perform not only in its own right but also in conjunction with other system components. For this reason, each cell component must fulfill several different criteria. This paper reviews the materials and the methods used to fabricate the different cell components, such as the cathode, the electrolyte, the anode and the interconnect. Some remarkable results, obtained at IPEN (Nuclear Energy Research Institute in São Paulo, have been presented.

  8. High-temperature thermal storage systems for advanced solar receivers materials selections

    Science.gov (United States)

    Wilson, D. F.; Devan, J. H.; Howell, M.

    1990-01-01

    Advanced space power systems that use solar energy and Brayton or Stirling heat engines require thermal energy storage (TES) systems to operate continuously through periods of shade. The receiver storage units, key elements in both Brayton and Stirling systems, are designed to use the latent heat of fusion of phase-change materials (PCMs). The power systems under current consideration for near-future National Aeronautics and Space Administration space missions require working fluid temperatures in the 1100 to 1400 K range. The PCMs under current investigation that gave liquid temperatures within this range are the fluoride family of salts. However, these salts have low thermal conductivity, which causes large temperature gradients in the storage systems. Improvements can be obtained, however, with the use of thermal conductivity enhancements or metallic PCMs. In fact, if suitable containment materials can be found, the use of metallic PCMs would virtually eliminate the orbit associated temperature variations in TES systems. The high thermal conductivity and generally low volume change on melting of germanium and alloys based on silicon make them attractive for storage of thermal energy in space power systems. An approach to solving the containment problem, involving both chemical and physical compatibility, preparation of NiSi/NiSi2, and initial results for containment of germanium and NiSi/NiSi2, are presented.

  9. Electron Temperature and Density in Local Helicity Injection and High betat Plasmas

    Science.gov (United States)

    Schlossberg, David J.

    Tokamak startup in a spherical torus (ST) and an ST-based fusion nuclear science facility can greatly benefit from using non-inductive methods. The Pegasus Toroidal Experiment has developed a non-inductive startup technique using local helicity injection (LHI). Electron temperature, T e(r), and density, ne( r), profiles during LHI are unknown. These profiles are critical for understanding both the physics of the injection and relaxation mechanisms, as well as for extrapolating this technique to larger devices. A new Thomson scattering system has been designed, installed, and used to characterize Te(r, t) and ne(r, t) during LHI. The diagnostic leverages new technology in image intensified CCD cameras, high-efficiency diffraction gratings, and reliable Nd:YAG lasers. Custom systems for stray light mitigation, fast shuttering, and precision timing have been developed and implemented. The overall system provides a low-maintenance, economic, and effective means to explore novel physics regimes in Pegasus. Electron temperature and density profiles during LHI have been measured for the first time. Results indicate Te(r) peaked in the core of plasmas, and sustained while plasmas are coupled to injection drive. Electron densities also peak near the core of the tokamak, up to local values of n e ˜ 1.5 x 1019 m -3. A comparison of Te( r, t) has been made between discharges with dominant drive voltage from induction versus helicity injection. In both cases Te ( r, t) profiles remain peaked, with values for Te ,max > 150 eV in dominantly helicity-driven plasmas using high-field side LHI. Sustained values of betat ˜ 100% have been demonstrated in a tokamak for the first time. Plasmas are created and driven entirely non-solenoidally, and exhibit MHD stability. Measured temperature and density profiles are used to constrain magnetic equilibrium reconstructions, which calculate 80% ramp-down. For a continued decrease in the toroidal field these plasmas disrupt near the ideal MHD

  10. In Situ Measurements of Spectral Emissivity of Materials for Very High Temperature Reactors

    Energy Technology Data Exchange (ETDEWEB)

    G. Cao; S. J. Weber; S. O. Martin; T. L. Malaney; S. R. Slattery; M. H. Anderson; K. Sridharan; T. R. Allen

    2011-08-01

    An experimental facility for in situ measurements of high-temperature spectral emissivity of materials in environments of interest to the gas-cooled very high temperature reactor (VHTR) has been developed. The facility is capable of measuring emissivities of seven materials in a single experiment, thereby enhancing the accuracy in measurements due to even minor systemic variations in temperatures and environments. The system consists of a cylindrical silicon carbide (SiC) block with seven sample cavities and a deep blackbody cavity, a detailed optical system, and a Fourier transform infrared spectrometer. The reliability of the facility has been confirmed by comparing measured spectral emissivities of SiC, boron nitride, and alumina (Al2O3) at 600 C against those reported in literature. The spectral emissivities of two candidate alloys for VHTR, INCONEL{reg_sign} alloy 617 (INCONEL is a registered trademark of the Special Metals Corporation group of companies) and SA508 steel, in air environment at 700 C were measured.

  11. Quick high-temperature hydrothermal synthesis of mesoporous materials with 3D cubic structure for the adsorption of lysozyme.

    Science.gov (United States)

    Lawrence, Geoffrey; Baskar, Arun V; El-Newehy, Mohammed H; Cha, Wang Soo; Al-Deyab, Salem S; Vinu, Ajayan

    2015-04-01

    Three-dimensional cage-like mesoporous FDU-12 materials with large tuneable pore sizes ranging from 9.9 to 15.6 nm were prepared by varying the synthesis temperature from 100 to 200 °C for the aging time of just 2 h using a tri-block copolymer F-127(EO106PO70EO106) as the surfactant and 1,3,5-trimethyl benzene as the swelling agent in an acidic condition. The mesoporous structure and textural features of FDU-12-HX (where H denotes the hydrothermal method and X denotes the synthesis temperature) samples were elucidated and probed using x-ray diffraction, N2 adsorption, (29)Si magic angle spinning nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. It has been demonstrated that the aging time can be significantly reduced from 72 to 2 h without affecting the structural order of the FDU-12 materials with a simple adjustment of the synthesis temperature from 100 to 200 °C. Among the materials prepared, the samples prepared at 200 °C had the highest pore volume and the largest pore diameter. Lysozyme adsorption experiments were conducted over FDU-12 samples prepared at different temperatures in order to understand their biomolecule adsorption capacity, where the FDU-12-HX samples displayed high adsorption performance of 29 μmol g(-1) in spite of shortening the actual synthesis time from 72 to 2 h. Further, the influence of surface area, pore volume and pore diameter on the adsorption capacity of FDU-12-HX samples has been investigated and results are discussed in correlation with the textural parameters of the FDU-12-HX and other mesoporous adsorbents including SBA-15, MCM-41, KIT-5, KIT-6 and CMK-3.

  12. On the harmonic technique to measure electron temperature with high time resolution

    Science.gov (United States)

    Boedo, J. A.; Gray, D.; Conn, R. W.; Luong, P.; Schaffer, M.; Ivanov, R. S.; Chernilevsky, A. V.; Van Oost, G.

    1999-07-01

    A detailed study of the harmonic technique, which exploits the generation of harmonics resulting from excitation of the nonlinearity of the single Langmuir probe characteristic, is presented. The technique is used to measure electron temperature and its fluctuations in tokamak plasmas and the technical issues relevant to extending the technique to high bandwidth (200 kHz) are discussed. The technique has been implemented in a fast reciprocating probe in the TEXTOR tokamak, gaining the ability to study denser and hotter plasmas than previously possible. A corrected analytical expression is derived for the harmonic currents. Measurement of the probe current by inductive pickup is introduced to improve electrical isolation and bandwidth. The temperature profiles in the boundary plasma of TEXTOR have been measured with high spatial (˜2 mm) and temporal (200 kHz) resolution and compared to those obtained with a double probe. The exact expansion of the probe characteristic in terms of Bessel functions is compared to a computationally efficient power series. Various aspects of the interpretation of the measurement are discussed such as the influence of plasma potential and density fluctuations. The technique is well suited to study fast phenomena such as transient plasma discharges or turbulence and turbulent transport in plasmas.

  13. Structural materialization of stainless steel molds and dies by the low temperature high density plasma nitriding

    Directory of Open Access Journals (Sweden)

    Aizawa Tatsuhiko

    2015-01-01

    Full Text Available Various kinds of stainless steels have been widely utilized as a mold substrate material for injection molding and as a die for mold-stamping and direct stamping processes. Since they suffered from high temperature transients and thermal cycles in practice, they must be surface-treated by dry and wet coatings, or, by plasma nitriding. Martensitic stainless steel mold was first wet plated by the nickel phosphate (NiP, which was unstable at the high temperature stamping condition; and, was easy to crystalize or to fracture by itself. This issue of nuisance significantly lowered the productivity in fabrication of optical elements at present. In the present paper, the stainless steel mold was surface-treated by the low-temperature plasma nitriding. The nitrided layer by this surface modification had higher nitrogen solute content than 4 mass%; the maximum solid-solubility of nitrogen is usually 0.1 mass% in the equilibrium phase diagram. Owing to this solid-solution with high nitrogen concentration, the nitrided layer had high hardness of 1400 Hv within its thickness of 40 μm without any formation of nitrides after 14.4 ks plasma nitriding at 693 K. This nitrogen solid-solution treated stainless steel had thermal resistivity even at the mold-stamping conditions up to 900 K.

  14. High Temperature Solid Lubricant Materials for Heavy Duty and Advanced Heat Engines

    Science.gov (United States)

    Dellacorte, C.; Wood, J. C.

    1994-01-01

    Advanced engine designs incorporate higher mechanical and thermal loading to achieve efficiency improvements. This approach often leads to higher operating temperatures of critical sliding elements (e.g. piston ring/cylinder wall contacts and valve guides) which compromise the use of conventional and even advanced synthetic liquid lubricants. For these applications solid lubricants must be considered. Several novel solid lubricant composites and coatings designated PS/PM200 have been employed to dry and marginally oil lubricated contacts in advanced heat engines. These applications include cylinder kits of heavy duty diesels, and high temperature Stirling engines, sidewall seals of rotary engines, and various exhaust valve and exhaust component applications. This paper describes the tribological and thermophysical properties of these tribomaterials and reviews the results of applying them to engine applications. Other potential tribological materials and applications are also discussed with particular emphasis on heavy duty and advanced heat engines.

  15. A High Temperature Cyclic Oxidation Data Base for Selected Materials Tested at NASA Glenn Research Center

    Science.gov (United States)

    Barrett, Charles A.

    2003-01-01

    The cyclic oxidation test results for some 1000 high temperature commercial and experimental alloys have been collected in an EXCEL database. This database represents over thirty years of research at NASA Glenn Research Center in Cleveland, Ohio. The data is in the form of a series of runs of specific weight change versus time values for a set of samples tested at a given temperature, cycle time, and exposure time. Included on each run is a set of embedded plots of the critical data. The nature of the data is discussed along with analysis of the cyclic oxidation process. In addition examples are given as to how a set of results can be analyzed. The data is assembled on a read-only compact disk which is available on request from Materials Durability Branch, NASA Glenn Research Center, Cleveland, Ohio.

  16. Visualisation of high temperature magnetisation states in magnetite grains using off-axis electron holography

    Science.gov (United States)

    Almeida, T. P.; Muxworthy, A. R.; Kovács, A.; Williams, W.; Dunin-Borkowski, R. E.

    2015-10-01

    The production of a synthetic basalt comprising Fe3O4 grains (∼ 50 nm to ∼ 500 nm), via a glass ceramic method, has been confirmed using transmission electron microscopy and X-ray diffractometry. Off-axis electron holography combined with in situ heating allowed for the visualisation of non-uniform vortex states present in saturation remanent structures, and their variation approaching the Curie temperature; determined separately by bulk thermomagnetic measurements.

  17. Recycling of hazardous solid waste material using high-temperature solar process heat

    Energy Technology Data Exchange (ETDEWEB)

    Schaffner, B.; Meier, A.; Wuillemin, D.; Hoffelner, W.; Steinfeld, A.

    2003-03-01

    A novel high-temperature solar chemical reactor is proposed for the thermal recycling of hazardous solid waste material using concentrated solar power. A 10 kW solar reactor prototype was designed and tested for the carbothermic reduction of electric arc furnace dusts (EAFD). The reactor was subjected to mean solar flux intensities of 2000 kW/m2 and operated in both batch and continuous mode within the temperature range 1120-1400 K. Extraction of up to 99% and 90% of the Zn originally contained in the EAFD was achieved in the residue for the batch and continuous solar experiments, respectively. The condensed off-gas products consisted mainly of Zn, Pb, and Cl. No ZnO was detected when the O{sub 2} concentration remained below 2 vol.-%. The use of concentrated solar energy as the source of process heat offers the possibility of converting hazardous solid waste material into valuable commodities for processes in closed and sustainable material cycles. (author)

  18. High Temperature Corrosion of Superheater Materials for Power Production through Biomass

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel; Nielsen, Karsten agersted

    The aim of the present study has been to establish a fundamental knowledge of the corrosion mechanisms acting on materials for use in biomass fired power plants. The knowledge is created based on laboratory exposures on selected materials in well-defined corrosive gas environments. An experimental...... plant boiler. The experiments using this facility includes corrosion studies of two types of high temperature resistant steels, Sandvik 8LR30 (18Cr 10Ni Ti) and Sanicro 28 (27Cr 31Ni 4Mo)investigated at 600Cin time intervals up to 300 hours. The influence of HCl (200ppm) and of SO2 (300 ppm......) on the corrosion progress has been investigated.In addition the corrosion behaviour of the same materials was investigated after having been exposed under a cover of ash in air in a furnace at temperatures of 525C, 600C and 700C. The ashes utilised are from a straw-fired power plant and a synthetic ash composed...

  19. Transformational Electronics: Towards Flexible Low-Cost High Mobility Channel Materials

    KAUST Repository

    Nassar, Joanna M.

    2014-05-01

    For the last four decades, Si CMOS technology has been advancing with Moore’s law prediction, working itself down to the sub-20 nm regime. However, fundamental problems and limitations arise with the down-scaling of transistors and thus new innovations needed to be discovered in order to further improve device performance without compromising power consumption and size. Thus, a lot of studies have focused on the development of new CMOS compatible architectures as well as the discovery of new high mobility channel materials that will allow further miniaturization of CMOS transistors and improvement of device performance. Pushing the limits even further, flexible and foldable electronics seem to be the new attractive topic. By being able to make our devices flexible through a CMOS compatible process, one will be able to integrate hundreds of billions of more transistors in a small volumetric space, allowing to increase the performance and speed of our electronics all together with making things thinner, lighter, smaller and even interactive with the human skin. Thus, in this thesis, we introduce for the first time a cost-effective CMOS compatible approach to make high-k/metal gate devices on flexible Germanium (Ge) and Silicon-Germanium (SiGe) platforms. In the first part, we will look at the various approaches in the literature that has been developed to get flexible platforms, as well as we will give a brief overview about epitaxial growth of Si1-xGex films. We will also examine the electrical properties of the Si1-xGex alloys up to Ge (x=1) and discuss how strain affects the band structure diagram, and thus the mobility of the material. We will also review the material growth properties as well as the state-of-the-art results on high mobility metal-oxide semiconductor capacitors (MOSCAPs) using strained SiGe films. Then, we will introduce the flexible process that we have developed, based on a cost-effective “trench-protect-release-reuse” approach, utilizing

  20. Studies on mechanical high-temperature properties of materials with sprayed coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pisarenko, G.S.; Ljasenko, B.A.; Zygylev, O.V.

    1983-03-01

    The results of studies on the tensile strength, creep behaviour and durability in the temperature range from 1 700 to 2 400 K of surface-coated molybdenum samples for experimental times <=10h. are reported here. Monolayer coatings based on molybdenum disilicide and bilayer coatings consisting of a ground coating of molybdenum disilicide and a cover layer of glass and high-melting oxides are used as protective coatings. The ground coating is formed by a thermodiffusion process and the cover coating formed with the aid of a plasma spaying technique. A suggestion is made for optimizing the properties of the combination basic material/coating by taking as criterium the heat resistance and standard parameters for the properties of the basic material and the coating, together with their adhesion resistance.

  1. Performance of a Novel Hydrophobic Mesoporous Material for High Temperature Catalytic Oxidation of Naphthalene

    Directory of Open Access Journals (Sweden)

    Guotao Zhao

    2014-01-01

    Full Text Available A high surface area, hydrophobic mesoporous material, MFS, has been successfully synthesized by a hydrothermal synthesis method using a perfluorinated surfactant, SURFLON S-386, as the single template. N2 adsorption and TEM were employed to characterize the pore structure and morphology of MFS. Static water adsorption test indicates that the hydrophobicity of MFS is significantly higher than that of MCM-41. XPS and Py-GC/MS analysis confirmed the existence of perfluoroalkyl groups in MFS which led to its high hydrophobicity. MFS was used as a support for CuO in experiments of catalytic combustion of naphthalene, where it showed a significant advantage over MCM-41 and ZSM-5. SEM was helpful in understanding why CuO-MFS performed so well in the catalytic combustion of naphthalene. Experimental results indicated that MFS was a suitable support for catalytic combustion of large molecular organic compounds, especially for some high temperature catalytic reactions when water vapor was present.

  2. Modified T-history method for measuring thermophysical properties of phase change materials at high temperature

    Science.gov (United States)

    Omaraa, Ehsan; Saman, Wasim; Bruno, Frank; Liu, Ming

    2017-06-01

    Latent heat storage using phase change materials (PCMs) can be used to store large amounts of energy in a narrow temperature difference during phase transition. The thermophysical properties of PCMs such as latent heat, specific heat and melting and solidification temperature need to be defined at high precision for the design and estimating the cost of latent heat storage systems. The existing laboratory standard methods, such as differential thermal analysis (DTA) and differential scanning calorimetry (DSC), use a small sample size (1-10 mg) to measure thermophysical properties, which makes these methods suitable for homogeneous elements. In addition, this small amount of sample has different thermophysical properties when compared with the bulk sample and may have limitations for evaluating the properties of mixtures. To avoid the drawbacks in existing methods, the temperature - history (T-history) method can be used with bulk quantities of PCM salt mixtures to characterize PCMs. This paper presents a modified T-history setup, which was designed and built at the University of South Australia to measure the melting point, heat of fusion, specific heat, degree of supercooling and phase separation of salt mixtures for a temperature range between 200 °C and 400 °C. Sodium Nitrate (NaNO3) was used to verify the accuracy of the new setup.

  3. Study on high temperature design methodology of heat-resistant materials for GEN-IV systems

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Seog; Kim, D. W.; Kim, S. H.; Kim, W. G.; Kim, J. H.; Park, D. G.; Yoon, J. H.; Lee, H. Y.; Hing, J. H

    2005-08-15

    Analysis of the existing high temperature design and assessment codes such as US(ASME-NH,Draft Code Case for Alloy 617), France(RCC-MR), UK(R5), Japan(BDS/DDS/FDS) for Gen IV reactor structure has been carried out. In addition the scope and fields for research and development is needed in the future have been defined. For assessing the high temperature creep cracks, time dependent fracture mechanics (TDFM) parameters of the C and Ct were analyzed. The creep propagation data were obtained from the creep crack growth tests for type 316LN stainless steels, and creep crack growth testing machine for Gen-IV system up to 950 .deg. C was set up. Damage mechanism and causes for creep-fatigue were investigated. The difference between prediction creep-fatigue life and experimental life were investigated. Material properties for analysis creep-fatigue damage were recommended. The assessment procedure (Draft) on creep-fatigue crack initiation has been developed based on the technical appendix A16 of French RCC-MR code. Ultrasonic wave signal against creep ruptured specimens of type 316LN stainless steel was obtained. It was identified that creep damage can be evaluated by ultrasonic method. The NDT techniques evaluated include Barkhausen noise, magnetic hysteresis parameters, positron annihilation, X-ray diffraction and small angle neutron scattering. Experimental procedure and evaluation method of material integrity were developed through the fracture toughness test of Cr-Mo steel.

  4. Application of high temperature phase change materials for improved efficiency in waste-to-energy plants.

    Science.gov (United States)

    Dal Magro, Fabio; Xu, Haoxin; Nardin, Gioacchino; Romagnoli, Alessandro

    2018-03-01

    This study reports the thermal analysis of a novel thermal energy storage based on high temperature phase change material (PCM) used to improve efficiency in waste-to-energy plants. Current waste-to-energy plants efficiency is limited by the steam generation cycle which is carried out with boilers composed by water-walls (i.e. radiant evaporators), evaporators, economizers and superheaters. Although being well established, this technology is subjected to limitations related with high temperature corrosion and fluctuation in steam production due to the non-homogenous composition of solid waste; this leads to increased maintenance costs and limited plants availability and electrical efficiency. The proposed solution in this paper consists of replacing the typical refractory brick installed in the combustion chamber with a PCM-based refractory brick capable of storing a variable heat flux and to release it on demand as a steady heat flux. By means of this technology it is possible to mitigate steam production fluctuation, to increase temperature of superheated steam over current corrosion limits (450°C) without using coated superheaters and to increase the electrical efficiency beyond 34%. In the current paper a detailed thermo-mechanical analysis has been carried out in order to compare the performance of the PCM-based refractory brick against the traditional alumina refractory bricks. The PCM considered in this paper is aluminium (and its alloys) whereas its container consists of high density ceramics (such as Al 2 O 3 , AlN and Si 3 N 4 ); the different coefficient of linear thermal expansion for the different materials requires a detailed thermo-mechanical analysis to be carried out to ascertain the feasibility of the proposed technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Facility for assessing spectral normal emittance of solid materials at high temperature.

    Science.gov (United States)

    Mercatelli, Luca; Meucci, Marco; Sani, Elisa

    2015-10-10

    Spectral emittance is a key topic in the study of new compositions, depositions, and mechanical machining of materials for solar absorption and for renewable energies in general. The present work reports on the realization and testing of a new experimental facility for the measurement of directional spectral emittance in the range of 2.5-20 μm. Our setup provides emittance spectral information in a completely controlled environment at medium-high temperatures up to 1200 K. We describe the layout and first tests on the device, comparing the results obtained for hafnium carbide and tantalum diboride ultrarefractory ceramic samples to previous quasi-monochromatic measurements carried out in the PROMES-CNRS (PROcedes, Materiaux et Energie Solaire- Centre National de la Recherche Scientifique, France) solar furnace, obtaining a good agreement. Finally, to assess the reliability of the widely used approach of estimating the spectral emittance from room-temperature reflectance spectrum, we compared the calculation in the 2.5-17 μm spectral range to the experimental high-temperature spectral emittance, obtaining that the spectral trend of calculated and measured curves is similar but the calculated emittance underestimates the measured value.

  6. Very High Temperature Reactor (VHTR) Survey of Materials Research and Development Needs to Support Early Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Eric Shaber; G. Baccaglini; S. Ball; T. Burchell; B. Corwin; T. Fewell; M. Labar; P. MacDonald; P. Rittenhouse; Russ Vollam; F. Southworth

    2003-01-01

    The VHTR reference concept is a helium-cooled, graphite moderated, thermal neutron spectrum reactor with an outlet temperature of 1000 C or higher. It is expected that the VHTR will be purchased in the future as either an electricity producing plant with a direct cycle gas turbine or a hydrogen producing (or other process heat application) plant. The process heat version of the VHTR will require that an intermediate heat exchanger (IHX) and primary gas circulator be located in an adjoining power conversion vessel. A third VHTR mission - actinide burning - can be accomplished with either the hydrogen-production or gas turbine designs. The first ''demonstration'' VHTR will produce both electricity and hydrogen using the IHX to transfer the heat to either a hydrogen production plant or the gas turbine. The plant size, reactor thermal power, and core configuration will be designed to assure passive decay heat removal without fuel damage during accidents. The fuel cycle will be a once-through very high burnup low-enriched uranium fuel cycle. The purpose of this report is to identify the materials research and development needs for the VHTR. To do this, we focused on the plant design described in Section 2, which is similar to the GT-MHR plant design (850 C core outlet temperature). For system or component designs that present significant material challenges (or far greater expense) there may be some viable design alternatives or options that can reduce development needs or allow use of available (cheaper) materials. Nevertheless, we were not able to assess those alternatives in the time allotted for this report and, to move forward with this material research and development assessment, the authors of this report felt that it was necessary to use a GT-MHR type design as the baseline design.

  7. FOREX-A Fiber Optics Diagnostic System For Study Of Materials At High Temperatures And Pressures

    Science.gov (United States)

    Smith, D. E.; Roeske, F.

    1983-03-01

    We have successfully fielded a Fiber Optics Radiation EXperiment system (FOREX) designed for measuring material properties at high temperatures and pressures on an underground nuclear test. The system collects light from radiating materials and transmits it through several hundred meters of optical fibers to a recording station consisting of a streak camera with film readout. The use of fiber optics provides a faster time response than can presently be obtained with equalized coaxial cables over comparable distances. Fibers also have significant cost and physical size advantages over coax cables. The streak camera achieves a much higher information density than an equivalent oscilloscope system, and it also serves as the light detector. The result is a wide bandwidth high capacity system that can be fielded at a relatively low cost in manpower, space, and materials. For this experiment, the streak camera had a 120 ns time window with a 1.2 ns time resolution. Dynamic range for the system was about 1000. Beam current statistical limitations were approximately 8% for a 0.3 ns wide data point at one decade above the threshold recording intensity.

  8. Electron emission from nanostructured materials

    Science.gov (United States)

    Safir, Abdelilah

    In this dissertation, standardized methods for measuring electron emission (EE) from nanostructured materials are established. Design of an emitter array platform, synthesis and nanomanipulation of different types of are successfully conducted. Preexisting as well as novel nanostructures are examined for possible use as electron point sources. Three main categories of emitters are under evaluation: oxide nanowires, metallic nanowires and carbon based nanomaterials (CBNs). Tungsten oxides nanowires have low work function, then metallic nanowires have high electrical conductivity and abundant number of free electrons at and below their Fermi level and lastly, CBNs have superior electrical, mechanical, chemical and thermal properties. This evaluation is designed to compare and choose among the nanoemitters that are suitable for EE. Simulation through theoretical modeling is provided to optimize the parameters directly or indirectly affecting EE properties. The models are to enhance the emitter's performance through increase the packing density, reduce the field screening effect, lower the turn-on and the threshold electric fields and increase the emission current densities. The current estimations and the modeling of the validity regions where EE types theoretically exist, help to select and fabricate optimum emitters. An assembly consisting of sample substrate, electrical feedthroughs, electrodes, nano/micro-manipulator and insulators are mounted within a vacuum chamber. An ion vacuum pump and a turbo pump are used to reach a vacuum pressure of 10-7 Torr. Two systems are used for EE characterization of nanostructures: bulk and In-situ configurations. The bulk investigation is realized by designing a vacuum chamber and different sample holders that can resist harsh environment as well as high temperature for both FE and TE experiments. In-situ experiments are conducted in the chamber of the scanning electron microscope (SEM), it consists of designing special sample

  9. Mechanical energy losses in plastically deformed and electron plus neutron irradiated high purity single crystalline molybdenum at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zelada, Griselda I. [Laboratorio de Materiales, Escuela de Ingenieria Electrica, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Avda. Pellegrini 250, 2000 Rosario (Argentina); Lambri, Osvaldo Agustin [Laboratorio de Materiales, Escuela de Ingenieria Electrica, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Avda. Pellegrini 250, 2000 Rosario (Argentina); Instituto de Fisica Rosario - CONICET, Member of the CONICET& #x27; s Research Staff, Avda. Pellegrini 250, 2000 Rosario (Argentina); Bozzano, Patricia B. [Laboratorio de Microscopia Electronica, Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avda. Gral. Paz 1499, 1650 San Martin (Argentina); Garcia, Jose Angel [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain)

    2012-10-15

    Mechanical spectroscopy (MS) and transmission electron microscopy (TEM) studies have been performed in plastically deformed and electron plus neutron irradiated high purity single crystalline molybdenum, oriented for single slip, in order to study the dislocation dynamics in the temperature range within one third of the melting temperature. A damping peak related to the interaction of dislocation lines with both prismatic loops and tangles of dislocations was found. The peak temperature ranges between 900 and 1050 K, for an oscillating frequency of about 1 Hz. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Immobilization of actinides in stable mineral type and ceramic materials (high temperature synthesis)

    Energy Technology Data Exchange (ETDEWEB)

    Starkov, O.; Konovalov, E.

    1996-05-01

    Alternative vitrification technologies are being developed in the world for the immobilization of high radioactive waste in materials with improved thermodynamic stability, as well as improved chemical and thermal stability and stability to radiation. Oxides, synthesized in the form of analogs to rock-forming minerals and ceramics, are among those materials that have highly stable properties and are compatible with the environment. In choosing the appropriate material, we need to be guided by its geometric stability, the minimal number of cations in the structure of the material and the presence of structural elements in the mineral that are isomorphs of uranium and thorium, actinoids found in nature. Rare earth elements, yttrium, zirconium and calcium are therefore suitable. The minerals listed in the table (with the exception of the zircon) are pegatites by origin, i.e. they are formed towards the end of the magma crystallization of silicates form the residual melt, enriched with Ta, Nb, Ti, Zr, Ce, Y, U and Th. Uranium and thorium in the form of isomorphic admixtures form part of the lattice of the mineral. These minerals, which are rather simple in composition and structure and are formed under high temperatures, may be viewed as natural physio-chemical systems that are stable and long-lived in natural environments. The similarity of the properties of actinoids and lanthanoids plays an important role in the geochemistry of uranium and thorium; however, uranium (IV) is closer to the {open_quotes}heavy{close_quotes} group of lanthanoids (the yttrium group) while thorium (IV) is closer to the {open_quotes}light{close_quotes} group (the cerium group). That is why rare earth minerals contain uranium and thorium in the form of isomorphic admixtures.

  11. Material Control and Accounting Design Considerations for High-Temperature Gas Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Trond Bjornard; John Hockert

    2011-08-01

    The subject of this report is domestic safeguards and security by design (2SBD) for high-temperature gas reactors, focusing on material control and accountability (MC&A). The motivation for the report is to provide 2SBD support to the Next Generation Nuclear Plant (NGNP) project, which was launched by Congress in 2005. This introductory section will provide some background on the NGNP project and an overview of the 2SBD concept. The remaining chapters focus specifically on design aspects of the candidate high-temperature gas reactors (HTGRs) relevant to MC&A, Nuclear Regulatory Commission (NRC) requirements, and proposed MC&A approaches for the two major HTGR reactor types: pebble bed and prismatic. Of the prismatic type, two candidates are under consideration: (1) GA's GT-MHR (Gas Turbine-Modular Helium Reactor), and (2) the Modular High-Temperature Reactor (M-HTR), a derivative of Areva's Antares reactor. The future of the pebble-bed modular reactor (PBMR) for NGNP is uncertain, as the PBMR consortium partners (Westinghouse, PBMR [Pty] and The Shaw Group) were unable to agree on the path forward for NGNP during 2010. However, during the technology assessment of the conceptual design phase (Phase 1) of the NGNP project, AREVA provided design information and technology assessment of their pebble bed fueled plant design called the HTR-Module concept. AREVA does not intend to pursue this design for NGNP, preferring instead a modular reactor based on the prismatic Antares concept. Since MC&A relevant design information is available for both pebble concepts, the pebble-bed HTGRs considered in this report are: (1) Westinghouse PBMR; and (2) AREVA HTR-Module. The DOE Office of Nuclear Energy (DOE-NE) sponsors the Fuel Cycle Research and Development program (FCR&D), which contains an element specifically focused on the domestic (or state) aspects of SBD. This Material Protection, Control and Accountancy Technology (MPACT) program supports the present work

  12. ODS-materials for high temperature applications in advanced nuclear systems

    Directory of Open Access Journals (Sweden)

    C.C. Eiselt

    2016-12-01

    Full Text Available A ferritic ODS-alloy (Fe-14Cr-1W-0.25Ti has been manufactured by application of the powder metallurgical production route involving at first mechanical alloying of ∼10kg pre-alloyed steel powder together with an Y2O3 addition for 12h in a high energy industrial ball mill under hydrogen atmosphere at the company ZOZ GmbH. As a next step, one part of the alloyed powder was hot extruded into rods while another portion was hot isostatically pressed into plates. Both materials were then heat treated. A characterization program on these ODS-alloy production forms included microstructural and mechanical investigations: SANS and TEM assume the existence of Y2Ti2O7 nano clusters and show a bimodal distribution of ODS-particle sizes in both ODS variants. EBSD maps showed a strong 〈110〉 texture corresponding to the α fiber for the hot extruded ODS and a slight 〈001〉 texture for the hipped ODS material. Fracture toughness tests in different specimen orientations (extruded ODS with mini 0.2T C(T specimens together with Charpy impact tests revealed anisotropic mechanical properties: Promising (fracture toughness levels were obtained in the specimen orientation perpendicular to the extrusion direction, while the toughness levels remained low in extrusion direction and generally for the hipped ODS material at all test temperatures. The fracture toughness tests were performed according to ASTM E 1921 and 1820 standards.

  13. Microencapsulation of metal-based phase change material for high-temperature thermal energy storage.

    Science.gov (United States)

    Nomura, Takahiro; Zhu, Chunyu; Sheng, Nan; Saito, Genki; Akiyama, Tomohiro

    2015-03-13

    Latent heat storage using alloys as phase change materials (PCMs) is an attractive option for high-temperature thermal energy storage. Encapsulation of these PCMs is essential for their successful use. However, so far, technology for producing microencapsulated PCMs (MEPCMs) that can be used above 500°C has not been established. Therefore, in this study, we developed Al-Si alloy microsphere MEPCMs covered by α-Al2O3 shells. The MEPCM was prepared in two steps: (1) the formation of an AlOOH shell on the PCM particles using a boehmite treatment, and (2) heat-oxidation treatment in an O2 atmosphere to form a stable α-Al2O3 shell. The MEPCM presented a melting point of 573°C and latent heat of 247 J g(-1). The cycling performance showed good durability. These results indicated the possibility of using MEPCM at high temperatures. The MEPCM developed in this study has great promise in future energy and chemical processes, such as exergy recuperation and process intensification.

  14. High Temperature Materials Laboratory sixth annual report, October 1992--September 1993

    Energy Technology Data Exchange (ETDEWEB)

    Tennery, V.J.; Foust, F.M.

    1993-12-01

    The High Temperature Materials Laboratory has completed its sixth year of operation as a designated Department of Energy User Facility at the Oak Ridge National Laboratory. Growth of the User Program is evidenced by the number of outside institutions executing user agreements since the facility began operation in 1987. A total of 172 nonproprietary agreements (88 university and 84 industry) and 35 proprietary agreements, (2 university, 33 industry) are now in effect. Six other government facilities have also participated in the User Program. Thirty-eight states are represented by these interactions. Ninety-four nonproprietary research proposals (44 from universities, 47 from industry, and 3 from other government facilities) and three proprietary proposals were considered during this reporting period. Nonproprietary research projects active in FY 1993 are summarized.

  15. High Temperature Materials Laboratory fourth annual report, October 1990--September 1991

    Energy Technology Data Exchange (ETDEWEB)

    Tennery, V.J.; Foust, F.M.

    1991-12-01

    The High Temperature Materials Laboratory has completed its fourth year of operation as a designated Department of Energy User Facility at the Oak Ridge National Laboratory. Growth of the user program is evidenced by the number of outside institutions who have executed user agreements since the facility began operation in 1987. A total of 118 nonproprietary agreements (62 university and 56 industry) and 28 proprietary agreements (2 university, 26 industry) are now in effect. Five other government facilities have also participated in the user program. Sixty-free nonproprietary research proposals (38 from university, 26 from industry, and 1 other government facility) and four proprietary proposals were considered during this reporting period. Research projects active in FY 1991 are summarized.

  16. High Temperature Materials Laboratory fifth annual report, October 1991--September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Tennery, V.J.; Foust, F.M.

    1992-12-01

    The High Temperature Materials Laboratory (HTML) has completed its fifth year of operation as a designated Department of Energy (DOE) User Facility at the Oak Ridge National Laboratory (ORNL). Growth of the User Program is evidenced by the number of outside institutions executing user agreements since the facility began operation in 1987. A total of 145 nonproprietary agreements (77 university and 68 industry) and 30 proprietary agreements (2 university, 28 industry) are now in effect. Five other government facilities have also participated in the User Program. Thirty-six states are represented by these interactions. Eighty-one nonproprietary research proposals (44 from university, 36 from industry, and 1 other government facility) and six proprietary proposals were considered during this reporting period. Research projects active in FY 1992 are summarized.

  17. Fire victim identification by post-mortem dental CT: Radiologic evaluation of restorative materials after exposure to high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Woisetschlaeger, Mischa, E-mail: Mischa.woisetschlager@lio.se [Center for Medical Image Science and Visualisation (CMIV), University Hospital Linkoeping, Linkoeping University, 58185 Linkoeping (Sweden); Lussi, Adrian, E-mail: anders.persson@cmiv.lio.se [Department of Preventive, Restorative and Pediatric Dentistry, School of Dental Medicine, University of Bern, Freiburgstrasse 7, 3010 Bern (Switzerland); Persson, Anders, E-mail: adrian.lussi@zmk.unibe.ch [Center for Medical Image Science and Visualisation (CMIV), University Hospital Linkoeping, Linkoeping University, 58185 Linkoeping (Sweden); Jackowski, Christian, E-mail: christian.jackowski@irm.uzh.ch [Center for Medical Image Science and Visualisation (CMIV), University Hospital Linkoeping, Linkoeping University, 58185 Linkoeping (Sweden); Institute of Legal Medicine, University of Zuerich, Winterthurerstrasse 190/52, 8057 Zuerich (Switzerland)

    2011-11-15

    Objectives: The aim of this study was to evaluate the use of high resolution CT to radiologically define teeth filling material properties in terms of Hounsfield units after high temperature exposure. Methods: 122 human molars with 10 different filling materials at defined filling diameters were examined. The teeth were CT scanned both before and after the exposure to different temperatures. After image reconstruction, the teeth and filling materials were analyzed regarding their morphology and Hounsfield units (HU) using an extended HU scale. Results: The majority of filling materials diminished in size at temperatures {>=}400 deg. C. HU values were stable for all materials up till 200 deg. C, and only slightly changed up to 600 deg. C. Cerec, Dyract and dentin showed only minor changes in HU at all temperatures. The other materials, inclusive enamel, showed specific patterns, either increasing or decreasing in HU with increasing temperatures over 600 deg. C. Conclusions: Over 600 deg. C the filling materials show specific patterns that can be used to discriminate filling materials. Ultra high resolution CT may improve the identification processes in fire victims. Existing 3D visualization presets for the dentition can be used until 600 deg. C and have to be optimized for bodies exposed to higher temperatures.

