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Sample records for temperature ltt materials

  1. Transformation behaviour and residual stresses in welding of new LTT filler materials; Umwandlungsverhalten und Eigenspannungen beim Schweissen neuartiger LTT-Zusatzwerkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Kromm, Arne

    2011-07-06

    is seen to occur. This is observed for the considered alloys to be particularly pronounced in transverse direction of the weld. By contrast, the residual stress level in longitudinal weld direction is nearly independent of the shrinkage conditions. With the help of residual stress depth gradients it could be established that the additional shrinkage restraint manifests itself in a parallel shift of the residual stress level in the weld metal. Application of energy-dispersive diffraction methods additionally allowed it for the first time to determine residual stresses in the austenitic phase of the LTT alloy which is present parallel to martensite. Results gained under laboratory conditions mostly need to be verified under real fabrication conditions. For this purpose, a component weld test was performed in a special large-scale testing facility. Under structural shrinkage restraint, the load relieving effect of a specific LTT welding filler material could be proven by means of a pronounced stress reduction duringwelding. Overall, evidence was furnished that the concept of Low Transformation Temperature (LTT)alloys is successful and that the proven austenite-martensite transformation exerts a significanteffect on the residual stress level. [German] Die Erkenntnis, dass die Phasenumwandlung bei der Schweisseigenspannungsentstehung hochfester Staehle eine bedeutende Rolle spielt, gibt es bereits seit langer Zeit. Bisher existierten jedoch keine Ansaetze, diesen Effekt praktisch zur Schweisseigenspannungskontrolle zu nutzen. Neuartige Low Transformation Temperature (LTT) Legierungen bieten aufgrund ihrer charakteristischen chemischen Zusammensetzung die Moeglichkeit, hochfeste Staehle auf deren Festigkeitsniveau zu fuegen. Die martensitische Phasenumwandlung soll zudem eine gezielte Einstellung der Schweisseigenspannungen erlauben. Die im Schrifttum vorliegenden Untersuchungen zu diesem Thema sind zwar zahlreich, bieten jedoch nur wenige Erkenntnisse zur Wechselwirkung

  2. Formation of welding residual stresses in low transformation temperature (LTT materials Tensões residuais de soldagem em materias de baixa temperatura de transformação (BTT

    Directory of Open Access Journals (Sweden)

    Thomas Kannengiesser

    2009-03-01

    Full Text Available For the safety and cost efficiency of welded high-strength steel structures, precise knowledge of the level and distribution of welding- and cooling-specific stresses and residual stresses is essential, since they exert a decisive influence on strength, crack resistance, and finally on the bearable service load. This paper presents innovative filler materials, of which the phase transformation temperature was deliberately adjusted via the chemical composition. The transformation behaviour of these martensitic Low Transformation Temperature (LTT- filler materials shows direct effects on the local residual stresses in the weld and the HAZ. These effects can purposefully be exploited to counteract the thermally induced shrinkage of the material and to produce significant compressive residual stresses in the weld. Comparative welding experiments were carried out on 690 MPa high-strength base materials using various LTT-filler materials. High energy synchrotron radiation was used for residual stress measurement. Particularly the use of high energy synchrotron radiation makes it possible to detect the residual stress condition fast without destruction of material. Thereby, residual stress depth gradients can be determined simultaneously without removing material. In steel, gradients of up to 150 µm can be resolved in such a way. Furthermore, the application of high energy radiation permits determination of residual stresses of any available residual austenite contents. Results show significant dependence of transformation temperatures on the resulting residual stress level and distribution.Para a segurança e eficiência do custo de estruturas soldadas de aço de alta resistência, um conhecimento preciso do nível e distribuição das tensões residuais de soldagem é essencial pois estas exercem uma influência decisiva na resistência à fissuração e na carga suportada em serviço. Este artigo apresenta metais de adição inovativos nos quais a

  3. In-situ-phase analysis using synchrotron radiation of low transformation temperature (LTT welding material Análise "In-Situ" de fases com radiação sincrótona de materiais de soldagem de baixa temperatura de transformação

    Directory of Open Access Journals (Sweden)

    Arne Kromm

    2009-03-01

    Full Text Available Cold cracking resistance is a relevant evaluation criterion for welded joints and affected by residual stresses which result from the welding procedure. Compressive residual stresses can thereby have a positive influence on preventing cracking. A unique possibility of generating compressive residual stresses already during the welding procedure is offered by the so-called Low Transformation Temperature (LTT filler wires. Compared to conventional wires, these materials show decreased phase transformation temperatures which can work against the cooling-specific contraction. In consequence, distinct compressive residual stresses can be observed within the weld and adjacent areas. The strength of these fillers makes them potentially applicable to high-strength steel welding. Investigations were carried out to determine the phase transformation behaviour of different LTT-filler materials. Transformation temperatures were identified using Single Sensor Differential Thermal Analysis (SS-DTA. Additionally Synchrotron radiation was used to measure the transformation kinetics of all involved crystalline phases during heating and cooling of a simulated weld thermal cycle.Fissuração a frio é um critério de avaliação relevante para juntas soldadas, sendo afetada pelas tensões residuais resultantes da soldagem. Neste contexto, tensões residuais de compressão podem ter uma influência positiva no sentido de prevenir a fissuração. Uma possibilidade única de já gerar tensões residuais de compressão já durante a execução da soldagem é oferecida pelos materiais de adição conhecidos como de "baixa temperatura de transformação" (BTT. Comparados com metais de adição convencionais, esses apresentam uma temperatura de transformação de fase inferior a qual pode contrapor a contração térmica do material durante o seu resfriamento. Como resultado, claras tensões residuais compressivas podem ser observadas na soldas e áreas adjacentes. A

  4. nLTT R package

    NARCIS (Netherlands)

    Janzen, Thijs; Bilderbeek, Richèl

    2016-01-01

    The nLTT statistic is a likelihood free summary statistic to compare the similarity between two phylogenetic trees. It calculates the distance between the lineage through time curves of the two trees, after normalizing the lineage through time curves with respect to the maximum number of lineages

  5. 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.)

  6. 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 ...

  7. 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...

  8. 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.)

  9. 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.

  10. 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.

  11. 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...

  12. 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)

  13. 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

  14. 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.

  15. Comparison of CFD simulations to non-rotating MEXICO blades experiment in the LTT wind tunnel of TUDelft

    NARCIS (Netherlands)

    Zhang, Y.; Van Zuijlen, A.; Van Bussel, G.

    2014-01-01

    In this paper, three dimensional flow over non-rotating MEXICO blades is simulated by CFD methods. The numerical results are compared with the latest MEXICO wind turbine blades measurements obtained in the low speed low turbulence (LTT) wind tunnel of Delft University of Technology. This study aims

  16. Full Scale Test of SSP 34m blade, edgewise loading LTT

    DEFF Research Database (Denmark)

    Nielsen, Magda; Jensen, Find Mølholt; Nielsen, Per Hørlyk

    as well. The blade has been submitted to thorough examination. More areas have been examined with DIC, both global and local deflections have been measured, and also 378 strain gauge measurements have been performed. Furthermore Acoustic Emission has been used in order to detect damage while testing new...... load areas. The global deflection is compared with results from a previous test and results from FEM analyses in order to validate the solution as to how the gravity load on the blade was handled. Furthermore, the DIC measurement and the displacement sensors measurements are compared in order......This report is a part of the research project “Eksperimentel vingeforskning: Strukturelle mekanismer i nutidens og fremtidens store vinger under kombineret last” where a 34m wind turbine blade from SSP-Technology A/S has been tested in edgewise direction (LTT). The applied load is 60...

  17. The Lunar Transit Telescope (LTT) - An early lunar-based science and engineering mission

    Science.gov (United States)

    Mcgraw, John T.

    1992-01-01

    The Sentinel, the soft-landed lunar telescope of the LTT project, is described. The Sentinel is a two-meter telescope with virtually no moving parts which accomplishes an imaging survey of the sky over almost five octaves of the electromagnetic spectrum from the ultraviolet into the infrared, with an angular resolution better than 0.1 arsec/pixel. The Sentinel will incorporate innovative techniques of interest for future lunar-based telescopes and will return significant engineering data which can be incorporated into future lunar missions. The discussion covers thermal mapping of the Sentinel, measurement of the cosmic ray flux, lunar dust, micrometeoroid flux, the lunar atmosphere, and lunar regolith stability and seismic activity.

  18. 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.

  19. 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

  20. Phase change material for temperature control and material storage

    Science.gov (United States)

    Wessling, Jr., Francis C. (Inventor); Blackwood, James M. (Inventor)

    2011-01-01

    A phase change material comprising a mixture of water and deuterium oxide is described, wherein the mole fraction of deuterium oxide is selected so that the mixture has a selected phase change temperature within a range between 0.degree. C. and 4.degree. C. The mixture is placed in a container and used for passive storage and transport of biomaterials and other temperature sensitive materials. Gels, nucleating agents, freezing point depression materials and colorants may be added to enhance the characteristics of the mixture.

  1. 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

  2. Materials for Room Temperature Magnetic Refrigeration

    DEFF Research Database (Denmark)

    Hansen, Britt Rosendahl

    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 considere...... 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.......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...

  3. Cutting temperature measurement and material machinability

    Directory of Open Access Journals (Sweden)

    Nedić Bogdan P.

    2014-01-01

    Full Text Available Cutting temperature is very important parameter of cutting process. Around 90% of heat generated during cutting process is then away by sawdust, and the rest is transferred to the tool and workpiece. In this research cutting temperature was measured with artificial thermocouples and question of investigation of metal machinability from aspect of cutting temperature was analyzed. For investigation of material machinability during turning artificial thermocouple was placed just below the cutting top of insert, and for drilling thermocouples were placed through screw holes on the face surface. In this way was obtained simple, reliable, economic and accurate method for investigation of cutting machinability.

  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. 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

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Full Scale Test SSP 34m blade, edgewise loading LTT. Extreme load and PoC_InvE Data report

    DEFF Research Database (Denmark)

    Nielsen, Magda; Roczek-Sieradzan, Agnieszka; Jensen, Find Mølholt

    in edgewise direction (LTT). The blade has been submitted to thorough examination by means of strain gauges, displacement transducers and a 3D optical measuring system. This data report presents results obtained during full scale testing of the blade up to 80% Risø load, where 80% Risø load corresponds to 100......% certification load. These pulls at 80% Risø load were repeated and the results from these pulls were compared. The blade was reinforced according to a Risø DTU invention, where the trailing edge panels are coupled. The coupling is implemented to prevent the out of plane deformations and to reduce peeling...

  11. 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

  12. 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.

  13. 49 CFR 172.325 - Elevated temperature materials.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Elevated temperature materials. 172.325 Section... REQUIREMENTS, AND SECURITY PLANS Marking § 172.325 Elevated temperature materials. (a) Except as provided in paragraph (b) of this section, a bulk packaging containing an elevated temperature material must be marked...

  14. Constraints on the Adiabatic Temperature Change in Magnetocaloric Materials

    DEFF Research Database (Denmark)

    Nielsen, Kaspar Kirstein; Bahl, Christian Robert Haffenden; Smith, Anders

    2010-01-01

    The thermodynamics of the magnetocaloric effect implies constraints on the allowed variation in the adiabatic temperature change for a magnetocaloric material. An inequality for the derivative of the adiabatic temperature change with respect to temperature is derived for both first- and second......-order materials. For materials with a continuous adiabatic temperature change as a function of temperature, this inequality is shown to hold for all temperatures. However, discontinuous materials may violate the inequality. We compare our results with measured results in the literature and discuss...

  15. 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...

  16. 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.

  17. 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....

  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 failure to meet the...

  19. 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...

  20. 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...

  1. A novel magnetic valve using room temperature magnetocaloric materials

    DEFF Research Database (Denmark)

    Eriksen, Dan; Bahl, Christian; Pryds, Nini

    2012-01-01

    Magnetocaloric materials with near-room-temperature tuneable Curie temperatures have been utilized to develop a novel magnetic valve technology. The temperature dependent attractive force between the materials and a permanent magnet assembly is used to actuate valves as a response to temperature...... changes. This is made possible by the strong temperature dependence of the magnetization close to the Curie temperature of the magnetocaloric materials. Different compositions of both La0.67(Ca,Sr)0.33MnO3 and La(Fe,Co,Si)13 have been considered for use in prototype valves. Based on measured magnetization...... data a 3D finite element model has been set up to calculate the magnetic force between (graded) blocks of these materials and a permanent magnet assembly. The results have been used to calculate equilibrium points for actuation systems where the magnetic force is balanced by a spring force...

  2. Comparison of CFD simulations to non-rotating MEXICO blades experiment in the LTT wind tunnel of TUDelft

    Science.gov (United States)

    Zhang, Ye; van Zuijlen, Alexander; van Bussel, Gerard

    2014-06-01

    In this paper, three dimensional flow over non-rotating MEXICO blades is simulated by CFD methods. The numerical results are compared with the latest MEXICO wind turbine blades measurements obtained in the low speed low turbulence (LTT) wind tunnel of Delft University of Technology. This study aims to validate CFD codes by using these experimental data measured in well controlled conditions. In order to avoid use of wind tunnel corrections, both the blades and the wind tunnel test section are modelled in the simulations. The ability of Menter's k - ω shear stress transport (SST) turbulence model is investigated at both attached flow and massively separated flow cases. Steady state Reynolds averaged Navier Stokes (RANS) equations are solved in these computations. The pressure distribution at three measured sections are compared under the conditions of different inflow velocities and a range of angles of attack. The comparison shows that at attached flow condition, good agreement can be obtained for all three airfoil sections. Even with massively separated flow, still fairly good pressure distribution comparison can be found for the DU and NACA airfoil sections, although the RISØ section shows poor comparison. At the near stall case, considerable deviations exists on the forward half part of the upper surface for all three sections.

  3. Temperature Measurement of a Glass Material Using a Multiwavelength Pyrometer

    Science.gov (United States)

    Ng, Daniel

    1997-01-01

    Temperature measurement of a substance that is transparent using the traditional 1-color, 2-color and other pyrometers has been difficult. The radiation detected by pyrometers do not come from a well defined location in the transparent body. The multiwavelength pyrometer developed at the NASA Lewis Research Center can measure the surface temperature of many materials. We show in this paper that it also measures the surface and a bulk subsurface temperature of transparent materials like glass.

  4. Research of fuel temperature control in fuel pipeline of diesel engine using positive temperature coefficient material

    Directory of Open Access Journals (Sweden)

    Xiaolu Li

    2016-01-01

    Full Text Available As fuel temperature increases, both its viscosity and surface tension decrease, and this is helpful to improve fuel atomization and then better combustion and emission performances of engine. Based on the self-regulated temperature property of positive temperature coefficient material, this article used a positive temperature coefficient material as electric heating element to heat diesel fuel in fuel pipeline of diesel engine. A kind of BaTiO3-based positive temperature coefficient material, with the Curie temperature of 230°C and rated voltage of 24 V, was developed, and its micrograph and element compositions were also analyzed. By the fuel pipeline wrapped in six positive temperature coefficient ceramics, its resistivity–temperature and heating characteristics were tested on a fuel pump bench. The experiments showed that in this installation, the surface temperature of six positive temperature coefficient ceramics rose to the equilibrium temperature only for 100 s at rated voltage. In rated power supply for six positive temperature coefficient ceramics, the temperature of injection fuel improved for 21°C–27°C within 100 s, and then could keep constant. Using positive temperature coefficient material to heat diesel in fuel pipeline of diesel engine, the injection mass per cycle had little change, approximately 0.3%/°C. This study provides a beneficial reference for improving atomization of high-viscosity liquids by employing positive temperature coefficient material without any control methods.

  5. 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

  6. 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

  7. Temperature Measurement of Ceramic Materials Using a Multiwavelength Pyrometer

    Science.gov (United States)

    Ng, Daniel; Fralick, Gustave

    1999-01-01

    The surface temperatures of several pure ceramic materials (alumina, beryllia, magnesia, yittria and spinel) in the shape of pellets were measured using a multiwavelength pyrometer. In one of the measurements, radiation signal collection is provided simply by an optical fiber. In the other experiments, a 4.75 inch (12 cm) parabolic mirror collects the signal for the spectrometer. Temperature measurement using the traditional one- and two-color pyrometer for these ceramic materials is difficult because of their complex optical properties, such as low emissivity which varies with both temperature and wavelength. In at least one of the materials, yittria, the detected optical emission increased as the temperature was decreased due to such emissivity variation. The reasons for such changes are not known. The multiwavelength pyrometer has demonstrated its ability to measure surface temperatures under such conditions. Platinum electrodes were embedded in the ceramic pellets for resistance measurements as the temperature changed.

  8. Instrument for Measuring Thermal Conductivity of Materials at Low Temperatures

    Science.gov (United States)

    Fesmire, James; Sass, Jared; Johnson, Wesley

    2010-01-01

    With the advance of polymer and other non-metallic material sciences, whole new series of polymeric materials and composites are being created. These materials are being optimized for many different applications including cryogenic and low-temperature industrial processes. Engineers need these data to perform detailed system designs and enable new design possibilities for improved control, reliability, and efficiency in specific applications. One main area of interest is cryogenic structural elements and fluid handling components and other parts, films, and coatings for low-temperature application. An important thermal property of these new materials is the apparent thermal conductivity (k-value).

  9. Effect of outgassing temperature on the performance of porous materials

    Science.gov (United States)

    Figini-Albisetti, Alessandro; Velasco, Leticia F.; Parra, José B.; Ania, Conchi O.

    2010-06-01

    This work illustrates the consequences of an inadequate outgassing temperature of porous materials of different nature (zeolites and activated carbons) on their performance on gas storage and wastewater remediation. Outgassing at low temperature in thermally stable materials leads to an incomplete cleaning of the porous surface; as a result, the gas storage ability based on adsorption isotherms is underestimated. In contrast, outgassing at elevated temperature in temperature-sensitive materials provokes irreversible changes in their composition and structure, which also affects strongly their stability and performance. Two examples illustrating wrong interpretation data on CO 2 capture on zeolites and wastewater treatment using activated carbons are addressed. The results show how the performance of a given material can be significantly modified or misunderstood after the outgassing pretreatment.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Utilizing Materials With Controllable Curie Temperatures for Magnetic Actuation Purposes

    DEFF Research Database (Denmark)

    Eriksen, Dan; Bahl, Christian R.H.; Smith, Anders

    2013-01-01

    The magnetic force between a permanent magnet and different blocks of ferromagnetic materials was measured and calculated as a function of distance and temperature in the vicinity of the Curie temperature of the materials. The calculations were carried out using a 3-D finite-element model...... of the system. On the basis of forces predicted by the model a number of equilibrium points were calculated for a system where the magnetic force on a ferromagnetic block of material is balanced by a linear spring force. It is shown how these calculation procedures can be used as a tool for designing autonomous...

  15. 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.

  16. BUCKLING OF A COLUMN WITH TEMPERATURE DEPENDENT MATERIAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Ömer SOYKASAP

    2001-01-01

    Full Text Available Buckling of a column with temperature dependent material properties is investigated. Euler-Bernoulli theory of thin beams is used to derive the element matrices by means of the minimum potential energy principle. Temperature dependency of material properties is taken into account in the formulation. The column is divided into finite elements with the axial degrees of freedom defined at the outer fiber of the column. Column elements have simpler derivations and compact element matrices than those of classical beam-bending element. Some illustrative examples are presented to show the convergence of numerical results obtained by the use of new elements. The results are compared with those of the classical beam-bending element and analytical solution. The new element converges to the analytical results as powerful as the classical beam-bending element. The temperature effects on the buckling loads of the column with temperature dependent material properties are also examined.

  17. Temperature-regulated guest admission and release in microporous materials

    Science.gov (United States)

    Li, Gang (Kevin); Shang, Jin; Gu, Qinfen; Awati, Rohan V.; Jensen, Nathan; Grant, Andrew; Zhang, Xueying; Sholl, David S.; Liu, Jefferson Z.; Webley, Paul A.; May, Eric F.

    2017-06-01

    While it has long been known that some highly adsorbing microporous materials suddenly become inaccessible to guest molecules below certain temperatures, previous attempts to explain this phenomenon have failed. Here we show that this anomalous sorption behaviour is a temperature-regulated guest admission process, where the pore-keeping group's thermal fluctuations are influenced by interactions with guest molecules. A physical model is presented to explain the atomic-level chemistry and structure of these thermally regulated micropores, which is crucial to systematic engineering of new functional materials such as tunable molecular sieves, gated membranes and controlled-release nanocontainers. The model was validated experimentally with H2, N2, Ar and CH4 on three classes of microporous materials: trapdoor zeolites, supramolecular host calixarenes and metal-organic frameworks. We demonstrate how temperature can be exploited to achieve appreciable hydrogen and methane storage in such materials without sustained pressure. These findings also open new avenues for gas sensing and isotope separation.

  18. 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.

  19. 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.

  20. Impact of nesting material on mouse body temperature and physiology.

    Science.gov (United States)

    Gaskill, Brianna N; Gordon, Christopher J; Pajor, Edmond A; Lucas, Jeffrey R; Davis, Jerry K; Garner, Joseph P

    2013-02-17

    In laboratories, mice are housed at 20-24 °C, which is below their lower critical temperature (≈30 °C). Thus, mice are potentially cold stressed, which can alter metabolism, immune function, and reproduction. These physiological changes reflect impaired wellbeing, and affect scientific outcomes. We hypothesized that nesting material would allow mice to alleviate cold stress by controlling their thermal microenvironment, thus insulating them, reducing heat loss and thermogenic processes. Naïve C57BL/6, CD-1, and BALB/c mice (24 male and 24 female/strain in groups of 3) were housed in standard cages at 20 °C either with or without 8 g nesting material for 4 weeks. Core body temperature was followed using intraperitoneal radio telemetry. The thermal properties of the nests were assessed using a thermal imaging camera, and related to nest quality. Higher scoring nests were negatively correlated with the mean radiated temperature and were thus more insulating. No effects of nesting material on body temperature were found. CD-1 mice with nesting material had higher end body weights than controls. No effect was seen in the other two strains. Mice with the telemetry implant had larger spleens than controls, possibly indicating an immune response to the implant or low level infection from the surgery. BALB/c mice express less mRNA for the UCP1 protein than mice without nesting material. This indicates that BALB/c's with nesting material do not utilize their brown fat to create heat as readily as controls. Nests can alleviate thermal discomfort by decreasing the amount of radiated heat and reduce the need for non-shivering thermogenesis. However, different strains appear to use different behavioral (through different primary modes of behavioral thermoregulation) and physiological strategies (utilizing thermogenesis to different degrees) to maintain a constant body temperature under cool standard laboratory ambient temperatures. Copyright © 2013 Elsevier Inc. All

  1. 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.

  2. Low temperature dielectric properties of magnetoplumbite family of materials.

    Energy Technology Data Exchange (ETDEWEB)

    Venkateshwaran, B.; Yao, M.; Guo, R.; Bhalla, A.; Balachandran, U.; Energy Technology; Pennsylvania State Univ.

    1999-01-01

    The magnetoplumbite family of materials exhibit properties that make them suitable to be used as substrates materials for microwave application. Four members of the family studied in this work are LaMgAl{sub 11}O{sub 19}, NdGaMgAl{sub 10}O{sub 19}, CaGa{sub 6}Al{sub 6}O{sub 19} and CaGa{sub 12}O{sub 19}. Dielectric studies have been carried out over a temperature range of 4-300 K and a wide frequency range. All four exhibit a low dielectric constant with good temperature stability, low dielectric loss and favorable frequency dependence characteristics.

  3. Experimental Observations on Material Damping at Cryogenic Temperatures

    Science.gov (United States)

    Peng, Chia-Yen; Levine, Marie; Shido, Lillian; Leland, Robert

    2004-01-01

    This paper describes a unique experimental facility designed to measure damping of materials at cryogenic temperatures for the Terrestrial Planet Finder (TPF) mission at the Jet Propulsion Laboratory. The test facility removes other sources of damping in the measurement by avoiding frictional interfaces, decoupling the test specimen from the support system, and by using a non-contacting measurement device. Damping data reported herein are obtained for materials (Aluminum, Aluminum/Terbium/Dysprosium, Titanium, Composites) vibrating in free-free bending modes with low strain levels (< 10(exp -6) ppm). The fundamental frequencies of material samples are ranged from 14 to 202 Hz. To provide the most beneficial data relevant to TPF-like precision optical space missions, the damping data are collected from room temperatures (around 293 K) to cryogenic temperatures (below 40 K) at unevenly-spaced intervals. More data points are collected over any region of interest. The test data shows a significant decrease in viscous damping at cryogenic temperatures. The cryogenic damping can be as low as 10(exp -4) %, but the amount of the damping decrease is a function of frequency and material. However, Titanium 15-3-3-3 shows a remarkable increase in damping at cryogenic temperatures. It demonstrates over one order of magnitude increase in damping in comparison to Aluminum 6061-T6. Given its other properties (e.g., good stiffness and low conductivity) this may prove itself to be a good candidate for the application on TPF. At room temperatures, the test data are correlated well with the damping predicted by the Zener theory. However, large discrepancies at cryogenic temperatures between the Zener theory and the test data are observed.

  4. 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.

  5. Corrosion behavior of construction materials for intermediate temperature steam electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Jensen, Jens Oluf

    2013-01-01

    Different corrosion resistant stainless steels, nickel-based alloys, pure nickel, Ta-coated stainless steel (AISI 316L), niobium, platinum and gold rods were evaluated as possible materials for use in the intermediate temperature (200-400 °C) acidic water electrolysers. The corrosion resistance w...

  6. 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.

  7. 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.

  8. 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

  9. Apparatus for temperature-dependent cathodoluminescence characterization of materials

    Science.gov (United States)

    Bok, Jan; Schauer, Petr

    2014-07-01

    An apparatus for characterization of temperature-dependent cathodoluminescence (CL) of solid-state materials is presented. This device excites a specimen using an electron beam and the CL emission is collected from the specimen side opposite the e-beam irradiation. The design of the temperature-controlled specimen holder that enables cooling down to 100 K and heating up to 500 K is described. The desired specimen temperature is automatically stabilized using a PID controller, which is the proportional-integral-derivative control feedback loop. Moreover, the specimen holder provides in situ e-beam current measurement during the specimen excitation. The apparatus allows the measurement of the CL intensity, the CL spectrum, or the CL intensity decay depending on the specimen temperature, or on a variety of excitation conditions, such as excitation energy, electron current (dose), or excitation duration. The apparatus abilities are demonstrated by an example of the CL measurements of the YAG:Ce single-crystal scintillator.

  10. Temperature-responsive compounds as in situ gelling biomedical materials.

    Science.gov (United States)

    Moon, Hyo Jung; Ko, Du Young; Park, Min Hee; Joo, Min Kyung; Jeong, Byeongmoon

    2012-07-21

    Aqueous solutions that undergo sol-to-gel transition as the temperature increases have been extensively studied during the last decade. The material can be designed by controlling the hydrophilic and hydrophobic balance of the material. Basically, the molecular weight of the hydrophilic block and hydrophobic block of a compound should be fine-tuned from the synthetic point of view. In addition, stereochemistry, microsequence, topology, and nanostructures of the compound also affect the transition temperature, gel window, phase diagram, and modulus of the gel. From a practical point of view, biodegradability, biocompatibility, and interactions between the material and drug or cell should be considered in designing a thermogelling material. The interactions are particularly important in that they control drug release profile and initial burst release of the drug in the drug delivery system, and affect cell proliferation, differentiation, and biomarker expression in three-dimensional cell culture and tissue engineering application. This review provides an in-depth summary of the recent progress of thermogelling systems including polymers, low molecular compounds, and nanoemulsions. Their biomedical applications were also comparatively discussed. In addition, perspectives on future material design of a new thermogelling material and its application are suggested.

  11. 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.

  12. 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.

  13. Temperature-regulated guest admission and release in microporous materials

    Science.gov (United States)

    Li, Gang (Kevin); Shang, Jin; Gu, Qinfen; Awati, Rohan V.; Jensen, Nathan; Grant, Andrew; Zhang, Xueying; Sholl, David S.; Liu, Jefferson Z.; Webley, Paul A.; May, Eric F.

    2017-01-01

    While it has long been known that some highly adsorbing microporous materials suddenly become inaccessible to guest molecules below certain temperatures, previous attempts to explain this phenomenon have failed. Here we show that this anomalous sorption behaviour is a temperature-regulated guest admission process, where the pore-keeping group's thermal fluctuations are influenced by interactions with guest molecules. A physical model is presented to explain the atomic-level chemistry and structure of these thermally regulated micropores, which is crucial to systematic engineering of new functional materials such as tunable molecular sieves, gated membranes and controlled-release nanocontainers. The model was validated experimentally with H2, N2, Ar and CH4 on three classes of microporous materials: trapdoor zeolites, supramolecular host calixarenes and metal-organic frameworks. We demonstrate how temperature can be exploited to achieve appreciable hydrogen and methane storage in such materials without sustained pressure. These findings also open new avenues for gas sensing and isotope separation. PMID:28598429

  14. 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.

  15. 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

  16. 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.

  17. Organic Materials for Time-Temperature Integrator Devices.

    Science.gov (United States)

    Cavallini, Massimiliano; Melucci, Manuela

    2015-08-12

    Time-temperature integrators (TTIs) are devices capable of recording the thermal history of a system. They have an enormous impact in the food and pharmaceutical industries. TTIs exploit several irreversible thermally activated transitions such as recrystallization, dewetting, smoothening, chemical decomposition, and polymorphic transitions, usually considered drawbacks for many technological applications. The aim of this article is to sensitize research groups working in organic synthesis and surface science toward TTI devices, enlarging the prospects of many new materials. We reviewed the principal applications highlighting the need and criticisms of TTIs, which offer a new opportunity for the development of many materials.

  18. 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.

  19. Room temperature Sieving of Hydrogen Isotopes Using 2-D Materials

    Energy Technology Data Exchange (ETDEWEB)

    Hitchcock, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Krentz, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Serkiz, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Velten, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Xiao, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-28

    Hydrogen isotope separation is critical to the DOE’s mission in environmental remediation and nuclear nonproliferation. Isotope separation is also a critical technology for the NNSA, and the ability to perform the separations at room temperature with a relatively small amount of power and space would be a major advancement for their respective missions. Recent work has shown that 2-D materials such as graphene and hexagonal boron nitride can act as an isotopic sieve at room temperature; efficiently separating hydrogen isotopes in water with reported separation ratios of 10:1 for hydrogen: deuterium separation for a single pass. The work performed here suggests that this technique has merit, and furthermore, we are investigating optimization and scale up of the required 2-D material based membranes.

  20. 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...

  1. 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.

  2. 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.

  3. Characterization of Decommissioned PWR Vessel Internals Materials Samples: Material Certification, Fluence, and Temperature (Nonproprietary Version)

    Energy Technology Data Exchange (ETDEWEB)

    M. Krug; R. Shogan; A. Fero; M. Snyder

    2004-11-01

    Pressurized water reactor (PWR) cores, operate under extreme environmental conditions due to coolant chemistry, operating temperature, and neutron exposure. Extending the life of PWRs require detailed knowledge of the changes in mechanical and corrosion properties of the structural austenitic stainless steel components adjacent to the fuel. This report contains basic material characterization information of the as-installed samples of reactor internals material which were harvested from a decommissioned PWR.

  4. 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

  5. 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.

  6. Facesheet Delamination of Composite Sandwich Materials at Cryogenic Temperatures

    Science.gov (United States)

    Gates, Thomas S.; Odegard, Gregory M.; Herring, Helen M.

    2003-01-01

    The next generation of space transportation vehicles will require advances in lightweight structural materials and related design concepts to meet the increased demands on performance. One potential source for significant structural weight reduction is the replacement of traditional metallic cryogenic fuel tanks with new designs for polymeric matrix composite tanks. These new tank designs may take the form of thin-walled sandwich constructed with lightweight core and composite facesheets. Life-time durability requirements imply the materials must safely carry pressure loads, external structural loads, resist leakage and operate over an extremely wide temperature range. Aside from catastrophic events like tank wall penetration, one of the most likely scenarios for failure of a tank wall of sandwich construction is the permeation of cryogenic fluid into the sandwich core and the subsequent delamination of the sandwich facesheet due to the build-up of excessive internal pressure. The research presented in this paper was undertaken to help understand this specific problem of core to facesheet delamination in cryogenic environments and relate this data to basic mechanical properties. The experimental results presented herein provide data on the strain energy release rate (toughness) of the interface between the facesheet and the core of a composite sandwich subjected to simulated internal pressure. A unique test apparatus and associated test methods are described and the results are presented to highlight the effects of cryogenic temperature on the measured material properties.

  7. 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

  8. 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...

  9. Low Temperature Regolith Bricks for In-Situ Structural Material

    Science.gov (United States)

    Grossman, Kevin; Sakthivel, Tamil S.; Mantovani, James; Seal, Sudipta

    2016-01-01

    Current technology for producing in-situ structural materials on future missions to Mars or the moon relies heavily on energy-intensive sintering processes to produce solid bricks from regolith. This process requires heating the material up to temperatures in excess of 1000 C and results in solid regolith pieces with compressive strengths in the range of 14000 to 28000 psi, but are heavily dependent on the porosity of the final material and are brittle. This method is currently preferred over a low temperature cementation process to prevent consumption of precious water and other non-renewable materials. A high strength structural material with low energy requirements is still needed for future colonization of other planets. To fulfill these requirements, a nano-functionalization process has been developed to produce structural bricks from regolith simulant and shows promising mechanical strength results. Functionalization of granular silicate particles into alkoxides using a simple low temperature chemical process produces a high surface area zeolite particles that are held together via inter-particle oxygen bonding. Addition of water in the resulting zeolite particles produces a sol-gel reaction called "inorganic polymerization" which gives a strong solid material after a curing process at 60 C. The aqueous solution by-product of the reaction is currently being investigated for its reusability; an essential component of any ISRU technology. For this study, two batches of regolith bricks are synthesized from JSC-1A; the first batch from fresh solvents and chemicals, the second batch made from the water solution by-product of the first batch. This is done to determine the feasibility of recycling necessary components of the synthesis process, mainly water. Characterization including BET surface area, SEM, and EDS has been done on the regolith bricks as well as the constituent particles,. The specific surface area of 17.53 sq m/g (average) of the granular regolith

  10. Comparison of Measurements of Internal Temperatures in Ablation Material by Various Thermocouple Configurations

    National Research Council Canada - National Science Library

    Dow, Marvin

    1964-01-01

    .... The measurement of internal temperatures in materials with low values of thermal conductivity subjected to severe heating by thermocouples requires that the thermocouple produce a minimum temperature...

  11. LABORATORY EVALUATION OF THE LOW TEMPERATURE CHARACTERISTICS OF FOUR PROTECTIVE CLOTHING MATERIALS

    Science.gov (United States)

    The objective of the study was to evaluate several low-temperature characteristics of Challenge 5100, a new protective clothing material developed by Chemical Fabrics Corporation. The low temperature characteristics of three other protective clothing materials were also evaluated...

  12. 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...

  13. 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.

  14. Recommended reference materials for realization of physicochemical properties pressure-volume-temperature relationships

    CERN Document Server

    Herington, E F G

    1977-01-01

    Recommended Reference Materials for Realization of Physicochemical Properties presents recommendations of reference materials for use in measurements involving physicochemical properties, namely, vapor pressure; liquid-vapor critical temperature and critical pressure; orthobaric volumes of liquid and vapor; pressure-volume-temperature properties of the unsaturated vapor or gas; and pressure-volume-temperature properties of the compressed liquid. This monograph focuses on reference materials for vapor pressures at temperatures up to 770 K, as well as critical temperatures and critical pressures

  15. Measurements on insulating materials at cryogenic temperatures. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-01-01

    Progress made to date on developing instrumentation and measurement methodology for studying high-voltage dielectric losses at cryogenic temperatures is detailed. The work described has been done in support of ERDA-funded ac superconducting transmission line projects at Brookhaven National Laboratory (BNL) and the Linde Division of the Union Carbide Corporation (UCC-Linde). Dissipation factor measurements have been made at a temperature of 4.2/sup 0/K and at stresses up to 40 kV/mm. Care has been taken to insure that errors in dissipation factor measurements are less than +-1 x 10/sup -6/. Sample dielectrics have included polymer tapes of interest to BNL and epoxy spacer material of interest to UCC-Linde. When dissipation factor measurements are made at high voltage, losses at sample interfaces become important. Flexible superconducting cables are designed to have many layers of coaxially wound plastic tape serving as the insulation. The spaces between tape layers will be impregnated with helium at pressures up to 1.5 MPa. Plans to investigate high-voltage dielectric losses under these conditions are discussed including a technique for measuring partial discharges using pulse-height analysis.

  16. 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.)

  17. 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.