  18. Studies and development of high-temperature catalytic materials for application in gas turbine combustion chamber

    Energy Technology Data Exchange (ETDEWEB)

    Papadias, Dennis; Thevenin, Philippe [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    2000-04-01

    -based garnets and aluminium titanate. The NZP materials (NaZr{sub 2}(PO{sub 4}){sub 3}) have an ultra-low thermal expansion which gives them the desired properties to stand thermal shocks. However their catalytic activity needs to be improved as they have a T{sub 50} above 520 deg C. The iron containing garnets (YIG) with the following formula Y{sub 3}Fe{sub 5}O{sub 12}, as well as the MgAl{sub 2}O{sub 4} spinel, show promising results with an activity close to the hexaaluminates. Different fuels could be considered for application in gas turbine combustion chambers. Ethanol appears to be a promising alternative fuel for mobile gas turbines, methane and gasified biomass for stationary utilisation. The experimental work in this project has been done using ethanol as fuel. The coming work will be oriented towards gasified biomass as well. Specific attention will be given to fuel-NO{sub x} formation from the ammonia present in the feed. The work was carried out in co-operation with Volvo Aero Corporation, which was involved in the European project AGATA where the objective was to develop a ceramic gas turbine for hybrid car applications. Furthermore, another project within catalytic combustion for gas turbine is conducted in co-operation with the Division of Heat and Power Technology at KTH (Nutek project P7057, Catalytic Combustion of Gasified Biomass). In this projects a fully catalytic system has been chosen. However a solution to overcome the problem given by the high temperature present in the last section of the combustor is a hybrid system described in the literature. A first catalyst segment with low temperature catalytic activity ignites part of the fuel at 300-400 deg C. The rest of the fuel is then burned homogeneously between 1000 - 1400 deg C. This design avoid the use of catalytic material at temperature above 1000 deg C. Different projects are running both in the US (Catalytica Combustion Systems Inc., Precision Combustion) and Japan (Osaka Gas Company) to develop a

  19. An electrostatic levitator for high-temperature containerless materials processing in 1-g

    Science.gov (United States)

    Rhim, Won-Kyu; Chung, Sang K.; Barber, Daniel; Man, Kin F.; Gutt, Gary; Rulison, Aaron; Spjut, R. Erik

    1993-10-01

    This article discusses recent developments in high-temperature electrostatic levitation technology for containerless processing of metals and alloys. Presented is the first demonstration of an electrostatic levitation technology which can levitate metals and alloys (2-4 mm diam spheres) in vacuum and of superheating-undercooling-recalescence cycles which can be repeated while maintaining good positioning stability. The electrostatic levitator (ESL) has several important advantages over the electromagnetic levitator. Most important is the wide range of sample temperature which can be achieved without affecting levitation. This article also describes the general architecture of the levitator, electrode design, position control hardware and software, sample heating, charging, and preparation methods, and operational procedures. Particular emphasis is given to sample charging by photoelectric and thermionic emission. While this ESL is more oriented toward ground-based operation, an extension to microgravity applications is also addressed briefly. The system performance was demonstrated by showing multiple superheating-undercooling-recalescence cycles in a zirconium sample (Tm=2128 K). This levitator, when fully matured, will be a valuable tool both in Earth-based and space-based laboratories for the study of thermophysical properties of undercooled liquids, nucleation kinetics, the creation of metastable phases, and access to a wide range of materials with novel properties.

  20. Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability

    DEFF Research Database (Denmark)

    Ashokkumar, Saranya; Adler-Nissen, Jens; Møller, Per

    2012-01-01

    The main aim of the work was to investigate the wettability of different surface materials with vegetable oil (olive oil) over the temperature range of 25–200°C to understand the differences in cleanability of different surfaces exposed to high temperatures in food processes. The different surface...... different levels of roughness. The cosine of the contact angle of olive oil on different surface materials rises linearly with increasing temperature. Among the materials analyzed, polymers (PTFE, silicone) gave the lowest cosθ values. Studies of the effect of roughness and surface flaws on wettability...

  1. High temperature catalyst combustion method and catalyst material; Koonshokubai nenshoho to shokubai zairyo

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, Koichi [Kyushu University, Fukuoka (Japan)

    1999-08-01

    The high temperature catalyst combustion has not yet come to the practical stage. However, the application to gas turbine combustion machine, etc. is expected. The high temperature catalyst combustion has next features further than the combustion reaction of homogeneous system, which generates present flame. (1) The burning rate is big, and the combustion efficiency is also high. Stabilized combustion is obtained, because it not becomes partially a high temperature. (2) Thermal The generation of NOx is dependent on the temperature resistant, and over 1500 degrees C , the speed of the NOx generation consists in the anther. (3) It can be correspondent to air and fuel ratio such as the exhaust gas including thin organic compounds. (4) Since the reaction progresses in the catalyst surface, the surface is maintained in comparison with the gas phase reaction in high temperature. Therefore, the furnace volume can be miniaturized. (5) In case of the adiabatic reactor, heat recovery and energy recovery as a power become possible. (NEDO)

  2. High Temperature Joining and Characterization of Joint Properties in Silicon Carbide-Based Composite Materials

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay

    2015-01-01

    Advanced silicon carbide-based ceramics and composites are being developed for a wide variety of high temperature extreme environment applications. Robust high temperature joining and integration technologies are enabling for the fabrication and manufacturing of large and complex shaped components. The development of a new joining approach called SET (Single-step Elevated Temperature) joining will be described along with the overview of previously developed joining approaches including high temperature brazing, ARCJoinT (Affordable, Robust Ceramic Joining Technology), diffusion bonding, and REABOND (Refractory Eutectic Assisted Bonding). Unlike other approaches, SET joining does not have any lower temperature phases and will therefore have a use temperature above 1315C. Optimization of the composition for full conversion to silicon carbide will be discussed. The goal is to find a composition with no remaining carbon or free silicon. Green tape interlayers were developed for joining. Microstructural analysis and preliminary mechanical tests of the joints will be presented.

  3. High-Temperature Release of SO2 from Calcined Cement Raw Materials

    DEFF Research Database (Denmark)

    Nielsen, Anders Rooma; Larsen, Morten B.; Glarborg, Peter

    2011-01-01

    During combustion of alternative fuels in the material inlet end of cement rotary kilns, local reducing conditions may occur and cause reductive decomposition of sulfates from calcined cement raw materials. Decomposition of sulfates is problematic because it increases the gas-phase SO2...... concentration, which may cause deposit formation in the kiln system. In this study, the release of sulfur from calcined cement raw materials under both oxidizing and reducing conditions is investigated. The investigations include thermodynamic equilibrium calculations in the temperature interval of 800–1500 °C...... and experiments in a tube furnace reactor in the temperature interval of 900–1100 °C. The investigated conditions resemble actual conditions in the material inlet end of cement rotary kilns. It was found that the sulfates CaSO4, K2SO4, and Na2SO4 were all stable under oxidizing conditions but began to decompose...

  4. High-speed measurement of single-electron circuits at low temperatures with bolometric and calorimetric applications

    Science.gov (United States)

    Swenson, Loren

    2007-12-01

    This thesis consists primarily of the description of two single-electron circuits that I fabricated and measured utilizing radio-frequency techniques. A short summary of the background material necessary for understanding this area of condensed matter experiment is included as well as a discussion of the utility of these devices as charge-sensing or energy-sensing circuit elements. In the first measurement, by configuring a radio-frequency single-electron transistor as a mixer, we demonstrate a unique implementation of this device, that achieves good charge sensitivity with large bandwidth about a tunable center frequency. In our implementation we achieve a measurement bandwidth of 16 MHz, with a tunable center frequency from 0 to 1.2 GHz, demonstrated with the transistor operating at 300 mK. Ultimately this device is limited in center frequency by the RC time of the transistor's center island, which for our device is ˜1.6 GHz, close to the measured value. The measurement bandwidth is determined by the quality factor of the readout tank circuit. In the second measurement, we detect the energy-selective diffusion of electrons through a tunnel junction to perform a new type of passive, low-power dissipation thermometry. The thermometer is based on a novel, three-junction single electron transistor, which is made with a superconducting nanoscale metal island, coupled to two tunnel junctions and a capacitive gate in the standard single-electron transistor configuration, and in addition a third tunnel junction couples the transistor island to a normal metal thin-film volume, which serves as a calorimeter. Passive diffusion of electrons from the calorimeter through the third junction changes the transistor conductance, providing a thermometric signal. This device dissipates minimal power in the calorimeter, removing a stringent limit on the minimum temperatures and energy sensitivities achievable in nanoscale calorimeters and bolometers. High speed measurements were

  5. Materials corrosion of high temperature alloys immersed in 600C binary nitrate salt.

    Energy Technology Data Exchange (ETDEWEB)

    Kruizenga, Alan Michael; Gill, David Dennis; LaFord, Marianne Elizabeth

    2013-03-01

    Thirteen high temperature alloys were immersion tested in a 60/40 binary nitrate salt. Samples were interval tested up to 3000 hours at 600ÀC with air as the ullage gas. Chemical analysis of the molten salt indicated lower nitrite concentrations present in the salt, as predicted by the equilibrium equation. Corrosion rates were generally low for all alloys. Corrosion products were identified using x-ray diffraction and electron microprobe analysis. Fe-Cr based alloys tended to form mixtures of sodium and iron oxides, while Fe-Ni/Cr alloys had similar corrosion products plus oxides of nickel and chromium. Nickel based alloys primarily formed NiO, with chromium oxides near the oxide/base alloy interface. In625 exhibited similar corrosion performance in relation to previous tests, lending confidence in comparisons between past and present experiments. HA230 exhibited internal oxidation that consisted of a nickel/chromium oxide. Alloys with significant aluminum alloying tended to exhibit superior performance, due formation of a thin alumina layer. Soluble corrosion products of chromium, molybdenum, and tungsten were also formed and are thought to be a significant factor in alloy performance.

  6. Accurate electronic free energies of the 3 d ,4 d , and 5 d transition metals at high temperatures

    Science.gov (United States)

    Zhang, Xi; Grabowski, Blazej; Körmann, Fritz; Freysoldt, Christoph; Neugebauer, Jörg

    2017-04-01

    Free energies of bulk materials are nowadays routinely computed by density functional theory. In particular for metals, electronic excitations can significantly contribute to the free energy. For an ideal static lattice, this contribution can be obtained at low computational cost, e.g., from the electronic density of states derived at T =0 K or by utilizing the Sommerfeld approximation. The error introduced by these approximations at elevated temperatures is rarely known. The error arising from the ideal lattice approximation is likewise unexplored but computationally much more challenging to overcome. In order to shed light on these issues we have computed the electronic free energies for all 3 d ,4 d , and 5 d transition elements on the ideal lattices of the bcc, fcc, and hcp structures using finite-temperature density-functional theory. For a subset of elements we have explored the impact of explicit thermal vibrations on the electronic free energies by using ab initio molecular dynamics simulations. We provide an analysis of the observed chemical trends in terms of the electronic density of states and the canonical d band model and quantify the errors in the approximate methods. The electronic contribution to the heat capacities and the corresponding errors due to the different approximations are studied as well.

  7. Fly ash porous material using geopolymerization process for high temperature exposure.

    Science.gov (United States)

    Abdullah, Mohd Mustafa Al Bakri; Jamaludin, Liyana; Hussin, Kamarudin; Bnhussain, Mohamed; Ghazali, Che Mohd Ruzaidi; Ahmad, Mohd Izzat

    2012-01-01

    This paper presents the results of a study on the effect of temperature on geopolymers manufactured using pozzolanic materials (fly ash). In this paper, we report on our investigation of the performance of porous geopolymers made with fly ash after exposure to temperatures from 600 °C up to 1000 °C. The research methodology consisted of pozzolanic materials (fly ash) synthesized with a mixture of sodium hydroxide and sodium silicate solution as an alkaline activator. Foaming agent solution was added to geopolymer paste. The geopolymer paste samples were cured at 60 °C for one day and the geopolymers samples were sintered from 600 °C to 1000 °C to evaluate strength loss due to thermal damage. We also studied their phase formation and microstructure. The heated geopolymers samples were tested by compressive strength after three days. The results showed that the porous geopolymers exhibited strength increases after temperature exposure.

  8. Fly Ash Porous Material using Geopolymerization Process for High Temperature Exposure

    Directory of Open Access Journals (Sweden)

    Mohd Izzat Ahmad

    2012-04-01

    Full Text Available This paper presents the results of a study on the effect of temperature on geopolymers manufactured using pozzolanic materials (fly ash. In this paper, we report on our investigation of the performance of porous geopolymers made with fly ash after exposure to temperatures from 600 °C up to 1000 °C. The research methodology consisted of pozzolanic materials (fly ash synthesized with a mixture of sodium hydroxide and sodium silicate solution as an alkaline activator. Foaming agent solution was added to geopolymer paste. The geopolymer paste samples were cured at 60 °C for one day and the geopolymers samples were sintered from 600 °C to 1000 °C to evaluate strength loss due to thermal damage. We also studied their phase formation and microstructure. The heated geopolymers samples were tested by compressive strength after three days. The results showed that the porous geopolymers exhibited strength increases after temperature exposure.

  9. Primary defect transformations in high-resistivity p-type silicon irradiated with electrons at cryogenic temperatures

    CERN Document Server

    Makarenko, L F; Korshunov, F P; Murin, L I; Moll, M

    2009-01-01

    It has been revealed that self-interstitials formed under low intensity electron irradiationin high resistivity p-type silicon can be retained frozen up to room temperature. Low thermal mobility of the self-interstitials suggests that Frenkelpair sinsilicon can be stable at temperatures of about or higher than 100K. A broad DLTS peak with activation energy of 0.14–0.17eV can be identified as related to Frenkel pairs. This peak anneals out at temperatures of 120 140K. Experimental evidences are presented that be coming more mobile under forwardcurrent injection the self-interstitials change their charge state to a less positive one.

  10. Experimental Evaluation and Comparison of Thermal Conductivity of High-Voltage Insulation Materials for Vacuum Electronic Devices

    Science.gov (United States)

    Suresh, C.; Srikrishna, P.

    2017-07-01

    Vacuum electronic devices operate with very high voltage differences between their sub-assemblies which are separated by very small distances. These devices also emit large amounts of heat that needs to be dissipated. Hence, there exists a requirement for high-voltage insulators with good thermal conductivity for voltage isolation and efficient heat dissipation. However, these voltage insulators are generally poor conductors of heat. In the present work, an effort has been made to obtain good high-voltage insulation materials with substantial improvement in their thermal conductivity. New mixtures of composites were formed by blending varying percentages (by volumes) of aluminum nitride powders with that of neat room-temperature vulcanizing (RTV) silicone elastomer compound. In this work, a thermal conductivity test setup has been devised for the quantification of the thermal conductivity of the insulators. The thermal conductivities and high-voltage isolation capabilities of various blended composites were quantified and were compared with that of neat RTV to evaluate the relative improvement.

  11. Feasibility Studies of the Two Filters Method in TJ-II for Electron Temperature Measurements in High Density Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Baiao, D.; Medina, F.; Ochando, M.; Varandas, C.

    2009-07-01

    The TJ-II plasma soft X-ray emission was studied in order to establish an adequate setup for an electron temperature diagnostic suitable for high density, with spatial and temporal resolutions, based on the two-filters method. The preliminary experimental results reported were obtained with two diagnostics (an X-ray PHA based on a Ge detector and a tomography system) already installed in TJ-II stellarator. These results lead to the conclusion that the two-filters method was a suitable option for an electron temperature diagnostic for high-density plasmas in TJ-II. We present the design and fi rst results obtained with a prototype for the measurement of electron temperature in TJ-II plasmas heated with energetic neutral beams. This system consists in two AXUV20A detectors which measure the soft X-ray plasma emissivity trough beryllium filters of different thickness. From the two-filters technique it is possible to estimate the electron temperature. The analyses carried out allowed concluding which filter thicknesses are most suited for TJ-II plasmas, and enhanced the need of a computer code to simulate signals and plasma compositions. (Author) 7 refs.

  12. Novel Methods of Tritium Sequestration: High Temperature Gettering and Separation Membrane Materials Discovery for Nuclear Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Franglin [Univ. of South Carolina, Columbia, SC (United States); Sholl, David [Georgia Inst. of Technology, Atlanta, GA (United States); Brinkman, Kyle [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Lyer, Ratnasabapathy [Claflin Univ., Orangeburg, SC (United States); Iyer, Ratnasabapathy [Claflin Univ., Orangeburg, SC (United States); Reifsnider, Kenneth [Univ. of South Carolina, Columbia, SC (United States)

    2015-01-22

    This project is aimed at addressing critical issues related to tritium sequestration in next generation nuclear energy systems. A technical hurdle to the use of high temperature heat from the exhaust produced in the next generation nuclear processes in commercial applications such as nuclear hydrogen production is the trace level of tritium present in the exhaust gas streams. This presents a significant challenge since the removal of tritium from the high temperature gas stream must be accomplished at elevated temperatures in order to subsequently make use of this heat in downstream processing. One aspect of the current project is to extend the techniques and knowledge base for metal hydride materials being developed for the ''hydrogen economy'' based on low temperature absorption/desorption of hydrogen to develop materials with adequate thermal stability and an affinity for hydrogen at elevated temperatures. The second focus area of this project is to evaluate high temperature proton conducting materials as hydrogen isotope separation membranes. Both computational and experimental approaches will be applied to enhance the knowledge base of hydrogen interactions with metal and metal oxide materials. The common theme between both branches of research is the emphasis on both composition and microstructure influence on the performance of sequestration materials.

  13. The Influence of Electron Temperature and Magnetic Field Strength on Cosmic-Ray Injection in High Mach Number Shocks

    Science.gov (United States)

    Schmitz, H.; Chapman, S. C.; Dendy, R. O.

    2002-05-01

    Electron preacceleration from thermal to mildly relativistic energies in high Mach number shocks (the injection problem) is an outstanding issue in understanding synchrotron radiation from supernova remnants. At high Alfvénic Mach numbers, collisionless perpendicular shocks reflect a fraction of the upstream ions. This gives rise to two-stream instabilities, which in turn can accelerate ions. However, in astrophysical plasmas, the value of β-the ratio of kinetic pressure to magnetic pressure-is not well known. We have used a particle in cell simulation code to investigate the influence of β on the shock structure and on the electron acceleration (assuming thermodynamic equilibrium in the undisturbed plasma, β=βi=βe). Previous simulations at low values of β showed that the phase space distributions of electrons and ions became highly structured: characteristic holes appear in the electron phase space, and the shock dynamics exhibit reformation processes. However, we find that all these features disappear at higher β due to the high initial thermal velocity of the electrons. It follows that the electron cosmic-ray injection mechanism depends strongly on β, that is, on the electron temperature normalized to the magnetic field upstream.

  14. High Temperature Materials Laboratory seventh annual report, October 1993--September 1994

    Energy Technology Data Exchange (ETDEWEB)

    Tennery, V.J.; Teague, P.A.

    1994-12-01

    The High Temperature Materials Laboratory (HTML) has completed its seventh year of operation as a designated Department of Energy User Facility at the Oak Ridge National Laboratory. Growth of the User Program has been demonstrated by the number of institutions executing user agreements since the HTML began operation in 1987. A total of 193 nonproprietary agreements (91 industry and 102 university) and 41 proprietary agreements (39 industry and two university) are now in effect. This represents an increase of 21 nonproprietary user agreements during FY 1994. Forty-one states are represented by these users. During FY 1994, the HTML User Program evaluated 106 nonproprietary proposals (46 from industry, 52 from universities, and 8 from other government facilities) and 8 proprietary proposals. The HTML User Advisory Committee approved about ninety-five percent of those evaluated proposals, sometimes after the prospective user revised the proposal based on comments from the Committee. This annual report discusses FY 1994 activities in the individual user centers, as well as plans for the future. It also gives statistics about users and their proposals and FY 1994 publications, and summarizes nonproprietary research projects active in FY 1994.

  15. High Temperature Materials Laboratory eight and ninth annual reports, October 1994 through September 1996

    Energy Technology Data Exchange (ETDEWEB)

    Pasto, A.E.; Russell, B.J.

    1997-10-01

    The High Temperature Materials Laboratory (HTML) has completed its ninth year of operation as a designated US Department of Energy User Facility at the Oak Ridge National Laboratory. This document profiles the historical growth of the HTML User and Fellowship Programs since their inception in 1987. Growth of the HTML programs has been demonstrated by the number of institutions executing user agreements, and by the number of days of instrument use (user days) since the HTML began operation. A total of 276 nonproprietary agreements (135 industry, 135 university, and 6 other federal agency) and 56 proprietary agreements are now in effect. This represents an increase of 70 nonproprietary user agreements since the last reporting period (for FY 1994). A state-by-state summary of these nonproprietary user agreements is given in Appendix A, and an alphabetical listing is provided in Appendix B. Forty-four states are represented by these users. During FY 1995 and 1996, the HTML User Program evaluated 145 nonproprietary proposals (62 from industry, 82 from universities, and 1 from other government facilities) and several proprietary proposals. The HTML User Advisory Committee approved about 95% of those proposals, frequently after the prospective user revised the proposal based on comments from the committee. This annual report discusses activities in the individual user centers, as well as plans for the future. It also gives statistics about users, proposals, and publications as well as summaries of the nonproprietary research projects active during 1995 and 1996.

  16. High Temperature Materials Laboratory, Eleventh Annual Report: October 1997 through September 1998

    Energy Technology Data Exchange (ETDEWEB)

    Pasto, A.E.; Russell, B.J.

    2000-03-01

    The High Temperature Materials Laboratory (HTML) has completed its eleventh year of operation as a designated US Department of Energy User Facility at the Oak Ridge National Laboratory. This document profiles the historical growth of the HTML User and Fellowship Programs since their inception in 1987. Growth of the HTML programs has been demonstrated by the number of institutions executing user agreements and by the number of days of instrument use (user days) since the HTML began operation.A total of 522 agreements (351 industry,156 university,and 15 other federal agency) are now in effect (452 nonproprietary and 70 proprietary). This represents an increase of 75 user agreements since the last reporting period (for FY 1997). A state-by-state summary of the nonproprietary user agreements is given in Appendix A. Forty-six states are represented. During FY 1998, the HTML User Program evaluated 80 nonproprietary proposals (32 from industry, 45 from universities, and 3 from other government facilities) and several proprietary proposals. Appendix B provides a detailed breakdown of the nonproprietary proposals received during FY 1998. The HTML User Advisory Committee approved about 95% of those proposals, sometimes after the prospective user revised the proposal based on comments from the committee. This annual report discusses activities in the individual user centers as well as plans for the future. It also gives statistics about users, proposals, and publications as well as summaries of the nonproprietary research projects active during 1998.

  17. High-temperature optically activated GaAs power switching for aircraft digital electronic control

    Science.gov (United States)

    Berak, J. M.; Grantham, D. H.; Swindal, J. L.; Black, J. F.; Allen, L. B.

    1983-01-01

    Gallium arsenide high-temperature devices were fabricated and assembled into an optically activated pulse-width-modulated power control for a torque motor typical of the kinds used in jet engine actuators. A bipolar heterojunction phototransistor with gallium aluminum arsenide emitter/window, a gallium arsenide junction field-effect power transistor and a gallium arsenide transient protection diode were designed and fabricated. A high-temperature fiber optic/phototransistor coupling scheme was implemented. The devices assembled into the demonstrator were successfully tested at 250 C, proving the feasibility of actuator-located switching of control power using optical signals transmitted by fibers. Assessments of the efficiency and technical merits were made for extension of this high-temperature technology to local conversion of optical power to electrical power and its control at levels useful for driving actuators. Optical power sources included in the comparisons were an infrared light-emitting diode, an injection laser diode, tungsten-halogen lamps and arc lamps. Optical-to-electrical power conversion was limited to photovoltaics located at the actuator. Impedance matching of the photovoltaic array to the load was considered over the full temperature range, -55 C to 260 C. Loss of photovoltaic efficiency at higher temperatures was taken into account. Serious losses in efficiency are: (1) in the optical source and the cooling which they may require in the assumed 125 C ambient, (2) in the decreased conversion efficiency of the gallium arsenide photovoltaic at 260 C, and (3) in impedance matching. Practical systems require improvements in these areas.

  18. Materials for the very high temperature reactor (VHTR): a versatile nuclear power station for combined cycle electricity and heat production

    Energy Technology Data Exchange (ETDEWEB)

    Hoffelner, W

    2005-07-01

    The International Generation IV Initiative provides a research platform for the development of advanced nuclear plants which are able to produce electricity and heat in a combined cycle. Very high-temperature gas-cooled reactors are considered as near-term deployable plants meeting these requirements. They build on high-temperature gas-cooled reactors which are already in operation. The main parts of such an advanced plant are: reactor pressure vessel, core and close-to-core components, gas turbine, intermediate heat exchanger, and hydrogen production unit. The paper discusses the VHTR concept, materials, fuel and hydrogen production based on discussions on research and development projects addressed within the generation IV community. It is shown that material limitations might restrict the outlet temperature of near-term deployable VHTRs to about 950 {sup o}C. The impact of the high temperatures on fuel development is also discussed. Current status of combined cycle hydrogen production is elaborated on. (author)

  19. O3 Layers via Spray Pyrolysis at Low Temperatures and Their Application in High Electron Mobility Transistors

    KAUST Repository

    Isakov, Ivan

    2017-04-06

    The growth mechanism of indium oxide (InO) layers processed via spray pyrolysis of an aqueous precursor solution in the temperature range of 100-300 °C and the impact on their electron transporting properties are studied. Analysis of the droplet impingement sites on the substrate\\'s surface as a function of its temperature reveals that Leidenfrost effect dominated boiling plays a crucial role in the growth of smooth, continuous, and highly crystalline InO layers via a vapor phase-like process. By careful optimization of the precursor formulation, deposition conditions, and choice of substrate, this effect is exploited and ultrathin and exceptionally smooth layers of InO are grown over large area substrates at temperatures as low as 252 °C. Thin-film transistors (TFTs) fabricated using these optimized InO layers exhibit superior electron transport characteristics with the electron mobility reaching up to 40 cm V s, a value amongst the highest reported to date for solution-processed InO TFTs. The present work contributes enormously to the basic understanding of spray pyrolysis and highlights its tremendous potential for large-volume manufacturing of high-performance metal oxide thin-film transistor electronics.

  20. Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

    KAUST Repository

    Mahmood, Khalid

    2015-03-23

    A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

  1. Thermally Stable Ohmic Contacts on Silicon Carbide Developed for High- Temperature Sensors and Electronics

    Science.gov (United States)

    Okojie, Robert S.

    2001-01-01

    The NASA aerospace program, in particular, requires breakthrough instrumentation inside the combustion chambers of engines for the purpose of, among other things, improving computational fluid dynamics code validation and active engine behavioral control (combustion, flow, stall, and noise). This environment can be as high as 600 degrees Celsius, which is beyond the capability of silicon and gallium arsenide devices. Silicon-carbide- (SiC-) based devices appear to be the most technologically mature among wide-bandgap semiconductors with the proven capability to function at temperatures above 500 degrees Celsius. However, the contact metalization of SiC degrades severely beyond this temperature because of factors such as the interdiffusion between layers, oxidation of the contact, and compositional and microstructural changes at the metal/semiconductor interface. These mechanisms have been proven to be device killers. Very costly and weight-adding packaging schemes that include vacuum sealing are sometimes adopted as a solution.

  2. High temperature corrosion of advanced ceramic materials for hot-gas filters and heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Kupp, E.R.; Trubelja, M.F.; Spear, K.E.; Tressler, R.E. [Pennsylvania State Univ., University Park, PA (United States)

    1995-08-01

    Experimental corrosion studies of hot gas filter materials and heat exchanger materials in oxidizing combustion environments have been initiated. Filter materials from 3M Co. and DuPont Lanxide Composites Inc. are being tested over a range of temperatures, times and gas flows. It has been demonstrated that morphological and phase changes due to corrosive effects occur after exposure of the 3M material to a combustion environment for as little as 25 hours at 800{degrees}C. The study of heat exchanger materials has focused on enhancing the corrosion resistance of DuPont Lanxide Dimox{trademark} composite tubes by adding chromium to its surfaces by (1) heat treatments in a Cr{sub 2}O{sub 3} powder bed, or (2) infiltrating surface porosity with molten chromium nitrate. Each process is followed by a surface homogenization at 1500{degrees}C. The powder bed method has been most successful, producing continuous Cr-rich layers with thicknesses ranging from 20 to 250 {mu}m. As-received and Cr-modified DuPont Lanxide Dimox{trademark} samples will be reacted with commonly encountered coal-ash slags to determine the Cr effects on corrosion resistance.

  3. High temperature structural silicides

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.

    1997-03-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

  4. Effect of ultra high temperature ceramics as fuel cladding materials on the nuclear reactor performance by SERPENT Monte Carlo code

    Energy Technology Data Exchange (ETDEWEB)

    Korkut, Turgay; Kara, Ayhan; Korkut, Hatun [Sinop Univ. (Turkey). Dept. of Nuclear Energy Engineering

    2016-12-15

    Ultra High Temperature Ceramics (UHTCs) have low density and high melting point. So they are useful materials in the nuclear industry especially reactor core design. Three UHTCs (silicon carbide, vanadium carbide, and zirconium carbide) were evaluated as the nuclear fuel cladding materials. The SERPENT Monte Carlo code was used to model CANDU, PWR, and VVER type reactor core and to calculate burnup parameters. Some changes were observed at the same burnup and neutronic parameters (keff, neutron flux, absorption rate, and fission rate, depletion of U-238, U-238, Xe-135, Sm-149) with the use of these UHTCs. Results were compared to conventional cladding material zircalloy.

  5. Materials and Process Design for High-Temperature Carburizing: Integrating Processing and Performance

    Energy Technology Data Exchange (ETDEWEB)

    D. Apelian

    2007-07-23

    The objective of the project is to develop an integrated process for fast, high-temperature carburizing. The new process results in an order of magnitude reduction in cycle time compared to conventional carburizing and represents significant energy savings in addition to a corresponding reduction of scrap associated with distortion free carburizing steels.

  6. Electron spin resonance spectroscopy of high purity crystals at millikelvin temperatures

    Science.gov (United States)

    Farr, Warrick G.; Creedon, Daniel L.; Goryachev, Maxim; Benmessai, Karim; Tobar, Michael E.

    2013-12-01

    Progress in the emerging field of engineered quantum systems requires the development of devices that can act as quantum memories. The realisation of such devices by doping solid state cavities with paramagnetic ions imposes a trade-off between ion concentration and cavity coherence time. Here, we investigate an alternative approach involving interactions between photons and naturally occurring impurity ions in ultra-pure crystalline microwave cavities exhibiting exceptionally high quality factors. We implement a hybrid Whispering Gallery/Electron Spin Resonance method to perform rigorous spectroscopy of an undoped single-crystal sapphire resonator over the frequency range 8{19 GHz, and at external applied DC magnetic fields up to 0.9 T. Measurements of a high purity sapphire cooled close to 100 mK reveal the presence of Fe3+, Cr3+, and V2+ impurities. A host of electron transitions are measured and identified, including the two-photon classically forbidden quadrupole transition (Δms = 2) for Fe3+, as well as hyperfine transitions of V2+.

  7. Pinched propagation of high-power, pulsed electron beams for welding and materials processing applications

    Science.gov (United States)

    Fernsler, Richard F.; Hubbard, Richard F.; Lampe, Martin

    1994-01-01

    Electron beams are used commercially as intense heating sources for welding and related materials processing applications. The beams used for welding operate continuously with energy up to 200 keV and current approximately 1 A. Because these beams are severely degraded by propagation in air over any substantial range, most present-day electron-beam welders require vacuum pumping and precision focusing, which has severely restricted utilization of the technology. Over the past few decades, a different class of electron-beam generators has been developed that produces pulsed beams with energies of several MeV, currents of 1 kA or more, radii as small as 1 mm, pulse lengths of tens of ns, and pulse repetition rates up to several kHz. We show here that beams of this type can propagate in ambient air, in a tightly pinched mode and with acceptable stability, over distances of a few tens of cm. We determine the constraints on the choice of beam parameters, due mainly to the effects of gas scattering and the resistive instability. We show that stability can be enhanced, and the acceptable parameter range extended considerably, by using a narrow conducting pipe filled with air or another gas to guide the beam to the workpiece.

  8. Sol-gel synthesis of carbon based materials reinforced ultra high temperature ceramic composites

    OpenAIRE

    Wang, Xiaojing

    2017-01-01

    This Ph.D. research is based on the development of novel sol-gel techniques for synthesis of nanostructured ultra high temperature ceramics (UHTCs) and subsequent spark plasma sintering (SPS) for densifying the UHTC composites. The liquid nature of the sol-gel process offers advantages such as high purity and ability for mixing and infiltration, and thus it can overcome some shortcomings of the conventional power processing of ceramics. SPS delivers microstructures with good density and fine ...

  9. Circuit for Communication over DC Power Line Using High Temperature Electronics

    Science.gov (United States)

    Krasowski, Michael J. (Inventor); Prokop, Norman F. (Inventor)

    2014-01-01

    A high temperature communications circuit includes a power conductor for concurrently conducting electrical energy for powering circuit components and transmitting a modulated data signal, and a demodulator for demodulating the data signal and generating a serial bit stream based on the data signal. The demodulator includes an absolute value amplifier for conditionally inverting or conditionally passing a signal applied to the absolute value amplifier. The absolute value amplifier utilizes no diodes to control the conditional inversion or passing of the signal applied to the absolute value amplifier.

  10. Microstructure Based Material-Sand Particulate Interactions and Assessment of Coatings for High Temperature Turbine Blades

    Science.gov (United States)

    Murugan, Muthuvel; Ghoshal, Anindya; Walock, Michael; Nieto, Andy; Bravo, Luis; Barnett, Blake; Pepi, Marc; Swab, Jeffrey; Pegg, Robert Tyler; Rowe, Chris; hide

    2017-01-01

    Gas turbine engines for military/commercial fixed-wing and rotary wing aircraft use thermal barrier coatings in the high-temperature sections of the engine for improved efficiency and power. The desire to further make improvements in gas turbine engine efficiency and high power-density is driving the research and development of thermal barrier coatings and the effort of improving their tolerance to fine foreign particulates that may be contained in the intake air. Both commercial and military aircraft engines often are required to operate over sandy regions such as in the Middle-East nations, as well as over volcanic zones. For rotorcraft gas turbine engines, the sand ingestion is adverse during take-off, hovering near ground, and landing conditions. Although, most of the rotorcraft gas turbine engines are fitted with inlet particle separators, they are not 100 percent efficient in filtering fine sand particles of size 75 microns or below. The presence of these fine solid particles in the working fluid medium has an adverse effect on the durability of turbine blade thermal barrier coatings and overall performance of the engine. Typical turbine blade damages include blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The objective of this research is to understand the fine particle interactions with typical ceramic coatings of turbine blades at the microstructure level. A finite-element based microstructure modeling and analysis has been performed to investigate particle-surface interactions, and restitution characteristics. Experimentally, a set of tailored thermal barrier coatings and surface treatments were down-selected through hot burner rig tests and then applied to first stage nozzle vanes of the Gas Generator Turbine of a typical rotorcraft gas turbine engine. Laser Doppler velocity measurements were performed

  11. Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability

    Energy Technology Data Exchange (ETDEWEB)

    Ashokkumar, Saranya, E-mail: saras@food.dtu.dk [Accoat A/S, Munkegardsvej 16, 3490 Kvistgard (Denmark); Food Production Engineering, DTU FOOD, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark); Adler-Nissen, Jens [Food Production Engineering, DTU FOOD, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark); Moller, Per [Department of Materials Science and Engineering, DTU Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark)

    2012-12-15

    Graphical abstract: Plot of cos {theta} versus temperature for metal and ceramic surfaces where cos {theta} rises linearly with increase in temperature. Highlights: Black-Right-Pointing-Pointer cos {theta} of olive oil on different surface materials rises linearly with increase in temperature. Black-Right-Pointing-Pointer Slopes are much higher for quasicrystalline and polymers than for ceramics. Black-Right-Pointing-Pointer Increase in surface roughness and surface flaws increases surface wettability. Black-Right-Pointing-Pointer Contact angle values gave information for grouping easy-clean polymers from other materials. Black-Right-Pointing-Pointer Contact angle measurements cannot directly estimate the cleanability of a surface. - Abstract: The main aim of the work was to investigate the wettability of different surface materials with vegetable oil (olive oil) over the temperature range of 25-200 Degree-Sign C to understand the differences in cleanability of different surfaces exposed to high temperatures in food processes. The different surface materials investigated include stainless steel (reference), PTFE (polytetrafluoroethylene), silicone, quasicrystalline (Al, Fe, Cr) and ceramic coatings: zirconium oxide (ZrO{sub 2}), zirconium nitride (ZrN) and titanium aluminum nitride (TiAlN). The ceramic coatings were deposited on stainless steel with two different levels of roughness. The cosine of the contact angle of olive oil on different surface materials rises linearly with increasing temperature. Among the materials analyzed, polymers (PTFE, silicone) gave the lowest cos {theta} values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos {theta} values increases with increasing roughness and surface flaws. Correlation analysis indicates that the measured contact angle values gave useful information for grouping easy-clean polymer materials from the other materials; for the latter group, there is no direct relation between

  12. High temperature thermoelectric energy conversion

    Science.gov (United States)

    Wood, Charles

    1987-01-01

    The theory and current status of materials research for high-temperature thermoelectric energy conversion are reviewed. Semiconductors are shown to be the preferred class of materials for this application. Optimization of the figure of merit of both broadband and narrow-band semiconductors is discussed as a function of temperature. Phonon scattering mechanisms are discussed, and basic material guidelines are given for reduction of thermal conductivity. Two general classes of materials show promise for high temperature figure of merit (Z) values, namely the rare earth chalcogenides and the boron-rich borides. The electronic transport properties of the rare earth chalcogenides are explicable on the basis of degenerate or partially degenerate n-type semiconductors. Boron and boron-rich borides exhibit p-type hopping conductivity, with detailed explanations proposed for the transport differing from compound to compound. Some discussion is presented on the reasons for the low thermal conductivities in these materials. Also, ZTs greater than one appear to have been realized at high temperature in many of these compounds.

  13. Manufacturing Demonstration Facility: Low Temperature Materials Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graham, David E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moon, Ji-Won [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Datskos, Panos G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gresback, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Ilia N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jacobs, Christopher B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jellison, Gerald Earle [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jang, Gyoung Gug [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Joshi, Pooran C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jung, Hyunsung [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Phelps, Tommy [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-30

    The Manufacturing Demonstration Facility (MDF) low temperature materials synthesis project was established to demonstrate a scalable and sustainable process to produce nanoparticles (NPs) for advanced manufacturing. Previous methods to chemically synthesize NPs typically required expensive, high-purity inorganic chemical reagents, organic solvents and high temperatures. These processes were typically applied at small laboratory scales at yields sufficient for NP characterization, but insufficient to support roll-to-roll processing efforts or device fabrication. The new NanoFermentation processes described here operated at a low temperature (~60 C) in low-cost, aqueous media using bacteria that produce extracellular NPs with controlled size and elemental stoichiometry. Up-scaling activities successfully demonstrated high NP yields and quality in a 900-L pilot-scale reactor, establishing this NanoFermentation process as a competitive biomanufacturing strategy to produce NPs for advanced manufacturing of power electronics, solid-state lighting and sensors.

  14. A report on the possible benefits of using high-temperature superconductor materials in particle accelerator design

    Science.gov (United States)

    Cohen, Leslie; Collins, Robert; Balko, Bohdan

    1988-12-01

    This report discusses different design concepts for particle beam accelerators. It demonstrates that with the use of high temperature superconducting materials, a more compact, lighter, and more robust accelerator design can be realized for the space based Neutral Particle Beam (NPB) accelerator.

  15. High temperature electron beam ion source for the production of single charge ions of most elements of the Periodic Table

    CERN Document Server

    Panteleev, V N; Barzakh, A E; Fedorov, D V; Ivanov, V S; Moroz, F V; Orlov, S Y; Seliverstov, D M; Stroe, L; Tecchio, L B; Volkov, Y M

    2003-01-01

    A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 deg. C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1-6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

  16. High-temperature superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2010-01-01

    The present book aims at describing the phenomenon of superconductivity and high-temperature superconductors discovered by Bednorz and Muller in 1986. The book covers the superconductivity phenomenon, structure of high-Tc superconductors, critical currents, synthesis routes for high Tc materials, superconductivity in cuprates, the proximity effect and SQUIDs, theories of superconductivity and applications of superconductors.

  17. Thermal insulation at high temperatures - possibilities for microporous construction materials; Waermedaemmung bei hohen Temperaturen - Moeglichkeiten mikroporoeser Baustoffe

    Energy Technology Data Exchange (ETDEWEB)

    Schulle, W.; Melzer, D. [TU Bergakademie Freiberg (Germany). Inst. fuer Silikattechnik

    1999-01-19

    The heat transfer of porous high-temperature materials is governed primarily by internal thermal conduction and internal thermal radiation which, for their part, depend on the porosity of the insulating material and its service temperature. A special technique - controlled hydrothermal synthesis - allows the manufacture of microporous heat-insulating materials that are also suitable for service temperatures of well over 1000 C. (orig.) [Deutsch] Der Waermetransport poroeser Hochtemperaturwerkstoffe wird vor allem durch innere Waermeleitung und innere Waermestrahlung bestimmt, die ihrerseits von der Porositaet des Daemmstoffes und seiner Einsatztemperatur abhaengen. Durch ein spezielles Verfahren - die gezielte Hydrothermalsynthese - koennen mikroporoese Waermedaemmstoffe hergestellt werden, die auch fuer Einstztemperaturen von weit ueber 1 000 C geeignet sind. (orig.)

  18. Thermal-Mechanical and Thermal Behavior of High-Temperature Structural Materials.

    Science.gov (United States)

    1979-12-31

    Physical Constants of Porcelain ," Nagoya Kogyo Gijutsu Shikensko Hokoku, 8 [5] 37-43 (1959); Ceram. Abstracts, 1959, Nov. p. 287a. 6. F. P. Knudsen...engineering materials appropriate for conditions which require high thermal shock resistance in combination with good thermal insulating ability"C. Finally

  19. Materials selection for low temperature processed high Q resonators using ashby approach

    NARCIS (Netherlands)

    Kazmi, S.N.R.; Salm, Cora; Schmitz, Jurriaan

    2009-01-01

    MicroElectroMechanical Systems (MEMS) is an emerging class of microfabrication technology that can truly be anticipated as an enabling technology for future radio frequency (RF) communications. This work focuses on the material selection using the Ashby approach for the high-Q resonators that need

  20. Primary defect transformations in high-resistivity p-type silicon irradiated with electrons at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Makarenko, L.F., E-mail: makarenko@bsu.b [Department of Applied Mathematics and Computer Science, Belarusian State University, Independence Ave. 4, 220030 Minsk (Belarus); Lastovski, S.B.; Korshunov, F.P.; Murin, L.I. [Scientific-Practical Materials Research Centre of NAS of Belarus, Minsk (Belarus); Moll, M. [CERN, Geneva (Switzerland)

    2009-12-15

    It has been revealed that self-interstitials formed under low intensity electron irradiation in high resistivity p-type silicon can be retained frozen up to room temperature. Low thermal mobility of the self-interstitials suggests that Frenkel pairs in silicon can be stable at temperatures of about or higher than 100 K. A broad DLTS peak with activation energy of 0.14-0.17 eV can be identified as related to Frenkel pairs. This peak anneals out at temperatures of 120-140 K. Experimental evidences are presented that becoming more mobile under forward current injection the self-interstitials change their charge state to a less positive one.

  1. Neutron scattering experiments on high-temperature superconducting materials: Foreign trip report, September 13, 1988--October 4, 1988

    Science.gov (United States)

    Mook, H. A.

    1988-10-01

    The trip to the Institut Laue-Langevin (ILL) was made to perform neutron scattering experiments on the new high temperature superconducting materials. Part of this work could have been accomplished at the High Flux Isotope Reactor (HFIR) at ORNL had it been operational; other parts utilized the special instrumentation at the ILL available at no other place. Experiments performed were the following: high energy magnetic excitations in pure and Ba-doped La2CuO4, magnetic excitations and structural phase transitions in the Bi2Ba2Cu1O6 superconductor, search for the fluxoid lattice in the high temperature materials, and magnetic spin structures in ErBa2Cu3O7 and GdBa2Cu3O6.5. Measurements were also made on supermirrors important for polarizing and neutron guide applications.

  2. Fabrication of Tungsten-Rhenium Cladding materials via Spark Plasma Sintering for Ultra High Temperature Reactor Applications

    Energy Technology Data Exchange (ETDEWEB)

    Charit, Indrajit; Butt, Darryl; Frary, Megan; Carroll, Mark

    2012-11-05

    This research will develop an optimized, cost-effective method for producing high-purity tungsten-rhenium alloyed fuel clad forms that are crucial for the development of a very high-temperature nuclear reactor. The study will provide critical insight into the fundamental behavior (processing-microstructure- property correlations) of W-Re alloys made using this new fabrication process comprising high-energy ball milling (HEBM) and spark plasma sintering (SPS). A broader goal is to re-establish the U.S. lead in the research field of refractory alloys, such as W-Re systems, with potential applications in very high-temperature nuclear reactors. An essential long-term goal for nuclear power is to develop the capability of operating nuclear reactors at temperatures in excess of 1,000K. This capability has applications in space exploration and some special terrestrial uses where high temperatures are needed in certain chemical or reforming processes. Refractory alloys have been identified as being capable of withstanding temperatures in excess of 1,000K and are considered critical for the development of ultra hightemperature reactors. Tungsten alloys are known to possess extraordinary properties, such as excellent high-temperature capability, including the ability to resist leakage of fissile materials when used as a fuel clad. However, there are difficulties with the development of refractory alloys: 1) lack of basic experimental data on thermodynamics and mechanical and physical properties, and 2) challenges associated with processing these alloys.

  3. Effect of high temperatures on cement composite materials in concrete structures

    OpenAIRE

    Bodnárová, L.; Válek, J. (Jan); Sitek, L. (Libor); Foldyna, J.

    2013-01-01

    Concrete is flexible construction materi al, which is utilized in various technologica l applications for underground structures and reinforcement of mine works (adits, tunnels etc.). In such applications, concrete has ma ny functions – static function, water-tightness, gas-tightne ss, resistance to action of aggressive waters as well as durability. In case of railroad and road tunnel constructions, there is an other important problem: influence of high temp eratures on concrete li...

  4. Photo-stimulated low electron temperature high current diamond film field emission cathode

    Science.gov (United States)

    Shurter,; Roger Philips, Devlin [Los Alamos, NM; David James, Moody [Santa Fe, NM; Nathan Andrew, Taccetti [Los Alamos, NM; Jose Martin, Russell [Santa Fe, NM; John, Steven [Los Alamos, NM

    2012-07-24

    An electron source includes a back contact surface having a means for attaching a power source to the back contact surface. The electron source also includes a layer comprising platinum in direct contact with the back contact surface, a composite layer of single-walled carbon nanotubes embedded in platinum in direct contact with the layer comprising platinum. The electron source also includes a nanocrystalline diamond layer in direct contact with the composite layer. The nanocrystalline diamond layer is doped with boron. A portion of the back contact surface is removed to reveal the underlying platinum. The electron source is contained in an evacuable container.

  5. Material Solutions to Mitigate the Alkali Chloride-Induced High Temperature Corrosion

    DEFF Research Database (Denmark)

    Kiamehr, Saeed

    in the course of corrosion as well as the role of potassium chloride vapor. Results showed that while the majority of the alloys formed protective slow-growing oxides in the absence of KCl, they all suffered from significant attack when KCl was present. Thereby the inability of Cr to form a protective oxide......High temperature corrosion induced by potassium chloride (KCl) is a major challenge for biomass-based power plants. The current study aims at identification or development of alloys or coatings that can yield a better performance at a target metal temperature of 600oC compared to austenitic...... of metals. This was aimed at identifying the constituent elements of a corrosion resistant alloy. Calculations suggested Al, Si, Cr, Ti, Y, Ce, Ta, Hf and Zr as suitable oxide-forming elements as well as Mo, Ni and Co as suitable matrix-forming elements. However, the presence of potassium in the environment...

  6. Reflection high-energy electron diffraction measurements of reciprocal space structure of 2D materials.

    Science.gov (United States)

    Xiang, Y; Guo, F-W; Lu, T-M; Wang, G-C

    2016-12-02

    Knowledge on the symmetry and perfection of a 2D material deposited or transferred to a surface is very important and valuable. We demonstrate a method to map the reciprocal space structure of 2D materials using reflection high energy diffraction (RHEED). RHEED from a 2D material gives rise to 'streaks' patterns. It is shown that from these streaks patterns at different azimuthal rotation angles that the reciprocal space intensity distribution can be constructed as a function of momentum transfer parallel to the surface. To illustrate the principle, we experimentally constructed the reciprocal space structure of a commercial graphene/SiO2/Si sample in which the graphene layer was transferred to the SiO2/Si substrate after it was deposited on a Cu foil by chemical vapor deposition. The result reveals a 12-fold symmetry of the graphene layer which is a result of two dominant orientation domains with 30° rotation relative to each other. We show that the graphene can serve as a template to grow other materials such as a SnS film that follows the symmetry of graphene.

  7. The NMR probe of high-Tc materials and correlated electron systems

    CERN Document Server

    Walstedt, Russell E

    2018-01-01

    This new edition updates readers in three areas of NMR studies, namely, recent developments in high-Tc materials, heavy fermion systems and actinide oxides are presented.  The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-Tc materials, especially the advances in the area of pseudogap studies are reviewed.  An in depth overview of heavy fermion systems is presented in the second part,  notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth o...

  8. Max Phase Materials And Coatings For High Temperature Heat Transfer Applications

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Rodriguez, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Olson, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fuentes, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-19

    Molten salts have been used as heat transfer fluids in a variety of applications within proposed Gen IV nuclear designs and in advanced power system such as Concentrating Solar Power (CSP). However, operating at elevated temperatures can cause corrosion in many materials. This work developed coating technologies for MAX phase materials on Haynes-230 and characterized the corrosion of the coatings in the presence of commercial MgCl2-KCl molten salt. Cold spraying of Ti2AlC and physical vapor deposition (PVD) of Ti2AlC or Zr2AlC were tested to determine the most effective form of coating MAX phases on structural substrates. Corrosion testing at 850°C for 100 hrs showed that 3.9 μm Ti2AlC by PVD was slightly protective while 117 μm Ti2AlC by cold spray and 3.6 μm Zr2AlC by PVD were completely protective. None of the tests showed decomposition of the coating (Ti or Zr) into the salt

  9. Materials and Reliability Handbook for Semiconductor Optical and Electron Devices

    CERN Document Server

    Pearton, Stephen

    2013-01-01

    Materials and Reliability Handbook for Semiconductor Optical and Electron Devices provides comprehensive coverage of reliability procedures and approaches for electron and photonic devices. These include lasers and high speed electronics used in cell phones, satellites, data transmission systems and displays. Lifetime predictions for compound semiconductor devices are notoriously inaccurate due to the absence of standard protocols. Manufacturers have relied on extrapolation back to room temperature of accelerated testing at elevated temperature. This technique fails for scaled, high current density devices. Device failure is driven by electric field or current mechanisms or low activation energy processes that are masked by other mechanisms at high temperature. The Handbook addresses reliability engineering for III-V devices, including materials and electrical characterization, reliability testing, and electronic characterization. These are used to develop new simulation technologies for device operation and ...

  10. The thermodynamic database COST MP0602 for materials for high-temperature lead-free soldering

    Directory of Open Access Journals (Sweden)

    Kroupa A.

    2012-01-01

    Full Text Available The current state of thermodynamic modelling in the field of high-temperature lead-free soldering is presented. A consistent thermodynamic database, containing 18 elements (Ag, Al, Au, Bi, Co, Cu, Ga, Ge, Mg, Ni, P, Pb, Pd, Sb, Sn, Ti and Zn has been created. The thermodynamic data for the most of the important binary and selected ternary systems were checked and included into the database. The database was tested using major commercial software packages. Such reliable and sophisticated software coupled to reliable thermodynamic databases are necessary prerequisites for application of thermodynamics in advanced alloys design.

  11. Oxidation of UC: An in situ high temperature environmental scanning electron microscopy study

    Science.gov (United States)

    Gasparrini, Claudia; Podor, Renaud; Horlait, Denis; Rushton, Michael J. D.; Fiquet, Olivier; Lee, William Edward

    2017-10-01

    In situ HT-ESEM oxidation of sintered UC fragments revealed the morphological changes occurring during the transformation between UC to UO2 and UO2 to U3O8 at 723-848 K and in an atmosphere of 10-100 Pa O2. Two main oxidation pathways were revealed. Oxidation at 723 K in atmospheres ≤25 Pa O2 showed the transformation from UC to UO2+x, as confirmed by post mortem HRTEM analysis. This oxidation pathway was comprised of three steps: (i) an induction period, where only surface UC particles oxidised, (ii) a sample area expansion accompanied by crack formation and propagation, (iii) a stabilisation of the total crack length inferring that crack propagation had stopped. Samples oxidised under 50 Pa O2 at 723 K and at 773-848 K for 10-100 Pa O2 showed an ;explosive; oxidation pathway: (i) sample area expansion occurred as soon as oxygen was inserted into the chamber and crack propagation and crack length followed an exponential law; (ii) cracks propagated as a network and the oxide layer fragmented, (iii) an ;explosion; occurred causing a popcorn-like transformation, typical for oxidation from UO2 to U3O8. HRTEM characterisation revealed U3O8 preferentially grow in the [001] direction. The explosive growth, triggered by ignition of UC, proceeded as a self-propagating high-temperature synthesis reaction, with a propagation speed of 150-500 ± 50 μm/s.

  12. Upgrade possibilities for continuous wave rf electron guns based on room-temperature very high frequency technology

    Science.gov (United States)

    Sannibale, F.; Filippetto, D.; Johnson, M.; Li, D.; Luo, T.; Mitchell, C.; Staples, J.; Virostek, S.; Wells, R.; Byrd, J. M.

    2017-11-01

    The past decade was characterized by an increasing scientific demand for extending towards higher repetition rates (MHz class and beyond) the performance of already operating lower repetition rate accelerator-based instruments such as x-ray free electron lasers (FELs) and ultrafast electron diffraction (UED) and microscopy (UEM) instruments. Such a need stimulated a worldwide spread of a vibrant R&D activity targeting the development of high-brightness electron sources capable of operating at these challenging rates. Among the different technologies pursued, rf guns based on room-temperature structures resonating in the very high frequency (VHF) range (30-300 MHz) and operating in continuous wave successfully demonstrated in the past few years the targeted brightness and reliability. Nevertheless, recently proposed upgrades for x-ray FELs and the always brightness-frontier applications such as UED and UEM are now requiring a further step forward in terms of beam brightness in electron sources. In this paper, we present a few possible upgrade paths that would allow one to extend, in a relatively simple and cost-effective way, the performance of the present VHF technology to the required new goals.

  13. Upgrade possibilities for continuous wave rf electron guns based on room-temperature very high frequency technology

    Directory of Open Access Journals (Sweden)

    F. Sannibale

    2017-11-01

    Full Text Available The past decade was characterized by an increasing scientific demand for extending towards higher repetition rates (MHz class and beyond the performance of already operating lower repetition rate accelerator-based instruments such as x-ray free electron lasers (FELs and ultrafast electron diffraction (UED and microscopy (UEM instruments. Such a need stimulated a worldwide spread of a vibrant R&D activity targeting the development of high-brightness electron sources capable of operating at these challenging rates. Among the different technologies pursued, rf guns based on room-temperature structures resonating in the very high frequency (VHF range (30–300 MHz and operating in continuous wave successfully demonstrated in the past few years the targeted brightness and reliability. Nevertheless, recently proposed upgrades for x-ray FELs and the always brightness-frontier applications such as UED and UEM are now requiring a further step forward in terms of beam brightness in electron sources. In this paper, we present a few possible upgrade paths that would allow one to extend, in a relatively simple and cost-effective way, the performance of the present VHF technology to the required new goals.

  14. Study on the Effects of Liquid Thermal Media on the Irradiation Capsule of High-Temperature Materials

    Directory of Open Access Journals (Sweden)

    Man Soon Cho

    2015-01-01

    Full Text Available Irradiation tests of materials at HANARO have usually been conducted using a standard capsule at temperatures of about 300°C for irradiation of materials used at PWR. Thus, the standard capsule uses aluminum as the specimen holder, which acts to dissipate the thermal energy. Future nuclear systems such as a VHTR and SFR require the irradiation tests at a relatively high temperature. As an alternative to aluminum which has been used as the thermal media in a standard material capsule, the characteristics of liquid metals such as NaK and LBE are reviewed. The temperatures of the capsule are affected by the variation of parameters such as the gap and wall thickness of the container. In particular, the external gap is most important in determining the temperature of the specimen. LBE raises the temperature of the specimen higher than NaK at the same configuration of the capsule. Thus, LBE can lessen the gap of the parts and reduce the vibration for a stable long-term test in reactor.

  15. High speed, high temperature electrical characterization of phase change materials: metastable phases, crystallization dynamics, and resistance drift.

    Science.gov (United States)

    Dirisaglik, Faruk; Bakan, Gokhan; Jurado, Zoila; Muneer, Sadid; Akbulut, Mustafa; Rarey, Jonathan; Sullivan, Lindsay; Wennberg, Maren; King, Adrienne; Zhang, Lingyi; Nowak, Rebecca; Lam, Chung; Silva, Helena; Gokirmak, Ali

    2015-10-28

    During the fast switching in Ge2Sb2Te5 phase change memory devices, both the amorphous and fcc crystalline phases remain metastable beyond the fcc and hexagonal transition temperatures respectively. In this work, the metastable electrical properties together with crystallization times and resistance drift behaviour of GST are studied using a high-speed, device-level characterization technique in the temperature range of 300 K to 675 K.

  16. Iron Disilicide as High-Temperature Reference Material for Traceable Measurements of Seebeck Coefficient Between 300 K and 800 K

    Science.gov (United States)

    Ziolkowski, Pawel; Stiewe, Christian; de Boor, Johannes; Druschke, Ines; Zabrocki, Knud; Edler, Frank; Haupt, Sebastian; König, Jan; Mueller, Eckhard

    2017-01-01

    Thermoelectric generators (TEGs) convert heat to electrical energy by means of the Seebeck effect. The Seebeck coefficient is a central thermoelectric material property, measuring the magnitude of the thermovoltage generated in response to a temperature difference across a thermoelectric material. Precise determination of the Seebeck coefficient provides the basis for reliable performance assessment in materials development in the field of thermoelectrics. For several reasons, measurement uncertainties of up to 14% can often be observed in interlaboratory comparisons of temperature-dependent Seebeck coefficient or in error analyses on currently employed instruments. This is still too high for an industrial benchmark and insufficient for many scientific investigations and technological developments. The TESt (thermoelectric standardization) project was launched in 2011, funded by the German Federal Ministry of Education and Research (BMBF), to reduce measurement uncertainties, engineer traceable and precise thermoelectric measurement techniques for materials and TEGs, and develop reference materials (RMs) for temperature-dependent determination of the Seebeck coefficient. We report herein the successful development and qualification of cobalt-doped β-iron disilicide ( β-Fe0.95Co0.05Si2) as a RM for high-temperature thermoelectric metrology. A brief survey on technological processes for manufacturing and machining of samples is presented. Focus is placed on metrological qualification of the iron disilicide, results of an international round-robin test, and final certification as a reference material in accordance with ISO-Guide 35 and the "Guide to the expression of uncertainty in measurement" by the Physikalisch-Technische Bundesanstalt, the national metrology institute of Germany.

  17. Three-dimensional mesostructures as high-temperature growth templates, electronic cellular scaffolds, and self-propelled microrobots

    Science.gov (United States)

    Yan, Zheng; Han, Mengdi; Shi, Yan; Badea, Adina; Yang, Yiyuan; Kulkarni, Ashish; Hanson, Erik; Kandel, Mikhail E.; Wen, Xiewen; Zhang, Fan; Luo, Yiyue; Lin, Qing; Zhang, Hang; Guo, Xiaogang; Huang, Yuming; Nan, Kewang; Jia, Shuai; Oraham, Aaron W.; Mevis, Molly B.; Lim, Jaeman; Guo, Xuelin; Gao, Mingye; Ryu, Woomi; Yu, Ki Jun; Nicolau, Bruno G.; Petronico, Aaron; Rubakhin, Stanislav S.; Lou, Jun; Ajayan, Pulickel M.; Thornton, Katsuyo; Popescu, Gabriel; Fang, Daining; Sweedler, Jonathan V.; Braun, Paul V.; Zhang, Haixia; Nuzzo, Ralph G.; Huang, Yonggang; Zhang, Yihui; Rogers, John A.

    2017-11-01

    Recent work demonstrates that processes of stress release in prestrained elastomeric substrates can guide the assembly of sophisticated 3D micro/nanostructures in advanced materials. Reported application examples include soft electronic components, tunable electromagnetic and optical devices, vibrational metrology platforms, and other unusual technologies, each enabled by uniquely engineered 3D architectures. A significant disadvantage of these systems is that the elastomeric substrates, while essential to the assembly process, can impose significant engineering constraints in terms of operating temperatures and levels of dimensional stability; they also prevent the realization of 3D structures in freestanding forms. Here, we introduce concepts in interfacial photopolymerization, nonlinear mechanics, and physical transfer that bypass these limitations. The results enable 3D mesostructures in fully or partially freestanding forms, with additional capabilities in integration onto nearly any class of substrate, from planar, hard inorganic materials to textured, soft biological tissues, all via mechanisms quantitatively described by theoretical modeling. Illustrations of these ideas include their use in 3D structures as frameworks for templated growth of organized lamellae from AgCl–KCl eutectics and of atomic layers of WSe2 from vapor-phase precursors, as open-architecture electronic scaffolds for formation of dorsal root ganglion (DRG) neural networks, and as catalyst supports for propulsive systems in 3D microswimmers with geometrically controlled dynamics. Taken together, these methodologies establish a set of enabling options in 3D micro/nanomanufacturing that lie outside of the scope of existing alternatives.

  18. ECE imaging of electron temperature and electron temperature fluctuations (invited)

    NARCIS (Netherlands)

    Deng, B.H.; Domier, C.W.; N C Luhmann Jr.,; Brower, D.L.; Cima, G.; Donne, A. J. H.; Oyevaar, T.; van de Pol, M.J.

    2001-01-01

    Electron cyclotron emission imaging (ECE imaging or ECEI) is a novel plasma diagnostic technique for the study of electron temperature profiles and fluctuations in magnetic fusion plasma devices. Instead of a single receiver located in the tokamak midplane as in conventional ECE radiometers, ECEI

  19. Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

    Science.gov (United States)

    Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

    1987-01-01

    Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

  20. Direct ethanol production from cellulosic materials at high temperature using the thermotolerant yeast Kluyveromyces marxianus displaying cellulolytic enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Yanase, Shuhei; Yamada, Ryosuke; Ogino, Chiaki; Kondo, Akihiko [Kobe Univ. (Japan). Dept. of Chemical Science and Engineering; Hasunuma, Tomohisa; Tanaka, Tsutomu; Fukuda, Hideki [Kobe Univ. (Japan). Organization of Advanced Science and Technology

    2010-09-15

    To exploit cellulosic materials for fuel ethanol production, a microorganism capable of high temperature and simultaneous saccharification-fermentation has been required. However, a major drawback is the optimum temperature for the saccharification and fermentation. Most ethanol-fermenting microbes have an optimum temperature for ethanol fermentation ranging between 28 C and 37 C, while the activity of cellulolytic enzymes is highest at around 50 C and significantly decreases with a decrease in temperature. Therefore, in the present study, a thermotolerant yeast, Kluyveromyces marxianus, which has high growth and fermentation at elevated temperatures, was used as a producer of ethanol from cellulose. The strain was genetically engineered to display Trichoderma reesei endoglucanase and Aspergillus aculeatus {beta}-glucosidase on the cell surface, which successfully converts a cellulosic {beta}-glucan to ethanol directly at 48 C with a yield of 4.24 g/l from 10 g/l within 12 h. The yield (in grams of ethanol produced per gram of {beta}-glucan consumed) was 0.47 g/g, which corresponds to 92.2% of the theoretical yield. This indicates that high-temperature cellulose fermentation to ethanol can be efficiently accomplished using a recombinant K. marxianus strain displaying thermostable cellulolytic enzymes on the cell surface. (orig.)

  1. Characterization of free radicals by electron spin resonance spectroscopy in biochars from pyrolysis at high heating rates and at high temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Jensen, Peter Arendt; Jensen, Anker Degn

    2016-01-01

    The concentration and type of free radicals from the decay (termination stage) of pyrolysis at slow and fast heating rates and at high temperatures (above 1000°C) in biomass char have been studied. A room temperature electron spin resonance spectroscopy study was conducted on original wood......, herbaceous biomass, holocelluloses, lignin and their chars, prepared at high temperatures in a wire mesh reactor, an entrained flow reactor, and a tubular reactor. The radical concentrations in the chars from the decay stage range up between 7·1016 and 1.5·1018 spins g -1. The results indicated....... The results show that at high temperatures, mostly aliphatic radicals (g = 2.0026-2.0028) and PAH radicals (g = 2.0027e2.0031) were formed....

  2. Method and apparatus for studying high-temperature properties of conductive materials in the interests of nuclear power engineering

    Energy Technology Data Exchange (ETDEWEB)

    Savvatimskiy, A. I., E-mail: savva@iht.mpei.ac.ru; Onufriev, S. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2016-12-15

    Physical processes during a rapid (microsecond) heating of metals, carbon, and their compounds by a single pulse of electric current are discussed. Effects arising in such short-term heating near the melting point are noted: the electron emission and heat capacity anomalies and the possible occurrence of Frenkel pair (interstitial atom and vacancy). The problem of measuring the temperature using optical methods under pulse heating is considered, including the use of a specimen in the form of a blackbody model. The melting temperature of carbon (4800–4900 K) is measured at increased pulse pressure. The results of studying the properties of metals (by example of zirconium and hafnium) and of zirconium carbide at high temperatures are discussed. The schematics of the pulse setups and the instrumentation, as well as specimens for a pulse experiment, are presented.

  3. High Momentum Particle Identification Detector The Study of Cesium Iodide Quantum Efficiency Dependency on Substrate Material, Temperature and Quartz Window

    CERN Document Server

    Wisna, Gde Bimananda M

    2014-01-01

    The Cesium Iodide (CsI) is used as a material for detecting Cherenkov radiation produced by high momentum particle in High Momentum Particle Identification Detector (HMPID) at ALICE Experiment at CERN. This work provides investigation and analysis of The Quantum Efficiency (QE) result of CsI which is deposited on five samples substrates such as copper passivated red, copper passivated yellow, aluminium, copper coated with nickel and copper coated with nickel then coated with gold. The measurement of five samples is held under temperature $60^{0}$ C and $25^{0}$ C (room temperature) and also with optical quartz window which can be adjusted to limit the wavelength range which reach the CsI. The result shows there are dependency of substrate, temperature due to enhancement effect and also quartz windows usage on QE of CsI. The results of five samples is then compared and analyzed.

  4. A new architecture for a factual materials database on coatings and high temperature corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Streiff, R.; Vaugelade, S. [Univ. de Provence, Marseille (France); Komornicki, S. [Akademia Gorniczo-Hutnicza, Cracow (Poland); Boone, D.H. [Boone and Associates, Walnut Creek, CA (United States)

    1997-12-31

    C and HTC-DATA a data bank on coatings and high temperature corrosion, has been created to help in choosing coatings for specific applications, knowing their fabrication process characteristics and their protectivity characteristics. This relational data bank will include five databases, viz. (1) a bibliographic reference data base, (2) a directory of addresses of companies and researchers involved in the field, (3) a numerical database on alloy composition, (4) a factual coatings database, and (5) a factual corrosion database. Building of these factual databases first followed the classical MERISE analytical treatment for data organisation. However, the variety of coating characteristics has resulted in a very complex database structure with a very large number of tables and fields. Therefore, a new approach for the architecture of the coating database based upon a thesaurus to describe the data has been perfected which is presented in this paper. (orig.) 13 refs.

  5. Electron Attachment to C2 Fluorocarbon Radicals at High Temperature (Postprint)

    Science.gov (United States)

    2016-01-28

    constant curve for C2F3. Figure 3 shows an extrap - olation of the electron attachment rate constant for C2F3 as a function of Tgas and Tel similar to...weight to the use of kinetic modeling to extrap - olate data taken over narrower ranges. ACKNOWLEDGMENTS The project was funded by the United States Air

  6. High-temperature stability of electron transport in semiconductors with strong spin-orbital interaction

    Science.gov (United States)

    Tomaka, G.; Grendysa, J.; ŚliŻ, P.; Becker, C. R.; Polit, J.; Wojnarowska, R.; Stadler, A.; Sheregii, E. M.

    2016-05-01

    Experimental results of the magnetotransport measurements (longitudinal magnetoresistance Rx x and the Hall resistance Rx y) are presented over a wide interval of temperatures for several samples of Hg1 -xCdxTe (x ≈0.13 -0.15 ) grown by MBE—thin layers (thickness about 100 nm) strained and not strained and thick ones with thickness about 1 μ m . An amazing temperature stability of the SdH-oscillation period and amplitude is observed in the entire temperature interval of measurements up to 50 K. Moreover, the quantum Hall effect (QHE) behavior of the Hall resistance is registered in the same temperature interval. These peculiarities of the Rx x and Rx y for strained thin layers are interpreted using quantum Hall conductivity (QHC) on topologically protected surface states (TPSS) [C. Brüne et al., Phys. Rev. Lett. 106, 126803 (2011), 10.1103/PhysRevLett.106.126803]. In the case of not strained layers it is assumed that the QHC on the TPSS (or on the resonant interface states) contributes also to the conductance of the bulk samples.

  7. The influence of hybrid alumina/titania materials as electron transmission layer in planar high-performance perovskite solar cells

    Science.gov (United States)

    Yuan, Songyang; Xia, Chao; Zhang, Chongzhen; Song, Weidong; Qi, Mingyue; Wang, Rupeng; Zhao, Liangliang; Li, Shuti

    2017-11-01

    As one of main layers in hybrid organic-inorganic perovskite solar cells (PSCs), electron transport materials (ETM) play an important role in getting high photoelectric conversion efficiency (PCE). Here, we investigate Al2O3/TiO2 hybrid materials as electron transmission layer in planar perovskite solar cells. The hybrid Al2O3/TiO2 material is proved to induce a better crystal quality of CH3NH3PbCl3- x I x perovskite layer as confirmed by X-ray diffractometer (XRD). The new-formed compact rough surface of ETM is responsible for the better excited electron transmission and light absorption, thus resulting in the improvement of short-circuit current ( J sc). Meanwhile, the embedded Al2O3 plays a key role in shifting the conduction band edge of ETM, thereby leading to the improvement of photo-voltage. The optimal value is obtained with the test of sequential changing Al2O3/TiO2 concentration ratio. Compared to the device with pure TiO2 as ETM, the devices assembled with Al2O3/TiO2 hybrid ETM showed improvement in J sc (from 13.65 to 18.71 mA/cm2) as well as in V oc (from 0.95 to 1.00 V), which brings about 27.6% enhancement in PCE based on the multifunctional hybrid TiO2/ Al2O3 ETM.

  8. Development of a nuclear magnetic resonance system for in situ analysis of hydrogen storage materials under high pressures and temperatures.

    Science.gov (United States)

    Hashimoto, S; Noda, Y; Maekawa, H; Takamura, H; Fujito, T; Moriya, J; Ikeda, T

    2010-10-01

    A NMR system for in situ analysis of hydrogen storage materials under high pressure and temperature conditions was developed. The system consists of a gas pressure and flow rate controlling unit, a temperature controller, a high temperature NMR probe tunable for both (1)H and other nuclei, and a sample tube holder. Sample temperature can be controlled up to 623 K by heated N(2) gas flow. Sample tube atmosphere can be substituted by either H(2) or Ar and can be pressurized up to 1 MPa under constant flow rate up to 100 ml/min. During the NMR measurement, the pressure can be adjusted easily by just handle a back pressure valve. On the blank NMR measurement, (1)H background noise was confirmed to be very low. (1)H and (11)B NMR spectrum of LiBH(4) were successfully observed at high temperature for the demonstration of the system. The intensity of the (1)H NMR spectra of H(2) gas was also confirmed to be proportional to the applied pressure.