  18. New Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Allan J. Jacobson

    2006-09-30

    Operation of SOFCs at intermediate temperatures (500-800 C) requires new combinations of electrolyte and electrode materials that will provide both rapid ion transport across the electrolyte and electrode-electrolyte interfaces and efficient electrocatalysis of the oxygen reduction and fuel oxidation reactions. This project concentrates on materials and issues associated with cathode performance that are known to become limiting factors as the operating temperature is reduced. The specific objectives of the proposed research are to develop cathode materials that meet the electrode performance targets of 1.0 W/cm{sup 2} at 0.7 V in combination with YSZ at 700 C and with GDC, LSGM or bismuth oxide based electrolytes at 600 C. The performance targets imply an area specific resistance of {approx}0.5 {Omega}cm{sup 2} for the total cell. The research strategy is to investigate both established classes of materials and new candidates as cathodes, to determine fundamental performance parameters such as bulk diffusion, surface reactivity and interfacial transfer, and to couple these parameters to performance in single cell tests. The initial choices for study were perovskite oxides based on substituted LaFeO{sub 3} (P1 compositions), where significant data in single cell tests exist at PNNL for example, for La{sub 0.8}Sr{sub 0.2}FeO{sub 3} cathodes on both YSZ and CSO/YSZ. The materials selection was then extended to La{sub 2}NiO{sub 4} compositions (K1 compositions), and then in a longer range task we evaluated the possibility of completely unexplored group of materials that are also perovskite related, the ABM{sub 2}O{sub 5+{delta}}. A key component of the research strategy was to evaluate for each cathode material composition, the key performance parameters, including ionic and electronic conductivity, surface exchange rates, stability with respect to the specific electrolyte choice, and thermal expansion coefficients. In the initial phase, we did this in parallel with

  19. Model of the magnetization of nanocrystalline materials at low temperatures

    Science.gov (United States)

    Bian, Q.; Niewczas, M.

    2014-07-01

    A theoretical model incorporating the material texture has been developed to simulate the magnetic properties of nanocrystalline materials at low temperatures where the effect of thermal energy on magnetization is neglected. The method is based on Landau-Lifshitz-Gilbert (LLG) theory and it describes the magnetization dynamics of individual grains in the effective field. The modified LLG equation incorporates the intrinsic fields from the intragrain magnetocrystalline and grain boundary anisotropies and the interacting fields from intergrain dipolar and exchange couplings between the neighbouring grains. The model is applied to study magnetic properties of textured nanocrystalline Ni samples at 2K and is capable to reproduce closely the hysteresis loop behaviour at different orientations of applied magnetic field. Nanocrystalline Ni shows the grain boundary anisotropy constant K 1 s = - 6.0 × 104 J / m 3 and the intergrain exchange coupling denoted by the effective exchange constant Ap = 2.16 × 10-11 J/m. Analytical expressions to estimate the intergrain exchange energy density and the effective exchange constant have been formulated.

  20. 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.

  1. Full scale test SSP 34m blade, edgewise loading LTT. Extreme load and PoC{sub I}nvE Data report

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Magda; Roczek-Sieradzan, A.; Jensen, Find M. (and others)

    2010-09-15

    This report is the second report covering the research and demonstration project 'Experimental blade research: Structural mechanisms in current and future large blades under combined loading', supported by the EUDP program. A 34m wind turbine blade from SSP-Technology A/S has been tested in edgewise direction (LTT). The blade has been submitted to thorough examination by means of strain gauges, displacement transducers and a 3D optical measuring system. This data report presents results obtained during full scale testing of the blade up to 80% Risoe load, where 80% Risoe load corresponds to 100% certification load. These pulls at 80% Risoe load were repeated and the results from these pulls were compared. The blade was reinforced according to a Risoe DTU invention, where the trailing edge panels are coupled. The coupling is implemented to prevent the out of plane deformations and to reduce peeling stresses in the adhesive joints. Test results from measurements with the reinforcement have been compared to results without the coupling. The report presents only the relevant results for the 80% Risoe load and the results applicable for the investigation of the influence of the invention on the profile deformation. (Author)

  2. 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

  3. Magnetic antiskyrmions above room temperature in tetragonal Heusler materials

    Science.gov (United States)

    Nayak, Ajaya K.; Kumar, Vivek; Ma, Tianping; Werner, Peter; Pippel, Eckhard; Sahoo, Roshnee; Damay, Franoise; Rößler, Ulrich K.; Felser, Claudia; Parkin, Stuart S. P.

    2017-08-01

    Magnetic skyrmions are topologically stable, vortex-like objects surrounded by chiral boundaries that separate a region of reversed magnetization from the surrounding magnetized material. They are closely related to nanoscopic chiral magnetic domain walls, which could be used as memory and logic elements for conventional and neuromorphic computing applications that go beyond Moore’s law. Of particular interest is ‘racetrack memory’, which is composed of vertical magnetic nanowires, each accommodating of the order of 100 domain walls, and that shows promise as a solid state, non-volatile memory with exceptional capacity and performance. Its performance is derived from the very high speeds (up to one kilometre per second) at which chiral domain walls can be moved with nanosecond current pulses in synthetic antiferromagnet racetracks. Because skyrmions are essentially composed of a pair of chiral domain walls closed in on themselves, but are, in principle, more stable to perturbations than the component domain walls themselves, they are attractive for use in spintronic applications, notably racetrack memory. Stabilization of skyrmions has generally been achieved in systems with broken inversion symmetry, in which the asymmetric Dzyaloshinskii-Moriya interaction modifies the uniform magnetic state to a swirling state. Depending on the crystal symmetry, two distinct types of skyrmions have been observed experimentally, namely, Bloch and Néel skyrmions. Here we present the experimental manifestation of another type of skyrmion—the magnetic antiskyrmion—in acentric tetragonal Heusler compounds with D2d crystal symmetry. Antiskyrmions are characterized by boundary walls that have alternating Bloch and Néel type as one traces around the boundary. A spiral magnetic ground-state, which propagates in the tetragonal basal plane, is transformed into an antiskyrmion lattice state under magnetic fields applied along the tetragonal axis over a wide range of temperatures

  4. 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.

  5. Development of Web Based Learning Material in Physics Subject for Kalor and Temperature Material

    Directory of Open Access Journals (Sweden)

    Fatwa Aji Kurniawan

    2015-12-01

    Full Text Available It has been done, the research which aims to develop a web-based teaching materials on the subjects of physics subject with subject mater of temperature and heat. This study using a modified model of the 4D development by eliminating the deployment phase. The validation of product development conducted by validator media experts and experts matter of physics, whereas small-scale trials conducted by physics teacher and 10 students. Validator review results stating that the quality of the product development were included in the category very well with the average percentage rating of 83.93%. The percentage value assigned by media expert by 75% in the good category and the percentage of the value provided by a matter expert 92.85% were in the very good category. Experiments by physics teacher to obtain result of equal to 94.44% were in the very good category and the average percentage of the test results by the students of 90.5% were in the very good category. The characteristics of the products developed include material composition using the curriculum in 2013, there was a recording facility and the results of evaluation of students' activities, there were feedback evaluation results were immediately known by the students and there were some links related to the material either youtube or other learning website.

  6. Influence of the material for preformed moulds on the polymerization temperature of resin materials for temporary FPDs.

    Science.gov (United States)

    Pott, Philipp-Cornelius; Schmitz-Wätjen, Hans; Stiesch, Meike; Eisenburger, Michael

    2017-08-01

    Temperature increase of 5.5 ℃ can cause damage or necrosis of the pulp. Increasing temperature can be caused not only by mechanical factors, e.g. grinding, but also by exothermic polymerization reactions of resin materials. The aim of this study was to evaluate influences of the form material on the intrapulpal temperature during the polymerization of different self-curing resin materials for temporary restorations. 30 provisonal bridges were made of 5 resin materials: Prevision Temp (Pre), Protemp 4 (Pro), Luxatemp Star (Lux), Structure 3 (Str) and an experimental material (Exp). Moulds made of alginate (A) and of silicone (S) and vacuum formed moulds (V) were used to build 10 bridges each on a special experimental setup. The intrapulpal temperatures of three abutment teeth (a canine, a premolar, and a molar,) were measured during the polymerization every second under isothermal conditions. Comparisons of the maximum temperature (TMax) and the time until the maximum temperature (tTMax) were performed using ANOVA and Tukey Test. Using alginate as the mould material resulted in a cooling effect for every resin material. Using the vacuum formed mould, TMax increased significantly compared to alginate (Pmaterial on tTMax. All of the mould materials are suitable for clinical use if the intraoral application time does not exceed the manufacturer's instructions for the resin materials.

  7. Properties of magnetocaloric materials with a distribution of Curie temperatures

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Bjørk, Rasmus; Smith, Anders

    2012-01-01

    The magnetocaloric properties of inhomogeneous ferromagnets that contain distributions of Curie temperatures are considered as a function of the width of such a distribution. Assuming a normal distribution of the Curie temperature, the average adiabatic temperature change, ΔTad, the isothermal...

  8. 49 CFR 173.224 - Packaging and control and emergency temperatures for self-reactive materials.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Packaging and control and emergency temperatures... temperatures for self-reactive materials. (a) General. When the § 172.101 table of this subchapter specifies... packagings meeting Packing Group I are not authorized. Self-reactive materials which require temperature...

  9. 49 CFR 173.247 - Bulk packaging for certain elevated temperature materials.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bulk packaging for certain elevated temperature... Than Class 1 and Class 7 § 173.247 Bulk packaging for certain elevated temperature materials. When... constructed of carbon steel which is in elevated temperature material service is excepted from § 178.345-7(d...

  10. 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

  11. 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....

  12. 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.

  13. Characterization of energetic materials at temperatures approaching cookoff

    Energy Technology Data Exchange (ETDEWEB)

    Renlund, A.M.; Miller, J.C.; Trott, W.M.; Erickson, K.L.; Hobbs, M.L.

    1997-11-01

    The authors conducted experiments that monitored the response of heated, confined energetic materials in both fixed-volume and fixed-load configurations. They studied a variety of HMX-based materials, looking at the effects of particle size and binders. The {beta}-{delta} phase transition near 170 C led to a more reactive state. Materials that underwent complete transition in the fixed-load experiments (allowed to expand fully to accommodate the 5% volume increase) cooked off faster than those in the fixed-volume configuration.

  14. Efficient Space Hardy Thermoelectric Materials with Broad Temperature Range Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this work is to develop new thermoelectric materials for use in fabricating solid state cooling devices and electrical power generators, which are 200 to...

  15. Efficient Space Hardy Thermoelectric Materials with Broad Temperature Range Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this work is developing new thermoelectric materials for use in fabricating solid state cooling devices and electrical power generators, which are 200 to...

  16. 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.

  17. Pressure and Temperature Sensors Using Two Spin Crossover Materials

    Directory of Open Access Journals (Sweden)

    Catalin-Maricel Jureschi

    2016-02-01

    Full Text Available The possibility of a new design concept for dual spin crossover based sensors for concomitant detection of both temperature and pressure is presented. It is conjectured from numerical results obtained by mean field approximation applied to a Ising-like model that using two different spin crossover compounds containing switching molecules with weak elastic interactions it is possible to simultaneously measure P and T. When the interaction parameters are optimized, the spin transition is gradual and for each spin crossover compounds, both temperature and pressure values being identified from their optical densities. This concept offers great perspectives for smart sensing devices.

  18. The Effect of Elevated Temperature on Concrete Materials and Structures - a Literature Review.

    Energy Technology Data Exchange (ETDEWEB)

    Naus, Dan J [ORNL

    2006-03-01

    The objective of this limited study was to provide an overview of the effects of elevated temperature on the behavior of concrete materials and structures. In meeting this objective the effects of elevated temperatures on the properties of ordinary Portland cement concrete constituent materials and concretes are summarized. The effects of elevated temperature on high-strength concrete materials are noted and their performance compared to normal strength concretes. A review of concrete materials for elevated-temperature service is presented. Nuclear power plant and general civil engineering design codes are described. Design considerations and analytical techniques for evaluating the response of reinforced concrete structures to elevated-temperature conditions are presented. Pertinent studies in which reinforced concrete structural elements were subjected to elevated temperatures are described.

  19. Apparatus and test method for characterizing the temperature regulating properties of thermal functional porous polymeric materials

    Science.gov (United States)

    Yao, Bao-guo; Zhang, Shan; Zhang, De-pin

    2017-05-01

    In order to evaluate the temperature regulating properties of thermal functional porous polymeric materials such as fabrics treated with phase change material microcapsules, a new apparatus was developed. The apparatus and the test method can measure the heat flux, temperature, and displacement signals during the dynamic contact and then quickly give an evaluation for the temperature regulating properties by simulating the dynamic heat transfer and temperature regulating process when the materials contact the body skin. A series of indices including the psychosensory intensity, regulating capability index, and relative regulating index were defined to characterize the temperature regulating properties. The measurement principle, the evaluation criteria and grading method, the experimental setup and the test results discussion, and the gage capability analysis of the apparatus are presented. The new apparatus provides a method for the objective measurement and evaluation of the temperature regulating properties of thermal functional porous polymeric materials.

  20. 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

  1. Temperature and pH sensors based on graphenic materials.

    Science.gov (United States)

    Salvo, P; Calisi, N; Melai, B; Cortigiani, B; Mannini, M; Caneschi, A; Lorenzetti, G; Paoletti, C; Lomonaco, T; Paolicchi, A; Scataglini, I; Dini, V; Romanelli, M; Fuoco, R; Di Francesco, F

    2017-05-15

    Point-of-care applications and patients' real-time monitoring outside a clinical setting would require disposable and durable sensors to provide better therapies and quality of life for patients. This paper describes the fabrication and performances of a temperature and a pH sensor on a biocompatible and wearable board for healthcare applications. The temperature sensor was based on a reduced graphene oxide (rGO) layer that changed its electrical resistivity with the temperature. When tested in a human serum sample between 25 and 43°C, the sensor had a sensitivity of 110±10Ω/°C and an error of 0.4±0.1°C compared with the reference value set in a thermostatic bath. The pH sensor, based on a graphene oxide (GO) sensitive layer, had a sensitivity of 40±4mV/pH in the pH range between 4 and 10. Five sensor prototypes were tested in a human serum sample over one week and the maximum deviation of the average response from reference values obtained by a glass electrode was 0.2pH units. For biological applications, the temperature and pH sensors were successfully tested for in vitro cytotoxicity with human fibroblast cells (MRC-5) over 24h. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Advanced Low Temperature Thermoelectric Materials for Cryogenic Power Generation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this work we will: 1) develop novel TE materials  with a factor of 2x or more improvement in the dimensionless TE figure of merit (ZT) over state-of-the-art...

  9. 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

  10. Thin Film Materials and Devices for Resistive Temperature Sensing Applications

    Science.gov (United States)

    2015-05-21

    is based on the phenomenon known as the Seebeck effect . Named after the T. Seebeck who first observed this effect , he noted that there is a current...this effect is known as the thermal electromotive force. A device which uses the Seebeck effect for the measurement of temperature is known as a...21 Figure 2-7. Graph showing the effect of total deposition pressure on TCR and resistivity of deposited pm-Ge:H thin films

  11. Characterization of temperature-dependent optical material properties of polymer powders

    Energy Technology Data Exchange (ETDEWEB)

    Laumer, Tobias [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); SAOT Erlangen Graduate School in Advanced Optical Technologies, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany); Stichel, Thomas; Bock, Thomas; Amend, Philipp [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany); Schmidt, Michael [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); University of Erlangen-Nürnberg, Institute of Photonic Technologies, 91052 Erlangen (Germany); SAOT Erlangen Graduate School in Advanced Optical Technologies, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany)

    2015-05-22

    In former works, the optical material properties of different polymer powders used for Laser Beam Melting (LBM) at room temperature have been analyzed. With a measurement setup using two integration spheres, it was shown that the optical material properties of polymer powders differ significantly due to multiple reflections within the powder compared to solid bodies of the same material. Additionally, the absorption behavior of the single particles shows an important influence on the overall optical material properties, especially the reflectance of the powder bed. Now the setup is modified to allow measurements at higher temperatures. Because crystalline areas of semi-crystalline thermoplastics are mainly responsible for the absorption of the laser radiation, the influence of the temperature increase on the overall optical material properties is analyzed. As material, conventional polyamide 12 and polypropylene as new polymer powder material, is used. By comparing results at room temperature and at higher temperatures towards the melting point, the temperature-dependent optical material properties and their influence on the beam-matter interaction during the process are discussed. It is shown that the phase transition during melting leads to significant changes of the optical material properties of the analyzed powders.

  12. Temperature Dependence and Magnetic Properties of Injection Molding Tool Materials Used in Induction Heating

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Nielsen, Kaspar Kirstein; Hattel, Jesper Henri

    2015-01-01

    To analyze the heating phase of an induction heated injection molding tool precisely, the temperature-dependent magnetic properties, B–H curves, and the hysteresis loss are necessary for the molding tool materials. Hence, injection molding tool steels, core materials among other materials have...

  13. 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

  14. Temperature Dependence Characterization of Layered Materials via the Magneto-Optical Kerr Effect

    Science.gov (United States)

    Zhang, Haoxiang; Stevens, Christopher; Paul, Jagannath; Karaiskaj, Denis; Miller, Casey

    The Curie temperature of PyCu alloy films can be controlled by Cu content. The additional thickness in layered materials changes the Cure temperature and hence the magnetic coupling between permalloy and Cu layers. The decoupling is investigated by the Magneto-Optical Kerr Effect (MOKE) as a function of temperature around the Curie temperature. The measurements reveal the coupling dynamics between permalloy and Co in novel magnetic heterostructures. This research at USF is supported by the National Science Foundation.

  15. Effect of retro-reflective materials on temperature environment in tents

    Directory of Open Access Journals (Sweden)

    Lili Zhang

    2017-03-01

    Full Text Available Due to the low thermal inertia and poor thermal insulation of ultrathin envelope in tents, its indoor temperature environment is extremely bad and its occupants are tormented. Especially under the high solar radiation, both indoor air temperature and inner surface radiation temperature increase rapidly. And thereby, decreasing radiation heat gain in summer is necessary to refine indoor temperature environment in tents. Retro-reflective materials make it a reasonable choice due to their high reflectivity for solar radiation. To reveal the temperature environment improvement of tents by integrating with retro-reflective materials, a comparative experiment is carried out under the summer climatic conditions of Chengdu city, China. Experimental results show that due to integrating with retro-reflective materials, indoor air peak temperature in the tent can be reduced by more than 7.7 °C, while inner surface radiant temperature can be lowered up to 4.8 °C in the day time. It shows retro-reflective materials could refine indoor temperature environment in tents. Through a comparison of the walls in different orientations, on which retro-reflective materials are covered, the top, east and north walls are found to be better choices, while the north wall is the worst one for retro-reflective materials.

  16. Temperature restrictions for materials used in aerospace industry for the near-Sun orbits

    Science.gov (United States)

    Ancona, Elena; Kezerashvili, Roman Ya.

    2017-11-01

    For near-Sun missions, the spacecraft approaches very close to the Sun and space environmental effects become relevant. Strong restrictions on how much close it can get derive from the maximum temperature that the used materials can stand, in order not to compromise the spacecraft's activity and functionalities. In other words, the minimum perihelion distance of a given mission can be determined based on the materials' temperature restrictions. The temperature of an object in space depends on its optical properties: reflectivity, absorptivity, transmissivity, and emissivity. Usually, it is considered as an approximation that the optical properties of materials are constant. However, emissivity depends on temperature. The consideration of the temperature dependence of emissivity and conductivity of materials used in the aerospace industry leads to the conclusion that the temperature dependence on the heliocentric distance is different from the case of constant optical properties [1]. Particularly, taking into account that emissivity is directly proportional to the temperature, the temperature of an object increases as r-2/5 when the heliocentric distance r decreases. This means that the same temperature will actually be reached at a different distance and, eventually, the spacecraft will be allowed to approach closer to the Sun without compromising its activities. We focused on metals used for aerospace structures (Al, Ti), however our analysis can be extended to all kinds of composite materials, once their optical properties - in particular emissivity - are defined.

  17. Thin film materials and devices for resistive temperature sensing applications

    Science.gov (United States)

    Basantani, Hitesh A.

    Thin films of vanadium oxide (VOx) and hydrogenated amorphous silicon (a-Si:H) are the two dominant material systems used in resistive infrared radiation detectors (microbolometers) for sensing long wave infrared (LWIR) wavelengths in the 8--14 microm range. Typical thin films of VO x (x films of hydrogenated germanium (SiGe:H) have |TCR| between 3%/K to 4%/K. Devices made from either of these materials have resulted in similar device performance with NETD ≈ 25 mK. The performance of the microbolometers is limited by the electronic noise, especially 1/f noise. Therefore, regardless of the choice of bolometer sensing material and read out circuitry, manufacturers are constantly striving to reduce 1/f noise while simultaneously increasing TCR to give better signal to noise ratios in their bolometers and ultimately, better image quality with more thermal information to the end user. In this work, thin films of VOx and hydrogenated germanium (Ge:H), having TCR values > 4 %/K are investigated as potential candidates for higher sensitivity next generation of microbolometers. Thin films of VO x were deposited by Biased Target Ion Beam Deposition (BTIBD) (˜85 nm thick). Electrical characterization of lateral resistor structures showed resistivity ranging from 104 O--cm to 2.1 x 104 O--cm, TCR varying from --4%/K to --5%/K, normalized Hooge parameter (alphaH/n) of 5 x 10 -21 to 5 x 10-18 cm3. Thin films of Ge:H were deposited by plasma enhanced chemical vapor deposition (PECVD) by incorporating an increasing amount of crystal fraction in the growing thin films. Thin films of Ge:H having a mixed phase, amorphous + nanocrystalline, having a |TCR| > 6 %/K were deposited with resistivity Higher TCR materials are desired, however, such materials have higher resistivity and therefore unacceptable large electrical resistance in a lateral resistor configuration. This work looks at an alternate bolometer device design which incorporates higher TCR materials in a vertically

  18. 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

  19. 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.

  20. Materials and Components for Low Temperature Solid Oxide Fuel Cells – an Overview

    Directory of Open Access Journals (Sweden)

    D. Radhika

    2013-06-01

    Full Text Available This article summarizes the recent advancements made in the area of materials and components for low temperature solid oxide fuel cells (LT-SOFCs. LT-SOFC is a new trend in SOFCtechnology since high temperature SOFC puts very high demands on the materials and too expensive to match marketability. The current status of the electrolyte and electrode materials used in SOFCs, their specific features and the need for utilizing them for LT-SOFC are presented precisely in this review article. The section on electrolytes gives an overview of zirconia, lanthanum gallate and ceria based materials. Also, this review article explains the application of different anode, cathode and interconnect materials used for SOFC systems. SOFC can result in better performance with the application of liquid fuels such methanol and ethanol. As a whole, this review article discusses the novel materials suitable for operation of SOFC systems especially for low temperature operation.

  1. Feasibility of using microencapsulated phase change materials as filler for improving low temperature performance of rubber sealing materials.

    Science.gov (United States)

    Tiwari, Avinash; Shubin, Sergey N; Alcock, Ben; Freidin, Alexander B; Thorkildsen, Brede; Echtermeyer, Andreas T

    2017-11-01

    The feasibility of a novel composite rubber sealing material to improve sealing under transient cooling (in a so-called blowdown scenario) is investigated here. A composite of hydrogenated nitrile butadiene rubber (HNBR) filled with Micro Encapsulated Phase Change Materials (MEPCM) is described. The fillers contain phase change materials that release heat during the phase transformation from liquid to solid while cooling. This exotherm locally heats the rubber and may improve the function of the seal during a blowdown event. A representative HNBR-MEPCM composite was made and the critical thermal and mechanical properties were obtained by simulating the temperature distribution during a blowdown event. Simulations predict that the MEPCM composites can delay the temperature decrease in a region of the seal during the transient blowdown. A sensitivity analysis of material properties is also presented which highlights possible avenues of improvement of the MEPCMs for sealing applications.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Advanced Materials for Ultrahigh Temperature Structural Applications Above 2000 deg C

    National Research Council Canada - National Science Library

    Upadhya, K

    1997-01-01

    The primary incentive for developing ultrahigh temperature materials for liquid bi-propellant rocket engines lies in the minimization and/or elimination of fuel-film and regenerative cooling of combustion chambers...

  8. Temperature-dependent electrical properties of graphene inkjet-printed on flexible materials.

    Science.gov (United States)

    Kong, De; Le, Linh T; Li, Yue; Zunino, James L; Lee, Woo

    2012-09-18

    Graphene electrode was fabricated by inkjet printing, as a new means of directly writing and micropatterning the electrode onto flexible polymeric materials. Graphene oxide sheets were dispersed in water and subsequently reduced using an infrared heat lamp at a temperature of ~200 °C in 10 min. Spacing between adjacent ink droplets and the number of printing layers were used to tailor the electrode's electrical sheet resistance as low as 0.3 MΩ/□ and optical transparency as high as 86%. The graphene electrode was found to be stable under mechanical flexing and behave as a negative temperature coefficient (NTC) material, exhibiting rapid electrical resistance decrease with temperature increase. Temperature sensitivity of the graphene electrode was similar to that of conventional NTC materials, but with faster response time by an order of magnitude. This finding suggests the potential use of the inkjet-printed graphene electrode as a writable, very thin, mechanically flexible, and transparent temperature sensor.

  9. 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.

  10. YAG:Yb3+ crystal as a potential material for optical temperature sensors

    Science.gov (United States)

    Demirkhanyan, H. G.; Demirkhanyan, G. G.; Kostanyan, R. B.

    2018-02-01

    The possibilities are discussed of Y3Al5O12:Yb3+ crystal as a material for an optical temperature sensor (OTS) based on the temperature dependences of the more intense spectral emission lines and on the ratio of the absorption coefficients from the ground and first excited Stark sublevels. The operating temperature and average sensitivity for OTSs are determined. It is shown that the former is an effective method for an OTS in a cryogenic temperature range (40–130 K) and the latter in a high temperature range (500–1000 K).

  11. 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.

  12. Low Temperature Mechanical Testing of Carbon-Fiber/Epoxy-Resin Composite Materials

    Science.gov (United States)

    Nettles, Alan T.; Biss, Emily J.

    1996-01-01

    The use of cryogenic fuels (liquid oxygen and liquid hydrogen) in current space transportation vehicles, in combination with the proposed use of composite materials in such applications, requires an understanding of how such materials behave at cryogenic temperatures. In this investigation, tensile intralaminar shear tests were performed at room, dry ice, and liquid nitrogen temperatures to evaluate the effect of temperature on the mechanical response of the IM7/8551-7 carbon-fiber/epoxy-resin system. Quasi-isotropic lay-ups were also tested to represent a more realistic lay-up. It was found that the matrix became both increasingly resistant to microcracking and stiffer with decreasing temperature. A marginal increase in matrix shear strength with decreasing temperature was also observed. Temperature did not appear to affect the integrity of the fiber-matrix bond.

  13. A simple method to measure the complex permittivity of materials at variable temperatures

    Science.gov (United States)

    Yang, Xiaoqing; Yin, Yang; Liu, Zhanwei; Zhang, Di; Wu, Shiyue; Yuan, Jianping; Li, Lixin

    2017-10-01

    Measurement of the complex permittivity (CP) of a material at different temperatures in microwave heating applications is difficult and complicated. In this paper a simple and convenient method is employed to measure the CP of a material over variable temperature. In this method the temperature of a sample is increased experimentally to obtain the formula for the relationship between CP and temperature by a genetic algorithm. We chose agar solution (sample) and a Yangshao reactor (microwave heating system) to validate the reliability and feasibility of this method. The physical parameters (the heat capacity, C p , density, ρ, and thermal conductivity, k) of the sample are set as constants in the process of simulation and inversion. We analyze the influence of the variation of physical parameters with temperature on the accuracy of the inversion results. It is demonstrated that the variation of these physical parameters has little effect on the inversion results in a certain temperature range.

  14. Measurement of water transfer and swelling stress in the buffer material due to temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H. [ITC, Tokai, Ibaraki (Japan); Chijimatsu, M.; Fujita, A.

    1999-03-01

    Coefficients concerning the water transfer in the buffer material was obtained by empirically giving a temperature gradient, and the swelling stress was measured when water was soaked in the sample under the uniform temperature and temperature gradient conditions. The distributions of temperature and water in the buffer material empirically given a temperature gradient were measured to deduce water diffusion constant due to the temperature gradient. The diffusion constant was the order of 10{sup -8} cm{sup 2}/s/degC. As a result of a equitemperature soaking test, it was found that the swelling stress of the part where soaktion was slow was greater than that of the part with fast soaking at a stage of non-uniform water distribution. The water soaking quantity to the sample and swelling stress reached a stationary state after 7000 hours and the water distribution in the whole sample was found saturated. (H. Baba)

  15. RESEARCHES REGARDING USE OF TEXTILE MATERIALS FOR THERMAL INSULATION AT NEGATIVE TEMPERATURES

    Directory of Open Access Journals (Sweden)

    IOSUB Andrei

    2014-05-01

    Full Text Available Using thermal insulation in negative temperature acts to reduce heat flow to the cooled space or to objects that have a temperature below ambient temperature. To achieve economic operation of the space to be cooled insulation thickness and quality is an important factor. In this article we want to compare three products used in thermal insulation at negative temperatures: expanded polystyrene, non-woven and wool coats. The materials will be tested with a mechanical vapor compression refrigerator capable of producing temperatures in the range +4 .. -35 ° C, managed by a programmer Dixel capable of recording values between +40. .. -60 °C. Refrigeration insulation enclosure was made with 100 mm expanded polystyrene. On one side of the enclosure will be a cut of 250 * 250 mm, chosen in a central position where the material will be introduced to be tested. The dimensions of the samples are 250 * 250 * 60 mm. To check the insulation properties of materials it will be used a temperature logger capable of recording with two probes temperatures between +125...-40° C. One of the probes will be inserted inside the refrigerator and the second probe will be positioned to the outside of the test material adhered to an aluminum plate, in order to read a average temperature. The difference in thickness of the insulation shall be filled with non-woven material. Hardening the assembly will be made using a 6 mm thick OSB board. The materials will be tested in an identical ambient temperature and humidity.

  16. 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.

  17. Temperature response of biological materials to pulsed non-ablative CO2 laser irradiation

    NARCIS (Netherlands)

    Brugmans, M. J.; Kemper, J.; Gijsbers, G. H.; van der Meulen, F. W.; van Gemert, M. J.

    1991-01-01

    This paper presents surface temperature responses of various tissue phantoms and in vitro and in vivo biological materials in air to non-ablative pulsed CO2 laser irradiation, measured with a thermocamera. We studied cooling off behavior of the materials after a laser pulse, to come to an

  18. 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.

  19. Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials.

    Science.gov (United States)

    Ramakrishnan, Manjusha; Rajan, Ginu; Semenova, Yuliya; Farrell, Gerald

    2016-01-15

    This paper provides an overview of the different types of fiber optic sensors (FOS) that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements.

  20. Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials

    Science.gov (United States)

    Ramakrishnan, Manjusha; Rajan, Ginu; Semenova, Yuliya; Farrell, Gerald

    2016-01-01

    This paper provides an overview of the different types of fiber optic sensors (FOS) that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements. PMID:26784192

  1. Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials

    Directory of Open Access Journals (Sweden)

    Manjusha Ramakrishnan

    2016-01-01

    Full Text Available This paper provides an overview of the different types of fiber optic sensors (FOS that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end-user requirements.

  2. Pengaruh Variasi Kecepatan Stiring & Temperatur Sintering Terhadap Perubahan Struktur Mikro & Fase Material Sensor Gas Tio2

    Directory of Open Access Journals (Sweden)

    Della Dewi Ratnasari

    2014-03-01

    Full Text Available Penelitian material untuk sensor gas ini menggunakan bahan dasar TiO2 dan zat pelarut H2SO4 pekat 98% . Metode pembentuk sol-gel dilakukan dengan sampel di stiring menggunakan magnetic stirrer selama 2,5 jam, kecepatan 600, 700 dan 800 rpm dengan temperatur 200 º C hingga terbentuk gel. Drying dilakukan selama 1 jam dengan temperatur 350 º C, proses kalsinasi selama 1 jam temperatur 500 ºC. Proses selanjutnya serbuk TiO2 dikompaksi dengan tekanan 200 bar agar terbentuk padatan / pellet. Sintering dilakukan pada temperatur 700 ºC selama 1 jam. Karakterisasi material dilakukan dengan alat uji Scanning Electron microscope (SEM dan X-ray diffraction (XRD untuk menganalisa perubahan struktur mikro & fase material keramik TiO2. Berdasarkan hasil pengujian difraksi sinar–x (XRD, variasi stiring 600 rpm, 700 rpm & 800 rpm telah merubah fase anatase (raw material menjadi unstabil fase orthohombik (TiOSO4. Sintering pada temperatur 700 ͦ C telah menyebabkan unstabil fase TiOSO4 menjadi stabil fase TiO2 anatase. Sintesa sol-gel stiring 700 rpm dan 800 rpm dilanjutkan sintering 700 ͦ C menyebabkan reduksi kation Titanium. Berdasarkan hasil SEM, proses sol-gel dapat mereduksi raw material menjadi 130 nm pada kecepatan stiring 700 rpm temperatur operasi 200 ͦ C selama 150 menit.

  3. Quantification of the effect of hysteresis on the adiabatic temperature change in magnetocaloric materials

    DEFF Research Database (Denmark)

    von Moos, Lars; Bahl, Christian R.H.; Nielsen, Kaspar Kirstein

    2014-01-01

    description of the phase transition at varying magnetic fields and temperatures. Using detailed experimental property data, a Preisach type model is used to describe the thermal hysteresis effects and simulate the material under realistic working conditions. We find that the adiabatic temperature change......We quantify the effect of hysteresis on the performance of the magnetocaloric first order material Gd5Si2Ge2 undergoing an ideal active magnetic regenerator (AMR) cycle. The material is carefully characterized through magnetometry (VSM) and calorimetry (DSC) in order to enable an accurate model...

  4. [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.

  5. Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Brinkman, C.R.

    1981-01-01

    Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X.

  6. Material degradation due to moisture and temperature. Part 1: mathematical model, analysis, and analytical solutions

    Science.gov (United States)

    Xu, C.; Mudunuru, M. K.; Nakshatrala, K. B.

    2016-11-01

    The mechanical response, serviceability, and load-bearing capacity of materials and structural components can be adversely affected due to external stimuli, which include exposure to a corrosive chemical species, high temperatures, temperature fluctuations (i.e., freezing-thawing), cyclic mechanical loading, just to name a few. It is, therefore, of paramount importance in several branches of engineering—ranging from aerospace engineering, civil engineering to biomedical engineering—to have a fundamental understanding of degradation of materials, as the materials in these applications are often subjected to adverse environments. As a result of recent advancements in material science, new materials such as fiber-reinforced polymers and multi-functional materials that exhibit high ductility have been developed and widely used, for example, as infrastructural materials or in medical devices (e.g., stents). The traditional small-strain approaches of modeling these materials will not be adequate. In this paper, we study degradation of materials due to an exposure to chemical species and temperature under large strain and large deformations. In the first part of our research work, we present a consistent mathematical model with firm thermodynamic underpinning. We then obtain semi-analytical solutions of several canonical problems to illustrate the nature of the quasi-static and unsteady behaviors of degrading hyperelastic solids.

  7. New Construction and Catalyst Support Materials for Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey

    Proton exchange membrane (PEM) water electrolysis presents an attractive technology allowing to produce hydrogen for further use as a renewable energy source in the "Hydrogen cycle". Electrolysis of water steam at elevated temperatures has several advantages over the low temperature process....... However, at the same time it involves increased demands to dimensional and chemical stability of components against corrosion environment. Therefore, materials utilized in low temperature PEM electrolyzers cannot be used in systems operating above 100 °C and new candidates should be tested. The materials...... gives an introduction into the subject and Chapter 2 subsequently presents the theoretical background of the topic and describes techniques used to characterize catalysts and construction materials. Chapter 3 presents general principles and overview of materials used for PEM water electrolysis. Chapter...

  8. 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.

  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. 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

  11. Rate- and Temperature-Dependent Material Behavior of a Multilayer Polymer Battery Separator

    Science.gov (United States)

    Avdeev, Ilya; Martinsen, Michael; Francis, Alex

    2014-01-01

    Designing battery packs for safety in automotive applications requires multiscale modeling, as macroscopic deformations due to impact cause the mechanical failure of individual cells on a sub-millimeter level. The separator material plays a critical role in this process, as the thinning or perforating of the separator can lead to thermal runaway and catastrophic failure of an entire battery pack. The electrochemical properties of various polymer separators have been extensively investigated; however, the dependency of mechanical properties of these thin films on various factors, such as high temperature and strain rate, has not been sufficiently characterized. In this study, the macroscopic mechanical properties of a multilayer polymer thin film used as a battery separator are studied experimentally at various temperatures, strain rates, and solvent saturations. Due to the anisotropy of the material, material testing was conducted in two perpendicular directions (machine and transverse directions). Material samples were tested in both dry and saturated conditions at several temperatures, and it was found that temperature and strain rate have a nearly linear effect on the stress experienced by the material. Additionally, saturating the separator material in a common lithium-ion solvent had softened it and had a positive effect on its toughness. The experimental results obtained in this study can be used to develop mathematical constitutive models of the multilayer separator material for subsequent numerical simulations and design.

  12. Effects of elevated temperatures on different restorative materials: An aid to forensic identification processes

    Science.gov (United States)

    Pol, Chetan A.; Ghige, Suvarna K.; Gosavi, Suchitra R.; Hazarey, Vinay K.