  9. Ion beam processing of advanced electronic materials

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B. (eds.) (California Univ., Berkeley, CA (USA); International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center; Oak Ridge National Lab., TN (USA))

    1989-01-01

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)

  10. Fabrication of organic semiconducting materials and high-performance organic thin-film transistors based on electron-irradiated polystyrene

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeok Moo

    2011-02-15

    It was discovered that non-luminescent polystyrene (PS) can be converted to luminescent materials whose color can be changed in a wide visible range by electron irradiation. After the analyses of electron-irradiated PS, it was found that polycyclic aromatic hydrocarbons are produced by the irradiation and these PAHs are the origin of the luminescence from the electron-irradiated polymer. Based on the finding, a straightforward approach to produce desired light-emitting nanoarchitectures and nanopatterns only by irradiating an electron beam to the polymer was presented. In particular, the top-down irradiation approach provides a powerful tool to fabricate a variety of interesting nanoarchitectures when combined with bottom-up approaches; PS nanostructures prepared by self-assembling techniques can be directly transformed to luminescent nanostructures by electron irradiation while keeping their pristine morphologies. Light-emitting materials are widely used for optical, photonic, chemical and biomedical devices and a rapid progress in the devices requires well-defined luminescent nanoarchitectures. The approach presented here will be useful for a wide range of research fields including optics, photonics, chemistry, and biologics. On the other hand, a very simple but effective approach to produce high-performance rubrene organic thin-film transistors (OTFTs) with characteristics better than amorphous silicon TFTs was presented. Only by an abrupt heating process, high-quality crystalline rubrene semiconductor thin films that have almost ideal structures for OTFTs are created. The produced crystalline thin films consist of highly ordered, uniaxially oriented single-crystalline grains with large average sizes and the grains are interconnected with one another to form continuous films over the whole dielectric surfaces. Such high-quality crystalline rubrene thin films are remarkably rapidly produced in just 30 sec through this approach. Moreover, the increase of carrier

  11. Nanostructured electronic and magnetic materials

    Indian Academy of Sciences (India)

    Research and development in nanostructured materials is one of the most intensely studied areas in science. As a result of concerted R & D efforts, nanostructured electronic and magnetic materials have achieved commercial success. Specific examples of novel industrially important nanostructured electronic and magnetic ...

  12. Advanced High Energy Density Secondary Batteries with Multi‐Electron Reaction Materials

    National Research Council Canada - National Science Library

    Chen, Renjie; Luo, Rui; Huang, Yongxin; Wu, Feng; Li, Li

    2016-01-01

    ...‐electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems...

  13. Soot structure and reactivity analysis by Raman microspectroscopy, temperature-programmed oxidation, and high-resolution transmission electron microscopy.

    Science.gov (United States)

    Knauer, Markus; Schuster, Manfred E; Su, Dangsheng; Schlögl, Robert; Niessner, Reinhard; Ivleva, Natalia P

    2009-12-17

    Raman microspectroscopy (RM), temperature-programmed oxidation (TPO), high-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS) were combined to get comprehensive information on the relationship between structure and reactivity of soot in samples of spark discharge (GfG), heavy duty engine diesel (EURO VI and IV) soot, and graphite powder upon oxidation by oxygen at increasing temperatures. GfG soot and graphite powder represent the higher and lower reactivity limits. Raman microspectroscopic analysis was conducted by determination of spectral parameters using a five band fitting procedure (G, D1-D4) as well as by evaluation of the dispersive character of the D mode. The analysis of spectral parameters shows a higher degree of disorder and a higher amount of molecular carbon for untreated GfG soot samples than for samples of untreated EURO VI and EURO IV soot. The structural analysis based on the dispersive character of the D mode revealed substantial differences in ordering descending from graphite powder, EURO IV, VI to GfG soot. HRTEM images and EELS analysis of EURO IV and VI samples indicated a different morphology and a higher structural order as compared to GfG soot in full agreement with the Raman analysis. These findings are also confirmed by the reactivity of soot during oxidation (TPO), where GfG soot was found to be the most reactive and EURO IV and VI soot samples exhibited a moderate reactivity.

  14. Advanced High Energy Density Secondary Batteries with Multi?Electron Reaction Materials

    OpenAIRE

    Chen, Renjie; Luo, Rui; Huang, Yongxin; Wu, Feng; Li, Li

    2016-01-01

    Secondary batteries have become important for smart grid and electric vehicle applications, and massive effort has been dedicated to optimizing the current generation and improving their energy density. Multi?electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems that meet energy density requirements. An in?depth understanding of multi?electron chemistries i...

  15. High Temperature Steam Oxidation Testing of Candidate Accident Tolerant Fuel Cladding Materials

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nelson, Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parkison, Adam [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2013-12-23

    > formation, which reacted with the specimen to form a liquid reaction product. This behavior was not observed at lower temperatures where gas velocity and H2O content showed typical effects on the reaction rate. For LANL, the capabilities for oxidation testing as well as exploration of a methodology for measurement of hydrogen production of samples during oxidation under water vapor atmospheres is discussed. Results obtained for available commercial alloys are summarized, and data highlighting the performance of molybdenum, a recently proposed cladding material, are presented. Finally, leveraging of these techniques in conjunction with current and companion FCRD programs is discussed with respect to work in FY14.

  16. Self-heating probe instrument and method for measuring high temperature melting volume change rate of material

    Science.gov (United States)

    Wang, Junwei; Wang, Zhiping; Lu, Yang; Cheng, Bo

    2013-03-01

    The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF+CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg·m-3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.

  17. History and modern applications of nano-composite materials carrying GA/cm2 current density due to a Bose-Einstein Condensate at room temperature produced by Focused Electron Beam Induced Processing for many extraordinary novel technical applications

    Science.gov (United States)

    Koops, Hans W. P.

    2015-12-01

    The discovery of Focused Electron Beam Induced Processing and early applications of this technology led to the possible use of a novel nanogranular material “Koops-GranMat®” using Pt/C and Au/C material. which carries at room temperature a current density > 50 times the current density which high TC superconductors can carry. The explanation for the characteristics of this novel material is given. This fact allows producing novel products for many applications using Dual Beam system having a gas supply and X.Y.T stream data programming and not using GDSII layout pattern control software. Novel products are possible for energy transportation. -distribution.-switching, photon-detection above 65 meV energy for very efficient energy harvesting, for bright field emission electron sources used for vacuum electronic devices like amplifiers for HF electronics, micro-tubes, 30 GHz to 6 THz switching amplifiers with signal to noise ratio >10(!), THz power sources up to 1 Watt, in combination with miniaturized vacuum pumps, vacuum gauges, IR to THz detectors, EUV- and X-Ray sources. Since focusing electron beam induced deposition works also at low energy, selfcloning multibeam-production machines for field emitter lamps, displays, multi-beam - lithography, - imaging, and - inspection, energy harvesting, and power distribution with switches controlling field-emitter arrays for KA of currents but with < 100 V switching voltage are possible. Finally the replacement of HTC superconductors and its applications by the Koops-GranMat® having Koops-Pairs at room temperature will allow the investigation devices similar to Josephson Junctions and its applications now called QUIDART (Quantum interference devices at Room Temperature). All these possibilities will support a revolution in the optical, electric, power, and electronic technology.

  18. Method of making bearing materials. [self-lubricating, oxidation resistant composites for high temperature applications

    Science.gov (United States)

    Sliney, H. E. (Inventor)

    1979-01-01

    A method is described for making a composite material which provides low friction surfaces for materials in rolling or sliding contact. The composite material which is self-lubricating and oxidation resistant up to and in excess of about 930 C is comprised of a metal component which lends strength and elasticity to the structure and a fluorine salt component which provides oxidation protection to the metal but may also enhance the lubrication qualities of the composite.

  19. A Brief Description of High Temperature Solid Oxide Fuel Cell’s Operation, Materials, Design, Fabrication Technologies and Performance

    Directory of Open Access Journals (Sweden)

    Muneeb Irshad

    2016-03-01

    Full Text Available Today’s world needs highly efficient systems that can fulfill the growing demand for energy. One of the promising solutions is the fuel cell. Solid oxide fuel cell (SOFC is considered by many developed countries as an alternative solution of energy in near future. A lot of efforts have been made during last decade to make it commercial by reducing its cost and increasing its durability. Different materials, designs and fabrication technologies have been developed and tested to make it more cost effective and stable. This article is focused on the advancements made in the field of high temperature SOFC. High temperature SOFC does not need any precious catalyst for its operation, unlike in other types of fuel cell. Different conventional and innovative materials have been discussed along with properties and effects on the performance of SOFC’s components (electrolyte anode, cathode, interconnect and sealing materials. Advancements made in the field of cell and stack design are also explored along with hurdles coming in their fabrication and performance. This article also gives an overview of methods required for the fabrication of different components of SOFC. The flexibility of SOFC in terms fuel has also been discussed. Performance of the SOFC with varying combination of electrolyte, anode, cathode and fuel is also described in this article.

  20. Development of high temperature materials for solid propellant rocket nozzle applications

    Science.gov (United States)

    Manning, C. R., Jr.; Lineback, L. D.

    1974-01-01

    Aspects of the development and characteristics of thermal shock resistant hafnia ceramic material for use in solid propellant rocket nozzles are presented. The investigation of thermal shock resistance factors for hafnia based composites, and the preparation and analysis of a model of elastic materials containing more than one crack are reported.

  1. Reliable Direct Bond Copper Ceramic Packages for High Temperature Power Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed program will develop highly reliable, hermetic, Si3N4 ceramic multichip modules to integrate commercially available SiC power devices to build power...

  2. Tungsten as a plasma-facing material in fusion devices: impact of helium high-temperature irradiation on hydrogen retention and damages in the material

    Science.gov (United States)

    Bernard, E.; Sakamoto, R.; Kreter, A.; Barthe, M. F.; Autissier, E.; Desgardin, P.; Yamada, H.; Garcia-Argote, S.; Pieters, G.; Chêne, J.; Rousseau, B.; Grisolia, C.

    2017-12-01

    Plasma-facing materials for next generation fusion devices, like ITER and DEMO, have to withstand intense fluxes of light elements (notably helium and hydrogen isotopes). For tungsten (W), helium (He) irradiation leads to major changes in the material morphology, rising concerns about properties such as material structure conservation and hydrogen (H) retention. The impact of preceeding He irradiation conditions (temperature, flux and fluence) on H trapping were investigated on a set of W samples exposed to the linear plasma device PSI-2. Positron annihilation spectroscopy (PAS) was carried out to probe the free volume of defects created by the He exposure in the W structure at the atomic scale. In parallel, tritium (T) inventory after exposure was evaluated through T gas loading and desorption at the Saclay Tritium Lab. First, we observed that the material preparation prior to He irradiation was crucial, with a major reduction of the T trapping when W was annealed at 1773 K for 2 h compared to the as-received material. PAS study confirms the presence of He in the bubbles created in the material surface layer, whose dimensions were previously characterized by transmission electron microscopy and grazing-incidence small-angle x-ray scattering, and demonstrates that even below the minimal energy for displacement of He in W, defects are created in almost all He irradiation conditions. The T loading study highlights that increasing the He fluence leads to higher T inventory. Also, for a given fluence, increasing the He flux reduces the T trapping. The very first steps of a parametric study were set to understand the mechanisms at stake in those observed material modifications, confirming the need to pursue the study with a more complete set of surface and irradiation conditions.

  3. Synthesis, characterization and thermal properties of polymers based composites materials for High Power Electronic Packaging Applications

    OpenAIRE

    Spitaleri, Fabiola

    2015-01-01

    As devices evolve, it s necessary that also interconnections and all hardware circuits evolve, including packaging. Nowadays are required significant improvement in packaging properties: low resistance interconnections, less noise, less parasitic oscillations, increased reliability and improved thermal behaviour. For these purpose has designed a research activity for the synthesis of new composites materials capable to dissipating heat better in relation to the current ones. These material...

  4. Thermophysical characterization tools and numerical models for high temperature thermo-structural composite materials; Outils de caracterisation thermophysique et modeles numeriques pour les composites thermostructuraux a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lorrette, Ch

    2007-04-15

    This work is an original contribution to the study of the thermo-structural composite materials thermal behaviour. It aims to develop a methodology with a new experimental device for thermal characterization adapted to this type of material and to model the heat transfer by conduction within these heterogeneous media. The first part deals with prediction of the thermal effective conductivity of stratified composite materials in the three space directions. For that, a multi scale model using a rigorous morphology analysis of the structure and the elementary properties is proposed and implemented. The second part deals with the thermal characterization at high temperature. It shows how to estimate simultaneously the thermal effusiveness and the thermal conductivity. The present method is based on the observation of the heating from a plane sample submitted to a continuous excitation generated by Joule Effect. Heat transfer is modelled with the quadrupole formalism, temperature is here measured on two sides of the sample. The development of both resistive probes for excitation and linear probes for temperature measurements enables the thermal properties measured up to 1000 C. Finally, some experimental and numerical application examples lead to review the obtained results. (author)

  5. High temperature corrosion of advanced ceramic materials for hot gas filters. Topical report for part 1 of high temperature corrosion of advanced ceramic materials for hot gas filters and heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Spear, K.E.; Crossland, C.E.; Shelleman, D.L.; Tressler, R.E. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering

    1997-12-11

    This program consists of two separate research areas. Part 1, for which this report is written, studied the high temperature corrosion of advanced ceramic hot gas filters, while Part 2 studied the long-term durability of ceramic heat exchangers to coal combustion environments. The objectives of Part 1 were to select two candidate ceramic filter materials for flow-through hot corrosion studies and subsequent corrosion and mechanical properties characterization. In addition, a thermodynamic database was developed so that thermochemical modeling studies could be performed to simulate operating conditions of laboratory reactors and existing coal combustion power plants, and to predict the reactions of new filter materials with coal combustion environments. The latter would make it possible to gain insight into problems that could develop during actual operation of filters in coal combustion power plants so that potential problems could be addressed before they arise.

  6. Weavable and Highly Efficient Organic Light-Emitting Fibers for Wearable Electronics: A Scalable, Low-Temperature Process.

    Science.gov (United States)

    Kwon, Seonil; Kim, Hyuncheol; Choi, Seungyeop; Jeong, Eun Gyo; Kim, Dohong; Lee, Somin; Lee, Ho Seung; Seo, Young Cheol; Choi, Kyung Cheol

    2018-01-10

    Fiber-based wearable displays, one of the most desirable requisites of electronic textiles (e-textiles), have emerged as a technology for their capability to revolutionize textile and fashion industries in collaboration with the state-of-the-art electronics. Nonetheless, challenges remain for the fibertronic approaches, because fiber-based light-emitting devices suffer from much lower performance than those fabricated on planar substrates. Here, we report weavable and highly efficient fiber-based organic light-emitting diodes (fiber OLEDs) based on a simple, cost-effective and low-temperature solution process. The values obtained for the fiber OLEDs, including efficiency and lifetime, are similar to that of conventional glass-based counterparts, which means that these state-of-the-art, highly efficient solution processed planar OLEDs can be applied to cylindrical shaped fibers without a reduction in performance. The fiber OLEDs withstand tensile strain up to 4.3% at a radius of 3.5 mm and are verified to be weavable into textiles and knitted clothes by hand-weaving demonstrations. Furthermore, to ensure the scalability of the proposed scheme fiber OLEDs with several diameters of 300, 220, 120, and 90 μm, thinner than a human hair, are demonstrated successfully. We believe that this approach, suitable for cost-effective reel-to-reel production, can realize low-cost commercially feasible fiber-based wearable displays in the future.

  7. Lightweight High Temperature Non-Eroding Throat Materials for Propulsion Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation in this proposed effort is the development of lightweight, non-eroding nozzle materials for use in propulsion systems. Lightweight structures are...

  8. Synthesis of Hafnium-Based Ceramic Materials for Ultra-High Temperature Aerospace Applications

    Science.gov (United States)

    Johnson, Sylvia; Feldman, Jay

    2004-01-01

    This project involved the synthesis of hafnium (Hf)-based ceramic powders and Hf-based precursor solutions that were suitable for preparation of Hf-based ceramics. The Hf-based ceramic materials of interest in this project were hafnium carbide (with nominal composition HE) and hafnium dioxide (HfO2). The materials were prepared at Georgia Institute of Technology and then supplied to research collaborators Dr. Sylvia Johnson and Dr. Jay Feldman) at NASA Ames Research Center.

  9. Tungsten as a Chemically-Stable Electrode Material on Ga-Containing Piezoelectric Substrates Langasite and Catangasite for High-Temperature SAW Devices

    Directory of Open Access Journals (Sweden)

    Gayatri K. Rane

    2016-02-01

    Full Text Available Thin films of tungsten on piezoelectric substrates La3Ga5SiO14 (LGS and Ca3TaGa3Si2O14 (CTGS have been investigated as a potential new electrode material for interdigital transducers for surface acoustic wave-based sensor devices operating at high temperatures up to 800 °C under vacuum conditions. Although LGS is considered to be suitable for high-temperature applications, it undergoes chemical and structural transformation upon vacuum annealing due to diffusion of gallium and oxygen. This can alter the device properties depending on the electrode nature, the annealing temperature, and the duration of the application. Our studies present evidence for the chemical stability of W on these substrates against the diffusion of Ga/O from the substrate into the film, even upon annealing up to 800 °C under vacuum conditions using Auger electron spectroscopy and energy-dispersive X-ray spectroscopy, along with local studies using transmission electron microscopy. Additionally, the use of CTGS as a more stable substrate for such applications is indicated.

  10. GaAs/GaN Strained Layer Superlattice Materials for High Temperature Transistors. Phase 1

    Science.gov (United States)

    1994-01-10

    where It breaks down Into ASH2. A special scrubber is then used to remove the As species. Fast Vent Switching Manifold H2i Reactor 2 I TBA Carbon... Scrubber IAccesion For IMO By Pass -_ ---slo Io MB aNTIS CRA&I Temperature DTIC TAB El Controller Unannounced El Vacuum Justftcjticw; Pump i _y Dit O...an Intermittent supply of TBA (the As source) and a constant supply of NH3 (the N source). At these low temperatures As will dominate the Incorporation

  11. Investigation of the thermal expansion of the refractory materials at high temperatures

    Science.gov (United States)

    Kostanovskiy, A.; Kostanovskaya, M.; Zeodinov, M.; Pronkin, A.

    2017-11-01

    We present the experimental investigation of the relative elongation and the coefficient of linear thermal expansion for monocrystaline alumina Al2O3 (1200 K – 1860 K), zirconia ZrO2 (1200 K – 2730 K) and siliconized silicon carbide SiC+Si (1150 K – 2500 K) in the specified range of temperatures. The following approach is used to measure the relative elongation: the through-cylindrical-marks located in the centre of isothermal part of the sample, and the measurement of temperature by two blackbody models, taken out of the area of the sample where the relative elongation is measured.

  12. Non-contact Creep Resistance Measurement for Ultra-High Temperature Materials

    Science.gov (United States)

    Lee, J.; Bradshaw, C.; Rogers, J. R.; Rathz, T. J.; Wall, J. J.; Choo, H.; Liaw, P. K.; Hyers, R. W.

    2005-01-01

    Conventional techniques for measuring creep are limited to about 1700 C, so a new technique is required for higher temperatures. This technique is based on electrostatic levitation (ESL) of a spherical sample, which is rotated quickly enough to cause creep deformation by centrifugal acceleration. Creep of samples has been demonstrated at up to 2300 C in the ESL facility at NASA MSFC, while ESL itself has been applied at over 3000 C, and has no theoretical maximum temperature. The preliminary results and future directions of this NASA-funded research collaboration will be presented.

  13. Applications of High Throughput (Combinatorial) Methodologies to Electronic, Magnetic, Optical, and Energy-Related Materials

    Science.gov (United States)

    2013-06-17

    American Physical Society. FIG. 28. Structural-magnetic-electronic properties of a La1xSrxMnO3 CCS library as a function of x. (a) A concurrent XRD... tandem with TEM to study hydrogenation in Mg-Ni libraries.319 They found that over a broad range of Ni concentrations, a Ni stabilized fcc Mg phase...the order of the diameter of the capil- lary) investigations of the product phases during electro- chemical catalysis , was devised.375 In this

  14. State of the art on high temperature thermal energy storage for power generation. Part 1. Concepts, materials and modellization

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Antoni; Medrano, Marc; Martorell, Ingrid; Cabeza, Luisa F. [GREA Innovacio Concurrent, Universitat de Lleida, Pere de Cabrera s/n, 25001-Lleida (Spain); Lazaro, Ana; Dolado, Pablo; Zalba, Belen [Instituto de Investigacion en Ingenieria de Aragon, I3A, Grupo de Ingenieria Termica y Sistemas Energeticos (GITSE), Dpto. Ingenieria Mecanica, Area de Maquinas y Motores Termicos, Universidad de Zaragoza, Campus Politecnico Rio Ebro, Edificio ' Agustin de Betancourt' , Maria de Luna s/n, 50018 Zaragoza (Spain)

    2010-01-15

    Concentrated solar thermal power generation is becoming a very attractive renewable energy production system among all the different renewable options, as it has have a better potential for dispatchability. This dispatchability is inevitably linked with an efficient and cost-effective thermal storage system. Thus, of all components, thermal storage is a key one. However, it is also one of the less developed. Only a few plants in the world have tested high temperature thermal energy storage systems. In this paper, the different storage concepts are reviewed and classified. All materials considered in literature or plants are listed. And finally, modellization of such systems is reviewed. (author)

  15. High Temperature Materials Laboratory Fourteenth Annual Report: October 2000 through September 2001

    Energy Technology Data Exchange (ETDEWEB)

    Pasto, A.E.

    2002-05-16

    The HTML User Program continued to work with industrial, academic, and governmental users this year, accepting 92 new projects and developing 48 new user agreements. Table 1 presents the breakdown of these statistics. Figure 1 depicts the continued growth in user agreements and user projects. You will note that the total number of HTML proposals has now exceeded 1000. Also, the large number of new agreements bodes well for the future. At the end of the report, we present a list of proposals to the HTML and a list of agreements between HTML and universities and industries, broken down by state. Program highlights this year included several outstanding user projects (some of which are highlighted in later sections), the annual meeting of the HTML Programs Senior Advisory Committee, and approval by ORNL for the construction of a building to house our new aberration-corrected electron microscope (ACEM) and several other sensitive electron and optical instruments.

  16. Realization of High-temperature Superconductivity in Nano-carbon Materials and Its Application

    Science.gov (United States)

    2015-07-13

    in peer-reviewed journals, 1. T. Hashimoto , S. Kamikawa, J. Haruyama, D. Soriano, J. G. Pedersen, S. Roche “Tunneling magnetoresistance phenomena...Singapore 2014/10/21) ISBN-10: 9814303305 4. T. Hashimoto , S. Kamikawa, Y. Yagi, J. Haruyama, “Electronic Properties of Nanopore Edges of...narrow graphene nanoribbons”, Nanomaterials and Nanotechnology 4:12 | doi: 10.5772/58466 (2014) 6. T. Hashimoto , S. Kamikawa, Y. Yagi, J. Haruyama

  17. High-Temperature Electrochemical Performance of FeF3/C Nanocomposite as a Cathode Material for Lithium-Ion Batteries

    Science.gov (United States)

    Tang, Mengyun; Zhang, Zhengfu; Wang, Zi; Liu, Jingfeng; Yan, Hongge; Peng, Jinhui

    2018-01-01

    Iron trifluoride has been studied as a cathode material due to its cost-effectiveness, low toxicity, and high theoretical capacities of 712 mA h g-1. However, FeF3 has serious shortcomings of poor electronic conductivity and a slow diffusion rate of lithium ions, leading to a lower reversible specific capacity. In this work, FeF3/C nanocomposite has been synthesized successfully via a high-energy ball-milling method, and acetylene black is used as the conductive agent to improve the conductivity of FeF3. The FeF3/C nanocomposite shows a high initial discharge capacity of 346.25 and 161.58 mA h g-1 after 40th cycle at 50 mA g-1. It exhibits good cycle performance and rate performance. The high-temperature discharge capacities decreased with increase in the temperature. The initial high-temperature discharge capacities are found to be 254.17, 300.01, 281.25 and 125.16, and 216.875, 156, 141.67, 150, and 64.98 mA h g-1 at 20th cycles at the 40, 50, 60, and 70 °C, respectively.

  18. Materials Cartography: Representing and Mining Material Space Using Structural and Electronic Fingerprints

    Science.gov (United States)

    Oses, Corey; Isayev, Olexandr; Fourches, Denis; Muratov, Eugene; Rasch, Kevin; Tropsha, Alexander; Curtarolo, Stefano; CenterMaterials Genomics, Duke University Collaboration; LaboratoryMolecular Modeling, UNC Chapel Hill Collaboration

    2015-03-01

    As the proliferation of high-throughput approaches in materials science is increasing the wealth of data in the field, the gap between accumulated-information and derived-knowledge widens. We address the issue of scientific discovery in materials databases by introducing novel analytical approaches based on structural and electronic materials fingerprints. The framework is employed to (i) query large databases of materials using similarity concepts, (ii) map the connectivity of the materials space (i.e., as a materials cartogram) for rapidly identifying regions with unique organizations/properties, and (iii) develop predictive Quantitative Materials Structure-Property Relationships (QMSPR) models for guiding materials design. In this study, we test these fingerprints by seeking target material properties. As a quantitative example, we model the critical temperatures of known superconductors. Our novel materials fingerprinting and materials cartography approaches contribute to the emerging field of materials informatics by enabling effective computational tools to analyze, visualize, model, and design new materials.

  19. Functionalisation of mesoporous materials for application as additives in high temperature PEM fuel cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Sharifi, Monir

    2012-03-06

    The presented thesis contains six original research articles dedicated to the preparation and characterization of organic-inorganic mesoporous materials as additives for polymer electroly1e membrane fuel cells (PEMFCs). The mesoporous materials Si-MCM-41 and benzene-PMO (periodic mesoporous organosilica) were chosen for the investigations. These materials were modified with functional groups for enhanced proton conductivity and water-keeping properties. In order to improve these materials Broenstedt acidic groups were introduced in the framework of mesoporous Si-MCM-41. Therefore, some silicium atoms in the framework were substituted by aluminium using different aluminium sources. Here NaAlO{sub 2} exhibits clearly the best results because the entire aluminium incorporated within the framework is tetragonally coordinated as observed by {sup 2}7AI MAS NMR. The increase of the proton conductivities results from an improved hydrophilicity, a decreased particle size, and newly introduced Broenstedt acidity in the mesoporous Al-MCM-41. However, mesoporous Si-MCM-41 materials functionalised by co-condensation with sulphonic acid groups exhibit the best results concerning proton conductivity, compared to those prepared by grafting. Hence, these materials where characterized in more detail by SANS and by MAS NMR measurements. The first one indicated that by co-condensation the entire inner pore surface is altered by functional groups which are, thus, distributed much more homogeneously than samples functionalised by grafting. This result explains the improved proton conductivities. Additionally, {sup 2}9Si NMR spectra proved that samples prepared by co-condensation lead to a successful and almost complete incorporation of mercaptopropyltrimethoxysilan (MPMS) into the mesoporous framework. Furthermore, it was shown by {sup 1}3C MAS NMR spectroscopy that the majority of the organic functional groups remained intact after H{sub 2}0{sub 2}-oxidation. However, proton

  20. Temperature-Dependent Electron-Electron Interaction in Graphene on SrTiO3.

    Science.gov (United States)

    Ryu, Hyejin; Hwang, Jinwoong; Wang, Debin; Disa, Ankit S; Denlinger, Jonathan; Zhang, Yuegang; Mo, Sung-Kwan; Hwang, Choongyu; Lanzara, Alessandra

    2017-10-11

    The electron band structure of graphene on SrTiO3 substrate has been investigated as a function of temperature. The high-resolution angle-resolved photoemission study reveals that the spectral width at Fermi energy and the Fermi velocity of graphene on SrTiO3 are comparable to those of graphene on a BN substrate. Near the charge neutrality, the energy-momentum dispersion of graphene exhibits a strong deviation from the well-known linearity, which is magnified as temperature decreases. Such modification resembles the characteristics of enhanced electron-electron interaction. Our results not only suggest that SrTiO3 can be a plausible candidate as a substrate material for applications in graphene-based electronics but also provide a possible route toward the realization of a new type of strongly correlated electron phases in the prototypical two-dimensional system via the manipulation of temperature and a proper choice of dielectric substrates.

  1. Synthesis and Processing of Ultra-High Temperature Metal Carbide and Metal Diboride Nanocomposite Materials

    Science.gov (United States)

    2008-04-15

    been used to produce metal carbides, including phenolic resins, furfuryl alcohol, sugar, corn starch , petroleum pitch, polyacrylonitrile (PAN) polymers...carboxylates. Metal-organic compounds are usually subjected to hydrolysis and condensa- tion reactions to produce polymeric or colloidal metal-oxide...prior to solvent removal. The hydrolysis time, temperature, and atmosphere can be altered to control the grain size and phase distribu- tion in the

  2. New dielectric material for low temperature thermometry in high magnetic fields

    NARCIS (Netherlands)

    Maior, M.M.; Molnar, S.B.; Vysochanskii, Yu.M.; Gurzan, M.I.; Loosdrecht, P.H.M. van; Linden, P.J.E.M. van der; Kempen, H. van

    1993-01-01

    Dielectric experiments on the incommensurate solid solution (Pb0.45Sn0.55)2P2Se6 for T=1.2-200 K reveal a strong temperature dependence of the real part of the dielectric constant for T<45 K. The relative dielectric sensitivity d ln(ε’)/dT≈2-8 K-1 is found to be 2-3 times higher in comparison to

  3. Optical Fiber Chemical Sensor with Sol-Gel Derived Refractive Material as Transducer for High Temperature Gas Sensing in Clean Coal Technology

    Energy Technology Data Exchange (ETDEWEB)

    Shiquan Tao

    2006-12-31

    The chemistry of sol-gel derived silica and refractive metal oxide has been systematically studied. Sol-gel processes have been developed for preparing porous silica and semiconductor metal oxide materials. Micelle/reversed micelle techniques have been developed for preparing nanometer sized semiconductor metal oxides and noble metal particles. Techniques for doping metal ions, metal oxides and nanosized metal particles into porous sol-gel material have also been developed. Optical properties of sol-gel derived materials in ambient and high temperature gases have been studied by using fiber optic spectroscopic techniques, such as fiber optic ultraviolet/visible absorption spectrometry, fiber optic near infrared absorption spectrometry and fiber optic fluorescence spectrometry. Fiber optic spectrometric techniques have been developed for investigating the optical properties of these sol-gel derived materials prepared as porous optical fibers or as coatings on the surface of silica optical fibers. Optical and electron microscopic techniques have been used to observe the microstructure, such as pore size, pore shape, sensing agent distribution, of sol-gel derived material, as well as the size and morphology of nanometer metal particle doped in sol-gel derived porous silica, the nature of coating of sol-gel derived materials on silica optical fiber surface. In addition, the chemical reactions of metal ion, nanostructured semiconductor metal oxides and nanometer sized metal particles with gas components at room temperature and high temperatures have also been investigated with fiber optic spectrometric methods. Three classes of fiber optic sensors have been developed based on the thorough investigation of sol-gel chemistry and sol-gel derived materials. The first group of fiber optic sensors uses porous silica optical fibers doped with metal ions or metal oxide as transducers for sensing trace NH{sub 3} and H{sub 2}S in high temperature gas samples. The second group of

  4. Thermo-Mechanical and Thermal behavior of High-Temperature Structural Materials.

    Science.gov (United States)

    1982-12-31

    reached a value at which in many candidate materials, such as tar-bonded magnesite refractories , substantial soften- L. ing and creep may occur. If so...number) Thermal shock, thermal stress, thermal diffusivity, thermal conductivity; refractories , composites, radiation heat transfer, cyclic heating...Bentsen and D. P. H. Hasselman, "The Measurement of the Thermal Conductivity of Refractories by the Laser-Flash Method." IV J. R. Thomas, J. I

  5. SPECTROSCOPIC DIAGNOSIS IN ELECTRONIC TEMPERATURE ...

    African Journals Online (AJOL)

    ABSTRACT. In this work, we are interested in the diagnostics in electronic temperature of a plasma purely photoionized, based on the intensity ration of lines emitted by ions helium-like, which have an atomic number Z relatively small. We considered the three lines corresponding to the transitions starting from the excited ...

  6. Electron-trapping polycrystalline materials with negative electron affinity.

    Science.gov (United States)

    McKenna, Keith P; Shluger, Alexander L

    2008-11-01

    The trapping of electrons by grain boundaries in semiconducting and insulating materials is important for a wide range of physical problems, for example, relating to: electroceramic materials with applications as sensors, varistors and fuel cells, reliability issues for solar cell and semiconductor technologies and electromagnetic seismic phenomena in the Earth's crust. Surprisingly, considering their relevance for applications and abundance in the environment, there have been few experimental or theoretical studies of the electron trapping properties of grain boundaries in highly ionic materials such as the alkaline earth metal oxides and alkali halides. Here we demonstrate, by first-principles calculations on MgO, LiF and NaCl, a qualitatively new type of electron trapping at grain boundaries. This trapping is associated with the negative electron affinity of these materials and is unusual as the electron is confined in the empty space inside the dislocation cores.

  7. Temperature and Material Flow Prediction in Friction-Stir Spot Welding of Advanced High-Strength Steel

    Energy Technology Data Exchange (ETDEWEB)

    Miles, Michael; Karki, U.; Hovanski, Yuri

    2014-10-01

    Friction-stir spot welding (FSSW) has been shown to be capable of joining advanced high-strength steel, with its flexibility in controlling the heat of welding and the resulting microstructure of the joint. This makes FSSW a potential alternative to resistance spot welding if tool life is sufficiently high, and if machine spindle loads are sufficiently low that the process can be implemented on an industrial robot. Robots for spot welding can typically sustain vertical loads of about 8 kN, but FSSW at tool speeds of less than 3000 rpm cause loads that are too high, in the range of 11–14 kN. Therefore, in the current work, tool speeds of 5000 rpm were employed to generate heat more quickly and to reduce welding loads to acceptable levels. Si3N4 tools were used for the welding experiments on 1.2-mm DP 980 steel. The FSSW process was modeled with a finite element approach using the Forge* software. An updated Lagrangian scheme with explicit time integration was employed to predict the flow of the sheet material, subjected to boundary conditions of a rotating tool and a fixed backing plate. Material flow was calculated from a velocity field that is two-dimensional, but heat generated by friction was computed by a novel approach, where the rotational velocity component imparted to the sheet by the tool surface was included in the thermal boundary conditions. An isotropic, viscoplastic Norton-Hoff law was used to compute the material flow stress as a function of strain, strain rate, and temperature. The model predicted welding temperatures to within percent, and the position of the joint interface to within 10 percent, of the experimental results.

  8. Temperature and Material Flow Prediction in Friction-Stir Spot Welding of Advanced High-Strength Steel

    Science.gov (United States)

    Miles, M.; Karki, U.; Hovanski, Y.

    2014-10-01

    Friction-stir spot welding (FSSW) has been shown to be capable of joining advanced high-strength steel, with its flexibility in controlling the heat of welding and the resulting microstructure of the joint. This makes FSSW a potential alternative to resistance spot welding if tool life is sufficiently high, and if machine spindle loads are sufficiently low that the process can be implemented on an industrial robot. Robots for spot welding can typically sustain vertical loads of about 8 kN, but FSSW at tool speeds of less than 3000 rpm cause loads that are too high, in the range of 11-14 kN. Therefore, in the current work, tool speeds of 5000 rpm were employed to generate heat more quickly and to reduce welding loads to acceptable levels. Si3N4 tools were used for the welding experiments on 1.2-mm DP 980 steel. The FSSW process was modeled with a finite element approach using the Forge® software. An updated Lagrangian scheme with explicit time integration was employed to predict the flow of the sheet material, subjected to boundary conditions of a rotating tool and a fixed backing plate. Material flow was calculated from a velocity field that is two-dimensional, but heat generated by friction was computed by a novel approach, where the rotational velocity component imparted to the sheet by the tool surface was included in the thermal boundary conditions. An isotropic, viscoplastic Norton-Hoff law was used to compute the material flow stress as a function of strain, strain rate, and temperature. The model predicted welding temperatures to within 4%, and the position of the joint interface to within 10%, of the experimental results.

  9. Optical cell for combinatorial in situ Raman spectroscopic measurements of hydrogen storage materials at high pressures and temperatures.

    Science.gov (United States)

    Hattrick-Simpers, Jason R; Hurst, Wilbur S; Srinivasan, Sesha S; Maslar, James E

    2011-03-01

    An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storage materials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element lenses. For combinatorial investigations, up to 19 individual powder samples can be loaded into the optical cell at one time. This cell design is also compatible with thin-film samples. To demonstrate the capabilities of the cell, in situ measurements of the Ca(BH(4))(2) and nano-LiBH(4)-LiNH(2)-MgH(2) hydrogen storage systems at elevated temperatures and pressures are reported.

  10. Optical cell for combinatorial in situ Raman spectroscopic measurements of hydrogen storage materials at high pressures and temperatures

    Science.gov (United States)

    Hattrick-Simpers, Jason R.; Hurst, Wilbur S.; Srinivasan, Sesha S.; Maslar, James E.

    2011-03-01

    An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storage materials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element lenses. For combinatorial investigations, up to 19 individual powder samples can be loaded into the optical cell at one time. This cell design is also compatible with thin-film samples. To demonstrate the capabilities of the cell, in situ measurements of the Ca(BH4)2 and nano-LiBH4-LiNH2-MgH2 hydrogen storage systems at elevated temperatures and pressures are reported.

  11. High Temperature Electrostrictive Ceramics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop high temperature electrostrictors from bismuth-based ferroelectrics. These materials will exhibit high strain and low loss in...

  12. Equipment for Solid State Stir Welding of High Temperature Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Stir welding generates high-quality joints in fabricated structure and is the baseline joining process for most NASA aluminum alloy structures such as cryogenic...

  13. Fundamental Understanding of Ambient and High-Temperature Plasticity Phenomena in Structural Materials in Advanced Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Deo, Chaitanya; Zhu, Ting; McDowell, David

    2013-11-17

    The goal of this research project is to develop the methods and tools necessary to link unit processes analyzed using atomistic simulations involving interaction of vacancies and interstitials with dislocations, as well as dislocation mediation at sessile junctions and interfaces as affected by radiation, with cooperative influence on higher-length scale behavior of polycrystals. These tools and methods are necessary to design and enhance radiation-induced damage-tolerant alloys. The project will achieve this goal by applying atomistic simulations to characterize unit processes of: 1. Dislocation nucleation, absorption, and desorption at interfaces 2. Vacancy production, radiation-induced segregation of substitutional Cr at defect clusters (point defect sinks) in BCC Fe-Cr ferritic/martensitic steels 3. Investigation of interaction of interstitials and vacancies with impurities (V, Nb, Ta, Mo, W, Al, Si, P, S) 4. Time evolution of swelling (cluster growth) phenomena of irradiated materials 5. Energetics and kinetics of dislocation bypass of defects formed by interstitial clustering and formation of prismatic loops, informing statistical models of continuum character with regard to processes of dislocation glide, vacancy agglomeration and swelling, climb and cross slip This project will consider the Fe, Fe-C, and Fe-Cr ferritic/martensitic material system, accounting for magnetism by choosing appropriate interatomic potentials and validating with first principles calculations. For these alloys, the rate of swelling and creep enhancement is considerably lower than that of face-centered cubic (FCC) alloys and of austenitic Fe-Cr-Mo alloys. The team will confirm mechanisms, validate simulations at various time and length scales, and improve the veracity of computational models. The proposed research?s feasibility is supported by recent modeling of radiation effects in metals and alloys, interfacial dislocation transfer reactions in nano-twinned copper, and dislocation

  14. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  15. Room temperature formation of high-mobility two-dimensional electron gases at crystalline complex oxide interfaces

    DEFF Research Database (Denmark)

    Chen, Yunzhong; Bovet, N.; Kasama, Takeshi

    2014-01-01

    Well-controlled sub-unit-cell layer-bylayer epitaxial growth of spinel alumina is achieved at room temperature on a TiO2-terminated SrTiO3 single-crystalline substrate. By tailoring the interface redox reaction, 2D electron gases with mobilities exceeding 3000 cm 2 V−1 s−1 are achieved...

  16. Evaluation of High-temperature Physicochemical Interactions Between the H282Alloy Melt and Ceramic Material of the Crucible

    Directory of Open Access Journals (Sweden)

    Pirowski Z.

    2014-12-01

    Full Text Available Nickel alloys belong to the group of most resistant materials when used under the extreme operating conditions, including chemically aggressive environment, high temperature, and high loads applied over a long period of time. Although in the global technology market one can find several standard cast nickel alloys, the vast majority of components operating in machines and equipment are made from alloys processed by the costly metalworking operations. Analysis of the available literature and own studies have shown that the use of casting technology in the manufacture of components from nickel alloys poses a lot of difficulty. This is due to the adverse technological properties of these alloys, like poor fluidity, high casting shrinkage, and above all, high reactivity of liquid metal with the atmospheric air over the bath and with the ceramic material of both the crucible and foundry mold. The scale of these problems increases with the expected growth of performance properties which these alloys should offer to the user.

  17. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

    Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  18. Effects of pre-irradiation annealing at high temperature on optical absorption and electron paramagnetic resonance of natural pumpellyite mineral

    Energy Technology Data Exchange (ETDEWEB)

    Javier-Ccallata, Henry, E-mail: henrysjc@gmail.com [Escuela de Ingeniería Electrónica y Telecomunicaciones, Universidad Alas Peruanas Filial Arequipa, Urb. D. A. Carrión G-14, J. L. Bustamante y Rivero, Arequipa (Peru); Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Filho, Luiz Tomaz [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil); Faculdade de Tecnologia e Ciências Exatas, Universidade São Judas Tadeu, Rua Taquari 546, São Paulo, SP (Brazil); Sartorelli, Maria L. [Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Watanabe, Shigueo [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil)

    2013-09-15

    Highlights: •Natural pumpellyite mineral presents superposition bands around 900 and 1060 nm due Fe{sup 2+}and Fe{sup 3+}. •High temperature annealing influences the EPR and OA spectra. •The behavior of EPR line for 800 and 900 °C can be attributed to forbidden dd transitions due the Fe{sup 3+}. -- Abstract: Natural silicate mineral of pumpellyite, Ca{sub 2}MgAl{sub 2}(SiO{sub 4})(Si{sub 2}O{sub 7})(OH){sub 2}·(H{sub 2}O), point group A2/m, has been studied concerning high temperature annealing and γ-radiation effects on Optical Absorption (OA) and Electron Paramagnetic Resonance (EPR) properties. Chemical analysis revealed that besides Si, Al, Ca and Mg, other oxides i.e., Fe, Mn, Na, K, Ti and P are present in the structure as impurities. OA measurements of natural and annealed pumpellyite revealed several bands in the visible region due to spin forbidden transitions of Fe{sup 2+} and Fe{sup 3+}. The behaviour of bands around 900 and 1060 nm, with pre-annealing and γ radiation dose, indicating a transition Fe{sup 2+} → e{sup −} + Fe{sup 3+}. On the other hand, EPR measurements reveal six lines of Mn{sup 2+}, and satellites due to hyperfine interaction, superimposed on the signal of Fe{sup 3+} around of g = 2. For heat treatment from 800 °C the signal grows significantly and for 900 °C a strong signal of Fe{sup 3+} hides all Mn{sup 2+} lines. The strong growth of this signal indicates that the transitions are due to Fe{sup 3+} dipole–dipole interactions.

  19. High Temperature Electronic and Thermal Transport Properties of EuGa2- x In x Sb2

    Science.gov (United States)

    Chanakian, Sevan; Weber, Rochelle; Aydemir, Umut; Ormeci, Alim; Fleurial, Jean-Pierre; Bux, Sabah; Snyder, G. Jeffrey

    2017-08-01

    The Zintl phase EuGa2Sb2 was synthesized via ball milling followed by hot pressing. The crystal structure of EuGa2Sb2 is comprised of a 3-D network of polyanionic [Ga2Sb2]2- tunnels filled with Eu cations that provide charge balance (Eu2+[Ga2Sb2]2-). Here we report the temperature-dependent resistivity, Hall Effect, Seebeck coefficient and thermal conductivity for EuGa2- x In x Sb2 ( x = 0, 0.05, 0.1) from 300 K to 775 K. Experimental results demonstrate that the material is a p-type semiconductor. However, a small band gap (˜0.1 eV) prevents EuGa2Sb2 from having high zT at higher temperatures. Isoelectronic substitution of In on the Ga site leads to point defect scattering of holes and phonons, thus reducing thermal conductivity and resulting in a slight improvement in zT.

  20. Materials for low-temperature fuel cells

    CERN Document Server

    Ladewig, Bradley; Yan, Yushan; Lu, Max

    2014-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in Low-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in low-temperature fuel cells. A related book will cover key materials in high-temperature fuel cells. The two books form part

  1. Simulation of the electron collection efficiency of a PMT based on the MCP coated with high secondary yield material

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lin, E-mail: chenlin@opt.cn [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi' an 710119 (China); Graduate School of Chinese Academy of Sciences (CAS), Beijing 100049 (China); Xi' an Jiaotong University, Xi' an 710049 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006 (China); Tian, Jinshou [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi' an 710119 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006 (China); Zhao, Tianchi [Institute of High Energy Physics (IHEP) of CAS, Beijing 100049 (China); Liu, Chunliang [Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Hulin; Wei, Yonglin; Sai, Xiaofeng [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi' an 710119 (China); Chen, Ping [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi' an 710119 (China); Graduate School of Chinese Academy of Sciences (CAS), Beijing 100049 (China); Wang, Xing; Lu, Yu [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi' an 710119 (China); Hui, Dandan [State Key Laboratory of Transient Optics and Photonics, Xi' an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi' an 710119 (China); Graduate School of Chinese Academy of Sciences (CAS), Beijing 100049 (China)

    2016-11-01

    Owning to the serious loss of photoelectrons striking at the input electrode of traditional microchannel plate (MCP), photoelectron collection efficiency (CE) of photomultiplier tubes based on MCP (MCP-PMTs) fluctuates around the MCP open area fraction and cannot make a breakthrough. Depositing a thin film of high secondary electron yield material on the MCP is proposed as an effective approach to improve the CE. The available simulation and experimental data to validate it, however, is sparse. In our work, a three-dimensional small area MCP model is developed in CST Studio Suite to evaluate the collection efficiencies of PMTs based on the traditional MCP and the coated one, respectively. Results predict that CE of the PMT based on the coated MCP has a significant increase and a better uniformity, which is expected to reach 100%.

  2. TAOI B- Computational Microstructural Optimization Design Tool for High Temperature Structural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Rajiv [Univ. Of North Texas, Denton, TX (United States); Charit, Indrajit [Univ. of Idaho, Moscow, ID (United States)

    2015-02-28

    The objectives of this research were two-fold: (a) develop a methodology for microstructural optimization of alloys - genetic algorithm approach for alloy microstructural optimization using theoretical models based on fundamental micro-mechanisms, and (b) develop a new computationally designed Ni-Cr alloy for coal-fired power plant applications. The broader outcome of these objectives is expected to be creation of an integrated approach for ‘structural materials by microstructural design’. Three alloy systems were considered for computational optimization and validation, (i) Ni-20Cr (wt.%) base alloy using only solid solution strengthening, (ii) nano-Y2O3 containing Ni-20Cr-1.2Y2O3 (wt.%) alloy for dispersion strengthening and (iii) a sub-micron Al2O3 for composite strengthening, Ni-20Cr-1.2Y2O3-5.0Al2O3 (wt.%). The specimens were synthesized by mechanical alloying and consolidated using spark plasma sintering. Detailed microstructural characterization was done along with initial mechanical properties to validate the computational prediction. A key target property is to have creep rate of 1x10-9 s-1 at 100 MPa and 800oC. The initial results were quite promising and require additional quantification of strengthening contributions from dislocation-particle attractive interaction and load transfer. The observed creep rate was in order of 10-9 s-1 for longer time creep test of Ni-20Cr -1.2Y2O3-5Al2O3, lending support to the overall approach pursued in this project.

  3. Advances in high temperature chemistry

    CERN Document Server

    Eyring, Leroy

    1969-01-01

    Advances in High Temperature Chemistry, Volume 2 covers the advances in the knowledge of the high temperature behavior of materials and the complex and unfamiliar characteristics of matter at high temperature. The book discusses the dissociation energies and free energy functions of gaseous monoxides; the matrix-isolation technique applied to high temperature molecules; and the main features, the techniques for the production, detection, and diagnosis, and the applications of molecular beams in high temperatures. The text also describes the chemical research in streaming thermal plasmas, as w

  4. Material Properties at Low Temperature

    CERN Document Server

    Duthil, P

    2014-07-17

    From ambient down to cryogenic temperatures, the behaviour of materials changes greatly. Mechanisms leading to variations in electrical, thermal, mechanical, and magnetic properties in pure metals, alloys, and insulators are briefly introduced from a general engineering standpoint. Data sets are provided for materials commonly used in cryogenic systems for design purposes.

  5. Advanced Materials and Processes for High Energy Resolution Room Temperature Gamma Ray Spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Douglas S. McGregor

    2007-12-12

    A significant amount of progress has been achieved in the development of the novel vacuum distillation method described in the proposal. The process for the purification of Te was fully developed and characterized in a series of trials. The purification effect was confirmed with GDMS sample analysis and indicates the process yields very high purity Te metal. Results of this initial process study have been submitted for publication in the Proceedings of the SPIE and will be presented on August 28, 2007 at the SPIE Optics and Photonics 2007 conference in San Diego, CA. Concurrent to the development of the Te process, processes for the purification of Cd, Zn, and Mn have also progressed. The development of the processes for Cd and Zn are nearly complete, while the development of the process for Mn is still in its infancy. It is expected that a full characterization of the Cd process will be completed within the next quarter, followed by Zn. Parallel to those characterization studies, efforts will be made to further develop the Mn purification process. Zone melting work for Te and Cd has also been efforted as per the project work schedule. Initial trials have been completed and the processes developed. Characterization of the results will be completed within the first fiscal year. Finally, an apparatus for the zone refinement of Cd, Zn, and Mn has been constructed and initial trials are set to begin shortly.

  6. Oxidation of TaSi2-Containing ZrB2-SiC Ultra-High Temperature Materials

    Science.gov (United States)

    Opila, Elizabeth J.; Smith, Jim; Levine, Stanley R.; Lorincz, Jonathan; Reigel, Marissa

    2010-01-01

    Hot pressed coupons of composition ZrB2-20 v% SiC-5 v% TaSi2 and ZrB2-20 v% SiC-20 v% TaSi2 were oxidized in stagnant air at temperatures of 1627 and 1927C for one, five and ten 10-minute cycles. The oxidation reactions were characterized by weight change kinetics, x-ray diffraction, and SEM/EDS. Detailed WDS/microprobe quantitative analyses of the oxidation products were conducted for the ZrB2-20 v% SiC-20 v% TaSi2 sample oxidized for five 10-minute cycles at 1927C. Oxidation kinetics and product formation were compared to ZrB2-20 v% SiC with no TaSi2 additions. It was found that the 20 v% TaSi2 composition exhibited improved oxidation resistance relative to the material with no TaSi2 additions at 1627C. However, for exposures at 1927C less oxidation resistance and extensive liquid phase formation were observed compared to the material with no TaSi2 additions. Attempts to limit the liquid phase formation by reducing the TaSi2 content to 5 v% were unsuccessful. In addition, the enhanced oxidation resistance at 1627C due to 20 v% TaSi2 additions was not achieved at the 5 v% addition level. The observed oxidation product evolution is discussed in terms of thermodynamics and phase equilibria for the TaSi2-containing ZrB2-SiC material system. TaSi2-additions to ZrB2-SiC at any level are not recommended for ultra-high temperature (>1900C) applications due to excessive liquid phase formation.

  7. High-performance double-filter soft x-ray diagnostic for measurement of electron temperature structure and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    McGarry, M. B.; Den Hartog, D. J.; Goetz, J. A.; Thomas, M. A.; Reyfman, M.; Kumar, S. T. A. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Franz, P. [Consorzio RFX, Associazione Euratom-ENEA per la Fusione, Padova (Italy)

    2012-10-15

    A new soft x-ray (SXR) T{sub e} and tomography diagnostic has been developed for MST that can be used for simultaneous SXR spectrum measurement, tomographically reconstructed emissivity, and reconstructed and line-of-sight electron temperature. The diagnostic utilizes high-performance differential transimpedance amplifiers (gain 10{sup 5}-10{sup 9}) to provide fast time response (up to 125 kHz), allowing for the study of plasma structure dynamics. SXR double-foil T{sub e} measurements are consistent with Thomson scattering. SXR brightness through a variety of filter thicknesses has been combined with charge exchange recombination spectroscopy (CHERS) impurity density measurements to determine the plasma energy spectrum. Magnetic pickup from the fluctuating magnetic fields in the plasma (B(tilde sign){approx}20 gauss at 10-20 kHz) has been dramatically reduced by improving the detector and housing design, so that nanoampere diode currents are now measured without interference from the substantial fluctuating magnetic field incident on the plasma facing surface of the probe.

  8. Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials

    Energy Technology Data Exchange (ETDEWEB)

    Weber, J. K. R.; Alderman, O. L. G. [Materials Development, Inc., Arlington Heights, Illinois 60004 (United States); Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Tamalonis, A.; Sendelbach, S. [Materials Development, Inc., Arlington Heights, Illinois 60004 (United States); Benmore, C. J. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Hebden, A.; Williamson, M. A. [Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2016-07-15

    An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.

  9. Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials.

    Science.gov (United States)

    Weber, J K R; Tamalonis, A; Benmore, C J; Alderman, O L G; Sendelbach, S; Hebden, A; Williamson, M A

    2016-07-01

    An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.

  10. Tokamak Plasmas: Electron temperature $(T_ {e}) $ measurements ...

    Indian Academy of Sciences (India)

    Thomson scattering technique based on high power laser has already proved its superoirity in measuring the electron temperature (e) and density (e) in fusion plasma devices like tokamaks. The method is a direct and unambiguous one, widely used for the localised and simultaneous measurements of the above ...

  11. Polymer electronic devices and materials.

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, William Kent; Baca, Paul Martin; Dirk, Shawn M.; Anderson, G. Ronald; Wheeler, David Roger

    2006-01-01

    Polymer electronic devices and materials have vast potential for future microsystems and could have many advantages over conventional inorganic semiconductor based systems, including ease of manufacturing, cost, weight, flexibility, and the ability to integrate a wide variety of functions on a single platform. Starting materials and substrates are relatively inexpensive and amenable to mass manufacturing methods. This project attempted to plant the seeds for a new core competency in polymer electronics at Sandia National Laboratories. As part of this effort a wide variety of polymer components and devices, ranging from simple resistors to infrared sensitive devices, were fabricated and characterized. Ink jet printing capabilities were established. In addition to promising results on prototype devices the project highlighted the directions where future investments must be made to establish a viable polymer electronics competency.

  12. Structure and Properties of High-Temperature Multilayer Hybrid Material Based on Vanadium Alloy and Stainless Steel

    Science.gov (United States)

    Nechaykina, Tatyana A.; Nikulin, Sergey A.; Rozhnov, Andrey B.; Khatkevich, Vladimir M.; Rogachev, Stanislav O.

    2017-03-01

    The present work is devoted to the development of new structural composite material having the unique complex of properties for operating in ultrahard conditions that combine high temperatures, radiation, and aggressive environments. A new three-layer composite tube material based on vanadium alloy (V-4Ti-4Cr) protected by stainless steel (Fe-0.2C-13Cr) has been obtained by co-extrusion. Mechanism and kinetics of formation as well as structure, composition, and mechanical properties of "transition" area between vanadium alloy and stainless steel have been studied. The transition area (13- to 22- µm thick) of the diffusion interaction between vanadium alloy and steel was formed after co-extrusion. The microstructure in the transition area was rather complicated comprising different grain sizes in components, but having no defects or brittle phases. Tensile strength of the composite was an average 493 ± 22 MPa, and the elongation was 26 ± 3 pct. Annealing at 1073 K (800 °C) increased the thickness of transition area up to 1.2 times, homogenized microstructure, and slightly changed mechanical properties. Annealing at 1273 K (1000 °C) further increased the thickness of transition area and also lead to intensive grain growth in steel and sometimes to separation between composite components during tensile tests. Annealing at 1073 K (800 °C) is proposed as appropriate heat treatment after co-extrusion of composite providing balance between diffusion interaction thickness and microstructure and monolithic-like behavior of composite during tensile tests.

  13. Complex permittivity measurements during high temperature recycling of space shuttle antenna window and dielectric heat shield materials

    Science.gov (United States)

    Bassett, H. L.; Bomar, S. H., Jr.

    1973-01-01

    The research performed and the data obtained on candidate space shuttle antenna window and heat shield materials are presented. The measurement technique employs a free-space focused beam microwave bridge for obtaining RF transmission data, and a device which rotates a sample holder which is heated on one side by natural gas-air flames. The surface temperature of each sample is monitored by IR pyrometry; embedded and rear surface thermocouples are also used in obtaining temperature data. The surface of the sample undergoing test is subjected to approximately the same temperature/time profile that occurs at a proposed antenna position on the space shuttle as it re-enters. The samples are cycled through ten of these temperature profiles to determine the recycling effects. Very little change was noted in the materials due to the recycling.

  14. Microstructure and Room Temperature Compressive Deformation Behavior of Cold-Sprayed High-Strength Cu Bulk Material

    Science.gov (United States)

    Kim, Young-Kyun; Kim, Kyu-Sik; Kim, Hyung-Jun; Park, Chan-Hee; Lee, Kee-Ahn

    2017-10-01

    This study investigated the room temperature compressive deformation behavior of Cu bulk material manufactured by cold spray process. Initial microstructural observation identified a unique microstructure with grain size of hundreds of nm in the particle interface area and relatively coarse grains in all other areas. Room temperature compressive results confirmed cold-sprayed Cu to have a yield strength of 340 MPa, which is similar to materials manufactured by severe plastic deformation process such as equal channel angular press. In addition, strain softening phenomenon, which is rarely found in room temperature compressive deformation, was observed. According to such unique characteristics, continuous microstructure evolution and surface fractures according to the strain ( ɛ t = 0.3/0.6/0.9) of the material were observed, and considerations were made for deformation and fracture behavior. Microstructural observation after compressive deformation confirmed that average grain size decreased as the strain increased, and the fraction of the low-angle boundary, which has an indirect relationship with dislocation density, showed a tendency to decrease in ɛ t = 0.3-0.6 region where the strain softening phenomenon occurs. Based on the results described above, this study was able to identify the possibility of manufacturing cold-sprayed Cu bulk material for structural material and its room temperature deformation behavior.

  15. Progress in molecular precursors for electronic materials

    Energy Technology Data Exchange (ETDEWEB)

    Buhro, W.E. [Washington Univ., St. Louis, MO (United States)

    1996-09-01

    Molecular-precursor chemistry provides an essential underpinning to all electronic-materials technologies, including photovoltaics and related areas of direct interest to the DOE. Materials synthesis and processing is a rapidly developing field in which advances in molecular precursors are playing a major role. This article surveys selected recent research examples that define the exciting current directions in molecular-precursor science. These directions include growth of increasingly complex structures and stoichiometries, surface-selective growth, kinetic growth of metastable materials, growth of size-controlled quantum dots and quantum-dot arrays, and growth at progressively lower temperatures. Continued progress in molecular-precursor chemistry will afford precise control over the crystal structures, nanostructures, and microstructures of electronic materials.

  16. Theoretical Studies of Possible Synthetic Routes for the High Energy Density Material Td N4: Excited Electronic States

    Science.gov (United States)

    Lee, Timothy J.; Dateo, Christopher E.

    2001-01-01

    Vertical electronic excitation energies for single states have been computed for the high energy density material (HEDM) Td N4 in order to assess possible synthetic routes that originate from excited electronic states of N2 molecules. Several ab initio theoretical approaches have been used, including complete active space self-consistent field (CASSCF), state averaged CASSCF (SA-CASSCF), singles configuration interaction (CIS), CIS with second-order and third-order correlation corrections [CIS(D)) and CIS(3)], and linear response singles and doubles coupled-cluster (LRCCSD), which is the highest level of theory employed. Standard double zeta polarized (DZP) and triple zeta double polarized (TZ2P) one-particle basis sets were used. The CASSCF calculations are found to overestimate the excitation energies, while the SA-CASSCF approach rectifies this error to some extent, but not completely. The accuracy of the CIS calculations varied depending on the particular state, while the CIS(D), CIS(3), and LRCCSD results are in generally good agreement. Based on the LRCCSD calculations, the lowest six excited singlet states are 9.35(l(sup)T1), 10.01(l(sup)T2), 10.04(1(sup)A2), 10.07(1(sup)E), 10.12(2(sup)T1), and 10.42(2(sup)T2) eV above the ground state, respectively. Comparison of these excited state energies with the energies of possible excited states of N2+N2 fragments, leads us to propose that the most likely synthetic route for Td N4 involving this mechanism arises from combination of two bound quintet states of N2.

  17. Advanced electrical and electronics materials processes and applications

    CERN Document Server

    Gupta, K M

    2015-01-01

    This comprehensive and unique book is intended to cover the vast and fast-growing field of electrical and electronic materials and their engineering in accordance with modern developments.   Basic and pre-requisite information has been included for easy transition to more complex topics. Latest developments in various fields of materials and their sciences/engineering, processing and applications have been included. Latest topics like PLZT, vacuum as insulator, fiber-optics, high temperature superconductors, smart materials, ferromagnetic semiconductors etc. are covered. Illustrations and exa

  18. Determination of electron temperature and electron density in ...

    African Journals Online (AJOL)

    The electron temperatures and electron densities of air and argon have been measured at various pds (pressure times distance). The electron temperatures have been computed using the Johnson-Malter double-probe method. The electron densities have been computed using the total positive ion current and the ...

  19. Review: Potential Strength of Fly Ash-Based Geopolymer Paste with Substitution of Local Waste Materials with High-Temperature Effect

    Science.gov (United States)

    Subekti, S.; Bayuaji, R.; Darmawan, M. S.; Husin, N. A.; Wibowo, B.; Anugraha, B.; Irawan, S.; Dibiantara, D.

    2017-11-01

    This research provided an overview of the potential fly ash based geopolymer paste for application in building construction. Geopolymer paste with various variations of fly ash substitution with local waste material and high-temperature influence exploited with the fresh and hardened condition. The local waste material which utilized for this study were sandblasting waste, carbide waste, shell powder, bagasse ash, rice husk and bottom ash. The findings of this study indicated that fly-based geopolymer paste with local waste material substitution which had high-temperature influence ash showed a similar nature of OPC binders potentially used in civil engineering applications.

  20. Nanoparticle Metamorphosis: An in Situ High-Temperature Transmission Electron Microscopy Study of the Structural Evolution of Heterogeneous Au:Fe 2 O 3 Nanoparticles

    KAUST Repository

    Baumgardner, William J.

    2014-05-27

    High-temperature in situ electron microscopy and X-ray diffraction have revealed that Au and Fe2O3 particles fuse in a fluid fashion at temperatures far below their size-reduced melting points. With increasing temperature, the fused particles undergo a sequence of complex structural transformations from surface alloy to phase segregated and ultimately core-shell structures. The combination of in situ electron microscopy and spectroscopy provides insights into fundamental thermodynamic and kinetic aspects governing the formation of heterogeneous nanostructures. The observed structural transformations present an interesting analogy to thin film growth on the curved surface of a nanoparticle. Using single-particle observations, we constructed a phase diagram illustrating the complex relationships among composition, morphology, temperature, and particle size. © 2014 American Chemical Society.

  1. New experimental device for VHTR structural material testing and helium coolant chemistry investigation - High Temperature Helium Loop in NRI Rez

    Energy Technology Data Exchange (ETDEWEB)

    Berka, Jan, E-mail: bej@cvrez.cz [Research Centre Rez, Ltd, Husinec-Rez 130, 25068 Rez (Czech Republic); Institute of Chemical Technology Prague, Technicka 1905, 16628 Prague 6 (Czech Republic); Matecha, Josef, E-mail: josef.matecha@ujv.cz [Nuclear Research Institute Rez plc., Husinec-Rez 130, 25068 Rez (Czech Republic); Cerny, Michal [Institute of Chemical Technology Prague, Technicka 1905, 16628 Prague 6 (Czech Republic); Viden, Ivan, E-mail: ivan.viden@vscht.cz [Institute of Chemical Technology Prague, Technicka 1905, 16628 Prague 6 (Czech Republic); Sus, Frantisek [Research Centre Rez, Ltd, Husinec-Rez 130, 25068 Rez (Czech Republic); Nuclear Research Institute Rez plc., Husinec-Rez 130, 25068 Rez (Czech Republic); Hajek, Petr [Nuclear Research Institute Rez plc., Husinec-Rez 130, 25068 Rez (Czech Republic)

    2012-10-15

    The High Temperature Helium Loop (HTHL) is an experimental device for simulation of VHTR helium coolant conditions. The purpose of the HTHL is structural materials testing and helium coolant chemistry investigation. In the HTHL pure helium will be used as working medium and its main physical parameters are 7 MPa, max. temperature in the test section 900 Degree-Sign C and flow rate 37.8 kg/h. The HTHL consists of an active channel, the helium purification system, the system of impurities dosage (e.g. CO, CO{sub 2}, H{sub 2}, H{sub 2}O, O{sub 2}, N{sub 2}, and CH{sub 4}) and the helium chemistry monitoring system (sampling and on-line analysis and determination of impurities in the helium flow). The active channel is planned to be placed into the core of the experimental reactor LVR-15 which will serve as a neutron flux source (max. 2.5 Multiplication-Sign 10{sup 18} n/m{sup 2} s for fast neutrons). The HTHL is now under construction. Some of its main parts are finished, some are still being produced (active channel internals, etc.), some should be improved to work correctly (the helium circulatory compressor); certain sub-systems are planned to be integrated to the loop (systems for the determination of moisture and other impurities in helium, etc.). The start of the HTHL operation is expected during 2011 and the integration of the active channel into the LVR-15 core during 2012.

  2. Design of a gap-adjustable inkjet printing system for dense and high-temperature-melting materials

    Science.gov (United States)

    Lee, Taik-Min; Jo, Jeong-Dai; Kim, Hyun-Sub; Ham, Young-Bok; Yoon, So-Nam; Kim, Kwang-Young

    2005-01-01

    Inkjet printing technology has begun to get into the spotlight in many ways due to the superior price competitiveness to existent semi-conductor process. This paper will introduce a newly devised gap adjustable inkjet printing system for dense and high-temperature-melting materials such as metal paste. The design on the gap adjustable inkjet printing system is discussed in detail for precise control of the size and spacing of the injected metal droplets. Analytic optimization and effects of design parameters are examined and computational work using the axis-symmetric, incompressible, multiphase equations is carried out to predict characteristics of the metal paste jetting and to design optimal micro nozzle prototype. From this analysis, droplet trajectory visualization and velocity vector of ejected droplet have been investigated to characterize the relationship between inlet condition and nozzle profile. Finally, the designed gap adjustable inkjet printing system is fabricated and its peformances are tested according to the change of various gap distances and the droplet characteristics are measured in the view point of precise droplet controllability and productivity.

  3. Nanoporous gold synthesized by plasma-assisted inert gas condensation: room temperature sintering, nanoscale mechanical properties and stability against high energy electron irradiation

    Science.gov (United States)

    Weyrauch, S.; Wagner, C.; Suckfuell, C.; Lotnyk, A.; Knolle, W.; Gerlach, J. W.; Mayr, S. G.

    2018-02-01

    With a plasma assisted gas condensation system it is possible to achieve high-purity nanoporous Au (np-Au) structures with minimal contaminations and impurities. The structures consist of single Au-nanoparticles, which partially sintered together due to their high surface to volume ratio. Through electron microscopy investigations a porosity  >50% with ligament sizes between 20–30 nm was revealed. The elastic modulus of the np-Au was determined via peak force quantitative nanomechanical mapping and resulted in values of 7.5  ±  1.5 GPa. The presented structures partially sintered at room temperature, but proved to be stable to electron irradiation with energies of 7 MeV up to doses of 100 MGy. The electron irradiation stability opens the venue for electron assisted functionalization with biomolecules.

  4. A SnOx-brookite TiO2 bilayer electron collector for hysteresis-less high efficiency plastic perovskite solar cells fabricated at low process temperature.

    Science.gov (United States)

    Kogo, Atsushi; Ikegami, Masashi; Miyasaka, Tsutomu

    2016-06-21

    Thin plastic film-based CH3NH3PbI3-xClx perovskite solar cells were fabricated at low process temperature using a bilayer comprising an amorphous SnOx and mesoporous brookite TiO2 as electron collectors. Void-less high quality heterojunction structures achieve hysteresis-less photovoltaic performance with a power conversion efficiency as high as 13.4% and mechanical stability against cyclic bending.

  5. Density and temperature of energetic electrons in the Earth's magnetotail derived from high-latitude GPS observations during the declining phase of the solar cycle

    Directory of Open Access Journals (Sweden)

    M. H. Denton

    2011-10-01

    Full Text Available Single relativistic-Maxwellian fits are made to high-latitude GPS-satellite observations of energetic electrons for the period January 2006–November 2010; a constellation of 12 GPS space vehicles provides the observations. The derived fit parameters (for energies ~0.1–1.0 MeV, in combination with field-line mapping on the nightside of the magnetosphere, provide a survey of the energetic electron density and temperature distribution in the magnetotail between McIlwain L-values of L=6 and L=22. Analysis reveals the characteristics of the density-temperature distribution of energetic electrons and its variation as a function of solar wind speed and the Kp index. The density-temperature characteristics of the magnetotail energetic electrons are very similar to those found in the outer electron radiation belt as measured at geosynchronous orbit. The energetic electron density in the magnetotail is much greater during increased geomagnetic activity and during fast solar wind. The total electron density in the magnetotail is found to be strongly correlated with solar wind speed and is at least a factor of two greater for high-speed solar wind (VSW=500–1000 km s−1 compared to low-speed solar wind (VSW=100–400 km s−1. These results have important implications for understanding (a how the solar wind may modulate entry into the magnetosphere during fast and slow solar wind, and (b if the magnetotail is a source or a sink for the outer electron radiation belt.

  6. Density and temperature of energetic electrons in the Earth's magnetotail derived from high-latitude GPS observations during the declining phase of the solar cycle

    Directory of Open Access Journals (Sweden)

    M. H. Denton

    2011-10-01

    Full Text Available Single relativistic-Maxwellian fits are made to high-latitude GPS-satellite observations of energetic electrons for the period January 2006–November 2010; a constellation of 12 GPS space vehicles provides the observations. The derived fit parameters (for energies ~0.1–1.0 MeV, in combination with field-line mapping on the nightside of the magnetosphere, provide a survey of the energetic electron density and temperature distribution in the magnetotail between McIlwain L-values of L=6 and L=22. Analysis reveals the characteristics of the density-temperature distribution of energetic electrons and its variation as a function of solar wind speed and the Kp index. The density-temperature characteristics of the magnetotail energetic electrons are very similar to those found in the outer electron radiation belt as measured at geosynchronous orbit. The energetic electron density in the magnetotail is much greater during increased geomagnetic activity and during fast solar wind. The total electron density in the magnetotail is found to be strongly correlated with solar wind speed and is at least a factor of two greater for high-speed solar wind (VSW=500–1000 km s−1 compared to low-speed solar wind (VSW=100–400 km s−1. These results have important implications for understanding (a how the solar wind may modulate entry into the magnetosphere during fast and slow solar wind, and (b if the magnetotail is a source or a sink for the outer electron radiation belt.

  7. Material for electrodes of low temperature plasma generators

    Science.gov (United States)

    Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich

    2008-12-09

    Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

  8. Development of high temperature liquid metal test facilities for qualification of materials and investigations of thermoelectrical modules

    Science.gov (United States)

    Onea, A.; Hering, W.; Reiser, J.; Weisenburger, A.; Diez de los Rios Ramos, N.; Lux, M.; Ziegler, R.; Baumgärtner, S.; Stieglitz, R.

    2017-07-01

    Three classes of experimental liquid metal facilities have been completed during the LIMTECH project aiming the qualification of materials, investigation of thermoelectrical modules, investigation of sodium transitional regimes and fundamental thermo-dynamical flows in concentrating solar power (CSP) relevant geometries. ATEFA facility is dedicated to basic science investigation focussed on the alkali metal thermal-to-electric converter (AMTEC) technology. Three SOLTEC facilities are aimed to be used in different laboratories for long term material investigation sodium environment up to a 1000 K temperature and for long term tests of AMTEC modules. The medium scale integral facility KASOLA is planned as the backbone for CSP development and demonstration.

  9. Ab initio and Monte Carlo investigations of structural, electronic and magnetic properties of new ferromagnetic Heusler alloys with high Curie temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Dannenberg, Antje

    2011-08-30

    The mechanism which causes many of the unusual thermomechanical properties of martensitic alloys, as for example, superelasticity and the shape-memory effect, is the martensitic transformation. The prototype ferromagnetic shape memory alloy (FSMA) is Ni{sub 2}MnGa. But a technological breakthrough is missing due to its poor ductility and low operation temperatures. The goal of this thesis is the proposal of new FSMA appropriate for future technological applications. I focus on X{sub 2}YZ Heusler alloys which are mainly based on Mn, Fe, Co, and Ni for the X and Y sites and Z=Ga or Zn. The big challenge of this work is to find material classes which combine the unique magnetomechanical properties of FSMA which are large recoverable magnetostrictive strains, high magnetocrystalline anisotropy energy, and highly mobile twin boundaries with transformation temperatures clearly above room temperature and a reduced brittleness. Such a study, providing material classes which from a theoretical point of view are promising candidates for future FSMA, will help the experimental physicists to select interesting subgroups in the vast number of possible chemical compositions of X{sub 2}YZ Heusler alloys. I have systematically varied the composition in the new Heusler alloys in order to find trends indicating generic tendencies of the material properties, for instance, as a function of the valence electron concentration e/a. A main feature of this thesis is the attempt to find the origin of the competing structural ordering tendencies between conventional X{sub 2}YZ and inverse (XY)XZ Heusler structures which are observed for all systems investigated. In the first part of this work the accuracy and predictive power of ab initio and Monte Carlo simulations is demonstrated by reproducing the experimental phase diagram of Ni-Mn-(Ga,In,Sn,Sb). The linear increasing and decreasing slopes of T{sub M} and T{sub C} can be reproduced by total and free energy calculations and the analysis

  10. A high-throughput investigation of Fe-Cr-Al as a novel high-temperature coating for nuclear cladding materials.

    Science.gov (United States)

    Bunn, Jonathan Kenneth; Fang, Randy L; Albing, Mark R; Mehta, Apurva; Kramer, Matthew J; Besser, Matthew F; Hattrick-Simpers, Jason R

    2015-07-10

    High-temperature alloy coatings that can resist oxidation are urgently needed as nuclear cladding materials to mitigate the danger of hydrogen explosions during meltdown. Here we apply a combination of computationally guided materials synthesis, high-throughput structural characterization and data analysis tools to investigate the feasibility of coatings from the Fe–Cr–Al alloy system. Composition-spread samples were synthesized to cover the region of the phase diagram previous bulk studies have identified as forming protective oxides. The metallurgical and oxide phase evolution were studied via in situ synchrotron glancing incidence x-ray diffraction at temperatures up to 690 K. A composition region with an Al concentration greater than 3.08 at%, and between 20.0 at% and 32.9 at% Cr showed the least overall oxide growth. Subsequently, a series of samples were deposited on stubs and their oxidation behavior at 1373 K was observed. The continued presence of a passivating oxide was confirmed in this region over a period of 6 h.