    2015-01-01

    Background: Heat-induced alterations to dental and restorative materials can be of great interest to forensic dentistry. Knowing the specific optical behavior of dental materials can be of high importance as recognition of changes induced by high temperatures can lead to the determination of material which was used in a dental restoration, facilitating identification of burned human remains. Aim: To observe the effects of predetermined temperatures (200°C–400°C–600°C–800°C–1000°C) on unrestored teeth and different restorative materials macroscopically and then examine them under a stereomicroscope for the purpose of identification. Materials and Methods: The study was conducted on 375 extracted teeth which were divided into five groups of 75 teeth each as follows: group 1- unrestored teeth, group 2- teeth restored with all-ceramic crowns, Group 3- with class I silver amalgam filling, group 4- with class I composite restoration, and group 5- with class I glass ionomer cement restoration. Results: Unrestored and restored teeth display a series of specific macroscopic & stereomicroscopic structural changes for each range of temperature. Conclusion: Dental tissues and restorative materials undergo a series of changes which correlate well with the various temperatures to which they were exposed. These changes are a consequence of the nature of the materials and their physicochemical characteristics. PMID:26005305

  13. Factors contributing to the temperature beneath plaster or fiberglass cast material

    Directory of Open Access Journals (Sweden)

    Hutchinson Mark R

    2008-02-01

    Full Text Available Abstract Background Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints. Methods The temperature beneath various types (plaster, fiberglass, and fiberglass splints, brands, and thickness of cast material were measured after they were applied over thermometer which was on the surface of a single diameter and thickness PVC tube. A single layer of cotton stockinette with variable layers and types of cast padding were placed prior to application of the cast. Serial temperature measurements were made as the cast matured and reached peak temperature. Time to peak, duration of peak, and peak temperature were noted. Additional tests included varying the dip water temperature and assessing external insulating factors. Ambient temperature, ambient humidity and dip water freshness were controlled. Results Outcomes revealed that material type, cast thickness, and dip water temperature played key roles regarding the temperature beneath the cast. Faster setting plasters achieved peak temperature quicker and at a higher level than slower setting plasters. Thicker fiberglass and plaster casts led to greater peak temperature levels. Likewise increasing dip-water temperature led to elevated temperatures. The thickness and type of cast padding had less of an effect for all materials. With a definition of thermal injury risk of skin injury being greater than 49 degrees Celsius, we found that thick casts of extra fast setting plaster consistently approached dangerous levels (greater than 49 degrees for an extended period. Indeed a cast of extra-fast setting plaster, 20 layers thick, placed on a pillow during maturation maintained temperatures over 50 degrees of

  14. Factors contributing to the temperature beneath plaster or fiberglass cast material.

    Science.gov (United States)

    Hutchinson, Michael J; Hutchinson, Mark R

    2008-02-25

    Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints. The temperature beneath various types (plaster, fiberglass, and fiberglass splints), brands, and thickness of cast material were measured after they were applied over thermometer which was on the surface of a single diameter and thickness PVC tube. A single layer of cotton stockinette with variable layers and types of cast padding were placed prior to application of the cast. Serial temperature measurements were made as the cast matured and reached peak temperature. Time to peak, duration of peak, and peak temperature were noted. Additional tests included varying the dip water temperature and assessing external insulating factors. Ambient temperature, ambient humidity and dip water freshness were controlled. Outcomes revealed that material type, cast thickness, and dip water temperature played key roles regarding the temperature beneath the cast. Faster setting plasters achieved peak temperature quicker and at a higher level than slower setting plasters. Thicker fiberglass and plaster casts led to greater peak temperature levels. Likewise increasing dip-water temperature led to elevated temperatures. The thickness and type of cast padding had less of an effect for all materials. With a definition of thermal injury risk of skin injury being greater than 49 degrees Celsius, we found that thick casts of extra fast setting plaster consistently approached dangerous levels (greater than 49 degrees for an extended period). Indeed a cast of extra-fast setting plaster, 20 layers thick, placed on a pillow during maturation maintained temperatures over 50 degrees of Celsius for over 20 minutes. Clinicians should be

  15. 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

  16. The Influence of Aging Period, Freezing Temperature and Packaging Material on Frozen Beef Chemical Quality

    Directory of Open Access Journals (Sweden)

    Aris Sri Widati

    2012-04-01

    Full Text Available The objective of the study was to evaluate the influences of aging period, freezing temperature and packaging material on the frozen beef chemical quality. The material of the study was 2-3 years old Ongole grade beef of the Longissimus dorsi part,  and was then classified into 3 treat­ments, namely A (aging periode; 0, 12 and 24 hours, B (freezing temperature; -10°C and -20°C and C (packaging material; aluminum foil (Al, polyprophylene (PP, poly­ethylene (PE and without packaging material. The ob­served variables were water content, crude protein, fat, ash content. The data were analyzed by the Completely Randomized Design (CRD in the Factorial (3x2x4 pattern. The results indicated that the aging periode de­creased the water content, and ash content significantly (P<0.05, and decreased the crude protein but increased the fat content insignificantly. The lower freezing temperature prevented the decreases of the water content, and ash content significantly (P<0.05, but prevented the decrease of crude protein, fat content insignificantly. The packaging material could prevent the decreases of water content, ash content sig­nificantly (P<0.05, but prevent the decreases of protein, and fat content insignificantly. A significant interaction (P<0.05 occured between the freezing temperature and packaging material factors on ash content of the frozen beef. The conclusion was the frozen beef without aging has a high of water content, protein, and ash, but has a low fat content.Temperature at -200C and using aluminium foil packaging can prevent decreasing quality of frozen beef. Keywords : Aging period, freezing temperature,  packaging material

  17. The impact of individual materials parameters on color temperature reproducibility among phosphor converted LED sources

    Science.gov (United States)

    Schweitzer, Susanne; Nemitz, Wolfgang; Sommer, Christian; Hartmann, Paul; Fulmek, Paul; Nicolics, Johann; Pachler, Peter; Hoschopf, Hans; Schrank, Franz; Langer, Gregor; Wenzl, Franz P.

    2014-09-01

    For a systematic approach to improve the white light quality of phosphor converted light-emitting diodes (LEDs) for general lighting applications it is imperative to get the individual sources of error for color temperature reproducibility under control. In this regard, it is imperative to understand how compositional, optical and materials properties of the color conversion element (CCE), which typically consists of phosphor particles embedded in a transparent matrix material, affect the constancy of a desired color temperature of a white LED source. In this contribution we use an LED assembly consisting of an LED die mounted on a printed circuit board (PCB) by chip-on-board technology and a CCE with a glob-top configuration as a model system and discuss the impact of potential sources for color temperature deviation among individual devices. Parameters that are investigated include imprecisions in the amount of materials deposition, deviations from the target value for the phosphor concentration in the matrix material, deviations from the target value for the particle sizes of the phosphor material, deviations from the target values for the refractive indexes of phosphor and matrix material as well as deviations from the reflectivity of the substrate surface. From these studies, some general conclusions can be drawn which of these parameters have the largest impact on color deviation and have to be controlled most precisely in a fabrication process in regard of color temperature reproducibility among individual white LED sources.

  18. Effects of elevated temperatures on different restorative materials: An aid to forensic identification processes.

    Science.gov (United States)

    Pol, Chetan A; Ghige, Suvarna K; Gosavi, Suchitra R; Hazarey, Vinay K

    2015-01-01

    Heat-induced alterations to dental and restorative materials can be of great interest to forensic dentistry. Knowing the specific optical behavior of dental materials can be of high importance as recognition of changes induced by high temperatures can lead to the determination of material which was used in a dental restoration, facilitating identification of burned human remains. To observe the effects of predetermined temperatures (200°C-400°C-600°C-800°C-1000°C) on unrestored teeth and different restorative materials macroscopically and then examine them under a stereomicroscope for the purpose of identification. The study was conducted on 375 extracted teeth which were divided into five groups of 75 teeth each as follows: group 1- unrestored teeth, group 2- teeth restored with all-ceramic crowns, Group 3- with class I silver amalgam filling, group 4- with class I composite restoration, and group 5- with class I glass ionomer cement restoration. Unrestored and restored teeth display a series of specific macroscopic & stereomicroscopic structural changes for each range of temperature. Dental tissues and restorative materials undergo a series of changes which correlate well with the various temperatures to which they were exposed. These changes are a consequence of the nature of the materials and their physicochemical characteristics.

  19. 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.

  20. 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

  1. Economic impact of using nonmetallic materials in low to intermediate temperature geothermal well construction

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    Four appendices are included. The first covers applications of low-temperature geothermal energy including industrial processes, agricultural and related processes, district heating and cooling, and miscellaneous. The second discusses hydrogeologic factors affecting the design and construction of low-temperature geothermal wells: water quality, withdrawal rate, water depth, water temperature, basic well designs, and hydrogeologic provinces. In the third appendix, properties of metallic and nonmetallic materials are described, including: specific gravity, mechanical strength properties, resistance to physical and biological attack, thermal properties of nonmetallics, fluid flow characteristics, corrosion resistance, scaling resistance, weathering resistance of nonmetallics, and hydrolysis resistance of nonmetallics. Finally, special considerations in the design and construction of low-temperature geothermal wells using nonmetallics materials are covered. These include; drilling methods, joining methods, methods of casing and screen installation, well cementing, and well development. (MHR)

  2. 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.

  3. Electrical Properties of Materials for Elevated Temperature Resistance Strain Gage Application. Ph.D. Thesis

    Science.gov (United States)

    Lei, Jih-Fen

    1987-01-01

    The objective was to study the electrical resistances of materials that are potentially useful as resistance strain gages at 1000 C. Transition metal carbides and nitrides, boron carbide and silicon carbide were selected for the experimental phase of this research. Due to their low temperature coefficient of resistance and good stability, TiC, ZrC, B sub 4 C and beta-SiC are suggested as good candidates for high temperature resistance strain gage applications.

  4. 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.

  5. SIMULASI PENGARUH FRICTION, SPEED, MATERIAL, DAN TEMPERATURE TERHADAP DAMAGE PADA BLOCK PRE FORMING DENGAN METODE TAGUCHI

    Directory of Open Access Journals (Sweden)

    Dicky Tyagita

    2013-06-01

    Full Text Available Pada proses pembentukan logam damage dapat disebabkan oleh beberapa faktor yaitu beban yang bekerja pada benda kerja, temperatur pemanasan awal, dan temperatur yang disebankan gesekan antara die dan material yang akan di lakukan pre forming. Proses metal forming bisa dilakukan dengan 2 cara yaitu pengerjaan panas (hot working dan pengerjaan dingin (cold working. Pada proses pengerjaan panas dan pengerjaan dingin logam mengalami deformasi plastis dan perubahan bentuk. Pada pengerjaan panas, gaya deformasi yang diperlukan adalah lebih rendah dan perubahan sifat mekanik juga tidak siknifikan. Pada pengerjaan dingin, diperlukan gaya yang lebih besar, akan tetapi kekuatan logam tersebut akan meningkat secara signifikan. Tren penggunaan simulasi semakin meningkat dikarenakan mampu memprediksi dan menggambarkan mekanisme proses serta mendapatkan optimasi proses pre forming. Studi yang dilakukan menggunakan simulasi 3 dimensi (3D untuk memprediksi pengaruh variasi friction, speed, material, dan temperature terhadap damage pada block pre forming. Dari hasil simulasi menunjukkan nilai damage terbesar terlihat pada spesimen nomor 9 dengan nilai damage tertinggi sebesar 0,0302 pada variasi friction sebesar 0,2; speed punch 2 inc/s, material al 2xxx, dan temperature 122 °F. Nilai damage terendah terlihat pada spesimen nomor 6 dengan nilai damage tertinggi sebesar 0,0101 pada variasi friction sebesar 0,12; speed punch 2 inc/s, material al 1xxx, dan temperature 122 °F. Nilai load prediction terbesar terlihat pada grafik 1 dengan nilai 1470 klbf. Nilai load prediction terkecil terlihat pada grafik 6 dengan nilai 155

  6. Ultra-low temperature curable nano-silver conductive adhesive for piezoelectric composite material

    Science.gov (United States)

    Yan, Chao; Liao, Qingwei; Zhou, Xingli; Wang, Likun; Zhong, Chao; Zhang, Di

    2018-01-01

    Limited by the low thermal resistance of composite material, ultra-low temperature curable conductive silver adhesive with curing temperature less than 100 °C needed urgently for the surface conduction treatment of piezoelectric composite material. An ultra-low temperature curable nano-silver conductive adhesive with high adhesion strength for the applications of piezoelectric composite material was investigated. The crystal structure of cured adhesive, SEM/EDS analysis, thermal analysis, adhesive properties and conductive properties of different content of nano-silver filler or micron-silver doping samples were studied. The results show that with 60 wt.% nano-silver filler the ultra-low temperature curable conductive silver adhesive had the relatively good conductivity as volume resistivity of 2.37 × 10-4 Ω cm, and good adhesion strength of 5.13 MPa. Minor micron-doping (below 15 wt.%) could improve conductivity, but would decrease other properties. The ultra-low temperature curable nano-silver conductive adhesive could successfully applied to piezoelectric composite material.

  7. 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...

  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. 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.

  10. 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.

  11. 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...

  12. Al doped graphene: A promising material for hydrogen storage at room temperature

    OpenAIRE

    Ao, Z. M.; Jiang, Q.; Zhang, R. Q.; Tan, T. T.; Li, S.

    2008-01-01

    A promising material for hydrogen storage at room temperature-Al doped graphene was proposed theoretically by using density functional theory calculation. Hydrogen storage capacity of 5.13 wt% was predicted at T = 300 K and P = 0.1 Gpa with adsorption energy Eb = -0.260 eV/H2. This is close to the target of 6 wt% and satisfies the requirement of immobilization hydrogen with Eb of -0.2 ~ -0.4 eV/H2 at ambient temperature and modest pressure for commercial applications specified by U.S. Departm...

  13. Substrate material selection method for multilayer diffractive optics in a wide environmental temperature range.

    Science.gov (United States)

    Piao, Mingxu; Cui, Qingfeng; Zhao, Chunzhu; Zhang, Bo; Mao, Shan; Zhao, Yuanming; Zhao, Lidong

    2017-04-01

    We present a substrate material selection method for multilayer diffractive optical elements (MLDOEs) to obtain high polychromatic integral diffraction efficiency (PIDE) in a wide environmental temperature range. The extended expressions of the surface relief heights for the MLDOEs are deduced with consideration of the influence of the environmental temperature. The PIDE difference Δη¯(λ) and PIDE change factor F are introduced to select a reasonable substrate material combination. A smaller value of Δη¯(λ) or F indicates a smaller decrease of the PIDE in a wide temperature range, and the corresponding substrate material combination is better. According to the deduced relation, double-layer and three-layer DOEs with different combinations are discussed. The results show that IRG26 and zinc sulfide is the best substrate material combination in the infrared waveband for double-layer DOEs, and polycarbonate is more reasonable than polymethyl methacrylate as the middle filling optical material for three-layer DOEs when the two substrate materials are the same.

  14. Investigation on the effects of temperature dependency of material parameters on a thermoelastic loading problem

    Science.gov (United States)

    Kumar, Anil; Mukhopadhyay, Santwana

    2017-08-01

    The present work is concerned with the investigation of thermoelastic interactions inside a spherical shell with temperature-dependent material parameters. We employ the heat conduction model with a single delay term. The problem is studied by considering three different kinds of time-dependent temperature and stress distributions applied at the inner and outer surfaces of the shell. The problem is formulated by considering that the thermal properties vary as linear function of temperature that yield nonlinear governing equations. The problem is solved by applying Kirchhoff transformation along with integral transform technique. The numerical results of the field variables are shown in the different graphs to study the influence of temperature-dependent thermal parameters in various cases. It has been shown that the temperature-dependent effect is more prominent in case of stress distribution as compared to other fields and also the effect is significant in case of thermal shock applied at the two boundary surfaces of the spherical shell.

  15. Research on precise control of 3D print nozzle temperature in PEEK material

    Science.gov (United States)

    Liu, Zhichao; Wang, Gong; Huo, Yu; Zhao, Wei

    2017-10-01

    3D printing technology has shown more and more applicability in medication, designing and other fields for its low cost and high timeliness. PEEK (poly-ether-ether-ketone), as a typical high-performance special engineering plastic, become one of the most excellent materials to be used in 3D printing technology because of its excellent mechanical property, good lubricity, chemical resistance, and other properties. But the nozzle of 3D printer for PEEK has also a series of very high requirements. In this paper, we mainly use the nozzle temperature control as the research object, combining with the advantages and disadvantages of PID control and fuzzy control. Finally realize a kind of fuzzy PID controller to solve the problem of the inertia of the temperature system and the seriousness of the temperature control hysteresis in the temperature control of the nozzle, and to meet the requirements of the accuracy of the nozzle temperature control and rapid reaction.

  16. Measurement of water vapour transport through a porous non-hygroscopic material in a temperature gradient

    DEFF Research Database (Denmark)

    Hansen, Thor; Padfield, Tim; Hansen, Kurt Kielsgaard

    2014-01-01

    This was an experiment to identify the driving potential for water vapour diffusion through porous materials in a temperature gradient. The specimen of mineral fibre insulation was placed between a space with controlled temperature and relative humidity and a space with a controlled, higher...... temperature, and a measured but not controlled relative humidity (RH). This assembly was allowed to reach equilibrium with no vapour movement between the spaces, as tested by a constant RH on each side and by zero flux of water vapour measured in the cold side chamber. The RH and temperature values were...... be tested experimentally in this way, but it is reasonable to assume that concentration is the driving potential. The close equality of the concentrations makes it unnecessary to invoke temperature difference as a third possible potential for driving diffusion....

  17. Hot Plate Method with Two Simultaneous Temperature Measurements for Thermal Characterization of Building Materials

    Science.gov (United States)

    Osséni, Sibiath O. G.; Ahouannou, Clément; Sanya, Emile A.; Jannot, Yves

    2017-07-01

    This paper presents a study of the hot plate method with two simultaneous temperature measurements, on the heated and unheated faces of a sample to characterize. The thermal properties of polyvinyl chloride, plaster and laterite were considered to be a representative range of building materials. A 1D quadrupolar model was developed to represent the temperature evolution on the two faces over time. Three-dimensional numerical modeling of a quarter of the testing device with COMSOL software allowed defining the domain of the 1D hypothesis validity. The analysis of estimation possibilities of materials' thermal characteristics, with the developed method, revealed that thermal effusivity can be accurately estimated by using the temperature of the heated face at the beginning of heating. We showed that the simultaneous use of two temperatures enables the estimation of the thermal conductivity with a greater accuracy and over a shorter time interval than using the temperature of the heated face alone. We also demonstrated that under certain conditions (samples with a high ratio of thickness to width) the method with two temperature measurements enabled the estimation of the thermal effusivity and conductivity, while the method with one temperature allowed only the thermal effusivity to be estimated, because of 3D effects. This conclusion was confirmed by experimental results obtained with a mortar sample.

  18. Temperature dependence of optical properties in Nd/Cr:YAG materials

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Yoshiyuki, E-mail: honda-y@ile.osaka-u.ac.jp [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Motokoshi, Shinji [Institute for Laser Technology, 1-8-4 Utsubo-honmachi, Nishi-ku, Osaka 550-0004 (Japan); Jitsuno, Takahisa; Miyanaga, Noriaki; Fujioka, Kana [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Nakatsuka, Masahiro [Institute for Laser Technology, 1-8-4 Utsubo-honmachi, Nishi-ku, Osaka 550-0004 (Japan); Yoshida, Minoru [Kinki University, 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8052 (Japan)

    2014-04-15

    The energy transfer from Cr{sup 3+} to Nd{sup 3+} for Nd/Cr:YAG (Nd: 1.0%, Cr: 2.0%) materials was investigated by measuring the temperature dependences of fluorescence characteristics. The fluorescence intensity of Nd{sup 3+} increased with temperature owing to enhancement of the absorption coefficient of Cr{sup 3+}. The energy transfer efficiency was constant from 77 to 450 K. The energy transfer time decreased with increasing temperature. -- Highlights: • We investigate the energy transfer from Cr{sup 3+} to Nd{sup 3+} in Nd/Cr:YAG materials by measuring the temperature dependence of fluorescence characteristics. • The fluorescence intensity of Nd{sup 3+} increased with temperature owing to enhancement of the absorption coefficient of Cr{sup 3+}. • The energy transfer efficiency was constant from 77 to 450 K. • The energy transfer time decreased with increasing temperature. • Nd/Cr:YAG ceramics pumped by a flash lamp would not only provide high conversion efficiency, but can also be expected to function as an effective laser operating at high temperature.

  19. 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 ...

  20. Effect of Oxygen Concentration on Autogenous Ignition Temperature and Pneumatic Impact Ignitability of Nonmetallic Materials

    Science.gov (United States)

    Smith, Sarah

    2009-01-01

    Extensive test data exist on the ignitability of nonmetallic materials in pure oxygen, but these characteristics are not as well understood for lesser oxygen concentrations. In this study, autogenous ignition temperature testing and pneumatic impact testing were used to better understand the effects of oxygen concentration on ignition of nonmetallic materials. Tests were performed using oxygen concentrations of 21, 34, 45, and 100 %. The following materials were tested: PTFE Teflon(Registered Trademark), Buna-N, Silicone, Zytel(Registered Trademark) 42, Viton(registered Trademark) A, and Vespel(Registered Trademark) SP-21.

  1. 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...

  2. 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.

  3. 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.

  4. Stability of Porcine Epidemic Diarrhea Virus on Fomite Materials at Different Temperatures.

    Science.gov (United States)

    Kim, Yonghyan; Krishna, Venkatramana D; Torremorell, Montserrat; Goyal, Sagar M; Cheeran, Maxim C-J

    2018-02-13

    Indirect transmission of porcine epidemic diarrhea virus (PEDV) ensues when susceptible animals contact PEDV-contaminated fomite materials. Although the survival of PEDV under various pHs and temperatures has been studied, virus stability on different fomite surfaces under varying temperature conditions has not been explored. Hence, we evaluated the survival of PEDV on inanimate objects routinely used on swine farms such as styrofoam, rubber, plastic, coveralls, and other equipment. The titer of infectious PEDV at 4 °C decreased by only 1 to 2 log during the first 5 days, and the virus was recoverable for up to 15 days on Styrofoam, aluminum, Tyvek ® coverall, cloth, and plastic. However, viral titers decreased precipitously when stored at room temperature; no virus was detectable after one day on all materials tested. A more sensitive immunoplaque assay was able to detect virus from Styrofoam, metal, and plastic at 20 days post application, representing a 3-log loss of input virus on fomite materials. Recovery of infectious PEDV from Tyvek ® coverall and rubber was above detection limit at 20 days. Our findings indicate that the type of fomite material and temperatures impact PEDV stability, which is important in understanding the nuances of indirect transmission and epidemiology of PEDV.

  5. Stability of Porcine Epidemic Diarrhea Virus on Fomite Materials at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Yonghyan Kim

    2018-02-01

    Full Text Available Indirect transmission of porcine epidemic diarrhea virus (PEDV ensues when susceptible animals contact PEDV-contaminated fomite materials. Although the survival of PEDV under various pHs and temperatures has been studied, virus stability on different fomite surfaces under varying temperature conditions has not been explored. Hence, we evaluated the survival of PEDV on inanimate objects routinely used on swine farms such as styrofoam, rubber, plastic, coveralls, and other equipment. The titer of infectious PEDV at 4 °C decreased by only 1 to 2 log during the first 5 days, and the virus was recoverable for up to 15 days on Styrofoam, aluminum, Tyvek® coverall, cloth, and plastic. However, viral titers decreased precipitously when stored at room temperature; no virus was detectable after one day on all materials tested. A more sensitive immunoplaque assay was able to detect virus from Styrofoam, metal, and plastic at 20 days post application, representing a 3-log loss of input virus on fomite materials. Recovery of infectious PEDV from Tyvek® coverall and rubber was above detection limit at 20 days. Our findings indicate that the type of fomite material and temperatures impact PEDV stability, which is important in understanding the nuances of indirect transmission and epidemiology of PEDV.

  6. Microscale Polymer Bottles Corked with a Phase-Change Material for Temperature-Controlled Release

    OpenAIRE

    Hyun, Dong Choon; Lu, Ping; Choi, Sang Il; Jeong, Unyong; Xia, Younan

    2013-01-01

    Keep your wine chilled! Microscale polymer bottles are loaded with dye molecules and then corked with a phase-change material (PCM). When temperature is raised beyond its melting point, the PCM quickly melt and trigger an instant release of the encapsulated dye. The release profiles can be manipulated by using a binary mixture of PCMs with different melting points.

  7. Economic impact of using nonmetallic materials in low to intermediate temperature geothermal well construction. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    The results are presented of an exhaustive literature search and evaluation concerning the properties and economics of commercially available nonmetallic well casing and screens. These materials were studied in terms of their use in low to intermediate temperature geothermal well construction.

  8. 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.

  9. 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.

  10. Analysis of polarization offsets observed for temperature-graded ferroelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hui, E-mail: chenhui@syuct.edu.cn; Cheng, Taimin; Zheng, Hanlei; Zhang, Xinxin

    2016-04-08

    A transverse Ising model in the framework of the mean field approximation is developed to analyze the polarization offsets phenomena in temperature-graded ferroelectric materials. A function of two-spin exchange interaction strength has been introduced to describe the ferroelectric distortion due to the distribution of temperature gradients in materials. Comparisons of the computational results with the experimental data reveal some fundamental factors in the formation of polarization offsets. It is shown that ferroelectric distortion has influenced much on polarization offsets in temperature-graded ferroelectric materials. When quantum fluctuation effect as well as ferroelectric distortion is considered, we have successfully reproduced the experimental observations qualitatively, especially for the indistinguishable polarization offsets from the background at small temperature gradients, which were not successfully reproduced in prior theoretical studies. - Highlights: • A transverse Ising model is developed to analyze the polarization offsets phenomena in temperature-graded ferroelectrics. • A function of two-spin exchange interaction strength has been introduced to describe the ferroelectric distortion. • The experimental observations have been successfully reproduced qualitatively. • Ferroelectric distortion and quantum fluctuation effect are the two important factors to influence the polarization offsets.

  11. 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.

  12. 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.

  13. 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.

  14. A finite element technique for non-deterministic thermal deformation analyses including temperature dependent material properties

    Science.gov (United States)

    Case, W. R., Jr.; Walston, W. H., Jr.

    1977-01-01

    A technique utilizing the finite element displacement method is developed for the static analysis of structures subjected to non-deterministic thermal loading in which the material properties, assumed isotropic, are temperature dependent. Matrix equations are developed for the first two statistical moments of the displacements using a third order series expansion for the displacements in terms of the random temperatures. Sample problems are included to demonstrate the range of applicability of the third order series solutions. These solutions are compared with results from Monte Carlo analyses and also, for some problems, with solutions obtained by numerically integrating equations for the statistical properties of the displacements. In general, it is shown that the effect of temperature dependent material properties can have a significant effect on the covariances of the displacements.

  15. Estimation of Temperature Conductivity Coefficient Impact upon Fatigue Damage of Material

    Science.gov (United States)

    Bibik, V.; Galeeva, A.

    2015-09-01

    In the paper we consider the peculiarities of adhesive wear of cutting tools. Simulation of heat flows in the cutting zone showed that, as thermal conduction and heat conductivity of tool material grow, the heat flows from the front and back surfaces to tool holder will increase and so, the temperature of the contact areas of the tool will lower. When estimating the adhesive wear rate of cemented-carbide tool under the cutting rates corresponding to the cutting temperature of up to 900 °C, it is necessary to take the fatigue character of adhesive wear into consideration. The process of accumulation and development of fatigue damage is associated with micro- and macroplastic flowing of material, which is determined by the processes of initiation, motion, generation, and elimination of line defects - dislocations. Density of dislocations grows with increase of the loading cycles amount and increase of load amplitude. Growth of dislocations density leads to loosening of material, formation of micro- and macrocracks. The heat capacity of material grows as the loosening continues. In the given paper the authors prove theoretically that temperature conductivity coefficient which is associated with heat capacity of material, decreases as fatigue wear grows.

  16. Room-temperature Electrochemical Synthesis of Carbide-derived Carbons and Related Materials

    Energy Technology Data Exchange (ETDEWEB)

    Gogotsi, Yury [Drexel Univ., Philadelphia, PA (United States). Nanomaterials Group. Materials Science and Engineering Dept.

    2015-02-28

    This project addresses room-temperature electrochemical etching as an energy-efficient route to synthesis of 3D nanoporous carbon networks and layered 2D carbons and related structures, as well as provides fundamental understanding of structure and properties of materials produced by this method. Carbide-derived-carbons (CDCs) are a growing class of nanostructured carbon materials with properties that are desirable for many applications, such as electrical energy and gas storage. The structure of these functional materials is tunable by the choice of the starting carbide precursor, synthesis method, and process parameters. Moving from high-temperature synthesis of CDCs through vacuum decomposition above 1400°C and chlorination above 400°C, our studies under the previous DOE BES support led to identification of precursor materials and processing conditions for CDC synthesis at temperatures as low as 200°C, resulting in amorphous and highly reactive porous carbons. We also investigated synthesis of monolithic CDC films from carbide films at 250-1200°C. The results of our early studies provided new insights into CDC formation, led to development of materials for capacitive energy storage, and enabled fundamental understanding of the electrolyte ions confinement in nanoporous carbons.

  17. 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.

  18. Super-strong materials for temperatures exceeding 2000 °C

    Science.gov (United States)

    Silvestroni, Laura; Kleebe, Hans-Joachim; Fahrenholtz, William G.; Watts, Jeremy

    2017-01-01

    Ceramics based on group IV-V transition metal borides and carbides possess melting points above 3000 °C, are ablation resistant and are, therefore, candidates for the design of components of next generation space vehicles, rocket nozzle inserts, and nose cones or leading edges for hypersonic aerospace vehicles. As such, they will have to bear high thermo-mechanical loads, which makes strength at high temperature of great importance. While testing of these materials above 2000 °C is necessary to prove their capabilities at anticipated operating temperatures, literature reports are quite limited. Reported strength values for zirconium diboride (ZrB2) ceramics can exceed 1 GPa at room temperature, but these values rapidly decrease, with all previously reported strengths being less than 340 MPa at 1500 °C or above. Here, we show how the strength of ZrB2 ceramics can be increased to more than 800 MPa at temperatures in the range of 1500-2100 °C. These exceptional strengths are due to a core-shell microstructure, which leads to in-situ toughening and sub-grain refinement at elevated temperatures. Our findings promise to open a new avenue to designing materials that are super-strong at ultra-high temperatures.

  19. 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.

  20. Materials insights into low-temperature performances of lithium-ion batteries

    Science.gov (United States)

    Zhu, Gaolong; Wen, Kechun; Lv, Weiqiang; Zhou, Xingzhi; Liang, Yachun; Yang, Fei; Chen, Zhilin; Zou, Minda; Li, Jinchao; Zhang, Yuqian; He, Weidong

    2015-12-01

    Lithium-ion batteries (LIBs) have been employed in many fields including cell phones, laptop computers, electric vehicles (EVs) and stationary energy storage wells due to their high energy density and pronounced recharge ability. However, energy and power capabilities of LIBs decrease sharply at low operation temperatures. In particular, the charge process becomes extremely sluggish at temperatures below -20 °C, which severely limits the applications of LIBs in some cold areas during winter. Extensive research has shown that the electrolyte/electrode composition and microstructure are of fundamental importance to low-temperature performances of LIBs. In this report, we review the recent findings in the role of electrolytes, anodes, and cathodes in the low temperature performances of LIBs. Our overview aims to understand comprehensively the fundamental origin of low-temperature performances of LIBs from a materials perspective and facilitates the development of high-performance lithium-ion battery materials that are operational at a large range of working temperatures.

  1. Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials.

    Science.gov (United States)

    Hagmann, Joseph A; Le, Son T; Richter, Curt A; Seiler, David G

    2016-01-21

    Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

  2. Low-temperature alcoholic fermentation by delignified cellulosic material supported cells of kefir yeast.

    Science.gov (United States)

    Athanasiadis, I; Boskou, D; Kanellaki, M; Koutinas, A A

    1999-10-01

    A novel system for low-temperature alcoholic fermentation of glucose is described. This system consists of kefir yeast immobilized on delignified cellulosic materials. Batch fermentations were carried out at various pH values, and the effect of temperature on kinetic parameters, in the range of 5-30 degrees C, was examined. At pH 4.7 the shortest fermentation time was obtained. The formation of volatiles indicates that the concentration of amyl alcohols (total content of 2-methylbutanol-1 and 3-methylbutanol-1) is reduced as the temperature becomes lower. Propanol-1 and isobutyl alcohol formation drops significantly below 15 degrees C. The percentage of ethyl acetate increases as the temperature is diminished. At 5 degrees C the content of total volatiles in the product was only 38% of the volatiles formed during fermentation at 30 degrees C.

  3. Studies of low temperature, low flux radiation embrittlement of nuclear reactor structural materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G.R.; Lucas, G.E.

    1993-06-01

    There are several existing research programs which have components pertinent to the issue of low flux/low temperature embrittlement; in particular, examination of the Shippingport shield tank which has been exposed to low flux and relatively low temperature is being performed by ANL, and evaluation of low temperature embrittlement in A508 and A533B steels in support of the HTGR is currently being performed by ORNL. However, these programs are not specifically directed at the broader issue of low flux/low temperature embrittlement in a range of structural steels. Hence, the authors coordinated their effort with these programs so that their investigations were complementary to existing programs, and they focused on a set of materials which expand the data base developed in these programs. In particular, the authors have investigated embrittlement phenomena in steels that are similar to those used in support structure.

  4. Furnace for testing materials in air at temperatures up to 1850 deg C

    Science.gov (United States)

    Sotnikov, V. Y.; Smirnitskiy, A. M.; Satanovskiy, A. V.; Balkevich, V. L.; Mosin, Y. M.

    1986-02-01

    A tubular high-temperature air furnace with a La2(CrO3)3 heater element was developed for testing materials. The electrical resistance of this heater element is 200 ohm at 20 C room temperature and 20 to 30 ohms at the top temperature. The helical heater is surrounded by three cylindrical layers of refractory thermally insulating materials within a cylindrical metal enclusure: a layer of high-density corundum on the inside and a layer of ShLB-0.4 fireclay on the outside with a layer of KL-1.3 plain corundum in between. The heater is energized from a 220 V - 50Hz power line through a thyristor bank. The furnace temperature is controlled by a high-precision regulator around the heater extension above the lining, with a PR(Pt-Rh) 30/6 thermocouple mounted preferably inside rather than outside the heater coil for faster response and better accuracy. The test tube with a specimen is inserted inside the heater coil, where it can remain for more than 50 h at 1850 C and for short periods at 1900 C. The furnace can be cycled at least 50 times in a row by heating at a rate of 20 C/min and then cooling to 20 C. Refractory materials can be tested in this furnace also with air replaced by an oxidizing atmosphere.

  5. 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.

  6. 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.

  7. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material

    Science.gov (United States)

    Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

    2017-03-01

    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 hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials.

  8. Temperature dependence of the elastic constant of Borassus Flabellifier 'BF' material by acoustic response

    Science.gov (United States)

    Phadke, Sushil; Dshrivastava, B.; Dagaonkar, N.; Mishra, Ashutosh

    2012-05-01

    The homogeneous continuous materials are widely used for many structural applications. Migrations of atoms or molecules are the mechanism of mechanical and kinetic processes in materials for their synthesis processing as well as for their structural evolutions. The elastic constant of solids provides valuable information on their mechanical and dynamical properties. In particular, they provide information on the stability and stiffness of materials. In the present study author investigated relation between elastic constant and temperature in Borassus Flabellifier 'BF' wood part. Determination of elastic properties of material is based on the longitudinal wave's velocities via ultrasonic methods. The resonant frequencies of the specimens were measured by Ultrasonic Interferometer (for solids) dual frequency using longitudinal cubic piezoelectric crystal of quartz of frequency 123.62 KHz. The temperature variations from room temperature were done by PID control unit, Mittal Enterprises, New Delhi, India. Characterization of the samples was done by scanning electron microscope (SEM) Model JEOL JSM5400 at 5.0kvx750, 10 μm.

  9. Manganese mono-boride, an inexpensive room temperature ferromagnetic hard material.

    Science.gov (United States)

    Ma, Shuailing; Bao, Kuo; Tao, Qiang; Zhu, Pinwen; Ma, Teng; Liu, Bo; Liu, Yazhou; Cui, Tian

    2017-03-06

    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 hardness (AVH) is 15.7 GPa which is far higher than that of traditional ferromagnetic materials. The high hardness is ascribed to the zigzag boron chains running through manganese lattice, as unraveled by X-ray photoelectron spectroscopy result and first principle calculations. This exploration opens a new class of materials with the integration of superior mechanical properties, lower cost, electrical conductivity, and fantastic soft magnetic properties which will be significant for scientific research and industrial application as advanced structural and functional materials.

  10. 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.

  11. Lauric and myristic acids eutectic mixture as phase change material for low-temperature heating applications

    Energy Technology Data Exchange (ETDEWEB)

    Keles, Sadat; Kaygusuz, Kamil [Karadeniz Technical Univ., Dept. of Chemistry, Trabzon (Turkey); Sari, Ahmet [Gaziosmanpasa Univ., Dept. of Chemistry, Tokat (Turkey)

    2005-07-01

    Lauric acid (m.p.: 42.6 deg C) and myristic acid (m.p.: 52.2 deg C) are phase change materials (PCM) having quite high melting points which can limit their use in low-temperature solar applications such as solar space heating and greenhouse heating. However, their melting temperatures can be tailored to appropriate value by preparing a eutectic mixture of lauric acid (LA) and myristic acid (MA). In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of 66.0 wt% LA forms a eutectic mixture having melting temperature of 34.2 deg C and the latent heat of fusion of 166.8 J g{sup -1} . This study also considers the experimental establishment of thermal characteristics of the eutectic PCM in a vertical concentric pipe-in-pipe heat storage system. Thermal performance of the PCM was evaluated with respect to the effect of inlet temperature and mass flow rate of the heat transfer fluid on those characteristics during the heat charging and discharging processes. The DSC thermal analysis and the experimental results indicate that the LA-MA eutectic PCM can be potential material for low-temperature solar energy storage applications in terms of its thermo-physical and thermal characteristics. (Author)

  12. Synthesis of hydrogen-carbon clathrate material and hydrogen evolution therefrom at moderate temperatures and pressures

    Science.gov (United States)

    Lueking, Angela [State College, PA; Narayanan, Deepa [Redmond, WA

    2011-03-08

    A process for making a hydrogenated carbon material is provided which includes forming a mixture of a carbon source, particularly a carbonaceous material, and a hydrogen source. The mixture is reacted under reaction conditions such that hydrogen is generated and/or released from the hydrogen source, an amorphous diamond-like carbon is formed, and at least a portion of the generated and/or released hydrogen associates with the amorphous diamond-like carbon, thereby forming a hydrogenated carbon material. A hydrogenated carbon material including a hydrogen carbon clathrate is characterized by evolution of molecular hydrogen at room temperature at atmospheric pressure in particular embodiments of methods and compositions according to the present invention.

  13. 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...

  14. Porous Carbon Materials for Elements in Low-Temperature Fuel Cells

    Directory of Open Access Journals (Sweden)

    Wlodarczyk R.

    2015-04-01

    Full Text Available The porosity, distribution of pores, shape of pores and specific surface area of carbon materials were investigated. The study of sintered graphite and commercial carbon materials used in low-temperature fuel cells (Graphite Grade FU, Toray Teflon Treated was compared. The study covered measurements of density, microstructural examinations and wettability (contact angle of carbon materials. The main criterion adopted for choosing a particular material for components of fuel cells is their corrosion resistance under operating conditions of hydrogen fuel cells. In order to determine resistance to corrosion in the environment of operation of fuel cells, potentiokinetic curves were registered for synthetic solution 0.1M H2SO4+ 2 ppmF-at 80°C.

  15. Full-Vector, Low-Temperature Magnetic Measurements of Geologic Materials

    Science.gov (United States)

    Feinberg, J.; Sølheid, P.; Bowles, J. A.; Jackson, M. J.; Moskowitz, B. M.

    2010-12-01

    The magnetic properties of geologic materials offer insights into an enormous range of important geophysical phenomena ranging from core dynamics to paleoclimate. Low-temperature (pulse magnetizers. Used in conjunction with the in-line degausser on the IRM’s pass-through magnetometer, it will ultimately be possible to acquire anhysteretic remanence (ARM) and/or AF demagnetize samples at cryogenic temperatures. The intent of this presentation is to advertise the capabilities of the cryogenic insert and to encourage members of the rock magnetic community to plan on using the instrument to further their own research.

  16. 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.

  17. Temperature rise on dentin caused by temporary crown and fixed partial denture materials: influencing factors.

    Science.gov (United States)

    Seelbach, Paul; Finger, Werner J; Ferger, Paul; Balkenhol, Markus

    2010-12-01

    Temporary crowns and fixed partial denture materials (t-c&b) generate exothermic heat during polymerization. The amount of temperature, reaching the pulp chamber, is dependent on the residual thickness of the prepared dentin as well as the volume of the t-c&b used. Hence, the aim of this study was to investigate the influence of both factors on the temperature rise at the pulpal dentin surface as well as in the bulk of the t-c&b during polymerization. Four t-c&bs (Luxatemp AM Plus, Protemp 3 Garant, Structur Premium, Trim) were used to fabricate flat cylindrical specimens (∅ 15.5mm) of different thicknesses (1, 2 and 4mm) using an over-impression placed on top of dentin discs (thickness 0.5, 1 and 2mm). Temperature was recorded at the pulpal dentin surface as well as inside the t-c&b (n=6). Data was subjected to parametric statistics (α=0.05). Peak temperatures inside the t-c&b varied between 37.0°C and 51.9°C and at the pulpal dentin side between 37.0°C and 50.6°C. The maximum temperatures registered depended significantly on the thickness of the dentin disc and t-c&b, respectively (ANOVA ptemperatures were reached 2-3 min after start of mixing (dimethacrylates) and 6 min (mono-methacrylate), respectively, whereas Trim exhibited significantly higher peak temperatures (ptemperature rise may become critical if the material is not cooled properly. Composite-based t-c&bs showed significant lower curing temperatures than Trim and should therefore be preferred in daily practice. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Effect of Different Denture Base Materials and Changed Mouth Temperature on Dimensional Stability of Complete Dentures

    Directory of Open Access Journals (Sweden)

    Khalid A. O. Arafa

    2016-01-01

    Full Text Available Background. Type of materials used in fabrication of denture base has an effect on dimension during denture base material processing and other factors related to clinical use. Objective. The study aims were to assess the dimensional stability including thermal changes of three different denture base materials. Methods. Ninety patients were selected to construct complete dentures with different denture base materials. They were randomly divided into three groups: group 1, patients with cobalt chrome metallic base; group 2, patients with heat curing acrylic resin fabricated by injection moulding technique; and group 3, patients with denture bases fabricated by conventional heat curing acrylic resin. The dimensional changes were assessed using digital caliper. Results. After the twelfth month, injection moulding acrylic resin had significantly the highest dimensional change followed by the conventional heat curing acrylic resin. There were no significant differences in the dimensions between the three types of denture base materials at normal mouth temperature, while, after hot tea drinking at 45°C, the dimensional change was significantly the highest in cobalt chrome metallic denture base group. Conclusion. Cobalt chrome metallic denture base has stable dimension compared to denture bases fabricated of acrylic resin but it was more affected by altered mouth temperature. The study was registered in the International Standard Randomized Controlled Trials Number (ISRCTN registry with study ID (ISRCTN94238244.

  19. 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.

  20. 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.

  1. 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.

  2. Temperature Prediction in a Free-Burning Arc and Electrodes for Nanostructured Materials and Systems.

    Science.gov (United States)

    Lee, Won-Ho; Kim, Youn-Jea; Lee, Jong-Chul

    2015-11-01

    Temperature in a free-burning arc used for synthesis of nanoparticles and nanostructured materials is generally around 20,000 K just below the cathode, falling to about 15,000 K just above the anode, and decreasing rapidly in the radial direction. Therefore, the electrode erosion is indispensable for these atmospheric plasma systems, as well as for switching devices, due to the high heat flux transferred from high temperature arcs to electrodes, but experimental and theoretical works have not identified the characteristic phenomena because of the complex physical processes. To the previous study, we have focused on the arc self-induced fluid flow in a free-burning arc using the computational fluid dynamics (CFD) technique. At this time, our investigation is concerned with the whole region of free-burning high-intensity arcs including the tungsten cathode, the arc plasma and the anode using a unified numerical model for applying synthesis of nanoparticles and nanostructured materials practically.

  3. An additive approach to low temperature zero pressure sintering of bismuth antimony telluride thermoelectric materials

    Science.gov (United States)

    Catlin, Glenn C.; Tripathi, Rajesh; Nunes, Geoffrey; Lynch, Philip B.; Jones, Howard D.; Schmitt, Devin C.

    2017-03-01

    This paper presents an additive-based approach to the formulation of thermoelectric materials suitable for screen printing. Such printing processes are a likely route to such thermoelectric applications as micro-generators for wireless sensor networks and medical devices, but require the development of materials that can be sintered at ambient pressure and low temperatures. Using a rapid screening process, we identify the eutectic combination of antimony and tellurium as an additive for bismuth-antimony-telluride that enables good thermoelectric performance without a high pressure step. An optimized composite of 15 weight percent Sb7.5Te92.5 in Bi0.5Sb1.5Te3 is scaled up and formulated into a screen-printable paste. Samples fabricated from this paste achieve a thermoelectric figure of merit (ZT) of 0.74 using a maximum processing temperature of 748 K and a total thermal processing budget of 12 K-hours.

  4. Time resolved quantitative imaging of charring in materials at temperatures above 1000 K

    Science.gov (United States)

    Böhrk, Hannah; Jemmali, Raouf

    2016-07-01

    A device is presented allowing for in situ investigation of chemically changing materials by means of X-ray imaging. A representative cork ablator sample, additionally instrumented with thermocouples, is encapsulated in an evacuated cell heating a sample surface with a heat flux of 230 kW/m2. The images show the sample surface and the in-depth progression of the char front dividing the char layer from the virgin material. Correlating the images to thermocouple data allows for the deduction of a reaction temperature. For the representative cork ablator investigated at the present conditions, the progression rate of the pyrolysis layer is determined to 0.0285 mm/s and pyrolysis temperature is 770 or 737 K, depending on the pre-existing conditions. It is found that the novel device is ideally suited for volume process imaging.

  5. Utilizing Proton Resonance Frequency of Isotopes Materials for Ultra-Precise Temperature Measurement: A Review

    Directory of Open Access Journals (Sweden)

    Abdullah Monis Abdulmanan

    2017-01-01

    Full Text Available High energy management in nuclear system and refractory metals productions are equipped with challenging procedures in terms of precise and remote controlling. In order to predict occurrence of contamination and avoidance of huge damages, there are often difficulties to access the equipment during their operation. In addition, estimating the precise and remote nucleation critical temperature of decay and growth of radioactive materials in the nuclear system has also proven to be a great challenge. Other than that, the eutectic crystallization temperature of the refractory metals during production also need to provide a precise estimation. However, it has been understood that the conventional temperature sensors are yet to be applicable to work precisely in such harsh environments. On the other hand, proton resonance frequency thermometry phenomenon have not been utilized or developed to serve as temperature sensors; despite the fact that they are capable to measure temperature in quantum level. Therefore, this article provides a review of the prior art on proton resonance frequency thermometry with its application and reliability, and elaborates on the trajectory of ultra-precise temperature measurement as the latest development.

  6. The stress corrosion resistance and the cryogenic temperature mechanical properties of annealed Nitronic 60 bar material

    Science.gov (United States)

    Montano, J. W. L.

    1977-01-01

    Ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of annealed, straightened, and centerless ground Nitronic 60 stainless steel alloy bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing strength with decreasing temperature to -196 C. Below liquid nitrogen temperature the smooth tensile and notched tensile strengths decreased slightly while the elongation and reduction of area decreased drastically. The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens and transverse C-ring specimens exposed to: alternate immersion in a 3.5% NaCl bath; humidity cabinet; and a 5% salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack. Approximately 3/4 of the transverse C-rings exposed to alternate immersion and to salt spray experienced a pitting attack on the top and bottom ends. Additional stress corrosion tests were performed on transverse tensile specimens. No failures occurred in the 90% stressed specimens exposed for 90 days in the alternate immersion and salt spray environments

  7. 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.

  8. 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.

  9. Research on CdZnTe and Other Novel Room Temperature Gamma Ray Spectrometer Materials

    Energy Technology Data Exchange (ETDEWEB)

    Arnold Burger; Michael gGoza; Yunlong Cui; Utpal N. Roy; M. Guo

    2007-05-05

    Room temperature gamma-ray spectrometers are being developed for a number of years for national security applications where high sensitivity, low operating power and compactness are indispensable. The technology has matured now to the point where large volume (several cubic centimeters) and high energy resolution (approximately 1% at 660 eV) of gamma photons, are becoming available for their incorporation into portable systems for remote sensing of signatures from nuclear materials.

  10. Utilizing Proton Resonance Frequency of Isotopes Materials for Ultra-Precise Temperature Measurement: A Review

    OpenAIRE

    Abdullah Monis Abdulmanan; Albarody Thar M. Badri; Yusoff Puteri Sri M. Bt Megat

    2017-01-01

    High energy management in nuclear system and refractory metals productions are equipped with challenging procedures in terms of precise and remote controlling. In order to predict occurrence of contamination and avoidance of huge damages, there are often difficulties to access the equipment during their operation. In addition, estimating the precise and remote nucleation critical temperature of decay and growth of radioactive materials in the nuclear system has also proven to be a great chall...

  11. 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.

  12. Microscale polymer bottles corked with a phase-change material for temperature-controlled release.

    Science.gov (United States)

    Hyun, Dong Choon; Lu, Ping; Choi, Sang-Il; Jeong, Unyong; Xia, Younan

    2013-09-27

    Keep your wine chilled! Microscale polystyrene (PS) bottles are loaded with dye molecules and then corked with a phase-change material (PCM). When the temperature is raised beyond its melting point, the PCM quickly melts and triggers an instant release of the encapsulated dye. The release profiles can be manipulated by using a binary mixture of PCMs with different melting points. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. DEVELOPMENT OF GREEN’S FUNCTION APPROACH CONSIDERING TEMPERATURE-DEPENDENT MATERIAL PROPERTIES AND ITS APPLICATION

    Directory of Open Access Journals (Sweden)

    HAN-OK KO

    2014-02-01

    Full Text Available About 40% of reactors in the world are being operated beyond design life or are approaching the end of their life cycle. During long-term operation, various degradation mechanisms occur. Fatigue caused by alternating operational stresses in terms of temperature or pressure change is an important damage mechanism in continued operation of nuclear power plants. To monitor the fatigue damage of components, Fatigue Monitoring System (FMS has been installed. Most FMSs have used Green's Function Approach (GFA to calculate the thermal stresses rapidly. However, if temperature-dependent material properties are used in a detailed FEM, there is a maximum peak stress discrepancy between a conventional GFA and a detailed FEM because constant material properties are used in a conventional method. Therefore, if a conventional method is used in the fatigue evaluation, thermal stresses for various operating cycles may be calculated incorrectly and it may lead to an unreliable estimation. So, in this paper, the modified GFA which can consider temperature-dependent material properties is proposed by using an artificial neural network and weight factor. To verify the proposed method, thermal stresses by the new method are compared with those by FEM. Finally, pros and cons of the new method as well as technical findings from the assessment are discussed.

  14. Frictional Performance and Temperature Rise of a Mining Nonasbestos Brake Material during Emergency Braking

    Directory of Open Access Journals (Sweden)

    Jiusheng Bao

    2015-01-01

    Full Text Available By simulating emergency braking conditions of mine hoisters, tribological experiments of a mining nonasbestos brake material sliding on E355CC steel friction disc investigated a pad-on-disc friction tester. It is shown that, under combined influence of braking velocity and pressure, the lubricating film and micro-convex-apices on wear surface would have complex physicochemical reactions which make the instant friction coefficient rise gradually while the instant surface temperature rises first and then falls. With the antifriction effect from lubricating film and the desquamating of composite materials, the mean friction coefficient decreases first, then rises, and decreases again with the increasing of initial braking velocity. And with the existence of micro-convex-apices and variation from increment ratio of load and actual contacting area, it rises first and then falls with the increasing of braking pressure. However, the mean surface temperature rises obviously with the increasing of both initial braking velocity and braking pressure for growth of transformed kinetic energy. It is considered that the friction coefficient cannot be considered as a constant when designing brake devices for mine hoisters. And special attention should be paid to the serious influence of surface temperature on tribological performance of brake material during emergency braking.

  15. 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.

  16. Temperature Regulation of Photovoltaic Module Using Phase Change Material: A Numerical Analysis and Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Hasan Mahamudul

    2016-01-01

    Full Text Available This work represents an effective design of a temperature regulated PV module by integrating phase change materials for Malaysian weather condition. Through the numerical analysis and experimental investigation it has been shown that if a PCM layer of width 0.02 m of RT 35 is used as a cooling arrangement with a PV module, the surface temperature of the module is reduced by 10°C, which remains constant for a period of 4–6 hours. This reduction of temperature implies the increase in conversion efficiency of the module. Experiment as well as investigation has been carried out considering typical Malaysian weather. Obtained result has been validated by using experimental prototype and comparative analysis.

  17. Low temperature grown GaNAsSb: A promising material for photoconductive switch application

    Energy Technology Data Exchange (ETDEWEB)

    Tan, K. H.; Yoon, S. F.; Wicaksono, S.; Loke, W. K.; Li, D. S. [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); Saadsaoud, N.; Tripon-Canseliet, C. [Laboratoire d' Electronique et Electromagnétisme, Pierre and Marie Curie University, 4 Place Jussieu, 75005 Paris (France); Lampin, J. F.; Decoster, D. [Institute of Electronics, Microelectronics and Nanotechnology (IEMN), UMR CNRS 8520, Universite des Sciences et Technologies de Lille, BP 60069, 59652 Villeneuve d' Ascq Cedex (France); Chazelas, J. [Thales Airborne Systems, 2 Avenue Gay Lussac, 78852 Elancourt (France)

    2013-09-09

    We report a photoconductive switch using low temperature grown GaNAsSb as the active material. The GaNAsSb layer was grown at 200 °C by molecular beam epitaxy in conjunction with a radio frequency plasma-assisted nitrogen source and a valved antimony cracker source. The low temperature growth of the GaNAsSb layer increased the dark resistivity of the switch and shortened the carrier lifetime. The switch exhibited a dark resistivity of 10{sup 7} Ω cm, a photo-absorption of up to 2.1 μm, and a carrier lifetime of ∼1.3 ps. These results strongly support the suitability of low temperature grown GaNAsSb in the photoconductive switch application.

  18. Effects of pressure and temperature on thermal contact resistance between different materials

    Directory of Open Access Journals (Sweden)

    Zhao Zhe

    2015-01-01

    Full Text Available To explore whether pressure and temperature can affect thermal contact resistance, we have proposed a new experimental approach for measurement of the thermal contact resistance. Taking the thermal contact resistance between phenolic resin and carbon-carbon composites, cuprum, and aluminum as the examples, the influence of the thermal contact resistance between specimens under pressure is tested by experiment. Two groups of experiments are performed and then an analysis on influencing factors of the thermal contact resistance is presented in this paper. The experimental results reveal that the thermal contact resistance depends not only on the thermal conductivity coefficient of materials, but on the interfacial temperature and pressure. Furthermore, the thermal contact resistance between cuprum and aluminum is more sensitive to pressure and temperature than that between phenolic resin and carbon-carbon composites.

  19. 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.

  20. Reduction of cyanogenic glycosides by extrusion - influence of temperature and moisture content of the processed material

    Directory of Open Access Journals (Sweden)

    Čolović Dušica S.

    2015-01-01

    Full Text Available Тhe paper presents results of the investigation of the influence of extrusion temperature and moisture content of treated material on the reduction of cyanogenic glycosides (CGs in linseed-based co-extrudate. CGs are the major limitation of the effective usage of linseed in animal nutrition. Hence, some technological process must be applied for detoxification of linseed before its application as a nutrient. Extrusion process has demonstrated several advantages in reducing the present CGs, since it combines the influences of heating, shearing, high pressure, mixing, etc. According to obtained results, the increase in both temperature and moisture content of the starting mixture decreased the content of CGs in the processed material. HCN content, as a measurement of GCs presence, ranged from 25.42 mg/kg, recorded at the moisture content of 11.5%, to 126 mg/kg, detected at the lowest moisture content of 7%. It seems that moisture content and temperature had the impact on HCN content of equal importance. However, the influence of extrusion parameters other than temperature and moisture content could not be neglected. Therefore, the impact of individual factors has to be tested together. [Projekat Ministarstva nauke Republike Srbije, br. III 46012

  1. MATERIAL DEPENDENCE OF TEMPERATURE DISTRIBUTION IN MULTI-LAYER MULTI-METAL COOKWARE

    Directory of Open Access Journals (Sweden)

    MOHAMMADREZA SEDIGH

    2017-09-01

    Full Text Available Laminated structure is becoming more popular in cookware markets; however, there seems to be a lack of enough scientific studies to evaluate its pros and cons, and to show that how it functions. A numerical model using a finite element method with temperature-dependent material properties has been performed to investigate material and layer dependence of temperature distribution in multi-layer multi-metal plate exposed to irregular heating. Behavior of two parameters including mean temperature value and uniformity on the inner surface of plate under variations of thermal properties and geometrical conditions have been studied. The results indicate that conductive metals used as first layer in bi-layer plates have better thermal performance than those used in the second layer. In addition, since cookware manufacturers increasingly prefer to use all-clad aluminium plate, recently, this structure is analysed in the present study as well. The results show all-clad copper and aluminum plate possesses lower temperature gradient compared with single layer aluminum and all-clad aluminum core plates.

  2. Numerical Model and Analysis of Peak Temperature Reduction in LiFePO4 Battery Packs Using Phase Change Materials

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2013-01-01

    Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials......Numerical model and analysis of peak temperature reduction in LiFePO4 battery packs using phase change materials...

  3. 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.

  4. Thermal buffering performance of composite phase change materials applied in low-temperature protective garments

    Science.gov (United States)

    Yang, Kai; Jiao, Mingli; Yu, Yuanyuan; Zhu, Xueying; Liu, Rangtong; Cao, Jian

    2017-07-01

    Phase change material (PCM) is increasingly being applied in the manufacturing of functional thermo-regulated textiles and garments. This paper investigated the thermal buffering performance of different composite PCMs which are suitable for the application in functional low-temperature protective garments. First, according to the criteria selecting PCM for functional textiles/garments, three kinds of pure PCM were selected as samples, which were n-hexadecane, n-octadecane and n-eicosane. To get the adjustable phase change temperature range and higher phase change enthalpy, three kinds of composite PCM were prepared using the above pure PCM. To evaluate the thermal buffering performance of different composite PCM samples, the simulated low-temperature experiments were performed in the climate chamber, and the skin temperature variation curves in three different low temperature conditions were obtained. Finally composite PCM samples’ thermal buffering time, thermal buffering capacity and thermal buffering efficiency were calculated. Results show that the comprehensive thermal buffering performance of n-octadecane and n-eicosane composite PCM is the best.

  5. 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.

  6. A materials perspective on Li-ion batteries at extreme temperatures

    Science.gov (United States)

    Rodrigues, Marco-Tulio F.; Babu, Ganguli; Gullapalli, Hemtej; Kalaga, Kaushik; Sayed, Farheen N.; Kato, Keiko; Joyner, Jarin; Ajayan, Pulickel M.

    2017-08-01

    With the continuous upsurge in demand for energy storage, batteries are increasingly required to operate under extreme environmental conditions. Although they are at the technological forefront, Li-ion batteries have long been limited to room temperature, as internal phenomena during their operation cause thermal fluctuations. This has been the reason for many battery explosions in recent consumer products. While traditional efforts to address these issues focused on thermal management strategies, the performance and safety of Li-ion batteries at both low (60 °C) temperatures are inherently related to their respective components, such as electrode and electrolyte materials and the so-called solid-electrolyte interphases. This Review examines recent research that considers thermal tolerance of Li-ion batteries from a materials perspective, spanning a wide temperature spectrum (-60 °C to 150 °C). The structural stability of promising cathodes, issues with anode passivation, and the competency of various electrolyte, binder and current collectors are compared for their thermal workability. The possibilities offered by each of these cell components could extend the environmental frontiers of commercial Li-ion batteries.

  7. Characterization of VOC Emission from Materials in Vehicular Environment at Varied Temperatures: Correlation Development and Validation

    Science.gov (United States)

    Xiong, Jianyin; Yang, Tao; Tan, Jianwei; Li, Lan; Ge, Yunshan

    2015-01-01

    The steady state VOC concentration in automobile cabin is taken as a good indicator to characterize the material emission behaviors and evaluate the vehicular air quality. Most studies in this field focus on experimental investigation while theoretical analysis is lacking. In this paper we firstly develop a simplified physical model to describe the VOC emission from automobile materials, and then derive a theoretical correlation between the steady state cabin VOC concentration (Ca) and temperature (T), which indicates that the logarithm of Ca/T0.75 is in a linear relationship with 1/T. Experiments of chemical emissions in three car cabins at different temperatures (24°C, 29°C, 35°C) were conducted. Eight VOCs specified in the Chinese National Standard GB/T 27630–2011 were taken for analysis. The good agreement between the correlation and experimental results from our tests, as well as the data taken from literature demonstrates the effectiveness of the derived correlation. Further study indicates that the slope and intercept of the correlation follows linear association. With the derived correlation, the steady state cabin VOC concentration different from the test conditions can be conveniently obtained. This study should be helpful for analyzing temperature-dependent emission phenomena in automobiles and predicting associated health risks. PMID:26452146

  8. 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.

  9. Characterization of VOC Emission from Materials in Vehicular Environment at Varied Temperatures: Correlation Development and Validation.

    Science.gov (United States)

    Xiong, Jianyin; Yang, Tao; Tan, Jianwei; Li, Lan; Ge, Yunshan

    2015-01-01

    The steady state VOC concentration in automobile cabin is taken as a good indicator to characterize the material emission behaviors and evaluate the vehicular air quality. Most studies in this field focus on experimental investigation while theoretical analysis is lacking. In this paper we firstly develop a simplified physical model to describe the VOC emission from automobile materials, and then derive a theoretical correlation between the steady state cabin VOC concentration (Ca) and temperature (T), which indicates that the logarithm of Ca/T0.75 is in a linear relationship with 1/T. Experiments of chemical emissions in three car cabins at different temperatures (24°C, 29°C, 35°C) were conducted. Eight VOCs specified in the Chinese National Standard GB/T 27630-2011 were taken for analysis. The good agreement between the correlation and experimental results from our tests, as well as the data taken from literature demonstrates the effectiveness of the derived correlation. Further study indicates that the slope and intercept of the correlation follows linear association. With the derived correlation, the steady state cabin VOC concentration different from the test conditions can be conveniently obtained. This study should be helpful for analyzing temperature-dependent emission phenomena in automobiles and predicting associated health risks.

  10. Characterization of VOC Emission from Materials in Vehicular Environment at Varied Temperatures: Correlation Development and Validation.

    Directory of Open Access Journals (Sweden)

    Jianyin Xiong

    Full Text Available The steady state VOC concentration in automobile cabin is taken as a good indicator to characterize the material emission behaviors and evaluate the vehicular air quality. Most studies in this field focus on experimental investigation while theoretical analysis is lacking. In this paper we firstly develop a simplified physical model to describe the VOC emission from automobile materials, and then derive a theoretical correlation between the steady state cabin VOC concentration (Ca and temperature (T, which indicates that the logarithm of Ca/T0.75 is in a linear relationship with 1/T. Experiments of chemical emissions in three car cabins at different temperatures (24°C, 29°C, 35°C were conducted. Eight VOCs specified in the Chinese National Standard GB/T 27630-2011 were taken for analysis. The good agreement between the correlation and experimental results from our tests, as well as the data taken from literature demonstrates the effectiveness of the derived correlation. Further study indicates that the slope and intercept of the correlation follows linear association. With the derived correlation, the steady state cabin VOC concentration different from the test conditions can be conveniently obtained. This study should be helpful for analyzing temperature-dependent emission phenomena in automobiles and predicting associated health risks.

  11. Development of a Low Temperature Irradiation Capsule for Research Reactor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Choo, Kee Nam; Cho, Man Soon; Lee, Cheol Yong; Yang, Sung Woo; Shin, Yoon Taek; Park, Seng Jae; Kang, Suk Hoon; Kang, Young Hwan; Park, Sang Jun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-07-01

    A new capsule design was prepared and tested at HANARO for a neutron irradiation of core materials of research reactors as a part of the research reactor development project. Irradiation testing of the materials including graphite, beryllium, and zircaloy-4 that are supposed to be used as core materials in research reactors was required for irradiation at up to 8 reactor operation cycles at low temperature (<100 .deg. C). Therefore, three instrumented capsules were designed and fabricated for an evaluation of the neutron irradiation properties of the core materials (Graphite, Be, Zircaloy-4) of research reactors. The capsules were first designed and fabricated to irradiate materials at low temperature (<100 .deg. C) for a long cycle of 8 irradiation cycles at HANARO. Therefore, the safety of the new designed capsule should be fully checked before irradiation testing. Out-pile performance and endurance testing before HANARO irradiation testing was performed using a capsule under a 110% condition of a reactor coolant flow amount. The structural integrity of the capsule was analyzed in terms of a vibration-induced fatigue cracking of a rod tip of the capsule that is suspected to be the most vulnerable part of a capsule. Another two capsules were irradiated at HANARO for 4 cycles, and one capsule was transferred to a hot cell to examine the integrity of the rod tip of the capsule. After confirming the soundness of the 4 cycle-irradiated capsule, the remaining capsule was irradiated at up to 8 cycles at HANARO. Based on the structural integrity analysis of the capsule, an improved capsule design will be suggested for a longer irradiation test at HANARO.

  12. Biological and Biomimetic Low-Temperature Routes to Materials for Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Morse, Daniel E. [Univ. of California, Santa Barbara, CA (United States). Inst. for Collaborative Biotechnologies

    2016-08-29

    New materials are needed to significantly improve the efficiencies of energy harnessing, transduction and storage, yet the synthesis of advanced composites and multi-metallic semiconductors with nanostructures optimized for these functions remains poorly understood and even less well controlled. To help address this need, we proposed three goals: (1) to further investigate the hierarchical structure of the biologically synthesized silica comprising the skeletal spicules of sponges that we discovered, to better resolve the role and mechanism of templating by the hierarchically assembled silicatein protein filament; (2) to extend our molecular and genetic analyses and engineering of silicatein, the self-assembling, structure-directing, silica-synthesizing enzyme we discovered and characterized, to better understand and manipulate the catalysis and templating of semiconductor synthesis,; and (3) to further investigate, scale up and harness the biologically inspired, low-temperature, kinetically controlled catalytic synthesis method we developed (based on the mechanism we discovered in silicatein) to investigate the kinetic control of the structure-function relationships in magnetic materials, and develop new materials for energy applications. The bio-inspired catalytic synthesis method we have developed is low-cost, low temperature, and operates without the use of polluting chemicals. In addition to direct applications for improvement of batteries and fuel cells, the broader impact of this research includes a deeper fundamental understanding of the factors governing kinetically controlled synthesis and its control of the emergent nanostructure and performance of a wide range of nanomaterials for energy applications.

  13. 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)

  14. 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.

  15. 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...

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. Development of a low temperature phase change material package. [for spacecraft thermal control

    Science.gov (United States)

    Brennan, P. J.; Suelau, H. J.; Mcintosh, R.

    1977-01-01

    Test data obtained for a low temperature phase change material (PCM) canisters are presented. The canister was designed to provide up to 30 w-hrs of storage capacity at approximately -90 C with an overall thermal conductance which is greater than 8 w/deg C. N-heptane which is an n-paraffin and has a -90.6 C freezing point was used as the working fluid. The canister was fabricated from aluminum and has an aluminum honeycomb core. Its void volume permits service temperatures up to 70 C. Results obtained from component and system's tests indicate well defined melting and freezing points which are repeatable and within 1 C of each other. Subcooling effects are less than 0.5 C and are essentially negligible. Measured storage capacities are within 94 to 88% the theoretical.

  1. 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.

  2. Calibration of temperature measurement by infrared pyrometry in microwave heating of powder materials: an exothermic reaction based approach.

    Science.gov (United States)

    Luo, S D; Yang, Y F; Schaffer, G B; Qian, M

    2013-01-01

    Accurate temperature measurement remains a challenge for microwave heating of powder materials. We propose a temperature calibration method based on exothermic reactions and the resultant thermal runaway that occurs during microwave heating. The approach was demonstrated on microwave heating of four titanium alloys. Differential scanning calorimetry was used to determine the threshold reaction temperature for each selected titanium alloy. This served as a standard for the microwave heating of these titanium alloys. Infrared pyrometric temperature measurements were then calibrated by comparing the starting temperature of each thermal runaway event with the threshold reaction temperature.

  3. Ag-doped manganite nanoparticles: new materials for temperature-controlled medical hyperthermia.

    Science.gov (United States)

    Melnikov, O V; Gorbenko, O Yu; Markelova, M N; Kaul, A R; Atsarkin, V A; Demidov, V V; Soto, C; Roy, E J; Odintsov, B M

    2009-12-15

    The purpose of this study was to introduce newly synthesized nanomaterials as an alternative to superparamagnetic ironoxide based particles (SPIO) and thus to launch a new platform for highly controllable hyperthermia cancer therapy and imaging. The new material that forms the basis for this article is lanthanum manganite particles with silver ions inserted into the perovskite lattice: La(1-x)Ag(x)MnO(3+delta). Adjusting the silver doping level, it is possible to control the Curie temperature (T(c)) in the hyperthermia range of interest (41-44 degrees C). A new class of nanoparticles based on silver-doped manganites La(1-x)Ag(x)MnO(3+delta) is suggested. New nanoparticles are stable, and their properties were not affected by the typical ambient conditions in the living tissue. It is possible to monitor the particle uptake and retention by MRI. When these particles are placed into an alternating magnetic field, their temperature increases to the definite value near T(c) and then remains constant if the magnetic field is maintained. During the hyperthermia procedure, the temperature can be restricted, thereby preventing the necrosis of normal tissue. A new class of nanoparticles based on silver-doped manganites La(1-x)Ag(x)MnO(3+delta) was suggested. Ag-doped perovskite manganites particles clearly demonstrated the effect of adjustable Curie temperature necessary for highly controllable cellular hyperthermia. The magnetic relaxation properties of the particles are comparable with that of SPIO, and so we were able to monitor the particle movement and retention by MRI. Thus, the new material combines the MRI contrast enhancement capability with targeted hyperthermia treatment.

  4. Influence of the temperature on materials electric behaviour: Understanding and students’ learning difficulties

    Directory of Open Access Journals (Sweden)

    Antonio García Carmona

    2006-03-01

    Full Text Available In this article, we defend that in the teaching/learning of the electricity, its contents must be associa ted with contents concerning the structure and behaviour of the matter. Thus, it is possible to understand some electricity topics as the influence of the temperature on electric behaviour of materials. In this sense, we propose a conceptual framework for its teaching, coherent with the Spanish Physics and Chemistry curriculum of Secondary Education. Likewise, we show the results of a research carried out with 60 pupils (age 14-15, about theirs understanding levels and theirs learning difficulties regarding considered topic.

  5. Phase Change Material for Temperature Control of Imager or Sounder on GOES Type Satellites in GEO

    Science.gov (United States)

    Choi, Michael K.

    2014-01-01

    This paper uses phase change material (PCM) in the scan cavity of an imager or sounder on satellites in geostationary orbit (GEO) to maintain the telescope temperature stable. When sunlight enters the scan aperture, solar heating causes the PCM to melt. When sunlight stops entering the scan aperture, the PCM releases the thermal energy stored to keep the components in the telescope warm. It has no moving parts or bimetallic springs. It reduces heater power required to make up the heat lost by radiation to space through the aperture. It is an attractive thermal control option to a radiator with a louver and a sunshade.

  6. Determination of Material Constitutive Laws for Inconel 718 Superalloy Under Different Strain Rates and Working Temperatures

    Science.gov (United States)

    Grzesik, W.; Niesłony, P.; Laskowski, P.

    2017-10-01

    In this paper, a special procedure for the prediction of parameters of the Johnson-Cook constitutive material models is proposed based on the experimental data and specially developed MATLAB scripts which allow advanced modeling of complex 3D response surfaces. Experimental investigations concern two various strain rates of 10-3 and 101 1/s and the testing temperature ranging from the ambient up to 700 °C. As a result, a set of mathematical equations which fit the experimental data is determined. The applicability of the experimentally derived constitutive models to the FEM modeling of real machining processes of Inconel 718 alloy is verified.

  7. Magnetic refrigeration at room temperature - from magnetocaloric materials to a prototype

    DEFF Research Database (Denmark)

    Kuhn, Luise Theil; Pryds, Nini; Bahl, Christian Robert Haffenden

    2011-01-01

    materials, their shaping and graded composition for technological use. Modelling the performance of a permanent magnet with optimum use of the flux and relatively low weight, and designing and constructing a prototype continuous magnetic refrigeration device have also been major tasks in the project......Based on the magnetocaloric effect, magnetic refrigeration at room temperature has for the past decade been a promising, environmentally friendly new energy technology predicted to have a significantly higher efficiency than the present conventional methods. However, so far only a few prototype...... refrigeration machines have been presented worldwide and there are still many scientific and technological challenges to be overcome. We report here on the MagCool project, which spans all the way from basic materials studies to the construction of a prototype. Emphasis has been on ceramic magnetocaloric...

  8. Numerical Simulation of Temperature Distribution and Material Flow During Friction Stir Welding 2017A Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Mimouni Oussama

    2016-01-01

    Full Text Available This study describes the use of fluid dynamic code, FLUENT to model the flow of metal in the AA2017A case around the welding tool pin (FSW. A standard threaded tool profile is used for the analysis of phenomena during welding such as heat generation and flow of the material are included. The main objective is to gain a better understanding of the flow of material around a tool. The model showed a large number of phenomena similar to those of the real process. The model has also generated a sufficient amount of heat, which leads to a good estimate of the junction temperature. These results were obtained using a viscosity which is near the solidus softening.