  11. High temperature measuring device

    Science.gov (United States)

    Tokarz, Richard D.

    1983-01-01

    A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  12. High Performance Bulk Thermoelectric Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhifeng [Boston College, Chestnut Hill, MA (United States)

    2013-03-31

    Over 13 plus years, we have carried out research on electron pairing symmetry of superconductors, growth and their field emission property studies on carbon nanotubes and semiconducting nanowires, high performance thermoelectric materials and other interesting materials. As a result of the research, we have published 104 papers, have educated six undergraduate students, twenty graduate students, nine postdocs, nine visitors, and one technician.

  13. Influence of Crucible Materials on High-temperature Properties of Vacuum-melted Nickel-chromium-cobalt Alloy

    Science.gov (United States)

    Decker, R F; Rowe, John P; Freeman, J W

    1957-01-01

    A study of the effect of induction-vacuum-melting procedure on the high-temperature properties of a titanium-and-aluminum-hardened nickel-base alloy revealed that a major variable was the type of ceramic used as a crucible. Reactions between the melt and magnesia or zirconia crucibles apparently increased high-temperature properties by introducing small amounts of boron or zirconium into the melts. Heats melted in alumina crucibles had relatively low rupture life and ductility at 1,600 F and cracked during hot-working as a result of deriving no boron or zirconium from the crucible.

  14. [Determination of high temperature compressive strength and refractory degree of die material compatible with slip casting core of sintered titanium powder].

    Science.gov (United States)

    Kuang, X; Liao, Y; Chao, Y; Meng, Y

    1999-05-01

    The refractory die is the precondition for developing slip casting core of sintered powder. This study is to determine the high temperature properties of the refractory die material compatible with slip casting core. To prepare three cylindrical specimens (phi 10 x 15 mm) and determine their compressive strength at 1000 degrees C: to make four specimens in flat-topped cone for determining the practical refractory degree by decreasing the pressing temperatures in a sequence of 1420, 1400, 1350 and 1100 degrees C. The compressive strength of this material was 17.8 MPa at 1000 degrees C. Its practical refractory degree was higher than 1100 degrees C. The high temperature properties of the refractory die material that we developed meet the demand of slip casting core of sintered powder.

  15. Measurement of Creep Properties of Ultra-High-Temperature Materials by a Novel Non-Contact Technique

    Science.gov (United States)

    Hyers, Robert W.; Lee, Jonghyun; Rogers, Jan R.; Liaw, Peter K.

    2007-01-01

    A non-contact technique for measuring the creep properties of materials has been developed and validated as part of a collaboration among the University of Massachusetts, NASA Marshall Space Flight Center Electrostatic Levitation Facility (ESL), and the University of Tennessee. This novel method has several advantages over conventional creep testing. The sample is deformed by the centripetal acceleration from the rapid rotation, and the deformed shapes are analyzed to determine the strain. Since there is no contact with grips, there is no theoretical maximum temperature and no concern about chemical compatibility. Materials may be tested at the service temperature even for extreme environments such as rocket nozzles, or above the service temperature for accelerated testing of materials for applications such as jet engines or turbopumps for liquid-fueled engines. The creep measurements have been demonstrated to 2400 C with niobium, while the test facility, the NASA MSFC ESL, has processed materials up to 3400 C. Furthermore, the ESL creep method employs a distribution of stress to determine the stress exponent from a single test, versus the many tests required by conventional methods. Determination of the stress exponent from the ESL creep tests requires very precise measurement of the surface shape of the deformed sample for comparison to deformations predicted by finite element models for different stress exponents. An error analysis shows that the stress exponent can be determined to about 1% accuracy with the current methods and apparatus. The creep properties of single-crystal niobium at 1985 C showed excellent agreement with conventional tests performed according to ASTM Standard E-139. Tests on other metals, ceramics, and composites relevant to rocket propulsion and turbine engines are underway.

  16. Aluminum, copper, tin and lead as shielding materials in the treatment of cancer with high-energy electrons

    Science.gov (United States)

    Prasad, S. Guru; Parthasaradhi, K.; Bloomer, W. D.; Al-Najjar, W. H.; McMahon, J.; Thomson, O.

    1998-10-01

    During irradiation of lesions in cancer treatment with electrons, irregular field sizes are shaped by blocking off the areas to be protected usually with lead or Lepowitz metal of adequate thickness. Sometimes these blocks are placed directly on the skin. In such cases, the block should not only be of minimum weight (thickness), but also the residual dose received by the protected organs should be as small as possible. However, due to the production of bremsstrahlung, it is difficult to achieve a higher degree of attenuation unless a sufficient thickness of shielding material is used. Hence, a minimum or optimum thickness is needed to be measured. Transmission measurements are performed to determine suitable minimum thicknesses and to measure the transmission at this minimum thickness, for aluminum, copper, tin and lead for electron broad-beam field sizes 6×6, 10×10 and 20×20 cm 2 of energies 6, 12 and 20 MeV produced by a medical linear accelerator. The ratio of the measured ionization with and without the shielding material in percent is expressed as a measure of transmission. The minimum thickness is `knee' position of the transmission curves, where the dose received by the organs (residual dose) is mostly dominated by the bremsstrahlung component and any addition of shielding material is not of much advantage in achieving further appreciable shielding effect. It is noticed that at this minimum thickness the percentage dose received by the vital organs behind the shield varies from 1 to 14% of the original unshielded dose as the atomic number of the shielding material increases from 13 (aluminum) to 82 (lead) and as the electron energy of the beam increases from 6 to 20 MeV. In other words, the effectiveness of shielding decreases from 99 to 86% as the atomic number increases from 13 to 82. Depending on the treatment volume, its position and the clearance between the electron cone and the skin, the dose received by the vital organs surrounding the tumor can

  17. High-power electronics

    CERN Document Server

    Kapitsa, Petr Leonidovich

    1966-01-01

    High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

  18. Model for the high-temperature oxygen-ordering thermodynamics in YBa2Cu3O6+x - inclusion of electron spin and charge degrees of freedom

    DEFF Research Database (Denmark)

    Schleger, P.; Hardy, W.N.; Casalta, H.

    1994-01-01

    A lattice-gas model for the high temperature oxygen-ordering thermodynamics in YBa2Cu3O6+x is presented, which assumes constant effective pair interactions between oxygen atoms and includes in a simple fashion the effect of the electron spin and charge degrees of freedom. This is done using...... a commonly utilized picture relating the creation of mobile electron holes and unpaired spins to the insertion of oxygen into the basal plane. The model is solved using the nearest-neighbor square approximation of the cluster-variation method. In addition, preliminary Monte Carlo results using next...

  19. Achieving Stable Radiation Pressure Acceleration of Heavy Ions via Successive Electron Replenishment from Ionization of a High-Z Material Coating

    Science.gov (United States)

    Shen, X. F.; Qiao, B.; Zhang, H.; Kar, S.; Zhou, C. T.; Chang, H. X.; Borghesi, M.; He, X. T.

    2017-05-01

    A method to achieve stable radiation pressure acceleration (RPA) of heavy ions from laser-irradiated ultrathin foils is proposed, where a high-Z material coating in front is used. The coated high-Z material, acting as a moving electron repository, continuously replenishes the accelerating heavy ion foil with comoving electrons in the light-sail acceleration stage due to its successive ionization under laser fields with Gaussian temporal profile. As a result, the detrimental effects such as foil deformation and electron loss induced by the Rayleigh-Taylor-like and other instabilities in RPA are significantly offset and suppressed so that stable acceleration of heavy ions are maintained. Particle-in-cell simulations show that a monoenergetic Al13 + beam with peak energy 3.8 GeV and particle number 1 010 (charge >20 nC ) can be obtained at intensity 1 022 W /cm2 .

  20. Apparatus for the investigation of high-temperature, high-pressure gas-phase heterogeneous catalytic and photo-catalytic materials

    Science.gov (United States)

    Alvino, Jason F.; Bennett, Trystan; Kler, Rantej; Hudson, Rohan J.; Aupoil, Julien; Nann, Thomas; Golovko, Vladimir B.; Andersson, Gunther G.; Metha, Gregory F.

    2017-05-01

    A high-temperature, high-pressure, pulsed-gas sampling and detection system has been developed for testing new catalytic and photocatalytic materials for the production of solar fuels. The reactor is fitted with a sapphire window to allow the irradiation of photocatalytic samples from a lamp or solar simulator light source. The reactor has a volume of only 3.80 ml allowing for the investigation of very small quantities of a catalytic material, down to 1 mg. The stainless steel construction allows the cell to be heated to 350 °C and can withstand pressures up to 27 bar, limited only by the sapphire window. High-pressure sampling is made possible by a computer controlled pulsed valve that delivers precise gas flow, enabling catalytic reactions to be monitored across a wide range of pressures. A residual gas analyser mass spectrometer forms a part of the detection system, which is able to provide a rapid, real-time analysis of the gas composition within the photocatalytic reaction chamber. This apparatus is ideal for investigating a number of industrially relevant reactions including photocatalytic water splitting and CO2 reduction. Initial catalytic results using Pt-doped and Ru nanoparticle-doped TiO2 as benchmark experiments are presented.

  1. Apparatus for the investigation of high-temperature, high-pressure gas-phase heterogeneous catalytic and photo-catalytic materials.

    Science.gov (United States)

    Alvino, Jason F; Bennett, Trystan; Kler, Rantej; Hudson, Rohan J; Aupoil, Julien; Nann, Thomas; Golovko, Vladimir B; Andersson, Gunther G; Metha, Gregory F

    2017-05-01

    A high-temperature, high-pressure, pulsed-gas sampling and detection system has been developed for testing new catalytic and photocatalytic materials for the production of solar fuels. The reactor is fitted with a sapphire window to allow the irradiation of photocatalytic samples from a lamp or solar simulator light source. The reactor has a volume of only 3.80 ml allowing for the investigation of very small quantities of a catalytic material, down to 1 mg. The stainless steel construction allows the cell to be heated to 350 °C and can withstand pressures up to 27 bar, limited only by the sapphire window. High-pressure sampling is made possible by a computer controlled pulsed valve that delivers precise gas flow, enabling catalytic reactions to be monitored across a wide range of pressures. A residual gas analyser mass spectrometer forms a part of the detection system, which is able to provide a rapid, real-time analysis of the gas composition within the photocatalytic reaction chamber. This apparatus is ideal for investigating a number of industrially relevant reactions including photocatalytic water splitting and CO2 reduction. Initial catalytic results using Pt-doped and Ru nanoparticle-doped TiO2 as benchmark experiments are presented.

  2. Material Specific Design for Room Temperature Superconductivity

    Science.gov (United States)

    Isikaku-Ironkwe, O.-Paul; Ofe, Uko; Oriaku, Chijioke; Asiegbu, Dan; Oguzi, Emeka

    2012-02-01

    The transition temperature, Tc, of superconductors has been increased sevenfold from 23K in Nb3Ge to 164K in Hg-1223. A further two-fold increase would get us to above room temperature superconductivity. Studying high temperature superconductors (HTSCs), we have developed a formula that expresses Tc in terms of electronegativity, valence electrons, Ne, atomic number, Z, formula mass and a coupling constant, Ko. We observe an increasing linear relationship between Tc and Ko. Ko also correlates with formula mass and atomic number and the number of atoms in the compound. By our formula, Hg-1223 has Ko = 70. We propose, using our design algorithm, that room temperature superconductivity may be realized in a system with ko = 160; electronegativity = 2.5, Ne/Sqrt Z = 0.8. We proceed to show combinations of oxides and elements that will yield the required parameters for synthesizing reproducible room temperature superconductivity.

  3. High temperature superconductor current leads

    Science.gov (United States)

    Hull, John R.; Poeppel, Roger B.

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  4. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Wate Bakker

    2004-03-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  5. Report on the possible benefits of using high-temperature superconductor materials in particle-accelerator design. Final report, June-September 1987

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, L.; Collins, R.; Balko, B.

    1988-12-01

    This report discusses different design concepts for particle-beam accelerators. It demonstrates that with the use of high-temperature superconducting materials, a more-compact, lighter, and more-robust accelerator design can be realized for the space-based neutral particle beam (NPB) accelerator.

  6. Compact district heating stations for low return flow temperatures. High-quality materials and components; Fernwaermekompaktstationen fuer niedrige Ruecklauftemperaturen. Hochwertige Werkstoffe und Komponenten

    Energy Technology Data Exchange (ETDEWEB)

    Ewers, Frank; Eickmeyer, Klaus [Ewers Heizungstechnik GmbH, Schloss Holte-Stukenbrock (Germany)

    2011-04-15

    Efficient district heating transmission stations and reliable operation ensured by high-quality materials and components are important both for grid operators and consumers. Low return flow temperatures are desirable for better power plant operation. Transmission stations should also be compact, easy to instal and operate, and should have an aesthetically pleasing design.

  7. Comprehensive inter-laboratory calibration of reference materials for delta O-18 versus VSMOW using various on-line high-temperature conversion techniques

    NARCIS (Netherlands)

    Brand, Willi A.; Coplen, Tyler B.; Aerts-Bijma, Anita T.; Böhlke, J.K.; Gehre, Matthias; Geilmann, Heike; Gröning, Manfred; Jansen, Henk G.; Meijer, Harro A. J.; Mroczkowski, Stanley J.; Qi, Haiping; Soergel, Karin; Stuart-Williams, Hilary; Weise, Stephan M.; Werner, Roland A.

    2009-01-01

    Internationally distributed organic and inorganic oxygen isotopic reference materials have been calibrated by six laboratories carrying out more than 5300 measurements using a variety of high-temperature conversion techniques (HTC)a in an evaluation sponsored by the International Union of Pure and

  8. Materials Properties Database for Selection of High-Temperature Alloys and Concepts of Alloy Design for SOFC Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z Gary; Paxton, Dean M.; Weil, K. Scott; Stevenson, Jeffry W.; Singh, Prabhakar

    2002-11-24

    To serve as an interconnect / gas separator in an SOFC stack, an alloy should demonstrate the ability to provide (i) bulk and surface stability against oxidation and corrosion during prolonged exposure to the fuel cell environment, (ii) thermal expansion compatibility with the other stack components, (iii) chemical compatibility with adjacent stack components, (iv) high electrical conductivity of the surface reaction products, (v) mechanical reliability and durability at cell exposure conditions, (vii) good manufacturability, processability and fabricability, and (viii) cost effectiveness. As the first step of this approach, a composition and property database was compiled for high temperature alloys in order to assist in determining which alloys offer the most promise for SOFC interconnect applications in terms of oxidation and corrosion resistance. The high temperature alloys of interest included Ni-, Fe-, Co-base superal

  9. High Temperature Mechanical Properties, Fractography and Synchrotron Studies of ATF clad materials from the UCSB-NSUF Irradiations.

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, Tarik A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Romero, Tobias J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sprouster, David [Brookhaven National Lab. (BNL), Upton, NY (United States); Ecker, Lynne [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-02-23

    A variety of tensile samples of Ferritic and Oxide Dispersion Strengthened (ODS or nanostructured ferritic) steels were placed the ATR reactor over 2 years achieving doses of roughly 4-6 dpa at temperatures of roughly 290°C. Samples were shipped to Wing 9 in the CMR facility at Los Alamos National Laboratory and imaged then tested in tension. This report summarizes the room temperature tensile tests, the elevated temperature tensile tests (300°C) and fractography and reduction of area calculations on those samples. Additionally small samples were cut from the undeformed grip section of these tensile samples and sent to the NSLS synchrotron for high energy X-ray analysis, initial results will be described here.

  10. Protection Of TEG Module at High Temperature Transient Boundary Condition Using Phase Change Materials, an Experimental Investigation

    DEFF Research Database (Denmark)

    Ahmadi Atouei,, Saeed; Rezaniakolaei, Alireza; Akbar Ranjbar, Ali

    2017-01-01

    phase change materials (PCM) in an aluminium box are placed between heat source and the thermoelectric module. The results show when the input heat flux is high, a fraction of the thermal energy is saved in the PCM during the melting process, and when the heat source is off, the saved energy in the PCM...

  11. Corrosion of metallic materials by uranium hexafluoride at high temperatures (1963); Corrosion de materiaux metalliques par l'hexafluorure d'uranium a haute temperature (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Langlois, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The corrosion of the following metals or alloys by UF{sub 6}: nickel, monel, Inconel, gold, platinum, stainless steel, is studied in the temperature range from 300 to 1000 deg. C. The test method, designed to avoid heating the apparatus containing the corrosive fluid to a high temperature, consists in using threadlike samples heated by the Joule effect, the rest of the apparatus being maintained close to room temperature. This technique makes it possible also to determine continuously the penetration of the corrosion by measuring the electrical resistance of the sample with a double Thomson bridge. A series of rapid comparison tests shows that stainless steel, precious metals and Inconel are attacked far too rapidly to be used above 500 deg. C; only monel and especially nickel appear capable of resisting at high temperatures. The detailed examination of the behaviour of nickel shows that the metallic fluoride is volatilized and that this influences the corrosion rate. It shows also the existence of a temperature zone situated between 550 and 700 deg. C in which occurs A strong intergranular corrosion the cause of which appears to be the presence of impurities in the metal. (author) [French] La corrosion par l'UF{sub 6} des metaux ou alliages suivants: lickel, monel, inconel, or, platine, acier inoxydable, est etudiee dans le un domaine de temperature compris entre 300 et 1000 deg. C. La methode d'essai, destinee a eviter le chauffage de l'enceinte contenant le fluide corrosif a temperature elevee, consiste a utiliser des eprouvettes filiformes, echauffees par effet Joule, le reste de l'appareillage etant maintenu a une temperature proche de l'ambiance. Cette technique permet en outre de determiner en continu la penetration de la corrosion, par mesure de la resistance electrique de l'eprouvette, au moyen d'un pont double de Thomson. Une serie d'essais comparatifs, assez sommaires, montre que l'acier inoxydable, les metaux

  12. All-inkjet-printed flexible electronics fabrication on a polymer substrate by low-temperature high-resolution selective laser sintering of metal nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Seung H [Department of Mechanical Engineering, University of California, 6177 Etcheverry Hall, Berkeley, CA 94720-1740 (United States); Pan Heng [Department of Mechanical Engineering, University of California, 6177 Etcheverry Hall, Berkeley, CA 94720-1740 (United States); Grigoropoulos, Costas P [Department of Mechanical Engineering, University of California, 6177 Etcheverry Hall, Berkeley, CA 94720-1740 (United States); Luscombe, Christine K [Department of Chemistry, University of California, Berkeley, CA 94720-1460 (United States); Frechet, Jean M J [Department of Chemistry, University of California, Berkeley, CA 94720-1460 (United States); Poulikakos, Dimos [Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical and Process Engineering, ETH Zurich, CH-8092 Zurich (Switzerland)

    2007-08-29

    All-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that laser sintering of inkjet-printed metal nanoparticles enables low-temperature metal deposition as well as high-resolution patterning to overcome the resolution limitation of the current inkjet direct writing processes. To demonstrate this process combined with the implementation of air-stable carboxylate-functionalized polythiophenes, high-resolution organic transistors were fabricated in ambient pressure and room temperature without utilizing any photolithographic steps or requiring a vacuum deposition process. Local thermal control of the laser sintering process could minimize the heat-affected zone and the thermal damage to the substrate and further enhance the resolution of the process. This local nanoparticle deposition and energy coupling enable an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, flexible electronics on polymer substrates.

  13. Fast transient infrared studies in material science: development of a novel low dead-volume, high temperature DRIFTS cell.

    Science.gov (United States)

    Dal Santo, V; Dossi, C; Fusi, A; Psaro, R; Mondelli, C; Recchia, S

    2005-04-30

    A prototype DRIFTS flow reaction chamber was designed and developed in order to find analytical application in the study of heterogeneous catalysts operating at high temperatures under fast transient gas feed conditions. Minimisation of dead-volumes allows gas replacement in 8-10s at 10mLmin(-1) total flow. To overcome problems related to the reactivity of the cell walls under alternating oxidizing/reducing gases, the cell was built with Inconel 600trade mark, which was tested to be very inert even at high temperatures. The sample holder, which was developed to closely resemble a micro plug-flow reactor, poses some problems in terms of heat transfer to the outer body of the cell (limiting then the maximum reachable temperature) and of the correct measurement of the actual sample temperature. These problems were solved with a careful re-design of the upper part of the cell. The second prototype thus derived is able to reach temperatures up to 803K and allows gas replacement in less than 4s at 10mLmin(-1). The cell is inserted in a MCT-FT-IR, which allows to collect high quality spectra with a 1s time-resolution. The downstream flow can be analysed by a quadrupole mass spectrometer equipped with an enclosed source and by a commercial GC. The performances of this prototype cell are presented showing some tests carried out with ceria-zirconia (Ce(x)Zr(1-x)O(2)) catalysts for CO abatement under real operando conditions.

  14. Engineering of Highly Susceptible Paramagnetic Nanostructures of Gd2S3:Eu3+: Potentially an Efficient Material for Room Temperature Gas Sensing Applications

    Directory of Open Access Journals (Sweden)

    Muhammed M. Radhi

    2010-11-01

    Full Text Available This research papers throws light into the compositional, morphological and structural properties of novel nanoparticles of Gd2S3:Eu3+ synthesized by a simple co-precipitation technique. Furthermore, we also prognosticate that this material could be useful for gas sensing applications at room temperature. Nanostructures formulation by this method resulted in the formation of orthorhombic crystal structure with primitive lattice having space group Pnma. The material characterizations are performed using X-ray diffraction (XRD, energy dispersive X-ray analysis (EDX, thermo-gravimetric analysis/differential thermal analysis (TGA/DTA and transmission electron microscope (TEM. The calculated crystallite sizes are ~ 2-5 nm and are in well accordance with the HRTEM results. EDX result confirms the presence and homogeneous distribution of Gd and Eu throughout the nanoparticle. The prepared nanoparticles exhibit strong paramagnetic nature with paramagnetic term, susceptibility c = 8.2 ´ 10-5 emg/g Gauss. TGA/DTA analysis shows 27 % weight loss with rise in temperature. The gas sensing capability of the prepared Gd2S3:Eu3+ magnetic nanoparticles are investigated using the amperometric method. These nanoparticles show good I-V characteristics with ideal semiconducting nature at room temperature with and without ammonia dose. The observed room temperature sensitivity with increasing dose of ammonia indicates applicability of Gd2S3 nanoparticles as room temperature ammonia sensors.

  15. Instrumentated indentation test at high temperature for the characterization of irradiated materials; Instrumentierte Eindringpruefung bei Hochtemperatur fuer die Charakterisierung bestrahlter Materialien

    Energy Technology Data Exchange (ETDEWEB)

    Albinski, Bartlomiej

    2014-07-01

    Predicting the behavior of structural materials assigned to the use in future fusion reactors is an essential part in their development and design. Mechanical testing characterizes the new designed materials. In these tests, the expected operating conditions, i. e. high temperatures and radiation damage, have to be simulated. For this purpose, instrumented indentation is a particularly capable testing method. The relationship of force and indentation depth recorded during the indentation of a hard tip into a specimen allows to predict the mechanical parameters of the tested material. Stress and strain appearing in the material can be excerpted when using a spherical indenter tip. Consequently, besides material's hardness and Young's modulus its properties in the plastic regime can be described. Reproducing the operating conditions of a fusion reactor for the indentation test bases on two aspects. First, irradiated samples need to be tested by remote-handling methods. Second, the samples have to be heated for the experiment. Both of these requirements lead to a new testing device that allows instrumented indentation on irradiation damaged materials in a remote-handled way at temperatures up to 650 C. Installation, set-up and initial operation of this newly designed apparatus are described. This includes design and integration of the components contributing to the indentation test, the systems for measurement and feedback control of the testing parameters sample temperature, indentation force, indentation depth and time as well as supporting gear and peripherals. Existing boundary conditions have to be incorporated in this process. Experimental verification and calibration of each subsystem is done. The proper interaction between the subsystems proves the functional capability and reliability of the new high-temperature indentation device. Material tests were accomplished on a reduced-activation ferritic-martensitic steel, tungsten and tantalum using the

  16. High temperature battery. Hochtemperaturbatterie

    Energy Technology Data Exchange (ETDEWEB)

    Bulling, M.

    1992-06-04

    To prevent heat losses of a high temperature battery, it is proposed to make the incoming current leads in the area of their penetration through the double-walled insulating housing as thermal throttle, particularly spiral ones.

  17. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also...... input to the cell then hydrogen is produced giving syngas. This syngas can then be further reacted to form hydrocarbon fuels and chemicals. Operating at high temperature gives much higher efficiencies than can be achieved with low temperature electrolysis. Current state of the art SOECs utilise a dense...

  18. HIGH TEMPERATURE VACUUM MIXER

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2015-01-01

    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  19. High Temperature QCD

    CERN Document Server

    Lombardo, M P

    2012-01-01

    I review recent results on QCD at high temperature on a lattice. Steady progress with staggered fermions and Wilson type fermions allow a quantitative description of hot QCD whose accuracy in many cases parallels that of zero temperature studies. Simulations with chiral quarks are coming of age, and togheter with theoretical developments trigger interesting developments in the analysis of the critical region. Issues related with the universality class of the chiral transition and the fate of the axial symmetry are discussed in the light of new numerical and analytical results. Transport coefficients and analysis of bottomonium spectra compare well with results of heavy ion collisions at RHIC and LHC. Model field theories, lattice simulations and high temperature systematic expansions help building a coherent picture of the high temperature phase of QCD. The (strongly coupled) Quark Gluon Plasma is heavily investigated, and asserts its role as an inspiring theoretical laboratory.

  20. High Temperature Hybrid Elastomers

    Science.gov (United States)

    Drake, Kerry Anthony

    Conventional high temperature elastomers are produced by chain polymerization of olefinic or fluorinated olefinic monomers. Ultimate thermal stabilities are limited by backbone bond strengths, lower thermal stability of cross-link sites relative to backbone bonds, and depolymerization or "unzipping" at high temperatures. In order to develop elastomers with enhanced thermal stability, hybrid thermally cross-linkable polymers that consisted only of organic-inorganic and aromatic bonds were synthesized and evaluated. The addition of phenylethynyl or phenylacetylinic functional groups to these polymers resulted in conversion of the polymers into high temperature elastomers when cross-linked by thermal curing. Polyphenyoxydiphenylsilanes were synthesized via several different condensation reactions. Results of these synthetic reactions, which utilized both hydroquinone and biphenol as monomers, were systematically evaluated to determine the optimal synthetic conditions for subsequent endcapping reactions. It was determined that dichlorodiphenylsilane condensations with biphenol in toluene or THF were best suited for this work. Use of excess dichlorodiphenylsilane yielded polymers of appropriate molecular weights with terminal reactive chlorosilane groups that could be utilized for coupling with phenylethynyl reagents in a subsequent reaction. Two new synthetic routes were developed to endcap biphenoxysilanes with ethynyl containing substituents, to yield polymers with cross-linkable end groups. Endcapping by lithiumphenylacetylide and 4[(4-fluorophenylethynyl))phenol yielded two new polymers that could be thermally cross-linked on heating above 300 °C. Successful endcapping was verified chemically by 13C NMR, FTIR and Raman analysis. Exothermic peaks consistent with ethynyl curing reactions were observed in endcapped polymers by DSC. A new diacetylinic polymer was prepared through reaction of 4,4'-buta-1,3-diyne-1,4-diyldiphenol and dichlorodiphenylsilane. This

  1. Temperature distribution in a sample with second-phase microinclusions during irradiation by a low-energy high-current pulsed electron beam

    Science.gov (United States)

    Shepel', D. A.; Markov, A. B.

    2017-02-01

    Using the methods of numerical integration, a temperature field has been calculated that arose in the surface layer of titanium nickelide target with NiTi2 intermetallic inclusions during irradiation by a lowenergy high-current electron beam with a duration of the order of a microsecond. The calculated temperature field has been compared with that obtained previously for a target of stainless steel 316L containing MnS inclusions. It has been found that, as in the case of stainless steel, the regions of inclusions are overheated. However, the temperature increase for NiTi2 (12 K) is significantly lower than in the case of stainless steel 316L (283 K). The dynamics of melting of these systems are also considerably different.

  2. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  3. Standard Test Method for Testing Polymeric Seal Materials for Geothermal and/or High Temperature Service Under Sealing Stress

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1985-01-01

    1.1 This test method covers the initial evaluation of (screening) polymeric materials for seals under static sealing stress and at elevated temperatures. 1.2 This test method applies to geothermal service only if used in conjunction with Test Method E 1068. 1.3 The test fluid is distilled water. 1.4 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...... electrolysis using SOECs is competitive to H-2 production from fossil fuels at electricity prices below 0.02-0.03 is an element of per kWh. Though promising SOEC results on H-2 production have been reported a substantial R&D is still required to obtain inexpensive, high performing and long-term stable...

  5. Holmium hafnate: An emerging electronic device material

    Science.gov (United States)

    Pavunny, Shojan P.; Sharma, Yogesh; Kooriyattil, Sudheendran; Dugu, Sita; Katiyar, Rajesh K.; Scott, James F.; Katiyar, Ram S.

    2015-03-01

    We report structural, optical, charge transport, and temperature properties as well as the frequency dependence of the dielectric constant of Ho2Hf2O7 (HHO) which make this material desirable as an alternative high-k dielectric for future silicon technology devices. A high dielectric constant of ˜20 and very low dielectric loss of ˜0.1% are temperature and voltage independent at 100 kHz near ambient conditions. The Pt/HHO/Pt capacitor exhibits exceptionally low Schottky emission-based leakage currents. In combination with the large observed bandgap Eg of 5.6 eV, determined by diffuse reflectance spectroscopy, our results reveal fundamental physics and materials science of the HHO metal oxide and its potential application as a high-k dielectric for the next generation of complementary metal-oxide-semiconductor devices.

  6. Holmium hafnate: An emerging electronic device material

    Energy Technology Data Exchange (ETDEWEB)

    Pavunny, Shojan P., E-mail: shojanpp@gmail.com, E-mail: rkatiyar@hpcf.upr.edu; Sharma, Yogesh; Kooriyattil, Sudheendran; Dugu, Sita; Katiyar, Rajesh K.; Katiyar, Ram S., E-mail: shojanpp@gmail.com, E-mail: rkatiyar@hpcf.upr.edu [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, P.O. Box 70377, San Juan, Puerto Rico 00936-8377 (United States); Scott, James F. [Department of Physics and Institute for Functional Nanomaterials, University of Puerto Rico, P.O. Box 70377, San Juan, Puerto Rico 00936-8377 (United States); Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge CB3 OHE (United Kingdom)

    2015-03-16

    We report structural, optical, charge transport, and temperature properties as well as the frequency dependence of the dielectric constant of Ho{sub 2}Hf{sub 2}O{sub 7} (HHO) which make this material desirable as an alternative high-k dielectric for future silicon technology devices. A high dielectric constant of ∼20 and very low dielectric loss of ∼0.1% are temperature and voltage independent at 100 kHz near ambient conditions. The Pt/HHO/Pt capacitor exhibits exceptionally low Schottky emission-based leakage currents. In combination with the large observed bandgap E{sub g} of 5.6 eV, determined by diffuse reflectance spectroscopy, our results reveal fundamental physics and materials science of the HHO metal oxide and its potential application as a high-k dielectric for the next generation of complementary metal-oxide-semiconductor devices.

  7. Study of high temperature ceramic turbocharger. ; Basic research on turbine housing materials. Koon ceramic turbocharger no kenkyu. ; Turbine shashitsu zairyo no kiso shiken

    Energy Technology Data Exchange (ETDEWEB)

    Miyashita, K.; Miyagi, Y.; Sugihara, H.; Kitagawa, M. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1991-04-01

    In order to engineer the development of high temperature ceramic turbocharger for the gasoline engine use, characteristics at high temperature were studied of ceramics-made turbine impeller and turbine housing material. Used ceramics is silica nitride, developed for the gas turbine use and sintered under the atmospheric pressure. Prototypically prepared turbine rotors, designed upon studying the centrifugal stress, thermal stress, impeller shape and joint strength between the impellers and metallic shaft, were durable against 1050 centigrade in turbine inlet gas temperature (TIT), as a result of reliability evaluation test thereon. The turbine housing material comprises five categories such as stainless steel, Ni-resist cast iron and N155 (turbocharger housing material for the race use). As a comparative result of high temperature tensile strength, thermal cycle oxidation and thermal fatigue tests, the stainless steel was excellent in oxidation characteristics and at the equal level to the N155 in thermal fatigue strength at 1050 centigrade in TIT. 5 refs., 18 figs., 2 tabs.

  8. Colloquium 3: Thermal insulation materials in construction and in high-temperature plants. Lectures; Kolloquium 3: Waermedaemmstoffe im Bauwesen und in Hochtemperaturanlagen. Vortraege

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, E.; Gross, U.; Walter, G. [comps.

    1999-07-01

    Colloquium 3, ''Thermal insulation materials in construction and in high-temperature plants'' focused, for one thing, on the inter-relationships between the development of thermal insulation materials for construction and high-temperature applications and the development of processes and plants and, for another, on the standards of and amendments to the thermal protection ordinance. Calcium silicate and Silcapor as a thermal protection material and a high-temperature thermal insulant, respectively, are dealt with inter alia. The use of thermal insulants in industrial furnaces and different methods for measuring thermal conductivity are described. Further topics are the elements of the energy conservation ordinance being drafted, and thermal-insulation construction materials such as bricks and foam mortar. Ten papers are individually listed in the Energy database. (orig.) [German] Im Mittelpunkt des Kolloquium 3 ''Waermedaemmstoffe im Bauwesen und in Hochtemperaturanlagen'' stehen die wechselseitigen Zusammenhaenge zwischen der Entwicklung von Waermedaemmstoffen fuer das Bauwesen und die Hochtemperaturanwendung einerseits und der Prozess-und Anlagenentwicklung anderseits sowie die Normung und die Novellierung der Waermeschutzverordnung. Es wird u.a. auf den Waermedaemmstoff Calciumsilicat eingegangen ebensowie auf Silcapor als Hochtemperaturd ammstoff. Der Einsatz von Waermedaemmstoffen in Industrieoefen sowie die unterschiedlichen Messmethoden der Waermeleitfaehigkeit werden beschrieben. Weitere Themen sind die Grundlagen der kuenftigen Energiesparverordnung sowie waermedaemmende Baustoffe wie Ziegel und Porenbeton. Fuer die Datenbank Energy wurden zehn Arbeiten separat aufgenommen.

  9. Room- and low-temperature assessment of pseudomorphic AlGaAs/InGaAs/GaAS high-electron-mobility transistor structures by photoluminescence spectroscopy

    Science.gov (United States)

    Gilperez, J. M.; Sanchez-Rojas, J. L.; Munoz, E.; Calleja, E.; David, J. P. R.; Reddy, M.; Hill, G.; Sanchez-Dehesa, J.

    1994-11-01

    The use of room- and low-temperature photoluminescence (PL) spectroscopy for the assessment of n-type pseudomorphic AlGaAs/InGaAs/GaAs high-electron-mobility transistor stransitor structures is reported. We describe a method to determine the InAs mole fraction x, the channel layer thickness L, and the confined two-dimensional electron gas density (n(sub s)), based on the comparison between the PL transitions and the recombination energies derived from self-consistent calculations of the subband structure. A detailed analysis of the optical transitions and their dependence on the Fermi level position and temperature is performed. It is shown that, in real devices, the high sensitivity of the recombination energies and intensities on small changes of the parameters x, L, and n(sub s) allows us to detect deviations from their nominal structural parameters within the uncertainty of the molecular beam epitaxy growth technique. The present assessment procedure has been applied to a significant number of samples, and it has been backed by independent measurements of these parameters by more sophisticated techniques such as Shubnikov-de Haas and PL excitation in standard and gated samples, and by physical techniques like transmission electron microscopy and Auger spectroscopy.

  10. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  11. Composite Materials for Low-Temperature Applications

    Science.gov (United States)

    2008-01-01

    Composite materials with improved thermal conductivity and good mechanical strength properties should allow for the design and construction of more thermally efficient components (such as pipes and valves) for use in fluid-processing systems. These materials should have wide application in any number of systems, including ground support equipment (GSE), lunar systems, and flight hardware that need reduced heat transfer. Researchers from the Polymer Science and Technology Laboratory and the Cryogenics Laboratory at Kennedy Space Center were able to develop a new series of composite materials that can meet NASA's needs for lightweight materials/composites for use in fluid systems and also expand the plastic-additive markets. With respect to thermal conductivity and physical properties, these materials are excellent alternatives to prior composite materials and can be used in the aerospace, automotive, military, electronics, food-packaging, and textile markets. One specific application of the polymeric composition is for use in tanks, pipes, valves, structural supports, and components for hot or cold fluid-processing systems where heat flow through materials is a problem to be avoided. These materials can also substitute for metals in cryogenic and other low-temperature applications. These organic/inorganic polymeric composite materials were invented with significant reduction in heat transfer properties. Decreases of 20 to 50 percent in thermal conductivity versus that of the unmodified polymer matrix were measured. These novel composite materials also maintain mechanical properties of the unmodified polymer matrix. These composite materials consist of an inorganic additive combined with a thermoplastic polymer material. The intrinsic, low thermal conductivity of the additive is imparted into the thermoplastic, resulting in a significant reduction in heat transfer over that of the base polymer itself, yet maintaining most of the polymer's original properties. Normal

  12. A High-Temperature Order-Disorder Phase Transition Coupled With Conformational Change in the Hybrid Material [C6 H13 NH]2 ⋅ZnBr4.