  9. OWL: A scalable Monte Carlo simulation suite for finite-temperature study of materials

    Science.gov (United States)

    Li, Ying Wai; Yuk, Simuck F.; Cooper, Valentino R.; Eisenbach, Markus; Odbadrakh, Khorgolkhuu

    The OWL suite is a simulation package for performing large-scale Monte Carlo simulations. Its object-oriented, modular design enables it to interface with various external packages for energy evaluations. It is therefore applicable to study the finite-temperature properties for a wide range of systems: from simple classical spin models to materials where the energy is evaluated by ab initio methods. This scheme not only allows for the study of thermodynamic properties based on first-principles statistical mechanics, it also provides a means for massive, multi-level parallelism to fully exploit the capacity of modern heterogeneous computer architectures. We will demonstrate how improved strong and weak scaling is achieved by employing novel, parallel and scalable Monte Carlo algorithms, as well as the applications of OWL to a few selected frontier materials research problems. This research was supported by the Office of Science of the Department of Energy under contract DE-AC05-00OR22725.

  10. 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.

  11. 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.

  12. 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.

  13. Detonation shock dynamics calibration for pBX 9502 with temperature, density, and material lot variations

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Larry G [Los Alamos National Laboratory; Aslam, Tariq D [Los Alamos National Laboratory

    2010-01-01

    We present a methodology for scaling the detonation shock dynamics D{sub n}[{kappa}] calibration function to accommodate variations in the HE starting material. We apply our model to the insensitive TATB-based explosive PBX 9502, for which we have enough front curvature rate stick data to characterize three material attributes: initial temperature T{sub 0}, nominal density {rho}{sub 0}, and manufacturing lot (representing different microstructures). A useful feature of the model is that it returns an absolute estimate for the reaction zone thickness, {delta}. Lacking demonstrated material metrics(s), we express microstructural variation indirectly, in terms of its effect on {delta}. This results in a D{sub n}[{kappa}] function that depends on T{sub 0}, {rho}{sub 0}, and {delta}. After examining the separate effects of each parameter on D{sub n}[{kappa}], we compute an arc geometry as a validation problem. We compare the calculation to a PBX 9502 arc experiment that was pressed from one of the calibrated HE lots. The agreement between the model and experiment is excellent. We compute worst, nominal, and best-performing material parameter combinations to show how much difference accrues throughout the arc.

  14. 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...

  15. Infrared spectroscopy of Mercury analogue materials under simulated Mercury surface temperature conditions

    Science.gov (United States)

    Reitze, Maximilian; Morlok, Andreas; Hiesinger, Harald; Weber, Iris; Stojic, Aleksandra

    2017-04-01

    Infrared spectroscopy is a powerful technique for the exploration of planetary surfaces with remote sensing observations [e.g., 1]. The MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer) instrument onboard the BepiColombo spacecraft is designed to explore the surface mineralogy of Mercury in the wavelength region from 7 μ m to 14 μ m [2]. Mercury's surface reaches dayside temperatures of about 700 K [3]. It is well known that bondings between atoms change with temperature, resulting in infrared spectra changes with temperature [4]. In particular, rock-forming minerals like silicates show distinct absorption bands in the infrared due to molecular vibrations, for example, of Si-O bondings [4]. To accurately understand and correctly interpret returned MERTIS data, it is necessary to collect laboratory data of analogue materials under condition similar to Mercury [5]. It is known from previous investigations [5] that the Reststrahlenbands of olivine shift with temperature. In this work we report on temperature effects on Mercury analogue materials in ambient air. At the IRIS (Infrared & Raman for Interplanetary Spectroscopy) laboratory in Münster we used a Bruker VERTEX 70v IR spectrometer together with a Harrick heating stage in a Praying Mantis Diffuse Reflectance Accessory to measure mid-infrared reflectance of mineral powder samples with different grain sizes at increasing temperatures. We report on our spectral results for a natural olivine with Fo91 with a grain size range between 63 μ m and 125 μ m as well as a natural labradorite with a grain size range between 90 μ m and 125 μ m. Spectra were collected at 26, 75, 150, 200, 250, 300, and 350 degrees Celsius with a liquid nitrogen cooled MCT detector under normal ambient pressure. To ensure complete thermal equilibrium of our measured samples, we heated them to higher temperatures and subsequently cooled them to the temperatures at which the spectra were taken. For background calibration, we

  16. Embedded optical probes for simultaneous pressure and temperature measurement of materials in extreme conditions

    Science.gov (United States)

    Sandberg, R. L.; Rodriguez, G.; Gibson, L. L.; Dattelbaum, D. M.; Stevens, G. D.; Grover, M.; Lalone, B. M.; Udd, E.

    2014-05-01

    We present recent efforts at Los Alamos National Laboratory (LANL) to develop sensors for simultaneous, in situ pressure and temperature measurements under dynamic conditions by using an all-optical fiber-based approach. While similar tests have been done previously in deflagration-to-detonation tests (DDT), where pressure and temperature were measured to 82 kbar and 400°C simultaneously, here we demonstrate the use of embedded fiber grating sensors to obtain high temporal resolution, in situ pressure measurements in inert materials. We present two experimental demonstrations of pressure measurements: (1) under precise shock loading from a gas-gun driven plate impact and (2) under high explosive driven shock in a water filled vessel. The system capitalizes on existing telecom components and fast transient digitizing recording technology. It operates as a relatively inexpensive embedded probe (single-mode 1550 nm fiber-based Bragg grating) that provides a continuous fast pressure record during shock and/or detonation. By applying well-controlled shock wave pressure profiles to these inert materials, we study the dynamic pressure response of embedded fiber Bragg gratings to extract pressure amplitude of the shock wave and compare our results with particle velocity wave profiles measured simultaneously.

  17. 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.

  18. Temperature profile measurement of graphite material using a CO{sub 2} laser

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Payal; Sarma, Arun [Pandit Deendayal Petroleum University, Raisan, Gandhinagar-382007, Gujarat (India); Ghosh, Joydeep; Pandya, Shwetang; Pandya, Santosh; Choudhuri, Paritosh; Govindarajan, J [Institute for Plasma Research, Bhat, Gandhinagar-382428, Gujarat (India); Schrittwieser, C Ionita; Schrittwieser, Roman, E-mail: arun.sarma@spt.pdpu.ac.i [Institute for Ion Physics, University of Innsbruck, Innsbruck (Austria)

    2010-11-15

    Emissive probes have been used for the direct measurement of plasma potential in many plasma devices and different approaches have been introduced to measure plasma potential using emissive probes. But the biggest disadvantage of the emissive probe is its short lifespan due to its self-arrangement and different plasma environment. For example, filament emissive probes cannot be used in high-temperature plasma devices. A few initiatives have begun to measure the plasma potential by using a laser-heated emissive probe. In these cases, mostly graphite and LaB{sub 6} are being used as a probe tip to emit electrons by heating them with a laser light. However, very few studies aiming to understand the mechanism of the heating process of the graphite material have been performed. The heating dynamics of the graphite material heated by a CW CO{sub 2} laser with a maximum power of 30 W have been investigated in this study. The in situ temperature of the probe tip has been measured by using an infrared camera. Complete theoretical and simulation models have been developed to understand the experimentally measured data. Further, the experimental results are compared with ANSYS simulations.

  19. Effect of temperature on composite sandwich structures subjected to low velocity impact. [aircraft construction materials

    Science.gov (United States)

    Sharma, A. V.

    1980-01-01

    The effect of low velocity projectile impact on sandwich-type structural components was investigated. The materials used in the fabrication of the impact surface were graphite-, Kevlar-, and boron-fibers with appropriate epoxy matrices. The testing of the specimens was performed at moderately low- and high-temperatures as well as at room temperature to assess the impact-initiated strength degradation of the laminates. Eleven laminates with different stacking sequences, orientations, and thicknesses were tested. The low energy projectile impact is considered to simulate the damage caused by runway debris, the dropping of the hand tools during servicing, etc., on the secondary aircraft structures fabricated with the composite materials. The results show the preload and the impact energy combinations necessary to cause catastrophic failure in the laminates tested. A set of faired curves indicating the failure thresholds is shown separately for the tension-and compression-loaded laminates. The specific-strengths and -modulii for the various laminates tested are also given.

  20. Novel solid – solid phase change material based on polyethylene glycol and cellulose used for temperature stabilisation

    Directory of Open Access Journals (Sweden)

    Wojda Marta

    2014-01-01

    Full Text Available Thermal management is one of crucial issues in the development of modern electronic devices. In the recent years interest in phase change materials (PCMs as alternative cooling possibility has increased significantly. Preliminary results concerning the research into possibility of the use of solid-solid phase change materials (S-S PCMs for stabilisation temperature of electronic devices has been presented in the paper. Novel solid-solid phase change material based on polyethylene glycol and cellulose has been synthesized. Attempt to improve its thermal conductivity has been taken. Material has been synthesized for the purpose of stabilisation of temperature of electronic devices.

  1. Development of film- and- fabric composite materials durability assessing methodology under time-dependent influences of temperature and solar radiation

    Science.gov (United States)

    Kayumov, R. A.; Muhamedova, I. Z.; Suleymanov, A. M.; Tazyukov, B. F.

    2016-11-01

    In this paper, we present the design of stress-strain state calculation and film-and- fabric composite materials durability under stresses and solar radiation. We have constructed a two-dimensional finite-state-element computer model of the deforming process of the low- level cell of film-and-fabric-based composite material for the evaluation of its durability which takes into account non-linear viscoelasticity, temperature variations, ageing of the material, the process of upbuilding of microdamage and photodegradation. Qualitative research of operational factors influence (UV, temperature) on film-and-fabric composite materials durability was conducted.

  2. Evaluation of temperature rise in a tissue mimicking material during HIFU exposure

    Energy Technology Data Exchange (ETDEWEB)

    Maruvada, S; Liu, Y; Herman, B A; Harris, G R, E-mail: subha.maruvada@fda.hhs.gov [Food and Drug Administration, Center for Devices and Radiological Health, 10903 New Hampshire Ave., Bldg., Silver Spring, MD 20993 (United States)

    2011-02-01

    In pre-clinical testing it is essential to characterize clinical high intensity focused ultrasound (HIFU) devices using tissue-mimicking materials (TMMs) with well known characteristics, including temperature rise and cavitation properties. The purpose of this study was to monitor cavitation behavior and correlate its effect with temperature rise in a HIFU TMM containing an embedded thermocouple. A 75-{mu}m fine wire thermocouple was embedded in a hydrogel-based TMM previously developed for HIFU. HIFU at 1.1 and 3.3 MHz was focused at the thermocouple junction. Focal pressures from 1-11 MPa were applied and the temperature profiles were recorded. Three hydrophones were used to monitor cavitation activity during sonication. A hydrophone confocal with the HIFU transducer and a cylindrical hydrophone lateral to the HIFU beam were used as passive cavitation detectors for spectral analysis of signals, and a needle hydrophone placed beyond the HIFU focus was used to record changes in the pressure amplitude due to blockage by bubbles at or near the focus. B-mode imaging scans were employed to visualize bubble presence during sonication. In a separate measurement, schlieren imaging was used to monitor the change in field distribution behind the TMM. All hydrophone methods correlated well with cavitation in the TMM.

  3. 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.

  4. 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.

  5. Comparison of thermistor linearization techniques for accurate temperature measurement in phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, S B; Kyriacou, P A, E-mail: p.kyriacou@city.ac.uk [School of Engineering and Mathematical Sciences, City University London, Northampton Square, London EC1V 0HB (United Kingdom)

    2011-08-17

    Alternate energy technologies are developing rapidly in the recent years. A significant part of this trend is the development of different phase change materials (PCMs). Proper utilization of PCMs requires accurate thermal characterization. There are several methodologies used in this field. This paper stresses the importance of accurate temperature measurements during the implementation of T-history method. Since the temperature sensor size is also important thermistors have been selected as the sensing modality. Two thermistor linearization techniques, one based on Wheatstone bridge and the other based on simple serial-parallel resistor connection, are compared in terms of achievable temperature accuracy through consideration of both, nonlinearity and self-heating errors. Proper calibration was performed before T-history measurement of RT21 (RUBITHERM (registered) GmbH) PCM. Measurement results suggest that the utilization of serial-parallel resistor connection gives better accuracy (less than {+-}0.1 deg. C) in comparison with the Wheatstone bridge based configuration (up to {+-}1.5 deg. C).

  6. Friction and wear studies on the temperature dependence of brake-pad materials containing brass

    Directory of Open Access Journals (Sweden)

    Eddoumy Fatima

    2013-11-01

    Full Text Available Brake pad materials for automobile applications are basically polymer matrix composites. Various reinforcing constituents used in brake pads are organic, metallic and ceramic fillers which play among others an important role on the mechanical and thermal properties, and the wear resistance at high temperature. Friction and wear depend on various parameters such as the micro-chemical structure of the pad and of the metallic counter-face, the rotation speed, the pressure, and the contact surface temperature (M.G. Jacko 1983. This latter parameter can be locally as high as 600 up to 1.500 ∘C depending on the brake type (M.G. Jacko 1983; Blau 2001. Thermal models have been developed to study interface effects at contacting surfaces (Majcherczak, Dufrenoy et al. 2007. Frictional energy can be dissipated through different mechanisms such as oxidation, rise in temperature, formation of wear particles, entropy changes associated to viscoelastic and viscoplastic deformation, and noise generation (Eddoumy, Addiego et al. 2011. Studies of friction brake show that more than 95% of the dissipated energy is transformed into heat (Kasem, Thevenet et al.; Majcherczak, Dufrenoy et al. 2007. Thermal analysis is therefore a primordial step in the study of brake systems since it provides thermo-mechanical properties (Majcherczak, Dufrenoy et al. 2007. The influence of the addition of metallic fibers on the performance of organic friction composites has been investigated using friction tests (Qu, Zhang et al. 2004. Benefits or limitations of the different fibers have been reported, however the issues of thermo-mechanical properties or effect of temperature on friction and wear behavior were not yet investigated (Bijwe, Kumar et al. 2008. No effort was done to correlate the thermo-mechanical and thermal properties with the friction and wear behavior. An important prerequisite is to get a good understanding on how brake materials behave. However, a link

  7. 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.

  8. Next-Generation Electrochemical Energy Materials for Intermediate Temperature Molten Oxide Fuel Cells and Ion Transport Molten Oxide Membranes.

    Science.gov (United States)

    Belousov, Valery V

    2017-02-21

    High temperature electrochemical devices such as solid oxide fuel cells (SOFCs) and oxygen separators based on ceramic materials are used for efficient energy conversion. These devices generally operate in the temperature range of 800-1000 °C. The high operating temperatures lead to accelerated degradation of the SOFC and oxygen separator materials. To solve this problem, the operating temperatures of these electrochemical devices must be lowered. However, lowering the temperature is accompanied by decreasing the ionic conductivity of fuel cell electrolyte and oxygen separator membrane. Therefore, there is a need to search for alternative electrolyte and membrane materials that have high ionic conductivity at lower temperatures. A great many opportunities exist for molten oxides as electrochemical energy materials. Because of their unique electrochemical properties, the molten oxide innovations can offer significant benefits for improving energy efficiency. In particular, the newly developed electrochemical molten oxide materials show high ionic conductivities at intermediate temperatures (600-800 °C) and could be used in molten oxide fuel cells (MOFCs) and molten oxide membranes (MOMs). The molten oxide materials containing both solid grains and liquid channels at the grain boundaries have advantages compared to the ceramic materials. For example, the molten oxide materials are ductile, which solves a problem of thermal incompatibility (difference in coefficient of thermal expansion, CTE). Besides, the outstanding oxygen selectivity of MOM materials allows us to separate ultrahigh purity oxygen from air. For their part, the MOFC electrolytes show the highest ionic conductivity at intermediate temperatures. To evaluate the potential of molten oxide materials for technological applications, the relationship between the microstructure of these materials and their transport and mechanical properties must be revealed. This Account summarizes the latest results on

  9. 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

    The catalyst system should fulfil the following conditions: (1) Low pressure drop, (2) Ignition of the fuel at the compressor outlet temperature, i.e. 300 - 400 deg C, (3) Resistance to thermal shocks, and (4) Resistance to sintering and deactivation for at least 1 year (8000 hours). As a single component can hardly retain all these properties, material science must then be combined with combustion technology and chemical reaction engineering. The work was then divided in four main tasks; material development, catalytic activity and kinetics measurement, mathematical modelling and design and engineering. The material development was devoted to the different components of a catalytic system, monolith, washcoat and active phase. The preparation method has proven to be of great importance with respect to the BET surface area of the prepared powder as well as the catalytic activity. A carbonate precipitation and a sol-gel procedure were developed at our laboratory. The use of modifiers in the sol-gel method has shown to affect the surface properties as well as the catalytic activity in ethanol and diesel combustion. Various catalytic materials have then been prepared: spinel, perovskite, hexaaluminate and pyrochlore. The hexaaluminate have the highest resistance to sintering in term of BET surface area when aged in 10% steam at temperature up to 1400 deg C for 4 hours. However, the LaAl{sub 11}O{sub 18} hexaaluminate does not have sufficient catalytic activity to ignite the fuel at 300-400 deg C. Substitution with transition metals have then been examined. In the case of ethanol combustion, the Mn-substituted La-hexaaluminate has a T{sub 50} (temperature for 50% conversion) of about 350 deg C. The noble metal-supported catalysts reveal a much higher activity with a T{sub 50} below 250 deg C. However their thermal stability may limit their use to temperatures below 900 deg C. The need of more thermal stable materials lead to the study of NZP-type material, yttrium

  10. Carcinogenic organic residual compounds readsorbed on thermally reduced graphene materials are released at low temperature.

    Science.gov (United States)

    Ambrosi, Adriano; Wong, Gwendeline K S; Webster, Richard D; Sofer, Zdeněk; Pumera, Martin

    2013-10-18

    The preliminary oxidation of graphite to graphite oxide followed by a thermal exfoliation is one of the methods most frequently employed in the preparation of graphene. Such thermally reduced graphene can be widely used for several applications that range from coatings to sensing device fabrication. It is therefore important to investigate in detail the fabrication procedure, the structural features of the resulting graphene, and its potential toxicological effects. Low-molecular-weight and carcinogenic compounds are known to be generated during the thermal reduction/exfoliation of graphite oxide. Such compounds are readsorbed onto the reduced material during the cooling process. We investigate here the composition of the organic compounds that are adsorbed onto the graphene material and show that they can be easily released during the following processing steps even at temperatures as low as 50 °C. Some of the released organic compounds are classified as highly carcinogenic. The results shown here are important not only from a chemical point of view to better understand the composition and properties of the graphene material produced, but also to bring attention to the potential toxicological effects that the synthesis itself or the post-production processes can cause. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. 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.

  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. Flow behaviour of autoclaved, 20% cold worked, Zr-2.5Nb alloy pressure tube material in the temperature range of room temperature to 800 °C

    Science.gov (United States)

    Dureja, A. K.; Sinha, S. K.; Srivastava, Ankit; Sinha, R. K.; Chakravartty, J. K.; Seshu, P.; Pawaskar, D. N.

    2011-05-01

    Pressure tube material of Indian Heavy Water Reactors is 20% cold-worked and stress relieved Zr-2.5Nb alloy. Inherent variability in the process parameters during the fabrication stages of pressure tube and also along the length of component have their effect on micro-structural and texture properties of the material, which in turn affect its strength parameters (yield strength and ultimate tensile strength) and flow characteristics. Data of tensile tests carried out in the temperature range from room temperature to 800 °C using the samples taken out from a single pressure tube have been used to develop correlations for characterizing the strength parameters' variation as a function of axial location along length of the tube and the test temperature. Applicability of Ramberg-Osgood, Holloman and Voce's correlations for defining the post yield behaviour of the material has been investigated. Effect of strain rate change on the deformation behaviour has also been studied.

  14. Standard Guide for Predicting Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials, E706 (IIF)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This guide presents a method for predicting reference transition temperature adjustments for irradiated light-water cooled power reactor pressure vessel materials based on Charpy V-notch 30-ftlbf (41-J) data. Radiation damage calculative procedures have been developed from a statistical analysis of an irradiated material database that was available as of May 2000. The embrittlement correlation used in this guide was developed using the following variables: copper and nickel contents, irradiation temperature, and neutron fluence. The form of the model was based on current understanding for two mechanisms of embrittlement: stable matrix damage (SMD) and copper-rich precipitation (CRP); saturation of copper effects (for different weld materials) was included. This guide is applicable for the following specific materials, copper, nickel, and phosphorus contents, range of irradiation temperature, and neutron fluence based on the overall database: 1.1.1 MaterialsA 533 Type B Class 1 and 2, A302 Grade B, A302 G...

  15. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials.

    Science.gov (United States)

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; Di, Chong-an; Zhu, Daoben

    2015-09-21

    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of sensors can be self-powered with outstanding sensing performance. The excellent sensing properties of MFSOTE-based devices, together with their unique advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  16. Flexible and self-powered temperature-pressure dual-parameter sensors using microstructure-frame-supported organic thermoelectric materials

    Science.gov (United States)

    Zhang, Fengjiao; Zang, Yaping; Huang, Dazhen; di, Chong-An; Zhu, Daoben

    2015-09-01

    Skin-like temperature- and pressure-sensing capabilities are essential features for the next generation of artificial intelligent products. Previous studies of e-skin and smart elements have focused on flexible pressure sensors, whereas the simultaneous and sensitive detection of temperature and pressure with a single device remains a challenge. Here we report developing flexible dual-parameter temperature-pressure sensors based on microstructure-frame-supported organic thermoelectric (MFSOTE) materials. The effective transduction of temperature and pressure stimuli into two independent electrical signals permits the instantaneous sensing of temperature and pressure with an accurate temperature resolution of advantages of low cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  17. 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

  18. 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.

  19. Volatile Organic Compound (VOC) emissions from feedlot pen surface materials as affected by within pen location, moisture, and temperature

    Science.gov (United States)

    A laboratory study was conducted to evaluate the effects of pen location, moisture, and temperature on emissions of volatile organic compounds (VOC) from surface materials obtained from feedlot pens where beef cattle were fed a diet containing 30% wet distillers grain plus solubles. Surface material...

  20. Exploration of the role of anions in the synthesis of Cr containing mesoporous materials at room temperature

    NARCIS (Netherlands)

    Mahony, L; Wu, C.M.; Kibombo, H.S.; Thiruppathi, E.; Baltrusaitis, Jonas; Rasalingam, S; Koodali, R.T.

    2013-01-01

    Chromium containing mesoporous silica materials were synthesized via a modified Stöber synthesis at room temperature. The chromium ion loading and the effect of counter ion in the synthesis were studied in detail. The mesoporous materials were extensively characterized by powder X-ray diffraction

  1. 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.

  2. Damage and etching of ultra low-k materials in fluorocarbon plasma at lowered temperatures

    Science.gov (United States)

    Lopaev, D. V.; Mankelevich, Yu A.; Rakhimova, T. V.; Zotovich, A. I.; Zyryanov, S. M.; Baklanov, M. R.

    2017-12-01

    SiOCH ULK films with k-value from 2.5 to 2.1 and porosity from 24 to 40% were etched in CHF3, CHF3  +  Ar, CF4 and CF4  +  Ar plasmas at  +15…‑120 °C with and without bias being applied. It was shown that the presence of Ar in gas mixture can significantly increase the damage of unetched ultra low-k (ULK) material (at sidewalls) due to the removal of  ‑CH3 groups from the film by VUV photons. It was also shown that etching and damage of the sidewalls by F atoms can be partially prevented by lowering the temperature of the sample.

  3. 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.

  4. An inverse problem of thickness design for bilayer textile materials under low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Xu Dinghua; Cheng Jianxin; Chen Yuanbo [Department of Mathematics, College of Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, Zhejiang (China); Ge Meibao, E-mail: dhxu6708@zstu.edu.cn [College of Sciences and Arts, Zhejiang Sci-Tech University, Hangzhou 311121, Zhejiang (China)

    2011-04-01

    The human heat-moisture-comfort level is mainly determined by heat and moisture transfer characteristics in clothing. With respect to the model of steady-state heat and moisture transfer through parallel pore textiles, we propose an inverse problem of thickness design for bilayer textile material under low temperature in this paper. Adopting the idea of regularization method, we formulate the inverse problem solving into a function minimization problem. Combining the finite difference method for ordinary differential equations with direct search method of one-dimensional minimization problems, we derive three kinds of iteration algorithms of regularized solution for the inverse problem of thickness design. Numerical simulation is achieved to verify the efficiency of proposed methods.

  5. 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.

  6. 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.

  7. Temperature dependent optical characterization of Ni-TiO2 thin films as potential photocatalytic material

    Directory of Open Access Journals (Sweden)

    Rajnarayan De

    2017-09-01

    Full Text Available Along with other transition metal doped titanium dioxide materials, Ni-TiO2 is considered to be one of the most efficient materials for catalytic applications due to its suitable energy band positions in the electronic structure. The present manuscript explores the possibility of improving the photocatalytic activity of RF magnetron sputtered Ni-TiO2 films upon heat treatment. Optical, structural and morphological and photocatalytic properties of the films have been investigated in detail for as deposited and heat treated samples. Evolution of refractive index (RI and total film thickness as estimated from spectroscopic ellipsometry characterization are found to be in agreement with the trend in density and total film thickness estimated from grazing incidence X-ray reflectivity measurement. Interestingly, the evolution of these macroscopic properties were found to be correlated with the corresponding microstructural modifications realized in terms of anatase to rutile phase transformation and appearance of a secondary phase namely NiTiO3 at high temperature. Corresponding morphological properties of the films were also found to be temperature dependent which leads to modifications in the grain structure. An appreciable reduction of optical band gap from 2.9 to 2.5 eV of Ni-TiO2 thin films was also observed as a result of post deposition heat treatment. Testing of photocatalytic activity of the films performed under UV illumination demonstrates heat treatment under atmospheric ambience to be an effective means to enhance the photocatalytic efficiency of transition metal doped titania samples.

  8. Predicting critical temperatures of iron(II) spin crossover materials: Density functional theory plus U approach

    Science.gov (United States)

    Zhang, Yachao

    2014-12-01

    A first-principles study of critical temperatures (Tc) of spin crossover (SCO) materials requires accurate description of the strongly correlated 3d electrons as well as much computational effort. This task is still a challenge for the widely used local density or generalized gradient approximations (LDA/GGA) and hybrid functionals. One remedy, termed density functional theory plus U (DFT+U) approach, introduces a Hubbard U term to deal with the localized electrons at marginal computational cost, while treats the delocalized electrons with LDA/GGA. Here, we employ the DFT+U approach to investigate the Tc of a pair of iron(II) SCO molecular crystals (α and β phase), where identical constituent molecules are packed in different ways. We first calculate the adiabatic high spin-low spin energy splitting ΔEHL and molecular vibrational frequencies in both spin states, then obtain the temperature dependent enthalpy and entropy changes (ΔH and ΔS), and finally extract Tc by exploiting the ΔH/T - T and ΔS - T relationships. The results are in agreement with experiment. Analysis of geometries and electronic structures shows that the local ligand field in the α phase is slightly weakened by the H-bondings involving the ligand atoms and the specific crystal packing style. We find that this effect is largely responsible for the difference in Tc of the two phases. This study shows the applicability of the DFT+U approach for predicting Tc of SCO materials, and provides a clear insight into the subtle influence of the crystal packing effects on SCO behavior.

  9. 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.

  10. 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.

  11. 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.

  12. Temperature dependence of spectroscopic and electrical properties of Cr(Fe):ZnSe laser active materials

    Science.gov (United States)

    Gafarov, Ozarfar; Watkins, Rick; Bernard, Chandler; Fedorov, Vladimir; Mirov, Sergey

    2017-02-01

    Temperature influence on spectroscopic characteristics is crucial for many aspects of laser engineering including output noise, single frequency oscillation, and thermal bistability. We report on the spectroscopic characterization of chromium and iron doped ZnSe gain element media at temperatures ranging from 77K to 389K. Heating of Cr:ZnSe resulted in the absorption peak shifting to a shorter wavelength from 1.806 μm at 77K to 1.753 μm at 389K. It also resulted in broadening of the absorption band from Δλ=260 cm-1nm to Δλ=373 cm-1nm and decreasing of the absorption cross section by 69%. Similar characterization was done for Fe:ZnSe laser material. The cooling of the Fe:ZnSe crystal from room temperature to 77K resulted in a 32% increase of the absorption coefficient at 2.94 μm which is usually used as a pump source. We also studied the absorption of the electrical free-carriers in n-type Al:ZnSe crystals in visible and mid- IR absorption spectral ranges. Diffusion of Al into ZnSe samples was achieved by annealing at 1000°C during 4 days in Al vapors. It was demonstrated that free-carriers absorption of Al:ZnSe samples with resistivity σ=100-150 Ω×cm resulted in an increase of the absorption coefficient at 2.4 μm up to 2.5 cm-1.

  13. Phase Change Material for Temperature Control of Imager or Sounder on GOES Type Satellites in GEO

    Science.gov (United States)

    Choi, Michael

    2013-01-01

    An imager or sounder on satellites, such as the Geostationary Operational Environmental Satellite (GOES), in geostationary orbit (GEO) has a scan mirror and motor in the scan cavity. The GEO orbit is 24 hours long. During part of the orbit, direct sunlight enters the scan aperture and adds heat to components in the scan cavity. Solar heating also increases the scan motor temperature. Overheating of the scan motor could reduce its reliability. For GOES-N to P, a radiator with a thermal louver rejects the solar heat absorbed to keep the scan cavity cool. A sunshield shields the radiator/louver from the Sun. This innovation uses phase change material (PCM) in the scan cavity to maintain the temperature stability of the scan mirror and motor. When sunlight enters the scan aperture, solar heating causes the PCM to melt. When sunlight stops entering the scan aperture, the PCM releases the thermal energy stored to keep the components in the scan cavity warm. It reduces the heater power required to make up the heat lost by radiation to space through the aperture. This is a major advantage when compared to a radiator/ louver. PCM is compact because it has a high solid-to-liquid enthalpy. Also, it could be spread out in the scan cavity. This is another advantage. Paraffin wax is a good PCM candidate, with high solid-to-liquid enthalpy, which is about 225 kJ/kg. For GOES-N to P, a radiator with a louver rejects the solar heat that enters the aperture to keep the scan cavity cool. For the remainder of the orbit, sunlight does not enter the scan aperture. However, the radiator/louver continues radiating heat to space because the louver effective emittance is about 0.12, even if the louver is fully closed. This requires makeup heater power to maintain the temperature within the stability range.

  14. 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

  15. Strength and Density of Geopolymer Mortar Cured at Ambient Temperature for Use as Repair Material

    Science.gov (United States)

    Warid Wazien, A. Z.; Bakri Abdullah, Mohd Mustafa Al; Abd. Razak, Rafiza; Mohd Remy Rozainy, M. A. Z.; Faheem Mohd Tahir, Muhammad

    2016-06-01

    Geopolymers produced by synthesizing aluminosilicate source materials with an alkaline activator solution promised an excellent properties akin to the existing construction material. This study focused on the effect of various binder to sand ratio on geopolymer mortar properties. Mix design of geopolymer mortar was produced using NaOH concentration of 12 molars, ratio of fly ash/alkaline activator and ratio Na2SiO3/NaOH of 2.0 and 2.5 respectively. Samples subsequently ware cured at ambient temperature. The properties of geopolymer mortar were analysed in term of compressive strength and density at different period which are on the 3rd and 7th day of curing. Experimental results revealed that the addition of sand slightly increase the compressive strength of geopolymer. The optimum compressive strength obtained was up to 31.39 MPa on the 7th day. The density of geopolymer mortar was in the range between 2.0 g/cm3 to 2.23 g/cm3. Based on this findings, the special properties promoted by geopolymer mortar display high potential to be implemented in the field of concrete patch repair.

  16. 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

  17. Circulatory osmotic desalination driven by a mild temperature gradient based on lower critical solution temperature (LCST) phase transition materials.

    Science.gov (United States)

    Mok, Yeongbong; Nakayama, Daichi; Noh, Minwoo; Jang, Sangmok; Kim, Taeho; Lee, Yan

    2013-11-28

    Abrupt changes in effective concentration and osmotic pressure of lower critical solution temperature (LCST) mixtures facilitate the design of a continuous desalination method driven by a mild temperature gradient. We propose a prototype desalination system by circulating LCST mixtures between low and high temperature (low T and high T) units. Water molecules could be drawn from a high-salt solution to the LCST mixture through a semipermeable membrane at a temperature lower than the phase transition temperature, at which the effective osmotic pressure of the LCST mixture is higher than the high-salt solution. After transfer of water to the high T unit where the LCST mixture is phase-separated, the water-rich phase could release the drawn water into a well-diluted solution through the second membrane due to the significant decrease in effective concentration. The solute-rich phase could be recovered in the low T unit via a circulation process. The molar mass, phase transition temperature, and aqueous solubility of the LCST solute could be tuneable for the circulatory osmotic desalination system in which drawing, transfer, release of water, and the separation and recovery of the solutes could proceed simultaneously. Development of a practical desalination system that draws water molecules directly from seawater and produces low-salt water with high purity by mild temperature gradients, possibly induced by sunlight or waste heat, could be attainable by a careful design of the molecular structure and combination of the circulatory desalination systems based on low- and high-molar-mass LCST draw solutes.

  18. Evaluation of mechanical and thermal properties of insulation materials for HTS power devices at liquid nitrogen temperature

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyung Seop; Diaz, Mark Angelo [Dept. of Mechanical Design Engineering, Andong National University, Andong (Korea, Republic of)

    2017-06-15

    In superconducting power devices including power cables in which high temperature superconducting (HTS) tapes are utilized, a reliable electrical insulation should be achieved for its maximum performance. For an efficient design of HTS superconducting devices, a comparative evaluation of the mechanical and thermal propperties for various insulation materials at cryogenic temperatures is required. Especially, in the process of the property evaluation of the sheet-shaped insulation materials, anisotropy according to the machining direction should be considered because the mechanical and thermal properties are significantly influenced by the sample orientation. In this study, the cryogenic thermal and mechanical properties of various insulation material sheets such as PPLP, Cryoflex, Teflon, and Kapton were determined considering sample orientation. All samples tested at cryogenic temperature showed significantly higher tensile strength as compared with that of room temperature. The ultimate tensile strength at both temperature conditions significantly depended upon the sample orientation. The thermal properties of the insulation materials exhibited a slight difference among samples depending on the orientation: for the PPLP and Cryoflex, the CD orientation showed larger thermal contraction up to 77 K as compared to the MD one. MD samples in PPLP and Cryoflex showed a lower CTE and thermal contraction which made it more promising as an insulation material due to its comparable CTE with HTS CC tapes.

  19. Smoothing effect of the thermal interface material on the temperature distribution in a stepwise varying width microchannel cooling device

    Science.gov (United States)

    Riera, Sara; Barrau, Jérôme; Rosell, Joan I.; Fréchette, Luc G.; Omri, Mohamed; Vilarrubí, Montse; Laguna, Gerard

    2017-09-01

    The impact of the thermal interface material (TIM) layer on the performance of a stepwise varying width microchannel cooling device is analysed. A numerical model shows that the TIM layer, besides its well known negative impact on the temperature, also generates a smoothing effect on the temperature distribution. In this study, an analytical model is used to define a nondimensional parameter, called Smoothing Resistance ratio, as the quotient between the origin of the temperature non uniformities and the TIM thermal resistance that flatten the temperature distribution. The relationship between the temperature uniformity of the cooled device, expressed through the temperature standard deviation, and the Smoothing Resistance ratio is shown to be linear. These results lead to the definition of a new design procedure for this kind of cooling device, which aims to reduce the Smoothing Resistance ratio. Two solutions are identified and their drawbacks are analysed.

  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. 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.)

  2. Low-temperature radiation-resistant material for ball-bearing retainers

    Science.gov (United States)

    Desau, P. O.; Emmons, W. F.

    1970-01-01

    Radiation resistant material, made of polyimide polymers and S-glass cloth, is used in ball bearing retainers for extreme environments. Material displays satisfactory wear resistance, lubricity, and stability. Results of comparative tests with fluorocarbon materials are given.

  3. 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.

  4. 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)

  5. 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.

  6. 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.

  7. Austenitic Steels at Low Temperature: Joint International Cryogenic Engineering Conference and International Cryogenic Materials Conference

    CERN Document Server

    Horiuchi, T; ICEC-ICMC

    1983-01-01

    The need for alternate energy sources has led to the develop­ ment of prototype fusion and MHD reactors. Both possible energy systems in current designs usually require the use of magnetic fields for plasma confinement and concentration. For the creation and maintenance of large 5 to 15 tesla magnetic fields, supercon­ ducting magnets appear more economical. But the high magnetic fields create large forces, and the complexities of the conceptual reactors create severe space restrictions. The combination of re­ quirements, plus the desire to keep construction costs at a mini­ mum, has created a need for stronger structural alloys for service at liquid helium temperature (4 K). The complexity of the required structures requires that these alloys be weldable. Furthermore, since the plasma is influenced by magnetic fields and since magnet­ ic forces from the use of ferromagnetic materials in many configur­ ations may be additive, the best structural alloy for most applica­ tions should be nonmagnetic. Thes...

  8. 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.

  9. Effect of temperature on acid hydrolysis of Jerusalem artichoke as raw material for ethanol production

    Directory of Open Access Journals (Sweden)

    Razmovski Radojka N.

    2013-01-01

    Full Text Available Jerusalem artichoke (JA is a low-requirement crop, which does not interfere with food chain, and is a promising carbon source for industrial fermentation. Microbial conversion of such a renewable raw material to useful products, such as ethanol, is an important objective in industrial biotechnology. In this study, ethanol was efficiently produced from the hydrolyzates of JA obtained at different pH values (pH 2.5, pH 3.0 and pH 3.5, temperature (120, 130, 132 and 134°C and hold time (30 and 60 min by Saccharomyces cerevisiae. The efficient degradation of JA by HCl under certain experimental conditions was confirmed by thin-layer chromatography. Ethanol concentration of 7.52% (w/w, which corresponds to 93.89 % of the theoretical yield is achieved by ethanol fermentation of JA hydrolyzate obtained at pH 2.5. [Projekat Ministarstva nauke Republike Srbije, br. TR-31002

  10. Compatibility of strontium-90 fluoride with containment materials at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fullam, H.T.

    1981-08-01

    The use of /sup 90/SrF/sub 2/ as a heat-source fuel requires that the /sup 90/Sr be adequately contained during heat-source service. A program for determining the compatibility of /sup 90/SrF/sub 2/ with containment materials at heat-source operating temperatures is described. These compatibility studies included: initial and supplemental screening tests; WESF /sup 90/SrF/sub 2/ capsule demonstration tests; thermal gradient test; and long-term tests. TZM, Haynes Alloy 25, and Hastelloy C-276 were the three materitals selected for evaluation at 600/sup 0/, 800/sup 0/ and 1000/sup 0/C for periods up to 30,000 h. Results showed that all three alloys suffered substantial attack when exposed to the /sup 90/SrF/sub 2/, although the TZM was more resistant to attack than the Hastelloy C-276 and Haynes Alloy 25. The latter two alloys appeared to provide about equal resistance to fluoride attack for exposures longer than about 12,000 h. Attack of the alloys tested by the /sup 90/SrF/sub 2/ was due primarily to impurities.

  11. 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.

  12. 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.

  13. Experimental study of temperature distribution in rubber material during microwave heating and vulcanization process

    Science.gov (United States)

    Chen, Hai-Long; Li, Tao; Liang, Yun; Sun, Bin; Li, Qing-Ling

    2017-03-01

    Microwave technology has been employed to heat sheet rubber, the optical fiber temperature online monitor and optical fiber temperature sensor have been employed to measure the temperature in sheet rubber. The temperature of sheet rubber increased with increase of heating time during microwave heating process in which the maximum of temperature was vulcanization process in which the maximum of temperature was vulcanization process of sheet rubber, the maximum of rate of temperature rising and the maximum of temperature belong to the central zone of sheet rubber, so the distribution of electric field was uneven in heating chamber, which led to the uneven temperature distribution of sheet rubber. The higher electric field intensity value converges on the central zone of sheet rubber.

  14. Investigation of the effect of temperature, porosity, and microstructure on the strength of meteoric and planetary materials

    Science.gov (United States)

    Chen, Laura; Swift, Damian; Herbold, Eric; Tear, Gareth; Zick, Tom; Brugman, Ben; Remington, Tane; Bruck Syal, Megan; Strang, Eric

    2017-06-01

    Laser-driven shock experiments have been performed at the Trident Laser facility at Los Alamos National Laboratory and at the Janus laser at the Lawrence Livermore National Laboratory, investigating Fe, Fe-Ni metals, silicates, Fe-rich meteorites and chondrites under high strain-rate, dynamic loading at a range of initial temperatures. Material strength as a function of temperature, porosity, and microstructure is studied to reveal the kinetics attributed to the deformation of each material. Post-shock recovery analyses including x-ray diffraction, SEM/EBSD, and x-ray tomography help characterize microstructural and mesoscale changes in the constituent materials. The ultimate goal is to account for varying material and microstructure within meteors subjected to shock wave induced thermal gradients to predict how a bolide will break-up and ablate under high strain-rate loading, such as atmospheric entry, as well as provide reliable models for asteroid deflection methods.

  15. Effect of Temperature on Precipitation Rate of Calcium Carbonate Produced through Microbial Metabolic Process of Bio Materials

    Directory of Open Access Journals (Sweden)

    Prima Yane Putri

    2016-09-01

    Full Text Available Concrete is the most widely used construction material in civil engineering. But plain concrete is a brittle material and has little resistance to cracking. The cracking in concrete promotes deterioration such as the corrosion of reinforcing rebar, therefore, repair in filling the crack is often carried out. Recently, repair methods using bio-based materials associated with microbial metabolic processes leading to precipitation of calcium carbonate have been intensively studied. In this study, influencing factors on the precipitation rate depending on the constituents of bio-based material comprising yeast, glucose and calcium acetate mixed in tris buffer solution was examined for improving the rate of initial reactions. In addition, effect of temperature change on the amount of calcium carbonate precipitation was also investigated. The precipitates were identified by X-ray diffraction. It was shown that the increase of temperature lead to a change on calcium carbonate precipitation and caused the pH decrease under 7.0.

  16. 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.

  17. Collaborative Research. Fundamental Science of Low Temperature Plasma-Biological Material Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Graves, David Barry [Univ. California, Berkeley, CA (United States); Oehrlein, Gottlieb [Univ. of Maryland, College Park, MD (United States)

    2014-09-01

    atmospheric pressure using several types of low temperature plasma sources, for which radical induced interactions generally dominate due to short mean free paths of ions and VUV photons. For these conditions we demonstrated the importance of environmental interactions when atmospheric pressure plasma sources are used to modify biomolecules. This is evident from both gas phase characterization data and in-situ surface characterization of treated biomolecules. Environmental interactions can produce unexpected outcomes due to the complexity of reactions of reactive species with the atmosphere which determines the composition of reactive fluxes and atomistic changes of biomolecules. Overall, this work clarified a richer spectrum of scientific opportunities and challenges for the field of low temperature plasma-biomolecule surface interactions than initially anticipated, in particular for plasma sources operating at atmospheric pressure. The insights produced in this work, e.g. demonstration of the importance of environmental interactions, are generally important for applications of APP to materials modifications. Thus one major contributions of this research has been the establishment of methodologies to more systematically study the interaction of plasma with bio-molecules. In particular, our studies of atmospheric pressure plasma sources using very well-defined experimental conditions enabled to combine atomistic surface modifications of biomolecules with changes in their biological function. The clarification of the role of ions, VUV photons and radicals in deactivation of biomolecules during low pressure and atmospheric pressure plasma-biomolecule interaction has broad implications, e.g. for the emerging field of plasma medicine. The development of methods to detect the effects of plasma treatment on immune-active biomolecules will be helpful in many future studies.

  18. Study of the temperature dependence of the uniaxial creep property of similar material of new soft rock

    Science.gov (United States)

    Wang, Y. Y.; Wu, Y.; Fan, X. Y.; Zhang, J. L.; Guo, P.; Li, J. G.

    2017-11-01

    Using the experimental method, the experimental research of creep properties were conducted under different temperature ranging from 10°C to 60°C. The similar material of new soft rock consists of paraffin, which can obtain that the deformation contains the instantaneous elastic deformation and creep deformation through the uniaxial creep experimental results. And thus the increase of temperature has great influence on the creep characteristics of similar soft rock according to the creep curve of similar soft rock at 10°C to 60°C. With the increase of temperature, the slope of the stress-strain curve of similar soft rock is increasing, while the average of the creep modulus is decreasing, which means that the capacity of resist deformation is reduced. Therefore, the creeps law of high-temperature and short-time can be shown the creep phenomenon of low-temperature and long-time, and further shorten the creep experimental cycle.

  19. Effect of irradiation temperature in PWR RPV materials and its inclusion in semi-mechanistic model

    Energy Technology Data Exchange (ETDEWEB)

    Debarberis, L. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands); Acosta, B. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands)]. E-mail: beatriz.acosta-iborra@jrc.nl; Zeman, A. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands); Sevini, F. [Joint Research Centre of the European Commission, Institute for Energy, P.O. Box 2, 1755 ZG Petten (Netherlands); Ballesteros, A. [Tecnatom, Avd. Montes de Oca 1, San Sebasitan de los Reyes, E-28709 Madrid (Spain); Kryukov, A. [Russian Research Centre Kurchatov Institute, Kurchatov Square 1, 123182 Moscow (Russian Federation); Gillemot, F. [AEKI Atomic Research Institute, Konkoly Thege M. ut 29-33, 1121 Budapest (Hungary); Brumovsky, M. [NRI, Nuclear Research Institute, Husinec, Rez 130, 25068 Rez (Czech Republic)

    2005-09-15

    The irradiation temperature is a very important parameter in radiation damage kinetics. In this article the challenge of including temperature into a general semi-mechanistic model for radiation embrittlement is presented. In this manner the model allows data obtained at different temperatures, both in surveillance programmes and in research reactors, to be understood.

  20. Fabrication and Characterizations of Materials and Components for Intermediate Temperature Fuel Cells and Water Electrolysers

    DEFF Research Database (Denmark)

    Jensen, Annemette Hindhede; Prag, Carsten Brorson; Li, Qingfeng

    and electrolysers for operation in the intermediate temperature range from 200 to 400 °C. The intermediate temperature interval is of importance for the use of renewable fuels. Furthermore electrode kinetics is significantly enhanced compared to when operating at low temperature. Thus non-noble metal catalysts...

  1. Flow behaviour of autoclaved, 20% cold worked, Zr-2.5Nb alloy pressure tube material in the temperature range of room temperature to 800 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Dureja, A.K., E-mail: akdureja@barc.gov.in [Reactor Design and Development Group, Bhabha Atomic Research Centre, Mumbai 85 (India); Sinha, S.K.; Srivastava, Ankit; Sinha, R.K. [Reactor Design and Development Group, Bhabha Atomic Research Centre, Mumbai 85 (India); Chakravartty, J.K. [Materials' Group, Bhabha Atomic Research Centre, Mumbai 85 (India); Seshu, P.; Pawaskar, D.N. [Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai 76 (India)

    2011-05-01

    Pressure tube material of Indian Heavy Water Reactors is 20% cold-worked and stress relieved Zr-2.5Nb alloy. Inherent variability in the process parameters during the fabrication stages of pressure tube and also along the length of component have their effect on micro-structural and texture properties of the material, which in turn affect its strength parameters (yield strength and ultimate tensile strength) and flow characteristics. Data of tensile tests carried out in the temperature range from room temperature to 800 deg. C using the samples taken out from a single pressure tube have been used to develop correlations for characterizing the strength parameters' variation as a function of axial location along length of the tube and the test temperature. Applicability of Ramberg-Osgood, Holloman and Voce's correlations for defining the post yield behaviour of the material has been investigated. Effect of strain rate change on the deformation behaviour has also been studied.

  2. 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)

  3. Effect of Light Activation of Pulp-Capping Materials and Resin Composite on Dentin Deformation and the Pulp Temperature Change.

    Science.gov (United States)

    Soares, C J; Ferreira, M S; Bicalho, A A; de Paula Rodrigues, M; Braga, Ssl; Versluis, A

    2017-10-04

    To analyze the effect of pulp-capping materials and resin composite light activation on strain and temperature development in the pulp and on the interfacial integrity at the pulpal floor/pulp-capping materials in large molar class II cavities. Forty extracted molars received large mesio-occlusal-distal (MOD) cavity bur preparation with 1.0 mm of dentin remaining at the pulp floor. Four pulp-capping materials (self-etching adhesive system, Clearfil SE Bond [CLE], Kuraray), two light-curing calcium hydroxide cements (BioCal [BIO], Biodinâmica, and Ultra-Blend Plus [ULT], Ultradent), and a resin-modified glass ionomer cement- (Vitrebond [VIT], 3M ESPE) were applied on the pulpal floor. The cavities were incrementally restored with resin composite (Filtek Z350 XT, 3M ESPE). Thermocouple (n=10) and strain gauge (n=10) were placed inside the pulp chamber in contact with the top of the pulpal floor to detect temperature changes and dentin strain during light curing of the pulp-capping materials and during resin composite restoration. Exotherm was calculated by subtracting postcure from polymerization temperature (n=10). Interface integrity at the pulpal floor was investigated using micro-CT (SkyScan 1272, Bruker). The degree of cure of capping materials was calculated using the Fourier transform infrared and attenuated total reflectance cell. Data were analyzed using one-way analysis of variance followed by the Tukey test (α=0.05). Pulpal dentin strains (μs) during light curing of CLE were higher than for other pulp-capping materials (pcomposite light activation, the pulpal dentin strain increased for ULT, VIT, and CLE and decreased for BIO. The pulpal dentin strain was significantly higher during pulp-capping light activation. The temperature inside the pulp chamber increased approximately 3.5°C after light curing the pulp-capping materials and approximately 2.1°C after final restoration. Pulp-capping material type had no influence temperature increase. The micro

  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. A temperature oscillation instrument to determine pyroelectric properties of materials at low frequencies : Towards elimination of lock-in methods

    NARCIS (Netherlands)

    Khanbareh, H.; Schelen, J.B.J.; Van der Zwaag, S.; Groen, W.A.

    2015-01-01

    Pyroelectric properties of materials can be accurately determined by applying a new digital signal processing method on the discrete sampled data obtained with a temperature oscillation technique. The pyroelectric coefficient is calculated from the component of the generated current 90? out of phase

  6. 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.

  7. Mesoporous Germanium Anode Materials for Lithium-Ion Battery with Exceptional Cycling Stability in Wide Temperature Range.

    Science.gov (United States)

    Choi, Sinho; Cho, Yoon-Gyo; Kim, Jieun; Choi, Nam-Soon; Song, Hyun-Kon; Wang, Guoxiu; Park, Soojin

    2017-04-01

    Porous structured materials have unique architectures and are promising for lithium-ion batteries to enhance performances. In particular, mesoporous materials have many advantages including a high surface area and large void spaces which can increase reactivity and accessibility of lithium ions. This study reports a synthesis of newly developed mesoporous germanium (Ge) particles prepared by a zincothermic reduction at a mild temperature for high performance lithium-ion batteries which can operate in a wide temperature range. The optimized Ge battery anodes with the mesoporous structure exhibit outstanding electrochemical properties in a wide temperature ranging from -20 to 60 °C. Ge anodes exhibit a stable cycling retention at various temperatures (capacity retention of 99% after 100 cycles at 25 °C, 84% after 300 cycles at 60 °C, and 50% after 50 cycles at -20 °C). Furthermore, full cells consisting of the mesoporous Ge anode and an LiFePO4 cathode show an excellent cyclability at -20 and 25 °C. Mesoporous Ge materials synthesized by the zincothermic reduction can be potentially applied as high performance anode materials for practical lithium-ion batteries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Novel Electrode Materials for Low-Temperature Solid-Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Shaowu Zha; Meilin Liu

    2005-03-23

    Composites electrodes consisting of silver and bismuth vanadates exhibit remarkable catalytic activity for oxygen reduction at 500-550 C and greatly reduce the cathode-electrolyte (doped ceria) resistances of low temperature SOFCs, down to about 0.53 {omega}cm{sup 2} at 500 C and 0.21 {omega}cm{sup 2} at 550 C. The observed power densities of 231, 332, and 443 mWcm-2 at 500, 525 and 550 C, respectively, make it possible to operate SOFCs at temperatures about 500 C. Fuel cell performance depends strongly on the anode microstructure, which is determined by the anode compositions and fabrication conditions. Four types of anodes with two kinds of NiO and GDC powders were investigated. By carefully adjusting the anode microstructure, the GDC electrolyte/anode interfacial polarization resistances reduced dramatically. The interfacial resistance at 600 C decreased from 1.61 {omega} cm{sup 2} for the anodes prepared using commercially available powders to 0.06 {omega} cm{sup 2} for those prepared using powders derived from a glycine-nitrate process. Although steam reforming or partial oxidation is effective in avoiding carbon deposition of hydrocarbon fuels, it increases the operating cost and reduces the energy efficiency. Anode-supported SOFCs with an electrolyte of 20 {micro}m-thick Gd-doped ceria (GDC) were fabricated by co-pressing. A catalyst (1 %wt Pt dispersed on porous Gd-doped ceria) for pre-reforming of propane was developed with relatively low steam to carbon (S/C) ratio ({approx}0.5), coupled with direct utilization of the reformate in low-temperature SOFCs. Propane was converted to smaller molecules during pre-reforming, including H{sub 2}, CH{sub 4}, CO, and CO{sub 2}. A peak power density of 247 mW/cm{sup 2} was observed when pre-reformed propane was directly fed to an SOFC operated at 600 C. No carbon deposition was observed in the fuel cell for a continuous operation of 10 hours at 600 C. The ability of producing vastly different microstructures and

  9. 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.

  10. Sulfate attack of Algerian cement-based material with crushed limestone filler cured at different temperatures

    OpenAIRE

    SENHADJI, Yassine; MOULI, Mohamed; KHELAFI, Hamid

    2010-01-01

    The cement production industry is one of the main consumers of energy and raw materials. Over the last years, a great effort has been made in order to substitute clinker for less energy demanding materials. In many countries, it is popular to use limestone as admixture material to improve the consistency of concrete. Nevertheless, the construction industry needs durable materials with improved properties. Following this objective, this work is a part of an ongoing project developed ...

  11. Temperature-dependent Hall effect measurements on Cz-grown silicon pulled from compensated and recycled feedstock materials

    Science.gov (United States)

    Zhang, Song; Modanese, Chiara; Di Sabatino, Marisa; Tranell, Gabriella

    2015-11-01

    In this work, temperature-dependent Hall effect measurements in the temperature range 88-350 K were carried out to investigate the electrical properties of three solar grade p-type Czochralski (Cz) silicon ingots, pulled from recycled p-type multi-crystalline silicon top cuts and compensated solar grade (SoG) feedstock. Material bulk properties including Hall mobility, carrier density and resistivity as functions of temperature were studied to evaluate the influence of compensation and impurities. Recycled top cut replacing poly-silicon as feedstock leads to a more uniform resistivity. In addition, higher concentrations of O and C, give rise to oxygen related defects, which act as neutral scattering centers displaying only a slight influence on the electrical properties at low temperature compared to the dominant compensation effect. The electrical performances of all samples are shown to be strongly dependent on compensation level, especially at the lowest temperature (~88 K). A significant presence of incompletely ionized phosphorus was deduced through the measured carrier density. The temperature-dependent Hall effect measurements fit Klaassen's mobility model very well at low temperatures (doped silicon, while the deviation at the high temperature probably may be accounted for by the presence of as-grown defects, such as oxygen related defects and phosphorus clusters, which are usually neglected in most mobility models.

  12. Thermal behavior of latent thermal energy storage unit using two phase change materials: Effects of HTF inlet temperature

    Directory of Open Access Journals (Sweden)

    Fouzi Benmoussa

    2017-09-01

    Full Text Available This work presents a numerical study of the thermal behavior of shell-and-tube latent thermal energy storage (LTES unit using two phase change materials (PCMs. The heat transfer fluid (HTF flow through the inner tube and transfer the heat to PCMs. First, a mathematical model is developed based on the enthalpy formulation and solved through the governing equations. Second, the effects of HTF inlet temperature on the unsteady temperature evolution of PCMs, the total energy stored evolution as well as the total melting time is studied. Numerical results show that for all HTF inlet temperature, melting rate of PCM1 is the fastest and that of PCM2 is the slowest; increasing the HTF inlet temperature considerably increases the temperature evolution of PCMs. The maximum energy stored is observed in PCM2 with high melting temperature and high specific heat; heat storage capacity is large for high HTF inlet temperature. When the HTF inlet temperature increases from 338 K to 353 K, decreasing degree of melting time of PCM2 is the biggest from 1870 s to 490 s, which reduces about 73.8%; decreasing degree of melting time of PCM1 is the smallest from 530 s to 270 s, which reduces about 49.1%.

  13. Temperature Effects on the Friction and Wear Behaviors of SiCp/A356 Composite against Semimetallic Materials

    Directory of Open Access Journals (Sweden)

    Like Pan

    2017-01-01

    Full Text Available Due to the low density and high temperature resistance, the SiCp/A356 composites have great potential for weight reduction and braking performance using the brake disc used in trains and automobiles. But the friction coefficient and braking performance are not stable in the braking process because of temperature rising. In this paper, friction and wear behaviors of SiCp/A356 composite against semimetallic materials were investigated in a ring-on-disc configuration in the temperature range of 30°C to 300°C. Experiments were conducted at a constant sliding speed of 1.4 m/s and an applied load of 200 N. Worn surface, subsurface, and wear debris were also examined by using SEM and EDS techniques. The third body films (TBFs lubricated wear transferred to the third body abrasive wear above 200°C, which was a transition temperature. The friction coefficient decreased and weight of semimetallic materials increased with the increase of temperature and the temperature had almost no effect on the weight loss of composites. The dominant wear mechanism of the composites was microploughing and slight adhesion below 200°C, while being controlled by cutting grooves, severe adhesion, and delamination above the 200°C.

  14. Simulation and Experimental Study on Effect of Phase Change Material Thickness to Reduce Temperature of Photovoltaic Panel

    Science.gov (United States)

    Indartono, Y. S.; Prakoso, S. D.; Suwono, A.; Zaini, I. N.; Fernaldi, B.

    2015-09-01

    Solar energy is promising renewable energy which can be applied in Indonesia. Average solar radiation in the country is 4.8 kWh/day/m2. Weakness of silicon-based photovoltaic (PV) is efficiency reduction caused by temperature increase. Many attempts have been done to reduce PV temperature. In previous study, palm oil, which is widely available in Indonesia, is suitable to be used as phase change material (PCM) to reduce PV temperature. In this study, thickness of aluminium rectangular-tube containing phase change material oil is varied. The tube is placed at back part of PV. Numerical and experimental study was done to evaluate the effect of tube thickness to the temperature reduction of the PV. Variation of tube thickness used in the experiment is 50.8mm, 76.2 mm, 101.6 mm. Both studies show that increase of PCM thickness reduces PV temperature. Higher PCM thickness cause large reduction on PV temperature. Simulation result shows there is an optimum thickness of the PCM which is applied to the PV.

  15. Effect of low-temperature conditions on passive layer growth in Li intercalation materials: In situ impedance study

    Energy Technology Data Exchange (ETDEWEB)

    Barsoukov, E.; Kim, J.H.; Kim, J.H.; Yoon, C.O.; Lee, H. [Korea Kumho Petrochemical Co., Taejon (Korea, Republic of). Kumho Chemical Labs.

    1998-08-01

    Electrochemical impedance spectroscopy has been applied to investigate the formation of insulating layers at the surfaces of microscopic particles of mesocarbon microbeads (MCMB), graphite, and hard carbon during the first Li-intercalation into these materials at ambient temperature as well as at {minus}20 C. Investigations were carried out in a three-electrode sandwich cell, designed for impedance measurements in the frequency range 64 kHz to 5 mHz. The impedance spectra, obtained in the potential range 1.5 and 0.02 V during the first charge, were analyzed by complex nonlinear least square fits. A new model, taking into account the porous structure of the intercalation material, electrochemical processes at the interface, as well as spherical diffusion of Li ions toward the centers of the particles, has been used for this analysis. The first intercalation at {minus}20 C results in formation of an insulating layer, which is about 90 times thinner than in the room-temperature case, as concluded from an analysis of experimental results. The irreversible capacity loss, which is 1.3 times larger at {minus}20 C that at room temperature, is ascribed to the formation of a porous precipitate of electrolyte decomposition products on the particle surface. Additional Li intercalation at room temperature results in an irreversible capacity loss of 26% from the initial value, and formation of a composite layer, including low-temperature and room-temperature deposited components.

  16. Material and structural mechanical modelling and reliability of thin-walled bellows at cryogenic temperatures. Application to LHC compensation system

    CERN Document Server

    Garion, Cédric; Skoczen, Blazej

    The present thesis is dedicated to the behaviour of austenitic stainless steels at cryogenic temperatures. The plastic strain induced martensitic transformation and ductile damage are taken into account in an elastic-plastic material modelling. The kinetic law of →’ transformation and the evolution laws of kinematic/isotropic mixed hardening are established. Damage issue is analysed by different ways: mesoscopic isotropic or orthotropic model and a microscopic approach. The material parameters are measured from 316L fine gauge sheet at three levels of temperature: 293 K, 77 K and 4.2 K. The model is applied to thin-walled corrugated shell, used in the LHC interconnections. The influence of the material properties on the stability is studied by a modal analysis. The reliability of the components, defined by the Weibull distribution law, is analysed from fatigue tests. The impact on reliability of geometrical imperfections and thermo-mechanical loads is also analysed.

  17. 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.

  18. 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.

  19. Imbedded fiber optic pressure and temperature sensors enable cure monitoring of pultruded composite materials

    Science.gov (United States)

    Cable, David

    1990-05-01

    The application of fiberoptic multifunction sensing system for the measurement of temperature and pressure during the curing of fiberglass/epoxy composite structure is described. The system employs interferometric principles to measure temperature, pressure, and refractive index of liquids as well as other physical parameters. Fiberoptic pressure and temperature sensors have been employed in monitoring composites pultrusion and molding. The system is ideally suited for monitoring a variety of composite curing processes because of the sensor's microminiature size, tolerance of moderately high temperatures, non-metallic construction, and inherent immunity to electromagnetic and radio frequency signals.

  20. Measurement of sound pressure and temperature in tissue-mimicking material using an optical fiber Bragg grating sensor.

    Science.gov (United States)

    Imade, Keisuke; Kageyama, Takashi; Koyama, Daisuke; Watanabe, Yoshiaki; Nakamura, Kentaro; Akiyama, Iwaki

    2016-10-01

    The experimental investigation of an optical fiber Bragg grating (FBG) sensor for biomedical application is described. The FBG sensor can be used to measure sound pressure and temperature rise simultaneously in biological tissues exposed to ultrasound. The theoretical maximum values that can be measured with the FBG sensor are 73.0 MPa and 30 °C. In this study, measurement of sound pressure up to 5 MPa was performed at an ultrasound frequency of 2 MHz. A maximum temperature change of 6 °C was measured in a tissue-mimicking material. Values yielded by the FBG sensor agreed with those measured using a thermocouple and a hydrophone. Since this sensor is used to monitor the sound pressure and temperature simultaneously, it can also be used for industrial applications, such as ultrasonic cleaning of semiconductors under controlled temperatures.

  1. Interactive effects of temperature, organic carbon, and pipe material on microbiota composition and Legionella pneumophila in hot water plumbing systems.

    Science.gov (United States)

    Proctor, Caitlin R; Dai, Dongjuan; Edwards, Marc A; Pruden, Amy

    2017-10-04

    Several biotic and abiotic factors have been reported to influence the proliferation of microbes, including Legionella pneumophila, in hot water premise plumbing systems, but their combined effects have not been systematically evaluated. Here, we utilize simulated household water heaters to examine the effects of stepwise increases in temperature (32-53 °C), pipe material (copper vs. cross-linked polyethylene (PEX)), and influent assimilable organic carbon (0-700 μg/L) on opportunistic pathogen gene copy numbers and the microbiota composition, as determined by quantitative polymerase chain reaction and 16S rRNA gene amplicon sequencing. Temperature had an overarching influence on both the microbiota composition and L. pneumophila numbers. L. pneumophila peaked at 41 °C in the presence of PEX (1.58 × 10 5 gene copies/mL). At 53 °C, L. pneumophila was not detected. Several operational taxonomic units (OTUs) persisted across all conditions, accounting for 50% of the microbiota composition from 32 to 49 °C and 20% at 53 °C. Pipe material most strongly influenced microbiota composition at lower temperatures, driven by five to six OTUs enriched with each material. Copper pipes supported less L. pneumophila than PEX pipes (mean 2.5 log 10 lower) at temperatures ≤ 41 °C, but showed no difference in total bacterial numbers. Differences between pipe materials diminished with elevated temperature, probably resulting from decreased release of copper ions. At temperatures ≤ 45 °C, influent assimilable organic carbon correlated well with total bacterial numbers, but not with L. pneumophila numbers. At 53 °C, PEX pipes leached organic carbon, reducing the importance of dosed organic carbon. L. pneumophila numbers correlated with a Legionella OTU and a Methylophilus OTU identified by amplicon sequencing. Temperature was the most effective factor for the control of L. pneumophila, while microbiota composition shifted with each stepwise temperature

  2. Ignition criterion for heterogeneous energetic materials based on hotspot size-temperature threshold

    Science.gov (United States)

    Barua, A.; Kim, S.; Horie, Y.; Zhou, M.

    2013-02-01

    A criterion for the ignition of granular explosives (GXs) and polymer-bonded explosives (PBXs) under shock and non-shock loading is developed. The formulation is based on integration of a quantification of the distributions of the sizes and locations of hotspots in loading events using a cohesive finite element method (CFEM) developed recently and the characterization by Tarver et al. [C. M. Tarver et al., "Critical conditions for impact- and shock-induced hot spots in solid explosives," J. Phys. Chem. 100, 5794-5799 (1996)] of the critical size-temperature threshold of hotspots required for chemical ignition of solid explosives. The criterion, along with the CFEM capability to quantify the thermal-mechanical behavior of GXs and PBXs, allows the critical impact velocity for ignition, time to ignition, and critical input energy at ignition to be determined as functions of material composition, microstructure, and loading conditions. The applicability of the relation between the critical input energy (E) and impact velocity of James [H. R. James, "An extension to the critical energy criterion used to predict shock initiation thresholds," Propellants, Explos., Pyrotech. 21, 8-13 (1996)] for shock loading is examined, leading to a modified interpretation, which is sensitive to microstructure and loading condition. As an application, numerical studies are undertaken to evaluate the ignition threshold of granular high melting point eXplosive, octahydro-1,3,5,7-tetranitro-1,2,3,5-tetrazocine (HMX) and HMX/Estane PBX under loading with impact velocities up to 350 ms-1 and strain rates up to 105 s-1. Results show that, for the GX, the time to criticality (tc) is strongly influenced by initial porosity, but is insensitive to grain size. Analyses also lead to a quantification of the differences between the responses of the GXs and PBXs in terms of critical impact velocity for ignition, time to ignition, and critical input energy at ignition. Since the framework permits

  3. 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

  4. 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.

  5. Pengaruh Variasi Temperatur Post Hydrothermal Terhadap Sensitivitas Sensor Gas Co Dari Material Wo3 Hasil Proses Sol Gel

    Directory of Open Access Journals (Sweden)

    Agung Seras Perdana

    2013-03-01

    Full Text Available Gas karbon monoksida (CO adalah gas yang tidak berbau, tidak berwarna, dan tidak larut dalam air, tetapi beracun bila berikatan secara metabolis dengan darah ketika terhirup kedalam tubuh manusia.     Oleh karena itu diperlukan suatu alatberupa sensor untuk mendeteksi keberadaan gas CO secara dini untuk mengindari efek yang berbahaya bagi kesehatan.  Penelitian ini bertujuan mempersiapkan material WO3 sebagai sensor gas CO. Proses sintesa material WO3 dilakukan dengan metode sol gel menggunakan WCl6, ethanol, dan NH4OH. Chip sensor dibuat dari serbuk hasil proses post hydrothermal dengan variasi temperatur 160oC, 180oC dan 200oC selama 12 jam dikompaksi pada tekanan 150 bar dan dianil 300oC selama 1 jam. Proses karakterisasi material WO3 dilakukan dengan pengujian Scanning Electron Microscope (SEM dan X-Ray Diffraction (XRD. Luas permukaan aktif diukur dengan Brauner Emmet Teller (BET, dan pengujian sensitivitas menggunakan alat Potentiostat sebagai Instrumen pengukur arus.     Hasil pengujian menunjukkan struktur kristal adalah monoklinik. Sensitivitas  naik seiring dengan kenaikan temperatur operasi, begitu juga dengan peningkatan konsentrasi gas. Nilai sensitivitas tertinggi adalah pada sampel temperatur 160oC dengan temperatur operasi 100oC dan konsentrasi gas 500 ppm.

  6. Challenges of Handling, Processing, and Studying Liquid and Supercooled Materials at Temperatures above 3000 K with Electrostatic Levitation

    Directory of Open Access Journals (Sweden)

    Takehiko Ishikawa

    2017-10-01

    Full Text Available Over the last 20 years, great progress has been made in techniques for electrostatic levitation, with innovations such as containerless thermophysical property measurements and combination of levitators with synchrotron radiation source and neutron beams, to name but a few. This review focuses on the technological developments necessary for handling materials whose melting temperatures are above 3000 K. Although the original electrostatic levitator designed by Rhim et al. allowed the handling, processing, and study of most metals with melting points below 2500 K, several issues appeared, in addition to the risk of contamination, when metals such as Os, Re, and W were processed. This paper describes the procedures and the innovations that made successful levitation and the study of refractory metals at extreme temperatures (>3000 K possible; namely, sample handling, electrode design (shape and material, levitation initiation, laser heating configuration, and UV range imaging. Typical results are also presented, putting emphasis on the measurements of density, surface tension, and viscosity of refractory materials in their liquid and supercooled phases. The data obtained are exemplified by tungsten, which has the highest melting temperature among metals (and is second only to carbon in the periodic table, rhenium and osmium. The remaining technical difficulties such as temperature measurement and evaporation are discussed.

  7. 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)

  8. 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.

  9. The stress corrosion resistance and the cryogenic temperature mechanical properties of hot rolled Nitronic 32 bar material

    Science.gov (United States)

    Montano, J. W. L.

    1977-01-01

    The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of hot rolled and centerless ground Nitronic 32 stainless steel bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing smooth tensile strength with decreasing temperature to liquid hydrogen temperature. However, below -200 F (-129.0 C) the notched tensile strength decreased slightly and below -320 F (-196.0 C) the decrease was significant. The elongation and reduction of area decreased drastically at temperatures below -200 F (-129.0 C). The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens stressed to 0, 75, and 90 percent of the 0.2 percent yield strength and on transverse 'C'-ring specimens stressed to 75 and 90 percent of the yield strength and exposed to: alternate immersion in a 3.5 percent NaCl bath, humidity cabinet environment, and a 5 percent salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack; however, the 'C'-rings exposed to the alternate immersion and to the salt spray experienced some shallow etching and pitting, respectively. Small cracks appeared in two of the 'C'-rings after one month exposure to the salt spray.

  10. 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.

  11. Pengaruh Variasi pH dan Temperatur Sintering Terhadap Nilai Sensitivitas Material TiO2 Sebagai Sensor Gas CO

    Directory of Open Access Journals (Sweden)

    Ika Silviana Widianti

    2015-03-01

    Full Text Available Telah dilakukan berbagai macam pengupayaan untuk mengoptimalkan potensi Titanium dioksida (TiO2 sebagai sensor gas, mengingat TiO2 merupakan semikonduktor metal oksida. Pada penelitian ini digunakan TiO2 dalam bentuk serbuk, dengan pelarutnya H2SO4 yang diencerkan dengan air distilasi sehingga terbentuk variasi pH 1, 3, dan 5. Metode sol-gel dilakukan dengan perendaman dan dilanjutkan stiring selama 2,5 jam, kecepatan 700 rpm, dan temperatur 200ºC . Drying dilakukan selama 2 jam pada temperatur 350ºC, selanjutnya serbuk dikompaksi pada tekanan 200 bar agar terbentuk pellet. Pelet kemudian disintering pada temperatur 700,800, dan 900ºC selama 1 jam. Karakterisasi material dilakukan dengan Scanning Electron Microscope (SEM dan X-Ray Diffraction (XRD. Sedangkan untuk luas permukaan spesifik sampel TiO2 diuji dengan BET Analyser. Morfologi TiO2 yang dihasilkan dari proses sol-gel berbentuk bulat (spherical dan memiliki fase stabil anatase. Nilai sensitivitas didapatkan dari pengujian pada temperatur operasi 100ºC dan variasi volume gas CO 5L, 12,5L, 25L. Respon tercepat adalah material TiO2 pH 3 yang disinter dengan temperatur 900ºC, serta memiliki ukuran pori 50,83 nm

  12. Magnetic actuator based on giant magnetostrictive material Terfenol-D with strain and temperature monitoring using FBG optical sensor

    OpenAIRE

    García Miquel, Ángel Héctor; Barrera Vilar, David; Amat, Rafael; Kurlyandskaya, G. V.; Sales Maicas, Salvador

    2016-01-01

    We have designed a temperature and strain monitoring system for a magnetic actuator based on the giant magnetostrictive material Terfenol-D (Tb0.3 Dy0.7Fe1.92) with Fiber Bragg grating (FBG) sensors. Magneto-elastic properties of Terfenol-D depend on magnetization, stress pre-history, and temperature. In order to simultaneously monitor these effects, we have implemented a system based on a cylindrical Terfenol-D rod monitored with four FBGs that allows making the appropriate co...

  13. A Simple Method to Estimate the Critical Temperature of Thermal Explosion for Energetic Materials Using Nonisothermal DSC

    Science.gov (United States)

    Xue, L.; Zhao, F. Q.; Hu, R. Z.; Gao, H. X.

    2010-01-01

    A method for estimating critical temperature (T b) of thermal explosion for energetic materials was derived from Semenov's [9] thermal explosion theory and the nonisothermal kinetic equation ? based on Berthelot's expression using reasonable hypotheses. The final formula is ? , which is simple. We can easily obtain the onset temperature (T ei) from the nonisothermal DSC curves, the value of T e0 from the equation ? , the values of b from the equation ? , and then calculate the value of T b. The result obtained with this method coincides completely with the value of T b obtained by Zhang et al.'s [4] method.