    Science.gov (United States)

    Khan, Tariq; Asghar, Muhammad Adnan; Sun, Zhihua; Zeb, Aurang; Li, Lina; Sijie, Liu; Zhao, Sangen; Ji, Chengmin; Luo, Junhua

    2016-10-20

    A new high-temperature, hybrid, phase-transition material, 1-methylpiperidinium tetrabromozincate (1), that shows a reversible transition at 345 K was synthesized. Differential scanning calorimetry and specific heat capacity measurements confirmed this reversible transformation with a large heat hysteresis of 25 K, which describes a typical first-order phase transition in 1. The dielectric constant exhibited a steplike anomaly and showed high and low dielectric states in the high- and room-temperature phases, respectively, and therefore, this hybrid might be considered as a potential switchable dielectric material. The variable-temperature powder X-ray diffraction patterns displayed remarkable shifts between the experimental patterns at the two different phases. Single-crystal X-ray diffraction analyses at various temperatures revealed that the origin of this transformation could be attributed to disordering of the bromine atoms in the anion and the nitrogen atom of the cation. The cation also assumed a conformational change, which was likely induced by the disordered nitrogen atom. The conformational onset of the transformation of the cation from a planar conformer into a relaxed chair also occurred upon decreasing the temperature below transition point; thus, the combined order-disorder and conformational change induced the structural transformation and the change in symmetry. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Decal electronics for printed high performance cmos electronic systems

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-11-23

    High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications. While there exist bulk material reduction methods to flex them, such thinned CMOS electronics are fragile and vulnerable to handling for high throughput manufacturing. Here, we show a fusion of a CMOS technology compatible fabrication process for flexible CMOS electronics, with inkjet and conductive cellulose based interconnects, followed by additive manufacturing (i.e. 3D printing based packaging) and finally roll-to-roll printing of packaged decal electronics (thin film transistors based circuit components and sensors) focusing on printed high performance flexible electronic systems. This work provides the most pragmatic route for packaged flexible electronic systems for wide ranging applications.

  14. Characteristics of the Shanghai high-temperature superconducting electron-beam ion trap and studies of the space-charge effect under ultralow-energy operating conditions

    Science.gov (United States)

    Tu, B.; Lu, Q. F.; Cheng, T.; Li, M. C.; Yang, Y.; Yao, K.; Shen, Y.; Lu, D.; Xiao, J.; Hutton, R.; Zou, Y.

    2017-10-01

    A high-temperature superconducting electron-beam ion trap (EBIT) has been set up at the Shanghai EBIT Laboratory for spectroscopic studies of low-charge-state ions. In the study reported here, beam trajectory simulations are implemented in order to provide guidance for the operation of this EBIT under ultralow-energy conditions, which has been successfully achieved with a full-transmission electron-beam current of 1-8.7 mA at a nominal electron energy of 30-120 eV. The space-charge effect is studied through both simulations and experiments. A modified iterative formula is proposed to estimate the space-charge potential of the electrons and shows very good agreement with the simulation results. In addition, space-charge compensation by trapped ions is found in extreme ultraviolet spectroscopic measurements of carbon ions and is studied through simulation of ion behavior in the EBIT. Based on the simulation results, the ion-cloud radius, ion density, and electron-ion overlap are obtained.

  15. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  16. Estimating Seebeck Coefficient of a p-Type High Temperature Thermoelectric Material Using Bee Algorithm Multi-layer Perception

    Science.gov (United States)

    Uysal, Fatih; Kilinc, Enes; Kurt, Huseyin; Celik, Erdal; Dugenci, Muharrem; Sagiroglu, Selami

    2017-08-01

    Thermoelectric generators (TEGs) convert heat into electrical energy. These energy-conversion systems do not involve any moving parts and are made of thermoelectric (TE) elements connected electrically in a series and thermally in parallel; however, they are currently not suitable for use in regular operations due to their low efficiency levels. In order to produce high-efficiency TEGs, there is a need for highly heat-resistant thermoelectric materials (TEMs) with an improved figure of merit ( ZT). Production and test methods used for TEMs today are highly expensive. This study attempts to estimate the Seebeck coefficient of TEMs by using the values of existing materials in the literature. The estimation is made within an artificial neural network (ANN) based on the amount of doping and production methods. Results of the estimations show that the Seebeck coefficient can approximate the real values with an average accuracy of 94.4%. In addition, ANN has detected that any change in production methods is followed by a change in the Seebeck coefficient.

  17. Vaporization of materials in the operation of high temperature fuel cells (SOFCs); Verdampfung von Werkstoffen beim Betrieb von Hochtemperaturbrennstoffzellen (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, M.

    2006-07-01

    One of the main problems concerning the development of state of the art planar SOFCs are the occurrence of ageing effects in long term application. To a great deal these effects are caused by the release of volatile Cr-species from metallic interconnects which leads to an inhibition of the electrochemical processes at the cathode resulting in a rapid degradation of the cell performance. A goal in further development of SOFC-systems is the reduction of the operation temperature of the cell from currently 800 C to 700 C and below. For this purpose alternative electrolyte materials with higher oxygen ion conductivities have to be developed. Doped lanthanum gallates have been identified as promising materials. However for these materials a depletion of Ga by vaporization has been observed under anodic conditions which may lead to a destruction of their electrolyte properties. The aim of this work is the study of the vaporization processes leading to the mentioned degradation effects. For this purpose an experimental setup according to the transpiration method has been developed. Concerning the vaporization of chromium the Cr release rates of the main ferritic interconnect alloys, namely Crofer 22 APU, ZMG 232, E-Brite, IT-10, IT-11, IT-14 and Ducrolloy as well as a variety of Ni- and Co-base superalloys and stainless steels with different contents of Al, Si, Ti, Mn, W, Ni and Co were measured at 800 C in air and compared to each other. The alloys that form an upper layer of Cr-Mn-spinel on top of the grown chromia scale showed a reduction of the Cr release by 61-75 % compared to pure chromia scales whereas alloys with an outer Co3O4(s) scale had a by more than 90 % reduced Cr release. For the former alloys a significant vaporization of Mn under anodic conditions could be detected. Concerning the vaporization of doped lanthanum gallates the vaporization rates of the elements Ga, Mg, Sr and La were measured as function time, temperature, gas flow rate and stoichiometry

  18. Probing High Temperature Superconductors with Magnetometry in Ultrahigh Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-07-26

    The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and on potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.

  19. Dissolution chemistry and biocompatibility of single-crystalline silicon nanomembranes and associated materials for transient electronics.

    Science.gov (United States)

    Hwang, Suk-Won; Park, Gayoung; Edwards, Chris; Corbin, Elise A; Kang, Seung-Kyun; Cheng, Huanyu; Song, Jun-Kyul; Kim, Jae-Hwan; Yu, Sooyoun; Ng, Joanne; Lee, Jung Eun; Kim, Jiyoung; Yee, Cassian; Bhaduri, Basanta; Su, Yewang; Omennetto, Fiorenzo G; Huang, Yonggang; Bashir, Rashid; Goddard, Lynford; Popescu, Gabriel; Lee, Kyung-Mi; Rogers, John A

    2014-06-24

    Single-crystalline silicon nanomembranes (Si NMs) represent a critically important class of material for high-performance forms of electronics that are capable of complete, controlled dissolution when immersed in water and/or biofluids, sometimes referred to as a type of "transient" electronics. The results reported here include the kinetics of hydrolysis of Si NMs in biofluids and various aqueous solutions through a range of relevant pH values, ionic concentrations and temperatures, and dependence on dopant types and concentrations. In vitro and in vivo investigations of Si NMs and other transient electronic materials demonstrate biocompatibility and bioresorption, thereby suggesting potential for envisioned applications in active, biodegradable electronic implants.

  20. Passivation and corrosion of the high performance materials alloy 33, alloy 31 and nickel in LiBr solution at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Igual Munoz, A.; Garcia Anton, J.; Guinon, J.L.; Perez Herranz, V. [Departamento de Ingenieria Quimica y Nuclear. E.T.S. Industriales, Universidad Politecnica de Valencia, P.O. Box 22012, E-46071 Valencia (Spain)

    2004-07-01

    Aqueous solutions containing high concentrations of Lithium Bromide are employed as absorbent solutions for almost all types of heating and refrigerating absorption systems that use natural gas or steam as energy sources. LiBr solutions can cause serious corrosion problems in common metallic components. The objective of the present work was to study the corrosion resistance of new high alloyed materials in commercial LiBr heavy brine solution (which contains chromate as inhibitor), at different temperatures (25, 30, 40, 50, 60, 70 and 80 deg. C). The materials tested were stainless steels Alloy 33 (UNS R20033), a new corrosion resistant austenitic material alloyed with nominally (wt%) 33 Cr, 32 Fe, 31 Ni; Nicrofer 3127 hMo-alloy 31 (UNS N08031), an iron-nickel-chromium-molybdenum alloy with nitrogen; and pure Nickel. Corrosion resistance was estimated from the cyclic potentiodynamic polarization curves, comparing OCP values, calculating corrosion potentials and current rates from Tafel analysis; in order to characterize the passivating behaviour of the alloys the study was completed with the analysis of the pitting potentials, passivating current and re-passivating properties at the temperatures under study. Passivating properties are well observed in all the samples in commercial LiBr solution at all temperatures. In these cases, passivation properties decrease with temperature. (authors)

  1. High Power Electronics

    Science.gov (United States)

    Pendharker, Sameer

    High Power Electronics Future Trends: New process, circuit and packaging technologies over the last 5 years have led to significant innovation and technological developments in high power electronics. In this topic, the trends and performance improvements achieved in the industry will be discussed with focus on gallium-nitride (GaN) and silicon carbide (SiC). Both GaN and SiC technologies have been around for many years but have seen limited adoption and proliferation in high power systems. With the improved transistor performance, power conversion efficiencies and densities previously unrealizable are now available leading to new applications and new system. Trends in these technologies will also be reviewed and remaining challenges to overcome before true mass market adoption can be expected.

  2. TOPICAL REVIEW: Electron holography of magnetic materials

    Science.gov (United States)

    Shindo, Daisuke; Murakami, Yasukazu

    2008-09-01

    Electron holography, which visualizes magnetic and/or electric fields in materials on the nanometre scale, is a powerful tool for the study of fundamental issues in physics as well as the characterization of advanced materials. This paper presents an overview of recent electron holography studies on advanced magnetic materials, which include hard magnetic materials (both nucleation-type and pinning-type magnets), soft magnetic materials (both classical alloys and recently developed nanostructured materials), magnetic recording materials (Co-CoO tape and other related topics) and magnetic functional materials (ferromagnetic shape memory alloys and colossal magnetoresistive manganites).

  3. DFT calculations for the high-temperature structure of (EDO-TTF)2PF6: Identification of an electronic molecular dimer

    Science.gov (United States)

    Iwano, Kaoru; Shimoi, Yukihiro

    2009-02-01

    Density-functional theory (DFT) calculations are performed based on the high-temperature structure of (EDO-TTF)2PF6, a quasi-one-dimensional molecular compound that shows both thermal and photoinduced phase transitions. In this structure, the EDO-TTF molecules are one-dimensionally aligned, accompanied with weak dimerization. Contrary to a common sense, our DFT calculations reveal that the pair having a shorter mutual distance has a weaker intermolecular coupling than the pair with a longer one; the latter is appropriate to be called an electronic dimer. We also estimate the corresponding transfer energies and discuss their relevance to spin correlations and optical excitations.

  4. Cooling of Electronics with Phase Change Materials

    Science.gov (United States)

    Saha, S. K.; Dutta, P.

    2010-10-01

    This paper deals with phase change materials (PCMs), used in conjunction with thermal conductivity enhancer (TCE), as means of thermal management of electronic systems. This work was motivated by the need for short term thermal management of high packing density equipments (such as in avionics). Eicosane is used as PCM, while aluminium pin or plate fins are used as TCE. The test section considered in all cases is 42×42 mm square base with TCE height of 25 mm. An electronic heater producing 4, 6 and 8 W was used to simulate the heat generation of electronic chips. Various volumetric percentages of TCE in the conglomerate of PCM and TCE were considered, namely, 0, 2, 8, 18 and 27%. The case with 8% volumetric percentage of TCE was found to have the best thermal performance. A numerical model was developed to enable interpretation of experimental results and to perform parametric studies.

  5. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  6. Strong Electron Correlation in the High-Temperature Phase of (EDO-TTF)2PF6 as a Quasi-One-Dimensional Molecular Conductor

    Science.gov (United States)

    Iwano, Kaoru; Shimoi, Yukihiro

    2010-10-01

    We focus on the electronic property of the high-temperature phase of (EDO-TTF)2PF6. Applying a cluster-based density-functional theory (DFT) calculation augmented by a self-consistent environment, we recognize a strong electron-electron repulsion in a dimer-Mott-type ground state. On the basis of this ground state, we obtain an absorption spectrum that takes a form of a single peak in the mid-infrared (mid-IR) region. We next analyze a Hubbard model with alternate transfers, of which the values are determined by the DFT calculations. The obtained absorption peak energy is comparable to the mid-IR peak energy observed in the experiment. Finally, we also investigate other one-dimensional conductors, (TMTSF)2PF6 and (TMTTF)2PF6, which are known as correlated metals, and conclude that (EDO-TTF)2PF6 also falls in this category, in spite of its unique (0110)-type charge ordering observed in the low-temperature phase.

  7. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

    2015-03-24

    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  8. Advanced materials for thermal management of electronic packaging

    CERN Document Server

    Tong, Xingcun Colin

    2011-01-01

    The need for advanced thermal management materials in electronic packaging has been widely recognized as thermal challenges become barriers to the electronic industry's ability to provide continued improvements in device and system performance. With increased performance requirements for smaller, more capable, and more efficient electronic power devices, systems ranging from active electronically scanned radar arrays to web servers all require components that can dissipate heat efficiently. This requires that the materials have high capability of dissipating heat and maintaining compatibility

  9. High temperature superconductivity: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Bedell, K.S.; Coffey, D. (Los Alamos National Lab., NM (USA)); Meltzer, D.E. (Florida Univ., Gainesville, FL (USA)); Pines, D. (Illinois Univ., Urbana, IL (USA)); Schrieffer, J.R. (California Univ., Santa Barbara, CA (USA)) (eds.)

    1990-01-01

    This book is the result of a symposium at Los Alamos in 1989 on High Temperature Superconductivity. The topics covered include: phenomenology, quantum spin liquids, spin space fluctuations in the insulating and metallic phases, normal state properties, and numerical studies and simulations. (JF)

  10. Life at High Temperatures

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 9. Life at High Temperatures. Ramesh Maheshwari. General Article Volume 10 Issue 9 September 2005 pp 23-36. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/010/09/0023-0036. Keywords.

  11. Temperature Effects on The Electrical Characteristics of In0.15Ga0.85As Pseudomorphic High-Electron-Mobility Transistors

    Directory of Open Access Journals (Sweden)

    BECHLAGHEM Fatima Zohra

    2017-10-01

    Full Text Available Nowadays, GaAs-based HEMTs and pseudomorphic HEMTs are speedily replacing conventional MESFET technology in military and commercial applications including, communication, radar and automotive technologies having need of high gain, and low noise figures especially at millimeter-wave frequencies. In this work, a short gate length pseudomorphic HEMT "p-HEMT" on GaAs substrate is treated. As temperature dependence study is a very important part of the complete characterization on active devices, the impact of temperature variation on the electrical properties of our 30nm short gate length pseudomorphic high-electron mobility In0.15Ga0.85As device is investigated. All our static DC device characteristics and RF response have been obtained using a device simulator that is Silvaco software to examine temperature impact on our device output current, transconductance and cutoff frequency. The 30nm gate pseudomorphic HEMT reported here exhibit superior DC and RF performances, Our results reveals a maximum drain-source current IDS up to 537.16 mA/mm, a peak extrinsic transconductance Gm of 345.4 mS/mm, a cutoff frequency Ft of 285.9 GHz, and a maximum frequency Fmax of 1580 GHz at room temperature.

  12. A model for high temperature creep of single crystal superalloys based on nonlocal damage and viscoplastic material behavior

    Science.gov (United States)

    Trinh, B. T.; Hackl, K.

    2014-07-01

    A model for high temperature creep of single crystal superalloys is developed, which includes constitutive laws for nonlocal damage and viscoplasticity. It is based on a variational formulation, employing potentials for free energy, and dissipation originating from plasticity and damage. Evolution equations for plastic strain and damage variables are derived from the well-established minimum principle for the dissipation potential. The model is capable of describing the different stages of creep in a unified way. Plastic deformation in superalloys incorporates the evolution of dislocation densities of the different phases present. It results in a time dependence of the creep rate in primary and secondary creep. Tertiary creep is taken into account by introducing local and nonlocal damage. Herein, the nonlocal one is included in order to model strain localization as well as to remove mesh dependence of finite element calculations. Numerical results and comparisons with experimental data of the single crystal superalloy LEK94 are shown.

  13. Observation of isotropic electron temperature in the turbulent E region

    Directory of Open Access Journals (Sweden)

    S. Saito

    Full Text Available Using EISCAT radar data, we find that electrons are strongly heated in the magnetic field-line direction during high electric field events. The remote site data show that the electron temperature increases in almost the same way in the field-perpendicular direction; electron heating by E region plasma turbulence is isotropic. We discuss the implications of our observation for the "plasmon"-electron as well as the wave Joule heating models of the anomalous electron heating in the E region.

    Key words. Ionosphere (auroral ionosphere; plasma temperature and density; plasma waves and instabilities

  14. Achieving Stable Radiation Pressure Acceleration of Heavy Ions via Successive Electron Replenishment from Ionization of a High-Z Material Coating

    Science.gov (United States)

    Qiao, Bin; Shen, X. F.; Zhang, H.; Kar, S.; Zhou, C. T.; Chang, H. X.; Borghesi, M.; He, X. T.

    2017-10-01

    Among various laser-driven acceleration schemes, radiation pressure acceleration (RPA) is regarded as one of the most promising schemes to obtain high-quality ion beams. Although RPA is very attractive in principle, it is difficult to be achieved experimentally. One of the most important reasons is the dramatic growth of the multi-dimensional Rayleigh-Taylor-like (RT) instabilities. In this talk, we report a novel method to achieve stable RPA of ions from laser-irradiated ultrathin foils, where a high-Z material coating in front is used. The coated high-Z material, acting as a moving electron repository, continuously replenishes the accelerating ion foil with comoving electrons in the light-sail acceleration stage due to its successive ionization under laser fields with Gaussian temporal profile. As a result, the detrimental effects such as electron loss induced by the RT and other instabilities are significantly offset and suppressed so that stable acceleration of ions are maintained. Supported by the NSAF, Grant No. U1630246; the NNSF China Grants No. 11575298; and the National Key Program of S&T Research and Development, Grant No. 2016YFA0401100.

  15. Modeling of Electron Temperature in H- Ion Source

    Science.gov (United States)

    Morishita, Takatoshi; Ogasawara, Masatada; Hatayama, Akiyoshi

    2000-05-01

    The equation of electron temperature is included in a two point numerical code for a high power hydrogen negative ion source. The calculated results of the electron temperature are in good agreement with Japan Atomic Energy Research Institute (JAERI)’s experimental results. The scaling law of electron temperature is estimated as a function of input power and gas pressure. Energy input by arc discharge, energy loss by ionization, dissociation and loss on the wall are considered in the electron energy equation. The leak width on the wall at the cusp magnet is also calculated numerically. Energy loss on the wall is dominant, and is larger than the ionization loss. In a similarly enlarged JAERI’s Kamaboko source, electron density increases and electron temperature decreases under a constant energy input per unit volume. In this situation, H- extraction current increases despite the decrease in H- density because of the enlargement of the H- extraction area.

  16. High Availability Electronics standards

    CERN Document Server

    Larsen, Ray

    2007-01-01

    Availability modeling of the proposed International Linear Collider (ILC) predicts unacceptably low uptime with current electronics systems designs. High Availability (HA) analysis is being used as a guideline for all major machine systems including sources, utilities, cryogenics, magnets, power supplies, instrumentation and controls. R&D teams are seeking to achieve total machine high availability with nominal impact on system cost. The focus of this paper is the investigation of commercial standard HA architectures and packaging for Accelerator Controls and Instrumentation. Application of HA design principles to power systems and detector instrumentation are also discussed.

  17. CaMn(1-x)Nb(x)O3 (x < or = 0.08) perovskite-type phases as promising new high-temperature n-type thermoelectric materials.

    Science.gov (United States)

    Bocher, L; Aguirre, M H; Logvinovich, D; Shkabko, A; Robert, R; Trottmann, M; Weidenkaff, A

    2008-09-15

    Perovskite-type CaMn(1-x)Nb(x)O(3+/-delta) (x = 0.02, 0.05, and 0.08) compounds were synthesized by applying both a "chimie douce" (SC) synthesis and a classical solid state reaction (SSR) method. The crystallographic parameters of the resulting phases were determined from X-ray, electron, and neutron diffraction data. The manganese oxidations states (Mn(4+)/Mn(3+)) were investigated by X-ray photoemission spectroscopy. The orthorhombic CaMn(1-x)Nb(x)O(3+/-delta) (x = 0.02, 0.05, and 0.08) phases were studied in terms of their high-temperature thermoelectric properties (Seebeck coefficient, electrical resistivity, and thermal conductivity). Differences in electrical transport and thermal properties can be correlated with different microstructures obtained by the two synthesis methods. In the high-temperature range, the electron-doped manganate phases exhibit large absolute Seebeck coefficient and low electrical resistivity values, resulting in a high power factor, PF (e.g., for x = 0.05, S(1000K) = -180 microV K(-1), rho(1000K) = 16.8 mohms cm, and PF > 1.90 x 10(-4) W m(-1) K(-2) for 450 K 0.3) make these phases the best perovskitic candidates as n-type polycrystalline thermoelectric materials operating in air at high temperatures.

  18. Electrical, Chemical, And Microstructural Analysis of the Thermal Stability of Nickel-based Ohmic Contacts to Silicon Carbide for High-Temperature Electronics

    Science.gov (United States)

    Virshup, Ariel R.

    With increasing attention on curbing the emission of pollutants into the atmosphere, chemical sensors that can be used to monitor and control these unwanted emissions are in great demand. Examples include monitoring of hydrocarbons from automobile engines and monitoring of flue gases such as CO emitted from power plants. One of the critical limitations in high-temperature SiC gas sensors, however, is the degradation of the metal-SiC contacts over time. In this dissertation, we investigated the high-temperature stability of Pt/TaSix/Ni/SiC ohmic contacts, which have been implemented in SiC-based gas sensors developed for applications in diesel engines and power plants. The high-temperature stability of a Pt/TaSi2/Ni/SiC ohmic contact metallization scheme was characterized using a combination of current-voltage measurements, Auger electron spectroscopy, secondary ion mass spectrometry, and transmission electron microscope imaging and associated analytical techniques. Increasing the thicknesses of the Pt and TaSi2 layers promoted electrical stability of the contacts, which remained ohmic at 600°C in air for over 300 h; the specific contact resistance showed only a gradual increase from an initial value of 5.2 x 10-5 O-cm 2. We observed a continuous silicon-oxide layer in the thinner contact structures, which failed after 36 h of heating. It was found that the interface between TaSix and NiySi was weakened by the accumulation of free carbon (produced by the reaction of Ni and SiC), which in turn facilitated oxygen diffusion from the contact edges. Additional oxygen diffusion occurred along grain boundaries in the Pt overlayer. Meanwhile, thicker contacts, with less interfacial free carbon and enhanced electrical stability contained a much lower oxygen concentration that was distributed across the contact layers, precluding the formation of an electrically insulating contact structure.

  19. High temperature future

    Energy Technology Data Exchange (ETDEWEB)

    Sheinkopf, K. [Solar Energy Research and Education Foundation, Washington, DC (United States)

    1994-09-01

    During the past few years, there have been dramatic accomplishments and success of high temperature solar thermal systems and significant development of these systems. High temperature technologies, about 500 F and higher, such as dish engines, troughs, central receiver power towers and solar process heat systems, have been tested, demonstrated and used in an array of applications, including many cost-effective utility bulk power production and demand side supply projects in the United States. Large systems provide power and hot water to prisons, schools, nursing homes and other institutions. Joint ventures with industry, utility projects, laboratory design assistance and other activities are building a solid industry of US solar thermal systems ready for use today.

  20. Passive electronic identification with temperature monitoring. [Temperature monitor for cattle

    Energy Technology Data Exchange (ETDEWEB)

    Holm, D.M.; Bobbett, R.E.; Koelle, A.R.; Landt, J.A.; Sanders, W.M.; Depp, S.W.; Seawright, G.L.

    1976-01-01

    The United States Department of Agriculture (USDA) and the Energy Research and Development Administration (ERDA) have been supporting an electronic identification and temperature monitoring project at the Los Alamos Scientific Laboratory (LASL) since early 1973. The development, so far, indicates that a subdermally-implanted, electronic transponder (having no batteries) can be remotely activated and transmit temperature and identification information back to a receiver in a few tenths of a second. If this electronic identification and temperature monitoring system is developed into a commercially available product line, and is widely accepted by the cattle industry, it will enable them to carry out more extensive management practices. Better management can result in greater efficiency and productivity. The system will also enable regulatory agencies to trace the movements of diseased animals through commerce, and thus assist in disease control measures. Work so far has been concentrated primarily on determining the technical feasibility of the electronic concepts. (auth)

  1. Electron and Positron Stopping Powers of Materials

    Science.gov (United States)

    SRD 7 NIST Electron and Positron Stopping Powers of Materials (PC database for purchase)   The EPSTAR database provides rapid calculations of stopping powers (collisional, radiative, and total), CSDA ranges, radiation yields and density effect corrections for incident electrons or positrons with kinetic energies from 1 keV to 10 GeV, and for any chemically defined target material.

  2. High-Temperature Superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2012-01-01

    This book presents the current knowledge about superconductivity in high Tc cuprate superconductors. There is a large scientific interest and great potential for technological applications. The book discusses all the aspects related to all families of cuprate superconductors discovered so far. Beginning with the phenomenon of superconductivity, the book covers: the structure of cuprate HTSCs, critical currents, flux pinning, synthesis of HTSCs, proximity effect and SQUIDs, possible applications of high Tc superconductors and theories of superconductivity. Though a high Tc theory is still awaited, this book describes the present scenario and BCS and RVB theories. The second edition was  significantly extended by including film-substrate lattice matching and buffer layer considerations in thin film HTSCs, brick-wall microstructure in the epitaxial films, electronic structure of the CuO2 layer in cuprates, s-wave and d-wave coupling in HTSCs and possible scenarios of theories of high Tc superconductivity.

  3. Elevated-Temperature Tribology of Metallic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL

    2010-01-01

    The wear of metals and alloys takes place in many forms, and the type of wear that dominates in each instance is influenced by the mechanics of contact, material properties, the interfacial temperature, and the surrounding environment. The control of elevated-temperature friction and wear is important for applications like internal combustion engines, aerospace propulsion systems, and metalworking equipment. The progression of interacting, often synergistic processes produces surface deformation, subsurface damage accumulation, the formation of tribolayers, and the creation of free particles. Reaction products, particularly oxides, play a primary role in debris formation and microstructural evolution. Chemical reactions are known to be influenced by the energetic state of the exposed surfaces, and that surface energy is in turn affected by localized deformation and fracture. At relatively low temperatures, work-hardening can occur beneath tribo-contacts, but exposure to high temperatures can modify the resultant defect density and grain structure to affect the mechanisms of re-oxidation. As research by others has shown, the rate of wear at elevated temperatures can either be enhanced or reduced, depending on contact conditions and nature of oxide layer formation. Furthermore, the thermodynamic driving force for certain chemical reactions is moderated by kinetics and microstructure. The role of deformation, oxidation, and tribo-corrosion in the elevated temperature tribology of metallic alloys will be exemplified by three examples involving sliding wear, single-point abrasion, and repetitive impact plus slip.

  4. Rare earth permanent-magnet alloys’ high temperature phase transformation in situ and dynamic observation and its application in material design

    CERN Document Server

    Pan, Shuming

    2013-01-01

    The process of high temperature phase transition of rare earth permanent-magnet alloys is revealed by photographs taken by high voltage TEM. The relationship between the formation of nanocrystal and magnetic properties is discussed in detail, which effects alloys composition and preparation process. The experiment results verified some presumptions, and were valuable for subsequent scientific research and creating new permanent-magnet alloys. The publication is intended for researchers, engineers and managers in the field of material science, metallurgy, and physics. Prof. Shuming Pan is senior engineer of Beijing General Research Institute of Non-ferrous Metal.

  5. Application of High-Temperature Superconducting Thin-Film Devices to Electro-Optical and Electronic Warfare Systems

    Science.gov (United States)

    1990-02-01

    Duzer , and S. E. Schwarz, "A Planar shifters, and circulators. The likeliest form that most of Antenna-Coupled Superconductor-Insulator-Superconductor...34Experimen- 2"T. Van Duzer and C. XV. Turner, Principles of Supqer- I 4’ THL JUj’.\\S HOP~tN. UNNVES TN APPLIED PHYSICS LABORMTORY I A.,REL ARYLANfl I...Electronics Fabrication Facility (15 Sep 1988). "’K. E. Irwin, T. Van Duzer , and S. E. Schwarz, "A 44 U THE JOHNS HOPKINS UNIVERSITY APPLIED

  6. 3D-hybrid material design with electron/lithium-ion dual-conductivity for high-performance Li-sulfur batteries

    Science.gov (United States)

    Zhao, Yan; Tan, Rui; Yang, Jie; Wang, Kai; Gao, Rongtan; Liu, Dong; Liu, Yidong; Yang, Jinlong; Pan, Feng

    2017-02-01

    We report a novel 3D-hybrid cathode material with three-dimensional (3D) N-GO/CNT framework to load sulfur (77.6 wt %), and sulfonated polyaniline (SPANI) of coating layer. Used as a cathode material, it possesses a high capacity (1196 mAh g-1@0.3 A g-1@1.6 mg cm-2), excellent charging-discharging rate (680 mAh g-1@7.5 A g-1) and long-life performance (maintaining 71.1% capacity over 450 cycles), which is mainly attributed to the benefits of excellent electronic/Li-ionic dual-conductivity and confinement effect of the 3D-hybrid N-GO/CNT framework coated by self-doping conducting polymer SPANI. Thus, a 3D sulfur cathode modified with electronic/Li-ionic dual-conduction network can significantly enhance the electrochemical performance and stability, and this novel type of material is very promising for commercial applications that require high energy and power density, long life, and excellent abuse tolerance.

  7. Parametric dependencies of JET electron temperature profiles

    Energy Technology Data Exchange (ETDEWEB)

    Schunke, B. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Imre, K.; Riedel, K. [New York Univ., NY (United States)

    1994-07-01

    The JET Ohmic, L-Mode and H-Mode electron temperature profiles obtained from the LIDAR Thomson Scattering Diagnostic are parameterized in terms of the normalized flux parameter and a set of the engineering parameters like plasma current, toroidal field, line averages electron density... It is shown that the electron temperature profiles fit a log-additive model well. It is intended to use the same model to predict the profile shape for D-T discharges in JET and in ITER. 2 refs., 5 figs.

  8. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  9. Environmental testing techniques for electronics and materials

    CERN Document Server

    Dummer, Geoffrey W A; Fry, D W; Higinbotham, W

    2013-01-01

    Environmental Testing Techniques for Electronics and Materials reviews environmental testing techniques for evaluating the performance of electronic equipment, components, and materials. Environmental test planning, test methods, and instrumentation are described, along with the general environmental conditions under which equipment must operate. This book is comprised of 15 chapters and begins by explaining why environmental testing is necessary and describing the environment in which electronics must operate. The next chapter considers how an environmental test plan is designed; the methods

  10. Amorphous electron-accepting materials for organic optoelectronics

    NARCIS (Netherlands)

    Ganesan, P.

    2007-01-01

    The importance of organic materials for use in electronic devices such as OLEDs, OFETs and photovoltaic cells has increased significantly over the past decade. Organic materials have been attractive candidates for such electronic devices because of their compatibility with high-throughput, low-cost

  11. Measurement of radio wave reflection due to temperature rising from rock salt and ice irradiated by an electron beam for an ultra-high-energy neutrino detector

    Energy Technology Data Exchange (ETDEWEB)

    Tanikawa, Takahiro; Chiba, Masami; Kamijo, Toshio; Yabuki, Fumiaki; Yasuda, Osamu; Akiyama, Hidetoshi; Chikashige, Yuichi; Kon, Tadashi; Shimizu, Yutaka; Utsumi, Michiaki; Fujii, Masatoshi [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji-shi, Tokyo 192-0397 (Japan); Faculty of Science and Technology, Seikei University, Musashino-shi, Tokyo 180-8633 (Japan); Department of Applied Science and Energy Engineering, School of Engineering, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan); School of Medicine, Shimane University, Izumo-shi, Shimane 693-8501 (Japan)

    2012-11-12

    An ultra-high-energy neutrino (UHE{nu}) gives temperature rise along the hadronic and electromagnetic shower when it enters into rock salt or ice. Permittivities of them arise with respect the temperatures at ionization processes of the UHE{nu} shower. It is expected by Fresnel's formula that radio wave reflects at the irregularity of the permittivity in the medium. We had found the radio wave reflection effect in rock salt. The reflection effect and long attenuation length of radio wave in rock salt and ice would yield a new UHE{nu} detection method. An experiment for ice was performed to study the reflection effect. A coaxial tube was filled with rock salt powder or ice. Open end of the coaxial tube was irradiated by a 2 MeV electron beam. Radio wave of 435 MHz was introduced to the coaxial tube. We measured the reflection wave from the open end. We found the radio wave reflection effect due to electron beam irradiation in ice as well as in rock salt.

  12. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High temperature power electronics have become a vital aspect of future designs for power converters in spacecraft, battle zone electric power, satellite power...

  13. Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of High Temperature Composite Materials

    Science.gov (United States)

    Russell, Richard; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

    2011-01-01

    The increased use of high-temperature composite materials in modern and next generation aircraft and spacecraft have led to the need for improved nondestructive evaluation and health monitoring techniques. Such technologies are desirable to improve quality control, damage detection, stress evaluation and temperature measurement capabilities. Novel eddy current sensors and sensor arrays, such as Meandering Winding Magnetometers (MWMs) have provided alternate or complimentary techniques to ultrasound and thermography for both nondestructive evaluation (NDE) and structural health monitoring (SHM). This includes imaging of composite material quality, damage detection and .the monitoring of fiber temperatures and multidirectional stresses. Historically, implementation of MWM technology for the inspection of the Space Shuttle Orbiter Reinforced Carbon-Carbon Composite (RCC) leading edge panels was developed by JENTEK Sensors and was subsequently transitioned by NASA as an operational pre and post flight in-situ inspection at the Kennedy Space Center. A manual scanner, which conformed'automatically to the curvature of the RCC panels was developed and used as a secondary technique if a defect was found during an infrared thermography screening, During a recent proof of concept study on composite overwrapped pressure vessels (COPV's), three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed excellent correlation with actual surface strain gage measurements. Recent advancements of this technology have been made applying MWM sensor technology for scanning COPVs for mechanical damage. This presentation will outline the recent advance in the MWM.technology and the development of MWM techniques for NDE and SHM of carbon wraped composite overwrapped pressure vessels (COPVs) including the measurement of internal stresses via a surface mounted sensor

  14. Nanostructured electronic and magnetic materials

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    analytical chemistry, drug delivery, bioencapsulation, and in electronic, magnetic, optical and mechanical devices. ... The reaction governing electrochromism, which basically is a reversible coloration process under the .... 3.3a Storage applications: The route to progress in memory technology is cost reduction and the ...

  15. Determination of the relative resistance to ignition of selected turbopump materials in high-pressure, high-temperature, oxygen environments, volume 1

    Science.gov (United States)

    Stoltzfus, Joel M.; Benz, Frank J.

    1986-01-01

    Advances in the design of the liquid oxygen, liquid hydrogen engines for the Space Transportation System call for the use of warm, high-pressure oxygen as the driving gas in the liquid oxygen turbopump. The NASA Lewis Research Center requested the NASA White Sands Test Facility (WSTF) to design a test program to determine the relative resistance to ignition of nine selected turbopump materials: Hastelloy X, Inconel 600, Invar 36, Monel K-500, nickel 200, silicon carbide, stainless steel 316, and zirconium copper. The materials were subjected to particle impact and to frictional heating in high-pressure oxygen.

  16. An easy-to-fabricate low-temperature TiO2 electron collection layer for high efficiency planar heterojunction perovskite solar cells

    Directory of Open Access Journals (Sweden)

    B. Conings

    2014-08-01

    Full Text Available Organometal trihalide perovskite solar cells arguably represent the most auspicious new photovoltaic technology so far, as they possess an astonishing combination of properties. The impressive and brisk advances achieved so far bring forth highly efficient and solution processable solar cells, holding great promise to grow into a mature technology that is ready to be embedded on a large scale. However, the vast majority of state-of-the-art perovskite solar cells contains a dense TiO2 electron collection layer that requires a high temperature treatment (>450 °C, which obstructs the road towards roll-to-roll processing on flexible foils that can withstand no more than ∼150 °C. Furthermore, this high temperature treatment leads to an overall increased energy payback time and cumulative energy demand for this emerging photovoltaic technology. Here we present the implementation of an alternative TiO2 layer formed from an easily prepared nanoparticle dispersion, with annealing needs well within reach of roll-to-roll processing, making this technology also appealing from the energy payback aspect. Chemical and morphological analysis allows to understand and optimize the processing conditions of the TiO2 layer, finally resulting in a maximum obtained efficiency of 13.6% for a planar heterojunction solar cell within an ITO/TiO2/CH3NH3PbI3-xClxpoly(3-hexylthiophene/Ag architecture.