  14. Temperature distributions in trapezoidal built in storage solar water heaters with/without phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Tarhan, Sefa; Yardim, M. Hakan [Department of Farm Machinery, Faculty of Agriculture, Gaziosmanpasa University, Tasliciftlik Yerleskesi, 60240 Tokat (Turkey); Sari, Ahmet [Department of Chemistry, Faculty of Arts and Sciences, Gaziosmanpasa University, Tasliciftlik Yerleskesi, 60240 Tokat (Turkey)

    2006-09-15

    Built in storage solar water heaters (BSSWHs) have been recognized for their more compact constructions and faster solar gain than conventional solar water heaters, however, their water temperatures quickly go down during the cooling period. A trapezoidal BSSWH without PCM storage unit was used as the control heater (reference) to investigate the effect of two differently configured PCM storage units on the temperature distributions in water tanks. In the first design, myristic acid was filled into the PCM storage tank, which also served as an absorbing plate. In the second design, lauric acid was filled into the PCM storage tank, which also served as a baffle plate. The water temperature changes were followed by five thermocouples placed evenly and longitudinally into each of the three BSSWHs. The effects of the PCMs on the water temperature distributions depended on the configuration of the PCM storage unit and the longitudinal position in the water tanks. The use of lauric acid lowered the values of the peak temperatures by 15% compared to the control heater at the upper portion of the water tanks because of the low melting temperature of lauric acid, but it did not have any consistent effect on the retention of the water temperatures during the cooling period. The ability of the myristic acid storage unit to retain the water temperatures got more remarkable, especially at the middle portion of the water tank. The myristic acid storage increased the dip temperatures by approximately 8.8% compared to the control heater. In conclusion, lauric acid storage can be used to stabilize the water temperature during the day time, while the myristic acid storage unit can be used as a thermal barrier against heat loss during the night time because of its relatively high melting temperature and low heat conduction coefficient in its solid phase. The experimental results have also indicated that the thermal characteristics of the PCM and the configuration of the PCM storage

  15. 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.

  16. 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.

  17. Low-temperature plasma synthesis of carbon nanotubes and graphene based materials and their fuel cell applications.

    Science.gov (United States)

    Wang, Qi; Wang, Xiangke; Chai, Zhifang; Hu, Wenping

    2013-12-07

    Carbon nanotubes (CNTs) and graphene, and materials based on these, are largely used in multidisciplinary fields. Many techniques have been put forward to synthesize them. Among all kinds of approaches, the low-temperature plasma approach is widely used due to its numerous advantages, such as highly distributed active species, reduced energy requirements, enhanced catalyst activation, shortened operation time and decreased environmental pollution. This tutorial review focuses on the recent development of plasma synthesis of CNTs and graphene based materials and their electrochemical application in fuel cells.

  18. 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.

  19. Development of temperature statistical model when machining of aerospace alloy materials

    OpenAIRE

    Kadirgama Kumaran; Rahman Md. Mustafizur; Mohamed Basir; Bakar Rosli Abu; Ismail Ahmad Rasdan

    2014-01-01

    This paper presents to develop first-order models for predicting the cutting temperature for end-milling operation of Hastelloy C-22HS by using four different coated carbide cutting tools and two different cutting environments. The first-order equations of cutting temperature are developed using the response surface methodology (RSM). The cutting variables are cutting speed, feed rate, and axial depth. The analyses are carried out with the aid of the statis...

  20. Development of temperature statistical model when machining of aerospace alloy materials

    Directory of Open Access Journals (Sweden)

    Kadirgama Kumaran

    2014-01-01

    Full Text Available This paper presents to develop first-order models for predicting the cutting temperature for end-milling operation of Hastelloy C-22HS by using four different coated carbide cutting tools and two different cutting environments. The first-order equations of cutting temperature are developed using the response surface methodology (RSM. The cutting variables are cutting speed, feed rate, and axial depth. The analyses are carried out with the aid of the statistical software package. It can be seen that the model is suitable to predict the longitudinal component of the cutting temperature close to those readings recorded experimentally with a 95% confident level. The results obtained from the predictive models are also compared with results obtained from finite-element analysis (FEA. The developed first-order equations for the cutting temperature revealed that the feed rate is the most crucial factor, followed by axial depth and cutting speed. The PVD coated cutting tools perform better than the CVD-coated cutting tools in terms of cutting temperature. The cutting tools coated with TiAlN perform better compared with other cutting tools during the machining performance of Hastelloy C-22HS. It followed by TiN/TiCN/TiN and CVD coated with TiN/TiCN/Al2O3 and TiN/TiCN/TiN. From the finite-element analysis, the distribution of the cutting temperature can be discussed. High temperature appears in the lower sliding friction zone and at the cutting tip of the cutting tool. Maximum temperature is developed at the rake face some distance away from the tool nose, however, before the chip lift away.

  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. Attenuation of Temperature Fluctuations on an External Surface of the Wall by a Phase Change Material-Activated Layer

    Directory of Open Access Journals (Sweden)

    Dariusz Heim

    2017-12-01

    Full Text Available Periodical changes of temperature on an external surface of building envelope, e.g., thermal stress or excessive heat gains, is often an undesirable phenomenon. The idea proposed and described in the following paper is to stabilize the external surface temperature in a period of significant heat gains by the originally developed, novel composite modified by phase change material (PCM and applied as an external, thin finishing plaster layer. The PCM composite is made from porous, granulated perlite soaked with paraffin wax (Tm = 25 °C and macro-encapsulated by synthetic resin. The effect of temperature attenuation was estimated for two designated periods of time—the heat gains season (HGS and the heat losses season (HLS. The attenuation coefficient (AC was proposed as evaluation parameter of isothermal storage of heat gains determining the reduction of temperature fluctuations. The maximum registered temperature of an external surface for a standard insulation layer was around 20 K higher than for the case modified by PCM. The calculated values of AC were relatively constant during HGS and around two times lower for PCM case. The obtained results confirmed that the proposed modification of an external partition by equipped with additional PCM layer can be effectively used to minimize temperature variations and heat flux in the heat gains season.

  3. An elastic-plastic iceberg material model considering temperature gradient effects and its application to numerical study

    Science.gov (United States)

    Shi, Chu; Hu, Zhiqiang; Luo, Yu

    2016-12-01

    To simulate the FPSO-iceberg collision process more accurately, an elastic-plastic iceberg material model considering temperature gradient effects is proposed and applied. The model behaves linearly elastic until it reaches the `Tsai-Wu' yield surfaces, which are a series of concentric elliptical curves of different sizes. Decreasing temperature results in a large yield surface. Failure criteria, based on the influence of accumulated plastic strain and hydrostatic pressure, are built into the model. Based on published experimental data on the relationship between depth and temperature in icebergs, three typical iceberg temperature profiles are proposed. According to these, ice elements located at different depths have different temperatures. The model is incorporated into LS-DYNA using a user-defined subroutine and applied to a simulation of FPSO collisions with different types of iceberg. Simulated area-pressure curves are compared with design codes to validate the iceberg model. The influence of iceberg shape and temperature on the collision process is analyzed. It is indicated that FPSO structural damage not only depends on the relative strength between the iceberg and the structure, but also depends on the local shape of the iceberg.

  4. 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.

  5. 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.)

  6. Airborne particle emission of a commercial 3D printer: the effect of filament material and printing temperature.

    Science.gov (United States)

    Stabile, L; Scungio, M; Buonanno, G; Arpino, F; Ficco, G

    2017-03-01

    The knowledge of exposure to the airborne particle emitted from three-dimensional (3D) printing activities is becoming a crucial issue due to the relevant spreading of such devices in recent years. To this end, a low-cost desktop 3D printer based on fused deposition modeling (FDM) principle was used. Particle number, alveolar-deposited surface area, and mass concentrations were measured continuously during printing processes to evaluate particle emission rates (ERs) and factors. Particle number distribution measurements were also performed to characterize the size of the emitted particles. Ten different materials and different extrusion temperatures were considered in the survey. Results showed that all the investigated materials emit particles in the ultrafine range (with a mode in the 10-30-nm range), whereas no emission of super-micron particles was detected for all the materials under investigation. The emission was affected strongly by the extrusion temperature. In fact, the ERs increase as the extrusion temperature increases. Emission rates up to 1×10 12  particles min -1 were calculated. Such high ERs were estimated to cause large alveolar surface area dose in workers when 3D activities run. In fact, a 40-min-long 3D printing was found to cause doses up to 200 mm 2 . © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Modeling Temperature Development of Li-ion Battery Packs using Phase Change Materials (PCM) and Fluid Flow

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2014-01-01

    This paper presents a dynamic model for simulating the heat generation and the impact of Phase Change Materials (PCMs) on the maximum temperature in LiFePO4 battery cells. The model is constructed by coupling a one-dimensional electro-chemical model with a two-dimensional thermal model and fluid...... flow model in a battery pack array. Two different physics are analysed and compared, one when the heat equation is considered for the PCM (no-flow case) and another one when fluid flow is considered. The results show that by using PCMs, the maximum temperature drops considerably for both physics....... The temperature differences between the two cases is insignificant, with the observation that by adding fluid flow, the phases mixture is more uniform. Moreover, by using fluid flow, the calculation time increases excessively due to the high non-linearity....

  8. Compilation of erosion yields of metal-doped carbon materials by deuterium impact from ion beam and low temperature plasma

    Energy Technology Data Exchange (ETDEWEB)

    Balden, M., E-mail: Martin.Balden@ipp.mpg.de [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Starke, P. [Lehrstuhl fuer Experimentelle Plasmaphysik, Institut fuer Physik, Universitaet Augsburg, D-86135 Augsburg (Germany); Garcia-Rosales, C. [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain); Adelhelm, C.; Sauter, P.A. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Lopez-Galilea, I.; Ordas, N. [CEIT and Tecnun (University of Navarra), E-20018 San Sebastian (Spain); Fernandez, J.M. Ramos; Escandell, M. Martinez [Departamento de Quimica Inorganica, University of Alicante, E-03690 Alicante (Spain)

    2011-10-01

    The erosion yield by deuterium impact was determined for various doped carbon-based materials. Ion beam bombardment with 30 and 200 eV at elevated temperatures (600-850 K) and low temperature plasma exposure with 30 eV ion energy ({approx}7 x 10{sup 20} ions/m{sup 2}s) and about 170 times higher thermal atomic deuterium flux at 300 K and 630 K were performed. The total yield of fine-grain graphites doped with 4 at.% Ti and Zr is reduced by a factor of 4 for 30 and 200 eV D impact at elevated temperatures at D fluences above 10{sup 24} m{sup -2} compared to undoped graphite. Extensive carbide particle loss can be excluded up to fluences of {approx}10{sup 25} m{sup -2}.

  9. Simulation of the dynamic fracture of ceramic materials based on ZrB2 in a wide temperature range

    Science.gov (United States)

    Fedorov, A. Yu.; Skripnyak, E. G.; Skripnyak, V. V.; Vaganova, I. K.

    2017-12-01

    The damage kinetics and dynamic fracture of nanostructured ZrB2-based ceramics in a wide range of temperatures were studied by the numerical simulation method. 3D models taking into account the distribution of microvoids and inclusions were used for computer simulation of deformation and fracture of ZrB2-based ceramic materials. It was shown that the dynamic fracture of ZrB2-B4C nanocomposites is quasi-brittle in a wide temperature range. The failure is caused by microcrack nucleation and coalescence. The threshold failure stresses for ZrB2-B4C nanocomposites under compression in the strain rate range 10-3-106 s-1 and temperature range from 297 to 1673 K are predicted.

  10. 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.

  11. 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...

  12. Temperature-driven topological quantum phase transitions in a phase-change material Ge2Sb2Te5.

    Science.gov (United States)

    Eremeev, S V; Rusinov, I P; Echenique, P M; Chulkov, E V

    2016-12-13

    The Ge2Sb2Te5 is a phase-change material widely used in optical memory devices and is a leading candidate for next generation non-volatile random access memory devices which are key elements of various electronics and portable systems. Despite the compound is under intense investigation its electronic structure is currently not fully understood. The present work sheds new light on the electronic structure of the Ge2Sb2Te5 crystalline phases. We demonstrate by predicting from first-principles calculations that stable crystal structures of Ge2Sb2Te5 possess different topological quantum phases: a topological insulator phase is realized in low-temperature structure and Weyl semimetal phase is a characteristic of the high-temperature structure. Since the structural phase transitions are caused by the temperature the switching between different topologically non-trivial phases can be driven by variation of the temperature. The obtained results reveal the rich physics of the Ge2Sb2Te5 compound and open previously unexplored possibility for spintronics applications of this material, substantially expanding its application potential.

  13. Temperature control strategy to enhance the activity of yeast inoculated into compost raw material for accelerated composting.

    Science.gov (United States)

    Nakasaki, Kiyohiko; Hirai, Hidehira

    2017-07-01

    The effects of inoculating the mesophilic yeast Pichia kudriavzevii RB1, which is able to degrade organic acids, on organic matter degradation in composting were elucidated. When model food waste with high carbohydrate content (C/N=22.3) was used, fluctuation in the inoculated yeast cell density was observed, as well as fluctuation in the composting temperature until day 5 when the temperature rose to 60°C, which is lethal for the yeast. After the decrease in yeast, acetic acid accumulated to levels as high as 20mg/g-ds in the composting material and vigorous organic matter degradation was inhibited. However, by maintaining the temperature at 40°C for 2days during the heating phase in the early stage of composting, both the organic acids originally contained in the raw material and acetic acid produced during the heating phase were degraded by the yeast. The concentration of acetic acid was kept at a relatively low level (10.1mg/g-ds at the highest), thereby promoting the degradation of organic matter by other microorganisms and accelerating the composting process. These results indicate that temperature control enhances the effects of microbial inoculation into composts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Reusable temperature-sensitive luminescent material based on vitrified film of europium(III) β-diketonate complex

    Science.gov (United States)

    Lapaev, Dmitry V.; Nikiforov, Victor G.; Lobkov, Vladimir S.; Knyazev, Andrey A.; Galyametdinov, Yury G.

    2018-01-01

    We have proposed a novel temperature-sensitive luminescent material which is a 20 μm thick vitrified film (sandwiched between two quartz plates) fabricated from an amorphous powder of a mesogenic europium(III) β-diketonate complex through a melt-processing technique. The film photoexcited by a 337 nm pulsed nitrogen laser displays a typical Eu3+ ion luminescence bands with the strongest peak at 612 nm and with the decay time of 537 μs at 298 K. It is obtained that both the mean luminescence intensity and the luminescence decay time at 612 nm decrease significantly with temperature increasing from 298 to 348 K; the average values of the relative and absolute temperature sensitivities of the luminescence decay time in the range of 298-348 K are -1.2%·K-1 and -6.5 μs·K-1, respectively. The thermal quenching mechanism of the luminescent properties was analyzed and discussed. The experiments showed that, the luminescent properties of the film is insensitive to oxygen, the film is photostable under UV light, there is full reversibility of the temperature-dependent luminescence intensity and the decay time, and the high luminescence brightness of the film can be observed with violet light excitation. These factors indicated that the film is promising material for reusable luminescent thermometers, suitable for long-term monitoring in the range of 298-348 K.

  15. 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.

  16. Effect of microstructure on low temperature electrochemical properties of LiFePO{sub 4}/C cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Nannan; Zhi, Xiaoke; Wang, Li; Liu, Yanhui; Liang, Guangchuan, E-mail: liangguangchuan@hebut.edu.cn

    2015-10-05

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO{sub 4}/C composites was discussed. A conclusion that cathode material is the main limitation for the low temperature performance was come up, by comparing the low temperature performance of 18650 Li-ion batteries with LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} and LiFePO{sub 4}/C as cathode materials. The low temperature performance results indicate the LiFePO{sub 4}/C microstructure is the main factor influencing the low temperature performance of LiFePO{sub 4}. A new LiFePO{sub 4}/C with pomegranate-like spherical structure was proposed in this paper, which shows superior low temperature performance, which can be attributed to its uniform fine primary particles and smaller primary particles. - Highlights: • Low temperature performance of Li-ion battery and LiFePO{sub 4}/C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO{sub 4}/C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO{sub 4}/C has good low temperature performance. - Abstract: The low-temperature electrochemical performance of Li-ion batteries is mainly determined by the choice of cathode material, as evident from a comparison of the low-temperature electrochemical performance of the 18650 batteries with the LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2}, and LiFePO{sub 4}/C as the cathode, respectively, at −20 °C. LiFePO{sub 4}/C materials with different morphologies and microstructures were prepared by different methods. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic charge–discharge measurements and EIS. The low-temperature performance of the samples and those of the coin cells utilizing the materials as cathodes were measured. The results

  17. Deformation behaviour in advanced heat resistant materials during slow strain rate testing at elevated temperature

    Directory of Open Access Journals (Sweden)

    Mattias Calmunger

    2014-01-01

    Full Text Available In this study, slow strain rate tensile testing at elevated temperature is used to evaluate the influence of temperature and strain rate on deformation behaviour in two different austenitic alloys. One austenitic stainless steel (AISI 316L and one nickel-base alloy (Alloy 617 have been investigated. Scanning electron microscopy related techniques as electron channelling contrast imaging and electron backscattering diffraction have been used to study the damage and fracture micromechanisms. For both alloys the dominante damage micromechanisms are slip bands and planar slip interacting with grain bounderies or precipitates causing strain concentrations. The dominante fracture micromechanism when using a slow strain rate at elevated temperature, is microcracks at grain bounderies due to grain boundery embrittlement caused by precipitates. The decrease in strain rate seems to have a small influence on dynamic strain ageing at 650°C.

  18. Optimization of Sour Cherry Juice Spray Drying as
Affected by Carrier Material and Temperature

    Science.gov (United States)

    Zorić, Zoran; Pedisić, Sandra; Dragović-Uzelac, Verica

    2016-01-01

    Summary Response surface methodology was applied for optimization of the sour cherry Marasca juice spray drying process with 20, 30 and 40% of carriers maltodextrin with dextrose equivalent (DE) value of 4–7 and 13–17 and gum arabic, at three drying temperatures: 150, 175 and 200 °C. Increase in carrier mass per volume ratio resulted in lower moisture content and powder hygroscopicity, higher bulk density, solubility and product yield. Higher temperatures decreased the moisture content and bulk density of powders. Temperature of 200 °C and 27% of maltodextrin with 4–7 DE were found to be the most suitable for production of sour cherry Marasca powder. PMID:28115901

  19. Optimization of Sour Cherry Juice Spray Drying as Affected by Carrier Material and Temperature

    Directory of Open Access Journals (Sweden)

    Zoran Zorić

    2016-01-01

    Full Text Available Response surface methodology was applied for optimization of the sour cherry Marasca juice spray drying process with 20, 30 and 40 % of carriers maltodextrin with dextrose equivalent (DE value of 4–7 and 13–17 and gum arabic, at three drying temperatures: 150, 175 and 200 °C. Increase in carrier mass per volume ratio resulted in lower moisture content and powder hygroscopicity, higher bulk density, solubility and product yield. Higher temperatures decreased the moisture content and bulk density of powders. Temperature of 200 °C and 27 % of maltodextrin with 4–7 DE were found to be the most suitable for production of sour cherry Marasca powder.

  20. 3D transient temperature measurement in homogeneous solid material with THz waves

    Science.gov (United States)

    Romano, M.; Sommier, A.; Batsale, J.-C.; Pradere, C.

    2016-04-01

    The first imaging system that is able to measure transient temperature phenomena taking place inside a bulk by 3D tomography is presented. This novel technique combines the power of terahertz waves and the high sensitivity of infrared imaging. The tomography reconstruction is achieved by the 3D motion of the sample at several angular positions followed by inverse Radon transform processing to retrieve the 3D transient temperatures. The aim of this novel volumetric imaging technique is to locate defects within the whole target body as well as to measure the temperature in the whole volume of the target. This new-fashioned thermal tomography will revolutionize the non-invasive monitoring techniques for volume inspection and in-situ properties estimations.

  1. Mechanical properties of friction stir welded 5083 aluminum alloy at cryogenic temperatures : Study on low temperature materials used in WE-NET 20

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, H.; Ishige, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan). Materials Technology Dept.; Hayashi, M.; Oyama, K.; Fujii, H.; Tanaka, J. [Cryogenic Materials Working Group Task 10 (Japan). WE-NET Program

    2002-07-01

    Using hydrogen conversion, the objective of the World Energy Network (WE-NET) program in Japan is the introduction of an international clean energy network, where liquid hydrogen promises to be the most effective carrier and storage medium. The widespread usage of 5083 aluminum alloy in liquid natural gas tankers makes it one of the candidate materials, since it is exposed to cryogenic temperature down to the 111 Kelvin mark. The fracture toughness of the weld metals prepared by conventional large current metal inert-gas (LC-MIG) arc welding was clarified. It was shown to decrease dramatically at temperatures below 77 Kelvin including 20 Kelvin of liquid hydrogen. The microstructure of the weld metals must be refined to achieve an improvement in their fracture toughness. The existence of numerous reports on fine microstructure in welding part of an aluminum alloy with friction stir welding (FSW) makes it a candidate as a possible solution for their usage. In this paper, the authors discussed and reported on the microstructural characteristics and different mechanical properties at cryogenic temperatures of the FSW and the LC-MIG welding. 2 refs., 1 tab., 11 figs.

  2. 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

  3. 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.

  4. 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.

  5. Low-temperature sterilization of wrapped materials using flexible sheet-type dielectric barrier discharge

    Science.gov (United States)

    Eto, Hiroyuki; Ono, Yoshihito; Ogino, Akihisa; Nagatsu, Masaaki

    2008-12-01

    A flexible sheet-type dielectric barrier discharge (DBD) was studied for the low-temperature sterilization of medical instruments wrapped with Tyvek packaging. Sterilization experiments using Geobacillus stearothermophilus spores with a population of 106 were carried out with various mixtures of nitrogen and oxygen. We confirmed the inactivation of spores after 4.5 min of DBD irradiation at a temperature of 28.4 °C and relative humidity of 64.4%. The main sterilizing factors of this method are the ozone and UV emissions generated by DBD in dry air and synergistic OH radicals generated by DBD in moist air.

  6. Effects of temperature, ultraviolet radiation and pectin methyl esterase on aerobic methane release from plant material

    DEFF Research Database (Denmark)

    Bruhn, Dan; Mikkelsen, Teis Nørgaard; Øbro, J.

    2009-01-01

    incubated in glass vials with different combinations of irradiation and/or temperature. Purified dry pectin was incubated in solution, and with or without PME. Before and after incubation, the concentration of CH4 was measured with a gas chromatograph. Rates of CH4 emission were found to depend...... exponentially on temperature and linearly on UV-B irradiance. UV-B had a greater stimulating effect than UV-A, while visible light had no effect on emission rates. PME was found to substantially reduce the potential for aerobic CH4 emissions upon demethylation of pectin....

  7. Effect of temperature and gap opening rate on the resiliency of candidate solid rocket booster O-ring materials

    Science.gov (United States)

    Lach, Cynthia L.

    1992-01-01

    In the redesign of the Space Shuttle solid rocket motor following the Challenger accident, the field and nozzle-to-case joints were designed to minimize gap opening caused by internal motor pressurization during ignition. The O-ring seals and glands for these joints were designed both to accommodate structural deflections and to promote pressure assisted sealing. The resiliency behavior of several candidate O-ring materials was evaluated for the effects of temperature and gap opening rates. The performance of three of the elastomeric materials was tested under the specific redesign gap opening requirement. Dynamic flexure conditions unique to launch produce low frequency vibrations in the gap opening. The effect of these vibrations on the ability of the O-ring to maintain contact with the sealing surface was addressed. The resiliency of the O-ring materials was found to be extremely sensitive to variations in temperature and gap opening rate. The top three elastomeric materials tracked the simulated solid rocket booster (SRB) field joint deflection at 75 and 120 F. The external tank/SRB attach strut load vibrations had a negligible effect on the ability of the O-ring to track the simulated SRB field joint deflection.

  8. Experimental study of discontinuous plastic flow, phase transformation and micro-damage evolution in ductile materials at cryogenic temperatures

    CERN Document Server

    Marcinek, Dawid Jarosław; Sgobba, S

    2009-01-01

    The present Thesis deals with three low temperature phenomena occurring in ductile materials subjected to mechanical loads: serrated yielding, plastic strain induced γ-α’ phase transformation and evolution of micro-damage: - the Thesis explains the physical mechanisms governing each phenomenon at the micro and macroscopic levels; - the document describes in detail the advanced laboratory equipment needed for cryogenic experiments; - the results of tests carried out with unique precision and focused on serrated yielding and evolution of micro-damage (the observations were made with different strain rates and with the use of different materials) are presented; - validation of suitable kinetic laws and identification of parameters for tested materials is carried out.

  9. Design and fabrication of a cryostat for low temperature mechanical testing for the Mechanical and Materials Engineering group at CERN

    Science.gov (United States)

    Aviles Santillana, I.; Betemps, R.; Gerardin, A.; Guinchard, M.; Langeslag, S. A. E.; Sgobba, S.

    2015-12-01

    Mechanical testing of materials at low temperatures is one of the cornerstones of the Mechanical and Materials Engineering (MME) group at CERN. A long tradition of more than 20 years and a unique know - how of such tests has been developed with an 18 kN double-walled cryostat. Large campaigns of material qualification have been carried out and the mechanical behaviour of materials at 4 K has been vastly studied in sub - size samples for projects like LEP, LHC and its experiments. With the aim of assessing the mechanical properties of materials of higher strength and/or issued from heavy gauge products for which testing standardized specimens of larger cross section might be more adapted, a new 100 kN cryostat capable of hosting different shapes of normalized samples has been carefully designed and fabricated inhouse together with the associated tooling and measurement instrumentation. It has been conceived to be able to adapt to different test frames both dynamic and static, which will be of paramount importance for future studies of fracture mechanics at low temperatures. The cryostat features a double-walled vessel consisting of a central cylindrical section with a convex lower end and a flat top end closure. The transmission of the load is guaranteed by a 4 column system and its precise monitoring is assured by an internal load cell positioned next to the sample in the load train. This innovative approach will be discussed together with other nonconventional instrumentation solutions. A validation of the whole system has been carried out, where bending efforts on instrumented samples have been measured. Additionally, dedicated tooling has been fabricated for the device's optimization. The preliminary results obtained confirm an excellent performance of the system and enhance the analysis of materials under extreme conditions with state of the art instrumentation.

  10. Thermochemical Storage of Middle Temperature Wasted Heat by Functionalized C/Mg(OH2 Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Emanuela Mastronardo

    2017-01-01

    Full Text Available For the thermochemical performance implementation of Mg(OH2 as a heat storage medium, several hybrid materials have been investigated. For this study, high-performance hybrid materials have been developed by exploiting the authors’ previous findings. Expanded graphite (EG/carbon nanotubes (CNTs-Mg(OH2 hybrid materials have been prepared through Mg(OH2 deposition-precipitation over functionalized, i.e., oxidized, or un-functionalized EG or CNTs. The heat storage performances of the carbon-based hybrid materials have been investigated through a laboratory-scale experimental simulation of the heat storage/release cycles, carried out by a thermogravimetric apparatus. This study offers a critical evaluation of the thermochemical performances of developed materials through their comparison in terms of heat storage and output capacities per mass and volume unit. It was demonstrated that both EG and CNTs improves the thermochemical performances of the storage medium in terms of reaction rate and conversion with respect to pure Mg(OH2. With functionalized EG/CNTs-Mg(OH2, (i the potential heat storage and output capacities per mass unit of Mg(OH2 have been completely exploited; and (ii higher heat storage and output capacities per volume unit were obtained. That means, for technological applications, as smaller volume at equal stored/released heat.

  11. 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.

  12. Heat Transfer Retardation at Elevated Temperatures. Phase I. Analysis of Heat Transfer Retardation Configurations and Materials.

    Science.gov (United States)

    1983-09-01

    The cenospheres (which are spherical, hollow glass particles) are heated in a mold in air or any inert atmosphere at firing temperatures in the range of...between 2500 to 3000 F, and the cenospheres then shrink together to form a closed-pore ceramic foam. The two problems with the closed-pore foam

  13. Development of a Research Plan to Minimize Thermal Conductivity in Low Temperature Thermoelectric Materials

    Science.gov (United States)

    2010-12-03

    Mechanical refrigeration approaches such as Stirling , reverse Brayton, and Joule-Thomson cycle coolers are frequently used to attain such temperatures {3...with existing mechanical cycles . To become competitive with other cooling technologies, an increase in the thermoelectric figure-of-merit ZT beyond

  14. Effect of Sintering Temperature on the Properties of Aluminium-Aluminium Oxide Composite Materials

    Directory of Open Access Journals (Sweden)

    Dewan Muhammad Nuruzzaman

    2016-12-01

    Full Text Available In this study, aluminium-aluminium oxide (Al-Al2O3 metal matrix composites of different weight percentage reinforcements of aluminium oxide were processed at different sintering temperatures. In order to prepare these composite specimens, conventional powder metallurgy (PM method was used. Three types specimens of different compositions such as 95%Al+5%Al2O3, 90%Al+10%Al2O3 and 85%Al+15%Al2O3 were prepared under 20 Ton compaction load. Then, all the specimens were sintered in a furnace at two different temperatures 550oC and 580oC. In each sintering process, two different heating cycles were used. After the sintering process, it was observed that undistorted flat specimens were successfully prepared for all the compositions. The effects of sintering temperature and weight fraction of aluminium oxide particulates on the density, hardness and microstructure of Al-Al2O3 composites were observed. It was found that density and hardness of the composite specimens were significantly influenced by sintering temperature and percentage aluminium oxide reinforcement. Furthermore, optical microscopy revealed that almost uniform distribution of aluminium oxide reinforcement within the aluminium matrix was achieved.

  15. Temperature-dependent optical properties of Cd(1-x),Zn(x),Te substitute material

    Science.gov (United States)

    Quijada, Manuel A.; Russell, Anne Marie; Hill, Robert J.

    2005-01-01

    In this study, we report cryogenic optical properties of Cd(l-x), Zn(x), Te wafers that are used as substrate seed layers in the manufacturing of HgCdTe focal-plane array detectors. These studies are motivated by the fact that the substrate optical properties influence the overall detector performance. The studies consist of measuring the substrate frequency dependent transmittance T(W) and reflectance R(W) above and below the optical band-gap in the UV/Visible and infrared frequency ranges, and with temperature variation of the sample from 5 to 300 K. Determination of the optical absorption from these measurements show that the optical absorption energy gap near 1.6 eV shows a substantial increase as the temperature is reduced from 300 to 5 K. Furthermore, we observe the presence of infrared-active optical phonons whose peak frequency shifts as the temperature of the sample is varied over the measured temperature range. The theoretical frequency dependent optical conductivity, with allowance for redistribution of spectral weight among the interband transition charge carriers, will be discussed.

  16. Temperature effects on an acoustic emission based SHM system - Applied to composite materials

    NARCIS (Netherlands)

    Vargalui, A.; Martinez, M.J.; Zarouchas, D.; Pant, S.

    2015-01-01

    This study focuses on understanding the effect of temperature variations and the position of the piezoelectric sensors with respect to fiber orientation angle, as it relates to acoustic emission wave velocity in composite structures. A hybrid panel consisting of Unidirectional Carbon Fiber (UDCF)

  17. 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.

  18. Low Temperature Sensing Properties of a Nano Hybrid Material Based on ZnO Nanotetrapods and Titanyl Phthalocyanine

    Directory of Open Access Journals (Sweden)

    Davide Calestani

    2013-03-01

    Full Text Available ZnO nanotetrapods have recently been exploited for the realization of high-sensitivity gas sensors, but they are affected by the typical drawbacks of metal-oxides, i.e., poor selectivity and a relatively high working temperature. On the other hand, it has been also demonstrated that the combined use of nanostructured metal oxides and organic molecules can improve the gas sensing performance sensitivity or selectivity, even at lower temperatures. A gas sensor device, based on films of interconnected ZnO nanotetrapods properly functionalized by titanyl phthalocyanine (TiOPc, has been realized in order to combine the high surface to volume ratio and structural stability of the crystalline ZnO nanostructures with the enhanced sensitivity of the semiconducting TiOPc molecule, especially at low temperature. The electronic properties of the resulting nanohybrid material are different from those of each single component. The response of the hybrid nanostructure towards different gases has been compared with that of ZnO nanotetrapod without functionalization in order to highlight the peculiar properties of the hybrid interaction(s. The dynamic response in time has been studied for different gases and temperatures; in particular, an increase in the response to NO2 has been observed, even at room temperature. The formation of localized p-n heterojunctions and the possibility of exchanging charge carriers at the hybrid interface is shown to be crucial for the sensing mechanism.

  19. Temperature dependent embryonic development of Trichuris suis eggs in a medicinal raw material.

    Science.gov (United States)

    Vejzagić, Nermina; Kringel, Helene; Bruun, Johan Musaeus; Roepstorff, Allan; Thamsborg, Stig Milan; Grossi, Anette Blak; Kapel, Christian M O

    2016-01-15

    The therapeutic potential of infective pig whipworm eggs, Trichuris suis ova (TSO), is currently tested in several clinical trials on immune-mediated diseases. This paper studied the embryonic development of TSO in a medicinal raw product, where the parasite eggs were suspended in sulphuric acid (pH1). Unembryonated T. suis egg batches were stored at 5, 10, 15, 20, 25, 30, and 40°C (±1°C) and examined at 2, 4, 8, and 14 weeks. Subsequently, sub-batches from each temperature were allowed to embryonate for additional 14 weeks at 25°C, and selected samples were tested for infectivity in Göttingen minipigs. Both male and female pigs were used to evaluate eventual gender specific infectivity. Storage at 30°C up to 14 weeks and subsequent embryonation for 14 weeks at 25°C did not significantly reduce the overall larval establishment in minipigs, as compared to storage at 5°C and subsequent embryonation at 25°C. As marked impairment of egg development was observed during storage at 40°C, a second set of unembryonated egg batches were incubated at 30, 32, 34, 36, 38, and 40°C (±1°C) for 1-8 weeks. The development of the eggs was repeatedly examined by manual light microscopy, multispectral analysis (OvaSpec), and an egg hatching assay prior to the final testing in minipigs (Trial 1). These methods showed that the development started earlier at higher temperatures, but the long-term storage at higher temperature affected the egg development. The present study further documents tolerance of the TSO to storage at temperature 5-15°C, at which temperature development of larvae is not initiated. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. 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.

  1. 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.

  2. Creep and Fracture Characteristics of Materials and Structures at Elevated Temperatures

    Science.gov (United States)

    1988-05-01

    Newman [56]. The stress-strain behavior of the employed material was modelled using the Ramberg - Osgood relation. In the case of the power hardening...functions of e and n, cL is the coefficient of the Ramberg Osgood material description, - ’ In a constant given in [181, o-.0 ,e o are the yield stress...SOLVER ’ ABAQUS ’ 28 7 THE J-INTEGRAL 31 7.1 DEFINITION AND PROPERTIES 31 7.2 CALCULATION OF THE J-INTEGRAL VALUE 34 7.3 RESULTS OF THE Jj- AND J2-INTEGRAL

  3. 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.

  4. Simultaneous Strain and Temperature Measurement Using a Single Fiber Bragg Grating Coated with a Thermochromic Material

    Science.gov (United States)

    2017-03-27

    submitted a second journal manuscript; 7) Presented the research results at two conferences (i.e. 2016 ASME SMASIS conference and 2017 SPIE Smart...for the simultaneous measurement of strain and temperature”, the ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems

  5. Temperature induced healing in strained bituminous materials observed by atomic force microscopy

    NARCIS (Netherlands)

    Nahar, S.N.; Schmets, A.J.M.; Scarpas, A.; Schitter, G.

    2013-01-01

    Bitumen is the binder in the composite material named asphalt concrete. Under cyclic mechanical loading of traffic passing over the pavement, eventually damage will initiate in the pavement, leading to eventual structural failure. This damaging process is accelerated by time dependent change of the

  6. 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

  7. 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

  8. 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

  9. 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...

  10. Effect of Temperature, Time, and Material Thickness on the Dehydration Process of Tomato

    Directory of Open Access Journals (Sweden)

    A. F. K. Correia

    2015-01-01

    Full Text Available This study aimed to evaluate the effects of temperature, time, and thickness of tomatoes fruits during adiabatic drying process. Dehydration, a simple and inexpensive process compared to other conservation methods, is widely used in the food industry in order to ensure a long shelf life for the product due to the low water activity. This study aimed to obtain the best processing conditions to avoid losses and keep product quality. Factorial design and surface response methodology were applied to fit predictive mathematical models. In the dehydration of tomatoes through the adiabatic process, temperature, time, and sample thickness, which greatly contribute to the physicochemical and sensory characteristics of the final product, were evaluated. The optimum drying conditions were 60°C with the lowest thickness level and shorter time.

  11. Probing the Subtle Structure Modifications of Thermoelectric Materials by Variable Temperature Total Scattering

    DEFF Research Database (Denmark)

    Reardon, Hazel; Iversen, Bo Brummerstedt; Blichfeld, Anders Bank

    The complex host-guest structure of Type-I inorganic clathrates has been studied fervently within the CMC based on their low thermal conductivity and promising thermoelectric Figure of Merit (zT). We have recently been focused on understanding unusual features in the high temperature diffraction...... data collected over a number of years on Ba8Ga16Ge30 (BGG), where numerous samples have been prepared in-house using various synthesis methods. This led to a comprehensive thermal stability study of clathrate powders, where PXRD revealed amorphous components in the samples treated at high temperature...... in air. PDF measurements were performed on data collected from ex situ annealed BGG samples. This ex situ study (to be submitted), reveals that the seemingly subtle change in the clathrate structure and the emergence of a significant amorphous phase observed from PXRD data is likely to be the result...