  17. Selection of support structure materials for irradiation experiments in the HFIR (High Flux Isotope Reactor) at temperatures up to 500 degrees C

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, K.; Longest, A.W.

    1990-01-01

    The key factor in the design of capsules for irradiation of test specimens in the High Flux Isotope Reactor at preselected temperatures up to 500{degree}C utilizing nuclear heating is a narrow gas-filled gap which surrounds the specimens and controls the transfer of heat from the specimens through the wall of a containment tube to the reactor cooling water. Maintenance of this gap to close tolerances is dependent on the characteristics of the materials used to support the specimens and isolate them from the water. These support structure materials must have low nuclear heating rates, high thermal conductivities, and good dimensional stabilities under irradiation. These conditions are satisfied by certain aluminum alloys. One of these alloys, a powder metallurgy product containing a fine dispersion of aluminum oxide, is no longer manufactured. A new alloys of this type, with the trade name DISPAL, is determined to be a suitable substitute. 23 refs., 13 figs., 3 tabs.

  18. Materials research by electron momentum spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Canney, S.A.; Fang, Z.; Guo, X.; McCarthy, I.E. [Flinders Univ. of South Australia, Adelaide, SA (Australia). Electronic Structure of Materials Centre; Kheifets, A.S.; Vos, M.; Weigold, E. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences and Engineering, Atomic and Molecular Physcis Laboratories

    1998-06-01

    Electron momentum spectroscopy (EMS), also known as (e,2e) spectroscopy is a relatively new technique for the research of materials. It directly determines the electronic structure of materials using binary electron-electron collisions. The measured intensity is proportional to the energy-momentum density, i.e. the modulus square of the wave function in momentum space. This intensity is simply the probability of finding an electron in the material with a particular combination of binding-energy and momentum. In contrast to photoemission measurements, EMS is able to resolve real momentum (rather than crystal-momentum) and the measured intensity is easily related to the electronic structure itself. The measured and calculated momentum densities of graphite, aluminium and amorphous silicon films are presented. 7 refs., 3 figs.

  19. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  20. High temperature phase equilibria and phase diagrams

    CERN Document Server

    Kuo, Chu-Kun; Yan, Dong-Sheng

    2013-01-01

    High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature

  1. Materials for room temperature magnetic refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Rosendahl Hansen, B.

    2010-07-15

    Magnetic refrigeration is a cooling method, which holds the promise of being cleaner and more efficient than conventional vapor-compression cooling. Much research has been done during the last two decades on various magnetic materials for this purpose and today a number of materials are considered candidates as they fulfill many of the requirements for a magnetic refrigerant. However, no one material stands out and the field is still active with improving the known materials and in the search for a better one. Magnetic cooling is based on the magnetocaloric effect, which causes a magnetic material to change its temperature when a magnetic field is applied or removed. For room temperature cooling, one utilizes that the magnetocaloric effect peaks near magnetic phase transitions and so the materials of interest all have a critical temperature within the range of 250 - 310 K. A magnetic refrigerant should fulfill a number of criteria, among these a large magnetic entropy change, a large adiabatic temperature change, preferably little to no thermal or magnetic hysteresis and the material should have the stability required for long term use. As the temperature range required for room temperature cooling is some 40 - 50 K, the magnetic refrigerant should also be able to cover this temperature span either by exhibiting a very broad peak in magnetocaloric effect or by providing the opportunity for creating a materials series with varying transition temperatures. (Author)

  2. History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Larry Zirker; Nathan Jerred; Dr. Indrajit Charit; James Cole

    2012-03-01

    Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.

  3. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material

    OpenAIRE

    Shuailing Ma; Kuo Bao; Qiang Tao; Pinwen Zhu; Teng Ma; Bo Liu; Yazhou Liu; Tian Cui

    2017-01-01

    We synthesized orthorhombic FeB-type MnB (space group: Pnma) with high pressure and high temperature method. MnB is a promising soft magnetic material, which is ferromagnetic with Curie temperature as high as 546.3?K, and high magnetization value up to 155.5?emu/g, and comparatively low coercive field. The strong room temperature ferromagnetic properties stem from the positive exchange-correlation between manganese atoms and the large number of unpaired Mn 3d electrons. The asymptotic Vickers...

  4. Effects of oxygen nonstoichiometry on the high-temperature performance of an yttria-tetragonal zirconia polycrystal material

    Energy Technology Data Exchange (ETDEWEB)

    Swab, J.J.; Katz, R.N.; Starita, C.J. (Army Materials Technology Lab., Watertown, MA (USA))

    1988-05-01

    The hot isostatic pressing of an yttria-tetragonal zirconia polycrystal (Y-TZP) powder yields a body that is slightly reduced. Stepped-temperature stress-rupture tests revealed that a hot isostatically pressed Y-TZP has anomalous time-dependent failure behavior through the temperature range 800{degree} to 1,200{degree}C. However, this anomaly can effectively be eliminated, and the stress-rupture performance significantly improved, by oxidizing the pressed body at 1,000{degree}C before use.

  5. Noncovalent Interactions in Organic Electronic Materials

    KAUST Repository

    Ravva, Mahesh Kumar

    2017-06-29

    In this chapter, we provide an overview of how noncovalent interactions, determined by the chemical structure of π-conjugated molecules and polymers, govern essential aspects of the electronic, optical, and mechanical characteristics of organic semiconductors. We begin by describing general aspects of materials design, including the wide variety of chemistries exploited to control the electronic and optical properties of these materials. We then discuss explicit examples of how the study of noncovalent interactions can provide deeper chemical insights that can improve the design of new generations of organic electronic materials.

  6. Handbook of high-temperature superconductivity theory and experiment

    CERN Document Server

    Brooks, James S

    2007-01-01

    Since the 1980s, a general theme in the study of high-temperature superconductors has been to test the BCS theory and its predictions against new data. At the same time, this process has engendered new physics, new materials, and new theoretical frameworks. Remarkable advances have occurred in sample quality and in single crystals, in hole and electron doping in the development of sister compounds with lower transition temperatures, and in instruments to probe structure and dynamics. Handbook of High-Temperature Superconductvity is a comprehensive and in-depth treatment of both experimental and theoretical methodologies by the the world's top leaders in the field. The Editor, Nobel Laureate J. Robert Schrieffer, and Associate Editor James S. Brooks, have produced a unified, coherent work providing a global view of high-temperature superconductivity covering the materials, the relationships with heavy-fermion and organic systems, and the many formidable challenges that remain.

  7. Investigations into High Temperature Components and Packaging

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  8. Low Temperature Cryocooler Regenerator Materials

    Energy Technology Data Exchange (ETDEWEB)

    K.A. Gschneidner; A.O. Pecharsky; V.K. Pecharsky

    2002-06-27

    There are four important factors which influence the magnitude of the magnetic heat capacity near the magnetic ordering transition temperature. These include the theoretical magnetic entropy, the deGennes factor, crystalline electric field, and the RKKY (Ruderman-Kittel-Kasuya-Yosida) interaction. The lattice contribution to the heat capacity also needs to be considered since it is the sum of the lattice and magnetic contributions which give rise to the heat capacity maxima. The lattice heat capacity depends on the chemical composition, crystal structure and temperature. As a result, one can obtain large changes in the heat capacity maxima by alloying. Several ternary intermetallic systems have been examined in light of these criteria. A number of deviations from the expected behaviors have been found and are discussed.

  9. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  10. Fundamental Processes of Coupled Radiation Damage and Mechanical Behavior in Nuclear Fuel Materials for High Temperature Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Phillpot, Simon; Tulenko, James

    2011-09-08

    The objective of this work has been to elucidate the relationship among microstructure, radiation damage and mechanical properties for nuclear fuel materials. As representative nuclear materials, we have taken an hcp metal (Mg as a generic metal, and Ti alloys for fast reactors) and UO2 (representing fuel). The degradation of the thermo-mechanical behavior of nuclear fuels under irradiation, both the fissionable material itself and its cladding, is a longstanding issue of critical importance to the nuclear industry. There are experimental indications that nanocrystalline metals and ceramics may be more resistant to radiation damage than their coarse-grained counterparts. The objective of this project look at the effect of microstructure on radiation damage and mechanical behavior in these materials. The approach to be taken was state-of-the-art, large-scale atomic-level simulation. This systematic simulation program of the effects of irradiation on the structure and mechanical properties of polycrystalline Ti and UO2 identified radiation damage mechanisms. Moreover, it will provided important insights into behavior that can be expected in nanocrystalline microstructures and, by extension, nanocomposites. The fundamental insights from this work can be expected to help in the design microstructures that are less susceptible to radiation damage and thermomechanical degradation.

  11. Mn-doped TiO2 nanosheet-based spheres as anode materials for lithium-ion batteries with high performance at elevated temperatures.

    Science.gov (United States)

    Zhang, Wei; Zhou, Weidong; Wright, Jasper H; Kim, Young Nam; Liu, Dawei; Xiao, Xingcheng

    2014-05-28

    Novel Mn(2+)-doped TiO2 nanosheet-based spheres have been successfully prepared via a simple hydrothermal and ion-exchange process. After hydrothermal growth, flowerlike nanosheet-based spheres of protonated dititanate were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hierarchical nanostructure was obtained via a dissolution-recrystallization process starting from a precursor of homogenous TiO2 nanospheres. Moreover, as-prepared protonated dititanate was converted to Mn-doped nanosheet-based spheres via the ion-exchange method. Then, both the doped and undoped protonated dititanate were calcined and tested as anode materials for lithium-ion battery applications at elevated temperatures. The undoped sample showed an initial capacity of 201 mAh g(-1) but only had 44.1% of the initial capacity retained after 50 cycles at mixed current densities of 30, 150, and 500 mA g(-1) at 55 °C, while the Mn-doped one exhibited an initial capacity of 190 mAh g(-1) and 91.4% capacity retention with superior reversible capacity under the same test conditions. Comparisons between different samples suggest that manganese ions on the surface of TiO2 nanosheet-based spheres are responsible for the enhanced electrochemical performance.

  12. Crack initiation and crack growth in high temperature materials under cyclic thermal stresses; Rissinitiierung und Risswachstum in Hochtemperaturwerkstoffen unter zyklisch thermischer Beanspruchung

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, C.

    1996-12-01

    The high temperatures of use in drive units, such as the combustion chamber or the hot gas turbine, for example, usually cause high temperature changes. Great temperature differences occur for short periods in the components, and thermal shock is produced. In this work, theoretical and experimental investigations are introduced on crack initiation and crack growth in high temperature materials under cyclic thermal stresses. The experiments were carried out with the inter-metallic phase Ni{sub 3}Al, the nickel-based alloy Nimonic 80A and the iron-based alloy PM 2000 strengthened by oxide dispersion (ODS). A characteristic crack appearance picture was found for each material, which was examined more closely. The stresses occurring in the sample during one cycle were calculated with the aid of the finite element program ABAQUS, knowing the specific material parameters. Based on the linear-elastic fracture mechanics, stress intensity factors were calculated on the superimposition principle. Using the material data from isothermal crack propagation experiments, the prediction of fatigue crack spread with cyclic thermal stresses is compared with the experimental findings. (orig./AKF) [Deutsch] Die hohen Einsatztemperaturen in Antriebsaggregaten wie z.B. der Brennkammer oder der Heissgasturbine bedingen in der Regel hohe Temperaturwechsel. Dabei treten kurzzeitig grosse Temperaturunterschiede in den Bauteilen auf, ein Thermoschock wird erzeugt. In der vorliegenden Arbeit werden theoretische und experimentelle Untersuchungen zur Rissinitiierung und zum Risswachstum in Hochtemperaturwerkstoffen unter zyklisch thermischer Belastung vorgestellt. Die Experimente wurden mit der intermetallischen Phase Ni{sub 3}Al, der Nickelbasislegierung Nimonic 80A und der oxid-dispersionsverfestigten (ODS) Eisenbasislegierung PM2000 durchgefuehrt. Fuer jeden Werkstoff stellte sich ein charakteristisches Risserscheinungsbild dar, das naeher untersucht wurde. Die in der Probe auftretenden

  13. Material Protection During Electron-Beam Welding

    Science.gov (United States)

    Tomlinson, R. L.; Kiluk, F. J.

    1982-01-01

    Alumina pellets behind electron-beam weld joint protect other parts of assembly from beam and from spattered material. Alumina pellets may be cleaned and reused. Easily applied and removed in regions that are narrow or have complex shapes.

  14. Materials support for the development of high temperature advanced furnaces (HITAF): A comparison of selected mechanical properties for three SiC-based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Breder, K.; Tennery, V.J.

    1994-09-01

    Purpose of this project is to compare structural ceramic materials proposed for use in the air heater of a coal fired high temperature advanced furnace (HITAF) for power generation. The work will provide necessary initial strength and statistical material parameters for design of a prototype system. Two teams are currently funded by Pittsburgh Energy Technology Center (PETC) under the Combustion 2000 program to develop such a system. One team is led by the United Technologies Research Corporation, and consists of UTC Turbo Power and Marine Division, Bechtel, Oak Ridge National Laboratory (ORNL) and a Joint Venture of Physical Sciences Inc. (PSI) Technologies, Reaction Engineering International (REI) and University of North Dakota Energy & Environmental Research Center (UNDEERC); the other team is led by Foster Wheeler Development Corporation, and members are AiResearch Division of AlliedSignal Aerospace Systems & Equipment, Research Cottrell, TRW, General Electric and Bechtel.

  15. Modelling of the material flow of Nd-Fe-B magnets under high temperature deformation via finite element simulation method.

    Science.gov (United States)

    Chen, Yen-Ju; Lee, Yen-I; Chang, Wen-Cheng; Hsiao, Po-Jen; You, Jr-Shian; Wang, Chun-Chieh; Wei, Chia-Min

    2017-01-01

    Hot deformation of Nd-Fe-B magnets has been studied for more than three decades. With a good combination of forming processing parameters, the remanence and (BH)max values of Nd-Fe-B magnets could be greatly increased due to the formation of anisotropic microstructures during hot deformation. In this work, a methodology is proposed for visualizing the material flow in hot-deformed Nd-Fe-B magnets via finite element simulation. Material flow in hot-deformed Nd-Fe-B magnets could be predicted by simulation, which fitted with experimental results. By utilizing this methodology, the correlation between strain distribution and magnetic properties enhancement could be better understood.

  16. Electronic Components and Circuits for Extreme Temperature Environments

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad; Dickman, John E.; Gerber, Scott

    2003-01-01

    Planetary exploration missions and deep space probes require electrical power management and control systems that are capable of efficient and reliable operation in very low temperature environments. Presently, spacecraft operating in the cold environment of deep space carry a large number of radioisotope heating units in order to maintain the surrounding temperature of the on-board electronics at approximately 20 C. Electronics capable of operation at cryogenic temperatures will not only tolerate the hostile environment of deep space but also reduce system size and weight by eliminating or reducing the radioisotope heating units and their associate structures; thereby reducing system development as well as launch costs. In addition, power electronic circuits designed for operation at low temperatures are expected to result in more efficient systems than those at room temperature. This improvement results from better behavior and tolerance in the electrical and thermal properties of semiconductor and dielectric materials at low temperatures. The Low Temperature Electronics Program at the NASA Glenn Research Center focuses on research and development of electrical components, circuits, and systems suitable for applications in the aerospace environment and deep space exploration missions. Research is being conducted on devices and systems for reliable use down to cryogenic temperatures. Some of the commercial-off-the-shelf as well as developed components that are being characterized include switching devices, resistors, magnetics, and capacitors. Semiconductor devices and integrated circuits including digital-to-analog and analog-to-digital converters, DC/DC converters, operational amplifiers, and oscillators are also being investigated for potential use in low temperature applications. An overview of the NASA Glenn Research Center Low Temperature Electronic Program will be presented in this paper. A description of the low temperature test facilities along with

  17. Threading dislocation movement in AlGaN/GaN-on-Si high electron mobility transistors under high temperature reverse bias stressing

    Directory of Open Access Journals (Sweden)

    W. A. Sasangka

    2016-09-01

    Full Text Available Dislocations are known to be associated with both physical and electrical degradation mechanisms of AlGaN/GaN-on-Si high electron mobility transistors (HEMTs. We have observed threading dislocation movement toward the gate-edges in AlGaN/GaN-on-Si HEMT under high reverse bias stressing. Stressed devices have higher threading dislocation densities (i.e. ∼5 × 109/cm2 at the gate-edges, as compared to unstressed devices (i.e. ∼2.5 × 109/cm2. Dislocation movement correlates well with high tensile stress (∼1.6 GPa at the gate-edges, as seen from inverse piezoelectric calculations and x-ray synchrotron diffraction residual stress measurements. Based on Peierls stress calculation, we believe that threading dislocations move via glide in 〈 11 2 ¯ 0 〉 / { 1 1 ¯ 00 } and 〈 11 2 ¯ 0 〉 / { 1 1 ¯ 01 } slip systems. This result illustrates the importance of threading dislocation mobility in controlling the reliability of AlGaN/GaN-on-Si HEMTs.

  18. Electron gun control of smart materials

    Science.gov (United States)

    Main, John A.; Nelson, George C.; Martin, Jeffrey W.

    1998-07-01

    Smart material patches are currently an impractical choice in applications requiring fine spatial resolution or control of complex areas. The static nature of electrodes, the conventional choice for control signal application to many smart materials, makes them unsuitable in these instances. To address this issue the use of electron guns as charge sources for smart material control is investigated in this paper. In the electron gun control method the need for separate electrodes and wire leads is eliminated by depositing the control charges directly on the surface of the piezoelectric material. Since piezoelectric materials are dielectrics the charges remain where deposited by the electron gun. The spatial resolution of this control method is as small as the spot size of the electron beam, which in a focused beam can be as small as tens of microns. Large areas can be covered by a single electron gun simply by scanning the beam using deflection plates. Some practical aspects of electron gun control are presented in this paper. A description of an experimental test bed assembled to evaluate electron gun control of PZT-5H is presented, as are results and conceptual models of the system behavior.

  19. Nanoscale high-temperature superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, P.; Wei, J.Y.T.; Ananth, V.; Morales, P.; Skocpol, W

    2004-08-01

    We discuss the exciting prospects of studying high-temperature superconductivity in the nanometer scale from the perspective of experiments, theory and simulation. In addition to enabling studies of novel quantum phases in an unexplored regime of system dimensions and parameters, nanoscale high-temperature superconducting structures will allow exploration of fundamental mechanisms with unprecedented insight. The prospects include, spin-charge separation, detection of electron fractionalization via novel excitations such as vison, stripe states and their dynamics, preformed cooper pairs or bose-condensation in the underdoped regime, and other quantum-ordered states. Towards this initiative, we present the successful development of a novel nanofabrication technique for the epitaxial growth of nanoscale cuprates. Combining the techniques of e-beam lithography and nanomachining, we have been able to fabricate the first generation of high-temperature superconducting nanoscale devices, including Y-junctions, four-probe wires and rings. Their initial transport characterization and scanning tunneling microscopy reveal the integrity of the crystal structure, grown on nanometer scale lateral dimensions. Here, we present atomic force micrographs and electrical characterization of a few nanoscale YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) samples.

  20. Measurement of minute local strain in semiconductor materials and electronic devices by using a highly parallel X-ray microbeam

    CERN Document Server

    Matsui, J; Yokoyama, K; Takeda, S; Katou, M; Kurihara, H; Watanabe, K; Kagoshima, Y; Kimura, S

    2003-01-01

    We have developed an X-ray microbeam with a small angular divergence by adopting X-ray optics with successive use of asymmetric Bragg reflection from silicon crystals for the both polarizations of the synchrotron X-rays. The microbeam actually obtained is several microns in size and possesses an angular divergence of less than 2 arcsec which enables us to measure the strain of 10 sup - sup 5 -10 sup - sup 6. By scanning the sample against the microbeam, distribution of the minute local strain in various regions of semiconductor crystals for electronic devices, e.g., the strain around the SiO sub 2 /Si film edge in silicon devices, the strain in an InGaAsP/InP stripe laser were measured.

  1. Surfaces and interfaces of electronic materials

    CERN Document Server

    Brillson, Leonard J

    2012-01-01

    An advanced level textbook covering geometric, chemical, and electronic structure of electronic materials, and their applications to devices based on semiconductor surfaces, metal-semiconductor interfaces, and semiconductor heterojunctions. Starting with the fundamentals of electrical measurements on semiconductor interfaces, it then describes the importance of controlling macroscopic electrical properties by atomic-scale techniques. Subsequent chapters present the wide range of surface and interface techniques available to characterize electronic, optical, chemical, and structural propertie

  2. Highly efficient perovskite solar cells based on a nanostructured WO3-TiO2 core-shell electron transporting material

    KAUST Repository

    Mahmood, Khalid

    2015-01-01

    Until recently, only mesoporous TiO2 and ZnO were successfully demonstrated as electron transport layers (ETL) alongside the reports of ZrO2 and Al2O3 as scaffold materials in organometal halide perovskite solar cells, largely owing to ease of processing and to high power conversion efficiency. In this article, we explore tungsten trioxide (WO3)-based nanostructured and porous ETL materials directly grown hydrothermally with different morphologies such as nanoparticles, nanorods and nanosheet arrays. The nanostructure morphology strongly influences the photocurrent and efficiency in organometal halide perovskite solar cells. We find that the perovskite solar cells based on WO3 nanosheet arrays yield significantly enhanced photovoltaic performance as compared to nanoparticles and nanorod arrays due to good perovskite absorber infiltration in the porous scaffold and more rapid carrier transport. We further demonstrate that treating the WO3 nanostructures with an aqueous solution of TiCl4 reduces charge recombination at the perovskite/WO3 interface, resulting in the highest power conversion efficiency of 11.24% for devices based on WO3 nanosheet arrays. The successful demonstration of alternative ETL materials and nanostructures based on WO3 will open up new opportunities in the development of highly efficient perovskite solar cells. This journal is © The Royal Society of Chemistry 2015.

  3. Effect of tempering on hardness improvement in a VC/steel surface-alloyed material fabricated by high-energy electron-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Euh, Kwangjun; Kim, Yong Chan; Shin, Keesam; Lee, Sunghak; Kim, Nack J

    2003-04-15

    The present study is concerned with the tempering effect in improving the hardness of a vanadium carbide (VC)/carbon steel surface-alloyed material fabricated by high-energy electron-beam irradiation. The mixture of VC powders and flux (50%MgO-50%CaO) was placed on a plain carbon steel substrate, and then electron beam was irradiated. The surface-alloyed layer of 1.8 mm in thickness was homogeneously formed without defects. The microstructural analysis indicated that coarse VC particles were formed along solidification cell boundaries, and the matrix inside cells was mostly composed of lath-type martensite and fine cuboidal VC particles. A large amount of these VC particles in the lath-type martensitic matrix provided hardness four times greater than that of the substrate. When the VC/steel surface-alloyed material was tempered, fine VC particles precipitated in the tempered martensitic matrix, thereby leading to additional hardness increase. In addition, reduction of residual stress and an increase in fracture toughness could be expected.

  4. Comparison of Reactive and Non-Reactive Spark Plasma Sintering Routes for the Fabrication of Monolithic and Composite Ultra High Temperature Ceramics (UHTC Materials

    Directory of Open Access Journals (Sweden)

    Roberto Orrù

    2013-04-01

    Full Text Available A wider utilization of ultra high temperature ceramics (UHTC materials strongly depends on the availability of efficient techniques for their fabrication as dense bodies. Based on recent results reported in the literature, it is possible to state that Spark Plasma Sintering (SPS technology offers a useful contribution in this direction. Along these lines, the use of two different SPS-based processing routes for the preparation of massive UHTCs is examined in this work. One method, the so-called reactive SPS (R-SPS, consists of the synthesis and densification of the material in a single step. Alternatively, the ceramic powders are first synthesized by Self-propagating High-temperature Synthesis (SHS and then sintered by SPS. The obtained results evidenced that R-SPS method is preferable for the preparation of dense monolithic products, while the sintering of SHS powders requires relatively milder conditions when considering binary composites. The different kinetic mechanisms involved during R-SPS of the monolithic and composite systems, i.e., combustion-like or gradual solid-diffusion, respectively, provides a possible explanation. An important role is also played by the SHS process, particularly for the preparation of composite powders, since stronger interfaces are established between the ceramic constituents formed in situ, thus favoring diffusion processes during the subsequent SPS step.

  5. Probing Amorphous Components in High Temperature TE Materials by in situ Total Scattering and the Pair Distribution Function (PDF) Method

    DEFF Research Database (Denmark)

    Reardon, Hazel; Iversen, Bo Brummerstedt; Blichfeld, Anders Bank

    to heating cycles, then we are closer to distinguishing how we may generate materials that do not undergo specific structure reorientation processes, and/or how we may mitigate them before they occur. Here, we will present a total scattering and PDF study that probes the local structure of the Type......-I clathrate Ba8Ga16Ge30. This suggests that local structure reorientations in the cage are likely to be the root cause of the degradation of the structure. This deepens our understanding of disordered clathrates, and provides evidence that the PDF technique is an effective method for probing local structure...

  6. Electron Density and Temperature Measurements, and Abundance ...

    Indian Academy of Sciences (India)

    Using spectra obtained from the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) spectrograph on the spacecraft SOHO (Solar and Heliospheric Observatory), we investigate the height dependence of electron density, temperature and abundance anomalies in the solar atmosphere. In particular, we present ...

  7. Spectroscopic diagnosis in electronic temperature of photoionise ...

    African Journals Online (AJOL)

    In this work, we are interested in the diagnostics in electronic temperature of a plasma purely photoionized, based on the intensity ration of lines emitted by ions helium-like, which have an atomic number Z relatively small. We considered the three lines corresponding to the transitions starting from the excited levels 1s2l ...

  8. High temperature autoclave vacuum seals

    Science.gov (United States)

    Hoffman, J. R.; Simpson, W. G.; Walker, H. M.

    1971-01-01

    Aluminum sheet forms effective sealing film at temperatures up to 728 K. Soft aluminum wire rings provide positive seal between foil and platen. For applications at temperatures above aluminum's service temperature, stainless steel is used as film material and copper wire as sealant.

  9. Mode-selective thermal radiation from a microsphere as a probe of optical properties of high-temperature materials

    Science.gov (United States)

    Morino, R.; Tajima, H.; Sonoda, H.; Kobayashi, H.; Kanamoto, R.; Odashima, H.; Tachikawa, M.

    2017-06-01

    Our spectroscopic method using laser trapping and heating has demonstrated that thermal emission from a metal oxide microsphere is enhanced at frequencies resonant with the whispering gallery modes of the spherical resonator. Only a mode series of a specific order effectively emits thermal photons, and spectral peaks shift from higher-order whispering gallery modes to fundamental whispering gallery modes as the size parameter decreases. These spectral profiles are analyzed with the Mie scattering theory and a semiclassical rate-equation model. The observed mode selectivity in thermal radiation is attributed to a matching between the rates of cavity damping and internal absorption. Excellent reproducibility of the observed spectral profiles leads to a precise determination of optical constants of extremely hot materials.

  10. Temperature-dependent electronic decay profiles in CZT: probe of bulk and surface properties

    Science.gov (United States)

    Kessick, Royal; Maupin, Hugh; Tepper, Gary C.; Szeles, Csaba

    2003-01-01

    The electronic performance of CZT-based gamma radiation spectrometers is governed by a synergism of bulk and surface properties. Compensation is used to increase the bulk resistivity of Cd1-xZnxTe (x~0.1), but the same electronic states that are introduced to increase the material resistivity can also trap charge and reduce the carrier lifetime. Electrical and mechanical surface defects introduced during or subsequent to crystal harvesting are also known to interfere with device performance. Using a contactless, pulsed laser microwave cavity perturbation technique, electronic decay profiles were studied in high pressure Bridgman CZT as a function of temperature. The electronic decay profile was found to depend very strongly on temperature and was modeled using a function consisting of two exponential terms with temperature-dependent amplitudes and time constants. The model was used to relate the observed temperature dependent decay kinetics in CZT to specific trap energies. It was found that, at low temperatures, the electronic decay process is dominated by a deep trap with an energy of approximately 0.69 +/- 0.1 eV from the band edge. As the temperature is increased, the charge trapping becomes dominated by a second trap with an energy of approximately 0.60 +/- 0.1 eV from the band edge. Surface damage introduces additional charge traps that significantly alter the decay kinetics particularly at low temperatures.

  11. Ion Based High-Temperature Pressure Sensor

    National Research Council Canada - National Science Library

    Zdenek, Jeffrey S; Anthenien, Ralph A

    2004-01-01

    .... The environment encountered in such engines necessitates high temperature and durable (vibration resistant) devices. Traditional pressure sensors can be used, however thermal insulating materials must be used to protect the diaphragm...

  12. Transparent oxide electronics from materials to devices

    CERN Document Server

    Martins, Rodrigo; Barquinha, Pedro; Pereira, Luis

    2012-01-01

    Transparent electronics is emerging as one of the most promising technologies for the next generation of electronic products, away from the traditional silicon technology. It is essential for touch display panels, solar cells, LEDs and antistatic coatings. The book describes the concept of transparent electronics, passive and active oxide semiconductors, multicomponent dielectrics and their importance for a new era of novel electronic materials and products. This is followed by a short history of transistors, and how oxides have revolutionized this field. It concludes with a glance at lo

  13. High Thermal Conductivity Materials

    CERN Document Server

    Shinde, Subhash L

    2006-01-01

    Thermal management has become a ‘hot’ field in recent years due to a need to obtain high performance levels in many devices used in such diverse areas as space science, mainframe and desktop computers, optoelectronics and even Formula One racing cars! Thermal solutions require not just taking care of very high thermal flux, but also ‘hot spots’, where the flux densities can exceed 200 W/cm2. High thermal conductivity materials play an important role in addressing thermal management issues. This volume provides readers a basic understanding of the thermal conduction mechanisms in these materials and discusses how the thermal conductivity may be related to their crystal structures as well as microstructures developed as a result of their processing history. The techniques for accurate measurement of these properties on large as well as small scales have been reviewed. Detailed information on the thermal conductivity of diverse materials including aluminum nitride (AlN), silicon carbide (SiC), diamond, a...

  14. Processing of Bulk YBa2Cu3O(7-x) High Temperature Superconductor Materials for Gravity Modification Experiments and Performance Under AC Levitation

    Science.gov (United States)

    Koczor, Ronald; Noever, David; Hiser, Robert

    1999-01-01

    We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of bulk-processed high temperature superconductor disks. Others have indicated that large annular disks (on the order of 25cm diameter) and AC levitation fields play an essential role in their observed experiments. We report experiments in processing such large bulk superconductors. Successful results depend on material mechanical characteristics, and pressure and heat treat protocols. Annular disks having rough dimensions of 30cm O.D., 7cm I.D. and 1 cm thickness have been routinely fabricated and tested under AC levitation fields ranging from 45 to 300OHz. Implications for space transportation initiatives and power storage flywheel technology will be discussed.

  15. High-resolution electron microscopy

    CERN Document Server

    Spence, John C H

    2013-01-01

    This new fourth edition of the standard text on atomic-resolution transmission electron microscopy (TEM) retains previous material on the fundamentals of electron optics and aberration correction, linear imaging theory (including wave aberrations to fifth order) with partial coherence, and multiple-scattering theory. Also preserved are updated earlier sections on practical methods, with detailed step-by-step accounts of the procedures needed to obtain the highest quality images of atoms and molecules using a modern TEM or STEM electron microscope. Applications sections have been updated - these include the semiconductor industry, superconductor research, solid state chemistry and nanoscience, and metallurgy, mineralogy, condensed matter physics, materials science and material on cryo-electron microscopy for structural biology. New or expanded sections have been added on electron holography, aberration correction, field-emission guns, imaging filters, super-resolution methods, Ptychography, Ronchigrams, tomogr...

  16. Comprehensive inter-laboratory calibration of reference materials for δ18O versus VSMOW using various on-line high-temperature conversion techniques

    Science.gov (United States)

    Brand, Willi A.; Coplen, Tyler B.; Aerts-Bijma, Anita T.; Bohlke, John Karl; Gehre, Matthias; Geilmann, Heike; Groning, Manfred; Jansen, Henk G.; Meijer, Harro A. J.; Mroczkowski, Stanley J.; Qi, Haiping; Soergel, Karin; Stuart-Williams, Hilary; Weise, Stephan M.; Werner, Roland A.

    2009-01-01

    Internationally distributed organic and inorganic oxygen isotopic reference materials have been calibrated by six laboratories carrying out more than 5300 measurements using a variety of high-temperature conversion techniques (HTC) in an evaluation sponsored by the International Union of Pure and Applied Chemistry (IUPAC). To aid in the calibration of these reference materials, which span more than 125‰, an artificially enriched reference water (δ18O of +78.91‰) and two barium sulfates (one depleted and one enriched in 18O) were prepared and calibrated relative to VSMOW2 and SLAP reference waters. These materials were used to calibrate the other isotopic reference materials in this study, which yielded:Reference materialδ18O and estimated combined uncertainty IAEA-602 benzoic acid+71.28 ± 0.36‰USGS35 sodium nitrate+56.81 ± 0.31‰IAEA-NO-3 potassium nitrate+25.32 ± 0.29‰IAEA-601 benzoic acid+23.14 ± 0.19‰IAEA-SO-5 barium sulfate+12.13 ± 0.33‰NBS 127 barium sulfate+8.59 ± 0.26‰VSMOW2 water0‰IAEA-600 caffeine−3.48 ± 0.53‰IAEA-SO-6 barium sulfate−11.35 ± 0.31‰USGS34 potassium nitrate−27.78 ± 0.37‰SLAP water−55.5‰The seemingly large estimated combined uncertainties arise from differences in instrumentation and methodology and difficulty in accounting for all measurement bias. They are composed of the 3-fold standard errors directly calculated from the measurements and provision for systematic errors discussed in this paper. A primary conclusion of this study is that nitrate samples analyzed for δ18O should be analyzed with internationally distributed isotopic nitrates, and likewise for sulfates and organics. Authors reporting relative differences of oxygen-isotope ratios (δ18O) of nitrates, sulfates, or organic material should explicitly state in their reports the δ18O values of two or more internationally distributed nitrates (USGS34, IAEA-NO-3, and USGS35), sulfates (IAEA-SO-5, IAEA

  17. Dual-mode operation of 2D material-base hot electron transistors

    KAUST Repository

    Lan, Yann-Wen

    2016-09-01

    Vertical hot electron transistors incorporating atomically-thin 2D materials, such as graphene or MoS2, in the base region have been proposed and demonstrated in the development of electronic and optoelectronic applications. To the best of our knowledge, all previous 2D material-base hot electron transistors only considered applying a positive collector-base potential (V-CB > 0) as is necessary for the typical unipolar hot-electron transistor behavior. Here we demonstrate a novel functionality, specifically a dual-mode operation, in our 2D material-base hot electron transistors (e.g. with either graphene or MoS2 in the base region) with the application of a negative collector-base potential (V-CB < 0). That is, our 2D material-base hot electron transistors can operate in either a hot-electron or a reverse-current dominating mode depending upon the particular polarity of VCB. Furthermore, these devices operate at room temperature and their current gains can be dynamically tuned by varying VCB. We anticipate our multi-functional dual-mode transistors will pave the way towards the realization of novel flexible 2D material-based high-density and low-energy hot-carrier electronic applications.

  18. Oxide bipolar electronics: materials, devices and circuits

    Science.gov (United States)

    Grundmann, Marius; Klüpfel, Fabian; Karsthof, Robert; Schlupp, Peter; Schein, Friedrich-Leonhard; Splith, Daniel; Yang, Chang; Bitter, Sofie; von Wenckstern, Holger

    2016-06-01

    We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo2O4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization.

  19. Functional organic materials for electronics industries

    Science.gov (United States)

    Shibayama, K.; Ono, H.

    1982-01-01

    Topics closely related with organic, high molecular weight material synthesis are discussed. These are related to applications such as display, recording, sensors, semiconductors, and I.C. correlation. New materials are also discussed. General principles of individual application are not included. Materials discussed include color, electrochromic, thermal recording, organic photoconductors for electrophotography, and photochromic materials.

  20. Materials and applications of bioresorbable electronics

    Science.gov (United States)

    Huang, Xian

    2018-01-01

    Bioresorbable electronics is a new type of electronics technology that can potentially lead to biodegradable and dissolvable electronic devices to replace current built-to-last circuits predominantly used in implantable devices and consumer electronics. Such devices dissolve in an aqueous environment in time periods from seconds to months, and generate biological safe products. This paper reviews materials, fabrication techniques, and applications of bioresorbable electronics, and aims to inspire more revolutionary bioresorbable systems that can generate broader social and economic impact. Existing challenges and potential solutions in developing bioresorbable electronics have also been presented to arouse more joint research efforts in this field to build systematic technology framework. Project supported by the National Natural Science Foundation of China (No. 61604108) and the Natural Science Foundation of Tianjin (No. 16JCYBJC40600).