  12. 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

  13. 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

  14. 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 ...

  15. Low temperature thermal properties of pentanol-2 — (A perspective polarized target material)

    Science.gov (United States)

    Bunyatova, E. I.; Sahling, A.; Sahling, S.

    1990-07-01

    The low temperature heat capacity and the long-time energy relaxation of pentanol-1 and pentanol-2 were measured. The results demonstrate that pentanol-1 is crystalline and pentanol-2 is amorphous after cooling with a cooling rate of about 1 K min -1. From the power release data of pentanol-2 the distribution parameter of two-level systems P = 4.1 × 10 44J m -3 was obtained.

  16. Organic particulate material levels in the atmosphere: conditions favoring sensitivity to varying relative humidity and temperature.

    Science.gov (United States)

    Pankow, James F

    2010-04-13

    This study examines the sensitivity in predicted levels of atmospheric organic particulate matter (M(o), microg m(-3)) as those levels may potentially be affected by changes in relative humidity and temperature. In a given system, for each partitioning compound, f(g) and f(p) represent the gaseous and particulate fractions (f(g) + f(p) = 1). Sensitivity in the M(o) levels becomes dampened as the compounds contributing significantly to M(o) are increasingly found in the particle phase (f(p) --> 1). Thus, although local maxima in sensitivity can be encountered as M(o) levels increase, because as M(o) increases each f(p) --> 1, then increasing M(o) levels generally tend to reduce sensitivity in M(o) levels to changes in relative humidity and temperature. Experiments designed to elucidate the potential magnitudes of the effects of relative humidity and temperature on M(o) levels must be carried out at M(o) levels that are relevant for the ambient atmosphere: The f(p) values for the important partitioning compounds must not be elevated above ambient-relevant values. Systems in which M(o) levels are low (e.g., 1-2 microg m(-3)) and/or composed of unaged secondary organic aerosol are the ones most likely to show sensitivity to changing relative humidity and temperature. Results from two published chamber studies are examined in the above regard: [Warren B, et al. (2009) Atmos Environ 43:1789-1795] and [Prisle NL, et al. (2010) Geophys Res Lett 37:L01802].

  17. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Versatile variable temperature and magnetic field scanning probe microscope for advanced material research

    Science.gov (United States)

    Jung, Jin-Oh; Choi, Seokhwan; Lee, Yeonghoon; Kim, Jinwoo; Son, Donghyeon; Lee, Jhinhwan

    2017-10-01

    We have built a variable temperature scanning probe microscope (SPM) that covers 4.6 K-180 K and up to 7 T whose SPM head fits in a 52 mm bore magnet. It features a temperature-controlled sample stage thermally well isolated from the SPM body in good thermal contact with the liquid helium bath. It has a 7-sample-holder storage carousel at liquid helium temperature for systematic studies using multiple samples and field emission targets intended for spin-polarized spectroscopic-imaging scanning tunneling microscopy (STM) study on samples with various compositions and doping conditions. The system is equipped with a UHV sample preparation chamber and mounted on a two-stage vibration isolation system made of a heavy concrete block and a granite table on pneumatic vibration isolators. A quartz resonator (qPlus)-based non-contact atomic force microscope (AFM) sensor is used for simultaneous STM/AFM operation for research on samples with highly insulating properties such as strongly underdoped cuprates and strongly correlated electron systems.

  19. Design and fabrication of a cryostat for low temperature mechanical testing for the Mechanical and Materials Engineering group at CERN

    CERN Document Server

    Aviles Santillana, I; Gerardin, A; Guinchard, M; Langeslag, S A E; Sgobba, S

    2015-01-01

    Mechanical testing of materials at low temperatures is one of the cornerstones of the Mechanical and Materials Engineering (MME) group at CERN. A long tradition of more than 20 years and a unique know - how of such tests has been developed with an 18 kN double-walled cryostat. Large campaigns of material qualification have been carried out and the mechanical behaviour of materials at 4 K has been vastly studied in sub - size samples for projects like LEP, LHC and its experiments. With the aim of assessing the mechanical properties of materials of higher strength and/or issued from heavy gauge products for which testing standardized specimens of larger cross section might be more adapted, a new 100 kN cryostat capable of hosting different shapes of normalized samples has been carefully designed and fabricated inhouse together with the associated tooling and measurement instrumentation. It has been conceived to be able to adapt to different test frames both dynamic and static, which will be of paramount importa...

  20. Temperature Effects on a-IGZO Thin Film Transistors Using HfO2 Gate Dielectric Material

    Directory of Open Access Journals (Sweden)

    Yu-Hsien Lin

    2014-01-01

    Full Text Available This study investigated the temperature effect on amorphous indium gallium zinc oxide (a-IGZO thin film transistors (TFTs using hafnium oxide (HfO2 gate dielectric material. HfO2 is an attractive candidate as a high-κ dielectric material for gate oxide because it has great potential to exhibit superior electrical properties with a high drive current. In the process of integrating the gate dielectric and IGZO thin film, postannealing treatment is an essential process for completing the chemical reaction of the IGZO thin film and enhancing the gate oxide quality to adjust the electrical characteristics of the TFTs. However, the hafnium atom diffused the IGZO thin film, causing interface roughness because of the stability of the HfO2 dielectric thin film during high-temperature annealing. In this study, the annealing temperature was optimized at 200°C for a HfO2 gate dielectric TFT exhibiting high mobility, a high ION/IOFF ratio, low IOFF current, and excellent subthreshold swing (SS.

  1. Sensitivity to temperature and material properties of hydrogen concentration at a crack tip in austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Schembri, Philip E [Los Alamos National Laboratory

    2008-01-01

    It is well known that dissolved hydrogen interacts with the stress field at a crack tip, with one result being an intensification of the hydrogen concentration in the region of maximum crack tip stress. The current paper presents recent calculations in ongoing efforts to use coupled stress-diffusion finite element analyses to aid in the structural integrity assessment of pressure vessels containing tritium. The focus of the current work is quantification of the effect of material properties (structural and diffusion) and temperature on the values of maximum stress and hydrogen concentration at the tip of a crack. A one-way-coupled finite element model of a compact tension specimen is used in which the effect of stress and trapping on the hydrogen diffusion is accounted for. Results show that, within the ranges of inputs considered, maximum stress varies approximately linearly with a material's room temperature yield stress but nonlinearly with temperature. Also, peak lattice hydrogen is shown to be a strong function of solubility parameters, a moderate function of yield stress, but only a weak function of trap binding energy and density when trap density is relatively low.

  2. 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.

  3. 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.

  4. Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials

    Science.gov (United States)

    Kwon, Min Sang; Yu, Youngchang; Coburn, Caleb; Phillips, Andrew W.; Chung, Kyeongwoon; Shanker, Apoorv; Jung, Jaehun; Kim, Gunho; Pipe, Kevin; Forrest, Stephen R.; Youk, Ji Ho; Gierschner, Johannes; Kim, Jinsang

    2015-12-01

    Metal-free organic phosphorescent materials are attractive alternatives to the predominantly used organometallic phosphors but are generally dimmer and are relatively rare, as, without heavy-metal atoms, spin-orbit coupling is less efficient and phosphorescence usually cannot compete with radiationless relaxation processes. Here we present a general design rule and a method to effectively reduce radiationless transitions and hence greatly enhance phosphorescence efficiency of metal-free organic materials in a variety of amorphous polymer matrices, based on the restriction of molecular motions in the proximity of embedded phosphors. Covalent cross-linking between phosphors and polymer matrices via Diels-Alder click chemistry is devised as a method. A sharp increase in phosphorescence quantum efficiency is observed in a variety of polymer matrices with this method, which is ca. two to five times higher than that of phosphor-doped polymer systems having no such covalent linkage.

  5. 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...

  6. 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

  7. Effect of austempering temperature on cavitation behaviour of unalloyed ADI material

    Energy Technology Data Exchange (ETDEWEB)

    Dojcinovic, Marina [University of Belgrade, Faculty of Technology and Metallurgy, Karnegijeva 4, Belgrade (Serbia); Eric, Olivera [Innovation Centre, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, Belgrade (Serbia); Rajnovic, Dragan; Sidjanin, Leposava [Department of Production Engineering, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, Novi Sad (Serbia); Balos, Sebastian, E-mail: sebab@uns.ac.rs [Department of Production Engineering, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovića 6, Novi Sad (Serbia)

    2013-08-15

    This paper provides an in-depth study and description of cavitation damage and microstructural changes in two types of unalloyed austempered ductile iron (ADI). ADI materials used were austempered at 300 and 400 °C having ausferrite microstructure with 16 and 31.4% of retained austenite, respectively. Metallographic examination was carried out to study the morphology of their cavitation-damaged surfaces. Cavitation damage was initiated at graphite nodules as well as in the interface between a graphite nodule and an ausferrite matrix. Furthermore, microcracking and ferrite/retained austenite morphology were proved to be of great importance for cavitation resistance. Mass loss rate revealed that ADI austempered at 400 °C has a higher cavitation resistance in water than ADI austempered at 300 °C. A higher amount of retained austenite in ADI austempered at 400 °C played an important role in increasing cavitation resistance. The good cavitation behaviour of ADI austempered at 400 °C was due to the matrix hardening by stress assisted phase transformation of retained austenite into martensite (SATRAM) phenomenon, as shown by X-ray diffraction analysis. - Highlights: • Cavitation rate of two ADI materials was tested. • ADI material with a lower hardness has had a lower cavitation rate. • The main reason is microstructural transformations during cavitation. • SATRAM phenomenon increases cavitation resistance.

  8. Curie Temperature and Microstructural Changes Due to the Heating Treatment of Magnetic Amorphous Materials

    Directory of Open Access Journals (Sweden)

    Gondro J.

    2016-03-01

    Full Text Available Three distinct alloys: Fe86Zr7Nb1Cu1B5, Fe82Zr7Nb2Cu1B8, and Fe81Pt5Zr7Nb1Cu1B5 were characterized both magnetically and structurally. The samples, obtained with spinning roller method as a ribbons 3 mm in width and 20 μm thick, were investigated as-quenched and after each step of a multi steps heating treatment procedure. Each sample was annealed at four steps, fifteen minutes at every temperature, starting from 573K+600K up to +700K depending on type of alloy. Mössbauer spectroscopy data and transmission electron microscope (HRE M pictures confirmed that the as-quenched samples are fully amorphous. This is not changed after the first stages of treatment heating leads to a reduction of free volumes. The heating treatment has a great influence on the magnetic susceptibilities. The treatment up to 600K improves soft magnetic properties: an χ increase was observed, from about 400 to almost 1000 for the samples of alloys without Pt, and from about 200 to 450 at maximum, for the Fe81Pt5Zr7Nb1Cu1B5. Further heating, at more elevated temperatures, leads to magnetic hardening of the samples. Curie temperatures, established from the location of Hopkinson’s maxima on the χ(T curve are in very good agreement with those obtained from the data of specific magnetization, σ(T, measured in a field of 0.75T. As a critical parameter β was chosen to be equal 0.36 for these calculations, it confirmed that the alloys may be considered as ferromagnetic of Heisenberg type. Heating treatment resulted in decreasing of TC. These changes are within a range of several K.

  9. 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.

  10. Theoretical analytical model of vacancy formation energy with simultaneous dependence on surface orientation, temperature, and material size

    Science.gov (United States)

    Zhang, Xuyao; Li, Weiguo; Deng, Yong; Shao, Jiaxing; Kou, Haibo; Ma, Jianzuo; Zhang, Xianhe; Li, Ying

    2018-02-01

    From the perspectives of bond energy theory, the bond–order–length–strength correlation mechanism, and the core–surface configuration for nanomaterials, a physics-based model, free of any adjustable parameters and simultaneously considering the coupling effects of surface orientation, temperature, and size on the vacancy formation energy of metal materials is developed. To confirm our present model, the temperature-dependent vacancy formation energies of six face-centered cubic metals and the size-dependent vacancy formation energies of gold particles are predicted, which are in reasonable agreement with the simulation results. In particular, the model can provide a convenient method to predict the temperature-dependent vacancy formation energy of nanomaterials with different surface orientations, and also can provide a new method to study the structural relaxation. The study shows that the size effect on the vacancy formation energy depends on the stronger bond energy in the surface layers compared with those in the core interior, and the temperature-dependent vacancy formation energy arises from cohesive energy weakening, with the opposite trend to that induced by size reduction.

  11. Nano-Scale Au Supported on Carbon Materials for the Low Temperature Water Gas Shift (WGS Reaction

    Directory of Open Access Journals (Sweden)

    Paula Sánchez

    2011-12-01

    Full Text Available Au-based catalysts supported on carbon materials with different structures such as graphite (G and fishbone type carbon nanofibers (CNF-F were prepared using two different methods (impregnation and gold-sol to be tested in the water gas shift (WGS reaction. Atomic absorption spectrometry, transmission electron microscopy (TEM, temperature-programmed oxidation (TPO, X-ray diffraction (XRD, Raman spectroscopy, elemental analyses (CNH, N2 adsorption-desorption analysis, temperature-programmed reduction (TPR and temperature-programmed decomposition were employed to characterize both the supports and catalysts. Both the crystalline nature of the carbon supports and the method of gold incorporation had a strong influence on the way in which Au particles were deposited on the carbon surface. The higher crystallinity and the smaller and well dispersed Au particle size were, the higher activity of the catalysts in the WGS reaction was noted. Finally, catalytic activity showed an important dependence on the reaction temperature and steam-to-CO molar ratio.

  12. Direct Evidence for Solid-like Hydrogen in a Nanoporous Carbon Hydrogen Storage Material at Supercritical Temperatures.

    Science.gov (United States)

    Ting, Valeska P; Ramirez-Cuesta, Anibal J; Bimbo, Nuno; Sharpe, Jessica E; Noguera-Diaz, Antonio; Presser, Volker; Rudic, Svemir; Mays, Timothy J

    2015-08-25

    Here we report direct physical evidence that confinement of molecular hydrogen (H2) in an optimized nanoporous carbon results in accumulation of hydrogen with characteristics commensurate with solid H2 at temperatures up to 67 K above the liquid-vapor critical temperature of bulk H2. This extreme densification is attributed to confinement of H2 molecules in the optimally sized micropores, and occurs at pressures as low as 0.02 MPa. The quantities of contained, solid-like H2 increased with pressure and were directly evaluated using in situ inelastic neutron scattering and confirmed by analysis of gas sorption isotherms. The demonstration of the existence of solid-like H2 challenges the existing assumption that supercritical hydrogen confined in nanopores has an upper limit of liquid H2 density. Thus, this insight offers opportunities for the development of more accurate models for the evaluation and design of nanoporous materials for high capacity adsorptive hydrogen storage.

  13. Crystalline maricite NaFePO4 as a positive electrode material for sodium secondary batteries operating at intermediate temperature

    Science.gov (United States)

    Hwang, Jinkwang; Matsumoto, Kazuhiko; Orikasa, Yuki; Katayama, Misaki; Inada, Yasuhiro; Nohira, Toshiyuki; Hagiwara, Rika

    2018-02-01

    Maricite NaFePO4 (m-NaFePO4) was investigated as a positive electrode material for intermediate-temperature operation of sodium secondary batteries using ionic liquid electrolytes. Powdered m-NaFePO4 was prepared by a conventional solid-state method at 873 K and subsequently fabricated in two different conditions; one is ball-milled in acetone and the other is re-calcined at 873 K after the ball-milling. Electrochemical properties of the electrodes prepared with the as-synthesized m-NaFePO4, the ball-milled m-NaFePO4, and the re-calcined m-NaFePO4 were investigated in Na[FSA]-[C2C1im][FSA] (C2C1im+ = 1-ethyl-3-methylimidazolium, FSA- = bis(fluorosulfonyl)amide) ionic liquid electrolytes at 298 K and 363 K to assess the effects of temperature and particle size on their electrochemical properties. A reversible charge-discharge capacity of 107 mAh g-1 was achieved with a coulombic efficiency >98% from the 2nd cycle using the ball-milled m-NaFePO4 electrode at a C-rate of 0.1 C and 363 K. Electrochemical impedance spectroscopy using m-NaFePO4/m-NaFePO4 symmetric cells indicated that inactive m-NaFePO4 becomes an active material through ball-milling treatment and elevation of operating temperature. X-ray diffraction analysis of crystalline m-NaFePO4 confirmed the lattice contraction and expansion upon charging and discharging, respectively. These results indicate that the desodiation-sodiation process in m-NaFePO4 is reversible in the intermediate-temperature range.

  14. Studies of low temperature, low flux radiation embrittlement of nuclear reactor structural materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G.R.; Lucas, G.E.

    1998-09-02

    A large matrix of simple alloys and complex commercial type steels was irradiated over a range of fluxes at 60 C up to a fast fluence of about 3 {times} 10{sup 22} n/m{sup 2}. Combined with data in the literature, these results show a negligible effect of flux on irradiation hardening in the range of 2 {times} 10{sup 13} to 5 {times} 10{sup 18} n/m{sup 2}-s. This observation lends indirect support to the proposal that the accelerated embrittlement in the High Flux Isotope Reactor surveillance steels was due to an anomalously high level of damage from gamma rays. A weak dependence of hardening on a number of elements, including copper, nickel, phosphorus, molybdenum and manganese, can be described by a simple empirical chemistry factor. Particular combinations of elements resulted in hardening differences of up to about 60% in the complex commercial type steels and up to about 100% in simple model alloys. Direct effects of microstructure appear to be minimal. Hardening varies with the square root of fluence above a threshold around 4 {times} 10{sup 20} n/m{sup 2}. The results suggest that low temperature hardening is dominated by local intracascade processes leading to the formation of small defect-solute clusters/complexes. The observed hardening corresponds to nominal maximum end-of-life transition temperature shifts in support structure steels of about 120 C.

  15. Bonding III-V material to SOI with transparent and conductive ZnO film at low temperature.

    Science.gov (United States)

    Huang, Xinnan; Gao, Yonghao; Xu, Xingsheng

    2014-06-16

    A procedure of bonding III-V material to SOI at low temperature using conductive and transparent adhesive ZnO as intermediate layer is demonstrated. Bonding layer thickness of less than 100 nm was achieved in our experiment that guaranteed good light coupling efficiency between III-V and silicon. This bonding method showed good bonding strength with shear stress of 80 N/cm(2). The lowest resistance of the bonded samples was 48.9 Ω and the transmittance of the spin-coated ZnO layer was above 99%. This procedure is applicable for fabricating hybrid III-V/Si lasers.

  16. 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)

  17. Magnetic materials at finite temperatures: thermodynamics and combined spin and molecular dynamics derived from first principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Eisenbach, Markus [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perera, Meewanage Dilina N. [Univ. of Georgia, Athens, GA (United States). Center for Simulational Physics; Landau, David P [Univ. of Georgia, Athens, GA (United States). Center for Simulational Physics; Nicholson, Don M. [Univ. of North Carolina, Asheville, NC (United States). Dept. of Physics; Yin, Junqi [Univ. of Tennessee, Knoxville, TN (United States). National Inst. for Computational Sciences; Brown, Greg [Florida State Univ., Tallahassee, FL (United States). Dept. of Physics

    2015-01-01

    We present a unified approach to describe the combined behavior of the atomic and magnetic degrees of freedom in magnetic materials. Using Monte Carlo simulations directly combined with first principles the Curie temperature can be obtained ab initio in good agreement with experimental values. The large scale constrained first principles calculations have been used to construct effective potentials for both the atomic and magnetic degrees of freedom that allow the unified study of influence of phonon-magnon coupling on the thermodynamics and dynamics of magnetic systems. The MC calculations predict the specific heat of iron in near perfect agreement with experimental results from 300K to above Tc and allow the identification of the importance of the magnon-phonon interaction at the phase-transition. Further Molecular Dynamics and Spin Dynamics calculations elucidate the dynamics of this coupling and open the potential for quantitative and predictive descriptions of dynamic structure factors in magnetic materials using first principles-derived simulations.

  18. Nickel and its alloys as perspective materials for intermediate temperature steam electrolysers operating on proton conducting solid acids as electrolyte

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Jensen, Jens Oluf

    2012-01-01

    Several stainless steels, nickel-based alloys, Ta-coated stainless steel, niobium, nickel, platinum and gold were evaluated as possible materials for use in the intermediate temperature water electrolysers. The corrosion resistance was measured in molten KH2PO4 as simulated conditions corresponding...... plates and cell housing. It was shown, that nickel, high-nickel alloys and austenitic stainless steels containing small amounts of Ti have high corrosion resistance in this media. © The Electrochemical Society....... to protonconducting solid acids or transition metal phosphates as electrolytes. It was shown that Au is subject to corrosion in molten KH 2PO4 during polarisation. However, Ni and Ta-coated stainless steel (AISI 316L) demonstrated high corrosion stability and can be recommended as a construction material for bipolar...

  19. Influence of frost damage and sample preconditioning on the porosity characterization of cement based materials using low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Fridh, Katja; Johannesson, Björn

    2015-01-01

    Low temperature calorimetry (LTC) can be used to study the meso-porosity of cement based materials. The influence of frost damage on the meso-porosity determination by LTC was explored on a model material MCM-41 and two cement pastes by conducting repeated cycles of freezing and melting...... the preconditioning has limited influence on the freezing and melting behavior of the pore solution in the studied cement paste samples....... measurements. The results indicate that the pressure generated during freezing and melting measurements has little impact on the pore structure of the powder MCM-41 samples. As for the studied cylinder samples of cement pastes, frost damage probably took place and it changed the pore connectivity while it had...

  20. Electrochemical behavior of the graphene materials synthesized using low temperature plasma

    Science.gov (United States)

    Shavelkina, M. B.; Amirov, R. H.; Richagov, A. Y.; Shatalova, T. B.

    2017-01-01

    By means of DC plasma torch of up to 45 kW power, few-layered graphene sheets were obtained. Their properties and structure were characterized by using electron microscopy, thermal analysis, Raman and infrared (IR) spectroscopy. Boundary surface of samples have been investigated using the method of “limited evaporation” and BET method. Electrochemical examination of their properties was conducted. Due to the activity and stability of synthesized materials the conclusion was made regarding the possibility of the use of them as catalysts carriers for fuel cells electrodes, electric current sources, conducting additives for electrodes in non-aqueous electrolytes.

  1. 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.

  2. Strain-rate and temperature dependent material properties of Agar and Gellan Gum used in biomedical applications.

    Science.gov (United States)

    Schiavi, Alessandro; Cuccaro, Rugiada; Troia, Adriano

    2016-01-01

    Agar and Gellan Gum are biocompatible polymers extensively used in several fields of tissue engineering research (e.g. tissue replacement, tissue support, tissue mimicking), due to their mechanical behaviour effectively representative of actual biological tissues. Since mechanical properties of artificial tissues are related to biocompatibility and functionality of medical implants and significantly influence adhesion, growth and differentiation of cells in tissue-engineering scaffolds, an accurate characterization of Young׳s modulus and relaxation time processes is needed. In this study, the strain-rate and temperature dependent material properties of Agarose and one among the numerous kind of Gellan Gum commercially available, known as Phytagel(®), have been investigated. Nine hydrogel samples have been realized with different mechanical properties: the first one Agar-based as a reference material, the further eight samples Gellan Gum based in which the effect of dispersed solid particles like kieselguhr and SiC, as enhancing mechanical properties factors, have been investigated as a function of concentration. Stress-strain has been investigated in compression and relaxation time has been evaluated by means of the Kohlrausch-Williams-Watts time decay function. Mechanical properties have been measured as a function of temperature between 20 °C and 35 °C and at different strain rates, from ~10(-3)s(-1) and ~10(-2)s(-1) (or deformation rate from ~0.01 mms(-1) to ~0.1 mms(-1)). From experimental data, the combined temperature and strain-rate dependence of hydrogels Young׳s modulus is determined on the basis of a constitutive model. In addition to a dependence of Young׳s modulus on temperature, a remarkable influence of strain-rate has been observed, especially in the sample containing solid particles; in same ranges of temperature and strain-rate, also relaxation time variations have been monitored in order to identify a possible dependence of damping

  3. 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.

  4. 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

  5. Material characterisation and preliminary mechanical design for the HL-LHC shielded beam screens operating at cryogenic temperatures

    CERN Document Server

    Garion, C; Koettig, T; Machiocha, W; Morrone, M

    2015-01-01

    The High Luminosity LHC project (HL-LHC) aims at increasing the luminosity (rate of collisions) in the Large Hadron Collider (LHC) experiments by a factor of 10 beyond the original design value (from 300 to 3000 fb-1). It relies on new superconducting magnets, installed close to the interaction points, equipped with new beam screen. This component has to ensure the vacuum performance together with shielding the cold mass from physics debris and screening the cold bore cryogenic system from beam induced heating. The beam screen operates in the range 40-60 K whereas the magnet cold bore temperature is 1.9 K. A tungsten-based material is used to absorb the energy of particles. In this paper, measurements of the mechanical and physical properties of such tungsten material are shown at room and cryogenic temperature. In addition, the design and the thermal mechanical behaviour of the beam screen assembly are presented also. They include the heat transfer from the tungsten absorbers to the cooling pipes and the sup...

  6. [Determination of normal temperature properties of refractory die material compatible with slip casting core of sintered titanium powder].

    Science.gov (United States)

    Kuang, X; Liao, Y; Chao, Y; Wang, H

    1999-05-01

    The refractory die is the precondition for developing slip casting core of sintered powder. This study is to determine the normal temperature properties of the refractory die material compatible with slip casting core. to mix the die material at five different ratios (8/1, 7.5/1, 7/1, 6.5/1, and 6/1) and measure their solidification time with self-manufactured Vicker's needle; to prepare five cylindrical specimens (phi 10 x 15 mm) in different drying time for determining their compressive strength, and then to let another five specimens fire at 1000 degrees C four times for measuring the residual compressive strength at room temperature. The setting time was 16.25 minutes (7.5/1), and the lower the powder-liquid ratio, the longer the setting time. The normal compressive strength was 25.32 MPa (drying 24 hours), while the longer the drying time, the higher the compressive strength achieved (P slip casting core of sintered powder.

  7. 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.

  8. Simulation studies on sputtering and reflection from compound materials at elevated temperatures

    Science.gov (United States)

    Kenmotsu, T.; Kawamura, T.; Li, Zhijie; Ono, T.; Yamamura, Y.

    Using the ACAT code, we have calculated the energy spectra of boronized graphite under D + ion bombardment. In the case of light ion sputtering, high energy tail of the energy spectra drop sharply compared with the Thompson formula because most sputtered atoms are not due to collision cascade. In this work, we derived a new fitting formula based on the Falcon-Sigmund model instead of the Thompson formula. This fitting formula is in good agreement with the energy spectra in the high energy part. Furthermore, we have simulated surface compositional change in the Hirooka experiment under D + ion bombardment at high temperature. We have applied the ACAT-DIFFUSE code to calculate the compositional change of a boronized graphite. The ACAT-DIFFUSE is a simulation code based on a Monte Carlo method with a binary collision approximation and solves diffusion equations. The ACAT-DIFFUSE was developed to estimate chemical reaction such as methane production. In the present work, we obtained the result which has about 20% in surface composition change.

  9. Investigation of Pristine Graphite Oxide as Room-Temperature Chemiresistive Ammonia Gas Sensing Material

    Directory of Open Access Journals (Sweden)

    Alexander G. Bannov

    2017-02-01

    Full Text Available Graphite oxide has been investigated as a possible room-temperature chemiresistive sensor of ammonia in a gas phase. Graphite oxide was synthesized from high purity graphite using the modified Hummers method. The graphite oxide sample was investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetry and differential scanning calorimetry. Sensing properties were tested in a wide range of ammonia concentrations in air (10–1000 ppm and under different relative humidity levels (3%–65%. It was concluded that the graphite oxide–based sensor possessed a good response to NH3 in dry synthetic air (ΔR/R0 ranged from 2.5% to 7.4% for concentrations of 100–500 ppm and 3% relative humidity with negligible cross-sensitivity towards H2 and CH4. It was determined that the sensor recovery rate was improved with ammonia concentration growth. Increasing the ambient relative humidity led to an increase of the sensor response. The highest response of 22.2% for 100 ppm of ammonia was achieved at a 65% relative humidity level.

  10. Critical phenomenon of the near room temperature skyrmion material FeGe.

    Science.gov (United States)

    Zhang, Lei; Han, Hui; Ge, Min; Du, Haifeng; Jin, Chiming; Wei, Wensen; Fan, Jiyu; Zhang, Changjin; Pi, Li; Zhang, Yuheng

    2016-02-29

    The cubic B20 compound FeGe, which exhibits a near room temperature skyrmion phase, is of great importance not only for fundamental physics such as nonlinear magnetic ordering and solitons but also for future application of skyrmion states in spintronics. In this work, the critical behavior of the cubic FeGe is investigated by means of bulk dc-magnetization. We obtain the critical exponents (β = 0.336 ± 0.004, γ = 1.352 ± 0.003 and β = 5.276 ± 0.001), where the self-consistency and reliability are verified by the Widom scaling law and scaling equations. The magnetic exchange distance is found to decay as r(-4.9), which is close to the theoretical prediction of 3D-Heisenberg model (r(-5)). The critical behavior of FeGe indicates a short-range magnetic interaction. Meanwhile, the critical exponents also imply an anisotropic magnetic coupling in this system.

  11. Low temperature synthesis of bioactive materials Síntese de materiais bioativos a baixas temperaturas

    Directory of Open Access Journals (Sweden)

    L. C. Bandeira

    2011-06-01

    Full Text Available Bioactive materials possess properties that allow them to interact with natural tissues to induce reactions that favor the development and regeneration of those tissues. In this study, silica was prepared by the sol-gel method, using tetraethylorthosilicate as the precursor. The calcium and phosphor sources used here were calcium ethoxy and phosphoric acid, respectively, in ethanol solvent. The solid obtained was dried at 50 ºC. In vitro bioactivity assays were performed by soaking the materials in simulated body fluid (SBF. The samples were characterized by transmission electron microscopy (TEM, thermal analysis and photoluminescence. TEM images of the samples before contact with SBF revealed amorphous aggregates and after 12 days in SBF showed two phases, one amorphous with large quantities of Si and O, and the other a crystalline phase whose composition contained Ca and P. The electron diffraction pattern showed a planar distance of 2.86 Å, corresponding to 2θ = 32.2º. This was ascribed to hydroxyapatite. The Eu III was used as structural probe. The relative band intensity correspondent the transition 5D0 → 7F2 / 5D0 → 7F1 showed a high symmetry surrounding the Eu III ion. These materials, produced by the sol-gel route, open up new possibilities for obtaining bioactive biomaterials for medical applications.Os materiais bioativos apresentam propriedades que permitem a sua interação com um tecido de origem natural podendo induzir a sua regeneração. Neste estudo, o método sol-gel foi utilizado para a preparação de sílica dopada com íons cálcio e fósforo, partindo dos precursores tetraetilortosilicato, etóxido de cálcio e ácido fosfórico em etanol como solvente. O sólido obtido foi seco a 50 ºC. Ensaios de bioatividade foram realizados in vitro em uma solução que simula o fluido corpóreo (SBF. As amostras foram caracterizadas por microscopia eletrônica de transmissão (MET, análise térmica e fotoluminescência. As

  12. 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.

  13. 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.

  14. Improving sustained drug delivery from ophthalmic lens materials through the control of temperature and time of loading.

    Science.gov (United States)

    Topete, Ana; Oliveira, Andreia S; Fernandes, A; Nunes, T G; Serro, A P; Saramago, B

    2018-02-14

    Although the possibility of using drug-loaded ophthalmic lens to promote sustained drug release has been thoroughly pursued, there are still problems to be solved associated to the different alternatives. In this work, we went back to the traditional method of drug loading by soaking in the drug solution and tried to optimize the release profiles by changing the temperature and the time of loading. Two materials commercially available under the names of CI26Y and Definitive 50 were chosen. CI26Y is used for intraocular lenses (IOLs) and Definitive 50 for soft contact lenses (SCLs). Three drugs were tested: an antibiotic, moxifloxacin, and two anti-inflammatories, diclofenac and ketorolac. Sustained drug release from CI26Y disks for, at least 15 days, was obtained for moxifloxacin and diclofenac increasing the loading temperature up to 60 °C or extending the loading time till two months. The sustained release of ketorolac was limited to about 8 days. In contrast, drug release from Definitive 50 disks could not be improved by changing the loading conditions. An attempt to interpret the impact of the loading conditions on the drug release behavior was done using solid-state NMR and differential scanning calorimetry. These studies suggested the establishment of reversible, endothermic interactions between CI26Y and the drugs, moxifloxacin and diclofenac. The loading temperature had a slight effect on the mechanical and optical properties of drug loaded CI26Y samples, which still kept adequate properties to be used as IOL materials. The in vivo efficacy of CI26Y samples, drug loaded at 60 °C for two weeks, was predicted using a simplified mathematical model to estimate the drug concentration in the aqueous humor. The estimated concentrations were found to comply with the therapeutic needs, at least, for moxifloxacin and diclofenac. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Survival of bacteria in nuclear waste buffer materials. The influence of nutrients, temperature and water activity

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, K.; Motamedi, M. [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology; Karnland, O. [Clay Technology AB, Lund (Sweden)

    1995-12-01

    The concept of deep geological disposal of spent fuel is common to many national nuclear waste programs. Long-lived radioactive waste will be encapsulated in canisters made of corrosion resistant materials e.g. copper and buried several hundred meters below ground in a geological formation. Different types of compacted bentonite clay, or mixtures with sand, will be placed as a buffer around the waste canisters. A major concern for the performance of the canisters is that sulphate-reducing bacteria (SRB) may be present in the clay and induce corrosion by production of hydrogen sulphide. This report presents data on viable counts of SRB in the bedrock of Aespoe hard rock laboratory. A theoretical background on the concept water activity is given, together with basic information about SRB. Some results on microbial populations from a full scale buffer test in Canada is presented. These results suggested water activity to be a strong limiting factor for survival of bacteria in compacted bentonite. As a consequence, experiments were set up to investigate the effect from water activity on survival of SRB in bentonite. Here we show that survival of SRB in bentonite depends on the availability of water and that compacting a high quality bentonite to a density of 2.0 g/cm{sup 3}, corresponding to a water activity (a{sub w}) of 0.96, prevented SRB from surviving in the clay. 24 refs.

  16. Understanding defect related luminescence processes in wide bandgap materials using low temperature multi-spectroscopic techniques

    DEFF Research Database (Denmark)

    Prasad, Amit Kumar

    3+; this is possibly related to spin-lattice interaction during resonant excitation. I also examined the YPO4:Sm,Ce system, a model analogue material for feldspar to understand the tunneling mechanism in randomly distributed defects. For the first time, a precise mapping of the energy levels......+) can be adequately described using the prevalent mathematical model of excited-state tunneling. Finally, inspired by the results of YPO4:Ce, Sm, I discovered a Stokes shifted infra-red photoluminescence (IRPL) signal in feldspar. Current methods of OSL rely on transfer of electrons from the...... important technique developments in my thesis. Firstly, based on the model of the red edge effect, a simple method is proposed for estimation of the width of the band tail states in feldspar. Secondly, it is shown that the infra-red photoluminescence (IRPL) technique can be used for non-destructive probing...

  17. 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.

  18. 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.

  19. 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.

  20. Lead-free BNT-based composite materials: enhanced depolarization temperature and electromechanical behavior.

    Science.gov (United States)

    Bai, Wangfeng; Zheng, Peng; Wen, Fei; Zhang, Jingji; Chen, Daqin; Zhai, Jiwei; Ji, Zhenguo

    2017-11-14

    The development of (Bi0.5Na0.5)TiO3-based solid solutions with both high depolarization temperature Td and excellent piezoelectric and electromechanical properties for practical application is intractable because improved thermal stability is usually accompanied by a deterioration in piezoelectric and electromechanical performance. Herein, we report a 0-3 type 0.93(Bi0.5Na0.5)TiO3-0.07BaTiO3 : 30 mol%ZnO composite (BNT-7BT : 0.3ZnO), in which the ZnO nanoparticles exist in two forms, to resolve the abovementioned long-standing obstacle. In this composite, Zn ions fill the boundaries of BNT-7BT grains, and residual Zn ions diffuse into the BNT-7BT lattice, as confirmed by XRD, Raman spectroscopy, and microstructure analysis. The BNT-7BT composite ceramics with a 0-3 type connectivity exhibited enhanced frequency-dependent electromechanical properties, fatigue characteristics, and thermal stabilities. More importantly, low poling field-driven large piezoelectric properties were observed for the composite ceramics as compared to the case of the pure BNT-7BT solid solution. A mechanism related to the ZnO-driven phase transition from the rhombohedral to tetragonal phase and built-in electric field to partially compensate the depolarization field was proposed to explain the achieved outstanding piezoelectric performance. This is the first time that the thermal stability, electromechanical behavior, and low poling field-driven high piezoelectric performance of BNT-based ceramics have been simultaneously optimized. Thus, our study provides a referential methodology to achieve novel piezoceramics with excellent piezoelectricity by composite engineering and opens up a new development window for the utilization of conventional BNT-based and other lead-free ceramics in practical applications.